A tandem AGV system is based on partitioning all the stations into non-overlapping single vehicle closed loops with additional stations provided as an interface between adjacent loops. For an efficient use of this configuration, it is required to solve the load routing problem(LRP), which is primarily based on the fact that a load may be handled by several vehicles and moved through several loops before it reaches its destination. In this paper, a heuristic based on genetic algorithm(GA) is first developed to solve LRP. The first model obtains the optimal route of each job and the optimal direction of each loop when the vehicle in each loop travels unidirectionally. The second GA model obtaines the optimal polling sequence of the empty vehicle in each loop, when the vehicle can move bidirectionally.

Virtual manufacturing is a technology facilitating effective development and agile manufacturing of products via sophisticated computer models representing physical and logical schema and behavior of real manufacturing systems including manufacturing resources, environments, and products. Based on these models, virtual manufacturing supports decision making and error checking in the entire manufacturing processes from design to mass production. At first, we analyzed manufacturing preparation activities of the four major production shops such as press, body assembly, painting and final assembly, of a Korean automotive company. We then developed the workflow models out of the analysis by the IDEF methodology, and generated a strategic plan for the systematic application of the virtual manufacturing technologies. We identified many manufacturing preparation activities that can be improved by the application of virtual manufacturing technologies. Finally, we estimated the effect of improvement including time savings in car development processes and corresponding cost savings.

Virtual Manufacturing is a technology facilitating effective development and agile production of products via computer models representing physical and logical schema and the behavior of the real manufacturing systems. For the successful application of this technology, a virtual plant as a well-designed and integrated environment is essential. We propose a series of systematic approaches and effective methods for construction and operation of a virtual plant in this paper, such as a 3-D CAD modeling, cell and line simulations and databases. We developed key technologies for measuring and 3-D CAD modeling of many equipments, facilities and structures of the buildings. In order to study the benefit of virtual manufacturing, we constructed a sophisticated virtual plant model of a Korean automotive company's body shop, and conducted precise simulations of unit cell, lines and the whole plant. We could obtain the benefit of savings in time and cost in many manufacturing preparation activities in the new car development processes.

This paper describes an automatic design system for the parts that compose the power transmission. Power transmission is composed of shaft, gear, clutch, brake and housing. To design power transmission, there are many recurrent calculations and drawings needed with conventional design process. In this paper, we propose three dimensional automatic design system that reduce recurrent calculations and drawings. Developed system consists of two modules; 1) Design expert system module to assist determining design parameters of clutch, brake and gear. 2) Parametric modeling module to make three dimensional solid model automatically. The proposed system has been tested in the fields and found to be a useful system.

In the turbine-blade manufacturing industry, turbine-blades are machined and then are assembled to form a circular roll of blades. The roll of blades should be balanced as much as possible, since otherwise the efficiency of the turbine generator might be damaged. A locking blade is a blade whose location is fixed and a non-locking blade is a blade whose location can be freely changed. In this paper, we study methods for balancing the weights of the rotating blades for a turbine where some blades are locking blades. The turbine-blade balancing problem is formulated into a mixed-integer programming problem, which turns out to be NP-hard. A heuristic method based on the number partitioning algorithm is developed and the computational experiments show very promising results.

This paper considers a network restoration algorithm for all-optical WDM networks. As the increasing traffic and transmission speed, any failure on the networks will lead to loss of huge data and disruption of the services. Therefore, a network restoration algorithm is necessary for the high-speed all-optical networks. This paper suggests a distributed restoration algorithm for line or channel level failures under the dynamic rerouting. For the algorithm, some measures for performance evaluation are explicitly derived and simulation studies are exploited to evaluate its usability by SLAM(Simulation Language for Alternative Modeling) II.

The paper describes disassemblability evaluation method using axiomatic approach. In recent industry, it is necessary to develope high recyclable environmental product due to green consumer and environmental regulations. Disassembly stage is prior to recycling. Disaassembly time data is determined previously in order to calculate the disassembly segments and disassembly sequence. In this paper the evaluation method of disassembly segment/sequence and disassembly time database are suggested. A case study of monitor product was showed.

We suggest a Business Performance Information System with Knowledge Discovery in Databases(KDD) as a key component of integrated information and knowledge management system. The proposed system measures business performance by considering both VA(Value-Added), which represents stakeholder's point of view and EVA(Economic Value-Added), which represents shareholder's point of view. In modeling of Business Performance Information System, we apply the following KDD processes : Data Warehouse for consistent management of a performance data, On-Line Analytic Processing(OLAP) for multidimensional analysis, Genetic Algorithms for exploring and finding dominant managing factors and Analytic Hierarchy Process(AHP) for applying expert's knowledge and experience. To demonstrate the performance of the system, we conducted a case study using financial data of Korean automobile industry over 16 years from 1981 to 1996, which is taken from database of KISFAS(Korea Investors Services Financial Analysis System).

Application Service Provider(ASP), the service provider who manages and delivers standard application functionality or associated service across a network to multiple customers using a usage-based pricing model, has appeared as a new business style in information technology market. For successful implementation of the ASP model, some critical issues should be noted. Because these issues are related to service qualities, certification and audit of ASP are important. This paper investigates characteristics of the ASP model and designs the proper frameworks for certification and audit of ASP. It is examined how the framework can remove potential threats and risks of the ASP model, and how the framework can be compared with traditional approaches.

Recently the number of wireless internet service user is increasing rapidly but there are some areas in which service level has not reached the expected level yet. In this paper, we apply ACSI model to measure the current level of customer satisfaction. As a result of ML estimation, we observe that satisfaction increases as the level of perceived quality increases. However, this model does not provide flexibility of adjusting data characteristics that wireless internet service has, and it is not easy to find direct controllable feedback for better service. We propose a structural equation model that can overcome these problems and obtain that information transmission quality and proper fare policy can significantly improve the satisfaction level of wireless Internet users.

Growth curves including Logistic and Gompertz functions are widely used in forecasting the market demand. To estimated the parameters of those functions, we use the non-linear least square method. However, it is difficult to set up the starting points for each parameter. If a wrong starting point is selected, the result reveals the local optimum or does not converge to a certain value. The purpose of this paper is to resolve the problem of selecting a starting point. Especially, rescaling the market data using the national economic index make it possible to figure out the range of parameters and to utilize the grid search method. Applications to some real data are also included.

The ISO 9000 family of international quality management standards were revised on 15 December 2000. The ISO 9001:2000 standard is used for certification/registration and contractual purposes by organizations seeking recognition of their quality management system(QMS). We summarize key contents changed in ISO 9000:2000 family standards. To comply with ISO 9001:2000, we analyze the current QMS for steel outfit industry, using audit results from ISO 9001:1994 for seven steel outfit firms during last three years. We investigate statistical relationships between ISO 9001:2000 and ISO 9001:1994 requirements from a three dimensional contingency table with audit results. We observe that the importance of requirements of the ISO 9001:2000 sections makes a difference between companies.

The number of tunnel has fast increased with the rapid expansion of highway network. Tunnel should be designed to provide for drivers both safety and pleasant driving conditions. In this perspective, the design for tunnel lightning is very important in order to provide its safety, pleasantness, and cost-efficienty of maintenance, all of which should be considered and analyzed for a better tunnel lighting. This paper attempts to compare the low-pressure sodium lamp, which has usually been used for tunnel lighting, with the fluorescent lamp, which we consider as an alternative for the former. In an effort to determine the number of lamps to meet the required illuminance in the tunnel, this research employs a simulation technique which would allow us to conjecture, with the aid of basic model, the life cycle cost for illumination per each tunnel. This analysis is expected to provide a basic method and related information for tunnel development and design.

Because passenger seat is one of the most important parts in the determination of passengers' satisfaction for train, it is absolutely important to design the passenger seat so that train passengers can satisfy. So, in the seat design it is necessary to consider passengers' characteristics, requirements, and dissatisfactions. However, passengers' dissatisfactions for the seat of Mugunghwa-ho train have been often raised through various routes. It is necessary to resolve their dissatisfactions to provide comfortable trip to passengers. So, we designed a new seat of Mugunghwa-ho train that resolved passengers' dissatisfactions. Our focusing design parts were the seat pan and the backrest of passenger seat. We investigated passengers' dissatisfactions for the seat of Mugunghwa-ho train through various methods and the human factors design guidelines through literature survey. We designed a new seat on the basis of investigated results. For newly designed seat, we evaluated comfort and sensible satisfaction in comparison with the existing seat. An experimental method and subjective methods were used in this evaluation. In all aspects, the new seat was superior to the existing.