• Journal of Communications and Networks
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• 제5권4호
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• pp.386-393
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• 2003

Future wireless networks are expected to achieve high bit rates at low cost, enabling multimedia and QoS-based services over the wireless medium. The impulse radio ultra-wide band (IR-UWB) technique is a promising candidate in the deployment of such networks, thanks to its potential robustness and capacity. In the past, most of the UWB research focused on hardware and physical layer aspects in order to solve the technological challenges posed by IR-UWB. UWB peculiar characteristics may, however, also stimulate innovative higher layers’ design. This work addresses MAC issues for UWB communication systems. Key areas such as medium sharing, MAC organization, packet scheduling and power control are reviewed. The impact of UWB on the above functions is discussed, and areas which require UWB specific design are identified. Finally, novel MAC functions enabled by UWB specific features, i.e., precise ranging and positioning, are presented.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1996년도 제10회 동계학술발표회 논문집
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• pp.141-153
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• 1996

Firms prefer in some specific conditions cooperative R&D to non-cooperative for developing technology. Previous studies on the conditions show firms want to choose cost-sharing type of cooperative R&D (the CS-RJV) rather than non-cooperative one when target technology is either 'relatively easy'or 'relatively difficult', and to join multiple-research type of cooperation (the MR-RJV) than to compete each other if technology is only 'relatively easy'. However, by introducing technological spillover as well as difficult of technology, only if there shown that this seemingly contrasted phenomenon almost disappears : the MR-RJV can i3e also preferred by firms even in case of 'relatively difficult'technology only if there exists some extent of a technological spillover.

• 한국인터넷방송통신학회논문지
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• 제10권6호
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• pp.77-84
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• 2010

본 논문은 이동 통신 네트워크에서 기지국과 집중국사이에 설치되어 전송 비용을 줄여줄 수 있는 RAN (Radio Access Network)전송 시스템을 구현하는 것이다. 이 시스템은 여러 세대의 이동 통신 기지국 개별적으로 사용하는 전송 링크를 공유함으로써 전송 링크 수를 감소시켜 줄 수 있고, 지연 시간에 민감하지 않은 트래픽을 분류하여 그 트래픽을 Ethernet/IP 네트워크를 통하여 전달해 줄 수 있다.

• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.712-720
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• 2011

Radio frequency identification (RFID) is an established technology and has the potential, in a variety of applications, to significantly reduce cost and improve performance. As RFID-enabled applications will fulfill similar tasks across a range of processes adapted to use the data gained from RFID tags, they can be considered as software products derived from a common infrastructure and assets that capture specific ions in the domain. This paper discusses a framework that supports the development of RFID-enabled applications based on a business process family model (BPFM), explicitly representing both commonalities and variabilities. To develop this framework, common activities are identified from RFID-enabled applications and the variabilities in the common activities are analyzed in detail using variation point concepts. Through this framework, RFID data is preprocessed, and thus, RFID-enabled applications can be developed without having to process RFID data. Sharing a common model and reusing assets to deploy recurrent services may be considered an advantage in terms of economic significance and the overall product quality afforded.

• 한국CDE학회논문집
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• 제17권2호
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• pp.132-139
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• 2012

Presented in the paper is a procedure to extract simplified triangular mesh from a height map (terrain data). The proposed algorithm works directly on a height map that extracts a simplified triangular mesh. For the simplification, the paper employs an iterative method of edge contractions. To determine an edge to be contracted, the contraction cost of an edge is evaluated through the QEM method. Normally, an edge contraction will remove two triangles sharing the edge. Although the edge contraction can be implemented easily on a triangular mesh, it is not viable to implement the operation on a height map due to the irregular topology. To handle the irregular topology during the simplification procedure, a new algorithm is introduced.

• Current Photovoltaic Research
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• 제8권3호
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• pp.79-85
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• 2020

The growing demand for new energy infrastructure has often been encountered with the difficulties of siting in power plants and electric transmission lines. Siting such large-scale and complex facilities produces so many-sided issues that it is highly necessary to develop an approach to resolving the related problems and conflicts. This paper introduces how the stakeholders have handled the issues and resolved conflicts with residents opposed the construction of 765 kV transmission line. The solar photovoltaic power generation, called "Hee-Mang Sunlight Power project", is used for persuading residents to agree with constructing high-voltage transmission line and sharing benefits. It is considered how the project performance such as generation output and resident's profits is and proposed what the project should be revised and supplement. The project is shown that the intractable spiting in energy systems can be smartly resolved with cost-effective institutional solutions instead of relatively expensive technical ones.

• 디지털융복합연구
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• 제6권4호
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• pp.83-90
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• 2008

When small organizations construct and operate Knowledge Management System(KMS), there exists inefficiency in employee participation and system usage. In recent years, web itself is evolving into web 2.0. And It is crucial to utilize web 2.0 characteristics into KMS. The problems in the original version of KMS(KMS 1.0) is as follows. KMS is separated from Offline and electronic work processing systems. Even information in the electronic work processing system cannot be accessed by employees of other divisions in the same organization. Now web 2.0 environment provides more enhanced user participation and information sharing. It also reinforces KMS 1.0 into KMS 2.0. Small organizations should take advantage of web 2.0 environment and construct the better version KMS of its own with low-cost and high-efficiency.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.363-364
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• 2016

In this paper, a novel bridgeless interleaved power factor correction circuit with single current sensor is proposed. The proposed control strategy requires only one current sensor for the interleaved bridgeless PFC. By sampling the output current, all the boost indictor currents can be calculated and used to control the input current according to the input voltage. The reduced number of current sensors and associated feedback circuits helps reduce the cost of system. The problem caused by the unequal current gain between current sensors inherently does not exist in the proposed topology. Thus, current sharing between converters can be achieved more accurately and the high frequency distortion is decreased. In addition, the proposed technique can be applied to the other kinds of interleaved PFC topologies. Performance of the proposed control strategy is verified by the experimental results with 6.6kW bridgeless interleaved PFC circuit.

• 한국컴퓨터정보학회논문지
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• 제9권3호
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• pp.103-107
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• 2004

소프트웨어의 재사용은 생산성 향상, 소프트웨어의 신뢰성 향상, 소프트웨어 개발기간 단축, 개발비용 절감, 시스템 관련 정보 공유 등의 장점을 지닌다. 수직적 재사용은 하나의 영역 또는 응용 분야에서만 재사용함으로서, 높은 이해성으로 인해 재상용의 신뢰성을 높일 수 있는 방법이다. 소프트웨어 시스템을 개발할 때 사용되는 정보들을 재사용을 목적으로 분류하여, 결과물들을 추상화하는 상향식 방법을 이용하여 단순 코드의 재사용에서 벗어나 비형식적인 자료들을 포함해 모든 정보를 사용 가능하게 할 수 있다.

• 전력전자학회논문지
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• 제4권5호
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• pp.413-422
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• 1999

Auto-connected multipulse(12/24pulse) rectifier schemes are cost effective methods for reducing line current hamonics in PWM drive systems. Employing these schemes to enhance utility power quality requires careful attention to several design considerations In particular, excursion of dc-link voltage at no load, effect of pre-existing voltage distortion, impedance mismatches, unequal diode drops on rectifier current sharing and performance, are fully analyzed, Several corrective measures to improve the performance of 12/24­pulse rectifier systems are also discussed. Finally, experimental results on a 460V, 60Hz 400kVA commercial ASD, retrofitted with 12/24pulse rectifier systems are discussed in detail.