• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.440-450
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• 2003

The reverse link of a spectrally overlaid macrocell/microcell cellular CDMA system supporting multimedia traffic is characterized in terms of the required signal power, interference, and capacity. Several narrowband subsystems are overlaid with a wideband subsystem in macrocells, while a single wideband subsystem is operated in a microcell with the same spectrum as the macrocell wideband subsystem. Using a typical propagation model the reverse link signal power and interference are characterized as the relative user signal power and the cross-tier interference factors between the macrocell and the microcell. The reverse link capacity of the overlay system is then analyzed. Analytical results show that the dominant parameters affecting the system performance are the spectral overlay ratio and the distance between the microcell and macrocell base stations. In particular, when the distance equals a half of macrocell radius, optimum performance can be achieved by minimizing the cross-tier interference factors. These results can be applied to CDMA multimedia network planning in heavily populated traffic areas.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.101-105
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• 2018

이 논문은 가장 잘 알려진 어휘부중 하나인 워드넷의 활용 범위 확장을 위해 워드넷 신셋에 "사건구조 프레임(Event Structure Frame)"을 주석하는 연구에 관한 것이다. 워드넷을 비롯하여 현재 사용되고 있는 어휘부는 풍부한 어휘의미정보가 구조화되어 있지만, 사건구조에 관한 정보를 포함하고 있지는 않다. 이 연구의 가장 큰 기여는 워드넷에 사건구조 프레임을 추가함으로써 워드넷과의 연결만으로 핵심적인 어휘의미정보를 모두 추출할 수 있도록 해준다는 점이다. 예를 들어 텍스트 추론, 자연어처리, 멀티 모달 태스크 등은 어휘의미정보와 배경지식(상식)을 이용하여 태스크를 수행한다. 워드넷에 대한 사건구조 주석은 자동사건구조 주석 시스템인 GESL을 이용하여 워드넷 신셋에 있는 예문에 먼저 자동 주석을 하고, 오류에 대해 수동 수정을 하는 반자동 방식이다. 사전 정의된 23개의 사건구조 프레임에 따라 예문에 출현하는 타겟 동사를 분류하고, 해당 프레임과 매핑한다. 현재 이 연구는 시작 단계이며, 이 논문에서는 빈도 순위가 가장 높은 100개의 동사와 각 사건구조 프레임별 대표 동사를 포함하여 총 106개의 동사 레마에 대해 실험을 진행하였다. 그 동사들에 대한 전체 워드넷 신셋의 수는 1337개이다. 예문이 없어서 GESL이 적용될 수 없는 신셋을 제외하면 1112개 신셋이다. 이 신셋들에 대해 GESL을 적용한 결과 F-Measure는 73.5%이다. 향후 연구에서는 워드넷-사건구조 링크를 계속 업데이트하면서 딥러닝을 이용해 GESL 성능을 향상 할 수 있는 방법을 모색할 것이다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.105-111
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• 2012

In this paper, we investigate the most commonly adopted networking technology for Network Centric Warfar (NCW), namely Link-16 in the perspectives of physical, data link, and network layers (specifically, strategic message exchanges) and derive its merits with some constraints therein. Furthermore, we perform a quantitative evaluation on its communication capacity, focusing on whether Link-16 can indeed meet the capacity requirements for major operations, based on the time slot structure, NPG, and multi-netting concepts.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.797-804
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• 2002

As internet use is being generalized central of WWW(World Wide Web) service of multimedia based recently, we could acquire many informations that exist to all over the world's computer network .Therefore, picking up of information became important problem before that internet is generalized, but it is risen to important problem to acquire correct information rapidly on modem society that use of internet is generalized. This paper designed internet search engine and understand structure of internet search engine drawing URL that is optimized, and secure embodiment technology using Java that is language of object base. Search engine that proposed in this paper maintained user's the convenience by offer keyword search, and simplify user interface And although quantity of searched information site is few, search engine show that the bad link rate of searched result is improved compare with existent domestic manufacture search engines.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.878-883
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• 2006

New emerging wireless broadband internet can make many broadband multimedia services. The networked intelligent mobile robot service is one of the new services. In the networked robot control, both the on-line real-time control and the reliability of control data transmission are very important. Considering the real-time control and data reliability, an efficient transmission method based on UDP protocol is proposed. The proposed method allocates the priority to the robot control data and the transmission of the robot data at the base station is carried out in duplicate manner. NS-2 simulation results show that the proposed scheme has a very low packet delay and low packet errors.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.83-88
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• 2001

In this paper, System performance parameters such as throughput, blocking probability and delay have been analyzed and expressed as a function of demanding traffic and service terminating probability, and we centers our discussion at particular downlink port of satellite switch which is capable of switching the individual spot beam and processing the information signals in the packet satellite communications with demand assigned multiple access technique. Delay versa throughput as a function of traffic parameters with several service terminating probability can be derived via mathematical formulation and simulation and the relative change of transmission delay was compared.

• Information and Communications Magazine
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• v.22 no.9
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• pp.138-163
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• 2005

2세대 이동통신의 본격적인 상용화 이후, 보다 향상된 무선 멀티미디어 서비스를 지원하기 위해 ITU는 IMT-2000이라고 불리는 복수의 국제 무선 규격을 2000년에 승인하였으며 이을 통칭하여 3G(Third Generation) 이동통신 시스템이라고 부르고 있다. 특히 여러 3G 기술 표준들 가운데 3GPP(Third Generation Partnership Project)와 3GPP2(Third Generation Partnership Project)라는 양대 국제 표준화 기구에서 완성된 UMTS와 cdma20()0 @ 시스템은 현재 일본, 유럽, 미국, 국내 등지에서 본격적인 상용 서비스를 시행 또는 준비 중에 있다. 초기 3G 표준의 제정 이후, 각 표준화 기구들은 상향과 하향 링크의 양방향 모두에서의 고속 패킷 데이터 전송, 무선 성능 향상, IP 네트워크를 위한 구조의 진화, 향상된 서비스 등을 목표로 하여 3G 무선 규격에 대한 성능 향상 및 진화를 위한 표준화 작업을 진행해 왔으며 또한 현재에도 진행 중에 있다. 최근에 이르러3GPP에서는 장기적 관점에서 향후 시스템의 진화 (Long-Term Evolution: LTE) 방향에 대한 논의가 활발히 진행되고 있으며, 3GPP2 TSG-C에서도 진화 방향에 대한 논의가 구체화되기 시작하였다. 본 논문 에서는 3GPP/3GPP2 표준화 동향 및 각 표준화 단체의 최종 진화 시스템에 대한 다양한 방향성을 가늠해 본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7C
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• pp.435-442
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• 2011

The MIMO has weak points such as size and cost of systems and the complexity of hardware augment. Thus, the cooperative transmission techniques have been recently discussed briskly and it also solves problems by increase of shadowy area. However, limited cooperation scheme is utilized due to a single-antenna at the destination. The base station is simply equipped with multiple antennas. When the base station has multiple antennas, cooperative diversity and multiplexing schemes can be easily applied in the base station. To guarantee reliability with high throughput, a cooperative hybrid cyclic relay diversity transmission scheme is proposed which can use an arbitrary number of relays without rate loss and a modification of the base station. The presented results show that the proposed schemes can be effectively applied to the existing various MIMO-OFDM communication system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2A
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• pp.134-141
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• 2010

In this paper, we propose a scheduling algorithm to improve the performance of IEEE 802.16 based wireless mesh networks using directional antenna. The performance is presented in terms of throughput of system and delay between each node by varying number of users. The result show that proposed scheduling algorithm improving the performance by reducing the delay of mesh network system. Our work may be useful as a guideline to control the fairness between SSs for multi-hop systems such as multi-hop relay and mesh networks.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1090-1097
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• 1999

the multi computers operated in harsh environments should be designed to guarantee normal operations in the presence of the component faults. One solution for this is a fault-tolerant routing. In the paper, we consider n-dimensional meshed network for the basic topology and propose a simple fault-tolerant routing algorithm that can transfer messages to their destination as desired in the presence of some component faults. the built algorithms basically adopts a WormHole(WH) routing method and uses the virtual channels sharing a physical channel for deadlock-freedom. Consequently, we show that the suggested algorithm has a higher performance than the X-Y routing algorithm through simulation results.