• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.710-716
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• 2008

This paper covers the performance evaluation of two flash memory-based file storages, NAND and NOR, which are the major flash types. To evaluate their performances, we set up separate file storages for the two types of flash memories on a PocketPC-based experimental platform. Using the platform, we measured and compared the I/O throughputs in terms of buffer size, amount of used space, and kernel-level write caching. According to the results from our experiments, the overall performance of the NAND-based storage is higher than that of NOR by up to 4.8 and 5.7 times in write and read throughputs, respectively. The experimental results show the relative strengths and weaknesses of the two schemes and provide insights which we believe assist in the design of flash memory-based file storages.

• Journal of Korean Classical Literature and Education
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• no.16
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• pp.207-235
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• 2008

This study investigated the formation of communication education which is based on the contemporary language education. Concretely I watched chronologically the proportion of culture element and behavior element, its change, and the contents of writing education. To achieve this, I took the ancient Greek language education as the main materials. The sophists are right if we think only the empirical world, because of the changeability of external world and the relativity of sense. On the other hand, Platon emphasized the ability of abstract thought which is inherent in the human inside. But today's education only emphasizes the 'expression' which came from the Platonic thought. So students fills their devastated inside with arbitrary idea in this history-forgotten social circumstance. It is very beneficial to make subject have some cultural studies and to enhance the sensation on the world through the writing of representation because these can be good to the growth of subject. It is our-not as educator but as a predecessor of human being-duty to set the catalogue of cultural studies of this age and to make students feel the fundamental harmony and the beauty of the world.

• Cross-Cultural Studies
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• v.37
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• pp.335-360
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• 2014

The purpose of this paper is to investigate whether high-level(level 6) essay-writing questions in Test of Proficiency in Korean (TOPIK) have been presented appropriately so as to enable foreign test-takers to display their Korean writing ability properly, and to provide some suggestions on how those questions need to be changed. To accomplish this purpose, all the essay-writing questions were collected from the 33 TOPIK tests, from the 2nd in 1998 to the 35thin 2014, and analyzed from the perspectives of their topics and formats. The results are that high-level TOPIK essay-writing questions showed a strong tendency to take as their topics Korean sociocultural structures and phenomena, or current issues in Korea, and that they frequently employed guided writing formats by providing preset ideas or/and contexts for test-takers to write in a guided way; such tendencies were analyzed to shed a negative influence on test-takers displaying their writing ability and creativity, because those topics and preset ideas or contexts provided do not allow them to express their own opinions or positions freely. It is suggested that TOPIK essay-writing questions should be changed to deal with objective and general topics which enable test-takers to write freely and logically in Korean based on their experience, because TOPIK is not a test to check whether they have enough background knowledge about the Korean society and culture, but a test to assess their Korean proficiency.

• Smart Media Journal
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• v.8 no.3
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• pp.80-87
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• 2019

Older generations may want a life review, a dynamic process of recall, evaluation, and aggregation, to fulfill their developmental task of "ego-integrity." Writing an autobiography is a tool for a life review based on narrative as "mode of consciousness." This study intends to find out what should be considered so that digital autobiography can fulfill its original role as a tool to achieve ego-integrity for the New Silver Generation. For this purpose, we will first examine theories about the process of ego-integrity through a life review. Then we will analyze different aspects of writing an autobiography including three characteristics of being narrative and the compositional qualities of autobiographical writing. Next, we will review the characteristics of digital narratives autobiography, and highlight some ideas to consider in the study of digital autobiographies for the New Silver Generation.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.461-462
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• 2019

스마트팩토리는 정보통신기술(ICT)를 이용한 공정의 모든 데이터를 수집, 분석하여 제어하고 있다. 기존보다 방대한 양의 데이터를 처리하기 위해 기업들은 하둡을 이용한다. 다양한 크기의 데이터가 나타나는 환경에서 HDFS을 효율적으로 관리하기 위한 적응형 캐시 관리 기법을 제안한다. 제안하는 기법은 데이터 노드의 로컬 디스크의 공간 이용 효율성을 높이고 평균 데이터 크기를 분석하여 데이터 노드 확장시 적합한 블록 크기를 적용할 수 있게 관리한다. 성능 평가를 통해 제안하는 기법의 데이터 노드에서 로컬 디스크 효율 향상과 읽기와 쓰기 속도의 속도에 효과를 보인다.

• Journal of the Korea Society of Computer and Information
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• v.20 no.5
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• pp.1-12
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• 2015

NAND flash memory has being used for storage systems widely, because it has good features which are low-price, low-power and fast access speed. However, NAND flash memory has an in-place update problem, and therefore it needs FTL(flash translation layer) to run for applications based on hard disk storage. The FTL includes complex functions, such as address mapping, garbage collection, wear leveling and so on. Futhermore, implementation of the FTL on low-power embedded systems is difficult due to its memory requirements and operation overhead. Accordingly, many index data structures for NAND flash memory have being studied for the embedded systems. Overall performances of the index data structures are enhanced by a decreasing of page write counts, whereas it has increased page read counts, as a side effect. Therefore, we propose an index management method using a page mapping log table in $B^+$-Tree based on NAND flash memory to decrease page write counts and not to increase page read counts. The page mapping log table registers page address information of changed index node and then it is exploited when retrieving records. In our experiment, the proposed method reduces the page read counts about 61% at maximum and the page write counts about 31% at maximum, compared to the related studies of index data structures.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.157-163
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• 2021

A single write operation in a file system can modify multiple data, but these changes in the file system are not atomically written to disk. Thus, for the consistency of the file system, conventional journaling guarantees crash consistency instead of sacrificing the system performance. It is known that using non-volatile memory as a journal space can alleviate performance degradation due to low latency and byte-level accessibility of non-volatile memory. However, none of the journaling techniques considering non-volatile memory provide scalability. In this paper, journal space on non-volatile memory is divided into multiple regions for scalable journaling, thus dispersing concentrated operations in one region. Second, the journal area-specific operator structure is used to accelerate data write operations to storage devices. We apply the proposed technique to JFS to evaluate it on multi-core servers equipped with high-performance storage devices. The evaluation results show that the proposed technique performs better than the existing technique of the NVM-based journaling file system.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.1
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• pp.27-36
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• 2019

In this paper, we propose a method to find the most similar answer to the user's response from the question-answer database in order to avoid generating a redundant question in retrieval-based automatic question generation system. As a question of the most similar answer to user's response may already be known to the user, the question should be removed from a set of question candidates. A similarity detector calculates a similarity between two answers by utilizing the same words, paraphrases, and sentential meanings. Paraphrases can be acquired by building a phrase table used in a statistical machine translation. A sentential meaning's similarity of two answers is calculated by an attention-based convolutional neural network. We evaluate the accuracy of the similarity detector on an evaluation set with 100 answers, and can get the 71% Mean Reciprocal Rank (MRR) score.

• Journal of Internet Computing and Services
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• v.6 no.1
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• pp.51-64
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• 2005

In this paper, we introduce a system for evaluating similarity of C program source code using method which compares syntax-trees each others. This method supposes two characteristic features as against other systems. It is not sensitive for program style such as indentation, white space, and comments, and changing order of control structure like sentences, code block, procedures, and so on. Another is that it can detect a syntax-error cause of using paring technique, We introduce algorithms for similarity evaluation method and grouping method that reduces the number of comparison, In the examination section, we show a test result of program similarity evaluation and its reduced iteration by grouping algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.221-223
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• 2012

많은 대학과 스토리지 업체에서 고성능 병렬 파일시스템 관련 연구를 활발히 진행하고 있다. 그러나 대학이나 업체에서 연구된 병렬 파일시스템 기술은 상호 호환성에 제약이 있다. 네트워크 파일시스템 관련해서 유일한 표준 기술인 NFS은 최근 pNFS 기능을 포함한 NFSv4.1로 확장되었다. pNFS은 NFS 서버를 거치지 않고 데이터를 병렬적으로 접근함으로써 고성능 입출력을 보장해 주고 있으며 기존 스토리지 기술과의 호환성을 제공하고 있다. 본 연구에서는 pNFS의 성능 평가를 위해서 pNFS을 사용하는 대용량 스토리지 시스템을 구현하고 NFSv4와 NFSv4.1간 성능을 비교한다. 성능 비교는 파일 사이즈와 동시 수행 프로세스 수 별로 수행되며 읽기 및 쓰기 연산에 대한 pNFS의 성능 향상을 확인한다.