Mathematical Problems in Engineering The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. The Role of High Performance Computing and Communication for Real-Time Biofeedback in Sport Tue, 24 May 2016 12:46:47 +0000 This paper studies the main technological challenges of real-time biofeedback in sport. We identified communication and processing as two main possible obstacles for high performance real-time biofeedback systems. We give special attention to the role of high performance computing with some details on possible usage of DataFlow computing paradigm. Motion tracking systems, in connection with the biomechanical biofeedback, help in accelerating motor learning. Requirements about various parameters important in real-time biofeedback applications are discussed. Inertial sensor tracking system accuracy is tested in comparison with a high performance optical tracking system. Special focus is given on feedback loop delays. Real-time sensor signal acquisitions and real-time processing challenges, in connection with biomechanical biofeedback, are presented. Despite the fact that local processing requires less energy consumption than remote processing, many other limitations, most often the insufficient local processing power, can lead to distributed system as the only possible option. A multiuser signal processing in football match is recognised as an example for high performance application that needs high-speed communication and high performance remote computing. DataFlow computing is found as a good choice for real-time biofeedback systems with large data streams. Anton Umek and Anton Kos Copyright © 2016 Anton Umek and Anton Kos. All rights reserved. A Method to Determine Generalized Basic Probability Assignment in the Open World Tue, 24 May 2016 06:50:51 +0000 Dempster-Shafer evidence theory (D-S theory) has been widely used in many information fusion systems since it was proposed by Dempster and extended by Shafer. However, how to determine the basic probability assignment (BPA), which is the main and first step in D-S theory, is still an open issue, especially when the given environment is in an open world, which means the frame of discernment is incomplete. In this paper, a method to determine generalized basic probability assignment in an open world is proposed. Frame of discernment in an open world is established first, and then the triangular fuzzy number models to identify target in the proposed frame of discernment are established. Pessimistic strategy based on the differentiation degree between model and sample is defined to yield the BPAs for known targets. If the sum of all the BPAs of known targets is over one, then they will be normalized and the BPA of unknown target is assigned to ; otherwise the BPA of unknown target is equal to minus the sum of all the known targets BPAs. IRIS classification examples illustrated the effectiveness of the proposed method. Wen Jiang, Jun Zhan, Deyun Zhou, and Xin Li Copyright © 2016 Wen Jiang et al. All rights reserved. A Protocol for Provably Secure Authentication of a Tiny Entity to a High Performance Computing One Mon, 23 May 2016 13:35:43 +0000 The problem of developing authentication protocols dedicated to a specific scenario where an entity with limited computational capabilities should prove the identity to a computationally powerful Verifier is addressed. An authentication protocol suitable for the considered scenario which jointly employs the learning parity with noise (LPN) problem and a paradigm of random selection is proposed. It is shown that the proposed protocol is secure against active attacking scenarios and so called GRS man-in-the-middle (MIM) attacking scenarios. In comparison with the related previously reported authentication protocols the proposed one provides reduction of the implementation complexity and at least the same level of the cryptographic security. Siniša Tomović, Miodrag J. Mihaljević, Aleksandar Perović, and Zoran Ognjanović Copyright © 2016 Siniša Tomović et al. All rights reserved. Stabilizing Parametric Region of Multiloop PID Controllers for Multivariable Systems Based on Equivalent Transfer Function Mon, 23 May 2016 08:53:50 +0000 The aim of this paper is to determine the stabilizing PID parametric region for multivariable systems. Firstly, a general equivalent transfer function parameterization method is proposed to construct the multiloop equivalent process for multivariable systems. Then, based on the equivalent single loops, a model-based method is presented to derive the stabilizing PID parametric region by using the generalized Hermite-Biehler theorem. By sweeping over the entire ranges of feasible proportional gains and determining the stabilizing regions in the space of integral and derivative gains, the complete set of stabilizing PID controllers can be determined. The robustness of the design procedure against the approximation in getting the SISO plants is analyzed. Finally, simulation of a practical model is carried out to illustrate the effectiveness of the proposed technique. Xiaoli Luan, Qiang Chen, Pedro Albertos, and Fei Liu Copyright © 2016 Xiaoli Luan et al. All rights reserved. Stability and Boundedness of Solutions to Nonautonomous Parabolic Integrodifferential Equations Mon, 23 May 2016 08:00:43 +0000 We consider a class of linear nonautonomous parabolic integrodifferential equations. We will assume that the coefficients are slowly varying in time. Conditions for the boundedness and stability of solutions to the considered equations are suggested. Our results are based on a combined usage of the recent norm estimates for operator functions and theory of equations on the tensor product of Hilbert spaces. Michael Gil' Copyright © 2016 Michael Gil'. All rights reserved. Service and Price Decisions of a Supply Chain with Optional After-Sale Service Sun, 22 May 2016 12:46:09 +0000 For durable products, the high quality after-sales service has been playing an increasingly important role in consumers’ purchase behaviors. We mainly study a supply chain composed of a manufacturer and a retailer. In a process of products sales, the manufacturer will provide a basic free quality assurance service. On this basis, the retailer provides paid optional quality assurance service to consumers to promote sales. Users are divided into two categories in this paper: users with no optional service and users with optional services. We derive the equilibrium decisions between the manufacturer and the retailer under the following two cases: (i) the optional after-sales service level and the wholesale price determined by the manufacturer and the retail price determined by the retailer; (ii) the wholesale price determined by the manufacturer and the optional after-sales service level and the retail price determined by the retailer. Xiaochen Sun, Qingshuai Zhang, and Yancong Zhou Copyright © 2016 Xiaochen Sun et al. All rights reserved. Probabilistic Analysis of Steady-State Temperature and Maximum Frequency of Multicore Processors considering Workload Variation Sun, 22 May 2016 08:50:05 +0000 A probabilistic method is presented to analyze the temperature and the maximum frequency for multicore processors based on consideration of workload variation, in this paper. Firstly, at the microarchitecture level, dynamic powers are modeled as the linear function of IPCs (instructions per cycle), and leakage powers are approximated as the linear function of temperature. Secondly, the microarchitecture-level hotspot temperatures of both active cores and inactive cores are derived as the linear functions of IPCs. The normal probabilistic distribution of hotspot temperatures is derived based on the assumption that IPCs of all cores follow the same normal distribution. Thirdly and lastly, the probabilistic distribution of the set of discrete frequencies is determined. It can be seen from the experimental results that hotspot temperatures of multicore processors are not deterministic and have significant variations, and the number of active cores and running frequency simultaneously determine the probabilistic distribution of hotspot temperatures. The number of active cores not only results in different probabilistic distribution of frequencies, but also leads to different probabilities for triggering DFS (dynamic frequency scaling). Biying Zhang, Zhongchuan Fu, Hongsong Chen, and Gang Cui Copyright © 2016 Biying Zhang et al. All rights reserved. Comparison of the Characteristics of Solid Type and Annular Type Nuclear Fuels Using Thermoelastic-Plastic-Creep FEM Thu, 19 May 2016 16:24:40 +0000 The purpose of this study is to compare the characteristics of two types of nuclear fuel using the finite element program of thermoelastic-plastic-creep analysis. The analyzed fuel rods are of two types, solid and annular ones, and their thermomechanical characteristics are compared. Thermoelastic-plastic-creep analyses were made using an in-house finite element analysis program that adopts the “effective-stress-function” algorithm. The temperature-dependent material properties, which were obtained from the experiments for actual nuclear reactors, are adopted. The effects of type of fuel systems are revealed in both stresses and temperature distributions. The maximum tensile and compressive hoop stress of pellet and cladding are monitored to evaluate the mechanical behavior, and the maximum temperature is used to evaluate the thermal behavior. Although the annular type of fuel has certain disadvantage, it would be used very effectively or safely in future nuclear power plants. Young-Doo Kwon, Dae-Suep Lee, and Tae-Hyeok Yun Copyright © 2016 Young-Doo Kwon et al. All rights reserved. Sourcing for Quality: Cooperating with a Single Supplier or Developing Two Competing Suppliers? Thu, 19 May 2016 12:30:04 +0000 Supplier efforts regarding product quality are an important issue in outsourcing and play a critical role in a manufacturer’s choice of sourcing strategy. Consider a manufacturer that wants to outsource the manufacturing of two substitute products to external suppliers. This paper studies the strategic interactions under two sourcing strategies: single and dual sourcing. A four-stage noncooperative game model is established to describe each member’s decisions. We further propose four decision scenarios: single sourcing with and without manufacturer quality investment sharing and dual sourcing when suppliers cooperate or do not cooperate on quality decisions. By the backward induction approach, we obtain analytical equilibrium solutions for each decision scenario. By comparing each pair of equilibrium profiles, we find that an appropriate proportion of quality investment sharing by the manufacturer can enable a cooperating strategy with a single supplier to be the dominant strategy. When the manufacturer does not want to share or does not want to share a relatively large portion of its supplier’s quality investment, it will always prefer to develop two competing suppliers when the cost of dual sourcing is sufficiently low. However, dual sourcing can be extremely risky for the manufacturer because the suppliers could provide a relatively low product quality level by cooperating on the quality decision to extract the manufacturer’s profit. Jingxian Chen Copyright © 2016 Jingxian Chen. All rights reserved. Computational Modelling of Fracture Propagation in Rocks Using a Coupled Elastic-Plasticity-Damage Model Thu, 19 May 2016 12:05:17 +0000 A coupled elastic-plasticity-damage constitutive model, AK Model, is applied to predict fracture propagation in rocks. The quasi-brittle material model captures anisotropic effects and the distinct behavior of rocks in tension and compression. Calibration of the constitutive model is realized using experimental data for Carrara marble. Through the Weibull distribution function, heterogeneity effect is captured by spatially varying the elastic properties of the rock. Favorable comparison between model predictions and experiments for single-flawed specimens reveal that the AK Model is reliable and accurate for modelling fracture propagation in rocks. Isa Kolo, Rashid K. Abu Al-Rub, and Rita L. Sousa Copyright © 2016 Isa Kolo et al. All rights reserved. An Improved Focused Crawler: Using Web Page Classification and Link Priority Evaluation Thu, 19 May 2016 09:43:45 +0000 A focused crawler is topic-specific and aims selectively to collect web pages that are relevant to a given topic from the Internet. However, the performance of the current focused crawling can easily suffer the impact of the environments of web pages and multiple topic web pages. In the crawling process, a highly relevant region may be ignored owing to the low overall relevance of that page, and anchor text or link-context may misguide crawlers. In order to solve these problems, this paper proposes a new focused crawler. First, we build a web page classifier based on improved term weighting approach (ITFIDF), in order to gain highly relevant web pages. In addition, this paper introduces an evaluation approach of the link, link priority evaluation (LPE), which combines web page content block partition algorithm and the strategy of joint feature evaluation (JFE), to better judge the relevance between URLs on the web page and the given topic. The experimental results demonstrate that the classifier using ITFIDF outperforms TFIDF, and our focused crawler is superior to other focused crawlers based on breadth-first, best-first, anchor text only, link-context only, and content block partition in terms of harvest rate and target recall. In conclusion, our methods are significant and effective for focused crawler. Houqing Lu, Donghui Zhan, Lei Zhou, and Dengchao He Copyright © 2016 Houqing Lu et al. All rights reserved. Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading Thu, 19 May 2016 08:08:43 +0000 The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation analysis of stone column composite foundation. Based on the principle that the vertical load applied on the composite foundation is shared by the stone column and the surrounding soil, the governing solutions for the stone column composite foundation under a multistage load are established. By virtue of the separation of variables, the corresponding solutions of degree of consolidation for loading stage and maintaining load stage are derived separately. According to the Carrillo theorem, the solution for the average total degree of consolidation of entire composite foundation is also obtained. Finally, the reasonableness of the present solution has been verified by comparing the consolidation curve calculated by the present solution with that measured by site test. Shenggen Huang, Yingtao Feng, Hao Liu, Wenbing Wu, and Guoxiong Mei Copyright © 2016 Shenggen Huang et al. All rights reserved. Neutrosophic Functions of the Joint Roughness Coefficient and the Shear Strength: A Case Study from the Pyroclastic Rock Mass in Shaoxing City, China Wed, 18 May 2016 14:03:48 +0000 Many studies have been carried out to investigate the scale effect on the shear behavior of rock joints. However, existing methods are difficult to determinate the joint roughness coefficient (JRC) and the shear strength of rock joints with incomplete and indeterminate information; the nature of scale dependency of rock joints is still unknown and remains an ongoing debate. Thus, this paper establishes two neutrosophic functions of the JRC values and the shear strength based on neutrosophic theory to express and handle the incomplete and indeterminate problems in the analyses of the JRC and the shear strength. An example, including four rock joint samples derived from the pyroclastic rock mass in Shaoxing city, China, is provided to show the effectiveness and rationality of the developed method. The experimental results demonstrate that the proposed neutrosophic functions can express and deal with the incomplete and indeterminate problems of the test data caused by geometry complexity of the rock joint surface and sampling bias. They provide a new approach for estimating the JRC values of the different-sized test profiles and the peak shear strength of rock joints. Jun Ye, Rui Yong, Qi-Feng Liang, Man Huang, and Shi-Gui Du Copyright © 2016 Jun Ye et al. All rights reserved. Multiresolution Time-Domain Scheme for Terminal Response of Two-Conductor Transmission Lines Wed, 18 May 2016 12:00:53 +0000 This paper derives a multiresolution time-domain (MRTD) scheme for the two-conductor lossless transmission line equations based on Daubechies’ scaling functions. And a method is proposed to generate the scheme at the terminal and near the terminal of the lines. The stability and numerical dispersion of this scheme are studied, and the proposed scheme shows a better dispersion property than the conventional FDTD method. Then the MRTD scheme is extended to the two-conductor lossy transmission line equations. The MRTD scheme is implemented with different basis functions for both lossless and lossy transmission lines. Numerical results show that the MRTD schemes which use the scaling functions with high vanishing moment obtain more accurate results. Zongliang Tong, Lei Sun, Ying Li, and Jianshu Luo Copyright © 2016 Zongliang Tong et al. All rights reserved. A Hybrid Algorithm Based on Optimal Quadratic Spline Collocation and Parareal Deferred Correction for Parabolic PDEs Wed, 18 May 2016 10:40:42 +0000 Parareal is a kind of time parallel numerical methods for time-dependent systems. In this paper, we consider a general linear parabolic PDE, use optimal quadratic spline collocation (QSC) method for the space discretization, and proceed with the parareal technique on the time domain. Meanwhile, deferred correction technique is also used to improve the accuracy during the iterations. In fact, the optimal QSC method is a correction of general QSC method. Along the temporal direction we embed the iterations of deferred correction into parareal to construct a hybrid method, parareal deferred correction (PDC) method. The error estimation is presented and the stability is analyzed. To save computational cost, we find out a simple way to balance the two kinds of iterations as much as possible. We also argue that the hybrid algorithm has better system efficiency and costs less running time. Numerical experiments by multicore computers are attached to exhibit the effectiveness of the hybrid algorithm. Jun Liu, Yan Wang, and Rongjian Li Copyright © 2016 Jun Liu et al. All rights reserved. Face Stability Analysis of Shield Tunnels in Homogeneous Soil Overlaid by Multilayered Cohesive-Frictional Soils Wed, 18 May 2016 08:16:18 +0000 In order to better interpret failure features of the failure of soil in front of tunnel face, a new three-dimensional failure mechanism is proposed to analyze the limit support pressure of the tunnel face in multilayered cohesive-frictional soils. The new failure mechanism is composed of two truncated cones that represent the shear failure band and a distributed force acting on the truncated cones that represents the pressure arch effect. By introducing the concept of Terzaghi earth pressure theory, approximation of limit support pressures is calculated using the limit analysis methods. Then the limit support pressures obtained from the new failure mechanism and the existing approaches are compared, which show that the results obtained from the new mechanism in this paper provide relatively satisfactory results. Kaihang Han, Chengping Zhang, Wei Li, and Caixia Guo Copyright © 2016 Kaihang Han et al. All rights reserved. Fractional Differentiation-Based Active Contour Model Driven by Local Intensity Fitting Energy Wed, 18 May 2016 07:51:37 +0000 A novel active contour model is proposed for segmentation images with inhomogeneity. Firstly, fractional order filter is defined by eight convolution masks corresponding to the image orientation in the eight compass directions. Then, the fractional order differentiation image is obtained and applied to the level set method. Secondly, we defined a new energy functional based on local image information and fractional order differentiation image; the proposed model not only can describe the input image more accurately but also can deal with intensity inhomogeneity. Local fitting term can enhance the ability of the model to deal with intensity inhomogeneity. The defined penalty term is used to reduce the occurrence of false boundaries. Finally, in order to eliminate the time-consuming step of reinitialization and ensure stable evolution of level set function, the Gaussian filtering method is used. Experiments on synthetic and real images show that the proposed model is efficient for images with intensity inhomogeneity and flexible to initial contour. Ming Gu and Renfang Wang Copyright © 2016 Ming Gu and Renfang Wang. All rights reserved. Energy Optimization for Distributed Energy Resources Scheduling with Enhancements in Voltage Stability Margin Wed, 18 May 2016 06:43:38 +0000 The need for developing new methodologies in order to improve power system stability has increased due to the recent growth of distributed energy resources. In this paper, the inclusion of a voltage stability index in distributed energy resources scheduling is proposed. Two techniques were used to evaluate the resulting multiobjective optimization problem: the sum-weighted Pareto front and an adapted goal programming methodology. With this new methodology, the system operators can consider both the costs and voltage stability. Priority can be assigned to one objective function according to the operating scenario. Additionally, it is possible to evaluate the impact of the distributed generation and the electric vehicles in the management of voltage stability in the future electric networks. One detailed case study considering a distribution network with high penetration of distributed energy resources is presented to analyse the proposed methodology. Additionally, the methodology is tested in a real distribution network. Hugo Morais, Tiago Sousa, Angel Perez, Hjörtur Jóhannsson, and Zita Vale Copyright © 2016 Hugo Morais et al. All rights reserved. A Multicriteria Approach for the Optimal Location of Gasoline Stations Being Transformed as Self-Service in Taiwan Tue, 17 May 2016 14:17:47 +0000 Location selection significantly influences business success. In particular, location selection for the fuel stations is characterized by constraints on investment in facilities and by criteria that involve a series of social utilities. Recently, a leading fuel company in Taiwan initiated transforming its traditional gas stations into self-service. However, it is difficult to select an existing station to be transformed as self-service because there are many conflicting goals in the problem of location selection. In this paper, we apply a multicriteria approach, integrating analytic hierarchy process (AHP) and multichoice goal programming (MCGP), to obtain an appropriate gas station from many alternative locations that best suit the preferences of decision-makers in the case company. This study incorporates the weights obtained from AHP to set multiple aspirations in MCGP for ranking each candidate location. The results show that, under multiple quantitative and qualitative factors in the selection process, our proposed model is more scientific and efficient than unaided methods in finding a suitable location within a shorter evaluation time. Sheng-Pen Wang, Hsing-Chen Lee, and Yu-Kuang Hsieh Copyright © 2016 Sheng-Pen Wang et al. All rights reserved. Dynamic Environmental/Economic Scheduling for Microgrid Using Improved MOEA/D-M2M Tue, 17 May 2016 13:29:34 +0000 The environmental/economic dynamic scheduling for microgrids (MGs) is a complex multiobjective optimization problem, which usually has dynamic system parameters and constraints. In this paper, a biobjective optimization model of MG scheduling is established. And various types of microsources (like the conventional sources, various types of renewable sources, etc.), electricity markets, and dynamic constraints are considered. A recently proposed MOEA/D-M2M framework is improved (I-MOEA/D-M2M) to solve the real-world MG scheduling problems. In order to deal with the constraints, the processes of solutions sorting and selecting in the original MOEA/D-M2M are revised. In addition, a self-adaptive decomposition strategy and a modified allocation method of individuals are introduced to enhance the capability of dealing with uncertainties, as well as reduce unnecessary computational work in practice and meet the time requirements for the dynamic optimization tasks. Thereafter, the proposed I-MOEA/D-M2M is applied to the independent MG scheduling problems, taking into account the load demand variation and the electricity price changes. The simulation results by MATLAB show that the proposed method can achieve better distributed fronts in much less running time than the typical multiobjective evolutionary algorithms (MOEAs) like the improved strength Pareto evolutionary algorithm (SPEA2) and the nondominated sorting genetic algorithm II (NSGAII). Finally, I-MOEA/D-M2M is used to solve a 24-hour MG dynamic operation scheduling problem and obtains satisfactory results. Xin Li and Yanjun Fang Copyright © 2016 Xin Li and Yanjun Fang. All rights reserved. Synchronization between Different Networks with Time-Varying Delay and Its Application in Bilayer Coupled Public Traffic Network Tue, 17 May 2016 08:38:44 +0000 In order to study the dynamic characteristics of urban public traffic network, this paper establishes the conventional bus traffic network and the urban rail traffic network based on the space modeling method. Then regarding these two networks as the subnetwork, the paper presents a new bilayer coupled public traffic network through the transfer relationship between subway and bus, and this model well reflects the connection between the passengers and bus operating vehicles. Based on the synchronization theory of coupling network with time-varying delay and taking “Lorenz system” as the network node, the paper studies the synchronization of bilayer coupled public traffic network. Finally, numerical results are given to show the impact of public traffic dispatching, delayed departure, the number of public bus stops between bus lines, and the number of transfer stations between two traffic modes on the bilayer coupled public traffic network balance through Matlab simulation. Wenju Du, Jiangang Zhang, Yinzhen Li, and Shuang Qin Copyright © 2016 Wenju Du et al. All rights reserved. Failure Propagation Modeling and Analysis via System Interfaces Tue, 17 May 2016 07:26:50 +0000 Safety-critical systems must be shown to be acceptably safe to deploy and use in their operational environment. One of the key concerns of developing safety-critical systems is to understand how the system behaves in the presence of failures, regardless of whether that failure is triggered by the external environment or caused by internal errors. Safety assessment at the early stages of system development involves analysis of potential failures and their consequences. Increasingly, for complex systems, model-based safety assessment is becoming more widely used. In this paper we propose an approach for safety analysis based on system interface models. By extending interaction models on the system interface level with failure modes as well as relevant portions of the physical system to be controlled, automated support could be provided for much of the failure analysis. We focus on fault modeling and on how to compute minimal cut sets. Particularly, we explore state space reconstruction strategy and bounded searching technique to reduce the number of states that need to be analyzed, which remarkably improves the efficiency of cut sets searching algorithm. Lin Zhao, Krishnaiyan Thulasiraman, Xiaocheng Ge, and Ru Niu Copyright © 2016 Lin Zhao et al. All rights reserved. Algorithm for Target Recognition Based on Interval-Valued Intuitionistic Fuzzy Sets with Grey Correlation Tue, 17 May 2016 06:01:28 +0000 In order to improve exact recognition ratios for aerial targets, this paper presents a novel algorithm for target recognition based on interval-valued intuitionistic fuzzy sets with grey correlation. Drawbacks of some previously proposed methods are analyzed, and then a novel algorithm is presented. Recognition matrix of an aerial target is established first. Every entry associated with the matrix is an interval-valued intuitionistic fuzzy number, which is composed of interval-valued membership and nonmembership, representing the relation of the target to one category in terms of one characteristic parameter. Then grey correlation theory is used to analyze the recognition matrix to obtain the grey correlation degree of this unknown target to every category. 200 sets of target recognition data are used to compare the proposed algorithm with traditional methods. Experimental results verify that the correct recognition ratio can be up to 99.5% that satisfies the expectations, which shows the proposed algorithm can solve the target recognition problems better. The proposed algorithm can be used to solve the uncertain inference problems, such as target recognition, threat assessment, and decision making. Xuan Huang, Lihong Guo, Jiang Li, and Yang Yu Copyright © 2016 Xuan Huang et al. All rights reserved. A Data-Flow Soft-Core Processor for Accelerating Scientific Calculation on FPGAs Mon, 16 May 2016 13:28:30 +0000 We present a new type of soft-core processor called the “Data-Flow Soft-Core” that can be implemented through FPGA technology with adequate interconnect resources. This processor provides data processing based on data-flow instructions rather than control flow instructions. As a result, during an execution on the accelerator of the Data-Flow Soft-Core, both partial data and instructions are eliminated as traffic for load and store activities. Data-flow instructions serve to describe a program and to dynamically change the context of a data-flow program graph inside the accelerator, on-the-fly. Our proposed design aims at combining the performance of a fine-grained data-flow architecture with the flexibility of reconfiguration, without requiring a partial reconfiguration or new bit-stream for reprogramming it. The potential of the data-flow implementation of a function or functional program can be exploited simply by relying on its description through the data-flow instructions that reprogram the Data-Flow Soft-Core. Moreover, the data streaming process will mirror those present in other FPGA applications. Finally, we show the advantages of this approach by presenting two test cases and providing the quantitative and numerical results of our evaluations. Lorenzo Verdoscia and Roberto Giorgi Copyright © 2016 Lorenzo Verdoscia and Roberto Giorgi. All rights reserved. Cloud Model-Based Method for Infrared Image Thresholding Mon, 16 May 2016 09:01:10 +0000 Traditional statistical thresholding methods, directly constructing the optimal threshold criterion using the class variance, have certain versatility but lack the specificity of practical application in some cases. To select the optimal threshold for infrared image thresholding, a simple and efficient method based on cloud model is proposed. The method firstly generates the cloud models corresponding to image background and object, respectively, and defines a novel threshold dependence criterion related with the hyper-entropy of these cloud models and then determines the optimal grayscale threshold by the minimization of this criterion. It is indicated by the experiments that, compared with selected methods, using both image thresholding and target detection, the proposed method is suitable for infrared image thresholding since it performs good results and is reasonable and effective. Tao Wu, Rui Hou, and Yixiang Chen Copyright © 2016 Tao Wu et al. All rights reserved. Analyzing Chaos Systems and Fine Spectrum Sensing Using Detrended Fluctuation Analysis Algorithm Mon, 16 May 2016 07:02:55 +0000 A numerical study that uses detrended fluctuation analysis (DFA) algorithm of time series obtained from linear and nonlinear dynamical systems is presented. The DFA algorithm behavior toward periodic and chaotic signals is investigated and the effect of the time scale under analysis is discussed. The displayed results prove that the DFA algorithm response is invariant (stable performance) to initial condition and chaotic system parameters. An initial idea of DFA algorithm implementation for fine spectrum sensing (SS) is proposed under two-stage spectrum sensor approach with test statistics based on the scaling exponent value. The outcomes demonstrate a promising new SS technique that can alleviate several imperfections such as noise power uncertainty and spatial correlation between the adjacent antenna array elements. Javier S. González-Salas, Modar S. Shbat, Francisco C. Ordaz-Salazar, and Jorge Simón Copyright © 2016 Javier S. González-Salas et al. All rights reserved. Characterization of Rock Mechanical Properties Using Lab Tests and Numerical Interpretation Model of Well Logs Mon, 16 May 2016 06:18:35 +0000 The tight gas reservoir in the fifth member of the Xujiahe formation contains heterogeneous interlayers of sandstone and shale that are low in both porosity and permeability. Elastic characteristics of sandstone and shale are analyzed in this study based on petrophysics tests. The tests indicate that sandstone and mudstone samples have different stress-strain relationships. The rock tends to exhibit elastic-plastic deformation. The compressive strength correlates with confinement pressure and elastic modulus. The results based on thin-bed log interpretation match dynamic Young’s modulus and Poisson’s ratio predicted by theory. The compressive strength is calculated from density, elastic impedance, and clay contents. The tensile strength is calibrated using compressive strength. Shear strength is calculated with an empirical formula. Finally, log interpretation of rock mechanical properties is performed on the fifth member of the Xujiahe formation. Natural fractures in downhole cores and rock microscopic failure in the samples in the cross section demonstrate that tensile fractures were primarily observed in sandstone, and shear fractures can be observed in both mudstone and sandstone. Based on different elasticity and plasticity of different rocks, as well as the characteristics of natural fractures, a fracture propagation model was built. Hao Xu, Wen Zhou, Runcheng Xie, Lina Da, Christopher Xiao, Yuming Shan, and Haotian Zhang Copyright © 2016 Hao Xu et al. All rights reserved. Eigenfunction Expansions for the Stokes Flow Operators in the Inverted Oblate Coordinate System Mon, 16 May 2016 06:03:49 +0000 When studying axisymmetric particle fluid flows, a scalar function, , is usually employed, which is called a stream function. It serves as a velocity potential and it can be used for the derivation of significant hydrodynamic quantities. The governing equation is a fourth-order partial differential equation; namely, , where is the Stokes irrotational operator and is the Stokes bistream operator. As it is already known, in some axisymmetric coordinate systems, such as the cylindrical, spherical, and spheroidal ones, separates variables, while in the inverted prolate spheroidal coordinate system, this equation accepts -separable solutions, as it was shown recently by the authors. Notably, the kernel space of the operator does not decompose in a similar way, since it accepts separable solutions in cylindrical and spherical system of coordinates, while semiseparates variables in the spheroidal coordinate systems and it -semiseparates variables in the inverted prolate spheroidal coordinates. In addition to these results, we show in the present work that in the inverted oblate spheroidal coordinates, the equation also -separates variables and we derive the eigenfunctions of the Stokes operator in this particular coordinate system. Furthermore, we demonstrate that the equation   -semiseparates variables. Since the generalized eigenfunctions of cannot be obtained in a closed form, we present a methodology through which we can derive the complete set of the generalized eigenfunctions of in the modified inverted oblate spheroidal coordinate system. Maria Hadjinicolaou and Eleftherios Protopapas Copyright © 2016 Maria Hadjinicolaou and Eleftherios Protopapas. All rights reserved. Measurement and Prediction Method of Compressibility Factor at High Temperature and High Pressure Sun, 15 May 2016 11:20:52 +0000 In order to get the compressibility factor of working fluid under different conditions, experimental measurement method of under high pressure and high temperature and data mining method were studied in this paper. Experimental measurement method based on real gas state equation and prediction method based on Least Squares Support Vector Machine were proposed. First, an experimental method for measuring at high temperature and high pressure was designed; in this method the temperature, pressure, and density (mass and volume) of corresponding state were measured and substituted into the actual gas equation of state, and then can be calculated. Meanwhile, in order to obtain continuous value in plane, Squares Support Vector Machines are introduced to establish the prediction model of . Take Hexamethyldisiloxane, for example; the experimental data of was obtained using the experimental method. Meanwhile the prediction model of , which can be used as calculation function of , was established based on those experimental data, and the (: 500 K~800 K, : 1.3 MPa~2.25 MPa) was calculated by using this calculation function. By comparison with this published data, it was found that the average relative error was 2.14%. Xiaoxun Zhu, Bochao Xu, and Zhonghe Han Copyright © 2016 Xiaoxun Zhu et al. All rights reserved. Voltage Balancing Method on Expert System for 51-Level MMC in High Voltage Direct Current Transmission Sun, 15 May 2016 08:09:59 +0000 The Modular Multilevel Converters (MMC) have been a spotlight for the high voltage and high power transmission systems. In the VSC-HVDC (High Voltage Direct Current based on Voltage Source Converter) transmission system, the energy of DC link is stored in the distributed capacitors, and the difference of capacitors in parameters and charge rates causes capacitor voltage balance which affects the safety and stability of HVDC system. A method of MMC based on the expert system for reducing the frequency of the submodules (SMs) of the IGBT switching frequency is proposed. Firstly, MMC with 51 levels for HVDC is designed. Secondly, the nearest level control (NLC) for 51-level MMC is introduced. Thirdly, a modified capacitor voltage balancing method based on expert system for MMC-based HVDC transmission system is proposed. Finally, a simulation platform for 51-level Modular Multilevel Converter is constructed by using MATLAB/SIMULINK. The results indicate that the strategy proposed reduces the switching frequency on the premise of keeping submodule voltage basically identical, which greatly reduces the power losses for MMC-HVDC system. Yong Chen and Xu Zhang Copyright © 2016 Yong Chen and Xu Zhang. All rights reserved.