This paper presents a navigation method for a mobile robot which can follow a path drawn on a monitor screen. The current position and heading direction of the mobile robot are obtained using a single camera from a single image of the guide mark projected on a convex mirror. This proposed method eliminates the need to rotate or tilt the camera to track the guide mark, because the convex mirror and a stationary camera provide a panoramic view of the surrounding area. As guide marks, fluorescent lamps on the ceiling, door frames, or any other natural line segment can be used without adding any artificial elements to them.

We study n-class-based storage policy for an automated storage/retrieval system (AS/RS) and derive the closed form expressions of expected travel times under single command cycle. In order to confirm the correctness of the derivations, we consider both discrete and continuous storage racks, and show that the expressions for expected travel times of discrete rack converge to those of continuous one. We also derive the expected travel times when the coordinate locations for storages or retrievals are triangularly distributed and we try to solve class layout problem using the obtained results. Numerical examples are given in case of 3-class-based storage policy.

In this paper, a market share competition model for two firms with asymmetric conditions is considered with. In the model, the asymmetry between two firms is given by the difference of market shares In the existing market and the change of market share is supposed to be occurred only through pioneering a new market. Since the timing decision of market pioneering is based on the continuous time domain, a super game structure which has infinitely many numbers of subgames is employed for the modeling. In the course of equilibrium finding, we show that there exists no subgame-perfect pure strategy equilibrium In this game. So, we apply a mixed strategy concept and find a unique subgame-perfect equilibrium behavior strategy. As a result of equilibrium analysis, we know that the relative sizes of pioneering Incentives between two firms are varying with parameter conditions. However, the global speed of market pioneering is proven to be independent with the level of asymmetry between two firms.

Scheduling problems which determine the sequence of jobs are one of the Important issues to many industries. This paper deals with a single-machine job sequencing problem which has complex constraints and an objective function. To solve the problem, an expressive constraint description language and an automatic code generator are developed for our scheduling system. The user just needs to describe the scheduling problem using the constraint description language that allows to express both quantitative and qualitative constraints as well as an objective function in real world semantics. Then, a complete scheduling program based on constraint satisfaction technique is automatically generated through the code generator. Advantage of this approach is that models of the scheduling problems are easily developed and maintained because models ore formulated by using the language which reflects real world semantics.

Semiconductor manufacturing line includes several batch processes which are to be controlled effectively to enhance the productivity of the line. The key problem in batch processes is a dynamic batch sizing problem which determines number of lots processed simultaneously in a single botch. The batch sizing problem in semiconductor manufacturing has to consider delay of lots, setup cost of the process, machine utilization and so on. However, an optimal solution cannot be attainable due to dynamic arrival pattern of lots, and difficulties in forecasting future arrival times of lots of the process. This paper proposes an efficient batch sizing heuristic, which considers delay cost, setup cost, and effect of the forecast errors in determining the botch size dynamically. Extensive numerical experiments through simulation are carried out to investigate the effectiveness of the proposed heuristic in four key performance criteria: average delay, variance of delay, overage lot size and total cost. The results show that the proposed heuristic works effectively and efficiently.

This paper proposes a new two-dimensional warranty policy with replacement and repair regions and analyses the warranty cost under the new warranty policy. The product is sold under a two-dimensional warranty(usage and age) in which two regions exist : the failed product is replaced by the manufacturer in the replacement region or minimally repaired by the manufacturer in the repair region. The formula of the expected warranty cost under some assumptions about usage and failure is obtained. Numerical examples are studied.

Optical fiber systems play an essential role In today's telecommunications networks. The recently standardized SONET technology has made a ring structure the preferred architecture for inter-city communication networks. In designing a SONET with ring structure, we consider inserting optional cites, which are not necessary in constructing the SONET, but cost-effective in connecting essential nodes in the ring. This problem is modeled as Steiner ring problem. Efficient heuristic procedures are developed based on the procedures for the traveling salesman problem. Computational results show that the proposed algorithm is excellent compared to the optimal solution. The error bound by the proposed method is 2 - 6% in experimented problems.

Multimedia systems present information by various media, for example, video, sound, music, animation, movie, etc., in addition to the text which has long been used for conveying the information. Among many multimedia applications, the multimedia information retrieval systems commercialized in the forms of multimedia encyclopedia CD-ROMs, benefited from various media for their ability to present information in an efficient and complete way. But using several media, on the other hand, may cause end users' confusion and furthermore, poorly designed user interface often exacerbates the situation. In this study, the multimedia systems were studied from the standpoint of usability. The conceptual framework of the user interface of the multimedia system was newly defined. And 100 initial variables for user interface design of general multimedia systems were suggested through literature survey and expert opinions based upon the framework developed. Among various application areas, the multimedia information retrieval systems were chosen for investigation, and 36 variables particularly relevant to user interface of the multimedia information retrieval systems were selected. According to the sequential research strategy, the variables that were considered to be most important were finally selected through a screening stage. A part of selected variables were verified through a human factors experiment as the first step of sequential research. Based upon the result of the experiment, guidelines for user interface design were provided. For future study, the variables remained will be Investigated and the study will expand to another application areas.

The overall performance of BISDN depends significantly on the interconnection network or the switch fabric. Hence, it is extremely important to evaluate the performance of the network or the fabric. The well developed performance models also provide insight into the factors that determine design tradeoffs as well as quantitative estimates of their importance. The objective of this paper is to investigate and critically compare all the developed performance analysis models of FPS according to internal switch fabric structure, traffic assumptions, performance measures, methodologies, etc. FPSs are described according to their internal fabric structure. Brief history of FPS performance analysis is mentioned and performance analysis modeling is discussed.

The Self Healing Ring (SHR) is one of the most Intriguing schemes which provide survivability for telecommunication networks. To design a cost effective SONET ring it is necessary to consider load balancing problems by which the link capacity is determined. The load balancing problem in SONET ring when demand splitting is not allowed is considered in this paper. An efficient algorithm is presented which provides the best solution starting from various Initial solutions. The initial solution is obtained by routing ell demands such that no demands pass through an are In the ring. The proposed algorithm iteratively improves the Initial solution by examining each demand and selecting the maximum load are in its path. The demand whose maximum arc load is biggest is selected to be routed in opposite direction. Computational results show that the proposed algorithm is excellent both in the solution quality and in the computational time requirement. The average error bound of the algorithm is 0.11% of the optimum and compared to dual-ascent approach which has good computational results than other heuristics.