• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.100-104
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• 2010

In the past decade, various search engines have been developed to retrieve web pages that web surfers want to find from world wide web. In search engines, one of the most important functions is to evaluate and rank web pages for a given web surfer query. The prior algorithms using hyperlink information like PageRank incur the problem of 'topic drift'. To solve the problem, relevance propagation models have been proposed. However, these models suffer from serious performance degradation, and thus cannot be employed in real search engines. In this paper, we propose a new ranking algorithm that alleviates the topic drift problem and also provides efficient performance. Through a variety of experiments, we verify the superiority of the proposed algorithm over prior ones.

• Journal of the Korean Society for information Management
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• v.16 no.2
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• pp.105-134
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• 1999

For efficient and precise searches in the Web environment, resources should be coded in a structured way. HTML does not cover semantic structure because of its fixed tagging. XML, which has emerged as an alternative standard markuplanguage, uses custom tags that allow structural searching. Therefore, this study aims to compare XML with HTML in terms of their characteristics and retrieval functions. In order to test retrieval functions of XML- and HTML-based systems, we constructed an experimental XML-based system. The XML-based system has several advantages over the HTML system. However, some improvements are needed to make the XML system more comprehensive and effective. First, XML document search engines with user-friendly interfaces are needed. Second, popular Web browsers such as Explorer and Communicator need to support XML 1.0 specification completely. Third, Open DTD format, which will allow information retrieval systems to retrieve documents and compress them into one single format, is also needed to control Web documents more efficiently.

• Journal of Korean Academy of Nursing Administration
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• v.16 no.4
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• pp.475-487
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• 2010

연구목적: 노인을 위한 건강정보 웹사이트들이 사용성과 접근성을 높이기 위해 지켜야 할 디자인 요소를 어떻게 반영하고 있는지 평가·비교함으로써 개선 방향을 제언하고자 하였다. 연구방법: 국내 및 미국에서 개발된 노인 대상의 건강정보 웹사이트를 각각 9개씩 선정하였다. 근거 기반의 웹디자인 지침서인 Make Your Website Senior Friendly: Checklist와 Research-based Web Design & Usability Guideline을 통합 수정하여 얻은 4개 영역의 평가 항목 48개를 적용해 두 명의 평가자가 선정된 총 18개 웹사이트를 평가하였다. 연구결과: '가독성' 영역 중 서체 선택, 줄 간격, 배경색과 글자색 선택 등은 양호하였으나 국내 웹사이트들 중에는 글자 크기가 조절되지 않는 경우가 빈번하였다. '정보의 표현과 구성' 영역에서 다수의 웹사이트들은 정보 배치 등이 우수하고 소비자 용어를 사용하는 노력을 보였다. 그러나 일부 국내 웹사이트들은 프린트 기능을 제공하지 않거나, 노인들의 저하된 인지 능력을 배려하려는 노력이 부족하였다. '미디어 사용' 영역에서 국내 웹사이트들은 글자 외에 다른 매체를 사용하는 빈도가 미국 웹사이트들에 비해 낮았고, 시청각 매체를 사용할 때는 동일한 내용을 문자로도 볼 수 있도록 하라는 권고안을 준수하지 않았다. '내비게이션과 검색의 용이성'에서는 메뉴나 링크의 명칭이 명확하며, 이용 중에도 쉽게 홈페이지로 돌아갈 수 있도록 구성되었다. 그러나 다수의 국내 사이트들이 사이트맵을 제공하지 않거나, 검색어의 철자오류 등에 대한 배려가 부족하였다. 결론: 국내 웹사이트들은 미국 웹사이트들에 비해 노인들의 사용성과 접근성을 높이는 것으로 밝혀진 연구 근거들을 제대로 반영하지 못하고 있었다. 노인 대상의 인터넷과 웹을 활용한 교육이 지속적으로 증가할 것이므로, 그 효과성을 높이기 위해 간호사들은 정보의 질 뿐만 아니라 디자인 측면의 중요성을 인식하고 실천할 수 있어야겠다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.2
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• pp.9-16
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• 2012

In this paper, the beamforming and user scheduling scheme for device-to-device (D2D) underlaying celullar networks with partial channel state information is investigated. In the proposed scheme, cellular users whose channels are nearly orthogonal to the channel between base station and D2D receiver are selected for unitary beamforming so as to minimize the interference to the D2D receiver. The interference caused by underlaying D2D communication can be minimized by reducing the D2D transmitter's transmission power. To enhance the cellular users' throughput further, we also investigate codebook generation method in which each code vector belongs to multiple unitary code matrices. From simulation results, we show that the proposed beamforming and user scheduling scheme mitigates D2D interference to the cellular networks and the codebook generation method improves cellular users' throughput.

• Convergence Security Journal
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• v.17 no.4
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• pp.11-16
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• 2017

MANET composed of only mobile node is applied to various environments because of its advantage which can construct network quickly in emergency situation. However, many routing vulnerabilities are exposed due to the dynamic topology and link failures by the movement of nodes. It can significantly degrade network performance. In this paper, we propose a secure routing protocol based on trust model. The domain-based network structure is used for efficient trust evaluation and management of nodes in the proposed technique. The reliability evaluation of nodes was performed by the discard ratio of control packet and data packet of the nodes. The abnormal nodes are detected by performing traffic check and inspecting of nodes on a path that generates excessive traffic in order to increase the efficiency of routing. It is confirmed through experiments of the proposed technique that data transmission is performed securely even if an attack exists on the path.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.799-808
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• 2005

This paper proposes low latency handover procedure for seamless connectivity and QoS support between wired (e.g. Ethernet) and wireless (e.g. WLAN, WiBro(802.16-compatible), CDMA) networks by the mobile-assisted and server-initiated handover strategy. It is assumed that the server decides the best target network considering network status and user preferences. In this algorithm a mobile terminal associates with the wireless link decided at the server In advance and receives CoA as well. When handover occurs without the prediction in wired networks, the server performs fast binding update using physical handover trigger through the MIH(media independent handover) function. As a result, a mobile terminal does not need to perform L2 and L3 handover during handover so that this procedure decreases handover latency and loss.

• Journal of Animal Environmental Science
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• v.16 no.2
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• pp.123-128
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• 2010

It is investigated the development of swine liquid manure spreading system for a polyethylene film (PE vinyl) based greenhouse used for planting vegetables. These types of vinylhouses are normally six to eight meters wide; the spread system must be contained and capable of operating within this area. The system we designed for use here consisted of the following parts: 1) a reel for loading the hose, 2) hydraulic motor and cylinder to generate hydraulic pressure, 3) discharge unit, and 4) a frame with a 3-point hiteh link to the tractor. With this system, there are two types of hoses that can be used, a flexible flat hose that can be mounted directly to a tractor or a solid firm round hose which usually separated from the tractor. In either case, the discharge unit remains on the tractor. It is found that by using our spread system overall efficiency was 5 times greater than spreading swine liquid manure manually.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1B
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• pp.16-23
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• 2009

This paper investigates how many optimal routes can be established in terms of a given wireless mesh routing metric. Although many of routing metrics have been devised to precisely derive the wireless link quality in mesh, most (if not all) metrics have not been evaluated their optimality along with routing protocols. We consider stateof-the-art routing metrics and a widely accepted routing protocol in order to observe the optimality of established routes varying the number of source nodes. Also, we propose a unidirectional routing to deal with possible link asymmetry feature in wireless links. Through comparative simulation evaluations, we show that the portion of optimally established routes becomes less as the network traffic load increases, regardless of employed metrics, network topologies, and routing protocols.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.116-130
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• 2012

This study focuses on analyzing the design industry in creative industry in the context of upbringing growth engine of regional development policy and strategy. This research probe the spatial characteristics and inter-organizational network structure change from 2000 to 2010 using social network analysis(SNA) in terms of structural, spatial and temporal aspects. first, with the statistical data of design industry, this research evaluate spatial distribution and agggglomeration compared with 16 cities and 7metropolitan scales in Korea. Next, the group of density in the knowledge network of design industry explained with the spatial characteristics and inter-organizational network evolution in time series. After considering the government policy and strategy providing as a result of establishing regional innovation center strengthen cooperation among industry-university-research center.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.45-52
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• 2005

This paper proposes low latency handover procedure for seamless connectivity and QoS support between wired (e.g. Ethernet) and wireless (e.g. WLAN, WiBro(802.16-compatible), CDMA) networks by the mobile-assisted and server-initiated handover strategy. It is assumed that the server decides the best target network considering network status and user preferences. In this procedure, a mobile terminal associates with the wireless link decided at the server in advance and receives CoA as well. When handover occurs without the prediction in wired networks, the server performs fast binding update using physical handover trigger through the MIH (media independent handover) function. As a result, a mobile terminal does not need to perform L2 and L3 handover during handover so that this procedure decreases handover latency and loss.