• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.60-65
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• 2007

유비쿼터스 컴퓨팅은 일상생활 속에 편재해 있는 PDA 또는 모바일 폰 등의 무선 단말기를 이용하여 사용자가 언제, 어디서나 유용한 서비스를 받을 수 있는 환경을 제공한다. 이는 대용량 데이터베이스에 저장된 지능형 멀티 모바일 에이전트의 통신 데이터를 분석하여 모바일 유저의 위치에 따른 요청된 유용한 서비스정보를 추출할 수 있게 되었으며, 이를 통한 효율적인 사용자 서비스는 물론 광고 등의 새로운 이익 창출로 이어져왔다. 그러나 기존 위치 정보만을 이용한 서비스정보의 추론은 단순히 통계적인 빈발 행동패턴만을 추출하여 시간에 따른 사용자의 서비스 요청에 능동적으로 대처할 수 없을 뿐만 아니라 원치 않는 서비스정보를 제공하는 문제점을 야기 시켰다. 이 논문에서는 시간을 고려한 모바일 사용자의 유용한 행동패턴 추출을 위한 효율적인 마이닝 기법인 시간대별 모바일 사용자 행동패턴 및 메모리 적재에 용이한 새로운 콤팩트한 데이터 구조를 제안한다. 이는 사용자의 동적인 움직임에 따른 실시간적 서비스를 가능하게 하며, 더 나아가 유비쿼터스 컴퓨팅 환경에서 중요한 이슈인 데이터의 메모리 적재가 용이 할 뿐만 아니라 접근속도의 향상 및 메모리 사용이 적다는 이점이 있다.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.259-265
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• 2008

This research starts from the questioning of current housing development situation on hilly sites in Korea. It aims to investigate various design techniques of row-rise housing as an alternative housing type on hilly sites. Several generic solutions are proposed by considering the density of dwelling, parking plans, exterior space and access patterns, making full use of geographical features of hilly site and existing facilities. In order to promote development feasibility of proposed plans, the efficiency of the proposed techniques are verified in terms of development density, enhancement of community space, habitability of housing.

• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.13-17
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• 2004

As the usage of wireless LAN becomes common in working environment, the number of database systems that support both wired and wireless users increases rapidly. The characteristics of wireless LAN that its speed is slow relatively comparing to wired network and the users in its environment connects to different communication points as they moves creates another challenge to be resolved in database systems. In the environment of hybrid communication systems, wired and wireless for voluminous data amount and a number of users, the two layer architecture of the conventional client-server database systems has limitation in the system performance. This is due to that server is the only point of data service in client-server database systems. In this paper, we discuss a new extended database system architecture that data services are distributed among servers and clients based on user database access patterns in order to improve system performance. We analyze the expected system performance by using simulation technique and prove the practical utilization of the system by demonstrating experimental results.

• Journal of the Ergonomics Society of Korea
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• v.24 no.1
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• pp.19-26
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• 2005

Mobile internet access using such devices as PDAs and cellular phones becomes popular as mobile technologies grow. However, the characteristics of small screen devices such as small screen size and pen-based input cause many usability problems. In this study, a human factors experiment was conducted to identify the factors affecting the usability of information search on a PDA. Factors manipulated in the experiment included use of wheel equipment, scroll dimension, and screen orientation. Task completion time, error frequency, and subjective satisfaction level were measured. In addition, various users' behavioral patterns such as scanning routes and mainly used scrolling methods were analyzed. Scroll dimension has a significant effect on task completion time. Scroll equipment and screen orientation affect subjective satisfaction level. The results could be applied to designing information structure of web sites for mobile use by providing vertical scroll and using external scroll equipments.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.367-375
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• 2014

In this paper, a novel triple-band circular-ring monopole antenna with a half-circular ring and ground slot for wireless local area network/Worldwide Interoperability of Microwave Access (WLAN/WiMAX) applications is proposed. The proposed antenna consists of one circular ring, a half-circular ring and a rectangular slot in the ground plane. Based on the concept, a prototype of the proposed triple-band antenna was designed, fabricated and tested. The numerical and experiment results demonstrated that the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. Furthermore, this paper presents and discusses the 2D radiation patterns and 2D gains according to the results of the experiment.

• International Journal of Knowledge Content Development & Technology
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• v.8 no.2
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• pp.23-36
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• 2018

Institutional repositories (IR) are promising to be extremely advantageous to scholars especially in developing countries. IR initiatives started in India during the late nineties and the popularity of this concept is growing rapidly in the higher educational and research institutions to disseminate newly emerging knowledge and expertise. The purpose of this paper is to critically analyze the network links of IR websites among four IITs that are registered in open DOAR (Directory of Open Access Repositories) web portal. The Institutional Repositories chosen for the study are IIT Delhi, IIT Hyderabad, IIT Bombay, and IIT Kanpur. The analysis of the study focused on standard graph and network cohesion metrics, such as density, diameter, eccentricity and distances, and clustering coefficient; for an even more detailed analysis advanced centrality measures and fast algorithms such as clique census are used.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.88-91
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• 2003

A fuel spiking test was performed to measure the surge margin of gas turbine engines. The surge marin was mainly determined by the compressors and fuel spiking was used to change the operating point in the compressor characteristic map while speed remained constant. To access the surge margin region different spiking signals were applied by modulations of time(frequency) and fuel flow rate(amplitude). The test results showed good agreements with expected fuel spiking patterns and possibility of further studies.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1332-1341
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• 1999

Rapid expansion of network and increment of computer system access cause computer security to be an important issue. Hence, the researches in intrusion detection system(IDS)are active to reduce the risk from hackers. Considering IDS, we propose a new IDS model(DABIDS : Distributed Agent Based Intelligent intrusion Detection System) based on distributed intrusion detecting agents. The DABIDS dynamically collects intrusion behavior knowledge from each agents when some doubtable behaviors of users are detected and make new agents codes using intrusion scenario data base, and broadcast the detector codes to the distributed intrusion detecting agent of all node. This DABIDS can efficiently solve the problem to reduce the overhead for training detecting agent for intrusion behavior patterns.

• International Journal of Safety
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• v.10 no.1
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• pp.32-35
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• 2011

Lifting capacity and difficulty of task are influenced by body posture. In RULA and REBA, the body was divided into segments which formed two groups, A and B. Group A includes the upper and lower arm and wrist while group B includes the neck, trunk and legs. This ensures that whole body posture is recorded so that any awkward or constrained posture of the legs, trunk or neck which might influence the posture of the upper limb. This study aimed to measure MVC (maximum voluntary contraction) and subjective judgment in psychophysical method (Borg's scale) according to trunk and upper arm angle and to analyze results statistically. The results of this study were that lifting capacity was more influenced by interaction of body posture rather than angles of each part, and MVC variation according to trunk and upper arms angles should different patterns. This means that we consider the interaction of trunk angles and upper arm angles when we access risk factors of the postures. This survey would be also the basic data to evaluate difficulty of lifting tasks according to body postures ergonomically.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2000.11a
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• pp.151-157
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• 2000

본 논문에서는 웹사이트에 접근하는 사용자 접근 패턴을 학습하여 정보 제공이 보다 용이한 구조로 자동 개선시켜 나가는 적응형 웹사이트를 구축하고자 한다. 즉, 기존 웹사이트의 구조를 가늠한 한 파괴하지 않는 범위 내에서 김 사이트를 변경하고자 관련성은 높으나 접근 경로가 긴 문서들의 클러스터를 찾아내고, 이들에 대한 별도의 색인 페이지를 생성하여 웹사이트 내에 위치시킨다. 이를 위하여, 먼저 대용량의 웹 서버 로그 데이터들을 대상으로 순차 패턴 탐색 방법인 AprioriAll 알고리즘을 적용함으로써 웹문서간의 충분한 연관성 지지도를 갖는 사용자 순차 접근 패턴을 분석해낸다. 사용자 순차 접근 패턴 분석을 통해 관련성 있는 문서들의 집합을 알아낸 후, 웹사이트의 하이퍼 링크 구조 정보를 고려하여 접근 경로가 긴 문서들만을 골라 웹 문서 클러스터를 생성시킨다. 이러한 웹문서 클러스터들에 대한 색인 페이지를 추가 생성하여 제공함으로써 사용자들의 보다 효과적인 정보 접근을 지원한 수 있는 웹사이트로의 변경이 가능하다.