Layout Optimization Model Research Articles

Study on Multi-Objective Optimization Model for VMS Layout on Expressways

In order to determine layout location of variable message signs (VMS) scientifically and reasonably and give full play to its transportation guidance effect, the optimal selection method of expressways VMS layout location is studied based on general rules and requirements of expressways network VMS layout. Construct the multi-objective optimization model of VMS information utilization maximum, VMS effectiveness and VMS total cost minimum based on fuzzy constraint conditions, and the Hang-Jin-Qu expressway VMS layout is analyzed. The results show that the proposed multi-objective optimization model is more in line with the actual need of VMS layout and easy to operate, and has important practical value.

The Application of Layout Heuristic Optimization Algorithm in Operational Model

In order to solve the layout NP complete problem, this paper analyzes the layout optimization model and algorithm, This kind of problems involved in operational research, data structures, algorithm analysis, artificial intelligence, computer network, etc. multi-discipline knowledge. Layout problems widely exist in practice, the main research rectangular optimal layout, Rectangular optimal layout is a series of rectangular parts reasonably emissions in raw material, make the highest utilization of raw material, And the optimization mathematical model is established, and the use of heuristic algorithm to solve the rectangular optimal layout problem. Simulation experiment showed that the optimization algorithm is effective.

Based on GIS Technology of Urban Gardening and Greening Layout Optimization Model

With the accelerated process of urbanization, city environment problems are highlighted, city landscape and city modernization phase matching. However, the urban gardening and greening is difficult to optimize the layout, with the new city landscape green area increased every year, which will make the City Landscaping Administration difficulty. In this study, detailed analysis of GIS technology development trend as well as in the city green space applications, which is supported by GIS technology, integrated distribution of population, manpower, material resources and financial resources, city greening planning design, construction, transportation cost and the maintenance management and other comprehensive factors, application technology based on GIS mesh accessibility calculation method, exploring the construction of urban gardening and greening layout optimization model of city landscape green space, spatial distribution characteristics and verify the layout optimization model is feasible and practical, in order to strengthen the city landscaping work play a role.

Product Layout Optimization and Simulation Model in a Multi-level Distribution Center

We consider the product allocation problem in logistics engineering, which allows incorporating various aspects in horizontal and vertical direction. These aspects include carrying time, the turnover rates of products, relevance of product demand, elevator waiting time, vertical transportation time, etc. we develop a 0-1 programming model with two objectives-minimization of total transportation time and maximization of relevance of product demand. In order to obtain average waiting time of every level, we establish an elevator simulation model considering the limitation of elevator capacity. The proposed optimization model can be solved using Genetic algorithm heuristically. A numerical example shows its effectiveness.

Layout Design of Naval Gun Magazine Based on Improved GA

In this paper a magazine layout optimization model with performance constraints is described and the objective function and its constraints of magazine layout are established. A multiobjective optimizations layout model based on polygon method is put forward. The model deals with a series of constraints such as geometry constraints, in-and-out point position optimization, magazine capacity and system reliability and safety. An improved genetic algorithm (GA) is proposed in this paper based on the new encoding scheme and logical mutation operator. The algorithm solved the problem of multiobjective layout design with performance constraints.

New Mathematical Optimization Model for Construction Site Layout

Layout of temporary construction facilities (objects) is an important activity during the planning process of construction projects. The construction area layout is a complex problem whose solution requires the use of analytical models. Existing popular models employ genetic algorithms that have proven to be useful tools in generating near optimal site layouts. This paper presents an alternative approach based on mathematical optimization that offers several important features and generates a global optimal solution. The construction area consists of an unavailable area that includes existing facilities (sites) and available area in which the objects can be located. The available area is divided into regions that are formulated using binary variables. The locations of the objects are determined by optimizing an objective function subject to a variety of physical and functional constraints. The objective function minimizes the total weighted distance between the objects and the sites as well as among the objects (if desired). The distance can be expressed as Euclidean or Manhattan distance. Constraints that ensure objects do not overlap are developed. The new approach, which considers a continuous space in locating the objects simultaneously, offers such capabilities as accommodating object adjacency constraints, facility proximity constraints, object–region constraints, flexible orientation of objects, visibility constraints, and nonrectangular objects, regions, and construction areas. Application of the model is illustrated using two examples involving single and multiple objects. The proposed model is efficient and easy to apply, and as such should be of interest to construction engineers and practitioners.

A two-step algorithm for layout optimization of structures with discrete variables

This paper presents a mathematical model for Layout optimization of structure with discrete variables. The optimization procedure is composed of two kinds of sub-procedures of optimization: the topological optimization and the shape optimization. In each one, a comprehensive algorithm is used to treat the problem. The two kinds of optimization procedures are used in turn until convergence appears. After the dimension of the structure is reduced, the delimiting combinatorial algorithm is used to search for the better objective value. A couple of classical examples are presented to show the efficiency of the method. Numerical results indicate that the method is efficient and the optimal results are satisfactory.

Establishing an Optimization Model for Sewer System Layout with Applied Genetic Algorithm

In this study, a genetic algorithm (GA) is first used to establish a combinatorial optimization model, called the Sewer System Optimization Model for Layout & Hydraulics (GA/SSOM/LH), to find an optimal for a real urban sewer system. The problems of and design optimization are considered simultaneously. The modeling concept is to combine the fundamental principles of the GA, to the generation of possible network layouts as well as to develop a design optimization module, the Sewerage System Optimization model (SSOM), which can find the best sewer system layout by checking the overall least-cost hydraulic of several possible alternate network layouts. SSOM is a 0-1 Mixed Integer Programming (MIP) in which a traditional algorithm, the Bounded Implicit Enumeration (BIE) is applied to determine the optimal size and slope for each. Unlike the BIE algorithm, 'one chromosome' in the GA evolution is coded to represent 'one system layout' parameter. Specific coding strings on 'parameters' are operated directly and are more robust when combined with the SSOM module. Hence the GA can evolve quickly generating an optimized system layout and ensuring a solution closer to the global optimum in a 'fast' manner. Finally, a case study was conducted on a 73-node project to verify the optimal system layout as generated by the GA/SSOM/LH model.

The global optimal solution to the three-dimensional layout optimization model with behavioral constraints

In this paper we study the problem of three-dimensional layout optimization on the simplified rotating vessel of satellite. The layout optimization model with behavioral constraints is established and some effective and convenient conditions of performance optimization are presented. Moreover, we prove that the performance objective function is locally Lipschitz continuous and the results on the relations between the local optimal solution and the global optimal solution are derived.

Compliance based MIP model and heuristic for support layout optimization

Machining-fixture supports are used to increase workpiece rigidity. A critical problem of machining fixture design is where to place a fixed number of supports in order to minimize the affect of workpiece deformation on machined feature geometric error during machining. In a previous effort, a linear Mixed Integer Programming (MIP) model was developed to solve this problem. This model is based upon a statically reduced FEA model of the workpiece, and is capable of solving the more general problem of locator button-support layout. A major disadvantage of this model is that its size is sensitive to the square of the number of machining response points considered. Since the difficulty of solving an MIP model increases with model size, this presents a severe limitation to the use of the MIP model in applications in which a large number of machining response points must be considered. This paper illustrates a technique that can be used to make the MIP model size strictly proportional to the number of machining response points. In addition, it presents a heuristic based on the MIP model, that can be used to solve support layout problems of any size.

Improved workpiece location accuracy through fixture layout optimization

Inaccuracies in workpiece location lead to errors in position and orientation of a machined feature on the workpiece. The ability to accurately locate a workpiece in a machining fixture is strongly influenced by rigid body displacements of the workpiece caused by elastic deformation of loaded fixture–workpiece contacts. This paper presents a model for improving workpiece location accuracy in fixturing. A discrete elastic contact model is used to represent each fixture–workpiece contact. Reduction in workpiece locating error due to rigid body displacements is achieved through optimal placement of locators and clamps around the workpiece. The layout optimization model is also shown to improve the overall workpiece deflection and reaction force characteristics.

Fast support layout optimization

Machining-fixture supports are used to increase workpiece rigidity. A critical problem of machining-fixture design is where to place a fixed number of supports in order to minimize workpiece deformation during machining. This paper presents the Fast Support Layout Optimization (FSLO) model. The objective of the FSLO model is to determine support locations that will minimize the maximum displacement-to-tolerance ratio of a set of workpiece features subject to a system of machining loads. The FSLO model utilizes a Finite Element Analysis (FEA) model to characterize workpiece stiffness. Solution of the FSLO model improves an existing support layout by systematically altering the boundary conditions applied to the FEA model. The FSLO model is unique in that its solution time is both very small and insensitive to the size of the FEA model, the sizes of machined features considered, and the sizes of the candidate regions of the supports. In addition to describing the formulation of the FSLO model, this paper describes a set of experiments that were used for its verification.