• 한국정보통신학회논문지
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• 제8권2호
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• pp.310-323
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• 2004

In this paper, we extend the multiple time scale control framework to window-based congestion control, in particular, TCP This is performed by interfacing TCP with a large tine scale control nodule which adjusts the aggressiveness of bandwidth consumption behavior exhibited by TCP as a function of "large time scale" network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by RTT Our contribution is threefold. First, we define a modular extension of TCP-a function call with a simple interface-that applies to various flavors of TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that multiple time scale TCP endows the underlying feedback control with preactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of three traffic control dimensions-tracking ability, connection duration, and fairness-on performance. Performance evaluation of multiple time scale TCP is facilitated by a simulation bench-mark environment which is based on physical modeling of self-similar traffic.

• 한국정보통신학회논문지
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• 제19권5호
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• pp.1144-1150
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• 2015

프레즌스(Presence) 정보는 사용자의 온라인 상태, 현재 위치, 네트워크 접속 방식 및 접속 주소 등 사용자에 관한 다양한 내용을 제공하며 XMPP(Extensible Massaging and Presence Protocol) 기반 프레즌스 정보와 SIP(Session Initiation Protocol) 기반 프레즌스 정보의 두 종류가 사용된다, 본 논문에서는 이 두 종류의 프레즌스 정보를 모두 처리 할 수 있는 XMPP/SIP 프레즌스 서비스 시스템에서 서버 부하 증가에 따른 확장성의 제한을 해결하기 위하여 사용자 수의 증가에 따라 동적으로 서버가 추가되고 각 서버의 부하를 효율적으로 제어 할 수 있는 새로운 다중 서버 구조 방식을 제안하였다. 이 방식에서는 부하 제어를 위한 새로운 XMPP 스탠자 구조와 SIP 프레즌스 정보 데이터 구조가 설계되었고, 동적 서버 제어를 위한 각 서버와 사용자 사이의 메시지 교환 절차가 제시되었다. 제안된 시스템의 성능은 시뮬레이션 실험을 통하여 분석하였다.

• 융합보안논문지
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• 제22권4호
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• pp.169-178
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• 2022

도메인이 여러 개로 구성된 멀티 네트워크를 운영하는 조직에서는 단일 화면 상에 다수의 네트워크 토폴로지를 시각화하여 전체 노드들과 링크들을 감시할 수 있는 기능이 필요한데, 도메인간의 연결점이 없는 토폴로지를 단일 화면 상에 표시하는 것은 간단하지가 않다. 게다가, 다수의 네트워크 형상들을 단일 화면 상에 실제와 같은 물리적 모습으로 표시하는 것은 어렵기 때문에, 멀티 도메인 네트워크를 하나의 화면을 통해 관리하는데는 어려움이 있다. 본 연구에서는 멀티 도메인 환경에서 노드간의 최소 연결 정보만을 이용하여 토폴로지를 시각화하는 효율적인 방법을 제안한다. 이 방법은 네트워크를 구성하는 노드들의 중심성 지수를 활용하여 도메인별 중심 노드를 찾고, 자식 노드들과의 연결정보를 재귀적으로 탐색하여 토폴로지를 생성한다. 화면 상의 도메인별 토폴로지 표시 영역은 자식 노드들의 가중치의 합으로 계산 및 동적 분할되고, 가상의 Root 노드를 활용하여 3D 공간 상에 전체 노드들을 배치함으로써 멀티 도메인 토폴로지를 시각화한다. 이 방법은 노드간의 최소 연결 정보만을 이용하는 단순한 방법이지만, 멀티 도메인 네트워크의 물리적 형상을 유지하면서 하나의 화면에 표시할 수 있는 효율적인 토폴로지 시각화 방법이다.

• Structural Engineering and Mechanics
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• 제20권6호
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• pp.695-712
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• 2005

Hybrid coupled shear walls in tall buildings are known as efficient structural systems to provide lateral resistance to wind and seismic loads. Multiple hybrid coupled shear walls throughout a tall building should be joined to provide additional coupling action to resist overturning moments caused by the lateral loading. This can be done using a coupling beam which connects two shear walls. In this study, experimental studies on the hybrid coupled shear wall were carried out. The main test variables were the ratios of coupling beam strength to connection strength. Finally, this paper provides background for rational design guidelines that include a design model to behave efficiently hybrid coupled shear walls.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.261-264
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• 1993

To reconstruct the real 3-D shape from the 3-D measurement data from the multiple directions, the rconstruction of the object on the basis of the mosaic processing of the 3-D measurement data are proposed. In this method, to conduct the reconstruction, the connection points have to be identified among the over-lap area between adjacent 3-D data. In this study, the simple image matching method is adopted for the identification of connection points, and this method is verified from numerical experiments.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2001년도 추계학술발표논문집 (하)
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• pp.1481-1484
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• 2001

Most implementations of HTTP servers do not distinguish among requests for hypermedia data from different clients. Commercialization of Web site is becoming increasingly common. Therefore providing quality of service with members paying to the site is often an important issue for the hosts. For some uses, such as web prefetching or multiple priority schemes, different levels of service are desirable. We propose server-side TCP connection management mechanisms to provide two different levels of Web service, high and regular levels by setting different timeout for inactive connection. Therefore this mechanism can effectively provide different service classes even in the absence of operating system and network support.

• 대한의용생체공학회:의공학회지
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• 제26권5호
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• pp.301-307
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• 2005

We introduce a new multimedia telemedicine system which is called Telemedicine for Real-time Emergency Multi-consultation(TREM), based on multiple connection between medical specialists. Due to the subdivision of medical specialties, the existing one-to-one telemedicine system needs be modified to a simultaneous multi-consulting system. To facilitate the consultation the designed system includes following modules: high-quality video, video conferenceing, bio-signal transmission, and file transmission. In order to enhance the operability of the system in different network environment, we made it possible for the user to choose appropriate data acquisition sources of multimedia data and video resolutions. We have tested this system set up in three different places: emergency room, radiologist's office, and surgeon's office. All three communicating systems were successful in making connections with the multi-consultation center to exchange data simultaneously in real-time.

• Journal of information and communication convergence engineering
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• 제18권3호
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• pp.183-187
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• 2020

The general Wi-Fi network connection structure is that a number of IoT (Internet of Things) sensor nodes are directly connected to one AP (Access Point) node. In this structure, the range of the network that can be established within the specified specifications such as the range of signal strength (RSSI) to which the AP node can connect and the maximum connection capacity is limited. To overcome these limitations, multiple middleware bridge technologies for dynamic scalability and load balancing were studied. However, these network expansion technologies have difficulties in terms of the rules and conditions of AP nodes installed during the initial network deployment phase In this paper, an intelligent edge computing IoT device is developed for constructing an intelligent autonomous cluster edge computing network and applying it to real-time road danger context aware and notification system through an intelligent risk situation recognition algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.315-318
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• 2003

This paper proposes a switching control method applicable to any affine, 2nd order nonlinear system with single input. The key contribution is to develop a control design method which uses a piecewise continuous Lyapunov function non-increasing at every discontinuous point. The proposed design method requires no restrictions except full state availability. To obtain a non-increasing, piecewise continuous Lyapunov function, we change the sign of off-diagonal term s of the positive definite matrix composing the former Lyapunov function according to the sign of the Inter-connection term. And we use the solution of inequalities which guarantee each Lyapunov function is non-increasing at any discontinuous point.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.166-169
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• 2004

In this paper show how to design a redundant robot which is suitable for the multiple task without any constraints on the workspace. The implementation is possible by the rigid connection of a mobile robot and a task robot. Use a five joint articulated robot as the task robot; designed the 3 joint mobile robot for this usage. For a task execution assigned to the redundant robot, not only the task robot but the mobile robot should work in the coordinated way. therefore, a kinematic connection of the two robots should be cleary represented in a frame. And, also the dynamic interaction between the two robots needs to be analyzed. Clarified these issues considering the control of the redundant robot. Finally, demonstrate away of utilization of the redundancy as the cooperation between the mobile robot and the task robot to execute a common task.