重大事故规避的危险品运输车辆路径优化研究

基于重大事故规避的思想,建立以最大事故后果最小及运输成本最小为双目标,且事故后果基于实时装载量的危险品运输车辆路径优化模型。基于ε-约束法,设计可求得帕累托最优解的精确算法,该算法包含通过性质求ε下界、规避被支配解的预处理及不可行路径禁止约束3处改进。进一步设计处理大规模问题的多项式时间近似算法,并分析了算法的近似比。最后通过算例对模型和算法进行测试,并通过出灵敏度分析给出管理启示。     

一个新的线性规划无人工变量算法

本文研究了线性规划的求解问题.利用对偶转化的方法,获得了一个计算效率高的新的无人工变量通用算法.该新算法比最近提出的无人工变量算法push-to-pull算法效率更高.     

Optimal control laws for traffic flow

Optimal “on–off” laws for the traffic signals are developed based on the bilinear control problem with the binary constraints. A Lyapunov function based feedback law for regulating traffic congestions is developed. Also, a real-time optimal signal law is developed using a novel binary optimization method. Both methods are tested and compared, and our tests demonstrate that the both methods provide very effective and efficient traffic control laws.     

Inventory returns and special sales in a lot-size system with constant rate of deterioration

The problem of returning or of selling the inventory excess to optimal stock level is considered for deteriorating items. Two inventory models, viz. the infinite and the finite horizon models, are developed, in which the deterioration is assumed to be a constant fraction of the on hand inventory. Both the models are developed under the assumptions of instantaneous delivery and no shortages. When there is no deterioration, the developed models are related to the corresponding inventory models for non-deteriorating items. Examples are given to illustrate the derived results.     

A review of methods and algorithms for optimizing construction scheduling

Optimizing construction project scheduling has received a considerable amount of attention over the past 20 years. As a result, a plethora of methods and algorithms have been developed to address specific scenarios or problems. A review of the methods and algorithms that have been developed to examine the area of construction schedule optimization (CSO) is undertaken. The developed algorithms for solving the CSO problem can be classified into three methods: mathematical, heuristic and metaheuristic. The application of these methods to various scheduling problems is discussed and implications for future research are identified.     

梯级水库群防洪系统多目标决策的灰色优选

将传统的优化技术与新发展起来的灰关联决策理论有机地结合起来,针对洪水调度的特点,提出了一个切实可行的梯级水库群洪水调度方案决策的灰色优选模型.最后,以乌江流域4个梯级电站的洪水调度方案优选进行了说明.     

Neuro-fuzzy technique for navigation of multiple mobile robots

In this paper, navigation techniques for several mobile robots are investigated in a totally unknown environment. In the beginning, Fuzzy logic controllers (FLC) using different membership functions are developed and used to navigate mobile robots. First a fuzzy controller has been used with four types of input members, two types of output members and three parameters each. Next two types of fuzzy controllers have been developed having same input members and output members with five parameters each. Each robot has an array of sensors for measuring the distances of obstacles around it and an image sensor for detecting the bearing of the target. It is found that the FLC having Gaussian membership function is best suitable for navigation of multiple mobile robots. Then a hybrid neuro-fuzzy technique has been designed for the same problem. The neuro-fuzzy technique being used here comprises a neural network, which is acting as a pre processor for a fuzzy controller. The neural network considered for neuro-fuzzy technique is a multi-layer perceptron, with two hidden layers. These techniques have been demonstrated in simulation mode, which depicts that the robots are able to avoid obstacles and reach the targets efficiently. Amongst the techniques developed neuro-fuzzy technique is found to be most efficient for mobile robots navigation. Experimental verifications have been done with the simulation results to prove the authenticity of the developed neuro-fuzzy technique.     

Separable programming/duality approach to solving the multi-product Newsboy/Gardener Problem with linear constraints

The Gardener Problem is an extension of the multi-product Newsboy Problem with constraints. It deals with situations where not only the demand is random but also the yield (the supply). Separable programming and duality approaches are utilized to solve the constrained Newsboy/Gardener Problem. The solution methodologies are developed for the common probability distribution functions for the demand, and uniform distribution for the supply, rendering exact and approximate solutions to the problem. Numerical examples are given and when applicable, the performance of the developed approach is compared to those of existing works in this arena. The results reveal that the developed solution methods efficiently converge to the optimal or near optimum solutions. Also, a salient feature of the proposed methodologies is that they can utilize readily available commercial software to solve the considered problems. This feature facilitates the portability of the developed models to the classroom environment.     

Comments on “Model for cover cracking due to corrosion expansion and uniform stresses at infinity”

This paper presents a discussion on a model for cover cracking due to corrosion expansion and uniform stress at infinity developed by Li et al. [Shu-cai Li, Ming-bin Wang, Shu-chen Li, Model for cover cracking due to corrosion expansion and uniform stresses at infinity, Appl. Math. Modell., doi:10.1016/j.apm.2007.06.003]. The model for cover cracking by the authors uses an equation of the penetration depth of corrosion with time developed from the Faraday’s Law. It is however shown in the discussion that the equation of the penetration depth due to corrosion developed by Li et al. is incorrect. Consequently other equations developed by Li et al. to model cover cracking that use the equation of penetration depth are also incorrect.     

Development of the Kriging Method with Application

This paper describes a modification of the kriging method for working with the square root transformation of a spatial random process. We have developed this method for the situation where the spatial process observed is not supposed to be stationary but the assumption is that its square root is a second order stationary spatial random process. Consequently this method is developed for estimating the integral of the process observed and finally some application of the method is given to data from an environmental radioactivity survey.     

Polynomials orthogonal with respect to cardinal B-spline weight functions

A stable and efficient discretization procedure is developed to compute the recurrence coefficients for orthogonal polynomials whose weight function is a polynomial cardinal spline of order m ≥ 1. The procedure is compared with a symbolic moment-based method developed recently by G. V. Milovanovi?. Numerical examples are provided for illustration.     

Bibliographie zur geometrischen optimierung

A probabilistic scheduling period inventory system is considered for items that deteriorate continuously in time. The demand is assumed to occur instantaneously at the beginning of the scheduling period. Shortages are not allowed. A model with a non-zero lead time is developed first and, then, its special case is considered in which the lead time is a multiple of the scheduling period. The inventory models are developed using a general deterioration function. Their particular cases, when the rate of deterioration is constant, are also developed. Numerical examples are given to illustrate the models.     

随机中立型泛函微分方程的稳定性态

给出了一类中立型随机泛函方程的随机一致稳定性的充分条件,利用了新的分析技巧处理中立型时滞项,得到了中立型随机时滞泛函微分方程渐近稳定性的充分判据.在处理各种渐近估计是有效的.     

Applying GIS and Combinatorial Optimization to Fiber Deployment Plans

A decision-support system for the Fiber Deployment Plan problem is developed for the telephone cable network design in the telecommunications industry. The system employs a Geographic Information System (GIS) and uses combinatorial optimization techniques as its components. A mathematical combinatorial optimization model is formulated for the problem and a heuristic solution procedure is developed for the model. A GIS within the ESRI Arc/INFO and ArcView environment is used to provide data needed to build the mathematical combinatorial optimization model and to furnish an interface between the users and computers in data input and in solution result display. Combinatorial optimization techniques are used in the heuristic solution procedure to find good solutions for the optimization model. The developed decision-support system has been used to real life problems and has resulted in tremendous improvements in the telephone cable network design process. The user is completely satisfied with the performance of the system.     

Cyclic Scheduling for a Multi-product,Single-facility Production System Operating Under a Just-in-time Delivery Policy

Sarker and Parija have developed a model for obtaining the optimal batch size for a single-product manufacturing system operating under a fixed-quantity, periodic delivery policy. In this work, the model is extended to a multi-product situation and a single-facility scheduling scheme is developed for the system. Two situations are considered—one with fixed setup cost and the other with variable setup cost. It is observed that setup cost variability is beneficial to the system under certain conditions.     

A theory for nonlinear soft webs

In this paper, a fundamental theory for deformable webs not resisting any compressive membrane forces is developed through a direct derivation on the deformed configuration. In order to better describe the deformable webs, the classification of deformable webs is presented. A theory for the non-continuum elastic network webs consisting of many deformable cables is presented from the deformable cable theory, and then a theory for fabric deformable webs without relative sliding is developed as well. Finally, a nonlinear theory for continuous deformable webs is presented on the deformed configuration. The local criteria for the existence of such deformable webs are presented through the definitions, and such criteria are very significant for the wrinkling stability of the deformable webs. A deformable web possessing the local wrinkling is an unsolved problem in numerical computations. The theory for fabric webs with relative motions needs to be further developed. Herein the fundamental theory for deformable webs is presented only, and numerical examples will be presented in sequel. Such a theory of deformable webs can be applied to textile or other soft materials and bio-membranes.     

On a Discrete-in-Time Order-Level Inventory Model for Deteriorating Items

An Order-Level inventory model continuous in units and discrete in time is developed for deteriorating items. The model is developed under deterministic demand and instantaneous delivery. Deterioration is assumed to be a constant fraction of the onhand inventory. An example is given to illustrate the model.     

Model and Situation Specific O.R. Methods: Risk Engineering Reliability Analysis of an L.N.G. Facility

A decision situation and model-specific O.R. method developed for reliability analysis of an Arctic liquid natural gas facility is outlined. It was developed by modifying a decision situation and model-specific O.R. method developed earlier for time (schedule or programme) risk analysis of offshore North Sea projects. The role and value of such methods is discussed in relation to general O.R. methods and specific techniques like C.P.M./PERT.     

Incorporating historical information in testing for a trend in Poisson means

An exact conditional test is developed for testing a trend in Poisson means when the historical control information is incorporated into the concurrent control data. An asymptotic conditional test is also developed as an alternative to the Tarone test. Asymptotic gains by the incorporation of the historical information is evaluated.     

An Optimization Problem with a Separable Non-Convex Objective Function and a Linear Constraint

For a class of global optimization (maximization) problems, with a separable non-concave objective function and a linear constraint a computationally efficient heuristic has been developed.The concave relaxation of a global optimization problem is introduced. An algorithm for solving this problem to optimality is presented. The optimal solution of the relaxation problem is shown to provide an upper bound for the optimal value of the objective function of the original global optimization problem. An easily checked sufficient optimality condition is formulated under which the optimal solution of concave relaxation problem is optimal for the corresponding non-concave problem. An heuristic algorithm for solving the considered global optimization problem is developed.The considered global optimization problem models a wide class of optimal distribution of a unidimensional resource over subsystems to provide maximum total output in a multicomponent systems.In the presented computational experiments the developed heuristic algorithm generated solutions, which either met optimality conditions or had objective function values with a negligible deviation from optimality (less than 1/10 of a percent over entire range of problems tested).