Journal of Applied Mathematics http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Localizing Brain Activity from Multiple Distinct Sources via EEG Sun, 23 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/232747/ An important question arousing in the framework of electroencephalography (EEG) is the possibility to recognize, by means of a recorded surface potential, the number of activated areas in the brain. In the present paper, employing a homogeneous spherical conductor serving as an approximation of the brain, we provide a criterion which determines whether the measured surface potential is evoked by a single or multiple localized neuronal excitations. We show that the uniqueness of the inverse problem for a single dipole is closely connected with attaining certain relations connecting the measured data. Further, we present the necessary and sufficient conditions which decide whether the collected data originates from a single dipole or from numerous dipoles. In the case where the EEG data arouses from multiple parallel dipoles, an isolation of the source is, in general, not possible. George Dassios, Michael Doschoris, and Konstantia Satrazemi Copyright © 2014 George Dassios et al. All rights reserved. Extension of Khan’s Homotopy Transformation Method via Optimal Parameter for Differential Difference Equations Sun, 23 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/813474/ A new scheme, deduced from Khan’s homotopy perturbation transform method (HPTM) (Khan, 2014; Khan and Wu, 2011) via optimal parameter, is presented for solving nonlinear differential difference equations. Simple but typical examples are given to illustrate the validity and great potential of Khan’s homotopy perturbation transform method (HPTM) via optimal parameter in solving nonlinear differential difference equation. The numerical solutions show that the proposed method is very efficient and computationally attractive. It provides more realistic series solutions that converge very rapidly for nonlinear real physical problems. The results reveal that the method is very effective and simple. This method gives more reliable results as compared to other existing methods available in the literature. The numerical results demonstrate the validity and applicability of the method. Mohamed S. Mohamed, Khaled A. Gepreel, Faisal A. Al-Malki, and Nouf Altalhi Copyright © 2014 Mohamed S. Mohamed et al. All rights reserved. Invariant Surfaces under Hyperbolic Translations in Hyperbolic Space Thu, 20 Nov 2014 12:27:04 +0000 http://www.hindawi.com/journals/jam/2014/838564/ We consider hyperbolic rotation (), hyperbolic translation (), and horocyclic rotation () groups in , which is called Minkowski model of hyperbolic space. Then, we investigate extrinsic differential geometry of invariant surfaces under subgroups of in . Also, we give explicit parametrization of these invariant surfaces with respect to constant hyperbolic curvature of profile curves. Finally, we obtain some corollaries for flat and minimal invariant surfaces which are associated with de Sitter and hyperbolic shape operator in . Mahmut Mak and Baki Karlığa Copyright © 2014 Mahmut Mak and Baki Karlığa. All rights reserved. Design Mode Analysis of Pareto Solution Set for Decision-Making Support Thu, 20 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/520209/ Decision making in engineering design problems is challenging because they have multiple and conflicting criteria and complex correlation between design parameters. This study proposes a decision-making support methodology named design mode analysis, which consists of data clustering and principal component analysis (PCA). A design mode is indicated by the eigenvector obtained by PCA and reveals the dominant design parameters in a given dataset. The proposed method is a general framework to obtain the design modes from high-dimensional and large datasets. The effectiveness of the proposed method is verified on the conceptual design problem of the hybrid rocket engine. Satoru Hiwa, Tomoyuki Hiroyasu, and Mitsunori Miki Copyright © 2014 Satoru Hiwa et al. All rights reserved. Pricing Parisian Option under a Stochastic Volatility Model Wed, 19 Nov 2014 10:12:32 +0000 http://www.hindawi.com/journals/jam/2014/956454/ We study the pricing of a Parisian option under a stochastic volatility model. Based on the manipulation problem that barrier options might create near barriers, the Parisian option has been designed as an extended barrier option. A stochastic volatility correction to the Black-Scholes price of the Parisian option is obtained in a partial differential equation form and the solution is characterized numerically. Min-Ku Lee and Kyu-Hwan Jang Copyright © 2014 Min-Ku Lee and Kyu-Hwan Jang. All rights reserved. Linearization from Complex Lie Point Transformations Wed, 19 Nov 2014 08:54:59 +0000 http://www.hindawi.com/journals/jam/2014/793247/ Complex Lie point transformations are used to linearize a class of systems of second order ordinary differential equations (ODEs) which have Lie algebras of maximum dimension , with . We identify such a class by employing complex structure on the manifold that defines the geometry of differential equations. Furthermore we provide a geometrical construction of the procedure adopted that provides an analogue in of the linearizability criteria in . Sajid Ali, M. Safdar, and Asghar Qadir Copyright © 2014 Sajid Ali et al. All rights reserved. Performance Modeling of Proposed GUISET Middleware for Mobile Healthcare Services in E-Marketplaces Tue, 18 Nov 2014 13:48:05 +0000 http://www.hindawi.com/journals/jam/2014/248293/ GUISET is a proposed middleware engine currently under study in South Africa. The goal is to provide utility services for small, medium, and macroenterprises in the context of mobile e-services. Three things are important to make this engine effective and efficient: the implementation, performance, and the pricing strategy. The literature has delved richly into implementation issue of similar projects. Both the performance and the pricing strategy issues have not been fully discussed especially in the context of mobile healthcare services. Some literature has addressed the performance issue using the exogenous nonpriority and the preemptive model. However, with providers offering different services using that approach may prove to be difficult to implement. This work extends existing and widely adopted theories to non-preemptive model by using the queuing theory and the simulation model in the context of mobile healthcare services. Our evaluation is based on non-preemptive priority and nonpriority discipline. Our results reveal that the unconditional average waiting time remains the same with reduction in waiting time over the non-preemptive priority model in four out of the five classes observed. This is envisaged to be beneficial in mobile healthcare services where events are prioritized and urgent attention is needed to be given to urgent events. Alaba Olu Akingbesote, Mathew Olusegun Adigun, Sibisuso Xulu, and Edgar Jembere Copyright © 2014 Alaba Olu Akingbesote et al. All rights reserved. Existence Results for a Coupled System of Nonlinear Fractional Differential Equations in Banach Spaces Tue, 18 Nov 2014 08:51:46 +0000 http://www.hindawi.com/journals/jam/2014/463148/ We investigate boundary value problems for a coupled system of nonlinear fractional differential equations involving Caputo derivative in Banach spaces. A generalized singular type coupled Gronwall inequality system is given to obtain an important a priori bound. Existence results are obtained by using fixed point theorems and an example is given to illustrate the results. Yuping Cao and Chuanzhi Bai Copyright © 2014 Yuping Cao and Chuanzhi Bai. All rights reserved. The Exact Endoscopic Effect on the Peristaltic Flow of a Nanofluid Tue, 18 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/367526/ The problem of the peristaltic flow of a nanofluid under the effect of an endoscope is reinvestigated. The mathematical model is governed by a system of linear and nonlinear partial differential equations with prescribed boundary conditions. Really, the exact solution for any physical problem, if available, is of great importance which inevitably leads to a better understanding of the behaviour of the involved physical phenomena. An attempt for doing so has been done in the present paper, where the temperature equation is solved exactly by the help of Laplace transform and, accordingly, the exact expressions for the nanoparticle concentration, the axial velocity, the pressure gradient, and the pressure rise are established. Furthermore, it is showed in this paper that the physical interpretations of some involved phenomena are found totally different than those previously obtained by the approximate solutions using the homotopy perturbation method. In addition, several comparisons between the current results and the approximate ones have been displayed. Finally, the effect of various parameters on the temperature distribution, the nanoparticle concentration, the pressure gradient, and the pressure rise has been also discussed through graphs. S. M. Khaled, Abdelhalim Ebaid, and Fahd Al Mutairi Copyright © 2014 S. M. Khaled et al. All rights reserved. Modelling Shallow Water Wakes Using a Hybrid Turbulence Model Mon, 17 Nov 2014 11:52:38 +0000 http://www.hindawi.com/journals/jam/2014/714031/ A numerical research with different turbulence models for shallow water equations was carried out. This was done in order to investigate which model has the ability to reproduce more accurately the wakes produced by the shock of the water hitting a submerged island inside a canal. The study of this phenomenon is important for the numerical methods application advancement in the simulation of free surface flows since these models involve a number of simplifications and assumptions that can have a significant impact on the numerical solutions quality and thus can not reproduce correctly the physical phenomenon. The numerical experiments were carried out on an experimental case under controlled conditions, consisting of a channel with a submerged conical island. The numerical scheme is based on the Eulerian-Lagrangian finite volume method with four turbulence models, three mixing lengths (ml), and one joining on the horizontal axis with a mixing-length model (ml) on the vertical axis. The experimental results show that a with ml turbulence model makes it possible to approach the experimental results in a more qualitative manner. We found that when using only a model in the vertical and horizontal direction, the numerical results overestimate the experimental data. Additionally the computing time is reduced by simplifying the turbulence model. Clemente Rodriguez-Cuevas, Carlos Couder-Castañeda, Esteban Flores-Mendez, Israel Enrique Herrera-Díaz, and Rodolfo Cisneros-Almazan Copyright © 2014 Clemente Rodriguez-Cuevas et al. All rights reserved. A Joint Doppler Frequency Shift and DOA Estimation Algorithm Based on Sparse Representations for Colocated TDM-MIMO Radar Sun, 16 Nov 2014 11:11:34 +0000 http://www.hindawi.com/journals/jam/2014/421391/ We address the problem of a new joint Doppler frequency shift (DFS) and direction of arrival (DOA) estimation for colocated TDM-MIMO radar that is a novel technology applied to autocruise and safety driving system in recent years. The signal model of colocated TDM-MIMO radar with few transmitter or receiver channels is depicted and “time varying steering vector” model is proved. Inspired by sparse representations theory, we present a new processing scheme for joint DFS and DOA estimation based on the new input signal model of colocated TDM-MIMO radar. An ultracomplete redundancy dictionary for angle-frequency space is founded in order to complete sparse representations of the input signal. The SVD-SR algorithm which stands for joint estimation based on sparse representations using SVD decomposition with OMP algorithm and the improved M-FOCUSS algorithm which combines the classical M-FOCUSS with joint sparse recovery spectrum are applied to the new signal model’s calculation to solve the multiple measurement vectors (MMV) problem. The improved M-FOCUSS algorithm can work more robust than SVD-SR and JS-SR algorithms in the aspects of coherent signals resolution and estimation accuracy. Finally, simulation experiments have shown that the proposed algorithms and schemes are feasible and can be further applied to practical application. Tao Chen, Huanxin Wu, and Lutao Liu Copyright © 2014 Tao Chen et al. All rights reserved. Horseshoe Chaos in a Simple Memristive Circuit Sun, 16 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/546091/ A simple memristive circuit model is revisited and the stability analysis is to be given. Furthermore, we resort to Poincaré section and Poincaré map technique and present rigorous computer-assisted verification of horseshoe chaos by virtue of topological horseshoe theory. Lei Wang, XiaoSong Yang, WenJie Hu, and Quan Yuan Copyright © 2014 Lei Wang et al. All rights reserved. HSV-2 and Substance Abuse amongst Adolescents: Insights through Mathematical Modelling Thu, 13 Nov 2014 13:24:45 +0000 http://www.hindawi.com/journals/jam/2014/104819/ Herpes simplex virus infection is mostly spread and occurs more commonly among substance abusing adolescents as compared to the nonsubstance abusing. In this paper, a mathematical model for the spread of HSV-2 within a community with substance abusing adolescents is developed and analysed. The impacts of condom use and educational campaigns are examined. The study suggests that condom use is highly effective among adolescents, when we have more of them quitting than becoming substance abusers. Measures such as educational campaigns can be put in place to try and reduce adolescents from becoming substance abusers. Further, we applied optimal control theory to the proposed model. The controls represent condom use and educational campaigns. The objective is based on maximising the susceptible nonsubstance abusing adolescents, while minimising the susceptible substance abusing adolescents, the infectious nonsubstance abusing adolescents, and the infectious substance abusing adolescents. We used Pontrygin’s maximum principle to characterise the optimal levels of the two controls. The resulting optimality system is solved numerically. Overall, the application of the optimal control theory suggests that more effort should be devoted to condom use as compared to educational campaigns. A. Mhlanga, C. P. Bhunu, and S. Mushayabasa Copyright © 2014 A. Mhlanga et al. All rights reserved. An Extension of the MULTIMOORA Method for Multiple Criteria Group Decision Making Based upon Hesitant Fuzzy Sets Wed, 12 Nov 2014 12:55:15 +0000 http://www.hindawi.com/journals/jam/2014/527836/ In order to determine the membership of an element to a set owing to ambiguity between a few different values, the hesitant fuzzy set (HFS) has been proposed and widely diffused to deal with vagueness and uncertainty involved in the process of multiple criteria group decision making (MCGDM) problems. In this paper, we develop novel definitions of score function and distance measure for HFSs. Some examples are given to illustrate that the proposed definitions are more reasonable than the traditional ones. Furthermore, our study extends the MULTIMOORA (Multiple Objective Optimization on the basis of Ratio Analysis plus Full Multiplicative Form) method with HFSs. The proposed method thus provides the means for multiple criteria decision making (MCDM) regarding uncertain assessments. Utilization of hesitant fuzzy power aggregation operators also enables facilitating the process of MCGDM. A numerical example of software selection demonstrates the possibilities of application of the proposed method. Zhi-Hui Li Copyright © 2014 Zhi-Hui Li. All rights reserved. Spectral Method for Solving the Nonlinear Thomas-Fermi Equation Based on Exponential Functions Wed, 12 Nov 2014 10:23:35 +0000 http://www.hindawi.com/journals/jam/2014/168568/ We present an efficient spectral methods solver for the Thomas-Fermi equation for neutral atoms in a semi-infinite domain. The ordinary differential equation has been solved by applying a spectral method using an exponential basis set. One of the main advantages of this approach, when compared to other relevant applications of spectral methods, is that the underlying integrals can be solved analytically and numerical integration can be avoided. The nonlinear algebraic system of equations that is derived using this method is solved using a minimization approach. The presented method has shown robustness in the sense that it can find high precision solution for a wide range of parameters that define the basis set. In our test, we show that the new approach can achieve a very high rate of convergence using a small number of bases elements. We also present a comparison of recently published results for this problem using spectral methods based on several different basis sets. The comparison shows that our method is highly competitive and in many aspects outperforms the previous work. Raka Jovanovic, Sabre Kais, and Fahhad H. Alharbi Copyright © 2014 Raka Jovanovic et al. All rights reserved. An Evaluation Model for Tailings Storage Facilities Using Improved Neural Networks and Fuzzy Mathematics Wed, 12 Nov 2014 10:11:59 +0000 http://www.hindawi.com/journals/jam/2014/328902/ With the development of mine industry, tailings storage facility (TSF), as the important facility of mining, has attracted increasing attention for its safety problems. However, the problems of low accuracy and slow operation rate often occur in current TSF safety evaluation models. This paper establishes a reasonable TSF safety evaluation index system and puts forward a new TSF safety evaluation model by combining the theories for the analytic hierarchy process (AHP) and improved back-propagation (BP) neural network algorithm. The varying proportions of cross validation were calculated, demonstrating that this method has better evaluation performance with higher learning efficiency and faster convergence speed and avoids the oscillation in the training process in traditional BP neural network method and other primary neural network methods. The entire analysis shows the combination of the two methods increases the accuracy and reliability of the safety evaluation, and it can be well applied in the TSF safety evaluation. Sen Tian and Jianhong Chen Copyright © 2014 Sen Tian and Jianhong Chen. All rights reserved. Nonlinear Control of an Active Magnetic Bearing System Achieved Using a Fuzzy Control with Radial Basis Function Neural Network Wed, 12 Nov 2014 09:56:22 +0000 http://www.hindawi.com/journals/jam/2014/272391/ Studies on active magnetic bearing (AMB) systems are increasing in popularity and practical applications. Magnetic bearings cause less noise, friction, and vibration than the conventional mechanical bearings; however, the control of AMB systems requires further investigation. The magnetic force has a highly nonlinear relation to the control current and the air gap. This paper proposes an intelligent control method for positioning an AMB system that uses a neural fuzzy controller (NFC). The mathematical model of an AMB system comprises identification followed by collection of information from this system. A fuzzy logic controller (FLC), the parameters of which are adjusted using a radial basis function neural network (RBFNN), is applied to the unbalanced vibration in an AMB system. The AMB system exhibited a satisfactory control performance, with low overshoot, and produced improved transient and steady-state responses under various operating conditions. The NFC has been verified on a prototype AMB system. The proposed controller can be feasibly applied to AMB systems exposed to various external disturbances; demonstrating the effectiveness of the NFC with self-learning and self-improving capacities is proven. Seng-Chi Chen, Van-Sum Nguyen, Dinh-Kha Le, and Nguyen Thi Hoai Nam Copyright © 2014 Seng-Chi Chen et al. All rights reserved. New Inequalities for Gamma and Digamma Functions Wed, 12 Nov 2014 09:44:32 +0000 http://www.hindawi.com/journals/jam/2014/264652/ By using the mean value theorem and logarithmic convexity, we obtain some new inequalities for gamma and digamma functions. M. R. Farhangdoost and M. Kargar Dolatabadi Copyright © 2014 M. R. Farhangdoost and M. Kargar Dolatabadi. All rights reserved. Statistical Approximation of -Bernstein-Schurer-Stancu-Kantorovich Operators Wed, 12 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jam/2014/569450/ We introduce two kinds of Kantorovich-type q-Bernstein-Schurer-Stancu operators. We first estimate moments of q-Bernstein-Schurer-Stancu-Kantorovich operators. We also establish the statistical approximation properties of these operators. Furthermore, we study the rates of statistical convergence of these operators by means of modulus of continuity and the functions of Lipschitz class. Qiu Lin Copyright © 2014 Qiu Lin. All rights reserved. Trigonometric Regression for Analysis of Public Health Surveillance Data Tue, 11 Nov 2014 12:27:57 +0000 http://www.hindawi.com/journals/jam/2014/673293/ Statistical challenges in monitoring modern biosurveillance data are well described in the literature. Even though assumptions of normality, independence, and stationarity are typically violated in the biosurveillance data, statistical process control (SPC) charts adopted from industry have been widely used in public health for communicable disease monitoring. But, blind usage of SPC charts in public health that ignores the characteristics of disease surveillance data may result in poor detection of disease outbreaks and/or excessive false-positive alarms. Thus, improved biosurveillance systems are clearly needed, and participation of statisticians knowledgeable in SPC alongside epidemiologists in the design and evaluation of such systems can be more productive. We describe and study a method for monitoring reportable disease counts using a Poisson distribution whose mean is allowed to vary depending on the week of the year. The seasonality is modeled by a trigonometric function whose parameters can be estimated by some baseline set of data. We study the ability of such a model to detect an outbreak. Specifically, we estimate the probability of detection (POD), the average number of weeks to signal given that a signal has occurred (conditional expected delay, or CED), and the false-positive rate (FPR, the average number of false-alarms per year). Steven E. Rigdon, George Turabelidze, and Ehsan Jahanpour Copyright © 2014 Steven E. Rigdon et al. All rights reserved. Spread and Control of Mobile Benign Worm Based on Two-Stage Repairing Mechanism Mon, 10 Nov 2014 12:40:12 +0000 http://www.hindawi.com/journals/jam/2014/746803/ Both in traditional social network and in mobile network environment, the worm is a serious threat, and this threat is growing all the time. Mobile smartphones generally promote the development of mobile network. The traditional antivirus technologies have become powerless when facing mobile networks. The development of benign worms, especially active benign worms and passive benign worms, has become a new network security measure. In this paper, we focused on the spread of worm in mobile environment and proposed the benign worm control and repair mechanism. The control process of mobile benign worms is divided into two stages: the first stage is rapid repair control, which uses active benign worm to deal with malicious worm in the mobile network; when the network is relatively stable, it enters the second stage of postrepair and uses passive mode to optimize the environment for the purpose of controlling the mobile network. Considering whether the existence of benign worm, we simplified the model and analyzed the four situations. Finally, we use simulation to verify the model. This control mechanism for benign worm propagation is of guiding significance to control the network security. Meng Wang, Zhide Chen, Li Xu, and Huan Zhan Copyright © 2014 Meng Wang et al. All rights reserved. On Minimum Wiener Polarity Index of Unicyclic Graphs with Prescribed Maximum Degree Sun, 09 Nov 2014 11:35:55 +0000 http://www.hindawi.com/journals/jam/2014/316108/ The Wiener polarity index of a connected graph is defined as the number of its pairs of vertices that are at distance three. By introducing some graph transformations, in different way with that of Huang et al., 2013, we determine the minimum Wiener polarity index of unicyclic graphs with any given maximum degree and girth, and characterize extremal graphs. These observations lead to the determination of the minimum Wiener polarity index of unicyclic graphs and the characterization of the extremal graphs. Jianping Ou, Xing Feng, and Saihua Liu Copyright © 2014 Jianping Ou et al. All rights reserved. Iterative Methods for Nonlinear Equations or Systems and Their Applications 2014 Sun, 09 Nov 2014 10:48:17 +0000 http://www.hindawi.com/journals/jam/2014/293263/ Juan R. Torregrosa, Ioannis K. Argyros, Changbum Chun, Alicia Cordero, and Fazlollah Soleymani Copyright © 2014 Juan R. Torregrosa et al. All rights reserved. Modified Reduced Differential Transform Method for Partial Differential-Algebraic Equations Thu, 06 Nov 2014 08:00:24 +0000 http://www.hindawi.com/journals/jam/2014/279481/ This work presents the application of the reduced differential transform method (RDTM) to find solutions of partial differential-algebraic equations (PDAEs). Two systems of index-two and index-three are solved to show that RDTM can provide analytical solutions for PDAEs in convergent series form. In addition, we present the posttreatment of the power series solutions with the Laplace-Padé resummation method as a useful technique to find exact solutions. The main advantage of the proposed technique is that it is based on a few straightforward steps and does not generate secular terms or depend on a perturbation parameter. Brahim Benhammouda, Hector Vazquez-Leal, and Arturo Sarmiento-Reyes Copyright © 2014 Brahim Benhammouda et al. All rights reserved. Optimization Method for Crop Growth Characteristics Based on Improved Locality Preserving Projection Wed, 05 Nov 2014 10:20:26 +0000 http://www.hindawi.com/journals/jam/2014/809597/ Locality preserving projection (LPP) retains only partial information, and category information of samples is not considered, which causes misclassification of feature extraction. An improved locality preserving projection algorithm is proposed to optimize the extraction of growth characteristics. Firstly, preliminary dimensionality reduction of sample data is constructed by using two-dimensional principal component analysis (2DPCA) to retain the spatial information. Then, two optimized subgraphs are defined to describe the neighborhood relation between different categories of data. Finally, feature parameters set are obtained to extract local information of samples by improved LPP algorithm. The experiments show that the improved LPP algorithm has good adaptability, and the highest SVM classification accuracy rate of this method can reach more than 96%. Compared with other methods, the improved LPP has superior optimized performance in terms of multidimensional data analysis and optimization. Jia Dongyao, Hu Po, and Zou Shengxiong Copyright © 2014 Jia Dongyao et al. All rights reserved. Adaptive Fuzzy Fault-Tolerant Output Feedback Tracking Control of Uncertain Stochastic Nonlinear Systems with Unknown Time-Delay and Tracking Error Constrained Wed, 05 Nov 2014 05:52:24 +0000 http://www.hindawi.com/journals/jam/2014/703609/ The problem of tracking error constrained adaptive fuzzy output feedback control is investigated for a class of single-input and single-output (SISO) stochastic nonlinear systems with actuator faults, unknown time-delay, and unmeasured states. The considered faults are modeled as both loss of effectiveness and lock-in-place. The fuzzy logic systems are used to approximate the unknown nonlinear functions, and a fuzzy adaptive observer is designed for estimating the unmeasured states. By transforming the tracking errors into new virtual error variables and based on backstepping recursive design technique, a new fuzzy adaptive output feedback control method is developed. It is shown that all the signals of the resulting closed-loop system are bounded in probability and the tracking error remains an adjustable neighborhood of the origin within the prescribed bounds. The simulation results are provided to show the effectiveness of the proposed approach. Shuai Sui, Shaocheng Tong, and Yongming Li Copyright © 2014 Shuai Sui et al. All rights reserved. Robust Mean Change-Point Detecting through Laplace Linear Regression Using EM Algorithm Tue, 04 Nov 2014 13:14:07 +0000 http://www.hindawi.com/journals/jam/2014/856350/ We proposed a robust mean change-point estimation algorithm in linear regression with the assumption that the errors follow the Laplace distribution. By representing the Laplace distribution as an appropriate scale mixture of normal distribution, we developed the expectation maximization (EM) algorithm to estimate the position of mean change-point. We investigated the performance of the algorithm through different simulations, finding that our methods is robust to the distributions of errors and is effective to estimate the position of mean change-point. Finally, we applied our method to the classical Holbert data and detected a change-point. Fengkai Yang Copyright © 2014 Fengkai Yang. All rights reserved. Parameters Investigation of Mathematical Model of Productivity for Automated Line with Availability by DMAIC Methodology Mon, 03 Nov 2014 06:43:46 +0000 http://www.hindawi.com/journals/jam/2014/206717/ Automated line is widely applied in industry especially for mass production with less variety product. Productivity is one of the important criteria in automated line as well as industry which directly present the outputs and profits. Forecast of productivity in industry accurately in order to achieve the customer demand and the forecast result is calculated by using mathematical model. Mathematical model of productivity with availability for automated line has been introduced to express the productivity in terms of single level of reliability for stations and mechanisms. Since this mathematical model of productivity with availability cannot achieve close enough productivity compared to actual one due to lack of parameters consideration, the enhancement of mathematical model is required to consider and add the loss parameters that is not considered in current model. This paper presents the investigation parameters of productivity losses investigated by using DMAIC (Define, Measure, Analyze, Improve, and Control) concept and PACE Prioritization Matrix (Priority, Action, Consider, and Eliminate). The investigated parameters are important for further improvement of mathematical model of productivity with availability to develop robust mathematical model of productivity in automated line. Tan Chan Sin, Ryspek Usubamatov, Mohd Fidzwan B. Md. Amin Hamzas, Low Kin Wai, Teh Keat Yao, and Muhammad Syahril Bahari Copyright © 2014 Tan Chan Sin et al. All rights reserved. Effects of Exchanging Battery on the Electric Vehicle’s Electricity Consumption in a Single-Lane Traffic System Thu, 30 Oct 2014 09:21:01 +0000 http://www.hindawi.com/journals/jam/2014/435765/ We propose a car-following model to explore the influences of exchanging battery on each vehicle’s electricity consumption under three traffic situations from the numerical perspective. The numerical results show that exchanging battery will destroy the stability of traffic flow, but the effects are related to each vehicle’s initial headway, the time that each electric vehicle exchanges the battery, the proportion of the electric vehicles that should exchange the battery, the number of charging stations, and the distance between two adjacent charging stations. Shi-Chun Yang, Wen-Zhuang Gou, Tie-Qiao Tang, and Hua-Yan Shang Copyright © 2014 Shi-Chun Yang et al. All rights reserved. Incentive Decision on Safety Investment of Supply Chain of Agricultural Products in “Agricultural Super-Docking” Wed, 29 Oct 2014 09:20:46 +0000 http://www.hindawi.com/journals/jam/2014/836342/ Since the “agriculture super-docking” mode was introduced in China in 2007, remarkable success has been made in reducing the transaction cost and improving the quality safety of agricultural products. However, the quality safety issues of agricultural products still occur frequently because both specialized farmers’ cooperatives and supermarkets have insufficient safety investment. In order to study the necessity, goal, and incentive decision schemes of safety investment in “agriculture super-docking” supply chain, three kinds of models, which include noncooperatives distributed decision-making model, centralized decision-making model, and incentive coordination models led by cooperatives and supermarkets, are, respectively, set up in this paper. Conclusions are drawn as follows: when making the uncooperative decentralized decision, both cooperatives and supermarkets have the moral risks to decrease the safety investment, but appropriate measures can achieve the coordination of the supply chain; when achieving the coordination of supply chain, the two contacts under the guidance of cooperatives and supermarkets are the same, and the schemes of distributing profits are also the same. Moreover, a practical case is given to improve the effectiveness and feasibility of the incentive decision schemes. Weiqin Tang, Weimin Tang, Changsheng Jiang, and Shan Lu Copyright © 2014 Weiqin Tang et al. All rights reserved.