• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.63-74
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• 2004

Temporal locality of Web server references is one of the important characteristics to be considered in the design of a Web caching strategy, and it is important to measure the temporal locality exactly. Various methods to estimate the temporal locality have been proposed, however, Web server designers have still troubles in its measurement by using the tools that don't reflect the interarrival time of document requests. In this paper, we propose a measurement tool for short-term temporal locality based on request interarrival time, and discuss the simulation results based on the flares from NLANR and NASA Web sites. The results show that the proposed tool estimates the short-term temporal locality more exactly than that based on a stack.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.369-373
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• 2010

In middle and high school to learn engineering principles to Experiments in space and time constraints and difficulties for the study of engineering principles to the problem is superficial. In this paper, Pascal's principles etc. learning about fluid mechanics and implemented in Web Browser, In connection with flash and HTML, and simulation and virtual experiments is to implement interesting. Of fluid mechanics education through engineering design and web design through the actual web server is implemented on the Internet over broadband. Department of Education, this study fluid dynamics and the Internet will contribute to the development of distance education.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.29-37
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• 2011

Cookie file can be properly protected by designing security zone to enhance the safety of cookie file vulnerable to cyber attacks. In this paper, the model, in which cookie file is stored in the security area and the current visiting page is closely linked with cookie, is proposed to help users utilize in the same existing way, as well as enhance the security of user cookie files. Even if attacker tries to compromise web browser's cookie folder, the security of other cookies can be preserved. It is possible since the folder has the only cookie for the current web page where user is visiting.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.184-190
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• 2008

This paper describes a message model based on XML (eXtensible Markup Language) to present real-time data from sensors and instruments at manufacturing processes for web service. HTML (Hyper Text Markup Language) is inadequate for describing real-time data from process control plants while it is suitable for displaying non-real-time multimedia data on web. For XML-based web service of process data, XML format for the data presentation was proposed after investigating data of various instruments at steel-making plants. Considering transmission delay inevitably caused from increased message length and processing delay from transformation of raw data into defined format, which was critical for operation of a real-time system, its performance was evaluated by simulation. In the simulation, we assumed two implementation models for conducting the transformation function. In one model, transformation was done at an SCC (Supervisory Control Computer) after receiving real-time data from instruments. In the other model, transformation had been carried out at instruments before the data were transmitted to the SCC. Various tests had been conducted under different conditions of offered loads and data lengths and their results were described.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.705-715
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• 2005

A peer-to-peer web caching has been studied recently as it can reduce the traffic converged on the server side and can support the traditional web caching model. Although the peer-to-peer web caching has the merit of having additional cache space from the local caches of peers without additional infrastructure, several constraints such as dynamic participation and local caching strategy caused by the autonomy of peers in peer-to-peer networks nay limit the performance of the peer-to-peer web caching. To overcome these limitations, we propose an efficient directory-based peer-to-peer web caching system under dynamic participation of peers. In the proposed caching system, we present new peer selection and replica management schemes by introducing the concept of the object lifetime in P2P networks. We evaluate the effectiveness of the proposed system through trace-driven simulations with a web log dataset. Simulation results show that the proposed system has higher accuracy and fewer redirection failures than the conventional directory-based P2P web caching system in feasible peer-to-peer networks.

• Steel and Composite Structures
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• v.25 no.6
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• pp.671-684
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• 2017

Elastic-plastic shear buckling behaviors of the web-post in a Castellated Steel Beam (CSB) with hexagonal web openings under vertical shear force were investigated further using Finite Element Model (FEM) based on a sub-model, which took the upper part of the web-post under horizontal shear force to represent the whole web-post under vertical shear force. A simplified design method for the web-post elastic-plastic shear buckling strength was proposed based on simulation results of the sub-model. Proper boundary conditions were applied to the sub-model to assure that its behaviors were identical to those of the whole web-post. The equation to calculate the thin plate elastic shear buckling strength was adopted as the basic form to build the design equation for elastic-plastic buckling strength of the sub-model. Parameters that might affect the elastic-plastic shear buckling strength of the whole web-post were studied. After obtaining the vertical shear buckling strength of a sub-model through FEM, the shear buckling coefficient k can be obtained through the back analysis. A practical calculation method for k was proposed through curving fitting the parameter study results. The elastic-plastic shear buckling strength of the web-post calculated using the proposed shear buckling coefficient k agreed well with that obtained from the FEM and test results. And it was more precise than those obtained from EC3 based on the strut model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.115-125
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• 2003

As Web services are generally open for external uses and not filtered by Firewall, these result in attacker's target. Web attacks which exploit vulnerable web-applications and malicious users' requests cause economical and social problems. In this paper, we are modelling general web service usages based on user-web-session and detect anomal usages with Bayesian estimation method. Finally we propose SAD(Session Anomaly Detection) for detection unknown web attacks. To evaluate SAD, we made an experiment on attack simulation with web vulnerability scanner, whisker. The results show that the detection rate of SAD is over 90%, which is influenced by several features such as size of window or training set, detection filter method and web topology.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.04a
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• pp.101-107
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• 2000

SimBox는 웹을 기반으로 한 원격 교육 시뮬레이션 도구로서 시뮬레이션 수행 절차에 익숙하지 않은 피교육자들에게 시각적 모델 개발 환경을 제공하여 쉽게 시뮬레이션 모델을 제작할 수 있도록 하였다. 모델 개발을 위해 클라이언트는 자바의 드래그 앤 드롭을 이용하여 시뮬레이션 모델들의 추가/삭제를 용이하게 하였고, 시뮬레이션 코드 작성을 서버가 대신함으로써 피교육자의 시뮬레이션 코드 작성에 대한 부담을 줄여주었다. 또한 컴포넌트 기반의 모델을 개발해 재사용이 가능하며, 자바를 이용해 웹 환경에서 시뮬레이션의 진행상황을 애니메이션을 통해 효과적으로 시각화 할 수 있다.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.158-163
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• 1999

본 연구는 웹상에서 삼차원 객체들을 쉽게 생성시킬 수 있는 중요한 방법 중의 하나가 VRML에 의한 방법이다. 본 연구에서는 웹기반 환경하의 삼차원 객체의 생성 및 이동 또는 변형에 대한 시뮬레이션기법을 다룬다. 간단한 부품을 웹상에 표현하기 위해 제작 도구를 이용하여 작성한 프로그램을 VRML 파일로 변환하여 작성한 예를 제시하고 이때 발생되는 문제점과 이에 대한 해결 방안을 제시한다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.108-116
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• 1995

A tension control strategy for a multi-span web transport system is proposed. This strategy is developed by using the tension transfer phenomena in multi-span systems. The performance of this control strategy is compared with that of an existing control strategy through a computer simulation. A real-time software is designed based on the proposed tension control stration of master speed drive in tension control is demonstrated.