Location Assignment Model Research Articles

Spatial layout siting method for fire stations based on comprehensive forest fire risk distribution

In order to shorten the response time of forest fire (FF) rescue and improve the efficiency of forest fire prevention and control, this paper proposes a fire station spatial layout location method based on the spatial distribution of FF comprehensive risk. A comprehensive forest fire risk assessment model has been developed by three perspectives, namely the risk factors of forest fires, exposure degree of the disaster-bearing body, and vulnerability of the disaster-bearing body. The location-assignment model was introduced to scientifically plan the spatial layout of FF stations from different perspectives. Zhuhai in Guangdong Province, China, a typical “city surrounded by mountains,” was chosen as the research site for case analysis. The results show that the high-risk areas of Zhuhai are mainly concentrated in the forests of Xiangzhou District and Gaoxin District; the medium-risk areas mainly lie in the forests in the north of Gaoxin District, the forests of Hengqin Zone and some forests of Doumen District. Through a combination of the minimized facility point model and the maximized coverage model, it is calculated that 9 FF stations are the optimal choice, which can meet Zhuhai's demand for FF prevention and control with an acceptable construction cost and good coverage.

A dynamic storage location assignment model for a progressive bypass zone picking system with an S/R crane

We propose a storage location assignment (SLA) model that considers workload balance and recirculation reduction under a storage space restriction. The SLA model balances the weighted sum of the number of picks and the number of visits across zones to reduce the recirculation. We then extend it to a storage location reassignment (SLR) model for limited relocation capacity. When the zone picking system runs short of relocation capacity for a SLA, the SLR model moves some pairs of products, which are prioritised to maximise the SLR. Simulations of industry orders show that the SLA and SLR models reduce the order picking completion time by 9.2%∼13.6% and 5.9%∼8.9%, respectively. The results imply that the SLR model is preferable when management needs to make minimal changes to SLRs.

Effective storage location assignment model based on a genetic simulation annealing algorithm

Automated warehouses have become the main application equipment in logistics due to their access automation and simple operation. In order to adapt to the increasingly rapid logistics speed, it is necessary to optimise the location assignment of items in the automated warehouse. Firstly, according to the characteristics of the automated warehouse operation environment, the storage location assignment optimisation model with the shortest time of items travelling the warehouse, the minimum distance between related items and the lowest orthocentre of the shelf is proposed. Then according to the characteristics of the optimisation model and the shortcomings of the traditional genetic algorithm (GA), the defects of the GA are improved and the fusion with the simulated annealing algorithm (SA) is completed, so as to form an improved genetic simulation annealing algorithm (SAGA) for the model. Finally, the effectiveness and superiority of the improved fusion algorithm are verified by comparing the SA, the SAGA and the improved SAGA.

Effective storage location assignment model based on a genetic simulation annealing algorithm

Automated warehouses have become the main application equipment in logistics due to their access automation and simple operation. In order to adapt to the increasingly rapid logistics speed, it is necessary to optimise the location assignment of items in the automated warehouse. Firstly, according to the characteristics of the automated warehouse operation environment, the storage location assignment optimisation model with the shortest time of items travelling the warehouse, the minimum distance between related items and the lowest orthocentre of the shelf is proposed. Then according to the characteristics of the optimisation model and the shortcomings of the traditional genetic algorithm (GA), the defects of the GA are improved and the fusion with the simulated annealing algorithm (SA) is completed, so as to form an improved genetic simulation annealing algorithm (SAGA) for the model. Finally, the effectiveness and superiority of the improved fusion algorithm are verified by comparing the SA, the SAGA and the improved SAGA.

Multi-objective optimization of electronic product goods location assignment in stereoscopic warehouse based on adaptive genetic algorithm

Storage is an important part of commodity circulation. A certain amount of material must be stored to meet the needs of social production and consumption within a certain time to maintain the smooth process of social reproduction. This study focuses on warehousing optimization and goods location assignment when electronic products are stored in a stereoscopic storehouse. Moreover, this study is based on a theoretical study on genetic algorithm. On the basis of the background of the current warehouse management and cargo distribution of LCM module products warehouse belonging to W company, this study uses the dynamic goods location assignment strategy of stochastic inventory, and builds a multi-objective goods location assignment model of a stereoscopic warehouse. To simplify the calculations and improve the efficiency, we conduct a Matlab simulation on the basis of practical data by adopting a modified genetic operator and converting multi-objective optimization by the changing weight coefficient. The adaptive genetic algorithm can be used to make a multi-objective goods location assignment model that efficiently converges to the optimal solution.

Slotting Optimization Model and Algorithm for Concerning the Correlation in Hybrid Travel Policy

In the periodic picking background, we researched the influence of the picking correlations between Stock Keeping Units (SKUs), established dynamic location assignment model to minimize the total picking time, developed a particle swarm optimization (PSO) based on the correlated SKUs. We set the cube-per-order-index (COI) solution as initial solution, used correlation strength to update the velocity and position of particles and assigned correlated SKUs to adjacent slots according to the optimal location sequence. The result shows that in zone-based wave-picking system with hybrid touring policy, the solution quality of PSO is always better than COI, the improvement of PSO is 2.50%~13.9% and average improvement is 2.84%~12.53%; the correlation has significant impact on the picking efficiency.

The Potential Deployment Of Set Covering And Location-Assignment Model: The Case Of Locating Trauma Centers At The Midwest Region

The Midwest Trauma centers case illustrates how the application of set covering can be used in locating trauma centers in the Midwest region. It shows the students how to develop a linear programming spreadsheet model with binary variables to find the minimum number of trauma centers locations that can cover the major cities in the Midwest. Students completing the case will be able to develop a model which decides the locations of trauma centers that will maximize the total number of people covered within a certain distance. This case will present a linear programming model that will solve a set covering and location assignment problem. The application of Excel Solver and Solver Table will help students answer many what if questions. This case will also enrich students’ knowledge on how to build the model entirely throughout the spreadsheet without the need to formulate the model algebraically.

Design and Simulation of Storage Location Optimization Module in AS/RS Based on FLEXSIM

This paper firstly points out the importance of the storage location optimization in Automated Storage and Retrieval Systems (AS/RS). Then it has analyzed the basic situation of the current storage location assignment strategy, and indicated the deficiency of the storage location selection under the current strategy. Afterwards, it has designed the storage location optimization module in AS/RS. And then it has constructed the mathematical model on the storage location assignment in AS/RS, and then optimized and solved it, performed instance simulation design and analysis on the storage location assignment by means of Flexsim. Finally, it has concluded that the storage location assignment model after optimization would solve the storage location assignment problem in AS/RS effectively and improve the loading-unloading efficiency, as will provide technical support for the enterprise to improve efficiency and reduce cost.

Local public goods, property values, and local public choice

This paper examines the relationship between the benefits and costs of local public good provision and local property values within the context of the Koopmans-Beckmann-Gale location-assignment model. Property values do not in general measure accurately the marginal net benefits of local public goods; special conditions sufficient for property values to measure or bound the marginal net benefits are stated, however. In addition, it is shown that under certain circumstances, households vote for property-value-enhancing levels of local expenditures. Under these conditions, a political equilibrium produces a Lindahl solution to the local public good problem.