• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.766-768
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• 2003

Selectivity estimation for spatial query is curial in Spatial Database Management Systems(SDBMS). Many works have been performed to estimate accurate selectivity. Although they deal with some problems such as false-count, multi-count arising from properties of spatial dataset, they can not get such effects in little memory space.* Therefore, we need to compress spatial dataset into little memory. In this paper, we propose a new technique called MW Histogram which is able to compress summary data and get reasonable results. Our method is based on two techniques:(a)MinSkew partitioning algorithm which deal with skewed spatial datasets. efficiently (b) Wavelet transformation which compression effect is proven. We evaluate our method via real datasets. The experimental result shows that the MW Histogram has the ability of providing estimates with low relative error and retaining the similar estimates even if memory space is small.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.631-634
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• 2014

When to build a Web and Cloud Computing environment, it is essential to used a database system. Database systems includes commercial programs, such as Oracle and MS-SQL, but also similar to the performance of commercial applications, there are many free programs. In particular, PostgreSQL, MySQL, MariaDB are no costs, but the source is open to the public can be applied to a variety of environments. This paper presents an open source relational database management system, the trends are examined.

• Spatial Information Research
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• v.1 no.1
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• pp.7-16
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• 1993

Current computer technologies developing. our requirements are changing from simple alpha-numeric processing to graphic and image. spatial data processing which are easy for user to understand and use. Geographic information system is a kind of spatial database system that can not only print out the data in the form of maps but also manipulate. store. retrieve. and analyze the geographic data. It is efficient system that can process the spatial data which has a geographical feature and its relative attribute data. Conventional relational database management systems are not suitable for spatial data processing, so we need to design the spatial database mana-gement system which is suitable for efficient spatial data processing. In this paper we design the extended storage management system that supports the spatial index technique that allows user to access fast and store and manage the enormous spatial data efficiently like geographic information system.

• Asia pacific journal of information systems
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• v.4 no.1
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• pp.115-138
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• 1994

Current database systems are based on the assumption that a datum denotes the same meaning; however, in reality, the violation of this assumption is not unusual. Some data are created in such a way that they represent different sets of attribute values. The current research formulates this phenomenon as dissimilarities of derivation rules and defines multi-derived data as ones that are derived by multiple rules. For multi- derived data, this research proposes a new retrieval scheme and analyze its implication with relation to data retrieval.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1188-1190
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• 2003

Taipei Watershed Management Bureau (WRATB) is a government agency entitled for water resources protection at two major watersheds in order to provide drinking water for about four millions population in Taipei on a sustainable basis. At WRATB, there are two major public sewage treatment facilities which can convert sewage in each watershed into an acceptable state before they were discharged into rivers. More than 82% of household wastewater have been collected and treated by the two public sewage systems. However, households at remote area still need more effective sewage management prescriptions. The objective of this paper is to implement geographic information systems in order to provide more effective approaches that sewage management can be easier and cost effective. ArcIMS was implemented for Internet browsing and map server of those sewage facilities on personal computers, laptop computers. In the open field, ArcPAD was implemented with personal digital assistant (PDA) such that compact flash type's global positioning systems (GPS) and digital camera can be utilized with PDA. All sewage facilities digital files were convert into ArcMap format files. MapObjects and visual BASIC were used to create sewage application modules to meet every single technician personal flavor. ASP.NET was implemented for Internet database manipulations of all sewage databases. Mobile GIS was the key component of GIS applications in the open field for sewage management on a basis of house by house. Houses at remote area, which can not cover by the two public sewage systems, were managed by PDA and laptop computers with GPS and digital camera. Sewage management at Taipei Watershed Management Bureau is easier both in the open field and in the office. Integration of GPS, GIS, and PDA makes sewage management in the open field much easier. ArcIMS, MapObjects, ASP.NET and visual BASIC make sewage management can be done in the office and over Internet.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.157-170
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• 1999

The web-based groupware systems hold many possibilities for system developers and users. Especially, web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. However, current web technologies have limitations in supporting this, largely because the existing Hypertext Transfer Protocol(HTTP) is unidirectional and does not allow web servers to send messages to their web browsers without first receiving requests from them. This paper proposes an active web server that can overcome such limitations and facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such goals, the active web server manages dependency relationships beween shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefulness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System(0DBMS) called OBJECTSTERE using the C++ programming language.

• Management & Information Systems Review
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• v.1
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• pp.229-268
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• 1997

Recently, object-oriented concepts and technology are on the leading edge of programming language and database systems research, and their usefulness in those contexts has been successfully demonstrated. The adoption of object-oriented concept to the design of model bases has several benefits. From the perspectives of object-oriented approach, models in a model base are viewed as object which encapsulate their states and behaviors. This paper focuses on the design of an object-oriented model base that handles various resources of DSS(data, knowledge, models, solvers) in a unified fashion. For the design of a model base, we adopted Object Modeling Techniques(OMT). An object model of OMT can be used for the conceptual design of an overall model base schema. The object model of OMT provides several advantages over the conventional approaches in model base design. The main advantage are model reuse, hierarchical model construction, model sharing, meta-modeling, and unified model object management.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.521-530
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• 2005

Many researches are going on with regard to issues and problems related to mobile database systems, which are caused by the weak connectivity of wireless networks, the mobility and the Portability of mobile clients. Mobile computing satisfies user's demands for convenience and Performance to use information at any time and in any Place, but it has many Problems to be solved in the aspect of data management. The purpose of our study is to design Mobile Query Processing System(MQPS) to solve problems related to database hoarding, the maintenance of shared data consistency and the optimization of logging, which are caused by the weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client-server environments. In addition, we proved the superiority of the proposed MQPS by comparing its performance to the C-I-S(Client-Intercept- Server) model.

• 한국디지털정책학회:학술대회논문집
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• 2004.11a
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• pp.221-229
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• 2004

This paper aims at developing communication module and application prcgram for client management module and developing database management module and managing wireless communication facilities for server systems. To construct these aims, we have adapted DES algorithm and researched on encrypting and decrypting module development applicable to SMS Security System and optimize module size and processing speed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.219-222
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• 2000

Systematic management of data related to business process, and information exchange within existing information systems or between different companies have recently become an important issue. This paper tries to solve such problems by using form based workflow system using XML(extensible Markup Language), a standard for digital document exchange. In this system, a new model that formalizes documents into XML form documents and manages them is developed. By defining and operating form documents by XML, information exchange within existing information systems such as ERP and SCM or between different companies, and interoperability between different WFMS can be easily achieved. In addition, by matching form, a formalized document, with existing database schema, WFMS can be directly applied to existing information system, thus enabling continuity of data management and business activity.