Mathematical Problems in Engineering The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Numerical Simulation and Experimental Study on Temperature Distribution of Self-Lubricating Packing Rings in Reciprocating Compressors Wed, 28 Sep 2016 15:39:56 +0000 The nonuniform abrasion failure and high-temperature thermal failure of packing rings have a significant influence on compressor reliability, particularly that of oil-free compressors. In this study, a test rig was constructed to measure the dynamic temperature of packing rings under different operational conditions in an oil-free reciprocating compressor. The dynamic axial and radial temperature distributions of the packing rings were obtained using an innovative internal temperature testing device that kept the thermocouples and packing box relatively static during compressor operation. A three-dimensional heat transfer model was also developed to analyze the temperature distribution of the packing boxes, piston rod, and cylinder during such operation. Good agreement was observed between the simulation results and experimental data, which showed an average relative error of less than 2.35%. The results indicate that the pressure ratio exerts a significant effect on the axial temperature distribution and determines which packing ring reaches the maximum temperature. They also show the average temperature to rise with an increase in the rotational speed and to fall with an improvement in the external cooling conditions. Finally, the material of the packing rings was found to affect the temperature gradient from their inner to outer surface. Jia Xiaohan, Zhang Qingqing, Feng Jianmei, and Peng Xueyuan Copyright © 2016 Jia Xiaohan et al. All rights reserved. An Efficient Heuristic Approach for Irregular Cutting Stock Problem in Ship Building Industry Wed, 28 Sep 2016 13:19:42 +0000 This paper presents an efficient approach for solving a real two-dimensional irregular cutting stock problem in ship building industry. Cutting stock problem is a common cutting and packing problem that arises in a variety of industrial applications. A modification of selection heuristic Exact Fit is applied in our research. In the case referring to irregular shapes, a placement heuristics is more important to construct a complete solution. A placement heuristic relating to bottom-left-fill is presented. We evaluate the proposed approach using generated instance only with convex shapes in literatures and some instances with nonconvex shapes based on real problem from ship building industry. The results demonstrate that the effectiveness and efficiency of the proposed approach are significantly better than some conventional heuristics. Yan-xin Xu Copyright © 2016 Yan-xin Xu. All rights reserved. Lineament Length and Density Analyses Based on the Segment Tracing Algorithm: A Case Study of the Gaosong Field in Gejiu Tin Mine, China Wed, 28 Sep 2016 13:17:35 +0000 This study used the Segment Tracing Algorithm (STA) to extract lineaments from remotely sensed images. A computer program was then written to calculate the lineament densities and lengths. In Gaosong field, 3,233 lineaments were extracted based on a 200 m × 200 m grid size. The results indicate that most lineaments lengths are between 30 m and 50 m, and the number of lineaments within each cell ranges from 1 to 6. Areas with high distributions exist on both sides of the central region. According to the contour map of lineament length, the maximum lineament length is 380 m, and the minimum length is 30 m. The contours mainly extend in two directions, including NE and NW trends. This is consistent with the prominent NE and NW strike faults that prevail in the mining area. The results are similar to those obtained in the Machishui ore block, which has become a mine production area. High values of lineament length and density in the contour map of Gaosong field may be associated with hydrothermal tin mineralization in the study area. The results of this study potentially provide a new approach to mineral exploration in the early stage of geological prospecting. Chunzhong Ni, Shitao Zhang, Chunxue Liu, Yongfeng Yan, and Yujian Li Copyright © 2016 Chunzhong Ni et al. All rights reserved. Tracking Control Based on Control Allocation with an Innovative Control Effector Aircraft Application Wed, 28 Sep 2016 13:17:02 +0000 This paper proposes a control allocation method for the tracking control problem of a class of morphing aircraft with special actuators which are different from the conventional actuation surfaces. This design of actuators can bring about some potential advantages to the flight vehicles; however, due to the integral constraints, the desired control cannot be performed accurately; therefore, it leads to undesirable tracking errors, so influencing the performance of the system. Because the system could be control allocated, based on the designed cost function that describes the tracking errors, the cuckoo search algorithm (CSA) is introduced to search for the optimum solution within the calculated actuator execution commands that are equivalent to the desired commands. Several improvement measures are proposed for boosting the efficiency of the CSA and ensuring reasonable solutions. Simulation results show that the proposed control allocation method is necessary and effective, and the improvement measures are helpful in obtaining the optimum solution. Chaoyang Dong, Yao Lu, and Qing Wang Copyright © 2016 Chaoyang Dong et al. All rights reserved. Model and Frequency Control for Three-Phase Wireless Power Transfer System Wed, 28 Sep 2016 11:39:32 +0000 In order to the eliminate the “dead spot” in the traditional three-phase wireless power transfer (WPT) system, a three-phase WPT system with an asymmetric magnetic circuit is presented in this paper. Additionally, mathematical model of the system is established and the system parameters are optimized. Based on the fact that the resonant frequency and efficiency are greatly varied with the load, a method based on impedance conversion is further proposed to improve the frequency stability and system efficiency. Finally, simulation and experimental results show that the proposed method is reliable and feasible to eliminate the “dead spot.” Chenyang Xia, Yuling Liu, Kezhang Lin, and Guangqing Xie Copyright © 2016 Chenyang Xia et al. All rights reserved. Model Building and Optimization Analysis of MDF Continuous Hot-Pressing Process by Neural Network Wed, 28 Sep 2016 11:39:07 +0000 We propose a one-layer neural network for solving a class of constrained optimization problems, which is brought forward from the MDF continuous hot-pressing process. The objective function of the optimization problem is the sum of a nonsmooth convex function and a smooth nonconvex pseudoconvex function, and the feasible set consists of two parts, one is a closed convex subset of , and the other is defined by a class of smooth convex functions. By the theories of smoothing techniques, projection, penalty function, and regularization term, the proposed network is modeled by a differential equation, which can be implemented easily. Without any other condition, we prove the global existence of the solutions of the proposed neural network with any initial point in the closed convex subset. We show that any accumulation point of the solutions of the proposed neural network is not only a feasible point, but also an optimal solution of the considered optimization problem though the objective function is not convex. Numerical experiments on the MDF hot-pressing process including the model building and parameter optimization are tested based on the real data set, which indicate the good performance of the proposed neural network in applications. Qingfa Li, Yaqiu Liu, and Liangkuan Zhu Copyright © 2016 Qingfa Li et al. All rights reserved. Simulation-Based Optimization for Yard Design at Mega Container Terminal under Uncertainty Wed, 28 Sep 2016 10:24:25 +0000 The conventional approach of designing a container yard should be reexamined in the context of sustainable port development. Considering the uncertain future throughput, a simulation-based optimization framework is proposed to obtain a cost-effective and reliable design solution to the physical layout and equipment deployment strategy of the yard at a mega container terminal. In this framework, a two-stage stochastic programming model is presented aided with a simulation procedure of terminal operations. Finally, an application is given and the results show that the proposed integrated decision framework is effective and helpful for optimizing container yard design in the context of sustainable development of container terminals. Yong Zhou, Wenyuan Wang, Xiangqun Song, and Zijian Guo Copyright © 2016 Yong Zhou et al. All rights reserved. A Modified Adaboost Algorithm to Reduce False Positives in Face Detection Wed, 28 Sep 2016 09:41:49 +0000 We present a modified Adaboost algorithm in face detection, which aims at an accurate algorithm to reduce false-positive detection rates. We built a new Adaboost weighting system that considers the total error of weak classifiers and classification probability. The probability was determined by computing both positive and negative classification errors for each weak classifier. The new weighting system gives higher weights to weak classifiers with the best positive classifications, which reduces false positives during detection. Experimental results reveal that the original Adaboost and the proposed method have comparable face detection rate performances, and the false-positive results were reduced almost four times using the proposed method. Cesar Niyomugabo, Hyo-rim Choi, and Tae Yong Kim Copyright © 2016 Cesar Niyomugabo et al. All rights reserved. The Complex Function Method Roadway Section Design of the Soft Coal Seam Wed, 28 Sep 2016 09:29:29 +0000 As for the sophisticated advanced support technique of vertical wall semicircle arch roadway in the three-soft coal seam, a design of flat top U-shape roadway section was put forward. Based on the complex function method, the surrounding rock displacement and stress distribution laws both of vertical wall semicircle arch roadway and of flat top U-shape roadway were obtained. The results showed that the displacement distribution laws in the edge of roadway surrounding rock were similar between the two different roadways and the area of plasticity proportion of flat top U-shape roadway approximately equals that of vertical wall semicircle arch roadway. Based on finite element method, the bearing behaviors of the U-type steel support under the interaction of surrounding rock in vertical wall semicircle arch roadway and flat top U-shape roadway were analyzed. The results showed that, from a mechanics perspective, U-type steel support can fulfill the requirement of surrounding rock supporting in flat top U-shape roadway and vertical wall semicircle arch roadway. The field measurement of mining roadway surrounding rock displacement in Zouzhuang coal mine working face 3204 verified the accuracy of theoretical analysis and numerical simulation. Shihao Tu, Zhaoxin Li, Zhiwei Ye, Cun Zhang, and Lei Zhang Copyright © 2016 Shihao Tu et al. All rights reserved. Subjective Score Predictor: A New Evaluation Function of Distorted Image Quality Wed, 28 Sep 2016 06:10:11 +0000 Image quality assessment (IQA) is a method to evaluate the perceptual performance of image. Many objective IQA algorithms are developed from the objective comparison of image features, which are mainly trained and evaluated from the ground truth of subjective scores. Due to the inconsistent experiment conditions and cumbersome observing processes of subjective experiments, it is imperative to generate the ground truth for IQA research via objective computation methods. In this paper, we propose a subjective score predictor (SSP) aiming to provide the ground truth of IQA datasets. In perfect accord with distortion information, the distortion strength of distorted image is employed as a dependent parameter. To further be consistent with subjective opinion, on the one hand, the subjective score of source image is viewed as a quality base value, and, on the other hand, we integrate the distortion parameter and the quality base value into a human visual model function to obtain the final SSP value. Experimental results demonstrate the advantages of the proposed SSP in the following aspects: effective performance to reflect the distortion strength, competitive ground truth, and valid evaluation for objective IQA methods as well as subjective scores. Xiaoyan Luo, Shining Wang, and Ding Yuan Copyright © 2016 Xiaoyan Luo et al. All rights reserved. An Integrated Optimal Energy Management/Gear-Shifting Strategy for an Electric Continuously Variable Transmission Hybrid Powertrain Using Bacterial Foraging Algorithm Tue, 27 Sep 2016 12:31:11 +0000 This study developed an integrated energy management/gear-shifting strategy by using a bacterial foraging algorithm (BFA) in an engine/motor hybrid powertrain with electric continuously variable transmission. A control-oriented vehicle model was constructed on the Matlab/Simulink platform for further integration with developed control strategies. A baseline control strategy with four modes was developed for comparison with the proposed BFA. The BFA was used with five bacterial populations to search for the optimal gear ratio and power-split ratio for minimizing the cost: the equivalent fuel consumption. Three main procedures were followed: chemotaxis, reproduction, and elimination-dispersal. After the vehicle model was integrated with the vehicle control unit with the BFA, two driving patterns, the New European Driving Cycle and the Federal Test Procedure, were used to evaluate the energy consumption improvement and equivalent fuel consumption compared with the baseline. The results show that and were improved for the optimal energy management and integrated optimization at the first and second driving cycles, respectively. Real-time platform designs and vehicle integration for a dynamometer test will be investigated in the future. Syuan-Yi Chen, Yi-Hsuan Hung, and Chien-Hsun Wu Copyright © 2016 Syuan-Yi Chen et al. All rights reserved. Linearity Identification for General Partial Linear Single-Index Models Tue, 27 Sep 2016 10:00:48 +0000 Partial linear models, a family of popular semiparametric models, provide us with an interpretable and flexible assumption for modelling complex data. One challenging question in partial linear models is the structure identification for the linear components and the nonlinear components, especially for high dimensional data. This paper considers the structure identification problem in the general partial linear single-index models, where the link function is unknown. We propose two penalized methods based on a modern dimension reduction technique. Under certain regularity conditions, we show that the second estimator is able to identify the underlying true model structure correctly. The convergence rate of the new estimator is established as well. Shaogao Lv and Luhong Wang Copyright © 2016 Shaogao Lv and Luhong Wang. All rights reserved. Research on Methods for Discovering and Selecting Cloud Infrastructure Services Based on Feature Modeling Tue, 27 Sep 2016 09:19:22 +0000 Nowadays more and more cloud infrastructure service providers are providing large numbers of service instances which are a combination of diversified resources, such as computing, storage, and network. However, for cloud infrastructure services, the lack of a description standard and the inadequate research of systematic discovery and selection methods have exposed difficulties in discovering and choosing services for users. First, considering the highly configurable properties of a cloud infrastructure service, the feature model method is used to describe such a service. Second, based on the description of the cloud infrastructure service, a systematic discovery and selection method for cloud infrastructure services are proposed. The automatic analysis techniques of the feature model are introduced to verify the model’s validity and to perform the matching of the service and demand models. Finally, we determine the critical decision metrics and their corresponding measurement methods for cloud infrastructure services, where the subjective and objective weighting results are combined to determine the weights of the decision metrics. The best matching instances from various providers are then ranked by their comprehensive evaluations. Experimental results show that the proposed methods can effectively improve the accuracy and efficiency of cloud infrastructure service discovery and selection. Huamin Zhu, Lifa Wu, Kangyu Huang, and Zhenji Zhou Copyright © 2016 Huamin Zhu et al. All rights reserved. Mathematical Models for Dealing with Risk in Engineering Tue, 27 Sep 2016 08:18:27 +0000 Jurgita Antucheviciene, Gang Kou, Vida Maliene, and Egidijus Rytas Vaidogas Copyright © 2016 Jurgita Antucheviciene et al. All rights reserved. PRUB: A Privacy Protection Friend Recommendation System Based on User Behavior Tue, 27 Sep 2016 07:24:02 +0000 The fast developing social network is a double-edged sword. It remains a serious problem to provide users with excellent mobile social network services as well as protecting privacy data. Most popular social applications utilize behavior of users to build connection with people having similar behavior, thus improving user experience. However, many users do not want to share their certain behavioral information to the recommendation system. In this paper, we aim to design a secure friend recommendation system based on the user behavior, called PRUB. The system proposed aims at achieving fine-grained recommendation to friends who share some same characteristics without exposing the actual user behavior. We utilized the anonymous data from a Chinese ISP, which records the user browsing behavior, for 3 months to test our system. The experiment result shows that our system can achieve a remarkable recommendation goal and, at the same time, protect the privacy of the user behavior information. Wei Jiang, Ruijin Wang, Zhiyuan Xu, Yaodong Huang, Shuo Chang, and Zhiguang Qin Copyright © 2016 Wei Jiang et al. All rights reserved. Image Encryption Algorithm Based on Dynamic DNA Coding and Chen’s Hyperchaotic System Tue, 27 Sep 2016 07:04:45 +0000 With the development of national information processes, specific image information from secret departments or individuals is often required to be confidentially transmitted. Numerous image encryption methods exist, especially since the initial value sensitivity and other characteristics of chaos theory and chaos theory-based encryption have become increasingly important in recent years. At present, DNA coding constitutes a new research direction of image encryption that uses the four base pairs of DNA code and image pixel values to establish a special correspondence, in order to achieve pixel diffusion. There are eight DNA encoding rules, and current methods of selecting the DNA encoding rules are largely fixed. Thus, the security of encoded data is not high. In this paper, we use the Lorenz chaotic system, Chen’s hyperchaotic system, and the DNA encoding combination and present a new image encryption algorithm that can dynamically select eight types of DNA encoding rules and eight types of DNA addition and subtraction rules, with significant improvements in security. Through simulation experiments and histograms, correlations, and NPCR analyses, we have determined that the algorithm possesses numerous desirable features, including good encryption effects and antishear and antinoise performances. Jian Zhang, Dezhi Hou, and Honge Ren Copyright © 2016 Jian Zhang et al. All rights reserved. Uncertain Unified Chaotic Systems Control with Input Nonlinearity via Sliding Mode Control Mon, 26 Sep 2016 16:49:52 +0000 This paper studies the stabilization problem for a class of unified chaotic systems subject to uncertainties and input nonlinearity. Based on the sliding mode control theory, we present a new method for the sliding mode controller design and the control law algorithm for such systems. In order to achieve the goal of stabilization unified chaotic systems, the presented controller can make the movement starting from any point in the state space reach the sliding mode in limited time and asymptotically reach the origin along the switching surface. Compared with the existing literature, the controller designed in this paper has many advantages, such as small chattering, good stability, and less conservative. The analysis of the motion equation and the simulation results all demonstrate that the method is effective. Zhi-ping Shen, Jian-dong Xiong, and Yi-lin Wu Copyright © 2016 Zhi-ping Shen et al. All rights reserved. A Control Method to Balance the Efficiency and Reliability of a Time-Delayed Pump-Valve System Mon, 26 Sep 2016 16:41:30 +0000 The efficiency and reliability of pumps are highly related to their operation conditions. The concept of the optimization pump operation conditions is to adjust the operation point of the pump to obtain higher reliability at the cost of lower system efficiency using a joint regulation of valve and frequency convertor. This paper realizes the control of the fluid conveying system based on the optimization results. The system is a nonlinear Multi-Input Multioutput (MIMO) system with time delays. In this paper, the time delays are separated from the system. The delay-free system is linearized using input-output linearization and controlled using a sliding mode method. A modified Smith predictor is used to compensate time delays of the system. The control strategy is validated to be effective on the test bench. The comparison of energy consumption and operation point deviation between conventional speed regulation and the new method is presented. Zhounian Lai, Peng Wu, Shuai Yang, and Dazhuan Wu Copyright © 2016 Zhounian Lai et al. All rights reserved. Modified Limiting Equilibrium Method for Stability Analysis of Stratified Rock Slopes Mon, 26 Sep 2016 14:27:18 +0000 The stratified rock of Jurassic strata is widely distributed in Three Gorges Reservoir Region. The limit equilibrium method is generally utilized in the stability analysis of rock slope with single failure plane. However, the stratified rock slope cannot be accurately estimated by this method because of different bedding planes and their variable shear strength parameters. Based on the idealized model of rock slope with bedding planes, a modified limiting equilibrium method is presented to determine the potential sliding surface and the factor of safety for the stratified rock slope. In this method, the S-curve model is established to define the spatial variations of the shear strength parameters and   of bedding plane and the tensile strength of rock mass. This method was applied in the stability evaluation of typical stratified rock slope in Three Gorges Reservoir Region, China. The result shows that the factor of safety of the case study is 0.973, the critical sliding surface for the potential slip surface appears at bedding plane C, and the tension-controlled failure occurs at 10.5 m to the slope face. Rui Yong, Chang-Dong Li, Jun Ye, Man Huang, and Shigui Du Copyright © 2016 Rui Yong et al. All rights reserved. Optimal Reinsurance Design for Pareto Optimum: From the Perspective of Multiple Reinsurers Mon, 26 Sep 2016 13:35:04 +0000 This paper investigates optimal reinsurance strategies for an insurer which cedes the insured risk to multiple reinsurers. Assume that the insurer and every reinsurer apply the coherent risk measures. Then, we find out the necessary and sufficient conditions for the reinsurance market to achieve Pareto optimum; that is, every ceded-loss function and the retention function are in the form of “multiple layers reinsurance.” Xing Rong and Yunzhou Zhu Copyright © 2016 Xing Rong and Yunzhou Zhu. All rights reserved. A Simplified Kalman Filter for Integrated Navigation System with Low-Dynamic Movement Mon, 26 Sep 2016 13:05:55 +0000 In the integrated navigation system with inertial base, the update frequency of Strapdown Inertial Navigation System (SINS) is always higher than those of aided navigation systems; thus updating inconsistency among subsystems becomes an issue. The analysis indicates that the state transition matrix in Kalman filter is essentially a function of carrier motion. Based on this understanding, a simplified Kalman filter algorithm for integrated navigation is designed for those carriers with low-dynamic motions. With this simplified algorithm, when the filter is without aided information updating, only calculation and accumulation on state transition matrix are executed, and when the filter is with updating, normal time and measurement update are done based on the averaged state transition matrix. Thus the calculation load in the simplified algorithm will be significantly lessened. Furthermore, due to cumulative sum and average operation, more accurate state transition matrix and higher fusion accuracy will arrive for the smoothing effect on random noise of carrier motion parameters. Simulation and test results indicate that when the carrier is with a low-dynamic motion, the simplified algorithm can complete the data fusion of integrated system effectively with reduced computation load and suppressed oscillation amplitude of state vector error. Xixiang Liu, Jian Sima, Yongjiang Huang, Xianjun Liu, and Pan Zhang Copyright © 2016 Xixiang Liu et al. All rights reserved. Stability for a New Class of GNOVI with ()-Weak-GRD Mappings in Positive Hilbert Spaces Mon, 26 Sep 2016 06:51:42 +0000 By using ordered fixed point theory, we set up a new class of GNOVI structures (general nonlinear ordered variational inclusions) with -weak-GRD mappings, discuss an existence theorem of solution, consider a perturbed Ishikawa iterative algorithm and the convergence of iterative sequences generated by the algorithm, and show the stability of algorithm for GNOVI structures in positive Hilbert spaces. The results in the instrument are obtained. Hong Gang Li, Yongqin Yang, Mao Ming Jin, and Qinghua Zhang Copyright © 2016 Hong Gang Li et al. All rights reserved. Online Open Circuit Fault Diagnosis for Rail Transit Traction Converter Based on Object-Oriented Colored Petri Net Topology Reasoning Sun, 25 Sep 2016 13:51:13 +0000 For online open circuit fault diagnosis of the traction converter in rail transit vehicles, conventional approaches depend heavily on component parameters and circuit layouts. For better universality and less parameter sensitivity during the diagnosis, this paper proposes a novel topology analysis approach to diagnose switching device open circuit failures. During the diagnosis, the topology is analyzed with fault reasoning mechanism, which is based on object-oriented Petri net (OOCPN). The OOCPN model takes in digitalized current inputs as fault signatures, and dynamical transitions between discrete switching states of a circuit with broken device are symbolized with the dynamical transitions of colored tokens in OOCPN. Such transitions simulate natural reasoning process of an expert’s brain during diagnosis. The dependence on component parameters and on circuit layouts is finally eliminated by such circuit topology reasoning process. In the last part, the proposed online reasoning and diagnosis process is exemplified with the case of a certain switching device failure in the power circuit of traction converter. Lei Wang, Chunmei Xu, Lijun Diao, Jie Chen, Ruichang Qiu, and Peizhen Wang Copyright © 2016 Lei Wang et al. All rights reserved. Sufficiency and Duality for Multiobjective Programming under New Invexity Sun, 25 Sep 2016 13:38:39 +0000 A class of multiobjective programming problems including inequality constraints is considered. To this aim, some new concepts of generalized -type I and -type II functions are introduced in the differentiable assumption by using the sublinear function . These new functions are used to establish and prove the sufficient optimality conditions for weak efficiency or efficiency of the multiobjective programming problems. Moreover, two kinds of dual models are formulated. The weak dual, strong dual, and strict converse dual results are obtained under the aforesaid functions. Yingchun Zheng and Xiaoyan Gao Copyright © 2016 Yingchun Zheng and Xiaoyan Gao. All rights reserved. Fault Diagnosis for Engine Based on Single-Stage Extreme Learning Machine Sun, 25 Sep 2016 11:34:08 +0000 Single-Stage Extreme Learning Machine (SS-ELM) is presented to dispose of the mechanical fault diagnosis in this paper. Based on it, the traditional mapping type of extreme learning machine (ELM) has been changed and the eigenvectors extracted from signal processing methods are directly regarded as outputs of the network’s hidden layer. Then the uncertainty that training data transformed from the input space to the ELM feature space with the ELM mapping and problem of the selection of the hidden nodes are avoided effectively. The experiment results of diesel engine fault diagnosis show good performance of the SS-ELM algorithm. Fei Gao and Jiangang Lv Copyright © 2016 Fei Gao and Jiangang Lv. All rights reserved. A Novel Three-Dimensional Beamforming Antenna Array for Wireless Power Focusing Sun, 25 Sep 2016 11:25:53 +0000 An antenna array capable of focusing the power transmitted to a specified point in space is modeled and simulated. This array will serve best for wireless power transmission applications where one of the goals is to maximize the power transfer efficiency. The array consists of 100 dipole antennas with each antenna transmitting a sum of 50 signals where each signal has a different frequency. This difference in frequency gives an additional degree of freedom that allows the overall beam pattern to be focused to a point in space instead of just a direction. The same array structure is also capable of transmitting power to multiple points in space which is promising when it comes to powering multiple points of interest. Mohammad A. Safar and Ayman S. Al-Zayed Copyright © 2016 Mohammad A. Safar and Ayman S. Al-Zayed. All rights reserved. Combined Similarity to Reference Image with Joint Sparsifying Transform for Longitudinal Compressive Sensing MRI Sun, 25 Sep 2016 10:17:36 +0000 It is challenging to save acquisition time and reconstruct a medical magnetic resonance (MR) image with important details and features from its compressive measurements. In this paper, a novel method is proposed for longitudinal compressive sensing (LCS) MR imaging (MRI), where the similarity between reference and acquired image is combined with joint sparsifying transform. Furthermore, the joint sparsifying transform with the wavelet and the Contourlet can efficiently represent both isotropic and anisotropic features and the objective function is solved by extended smooth-based monotone version of the fast iterative shrinkage thresholding algorithm (SFISTA). The experiment results demonstrate that the existing regularization model obtains better performance with less acquisition time and recovers both edges and fine details of MR images, much better than the existing regularization model based on the similarity and the wavelet transform for LCS-MRI. Ruirui Kang, Gangrong Qu, Bin Cao, and Long Yan Copyright © 2016 Ruirui Kang et al. All rights reserved. Evaluation, Classification, and Influential Factors Analysis of Traffic Congestion in Chinese Cities Using the Online Map Data Sun, 25 Sep 2016 09:30:11 +0000 This study proposes a new method to describe, compare, and classify the traffic congestion states in 23 Chinese cities using the online map data and further reveals the influential factors that may affect them. First, the real-time traffic congestion information is obtained from the online map of AutoNavi in a 15-minute interval. Next, a new measuring index is introduced to describe the overall characterization of congestion patterns in each city based on online map data, which is named as the congestion ratio. The next analysis is the cluster analysis based on the temporal distribution of the congestion ratio, which helps to identify groups of the selected cities with similar traffic congestion states. These cities are categorized as four groups according to the severity of traffic congestion: severely congested, less severely congested, amble, and smooth cities. Lastly, multiple linear regression models are developed to identify the primary factors that affect the congestion ratio. The result shows that the influences of per capita road area, car ownership, and vehicle miles traveled (VMT) on the congestion ratio are significant. Sensitivity analyses are also implemented in order to reveal more effective policy measures in mitigating traffic congestion in urban areas. Changzhi Bian, Changwei Yuan, Wenbo Kuang, and Dayong Wu Copyright © 2016 Changzhi Bian et al. All rights reserved. Statistical Properties of SNR for Compressed Measurements Sun, 25 Sep 2016 08:29:03 +0000 Some basic statistical properties of the compressed measurements are investigated. It is well known that the statistical properties are a foundation for analyzing the performance of signal detection and the applications of compressed sensing in communication signal processing. Firstly, we discuss the statistical properties of the compressed signal, the compressed noise, and their corresponding energy. And then, the statistical characteristics of SNR of the compressed measurements are calculated, including the mean and the variance. Finally, probability density function and cumulative distribution function of SNR are derived for the cases of the Gamma distribution and the Gaussian distribution. Numerical simulation results demonstrate the correctness of the theoretical analysis. Yulong Gao, Yanping Chen, and Linxiao Su Copyright © 2016 Yulong Gao et al. All rights reserved. Signal Denoising Method Based on Adaptive Redundant Second-Generation Wavelet for Rotating Machinery Fault Diagnosis Sun, 25 Sep 2016 06:51:15 +0000 Vibration signal of rotating machinery is often submerged in a large amount of noise, leading to the decrease of fault diagnosis accuracy. In order to improve the denoising effect of the vibration signal, an adaptive redundant second-generation wavelet (ARSGW) denoising method is proposed. In this method, a new index for denoising result evaluation (IDRE) is constructed first. Then, the maximum value of IDRE and the genetic algorithm are taken as the optimization objective and the optimization algorithm, respectively, to search for the optimal parameters of the ARSGW. The obtained optimal redundant second-generation wavelet (RSGW) is used for vibration signal denoising. After that, features are extracted from the denoised signal and then input into the support vector machine method for fault recognition. The application result indicates that the proposed ARSGW denoising method can effectively improve the accuracy of rotating machinery fault diagnosis. Na Lu, Guangtao Zhang, Yuanchu Cheng, and Diyi Chen Copyright © 2016 Na Lu et al. All rights reserved.