• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 춘계 종합학술대회 논문집
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• pp.323-329
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• 2004

다기능 단말기 보급이 확산됨에 따라 무선인터넷 사업에서 이를 기반으로 새로운 사업모델이 개발되고 있다. 다기능 단말기는 VOD, AOD 등의 멀티미디어 서비스와 블루투스, 무선랜을 이용한 근거리 무선인터넷 서비스를 가능하게 하고 있다. 새로운 사업모델로 다기능 단말기를 이용한 홈 네트워킹 서비스가 개발되고 있다. 본 논문은 흠 네트워크 제어기와 연동하는 WIPI 기반 홈 네트워크 어플리케이션에 관한 것이다. 개발된 홈 네트워크 어플리케이션은 댁내 장비를 제어하고 웹 카메라와 연동하여 댁내의 보안상태를 확인할 수 있는 기능을 제공한다. GigBee, RFID 등의 PAN장치를 내장한 다기능 단말기가 개발됨에 따라 PAN을 이용한 다양한 서비스가 개발될 것이다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.188-192
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• 1997

The purpose of this study are changing wired medical instrument's terminal into wireless and implementing BSS of Wireless Local Area Network. the wireless terminal using frequency hopping spread spectrum in ISM band transfers patients medical information data such as ECG data, Patient Disease Indication Message to AP(or Server) and it also performs that as a response of transmission request in server. we made Clinet-Server network structure support only BSS service and patient's terminal controlled by polling in server. Wireless Terminal will guarantee mobility and give doctors real time monitoring capability in office.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.67-70
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• 1997

This Paper describes the system configuration and implementation method of an IMPRES (Interactive Multimedia exPRESS) terminal. The terminal is developed in the form of a PC add-on board that is called MINIBA (Media and Network Interface Board Assembly). IMPRESS is a communication service platform that support various interactive multimedia services. The main objectives of developing IMPRESS are to implement DAVIC compliant services platform to verify DAVIC specification and to support testing environment. Currently IMPRESS terminal provides MPEG-2 quality movies on demand, switched video broadcasting, and home-shopping service to the service user, based on the ATM network.

• ETRI Journal
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• 제28권3호
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• pp.311-319
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• 2006

This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

• 대한전자공학회논문지
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• 제13권6호
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• pp.20-23
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• 1976

본논문에서는 통신회로망의 신뢰도를 계산하는데 부울대수를 이용하는 방법을 제시하였다. 한 회로의 두 접합점사이의 모든 단순통로가 주어지면 병렬연산이라고 명명되는 부울대수산법에 의하여 두 단점사이의 신뢰도가 기호적으로 계산된다. 이 방법은 회로가 방향성이거나 비방향성이거나 다 효과적이다. A boolean algebra method for computing the reliability in a communication network is prosented. Given the set of all simple paths between two nodes in a network, the terminal reliability can be symbolically computed by the Boolean operation which is named parallel operation. The method seems to be promising for both oriented and nonoriented network.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.1027-1030
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• 2005

본 논문에서는 공중 무선망과 비인가 무선망과 같은 다양한 무선 네트워크가 존재하는 USN(Ubiquitous Sensor Network) 환경에서 사용자의 복잡한 설정이나 조작 없이 무선 네트워크에 접속할 수 있게 해주는 인터페이스로서의 적응형 무선 단말(Adaptive Mobile Terminal)의 개발 동향을 분석하였다. 이러한 적응형 무선 단말은 사용자의 이동이나 무선 자원의 변동 상황에 따라 능동적으로 사용자에게 끊김 없는 서비스를 제공할 수 있어야 한다. 따라서 적응형 이동 단말은 접속 가능한 무선 네트워크별로 독립적인 하드웨어 구조를 가져야 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1344-1367
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• 2014

Mobile traffic is increasing a masse because of the propagation of the Internet and the development of wireless mobile technology. Accordingly, the Network Local Mobility Management (NETLMM) working group [1] of the Internet Engineering Task Force (IETF) has standardized Proxy Mobile IPv6 (PMIPv6) [2] as a protocol for accomplishing the transmissibility of mobile terminals. PMIPv6 is a network-led IP-based mobility management protocol, which can control terminal mobility without depending on the type of access system or the capability of the terminal. By combining PMIPv6 and the mobility of Session Initiation Protocol (SIP), we can establish terminal mobility and session mobility through a more effective route. The mobility function can be improved and the overlap of function reduced as compared to that in the case of independent operation. PMIPv6 is appropriate for a non-real-time service using TCP, and SIP is appropriate for a real-time service using RTP/UDP. Thus, in the case of a terminal using both services, an effective mobility management is possible only by using PMIPv6 together with SIP. In order to manage mobility in this manner, researches on PMIPv6-SIP are in progress. In line with this trend, this paper suggests a new PMIPv6-SIP architecture where when a mobile terminal conducts a handover, a network-led handover while maintaining the session without the addition of a special function or middleware is possible along with effective performance evaluation through mathematical modeling by comparing the delay and the packet loss that occur during the handover to the Pure-SIP.

• 제어로봇시스템학회논문지
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• 제13권12호
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• pp.1252-1256
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• 2007

U-learning (ubiquitous learning) systems, which deliver learning materials anytime and anywhere, allow learners to watch live lectures on PDAs, tablet PCs and notebook computers via broadband and wireless Internet. These systems have various problems; first, terminal devices are expensive, and it is difficult to maintain their efficiencies. Secondly, Internet does not guarantee quality of service (QoS), and in general it does not provide real-time services. Finally, the security of these systems is weaker in a local network than in an external network. The USB-based terminal system based on the OSGi service platform was designed as a ubiquitous system, in order to solve those problems. The USB terminals, used in this system, are inexpensive, and it is easy to maintain their performances. Also, this system solves the problems of security in a local network and provides guaranteed QoS. To accomplish this, the number of USB terminals connected to the system has to be limited according to the formula proposed in our paper. This system uses the OSGi specification as a middleware. It supports the discovery mechanism of the USB terminals, maintenance and administration of the system. Finally, this paper shows a driver's license testing system as an example u-learning application1.

• Journal of information and communication convergence engineering
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• 제19권2호
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• pp.114-119
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• 2021

This paper proposes a method to find an optimal T' with the most terminal of the subset of T' trees that can be connected by a given length by improving a memetic genetic algorithm within several constraints, when the set of terminal T is given to the Euclidean plane R². Constraint (1) is that a given length cannot connect all terminals of T, and (2) considers only the rectilinear layout of the edge connecting each terminal. The construction of interconnections has been used in various design-related areas, from network to architecture. Among these areas, there are cases where only the rectilinear layout is considered, such as wiring paths in the computer network and VLSI design, network design, and circuit connection length estimation in standard cell deployment. Therefore, the heuristics proposed in this paper are expected to provide various cost savings in the rectilinear layout.

• Journal of Power Electronics
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• 제18권2호
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• pp.467-481
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• 2018

Modular multilevel converter (MMC)-based high-voltage direct current (HVDC) presents attractive technical advantages and contributes to enhanced system operation and reduced oscillation damping in dynamic MMC-HVDC systems. We propose an advanced small-signal multi-terminal MMC-HVDC based on dynamic phasors and state space for power system stability analysis to enhance computational accuracy and reduce simulation time. In accordance with active and passive network control strategies for multi-terminal MMC-HVDC, the matchable small-signal stability models containing high harmonics and dynamics of internal variables are conducted, and a related theoretical derivation is carried out. The proposed advanced small-signal model is then compared with electromagnetic-transient and traditional small-signal state-space models by adopting a typical multi-terminal MMC-HVDC network with offshore wind generation. Simulation indicates that the advanced small-signal model can successfully follow the electromechanical transient response with small errors and can predict the damped oscillations. The validity and applicability of the proposed model are effectively confirmed.