• The KIPS Transactions:PartA
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• v.15A no.6
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• pp.335-344
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• 2008

We propose an adaptive garbage collection technique for hybrid flash memory which has both SLC and MLC. Since SLC area is fast and MLC area has low cost, the proposed scheme utilizes the SLC area as log buffer and the MLC area as data block. Considering the high write cost of MLC flash, the garbage collection for the SLC log buffer moves a page into the MLC data block only when the page is cold or the page migration invokes a small cost. The other pages are moved within the SLC log buffer. Also it adjusts the parameter values which determine the operation of garbage collection adaptively considering I/O pattern. From the experiments, we can know that the proposed scheme provides better performance compared with the previous flash management schemes for the hybrid flash and finds the parameter values of garbage collection close to the optimal values.

• Korean Association of Arts Management
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• no.49
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• pp.65-86
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• 2019

This study investigated the relationship among type of museum space, number of visitors, and number of collections. Museum space has been sorted in various ways(e. g. Seo, 2008; Lee, 2008; Ambrose & Paine, 2012), but this study adopted Lord et al. (2012)'s typology, which has public/non-public and collection/non-collection space, considering that Korean museums' space fits their typology. Using 853 museum data our regression analyses show that public-collection space is positively related to the number of visitors is bigger, while non-public-collection space is positively related to the number of collections. This study has academic and practical implications by showing there are differential relationship among those physical museum characteristics and museum performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.149-152
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• 2004

플래시 메모리에서의 가비지 컬렉션은 유효하지 않은 데이타를 블록단위로 지우고 새로운 데이터를 할당할 수 있는 영역으로 만들어 주는 것을 의미하는데. 이것은 읽기/쓰기 작업에 비해 많은 시간을 요구하므로 빈번한 가비지 컬렉션은 시스템의 성능을 저하시킨다. 본 논문에서는 NAND 플래시 메모리에 데이타 베이스의 레코드 저장방식을 이용하여 데이타를 투플 단위로 저장하였고, 스페어 영역을 변경하여 이러한 작업이 편리하게 진행되도록 하였다. 가비지 컬렉션 시 투플의 크기에 따른 페이지 병합 작업 또한 스페어 영역의 정보를 이용하며, 이것은 실제 활용 가능한 페이지 수를 늘림으로써 가비지 컬렉션의 횟수를 줄이고 성능을 향상시킨다.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.1
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• pp.137-166
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• 2019

The study aims to determine the areas and elements of usability evaluation that reflect the characteristics of the archival contents collections in the National Archives of Korea, and to evaluate the usability of the "Decisions Relating to the Independence Movement" collection for history majors. Through the findings, the relation and importance level that usability evaluation areas and elements have on overall satisfaction can be identified. As a result of this study, the areas of content, search, and interface all had positive effects on overall satisfaction. The interface area holds the greatest influence, and the two elements on each area were found to have a positive effect. On the other hand, users selected the order of importance as "search" first, "contents" second, and "interface" third, showing that interface was considered relatively less important. Based on this, we propose improving the usability direction of the archival contents collection of the National Archives of Korea.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.379-381
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• 2012

중복 제거(deduplication)기법은 저장장치의 공간을 효율적으로 사용할 수 있도록 해 주기 때문에 기존의 스토리지 시스템에서 많이 사용된 기법이다. 최근에는 플래시 메모리 기반의 SSD를 위한 중복 제거 기법도 많이 제안되었지만, 플래시 메모리의 특성을 고려하지 못하고 있다. 본 논문에서는 오프라인 중복 제거 기법을 대상으로 SSD의 특성을 고려하여 가비지 컬렉션의 비용을 절감할 수 있도록 중복 가능성이 있는 데이터와 중복 가능성이 없는 데이터를 온라인에 구분하여 플래시 메모리의 다른 영역에 기록하여 오프라인 중복 제거 후에 가비지 컬렉션 성능을 향상시키는 기법을 제안하였다. 실험결과, 제시된 기법은 가비지 컬렉션 비용인 페이지 이동 횟수를 약 80%이상 감소시켰다.

• The Korean Journal of Archival Studies
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• no.64
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• pp.157-186
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• 2020

RRecords management has focused largely on public records in south korea with a relatively low progress in the collection and management of private records with the enactment of Public Records Act in 1999. This study set out to categorize the records of the Coalition for Democratic Reunification and the People's Movement(DRPM) and develop them into a group collection. For this study, literature reviews, analysis and reorganization of records content, development of a classification system, and expert evaluation were carried out. The findings of this study will contribute to greater efficiency in the search of records about the DRPM by developing a classification system to recategorize its records of various sources and enable their easy access and utilization in a digital archive. In addition, the basic structure of producer-oriented classification can be suggested as an example of the organization of a group collection.

• Journal of the Korean Society for Library and Information Science
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• v.42 no.1
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• pp.253-272
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• 2008

While relevant studies emphasize the significance of user-oriented indexing associated with fulfilling both topical and non-topical needs of individual users, a great number of operational retrieval systems supports only those searches related to subject attributes of the users' needs. Retrieval systems for presidential image collections are not an exception for such a restriction. Upon this reality. this study seeks diversification of access points for presidential images based on descriptors directly presented by potential user groups. Improvements of subject-based descriptors are suggested based on those descriptors identified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.175-178
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• 2008

While read operation on flash memory is fast and doesn't have any constraints, flash memory can not be overwritten on updating data, new data are updated in new area. If data are frequently updated, garbage collection, which is achieved by erasing blocks, should be performed to reclaim new area. Hence, because the number of erase operations is limited due to characteristics of flash memory, every block should be evenly written and erased. However, if data with access locality are processed by cost benefit algorithm with separation of hot block and cold block, though the performance of processing is high, wear-leveling is not even. In this paper, we propose CB-MG (Cost Benefit between Multi Group) algorithm in which hot data are allocated in one group and cold data in another group, and in which role of hot group and cold group is exchanged every period. Experimental results show that performance and wear-leveling of CB-MG provide better results than those of CB-S.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.551-557
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• 2011

In this paper, we propose a stack allocation technique of Android Java objects in order to reduce the number of garbage collection which is one of major reason on Android performance degradation when running applications. The proposed technique is to allocate Java objects into stack rather than heap memory. To do so, stacked objects could escape the garbage collection process. We experiment the proposed technique in the latest Android 2.3 version. For the simulation, we take advantage of the well known Java benchmark, Caffeinemark, and our own. The result shows the performance degradation of Dalvik Virtual Machine execution time caused by the stack allocation of Java objects is very slight and the proposed method considerably reduces the frequency of garbage collection. This will increase application performance and give better user interfaces to Android phone users.

• Annual Conference on Human and Language Technology
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• 1999.10e
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• pp.20-27
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• 1999

본 논문은 정보검색 시스템 평가에 필요한 한국어 문서집합 구축과 적합 문서리스트(relevance file) 생성에 관한 기법을 문서 수집과정부터 평가작업까지 상세히 기술한다. 문서집합은 일반, 사회과학, 과학기술 분야에서 각각 4만 건으로 영역별로 균등히 구축하였으며, 질의 집합도 각 분야에 대해 10개씩 할당하여 총 30개의 질의 집합을 생성하였다. 또한 질의집합은 사용자의 수준을 고려하여 일반인, 영역 전문가, 중고등학생에 해당하는 질의를 생성함으로써 특정 영역, 특정 사용자에 독립적인 문서집합 및 질의집합을 구축하고자 하였다. 생성된 질의를 사용하여 여러 검색기에서 총 38가지의 방법으로 검색을 실시하였으며, 검색결과를 바탕으로 각 질의당 500개의 문서로 이루어진 후보 결과집합을 만든 후 이들을 대상으로 각 질의에 대한 문서의 적합성 평가를 실시하였다. 이 과정을 통해 생성된 적합문서 집합의 유효성을 보이기 위해 후보 문서 리스트 이외의 문서집합에서 적합문서가 존재할 가능성을 확인하였는데 그 방법으로 후보 리스트의 개수 증가에 따른 적합문서 개수의 변동 추세를 알아보았다. 현재 질의 개수를 50개로 확장하는 방향으로 테스트 컬렉션 구축에 대한 연구를 진행 중에 있으며, 일본 NACSIS와의 질의 교환을 통해 질의 개수를 확장할 뿐만 아니라 일본어 질의 또는 한국어 질의에 대해서 한국어 문서, 일본어 문서를 각각 검색할 수 있는 한일 교차언어 문서검색 환경을 구축하고 있다.