• Journal of Computing Science and Engineering
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• 제4권2호
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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.

• 대한가정학회지
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• 제41권5호
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• pp.109-118
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• 2003

The purpose of this study was to analyze the utilization of Database Information System of Fashion Brands in Daegu area. The interviews, reviews of previous studies and the empirical investigations were processed for this study. The questionnaire was administered to 27 fashion brands in Daegu, Korea, from September to October in 2002. Data were analyzed by using frequency, mean and percentage utilizing SPSS statistical package. There were no brand differentiation in brand characteristics, items, target age and company size in Daegu Fashion brands. Awareness of Information Network and Usages of Internet marketing were in relatively low level. The rate of the brands possessing Web-site, POS system and Customer ID card were less than one third. More than a half of the brands had Customer Database system.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.766-769
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• 2000

In recent years, Internet/Intranet represents the next generation of computing environment. Therefore, it is necessary to integrate WWW((World Wide Web) over internet/intranet and DBMS(Database Management System) in proportion to the increase of various users' request and an amount of data variety. Also, also full variety of service over WWW need to accomplish rapidly modification of bug and make a betterment of system according to a feature of rapid change of information and an importance of interaction with users. The typical CGI method commonly used to connect with database has a disadvantage in time and resources in system due to frequent connection with database. Therefore, this paper provides the conceptual structure and implementation of information management system over WWW with applying a recent information technology called ASP(Active Server Pages) that controls and arranges client logic dynamically in server-side and introducing a concept of working group and folder to database design.

• 항공우주시스템공학회지
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• 제2권4호
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• pp.13-18
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• 2008

Airworthiness is a term used to dictate whether an aircraft is worthy of safe flight. It is illegal in most countries to fly an aircraft without first obtaining an airworthiness certificate from the responsible government agency. For developing an aircraft, the design modifications and upgrades are considered a high financial risk proposal for most Program Managers(PMs). However Design-to-Certification Integrated System can be a great help in achieving a good design solution in an acceptable amount of time and flight test. In this paper, we present a method to construct database for the Development of Design-to-Certification Integrated System. By using this database, the human designer could manage and find the regulation and requirements related with his concern effectively.

• Journal of the Korean Data and Information Science Society
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• 제18권1호
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• pp.161-174
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• 2007

In this paper, we propose a high performance database cluster system called HyperDB to process OLAP queries efficiently. HyperDB is a virtual database system running on top of internet-connected PCs; the PCs are used for their own purpose at ordinary times, but they are able to participate in the database cluster system at non-office hours. We propose fully logical replication technique and optimal parallel intra-query routing technique for extensibility and performance. Experiment for TPC-R benchmark shows significant performance upgrade compared with conventional approaches.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.172-175
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• 1992

This paper proposes the methods to construct the tree-structured database and analyze the distribution system network. In order to cope with an extensive amount of data and the frequent breaker switching operations in distribution systems, the database for system configuration is constructed using binary trees. Once the tree-structured database has been built, the system tracing of distribution network can be rapidly performed. This remarkably enhances the efficiency of data search and easily adapts to system changes due to switching operations. The computation method of fast power flow using tree search strategies is presented. The methods in the paper may be available in the field of distribution system operation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.398-401
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• 2008

With the advance of internet and computer processing technique, users can easily access and use the multimedia contents involving the various pictures, videos and audios information. And users request more convenient and accurate multimedia services. In these environments, it is difficulties to integrate and manage metadata standards because there are various standards in multimedia applications according to types of services and data formats individually. In this paper, we design and implement the multimedia metadata management system for integrating from heterogeneous sources. In our system, we managed heterogeneous metadata by integrating to unified schema using mapping table. Through proposed system, users can search multimedia data easily without considering variety of application services.

• 대한산업공학회지
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• 제28권4호
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• pp.435-442
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• 2002

It is difficult to access and share design data among heterogeneous CAD systems. Usually, different CAD systems exchange the design data using a neutral format such as IGES or STEP. A prototype CAD system which uses a geometric kernel and a commercial database management system has been implemented. The prototype system used the Open Cascade geometric kernel and the commercial object-oriented database ObjectStore. STEP provides the database schema. The database can be accessed from commercial CAD systems such as SolidWorks or Unigraphics. The data access module from a commercial CAD system is developed with the CAD system's native API, ObjectStore API functions, and ActiveX.

• 산업공학
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• 제9권3호
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• pp.257-268
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• 1996

This paper illustrates the process of developing and configuring the prototype Computer Analysis System for Controlling Occupational WORKload (CAS-COWORK). The software interface between the database and expert system was attempted. The database is used for storing and retrieving series of data entered by general users and the expert system is used for identifying and solving occupational problem areas. Two theories were applied in developing the algorithm base of CAS-COWORK that were used to calculate overall workload stress level. The fuzzy set theory was introduced to capture the subject‘s workload stress perception. The Analytic Hierarchy Process (AHP) was introduced to estimate the importance of the task and workplace variables. The purpose of the system development is for future prediction and problem solving which would be highly valuable to the industrial engineer.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.605-611
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• 2005

System safety management to secure complicated system safety such as railway and nuclear includes various factors. Those are prevention of accidents, faults management, human factor, men-machine relation, organization factor, safety culture, quality/quantity safety performance goal, and safety regulations. To manage them, it is required that database which is based on most analysis is established. Therefore system safety could be controlled. This research defines data required to safety management, and that is aimed at deriving plans in order to establish them as database. To accomplish that, safety information management of other systems such as aviation and marine is reviewed. Also, the present conditions of available data in the filed of domestic railway are analysed, and then it provides plans for. establishing database to build up advanced railway system safety information management systems.