Journal of Applied Mathematics The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Multipoint Iterative Methods for Finding All the Simple Zeros in an Interval Thu, 24 Jul 2014 14:04:25 +0000 Two new families of multipoint without memory iterative methods with eighth- and sixteenth-orders are constructed using the symbolic software Mathematica. The key idea in constructing such methods is based on producing some generic suitable functions to reduce the functional evaluations and increase the order of convergence along the computational efficiency. Again by applying Mathematica, we design a hybrid algorithm to capture all the simple real solutions of nonlinear equations in an interval. The application of the new schemes in producing fractal pictures is also furnished. T. Lotfi, F. Soleymani, S. Sharifi, S. Shateyi, and F. Khaksar Haghani Copyright © 2014 T. Lotfi et al. All rights reserved. Multifeature Fusion Vehicle Detection Algorithm Based on Choquet Integral Thu, 24 Jul 2014 12:33:42 +0000 Vision-based multivehicle detection plays an important role in Forward Collision Warning Systems (FCWS) and Blind Spot Detection Systems (BSDS). The performance of these systems depends on the real-time capability, accuracy, and robustness of vehicle detection methods. To improve the accuracy of vehicle detection algorithm, we propose a multifeature fusion vehicle detection algorithm based on Choquet integral. This algorithm divides the vehicle detection problem into two phases: feature similarity measure and multifeature fusion. In the feature similarity measure phase, we first propose a taillight-based vehicle detection method, and then vehicle taillight feature similarity measure is defined. Second, combining with the definition of Choquet integral, the vehicle symmetry similarity measure and the HOG + AdaBoost feature similarity measure are defined. Finally, these three features are fused together by Choquet integral. Being evaluated on public test collections and our own test images, the experimental results show that our method has achieved effective and robust multivehicle detection in complicated environments. Our method can not only improve the detection rate but also reduce the false alarm rate, which meets the engineering requirements of Advanced Driving Assistance Systems (ADAS). Wenhui Li, Peixun Liu, Ying Wang, and Hongyin Ni Copyright © 2014 Wenhui Li et al. All rights reserved. Performance-Based Evaluation of Large Steel-Framed Structures in the Overall Fire Process Thu, 24 Jul 2014 11:56:02 +0000 This paper proposes a systematic analysis of fire hazards within an oversized steel-framed building that is taller and wider than usual, using a performance-based approach. We put forth both the method and the performance criteria for performance-based fire design of oversized steel-framed buildings and quantitatively evaluate the hazard factors (smoke temperature, smoke visibility, smoke toxicity, and structural collapse) in fire condition. FDS large eddy simulation and a modified temperature rise model of oversized steel structures were proposed for the quantitative analysis of hazard factors. Furthermore, we also studied evacuation process from oversized buildings and found that the Pathfinder model (developed based on water conservation model and behavior model) can accurately predict the evacuation process from oversized buildings based on our experimental study of an evacuation from a stadium. By comparing the time of occurrence of fire hazard factors (smoke temperature, smoke visibility, smoke toxicity, and structural collapse) and the time needed for safe evacuation, we could conduct a quantitative fire risk assessment on personal evacuation. And the time of occurrence of fire hazard factors can also provide a theoretical reference for emergency rescuers. Guoqing Zhu, Guowei Zhang, Guanglin Yuan, and Qingtao Li Copyright © 2014 Guoqing Zhu et al. All rights reserved. Boundary Layer Flow due to the Vibration of a Sphere Thu, 24 Jul 2014 11:54:34 +0000 Boundary layer flow of the Newtonian fluid that is caused by the vibration of inner sphere while the outer sphere is at rest is calculated. Vishik-Lyusternik (Nayfeh refers to this method as the method of composite expansions) method is employed to construct an asymptotic expansion of the solution of the Navier-Stokes equations in the limit of high-frequency vibrations for Reynolds number of . The effect of the Stokes drift of fluid particles is also considered. Muhammad Adil Sadiq Copyright © 2014 Muhammad Adil Sadiq. All rights reserved. Dynamics of a Stochastic Multigroup SEIR Epidemic Model Thu, 24 Jul 2014 11:27:22 +0000 To be more precise about the real world activity, a stochastic multigroup SEIR epidemic model is formulated. we define the basic reproduction number and show that it is a sharp threshold for the dynamics of SDE model. If , the disease-free equilibrium is asymptotically stable; and if , the disease persists and there exists a globally asymptotically stable stationary distribution. Numerical simulation examples are carried out to substantiate the analytical results. Xiaojing Zhong and Feiqi Deng Copyright © 2014 Xiaojing Zhong and Feiqi Deng. All rights reserved. Efficient Big Integer Multiplication and Squaring Algorithms for Cryptographic Applications Thu, 24 Jul 2014 10:04:35 +0000 Public-key cryptosystems are broadly employed to provide security for digital information. Improving the efficiency of public-key cryptosystem through speeding up calculation and using fewer resources are among the main goals of cryptography research. In this paper, we introduce new symbols extracted from binary representation of integers called Big-ones. We present a modified version of the classical multiplication and squaring algorithms based on the Big-ones to improve the efficiency of big integer multiplication and squaring in number theory based cryptosystems. Compared to the adopted classical and Karatsuba multiplication algorithms for squaring, the proposed squaring algorithm is 2 to 3.7 and 7.9 to 2.5 times faster for squaring 32-bit and 8-Kbit numbers, respectively. The proposed multiplication algorithm is also 2.3 to 3.9 and 7 to 2.4 times faster for multiplying 32-bit and 8-Kbit numbers, respectively. The number theory based cryptosystems, which are operating in the range of 1-Kbit to 4-Kbit integers, are directly benefited from the proposed method since multiplication and squaring are the main operations in most of these systems. Shahram Jahani, Azman Samsudin, and Kumbakonam Govindarajan Subramanian Copyright © 2014 Shahram Jahani et al. All rights reserved. A Selection Model to Logistic Centers Based on TOPSIS and MCGP Methods: The Case of Airline Industry Thu, 24 Jul 2014 09:33:47 +0000 The location selection of a logistics center is a crucial decision relating to cost and benefit analysis in airline industry. However, it is difficult to be solved because there are many conflicting and multiple objectives in location problems. To solve the problem, this paper integrates fuzzy technique for order preference by similarity to an ideal solution (TOPSIS) and multichoice goal programming (MCGP) to obtain an appropriate logistics center from many alternative locations for airline industry. The proposed method in this paper will offer the decision makers (DMs) to set multiple aspiration levels for the decision criteria. A numerical example of application is also presented. Kou-Huang Chen, Chin-Nung Liao, and Li-Chun Wu Copyright © 2014 Kou-Huang Chen et al. All rights reserved. Simplified Adaptive Robust Motion Control with Varying Boundary Discontinuous Projection of Hydraulic Actuator Thu, 24 Jul 2014 08:44:38 +0000 This paper deals with the high performance adaptive robust motion control of electrohydraulic servo system driven by dual vane hydraulic rotary actuator. The recently developed adaptive robust control theory is used to handle the nonlinearities and modelling uncertainties in hydraulic systems. Aside from the difficulty of handling parametric variations, the traditional adaptive robust controller (ARC) is also a little complicated in practice. To address these challenging issues, a simplified adaptive robust control with varying boundary discontinuous projection is developed to enhance the robustness of the closed-loop system, based on the features of hydraulic rotary actuator. Compared with previous ARC controller, the resulting controller has a simple algorithm for more suitable implementation and can handle parametric variations via nonlinear robust design. The controller theoretically achieves a guaranteed transient performance and final tracking accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. Extensive simulation results are obtained for a hydraulic rotary actuator to verify the high performance nature of proposed control strategy. Cungui Yu and Xianwei Qi Copyright © 2014 Cungui Yu and Xianwei Qi. All rights reserved. Novel Techniques to Speed Up the Computation of the Automorphism Group of a Graph Thu, 24 Jul 2014 08:19:53 +0000 Graph automorphism (GA) is a classical problem, in which the objective is to compute the automorphism group of an input graph. Most GA algorithms explore a search tree using the individualization-refinement procedure. Four novel techniques are proposed which increase the performance of any algorithm of this type by reducing the depth of the search tree and by effectively pruning it. We formally prove that a GA algorithm that uses these techniques correctly computes the automorphism group of an input graph. Then, we describe how these techniques have been incorporated into the GA algorithm conauto, as conauto-2.03, with at most an additive polynomial increase in its asymptotic time complexity. Using a benchmark of different graph families, we have evaluated the impact of these techniques on the size of the search tree, observing a significant reduction both when they are applied individually and when all of them are applied together. This is also reflected in a reduction of the running time, which is substantial for some graph families. Finally, we have compared the search tree size of conauto-2.03 against those of other popular GA algorithms, observing that, in most cases, conauto explores less nodes than these algorithms. José Luis López-Presa, Luis F. Chiroque, and Antonio Fernández Anta Copyright © 2014 José Luis López-Presa et al. All rights reserved. A Numerical Convolution Representation of Potential for a Disk Surface Density in 3D Thu, 24 Jul 2014 07:15:40 +0000 This study presents a numerical convolution representation of a potential induced from a disk of surface density, which has often been investigated in the center region of galaxies. The advantage of this representation is to release the softening length for the -body method and artificial boundary conditions for the spectral methods. With the help of fast Fourier transform, the computational complexity is only , where is the number of zones in one dimension. Numerical results show an almost second order of accuracy on a Cartesian coordinate system. A comparison study also demonstrates that this method can calculate the potential for disk surface density based on the uniform grids. Chien-Chang Yen Copyright © 2014 Chien-Chang Yen. All rights reserved. Formalization of Function Matrix Theory in HOL Thu, 24 Jul 2014 07:01:35 +0000 Function matrices, in which elements are functions rather than numbers, are widely used in model analysis of dynamic systems such as control systems and robotics. In safety-critical applications, the dynamic systems are required to be analyzed formally and accurately to ensure their correctness and safeness. Higher-order logic (HOL) theorem proving is a promise technique to match the requirement. This paper proposes a higher-order logic formalization of the function vector and the function matrix theories using the HOL theorem prover, including data types, operations, and their properties, and further presents formalization of the differential and integral of function vectors and function matrices. The formalization is implemented as a library in the HOL system. A case study, a formal analysis of differential of quadratic functions, is presented to show the usefulness of the proposed formalization. Zhiping Shi, Zhenke Liu, Yong Guan, Shiwei Ye, Jie Zhang, and Hongxing Wei Copyright © 2014 Zhiping Shi et al. All rights reserved. Improved Crosstalk Reduction on Multiview 3D Display by Using BILS Algorithm Thu, 24 Jul 2014 06:41:49 +0000 In multiview three-dimensional (3D) displays, crosstalk is one of the most annoying artefacts degrading the quality of the 3D image. In this paper, we present a system-introduced crosstalk measurement method and derive an improved crosstalk reduction method. The proposed measurement method is applied to measure the exact crosstalk among subpixels corresponding to different view images and the obtained results are very effective for crosstalk reduction method. Furthermore, an improved crosstalk reduction method is proposed to alleviate crosstalk by searching for the optimal integral intensity values of subpixels on the synthetic image. The derived algorithm based on modified Schnorr-Euchner strategy is implemented to seek the optimal solution to this box-constrained integer least squares (BILS) problem, such that the Euclidean distance between solution and its target decreases substantially. The method we develop is applicable to both multiview 3D parallax barrier displays and multiview 3D lenticular displays. Both simulation and experimental results indicate that the derived method is capable of improving 3D image quality more effectively than the existing method on multiview 3D displays. Xiaoyan Wang and Chunping Hou Copyright © 2014 Xiaoyan Wang and Chunping Hou. All rights reserved. Model and Topological Characteristics of Power Distribution System Security Region Thu, 24 Jul 2014 00:00:00 +0000 As an important tool of transmission system dispatching, the region-based method has just been introduced into distribution area with the ongoing smart distribution grid initiatives. First, a more accurate distribution system security region (DSSR) model is proposed. The proposed model is based on detailed feeder-interconnected topology, and both substation transformer and feeder N-1 contingencies are considered. Second, generic characteristics of DSSR are discussed and mathematically proved. That is, DSSR is a dense set of which boundary has no suspension and can be expressed by several union subsurfaces. Finally, the results from both a test case and a practical case demonstrate the effectiveness of the proposed modeling approach; the shape of DSSR is also illustrated by means of 2- and 3-dimensional visualization. Moreover, the DSSR-based assessment and control are preliminary illustrated to show the application of DSSR. The researches in this paper are fundamental work to develop new security region theory for future distribution systems. Jun Xiao, Guo-qiang Zu, Xiao-xu Gong, and Cheng-shan Wang Copyright © 2014 Jun Xiao et al. All rights reserved. A New Model of Ultracapacitors Based on Fractal Fundamentals Wed, 23 Jul 2014 13:38:27 +0000 An intuitive model is proposed in this paper to describe the electrical behavior of certain ultracapacitors. The model is based on a simple expression that can be fully characterized by five real numbers. In this paper, the measured impedances of three ultracapacitors as a function of frequency are compared to model results. There is good agreement between the model and measurements. Results presented in a previous study are also reviewed and the paper demonstrates that those results are also consistent with the newly described model. Xiaodong Zhang, Yi Sun, Jia Song, Aijun Wu, and Xiaoyan Cui Copyright © 2014 Xiaodong Zhang et al. All rights reserved. Evaluation of Underground Zinc Mine Investment Based on Fuzzy-Interval Grey System Theory and Geometric Brownian Motion Wed, 23 Jul 2014 11:07:39 +0000 Underground mine projects are often associated with diverse sources of uncertainties. Having the ability to plan for these uncertainties plays a key role in the process of project evaluation and is increasingly recognized as critical to mining project success. To make the best decision, based on the information available, it is necessary to develop an adequate model incorporating the uncertainty of the input parameters. The model is developed on the basis of full discounted cash flow analysis of an underground zinc mine project. The relationships between input variables and economic outcomes are complex and often nonlinear. Fuzzy-interval grey system theory is used to forecast zinc metal prices while geometric Brownian motion is used to forecast operating costs over the time frame of the project. To quantify the uncertainty in the parameters within a project, such as capital investment, ore grade, mill recovery, metal content of concentrate, and discount rate, we have applied the concept of interval numbers. The final decision related to project acceptance is based on the net present value of the cash flows generated by the simulation over the time project horizon. Zoran Gligoric, Lazar Kricak, Cedomir Beljic, Suzana Lutovac, and Jelena Milojevic Copyright © 2014 Zoran Gligoric et al. All rights reserved. A Fast Independent Component Analysis Algorithm for Geochemical Anomaly Detection and Its Application to Soil Geochemistry Data Processing Wed, 23 Jul 2014 10:59:35 +0000 A fast independent component analysis algorithm (FICAA) is introduced to process geochemical data for anomaly detection. In geochemical data processing, the geological significance of separated geochemical elements must be explicit. This requires that correlation coefficients be used to overcome the limitation of indeterminacy for the sequences of decomposed signals by the FICAA, so that the sequences of the decomposed signals can be correctly reflected. Meanwhile, the problem of indeterminacy in the scaling of the decomposed signals by the FICAA can be solved by the cumulative frequency method (CFM). To classify surface geochemical samples into true anomalies and false anomalies, assays of the 1 : 10 000 soil geochemical data in the area of Dachaidan in the Qinghai province of China are processed. The CFM and FICAA are used to detect the anomalies of Cu and Au. The results of this research demonstrate that the FICAA can demultiplex the mixed signals and achieve results similar to actual mineralization when 85%, 95%, and 98% are chosen as three levels of anomaly delineation. However, the traditional CFM failed to produce realistic results and has no significant use for prospecting indication. It is shown that application of the FICAA to geochemical data processing is effective. Bin Liu, Si Guo, Youhua Wei, and Zedong Zhan Copyright © 2014 Bin Liu et al. All rights reserved. A Rational Threshold Signature Model and Protocol Based on Different Permissions Wed, 23 Jul 2014 09:20:05 +0000 This paper develops a novel model and protocol used in some specific scenarios, in which the participants of multiple groups with different permissions can finish the signature together. We apply the secret sharing scheme based on difference equation to the private key distribution phase and secret reconstruction phrase of our threshold signature scheme. In addition, our scheme can achieve the signature success because of the punishment strategy of the repeated rational secret sharing. Besides, the bit commitment and verification method used to detect players’ cheating behavior acts as a contributing factor to prevent the internal fraud. Using bit commitments, verifiable parameters, and time sequences, this paper constructs a dynamic game model, which has the features of threshold signature management with different permissions, cheat proof, and forward security. Bojun Wang, Cheng Cai, and Quan Zhou Copyright © 2014 Bojun Wang et al. All rights reserved. Accurate Evaluation of Polynomials in Legendre Basis Wed, 23 Jul 2014 08:15:10 +0000 This paper presents a compensated algorithm for accurate evaluation of a polynomial in Legendre basis. Since the coefficients of the evaluated polynomial are fractions, we propose to store these coefficients in two floating point numbers, such as double-double format, to reduce the effect of the coefficients’ perturbation. The proposed algorithm is obtained by applying error-free transformation to improve the Clenshaw algorithm. It can yield a full working precision accuracy for the ill-conditioned polynomial evaluation. Forward error analysis and numerical experiments illustrate the accuracy and efficiency of the algorithm. Peibing Du, Hao Jiang, and Lizhi Cheng Copyright © 2014 Peibing Du et al. All rights reserved. Research on the Performance of Electric Vehicles in Peak Load Shifting Wed, 23 Jul 2014 07:13:10 +0000 Electric vehicles (EVs) are developing remarkably fast these years which makes the technology of vehicle-to-grid (V2G) easier to implement. Peak load shifting (PLS) is an important part of V2G service. A model of EVs’ capacity in V2G service is proposed for the research on PLS in this paper. The capacity is valued in accordance with three types of situations. Based on the model, three different scenarios are suggested in order to evaluate the capacity with MATLAB. The evaluation results indicate that EVs can provide potential energy to participate in PLS. Then, the principle of PLS with EVs is researched through the analysis of the relationship between their power and capacity. The performance of EVs in PLS is also simulated. The comparison of two simulation results shows that EVs can fulfill the request of PLS without intensely lowering their capacity level. Qingshan Xu, Yujun Liu, Maosheng Ding, Pingliang Zeng, and Wei Pan Copyright © 2014 Qingshan Xu et al. All rights reserved. Misplaced Inventory and Lead-Time in the Supply Chain: Analysis of Decision-Making on RFID Investment with Service Level Wed, 23 Jul 2014 00:00:00 +0000 Radio-frequency identification (RFID), as the key technology of Internet of Things (IoT), has been hailed as a major innovation to solve misplaced inventory and reduce lead-time. Many retailers have been pushing their suppliers to invest this technology. However, its associated costs seem to prohibit its widespread application. This paper analyzes the situation of service level in a retail supply chain, which has resulted from misplaced inventory and lead-time. By newsvendor model, we analyze the difference between with- and without-RFID technologies in service level of centralized and decentralized supply chains, respectively. Then with different service levels, we determine the tag cost thresholds at which RFID technology investment becomes profitable in centralized and decentralized supply chains, respectively. Furthermore, we apply a linear transfer payment coefficient strategy to coordinate with the decentralized supply chain. It is found that whether the adoption of RFID technology improves the service level depends on the cost of RFID tag in the centralized system, but it improves the service level in the decentralized system when only the supplier bears the cost of RFID tag. Moreover, the same cost thresholds of RFID tag with different service levels exist in both the centralized and the decentralized cases. Li-Hao Zhang, Ti-Jun Fan, Wen-Chyuan Chiang, and Feng Tao Copyright © 2014 Li-Hao Zhang et al. All rights reserved. The Cauchy Problem for a Dissipative Periodic 2-Component Degasperis-Procesi System Wed, 23 Jul 2014 00:00:00 +0000 The dissipative periodic 2-component Degasperis-Procesi system is investigated. A local well-posedness for the system in Besov space is established by using the Littlewood-Paley theory and a priori estimates for the solutions of transport equation. The wave-breaking criterions for strong solutions to the system with certain initial data are derived. Sen Ming, Han Yang, and Ls Yong Copyright © 2014 Sen Ming et al. All rights reserved. A Multiple Iterated Integral Inequality and Applications Tue, 22 Jul 2014 14:09:46 +0000 We establish new multiple iterated Volterra-Fredholm type integral inequalities, where the composite function of the unknown function with nonlinear function in integral functions in [Ma, QH, Pečarić, J: Estimates on solutions of some new nonlinear retarded Volterra-Fredholm type integral inequalities. Nonlinear Anal. 69 (2008) 393–407] is changed into the composite functions of the unknown function with different nonlinear functions , respectively. By adopting novel analysis techniques, the upper bounds of the embedded unknown functions are estimated explicitly. The derived results can be applied in the study of solutions of ordinary differential equations and integral equations. Zongyi Hou and Wu-Sheng Wang Copyright © 2014 Zongyi Hou and Wu-Sheng Wang. All rights reserved. Optimal Polynomial Decay to Coupled Wave Equations and Its Numerical Properties Tue, 22 Jul 2014 11:39:55 +0000 In this work we consider a coupled system of two weakly dissipative wave equations. We show that the solution of this system decays polynomially and the decay rate is optimal. Computational experiments are conducted in the one-dimensional case in order to show that the energies properties are preserved. In particular, we use finite differences and also spectral methods. R. F. C. Lobato, S. M. S. Cordeiro, M. L. Santos, and D. S. Almeida Júnior Copyright © 2014 R. F. C. Lobato et al. All rights reserved. A Computationally Efficient Iterative Algorithm for Estimating the Parameter of Chirp Signal Model Tue, 22 Jul 2014 11:27:32 +0000 The parameter estimation of Chirp signal model in additive noises when all the noises are independently and identically distributed (i.i.d.) has been considered. A novel iterative algorithm is proposed to estimate the frequency rate of the considered model by constructing the iterative statistics with one-lag and multilag differential signals. It is observed that the estimator for the iterative algorithm is consistent and works quite well in terms of biases and mean squared errors. Moreover, the convergence rate of the estimator is improved from of the initial estimator to for one-lag differential signal condition and from of the initial estimator to for multilag differential signal condition, respectively, by only three iterations. The range of the lag is discussed and the optimal lag is obtained for the multilag differential signal condition when the lag is of order . The estimator of frequency rate with optimal lag is very close to Cramer-Rao lower bound (CRLB) as well as the asymptotic variance of least-squares estimator (LSE) at moderate signal-to-noise ratio (SNR). Finally, simulation experiments are performed to verify the effectiveness of the algorithm. Jiawen Bian, Jing Xing, Zhihui Liu, Lihua Fu, and Hongwei Li Copyright © 2014 Jiawen Bian et al. All rights reserved. A Note on the Normal Index and the c-Section of Maximal Subgroups of a Finite Group Tue, 22 Jul 2014 10:09:31 +0000 Let be a maximal subgroup of finite group . For each chief factor of such that and , we called the order of the normal index of and a section of in . Using the concepts of normal index and c-section, we obtain some new characterizations of p-solvable, 2-supersolvable, and p-nilpotent. Na Tang and Xianhua Li Copyright © 2014 Na Tang and Xianhua Li. All rights reserved. Estimation of Unknown Functions of Iterative Difference Inequalities and Their Applications Tue, 22 Jul 2014 10:04:52 +0000 We establish some new nonlinear retarded finite difference inequalities. The results that we propose here can be used as tools in the theory of certain new classes of finite difference equations in various difference situations. We also give applications of the inequalities to show the usefulness of our results. Ricai Luo, Wu-Sheng Wang, and Honglei Xu Copyright © 2014 Ricai Luo et al. All rights reserved. Quad-Rotor Helicopter Autonomous Navigation Based on Vanishing Point Algorithm Tue, 22 Jul 2014 08:29:20 +0000 Quad-rotor helicopter is becoming popular increasingly as they can well implement many flight missions in more challenging environments, with lower risk of damaging itself and its surroundings. They are employed in many applications, from military operations to civilian tasks. Quad-rotor helicopter autonomous navigation based on the vanishing point fast estimation (VPFE) algorithm using clustering principle is implemented in this paper. For images collected by the camera of quad-rotor helicopter, the system executes the process of preprocessing of image, deleting noise interference, edge extracting using Canny operator, and extracting straight lines by randomized hough transformation (RHT) method. Then system obtains the position of vanishing point and regards it as destination point and finally controls the autonomous navigation of the quad-rotor helicopter by continuous modification according to the calculated navigation error. The experimental results show that the quad-rotor helicopter can implement the destination navigation well in the indoor environment. Jialiang Wang, Hai Zhao, Yuanguo Bi, Xingchi Chen, Ruofan Zeng, and Shiliang Shao Copyright © 2014 Jialiang Wang et al. All rights reserved. Comparison of a Fuzzy Genetic and Simulated Annealing Algorithm Approach for Project Time-Cost Tradeoff Tue, 22 Jul 2014 07:33:01 +0000 Project planning, defining the limitations and resources by leveling the resources available, have a great importance for the management projects. All these activities directly affect the duration and the cost of the project. To get a competitive value on the market, the project must be completed at the optimum time. In other to be competitive enough the optimum or near optimum solutions of time cost tradeoff and the resource leveling and resource constrained scheduling problems should be obtained in the planning phase of the project. One important aspect of the project management is activity crashing, that is, reducing activity time by adding more resources such as workers and overtime. It is important to decide the optimal crash plan to complete the project within the desired time period. The comparison of fuzzy simulated annealing and the genetic algorithm based on the crashing method is introduced in this paper to evaluate project networks and determine the optimum crashing configuration that minimizes the average project cost, caused by being late and crashing costs in the presence of vagueness and uncertainty. The evaluation results based on a real case study indicate that the method can be reliably applied to engineering projects. Nataša Glišović Copyright © 2014 Nataša Glišović. All rights reserved. Hopf Bifurcation Analysis in a New Chaotic System with Chaos Entanglement Function Tue, 22 Jul 2014 07:05:32 +0000 A new approach to generate chaotic phenomenon, called chaos entanglement, is introduced in this paper. The basic principle is to entangle two or multiple stable linear subsystems by entanglement functions to form an artificial chaotic system such that each of them evolves in a chaotic manner. The Hopf bifurcation of a new chaotic system with chaos entanglement function is studied. More precisely, we study the stability and bifurcations of equilibrium in the new chaotic system. Besides, we controlled the system to any fixed point to eliminate the chaotic vibration by means of sliding mode method. And the numerical simulations were presented to confirm the effectiveness of the controller. Zhang Jiangang, Chu Yandong, Du Wenju, Chang Yingxiang, and An Xinlei Copyright © 2014 Zhang Jiangang et al. All rights reserved. Stepped Fault Line Selection Method Based on Spectral Kurtosis and Relative Energy Entropy of Small Current to Ground System Tue, 22 Jul 2014 00:00:00 +0000 This paper proposes a stepped selection method based on spectral kurtosis relative energy entropy. Firstly, the length and type of window function are set; then when fault occurs, enter step 1: the polarity of first half-wave extremes is analyzed; if the ratios of extremes between neighboring lines are positive, the bus bar is the fault line, else, the SK relative energy entropies are calculated, and then enter step 2: if the obtained entropy multiple is bigger than the threshold or equal to the threshold, the overhead line of max entropy corresponding is the fault line, if not, enter step 3: the line of max entropy corresponding is the fault line. At last, the applicability of the proposed algorithm is presented, and the comparison results are discussed. Xiaowei Wang, Xiangxiang Wei, Jie Gao, Yaxiao Hou, and Yanfang Wei Copyright © 2014 Xiaowei Wang et al. All rights reserved.