• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.533-535
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• 1998

가상 다중 세그먼트 (Virtual Multi-Segment)란 하나의 LAN이 라우터나 방화벽을 사용하지 않고 가상적으로 여러 개의 세그먼트로 나뉘어진 것을 의미한다. 일반적으로 같은 LAN에 속한 호스트들일지라도 다양한 보안 정책을 가지게 되는데 그 결과로 우회 경로 공격(bypass path attack)이 가능해지고 (Hierarchical)방화벽 시스템을 구성하여 다른 보안 정책을 가진 세스먼트마다 방화벽을 구축하고 있는데 이 방식은 방화벽 시스템을 구성하여 다른 보안 정책을 가진 세그먼트마다 방화벽을 구축하고 있는데 이 방식은 방화벽을 여러 개 설치해야 하는 문제가 있다. 이런 문제를 해결하기 위해 본 논문에서 방화벽을 통해 지나오는 각 연결에 대해서 회선체인을 구성하는 기법을 이용하여 가상적인 다중 세그먼크를 구성한다. 회선체인구성을 효과적으로 수행하기 위해 Thumbpint기법을 사용하는데 이 기법은 동일한 시간대에 모든 회선이 갖는 내용에 대한 요약을 만들어 그 요약들을 가지고 어떤 회선들이 같은 내용을 가지고 있는지를 판단하여 회선체인을 구성하는 기법이다. 본 논문에서 가상 다중 세그먼트 방화벽을 설계와 구현하였다.

• Journal of the Korea Computer Industry Society
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• v.5 no.2
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• pp.217-226
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• 2004

This paper proposes the electric stimulus tactile apparatus system(TESTAS) loaded on the haptic interface using ultrasonic motors (USMs) To touch the virtual object like wall in graphic, the 6 DOF haptic interface provides force feedback to users as if it is real. But the case of sharp virtual object like a puncture, it could not provided the sense of pain, but only the reaction-force. After the TESTAS had been loaded on this haptic interface, it could provide not only the force but also the pain to users. In this way, when users take the haptic and tactile informations at the same time, they easily have a correct understanding of virtual object.

• Information and Communications Magazine
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• v.17 no.3
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• pp.97-110
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• 2000

인터넷은 본질적으로 신뢰할 수 없는 네트웍들의 집합체로, 정보의 흐름을 통제하기가 대단히 어렵기 때문에, 인터넷에 산재한 자원을 충분히 활용하면서, 내부의 중요한 자원을 인터넷으로부터 보호해 줄 수 있는 인터넷 보안이 가장 심각한 문제로 대두되고 있다. 본 고에서는 현재 인터넷 보안의 주류를 이루는 있는 가상사설망(VPN : Virtual Private Network)과 방화벽(Firewall), 그리고 방화벽의 부족한 부분을 보강해 줄 수 있는 침입탐지시스템(IDS: Intrusion Detection System)에 대한 기본 구현 기술들을 비교 분석해 본다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1752-1758
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• 2006

Racing game requires plausible physics model that can be simulated in realtime. Minor artifacts in racing games are easily noticed, and any kinds of games should work interactively. It is difficult to model the accurate tire-ground physics and to integrate the model into realtime environments. In this paper, an efficient and effective 'imaginary wall' model was proposed. The method can be easily implemented because of the simplicity of the physical model used, and the result of the simulation is realistic enough for the racing games.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5338-5343
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• 2013

In a haptic system, a virtual wall is modeled as a virtual spring. The larger the stiffness of the virtual spring is, the more improved the reality of the virtual wall is, but the more unstable the haptic system becomes. This paper shows how to increase the stiffness of the virtual spring while the stability of the haptic system is guaranteed and shows the effects of a mass (Md) and a damper (Bd) of a haptic device on the stability when first-order hold method is applied and a virtual wall is modeled as a virtual spring (Kw). The simulation results show the boundary of the virtual spring is proportional to the square root of the mass (Md) and the damper (Bd) while maintaining the stability. The relation among the virtual spring (Kw), the mass (Md) and the damper (Bd) of the haptic device, and sampling time (T) is inferred as $K_w{\leq}{1.611M_d}^{0.50}{B_d}^{0.50}T^{-1.51}$, by using the simulation results. The maximum available stiffness of the virtual spring in first-order hold method is larger than in zero-order hold method. So the reality of the virtual wall can be improved.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.17-21
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• 2014

This paper presents the effects of the time delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a time delay model. In this paper, the time delay is considered as the computational time delay that is assumed to be as much as the sampling time. As the time delay increases, the maximal available stiffness of a virtual wall model is reduced reversely. The relation among the time delay and the maximum available stiffness, the mass and the damper of the haptic device are analyzed using the MATLAB simulation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.237-249
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• 2002

The wall system that is composed only of reinforced concrete walls and slabs is adopted on many high-rise apartment buildings recently constructed. In the apartment buildings, a shear wall may have one or mote openings for functional reasons. Many researches on the analysis of shear wall with openings were performed. But, some restrictions prevent those research results being applied to practical analysis and design procedure. It is necessary to use subdivided finite elements lot accurate analysis of the wall system with openings. But it would cost tremendous amount of analysis time and computer memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method which can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, matrix condensation technique and fictitious beam technique. Analyses of example structures having various types of openings were performed to verify the efficiency of proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.351-365
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• 2002

The box system that is composed only of reinforced concrete walls and slabs we adopted on many high-rise apartment buildings recently constructed in Korea. And the framed structure with shear wall core that can effectively resist horizontal forces is frequently adopted for the structural system for high-rise building structures. In these structures, a shear wall may have one or more openings for functional reasons. It is necessary to use subdivided finite elements for accurate analysis of the shear wall with openings. But it would take significant amount of computational time and memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method that can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, substructure, matrix condensation technique and fictitious beam technique. Three-dimensional analyses of the box system and the framed structure with shear wall core having various types of openings were performed to verify the efficiency of the proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.273-276
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• 2022

정보통신 기술의 발달은 보안 위협의 증가라는 결과를 함께 가져왔고 국내뿐만 아니라 국외로도 보안 정책 관리에 대한 필요성이 지속적으로 강조되었다. 본 논문에서는 여러 보안 장비 중 방화벽 정책 관리를 도울 수 있는 보조 시스템을 개발하였다. 이를 위해 오픈소스 방화벽 솔루션을 가상 환경에 구축하고 방화벽 정책을 추출 및 분석하여 미 동작 정책과 중복 정책을 식별하였다. 이러한 점검 보조 도구를 정책 관리에 이용한다면 낮은 이해도로 인한 Human Error의 발생을 가능한 줄이고 그 결과, 외부 위협의 최소화를 이룰 것이라 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1087-1090
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• 2008

Web 경계를 허무는 새 시대에 맞추어 라이프스타일은 급속히 변화하고 있다. 가상의 3D 복합 서비스는 현실과 다름없는 또 하나의 삶을 제공함으로써, 가상세계와 현실세계의 경계를 없애고 있고 이전 많은 사람들이 제안하고 예상했던, 현실의 정보가 가상세계에서 또한 다름 없는 데이터로 존재함으로써 가상세계와 현실세계 사이의 벽을 허물고 그 차이를 느끼리 못 하도록 하는 연구를 하고자 하였다. 우선 손쉽게 제시할 수 있는 실험을 통하여 그 가능성을 판단해 보고자 하였으며, 간단한 예로써 현실세계를 대표할 모바일 장비와 가상 현실세계의 대표적인 예인 SecondLife 두 가지 시스템의 접목을 통하여 가상현실 세계와 현실간의 데이터 공유 환경을 만들고 정보를 공유를 통하여, 얻을 수 있는 장점들과 활용방안에 대하여 찾고자 한다.