• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10a
• /
• pp.547-551
• /
• 2006

디렉터리와 파일의 계층적 구조를 가지는 계층적 파일 시스템은 오늘날 대부분의 범용 컴퓨터에서 흔히 사용되고 있다. 계층적 파일 시스템은 직관적이고, 체계적이며, 단순하다는 장점이 있으나 검색이 용이 하지 않으며, 메타데이터를 관리하기 어렵다는 단점이 존재한다. 본 연구에서는 계층적 파일 시스템의 장점과 빠른 검색기능을 활용하여 메타데이터를 검색하고 관리할 수 있는 데이터베이스의 장점을 결합하여 계층적 파일 시스템에서 메타데이터를 관리할 수 있는 방법을 제안하였다. 데이터 그리드와 같이 분산된 데이터 저장 장치를 연동하여야 하는 경우에 원격지에 있는 파일 시스템의 파일들을 검색하는 일이 빈번히 수행되는데, 이 경우 본 연구에서 제안한 방법을 사용하면 효과적인 시스템을 기대할 수 있다.

• Proceedings of the Korea Contents Association Conference
• /
• 2007.11a
• /
• pp.555-559
• /
• 2007

AMGA is a metadata catalogue service which offers access to metadata for files stored on the Grid. We evaluated the performance of AMGA and analyzed overhead in the current AMGA implementation. It had 700% poor throughput (read/insert per second) compared with the direct DB access. The biggest overhead was in managing GSI/SSL Connections, degrading throughput about 350%. We alsomeasured the throughput of load-balanced AMGA services, and it showed linear throughput improvement when we increased the number of AMGA server. In addition, we measured the throughputin the WAN environment, and it showed the number of the maximum connections that an AMGA server can handle is the most critical factor in the throughput.

• Journal of Korea Spatial Information System Society
• /
• v.10 no.1
• /
• pp.29-40
• /
• 2008

With the spread of mobile devices and advances in communication techknowledges, the needs of application which uses the movement patterns of moving objects in history trajectory data of moving objects gets Increasing. Especially, to design public transportation route or road network of the new city, we can use the similar patterns in the trajectories of moving objects that move on the spatial network such as road and railway. In this paper, we propose a spatio-temporal similar trajectory search algorithm for moving objects on road network. For this, we define a spatio-temporal similarity measure based on the real road network distance and propose a grid-based index structure for similar trajectory search. Finally, we analyze the performance of the proposed similar trajectory search algorithm in order to show its efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.6
• /
• pp.1593-1603
• /
• 2016

In the smart grid environment, there are various security threats. In particular, exposure of smart meter data can lead to serious privacy violation. In this paper, we propose a method for de-identification method of metering data. The proposed method is to de-identify the time data and the numeric data, respectively. Therefore, it can't analyze the pattern information from the metering data. In addition, there is an advantage that the query is available, such as the range of search in the database for statistical analysis.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.6
• /
• pp.1266-1272
• /
• 2004

Location-Based Services(LBS) give rise to location-dependent queries of which results depend on the positions of moving objects. Because positions of moving objects change continuously, indexes of moving object must perform update operations frequently for keeping the changed position information. Existing spatial index (Grid File, R-Tree, KDB-tree etc.) proposed as index structure to search static data effectively. There are not suitable for index technique of moving object database that position data is changed continuously. In this paper, I propose a dynamic hashing index that insertion/delete costs are low. The dynamic hashing structure is that apply dynamic hashing techniques to combine a hash and a tree to a spatial index. The results of my extensive experiments show the dynamic hashing index outperforms the $R^$ $R^*$-tree and the fixed grid.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.4
• /
• pp.759-764
• /
• 2021

Because sensitive and private information should be exchanged between electric vehicles and a V2G service provider, reliable communication channel is essential to operate Vehicle-to-Grid (V2G) system which considers battery of electric vehicles as a factor of smart grid. The block chain is a platform for cryptocurrency transaction and fully distributed database system running by only equivalent node in the network without help of any central management or 3^rd party. In this paper, the structure and operation method of the blockchain are investigated, and the application of the blockchain for the V2G system was also explained and analyzed.

• Journal of Korea Spatial Information System Society
• /
• v.11 no.2
• /
• pp.151-161
• /
• 2009

In Location-Based Services (LBSs), users requesting a location-based query send their exact location to a database server and thus the location information of the users can be misused by adversaries. Therefore, a privacy protection method is required for using LBS in a safe way. In this paper, we propose a new cloaking region generation algorithm using grids for privacy protection in LBSs. The proposed algorithm creates a m inimum cloaking region by finding L buildings and then performs K-anonymity to search K users. For this, we make use of not only a grid-based index structure, but also an efficient pruning techniques. Finally, we show from a performance analysis that our cloaking region generation algorithm outperforms the existing algorithm in term of the size of cloaking region.

• The KIPS Transactions:PartD
• /
• v.10D no.4
• /
• pp.567-576
• /
• 2003

Spatial data mining, i.e., discovery of interesting characteristics and patterns that may implicitly exists in spatial databases, is a challenging task due to the huge amounts of spatial data. Clustering algorithms are attractive for the task of class identification in spatial databases. Several methods for spatial clustering have been presented in recent years, but have the following several drawbacks increase costs due to computing distance among objects and process only memory-resident data. In this paper, we propose an efficient grid cell based spatial clustering method for spatial data mining. It focuses on resolving disadvantages of existing clustering algorithms. In details, it aims to reduce cost further for good efficiency on large databases. To do this, we devise a spatial clustering algorithm based on grid ceil structures including cell relationships.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.5
• /
• pp.125-133
• /
• 2016

Data processing capacity and speed are rapidly increasing due to the development of hardware and software in recent time. As a result, data usage is geometrically increasing and the amount of data which computers have to process has already exceeded five-thousand transaction per second. That is, the importance of Big Data is due to its 'real-time' and this makes it possible to analyze all the data in order to obtain accurate data at right time under any circumstances. Moreover, there are many researches about this as construction of smart factory with the application of Big Data is expected to have reduction in development, production, and quality management cost. In this paper, system using In-Memory Data Grid for high speed processing is implemented in semiconductor process which numerous data occur and improved performance is proven with experiments. Implemented system is expected to be possible to apply on not only the semiconductor but also any fields using Big Data and further researches will be made for possible application on other fields.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.2
• /
• pp.1-8
• /
• 2010

In this paper, we propose a scheduling strategy for grid environment that reduces resource cost. This strategy considers resource cost and job failure rate to efficiently allocate local computing resources. The key idea of our strategy is that we use two-level scheduling using remote and local scheduler. The remote scheduler determines the expected total execution times of jobs using the current network and local system status maintained in its resource database and allocates jobs with minimum total execution time to local systems. The local scheduler recalculates the waiting time and execution time of allocated job and uses it to determine whether the job can be processed within the specified deadline. If it cannot finish in time, the job is migrated other local systems, through simulation, we show that it is more effective to reduce the resource cost than the previous Greedy strategy. We also show that the proposed strategy improves the performance compared to previous Greedy strategy.