Journal of East China Normal University(Natural Science)

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An SIS epidemic model driven by a class of truncated stable processes

ZHANG Zhen-zhong, ZHANG Quan, YANG Hong-qian, ZHANG En-hua

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 1-12,38. DOI: 10.3969/j.issn.1000-5641.2019.01.001

Abstract （407）

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A susceptible-infected-susceptible (SIS) epidemic model driven by spectrally positive α-stable processes is considered. Firstly, the uniqueness and the existence of the global positive solution are proved. Next, by using Khasminskii's lemma and the Lyapunov method, conditions for the existence of a unique stationary distribution are given. In addition, the model is shown to be exponentially ergodic. Finally, conditions for extinction of the model are given.

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Estimation of loss reserves based on a hierarchical bayesian model

ZHANG Yi, LIU Zhi-qiang, ZOU Si-si, WEN Li-min

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 13-23. DOI: 10.3969/j.issn.1000-5641.2019.01.002

Abstract （309）

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Traditional loss reserve models are mainly based on aggregate loss triangles, in which the entries are obtained by summations of individual loss data. The summation procedures inevitably cause wastage of information contained in the raw individual data. Though this method is simple, it results in a larger error in the estimate of loss reserves. Individual loss reserve models emerging in recent years have failed to consider dependencies between policies. This article assumes the existence of certain common random effects between policies in the same accident year. Thus, a hierarchical bayesian model is built for individual data loss reserves. Using the ideas of credibility theory, we get the credibility estimate of loss reserves in each accident year, and thus the total reserve. In addition, the estimation of structural parameters and development factors are discussed. And the statistical properties are derived for those estimators of structural parameters. Finally, a numerical example is given to show the calculations with our estimators, and simulations are done to compare the mean square of reserve estimator between an individual loss model and an aggregate data model.

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Lie symmetry analysis, Bäcklund transformation and exact solutions for a class of fourth-order partial differential equations

DAI Hui-ju, LI Lian-zhong, WANG Qi, SHA An

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 24-31. DOI: 10.3969/j.issn.1000-5641.2019.01.003

Abstract （404）

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This paper investigates a class of variable coefficient partial differential equations. By using the homogeneous balance method, the Bäcklund transformation is obtained, which leads to exact solutions for the equation. By applying Lie symmetry analysis, the symmetries and vector field of the equation are obtained. Then, by means of a similarity transformation, the partial differential equations are reduced to ordinary differential equations. Solving the reduced equations, we investigate the exact solutions to the equations concisely using the power series expansion method.

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The upper semi-continuity of the random attractor of the plate equation with linear memory

WANG Yi, MA Qiao-zhen

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 32-38. DOI: 10.3969/j.issn.1000-5641.2019.01.004

Abstract （313）

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Based on the existence of random attractors in the plate equation with linear memory and additive noise, the upper semi-continuity of the random attractor is proved when the coefficient of the noise term goes to zero.

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L(2, 1)-labelling of Halin graphs with a maximum degree of seven

CHEN Xiao-feng, WANG Yi-qiao

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 39-47,57. DOI: 10.3969/j.issn.1000-5641.2019.01.005

Abstract （431）

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A Halin graph is a plane graph G=T ∪ C, where T is a tree with no vertex of degree 2 and at least one vertex of degree 3 or more, and C is a cycle connecting the leaves of T in the cyclic order determined by the drawing of T. After structural analysis of Halin graphs, we show that the L(2,1)-labelling number of every Halin graph G with a maximum degree 7 is at most 10.

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A co-modelling approach for cyber-physical systems with SysML/MARTE/pCCSL

HUANG Ping, DU De-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 48-57. DOI: 10.3969/j.issn.1000-5641.2019.01.006

Abstract （355）

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Cyber-physical systems (CPS) are multi-dimensional complex systems that integrate computing, networks, and physical environments. The modelling for such heterogeneous systems is actively researched. However, there still lacks a systematic approach to model characteristics of CPS, such as heterogeneity, uncertainty, hardware/software coordination, and Non-Functional Properties (NFP). In this paper, we propose a co-modelling approach that relies on SysML (System Modeling Language)/MARTE (Modeling and Analysis of Real-Time and Embedded Systems)/pCCSL (p Clock Constraint Specification Language) to model different aspects of CPS from different points of view, including structure, behavior, clock constraints, and NFP. The novelty of our approach lies in the use of pCCSL to specify the interaction and synchronization to explicitly model the logical consistency between models. Meanwhile, to capture characteristics of CPS, such as stochastic behavior and continuous behavior, we build upon some meta-models of SysML/MARTE. Finally, to demonstrate the feasibility of our co-modelling approach, we present various models of an energy-aware building as a case study.

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Recursive algorithm for NoGo based on value evaluation

GUO Qian-yu, CHEN You-guang

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 58-65. DOI: 10.3969/j.issn.1000-5641.2019.01.007

Abstract （651）

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First, this paper introduces the rules of the game NoGo. Next, we review current methods of artificial intelligence and their respective shortcomings. Then, the article shows an analysis of the game theory characteristics of NoGo and proposes a value evaluation function. Based on this function, a multi-layer recursive algorithm to the artificial intelligence of NoGo can be constructed, which addresses the problem of high complexity in time and space in the present algorithm. Finally, the paper demonstrates the capability of this algorithm and provides results that the program against with the famous open source software OASE-NoGo, which achieved a winning rate of more than 90%. In a typical situation, it demonstrates that the algorithm is better than existing algorithms in computing, and proves the feasibility and effectiveness of this method.

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Multi-strategy gravitational search algorithm based on dynamic grouping

ZHANG Qiang, WANG Mei

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 66-75. DOI: 10.3969/j.issn.1000-5641.2019.01.08

Abstract （311）

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A multi-strategy gravitational search algorithm based on dynamic grouping is proposed in this paper. At the initial stage of the algorithm iteration, adaptive grouping strategies are used to optimize populations. Only the least-optimal individuals are updated in each group. The cloud model theory is used to improve the evolutionary behavior of the optimal individuals. In the later part of the algorithm iteration, the populations are divided into dominant and extension subgroups. The differential mutation operator is subsequently used to update the dominant subgroups to improve the precision and speed of the optimization. Tent chaos theory is used to update the extension subgroups to complete the individual variation. Typical complex function tests show that the algorithm has good convergence accuracy and computational speed.

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Program for calculating the integer order of Bessel functions with complex arguments

REN Hong-hong, GUO Ying-chun, WANG Bing-bing

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 76-82,92. DOI: 10.3969/j.issn.1000-5641.2019.01.009

Abstract （450）

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Fortran source code for calculating the integer order of Bessel functions of the first kind with complex arguments is presented. The method is based on the backward recurrence relation of Bessel functions. Values of the Bessel function generated by our program are in-agreement with the values generated by Matlab to at least 12 significant digits. We use the program to calculate the integer order of Bessel functions of the first kind with pure imaginary arguments, provided by Xu Shiliang's Fortran algorithm assembly. The results show that the first 6 significant digits are accurate. We also analyze the algorithm for calculating Bessel functions with complex arguments, which use the infinite sum of the product of the real arguments of the Bessel function and the pure imaginary arguments of the Bessel function, provided by Xu Shiliang's algorithm assembly. The results show that this algorithm does not always get accurate values for Bessel functions with complex arguments. The reason lies with the fact that the term in the sum larger than the function value causes the loss of significant digits.

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Comparison of the efficiency of equilibrium and nonequilibrium molecular dynamic simulations of molecular solvation free energies

LI Peng-fei, WANG Mei-ting, MEI Ye

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 83-92. DOI: 10.3969/j.issn.1000-5641.2019.01.010

Abstract （390）

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In this study, we used calculations to determine the solvation free energies of 13 side chain analogs of neutral amino acids in water to compare the performance of equilibrium and nonequilibrium molecular dynamic simulations on high-performance computers. We found that nonequilibrium molecular dynamic simulations have the same accuracy as equilibrium molecular dynamic simulations in calculations for solvation free energies. From the perspective of efficiency and computational cost, the nonequilibrium method is more efficient and requires less computational time.

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Preparation of photocatalytic materials MIL-125(Ti)/BiOI and photocatalytic performance study

HUANG Xian-zhi, PIAO Xian-qing, CAI Ya-guo

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 93-104,114. DOI: 10.3969/j.issn.1000-5641.2019.01.011

Abstract （501）

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With pentahydrate bismuth nitrate (Bi(NO₃)₃5H₂O), potassium iodide (KI), and MIL-125(Ti) as raw materials, ethylene glycol as solvent, and citric acid as the structural inducer, heterojunction structure light catalyst MIL-125(Ti)/BiOI was prepared through one-step coprecipitation. The effect of photocatalytic degradation of Rhodamine B in visible light was also tested. By a series of measurements, including XRD, PL, SEM, BET and UV-Vis, we researched the relationships between structure, morphology, spectrum and the catalytic performance of the catalyst. Furthermore, the catalytic mechanism was analysized via energy band structure. The results indicated that by adjusting the ratio of Ti/Bi, MIL-125(Ti)/BiOI has a good degradation effect on Rhodamine B under visible light radiation, which is stable and can be applied to industrial applications.

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Optimization of parallel method of moments based on KNL many-core processors

GU Zong-jing, ZHAO Xun-wang, LIU Ying-yu, LIN Zhong-chao, ZHANG Yu, ZHAO Yu-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 105-114. DOI: 10.3969/j.issn.1000-5641.2019.01.012

Abstract （472）

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The parallel method of moments (MoM) is successfully optimized using the MPI+OpenMP hybrid programming strategy, based on the second-generation Intel Xeon Phi many-core processor platform, codenamed Knights Landing (KNL). Using OpenMP programming technology, the utilization rate of the CPU (Center Processing Unit) is increased, and the computing resources of KNL are fully utilized. The introduction of threads substantially reduces the inter-process redundant integrals in the filling matrix process. In order to give full play to the advantage of KNL's 512-bit vector width, the efficiency of the loop structure is further enhanced through vector optimization. For the matrix solution process, which typically requires intensive computation and high CPU utilization, MPI (Message Passing Interface) communication time is reduced and the solution process is accelerated by introducing an OpenMP programming strategy. Numerical results show that the efficiency of solving complex electromagnetic problems by parallel MoM is greatly improved through optimization on the KNL many-core processor platform.

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Node localization of wireless sensor networks based on the kernel matrix ISOMAP algorithm

YANG Hai, LI Bing

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 115-123. DOI: 10.3969/j.issn.1000-5641.2019.01.013

Abstract （329）

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Position information is nonlinear in the node localization of wireless sensor networks (WSN). Based on the robust ability of multivariate linear regression of partial least squares (PLS), and in combination with nonlinear data dimension reduction of manifold learning, a novel kernel matrix ISOMAP (Isometric Feature Mapping) algorithm is proposed. Geodesic distances between nodes are used as a measure of dissimilarity, and the contribution rate is then used to find and delete the "short circuit" edge. The matrix constructed by a double-centered transformation and the kernel transformation trick is mapped to a high dimensional feature space; finally, the relative position is obtained by PLS. Compared with the traditional ISOMAP algorithm and the multidimensional scale method (MDS), simulation results indicate that the proposed algorithm has good topology stability, generalization properties, robustness, positioning accuracy, and lower computational complexity.

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Application of R language graphics in biological research

LAN Yang, HE Xiu, ZHU Cheng-xu, ZHANG Yu-juan

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 124-135,143. DOI: 10.3969/j.issn.1000-5641.2019.01.014

Abstract （655）

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The R programming language offers powerful statistical analysis, data processing, and visualization capabilities, which can run on Windows, Linux, and Mac operating systems; the software allows users to show scientific research data through graphics by writing new code or adjusting existing code. However, it is difficult to learn R's programming code and use R packages, so R is not commonly favored by novices in the scientific research community. Based on the context of bioscience fields and data from published papers, public databases, and the National Bureau of Statistics, this study demonstrates how to plot high quality maps, heat maps, functional networks, Venn diagrams, and column charts using R, R Studio, and R-packages. To facilitate the use of R, we offer detailed scripts for biological researchers. After comparing R with other graphing software, this study provides good examples and discussions of how to reasonably and intuitively present results in biological research. We hope R will become the preferred plotting tool for elementary biological researchers in their learning and research activities.

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Spatial difference and discussion of water-use efficiency in China under objective constraint

LIAO Yu-xin, ZHANG Yong, GU Run-zhu

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 136-143. DOI: 10.3969/j.issn.1000-5641.2019.01.015

Abstract （380）

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The proposal of the Water Saving Society (WSS) and the strictest water resource management system introduced clearer and stricter requirements for water use in China. To calculate the constraint of the set objectives on water use, this study defined Objective Constraint Strength (OCS) for water regulation, and further compared OCS of agricultural and industrial water-use efficiency for 31 provincial regions in China. The study also carried out scenario analysis on seven different types of areas and proposed advice on WSS construction.

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Comparison of growth and photosynthesis characteristics of native and exotic salt marsh vegetation under elevated temperature and waterlogging conditions

LI Shi-hua, XIE Li-na, CHEN Wei, FEI Bei-li, YUAN Lin, GE Zhen-ming

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 144-155. DOI: 10.3969/j.issn.1000-5641.2019.01.016

Abstract （330）

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Growth and photosynthesis characteristics of native Phragmites australis and exotic Spartina alterniflora, the dominant salt marsh species in China's coastline, grown under elevated temperature and waterlogging conditions, were investigated. The results showed that elevated temperature increased the shoot height, leaf area, maximum rate of photosynthesis, and the apparent quantum yield of P. australis under non-waterlogging (Non-W) and shallow-waterlogging (S-W) conditions. However, the effect was negligible for the growth and photosynthesis parameters of P. australis in deep-waterlogging (D-W) conditions. The shoot height of P. australis reached a maximum, but the leaf area was lowest in a D-W state, indicating morphological adaption to waterlogging. D-W conditions significantly decreased the photosynthesis and chlorophyll fluorescence parameters of P. australis during the middle and later growth periods, compared to Non-W and S-W conditions. Both temperature elevation and waterlogging increased the growth, photosynthesis and chlorophyll fluorescence parameters of S. alterniflora, and the degree of increase under elevated temperature was greater than that of P. australis. Differences in growth and photosynthesis of S. alterniflora between the waterlogging treatments were not notable throughout the growing period. Analysis of variance showed that the effect of elevated temperature on the eco-physiological characters of P. australis was season-dependent, and the impact of waterlogging treatment was more notable with some interaction between the treatments. The effect of temperature elevation on photosynthesis parameters of S. alterniflora was notable, but not for the waterlogging treatment. We suggest that anticipated climate warming and rises in sea level might be beneficial to the exotic marsh species.

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Variations in organic carbon and its impact on tidal creeks within vegetation communities in the coastal wetlands of the Yangtze Estuary

FEI Bei-li, XIE Li-na, LI Shi-hua, CHEN Wei, GE Zhen-ming

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 156-165. DOI: 10.3969/j.issn.1000-5641.2019.01.017

Abstract （386）

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Tidal creeks are identified as an important pathway for carbon exchange between coastal wetlands and the adjacent environment. This study investigated the seasonal variations in dissolved organic carbon (DOC) and particulate organic carbon (POC) in tidal creeks within typical vegetation communities (Poaceae and Cyperaceae) in the coastal wetlands of the Yangtze Estuary. The results showed that during ebb the concentrations of organic carbon components changed gradually along the altitude gradient from high marsh to low-lying shallow water areas outside the creeks. Generally, spring tides increased the organic carbon abundance in both creeks, relative to neap tide. In the Poaceae creek, with high plant biomass and soil carbon stocks, the DOC concentrations were significantly higher compared to the Cyperaceae creek during ebb across all seasons. In contrast, the POC contents were lower in the Poaceae creek compared to the Cyperaceae creek. The results of this study indicated that the Poaceae creek functioned as a net export (source) of DOC throughout the year but as a net sink of POC, and the Cyperaceae creek functioned as a net source of organic carbon over all seasons.

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Convergence analysis of iterative methods for strictly sub-diagonally dominant linear equations

CAI Jing

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 1-6,55. DOI: 10.3969/j.issn.1000-5641.2019.02.001

Abstract （415）

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The Jacobi iterative method, Guass-Seidel iterative method, and SOR iterative method are commonly used in solving linear equations. When the coefficient matrix of a system of linear equations is strictly sub-diagonally dominant, we demonstrate that the Jacobi, Guass-Seider, and SOR iterative methods are all convergent. By comparing the upper bounds of error for the three iterative methods, we show that the upper bound of error for the Guass-Seidel iterative method is minimal.

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Weight one Eisenstein series associated with imaginary quadratic fields

SHEN Li-chien

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 7-20. DOI: 10.3969/j.issn.1000-5641.2019.02.002

Abstract （389）

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We consider a family of weight one Eisenstein series associated with the imaginary quadratic fields. The subspace of the Eisenstein series associated with the Kronecker symbol is characterized by the quadratic forms generated from the genus theory of Gauss; we will derive a family of identities connected with these quadratic fields.

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Conservation laws and self-consistent sources for a super-HU equation hierarchy

FANG Fang, HU Bei-bei

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 21-31. DOI: 10.3969/j.issn.1000-5641.2019.02.003

Abstract （289）

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In the present paper, a super-HU hierarchy was constructed based on super-matrix Lie algebra and super-trace identity. In addition, an integrable super-HU equation hierarchy with self-consistent sources was established. Finally, we set up infinitely many conservation laws for an integrable super-HU equation hierarchy by introducing two variables F and G.

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Average homogeneous and non-homogeneous weighted receiving time in recursive weighted Koch networks

ALHADDAD Mansour A. A., MOHAMMAD Gareeb

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 32-48. DOI: 10.3969/j.issn.1000-5641.2019.02.004

Abstract （367）

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In this paper, we introduce the recursive homogeneous weighted Koch network model for real systems with a scaling factor t ∈ (0, 1) and the non-homogeneous model with scaling factors t, s∈ (0, 1) or t, r, s ∈ (0, 1). These models were constructed using the recursive division method and motivated by experimental study of aviation networks and metabolic networks. As a process of fundamental dynamics, we study the recursive homogeneous and non-homogeneous weighted Koch networks with a random walk; for all steps, the walker who is starting from an existing node moves uniformly to one of its nearest neighbors Γ(j) lying on the layers L_e, e=0, 1, …, m. In order to study homogeneous and non-homogeneous models, the recursive division method and singular value decomposition were used to calculate the sum of the mean weighted longest paths (MWLP) for all nodes absorbed at the target node placed in one of the merging nodes {p_i:i=1, 2, 3}. Finally, in a large network, the average weighted receiving time (AWRT) for homogeneous and nonhomogeneous models grows sub-linearly with the network's order.

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Borel directions of solutions of a second order linear complex differential equation

WEI Wen-long, HUANG Zhi-gang

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 49-55. DOI: 10.3969/j.issn.1000-5641.2019.02.005

Abstract （365）

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In this paper, we consider the Borel directions of solutions of the differential equation f" + A(z)f' +B(z)f=0. By using Nevanlinna's value distribution theory and assuming that A(z) is extremal for Yang's inequality, we provide conditions for B(z) that guarantee that every non-trivial solution f of the equation is of infinite order; we also calculate the number of Borel directions of these solutions.

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Inverse completion for a class of Hamiltonian matrices

BAI Xiao-li, ZHANG Lan

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 56-62,68. DOI: 10.3969/j.issn.1000-5641.2019.02.006

Abstract （345）

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In this paper, the inverse completion of a class of Hamiltonian matrices is studied by applying rank theory and invertible conditions for matrices. Taking advantage of the structural characteristics of Hamiltonian matrices, the sufficient and necessary conditions for the existence of solutions are proved and the expression of solutions are obtained. Furthermore, the conclusions are extended to anti-Hamiltonian matrices, and the corresponding results are obtained. Finally, some examples are used to verify the conclusions.

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Localized theorems of finite groups with M_p-supplemented subgroups

BAO Hong-wei, LI Feng-qing, ZHANG Jia, TANG Ju-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 63-68. DOI: 10.3969/j.issn.1000-5641.2019.02.007

Abstract （332）

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A subgroup H of G is M_p-supplemented in G, if there exists a subgroup B of G such that G=HB and TB < G for every maximal subgroup T of H with|H:T|=p^α. Based on the idea of localization, by using the M_p-supplemented properties of some primary subgroups to study the structure of finite groups, we obtained sufficient conditions for p-nilpotent and p-supersolvable groups.

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Dynamic routing algorithm based on local information in a free-scale network

HAN Ding-ding, LIU Kang, TANG Ming

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 69-76,96. DOI: 10.3969/j.issn.1000-5641.2019.02.008

Abstract （398）

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We proposed a packet routing algorithm with two tunable parameters, α and β, which control the routing preference of degree and queue length, respectively, based on local information in a scale-free network. By adjusting the parameters to change network transmission capability, we found an optimal combination of the two parameters.Other dynamic properties, including average packet travel time and traffic load were also studied. Simulation research showed that the proposed algorithm not only reducedpacket loss rates, but also improved transmission capability and alleviated traffic congestion. We also compared the algorithm with other classical routing algorithms, based on real networks, and the proposed algorithm also displayed good results.

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A Reference Model approach for developing agricultural big data infrastructures

ZHAO Zhi-ming, LIAO Xiao-feng, WANG Xiao-ling, RUAN Chun-sheng, ZHU Yi-feng, FENG Dong-sheng

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 77-96. DOI: 10.3969/j.issn.1000-5641.2019.02.009

Abstract （536）

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Big data infrastructures provide services for the management of data over the course of their lifecycle, and offer users the ability to effectively discover and access data for different application purposes. These emerging infrastructures essentially enable system-level data-centric research; third-party innovation, however, often requires data from different sources. The construction of big data infrastructures faces important interoperability challenges arising from the diverse nature of data acquisition, annotation, and identification performed in different research domains. Moreover, the evolution of different infrastructures is often driven by the specific interests of researchers, in their respective domains, and the constraints of legacy technology. The ENVRI Reference Model (ENVRI RM) is an output of the EU H2020 ENVRI and ENVRI PLUS project, targeting the aforementioned challenges in the context of environmental sciences by modeling environmental research infrastructures with a multi-viewpoints framework; these viewpoints include science, information, computation, engineering, and technology. Each viewpoint describes concrete aspects of a system definition and forms a mechanism to improve the interoperability across the whole system as well as alignment with existing legacy systems. The challenges encountered in the Shanghai Agricultural Big Data Infrastructures construction work are similar to those detected in the ENVRI RM, which provides an ideal place to test the generalizability of the ENVRI RM to other domains. Using the ENVRI RM as a reference, this paper presents an Agricultural Reference Model, which includes the five aforementioned viewpoints, but with consideration of the specifics of the agricultural domain, to address the problems encountered in revising and upgrading the Shanghai Agricultural Big Data Infrastructures. Two use cases are introduced to demonstrate its effectiveness. One is to improve the requirement engineering procedure with the community and role context captured using the Agricultural Reference Model. The other is to upgrade the large volume of existing systems to increase interconnections via the interoperability mechanisms provided by the Agricultural Reference Model.

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Non-orthogonal corrections to wave functions in perturbation theory

SHEN Jia-yin, XUE Xun

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 97-105,115. DOI: 10.3969/j.issn.1000-5641.2019.02.010

Abstract （420）

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Time-independent perturbation theory is fairly accurate for the correction of non-degenerate energy levels, but its accuracy is not satisfactory for the correction of wave functions. After examining the derivation process of perturbation theory, it was found that the reason for the difference in precision may be related to the Orthogonality Assumption. The Orthogonality Assumption-an arbitrary-order modified wave function above zero order is orthogonal to the zero-order wave function-is a condition used in establishing perturbation theory. This paper explored the Orthogonality Assumption in detail and obtained a constraint condition on higher-order modified wave functions by using the normalized properties of the wave function; this condition implies that the accuracy at second-order and above is not suitable for use with the Orthogonality Assumption. It can be shown that without introducing the Orthogonality Assumption, the result of the energy level correction is exactly the same as that of the orthogonal situation, but the result of the modified wave function has a difference that cannot be ignored. This phenomenon can reasonably explain the previous accuracy problem. In this paper, the first three-order non-orthogonal corrective wave function of the one-dimensional charged harmonic oscillator system in the homogeneous electric field is taken as a specific example. By comparing the analytical solution of this system, it can be demonstarted that the non-orthogonal correction of the wave function has higher accuracy than the orthogonal correction. The paper briefly discusses generalization to the degenerate perturbation theory. Combined with recent progress on the Stark problem, it offers a possible method to check for correction of non-orthogonal perturbation.

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Research on parton fragmentation functions of protons

LI Pei-yu, RUAN Jian-hong

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 106-115. DOI: 10.3969/j.issn.1000-5641.2019.02.011

Abstract （412）

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Parton distribution functions and fragmentation functions are fundamental to analyzing high energy experiments.The relationship between the proton valence quark distribution function q(x) and fragmentation function D(x) is analyzed. We find that the simple function D(x)=(1/6)q(x) for a valence quark is a good approximation to describe the available data. We set up a group of new parameterizations of fragmentation functions for protons. Differential cross section data were calculated and compared with recent research. We hope that our work can diminish uncertainties when fitting parton fragmentation functions of protons.

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Complexity of black holes in nonlinear electrodynamics

LI Li, DING Yu-chen, WANG Tao

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 116-121. DOI: 10.3969/j.issn.1000-5641.2019.02.012

Abstract （336）

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Black holes usually have two horizons in nonlinear electrodynamics based on the Einstein gravity theory. Starting with the action and a spherical metric of general forms in this theory, we calculated the electric potential of the black hole as well as the action of the Wheeler-DeWitt patch. The action turned out to be equal to the electric charge multiplied by the potential difference between the inner and outer horizons. Following the conjecture of complexity-action duality proposed recently by Susskind et al., the action can be interpreted as the computational complexity of the quantum states on the Anti-de Sitter boundary. In the special cases of the Reissner-Nordstrom black hole and the Born-Infeld black hole, our general results agree well with the results published in the literature.

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A first principle investigation of organic-inorganic hybrid peroviskite (C₄H₉NH₃)₂PbBr₄

XIE Wei-jia, WANG Qian-qian, XIE Wen-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 122-127. DOI: 10.3969/j.issn.1000-5641.2019.02.013

Abstract （392）

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The structural and electronic properties of the two-dimensional (C₄H₉NH₃)₂PbBr₄ monolayer were investigated by employing first principle electronic structure calculations based on the density functional theory. The optical absorption properties were studied by further analyzing chemical bonding and orbital characteristics. In addition, the influence of a vertical electric field on the electronic structure was also investigated. The results demonstrate that there is a significant external electric field-driven energy gap modulation effect, and that the semiconductor energy gap should be closed when the external electric field is larger than 0.45 V/Å.

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An investigation of the invasive plants in Nanjing Botanical Garden Memorial Sun Yat-Sen

YIN Qian, WANG Hong-jiang, LIU Xing-jian

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 128-134,163. DOI: 10.3969/j.issn.1000-5641.2019.02.014

Abstract （335）

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In order to understand the status of invasive plants in Nanjing Botanical Garden Memorial Sun Yat-Sen, the species, origin, life form, frequency and damage of alien invasive plants were surveyed through routing and sampling. The results showed that there were 65 invasive plants in the botanical garden area; Compositae constituted the largest proportion, accounting for 32.31% of the total, followed by graminaceous plants, accounting for 9.23% of the total. Among the invasive plants, 7 species have caused serious harm, 44 species were introduced from America (the largest point of origin), and most were annual herbs (46.15%). Wasteland and meadows under poor management are the most vulnerable habitat types. The invasion of some species has correlation with the introduction of new plants in the botanical garden.

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The effect of dissolved silicic acid on circular motion behaviors in pennatae: A case study on diatom Navicula arenaria var. rostellata

WANG Feng, ZHAO Li-xia, ZHU Zheng, HU Wen-si, LIU Quan-xing

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 135-146. DOI: 10.3969/j.issn.1000-5641.2019.02.015

Abstract （457）

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Diatoms play an important role in the primary productivity of aquatic systems and in driving the global silicon and carbon cycles in biogeochemistry. Navicula (Navicula arenaria var. rostellata) is a widely distributed diatom species in polluted aquatic and coastal ecosystems. In this study, we treat Navicula as the research object, using f/2+Si culture medium 30 mg/L dSi concentration as a reference to set different dSi concentration gradients (1 mg/L, 15 mg/L, 30 mg/L, 60 mg/L, 120 mg/L, 240 mg/L); based on the Navicula experiments and tracking of cell trajectories and behavior analysis, we explore the effects of different concentrations of dSi on diatom movement behaviors and diffusion coefficients. We found that:Their trajectories display circular motion associated with stochastic disruption. The curvature of the circular arc remains unchanged, and the direction and speed of the motion change significantly at the reverse time point; when the angle is less than 90 degrees; moreover, the velocity decreases before and after the reverse. Their motions display ballistic behavior on short time scales, Brownian-motion on long time scales, and super-diffusion on intermediate time scales. Miniscule and high dSi concentrations effectively inhibit active dispersal, whereas low and intermediate dSi concentrations promote dispersal on diatom cells. Here, our study of individual movement behaviors on diatoms helps to improve our understanding of foraging strategy and aggregation behavior in diatom biofilms; in addition, it provides new ideas on the outbreak of algal bloom, the marine biofouling phenomena, and marine snow phenomena.

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Evaluation of ecosystem services for urban forests in Shanghai based on a distribution measurement methodology

HAN Yu-jie, SUN Wen, ZHANG Wen-wen

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 147-155. DOI: 10.3969/j.issn.1000-5641.2019.02.016

Abstract （332）

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Using continuous observation and the inventory system for forest ecosystems, according to the People's Republic of China standard LY/T 1721-2008 Specifications for assessment of forest ecosystem services in China, combined with forest resource monitoring data from 2016, this study assessed the value of forest ecosystem services in Shanghai. The results showed that the total value of forest ecosystem services in urban forests in Shanghai in 2016 was 12.58 billion yuan and mean value was 127.5 thousand yuan per hectare. The value of the eight service functions was distributed as follows:forest recreation (26.03%), atmosphere environmental purification (22.03%), carbon fixation and oxygen released (20.24%), water conservation (17.14%), biodiversity conservation (9.10%), soil conservation (3.53%), forest nutrition storage (1.84%), contribution of forest to prevent natural calamities(0.09%). From the results of this study, the value of forest recreation was the highest. Forest recreation, atmosphere environmental purification, carbon fixation and oxygen release, and water conservation were the main functions of urban forest services in Shanghai; These features play an important role in building a livable city and establishing "an ecological city".

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Determination of sulfonamides by ultra-high performance liquid chromatography with microextraction

LI Yi, ZHANG Yan, ZHANG Ya-ting, HE Pin-gang, WANG Qing-jiang

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 156-163. DOI: 10.3969/j.issn.1000-5641.2019.02.017

Abstract （344）

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In this study, the development of an analytical method for the determination of chicken meat based on three-phase hollow fiber membrane microextraction ultra-high performance liquid chromatography (HF-LPME-UHPLC) was explored. A three-phase hollow fiber membrane microextraction system was developed to optimize the extraction conditions of HF-LPME:the extractant was n-octanol, the concentration of NaOH in the receiving phase was 200 mmol/L, the concentration of hydrochloric acid in the sample solution was 1.0 mmol/L, the concentration of Na₂SO₄ was 375 g/L, the extraction temperature was 30°, the stirring rate was 300 r/min, and the extraction time was 4 hours. Chicken meat samples were extracted and analyzed by UHPLC. Chromatographic analysis showed that the six sulfonamides reached baseline separation within six minutes. The linearity of the six sulfonamides in the mass range was good with a correlation coefficient of R² > 0.998 9, the enrichment factors ranged from 188 to 950 times, and the detection limit was 0.03~0.1 ng/mL (S/N=3). The recoveries of sulfonamides flagged in chicken were 85.2%~95.6% with relative standard deviations of 3.13%~4.33% (n=5) at a concentration of 50 μg/kg. The studied method is highly sensitive and reproducible, and can be used for the detection of sulfonamides in chicken.

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pH induced regulation of the morphology and properties of polybenzidine submicron rods

WANG Lin, ZHANG Yan-hui, Arzugul MUSLIM, Abida ABDUNAZAR, LAN Hai-die

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 164-173. DOI: 10.3969/j.issn.1000-5641.2019.02.018

Abstract （348）

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Polybenzidine was prepared using micelles of the triblock copolymer PnBA₂₈-b-PS₇₅-b-P2VP₁₀₄ as a template. The effects of different pH values on the morphology and properties of polybenzidine (PBZ) were investigated by regulating the pH value of the micellar solution of the templates. The molecular weight distribution and structure of the triblock copolymer PnBA₂₈-b-PS₇₅-b-P2VP₁₀₄ were determined by size exclusion chromatography (SEC) and nuclear magnetic resonance spectroscopy (¹H-NMR). The morphology and structure of the composites were characterized using a scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). The electrochemical capacitance of the composites was evaluated by chronopotentiometry. The effects of the pH value on the morphology, structure and properties of PBZ were explored in this study. The PBZ particles were submicron and micron rods with uniform distribution and a smooth surface. PBZ rods obtained at pH=5 had an average diameter that ranged from several tens to 200 nm. The uniformity of particle morphologies was found to decrease with an increase in pH value; A electrochemical performance test showed that the specific capacitance of PBZ reached 339.06 F/g at pH=5.

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Analysis of the supply and demand of senior living facilities based on a refined population grid: A case study of Shanghai Pudong New District

ZHANG De-ying, ZHOU Yun-yun, LENG Xie, LI Long, ZHOU Jia-yuan, SHI Run-he

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 174-183. DOI: 10.3969/j.issn.1000-5641.2019.02.019

Abstract （388）

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The contradiction between supply and demand of urban senior living facilities, as a kind of basic public service resource, is especially severe. A refined population grid obtained by state-of-the-art geographic information technology is required to discover the spatial contradiction. This paper took Pudong New District of Shanghai as the research area. The contradiction between the supply and demand of senior living facilities was revealed based on a refined age population grid at a 160-meter resolution, considering the location of facilities, the number of beds, and the health condition of the elderly. The results show that:The refined age population grid can fully illustrate the spatial attributes of the aged population and can be matched with the distribution of beds in senior living facilities spatially, depicting both the supply and demand of senior living facilities visually. The number of beds in senior living facilities meets the requirements of the Shanghai government, namely no less than 3% of the local registered elderly population. The contradiction between supply and demand of senior living facilities depends on location. A distinctive shortage of supply exists in the central area. Smaller facilities and a dense elderly population reflect an urgent demand. Meanwhile, the situation is the reverse in the suburbs, there are multiple overlapping services of facilities. Some facilities in the outer suburbs are too remote to fit the required demand based on the distribution of the elderly population.

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Simulation analysis for remote sensing inversion of wavelength and water depth by the Fast Fourier Transform method

SHEN Si-min, ZHU Shou-xian, KANG Yan-yan, ZHANG Wen-jing, CAO Guang-song

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 184-194,208. DOI: 10.3969/j.issn.1000-5641.2019.02.020

Abstract （423）

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Using the difference in remote sensing reflectivity between wave crest and trough, wavelengths can be inversed by the Fast Fourier Transform (FFT) method to derive the nearshore water depth. Remote sensing images with higher resolution are generally thought to induce less error in marine information inversion. In this study, remote sensing images were replaced by elevation data from ideal equations and numerical simulations to study the effect of data resolution on wavelength inversions and water depths. The results show that low-resolution data result in significant errors in the wavelengths and water depths. But variations in resolution make no difference in reversing the wavelengths and water depths as they reach certain levels. The sub-image size in the FFT method was also studied by simulation analysis. Larger sub-images generate less error in wavelength inversion if the wavelength doesn't vary spatially. On uneven topography, errors from wavelength and water depth inversions are small if the sub-image size is 4-8 times the wavelength and not more than the topography variation; however, when the sub-image is too large or too small, the errors will increase.

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A study of the surficial suspended sediment concentration in response to typhoons in the Yangtze Estuary

WANG Hao-bin, YANG Shi-lun, YANG Hai-fei

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 195-208. DOI: 10.3969/j.issn.1000-5641.2019.02.021

Abstract （403）

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Suspended sediment concentration (SSC) is an important index to measure water quality, and its variations have major influences on seabed erosion/accretion, biological primary productivity, and restoration/loss of land resources. To study the influence of typhoons on the SSC in the Yangtze Estuary, we used surficial SSC data collected at six gauging stations-namely Xuliujing, Qinglonggang, Gaoqiao, Hengsha, Sheshan, and Luchaogang-over the period from 2010 to 2014, as well as continuous data on wind speeds and wave heights over long time scales. The results indicated that wave heights and wind speeds during typhoons were on average 2.2 times and 1.7 times higher, respectively, than those before a typhoon occurred. The mean surficial SSC at the gauging stations also doubled, increasing from 0.32 kg/m³ before typhoons to 0.69 kg/m³ during typhoons. The SSC measured during typhoons was found to be 4 times larger than values observed during calm weather. The typhoons' influences on SSC, moreover, varied across different sections of the Yangtze Estuary. Influences measured at the Sheshan and Luchaogang stations in the outer estuary were the most significant, and the SSC at the two stations increased by 167.1% and 143.7%, respectively. However, the sensitivity of SSC to the typhoons was relatively minor in the inner estuary, where winds' influences were accordingly minimal. Based on long time scale data, the increase of SSC was moderate for wind scales 1-4, and the increase of SSC became evident above a wind scale of 5. Changes in wind speeds and wave heights, resulting from typhoons, were the most dominant factors attributing to the varation in surficial SSC. During typhoon season, the change of surficial SSC caused by typhoons is much greater than the change of surficial SSC due to tidal and runoff effects. This study is beneficial to the protection of coastal engineering during typhoons and has important implications for the study of interdisciplinary fields.

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Existence of weak solutions for a p-Laplace equation with gradient term

LI Zhong-qing

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 1-5. DOI: 10.3969/j.issn.1000-5641.2019.03.001

Abstract （377）

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This paper is devoted to the study of a quasi-linear elliptic equation with gradient term, where the source term f lies in the space L¹. Using the relationship between the coefficient of the zero order term and the source term, the a priori L^∞ estimate and the existence of weak solutions are obtained.

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Pseudo-umbilical space-like submanifolds in locally symmetric pseudo-Riemannian manifolds

BAI Hui-run, LIU Jian-cheng

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 6-12. DOI: 10.3969/j.issn.1000-5641.2019.03.002

Abstract （430）

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In this paper, we study the pseudo-umbilical space-like submanifolds Mⁿ which are immersed into locally symmetric pseudo-Riemannian manifolds N_p^n+p. When Mⁿ is complete non-compact and has a parallel mean curvature vector field, a pinching theorem for the square length of the second fundamental form of Mⁿ is obtained. When Mⁿ is compact and has a parallel mean curvature vector field, then we prove that Mⁿ is totally geodesic.

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Asymptotic behavior of solutions for the classical reaction-diffusion equation with nonlinear boundary conditions and fading memory

WANG Xuan, ZHAO Tao, ZHANG Yu-bao

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 13-23. DOI: 10.3969/j.issn.1000-5641.2019.03.003

Abstract （357）

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In this paper, we study the asymptotic behavior of solutions for the classical reaction-diffusion equation with memory. Through the use of abstract function theory and semigroup theory, the existence of a global attractor in L²(Ω)×L_μ²(R⁺; H¹(Ω)) is proven when the internal nonlinearity and boundary nonlinearity adhere to polynomial growth of arbitrary order as well as the balance condition. This result extends and improves some known results.

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Valuation of American continuous-installment put options

CEN Yuan-jun

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 24-34,62. DOI: 10.3969/j.issn.1000-5641.2019.03.004

Abstract （453）

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Installment options are designed for an investor who is willing to pay a little extra for the opportunity to terminate a contract and reduce losses caused by a void investment position. Because of this extra privilege, installment options are weakly path-dependent. American continuous-installment put options are discussed in this paper. In addition to the right to terminate the contract by stopping the payments at any time, the holder also has the right to exercise the option at any time until maturity; this leads to three potential choices during the holding period:cancel, exercise, or hold on. The mathematical pricing model of this option can be formulated as a parabolic variational inequality, which is a free boundary problem. The existence and uniqueness of the solution can be solved using the penalty method and regular PDE arguments. Different from the standard American put option, this option has two free boundaries irrespective of dividends. Attention is focused on properties of the free boundaries, such as monotonicity, smoothness, and location.

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(d,1)-total labeling of lexicographic products of some classes of graphs

HAN Xin-yin, YAO Min, ZUO Lian-cui, ZHOU Wei-na

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 35-41. DOI: 10.3969/j.issn.1000-5641.2019.03.005

Abstract （439）

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This paper focuses on (d, 1)-total labeling of the lexicographic products of path P_n and path P_m, path P_n and circle C_n, and gets the exact value of the (d, 1)-total number λ_d^T (G) of lexicographic product P_n·P_m, P_n·C_m under certain constraints.

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Simulation of a queuing model with backup waiters and impatient customers

PAN Heng-yi

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 42-54,62. DOI: 10.3969/j.issn.1000-5641.2019.03.006

Abstract （397）

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There are many factors that affect the performance of a queuing system. Under certain assumptions, the number of waiters determines the service efficiency while the presence of impatient customers will affect the service earnings. Traditional queuing theory primarily analyzes queuing models with different time distribution types, while a Monte Carlo simulation model can adapt to the queuing processes of different time distribution types simultaneously. In this paper, several queuing models under common conditions were constructed and simulated by a Monte Carlo simulation; in particular, some commonly used indicators were analyzed. Through a comparison and analysis of the simulation results from these models, it is shown that if the number of waiters is adjusted based on the customer queuing circumstances, it can not only improve service efficiency, but also avoid excessive waste of idle resources and loss of customers. Meanwhile, the simulation results can be used as the basis for setting up queue types and model parameters, as well as a reference for decision making.

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A q-analogy of a nonterminating ₇F₆-series summation

CHEN Ting, WANG Chen-ying

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 55-62. DOI: 10.3969/j.issn.1000-5641.2019.03.007

Abstract （359）

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The modified Abel lemma on summation by parts with a "remainder term" was employed to establish a nonterminating basic hypergeometric series transformation which can be seen as a q-analogy of a known ₇F₆-series summation formula.

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Research on a commodity recommendation algorithm based on reverse furthest neighbor

WANG Kai, LI Bo-han, WAN Shuo, ZHANG An-man, GUAN Dong-hai

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 63-77. DOI: 10.3969/j.issn.1000-5641.2019.03.008

Abstract （428）

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Effective recommendation algorithms can help maximize the value of a product. By studying the user's preferences, we can recommend underlying contents for the user from mass merchandise information. However, most recommendation systems focus on popular products, ignoring those products that are currently not popular but have huge potential. Our recommendation system, based on reverse furthest neighbor (RFN) queries, uses the idea of mining popular products in niche markets. We improve the traditional collaborative filtering recommendation algorithm and adopt a collaborative filtering algorithm based on expert users. The modified algorithm can recommend products with potential value based on the power law, which makes the distribution of minority mined products more visible to users. Experimental results show that the quality of the proposed algorithm is high and is suitable for partially addressing the long tail problem.

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Recognition of mathematical formulas based on support vector machines

LIU Ting-ting, CHENG Tao, JIN Gang-zeng, WANG Xi-kun, GAO Ming

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 78-85. DOI: 10.3969/j.issn.1000-5641.2019.03.009

Abstract （439）

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The recognition of mathematical formulas has been widely used in intelligent education applications, such as searching for answers to questions in image format, automatic marking, and constructing a database of questions. Mathematical formulas often exist in the form of images in many applications; hence, identifying the formulas in these images is an important research topic in the field of intelligent education. Given the complex structure of mathematical formulas, however, recognizing their presence within images is far more complicated than a general optical character recognition task. This paper decomposes formula recognition into three steps:character segmentation, character recognition, and formula reconstruction. First, the characters are separated from an image by using a combination of projection and connected-domain methods. Second, the features of characters are extracted based on the proportion of pixels in a single character relative to pixels in all characters, and a supervised learning model is established to identify each character. Finally, the mathematical formula is reconstructed based on the location of each character in the formula. Experimental results on a real data set show the proposed mathematical formula recognition method can achieve an accuracy of up to 98.0%.

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A public opinion analysis model based on Danmu data monitoring and sentiment classification

YE Jian, ZHAO Hui

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 86-100. DOI: 10.3969/j.issn.1000-5641.2019.03.010

Abstract （505）

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With the rapid development of online video platforms, Danmu has gradually become an important way for people to express their opinions, and it is particularly welcomed by young people. Unlike conventional texts, Danmu texts are generally short, unstructured, and involve Internet slang as well as conventional stop words to express emotions. In this paper, a public opinion analysis model based on Danmu data is proposed. According to the data generation and storage characteristics of Danmu, a hotspot detection-based loop algorithm is proposed for Danmu data collection. Moreover, the sentiment dictionary to distinguish emotional tendencies is expanded to include network vocabularies commonly appearing in Danmu. Finally, based on the convolutional neural network (CNN), we build a classification model to distinguish positive and negative emotions. Experiments show that the public opinion analysis model of this paper can effectively demonstrate public opinion analysis of Danmu data.

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Vital nodes identification by the hybrid K-shell method based on vertex strength

WANG Huan, ZHU Min

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 101-109. DOI: 10.3969/j.issn.1000-5641.2019.03.011

Abstract （432）

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In complex networks, evaluating the importance of individual nodes is of great significance to studying the structure of the network and the propagation process. Based on the location of nodes, the K-shell decomposition algorithm can identify key nodes well; however, it results in many nodes with the same K-shell (Ks) value. Meanwhile, most other algorithms only consider local or global indicators, which can lead to a single factor in judging the importance of a node. In order to better identify key nodes, we propose the extended K-shell and degree of neighbors (EKSDN) algorithm, which considers the global index weighted kernel value of the node and the local index degree of the node comprehensively. A comparison of our experimental results with results from the SIR (Susceptible-Infectious-Recovered) model on real complex networks, show that the proposed algorithm can better quantify the influence of a node.

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Dissociative ionization of allyl bromide in 800 nm and 400 nm intense femtosecond laser fields

LIU Yang, LIU Bo-tong, YANG Yan, SUN Zhen-rong

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 110-119. DOI: 10.3969/j.issn.1000-5641.2019.03.012

Abstract （342）

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Using a homemade time-of-flight mass spectrometer, the ionization and dissociation of gaseous molecular allyl bromide in 800 nm and 400 nm femtosecond laser fields were studied. By analyzing the dependence of ion fragment yields and laser intensity, combined with calculation of the Keldysh parameter, it was shown that multi-photon ionization dominates the ionization process involved in our experiment. Based on a theoretical calculation with the Gaussian 09 software package, flexible force constants and appearance energies of different fragment ions were calculated and dissociation channels were identified. Meanwhile, the results demonstrate that non-resonant multi-photon absorption will lead to simultaneous cleavage of multi-chemical bonds; moreover, the charge distribution of parent ions will steer the reaction pathway.

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Differences in biodiversity of diurnal and nocturnal waterbirds between natural and artificial wetlands: A case study from Caohai Nature Reserve and Yangwanqiao Reservoir, Guizhou Province

LUO Zu-kui, LI Yang, LIU Wen, LI Xing-yuan

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 120-130. DOI: 10.3969/j.issn.1000-5641.2019.03.013

Abstract （494）

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In order to compare diurnal and nocturnal differences in waterbird biodiversity between Caohai Nature Reserve (natural wetland) and Yangwanqiao Reservoir (artificial wetland), we investigated waterbirds primarily using the line transect method during the wintering period from 2010 to 2016. The results from daylight hours indicated that avian abundance, richness, unique species, and the G-F index in Caohai Nature Reserve were all significantly higher than those observed in Yangwanqiao Reservoir, both in spring and winter. The results from nighttime indicated that avian abundance, richness, unique species, and G-F index in Caohai Nature Reserve were all significantly higher than those observed in Yangwanqiao Reservoir in winter. However, there were not significant differences in avian abundance, richness, and unique species observed between the two wetlands in spring. Birds with both different foraging ways and different body sizes varied significantly between the wetlands during daytime and nighttime. The size of mudflats, anthropological disturbances, cement banks, and emerging lake aquatic plants are the main factors that bring about differences in the waterbird community between the two wetlands. The status of habitat exploitation by waterbirds in a plot can be shown if avian distribution is observed both during daytime and nighttime.

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Effect of egg yolk immunoglobulin on an experimental periodontitis model induced by Porphyromonas gingivalis

WANG Fang, XU Xiao-chen, WU Wen-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 131-137. DOI: 10.3969/j.issn.1000-5641.2019.03.014

Abstract （459）

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This study evaluates the therapeutic effects of egg yolk Immunoglobulin (IgY) on periodontitis in an established rat periodontitis model through the growth inhibition of Porphyromonas gingivalis. Experimental periodontitis was induced in mice by ligation of their second molar with medical thread and oral infection with Porphyromonas gingivalis. Periodontitis rats were randomly divided into control, high-dose, and low-dose groups. Each group was comprised of eight rats. The gingival index (GI), plaque index (PI), and bleeding on probing (BOP) were evaluated, the levels of IL-6 and TNF-α were examined, and an X-ray image and histomorphological section were observed after 28 days. Compared with the control, the scores for PI, GI, and BOP and the levels of IL-6 and TNF-α were significantly decreased in the IgY-treated groups. X-ray images showed that the tooth gap narrowed considerably. Pathological observation, furthermore, showed that periodontal fibers were neatly arranged, a small amount of inflammatory cells were infiltrated, the alveolar ridge was not absorbed, and alveolar bone increased. In conclusion, specific IgY can treat periodontitis induced by P.gingivalis in an established rat periodontitis model.

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Variation in germination rates of moss spores using a cryopreservation technique: A case study of spores from six moss species

SUN Li-wei, GAO Xue-di, XU Dan-er, Wang Shu-qin, YANG Zhuo-jun, WANG Jian

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 138-143,154. DOI: 10.3969/j.issn.1000-5641.2019.03.015

Abstract （473）

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To evaluate the applicability of cryopreservation for bryophyte spores, this study explored the effect of dehydration time and low temperature pretreatment; the study was used to identify the optimal conditions for six moss spores collected from different habitats. In addition, varying time periods (1 d, 15 d, 30 d, 90 d, 180 d) of spore cryopreservation were studied under the optimal pretreatment conditions identified. The results showed that:①After dehydration and low temperature pretreatment, the highest germination rates of spores from the six moss species were maintained (87.25%~96.21%). ②Compared to low temperature pretreatment, dehydration seems to be the key point of success for spore cryopreservation. The average spore germination rates ranged from 74.97% to 96.21% when treated with dehydration alone; in comparison, germination rates ranged from 21.73% to 90.94% when pretreated with low temperature alone. ③The average germination rates of spores from five moss species maintained their respective highest level (87.25%~96.21%) after cryopreservation for 1 d and then decreased with the prolongation of storage time; nevertheless, the germination rates still remained at relatively high levels (73.69%~86.60%).④ The average germination rates of spores from Funaria hygrometrica, Pohlia elongate, and Trematodon longicollis after storage for 30 d were 86.49%, 86.60%, and 84.98%, respectively. The germination rates of spores from Bryum blindii and B. caespiticium reached 73.69% and 84.17%, respectively, after storage for 180 d. The study indicates that the procedure for spore cryopreservation could be a simple, stable, and efficient method for storage of bryophyte species in conservation programs.

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A discussion on river network vulnerability in Shanghai based on the PSR model

CHENG Rui-hui, FAN Qun-jie, WANG Yu-kun, LIU Yao-yi, CHE Yue

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 144-154. DOI: 10.3969/j.issn.1000-5641.2019.03.016

Abstract （431）

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This paper combines the concept of vulnerability with a study of river network systems. Shanghai, a typical river network area, is selected as the research area. Based on the PSR model, river network vulnerability is evaluated using 13 indicators for human activity and the river network environment; the aim of this study was to explore vulnerability characteristics and driving mechanisms for regional river networks. The results show that:①Urbanization has caused distinct differences in water system characteristics between Shanghai's regions. The river networks in Pudong and Qingpu are densely distributed, but sparse in the central urban area. ②The overall river network vulnerability in Shanghai is intermediate. Extreme and severe vulnerability areas, accounting for 24.64% of the city's total area, are concentrated in the central urban area and the main urban areas of suburbs. The moderate and mild vulnerability areas account for 22.71% and 31.93%, respectively. ③River network vulnerability features spatial clustering with clear heterogeneity; distribution patterns typically show only "high" or "low" aggregation. ④There is significant correlation between the four land use patterns and river network vulnerability, and construction is the main driving factor driving changes in river network vulnerability.

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Research on service requirements and management strategies for urban parks with extended opening hours in Shanghai

LIU Na-na, GUO Xue-yan, CUI Yi-chong, ZHANG Hong, LU Jun-yao, DA Liang-jun

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 155-163. DOI: 10.3969/j.issn.1000-5641.2019.03.017

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Based on increasing demand for extended opening hours of urban parks at night, this study explores the satisfaction and service requirements of parks, via questionnaires, from the perspective of visitors and park managers. Based on an analysis of facility status, use characteristics, and park management and maintenance, the study puts forward countermeasures to meet the diverse demands of visitors, strengthen safety, and improve management policies, leveraging the management experience of gate-free urban parks in China and abroad. This study, furthermore, aims to provide a valuable reference for improving the quality of urban parks with extended opening hours.

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Community structure and gene expression analysis for nitrifier enrichment cultures

YU Chen-di, HOU Li-jun, ZHENG Yan-ling, LIU Min, YIN Guo-yu, GAO Juan, LIU Cheng, CHANG Yong-kai

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 164-173. DOI: 10.3969/j.issn.1000-5641.2019.03.018

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Nitrifiers were enriched from the tidal sediments of the Yangtze Estuary. Four kinds of nitrifying groups (accounting for 34.7% of the total reads) were detected based on metagenomics, including the recently discovered complete ammonia oxidizers (comammox), strictly nitrite-oxidizing Nitrospira, β-proteobacterial ammonia-oxidizing bacteria, and ammonia-oxidizing archaea. Comammox accounted for 48% of the detected nitrifiers. In addition, gene expression patterns of the nitrifier group (according to the classification in Evolutionary genealogy of genes:Non-supervised Orthologous Groupsdatabase) were analyzed based on metatranscriptomics. The present study showed the community structure and gene expression characteristics of nitrifiers enriched from the tidal sediments, especially the newly discovered comammox. Results enriched our knowledge about the nitrifying communities of estuarine environment, which have great significance to the further molecular ecology research of the nitrification processes.

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State of marine microplastic pollution research and the limitations

LI Dao-ji, Zhu Li-xin, CHANG Si-yuan, ZHANG Feng, WANG Lu

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 174-185. DOI: 10.3969/j.issn.1000-5641.2019.03.019

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Microplastics (less than 5 mm in diameter) are ubiquitously distributed throughout the world's oceans. Marine microplastic pollution has become a global research hotspot and a new frontier in ecological and environmental sciences. The issue has increasingly attracted the attention of scientists, government agencies, and NGOs worldwide. Although the problem of marine plastic pollution was first discovered in the 1970s, it didn't gain attention in the international arena until recent years. Since then, microplastic research has progressed rapidly both globally and in China. However, there are still many problems with the research and response to marine microplastics, requiring further clarification and solutions. This paper first briefly reviews the chronological development of marine microplastic research as well as the role and significance of key events. Thereafter, the paper discusses the state of marine microplastic pollution research and the mitigation efforts in China and abroad, highlighting the current limitations in the research and response to marine plastic and microplastic pollution.

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HIRAS channel selection for atmospheric CO₂ retrievals

LI Lu-han, SHU Jiong, YIN Qiu, ZHAGN Lei, LIU Yan-an

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 186-198. DOI: 10.3969/j.issn.1000-5641.2019.03.020

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The Hyperspectral Infrared Atmospheric Sounder (HIRAS) instrument onboard the Feng Yun-3D (FY-3D) satellite, launched on November 15, 2017, can be employed to retrieve column concentration of CO₂ with strong absorption band sat 15 μm and 4.3 μm. The HIRAS contributes to monitoring constellations for global CO₂ observation by comparison with data of other greenhouse gas sensors. Thus, the selection of a band which is concurrently sensitive to CO₂ changes and resistant to interference from other parameters is one of the most critical tasks to enable use of the satellite for practical applications. First, based on the line-by-line radiative transfer model, the HIRAS radiance in the hyperspectral 15 μm band was simulated for five standard atmospheric models,and the responses of given channels to the perturbation of CO₂ and other atmospheric components (H₂O, O₃, surface temperature, and emissivity) were analyzed. Second,using the signal-to-interference ratio,the CO₂ response, and the Jacobian profiles as criteria, five different sets of channels for each condition were selected by the Optimal Sensitivity Profile (OSP) method; this was accompanied by a discussion of channel differences for different atmosphere stratification. Third, experiments involving different levels of instrumental noise showed that the lower the instrument's noise, the more helpful it is to select a CO₂ sensitive height in the stratosphere. The results of the channel selection in this paper present references for instrument design in the future.

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A study on the inversion of atmospheric temperature and humidity profiles by using CrIS infrared hyperspectral satellite data

SHEN Zhen-xiang, LIU Chao-shun

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 199-210. DOI: 10.3969/j.issn.1000-5641.2019.03.021

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Atmospheric temperature and humidity profile data are basic inputs for numerical weather prediction and climate change assessments, and they are considered indispensable for other scientific research. Improving weather forecast and climate prediction ability by using high spectral satellite data to accurately and quantitatively invert high precision temperature and humidity profiles is of great significance. This paper uses hyperspectral infrared radiation data from the next generation cross-track infrared detector CrIS (Cross-track Infrared Sounder) on the Suomi-NPP (National Polar-orbiting Partnership) satellite as well as reanalysis data of temperature and humidity profiles from the ECMWF (European Centre for Medium-Range Weather Forecasts). In this paper, the D-R (Dual-Regression) inversion algorithm is used to study the inversion of high temperature and humidity profiles. Then, it is compared with measured temperature and humidity profile data from June to Septemberof each year between 2014 and 2016 at the Shanghai Baoshan site and the official temperature and humidity product inversion by NOAA (National Oceanic and Atmospheric Administration)'s official NUCAPS (NOAA Unique Combined Atmospheric Processing System) algorithm. The results show that the total BIAS of the atmospheric temperature profiles retrieved by the D-R algorithm, based on the background field using ECMWF's temperature and humidity reanalysis data, is basically within 1K, and the RMSE (root mean square error) is basically within 2 K, which is equivalent to the NUCAPS algorithm's inversion accuracy. In the lowest layer of the atmosphere, the inversion accuracy of the D-R algorithm remains within 2 K, which is better than the NUCAPS algorithm (RMSE index). The relative humidity at an inversion height below 300 hPa is of the same accuracy as the NUCAPS algorithm, when the RMSE is less than 20% and the BIAS is less than 10%; hence, the inversion result is good and stable. However, when the height is above 300 hPa, the error of the inversion D-R algorithm increases to 30% and the inversion accuracy is reduced.

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Characterization of commuting weakly additive maps on a class of algebras

HUO Dong-hua

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 1-10,18. DOI: 10.3969/j.issn.1000-5641.2019.04.001

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Let A be an algebra with unit 1. A map f:A→A is a weakly additive map if for every x, y∈A there exist t_x,y, s_x,y∈F such that f(x + y)=t_x,yf(x) + s_x,yf(y). We prove that under some conditions, if f is a commuting map, then there exists λ₀(x)∈A and a map λ₁ from A into Z(A) such that f(x)=λ₀(x)x + λ₁(x) for all x∈A. As an application, a class of commuting weakly additive maps on M_n(F) are characterized.

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Oscillation of second-order generalized Emden-Fowler-type differential equations

LI Ji-meng

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 11-18. DOI: 10.3969/j.issn.1000-5641.2019.04.002

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The oscillatory behavior of a class of second-order generalized EmdenFowler-type nonlinear variable delay neutral functional differential equations is studied in this article. By using the generalized Riccati transformation and some analytic techniques, we establish two new oscillation criteria for the equations under the condition ∫_t₀^+∞ a^-1/β(t)dt<+∞. Illustrative examples are provided to show that our results extend and improve those previously reported in the literature, and the results are both practical and implementable.

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A class of delayed HIV-1 infection models with latently infected cells

YANG Jun-xian, XIE Bao-ying

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 19-32. DOI: 10.3969/j.issn.1000-5641.2019.04.003

Abstract （413）

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A class of delayed HIV-1 infection models with latently infected cells was proposed. The basic reproductive number R₀ was defined, and the existence conditions of disease-free equilibrium P₀(x₀, 0, 0, 0) and chronic-infection equilibrium P^*(x^*, ω^*, y^*, v^*) were given. First, the local asymptotic stability of infection-free equilibrium and chronicinfection equilibrium was obtained by the linearization method. Further, by constructing the corresponding Lyapunov functions and using LaSalle's invariant principle, it was proved that when the basic reproductive number R₀ was less than or equal to unity, the infection-free equilibrium P₀(x₀, 0, 0, 0) was globally asymptotically stable; moreover, when the basic reproductive number R₀ was greater than unity, the chronic-infective equilibrium P^*(x^*, ω^*, y^*, v^*) was globally asymptotically stable, but the infection-free equilibrium P₀(x₀, 0, 0, 0) was unstable. The results showed that a latently infected delay and an intracellular delay did not affect the global stability of the model, and numerical simulations were carried out to illustrate the theoretical results.

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An initial-boundary value problem for the generalized Sasa-Satsuma equation on the half-line

DONG Feng-jiao, HU Bei-bei

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 33-41. DOI: 10.3969/j.issn.1000-5641.2019.04.004

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In this paper, we implement the Fokas unified transform method to study initial-boundary value problems of the generalized Sasa-Satsuma equation on the half-line. Assuming that the solution u(x, t) of the generalized Sasa-Satsuma equation exists, we will prove that it can be expressed in terms of the unique solution of a 3×3 matrix Riemann-Hilbert problem formulated in the plane of the complex spectral parameter λ.

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Two-mode coupled KdV equation: Multiple-soliton solutions and other exact solutions

ZHAO Qian, BAI Xi-rui

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 42-51. DOI: 10.3969/j.issn.1000-5641.2019.04.005

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In this paper, multiple-soliton solutions for a new two-mode coupled KdV (nTMcKdV) equation are obtained by using the simplified Hirota's method and the Cole-Hopf transformation. It is shown that these types of multiple solutions exist only for models in which specific values for the nonlinearity and dispersion parameters are included in the models. Furthermore, other exact solutions for an nTMcKdV equation using general values of these parameters are derived by using several different expansion methods such as the tanh/coth method and the Jacobi elliptic function method.

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Existence of entropy solutions for an elliptic equation with degenerate coercivity

DAI Li-li

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 52-61. DOI: 10.3969/j.issn.1000-5641.2019.04.006

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In this paper, we use the truncation method to investigate the existence of solutions for degenerate elliptic problems with variable exponent in weighted Sobolev spaces. With the help of the Marcinkiewicz estimate and using some a priori estimates for the sequence of solutions of the approximate problem, and we choose suitable test functions for the approximate equation and obtain the needed estimates. Then, we obtain the entropy solutions for the elliptic equation in weighted Sobolev spaces with a variable exponent.

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Integral inequalities for generalized harmonically quasi-convex functions on fractal sets

SUN Wen-bing

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 62-71. DOI: 10.3969/j.issn.1000-5641.2019.04.007

Abstract （328）

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In this paper, the author introduces the concept of generalized harmonically quasi-convex functions on fractal sets R^α(0 < α ≤ 1) of real line numbers and establishes generalized Hermite-Hadamard and Simpson type inequalities for generalized harmonically quasi-convex functions. Some applications for α-type special means of real line numbers are given.

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Second-order online portfolio selection strategy with transaction costs

QU Jing-jing, YU Shun-chang, HUANG Ding-jiang

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 72-82. DOI: 10.3969/j.issn.1000-5641.2019.04.008

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Existing portfolio selection strategies based on the online Newton step (ONS) algorithm ignore the role of transaction costs, an indispensable factor in real markets. This paper proposes a new online portfolio selection strategy, the online Newton step transaction cost (ONSC) method, to address this issue. First, we constructed the optimal function by combining second order information of a portfolio with the transaction cost penalty term, and the portfolio was subsequently updated. Then, the sublinear regret bound O(log(T)) was achieved by theoretical analysis. Empirical research on the data sets of four real markets-namely, SP500, NYSE(O), NYSE(N) and TSE-showed that in comparison to semiconstant rebalanced portfolios (SCRP) and other strategies with transaction costs, ONSC achieves the highest accumulated wealth and the smallest turnover. Hence, the research demonstrates the efiectiveness of the algorithm.

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Design and implementation of graduate student cultivation system based on micro-services

YIN Jia-ling, XIA Fan, GU Hang, ZHU Xiang, SUN Chen, WANG Ye, DONG Qi-wen, SONG Shu-bin, FU Yun-bin

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 83-96. DOI: 10.3969/j.issn.1000-5641.2019.04.009

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With the development of information technology, the model of graduate student management has changed. In terms of the service target, the existing graduate student cultivation management system of East China Normal University (ECNU) was primarily targeted at school administrators. With the promotion of a "student-centered" educational concept, however, the existing system proved unable to meet student requirements. With the expansion in enrollment, the scale and growth rate of data in the systems are ever increasing. The data used by the graduate student management system has changed from a small set of simple data to a large set of complex data on teaching behavior. Based on the above reasons, ECNU has adopted an open source framework, such as AngularJS and Spring Boot, to complete the system's independent development. In terms of architecture, the system aims to use micro-services architecture to automate continuous deployment for developing an intelligent graduate student information platform that provides graduate students, teachers, and administrators with personalized services and can be quickly iterated by developers.

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User requirements oriented service recommendation for a cloud desktop

GAO Zhi-qiang, YUAN Min, ZHANG Jie

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 97-110. DOI: 10.3969/j.issn.1000-5641.2019.04.010

Abstract （322）

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A cloud desktop is a new type of cloud service that can provide customizable and shared resources. As a searchable cloud service, it can be configured to satisfy individual demands. This paper presents a cloud desktop recommendation method based on ontology, a description of user requirements, and matching from both resource providers and consumers. In one case, the service functions and non-functional features of a resource provider are analyzed, and ontologies are used to match user requirements with a candidate desktop image to find a reliable cloud desktop. In another case, user requirements for resource consumers are analyzed, and we utilize collaborative filtering methods to allow the user to select an appropriate cloud desktop resource, avoiding potential deviations in user resource requests. Experimental results show that the proposed method improves the accuracy of the cloud desktop in the resource discovery and selection process; moreover, the proposed method can recommend more suitable data resources according to the potential needs of users.

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An end-to-end Chinese speech synthesis scheme based on Tacotron 2

WANG Guo-liang, CHEN Meng-nan, CHEN Lei

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 111-119. DOI: 10.3969/j.issn.1000-5641.2019.04.011

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The disruptively design for an end-to-end speech synthesis system Tacotron 2, is currently only available in English. This paper is devoted to implementing several improvements to Tacotron 2 and presents a Chinese speech synthesis scheme, including:a pre-processing module to convert Chinese characters into phonetic characters to address the challenge of Chinese character not corresponding to pronunciation, having multiple tones, and having polyphonic words; a pre-training decoder to achieve better sound quality with less corpus given the lack of existing Chinese training corpus; a strategy of weighting the cross-entropy loss and using the multi-layer perceptron, instead of the linear transformation, to predict stop tokens and to solve the Chinese speech synthesis sudden pause problem; and a multi-head attention mechanism to further improve Chinese speech quality. The experimental comparison of the Mel spectrum and the Mel cepstrum distance (MCD) shows that our work is effective and can make Tacotron 2 adapted to the requirements of Chinese speech synthesis.

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A distributed user-friendly Dubbo interface testing platform

LI Yan-li, ZHANG Zong-yong, FENG Jie, LI Zhi-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 120-132,143. DOI: 10.3969/j.issn.1000-5641.2019.04.012

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With the development of online finance, the financial business has become increasingly complex and product iterations have become more frequent. Financial applications have started to use the Dubbo protocol for programming to support this prosperous business. There are some problems, however, in supporting testing of the Dubbo protocol, multiplayer collaboration, maintenance, and data analysis with the current testing tools. First, these tools can only be used to test the Dubbo protocol and the Dubbo testing framework that exists at present is difficult to promote. Second, complex businesses involve multiple applications; the current system does not consider automated collaboration among multiple systems. Third, single-machine automatic testing tools or coded automatic testing frames are not good for multiplayer collaboration in writing automatic test cases and maintenance. Finally, data analysis is usually the execution result when reviewing single-system test cases so it cannot provide a holistic analysis of data. In order to manage a large quantity test cases and support multi-system upgrades, this paper uses distribution technology to design and implement a flexible and visible Dubbo automatic testing platform with the existing testing framework. Based on an interface application, the paper provides visible data-driven and keyword-driven methods and supports the programming of complex test cases. It can also generate the interfaces that you need to test and can generate test cases according to them automatically. This paper describes the architecture of this user-friendly Dubbo testing platform and the management of test cases and execution in a detailed way. Lastly, it shows a comparison of cost vs. time and a comparison of automated test case growth between the old framework and the daily execution results of the new platform's automation testing.

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Experimental investigation of advanced purification of tail water in a rural sewage treatment plant of an ecological riparian zone

YANG Yin-chuan, CHANG Yue-ya, CUI He, HUANG Min-sheng, HE Yan

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 133-143. DOI: 10.3969/j.issn.1000-5641.2019.04.013

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In this paper, four kinds of common fillers natural soil, humus soil, biological ceramist and clinoptilolite were used to design three kinds of ecologic riparian devices (R1, R2 and R3) in different mixing proportions, and the devices were all filled with ryegrass. This study explores the purification ability of different riparian zone treatment units for the tailwater of rural sewage treatment plants, and provides a scientific basis for the application of this process in engineering practice. The results showed that the removal rate of pollutants (not including NH₄⁺-N) by R1 was significantly better than R2 and R3, and the water quality was more stable. The average removal rates of TN, NH₄⁺-N, TP, and COD_Cr were 23.0%, 49.5%, 36.3%, and 25.6% respectively. The contribution of ryegrass to the removal of N and P in the tail water was 23.5% and 22.6% respectively; hence, its purification effect on tail water is confirmed. The average removal rate of NH₄⁺-N in water containing clinoptilolite was the highest (58.2%) with R2. The genus of organisms that remove organic matter from the biofilm of the ecological riparian zone played the dominant role (eg, sphingomonas), while the proportion of bacteria for nitrogen and phosphorus removal was small (less than 2%), This indicates that the removal of organic matter in the tail water of an eco-riparian zone depends primarily on the microbial degradation and transformation of the filler, while the removal of nitrogen and phosphorus depends primarily on the adsorption of the filler and the plant. Hence, subsequent research can strengthen the function of the riparian zone according to the type of pollutants, and try to add clinoptilolite to the existing packing configuration of R1, thereby further strengthening the deep purification effect of the ecological riparian zone on the tail water of rural domestic sewage plants.

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Fuzzy comprehensive assessment of landscape water eco-compositive purifying process in Mengqing Garden

XIAO Bing, YANG Yin-chuan, LU Xin-yu, LI Xin-ran, HUANG Min-sheng, YIN Chao, HE Yan

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 144-155. DOI: 10.3969/j.issn.1000-5641.2019.04.014

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Located on the south side of Suzhou River, an eco-compositive purifying process is run in Mengqing Garden to treat landscape water. Single factor assessment and fuzzy comprehensive assessment (FCA) were utilized to evaluate the water quality classification, respectively. The results showed that the system reduced the concentration of NH₃-N, TN and TP, with removal rates of 29.7%, 55.2%, and 24.3%, respectively, and DO was greatly elevated. The water quality fluctuated throughout the process. The water quality of the Reed Wetland was the worst, inferior to Class V and requires improved management.

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Effect of sulfide on the denitrification potential of sediment in black-odor rivers

WANG Shan, ZHU Jin, HE Yan, HUANG Min-sheng, ZHOU Yun-chang

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 156-164. DOI: 10.3969/j.issn.1000-5641.2019.04.015

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This study aimed to explore the effect of sulfide on sediment denitrification in different concentrations, analyze the response of bacteria, including denitrifying and sulfate-reducing bacteria, and provide a theoretical basis and technical support for improving the denitrification process of sediment in black-odor rivers. The results showed that a low concentration of sulfides (8 mg·L^-1) didn't have a significant effect. In constrast, a moderate concentration of sulfides (40 mg·L^-1, 64 mg·L^-1) promoted the denitrification process; in this range the higher the concentration of sulfides, the faster the rate of nitrate degradation. When the sulfide concentration rises to 96 mg·L^-1 and above, reductive sulfur inhibits denitrification, and the higher the concentration, the more obvious the inhibition. After a period of denitrification of the culture, the bacterial diversity is mainly composed of Proteobacteria, Chlofloflexi, and Bacillus. As the same time, the total number of bacteria in the sediment increased; the abundance ratio of nirS to 16S rRNA gene and dsrB to 16S rRNA gene were 1.42% and 0.05%, respectively. Compared with the original sediment (0.15%, 0.19%), the denitrifying bacteria increased significantly, but the number of sulfate-reducing bacteria decreased.

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Evaluation of water quality before and after treatment at Gongye River and Xiaozhai River in Shanghai

LU Xin-yu, YANG Yin-chuan, XIAO Bing, HUANG Min-sheng, LI Xin-ran, YIN Chao, CAO Cheng-jin

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 165-173. DOI: 10.3969/j.issn.1000-5641.2019.04.016

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The water quality of Gongye River and Xiaozhai River in Putuo District of Shanghai before and after treatment were evaluated in this study. Single factor trend of dissolved oxygen, turbidity, nitrate nitrogen, chlorophyl a, and population density of zooplankton in these two rivers were analyzed; in addition, grey correlation analysis was conducted with total phosphorus, ammonia nitrogen, permanganate index, chemical oxygen demand, and five-day biochemical oxygen demand. The results showed no obvious changes in dissolved oxygen and turbidity before and after treatment. The concentration of nitrate nitrogen decreased initially after treatment. The concentration of nitrate nitrogen decreased initially after treatment, but increased thereafter, meanwhile, the concentration of chlorophyl a rose significantly after treatment. There's an increase in both species and densities of zooplankton with treatment. The grey relational analysis indicated that the water quality of the two rivers was close to Class V before treatment, reached Class I in the short term directly after treatment, and eventually stabilized at Class IV.

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A comparative analysis of the Ocean Health Index and the Pressure-State-Response evaluation methods for Shanghai's ocean ecosystem health

WU Zhen, CHEN Rui-shan

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 174-187. DOI: 10.3969/j.issn.1000-5641.2019.04.017

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The ocean is of great significance to humanity. It not only regulates the global climate, but it also plays a vital role in providing food, livelihood, and entertainment. The 18th National Congress of the Communist Party of China proposed:improving the capabilityfor marine resource exploration, developing the marine economy, protecting the marine ecological environment, firmly safeguarding the rights and interests of the nation's seas, and building a strong maritime nation. As one of the world's mega coastal cities, Shanghai must understand the changing trends and status of its ocean ecosystem health,and the interaction between cities and oceans. The current challenges for Shanghai's ocean coast are marine pollution, land reclamation, and typhoon storms caused by global changes. Based on evaluation methods for ocean ecosystem health, both in China and abroad, this paper compares two different evaluation methods:the Ocean Health Index (OHI) and the Pressure-State-Response (PSR). The paper evaluates the changing trends and status of Shanghai's ocean ecosystem health. The evaluation results of the two methods show that Shanghai's ocean ecosystem became healthier since 2009; it was, however,foundto be in a state of sub-standard health in 2015. The "Pressure-State-Response" (PSR) model, moreover, was found to be most suitable for Shanghai. This study provides scientific advice for the development of land and sea in Shanghai, as well as research cases for other coastal cities.

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Phosphorus content, fractionation, and desorption status in the sediments of major Chinese tidal flats

CHEN Jie, WANG Dong-qi, LI Yang-jie, YU Lin, CHEN Zhen-Lou, XU Shi-yuan

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 188-201. DOI: 10.3969/j.issn.1000-5641.2019.04.018

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This study analyzed the content of total phosphorus (TP) in the sediments of major Chinese tidal flats. It found that the northern flats, separated by the Zhejiang Cixi sampling site, showed low TP content in the surficial and core samples of the Liaoning Liao River delta (0.046%±0.013% surficial, 0.047%±0.015% core) and the Shandong Qingdao mud flats (0.047%±0.009%; 0.055%±0.008%). The average TP in the rest of the northern flats, such as Tianjin Hangu, the Yellow River delta, Jiangsu Yancheng, Shanghai Chongming Dongtan, and Cixi, varied from 0.051% to 0.070%, the highest level in the 12 tidal flats. Except for the Xiamen Jiulong River and Guangdong Pearl River flats (0.051%～0.070%), the TP content values were found to be lower in the southern flats, especially in Fuzhou Minjiang, Gangxi Yingluo Bay, and Hainan Dongzhaigang (0.019%～0.041%). The high TP in the northern flats can be attributed to fluvial sediments carried by high discharge rivers. At the site of high measured TP values, large amounts of Ca-P also were detected (4.16～9.56 μmol g^-1). The concentration of Fe-P in the core samples was lower than the surficial samples. The tidal flats of Hangu, Qindao and Jiulong River exhibited the highest Fe-P levels. Two consecutive and non-consecutive incubation experiments showed various self-release velocities of TP. In the consecutive incubations, the largest release velocity occurred in the Jiulong River delta (0.927±0.312 μmol kg^-1h^-1). The non-consecutive experiments showed a significant increasing trend of TP release velocities in 11 tidal flats, except for the Liao River delta (P<0.01). Among the sites, the Hangu, displayed the highest TP release velocity (1.437±0.325 μmol kg^-1h^-1).

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Study on the safety of sea dikes against coastal erosion in a strong tidal estuary

LI Lu, LIU Xin-cheng, SONG Yong-gang, ZHAO Geng-run

Journal of East China Normal University(Natural Sc 2019, 2019 (4): 202-211. DOI: 10.3969/j.issn.1000-5641.2019.04.019

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High resolution bathymetric data along the Huadianhuiba sea dike, a typical eroding coast on the northern coastline of Hangzhou Bay, was collected to analyze seabed evolution. A wave model covering the Changjiang Estuary and Hangzhou Bay was built to obtain the wave elements along the sea dike. Then, sensitivity analyses were carried out to calculate the impacts of coastal erosion on the wave elements, the required crest elevation, and the intensity of the seaside dike revetment. The results indicate that under a design condition of a 200 year return period with increasing water depth in front of the sea dike, the mean wave height and wave period are almost stable, while the wave length and H₁% are significantly increased. The increased wave length, due to the topography deepening, is found to be a major factor for the subsequent wave run-up, which reduces the defense standard of sea dikes at crest elevation. In addition, the required intensity of the seaside dike revetment increases significantly with the depth of water in front of the sea dike. This indicates that a safety margin should be accounted for in design of the sea dike.

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Journal of East China Normal University(Natural Sc 2019, 2019 (5): 0-00.

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A review of knowledge tracking

LIU Heng-yu, ZHANG Tian-cheng, WU Pei-wen, YU Ge

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 1-15. DOI: 10.3969/j.issn.1000-5641.2019.05.001

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In the field of education, scientifically and purposefully tracking the progression of student knowledge is a topic of great significance. With a student's historical learning trajectory and a model for the interaction process between students and exercises, knowledge tracking can automatically track the progression of a student's learning at each stage. This provides a technical basis for predicting student performance and achieving personalized guidance and adaptive learning. This paper first introduces the background of knowledge tracking and summarizes the pedagogy and data mining theory involved in knowledge tracking. Then, the paper summarizes the research status of knowledge tracking based on probability graphs, matrix factorization, and deep learning; we use these tools to classify the tracking methods according to different characteristics. Finally, the paper analyzes and compares the latest knowledge tracking technologies, and looks ahead to the future direction of ongoing research.

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A survey on coreference resolution

CHEN Yuan-zhe, KUANG Jun, LIU Ting-ting, GAO Ming, ZHOU Ao-ying

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 16-35. DOI: 10.3969/j.issn.1000-5641.2019.05.002

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Coreference resolution is the task of finding all expressions that point to the same entity in a text; this technique is widely used for text summarization, machine translation, question answering systems, and knowledge graphs. As a classic problem in natural language processing, it is considered NP-Hard. This paper first introduces the basic concepts of coreference resolution, analyzes some confusing concepts related thereto, and discusses the research significance and difficulties of the technique. Then, we summarize research advances in coreference resolution, divide them into stages from a technical standpoint, introduce the representative approaches for each stage, and discuss the advantages and disadvantages of various methods. The summarized approaches are five-fold:rule-based, machine learning, global optimization, knowledge base, and deep learning. Next, we introduce benchmark conferences for the problem of coreference resolution; in this context, we explain and compare their corpus and common evaluation metrics. Finally, this paper highlights the open problems for coreference resolution, and discusses trends and directions of future research.

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A review of machine reading comprehension for automatic QA

YANG Kang, HANG Ding-jiang, GAO Ming

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 36-52. DOI: 10.3969/j.issn.1000-5641.2019.05.003

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Artificial Intelligence (AI) is affecting every industry. Applying AI to education accelerates the structural reform of education and transforms traditional education into intelligent adaptive education. The automatic Question Answer system, based on deep learning, not only helps students to answer questions and acquire knowledge in real-time, but can also quickly gather student behavioral data and accelerate personalization of the educational process. Machine reading comprehension is the core module of an automatic Question Answer system, and it is an important technology to understand student problems, document content, and acquire knowledge quickly. With the revival of deep learning and the availability of large-scale reading comprehension datasets, a number of neural network-based machine reading models have been proposed over the past few years. The purpose of this review is three-fold:to introduce and review progress in machine reading comprehension; to compare and analyze the advantages and disadvantages between various neural machine reading models; and to summarize the relevant datasets and evaluation methods in the field of machine reading.

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Research on knowledge point relationship extraction for elementary mathematics

YANG Dong-ming, YANG Da-wei, GU Hang, HONG Dao-cheng, GAO Ming, WANG Ye

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 53-65. DOI: 10.3969/j.issn.1000-5641.2019.05.004

Abstract （474）

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With the development of Internet technology, online education has changed the learning style of students. However, given the lack of a complete knowledge system, online education has a low degree of intelligence and a/knowledge trek0problem. The relation-extraction concept is one of the key elements of knowledge system construction. Therefore, building knowledge systems has become the core technology of online education platforms. At present, the more efficient relationship extraction algorithms are usually supervised. However, such methods suffer from low text quality, scarcity of corpus, difficulty in labeling data, low efficiency of feature engineering, and difficulty in extracting directional relationships. Therefore, this paper studies the relation-extraction algorithm between concepts based on an encyclopedic corpus and distant supervision methods. An attention mechanism based on relational representation is proposed, which can extract the forward relationship information between knowledge points. Combining the advantages of GCN and LSTM, GCLSTM is proposed, which better extracts multipoint information in sentences. Based on the attention mechanism of Transform architecture and relational representation, a BTRE model suitable for the extraction of directional relationships is proposed, which reduces the complexity of the model. Hence, a knowledge point relationship extraction system is designed and implemented. The performance and efficiency of the model are verified by designing three sets of comparative experiments.

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Performance prediction based on fuzzy clustering and support vector regression

SHEN Hang-jie, JU Sheng-gen, SUN Jie-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 66-73,84. DOI: 10.3969/j.issn.1000-5641.2019.05.005

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Existing performance prediction models tend to overuse different types of attributes, leading to either overly complex prediction methods or models that require manual participation. To improve the accuracy and interpretation of student performance prediction, a method based on fuzzy clustering and support vector regression is proposed. Firstly, fuzzy logic is introduced to calculate the membership matrix, and students are clustered according to their past performance. Then, we use Support Vector Regression (SVR) theory to fit and model performance trajectory for each cluster. Lastly, the final prediction results are adjusted in combination with the students' learning behavior and other related attributes. Experimental results on several baseline datasets demonstrate the validity of the proposed approach.

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Transfer learning based QA model of FAQ using CQA data

SHAO Ming-rui, MA Deng-hao, CHEN Yue-guo, QIN Xiong-pai, DU Xiao-yong

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 74-84. DOI: 10.3969/j.issn.1000-5641.2019.05.006

Abstract （388）

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Building an intelligent customer service system based on FAQ (frequent asked questions) is a technique commonly used in industry. Question answering systems based on FAQ offer numerous advantages including stability, reliability, and quality. However, given the practical limitations of scaling a manually annotated knowledge base, models often have limited recognition ability and can easily encounter bottlenecks. In order to address the problem of limited scale with FAQ datasets, this paper offers a solution at both the data level and the model level. At the data level, we use Baidu Knows to crawl relevant data and mine semantically equivalent questions, ensuring the relevance and consistency of the data. At the model level, we propose a deep neural network with transAT oriented transfer learning, which combines a transformer network and an attention network, and is suitable for semantic similarity calculations between sentence pairs. Experiments show that the proposed solution can significantly improve the impact of the model on FAQ datasets and to a certain extent resolve the issues with the limited scale of FAQ datasets.

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Research on artificial intelligence assisted decision-making algorithms for lawyers based on legal-computing theory

CHEN Liang, GUO Jia-wen, WU Jian-gong, WANG Zhan-quan, SHI Ling

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 85-99. DOI: 10.3969/j.issn.1000-5641.2019.05.007

Abstract （433）

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At present, there is a lack of intelligent decision-making tools applied to legal theory and practice. Given the characteristics of data in this field, we establish an intelligent decision-making algorithm using a variety of data analysis models. Legal-computing is focused on data-based mechanization of legal reasoning. It establishes a relationship between legal research and applications using the characteristics and data features of computer science. On this basis, the method of "implication classification" is formed, the decision tree and Naive Bayes algorithms are improved for application to the legal arena, and a coordinate system of legal relationships is established to transfer traditional legal relationship analysis into a spatial geometric system. Experimental results show that the algorithm is consistent with a lawyer's handling strategy and results, and has the feasibility of assisting lawyers more broadly in decision-making.

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Optimal route search based on user preferences

JIANG Qun, DAI Ge-nan, ZHANG Sen, GE You-ming, LIU Yu-bao

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 100-112. DOI: 10.3969/j.issn.1000-5641.2019.05.008

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This paper studies the methodology for optimal route search based on user preferences, such as keyword and weight preferences, under a constraint. The research problem is NP-hard. To solve the query efficiently, we propose two new index building methods and select candidate nodes for retrieving the established indices. This paper subsequently proposes an A^* based route search algorithm to identify the optimal route and use several effective pruning strategies to speed up execution. Experimental results on two real-world check-in datasets demonstrates the effectiveness of the proposed method. When the budget ranges from 4 hours to 7 hours, our algorithm performs better than the state-of-the-art PACER algorithm.

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Self-attention based neural networks for product titles compression

FU Yu, LI You, LIN Yu-ming, ZHOU Ya

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 113-122,167. DOI: 10.3969/j.issn.1000-5641.2019.05.009

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E-commerce product title compression has received significant attention in recent years, since it can facilitate more specific information for cross-platform knowledge alignment and multi-source data fusion. Product titles usually contain redundant descriptions, which can lead to inconsistencies. In this paper, we propose self-attention based neural networks for this task. Given the fact that self-attention mechanism networks cannot directly capture sequence features of product names, we enhance the mapping networks with a dot-attention structure, which was computed for the query and key-value pairs by a gated recurrent unit (GRU) based recurrent neural network. The proposed method improves the analytical capability of the model at a lower relative computational cost. Based on data from LESD4EC, we built two E-commerce datasets of product core phrases named LESD4EC L and LESD4EC S; we subsequently tested the model on these two datasets. A series of experiments show that the proposed model achieves better performance in product title compression than existing techniques.

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Electric energy abnormal data detection based on Isolation Forests

HUANG Fu-xing, ZHOU Guang-shan, DING Hong, ZHANG Luo-ping, QIAN Shu-yun, YUAN Pei-sen

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 123-132. DOI: 10.3969/j.issn.1000-5641.2019.05.010

Abstract （427）

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With the development of power information systems, users' requirements for the quality of power data has gradually increased. Hence, it is important to ensure the accuracy, reliability, and integrity of massive power data. In this paper, an anomaly detection algorithm based on Isolation Forests is used to realize anomaly detection of large-scale electric energy data. Isolation Forest algorithms generate random binary trees and isolated forest models by dividing training samples and detecting abnormal data points. The algorithm can not only process massive data quickly, but it also offers accurate results and a high degree of reliability. In this paper, the positive active total power (PAP) and reverse active total power (RAP) fields of large-scale electric energy data are determined. The experimental results show that the algorithm has high detection efficiency and accuracy.

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Prediction of power network stability based on an adaptive neural network

ZHAO Bo, TIAN Xiu-xia, LI Can

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 133-142. DOI: 10.3969/j.issn.1000-5641.2019.05.011

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The safety and stability of the power grid serves as the basis for reform, development, and stability of power enterprises as well as for broader society. With the increasing complexity of power grid structures, safety and stability of the power grid is important for ensuring the rapid and effective development of the national economy. In this paper, we propose an optimal neural network stability prediction model and compare performance with classical machine learning methods. By analyzing the UCI2018 grid stability simulation dataset, the experimental results show that the proposed method can achieve higher prediction accuracy and provide a new approach for research of power big data.

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Efficient data loading for log-structured data stores

DING Guo-hao, XU Chen, QIAN Wei-ning

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 143-158. DOI: 10.3969/j.issn.1000-5641.2019.05.012

Abstract （388）

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With the rapid development of Internet technology in recent years, the number of users and the data processed by Internet companies and traditional financial institutions are growing rapidly. Traditionally, businesses have tackled this scalability problem by adding servers and adopting methods based on database sharding; however, this can lead to significant manual maintenance expenses and hardware overhead. To reduce overhead and the problems caused by database sharding, businesses commonly replace heritage equipment with new database systems. In this context, new databases based on log-structured merge tree storage (such as OceanBase) are being widely used; the data blocks stored on the disks of such systems exhibit global orderly features. In the process of switching from a traditional database to a new database, a large amount of data must be transferred, and database node downtime may occur when there is extended loading. In order to reduce the total time for loading and failure recovery, we propose a data loading method that supports load balancing and efficient fault tolerance. To support balanced data loading, we pre-calculate the number of partitions based on the file size and the default block size of a target system rather than using a pre-determined number of partitions. In addition, we use the feature that the data exported from the sharding database is usually sorted to determine the split points between partitions by selecting partial sampling blocks and selecting samples in sampling blocks at equal intervals, avoiding the high overhead caused by global sampling and selecting samples randomly or at the head in sampling blocks. To speed up the recovery process, we propose a replica-based partial recovery to avoid restart-based complete reloading; this method uses the multi-replica of an LSM-tree system to reduce the amount of reloaded data. Experimental results show that by pre-calculating the number of partitions and partial sampling blocks and by using equal-interval sampling, we can accelerate data loading relative to pre-determining the number of partitions and global sampling blocks as well as relative to random or head sampling strategies. Hence, we demonstrate the efficiency of replica-based partial failure recovery compared to restart-based complete reloading.

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Implementation of LevelDB-based secondary index on two-dimensional data

LIU Zi-hao, HU Hui-qi, XU Rui, ZHOU Xuan

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 159-167. DOI: 10.3969/j.issn.1000-5641.2019.05.013

Abstract （542）

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With the growth of spatial data generated by scientific research, especially two-dimensional data and the ongoing development of NoSQL-type database technology, more and more spatial data is now stored in NoSQL databases. LevelDB is an open source Key-Value NoSQL database that is widely used because it offers excellent write performance based on LSM architecture. Given the limitations of the Key-Value structure, it is impossible to index spatial data effectively. For this problem, a LevelDB and R-treebased secondary index was proposed to support spatial two-dimensional data indexing and neighbor queries. Experimental results show that the structure has good usability.

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Implementation and optimization of a distributed consistency algorithm based on Paxos

ZHU Chao-fan, GUO Jin-wei, CAI Peng

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 168-177. DOI: 10.3969/j.issn.1000-5641.2019.05.014

Abstract （351）

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With the ongoing development of the Internet, the degree of informationization in enterprises is continuously increasing, and more and more data needs to be processed in a timely manner. In this context, the instability of network environments may lead to data loss and node downtime, which can have potentially serious consequences. Therefore, building distributed fault-tolerant storage systems is becoming increasingly popular. In order to ensure high availability and consistency across the system, a distributed consistency algorithm needs to be introduced. To improve the performance of unstable networks, traditional distributed systems based on Paxos allow for the existence of holes in the log. However, when a node enters a recovery state, these systems typically require a large amount of network interaction to complete the holes in the log; this greatly increases the time for node recovery and thereby affects system availability. To address the complexity of the node recovery process after completing a hole log, this paper proposes a redesigned log entry structure and optimized data recovery process. The effectiveness of the improved Paxos-based consistency algorithm is verified with experimental simulation.

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Implementation and optimization of GPU-based relational streaming processing systems

HUANG Hao, LI Zhi-fang, WANG Jia-lun, WENG Chu-liang

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 178-189. DOI: 10.3969/j.issn.1000-5641.2019.05.015

Abstract （332）

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State-of-the-art CPU-based streaming processing systems support complex queries on large-scale datasets. However, limited by CPU computational capability, these systems suffer from the performance tradeoff between throughput and response time, and cannot achieve the best of both. In this paper, we propose a GPU-based streaming processing system, named Serval, that co-utilizes CPU and GPU resources and efficiently processes streaming queries by micro-batching. Serval adopts the pipeline model and uses streaming execution cache to optimize throughput and response time on large scale datasets. To meet the demands of various scenarios, Serval implements multiple tuning policies by scaling the micro-batch size dynamically. Experiments show that a single-server Serval outperforms a 3-server distributed Spark Streaming by 3.87x throughput with a 91% response time on average, reflecting the efficiency of the optimization.

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Woodpecker+: Customized workload performance evaluation based on data characteristics

ZHANG Tao, ZHANG Xiao-lei, LI Yu-ming, ZHANG Chun-xi, ZHANG Rong

Journal of East China Normal University(Natural Sc 2019, 2019 (5): 190-202. DOI: 10.3969/j.issn.1000-5641.2019.05.016

Abstract （344）

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There are a number of performance testing tools, like Sysbench and OLTPBench, that can be used to benchmark the testing of database performance. However, because the standard benchmark workload is fixed and application scenarios for users are not always representative, it is impossible to accurately determine system performance. Moreover, if users are required to use a high-level programming language to implement a test workload separately for each application, this will undoubtedly introduce a substantial amount of repetitive work, resulting in inefficient testing. To address these issues, this paper designs and implements a user-defined performance test workload tool. The main benefits of this tool can be summarized as follows:It is easy to use and expandable; it provides a test definition language (TDL) for efficient construction of test cases; and it offers flexible control for mixed execution of transactions, data access distribution, lightweight and granular statistical information collection and analysis, and support for multiple mainstream DBMSs and other databases that provide database access interfaces. We highlight the tool's features through a detailed set of customized workload experiments running on the mainstream DBMS.

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Anti-periodic solutions for a class of nonlinear discrete perturbed systems

MENG Xin

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 1-6. DOI: 10.3969/j.issn.1000-5641.2019.06.001

Abstract （397）

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In this paper, anti-periodic solutions for a class of nonlinear discrete perturbed systems with exponential dichotomy are studied. By means of the Banach fixed point theorem, new sufficient conditions for the existence and uniqueness of anti-periodic solutions for nonlinear discrete perturbed systems are established. An example is given to illustrate the results we obtained.

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Identities generated from the genus theory of real quadratic fields

SHEN Li-chien

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 7-20. DOI: 10.3969/j.issn.1000-5641.2019.06.002

Abstract （367）

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Applying the genus theory of Gauss on the real quadratic fields, we derive identities involving quadratic forms and genus characters.

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Perturbation solution for a solitary wave of the nonlinear higher dimensional disturbed Klein-Gordon equation

XU Jian-zhong, MO Jia-qi

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 21-28. DOI: 10.3969/j.issn.1000-5641.2019.06.003

Abstract （381）

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In this paper, a class of nonlinear forced disturbed Klein-Gordon equations are considered using the method of generalized variational iteration. Firstly, the solitary waves of an undisturbed Klein-Gordon equation are solved using the method of undetermined coefficients for hyperbolic functions. Then, perturbed approximate solutions for a soliton of a nonlinear forced disturbed Klein-Gordon equation are obtained using the functional variational iterative principle. Finally, the uniform validity for the approximate solutions is proved. The obtained approximate solution is an analytic expression. So it can be used for carrying out analytic operations. However, these cannot be obtained via a simple simulation.

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A weighted simpler GMRES algorithm for shifted linear systems

ZHONG Hong-xiu, YANG Shu-heng

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 29-34. DOI: 10.3969/j.issn.1000-5641.2019.06.004

Abstract （365）

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Combining the strategy of weighted and simpler GMRES methods, this paper presents a weighted simpler GMRES algorithm for solving shifted linear systems, and gives some properties of the proposed algorithm. Numerical results illustrate the performance and effectiveness of the algorithm.

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Existence of solutions for a third-order two-point boundary value problem

HE Xing-yue

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 35-41,87. DOI: 10.3969/j.issn.1000-5641.2019.06.005

Abstract （361）

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Using the monotone iterative method, we demonstrate the existence of nontrivial solutions for a nonlinear third-order two-point boundary value problem by constructing two monotone iterative sequences.

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On evaluation of Bessel functions of the first kind via Prony-like methods

JI Yu, HE Yi-xuan, WU Guo-qun, WU Min

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 42-60. DOI: 10.3969/j.issn.1000-5641.2019.06.006

Abstract （402）

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Numerical approximations of Bessel functions are both of important theoretical significance and widely applied in mathematics, physics, engineering. In this work, we apply two variants of Prony's method on Bessel functions of the first kind of integer order. The Prony-like methods in cosine or sine version yield approximations as sums of sinusoidal functions of Bessel functions of the first kind of integer order. In the symbolic computation software Maple, we compute the approximations for different orders and over different intervals, and compare these approximations with those obtained through the Fourier method. Experiments show that Prony-like methods perform much better than the Fourier method.

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Novel image encryption algorithm based on self-adaptive diffusion and combined global scrambling

JIA Zhong-xiang, LIU Yin-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 61-72. DOI: 10.3969/j.issn.1000-5641.2019.06.007

Abstract （392）

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In light of the limitations and locality problems of the bit permutation process in existing bit-level encryption algorithms, a novel algorithm for self-adaptive diffusion and combined global scrambling was proposed. In the diffusion phase, the reorganization and subsequent scrambling process of bit planes is performed randomly, so that the scrambling process is not limited to just some bit planes, and we achieve the effect of global scrambling. The algorithm employed several chaotic mapping systems, allowing permutation and diffusion operations to be implemented simultaneously. To increase sensitivity to plain images and effectively resist attacks, the self-adaptive process of bit planes was added, thereby further modifying the original image data based on given rules. Simulation results demonstrate that the proposed scheme is sensitive to plain images and keys, and can resist Chosen-Plaintext Attack effectively. The cipher image has uniform pixel distribution and good image encryption.

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Algorithm for mining approximate frequent subgraphs in a single graph

DOU Jian-kai, LIN Xin, HU Wen-xin

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 73-87. DOI: 10.3969/j.issn.1000-5641.2019.06.008

Abstract （413）

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Graph mining is an important part of data mining, and significant research has been dedicated to the field. Due to the inevitability of noise during data acquisition, it is crucial to address the issue of approximation in mining frequent subgraphs. Previous work has only considered the absolute value of the graph edit distance (GED); however, the relative value between the GED and the size of the subgraph should also be considered. Hence, in this paper, we propose a novel algorithm to mine approximate frequent subgraphs in a single graph; this algortihm takes into account the size of current subgraphs for the calculation of approximations. We increase the efficiency of this algorithm by estimating the upper bound of frequent subgraphs, and pruning according to local anti-monotonicity. Experimental results show that this algorithm can find subgraphs that are missed by traditional mining algorithms, and our proposed approach is relatively efficent compared to other algorithms.

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Dynamic scheduling strategy for bicycle-sharing in cities

XIE Qing-cheng, MAO Jia-li, LIU Ting

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 88-102. DOI: 10.3969/j.issn.1000-5641.2019.06.009

Abstract （485）

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To meet the soaring demand of share bike using and improve the service efficiency of bicycle-sharing, this paper proposes a two-stage shared bicycle real-time delivery and scheduling framework based on road condition information. At the offline modeling phase, clustering is implemented on the historical short-distance taxi trajectory data using RET(Regional Extraction Technique) algorithm, to obtain the popular regions of pick-up (or drop-off), and the frequencies of the pick-up (or drop-off) at different time periods. At the online scheduling phase, a dynamic scheduling optimization model (called ROM (Real-time Optimization Model)) for bicycle-sharing is designed to obtain the popular pick-up regions in the next time period. Specifically, searching for the k-nearest neighbor bicycle drop-off regions within the current time period, and combining them with the real-time road conditions to recommend the top-k roads with convenient vehicular access for the bike dispatching car. Experiments on the taxi trajectory dataset show that the proposed method is more effective than the traditional bicycle scheduling strategies.

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A plane-based localization scheme using RGB-D sensor for the Manhattan World assumption

JIANG Yu-hao, CHEN Lei

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 103-114. DOI: 10.3969/j.issn.1000-5641.2019.06.010

Abstract （458）

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Using the Manhattan World assumption with plane-based indoor localization, an indoor positioning scheme based on plane features in RGB-D vision is proposed, which can be used to extend SLAM (Simultaneous Localization and Mapping) systems. A matching process based on the main direction of the Manhattan Frame is designed to reduce the exponentially increasing time consumed. Simplified localization with 4 degrees of freedom is adopted after the initial pose determination for the problem of low efficiency during exploration. Small subgraphs in each frame are merged into one subgraph for matching to reduce the time consumed for repetitive subgraph matching. The proposed scheme not only effectively increases the success rate of scene matching, but also simplifies positioning in unknown scenes and improves positioning efficiency. Experimental results show that the method can achieve successful localization with shorter path lengths and reduce computational cost for real-time applications.

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Experimental study on a new type of suspended filler for enhanced nitrification

HUANG Min-sheng, YANG Yin-chuan, CUI He, YANG Le, HE Yan, CAO Cheng-jin

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 115-122. DOI: 10.3969/j.issn.1000-5641.2019.06.011

Abstract （420）

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A new type of suspended filler containing zeolite powder and nitrifying bacteria was proposed in this study. The new filler was used in an enhanced nitrification model experiment of wastewater treatment plant (WWTP), in which three devices were designed with combinations of zeolite powder and nitrifying bacteria. The nitrification performance of the new suspended fillers were evaluated by monitoring changes in NH₄⁺ -N, NO₂^- -N and NO₃^- -N concentration in the three devices. The microbial community structure and diversity in the biofilm of the fillers, furthermore, were analyzed to reveal the nitrification mechanism. The results showed that compared with a single suspension filler containing only zeolite powder or nitrifying bacteria, the composite suspension filler containing zeolite powder and nitrifying bacteria had the highest average removal rate of NH₄⁺ -N (68.3%), the lowest average concentration of NO₂^- -N (12.62 mg/L), and the highest average concentration of NO₃^- -N (7.81 mg/L). Hence, the study demonstrated that the combination of zeolite powder and nitrifying bacteria can significantly improve the nitrification performance of the filler, and zeolite powder may promote the microbial nitrification process. The addition of zeolite powder in the new suspended filler was more conducive to the enrichment and growth of nitrifying bacteria, resulting in the decrease of microbial species diversity. The Nitrosomonas genus in the biofilm of the new suspension filler for enhanced nitrification has an advantage, which provides a strong guarantee for the conversion of NH₄⁺ -N in the system. The introduction of zeolite powder in the filler can further promote an increase in the proportion of the Nitrospira genus, thereby reducing the possibility of NO₂^- -N accumulation in the system. The purpose of this study was to improve the basis and parameters for the engineering application of new types of suspended fillers.

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Preference of Helice tientsinensis and Sesarma plicata for typical salt marsh plants in the north of Hangzhou Bay

LUO Bei-jing, LI Xiang, LUO Ding-hui, XU Ping, CHEN Xue-chu, YOU Wen-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 123-131. DOI: 10.3969/j.issn.1000-5641.2019.06.012

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Based on an investigation of Fengxian tidal flats, this study analyzed the feeding preference and influencing factors of two dominant crabs-Helice tientsinensis and Sesarma plicata-on typical salt marsh plants Spartina alterniflora and Phragmites australis via an indoor feeding experiment. The study provides a reference to further understanding of the control mechanisms for competition between Spartina and Phragmites. The results showed that the preference of the two crabs for different plant organs was:Leaves > Roots > Stalk. However, the preference varies across different plants; namely, Helice tientsinensis prefers Phragmites leaves, while Sesarma plicata prefers Spartina leaves. The consumption of stalk and roots of Spartina is higher than Phragmites. In addition to crab weight and species, the feeding preference is also positively correlated with the content of crude protein in plants.

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Ovipositional response of Culex pipiens pallens to common species of plants used in river ecological restoration

XIAO Bing, MA Ming-hai, HUANG Min-sheng, CHEN Qi, LENG Pei-en, HE Yan

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 132-139,152. DOI: 10.3969/j.issn.1000-5641.2019.06.013

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This study tested the ovipositional response of Cx. pipiens pallens to five species of plants and their volatiles:Acorus tatarinowii, Hydrocotyle vulgaris, Houttuynia cordata Thunb, Myriophyllum aquaticum (Vell.) Verdc. and Mentha spicata. The results showed that the oviposition activity index (OAI) value of Acorus tatarinowii was +0.58 with an effective repellency (ER) of 0%; Hence, Acorus tatarinowii can be considered as an oviposition attractant/stimulant. The OAI of Hydrocotyle vulgaris, Houttuynia cordata Thunb, and Myriophyllum aquaticum (Vell.) Verdc were measured as -0.70, -0.64 and -0.16 with an ER of 82.46%, 78.36% and 27.05%, respectively. Among these, Hydrocotyle vulgaris and Houttuynia cordata Thunb can be considered as repellents/deterrents. Meanwhile, the OAI of Mentha spicata was -1.00 with an ER of 100%, i.e., the strongest inhibiting effect, and hence considered the most suitable plant for repelling mosquitos. According to correlation analyses, there were significantly negative correlations between benzenoids and OAI values (p < 0.05). Terpenes, especially monoterpenes, had a significant positive correlation with OAI values (p < 0.05). This study provides a basis for the synergetic development of river ecological restoration and mosquito control.

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The influence of environmental factors on the settlement of Spartina alterniflora on tidal flats

ZHU Xiao-jing, YUAN Lin, ZHAO Zhi-yuan, ZHANG Li-quan, LI Wei, WEI Wei, PAN Jia-lin, CHEN Ya-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 140-152. DOI: 10.3969/j.issn.1000-5641.2019.06.014

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The invasion of the exotic plant Spartina alterniflora has caused a series of ecological risks to coastal wetland ecosystems. In order to study the influence of environmental factors on the invasion of S. alterniflora, S. alterniflora rhizomes were transplanted from land to sea on two types of tidal flats (sandy and silty)in Nanhui Dongtan, Shanghai. We monitored environmental factors such as elevation, hydrodynamic conditions, sediment characteristics, and survival rates of S. alterniflora simultaneously. Redundancy Analysis (RDA) was used to analyze the dominant factors on the settlement of S. alterniflora. The results showed that:(1) The critical shear stress, median diameter, elevation, and maximum flow velocity had dominant effects on the settlement of S. alterniflora rhizome (P<0.05). (2) The dominant environmental factors that affected S. alterniflora settlement were different on each of the tidal flat types. On the sandy flat (northern), elevation and median diameter were the dominant factors affecting S. alterniflora settlement (P<0.05). The survival rate of S. alterniflora increased with an increase in elevation and with a decrease in sediment median diameter. On the silty flat (southern), critical shear stress was the dominant factor for the settlement of S. alterniflora (P<0.05), and there was a positive correlation between critical shear stress and the survival rate of S. alterniflora. The results of the study have theoretical value and significance in guiding mechanism research, prevention, and control of S. alterniflora invasion.

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Numerical simulation of pelagic ecosystem's seasonal variation in the central East China Sea

CHEN Jian-zhong, GE Jian-zhong, BELLERBY Richard

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 153-168. DOI: 10.3969/j.issn.1000-5641.2019.06.015

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The 1D physics-ecological system model GOTM-FABM-ERSEM is used to simulate the seasonal variation in pelagic ecosystem components in the central East China Sea. The interaction between physical and bio-chemical components is well characterized. The biophysical drivers of seasonality are light, temperature, vertical stratification, and nutrient concentrations as well as their respective rates of supply. There are two blooming periods for phytoplankton:these are April and October. In summer, the seawater temperature is the highest and stratification is the strongest, with high nutrient concentrations found below the thermocline; these concentrations reach a maximum in September with phytoplankton biomass reaching a maximum of 5.3 mg C·m^-3 in the subsurface layer (about 20 m depth) and periodic growth promoted by tidal mixing. The temporal variability of zooplankton and bacteria is tightly coupled with that of phytoplankton, but with a 3 d lag in spring blooming; hence, the zooplankton and bacteria reach maximum concentrations after the spring phytoplankton bloom. Bacterial biomass in the upper layer is controlled by phytoplankton standing stock and temperatures during the summer.

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The impact of urban service facilities on house price dispersion

ZHANG Xuan-yi, SHI Run-he

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 169-178. DOI: 10.3969/j.issn.1000-5641.2019.06.016

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Due to differences in the distribution of urban service facilities, people need to pay higher prices for better services. We use the Geodetector model to explore the impact of city service facilities on house prices. The results show that:① House prices decline from the center of the city to the surrounding suburbs. ② The closer to the city center, the stronger the influence of city service facilities on house prices. ③ Traffic facilities have the greatest influence on the distribution pattern of Shanghai's housing prices. In different urban functional areas, urban service facilities have different influences on house prices. It is important to pay attention to the optimization of urban service facilities in the regulation of house prices.

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Study of factors influencing the adaptive design of household environments for the elderly

LIU Fei

Journal of East China Normal University(Natural Sc 2019, 2019 (6): 179-185. DOI: 10.3969/j.issn.1000-5641.2019.06.017

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Household environment adaptability reflects the quality of an elderly family's living conditions. The basic influencing factors of adaptive design include:social relationships, family relationships, living conditions, economic income, physical conditions, etc. Using questionnaires and subsequent data analysis, we summarize the quantitative or qualitative relationships between these respective factors. We also construct an influencing factor system that can be used as a reference for adaptive design of household environments for the elderly.

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Journal of East China Normal University(Natural Sc 2019, 2019 (6): 186-190.

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