• Journal of KIISE:Databases
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• v.32 no.6
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• pp.641-649
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• 2005

As XML is widely used with the development of internet, many researches on the XML storage and query processing have been done Several index techniques have been proposed to efficiently process XML path queries. Recently, structural join has received murk attention as a method to protest the path query. Structural join technique process a path query by identifying the containment relationship of elements. Especially, it has an advantage that we can get the result set by simply comparing related elements only instead of scanning whole document. However during the comparison process, unnecessary elements that are not included in the result set can be scanned. So we propose a new technique, the level structural join. In this technique, we use both the relationship and the level distribution of elements in the path query. Using this technique, we tao improve the performance of query processing only by comparing elements with specific level in the target inverted level.

• Journal of KIISE:Databases
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• v.35 no.1
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• pp.1-16
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• 2008

Join queries having heavy cost are necessary to Data Stream Management System in Sensor Network where plural short information is generated. It is reasonable that each join operator has a sliding-window constraint for preventing DISK I/O because the data stream represents the infinite size of data. In addition, the join operator should be able to take multiple inputs for overall results. It is possible for the MJoin operator with sliding-windows to do so. In this paper, we consider the data stream environment where multiple MJoin operators are registered and propose MMJoin which deals with issues of building and processing a globally shared query considering characteristics of the MJoin operator with sliding-windows. First, we propose a solution of building the global shared query execution plan. Second, we solved the problems of updating a window size and routing for a join result. Our study can be utilized as a fundamental research for an optimization technique for multiple continuous joins in the data stream environment.

• Journal of KIISE:Databases
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• v.33 no.2
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• pp.224-238
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• 2006

As XML became the standard of data exchange in the internet, the needs for effective query processing for XML data in streaming environment is increasing. Applying the existing database technique which processes data with the unit of tuple to the streaming XML data causes the out-of-memory problem due to limited memory volume. Likewise the cost for searching query path and accessing specific data may be remarkably increased because of special structure of XML. In a word it is unreasonable to apply the existing database system to the streaming environment that processes query for partial data, not the whole one. Thus, it should be able to search partial streaming data that rapidly satisfies join predicate through using low-capacity memory, based on a store technique suitable to streaming XML data. In this thesis, in order to study the store technique for low-capacity memory, the PCDATA and the CDATA-related parts, which can be used as predicate on join query, were fetched and saved. In addition, in an attempt to compare rapid join predicates, the range window of streaming XML data was set with the object of selectively joining windows that satisfies the query, based on Cardinality * and + among the structure information of DTD.

• The Journal of Information Technology and Database
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• v.3 no.2
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• pp.3-24
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• 1996

In this paper a data replicator scheme with a distributed join architecture is suggested with its cost functions and the performance results. The contribution of this scheme is not only minimizing the number of base relation locks in distributed database tables but also reducing the remote transmission amount remarkably, which will be able to embellish the distributed databse system practical. The differential files that are derived from the active log of the DBMS are mainly forcing the scheme to reduce the number of base relation locks. The amount of transportation between relevant sites could be curtailed by the tuple reduction procedures. Then we prescribe an algorithm of data replicator with its cost function and show the performance results compared with the semi-join scheme in their distributed environments.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.238-246
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• 2000

The distance join has been introduced previously, which finds nearest pairs in the order of distance incrementally among two spatial data sets built with multidimensional indexes like R-trees. We propose efficient K-distance joins when the number(K) of pairs to find is preset. Especially, we develop a distance join algorithm with bi-directional expansion and optimized plane sweeping using selection method of sweep axis and direction. The experiments on real spatial data sets show that the proposed algorithm is much better than the former algorithms.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2536-2542
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• 2000

The dominator tree presents the dominance frontier from directed graph to the tree. we present the effective algorithm for constructing the dominator tree from arbitrarY directed graph. The reducible flow graph was reduced to dominator tree after dominator calculation. And the irreducible flow graph was constructed to dominator-join graph using join-edge information of information table. For reducing the dominator tree from dominator-join graph, we present the effective sequency reducible algorithm and delay reducible algorithm.

• Asia pacific journal of information systems
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• v.2 no.1
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• pp.57-76
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• 1992

Material Requirement Planning(MRP) has been the most widely implemented large scale production management system in the manufacturing industry. Computerization of MRP systems involves, in general, Bill Of Material(BOM) explosion algolithms which usually takes heavy computation time. In order to improve the effectiveness of the MRP systems, we propose to build a logical BOM database in advance, which reflects the Join operations for the BOM explosion. It reduces the response time for the BOM indented explosion. It reduces the MRP processing time. It also increased main memory utilization.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.569-578
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• 2003

In the present steady the flow characteristics of turbulent steady flows were experimentally investigated in the exit region of join stream. The experimental was carry out to measure the velocity profiles of air in a square duct. For the measurement of velocity profiles, a hot-wire anemometer was used. The experimental results shows that the velocity profiles do not change behind the fully developed flow region , which is defined as dimensionless axial direction x/Dh=50. In addition, the gradient of shear stress distribution became stable as the flow reached progress downstream.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.581-584
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• 2001

신경망이 만들어내는 출력에 대한 정보는 수치적으로 분산되어 신경망에 저장되므로, 인간이 직접 해석하기가 힘들다. 본 논문에서는 LRE(link rule extraction)기법인 NofM 알고리즘의 6단계 중에서 초기 단계인 가중치 군집화 단계를 개선하여 추출되는 규칙들의 전제부에 들어가는 규칙 조건들의 수를 조절함으로써, 추출된 규칙이 입력 특성에 대한 정보를 과잉 일반화하거나, 과잉 구체화하는 것을 피할 수 있음을 실험을 통해 보였다. 일반적으로 NofM 알고리즘에서 가중치들을 군집화한 때는 Join 알고리즘을 사용하는데, 본 논문에서는 Join 알고리즘의 Join condition을 0.05부터 0.25까지 0.05씩 점진적으로 확대하여 클러스터링을 하여줌으로써 신경망의 출력에 중요한 역할을 하는 가중치들을 효과적으로 군집화함을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.226-231
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• 2007

최근 비즈니스 프로세스가 복잡해짐에 따라, 비즈니스 프로세스를 설계 한 후 실행하는 과정에서 예상치 못한 문제들이 발생할 가능성 또한 높아지고 있다. 예상치 못한 문제의 발생은 막대한 비용 및 인적자원의 손실을 초래하기 때문에, 설계 된 비즈니스 프로세스는 엔진에 의해 실행되기 전에 다양한 방법으로 검증을 받아야 한다. 본 논문은, BPMN으로 설계된 비즈니스 프로세스의 컨트롤 플로우(Control Flow)에 대한 이상현상 중 데드락과 동기화의 부족에 대한 검증을 목적으로 한다. 데드락과 동기화의 부족은 Split 게이트웨이와 Join 게이트웨이의 종류에 따른 의미적 차이에 의해 발생한다. 본 논문에서는 비즈니스 프로세스를 방향성 그래프로 변환함으로써 Split 게이트웨이와 쌍을 이루는 Join 게이트웨이를 찾을 것을 제안하며, 찾아낸 (Split,Join)쌍은 컨트롤 플로우 검증 테이블을 이용하여 이상현상을 검증한다.