Solution of the facilities layout problem by simulated annealing

The simulated annealing method (SAM) is a radically new and powerful approach to solving certain integer optimization problems. The paper describes its application to the facility layout problem (QAP) and shows how it can generally match or produce superior solutions to the best known values for classical benchmark problems. The technique is also suited to microcomputer solution using interactive graphics for practical layout problems.     

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.     

Library layout via graph theory

This article reports on a case study of the design of the new Law library at the University of Canterbury in New Zealand. The objective was to produce a layout which attempts to minimize expected travel and is convenient for all users, including librarians. The problem differed from most layout studies in two ways. There are three identifiable groups of users of the library: the librarians, the students, and the law professors. Also, the intensity of travel between facilities in the library is location dependent. None of the existing layout methods that the authors tried seemed capable of producing a suitable layout. Using graph theory, the authors developed and implemented a flexible layout approach which led to a successful design. This article summarizes the steps involved, including obtaining a compromise layout which satisfied the needs of the three groups of users.     

Design of robust layout for Dynamic Plant Layout Problems

In this paper, a design for robust facility layout is proposed under the dynamic demand environment. The general strategy for a multi period layout planning problem is adaptive approach. This approach for Dynamic Plant Layout Problem (DPLP) assumes that a layout will accommodate changes from time to time with low rearrangement and production interruption costs, and that the machines can be easily relocated. On the other hand the robust layout approach, assumes that rearrangement and production interruption costs are too high and hence, tries to minimize the total material handling costs in all periods using a single layout. Robust approach suggests a single layout for multiple scenarios as well as for multiple periods. As a solution procedure for the proposed model, a Simulated Annealing (SA) algorithm is suggested, which perform well for the problems from literature and QAPLIB website. The application of suggested model for robust layout to cellular layouts has given better results compared to the robust cellular layout model of literature. For the standard DPLP of the literature, the solution values of the suggested model are very near to the results of adaptive approach. The Total Penalty Cost (TPC) is used to test the suitability of the suggested layout to be a robust layout for the given data set. TPC values indicate that the suggested layout is suitable as robust layout for the given data sets.     

Game level layout from design specification

The design of video game environments, or levels, aims to control gameplay by steering the player through a sequence of designer‐controlled steps, while simultaneously providing a visually engaging experience. Traditionally these levels are painstakingly designed by hand, often from pre‐existing building blocks, or space templates. In this paper, we propose an algorithmic approach for automatically laying out game levels from user‐specified blocks. Our method allows designers to retain control of the gameplay flow via user‐specified level connectivity graphs, while relieving them from the tedious task of manually assembling the building blocks into a valid, plausible layout. Our method produces sequences of diverse layouts for the same input connectivity, allowing for repeated replay of a given level within a visually different, new environment. We support complex graph connectivities and various building block shapes, and are able to compute complex layouts in seconds. The two key components of our algorithm are the use of configuration spaces defining feasible relative positions of building blocks within a layout and a graph‐decomposition based layout strategy that leverages graph connectivity to speed up convergence and avoid local minima. Together these two tools quickly steer the solution toward feasible layouts. We demonstrate our method on a variety of real‐life inputs, and generate appealing layouts conforming to user specifications.     

矩形布局优化问题的局部搜索蜂群算法

带平衡约束的矩形布局问题属于组合优化问题,当问题规模增大时求解困难。为提高求解效率,设计了一个蜂群算法,通过分析解的分布,提供了基于贪心策略的群体初始化方案,选择了有效的变异算子,将蜂群算法的搜索空间聚焦于最优解可能的区域。另外设计了一个二次局部搜索算法,对解的质量进行进一步提升。在10个公开的案例上与目前性能最好的算法进行了对照,提出的蜂群算法在其中9个较大规模的案例上超过了现有算法。理论分析和实验结果表明,相对于现有算法,所提蜂群算法能明显提高求解效率。     

Solving dynamic double row layout problem via combining simulated annealing and mathematical programming

Double row layout problem (DRLP) is to allocate facilities on two rows separated by a straight aisle. Aiming at the dynamic environment of product processing in practice, we propose a dynamic double-row layout problem (DDRLP) where material flows change over time in different processing periods. A mixed-integer programming model is established for this problem. A methodology combining an improved simulated annealing (ISA) with mathematical programming (MP) is proposed to resolve it. Firstly, a mixed coding scheme is designed to represent both of sequence of facilities and their exact locations. Secondly, an improved simulated annealing algorithm is suggested to produce a solution to DDRLP. Finally, MP is used to improve this solution by determining the optimal exact location for each facility. Experiments show that this methodology is able to obtain the optimal solutions for small size problems and outperforms an exact approach (CPLEX) for problems of realistic size.     

Consumption universes based supermarket layout through association rule mining and multidimensional scaling

The success of retail business is influenced by its fast response and its ability in understanding consumers’ behaviors. Analysis of transaction data is the key for taking advantage of these new opportunities, which enables supermarkets to understand and predict customer behavior, has become a crucial technique for effective decision-making and strategy formation. We propose a methodological framework for the use of the knowledge discovery process and its visualization to improve store layout. This study examines the layout strategy in relation to supermarket retail stores and assists managers in developing better layout for supermarkets. We use the buying association measure to create a category correlation matrix and we apply the multidimensional scale technique to display the set of products in the store space. This is a new approach to supermarket layout from industrial categories to consumption universes that is consumer-oriented store layout approach through a data mining approach. This framework is useful for both academia and retail industry. For industry professionals, it may be used to guide development of successful layout. Retailers can utilize the proposed model to dynamically improve their in-store conversion rate. As the empirical study, a practical application proceeded for Migros Turk, a leading Turkish retailing company.     

Growing optimal pin-jointed frames

The problem is addressed of growing least-volume trusses, starting from the simplest possible layout rather than from a complex ground structure. This approach to the optimal-layout problem is shown to be well suited to deflection-space methods of solution, which allow geometry and layout to be optimized simultaneously. The method has the advantage that it can produce much simpler, more realistic structures; allows joint-weight to be taken into account; and involves smaller computational problems. The key task at each stage is to generate least-volume linearly-elastic pin-jointed frames with prespecified numbers of joints. This problem is well-posed and is shown by examples to be solvable. The obstacles to be overcome in order to produce a practical computer implementation are analysed.     

Facilities layout—A survey of solution procedures

The main characteristics of the most-used solution procedures for the facility layout problem are summarized. The characteristics include input required, limitations, type of output obtained, and some other general characteristics. Quantitative and computer-based models will sometimes produce odd layout shapes. For this reason, optimization models and computer prorams designed to plan facility layouts, based on optimizing certain objectives, can be useful only for determining some guidelines for the planners. While these models can be used for planning alternative layouts, considerations of qualitative and personnel factors should be given during the layout finalization phase.     

A multi-objective approach to facility layout problem by genetic search algorithm and Electre method

Classical approaches to layout design problem tend to maximise the efficiency of layout, measured by the handling cost related to the interdepartmental flow and to the distance among the departments. However, the actual problem involves several conflicting objectives hence requiring a multi-objective formulation. Multi-objective approaches, recently proposed, in most cases lead to the maximisation of a weighted sum of score functions. The poor practicability of such an approach is due to the difficulty of normalising these functions and of quantifying the weights. In this paper, this difficulty is overcome by approaching the problem in two subsequent steps: in the first step, the Pareto-optimal solutions are determined by employing a multi-objective constrained genetic algorithm and the subsequent selection of the optimal solution is carried out by means of the multi-criteria decision-making procedure Electre. This procedure allows the decision maker to express his preferences on the basis of the knowledge of candidate solution set. Quantitative (handling cost) and qualitative (adjacency and distance requests between departments) objectives are considered referring to a bay structure-based layout model, that allows to take into account also practical constraints such as the aspect ratio of departments. Results obtained confirm the effectiveness of the proposed procedure as a practicable support tool for layout designers.     

微粒群算法在产品组件布局设计中的应用

提出了一种基于微粒群算法的自适应优化布局求解算法,该算法以组件特征模型为基础,在微粒群算法中引入人机交互技术,从整体上自动优化布局方案,以满足约束条件为目标。并以手机组件的布局求解为例,对该算法进行了验证。理论和实例分析表明,该算法能有效地生成多个手机组件布局方案。     

基于遗传算法的大规模矩形件优化排样

大规模矩形件优化排样是一个典型的组合优化问题，属于NP-hard问题．实际工程中对一个排样方案一般有满足“一刀切”的工艺要求，“一刀切”要求增加了对排样的约束．提出的优化算法，将矩形匹配分割算法作为遗传算法染色体的解码器实现一个排样方案，用遗传算法进行排样方案的全局搜索．算例比较表明，该算法可以求得满足“一刀切”约束的最优解．     

Modeling the machine layout problem

In this paper, a mathematical model for the machine layout problem is presented. The objective function of the model minimizes the total cost involved in transporting material between each pair of machines. The constraints ensure that: (i) the pickup and drop-off points of a machine fall within the boundaries of the machine; (ii) no two machines in the layout overlap; and (iii) the machines are located inside the building. A simulated annealing algorithm for solving the model is also presented. The solution provided by the algorithm indicates the MHS paths, the relative positioning of each machine, the pick-up and drop-off points for each machine, and clearance between machines.     

A dynamic multi-objective approach for the reconfigurable multi-facility layout problem

The multi-facility layout problem involves the physical organization of departments inside several facilities, to allow flexible and efficient operations. This work studies the facility layout problem in a new perspective, considering a group of facilities, and two different concerns: the location of departments within a group of facilities, and the location of departments inside each facility itself. The problem is formulated as a Quadratic Programming Problem with multiple objectives and unequal areas, allowing layout reconfigurations in each planning period. The objectives of the model are: the minimization of costs (material handling inside facilities and between facilities, and re-layout); the maximization of adjacency between departments; and the minimization of the “unsuitability” of department positions and locations. This unsuitability measure is a new objective proposed in this work, to combine the characteristics of existing locations with the requirements of departments. The model was tested with data from the literature as well as with a problem inspired in a first tier supplier in the automotive industry. Preliminary results show that this work can be viewed as an innovative and promising integrated approach for tackling real, complex facility layout problems.     

A hybrid hierarchical agent-based simulation approach for buildings indoor layout evaluation based on the post-earthquake evacuation

In the aftermath of severe earthquakes, building occupants evacuation behaviour is a vital indicator of the performance of an indoor building design. However, earthquake evacuation has been systematically neglected in the current building design practice. Arguably, one of the primary reasons for this is that post-earthquake evacuation behaviour is complex and distinct from all other types of evacuation behaviours such as fire. Thus, a comprehensive approach to considering the integration of human evacuation behaviour and a building's indoor layout design, mainly focused on non-structural damage, has been consistently neglected in the literature. In this paper, a hierarchical hybrid Agent-Based Model (ABM) framework integrated with a Cellular Automata (CA) and a 2D Building Information Model (BIM) damage visualisation to consider an approximation of non-structural damage has been developed. The proposed ABM incorporates learning mechanisms and human psychological aspects influencing evacuees' utility during the navigation process. The proposed approach was verified by comparing the results to previous real-life post-earthquake evacuation data and a “model to model” comparison of results from the existing relevant studies. The model prototype was successfully tested to simulate the pedestrian evacuation process from one floor of the new engineering building at The University of Auckland, New Zealand. The proposed simulation approach has been carried out for two different internal layout design alternatives where five population sizes are evacuated through different scenarios. The outputs from this study can be used to improve the design's compatibility of the building's indoor layout with the occupants' post-earthquake evacuation behaviour.     

A CAD-based layout planning procedure

A CAD software based solution procedure is proposed for the layout planning problem that also incorporates the optimization of conflicting, multiple criteria. A prototype software implementing this proposed approach has been developed and it uses AUTOCAD as the graphics environment.     

Computer assisted plant layout using a graphics editor

Computer assisted plant layout has been available to industrial engineers, in one form or another, for a number of years. In this paper a semi-interactive computer graphics approach to layout planning is described. A graphics editor, CMASK, developed for designing integrated circuits was utilized to create plant-facility layout. The method based on a “layer by layer” approach to creating a layout is flexible and gives the layout designer a complete control to the layout generation process.     

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.