• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2574-2586
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• 1999

Since a SGML document is composed of elements, the primitive unit of information, SGML information retrieval should support retrieval on element as well as document. In addition, SGML index organization should support the partial insertion and deletion of document for the dynamic environment. For this, we propose a SGML index organization suited to structured-based retrieval for dynamic environment. Based on the proposed index organization, we design a SGML index manager to support content-based and structure-based retrieval efficiently. We implement the SGML index manager based on O2 storage system and compare the performance of our SGML index manager with the conventional SGML index manager. According to the performance comparison, it is shown that the proposed index structure achieves better retrieval performance than the conventional K-ary complete tree.

• International Journal of Contents
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• v.3 no.3
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• pp.1-5
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• 2007

The main memory DBMS (MMDBMS) efficiently supports various database applications that require high performance since it employs main memory rather than disk as a primary storage. An index manager is an essential sub-component of a DBMS used to speed up the retrieval of objects from a large volume of a database in response to a certain search condition. Previous research efforts on indexing proposed various index structures. However, they hardly dealt with the practical issues occurred in implementing an index manager on a target DBMS. In this paper, we touch these issues and present our experiences in developing the index manager. The main issues are (1) compact representation of an index entry, (2) support of variable-length keys. (3) support of multiple-attribute keys, and (4) support of duplicated keys.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.11-22
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• 2004

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per you. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules： the interface manager provides the interface for PDA users； the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques； the query manager processes spatial and non-spatial query : the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index : the GIS server interface provides the interface with disk-based GIS. The MR-tree proposed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimensional MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memory techniques, the memory data manager uses page tables for spatial data, non- spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.605-619
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• 2010

Caching of frequently accessed data in multi-hop ad hoc environment is a technique that can improve data access performance and availability. Cooperative caching, which allows sharing and coordination of cached data among several clients, can further en-hance the potential of caching techniques. In this paper, we propose a fuzzy cooperative caching scheme in mobile ad hoc networks. The cache management of the proposed caching scheme not only uses adaptively CacheData or CachePath based on data sim-ilarity and data utility, but also uses the replacement manager based on data pro t. Also, the proposed caching scheme uses a prefetch manager. When the TTL of the cached data expires, the prefetch manager evaluates the popularity index of the data. If the popularity index is larger than a threshold, the data is prefetched. Otherwise, its space is released. The performance of the proposed scheme is evaluated analytically and is compared to that of other cooperative caching schemes.

• The Journal of Information Technology and Database
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• v.7 no.1
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• pp.27-39
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• 2000

In this paper, we design and implement a XML management system based on OODBMS that supports structured information retrieval of XML documents. We also propose an object oriented modeling to store and fetch XML documents, to manage image data, and to support versioning for the XML document management system(XMS). The XMS consists of a repository manager that maintains the interfaces for external application programs, a XML instance storage manager that stores XML documents in the database, a XML instance manager that fetches XML documents stored in the database, a XML index manager that creates index for the structure information and the contents of documents, and a query processor that processes various queries.

• Journal of Information Technology Services
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• v.7 no.1
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• pp.117-130
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• 2008

Multi-attribute risk assessments provide a useful framework for systematic quantitative risk assessment that the security manager can use to prioritize security requirements and threats. In the first step, the security managers identify the four significant outcome attributes(lost revenue, lost productivity, lost customer, and recovery cost). Next. the security manager estimates the frequency and severity(three points estimates for outcome attribute values) for each threat and rank the outcome attributes according to AHP(Analytic Hierarchy Process). Finally, we generate the threat index by using muiti-attribute function and make sensitivity analysis with simulation package(Crystal Ball). In this paper, we show how multi-attribute risk analysis techniques from the field of security risk management can be used by security managers to prioritize their organization's threats and their security requirements, eventually they can derive threat index. This threat index can help security managers to decide whether their security investment is consistent with the expected risks. In addition, sensitivity analysis allows the security manager to explore the estimates to understand how they affect the selection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.661-674
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• 2000

The main memory DBMS(MMDBMS) efficiently supports various database applications that require high performance since it employs main memory rather than disk as a primary storage. In this paper, we discuss theexperiences obtained in developing the index manager of the Tachyon, a next-generation MMDBMS. The indexmanager is an essential sub-component of the DBMS used to speed up the retrieval of objects from a largevolume of a database in response to a certain search condition. Previous research efforts on indexing proposed various index structures. However, they hardly dealt with the practical issues occured in implementating an index manager on a target DBMS. In this paper, we touch these issues and present our experiences in developing the index manager on the Tachyon as solutions. The main issues touched are (1) compact representation of an indexentry, (2) support of variable-length keys, (3) support of multiple-attribute keys, (4) support of duplicated keys,(5) definition of external APls, (6) concurrency control, and (7) backup and recovery. We believe that ourcontribution would help MMDBMS developers highly reduce their trial-and-errors.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.137-149
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• 1995

A spatial index is necessary to support an efficient search in a geographical information system (GIS) that is important in these days. In this paper, we design and implement a geographical data manager, called GOOD (Geo-object Oriented Data Manager) 2.0, by extending GOOD 1.0 with a spatial index processing module. That is, R-tree and R*-tree are used as a spatial index in this paper to make an efficient search possible. In addition, this paper conducts a performance evaluation to measure the improvement in search efficiency and analyzes the results of the performance evaluation. When the performance evaluation is carried out, we consider various environment factors to allow an GIS administrator to use the results as a basic data in selecting an appropriate spatial index.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1033-1043
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• 2000

Recently as the user request on NoD (News-on-Demand) is largely increasing, there are a lot of researches to fulfill it. However, because of short life-cycle of new video data and periodical change of video data depending on anchor, it is difficult to apply the conventional video storage techniques to NOD applications directly. For this, we design and implement low-level storage manager for efficient storage and retrieval of multimedia data in NOD Services. Our low-level storage manager not only efficiently sotres video stream dat of new video itself, but also handles its index information. It provides an inverted file method for efficient text-based retrieval and an X-tree index structure for high-dimensional feature vectors. In addition, our low-level storage manager provides some application program interfaces (APIs) for storing video objects itself and index information extracted from hierarchial new video and some APIs for retrieving video objects easily by using cursors. Finally, we implement our low-level storage manager based on SHORE (Scalable Heterogeneous Object REpository) storage system by sunig a standard C++ language under UNIX operating system.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.3
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• pp.144-152
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• 2021

Sanankerto is one of pilot projects for tourism villages in Indonesia due to its natural tourism potential with a 24-ha bamboo forest located in Boon Pring Andeman area. However, the distribution of existing bamboo has never been identified or mapped. Thus, the mana gement is facing difficulty in planning and developing tourism potential as well as spatial management in the area. Therefore, the objectives of this study were to identify and analyze the structure of bamboo vegetation in the Boon Pring Tourism village an d to perform vegetation mapping. The type of research was descriptive exploratory with a cluster sampling technique (i.e., a two-stage cluster) covering an area of ± 10 ha. Bamboo vegetation analysis was performed by calculating diversity index (H'), evenness index (E), and Species Richness index (R). Data were collected through observation and interviews with local people and the manager to determine zonation division. Mapping of bamboo vegetation based on zoning was processed into thematic maps using ArcG is 10.3. Micro climatic factors were measured with three replications for each sub -cluster. Data were analyzed descriptively and quantitatively. Nine species of bamboo identified. Diversity, evenness, and species richness indices differed at each location. Activities of local communities, tourists, and manager determined the presence, number, and distribution of bamboo species. These bamboo distribution maps in three zoning (utilization, buffer, and core) can be used by manager for planning and developing natural tourism potential.