• ETRI Journal
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• 제30권4호
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• pp.535-545
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• 2008

This paper introduces a systematic top-down and bottom-up design methodology to assist the designer in the implementation of continuous-time (CT) cascade sigma-delta (${\Sigma}{\Delta}$) modulators. The salient features of this methodology are (a) flexible behavioral modeling for optimum accuracy-efficiency trade-offs at different stages of the top-down synthesis process, (b) direct synthesis in the continuous-time domain for minimum circuit complexity and sensitivity, (c) mixed knowledge-based and optimization-based architectural exploration and specification transmission for enhanced circuit performance, and (d) use of Pareto-optimal fronts of building blocks to reduce re-design iterations. The applicability of this methodology will be illustrated via the design of a 12-bit 20 MHz CT ${\Sigma}{\Delta}$ modulator in a 1.2 V 130 nm CMOS technology.

• 대한안전경영과학회지
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• 제12권3호
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• pp.295-302
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• 2010

Nowadays, due to the development of computers and the information and communication technology, data processing and transmission is made very vastly and fast. The development of the technologies bring many changes and revolutions to the life of ordinary people. Although, e-Business grows continuously, it is in experimental stage in domestic area because of limits of infrastructure. Also, in spite of explosive growth of internet, the research on the internet has not been fully studied yet. The objectives of this study are that how service consumers perceive the flow of e-Business, and that what effect the makes on their satisfaction and re-purchase intention. This means that the research enables a marketing manager to take the meaning of comparative weight among the components of e-Business flow, and to provide very useful information to establish marketing strategies which are close to the consumers.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.1001-1004
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• 2000

RFID system is applied to identify, locate and track people, cars, animals. In RFID system, the passive transponder without battery has some benefits than active transponder, such as no restriction in battery exchange and in battery’s life. But it needs auxiliary RF-DC conversion circuit. RF-DC conversion circuit originated from Wireless Power Transmission (WPT). In this paper, RF-DC conversion circuit consists of a microstrip patch antenna and impedance matching circuit, Cock-croft Walton circuit. And RF-DC conversion circuits have two kinds of T-type and Cross-type impedance matching circuits.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1188-1195
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• 2014

This paper presents an analytical technique for reliability evaluation of electrical distribution network (EDN) containing distributed generation (DG). Based on hierarchical levels of circuit breaker controlling zones and feeder sections, a directed-relation-graph (DRG) for an END is formed to describe the hierarchical structure of the EDN. The reliability indices of EDN and load points can be evaluated directly using the formed DRG, and the reliability evaluation of an EDN containing DGs can also be done without re-forming the DRG. The proposed technique incorporates multi-state models of photovoltaic and diesel generations, as well as weather factors. The IEEE-RBTS Bus 6 EDN is used to validate the proposed technique; and a practical campus EDN containing DG was also analyzed using the proposed technique.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.405-410
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• 2011

In this paper, a conflict-avoided resource reservation scheme for UWB (Ultra Wide Band) WPAN (Wireless Personal Area Network) with D-MAC (Distributed Medium Access Control) is proposed. Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WiMedia D-MAC can be deteriorated. In addition, once a DRP conflict occurs, only one of the DRP reservations involved in that DRP conflict maintains the reserved MASs, while the other DRP reservation must be terminated and DRP negotiations for them have to be re-started. Such DRP termination and renegotiation time delays due to the DRP conflicts can be a critical problem to the mobile devices transceiving real-time QoS traffic streams. Therefore, we propose a mechanism to avoid DRP conflicts by providing a kind of path diversity using relay transmission scheme and demonstrate its performance improvements via simulation results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.286.1-286.1
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• 2013

Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.

• 한국멀티미디어학회논문지
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• 제7권6호
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• pp.814-823
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• 2004

Current video games and game room games are played as a single player mode on the basis of various emulators. With the evolution of data communications and game technology, a new trend in the game industry has made the primary interests of game developers and companies in the game industry be moved toward a multiplayer mode from the traditional single player mode. In this paper, we represent how to implement a network game platform by allowing network modules to be run in conjunction with the current video emulator games. It also suggests a synchronization scheme for real-time game playout and practical mechanism that can support network games to be played with the Peer-to-Peer process using a lobby system.

• 한국항행학회논문지
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• 제17권3호
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• pp.285-291
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• 2013

본 논문에서는 무선 애드 혹 링크 품질을 보장하기 위하여 새로운 STM기반의 미디어 스트리밍 기법을 제안 하였다. 제안된 기법은 스트리밍 모니터링, 스트리밍 보장, 그리고 스트리밍 갱신과정을 거쳐 링크 품질이 보장되도록 하였으며, 스트리밍 $t_{new}$에 의해 미디어 프레임들이 모니터링되도록 하였다. 그리고 프레임의 크기에 따른 미디어 스트리밍 갱신 알고리즘을 이용하여 링크 오류율과 재전송률을 최소화하도록 하였다. 시뮬레이션 결과 제안된 기법이 STCP기법, 그리고 RMST기법에 비해서 성능이 우수함을 보인다.

• Journal of the Optical Society of Korea
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• 제7권1호
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• pp.28-33
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• 2003

We describe the optimal design and the fabrication of a 2$\times$2 port optical device based on the thin film filter (TFF), and also propose a 4-channel OADM module using these devices. The optical performance of the proposed OADM module is evaluated theoretically and experimentally, and is compared to that of typical OADM modules using 1$\times$2 port optical devices for 4, 8, 16 and 32 drop channels in optical transmission systems. Since the 2$\times$2 port optical device accomplishes the function of wavelength multiplexing and demultiplexing simultaneously in the proposed OADM module, the insertion loss of through channels can be improved by 1.2 dB compare to that of typical OADM modules using 1$\times$2 port optical devices. In addition, both the size and the price of the module can be reduced to 40~50%.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2004년도 춘계학술발표대회
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• pp.1493-1496
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• 2004

디지털 방송을 수신하는 셋탑박스가 IEEE1394 시리얼 버스를 사용하여 홈네트워크 상의 다른 위치에 존재하는 디스플레이 장치로 수신된 방송 컨텐츠를 재전송 하고 방송중인 채널의 변경이 가능하게 한다. 방송 스트림의 재전송은 IEEE1394 의 등시성 전송 방식을 이용하여 질적 열화가 없고 QoS가 보장되는 형태로 전송이 가능하도록 하며, 채널의 변경은 채널 변경 프로토콜을 이용하여 비동기 전송 방식을 통해 전달하여 데이터 전송의 명확성을 부여할 수 있다. 본 논문은 셋탑박스를 통해시청중인 방송의 채널 변경과 확인 등의 작업을 위한 프로토콜을 제공하여, 댁내에서 방송 및 MPEG2 TS 스트림의 재전송을 가능하게 하는 기법을 제안한다.