• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1196-1203
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• 2013

In general, the cost of transceiver for wireless network configuration is more expensive than that for wired network. However, in case of environmental management system in a tunnel, the cost can be minimized by adopting low rate tranceiver because the amount of the exchanged data for tunnel monitoring is very small. When the obtained data from sensor node is sent directly to the corresponding command node, there is no need to consider routing problem of the data transfer. However in this case, sensor nodes are required to be implemented with high power transmitter and experience high energy consumption. To tackle this problem, relay nodes can be used to transfer the data of tunnel monitoring, and suitable routing protocols for selecting optimum path are needed. Therefore, in this paper, we propose a routing algorithm and a self-configuration protocol for environment management system in tunnel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.783-788
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• 2016

An LTE enhancement for licensed-assisted access (LAA) to unlicensed spectrum has been studied recently and the first version of its design has been released in early 2016. As both 2.4 and 5GHz ISM bands have multiple channels and Wi-Fi devices already support multi-channel operation, LTE LAA has also been designed such that an eNB can access multiple channels at the same time. In this paper, we review several design variants of listen before talk (LBT) procedure for multi-channel transmission in downlink and perform simulation to investigate coexistence of Wi-Fi and LAA as well as the performance of both.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.393-398
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• 2007

본 논문은 작업 현장에서 청각장애인의 의사소통을 보조하는 한국 수화 메시지 보드의 개발에 대하여 다룬다. 청각 장애인은 일상적인 직업 현장에서 의사소통이 자유롭지 못하여 업무에 잘 적응하지 못하고 사내의 인간관계에 많은 어려움을 겪고 있다. 문자를 이용한 정보 전달을 통해 모든 의사소통을 대체할 수 있을 것이라는 일반적인 생각과는 달리, 청각장애인의 경우 비장애인과 비교하여 사물의 개념 습득에 어려움이 있을 수 있으며 마찬가지로 사용하는 어휘수도 제한적인 경우가 많아 문자를 통한 의사소통에는 명확한 한계가 존재한다. 실제로 청각 장애 근로자가 이직하는 사유로 의사소통이나 인간관계가 높은 비중을 차지한다. 수화 메시지 보드는 크게 사내 네트워크를 이용한 공지 사항 전달을 위한 용도와 복수 개의 메시지 보드 간 문자 송수신의 용도로 사용 가능하다. 비장애인이 청각장애인에게 문자 입력으로 의사를 전달하면, 전달된 문자는 문자-수화 번역기를 통해 자동으로 수화로 번역되어 아바타의 수화 동작으로 화면에 출력된다. 전체 시스템은 수화 아바타를 포함한 그래픽 유저 인터페이스 (GUI), 수화 데이터베이스 및 한글 형태소/문장 분석기를 포함하는 문자-수화 번역기, 그리고 TCP/IP 기반의 문자 전송기의 세 부분으로 나뉜다. 본 논문에서는 수화 데이터베이스의 단어 선정을 위한 대상 작업 현장을 청각 장애 근로자가 타 직업에 비해 많은 비중을 차지하는 전자 부품 조립 업체로 한정하였다. 수화 데이터베이스는 자음 14종, 모음 17종, 숫자 15종, 일상생활 용어 1000종, 전자 부품 조립 업체에 특화된 단어 50종 및 직업 교육 관련 용어 50종으로 이루어진 총 1146종의 수화 단어를 포함하며, 수화 데이터베이스에 등록되지 않은 단어에 대해서는 지화로 표현하도록 한다. 이 중 전자 부품 조립 업체 특화 단어와 관련하여서는, 현재 동일한 분야의 작업 현장이라 하더라도 각 사업장 간 사용되는 수화가 통일되지 않아 문헌 조사 및 현장 조사를 통해 사용 빈도가 높고 형태가 공통적인 50종을 추려내었다. 본 연구는 실제 업무현장에서 청각장애인이 겪는 의사소통의 문제를 효과적으로 해결함으로써, 청각장애인이 직업 현장에 보다 쉽게 적응하도록 도움을 줄 뿐만 아니라, 일을 통해 자아 실현을 하도록 돕는 방안이 될 수 있다는 점에서 중요한 의의를 갖는다.

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.1100-1110
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• 2003

Design and implementation of remote procedure cail (RPC) resource service system based on the XML considering the request delegation between the servers are described for the resource application and efficient processing of distributed environment. For this purpose, the request information about several server, which would be used by client, is encoded into XML document based on XML-DOM and transferred to server. Server classifies the client requests using objects which can deal with the XMLL-DOM. For the request delegation between the servers, server saves the request result of client in XMLL-DOM structure without replying it immediately, and makes the client request delegated to another server in XML-DOM's request information. In addition, the resource repository are managed for resource transparency of distributed environment. As a result, resource application and processing efficiency are improved by reduction of response time caused by integration of RPC and XML-RPC services and request delegation between the servers. Extension of asynchronous and average blocking time of client were reduced and information of resource which can be used by client was offered.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.907-916
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• 2005

RMCP is an application layer multicast protocol and was established as a standard by ITU-T Also, RMCP includes a scheme which can statically construct a multicast tree. In this paper, we propose a QoS based tree construction scheme which can dynamically construct a multicast tree. And this scheme shows more superior performance than the static tree scheme of RMCP in terms of start-up delay and user requirement QoS. This scheme consists of a best-fit method using multiple sub-net groups which are satisfied a user requirement QoS and a first-fit method using one sub-net group which has maximum transmission bandwidth. In simulation result, two proposed methods are superior to the existing static tree scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.111-119
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• 2010

With the rapid progress of wireless technologies today, mobile terminals with multiple access interfaces are emerging. In recent years, WLAN (Wireless Local Area Networks) has become the premier choice for many homes and enterprises. WiMAX (Worldwide Interoperability for Microwave Access) has also emerged as the wireless standard that aims to deliver data over long distances. Therefore, it is important to explore efficient integration methods for delivering multimedia data between heterogeneous wireless networks. In this paper, we developed the simulation models and environments for the mobile multihomed node that has both WiMAX and WLAN interfaces and can move around in both networks by using mobile IP. In order to verify the developed models, we designed and constructed several simulation scenarios, e.g. movement in WiMAX/WLAN, group mobility, MANET, and nested MIP under the various traffic environments such as oneway or bothway UDP packets, FTP traffic, and voice with SIP protocol. The simulation results show that the developed models are useful for mobility studies in various integrated wireless networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1A
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• pp.50-57
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• 2009

Tag collection is one of the major functions in RFID systems. In this paper, we propose a multichannel slotted-aloha anticollision protocol to mitigate the tag collision problem and improve tag collection performance in active RFID systems. In the proposed anticollision protocol, while an RFID reader transmits commands to multiple RFID tags via a common channel, it receives multiple tag responses over multiple channels simultaneously. We also implemented an active RFID system supporting the proposed anticollision protocol. In experiments with the implemented reader and 60 tags, the proposed dual-channel slotted-aloha anticollision protocol showed a large improvement in tag collection performance compared with the single-channel slotted-aloha anticollision protocol. With 60 tags, the average time spent on tag collection using the dual-channel anticollision protocol was 600.543 ms, which was 46.3% of the 1289.721 ms required using the single-channel anticollision protocol.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.467-467
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• 2017

토양수분 및 황사발생 연구에 있어 효율적인 광역 분석을 위하여 위성자료가 활용되고 있다. 활용 시나리오에 따라서는 준실시간 자료 수신, 처리가 필요하며 본 연구에서는 이에 대한 방안을 연구하기 위하여 유럽 EUMETSAT(European Organisation for the Exploitation of Meteorological Satellites)의 ASCAT(Advanced Scatterometer) Metop-A 자료에 대하여 파악하였다. 자료 수신 프로토콜에 있어서 FTP, HTTP 등 전통적 방법에 대한 현황과 함께 비교적 최근 기법인 OGC(Open Geospatial Consortium)　 WMS(Web Map Service), WCS(Web Coverage Service) 방식의 지원 현황에 대하여 확인하였다. 제공되는 자료 Format부분은 EPS Native와 BUFR(Binary Universal Form for the Representation of meteorological data)을 살펴보되 데이터 프로바이더 측에서 대부분 채택되고 있는 NetCDF(network Common Data Form)를 중심으로 파악하였다. 수신된 자료의 처리 자동화를 위한 소프트웨어는 OSGeo(The Open Source Geospatial Foundation)의 GDAL(Geospatial Data Abstraction Library), 미국 NCAR(National Center for Atmospheric Research)의 NCL(NCAR Command Language)을 중심으로 확인하였다. 자료 가공기법은 격자(Raster) 자료에 대한 기본 메타정보 확인, 좌표참조체계 변환, 해상도 및 Format 변환을 중심으로 확인하였다. 한편 OGC WMS, WCS는 자료의 전송 프로토콜 기법이면서 동시에 서버 사이드에서의 자료 변환 기능을 구비하고 있다. 예를 들어 Http Request에서 영역(Extent), Format 형식, 좌표참조체계를 지정할 수 있다. OGC WMS에 대한 EUMETSAT 파일럿 서비스에서 반환 자료의 공간적 영역, 복수 시점 제공 현황, 반환 포맷 지원 상황은 실제 메서드를 사용하여 파악하였고, 향후 발전 방향을 전망하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.234-239
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• 2021

Recently, as the installation of a large number of high-performance CCTVs for crime prevention and traffic control has increased rapidly, the problem of increasing system requirements for response to privacy infringement factors and analysis of high-definition image information transmitted from multiple cameras has been actively emerging. Accordingly, there is a need for a method for responding to privacy infringement and a method for efficiently processing surveillance images input from multiple cameras. In this paper, in order to reduce the processing cost of the input image and improve the processing speed, an integrated image is generated by grouping images input from a plurality of cameras. After analyzing the pre-generated integrated video, it detects a preset privacy event or an event that highlights interest. Depending on whether or not an event is detected, you will perform an editing operation corresponding to the event.

• Convergence Security Journal
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• v.22 no.4
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• pp.119-127
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• 2022

A movie information program has a positive effect on the viewer's intention to watch the movie by providing an indirect experience of the movie based on trust. In order to increase the effectiveness of a movie information program, a data service that provides the additional information on the movies introduced in a movie information program has been studied. However, since the study limited the data service to one movie information program, it was difficult to apply it to the actual environment of general cable broadcasting companies or satellite broadcasting companies that transmit multiple movie information programs. Therefore, this study expanded the existing research limited to one movie information program to provide additional information of several movie information programs. This study is meaningful in that it suggests a data service that can be operated in the realistic environment of a broadcaster that actually transmits several movie information programs.