Kazuho Yoshimoto

Heuristic algorithm to solve the multi-floor layout problem with the consideration of elevator utilization

This paper presents an algorithm to get a solution of the facility layout problem for multiple-floors. In a number of previous research, these problems are formulated as a combinatorial optimization problem to minimize only the cost owing to material flow between departments ignoring the utilization of the elevators, which is a typical transportation equipment for vertical transportation. In our proposed algorithm, the capacity of elevators is taken into consideration. Then the proposed algorithm optimizes the number and location of elevator with the consideration of the assignment of each carriage to the elevators. Numeric results are given to demonstrate the effectiveness of the proposed algorithm.

A dispatching method for automated guided vehicles by using a bidding concept

A dispatching method is suggested for automated guided vehicles by using an auction algorithm. The dispatching method in this study is different from traditional dispatching rules in that it looks into the future for an efficient assignment of delivery tasks to vehicles and also in that multiple tasks are matched with multiple vehicles. The dispatching method in this study is distributed in the sense that the dispatching decisions are made through communication among related vehicles and machines. The theoretical rationale behind the distributed dispatching method is also discussed. Through a simulation study, the performance of the method is compared with that of a popular dispatching rule.

A construction algorithm for designing guide paths of automated guided vehicle systems

A construction algorithm is suggested to design guide path networks for automated guided vehicle systems (AGVSs). This study uses the total travel time, including waiting and interference time, of vehicles as the decision criteria for determining the direction of path segments on unidirectional guide path layouts. The Q-learning technique is applied to estimate the travel times of vehicles on path segments. Computational experiments were performed to evaluate the performance of the proposed algorithm. The simulation results showed that the proposed algorithm is superior to Kim & Tanchocos (1993) algorithm in terms of the average travel time, the interference time and the number of deliveries.

Solving Facility Layout Problem via Particle Swarm Optimization

This paper targets the Facility Layout Problem (FLP), which has many practical applications and known to be NP-hard. During recent decades, a number of algorithms have been proposed to solve this problem. Most of those algorithms try to solve this problem by encoding layout candidates and using combinational optimization techniques to obtain the best one among those encoded candidates. However, since there exist layouts which cannot be represented by those encoding techniques, there is possibility of missing the searching opportunity for the optimal solution. To overcome this problem, this paper is concerned with the development of algorithm to solve FLP by searching continuously optimal coordinate of each department. In particular, this paper proposes an algorithm solving FLP via Particle Swarm Optimization (PSO), which is known to be effective for many types of continuous optimization problem.

Designing guide-path networks for automated guided vehicle system by using the Q-learning technique

This paper suggests a Q-learning technique for designing guide-path networks for automated guided vehicle systems. This study uses the total travel time as the decision criteria for constructing guide-path layouts. The Q-learning technique is applied to the estimation of the travel time of vehicles on each segment of the guide-path. Computational experiments were performed to evaluate the performance of the proposed algorithm. The simulation results showed that the proposed algorithm is superior to Kim and Tanchocos (1993) in terms of average travel time, interference time, and number of deliveries.

Application of Integrative Analytic Hierarchy Process and 0-1 Integer Programming to Retail Stores Location in Logistic System

Location of retail stores in logistic system involves many factors, some of which are quantitative, others of which are qualitative. The weight of each retail place is calculated by using AHP on the basis of analyzing the factors, then a location model is proposed by combining AHP and 0-1 programming, for AHP can not solve the problem with constraint. Finally the model of retail place location in logistic system is proved to be effective by examples.

Application of AHP/DEA to Facility Layout Selection

Facility location selection is a multi-criteria decision problem and has a strategic importance for many companies, so it is very important to select alternative locations using appropriate methods. The aim of this study is to use analytic hierarchy process (AHP) and pure output data envelopment analysis (DEA) methods for facility location selection. After determining the factors that affect the facility location decisions, pure output DEA is used to construct the comparison matrix, then AHP is applied to calculate the weights of the alternative locations. In this method the known data is fully used and the influence of personal factors is avoided. Finally an example is illustrated to prove the method effective.

A 3D plant layout model considering pipeline route arrangement

We have developed a three-dimensional plant layout model considering I/O points and pipeline route arrangement. It is known that the much of operating costs in a typical industrial plant can be attributed to layout and pipeline design, and thus, the computer-aided layout has been studied to help layout planners consider various alternatives in a very short time. In this paper, we proposed a two-phase method: layout arrangement and pipeline arrangement. In the layout arrangement, we use continuous representation model for simplicity and accuracy, using MIP-based formulation. We apply particle swarm optimisation (PSO) to get a preferred set of relative-positioning of equipments quickly. We then optimise the layout arrangement under the specified relative-positioning. In the pipeline arrangement, we cast the plant layout into the graph representation. To cast layout representation, we propose graph creation technique called ‘3D min-max method’ that enables us to project nodes and arcs onto the obtained layout. We then set the pipeline route onto the shortest path between equipment, using Dijkstra’s method. In the numerical experiments, we show how our method can be applied to industrial application.

Multi-floor facility layout optimization using Slicing Tree Structure

This paper presents an algorithm for solving a multi-floor facility layout problem. The most apparent difference and also the potential difficulty in a multi-floor facility layout problem, compared to a single floor facility layout problem, are the problems regarding the placement of the vertical transportation equipments (elevators), which are to be used for vertical transportation occuring within the facility. Many solutions generated by algorithms presented for the multiple floor layout problems in the past had problems : irregular-shaped workshops and/or unnecessarily large unusable space (=dead space) within the facility. In this paper, we implement and improve Slicing Tree Structure for generating layout. Layout generated by using Slicing Tree Structure has a unique characteristic of making no dead spaces within the facility at all. We will present an algorithm, which generates near-optimal layout of workshops and elevators in a facility without dead space by improving the structure of Slicing Tree.

A Layout Technique for Multiple Floor Layout Problem Considering the Area of an Elevator

This paper presents a layout technique for the multiple floor layout problems. Compared with the carriage in horizontal way, the carriage in vertical way needs more cost dramatically and gets complicated with the assignment for each carriage, because of using vertical transportation equipment such as elevator. Then we need multiple floor layout algorithms that consider proper location and number of vertical transportation equipment. We considered about the area of elevator inside the facility and several kinds of vertical transportation equipment, draw up the approximate optimum layout by Space Filling Curve, examine the possibility about the layout in practice consideration about timing of production, and suggest more realistic multiple floor layout algorithm.