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25 January 2018, Volume 2018 Issue 1 Previous Issue    Next Issue

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A free boundary problem in variational inequality with gradient constraint GUAN Chong-hu, CHEN Jing 2018, 2018 (1):  1-10.  doi: 10.3969/j.issn.1000-5641.2018.01.001 Abstract ( 507 )   HTML ( 13 )   PDF (354KB) ( 556 )   Save Consider a parabolic variational inequality with gradient constraint min{vt-1/2σ2vxx-μvx+cv,vx-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. References | Related Articles | Metrics

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Edge-magic even-gracefulness of several kinds of spread network models LI Yi-chun, SUN Hui, YAO Bing 2018, 2018 (1):  11-16,23.  doi: 10.3969/j.issn.1000-5641.2018.01.002 Abstract ( 473 )   HTML ( 70 )   PDF (590KB) ( 578 )   Save 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. References | Related Articles | Metrics

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Lipschitz-likeness and contingent derivative of an implicit multifunction WANG Li-na, FANG Zhi-miao, LI Ming-hua 2018, 2018 (1):  17-23.  doi: 10.3969/j.issn.1000-5641.2018.01.003 Abstract ( 475 )   HTML ( 16 )   PDF (264KB) ( 590 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  24-34,49.  doi: 10.3969/j.issn.1000-5641.2018.01.004 Abstract ( 416 )   HTML ( 10 )   PDF (455KB) ( 648 )   Save 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 gi 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. References | Related Articles | Metrics

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The existence of time-dependent attractors for abstract evolution equations with fading memory HU Di-di, WANG Xuan 2018, 2018 (1):  35-49.  doi: 10.3969/j.issn.1000-5641.2018.01.005 Abstract ( 453 )   HTML ( 18 )   PDF (285KB) ( 662 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  50-58.  doi: 10.3969/j.issn.1000-5641.2018.01.006 Abstract ( 495 )   HTML ( 10 )   PDF (270KB) ( 608 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  59-75,90.  doi: 10.3969/j.issn.1000-5641.2018.01.007 Abstract ( 512 )   HTML ( 10 )   PDF (956KB) ( 589 )   Save 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. References | Related Articles | Metrics

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Data cleaning on probabilistic RDF database WANG Zhen, LIN Xin 2018, 2018 (1):  76-90.  doi: 10.3969/j.issn.1000-5641.2018.01.008 Abstract ( 352 )   HTML ( 10 )   PDF (702KB) ( 545 )   Save 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. References | Related Articles | Metrics

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Forward stagewise additive modeling for entity ranking in documents WANG Yan-hua 2018, 2018 (1):  91-102,145.  doi: 10.3969/j.issn.1000-5641.2018.01.009 Abstract ( 483 )   HTML ( 11 )   PDF (576KB) ( 607 )   Save 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. References | Related Articles | Metrics

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IM2: Improved MIN/MAX window functions optimizer in relational database SONG Guang-xuan, ZHAO Da-peng, WANG Xiao-ling 2018, 2018 (1):  103-116.  doi: 10.3969/j.issn.1000-5641.2018.01.010 Abstract ( 530 )   HTML ( 10 )   PDF (700KB) ( 671 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  117-127.  doi: 10.3969/j.issn.1000-5641.2018.01.011 Abstract ( 478 )   HTML ( 9 )   PDF (731KB) ( 677 )   Save 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. References | Related Articles | Metrics

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Beam automatic detection wire scanner system design SHAO Zhong-wei, HAN Ding-ding, GONG Pei-rong 2018, 2018 (1):  128-134,145.  doi: 10.3969/j.issn.1000-5641.2018.01.012 Abstract ( 412 )   HTML ( 8 )   PDF (841KB) ( 563 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  135-145.  doi: 10.3969/j.issn.1000-5641.2018.01.013 Abstract ( 522 )   HTML ( 60 )   PDF (692KB) ( 756 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  146-153,170.  doi: 10.3969/j.issn.1000-5641.2018.01.014 Abstract ( 454 )   HTML ( 8 )   PDF (728KB) ( 632 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  154-162.  doi: 10.3969/j.issn.1000-5641.2018.01.015 Abstract ( 608 )   HTML ( 9 )   PDF (3017KB) ( 620 )   Save 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. References | Related Articles | Metrics

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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 2018, 2018 (1):  163-170.  doi: 10.3969/j.issn.1000-5641.2018.01.016 Abstract ( 440 )   HTML ( 10 )   PDF (797KB) ( 753 )   Save 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. References | Related Articles | Metrics