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15 April 2018, Volume 35 Issue 2 Previous Issue    Next Issue

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Research on Container Number Correction with Low Rank Based on MSER SHEN Han-lei, XU Jie, ZOU Bin 2018, 35 (2):  123-136.  doi: 10.3969/j.issn.1005-3085.2018.02.001 Abstract ( 154 )   PDF (2396KB) ( 213 )   Save The fast record of container number is very important for the terminal and the port business. Since the image of the camera is often accompanied by the serious distortion, and greatly affect the accuracy of the character recognition algorithm, we need to correct the image before the recognition. In this paper, a fast and effective method to correct the distortion of the container image is proposed. Based on MSER element projection merging algorithm, the container area are detected and the correction feature region is determined. Then, according to low rank model with LADMAP* and initial value of warm start method, the method is able to reduce algorithm complexity and correct image. Finally, combining with the image of low rank and the convergence condition of optimization algorithm before and after the transformation, the final results are obtained. The experimental results show that the algorithm is not only good for container number correction but also robust. Related Articles | Metrics

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Several Topology Control and Invulnerability Application in Wireless Sensor Networks: An Overview WANG Yue-jiao, LIU San-yang, MA Zhong 2018, 35 (2):  137-154.  doi: 10.3969/j.issn.1005-3085.2018.02.002 Abstract ( 158 )   PDF (1245KB) ( 416 )   Save This article considers the theoretical study, simulation validation and performance analysis to make a deep overview on the topology control technology in wireless sensor networks. Topological structure automatically varies with the increasing, reduction and mobility of nodes, and topology control aims to self-organize construct global topology of connected network through the sensor nodes in order to ensure the connectivity and coverage of the network. In this article, the theoretical basis and numerical steps of four kinds of topology control algorithms are emphatically summarized. Then, two types of topological evolution algo-rithms are declaimed in detail to improve the network invulnerability, which contains an evolving model of scale-free networks and a construction of $k$ connected networks. That is, a mobile network topology model with local-area preference and a node scheduling optimization model based on $k$ connected networks are respectively proposed. Finally, we expound the prospect of topology control algorithm, introduction of mobile nodes, exploration of balanced control algorithms, application of complex network theory and combination with traditional algorithm and intelligent algorithm. Related Articles | Metrics

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Optimal Trading Strategy with Inflation under Partial Information LI Yu, FEI Wei-yin, LV Hui-ying 2018, 35 (2):  155-167.  doi: 10.3969/j.issn.1005-3085.2018.02.003 Abstract ( 127 )   PDF (227KB) ( 416 )   Save Due to the complexity of a financial market and information incompleteness, it is necessary to consider a financial market with the incomplete information. It is well-known that the inflation is an important factor which affects an investor's making-decision. This paper discusses the problem of the optimal portfolio with inflation under partial information. Firstly, by using the theory of stochastic differential equations, we establish the dynamics of stock prices. Moreover, we obtain the dynamics of consumer-basket-price by It\^o formula, and give the inflation discounted stock price dynamics equation. Secondly, the related derivation with the case of partial information is transformed to that with the case of full information by applying the nonlinear filtering method and the martingale technique. Finally, with value function of maximizing the expected utility, we derive an explicit representation of the optimal trading strategy based on the hidden Markov filtering results and Malliavin calculus, and present the numerical simulation and its economic analysis under a special case. The obtained results show that the inflation indeed has a significant effect on an investor making-decision. Related Articles | Metrics

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Bayesian Unit Root Testing for Time Series with Heavy Distribution LIU Wei-qi, HE Rui-xia 2018, 35 (2):  168-178.  doi: 10.3969/j.issn.1005-3085.2018.02.004 Abstract ( 110 )   PDF (182KB) ( 204 )   Save In this paper, based on Bayes factor and credible interval methods, we deal with the unit root test for time series with heavy distribution. Monte Carlo simulations demonstrate the validity of the Bayes factor approach and the credible interval approach in this paper. We compare and analyze these two methods. In addition, we consider the effect of prior information and degree of freedom on unit test results. At last, these two methods are applied to the time series of the unemployment rate and consumer price index in the United States, and we find that there are unit roots in these time series. Related Articles | Metrics

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Characteristic Element Free Galerkin Method for Convection-dominated Diffusion Equations TONG Xiao-hong, WANG Xing, SU Li-jun, HU Gang, QIN Xin-qiang 2018, 35 (2):  179-192.  doi: 10.3969/j.issn.1005-3085.2018.02.005 Abstract ( 140 )   PDF (527KB) ( 287 )   Save In order to eliminate the numerical oscillation caused by convection dominant of convection diffusion equation, the equation is transformed into its characteristics form firstly, and then the element free Galerkin method is proposed by using the moving least square basis functions. The convergence analysis of our method is analyzed, and two kinds of error analysis about the radius of the influence domain and time step are derived, respectively. The numerical examples are presented to discuss the comparison the new method with the finite element method as well. The numerical results show that the new method can be used to eliminate the numerical oscillation with a good convergence. Moreover, the accuracy of the new method is better than the finite element method by choosing the optimal penalty factor and dimensionless size. The new method is an effective numerical method for solving the convection-dominant diffusion equations. Related Articles | Metrics

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Existence Analysis of Positive Solutions for a Predator-prey Model with Cross-diffusion ZHANG Li-xia, LI Yan-ling, YUAN Hai-long 2018, 35 (2):  193-205.  doi: 10.3969/j.issn.1005-3085.2018.02.006 Abstract ( 144 )   PDF (693KB) ( 293 )   Save The predator-prey model with cross-diffusion is very important to describe the interaction between the species, and its dynamics behavior strongly depends on the properties of its positive solutions. In this paper, we consider the properties of positive solutions of predator-prey model with cross diffusion and Monod-Haldane type functional response function by using the principle of maximum value, local bifurcation theory and global bifurcation theory. Furthermore, one of the sufficient conditions for the existence of positive solutions is proved and the results indicate that the predator and prey can coexist under certain conditions. Related Articles | Metrics

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Infinitely Many Sign-changing Solutions for Some Fourth-order Elliptic Equations of Kirchhoff Type CHEN Jing, HAN Guo-dong 2018, 35 (2):  206-216.  doi: 10.3969/j.issn.1005-3085.2018.02.007 Abstract ( 158 )   PDF (123KB) ( 342 )   Save In engineering practice, the fourth-order elliptic equation of Kirchhoff type derives from the model of the suspension bridge. In the paper, two theorems on the existence and multiplicity of sign-changing solutions for some fourth-order elliptic equations of Kirchhoff type are proved by using the descending flow invariant set method under the assumption that the nonlinear term is odd and superquadric at infinity. The main results and the proofs are different from those in literatures. Related Articles | Metrics

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An Implementable Bundle Method for Nonsmooth Convex Optimization ZHANG Qing-ye, GAO Yan 2018, 35 (2):  217-232.  doi: 10.3969/j.issn.1005-3085.2018.02.008 Abstract ( 182 )   PDF (141KB) ( 300 )   Save An implementable bundle method for unconstrained nonsmooth convex optimization problem is provided in this paper. At first, a general bundle method is given. Next, a new update strategy for the proximal parameter is proposed. At the $k$th iteration, if the actual descent is close to the predicted one, the proximal parameter is enlarged; otherwise, it is decreased. Then, an implementable bundle method is proposed, which combines the subgradient aggregation strategy with the proximal parameter update strategy. At the same time, its convergence analysis is given as well. Finally, two numerical examples are presented to show the validity of the algorithm  proposed in this paper. Related Articles | Metrics

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An Overlapped Constant Elasticity of Substitution Production Function Model and Its Application CHENG Mao-lin 2018, 35 (2):  233-244.  doi: 10.3969/j.issn.1005-3085.2018.02.009 Abstract ( 170 )   PDF (128KB) ( 476 )   Save When analyzing economic growth factors, researchers often use a production function model, the constant elasticity of substitution production function model, to estimate and calculate the contribution rate of various influential factors to economic growth. The constant elasticity of substitution production function model takes multiple forms, and this paper puts forward a new overlapped constant elasticity of substitution production function model based on certain multivariate structural characteristics of production. This paper makes a quality assessment of the established model by assessing parameters, residual error and precision. This paper also verifies the appropriateness of the proposed model. In terms of application, this paper proposes a new scientific method to calculate the contribution rate of factors by using the overlapped constant elasticity of the substitution production function model. Finally, this paper conducts an empirical analysis of the contribution rate of relevant factors on the economic growth of China, and the results achieved were found to conform to the actual situation. The method presented in this paper may be helpful to the in-depth study of production function models. Related Articles | Metrics