• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.78-87
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• 2021

This paper analyzes the range and attributes of the traffic information service between domestic public institutions and private companies, and suggests the possibility of joint application of node-link information for each company and the possibility of joint use of private traffic information. For this purpose, the present condition and attributes of domestic and foreign traffic information node-links (link length, node ID number, U-turn information, lane information, left turn information, right turn information, etc.) were analyzed. The analysis targets, the node-link of the national standard node and the two companies were analyzed. The area of the experiment was selected in Jongno-gu, Seoul, where standard-link information is complex, traffic volume is high, and various standard-links exist. The experiment was conducted by comparing and analyzing the traffic information attributes of three types of node-links and performing node-links overlapping matching (utilizing encoding_decoding method), and the possibility of matching node-links and attributes of different specifications was analyzed using Open LR technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.393-400
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• 2013

In conventional single-tier networks, downlink based association is the best association scheme for the uplink association because all macro base stations have the same physical specification. However, in uplink heterogeneous cellular networks, a downlink based cell association cannot be the best for uplink any more because of the difference of physical specification between the different base station. In this paper, we will propose a uplink based cell association scheme, and devise performance metric for describing a uplink performance in heterogeneous cellular networks. Then, we will discuss the necessity of the uplink based association by observing outage probability, delay constraint outage probability, delay constraint outage capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.553-558
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• 2009

There have been various research efforts to support the fairness between uplink and downlink of TCP streams in IEEE 802.11 networks. Existing methods, which have been effective for the fairness, however could not provide the solution for the unfairness caused by the situation in which a station which is having multiple TCP uplink streams monopolizes the uplink bandwidth. This paper proposes a method that AP allocates token buckets for each uplink TCP station. The proposed method is also able to support the fairness between the uplink and downlink. To remedy the underutilization which may happen under token bucket-based schemes, it allows the movement of redundant tokens among the token buckets. By controlling the token movements, it can balance the fairness and the utilization. Simulation results show that the proposed method is able to support the fairness of the TCP uplink stations, as well as the fairness between the uplink and downlink.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.483-494
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• 2001

Most of hypertext retrieval models consider documents as independent entities. They ignore relationships between documents of link semantics. in an information retrieval system for hypertext documents, retrieval effectiveness can be improved when ling information is used. Previous link-based hypertext retrieval models ignore link information while indexing. They utilize link information to re-rank the retrieval results. Therefore they are limited that only the documents is result-set utilize link information. This paper utilizes link information when indexing. We present how to use term weighting and inLinks weighting for ranking the relevant documents. Experimental results show that recall and precision evaluation according to the link semantics and the comparison with previously link_based hypertext retrieval model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.68-77
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• 2010

Wireless sensor networks are installed in various environments and collect sensing data through wireless links. The quality of a wireless link may be unstable due to environment causes and hardware performance in wireless sensor networks. Since the change of the link quality may cause data loss, sensor nodes need to adaptively estimate the change of the link quality. Also, the routing protocol should deal with this situation. In this paper, the adaptive link quality estimation and routing scheme in the large-scale wireless sensor networks are proposed. When the quality of a link is unstable, sensor nodes agilely estimate the quality of links, and the new route is selected. When quality of a link is stable, the link quality is occasionally estimated so that the energy consumption is reduced. Moreover, sensor nodes exchange less beacons in order to reduce an overhead in dense networks. In the case of sparse network, the sensor nodes exchange more beacons for finding a better route. We prove that the proposed scheme can improve the energy efficiency and reliability.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.17-23
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• 2016

It is essential to develop an estimation and cancellation algorithm for feedback signals in designing the interference cancellation systems (ICS) as a solution to extending the coverage of the TDD LTE networks. Unlike the radio access of FDD LTE networks, TDD networks utilize the same frequency band in downlink and uplink for radio access. For this reason, downlink and uplink are repeated in time and thus the estimation of the feedback signals in uplink and downlink, respectively, is periodically paused to cause performance degradation. In this study, the reciprocity of downlink and uplink is examined through experiments and exploiting the same frequency band in uplink and downlink, an efficient channel estimation and elimination algorithm is proposed since the algorithm utilizes the same structure for both downlink and uplink.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1465-1471
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• 2007

The electro-magnetic wave propagates through the air in the terrestrial communications, but the acoustic wave propagates through the seawater in the underwater acoustic communication(UAC). It makes the differences between the UAC link and the well hon air communication links. In this paper, we have studied path loss, absorption and ambient noise of the ocean as a medium for UAC. We have analyzed the absorption coefficient and ambient noise level of the coastal area of South Korea and suggested a strategy for the selection of the frequency band by considering the absorption coefficient and ambient noise level. Also, we present an illustrative example of a link budget for the QPSK UAC system which has carrier frequency 25kHz, bit rate 10kbps, range 1km and BER $10^{-3}$ in the shallow water environment with an ideal AWGN assumption.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.417-418
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• 2008

본 연구에서는 웹 서비스의 종류가 급격히 증가하게 됨에 따라 유사 패턴의 사용자들을 위해 웹 링크 서비스를 일부 추천해주는 시스템에 대해 설계 및 구현하였다. 본 연구를 통해 유사 패턴의 웹 서비스 이용자들의 그룹을 정의 하는데 네이브 베이지안 알고리즘을 적응하고 그에 따른 새로운 사용자에 대한 그룹정의도 함께 한다. 유사 패턴의 그룹의 사용자들에게 적합한 링크들을 추천해준다. 기존의 추천 시스템에서 제공하는 추천 아이템을 제정의 하는 것이 아니라 기존의 웹 서비스 페이지에서 유사 패턴의 그룹에게만 일부의 링크들만 활성화 하여 제공한다. 이는 웹 서비스의 일부 링크 서비스들만을 활성화 하여 추천 해줌으로써 웹 서비스의 모바일 디바이스등에 제공시 웹 페이지의 소스를 경감하여 좀 더 수월하게 서비스 할 수 있다. 또한 사용자들도 추천 받은 링크만을 접근하게 됨에 따라 접근하지 않는 다른 서비스에 대한 링크 소스가 빠진 웹 페이지만 제공 받을 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.371-374
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• 2008

현재 수많은 상업포탈 사이트들은 다양한 서비스를 제공하기 위해 많은 노력을 기울이고 있다. 다양한 서비스를 제공함으로써 다양한 소비자들을 더 수용하기 위해 다양한 기능들을 개발하고 있다. 이러한 기능들을 제공하기 위해 많은 양의 하이퍼링크로 연결된다. 이런 많은 양의 하이퍼링크들은 초기 서비스 웹 페이지 소스의 대부분을 차지하게 된다. 이는 웹 서버의 부하를 주는 것은 물론이고 사용자들 역시 그렇게 많은 링크 서비스를 필요로 하지 않기 때문에 많은 양의 링크들을 정리할 필요가 생긴다. 즉 사용자들이 빈도수가 높은 서비스에 대한 링크만을 연결함으로써 웹 서버의 부하를 줄이고 웹 페이지의 소스의 양도 크게 줄일 수 있다. 일반 웹 페이지의 소스를 렌더링하여 필요한 링크만 제공하는 구현을 통해 웹 서버의 성능 향상을 연구한다.

• Journal of Biosystems Engineering
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• v.7 no.2
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• pp.8-17
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• 1983

특수(特殊)한 기능(機能)을 수행(遂行)하기 위한 4링크 기구(機構)의 설계(設計)에서는 링크의 연간궤적(連稈軌跡)이 중요(重要)한 설계조건(設計條件)이 된다. 이앙기(移秧機)의 이식기구(移植機構)나 바인던의 방출(放出)암은 모두 4링크 기구(機構)를 이용(利用)하여 작업수행(作業遂行)에 필요(必要)한 연간궤적(連稈軌跡)을 얻고 있는 것이다. 필요(必要)한 연간궤적(連稈軌跡)을 얻기위한 4링크 기구(機構)의 합성(合成)은 도해적(圖解的), 해석적(解析的) 방법(方法)을 통(通)하여 많은 연구(硏究)가 이루어져 왔으며 최근(最近)에는 콤퓨터를 이용(利用)한 기구합성(機構合成)에 대(對)한 연구(硏究)가 활발하게 이루어지고 있다. 본(本) 연구(硏究)에서는 연간궤적상(連稈軌跡上)의 점(點)들을 이용(利用)하여 주어진 연간궤적(連稈軌跡)을 얻기 위한 4링크 기구(機構)의 합성(合成)에 대(對)한 새로운 방법(方法)을 개발(開發)하고 이 방법(方法)을 콤퓨터 프로그래밍하여 주어진 연간궤적(連稈軌跡)과 콤퓨터로 합성(合成)한 4링크 기구(機構)의 연간궤적(連稈軌跡)을 비교(比較)검토 하였다.