Browsing by Author "Liu, FHF"

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A heuristic approach to determine bidirectional flow-path for AGV systems
(1999-06-01)
Liu, FHF
;
Chen, JT
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The rapid development of intelligent vehicles and free-ranging guide systems has increased the feasibility of practical applications for bidirectional AGV systems. This paper presents a heuristic approach for designing the flow-path layout of bidirectional automated guided vehicles. Assume that the block layout for the departments is predetermined, and that the pick-up/deposit (P/D) stations are located on the boundaries of the departments. Thus, the boundaries of the block layout can be transformed into a planar network where the nodes represent the P/D stations and the intersections of boundaries. The objective is to have a flow-path layout at minimal cost. The fixed cost of aisles and the travel cost of vehicles are considered simultaneously. There are three stages in the proposed heuristic approach: constructing an initial solution, improving the solution, and adjusting the solution. Several sample problems could be solved in less than one second using a pentium-166 PC, with less than 1% difference from the optimal solution on average. By adding some equipment for changing direction, this approach could also be applied to the material handling systems, which traverse on fixed-paths unidirectionally, such as conveyors, power-and-free, unidirectional automated guided vehicles and monorails. Significance: An effective and efficient heuristic approach is proposed for determining a bidirectional flow-path layout. The approach can be used effectively in many different divided-based configurations of AGV systems, such as tandem, segmented bidirectional single-loop (SBSL), segmented flow topology (SFT) and divided configuration.
A route-neighborhood-based metaheuristic for vehicle routing problem with time windows
(1999-11-01)
Liu, FHF
;
Shen, SY
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, a two-stage metaheuristic based on a new neighborhood structure is proposed to solve the vehicle routing problem with time windows (VRPTW). Our neighborhood construction focuses on the relationship between route(s) and node(s). Unlike the conventional methods for parallel route construction, we construct routes in a nested parallel manner to obtain higher solution quality. Valuable information extracted from the previous parallel construction runs is used to enhance the performance of parallel construction. In addition, when there are only a few unrouted customers left, we design a special procedure for handling them. Computational results for 60 benchmark problems are reported. The results indicate that our approach is highly competitive with all existing heuristics, and in particular very promising for solving problems of large size. (C) 1999 Elsevier Science B.V. All rights reserved.
A three-dimensional pallet loading method for single-size boxes
(1997-07-01)
Liu, FHF
;
Hsiao, CJ
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
The problem of finding an optimal loading layout for packing identical boxes onto a rectangular loading pallet is known as the pallet loading problem. If the boxes may be stacked on their bottom, side, or end surface, the cube utilization of a pallet will increase, but the stability of the unit load will be lost sometimes. This paper presents a method that packs rectangular boxes of the same size onto a pallet. Incorporating certain practical considerations, the method consists of five phases that maximise the degree of stability and the maximum cube utilisation of a unit load.
A three-dimensional pallet loading method for single-size boxes
(1997-07-01)
Liu, FHF
;
Hsiao, CJ
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The problem of finding an optimal loading layout for packing identical boxes onto a rectangular loading pallet is known as the pallet loading problem. If the boxes may be stacked on their bottom, side, or end surface, the cube utilization of a pallet will increase, but the stability of the unit load will be lost sometimes. This paper presents a method that packs rectangular boxes of the same size onto a pallet. Incorporating certain practical considerations, the method consists of five phases that maximise the degree of stability and the maximum cube utilisation of a unit load.
An overview of a heuristic for vehicle routing problem with time windows
(1999-10-01)
Liu, FHF
;
Shen, SY
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, a two-stage metaheuristic based on a new neighborhood structure is proposed to solve the vehicle routing problem with time windows. Our neighborhood construction focuses on the relationship between route(s) and node(s). Unlike the conventional methods for parallel route construction, we construct routes in a nested parallel manner to obtain higher solution quality. Computational results for 60 benchmark problems are reported. The results indicate that our approach is highly competitive with all existing heuristics, in particular very promising for solving problems with large size. (C) 1999 Elsevier Science Ltd. All rights reserved.
Analytical framework for designing the divided automated guided Vehicles system
(1997-06-01)
Liu, FHF
;
Chen, JT
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
The purpose of this paper is to present an analytical design framework for an AGV system configuration, called divided AGV system. In the divided AGV system, the pickup/deposit stations are divided into several transportation cells, and each cell has a simple guidepath traversed by a dedicated vehicle. Several transit stations may be set to construct a transit system for handling the intercell transport requirements. Moreover, the guidepaths for all cells are allowed to intersect at the crossroads. A systematic procedure is proposed to consider two important factors, distance and transport requirements (flow) between pickup/deposit stations simultaneously during the dividing procedure. In addition, a mathematical programming model for locating transit stations is integrated in the analytical framework. The divided configuration would not be seriously affected by plant layout, and the bi-directional vehicles would be implemented more effectively. In brief, the divided configuration could keep the simplicity of a control system and improve system feasibility and competition in a practical manufacturing environment.
Analytical framework for designing the divided automated guided Vehicles system
(1997-06-01)
Liu, FHF
;
Chen, JT
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The purpose of this paper is to present an analytical design framework for an AGV system configuration, called divided AGV system. In the divided AGV system, the pickup/deposit stations are divided into several transportation cells, and each cell has a simple guidepath traversed by a dedicated vehicle. Several transit stations may be set to construct a transit system for handling the intercell transport requirements. Moreover, the guidepaths for all cells are allowed to intersect at the crossroads. A systematic procedure is proposed to consider two important factors, distance and transport requirements (flow) between pickup/deposit stations simultaneously during the dividing procedure. In addition, a mathematical programming model for locating transit stations is integrated in the analytical framework. The divided configuration would not be seriously affected by plant layout, and the bi-directional vehicles would be implemented more effectively. In brief, the divided configuration could keep the simplicity of a control system and improve system feasibility and competition in a practical manufacturing environment.
The voting analytic hierarchy process method for selecting supplier
(2005-09-18)
Liu, FHF
;
Hai, HL
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Supplier selection has received extensive attention in supply chain management. Yahya et al. (J. Oper. Res. Soc. 50 (1999) 916-930) integrate a collaborative purchasing programme where one of the aims is to select suppliers. They illustrate a new approach based on the use of Saaty's analytic hierarchy process (AHP) method that was developed to assist in multi-criteria decision-making problems. In order to decide the total ranking of the suppliers, we compare the weighted sum of the selection number of rank vote, after determining the weights in a selected rank. This investigation presents a novel weighting procedure in place of AHP's paired comparison for selecting suppliers. It provides a simpler method than AHP that is called voting analytic hierarchy process, but which does not lose the systematic approach of deriving the weights to be used and for scoring the performance of suppliers. (c) 2004 Elsevier B.V. All rights reserved.