• Journal of Korea Spatial Information System Society
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• v.11 no.3
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• pp.9-18
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• 2009

Recently, due to the advanced technologies of mobile devices and wireless communication, there are many studies on telematics and LBS(location-based service) applications. because moving objects usually move on spatial networks, their locations are updated frequently, leading to the degradation of retrieval performance. To manage the frequent updates of moving objects' locations in an efficient way, a new distributed grid scheme, called DS-GRID (distributed S-GRID), and k-NN(k-nearest neighbor) query processing algorithm was proposed[1]. However, the result of k-NN query processing technique may be invalidated as the location of query and moving objects are changed. Therefore, it is necessary to study on continuous k-NN query processing algorithm. In this paper, we propose both MCE-CKNN and MBP(Monitoring in Border Point)-CKNN algorithmss are S-GRID. The MCE-CKNN algorithm splits a query route into sub-routes based on cell and seproves retrieval performance by processing query in parallel way by. In addition, the MBP-CKNN algorithm stores POIs from the border points of each grid cells and seproves retrieval performance by decreasing the number of accesses to the adjacent cells. Finally, it is shown from the performance analysis that our CKNN algorithms achieves 15-53% better retrieval performance than the Kolahdouzan's algorithm.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.98-105
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• 2009

In this paper, new data centric storage that is dynamically adapted to the change of work load is proposed. The proposed data centric storage distributes the load of hot spot area by using multilevel grid technique. Also, the proposed method is able to use existing routing protocol such as GPSR (Greedy Perimeter Stateless Routing) with small changes. Through simulation the proposed method enhances the lifetime of sensor networks over one of the state-of-the-art data centric storages. We implement the proposed method based on a operating system for sensor networks, and evaluate the performance through running based on a simulation tool.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1013-1024
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• 2022

In addition to the assessment measure of electric quality levels, load loss are also a factor in hindering the financial profits of electrical sales companies. Therefore, accurate analysis of load losses generated from distributed power networks is very important. The accurate calculation of load losses in the distribution line has been carried out for a long time in many research institutes as well as power utilities around the world. But it is increasingly difficult to calculate the exact amount of loss due to the increase in the congestion of distribution power network due to the linkage of distributed energy resources(DER). In this paper, we develop smart grid big data infrastructure in order to accurately analyze the load loss of the distribution power network due to the connection of DERs. Through the preprocess of data selected from the smart grid big data, we develop a load loss analysis model that eliminated 'veracity' which is one of the characteristics of smart grid big data. Our analysis results can be used for facility investment plans or network operation plans to maintain stable supply reliability and power quality.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.283-290
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• 2016

As the development of recent science and technology, high-performance computing resources is needed to solve complex problems. To reach these requirements, it has been actively studied about grid computing that consist of a huge system which bind a heterogeneous high performance computing resources into on which are geographically dispersed. However, The current research situation which are the process to obtain the best results in the limited resources and the scheduling policy to accurately predict the total execution time of the real-time task are very poor. In this paper, in order to overcome these problems, we suggested a grid computing-based risk management system which derived from the system structure and the process for improving the efficiency of the system, grid computing-based working methodology, risk policy module which can manage efficiently the problem of the work of resources(Agent), scheduling technique and allocation method which can re-allocate the resource allocation and the resources in problem, and monitoring which can manage resources(Agent).

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.49-51
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• 2005

그리드 시스템은 기존의 클러스터링과는 달리 지역적으로 분산되어 있는 컴퓨팅 자원을 네트워크로 상호 연동하여 사용하는 시스템이다. 그러므로 사용할 자원의 조합의 선택에 따라 그리드 컴퓨팅 성능은 큰 영향을 받는다. 그러나 현재 대표적인 Grid Middleware Toolkit인 Globus에서는 자원 선택에 관련해서는 별다른 방안을 제시하고 있지 않다. 이와 관련하여 본 논문에서는asymmetric MPI application에 대해 효율적인 자원을 선택하기 위한 적절한 cluster조합의 선택기법을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.37-39
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• 2004

그리드 컴퓨팅에서 가상조직은 분산되어 있는 여러 자원들과 사용자들로 구성된다. 가상조직을 구성하는 일은 그리드 컴퓨팅에서 중요한 일이다. 가상조직은 목적에 따라 동적으로 구성되며 목적을 완성하고 사라진다 기존의 가상조직을 위한 권한 위임 구조들은 하나의 가상조직 환경에 중점을 두며 동적인 가상조직 환경을 고려하지 못하고 있다. 또한 자원 제공자, 가상조직 관리자, 그리고 사용자 모두를 위한 상세한 권한 위임 기법을 제공하지 않는다. 이 논문에서 우리는 동적인 가상조직에서 티켓을 이용한 상세한 권한 위임 서비스인 TAS 아키텍처를 제안한다. 기존의 아키텍처와 다르게 TAS 아키텍처는 티켓을 사용하여 여러 가상조직들을 위한 상세한 권한 위임 서비스를 제공한다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.12-18
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• 1999

3차원 FDTD법을 이용하여 GPR 안테나의 복사 특성을 해석하였다. Bow-tie 안테나 구조에 대해서는 삼각형 countour-path FDTD, 지하와 같은 분산매질에 대한 흡수경계조건으로 dispersive PML, 공기와 지하간에는 다층구조에 대한 최적 PML 부가조건을 적용하여 Bourgeois의 FDTD계산 모형을 개선하였다. 또한 확장 그리드 기법을 적용하여 수치 계산에 필요한 셀 수를 줄일 수 있음을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.40-41
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• 2010

• Journal of KIISE
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• v.42 no.11
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• pp.1303-1313
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• 2015

MapReduce provides high levels of system scalability and fault tolerance for large-size data processing. A MapReduce-based k-nearest-neighbor(k-NN) join algorithm seeks to produce the k nearest-neighbors of each point of a dataset from another dataset. The algorithm has been considered important in bigdata analysis. However, the existing k-NN join query-processing algorithm suffers from a high index-construction cost that makes it unsuitable for the processing of bigdata. To solve the corresponding problems, we propose a new grid-based, k-NN join query-processing algorithm. Our algorithm retrieves only the neighboring data from a query cell and sends them to each MapReduce task, making it possible to improve the overhead data transmission and computation. Our performance analysis shows that our algorithm outperforms the existing scheme by up to seven-fold in terms of the query-processing time, while also achieving high extent of query-result accuracy.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.81-87
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• 2010

This paper proposes a G-BLAST(BLAST using Grid Computing) system, an integrated software package for BLAST searches operated in heterogeneous distributed environment. G-BLAST employed 'database splicing' method to improve the performance of BLAST searches using exists computing resources. G-BLAST is a basic local alignment search tool of DNA Sequence using grid computing in heterogeneous distributed environment. The G-BLAST improved the existing BLAST search performance in gene sequence analysis. Also G-BLAST implemented the pipeline and data management method for users to easily manage and analyze the BLAST search results. The proposed G-BLAST system has been confirmed the speed and efficiency of BLAST search performance in heterogeneous distributed computing.