• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.119-124
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• 2007

인터넷 웹사이트의 급격한 증가와 함께 이용자도 증가하고 있으며, 이용 목적은 주로 자료검색과 조회서비스 이다. 조회 요청이 많을수록 질의의 증가를 야기하며, 데이터베이스 서버의 질의 분석(Parse), 질의 실행 계획(Query Execution Plan)을 과도하게 발생시킨다. 즉 데이터베이스 서버에서 처리하는 작업량의 과부하로 인하여 병목현상을 초래한다. 데이터베이스 서버의 조회를 위한 질의처리량을 감소시키는 작업이 필요하다. 그리고 조회 대상이 데이터는 웹사이트에서 자주 갱신되지 않거나, 데이터가 주기적으로 갱신되는 특징이 있다. 이 데이터를 대상으로 데이터베이스 캐쉬 엔진을 구성하면 데이터베이스 서버의 과부하률 해소 할 수 있다. 본 논문에서는 유사 질의 매칭 기반 데이터베이스 캐친 엔진을 설계하고 구현한다. 유사 질의 매칭 기반으로 하여 적중률을 높여 데이터베이스 병목현상을 해결하여, 검색서비스에 더욱 효과적일 것으로 사료되며, 웹사이트의 성능 향상을 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1693-1713
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• 2018

An important technique used by database administrators (DBAs) is to improve performance in decision-support workloads associated with a Star schema is multi-level partitioning. Queries will then benefit from performance improvements via partition elimination, due to constraints on queries expressed on the dimension tables. As the task of multi-level partitioning can be overwhelming for a DBA we are proposing a wizard that facilitates the task by calculating a partitioning scheme for a particular workload. The system resides completely on a client and interacts with the costing estimation subsystem of the query optimizer via an API over the network, thereby eliminating any need to make changes to the optimizer. In addition, since only cost estimates are needed the wizard overhead is very low. By using a greedy algorithm for search space enumeration over the query predicates in the workload the wizard is efficient with worst-case polynomial complexity. The technology proposed can be applied to any clustering or partitioning scheme in any database management system that provides an interface to the query optimizer. Applied to the Teradata database the technology provides recommendations that outperform a human expert's solution as measured by the total execution time of the workload. We also demonstrate the scalability of our approach when the fact table (and workload) size increases.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.2
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• pp.85-90
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• 2017

Various mobile devices are spreading in recent developments in mobile computing environments. Especially the popularity of mobile devices equipped with GPS has become widespread, and various application services utilizing location information are born. In this paper, we propose a system model for storing and managing the trajectory of moving objects, which is the set of location information of moving objects acquired in continuous time, and the UDF (User-Defined Functions) based trajectory index method which can quickly query the large data set of moving object and the Pre-Materialized table method. Then we compare and evaluate the performance of each method through experiments. Experimental results show that the Pre-Materialized table method is about 1.2 times faster than the UDF based trajectory index method on execution time.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.48-54
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• 2008

This paper analyzes cost tradeoffs between memory usage and computation for window-based operators in data stream environments. It identifies generic operator network constructs, and sets up a cost model for the estimation of the expected memory reduction and the computation overheads when window memory relocations are applied to each operator network construct. This cost model helps to identify the utility of window memory relocations. It also helps to apply window memory relocation to improve a query execution plan to save memory usage. The proposed approach contributes to expand the scope of query processing and optimization in data stream environments. It also provides a basis to develop a cost estimation model for the query optimization using window memory relocations.

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.125-134
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• 2009

A biological data acquisition based on web has emerged as a powerful tool for allowing scientists to interactively view entries form different databases, and to navigate from one database to another molecular-biology database links. In this paper, the biological conceptual model is constructed hybrid biological data model to represent interesting entities in the data sources to applying navigation rule property for each biological data source based on four biological data integrating layers to control biological data. When some user's requests for application service are occurred, we can get the data from database and data source via web service. In this paper, we propose a query processing model and execution structure based on integrating data layers that can search information on biological data sources.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.95-103
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• 2011

The actual utilization of Semantic Web technology which aims to provide more intelligent and automated service for information retrieval over the Web becomes gradually reality. RDF is widely used as the one of standard formats to present and manage the voluminous data on the Web. Efficient query processing on RDF data, therefore, is one of the ongoing research topics. Retrieving resources having a specific association from a given resource is the typical query processing type and several researches for this have done. However the most of previous researches have not fully considered discovering the complex relationship among resources such as returning the association between resources as the query processing result. This paper introduces the indexing and query processing for ${\rho}$-intersect operation which is one of the semantic association retrieval types. It includes an indexing scheme using suffix array and optimal processing approaches for handling ${\rho}$-intersect operation. The experimental evaluations shows that the average execution times for the proposed approach is 3~7 times faster than the previous approach.

• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1557-1564
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• 1997

We propose an extension to Prolog called the count term for controlling Prolog execution. The purpose is to allow the programmers as well as the users to have greater flexibility in controlling the execution behavior of Prolog programs and for limiting the number of answers or proofs retrieved when Prolog is used as a database query language. Both syntax and operational semantics of the count term are defined. An implementation strategy based on WAM (Warren Abstract Machine) by modifying instructions related to backtracking behavior has been suggested.

• Journal of Information Technology Services
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• v.5 no.2
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• pp.107-123
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• 2006

The objectives of this study is to develop a strategy for the adoption of BPM(Business Process Management) standards and an implementation guideline of the BPM standard for BPM solution developers focusing on BPEL(Business Process Execution Language) which is regarded as the most important BPM standard. In the heterogeneous and distributed IT environments, every type of enterprise software requires standards to enhance interoperability. BPMS(Business Process Management System), which is a type of enterprise software requires BPM standards such as BPEL(Business Process Execution Language), BPMN(Business Process Modeling and Notation), BPQL(Business Process Query Language) and so on to achieve multi-system interoperability and component interoperability with their BPM solutions. It is quite helpful to provide the adoption strategy concerning BPM standards for each type of BPM solution vendors who need the BPM standards. Since the BPEL is conceived as the most important BPM standard and widely adopted by many BPM vendors, we have proposed a reference architecture for BPEL implementation and also developed the detail implementation guideline of core components of the BPM system supporting the BPEL standard. Using the strategy and implementation guideline proposed in this work, BPM solution vendors can establish their own standard adoption strategy and they can also develop their BPM solutions supporting the BPM standards more efficiently.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.637-649
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• 2001

ㆍ Research Method - Experimental Design ㆍWhen Entity Bean is deployed and Client request to inquire a specific information of Doctor Table, we experiment Total Time for Query Execution according to Time Measurement Operation in Client code. ㆍWe can apply the statistics for the experiment to the design of Entity Beans.(omitted)

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.25-30
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• 1992

A knowledge based hybrid simulation environment has been established which supports the simulation procedure from the modeling step to the experimentation step by providing various tools, query, and advisory. The knowledge base in the established environment uses the If-Then Rule to transfer the fact input from the user to the act for the execution of the simulation process. Simulation non-experts are the user target and non-specific area is the application target.