Mathematical Problems in Engineering The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. A New Approach of Asymmetric Homoclinic and Heteroclinic Orbits Construction in Several Typical Systems Based on the Undetermined Padé Approximation Method Thu, 28 Jul 2016 16:26:22 +0000 In dynamic systems, some nonlinearities generate special connection problems of non-Z2 symmetric homoclinic and heteroclinic orbits. Such orbits are important for analyzing problems of global bifurcation and chaos. In this paper, a general analytical method, based on the undetermined Padé approximation method, is proposed to construct non-Z2 symmetric homoclinic and heteroclinic orbits which are affected by nonlinearity factors. Geometric and symmetrical characteristics of non-Z2 heteroclinic orbits are analyzed in detail. An undetermined frequency coefficient and a corresponding new analytic expression are introduced to improve the accuracy of the orbit trajectory. The proposed method shows high precision results for the Nagumo system (one single orbit); general types of non-Z2 symmetric nonlinear quintic systems (orbit with one cusp); and Z2 symmetric system with high-order nonlinear terms (orbit with two cusps). Finally, numerical simulations are used to verify the techniques and demonstrate the enhanced efficiency and precision of the proposed method. Jingjing Feng, Qichang Zhang, Wei Wang, and Shuying Hao Copyright © 2016 Jingjing Feng et al. All rights reserved. Nonfragile Robust Model Predictive Control for Uncertain Constrained Systems with Time-Delay Compensation Thu, 28 Jul 2016 10:03:58 +0000 This study investigates the problem of asymptotic stabilization for a class of discrete-time linear uncertain time-delayed systems with input constraints. Parametric uncertainty is assumed to be structured, and delay is assumed to be known. In Lyapunov stability theory framework, two synthesis schemes of designing nonfragile robust model predictive control (RMPC) with time-delay compensation are put forward, where the additive and the multiplicative gain perturbations are, respectively, considered. First, by designing appropriate Lyapunov-Krasovskii (L-K) functions, the robust performance index is defined as optimization problems that minimize upper bounds of infinite horizon cost function. Then, to guarantee closed-loop stability, the sufficient conditions for the existence of desired nonfragile RMPC are obtained in terms of linear matrix inequalities (LMIs). Finally, two numerical examples are provided to illustrate the effectiveness of the proposed approaches. Wei Jiang, Hong-li Wang, Jing-hui Lu, Wei-wei Qin, and Guang-bin Cai Copyright © 2016 Wei Jiang et al. All rights reserved. A Novel Margin-Based Measure for Directed Hill Climbing Ensemble Pruning Thu, 28 Jul 2016 09:50:24 +0000 Ensemble pruning is a technique to increase ensemble accuracy and reduce its size by choosing a subset of ensemble members to form a subensemble for prediction. Many ensemble pruning algorithms via directed hill climbing searching policy have been recently proposed. The key to the success of these algorithms is to construct an effective measure to supervise the search process. In this paper, we study the importance of individual classifiers with respect to an ensemble using margin theory proposed by Schapire et al. and obtain that ensemble pruning via directed hill climbing strategy should focus more on examples with small absolute margins as well as classifiers that correctly classify more examples. Based on this principle, we propose a novel measure called the margin-based measure to explicitly evaluate the importance of individual classifiers. Our experiments show that using the proposed measure to prune an ensemble leads to significantly better accuracy results compared to other state-of-the-art measures. Huaping Guo, Fang Sun, Jiong Cheng, Yanling Li, and Mingling Xu Copyright © 2016 Huaping Guo et al. All rights reserved. Guard Band-Based Resource Sharing for Device-to-Device Communications Underlying Cellular Network Thu, 28 Jul 2016 08:00:01 +0000 The performance of device-to-device (D2D) communication in a cellular network depends on the resource sharing between D2D links and cellular users. Existing researches on resource sharing mainly focus on power control between the D2D users and cellular users that operate in the same frequency band. However, the D2D outage probability performance is hampered by the cellular interference to D2D links. Therefore, the D2D users may not achieve satisfactory SINR performance when D2D users and cellular users are geographically located in a small area; as a result, the outage probability performance would be significantly degraded. In this paper, we provide a novel resource sharing strategy to mitigate the interference from cellular users to D2D receivers by utilizing the low energy characteristics of signals in the guard band and analyze the D2D outage probability performance mathematically. Both the mathematical analysis and numerical results show that the proposed resource sharing strategy provides 1.2 dB SNR gain in D2D outage probability performance while guaranteeing the cellular throughputs. Yue Li, Xuejun Sha, Liang Ye, and Xiaojie Fang Copyright © 2016 Yue Li et al. All rights reserved. Stability Analysis of Anchored Soil Slope Based on Finite Element Limit Equilibrium Method Thu, 28 Jul 2016 06:14:33 +0000 Under the condition of the plane strain, finite element limit equilibrium method is used to study some key problems of stability analysis for anchored slope. The definition of safe factor in slices method is generalized into FEM. The “true” stress field in the whole structure can be obtained by elastic-plastic finite element analysis. Then, the optimal search for the most dangerous sliding surface with Hooke-Jeeves optimized searching method is introduced. Three cases of stability analysis of natural slope, anchored slope with seepage, and excavation anchored slope are conducted. The differences in safety factor quantity, shape and location of slip surface, anchoring effect among slices method, finite element strength reduction method (SRM), and finite element limit equilibrium method are comparatively analyzed. The results show that the safety factor given by the FEM is greater and the unfavorable slip surface is deeper than that by the slice method. The finite element limit equilibrium method has high calculation accuracy, and to some extent the slice method underestimates the effect of anchor, and the effect of anchor is overrated in the SRM. Rui Zhang, Jie Zhao, and Guixuan Wang Copyright © 2016 Rui Zhang et al. All rights reserved. An Efficient Method for Convex Constrained Rank Minimization Problems Based on DC Programming Wed, 27 Jul 2016 14:19:17 +0000 The constrained rank minimization problem has various applications in many fields including machine learning, control, and signal processing. In this paper, we consider the convex constrained rank minimization problem. By introducing a new variable and penalizing an equality constraint to objective function, we reformulate the convex objective function with a rank constraint as a difference of convex functions based on the closed-form solutions, which can be reformulated as DC programming. A stepwise linear approximative algorithm is provided for solving the reformulated model. The performance of our method is tested by applying it to affine rank minimization problems and max-cut problems. Numerical results demonstrate that the method is effective and of high recoverability and results on max-cut show that the method is feasible, which provides better lower bounds and lower rank solutions compared with improved approximation algorithm using semidefinite programming, and they are close to the results of the latest researches. Wanping Yang, Jinkai Zhao, and Fengmin Xu Copyright © 2016 Wanping Yang et al. All rights reserved. Coadjoint Formalism: Nonorthogonal Basis Problems Wed, 27 Jul 2016 14:06:01 +0000 Using nonorthogonal bases in spectral methods demands considerable effort, because applying the Gram-Schmidt process is a fundamental condition for calculations. However, operational matrices numerical methods are being used in an increasing way and extensions for nonorthogonal bases appear, requiring simplified procedures. Here, extending previous work, an efficient tensorial method is presented, in order to simplify the calculations related to the use of nonorthogonal bases in spectral numerical problems. The method is called coadjoint formalism and is based on bracket Dirac’s formulation of quantum mechanics. Some examples are presented, showing how simple it is to use the method. William Labecca, Osvaldo Guimarães, and José Roberto C. Piqueira Copyright © 2016 William Labecca et al. All rights reserved. The Optimization Model for Electric System Emergency Facility Storage and Transportation Considering Information Credibility Wed, 27 Jul 2016 11:43:22 +0000 When dealing with power system emergency caused by natural disaster, information survey is the important foundation of emergency power supply and repair. The information credibility would directly inflect the credibility and timeliness of electric system emergency work. Therefore, this paper starts the study from the point of information credibility and sets minimizing total cost and loss as the objective function, taking time constraint, transportation road constraint, information credibility constraint, and the parameters of different facilities into consideration and building a location and storage optimization model for electric system emergency facility. And a corresponding facility transportation model was built considering the power loss in demand points. The simulation result shows that the models proposed by this paper could satisfy the requirement of information credibility, improve the adaptability to demand change, and cut down total cost and loss. Guan Wang, Huan-Huan Li, Li-Wei Ju, Zhong-Fu Tan, Chuang Deng, and Jun-Yong Liu Copyright © 2016 Guan Wang et al. All rights reserved. Parameters in Multiphase Flowing of Natural Gas NGH Slurry via Vertical Pipe Wed, 27 Jul 2016 11:23:59 +0000 In recent years, the pipeline flowing of natural gas hydrate (hereinafter NGH) slurry has been a promising technique of multiphase flowing via pipe and that of crushed hydrate mixture slurry is also a key technique in solid fluidization mining method of nondiagenetic NGH reservoir below the seabed. In this paper, by using similarity rules, a small-scale simulation model was established to shorten the calculation time. The correctness of the simulation model has been verified through comparison with experiment. Thereby, the distribution of velocity and volume fraction of each phase in the vertical pipe was obtained, and the prototype of vertical pipe was analyzed. By study on the pipe resistance, the pressure drop of slurry, when flowing in vertical pipe, could be calculated as . In the end, by adjusting volume fraction of particles in the mixture slurry, the relationship between the solid particles’ volume fraction and piezometric pressure drop was obtained. When the optimal flow velocity of the slurry is 2 m/s and the ratio of NGH volume fraction to that of sand is 4 : 1, the optimal particle volume fraction ranges from 20% to 40%. Dai Maolin and Wu Kaisong Copyright © 2016 Dai Maolin and Wu Kaisong. All rights reserved. Corrigendum to “On Two-Level State-Dependent Routing Polling Systems with Mixed Service” Wed, 27 Jul 2016 07:08:35 +0000 Guan Zheng, Yang Zhijun, Qian Wenhua, and He Min Copyright © 2016 Guan Zheng et al. All rights reserved. Design of Adaptive Switching Controller for Robotic Manipulators with Disturbance Tue, 26 Jul 2016 12:52:01 +0000 Two adaptive switching control strategies are proposed for the trajectory tracking problem of robotic manipulator in this paper. The first scheme is designed for the supremum of the bounded disturbance for robot manipulator being known; while the supremum is not known, the second scheme is proposed. Each proposed scheme consists of an adaptive switching law and a PD controller. Based on the Lyapunov stability theorem, it is shown that two new schemes can guarantee tracking performance of the robotic manipulator and be adapted to the alternating unknown loads. Simulations for two-link robotic manipulator are carried out and show that the two schemes can avoid the overlarge input torque, and the feasibility and validity of the proposed control schemes are proved. Zhen Yang, Shumin Fei, Fang Wang, Jiaguo Lv, and Xishang Dong Copyright © 2016 Zhen Yang et al. All rights reserved. Estimation of the Shear Stress Parameter of a Power-Law Fluid Mon, 25 Jul 2016 16:06:57 +0000 We apply the Adomian decomposition method to a power-law problem for solutions that do not change the sign of curvature. In particular we consider solutions with positive curvature. The power series obtained via the Adomian decomposition method is used to estimate the shear stress parameter as well as the instant of time where the solution reaches its terminal point of a steady state. We compare our results with estimates obtained via numerical integrators. More importantly we illustrate that the error is predictable and can be reduced without further effort or using higher order terms in the approximating series. Samer S. Al-Ashhab and Rubayyi T. Alqahtani Copyright © 2016 Samer S. Al-Ashhab and Rubayyi T. Alqahtani. All rights reserved. The Effects of Matched Filter on Stable Performance of Semistrapdown Inertially Stabilized Platform Mon, 25 Jul 2016 11:55:41 +0000 To enhance the optimization performance of matched filter and further improve line of sight (LOS) stability of platform in inertial space, the proposed matched filter algorithm is conducted by adjusting matched filter coefficients of first-order low pass filter utilizing the regional search method based on invariance principle. The coefficients of the fraction molecule and denominator of proposed regional search algorithm are altered instead of denominator coefficients only being modified. Simulations are performed to verify the validity of inside factors performed with stabilization control model and quartz rate sensor (QRS) mathematical model. The stable angular error is sharply alleviated, so the decoupling accuracy of airborne semistrapdown inertially stabilized platform is largely promoted. The optimization matched filter can effectively increase stability of LOS in inertial space. Feng Liu and Hua Wang Copyright © 2016 Feng Liu and Hua Wang. All rights reserved. Maximization of Visible Light Communication Capacity Employing Quasi-Linear Preequalization with Peak Power Limitation Mon, 25 Jul 2016 09:08:38 +0000 We propose quasi-linear preequalization to be used for high speed visible light communication (VLC) system. Compared with zero-forcing preequalization, this kind of preequalization method is more suitable for a real VLC experimental system with peak power limitation. We carry out simulations and experiments to test the performance of quasi-linear preequalization. With this equalizer, the 3 dB bandwidth of the system can be extended from 17 MHz to 450 MHz. We implement 2.32 Gbit/s phosphorescent white light-emitting diode (LED) VLC transmission over 1 m distance with quasi-linear equalizer, bit and power loading OFDM, differential amplification positive intrinsic negative diode (PIN) receivers, and maximum ratio combining algorithm. To our knowledge, this is the highest transmission data rate based on a phosphorescent white LED VLC system. Yingjun Zhou, Jianyang Shi, Zhixin Wang, Junwen Zhang, Xingxing Huang, and Nan Chi Copyright © 2016 Yingjun Zhou et al. All rights reserved. An Adaptive Dynamic Surface Controller for Ultralow Altitude Airdrop Flight Path Angle with Actuator Input Nonlinearity Mon, 25 Jul 2016 08:42:55 +0000 In the process of ultralow altitude airdrop, many factors such as actuator input dead-zone, backlash, uncertain external atmospheric disturbance, and model unknown nonlinearity affect the precision of trajectory tracking. In response, a robust adaptive neural network dynamic surface controller is developed. As a result, the aircraft longitudinal dynamics with actuator input nonlinearity is derived; the unknown nonlinear model functions are approximated by means of the RBF neural network. Also, an adaption strategy is used to achieve robustness against model uncertainties. Finally, it has been proved that all the signals in the closed-loop system are bounded and the tracking error converges to a small residual set asymptotically. Simulation results demonstrate the perfect tracking performance and strong robustness of the proposed method, which is not only applicable to the actuator with input dead-zone but also suitable for the backlash nonlinearity. At the same time, it can effectively overcome the effects of dead-zone and the atmospheric disturbance on the system and ensure the fast track of the desired flight path angle instruction, which overthrows the assumption that system functions must be known. Mao-long Lv, Xiu-xia Sun, Shu-guang Liu, and Dong Wang Copyright © 2016 Mao-long Lv et al. All rights reserved. A Study of Coordinated Vehicle Traction Control System Based on Optimal Slip Ratio Algorithm Mon, 25 Jul 2016 07:09:27 +0000 Under complicated situations, such as the low slippery road surface and split- road surface, traction control system is the key issue to improve the performance of vehicle acceleration and stability. In this paper, a novel control strategy with engine controller and active pressure controller is presented. First and foremost, an ideal vehicle model is proposed for simulation; then a method for the calculation of optimal slip ratio is also brought. Finally, the scheme of control method with engine controller and active brake controller is presented. From the results of simulation and road tests, it can be concluded that the acceleration performance and stability of a vehicle equipped with traction control system (TCS) can be improved. Gang Liu and LiQiang Jin Copyright © 2016 Gang Liu and LiQiang Jin. All rights reserved. Sparsity-Homotopy Perturbation Inversion Method with Wavelets and Applications to Black-Scholes Model and Todaro Model Thu, 21 Jul 2016 13:25:46 +0000 Sparsity regularization method plays an important role in reconstructing parameters. Compared with traditional regularization methods, sparsity regularization method has the ability to obtain better performance for reconstructing sparse parameters. However, sparsity regularization method does not have the ability to reconstruct smooth parameters. For overcoming this difficulty, we combine a sparsity regularization method with a wavelet method in order to transform smooth parameters into sparse parameters. We use a sparsity-homotopy perturbation inversion method to improve the accuracy and stability and apply the proposed method to reconstruct parameters for a Black-Scholes option pricing model and a Todaro model. Numerical experiments show that the proposed method is convergent and stable. Yixin Dou and Zhihao Wang Copyright © 2016 Yixin Dou and Zhihao Wang. All rights reserved. Development of Liquid Capacity Measuring Algorithm Based on Data Integration from Multiple Sensors Thu, 21 Jul 2016 13:05:26 +0000 This research proposes an algorithm using a process of integrating data from multiple sensors to measure the liquid capacity in real time regardless of the position of the liquid tank. The algorithm for measuring the capacity was created with a complementary filter using a Kalman filter in order to revise the level sensor data and IMU sensor data. The measuring precision of the proposed algorithm was assessed through repetitive experiments by varying the liquid capacity and the rotation angle of the liquid tank. The measurements of the capacity within the liquid tank were precise, even when the liquid tank was rotated. Using the proposed algorithm, one can obtain highly precise measurements, and it is affordable since an existing level sensor is used. Kiwoong Park, Si-Kyoung Lee, and Hyeon Cheol Kim Copyright © 2016 Kiwoong Park et al. All rights reserved. Robust Observer Based Disturbance Rejection Control for Euler-Lagrange Systems Thu, 21 Jul 2016 11:39:36 +0000 Robust disturbance rejection control methodology is proposed for Euler-Lagrange systems, and parameters optimization strategy for the observer is explored. First, the observer based disturbance rejection methodology is analyzed, based on which the disturbance rejection paradigm is proposed. Thus, a disturbance observer (DOB) with partial feedback linearization and a low-pass filter is proposed for nonlinear dynamic model under relaxed restrictions of the generalized disturbance. Then, the outer-loop backstepping controller is designed for desired tracking performance. Considering that the parameters of DOB cannot be obtained directly based on Lyapunov stability analysis, parameter of DOB is optimized under standard control framework. By analyzing the influence of outer-loop controller on the inner-loop observer parameter, robust stability constraint is proposed to guarantee the robust stability of the closed-loop system. Experiment on attitude tracking of an aircraft is carried out to show the effectiveness of the proposed control strategy. Yanjun Zhang, Lu Wang, Jun Zhang, and Jianbo Su Copyright © 2016 Yanjun Zhang et al. All rights reserved. Prediction of Collapse Scope of Deep-Buried Tunnels Using Pressure Arch Theory Thu, 21 Jul 2016 09:21:16 +0000 Tunnel collapse remains a serious problem in practice. Effective prediction methods on tunnel collapse are necessary for tunnel engineering. In this study, systematic study on the pressure arch was presented to predict tunnel collapse. Multiple factors under different conditions were considered. First, the pressure arch was described as a certain scope in comparison with the lowest pressure arch line. Then, a deep-buried circular tunnel was selected as the investigated object. Its collapse scope was analyzed using the lowest pressure arch line. Meanwhile, the main influence from the ground stress field was considered. Different modes of ground stress fields were investigated in detail. The results indicate that the collapse scope varies with different ground stress fields. Determination on the collapse scope is strongly affected by the judgment standard of the pressure arch. Furthermore, a selected case was analyzed with the pressure arch. The area and the height of tunnel collapse were calculated with multiple factors, including ground stress field, judgment standard, and lateral pressure coefficient. Finally, selected results were compared with relevant previous researches, and reasonable results were obtained. The present results are helpful for further understanding of the tunnel collapse and could provide suitable guidance for tunnel projects. Yingchao Wang, Hongwen Jing, Qiang Zhang, Ning Luo, and Xin Yin Copyright © 2016 Yingchao Wang et al. All rights reserved. Unsupervised Joint Image Denoising and Active Contour Segmentation in Multidimensional Feature Space Wed, 20 Jul 2016 16:52:41 +0000 We describe a new method for simultaneous image denoising and level set-based active contour segmentation using multidimensional features. We consider an image to be a surface embedded in a Riemannian manifold. By defining a metric in the embedded space, which in our case includes multidimensional image features as well as a level set-based active contour model, a minimization problem in the image space can be obtained through the Polyakov action framework. The resulting minimization problem is solved with a dual algorithm for efficiency. Benefits of this new method include the fact that it is independent of any artificial “running” parameters, and experiments using both synthetic and real images show that the method is robust with respect to noise and blurry object boundaries. Qi Ge, Xiao-Yuan Jing, Fei Wu, Jingjie Yan, and Hai-Bo Li Copyright © 2016 Qi Ge et al. All rights reserved. Energy Efficiency Oriented Design Method of Power Management Strategy for Range-Extended Electric Vehicles Wed, 20 Jul 2016 16:42:20 +0000 The energy efficiency of the range-extended electric bus (REEB) developed by Tsinghua University must be improved; currently, the energy management strategy is a charge-deplete-charge-sustain (CDCS) strategy, which exhibits low energy efficiency on the demonstration model. To improve the energy efficiency and reduce the operating cost, a rule-based control strategy derived from the dynamic programming (DP) strategy is obtained for the Chinese urban bus driving cycle (CUBDC). This rule is extracted by the power-split-ratio (PSR) from the simulation results of the dynamic powertrain model using the DP strategy. By establishing the REEB dynamic models in Matlab/Simulink, the control rule can be achieved, and the power characteristic of powertrain, energy efficiency, operating cost, and computing time are analyzed. The simulation results show that the performance of the rule-based strategy presented in this paper is similar to that of the DP strategy. The energy efficiency can be improved greatly compared with that of the CDCS strategy, and the operating cost can also be reduced. Jiuyu Du, Jingfu Chen, Mingming Gao, and Jia Wang Copyright © 2016 Jiuyu Du et al. All rights reserved. Multidimensional and Interactive Assessment Model of Large-Scale Infrastructure Project and Its Demonstration Based on Double Utility Wed, 20 Jul 2016 14:00:13 +0000 This paper evaluates the project risks with a multidimensional and interactive model from multiagent and utility combination, which takes subjective psychological negative utility into account rather than only focusing on the thinking pattern of objective value loss. Firstly, it analyzes the bodies’ heterogeneous preference and their game behavior using game theory application methods. Secondly, it builds multidimensional and interactive evaluation model of large-scale infrastructure project from many dimensions, such as risk rate, objective utility, and subjective utility. It reflects different values and behavior strategy interdynamic factor in the design of risk utility function. Lastly, it deduces process and approaches of multidimensional and interactive evaluation by typical project. In addition, it tests model parameter with regression analysis. The research of this paper broadens the dimension of project risk evaluation and provides comprehensive and balanced reference for the measure of project risk utility and a better basis for project risk control. Wu Gao, Kairong Hong, and Bin Pan Copyright © 2016 Wu Gao et al. All rights reserved. Flight Tests of Autopilot Integrated with Fault-Tolerant Control of a Small Fixed-Wing UAV Wed, 20 Jul 2016 13:30:19 +0000 A fault-tolerant control scheme for the autopilot of the small fixed-wing UAV is designed and tested by the actual flight experiments. The small fixed-wing UAV called Xiang Fei is developed independently by Nanjing University of Aeronautics and Astronautics. The flight control system is designed based on an open-source autopilot (Pixhawk). Real-time kinematic (RTK) GPS is introduced due to its high accuracy. Some modifications on the longitudinal and lateral guidance laws are achieved to improve the flight control performance. Moreover, a data fusion based fault-tolerant control scheme is integrated in altitude control and speed control for altitude sensor failure and airspeed sensor failure, which are the common problems for small fixed-wing UAV. Finally, the real flight experiments are implemented to test the fault-tolerant control based autopilot of UAV. Real flight test results are given and analyzed in detail, which show that the fixed-wing UAV can track the desired altitude and speed commands during the whole flight process including takeoff, climbing, cruising, gliding, landing, and wave-off by the fault-tolerant control based autopilot. Shuo Wang, Ziyang Zhen, Ju Jiang, and Xinhua Wang Copyright © 2016 Shuo Wang et al. All rights reserved. Simulation Experiment Exploration of Genetic Algorithm’s Convergence over the Relationship Advantage Problem Wed, 20 Jul 2016 11:14:34 +0000 Concentrating on the convergence analysis of Genetic Algorithm (GA), this study originally distinguishes two types of advantage sources: value advantage and relationship advantage. Accordingly, the quantitative feature, complete quantization feature, and the partial quantization feature in the fitness evaluation are proposed. Seven simulation experiments show that these two types of advantages have different convergence properties. For value advantage problems, GA has a good convergence. However, for a relationship advantage problem, only from the practical point of view, it is possible to get a feasible and even satisfactory solution through large-scale searching, but, in theory, however, the searching process is not convergent. Therefore, GA is not reliable to solve relationship advantage problems, to which most engineering problems involving combinatorial optimization belong. This study systematically shows convergence properties of “relationship advantage” through simulation experiments, which will be a new area for the further study on GA. Yabo Luo Copyright © 2016 Yabo Luo. All rights reserved. Research on Preference Polyhedron Model Based Evolutionary Multiobjective Optimization Method for Multilink Transmission Mechanism Conceptual Design Wed, 20 Jul 2016 09:27:20 +0000 To make the optimal design of the multilink transmission mechanism applied in mechanical press, the intelligent optimization techniques are explored in this paper. A preference polyhedron model and new domination relationships evaluation methodology are proposed for the purpose of reaching balance among kinematic performance, dynamic performance, and other performances of the multilink transmission mechanism during the conceptual design phase. Based on the traditional evaluation index of single target of multicriteria design optimization, the robust metrics of the mechanism system and preference metrics of decision-maker are taken into consideration in this preference polyhedron model and reflected by geometrical characteristic of the model. At last, two optimized multilink transmission mechanisms are designed based on the proposed preference polyhedron model with different evolutionary algorithms, and the result verifies the validity of the proposed optimization method. Haihua Zhu, Jun Yang, Weihua Lu, and Jing Li Copyright © 2016 Haihua Zhu et al. All rights reserved. An Efficient Algorithm for Overcomplete Sparsifying Transform Learning with Signal Denoising Tue, 19 Jul 2016 14:24:12 +0000 This paper deals with the problem of overcomplete transform learning. An alternating minimization based procedure is proposed for solving the formulated sparsifying transform learning problem. A closed-form solution is derived for the minimization involved in transform update stage. Compared with existing ones, our proposed algorithm significantly reduces the computation complexity. Experiments and simulations are carried out with synthetic data and real images to demonstrate the superiority of the proposed approach in terms of the averaged representation and denoising errors, the percentage of successful and meaningful recovery of the analysis dictionary, and, more significantly, the computation efficiency. Beiping Hou, Zhihui Zhu, Gang Li, and Aihua Yu Copyright © 2016 Beiping Hou et al. All rights reserved. Determination of Critical Load in a Nonuniform Circular Steel Column under the Eccentric Axial Load Tue, 19 Jul 2016 14:10:33 +0000 The purpose of this paper is to determine a critical load for a nonuniform circular steel tube under eccentrically axial load. The circular tube has variable cross section at flattened ends with existing holes used for connection between members. Three different cases of eccentricities are studied with the drilled holes either on the same side or on the opposite side of column axis. The critical load is calculated from the differential equation of deflection curve which is solved by the power series and Runge-Kutta method. In addition, the loading tests were performed on a total of 180 specimens with different diameters, slenderness, and connection. The calculated results are compared and shown in a good agreement with those obtained from the experimental results. The results also show that the critical load decreases rapidly even at a small value of eccentricity and thus may have a significant effect on the load-carrying capacity. Stanislav Kotšmíd, Chang-Hung Kuo, and Pavel Beňo Copyright © 2016 Stanislav Kotšmíd et al. All rights reserved. Short-Term Wind Speed Forecasting Using the Data Processing Approach and the Support Vector Machine Model Optimized by the Improved Cuckoo Search Parameter Estimation Algorithm Tue, 19 Jul 2016 14:01:29 +0000 Power systems could be at risk when the power-grid collapse accident occurs. As a clean and renewable resource, wind energy plays an increasingly vital role in reducing air pollution and wind power generation becomes an important way to produce electrical power. Therefore, accurate wind power and wind speed forecasting are in need. In this research, a novel short-term wind speed forecasting portfolio has been proposed using the following three procedures: (I) data preprocessing: apart from the regular normalization preprocessing, the data are preprocessed through empirical model decomposition (EMD), which reduces the effect of noise on the wind speed data; (II) artificially intelligent parameter optimization introduction: the unknown parameters in the support vector machine (SVM) model are optimized by the cuckoo search (CS) algorithm; (III) parameter optimization approach modification: an improved parameter optimization approach, called the SDCS model, based on the CS algorithm and the steepest descent (SD) method is proposed. The comparison results show that the simple and effective portfolio EMD-SDCS-SVM produces promising predictions and has better performance than the individual forecasting components, with very small root mean squared errors and mean absolute percentage errors. Chen Wang, Jie Wu, Jianzhou Wang, and Zhongjin Hu Copyright © 2016 Chen Wang et al. All rights reserved. A Joint Modeling Analysis of Passengers’ Intercity Travel Destination and Mode Choices in Yangtze River Delta Megaregion of China Tue, 19 Jul 2016 08:12:35 +0000 Joint destination-mode travel choice models are developed for intercity long-distance travel among sixteen cities in Yangtze River Delta Megaregion of China. The model is developed for all the trips in the sample and also by two different trip purposes, work-related business and personal business trips, to accommodate different time values and attraction factors. A nested logit modeling framework is applied to model trip destination and mode choices in two different levels, where the lower level is a mode choice model and the upper level is a destination choice model. The utility values from various travel modes in the lower level are summarized into a composite utility, which is then specified into the destination choice model as an intercity impedance factor. The model is then applied to predict the change in passenger number from Shanghai to Yangzhou between scenarios with and without high-speed rail service to demonstrate the applicability. It is helpful for understanding and modeling megaregional travel destination and mode choice behaviors in the context of developing country. Yanli Wang, Bing Wu, Zhi Dong, and Xin Ye Copyright © 2016 Yanli Wang et al. All rights reserved.