Integrated optimal method for cell formation and layout problems based on hybrid SA algorithm with fuzzy simulation

To adapt to the complex and changeable market environment,the cell formation problems(CFPs) and the cell layout problems(CLPs) with fuzzy demands were optimized simultaneously. Firstly,CFPs and CLPs were described formally. To deal with the uncertainty fuzzy parameters brought,a chance constraint was introduced. A mathematical model was established with an objective function of minimizing intra-cell and inter-cell material handling cost. As the chance constraint of this problem could not be converted into its crisp equivalent,a hybrid simulated annealing(HSA) based on fuzzy simulation was put forward. Finally,simulation experiments were conducted under different confidence levels. Results indicated that the proposed hybrid algorithm was feasible and effective.

Layout problem of multi-component systems arising for improving maintainability

To improve the mainlainability design efficiency and quality, a layout optimization method for maintainability of multi-component systems was proposed. The impact of the component layout design on system maintainability was analyzed, and the layout problem for maintainability was presented. It was formulated as an optimization problem, where maintainability, layout space and distance requirement were formulated as objective functions. A multi-objective particle swarm optimization algorithm, in which the constrained-domination relationship and the update strategy of the global best were simply modified, was then used to obtain Pareto optimal solutions for the maintainability layout design problem. Finally, application in oxygen generation system of a spacecraft was studied in detail to illustrate the effectiveness and usefulness of the proposed method. The results show that the concurrent maintainability design can be carried out during the layout design process by solving the layout optimization problem for maintainability.

Ant Colony System for a Fuzzy Adjacent Multiple-Level Warehouse Layout Problem

A warehouse layout problem where the warehouse has more than one level and both the distance from the cell to the receive/exit bay and demand of item types are fuzzy variables is proposed. The problem is to find a layout with the minimum transportation cost subject to adjacency and other constraints. A fuzzy expected value model is given and an ant colony system is designed to solve the problem. Computational results indicate the efficiency and effectiveness of the method.

An Algorithm for Solving Generalized Single Row Facility Layout Problem

Layout design problem is to determine a suitable arrangement for the departments so that the total costs associated with the flow among departments become least. Single Row Facility Layout Problem, SRFLP, is one of the layout problems that have many practical applications. This problem and its specific scenarios are often used to model many of the raised issues in the field of facility location. SRFLP is an arrangement of n departments with a specified length in a straight line so that the sum of the weighted distances between the pairs of departments is minimized. This problem is NP-hard. In this paper, first, a lower bound for a special case of SRFLP is presented. Then, a general case of SRFLP is presented in which some new and real assumptions are added to generate more practical model. Then a lower bound, as well as an algorithm, is proposed for solving the model. Experimental results on some instances in literature show the efficiency of our algorithm.

An Adaptive Strategy-incorporated Integer Genetic Algorithm for Wind Farm Layout Optimization

Energy issues have always been one of the most significant concerns for scientists worldwide.With the ongoing over exploitation and continued outbreaks of wars,traditional energy sources face the threat of depletion.Wind energy is a readily available and sustainable energy source.Wind farm layout optimization problem,through scientifically arranging wind turbines,significantly enhances the efficiency of harnessing wind energy.Meta-heuristic algorithms have been widely employed in wind farm layout optimization.This paper introduces an Adaptive strategy-incorporated Integer Genetic Algorithm,referred to as AIGA,for optimizing wind farm layout problems.The adaptive strategy dynamically adjusts the placement of wind turbines,leading to a substantial improvement in energy utilization efficiency within the wind farm.In this study,AIGA is tested in four different wind conditions,alongside four other classical algorithms,to assess their energy conversion efficiency within the wind farm.Experimental results demonstrate a notable advantage of AIGA.

An extended discrete particle swarm optimization algorithm for the dynamic facility layout problem

We extended an improved version of the discrete particle swarm optimization (DPSO) algorithm proposed by Liao et al.(2007) to solve the dynamic facility layout problem (DFLP). A computational study was performed with the existing heuristic algorithms, including the dynamic programming (DP), genetic algorithm (GA), simulated annealing (SA), hybrid ant system (HAS), hybrid simulated annealing (SA-EG), hybrid genetic algorithms (NLGA and CONGA). The proposed DPSO algorithm, SA, HAS, GA, DP, SA-EG, NLGA, and CONGA obtained the best solutions for 33, 24, 20, 10, 12, 20, 5, and 2 of the 48 problems from (Balakrishnan and Cheng, 2000), respectively. These results show that the DPSO is very effective in dealing with the DFLP. The extended DPSO also has very good computational efficiency when the problem size increases.

The Model for Two-dimensional Layout Optimization Problem with Performance Constraints and Its Optimality Function

This paper studies the two-dimensional layout optimization problem. An optimization model with performance constraints is presented. The layout problem is partitioned into finite subproblems in terms of graph theory, in such a way of that each subproblem overcomes its on-off nature optimal variable. A minimax problem is constructed that is locally equivalent to each subproblem. By using this minimax problem, we present the optimality function for every subproblem and prove that the first order necessary optimality condition is satisfied at a point if and only if this point is a zero of optimality function.

A Mixed-Integer Programming Formulation for a Simplified Model of the Double Row Layout Problem

The double row layout problem(DRLP)is to assign facilities on two rows in parallel so that the total cost of material handling among facilities is minimized.Since it is vital to save cost and enhance productivity,the DRLP plays an important role in many application fields.Nevertheless,it is very hard to handle the DRLP because of its complex model.In this paper,we consider a new simplified model for the DRLP(SM-DRLP)and provide a mixed integer programming(MIP)formulation for it.The continuous decision variables of the DRLP are divided into two parts:start points of double rows and adjustable clearances between adjacent facilities.The former one is considered in the new simplified model for the DRLP with the purpose of maintaining solution quality,while the latter one is not taken into account with the purpose of reducing computational time.To evaluate its performance,our SM-DRLP is compared with the model of a general DRLP and the model of another simplified DRLP.The experimental results show the efficiency of our proposed model.

A review of computerized hospital layout modelling techniques and their ethical implications

Purpose:This paper reviews an area of interdisciplinary collaboration in the design of healthcare facilities that attempts to optimize hospital space-planning using automated statistical techniques from the discipline of Operations Research(OR).This review articulates Facility Layout Problems(FLPs)as a general class of OR problems.Furthermore,the review highlights limitations of these techniques,which necessitate an ethical and participatory engagement with computerized processes of healthcare architecture.Design/methodology/approach:An in-depth critical review was carried out,which revealed a number of common themes,collectively theorized as metamodeling processes,or models of models,through which various FLP modelling techniques can be challenged and debated in terms of their architectural viability,and ethical ramifications.Findinss:This review provides a methodological basis for the further evaluation of computational models.It was found that most of the reviewed studies are functionally focused on flow efficiency and,in general,do not consider broader contextual,relational,social,or salutogenic design values.Orisinality/value:This review is the first on the subject written from an architectural perspective.It can be used by a broad range of readers as its critical review of past and present hospital layout modelling techniques discusses their capabilities and limitations.As such,it also enables them to consider ethical values while critiquing the epistemology of computational processes hidden beneath algorithmic outputs.

Using simulation in layout verification of solar module assembly workshop

Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.

Optimal Nesting for Continuous Shape Stamping Processes

WTFZ] This paper discusses the optimal nesting problem for minimizing the scrap in continuous shape stamping processes. The shape sliding technique is used to propose a new approach, OVERLAP-and-ESCAPE, to solve the problem of continuously nesting shapes onto a metal coil of fixed or selectable width. The approach is used to construct the objective function of the mathematical model of the problem using the Simulated Annealing Algorithm to determine the globally minimal configurations for the nesting problems. Some representative cases are studied and the results are encouraging. An automatic nesting software package for manufacturing bicycle chain link blanks is also described.[

Towards modeling pedestrian’s invisible trail for simulating crowd movement

Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.