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A free boundary problem in variational inequality with gradient constraint

GUAN Chong-hu, CHEN Jing

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 1-10. DOI: 10.3969/j.issn.1000-5641.2018.01.001

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Consider a parabolic variational inequality with gradient constraint
min{vt-1/2σ²v_xx-μv_x+cv,v_x-1}=0.
The problem stems from a stochastic optimal control problem based on optimal dividend model. By using PDE technique and the penalty method, the existence and uniqueness and some a priori estimates of the solution of the variational inequality are obtained, and then the properties of the free boundary are further discussed. It is proved that the free boundary can be expressed as a function of x with respect to t and is a monotonically increasing, C^∞ smooth curve starting from zero.

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Edge-magic even-gracefulness of several kinds of spread network models

LI Yi-chun, SUN Hui, YAO Bing

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 11-16,23. DOI: 10.3969/j.issn.1000-5641.2018.01.002

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We present a new definition, called edge-magic even-graceful labeling in this paper, and then we discover a new algorithm, called firework operation, which can add leaves with edge-magic graceful labeling and edge-magic even-graceful labeling. We spread several kinds of network models based on the complete graph K₃ and star trees and so on, and then investigate their edge-magic even-graceful properties. A connection between the edge-magic odd-graceful labeling and the edge-magic even-graceful labeling is obtained which produces network models with edge-magic graceful labeling.

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Lipschitz-likeness and contingent derivative of an implicit multifunction

WANG Li-na, FANG Zhi-miao, LI Ming-hua

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 17-23. DOI: 10.3969/j.issn.1000-5641.2018.01.003

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In this paper by introducing a key assumption, we prove that the key assumption is equivalent to the Robinson metric regularity of the implicit multifunction and that under some suitable conditions the key assumption is sufficient for the Lipschitz-likeness (metric regularity) of the implicit multifunction. Finally, we establish the specific expressions of the contingent derivative and the second-order contingent derivative for the implicit multifunction.

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A stability theorem for solutions of general time interval multidimensional BSDEs with uniformly continuous generators

DONG Yong-peng, WANG Qian-ru, MA Jiao-jiao

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 24-34,49. DOI: 10.3969/j.issn.1000-5641.2018.01.004

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The existence and uniqueness of solutions for general time interval multi-dimensional backward stochastic differential equations (BSDEs) was proved in Fan et al. (2015) under assumptions that the generator g satisfies the Osgood condition in y and the uniformly continuous condition in z both non-uniformly with respect to t, and the i-th component g_i of g depends only on(w, t, y) and the i-th row of the matrix z. In this paper, by virtue of a uniform approximation of uniformly continuous functions by a sequence of Lipschitz functions, the theorem of Girsanov, and the Bihari inequality, we establish, for the first time, a stability theorem for the solutions of the general time interval multidimensional BSDEs with uniformly continuous generators.

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The existence of time-dependent attractors for abstract evolution equations with fading memory

HU Di-di, WANG Xuan

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 35-49. DOI: 10.3969/j.issn.1000-5641.2018.01.005

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In this paper, the long-time dynamical behavior of solutions for the abstract evolution equations with fading memory is investigated on time-dependent spaces. By applying the modified pull-back attractors theory, techniques of a priori estimate and operator decomposition, we verify the asymptotic compactness of the process. Furthermore, the existence and regularity of time-dependent global attractors are proved. This paper improves some known results.

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Meromorphic solutions of some type of system of differential and difference equations

YANG Yan-yan, WEI Wen-long, HUANG Zhi-gang

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 50-58. DOI: 10.3969/j.issn.1000-5641.2018.01.006

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This article investigates some properties of meromorphic solutions of the type of system of differential-difference equations of the following form

where n ≥ 4,p₁(z)、p₂(z) are non-zero polynomials, and h₁(z),h₂(z) are entire functions. By using Nevanlinna theorem, we have obtained the solution of above equation is unique. We also discuss the conditions for several types of system of differential-difference equations if the systems of equations actually pose meromorphic solutions of finite order.

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The transition and properties from Boolean networks to discrete-time Markov chains: A case study of mice stem cell gene regulatory networks

LYU Yue, ZHANG Min, QIN Xu-dong, YAN Jia

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 59-75,90. DOI: 10.3969/j.issn.1000-5641.2018.01.007

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This paper proposes a new method based on probabilistic model checking technique to solve the problem of detecting attractors in gene regulatory networks which is vital in bio-engineering. We transform a gene regulatory network into a discrete-time Markov chains (DTMC for short) by using truth table. We verify the possibility of gene activation in some "long term" through a model checker named PRISM, which help us to find attractors of the gene regulatory network. In this paper, we show the whole procedure using the example of mice stem cell gene regulatory networks. Meanwhile, we make a new technique of detecting the promotion/inhibition relations between genes by adding gene disturbance and modifying gene activation/suppression probability. We show that in the mice regulatory network, seven genes will remain their invariable states in some "long term", then the rest of "changing" genes forms a cyclic attractor. The experiment shows that our method can find the attractors easily and directly. Moreover, our experiment successfully finds those genes affected by gene Gata1, which would be helpful for studying the mice leucopenia.

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Data cleaning on probabilistic RDF database

WANG Zhen, LIN Xin

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 76-90. DOI: 10.3969/j.issn.1000-5641.2018.01.008

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Due to the factors such as errors and noises in the process of obtaining and analyzing data, uncertain data arises in many domains, which has emerged as an important issue affecting the performance of data. Uncertain data can be stored in probabilistic databases and query facilities always yield answers with confidence. However, the accumulation and propagation of uncertainty may reduce the usability of the query results. As such, it is desirable to reduce the uncertainty of uncertain data. This paper aims at solving the problem how to promote the answers' certainty in RDF(resource description framework) graph query via crowdsourcing. The basic idea is to ask the crowd to decide whether the relationships represented by some edges are correct. In this paper, we introduce three different algorithms to select the edge which maximizes the uncertainty reduction. Finally, we verify these algorithms by experiments and show that unstable pruning algorithm and stable pruning algorithm perform better in term of efficiency.

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Forward stagewise additive modeling for entity ranking in documents

WANG Yan-hua

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 91-102,145. DOI: 10.3969/j.issn.1000-5641.2018.01.009

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Key entities of a document can help to summarize the subjects of the events or the topics that the document describes, which can contribute to applications such as entity-oriented information retrieval and question-answering. However, entities in free text are unordered and hence it is important to rank entities of a document. In this paper, firstly, we make full use of features of entities that extracted from the document and draw support from Wikipedia and Word Embedding to generate external features. Then, we propose a novel ranking model named LA-FSAM(FSAM based on AUC Metric and Logistic Function) which is based on forward stagewise algorithm additive modeling. In LA-FSAM, we employ the AUC(Area Under the Curve) metric to construct the loss function and the logistic function to integrate features of entities. Finally, the stochastic gradient descent is utilized to optimize parameters of LA-FSAM model. After experiments, our evaluation shows the efficiency of the model we proposed.

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IM²: Improved MIN/MAX window functions optimizer in relational database

SONG Guang-xuan, ZHAO Da-peng, WANG Xiao-ling

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 103-116. DOI: 10.3969/j.issn.1000-5641.2018.01.010

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Window functions, also known as analytic OLAP functions, is a part of the SQL standard, and has been extensively studied during the past decade. And the window function has more and more extensive application prospects withthegrowthofthedemandstheanalyticalapplications. Despite its simple syntax, window functions can express many complex queries, such as ranking, moving average, cumulative sum and so on. Although almost all the current mainstream commercial database support window function, the existing implementation strategy is inefficient, and is not suitable for processing big data. In this paper, we propose the IM² algorithm, an improved algorithm for the MAX/MIN window functions, which effectively improves the efficiency. And we prove the effectiveness of the IM² algorithm the theoretical complexity analysis. Additionally, we implement the algorithm in PostgreSQL and conduct extensive experiments on real world data to demonstrate the efficiency of the IM² algorithm.

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Study on the near-field effect of spherical composite antenna arrays in the radio frequency simulation system

CHENG Bo, ZHU Shou-zheng, FU Lu, BIAN Jia-jun, YU Ting-xiang, ZHU Wei-hua, WANG Li-quan, PANG Xu-dong, ZHANG Yu, LIU Chao-jie

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 117-127. DOI: 10.3969/j.issn.1000-5641.2018.01.011

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The angular accuracy of target signal is affected by the near-field effect in the radio frequency composite array. This paper presents a new method to solve the problem. The radiation electric field distribution of a three-element sub-array located on the spherical composite antenna arrays at the receiving antenna location, which is usually located in the radiating near-field region, is precisely calculated by an hybrid technique of the full-wave algorithm and uniform geometrical theory of diffraction (UTD), in the case of the three-element array surrounded with its nearby elements working at same and different frequencies. The equivalent phase center of the three-element array is then obtained by the phase gradient algorithm (PGA) based on its phase distribution. The deviation of the equivalent phase center with that derives from the amplitude gravity center equation is calculated, which is used to find the corrected input power for each element antenna of the three-element array. The simulation results for a real composite antenna array system show that the maximum angular accuracy of pitching direction is corrected from 1.50/2.37 milliradian to 0.06/0.06 milliradian on the microwave three-element antenna and millimeter wave three-element antenna.

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Beam automatic detection wire scanner system design

SHAO Zhong-wei, HAN Ding-ding, GONG Pei-rong

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 128-134,145. DOI: 10.3969/j.issn.1000-5641.2018.01.012

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A beam automatic detection wire scanner system was developed to improve the measurement resolution and shorten the data processing time. The system managed the sampling process by multi-process priority mechanism, using Allen function to amplify signal variation characterization after signal processing. Fitting range was recognized based on short time average/long time average and Akaike information criterion, and fitting parameter initial values were determined by energy gradient curve. It is found that the system detects beam accurately and improves the measurement resolution and shortens data processing time.

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CFAR target detection algorithm based on dual-censoring threshold in non-homogeneous environments

LIU Gui-ru, WANG Lu-lin, ZOU Shan

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 135-145. DOI: 10.3969/j.issn.1000-5641.2018.01.013

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In order to solve the problem that the detection performance of the radar target detector decreases badly in non-homogeneous environments. Based on the actual echo clutter distribution, a dual-censoring threshold constant false alarm rate (DCT-CFAR) detector is proposed. Dual censoring threshold is used to remove the large and small unwanted samples and real-time accurate estimate the background noise power level. Compared with the simulation and analysis results of other detectors, the proposed detector has the best detection performance and stability in multi-interfering targets, masking effect, clutter edge and other non-homogenous environments. The results show that the proposed detector still has a good detection performance in non-homogeneous environments.

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Analysis of characteristics of the cold water patch off the Jiangsu coast in summer 2016

HE Zhan-yuan, ZHANG Wen-jing, ZHU Shou-xian, CHEN Yang, ZHENG Hou-jun

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 146-153,170. DOI: 10.3969/j.issn.1000-5641.2018.01.014

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In this paper, the analysis of characteristics of a cold water patch (CWP) off the Jiangsu coast is carried out based on in-situ oceanographic observations using CTD and remote sensing data made by the Advanced Very High Resolution Radiometer (AVHRR)in the period of summer 2016 from June to Augst. Analysis of the CTD data demonstrates that relatively cold waters occurred at different depths from the sea surface to 30 m over the study region in summer 2016, with the center of the cold waters leaning to the east at deeper depth. This confirms the transportation of cold subsurface waters from the bottom of the Yellow Sea to the Jiangsu coast. The distributions of monthly averaged AVHRR Sea Surface Temperature (SST) demonstrate the existence of CWP, the radius of which varies from 67.9 km to 85.8 km, the intensity from 0.5℃ to 1.2℃, the temperature difference between the CWP center and the coast at the same latitude from 1.9℃ to 2.9℃. The daily distribution of SST indicates that there are 78 days existing CWP, among which the maximum radius is 161.8 km, the maximum intensity is 2.8℃, the maximum temperature difference is 5.9℃. The daily position of CWP center ranges in a large area, the longest distance between two adjacent days is 125.4 km. The effect of the surface wind forcing on the cold water area is also examined using a correlation analysis of the estimated radius and intensity of the CWP with surface winds, which came to a conclusion the southerly wind plays an important role in developing the CWP.

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Geomorphic characteristics of the Siming Mountain (Zhejiang, China) based on ASTER-GDEM data analysis

XU Rui, DAI Xue-rong, SHI Yu-xin, ZHENG Li-bo, HE Shan-shan

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 154-162. DOI: 10.3969/j.issn.1000-5641.2018.01.015

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Based on ASTER-GDEM data, the geomorphic characteristics of the Siming Mountain (Zhejiang, China) are analyzed using ArcGIS. Parameters describing local relief, the Swath profile and Hypsometric Integral (HI) are applied. The results show that the Siming Mountain of NE-SW is controlled by fault structures. Area occupied by mid-elevation mountain, low-elevation mountain, hill and foothill is 0.6%, 16.2%, 32.7%, and 50.5% respectively; the mid-and low-elevation mountain have a low amplitude of relief (about 81 m). Swath profile analysis shows that the top of the Siming Mountain exhibits remnants of planation surface. When the planation surface was formed, the northeast tectonic activity was resurrected, which caused the basalt to cover it. The results show that the elevation of planation surface is close to the basalt elevation, whereby the southern parts of the mountain are higher by about 300 m than the north. The Hypsometric Integral analysis of each sub-basin reveals HI values are 0-0.35, 0.35-0.45 and 0.45-0.60, accounting for 47.31%, 30.58% and 22.11%. In this paper, the geomorphological features of the study area are simply divided by the HI value. It is found that the HI values in the study area are less than 0.6, and the landforms in the mature stage are subdivided according to elevation distribution in the EP chart, which are the older stage and the typical mature stage. The rest is corresponding to the old age of the landform, which indicates that the study area is now dominated by external force denudation.

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Spatio-temporal analysis about the primary productivity of Mentougou District in Beijing from 2003 to 2014

WANG Jiu-zhong, WU Ming-quan

Journal of East China Normal University(Natural Sc 2018, 2018 (1): 163-170. DOI: 10.3969/j.issn.1000-5641.2018.01.016

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Ten years NPP products of Mentougou District from 2003 to 2014 are generated using CASA model and Landsat remote sensing data. It is used to show the spatial distribution characteristic about Mentougou District' NPP. Inter-annual variability characteristic about Mentougou District' annual amount NPP is analyzed using MODIS17A3 products from 2003 to 2014. The intra-annual variability characteristic about Mentougou District' GPP was analyzed based on MODIS17A2 product in some typical years (namely 2004, 2007, 2008, 2009, 2011, 2012). The results show that the NPP of Mentougou District has a significant spatial differentiation characteristic that the value of NPP is low on median and it is high on other region. The NPP value is very low distributed along the river valleys. The annual amount NPP has no significant increasing or decreasing trend from 2005. GPP fluctuated significantly during the year. The differences in GPP/NPP between May and September contributed the most to the differences in GPP/NPP among different years.

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Existence and non-existence of global solutions for the wave equations

JIN Shou-bo, ZHANG Zu-feng

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 1-10. DOI: 10.3969/j.issn.1000-5641.2018.02.001

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In this paper we investigated the initial boundary value problem for a class of higher order wave equations with two opposite source terms. Firstly, we introduced the latest research progress of the wave equations and defined some important generalized functionals and sets, then the properties of the functionals were discussed. Secondly, it was proved that these sets were invariant under the wave equation. Finally, we proved the existence of global weak solutions by the combination of Galerkin approximation method and potential well method, and obtained the conditions of the non-existence of global weak solutions by using the potential well method and the convexity. The optimal threshold results were given for the existence and non-existence of global weak solutions.

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Global attractors for the coupled damped suspension bridge equations with linear memory

HUANG Shang-shang, MA Qiao-zhen

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 11-22. DOI: 10.3969/j.issn.1000-5641.2018.02.002

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In this paper, we investigate the long-time dynamical behavior of coupled suspension bridge equations with linear memory. We obtain the existence of the global attractors in the weak Hilbert space by using methods of energy estimates and contractive function.

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Exploring equivalent definitions of eulerian graphs

SUN Hui, YAO Bing

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 23-30,40. DOI: 10.3969/j.issn.1000-5641.2018.02.003

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From the topic of equivalent propositions of eulerian graph to start our study, we try to dig the topology of eulerian graph, and to describe eulerian graph from the view of different insights. Finally, we obtain four new equivalent propositions of eulerian graph by the technique of "concentration" and "dilution" operations, which can be transformed into two feasible algorithms.

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Approximation properties of the left quasi-interpolants Gamma operators in Orlicz spaces

HAN Ling-xiong

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 31-40. DOI: 10.3969/j.issn.1000-5641.2018.02.004

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In order to reach better approximation degree, people start to study the quasiinterpolants of operators. In this paper, approximation properties of left quasi-interpolants Gamma operators are discussed by the tools of Ditizan-Totik modulus, K-functional, Hölder's inequality, Cauchy-Schwarz's inequality and Laguerre polynomials and so on. Then we obtain the direct, inverse and equivalence theorems which generalize the results of left quasi-interpolants Gamma operators in L_p space and improve the approximation properties of Gamma operators in Orlicz spaces.

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Efficient verifiable privacy-preserving recommendation system

SONG Chun-zhi, DONG Xiao-lei, CAO Zhen-fu

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 41-51,62. DOI: 10.3969/j.issn.1000-5641.2018.02.005

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To address the problem of privacy disclosure in traditional personalized recommendation systems, this paper proposes an efficient verifiable privacy-preserving recommendation system, which can provide user the way to verify the correctness of the resulting model of cloud computing under the premise of protecting user's data privacy. This paper uses ridge regression to find the best-fit linear curve of user's input data, and implements Yao's garbled circuit to realize the computation and the correctness verification of the recommendation model. The user and the cloud use a newly-devised privacy preserving data aggregation method named AGG (Aggregation) to replace public key homomorphic encryption used in most existing work, which can reduce the computational overhead of the user and the cloud, thus making the system more efficient. The security analysis and the efficiency analysis of the scheme are given at the end of the article.

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Balancing travel satisfaction algorithm for multi-day trip planning

XU Kan, ZHENG Jun

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 52-62. DOI: 10.3969/j.issn.1000-5641.2018.02.006

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Location-based service is a kind of service that obtains the location of mobile user and provides it according to location. Among them, one of the active topics is trip planning. People can make different trip planning to meet their multiple requirements by location-based service. However, in most studies, trip planning only focus on searching one route in many locations according to user's demands. When people are trying to visit the city more than one day, the travel satisfaction of the routes provided by previous researches would reduce by day. Hence, the previous work cannot meet the requirement of multi-day trip planning. To improve the satisfaction stability of multi-day trip planning, we use trip day as one of the multi-day travel planning parameters. We acquire points of interest (POIs) information (e.g., location, scoring, category, etc.) and construct a POI network model, obtain optimal trip routes through heuristic algorithm, develop an effective multi-day travel planning. The experimental results demonstrate that our proposed method can plan a multi-day trip with high quality and more balanced route.

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Detection of fake plate vehicles based on traffic data stream

LI Min-xi, MAO Jia-li, YUAN Pei-sen, JIN Che-qing

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 63-76,100. DOI: 10.3969/j.issn.1000-5641.2018.02.007

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Since vehicles using fake plate violate traffic laws and regulations, infringe the rights of legal license owners and harm social benefits, it is therefore of great urgency to solve this social problem. In current detection methods, unified speed threshold is used to detect fake plate vehicles. Once an inappropriate threshold was set, it would lead to misjudgements and omissions, and thereby results in a low judgement accuracy. To solve this problem, we propose a two-phase fake plate vehicles detection framework. In the offline part, we train a distributed speed model based on sparse traffic trajectory data to calculate time-dependent thresholds for different roads. In the online part, we apply a sliding-window method to monitor whether a car is an outlier. If a car is continually detected as an outlier, it will be judged as a fake, and vice versa. We then use a real dataset to evaluate our method. The results demonstrate negative influences of noise data can be avoided by our method, so the accuracy of fake plate vehicles detection can be improved significantly.

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Woodpecker: Fine-grained contention simulation database testing framework

LI Jie-ying, LI Yu-ming, ZHANG Xiao-lei, ZHANG Rong

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 77-88. DOI: 10.3969/j.issn.1000-5641.2018.02.008

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With the rich and the growing peformance requirement of applications, various database developments appear, such as row-based, column-based, main memory database and so on. Hence database testing becomes more and more important. Existing automated testing frameworks of database have some problems in flexibility of test, integrality of function and the granularity of test. Firstly they can't support functional test, performance test and DBMS functional test at the same time. Secondly popular benchmark TPC-C simulates workload contention by warehouse which can't quantify contention and maybe execution is different with expectation. Finally the use of test case is static, they can't organize and run test case dynamically. As a consequence this paper presents a flexible database testing framework which is called Woodpecker, its test task descriptive language has abundant primitives, easy-to-use and could write test case efficiently. Woodpecker is the first test framework that can mix three above-mentioned tests in one test case, and simulates workload contention in fine granularity which include read-write contention and write-write contention. We use a simple case in auto increment testing to show the descriptive language's advantage, last we verify the capacity of mixing three tests in Woodpecker, and besides, we show the results of workload contention simulation in performance test.

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Design and implementation of PK answer based on WebSocket

ZHU Xiang, DONG Qi-wen, YU Ke-ren

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 89-100. DOI: 10.3969/j.issn.1000-5641.2018.02.009

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The development of the Internet has brought great convenience to people's life and work, at the same time, people have more demand for Internet applications. How to help students answer questions onlineis increasingly becoming a reality demand for primary and secondary schools as well as online education platforms. From this realistic demand, an online PK (Player Killing) answer function is proposed. Through the online PK answer, students' interest in learning and their ability to grasp knowledgecan be enhanced.

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Electrical manipulation of Rashba spin-orbit coupling in the two-dimensional transition metal dichalcogenide

YAO Qun-fang, CAI Jia, GONG Shi-jing

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 101-108. DOI: 10.3969/j.issn.1000-5641.2018.02.010

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Using the first-principles density functional theory calculations, we investigate the Rashba spin-orbit coupling of the transition metal dichalcogenide (TMD) monolayers MX₂(M=Mo, W; X=S, Se, Te) induced by the external electric field. It is found that the anions X play an important role on the Rashba spin-orbit coupling effect. With the increase of the atomic number of X, Rashba spin-orbit splitting around the Γ point increases more distinctively, and the external electric field can hardly influence the cations because of the coverage by the anions. Thus the strength of the Rashba spin-orbit coupling follows the sequence:WTe₂ > MoTe₂ > WSe₂ > MoSe₂ > WS₂ > MoS₂. Furthermore, the distribution of the spin polarization along the high symmetry line Γ-K/K' turns from the vertical direction to the two-dimensional plane under the external electric fields, and the in-plane spin polarization distribution rises with the increase of the external electric field.

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Coherent acoustic phonon inmagnetic thin films excited by femtosecond laser

YAN Jia-qi, LI Wei, LOU Shi-tao, ZHANG Xiao-lei

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 109-114. DOI: 10.3969/j.issn.1000-5641.2018.02.011

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The interaction between the femtosecond laser pulse and the MnIr layer in the magnetic thin film excites the coherent acoustic phonon with an initial phase of 90° and a propagation velocity of 4 300 m/s. The vibration frequency of the acoustic phonon is independent of the laser energy density and is inversely proportional to the total thickness of the magnetic thin film. And the acoustic phono can propagate in the adjacent metal layers due to the high lattice matching. The electron temperature in the magnetic thin film increases sharply absorbing by femtosecond laser pulse, then an decreasing electron temperature gradient with increasing depth is generated instantaneously by the absorption of the laser which lead to the lattice oscillate coherently in the depth direction, that is, the acoustic phonon. In addition, the frequency of the acoustic phonon changes caused by the applied magnetic field is within the experimental error range, indicating that the magnetic interaction is very weak compared to the electrical interaction in the lattice.

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Luminescence characteristics of Eu²⁺-activated white-emitting phosphor prepared from solar cell cutting Si powder

YU Xin-yang, CAI Ya-guo, SUN Zhuo, PIAO Xian-qing

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 115-124. DOI: 10.3969/j.issn.1000-5641.2018.02.012

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Eu²⁺-activated white-emitting phosphors were synthesized by the process of ammonia nitridation at high temperature with the raw material of silicon powder from crystalline silicon solar cells cutting sludge. The effect of Eu²⁺ doping concentrations on structural and luminescent properties of phosphors was studied in detail. It turns out that the principal crystalline phase of the sample is the mixture of Ca₂SiO₄, CaSiO₃ and Ca₂Si₅N₈. These phosphors can be effectively excited in the range of 300~450 nm, showing intense absorption in ultraviolet to near-ultraviolet region. In addition, they exhibit intense white emissions with CIE (Commission Internationale de L'Eclairage) coordinates of (0.327 5, 0.386 6) under 370 nm excitation with color temperature of 5 705 K(5 431.85℃). There are two luminescence centers in the host, which locate at 470 nm and 570 nm, respectively. With the increase of the doping concentration of Eu²⁺, the emission reaches an intensity saturation and the optimum doping content of Eu²⁺ is 10.0 mol% due to the interaction among the activator ions which result in an concentration quenching. Using such a single phosphor, a white light output can be directly achieved combined with UV chip.

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Research progress of the target proteins by proteasome activator REGγ in human cancers

CHEN Shao-jun, LI Xiao-tao, ZHENG Jun-hua

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 125-130,159. DOI: 10.3969/j.issn.1000-5641.2018.02.013

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The proteasome activator REGγ, which is a member of REG (11 S) proteasome activator family, can stimulate the proteolytic activity of the 20 S core proteasome to degrade proteins independent of ubiquitination and ATP. In recent years, more and more studies show that REGγ is dysregulated in various human cancers and closely related to the oncogenesis and development of cancers. The potential mechanism by which REGγ exerts its role in cancer development is degradation of various target proteins. We now review the target proteins of REGγ in human cancers in order to further understand the mechanism by which REGγ exerts its role in cancer development, and to uncover the potential of REGγ to serve as a new marker for diagnosis and a novel target for treatment in human cancers.

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Studies of seasonal variation on genetic toxicity of typical fine particulate matter samples in Shanghai

ZHANG Ying, YANG Jing, CHEN Xiao-qian, YANG He-xing, YIN Hao-wen

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 131-140. DOI: 10.3969/j.issn.1000-5641.2018.02.014

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To explore the genetic toxicity on different components of PM_2.5 in Huinan and Pudong during winter and summer, the SOS chromotest is used to detect the genetic toxicity of the total particulate, the organic extract and the water-soluble component. Results shows that tests of the genetic toxicity on the total particulate in Huinan are positive at the highest concentration of 2 mg·mL^-1 both in winter and summer, also are positive in Pudong respectively at the concentration of 1 mg·mL^-1 in winter and at the highest concentration of 2 mg·mL^-1 in summer. Tests of the genetic toxicity at two stations both in winter and summer on the water-soluble component are positive at the highest concentration of 2 mg·mL^-1and negative on the the organic extract in the range of 0.000 2 mg·mL^-1and 2 mg·mL^-1. To further compare the genetic toxicity of the PM_2.5 in Huinan and Pudong during winter and summer when exposed to the same volume air, the genetic toxicity of the different components are expressed as the content of the 4-nitroquinoline oxide (4-NQO) per cubic meter of air. Results indicat that the genetic toxicity of the fine particulate matter in Shanghai Puding and Huinan is seasonal and higher in summer than in winter. Furthermore the genotoxic component and the concentration of the total particulate and the water-soluble during winter and summer may be different. It, combined with the result of existing studies that pollutants concentration or components of fine particulate matter were generally higher in winter than in summer at multiple sites in Shanghai, is speculated that the genetic toxicity of atmospheric particulates in every part of Shanghai has similar seasonal change rule. The genotoxic effect of the organic extract is not significant. The main source of the genetic toxicity in the fine particulate matter may be the water-soluble component. The atmospheric pollution at Pudong stationwas continuously serious and equivalent to Huinan stationon the pollution level and the genetic toxicity in same seasons. It is speculated that the genotoxic chemical compositions of atmospheric particulate matter at Pudong station and Huinan station are similar.

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Pollution effects of atmospheric deposition on heavy metals in leafy vegetables and its health risks

ZHOU Xiao-xiao, BI Chun-juan, WANG Meng, ZHOU Ya, CHEN Zhen-lou

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 141-150. DOI: 10.3969/j.issn.1000-5641.2018.02.015

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In order to study the pollution effects of heavy metals in atmospheric deposition on leafy vegetables and health risks via consuming vegetables, this research chooses a farmland near the suburban Shanghai as a study area, makes comparative analysis of heavy metal contents in vegetables samples, including Shanghai Green cabbage, leaf lettuce, amaranth and water spinach, both in outdoor and greenhouses, and makes the health risk assessment of the edible parts of vegetables using the target hazard quotient (THQ). The results show that the heavy metal contents of the vegetables in outdoor are higher than those in greenhouses. The average contents of Zn, Cr, Cu, Pb, Cd, Hg, and As in outdoor vegetables are 7.32, 0.91, 0.52, 0.007, 0.029, 0.002, and 0.014 mg·kg^-1, respectively; among which, the contents of Zn, Cr, Cu, Cd, and Hg are 26.4%, 28.4%, 83.3%, 33.9%, and 14% higher than those in greenhouses, respectively. The enrichment factors of greenhouse vegetables are higher than those of outdoor vegetables, showing that the heavy metals of outdoor vegetables are greatly influenced by atmospheric deposition. Different vegetables have different enrichment capacity of heavy metals. Amaranth has the strongest enrichment capacity for Zn, Hg, As and Cu; while water spinach has the most powerful enrichment capacity for Pb. TotalTarget Hazard Quotient (TTHQ)values ofvegetables in outdoor are between 1.41 to 2.99 with an average of 2.29; while those in greenhouses are between 1.10 to 2.19 with an average of 1.85, which is 23.4% lower than the outdoor values. There is a threat for the health of adult and children. The risk of consuming vegetables in outdoor is higher than that in greenhouses. Atmospheric deposition is one of the important sources of heavy metals in vegetables. Hence, we suggest to avoid outdoor cultivating vegetables in high risk areas with atmospheric pollution of heavy metals, thus reducing the impact of atmospheric deposition on enrichment of heavy metals in vegetables.

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Geochemical characteristics of the peat profile in the Yangbajing basin, Tibetan, China and its paleoenvironmental implications

MENG Qing-hao, NIU Rui, ZHENG Xiang-min, Zhou Li-min, SUN Cheng-cheng, WANG Lin

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 151-159. DOI: 10.3969/j.issn.1000-5641.2018.02.016

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The peat contains abundant information about climate change.In this study, the ratios of characteristic elements in the Yangbajing basin, Tibetan Plateau, are found to be an good indicator for evaluating the regional sedimentary environment (e.g., the change of wet and dry stages), according to the analytical results of special element rations (Fe/Mn, Ba/Sr, K₂O/Na₂O), humification and mercury (Hg) records in the peat cores. The paleoclimate evolution in the Yangbajing basin is classified as three stages as revealed by the elemental geochemical records:Temperature fluctuates and shows an overall increasing trend between 9.1~7.6 cal ka BP. The sedimentary environment is relatively wet during this period. Significant and frequent fluctuation of temperature is observed between 7.6~4.5 cal ka BP. The sedimentary environment tends to be dry; the temperature fluctuats less and shows a decreasing upward trend 4.5~3.5 cal ka BP. The sedimentary environment tends to be warm and wet. A total of four drying events are recorded in the peat profile, which occurs at approximately 5.8, 6.1, 8.2 and 8.8～8.5 cal ka BP, respectively. The four events recorded in the peat core in the Yangbajing basin are consistent with the regional and global climate records.

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Analyses of saltwater intrusion at the water intake of Qingcaosha reservoir in the Changjiang Estuary in dry season from 2015 to 2017

LI Guo-ping, ZHU Jian-rong

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 160-169. DOI: 10.3969/j.issn.1000-5641.2018.02.017

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Based on the measured salinity at the upper and lower water gate of Qingcaosha reservoir from January to Match from 2015 to 2017, and combined the measured river discharge at Datong station, wind at weather station at Chongming eastern shoal, water level at Baozhen hydrologic station and salinity at Chongxi hydrologic station, the frequency and source of saltwater intrusion at the water intake of Qingcaosha reservoir in the last three years were analyzed. The frequencies at the water intake of the reservoir from January to March in 2015, 2016 and 2017 were three, one and one of saltwater intrusion, respectively. Only one time of saltwater intrusion in the dry season of 2016 and 2017 occurred due to the higher river discharge. Among the total five times of saltwater intrusion happened at the water intake from January to March in the last three years, only one of saltwater source was from upstream, i.e., the saltwater-spilling-over from the North Branch into the South Branch, which took about 3 days for the saltwater moving from the Chongxi hydrologic station to the water intake of the reservoir; Four times of saltwater source were from downstream, i.e., the saltwater intrusion through the North Channel, which appeared in neap tide or medium tide after neap tide, was weaker under general wind speed, and was stronger under strong north wind. In view of the saltwater intrusion at the water intake of Qingcaosha reservoir in the last three years, the frequencies of saltwater intrusion coming from the downstream of the North Channel were increased distinctly, and the saltwater intrusion would be severe if strong north wind occurs in neap tide.

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Study of the ebb sediment diversion ratios during wet season in the South and North Passage, Changjiang Estuary

YANG Wan-lun, DAO Fu-hai, LUAN Hua-long, GE Jian-zhong, DING Ping-xing

Journal of East China Normal University(Natural Sc 2018, 2018 (2): 170-180. DOI: 10.3969/j.issn.1000-5641.2018.02.018

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This study investigates the characteristics of the ebb water and sediment diversion ratios during wet season in the North Passage, Changjiang Estuary and the reasons for the differences within neap-spring tidal cycles based on field measurements. The results of the measurements indicate that the averaged ebb flow diversion ratios of the North Passage in spring and neap tide are 41.9% and 43.1%, respectively, while the averaged ebb sediment diversion ratios of the North Passage in spring and neap tide are 35.1% and 39%,the averaged ebb sediment diversion ratios of the North Passage in spring can approximate representatively ebb sediment diversion status. The ebb sediment diversion ratio of the North Passage is dependent on the ratios of mean flow velocity, suspended sediment concentration and section areas of the North and South Passage. And these parameters show minor changes within neap-spring tidal cycles. Therefore, it can be concluded that the differences of ebb flow and sediment diversions of the North Passage within neap-spring tidal cycles are limited.

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A note on Kronecker's double sum and non-holomorphic Eisenstein series

SHEN Li-chien

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 1-17. DOI: 10.3969/j.issn.1000-5641.2018.03.001

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A family of non-holomorphic Eisenstein series of weight k and level N is generated from twisting of the Kronecker double series by Dirichlet characters and from which we will derive its representation in terms of the Whittaker function and the functional equation for the Eisenstein series.

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Hom-spaces for subregular nilpotent representations of sl(n+1)

LI Yi-yang, SHU Bin, YE Gang

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 18-24,45. DOI: 10.3969/j.issn.1000-5641.2018.03.002

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Let g=sl(n+1) be the special linear Lie algebra over an algebraically closed field k of prime characteristic p with p

n+1. We show that the hom-spaces between any two baby Verma modules in the same given block are always nonzero for subregular nilpotent representations of g, which reveals a complete linkage atlas for baby Verma modules.

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Irreducible sl₂-decomposition for a highest weight sl₂-module

CHAI Wei-jun, XIA Li-meng

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 25-29. DOI: 10.3969/j.issn.1000-5641.2018.03.003

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In this paper, we study the irreducible highest weight module L(Λ₀) of affine Lie algebra

. Since the three-dimensional simple algebra sl₂ is regarded as a Lie subalgebra of

, L(Λ₀) naturally becomes a sl₂-module. We present the irreducible decomposition of L(Λ₀) as a sl₂-module.

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The explicit structure of projectively flat Finsler metrics with three parameters

LIU Jin-meng, SONG Wei-dong

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 30-37. DOI: 10.3969/j.issn.1000-5641.2018.03.004

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In this paper, projectively flat Finsler metrics are considered. A class of projectively flat Finsler metrics with three parameters are formed. Moreover, the sufficient and necessary conditions for the measurement to be considered projectively flat was obtained. In particular, the flag curvature expression of projectively flat Finsler metrics are presented.

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L² harmonic 2-forms on a hypersurface in Euclidean space

ZHANG Quan-rui, LIU Jian-cheng

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 38-45. DOI: 10.3969/j.issn.1000-5641.2018.03.005

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In this paper, we study L² harmonic 2-forms on a complete hypersurface M of Euclidean space Rⁿ⁺¹(n ≥ 3). By applying the Bochner technique, we prove that if the Lⁿ(M) norms of the traceless second fundamental form Φ and the mean curvature vector H are both bounded from above by certain constants which depend only on n, then the L² harmonic 2-forms on M are parallel. Furthermore, if M is a non-minimal hypersurface, then there is no nontrivial L² harmonic 2-form on M.

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AM(s)-Convex function and its Jensen-type inequality

SONG Zhen-yun, HU Fu-gao

Journal of East China Normal University(Natural Sc 2018, 2018 (3): 46-54,120. DOI: 10.3969/j.issn.1000-5641.2018.03.006

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Based on the convexity and general convexity of a function, the authors study extending issues of a convex function. Firstly, the concept and sign of weighted r-th power s-mean of n positives are introduced; secondly, the AM(s)-convex function is defined by weighted r-th power s-mean; thirdly, the judgment theorem and operation properties of AM(s)-convex function are discussed; and finally, the Jensen-type inequality of the AM(s)-convex function is proved and an equivalent form is provided. The study shows that the AM(s)-convex function is a subset of general convex functions that includes many convex functions. Studying the AM(s)-convex function with the method of weighted r-th power s-mean is an effective way of extending and studying convex functions. This method explores a new approach to extending and studying convex functions.

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