Constructing an optimal facility layout to maximize adjacency as a function of common boundary length

An effective facility layout implies that departments with high flow are laid adjacent. However, in the case of a very narrow boundary length between the neighbouring departments, the adjacency would actually be useless. In traditional layout design methods, a score is generally assigned independent of the department’s boundary length. This may result in a layout design with a restricted material flow. This article proposes a new concept of adjacency in which the department pairs are laid adjacent with a wider path. To apply this concept, a shop with unequal rectangular departments is contemplated and a mathematical programming model with the objective of maximizing the sum of the adjacency degrees is proposed. A computational experiment is conducted to demonstrate the efficiency of the layout design. It is demonstrated that the new concept provides a more efficient and a more realistic layout design.     

汽车座椅骨架构件布局设计方法

传统的汽车座椅骨架构件布局依靠经验设计,不仅设计效率低,而且得不到性价比最优的结构.以某轿车后排座椅板管结构骨架为研究对象,基于结构拓扑优化设计技术,提出了座椅骨架构件布局设计方法.首先,根据骨架外观形状及尺寸要求,确定设计区域,并根据实际的安全带加载工况,建立设计模型;然后,以结构静刚度最大为优化目标,采用变密度法对结构进行拓扑优化设计,并根据拓扑优化结果,提出2种不同的布局方案;最后,根据有限元分析结果确定最终的设计方案,并对优化设计结果进行行李箱后撞的安全性分析.研究结果表明,在骨架质量下降1.92%的情况下,整体静态刚度提高19.0%,并满足动态碰撞的安全性要求.采用所提出的设计方法,可以得到最优座椅骨架构件布局结构.     

TRANSFORMATION FROM CONCEPTUAL TO EMBODIMENT DESIGN

In the paper, a graph-theoretic approach for transformation from conceptual design to embodiment design is developed. An adjacency matrix corresponding to a digraph representing the flow of energy in the designed object provides an input to the algorithm. The algorithm generates clusters that are useful in design of a physical layout of the designed object. The concepts introduced in the paper are illustrated with examples.     

A Method for the Configuration Design of a Space Truss Deployable Mechanism and Its Application

A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency matrixes at different work-stage of the mechanism,which is helpful to completely understand the composition and change rules of the metamorphic mechanism,are analyzed to indicate the metamorphic relationship in one working cycle. Furthermore,the static distance matrix,dynamic distance matrix and stiffness matrix of the mechanism are derived to assess the ability of the designed configuration to reveal some of the topological characteristics like compactness,dynamic sensitivity and stiffness. Using this proposed method in a space truss deployable mechanism helps the designer to evaluate its performance at the conceptual stage of design and make a rapid,reasonable selection for configuration design,which provides means for processing its type of analysis by computer.     

Graph theoretic algorithm for automatic operation sequencing for progressive die design

The paper presents a formal graph representation scheme for stamping operation sequencing for sheetmetal progressive dies and a graph theoretic method for automatic determination of the stamping operation sequence. Operation relations are represented by two graphs: an operation precedence graph and an adjacency graph. The first represents precedence constraints defined by best manufacturing practices. The second represents geometric infeasibility relations between operations. Each operation is a member of both graphs. The graphs are automatically generated from a set of stamping operations, which in turn are associated with stamping features of a part. The operation precedence graph is then verified to be acyclic using a coloured Depth First Search. Based on the operation precedence graph, a modified topological sort algorithm is applied to cluster the operations into partially ordered sets. Finally, a graph-colouring algorithm is applied to the operation adjacency graph on the partially ordered operation sets. The algorithm is implemented in C++ and is fully integrated with SolidWorks computer-aided design system. A case study is presented to illustrate the algorithm.     

A new approach to the block layout problem

The main problem concerned with applying graph theory to facilities layout is the conversion of the dual graph to a block layout. This paper presents a new method of producing a planar orthogonal layout or floorplan of a set of facilities subject to adjacency and area constraints. It improves upon previous approaches by accepting any maximal planar graph representing the adjacencies as input. Simple selection criteria for choosing the next facility to be inserted into the floorplan are used. Further, any sensible orthogonal shape for the facilities in the resulting floorplan can be generated.     

Evaluation of an application of graph theory to the layout problem

When designing a facility layout it is desirable to obtain an optimum design which satisfies certain necessary relationships among departments. Recent research has indicated that applying graph theory to the layout problem can result in the development of improved solutions, but little can be found to indicate how much better the resultant solutions are. The objectives of this paper are to develop a graph theory approach based on research experience and suggestions of Moore, Carrie and Seppanen, to develop a general computer program implementing the procedure and to compare its performance with that of CRAFT, CORELAP and ALDEP. The comparisons are based upon the adjacency relationships satisfied in the resultant layouts. The procedure finds the graph G equivalent to the problem being solved and then generates one of its maximal spanning trees, which after being transformed to its ‘string’ equivalent, is used to extract a maximal planar sub-graph of G. The dual of this sub-graph represents the desired solution. This approach allowed two usual problems to be avoided; firstly, testing for planarity of a graph and secondly, testing for cycles in the generation of a maximal spanning tree. The resultant PL/1 program, called graph and string-oriented layout (GASOL), is used to solve a standard set of eight problems, i.e. Nugent's problem set. The generated layouts were then compared to those obtained by CRAFT, CORELAP, and ALDEP on the same set of problems. The results of these comparisons showed that GASOL satisfies more of the number of layout adjacencies and achieves higher ‘scored’ layout arrangements than either CRAFT, CORELAP, or ALDEP, As a consequence more flow or material handling volume is included in a GASOL layout. The increase in the number of adjacencies ranges from a low of 53% to a high of 63.1%. This computational experience suggests that a graph theory approach to the layout problem can provide significantly improved results over those obtained by these existing computerized layout routines, with moderately increased computational times.     

A genetic algorithm based heuristic for adjacent paper-reel layout problem

In this paper, we present an algorithm that solves a paper reel layout problem where the available space is divided into equal-size cells. The problem is to find a layout with the minimum transportation cost subject to adjacency and other constraints. A genetic algorithm is used in a two-stage iterative approach to solve the problem. Computational results seem to indicate the efficiency and effectiveness of the proposed solution method.     

Eigensolution of augmented graph products using shifted inverse iteration method

Two important matrices associated with graphs are adjacency and Laplacian matrices. In this paper efficient methods are presented for eigensolution of graph products augmented by other graphs. For augmentations that do not destroy the symmetry of the graph products, a method is proposed for decomposition of matrices resulting in considerable simplification of their eigensolution. For graphs composed of two non‐overlapping graph products joined through a small number of link members, a method based on shifted inverse iteration is proposed which utilizes all eigenvalues and eigenvectors of each individual graph products. Owing to the availability of fast methods for eigensolution of graph products, this method simplifies the eigensolution of a variety of graph models and proves to be very efficient in determining the few smallest eigenpairs of these models with high levels of accuracy. Copyright © 2010 John Wiley & Sons, Ltd.     

A multi-improved genetic algorithm for facility layout optimisation based on slicing tree

For the facility layout optimisation problem, we use the slicing tree structure based on the order of traversal to form a new chromosome encoding system demonstrating facilities’ order, the relationship and the location. We generate the initial solution based on two principles namely the facilities’ adjacency and random generation. The structure of chromosome is made up with three sections in the research so that we can do the genetic operations to these three sections respectively, and we use dynamic and feedback mechanisms to improve the penalty function. As a result, the analysis of typical cases shows that there are certain improvements to this algorithm both in effectiveness and efficiency.     

多单元制造系统布局设计

从布局设计的角度,提出多单元制造系统的概念,把各种制造系统的布局问题转化为多单元制造系统布局设计问题,包括设备布局和制造单元布局两个方面。对于设备布局问题,给出一种优化建模与虚拟现实技术相结合的求解策略;对于单元布局问题,给出一种集成的布局设计方法。     

基于力导向算法的线束连接图自动布局研究

线束连接图是线束图纸中去除接插件、由线段组成的表示接插件连接关系的连通无环图,线束连接图决定了线束图纸布局的骨架,是线束图纸布局的主要内容。该文将无向图布局理论中的力导向不算模型和算法引入到汽车线束连接图的布局中,实现了连接图主干的自动搜索和线束分支的约束对称布局,进而完成了汽车线束连接图的自动布局,为汽车线束图纸的自动布局提供了有效方法和技术。     

基于专利地图的企业专利布局设计研究

合理的专利布局设计能够使企业全面掌握行业内的技术实力,准确识别竞争对手,抢占技术制高点.专利地图可以将相关专利信息系统化、直观化、图形化,为了解行业动向、指引研发方向,从而进行专利布局提供依据.从专利布局角度出发并结合专利地图知识,将企业专利布局设计流程简化为4种模型,即专利数据采集模型、企业发展状态模型、竞争对手定位模型和技术潜力发展模型,通过对每一种模型的制作和分析,使企业明确自身的发展状态、竞争者的威胁以及行业技术发展潜力,从而有效地进行专利布局设计,提高竞争力.最后以金刚石工具行业中的某企业为例进行验证.     

基于Floyd算法的扇形中深孔爆破布孔优化设计

地下矿中深孔爆破炮孔布置设计直接影响爆破效果和生产成本,前期研究提出的基于单源最短路径的优化算法极大提升了布孔优化设计的效率,但不能完全满足生产实际的应用.分析了炮孔布置与中深孔爆破参数的关联性,将炮孔孔底距作为主要控制调节参数,应用多源点最短路径的动态规划思想,基于Floyd算法建立中深孔爆破扇形炮孔排面优化设计算法...     

产品操作界面元素布局多目标优化设计

目的针对产品设计中操作界面布局设计时存在的随意性、不确定性大等问题,使用多目标优化设计的方法,寻找界面元素的最优布置,以提升界面的使用舒适性和人机交互效率。方法在分析了工效学准则和界面布局美度评价准则的基础上,确立了层次性、相关性、简洁性和舒适性四个界面布局基本原则,并依据原则构建了界面元素布局多目标优化数学模型,在此模型的基础上采用改进的遗传算法,建立基于遗传算法的界面元素布局多目标优化方法。结果给出产品操作界面布局设计的基本原则,提出一种基于遗传算法的产品操作界面元素布局的多目标优化方法及流程。结论提出的布局原则和优化方法能较好地协助设计师获得满足设计需求的布局方案,实例结果表明了理论模型的合理性与遗传算法对于界面元素布局多目标优化问题求解的有效性。     

An optimal approach for maximizing the number of adjacencies in multi floor layout problem

Multi-floor facility layout problem concerns the arrangement of departments on the different floors. In this paper, a new mathematical model is proposed for multi-floor layout with unequal department area. Maximising the number of useful adjacencies among departments is considered as the objective function. The adjacencies are divided into two major categories: horizontal and vertical adjacencies. The horizontal adjacency may be occurred between the departments assigned to same floors while the vertical can be happened between departments assigned to any consecutive floors. A minimum common boundary length (surface area) between any two horizontal (vertical) adjacent departments is specified. The efficiency of the model is demonstrated by six illustrative examples. The proposed model is practical in multi-floor plant where the existence of adjacencies between departments is useful or essential due to possible establishment of conveyor, transferring pipes, lift truck route, etc.     

An efficient method for decomposition of regular structures using graph products

In this paper an efficient method is presented for calculating the eigenvalues of regular structural models. A structural model is called regular if they can be viewed as the direct or strong Cartesian product of some simple graphs known as their generators. The eigenvalues of the adjacency and Laplacian matrices for a regular graph model are easily obtained by the evaluation of eigenvalues of its generators. The second eigenvalue of the Laplacian of a graph is also obtained using a much faster and much simple approach than the existing methods. Copyright © 2004 John Wiley & Sons, Ltd.     

基于VRML模型的协同装配工艺规划仿真方法

在研究了虚拟现实建模语言(VRML)模型特点以及协同装配工艺规划过程的基础上,将以VRML三维模型为设计信息载体的协同装配工艺规划仿真分为无约束的规划仿真和基于约束的规划仿真,并提出了相应的实现方法.所提方法使网络化的同步协同装配规划操作成为可能,通过实时交流,使产品装配工艺规划能够在集合多方设计经验的基础上方便快捷地实现.应用实例的应用结果表明,所提方法可快速发现设计缺陷并显著地缩短产品工艺规划周期.     

扁平化风格插画在趣味玩具包装中的应用

目的 以虚拟品牌——ciiica（起卡玩具）为实验材料展开系列创作,从全新的角度探讨趣味玩具包装设计,解决玩具包装中存在的问题,拓展扁平化设计风格的应用。方法 在该品牌包装设计过程中,通过对扁平化风格特征进行分析,从包装设计的图形、色彩、文字和版式等要素出发进行设计。运用插画具有的独特艺术和文化内涵,实现扁平化包装设计的简约优雅、图形语义明确、版面秩序化、颜色纯粹化的特征。结论 反映品牌设计的创作理念和风格样式,为包装设计带来更加丰富、生动和多样化的表现形式,使品牌包装视觉语言表达的效果达到最大化。     

On the worst case performance of TESSA

TESSA is a facility layout heuristic for obtaining a maximal planar adjacency graph (MPG) from relationship chart data. Computational experiments performed by Boswell (1992b) have shown that the algorithm produces good quality solutions, almost all of which are above 90% of the often unattainable upper bound. In this paper we show that the heuristic displays arbitrarily bad theoretical worst case performance.