• 한국컴퓨터정보학회논문지
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• 제14권9호
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• pp.75-84
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• 2009

본 논문에서는 EPC Network의 응용 기술 분야에서 가장 중요한 기술로 연구되고 주목받고 있는 RFID를 활용하여 특수질병 감염환자를 효율적으로 관리할 수 있는 U-MAS (U-Medical Administrative Services)시스템을 설계하였다. U-MAS시스템은 질병관리본부에서 질병의 유형에 따라 감염환자들을 격리 수용과 치료, 회복, 퇴원, 격리병동 이탈 등을 집중 관리할 수 있도록 효율성을 증대시킬 수 있으며, 수작업과 단순한 컴퓨터 프로그램을 이용하는 현 수준의 질적 향상을 높이기 위해 RFID 태그를 이용하여 환자의 관리를 좀 더 면밀하고, 격리병동을 벗어나게 될 경우 관할 질병관리지역구에서 보다 빠르게 위치추적 등의 대응을 원활히 할 수 있도록 기여하는데 목적이 있다. 먼저, EPC 네트워크의 관련 기술과 모바일 RFID 시스템에 대한 관련 연구를 기술하고, U-MAS 시스템 설계를 제안한다. 제안된 U-MAS 시스템을 활용할 경우 전염성 질병환자에 대한 모니터링과 격리병동에 있는 환자가 무단으로 이탈하였을 때 위치추적에 소요되는 시간을 단축시키는 질병관리업무의 효율성을 개선할 수 있는 기대 효과를 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.91-107
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• 2014

Device-to-device (D2D) communication is an excellent technology to improve the system capacity by sharing the spectrum resources of cellular networks. Multicast service is considered as an effective transmission mode for the future mobile social contact services. Therefore, multicast based on D2D technology can exactly improve the spectrum resource efficiency. How to apply D2D technology to support multicast service is a new issue. In this paper, a resource allocation scheme based on cognitive radio (CR) for D2D underlay multicast communication (CR-DUM) is proposed to improve system performance. In the cognitive cellular system, the D2D users as secondary users employing multicast service form a group and reuse the cellular resources to accomplish a multicast transmission. The proposed scheme includes two steps. First, a channel allocation rule aiming to reduce the interference from cellular networks to receivers in D2D multicast group is proposed. Next, to maximize the total system throughput under the condition of interference and noise impairment, we formulate an optimal transmission power allocation jointly for the cellular and D2D multicast communications. Based on the channel allocation, optimal power solution is in a closed form and achieved by searching from a finite set and the interference between cellular and D2D multicast communication is coordinated. The simulation results show that the proposed method can not only ensure the quality of services (QoS), but also improve the system throughput.

• 한국화재소방학회논문지
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• 제29권5호
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• pp.14-22
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• 2015

본 논문은 2015년에 발생된 의정부 공동주택화재와 같이 화재발생시 초기 피난실패로 안타까운 인명피해 발생을 최소화하기 위하여 피난성능향상을 위한 주소형 비상방송시스템의 필요성에 관한 연구이다. 특히, 현대 건축물과 같이 복잡한 내부구조에서 발생되는 화재피해를 최소화하기 위해서는 정확한 화재위치를 재실자에게 경보하여 초기 피난방향 오류방지를 통해 효율적인 피난이 가능한 적응성 있는 비상방송시스템의 도입이 필요하다. 이에 본 연구에서는 기 개발된 주소형 시스템을 이용한 주소형 비상방송시스템을 설계 제작하고, 기존 재래식 비상방송시스템과의 성능비교실험을 실시하여 피난성능향상을 위한 주소형 비상방송시스템의 필요성을 확인하였다. 실험결과 주소형 비상방송시스템이 재래식 비상방송시스템보다 축소모형 피난성능실험에서는 최대 30.3%, 복도 피난성능실험에서는 최대 54.6% 이상 피난완료시간이 단축시킬 수 있는 것을 확인할 수 있었다.

• 전기학회논문지
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• 제58권9호
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• pp.1651-1657
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• 2009

In this paper, restoration solution algorithm to improve reliability better than restoration system of DAS(Distribution Automation System) is proposed in IDMS(Intelligent Distribution Management System). A strategy of IDMS restoration system to improve reliability and efficiency is proposed by analysis restoration system in DAS. Restoration sequence algorithm, distributed restoration solution algorithm considering a characteristic and a suitable restoration solution algorithm in IDMS are proposed. In the case study, algorithms have testified with example distribution network by C language

• 한국시스템다이내믹스연구
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• 제10권1호
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• pp.33-60
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• 2009

This study explores the limitation in making a causal model through an existing case and proposes an alternative plan to improve a theoretical system of causation modeling. To make a dynamic and actual model, several principles are needed such as reality based analysis of system structures and dynamics, consistent expression of causations, conversion of numerical formulas to causal relations, classification and arrangement of variables by size of concept, etc. However, it is hard to find cases to apply these considerations from existing models in System Dynamics. Therefore, this study verifies errors of derived models from literatures and proposes principles and guides that should be considered to make a sound dynamic model on a causal map. It contributes to making an opportunity for exciting public opinion to improve theory about causal maps, yet it has limitation that the study does not advance forward to the experimental step. For future study, it plans to make up by classifying and leveling causal variables, developing a dynamic BSC model.

• 전기학회논문지
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• 제66권3호
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• pp.486-492
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• 2017

In recent years, renewable energy sources have been mentioned as solution to environmental regulation and energy supply-demand. Energy storage systems are needed to mitigate the intermittent output characteristics of renewable energy sources and to operate micro grid efficiently using renewable energy generation systems. However, despite the necessity of energy storage system, this cannot secure the economical efficiency of the energy storage system by high initial cost. In this paper, a micro grid is constructed to supply electric power to industrial customers by using solar power generation system and energy storage system among renewable energy generation power sources and operated to improve energy independence. In the case study, we use photovoltaic system which is representative renewable energy generation system. Unlike conventional photovoltaic system, this system uses floating photovoltaic system with the advantage of having high output and no land area limitations. It is operated for the purpose of improving energy independence in the micro grid. In order to secure economical efficiency, the energy storage system operates a micro grid with a minimum capacity. Finally, this paper calculates the appropriate subsidy for the energy storage capacity.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (B)
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• pp.238-240
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• 2002

If there is an Information Retrieval system which comprehends the semantic content of documents and knows the preference of users. the system can search the information better on the Internet, or improve the IR performance. Therefore we propose the IR model which combines semantic based indexing and fuzzy relevance model. In addition to the statistical approach, we chose the semantic approach in indexing, lexical chains, because we assume it would improve the performance of the index term extraction. Furthermore, we combined the semantic based indexing with the fuzzy model, which finds out the exact relevance of the user preference and index terms. The proposed system works as follows: First, the presented system indexes documents by the efficient index term extraction method using lexical chains. And then, if a user tends to retrieve the information from the indexed document collection, the extended IR model calculates and ranks the relevance of user query. user preference and index terms by some metrics. When we experimented each module, semantic based indexing and extended fuzzy model. it gave noticeable results. The combination of these modules is expected to improve the information retrieval performance.

• 한국철도학회논문집
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• 제9권6호
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• pp.739-745
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• 2006

The role of maintenance in railway is going to be extended to improve the reliability of railway system in the aspect of Asset management gradually. In this paper, the meaning of reliability and safety in RCM which has been applied in order to improve the efficiency of maintenance is deduced. And the analysis task of reliability and safely which has been recommended in railway standards such as EN50126 and IEC62278 is reviewed in the aspect of RCM. Finally, the several ways are proposed to apply RCM to railway system through the comparison between the RCM procedure and the analysis procedure for the reliability and safety in railway standards. Hereafter, if the analysis of reliability and safety is performed with the concept of RCM in the beginning of railway business, it will be more efficient to improve the reliability and manage the railway asset.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.277-280
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• 2003

In this paper, we analyze the performance of transmitter and receiver of W-CDMA system using the channel coding and space time code in downlink over ITU-R realistic channel model. We can improve the reliability of communications and increase the data rate by channel coding, and we can get a diversity gain by using the space time code over fading channels. We also apply the RAKE receiver to improve tile performance in multi-Path fading channel environment.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.3-8
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• 2003

Platforms of many railroad stations are crowded with passengers regardless of the time throughout day. But the intensity of illumination of the existing lightening systems are so low enough to make passengers feel inconvenience in using platforms. Consequently there exists high possibility of accidents in platforms of low illumination. Hence, for the safety and convenience of passengers, it is necessary to improve the luminous intensity of lightening system for platforms. This paper points out the problems of existing system and presents the method to improve it.