Akiko Shinozaki

Hybrid Design Methodology and Cost-Effectiveness Evaluation of AGV Transportation Systems

In this paper, we analyze and compare the performance of the vertical and the horizontal automated-guided-vehicle transportation systems. We use results in queuing network theory and a transportation simulator to design a hybrid strategy for this study, and to set the appropriate number of agents in the systems. Next, these two transportation systems are evaluated based on cost-effectiveness criteria. For this purpose, the total construction costs of the systems for the various transportation demands are compared. Finally, we provide analytical results to evaluate and to obtain the most efficient system, based on the validity of each system, under different demand scenario. Note to Practitioners-A good design methodology is essential for the study of the optimal layout in an automated container terminal. Port designers need to select the most efficient automated-guided-vehicle (AGV) transportation system, and to set the appropriate number of agents operating in the system. This study presents a hybrid design methodology and a cost-effectiveness comparison of the vertical and the horizontal transportation systems. Our proposed design methodology is able to derive the combinatorial optimal design solutions rapidly, and at the same time pin point the bottleneck in the system. This proposed methodology can be easily applied to any transportation or logistics system, provided the system can be divided into components represented as nodes in a graph. Our results demonstrate that the horizontal AGV transportation system is more effective than the vertical AGV transportation system under most demand scenarios.

Highly efficient AGV transportation system management using agent cooperation and container storage planning

The development of a highly efficient management methodology for an automated container terminal (ACT) poses a problem for port authorities. The focus here is on a transportation system for an automated guided vehicle (AGV) for an ACT. In this paper, we design the detailed management models, i.e., agent cooperation and container storage planning for the transportation system. Then, we optimally design systems that are constructed with the use of the designed management models. Comparisons of the systems are made to evaluate cost effectiveness based on the total construction cost and validity of the management models. Finally, a proposal is made for the most efficient management system.

Optimal Design Methodology for an AGV Transportation System by Using the Queuing Network Theory

In this paper, we propose an optimal design methodology for an AGV transportation system by using the queuing network theory. In this study, we deal with an actual transportation system as a combinatorial optimization problem. Therefore, some kind of paths and working multi-agents, such as Automated Guided Vehicles (AGVs), Automated Transfer Cranes (ATCs), and container cranes, are included in this system as design objects. We describe how to derive these design parameters (i.e., design solutions) by the performance evaluation of an AGV transportation system.

Improved design methodology for an existing automated transportation system with automated guided vehicles in a seaport container terminal

In this paper, we propose an improved design methodology to meet the changing demands of an existing automated container transportation system in which automated guided vehicles (AGVs) are used. This system is called an AGV transportation system. To achieve an improved design, it is essential to detect and correct any occurring bottlenecks. For this purpose, we exhaustively enumerate design proposals by constructing a logic tree. As a case study to verify the proposed methodology, we apply the methodology to an existing AGV transportation system. From the enumerated design proposals, we suggest design policies by considering the actual constraints of the transportation system. Finally, we redesign the transportation system as rapidly as possible. On the other hand, we keep system balancing into account; then, we derive a suitable demand and input number of AGVs under given specifications for a transportation system.

Comparison of an AGV transportation system by using the queuing network theory

In this paper, we provide the comparison indicator of the AGV transportation systems. For this purpose, we propose an optimal design methodology for the AGV transportation system by using the queuing network theory. In this methodology, the queuing network theory and a simulation-based optimization method are integrated to obtain the optimal design parameters (i.e., these are the design solutions of this design problem). In this study, two different types of the AGV transportation systems are designed. Then the performance of transportation is compared. Finally, the characteristic of each transportation system that depends on the design parameters is provided.

Optimal Design, Evaluation, and Analysis of AGV Transportation Systems Based on Various Transportation Demands

In this paper, two designs for optimal Automated Guided Vehicle (AGV) transportation systems are presented. One is vertical and the other, horizontal. For these systems, the hybrid design methodology proposed here is used. Therefore, we describe how to model and formulate these transportation systems and derive the design parameters, that is, the optimal design solutions. We next evaluate these two transportation systems based on the various transportation requirements, that is, the demands from a port authority. For this purpose, we compare the systems based on the total costs in constructing them. Finally, the evaluation and analytical results are provided, and the most convenient system is presented based on the validity of each system for the given demand.

LOW-COST AND ROBUST POSITIONING SYSTEM FOR INDOOR GROUP OF FORKLIFTS UTILIZING PROBABILITY ESTIMATION AND SENSOR NETWORK

A position management system for forklifts involved in a warehouse storage task is proposed. With a simple, low-cost laser beam sensor and reflective stickers, the position of the forklift can be established. Furthermore, by combining probability estimation algorithms, the possible location of forklifts can be managed, and the accuracy of positioning can be improved through the exchange of information on a sensor network. Finally, the layout, which has a better system performance, is also discussed and proposed. With this system, forklift operations are easier, and the cost of a warehouse navigation system decreases.