装填布局的同构和非同构模式

装填布局问题在工程实践上具有广泛的应用，在理论上属于NPC问题．布局模式是其中的一个重要问题．该文以卫星舱布局方案设计为背景，研究装填布局模式问题，定义了同构和非同构布局模式、待布物的布局等价关系等概念，给出了关系矩阵和模式矩阵以及它们的变换，描述了布局模式控制区和非同构度，提出了同构和非同构布局模式的识别及构造方法．文后讨论了布局模式的若干应用．该工作希望能为缓解装填布局优化问题求解时存在的组合爆炸以及构造高效的求解算法提供启发和借鉴．     

基于几何推理的布局设计新方法

面向约束的布局设计问题一直是布局研究的热点．本文提出了一个基于几何推理的布局设计生成算法，其最大优点就是充分利用参数化设计的优点，建立了影响布局设计的变量之间的关系．该算法具有较强的柔性，易于扩充，并支持约束一致性检测和影响布局设计参变量的局部修改．算法已在作者研制的车身内布置设计系统中得到了较好的应用．     

一个有效的圆片规模布局算法

本文提出了一个圆片规模布局算法，它是国外一个相应算法的改进形式，区别在于利用力定向布局法的方式不同。在相对位置阶段，该算法利用布局的层次特性将需确定所有电路元件相对位置的问题缩减至仅需确定宏电路元件相对位置的问题；在实际位置阶段，采用分治策略和取消前阶段层次划分的方式回避了需确定任意元实际位置的问题．其时间复杂度远低于国外相应算法．     

旋转锥体空间中圆柱体群的布局优化

旋转圆锥体空间中不等圆柱体群的布局为人造卫星再入舱布局的简化模型，属带动力性能约束的Packing优化问题，具有NP难度．本文提出了模式迭换法，用以构造布局拓扑模式，形成初始布局方案；推荐了在此初始布局方案下进行布局寻优的算法；给出了缓解“组合爆炸”的技巧和算例验证．此类问题具有广阔的工程应用前景．     

基于粒子群优化算法的约束布局优化

布局优化是NP难问题，也是复杂的非线性约束优化问题．针对这个问题，将新的基于粒子群优化的方法应用于布局参数的优化，提出了适合粒子群优化的约束处理，并通过与直接搜索算法的混合，加强了算法在局部区域的搜索能力．通过实例将该算法与乘子法以及基于遗传算法的布局优化方法进行了比较．仿真结果表明，该算法可以提高布局优化问题解的质量，同时降低计算费用．     

一种基于八叉树结构表达的三维实体布局启发式算法

本文在利用八叉树结构表达三维实体布局块及布局空间的基础上,根据八叉树同构节点匹配的思想设计了一个三维实体布局的启发式算法,并提出了三环图方法,解决了八叉树节点的同构识别问题．理论分析及计算的结果表明了该算法对于具有任意形状和大小的布局对象的三维布局问题来说效果理想．     

基于遗传算法的布局问题求解

布局问题是VLSI布图设计中的重要问题，传统的方法很难得到满意的解答。针对该问题，文中提出了一个基于遗传算法的求解方法，并将它应用到VLSI门阵列模式布局设计中，构造了一个较完备的综合布局目标函数，引入并定义了通道拥挤度。实验结果表明，所提出的方法能在较短的时间内提供优化解，为VLSI布局设计提供了一种新的思路。     

基于单亲遗传算法的动态设备布局仿真研究

针对柔性生产环境下的设备布局问题，提出了一种基于单亲遗传算法原理的启发式算法．发展了一种新颖的适用于动态设备布局的遗传换位操作算子，并提出在单期布局编码子串上应用换位概率的策略，增加了种群的多样性．Matlab编程实现算法，通过大量仿真模拟并与其他算法进行比较分析，证实了所提出方法的有效性．提出的算法在问题规模不大时可以迅速而准确的获得优化解，在问题规模较大时也能在较短时间（与其他算法相比）获得满意解，因此具有较好的综合性能．     

空间布局中估价函数的一种构造方法

研究如何利用有关问题域的启发信息以降低计算费用是人工智能求解的基本问题之一，本文以计算机结构布局设计为背景，提出了构造布局设计中估价函数的ＡＨＰ方法．通过计算估价函数值，采用最佳优先搜索策略，可避免组合爆炸，保证在有限的时空界限内找到满意解．本文所提出的方法不仅适用于空间布局设计，而且容易推广到一般设计问题，具有重要的应用价值．     

基于聚类分解的WCDMA基站布局规划算法

针对大规模WCDMA无线网络基站布局规划问题，提出一种基于聚类分解的分层算法．在聚类分解中，以测试点信号增益矩阵构造聚类分解数据，并给出了收敛判定函数和相似度计算方法．在分层算法中，首先用K均值聚类将原问题分解为K个子规划问题，然后对各子问题求解整数规划问题，最后对各子问题的基站布局结果进行全局调整．仿真计算验证了该算法的有效性．     

Integrated design of workcells and unidirectional flowpath layout

In manufacturing cells layout design with a unidirectional flow system, the accurate distance between two workcells can be uncovered with both the determination of IO port locations after the layout design of the cell with its orientation and the unidirectional flowpath layout design. This paper presents the method to obtain a global solution for manufacturing workcells and unidirectional flowpath layout design (ICFLD) with consideration of IO ports of workcells. The flow distance between two workcells is calculated from output port of one workcell to input port of the other workcell through the unidirectional flowpath layout. A zero-one integer programming model is developed for the ICFLD problem. And a heuristic algorithm for the ICFLD problem is developed by decomposing the ICFLD problem into two subproblems and iteratively and alternately solving the decomposed subproblems. Computational experiments are performed and its results are analyzed.     

Loop layout design problem in flexible manufacturing systems using genetic algorithms

A common layout for flexible manufacturing systems is a loop network with machines arranged in a cycle and materials transported in only one direction around the cycle. Traffic congestion is usually used as the measure for evaluating a loop layout, which is defined as the number of times a part traverses the loop before its processing is completed. This paper investigates the problem of designing a loop layout system with genetic algorithms. The essence of the problem is how to determine the order of machines around the loop subject to a set of part-route constraints so as to optimize some measures. A hybrid approach of genetic algorithms and neighborhood search is developed for solving the problem. The proposed method is tested on hypothetical problems. Computational results demonstrate that genetic algorithms can be a promising approach for loop layout design in flexible manufacturing systems. Two typical measures, the minsum and minmax congestion measures, are examined and computational experiments show that the minsum approach outperforms the minmax approach.     

Unidirectional loop network layout by a LP heuristic and design of telecommunications networks

In this paper, we present a new linear programming-based heuristic procedure for optimal design of the unidirectional loop network layout problem. The heuristic procedure employs a linear programming formulation and solves the problem using the flow matrix of the unidirectional loop problem. To find an optimal solution, one can either generate all possible solutions or use a branch-and-bound procedure. But, both above methods require very high computational time and computer memory for larger problems. The heuristic developed in this paper is quite fast and obtains near optimal solutions. The heuristic procedure was tested on 16 different problems selected from the literature. The results showed that in most cases optimal—and in a few cases near optimal—solutions were obtained with very little computational time. Several examples are discussed. We also demonstrate that the above problem formulation and approach can be used to solve a special class of telecommunication networks where a set of computers (or processors) are attached by unidirectional point-to-point links around a loop.     

Multiple-attribute decision making methods for plant layout design problem

The layout design problem is a strategic issue and has a significant impact on the efficiency of a manufacturing system. Much of the existing layout design literature that uses a surrogate function for flow distance or for simplified objectives may be entrapped into local optimum; and subsequently lead to a poor layout design due to the multiple-attribute decision making (MADM) nature of a layout design decision. The present study explores the use of MADM approaches in solving a layout design problem. The proposed methodology is illustrated through a practical application from an IC packaging company. Two methods are proposed in solving the case study problem: Technique for order preference by similarity to ideal solution (TOPSIS) and fuzzy TOPSIS. Empirical results showed that the proposed methods are viable approaches in solving a layout design problem. TOPSIS is a viable approach for the case study problem and is suitable for precise value performance ratings. When the performance ratings are vague and imprecise, the fuzzy TOPSIS is a preferred solution method.     

Genetic algorithms for designing loop layout manufacturing systems

A common layout for flexible manufacturing system is loop network with machines arranged in a cycle and materials transported in only one direction around the cycle. Congestion is a common measure for evaluating a loop layout. This paper investigates the problem of designing loop layout system with both of minsum and minmax congestion measures. A hybrid heuristic of genetic algorithms and neighborhood search is developed for solving such problem and preliminary computational results are reported.     

Bidirectional differential on-chip wave-pipelined serial interconnect with surfing

In the literature, surfing technique has been proposed for differential on-chip wave-pipelined serial interconnects with uniform repeaters (UR) and non-uniform repeaters to increase the data transfer rate for unidirectional schemes. In this paper, a novel bidirectional data transfer through the differential wave-pipelined serial interconnects with surfing for UR is proposed. A new circuit called ‘Bidirectional surfing inverter pair’ is proposed for differential wave-pipelined serial interconnects. The method of logical effort is used for the design of surfing circuits. To evaluate the efficiency of these techniques, 40 mm metal 4 interconnects using the proposed surfing techniques are implemented along with transmitter, receiver and delay locked loop in UMC 180 nm technology and their performances are studied through post layout simulations. The proposed bidirectional differential surfing scheme has a maximum data transfer rate of 2 Gb/s and has allowable jitter of 52 ps on both directions through the same interconnects.     

Multiobjective layout optimization of robotic cellular manufacturing systems

This paper proposes a multiobjective layout optimization method for the conceptual design of robot cellular manufacturing systems. Robot cellular manufacturing systems utilize one or more flexible robots which can carry out a large number of operations, and can conduct flexible assemble processes. The layout design stage of such manufacturing systems is especially important since fundamental performances of the manufacturing system under consideration are determined at this stage. In this paper, the design criteria for robot cellular manufacturing system layout designs are clarified, and objective functions are formulated. Next, layout design candidates are represented using a sequence-pair scheme to avoid interference between assembly system components, and the use of dummy components is proposed to represent layout areas where components are sparse. A multiobjective genetic algorithm is then used to obtain Pareto optimal solutions for the layout optimization problems. Finally, several numerical examples are provided to illustrate the effectiveness and usefulness of the proposed method.     

Applying simulated annealing for designing cellular manufacturing systems using MDmTSP

The design of cellular manufacturing systems involves many structural and operational issues. One of the important design steps is the formation of part families and machine cells (cell formation). Despite a large number of papers on cell formation published worldwide, only a handful incorporates operation sequence in layout design (intra-cell move calculations). We propose a solution to solve the part-family and machine-cell formation problem considering the within-cell layout problem, simultaneously. In this paper, the cellular manufacturing system is formulated as a multiple departures single destination multiple travelling salesman problem (MDmTSP) and a solution methodology based on simulated annealing is proposed to solve the formulated model. Numerical examples show that the proposed method is efficient and effective in finding optimal solutions. The results also indicate that the proposed approach performs well compared to some well-known cell formation methods.     

A revised electromagnetism-like mechanism for layout design of reconfigurable manufacturing system

The layout design problem is one of the most important issues for manufacturing system design and control. A revised electromagnetism-like mechanism (REM) is proposed in this paper for the layout design of reconfigurable manufacturing systems utilizing automated guided vehicle. First, the formal model considering both loaded and empty flows is given. Then the REM is developed to solve the proposed model. In the REM, particles are encoded discretely. The charge of a particle is calculated according the total material handling cost of the particle. In the local search procedure, variable neighbourhood search strategy based on Hamming distance is adopted. In the moving procedure, the particles are moved according to the ordering of each element. To verify the effect of the proposed method, several computation cases are carried out. The computation results show that the proposed method is able to get optimal solutions for small scale problems and near optimal solutions within limited computation time for large scale problems. This indicates that the proposed method is effective and efficient.     

A -based layout design for gratings allocation

In the design process of gratings, the grating layout design is the most important activity influencing manufacturing cost. In the grating layout design, the key to saving manufacturing cost is to find a design with a minimal number of cutting operations. This paper presents an application of the A^* algorithm in grating layout design. The design problem is represented as the space search problem of design alternatives. A^* explores the feasible alternatives within the space, until an optimal solution is obtained.