Search

Abstract: This paper proposes a developed bi-objective two-stage stochastic mixed-integer linear programming model for redesigning a reliable warehouse network. In this model, the warehouses capacity which should be phased out, remained, or relocated to other warehouses, and the shipment quantity of the product between the network nodes with a consideration for two delivery lead times is to be determined. Unlike most previous works, considering two delivery lead times, the maximum capacity for each warehouse location, reliability and uncertainty are taken into account in this study. The proposed bi-objective model includes: (1) minimizing average costs including the sum of fixed, production, transportation, relocation and capacity extension costs; (2) maximizing the coverage percentage of customer demand delivered within the preferred delivery lead time. In order to obtain Pareto optimal solutions, a novel version of -constraint method (i.e., the augmented -constraint) is applied. A real industrial case is applied to validate and verify the developed warehouse redesigning network model under reliability concept. [Copyright &y& Elsevier]

Abstract: In this paper, we consider two iterative algorithms for the Sylvester-conjugate matrix equation and . When these two matrix equations are consistent, for any initial matrices the solutions can be obtained within finite iterative steps in the absence of round off errors. Some lemmas and theorems are stated and proved where the iterative solutions are obtained. Two numerical examples are given to illustrate the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: In view that the selections of box tap and thread making parameters are still groundless and lack scientific evidence, which has caused many practical engineering problems, such as long fishing cycle and low success rate, this study establishes a mathematical model such that fish is fished by the box tap based on the theory of large deformation and principle of virtual work. The analysis and evaluation methods of the whole elastoplasticity process for tapping and fishing are proposed as well in accordance with Johnson and Cook’s experimental model and separation criterion in our study. In addition, the effects of such factors (drilling pressure, rotation speed, box tap strength, taper and pitch) on the thread making capacity of the box tap and the new thread strength of fish have been systemically analyzed. In the case study, the paper derives the safety rotation speed range of tapping, the optimal box tap tape and parameter combination of fishing, and the maximum allowable lifting power. The results obtained in our study show that the analyzing model and evaluation methods are quite reasonable and can be generally applied, which will be of great significance for the enhancement of fishing efficiency in future industry. [Copyright &y& Elsevier]

Abstract: RFID readers for passive tags suffer from reader-to-reader interference. Mathematical models of reader-to-reader interference can be categorized into single interference and additive interference models. Although it considers only the direct collisions between two readers, the single interference model is commonly adopted since it allows faster simulations. However, the additive interference model is more realistic since it captures the total interference from several readers. In this paper, an analysis of the two models is presented and a comparison between them is conducted according to several evaluation scenarios. Besides, the impact of the different parameters, including path loss exponent, SIR/SINR threshold and noise power, is evaluated for the two models. [Copyright &y& Elsevier]

Abstract: During the fast developing process of the Chinese economy, China consumes lots of energy and environmental pollution caused by energy consumption currently urgently needs solving. So, paying more attention to energy saving and emission reduction is very important. Therefore, to reasonably allocate resources and reduce emissions in China’s different regions has practical significance. So this paper firstly considers the model construction method for resource allocation considering undesirable outputs between different decision making units based on the DEA framework under the CRS and VRS assumption. We have proposed some resource allocation models as a multiple objective linear problem which considers the input reduction, desirable output reduction and undesirable output reduction. Then, to demonstrate the practical application of the resource allocation model, numerical examples are used to illustrate the approach. In addition, we explore the resource allocation problem of China’s regions in 2006–2010. The empirical results show that the resource allocation models dealing with undesirable outputs have effective configuration results, that is, the reduction proportion for desirable output is smaller than the reduction proportion for undesirable output. From the resource allocation results in China’s regions, we find that the eastern area has more emission reduction than the central and western areas corresponding to the same energy consumption reduction, and the energy and environmental policy should focus more on the central and western areas. All of these conclusions will give some policy recommendations on saving energy and reducing pollution emissions. [Copyright &y& Elsevier]

Abstract: To achieve rapid and precise diagnosis of crop diseases, an active and dynamic method of diagnosis of crop diseases is needed and such a method is proposed in this paper. This method adopts Bayesian networks to represent the relationships among the symptoms and crop diseases. This method has two main differences from the existing diagnosis methods. First, it does not use all the symptoms in the diagnosis, but purposively selects a subset of symptoms which are the most relevant to diagnosis; the active symptom selection is based on the concept of a Markov blanket in a Bayesian network. Second, a specific incremental learning algorithm for Bayesian networks is also proposed to make the diagnosis model update dynamically over time in order to adapt to temporal changes of environment. Furthermore, the diagnosis results can be calculated without inference in Bayesian networks, so the method has low time complexity. Theoretical analysis and experimental results demonstrate that the proposed method can significantly enhance the performance of crop disease diagnosis. [Copyright &y& Elsevier]

Abstract: This paper theoretically analyzes the quality changes of aquatic products by the temperature environments according to the types of temperature fluctuations. First the temperature fluctuation is divided into three types of temperature environments for discussion during the transportation in the aquatic cold chain, by which the temperature model is put forward for each type. And then quality evaluation models are established respectively for the three temperature fluctuating environments. Finally, experiments are given, which show the effectiveness of the models. [Copyright &y& Elsevier]

Abstract: In this paper, we model and computationally investigate the effect of spin–orbit interaction on the electron energy spectra for nanoscale semiconductor quantum rings. Our three-dimensional mathematical model considers the effective one-electron band Hamiltonian, the energy- and position-dependent electron effective mass approximation, and the spin-dependent Ben Daniel–Duke boundary conditions. The nonlinear iterative method is applied to solve the corresponding nonlinear eigenvalue problem, which converges monotonically for all energy states. Physically, it is found that the spin-dependent boundary conditions lead to a spin-splitting of the electron energy states with non-zero angular momentum in nanoscale InAs/GaAs quantum rings. The spin-splitting is strongly dependent upon the dimension of the explored quantum ring and is dominated by the inner radius, the base radius, and the height of the quantum ring. Under zero magnetic fields, the spin-splitting energy is decreased when the radius is increased. Meanwhile, it is greater than that of the InAs/GaAs quantum dot and demonstrates an experimentally measurable quantity (up to 2 meV) for relatively small semiconductor quantum rings. [Copyright &y& Elsevier]

Abstract: This paper introduces a discrete-time self-exciting threshold binomial model to price derivative securities. The key idea is to incorporate the regime switching effect in a discrete-time binomial model for an asset’s prices via the “self-exciting” threshold principle. The proposed model provides a simple structure for pricing options in a changing economic environment. Numerical examples for the proposed threshold binomial model as well as their trinomial extension are given. [Copyright &y& Elsevier]

Abstract: Many spectrum usage measurement reports have shown that the fixed-frequency allocation mechanism causes unbalanced resource occupancy. Most of the current devices are constrained, preventing their performance from being optimized. This paper proposes the MHC-MAC protocol. It has asynchronous assembly line mode cognitive MAC aimed at improving the HC-MAC protocol performance with low throughput and channel utilization rate. From the sensing time, task number, licensed channel number and data packet length aspects, mathematical model and program simulation results are presented to demonstrate that MHC-MAC is better than HC-MAC in spectrum utilization and network capacity. [Copyright &y& Elsevier]

Abstract: In this paper, on the basis of Newton’s method, we propose a fast quasilinearization numerical scheme, coupled with Rothe’s method, for fully nonlinear parabolic equations. General conditions that provide quadratic, uniform and monotone convergence of the quasilinearization method (QLM) of solving fully nonlinear ordinary differential equations that arise on each time level, are formulated and elaborated. The convergence of QLM and its rate are examined numerically, on a simple test example with an exact solution. The first few iterations already provide extremely accurate and stable numerical results. The second goal is to consider three applications of the proposed schemes in financial mathematics. Namely, numerical results for three nonlinear problems of optimal investment are presented and discussed. The numerical experiments of the last problem are based on the data from statistic information of the Bulgarian National Bank and Bratislava Interbank. [Copyright &y& Elsevier]

Abstract: In this paper we study the transport of a reactive solute through a thin (or long) cylindrical pipe filled with micropolar fluid. We suppose that the solute particles undergo a first-order chemical reaction at the lateral boundary of the pipe. The effective model for solute concentration is derived by means of a formal asymptotic analysis with respect to the pipe’s thickness. The asymptotic approximation is built, showing explicitly the effects of fluid microstructure and chemical reaction on the solute dispersion. [Copyright &y& Elsevier]

Abstract: Design errors leading to rework and/or design changes are considered to be the primary contributor to schedule delays and cost overruns in design and construction projects. While design errors are deemed prevalent, most design and construction firms do not measure the number of errors they create, thereby having limited knowledge regarding their mechanism to undermine project performance. To address this, a system dynamics model has been developed to capture the dynamics of design errors and systematically assess their negative impacts. This paper reports on the development of the model, and its application to a university building project. The results indicate that design errors can significantly delay project schedule in spite of continuous schedule recovery actions taken by construction managers. The case study also shows that schedule pressure can propagate the negative impact of design errors to numerous construction activities, including those that are not directly associated with the errors. Finally, the case study confirms that the developed model can more rigorously assess the negative impact of design errors, which is often underestimated by practitioners. Based on these results, it is concluded that the developed model can assist project managers in better understanding the dynamics of design errors and recovering delayed schedule, particularly under schedule pressure. [Copyright &y& Elsevier]

Abstract: The new Spanish regulations allow wind farms to go to the market to sell the energy generated by their facilities. In the case of over- or under-supply, other producers must reduce or increase their production to resolve the so-called deviation, thereby incurring financial losses. Faced with this situation, wind farms have several options. In this paper we consider one promising method: the combined optimization of a pumped-storage hydro-plant and a wind park. First, we are going to present the mathematical modelling of the resulting problem. Second, we shall solve the optimization problem using Optimal Control techniques and finally we shall present several examples of the combined optimization and analyse which strategy is the best one possible. [Copyright &y& Elsevier]

Abstract: Deformable models are mathematical tools which are able to emulate physical characteristics of objects in image processing. In the original formulation, 1D and 2D models are defined in the spatial domain. These models use the finite element method (FEM) for the spatial discretization. Subsequent work proposes a frequency-based approach of the deformable models, also based on the FEM, which leads to a simple formulation and design. The Fourier-based approach offers important computational savings. In addition, each frequency component of the model acts as a system which is independent of the rest of components. This allows us to generalize the formulation of multidimensional deformable models, which are presented in this paper using -spline as shape function for the FEM. This process allows us to obtain a computationally efficient iterative system in matrix form, suitable for models of any number of dimensions. These models can be used for fast segmentation and tracking of 2D and 3D objects with non-rigid motion or deformation. Other applications such as simulation of soft-tissue deformation are also feasible. [Copyright &y& Elsevier]

Abstract: In this paper we present a new framework to identify leaders in a Social Network Site using the Personalized PageRank vector. The methodology is based on the concept of Leadership group recently introduced by one of the authors. We show how to analyze the structure of the Leadership group as a function of a single parameter. Zachary’s network and a Facebook university network are used to illustrate the applicability of the model. [Copyright &y& Elsevier]

Abstract: Pharmacokinetic models are of utmost importance in drug and medical research. The class of parallel inputs models consists of two or more linear chains connected together in parallel. It has been used to represent pharmacokinetic processes in which the input shows effects on the output with different delays in time. Due to physiological variability, the exact values of the model parameters are uncertain, but they can be bounded by intervals. In this case, the computation of output bounds can be posed as the solution of an initial value problem (IVP) for ordinary differential equations (ODEs) with uncertain initial conditions. However, current methods may produce a significant overestimation. In this paper, a new method to minimise overestimation when using the parallel inputs model is proposed and applied to two cases: subcutaneous insulin absorption for artificial pancreas research, and the study of the double-peak phenomenon observed for certain drugs. Our proposal consists in performing a model reduction in conjunction with analytical solutions of the input chains and a monotonicity analysis of model states and parameters. This method allows obtaining tighter output bounds with low computational cost compared to the latest techniques. [Copyright &y& Elsevier]

Abstract: Evidence shows that divorces are related to the economy and social contagion, as well as to the existence of a difference in happiness between the couple. This paper deals with the mathematical modeling of divorce propagation allowing the estimation of the future divorced population. We use a coupled discrete linear-quadratic difference system model and data collected from the Spanish Statistics Institute (INE). A sensitivity analysis of the growth of the divorced population with respect to the contagion rate is included, and several different economic scenarios are considered. [Copyright &y& Elsevier]

Abstract: Anxiolytics (AX) are the psychotropic drugs prescribed for the treatment of anxiety and insomnia for 2–4 weeks, for longer periods of consumption (>1 month) may lead to the development of tolerance or addiction. In fact, its prescription was 16% of the total pharmaceutical expenditure in Spain in 2007. This paper deals with the development of a mathematical model describing the dynamic of the addiction to AX for the case study of the Spanish region of Castellón. The reasons believed to cause the development of addicts to AX are the economic situation, the marriage termination and the social contact. The simulations performed to forecast the addicts rate for the period 2010–2014 showed an increase from 6% in 2010 to 14% in 2014 with a fluctuation of about 2% between the possible economic scenarios. Finally, the analysis of sensitivity of the rate of addicts to the fluctuation of the social contact parameters was performed, letting us estimate its impact on the pharmaceutical expenditure. [Copyright &y& Elsevier]

Abstract: Conductivity of non-overlapping disks embedded in a two-dimensional background can be investigated by the method of images which is based on the successive application of the inversions with respect to circles. For closely placed disks, the classical method of images yields slowly convergent series. The method of images can be treated as an application of successive approximations to a system of functional equations. In this paper, modified functional equations are deduced to essentially accelerate the convergence. [Copyright &y& Elsevier]

Abstract: In this paper, we study the structure of time scales under translations. We define several kinds of time scales such as the two-way translation invariant time scale and investigate their properties. Then we develop the almost periodic function theory on time scales, with examples given along the way. [Copyright &y& Elsevier]

Abstract: A nonautonomous two dimensional competitive Lotka–Volterra system is considered in this paper. Average conditions on the coefficients are given to guarantee the principle of competitive exclusion in the system. It is shown that our results are extensions of those of the counterpart of periodic system. [Copyright &y& Elsevier]

Abstract: In this paper, we study the ruin problem of a renewal risk process with two-sided jumps. We first derive a defective renewal equation for the ruin probability, then based on the defective renewal equation we give the asymptotic results for the probability of ruin when the claim sizes have a distribution that belongs to with . [Copyright &y& Elsevier]

Abstract: This paper shows that every well-defined solution of the difference equation , where is eventually periodic with period two. [Copyright &y& Elsevier]

Abstract: Let denote the class of functions analytic and univalent in the unit disk normalized such that . In this article the authors discuss the radius of univalence of when and belong to certain subsets of . The paper concludes with the following conjecture. If , then is univalent for and the number cannot improved. The conjecture is shown to be true for some subclasses of , e.g. the class of starlike functions, and the class consisting of functions satisfying the functional inequality Some other related results are also presented. [Copyright &y& Elsevier]

Abstract: Most of the publications regarding the maximal covering location problem (MCLP) address the case where the decision is to be made for one period. In this paper, we deal with a rather untouched version of MCLP which is called dynamic MCLP (DMCLP). In order to solve this problem, a simulated annealing (SA) has been presented. The proposed solution algorithm is capable of solving problems with up to 2500 demand nodes and 200 potential facilities with a fair amount of exactness. Our experiments showed that the proposed approach finds solutions with errors less than one percent. [Copyright &y& Elsevier]

Abstract: In growing competitive markets, close cooperative strategies among the vendors and the buyers are essential to cut the joint inventory cost and to have less response time to the supply chain players. Recently, Yang et al. (2007) [2] have presented an integrated two-stage production–inventory model and used the classical differential calculus method to derive the optimal lot size for the vendor and the buyer, and the number of deliveries in supply chain. Moreover, numerous researchers adopted other algebraic methods to derive the optimal solution for inventory models. However, in these papers, the cost comparisons method and arithmetic–geometric mean inequality do not focus on explicitly developing the mathematical expressions for two-stage inventory system with the backorders. In this study, we extend the inventory model proposed by Yang et al. (2007) [2], and consider a three-variable inventory problem and present an alternative approach to determine the optimal replenishment policy for the integrated vendor–buyer inventory system with backordering utilizing the cost-difference rate comparison approach. [Copyright &y& Elsevier]

Abstract: A stochastic Gilpin–Ayala predator–prey model with time-dependent delay is studied in this paper. We establish sufficient conditions for the existence of a global positive solution of the considered system. Then, we prove stochastically ultimate boundededness and obtain certain asymptotic results regarding the long-time behavior of trajectories of the solution. Also, sufficient criteria for extinction of species for a special case of the considered system are given. At the end, numerical simulations are carried out to support our results. [Copyright &y& Elsevier]

Abstract: The split feasibility problem models inverse problems arising from phase retrieval problems and the intensity modulated radiation therapy. In this paper, two methods have been presented for solving the split feasibility problem. The strong convergence results of presented algorithms have been obtained under some mild conditions. Especially, the minimum norm solution of the split feasibility problem can be found. [Copyright &y& Elsevier]

Abstract: Cam-modulated linkages that can achieve superior kinematic performance as compared with pure linkages have been widely applied in a variety of automation machinery. The tolerance analysis and synthesis are thus quite essential in the design and manufacture of precision cam-modulated linkages. This paper presents comprehensive and systematic mathematical tools for dealing with the tolerance analysis and synthesis of cam-modulated linkages. Based on the concept of equivalent linkage and the derived correlation between the radial-dimension errors and the normal-direction errors of the cam profile, the sensitivity analysis method for equivalent linkages is introduced for analyzing the tolerances in cam-modulated linkages, whose output error equations can be derived through an analytical means. Then, by incorporating the sensitivity analysis method and the concept of design for manufacturing and assembly (DFMA), an optimization model for synthesizing the tolerances in cam-modulated linkages is developed. The objective of this optimization model is to maximize the manufacturability and assembility of a cam-modulated linkage while maintaining acceptable kinematic accuracy of its output motion. A practical case study of analyzing and synthesizing the tolerances in a cam-modulated linkage type pick-and-place device is then performed to illustrate the presented methods. It shows that the mathematical tools presented can be helpful to the design and manufacture of precision cam-modulated linkages. [Copyright &y& Elsevier]

Abstract: A graph is -ordered if for every sequence of distinct vertices of , there exists a cycle in containing these vertices in the specified order. It is -ordered-Hamiltonian if, in addition, the required cycle is a Hamiltonian cycle in . The question of the existence of an infinite class of 3-regular 4-ordered-Hamiltonian graphs was posed in Ng and Schultz in 1997 [2]. At the time, the only known examples of such graphs were and . Some progress was made by Mészáros in 2008 [21] when the Petersen graph was found to be 4-ordered and the Heawood graph was proved to be 4-ordered-Hamiltonian; moreover, an infinite class of 3-regular 4-ordered graphs was found. In 2010, a subclass of the generalized Petersen graphs was shown to be 4-ordered in Hsu et al. [9], with an infinite subset of this subclass being 4-ordered-Hamiltonian, thus answering the open question. However, these graphs are bipartite. In this paper we extend the result to another subclass of the generalized Petersen graphs. In particular, we find the first class of infinite non-bipartite graphs that are both -ordered-Hamiltonian and -ordered-Hamiltonian-connected, which can be seen as a solution to an extension of the question posted in Ng and Schultz in 1997 [2]. (A graph is -ordered-Hamiltonian-connected if for every sequence of distinct vertices of , there exists a Hamiltonian path in from to where these vertices appear in the specified order.) [Copyright &y& Elsevier]

Abstract: Identity-based signcryption (IBSC) is a cryptographic primitive which combines both the functions of identity-based signature and identity-based encryption in a single logical step, but with the cost of computation and communication significantly less than those needed by the signature-then-encryption approach. The first proposal Yu et al. (2009) [12] for IBSC schemes without random oracles and its improvement Zhang (2010) [15] were found insecure. Recently Li and Takagi (2011) [16] presented an improved IBSC, but at the price of large signcryptext expansion and more exponentiation computation. In this paper we reconsider the first (but insecure) IBSC proposal, and find that a small modification will result in a secure IBSC. Unlike that of Li and Takagi, our scheme does not sacrifice the bandwidth and computation efficiency to achieve the security goals. We use the proof techniques of Li and Takagi to prove in the standard model its indistinguishability against adaptive chosen ciphertext attack and existential unforgeability against adaptive chosen message attack. Through comparison of computational cost and communication overhead, our scheme is amongst the most efficient IBSC schemes without random oracles. [Copyright &y& Elsevier]

Abstract: This paper presents a model for the budget-constrained dynamic (multi-period) uncapacitated facility location–network design problem (DUFLNDP). This problem is concerned with the determination of the optimal locations of facilities and the design of the underlying network simultaneously in which there is a budget constraint on investment for opening the facilities and constructing (activating) links for each time period during the planning horizon. The objective is to minimize the total travel costs for customers and operating costs for facilities and network links. Furthermore, a greedy heuristic and a fix-and-optimize heuristic based on simulated annealing and exact methods (Branch & Bound and cutting methods) are proposed to solve the model. The performance of the proposed algorithms were tested on extensive randomly generated instances and compared with the CPLEX solver. The budget-constrained DU FLNDP has a lot of important applications which as one of them, the accessibility of health care facilities in Illam Province of Iran is investigated. [Copyright &y& Elsevier]

Abstract: Two-sided assembly line is a set of sequential workstations where task operations can be performed in two sides of the line. The line is important for large-sized products, such as trucks, buses and cars. In this paper, we proposed a mathematical model for two-sided assembly line type II (TALBP-II) with assignment restrictions. The aim of the model is minimizing the cycle time for a given number of mated-workstations and balancing the workstation simultaneously. The model provides a more realistic situation of the two-sided assembly line problems. Genetic algorithm and iterative first-fit rule are used to solve the problem. The performances of both methods are compared using six numerical examples. Based on the experiments, the iterative first-fit rule can take the advantage of finding the best position over many workstations and the genetic algorithm provides more flexible task assignment and is significantly faster than the iterative first-fit rule. [Copyright &y& Elsevier]

Abstract: The paper presents a simplified mathematical model of a two-leg walking robot with four degrees of freedom. It presents a novel method of sensing and balancing for the bipedal robot with the minimum possible number of degrees of freedom for the walk. The proposed method involves the design of a semi-rigid ankle to facilitate fast and accurate measurements of the sideways (sagittal) instability of the walking robot. The use of a new hip-mass carrying strategy in the forward direction and a system of two counter-masses for the sideways body balancing enables us to decouple the forward walking algorithms from the robot stability issues. The system of two different masses helps to improve the response time and efficiency of the balancing system. The control algorithms developed provide continuous stability of the robot while it walks in a forward direction by actuating its four DC motors. Smooth leg trajectory planning is implemented to minimize the foot–ground impact and jerky motions at the joints. The efficiency of the proposed control algorithms is tested and verified by using MATLAB Simulink computer tools. [Copyright &y& Elsevier]

Abstract: This article is about heat transport limitation standard-used construction wick heat pipes with various working fluids operating at temperatures from −30 °C to 140 °C. In this paper is the proposal and verification of a mathematical model for calculating heat transport limitations of heat pipe. The calculations of the various variants of the wick structure of heat pipe and working fluid are presented in diagrams as a dependency of the heat transport limitations on the working temperature. In the conclusion, the effect of these limits on the cooling power of the heat pipe is evaluated. [Copyright &y& Elsevier]

Abstract: This research deals with the utilization of analytic programming for a synthesis of control law for three selected discrete chaotic systems. The novelty of the approach is that a tool for symbolic regression–analytic programming–is used for such kinds of difficult problems. The paper consists of the descriptions of analytic programming as well as chaotic systems and used cost functions. For simulations, evolutionary algorithm SOMA (Self-Organizing Migrating Algorithm) and analytic programming were used. For each case study, repeated simulations were conducted to outline the effectiveness and robustness of used methods. All repeated simulations have given satisfactory results. [Copyright &y& Elsevier]

Abstract: This paper discusses the possibility of using evolutionary algorithms for the reconstruction of chaotic systems. The main aim of this work is to show that evolutionary algorithms are capable of the reconstruction of chaotic systems without any partial knowledge of internal structure, i.e. based only on measured data and a predefined set of basic mathematical “objects”. Algorithm SOMA and differential evolution were used in reported experiments here. Systems selected for numerical experiments here is the well-known Lorenz system, Simplest Quadratic Flow, Double Sroll, Damped Driven Pendulum and Nosé—Hoover oscillator. For each algorithm repeated simulations were done, totaling 20 simulations. According to obtained results it can be stated that evolutionary reconstruction is an alternative and promising way as to how to identify chaotic systems. [Copyright &y& Elsevier]

Abstract: In this paper, a relatively recent method, namely the differential transform method, is applied to devise a simple scheme for the determination of Laplace transforms. The approach exhibits simplicity in that, unlike the usual method which necessitates integration, it only entails easy differentiation and a few elementary operations. Illustrative examples are provided to demonstrate the applicability and efficiency of the technique. [Copyright &y& Elsevier]

Abstract: In this paper, we consider the application of the empirical likelihood method to the generalized random coefficient autoregressive (GRCA) model. The empirical log-likelihood ratio statistics are proposed and the nonparametric versions of the Wilk’s theorem are obtained. Furthermore, when the order of the model is 1, we also derive a test statistic to test the stationary–ergodicity based on the conditional least-squares method. Numerical results from simulation studies suggest that the empirical likelihood method is more accurate than the normal approximation-based method of Hwang and Basawa (1998) . Some simulation studies are also conducted to investigate the finite sample performances of the proposed test. [Copyright &y& Elsevier]

Abstract: Computer hardware components are susceptible to soft errors which could result in incorrect program execution with improvement of semiconductor technology. To measure the reliability of hardware components, it is important to know the effect of soft error on program outcome. This paper analyzes the effects of soft errors on the level of the program. We choose an approach which combines a high level with a low level to model the program. According to the behaviors of soft errors on hardware components during the instruction pipeline, we build a soft error model. Based on our program model and soft error model, the effect of soft errors on the whole computing program is explored from the granularity of the function. Furthermore, data flow errors and control flow errors which are two main implicit program errors caused by soft errors are analyzed respectively. Based on our analyses, we give a method to estimate the Architectural Vulnerability Factor (AVF) of hardware components statically. Our experiments illustrate this method and indicate our analysis results that there are different program behaviors under the effects of soft errors, especially the ability for the program to mask program errors which are caused by soft errors. [Copyright &y& Elsevier]

Abstract: Many practical control systems can be modeled as switched linear systems with stabilizable and unstabilizable subsystems. In this paper, control synthesis for such a class of systems with actuator saturation is well investigated in the continuous-time and discrete-time cases. Based on the time-dependent switching signals and multiple Lyapunov function method, stabilization conditions are established in terms of LMIs. To obtain an attractive region as large as possible, the optimization problems are formulated. As the applications, the asynchronously switched control and intermittent control under actuator saturation are discussed. Numerical examples and simulations are presented to illustrate the feasibility and values of the proposed results. [Copyright &y& Elsevier]

Abstract: The estimation of groundwater evapotranspiration (ET) helps evaluate the risk of soil salinisation and the capacity of regional water resources. This paper focused on the effect of discretisation cell size on the output uncertainty of regional groundwater evapotranspiration modelling. The study area, the Liuyuankou Irrigation System (LIS), was discretised into cell sizes of 100×100 m, 200×200 m, 500×500 m, 1000×1000 m, and 2000×2000 m. Digital elevation models (DEM) at the lower resolutions were obtained by resampling the 90 m Shuttle Radar Topography Mission (SRTM) DEM using an averaging algorithm. The krigged groundwater table was subtracted from the ground surface elevation to generate the groundwater depth maps for various cell sizes. For each resolution, the groundwater ET was calculated using two ET functions (linear and exponential) for each cell. Lastly, the effects of the cell size on the output of the regional groundwater ET modelling were evaluated. The results showed that lower ET rates were obtained when a coarser cell size was used due to the smothering of the surface elevations and the groundwater depths, regardless of the employed ET functions. From comparisons of the delineated area, the cell numbers, the groundwater depth maps and the simulated groundwater ET rates, a discretisation cell size of 500 m was recommended for the LIS to balance the model’s accuracy and computation efficiency in groundwater ET modelling. [Copyright &y& Elsevier]

Abstract: The basic EOQ/EPQ inventory models with backorders have been developed from different perspectives by several researchers. However, the arguments to locate and guarantee the optimal solution are not complete. This paper presents a complete and analytic solution procedure to the EOQ/EPQ inventory models with linear and fixed backorder costs to locate and ensure the optimal solutions. First, the sufficient and necessary conditions for the existences of the optimal solution are developed. Second, in the case if these conditions are not satisfied, then also the optimal solutions are identified for this situation. The final results are two lemmas and four useful theorems to obtain the optimal solutions to both inventory problems. [Copyright &y& Elsevier]

Abstract: In this paper, the existence of an almost periodic solution for an impulsive two-species logarithmic population model with time-varying delay is established. [Copyright &y& Elsevier]

Abstract: Programmable Logic Controllers (PLC) are widely used in industry. Reliable PLC systems are vital to many critical applications. The reliability analysis of PLC is special because the hardware component and embedded software are combined and operated in a specific manner. This paper presents a probabilistic modeling for PLC systems, which considers both the hardware and software components. Three analysis strategies are proposed for probabilistic evaluation of reliability characterization. The first method is an input-based analysis which considers the impact of errors from primary inputs. The second one is an action-based analysis. It extends the first method by considering the impact of software-based processing deviations on primary inputs. The third method is an action-traverse analysis. It computes the reliability characterization in a single topological traverse through the primary inputs during the software execution. Experimental results demonstrate the effectiveness of our approaches when compared to fault tree analysis. [Copyright &y& Elsevier]

Abstract: PLC is widely used in the field of automatic control. To use formal methods to verify the correctness of PLC programs, semantic characterization of PLC programs are needed. Based on the extended -calculus definition, this paper presents a novel semantic modeling of PLC programs. The results lay the solid underpinnings for theorem proving and modeling checking for PLC systems. [Copyright &y& Elsevier]

Abstract: Most End-Stage Renal Disease (ESRD) patients receiving dialysis therapy are in a state of constant metabolic acidosis which is associated with high cardiovascular morbidity and mortality. In an attempt to improve the quality and efficacy of ESRD patients suffering from acidosis many experimental approaches have been used to investigate acid–base balance during dialysis sessions. However, these experimental approaches are expensive and time consuming. To reduce acidosis morbidity, a compartmental mathematical model is used in this paper. The model takes into account the exchange of small solutes, bicarbonate (HCO3 −) and carbon dioxide, across a non-uniform trans-membrane dialyzer. Blood and dialysate flows are simulated using the Navier–Stokes and Darcy equations respectively. Since the trans-membrane (TM) flux would not be uniform, both blood- and dialysate-side equations are coupled with interfacial conditions calculated by Kedem–Katchalsky equations. Numerical results and clinical data are in close agreement within a satisfactory range, thus confirming that mathematical models can predict dialysis operative parameters with accuracy. Numerical results also confirm that acid–base balance for ESRD patients can be achieved during HCO3 − dialysis therapy. Thus, the model quantifies adequate choice of bicarbonate and electrolyte concentrations to help improve acid–base status of ESRD patients suffering from acidosis. As an investigative framework, the model can also provide a clear insight into other small solute exchanges across the dialyzer membrane. [Copyright &y& Elsevier]

Abstract: In this paper, we introduce a new (combined) integer-valued autoregressive model of order with geometric marginal distributions, denoted by CGINAR(), using the negative binomial thinning introduced by Ristić et al. . Several properties of the model are constructed and discussed, including one-step ahead conditional statistical measures. Some methods for estimating the model parameters are considered and the asymptotic properties of the obtained estimators are derived. A real-life data example is investigated to assess the performance of the model. [Copyright &y& Elsevier]

Abstract: This paper presents a new efficient sequential algorithm for computer modelling of the motion behaviours of molecular dynamical systems. The method is based on the frozen lightly-excited degrees of freedom of an atom in a molecular system, such as inter-atomic oscillations and rotation about double bonds with high frequencies, so that a reduced molecular system with rigid subsets and joints is formed. Then Kane’s dynamical equations and the internal coordinate method (ICM) are applied to the reduced model for recursive formation and solution of equations of motion of the atomistic molecular system. The increased computational efficiency is accomplished through three sequential computing sweepings along the structure of the molecular system so that the equations of motion are solved when they are being formed at a fixed computing cost. The algorithm provides a sequential computational performance for a molecular system with an open-loop structure. Here is the total number of subsets. [Copyright &y& Elsevier]