• The Journal of Korean Association of Computer Education
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• v.6 no.4
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• pp.85-93
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• 2003

This paper proposes an item based learning system using e-mail in order to motivate learners effectively and avoid the bottleneck problem under highly competitive access situations such as the traditional web based learning. The proposed system has th ree features as follows: first, through e-mail, a learner receives test items depending on his/her level, submit an answer sheet, and then identify an assessment with help messages. Secondly, on the web, an instructor easily constructs item database without any other tools and monitors the status of each learner by identifying the learners' record. Finally, an easy-to-use interaction mechanism enhances the inter-activity between learners and instructors, and the usability of Q&A(Question and Answer) service by incorporating e-mail into the web bulletin board.

• The KIPS Transactions:PartD
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• v.8D no.3
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• pp.221-232
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• 2001

Due to rapid advance of wireless communication technology, demand on data services in mobile environment is gradually increasing. Caching at a mobile client could reduce bandwidth consumption and query response time, and yet a mobile client must maintain cache consistency. It could be efficient for the server to broadcast a periodic cache invalidation report for cache consistency in a cell. In case that long period of disconnection prevents a mobile client from checking validity of its cache based solely on the invalidation report received, the mobile client could request the server to check cache validity. In doing so, some schemes may be more efficient than others depending on the number of available channels and the mobile clients involved. In this paper, we propose new cache consistency schemes, effects, efficient especially (1) when channel capacity is enough to deal with the mobile clients involved or (2) when that is not the case, and evaluate their performance.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.359-366
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• 2013

In this paper, we studied how the data obesity can affect in which the response speed of database gradually slows down. Our research is performed by analyzing how the game data infrastructure is well-formed. Although there are a variety of ways to evaluate to measure the level of infrastructure, we performed with real information system. We analyzed data obesity by comparing the entity-relationship models between the products of real game information system and newly modeled databases. We could find data obesity is over 60% among overall average of game information system. It shows that 45% higher than standard obesity which is 15%. In this paper, data redundancy rate after performing the procedure of the data modeling was 41% resulting in an improvement of 23% compared to 64% of an existing model.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.31-38
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• 2008

Recently the necessity of time history analyses is increasing for the seismic analyses of a structure, and the seismic design provisions of IBC2003, ASCE and KBC2005 require the use of a minimum of seven earthquake records for the time history analyses. Earthquake records for the time history analyses could be selected from the database of the field-measured earthquake records having similar site conditions with the designed site, or from simulated sites satisfying the design spectrum. However, in this study seven earthquake records were generated using 50 earthquake records, classified as records measured at the rock, in the database of the Pacific Earthquake Research Center (PEER). Seven earthquake records were first selected by the least squares fitting method comparing the scaling factored response spectra with the specified design spectrum, and a family of seven artificial time history earthquake records was ultimately generated by multiplying scaling factors, which were calculated by the least squares fitting method and the SRSS averaging method, to the corresponding selected earthquake records.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.89-97
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• 2011

In semantic web information system like ontology that access distributed information from network, efficient query processing requires an advanced caching mechanism to reduce the query response time. P2P network system have become an important infra structure in web environment. In P2P network system, when the query is initiated, reducing the demand of data transformation to source peer is important aspect of efficient query processing. Caching of query and query result takes a particular advantage by adding or removing a query term. Many of the answers may already be cached and can be delivered to the user right away. In web environment, semantic caching method has been proposed which manages the cache as a collection of semantic regions. In this paper, we propose the semantic caching technique in cluster environment of peers. Especially, using schema data filtering technique and schema similarity cache replacement method, we enhanced the query processing efficiency.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.422-431
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• 2004

In recent years, different models in data delivery have been explored in mobile computing systems. Particularly, there were a lot of research efforts in the periodic push model where the server repetitively disseminates information without explicit request. However, average waiting time per data operation highly depends on the length of a broadcast cycle and different access pattern among clients may deteriorate the response time considerably. In this case, clients are preferably willing to send a data request to the server explicitly through backchannel in order to obtain optimal response time. We call the broadcast model supporting backchannel as hybrid broadcast. In this paper, we devise a new transaction processing algorithm(O-PreH) in hybrid broadcast environments. The data objects which the server maintains are divided into Push_Data for periodic broadcasting and Pull_Data for on-demand processing. Clients tune in broadcast channel or demand the data of interests according to the data type. Periodic invalidation reports from the server support maintaining transactional consistency. If one or more conflicts are found, conflict orders are determined not to violate the consistency(pre-reordering) and then the remaining operations have to be executed pessimistically. Through extensive simulations, we demonstrate the improved throughput of the proposed algorithm.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.303-309
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• 2010

We proposes a new approach for testing the self visual-acuity by using the KS standard optotype. The proposed system provides their hand-gesture recognition method for the convenient response of subjects in the visual acuity measurement. Also, this system can measure a visual-acuity that excludes the examiner's subjective judgement or the subject's memorized guess, because of presenting a random optotype automatically by computer without a examiner. Especially, Our system guarantees the reliability by using the KS standard optotype and its presentation(KS P ISO 8596), which is defined by the Korea Standards Association in 2006. And the database management function of our system can provide the visual-acuity data to the EMR client easily. As a result, Our system shows the 98% consistency in the limit of the ${\pm}1$ visual-acuity level error by comparing the visual-acuity chart test.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.159-181
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• 2006

본 연구에서는 청주와 그 인근 지역에서 정보시스템을 개발하거나 운영하고 있는 업체의 IS 실무자들에게 (1) IS 실무자의 업무 수행 성과, (2) 소프트웨서 및 IT 전문기술수준, (3) IS 지식 및 능력 수준, 그리고 (5) 재교육 수요에 대해서 설문 조사하였다. 본 연구의 조사 대상자들은 주로 Sl(system integration) 업체에 종사하는 IT(information technology) 실무자들과 e-Business를 수행하는 일반 기업에서 전산 업무를 담당하고 있는 실무자들이며, 구체적으로는 전산시스템 운영자, 시스템/데이터베이스 분석/설계자, 어플리케이션/웹 프로그래머, 최종사용자 지원 담당자, e-Business를 위한 IT 지원 인력 등이다. 조사 결과는 다음과 같다. 충북 지역에서 IS 실무자들은 자신들의 업무를 성공적으로 수행하기 위한 지식 및 기술의 다양한 영역에서 광범위하게 지식 및 기술의 결핍을 느끼고 있으며, 자신의 업무 성과가 전반적으로 좋지 않다고 판단하고 있고, 업무 관련 지식 및 기술에 대한 재교육의 필요성을 강하게 느끼고 있다. 또한, 충북 지역의 IS 실무자들은 주된 활동이나 업무가 시스템 개발과 유지보수, 최종 사용자 지원 등의 활동이며, 이에 대한 최신의 기술과 고객 중심의 시각화된 도구(GUI)를 제공하는데 많은 시간을 투자하며, 기존의 반복적인 개발 업무에서 점차 경력이 쌓임에 따라 고객 중심적인 새로운 시스템 개발을 위한 기획과 관리에 많은 관심을 기울이고 있으나, 조직 운영 및 의사결정 등과 같은 기술/지식들에는 낮은 관심을 보였다. IT전문 기술들 중 IS 실무자들이 필요로 하고 보유해야 한다고 응답한 기술들은 대다수가 웹 개발에 관련된 기술이며, IS 실무자들은 대규모 프로젝트의 수행에 필요한 공동 작업 수행 능력의 제고와 그를 위한 재교육에 높은 관심을 나타내었다. 본 조사는 충북의 IS 실무자들을 위한 대학 교육과 재교육을 포함하는 최적의 평생 교육계획 수립을 위한 기초적이고 필수적인 정보를 제공할 것으로 기대된다.

• The Journal of the Korea Contents Association
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• v.3 no.2
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• pp.57-64
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• 2003

A Web Service is an URL addressable set of functionality that is exposed over a network to serve as a building Hock for creating distributed applications. SOAP is a protocol that Web Service consumers often use, when they request and response to a Web Service, and it is a lightweight, XML-based protocol over HTTP for exchange to information in decentralized, distributed environments. A Web Service is very useful forimplementing common functions in especially a large size business area, because it is invoked by a protocol like HTTP or SOAP that we easily use, and by an XML-based data format In this paper, we implement Web Services that process dip data by computers in enterprise accounts in order to enhance the transparency and productivity of enterprises. we analyse the structure of slip data, design dip database, implement stored procedures for manipulating data of slip database, and make thorn controlled by Web Services. The result of this paper will contribute to the standardization and activation of accounting process systems for e-business area.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.6
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• pp.15-23
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• 2020

While research activities in the agricultural field for climate change are being actively carried out, smart agriculture using information and communication technology has become a new trend in line with the Fourth Industrial Revolution. Accordingly, research is being conducted to identify and respond to signs of abnormal growth in advance by monitoring the stress of crops in various outdoor environments and soil conditions. There are also attempts to analyze data collected in real time through various sensors using artificial intelligence techniques or big data technologies. In this paper, we propose a big data model that is effective in analyzing the growth environment informations and biometric information of crops by using the existing relational database for big data analysis. The performance of the model was measured by the response time to a query according to the amount of data. As a result, it was confirmed that there is a maximum time reduction effect of 23.8%.