• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.384-391
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• 2000

Most of the previous works on classical location models are based on the assumption that the value(or utilities) of inventory remains constants over time. In this study a special case of location problem is studied for both ameliorating and deteriorating items in two-echelon supply-chain management such as agricultural and fishery products. The objective of this study is to determine the minimum number of storage facilities among a discrete set of location sites so that the probability for each customer to be covered is not less than a critical value. We have formulated this problem using stochastic set-covering problem which can be solved by 0-1 programming method. Also we developed a computer program and applied to a set of problems for fish culture storage and distribution centers and the sample results well show the impact of ameliorating and deteriorating rate on the location problem. For the further study, a graphical user-interface with visualization for input and output is needed to be developed.

• Journal of Korean Society for Quality Management
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• v.30 no.4
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• pp.26-43
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• 2002

This study was conducted to identify the differences in service quality between Incheon and Kimpo international airports and critical factors influencing satisfaction of their customers. According to the results of the study, all service quality factors of Incheon international airport except the service factor of geographical location were better than those of Kimpo international airport. However, all service quality factors of the two airports were evaluated inferior to those of American, western European and Japanese international airports. In addition the service quality factors such as response, safety, airport facility and geographical location were found as critical factors influencing satisfaction of the airport customers. The service quality factor of geographical location of Incheon international airport was measured much inferior comparing with other service quality factors. Thus, the results of this study suggest that the Korean government deliberate and benchmark the international airports of western Europe and the USA in determining the geographical location when planning new international airports.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.473-476
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• 1996

In order to reduce the number of rehandles during the loading operation of export containers in port container terminals, the storage location of each arriving container should be determined considering of its weight. We formulate the problem by a dynamic programming model to get the optimal storage location.

• Journal of the Korean Operations Research and Management Science Society
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• v.12 no.2
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• pp.36-41
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• 1987

This paper presents a heuristic algorithm for solving the simple facility location problem. Its main procedure is essentially of 'add' type, which progressively selects facilities to open according to a certain criterion derived from the analysis of the linear programming dual. Computational experience with test problem from the literature is presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.316-319
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• 2008

Most of campus vehicle management systems, so far, have simple functions such as managing vehicle in/out or issuing parking tickets. Recently some of them use RFID tags to count total numbers of cars in the campus, excluding exact parking position management. In this paper we propose a new campus vehicle management system using wireless sensor network location management scheme. This system adopts RSSI based location management method with some performance improvement technique. According to the experimental result, this proposed scheme can be used to implement an effective campus vehicle management system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.999-1004
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• 2010

Most of campus vehicle management systems, so far, simply manages coming in or go out of vehicles, issuing a parking tickets. Recently some of them use RFID tags to count total numbers of cars in the campus, excluding exact parking position management. In this paper we propose a new campus vehicle management system using wireless sensor network location management scheme. This system adopts RSSI based location management method with some performance improvement technique. According to the experimental result, this proposed scheme can be used to implement an effective campus vehicle management system.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.31-42
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• 2011

Smart-Phones are utilized in disaster management field because it can deliver disaster information to large population simultaneously and quickly, and provide accurate information through situation-based service using the LBS(Location Based Service). To study on the utilization of smart phone for disaster information collection and dissemination method, this study suggest a framework which connects smart phone by loading application for reporting disaster. The disaster monitoring and situation dissemination system framework using smart phone is composed of 4 parts. First, smart phone application enters image, video, voice and text information and location of the disaster. Second, the disaster report reception and situation dissemination server receives the information, save in the DB, and send through smart phone SMS. Third, store into disaster information database. Fourth, display the disaster report and management information on 2D GIS, support the decision making process in deciding whether to manage as disaster, and disaster management web service which disseminates situation.

• Journal of Preventive Medicine and Public Health
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• v.29 no.2 s.53
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• pp.215-225
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• 1996

Decentralization to local governments and amending of Health Center Law are to promote the efforts of health planning at the level of local agencies. In the health facility planning, it is important to take into account that what to be built, where to be located, how far should be service area and so forth, because health facilities are immovable, and require capital as well as personnel and consumable supplies. The aim of our study, answering to the question of 'where to be located?', is to determine the best location of urban health sub-center. At the local level, planning is the matter of finding the best location of specific facilitiy, in relation to population needs. We confine the accessibility, which is basic to location planning, to geographic one. Location-Allocation Model is used to solve the problem where the location is to maximize geographic accessibility. To minimize the weighted travel distance, objective function, $R_k=\sum{\sum}a_{ij}w_{i}d_{ij}$ is used. Distances are measured indirectly by map measure-meter with 1:25,000 Suwon map, and each potential sites, 10 administrative Dongs in Kwonson Gu, Suwon, are weighted by each number of households, total population, maternal age group, child age group, old age group, Relief for the livelihood, and population/primary health clinics. We find that Kuwoon-Dong, Seodun-Dong, Seryu3-Dong, according the descending orders, are best sites which can minimize the weighted distance, and conclude that it is reasonable to determine the location of urban health sub-center among those sites.

• Journal of Computing Science and Engineering
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• v.4 no.2
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• pp.173-187
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• 2010

Recent technological advances in mobile communication systems have made explosive growth in the number of mobile device users worldwide. One of the most important issues in designing a mobile computing system is location management of users. The hierarchical systems had been proposed to solve the scalability problem in location management. The scalability problem occurs when there are too many users for a mobile system to handle, as the system is likely to react slow or even get down due to late updates of the location databases. In this paper, we propose a top-down clustering algorithm for hierarchical location database systems in a wireless network. A hierarchical location database system employs a tree structure. The proposed algorithm uses a top-down approach and utilizes the number of visits to each cell made by the users along with the movement information between a pair of adjacent cells. We then present a modified algorithm by incorporating the exhaustive method when there remain a few levels of the tree to be processed. We also propose a capacity constraint top-down clustering algorithm for more realistic environments where a database has a capacity limit. By the capacity of a database we mean the maximum number of mobile device users in the cells that can be handled by the database. This algorithm reduces a number of databases used for the system and improves the update performance. The experimental results show that the proposed, top-down, modified top-down, and capacity constraint top-down clustering algorithms reduce the update cost by 17.0%, 18.0%, 24.1%, the update time by about 43.0%, 39.0%, 42.3%, respectively. The capacity constraint algorithm reduces the average number of databases used for the system by 23.9% over other algorithms.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.33-40
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• 2017

In this paper, we propose a sink-location management and data-routing scheme to effectively support the mobile sink in solar-powered WSN. Battery-based wireless sensor networks (WSNs) have a limited lifetime due to their limited energy, but solar energy-based WSNs can be supplied with energy periodically and can operate forever. On the other hand, introduction of mobile sink in WSNs can solve some energy unbalance problem between sink-neighboring nodes and outer nodes which is one of the major challenges in WSNs. However, there is a problem that additional energy should be consumed to notify each sensor node of the location of the randomly moving mobile sink. In the proposed scheme, one of the nodes that harvests enough energy in each cluster are selected as the cluster head, and the location information of the mobile sink is shared only among the cluster heads, thereby reducing the location management overhead. In addition, the overhead for setting the routing path can be removed by transferring data in the opposite direction to the path where the sink-position information is transferred among the heads. Lastly, the access node is introduced to transmit data to the sink more reliably when the sink moves frequently.