• Journal of Power System Engineering
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• v.15 no.1
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• pp.57-63
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• 2011

It is very important to determine link composition of a crane in the basic design of the crane. There are many parameters in the design for the link composition of a double link type level luffing jib crane. We analyze the variation of link composition according to the variation of these parameters which are the angle of fixed link, the angle between the fixed link and backstay when the position of the crane is the maximum working radius, the ratio of fly jib length between two moving hinges to the total length of fly jib, the length of backstay, and the slewing radius. In this paper, we describe the application of the previous analysis program of the link composition design for a double link type level luffing jib crane.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.531-536
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• 2007

기존의 웹 검색 시스템은 주어진 키워드들을 모두 포함한 웹 페이지의 도출을 목표로 하기 때문에, 검색어의 popularity가 떨어지는 경우나, 키워드의 한정 정도가 과도하거나 많아지는 경우, 또는 키워드가 길어지는 경우 등에는 검색결과가 크게 줄어드는 결과희소성 문제(scarcity problem)를 겪게 된다. 본 연구에서는 이를 해결하기 위해서 검색결과를 개별 웹페이지 집합이 아닌 관련 웹페이지들간의 링크 구조로 도출해주는 확장된 검색 방법을 제시한다. 확장된 웹 검색은 링크기반 분석을 활용하여 개별 질의들에 대한 검색 결과 페이지들간의 링크 관계를 탐색하고, 도출된 검색 결과의 순위 측정을 통해 이루어진다. 본 연구에서 제안하는 확장된 웹 검색 방법은 결과희소성 문제에 효과적임을 보였다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.397-398
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• 2010

본 논문에서는 고전력 밀도 및 저가형으로 구현 가능한 새로운 구조의 계통 연계형 태양광 인버터 시스템을 제안한다. 제안된 시스템은 링크 캐피시터와 배터리를 직렬 연결하여 링크 캐패시터의 전압 스트레스를 저감하였고, 이를 통하여 기존 대비 1/2의 캐패시터 사용이 가능하다. 제안 시스템의 우수성을 검증하기 위하여 1.5kW급 시작품을 제작하였고 이를 바탕으로 제안된 시스템의 타당성을 검증하였다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2001.05a
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• pp.55-63
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• 2001

IMT-2000 mobile system will serve many application services such as mobile internet, wireless electronics commerce applications using high data rate air interface. These applications require high data integrity, data confidentiality, user authentication, user identity confidentiality and non-repudiation. In this study, we analyze air interface performance fur network access security services in IMT-2000 mobile systems. Signal traffic for network access security services increase all link between IMT-2000 system elements. Our study focus on air interface, which is very sensitive signal traffic increase.

• Annual Conference of KIPS
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• 2000.10b
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• pp.1117-1120
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• 2000

인터넷 소프트웨어 개발자는 인터넷 보안 소프트웨어, 네트워크 실습 교육용 소프트웨어 등의 다양한 서비스 개발을 위해, 데이터 링크 계층의 프레임에 직접 접근하는 방법을 요구한다. 이러한 개발자를 위해, Windows 2000은 사용자 계층에서 인터넷 관련 네트워크 자원에 접근할 수 있는 Winsock, NPP, Internet Protocol Helper API를 지원한다. 하지만, 개발자가 이러한 API, 특히 Winsock API를 통해 직접 데이터 링크 계층의 프레임에 접근하는 데에는 한계가 있다. 따라서, 본 논문에서는 NDIS Library를 이용하여 일반 개발자가 손쉽게 데이터 링크 계층의 프레임에 접근할 수 있는 packet driver API를 설계하였다. API를 구성하는 각 클래스는 계층적 구조로 설계하였으며 Visual C++를 사용하여 구현하였다.

• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.34-38
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• 2009

This paper is related with optimum burst structure design for high efficient TDMA satellite return link transmission. In general, some typical burst structure for data transmission is composed of a pair of preamble and traffic data in the DVB-RCS (Digital Video Broadcasting. Return Channel via Satellite) and IPOS (IP over Satellite) standard. This structure has some difficulties to increase spectral efficiency that it requires a large of preamble length, high SNR environment, or receiver complexity. To cope with them, burst structure with distributed pilot symbol can be used to alleviate the residual frequency offset effect by calculating accurate frequency offset than conventional one. In particular, we investigate some relevant to proposed distributed pilot structure, previously and analyze their strong points/drawbacks in terms of synchronization to draw the most appropriate one.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3C
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• pp.302-313
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• 2010

In this paper, we propose an enhanced AGC (Automatic Gain Control) structure and P-SCH detection method for initial cell search in 3GPP (3rdGenerationPartnershipProject) LTE (Long Term Evolution) FDD(Frequency Division Duplex) / TDD (Time Division Duplex) dual mode system. Since TDD frame structure consists of uplink subframe and downlink subframe, conventional AGC structure causes P-SCH detection performance degradation by increase of AGC variation due to signal power difference between uplink and downlink subframe. Also, P-SCH detection performance is degraded by distortion of P-SCH correlation characteristic in frequency offset and multipath fading channel environments. Therefore, we propose an AGC structure which can minimize P-SCH detection performance degradation with stable operation in 3GPP LTE TDD mode as well as FDD mode. Also we propose a P-SCH detection method which can reduce distortion of correlation chareteristics in frequency offset and multipath fading environments and obtain good P-SCH detection performance. Simulation results show that the proposed AGC structure and P-SCH detection method have stable AGC operation and excellent P-SCH detection performance for 3GPP LTE TDD / FDD dual mode downlink receiver in various channel environments.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.749-756
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• 2015

In this paper, we propose a unique systolic structure and communication algorithm that maintains a solid link between nodes using synchronous digital communication and enables low power communication. This system was designed by using CC2500 RF transceiver, CC2590 RF front end and C8051F330 low power microcontroller. The measurement of power consumption in the network link shows below $400{\mu}W$ in data transfer rate 320bps. The system constitutes the base unit of low power wireless network that was composed of each seven link nodes having eight sensor nodes. Results of the experiments show that link nodes using a 4Ah battery could operate over 3 years without replacement.

• Journal of Advanced Navigation Technology
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• v.20 no.2
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• pp.161-166
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• 2016

In high capacity and long haul optical communication systems, signal distortion is induced by chromatic dispersion and nonlinear effects of optical fibers. Dispersion management (DM) combining with mid-spans spectral inversion (MSSI) is one of the various techniques for overcoming this drawback. The most simple configuration of DM link is obtained by uniformly distributing the lengths of single mode fiber (SMF) and residual dispersion per span (RDPS) over whole fiber spans consisted of optical link. In this paper, the system performances in the uniformly distributed DM link combined with MSSI are assessed as a function of the number of fiber spans, because the system performances in this configuration are used as the significant performance criterion in other link configurations, such as the artificial distribution or the random distribution of SMF lengths and RDPS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2293-2302
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• 2012

New optical transmission links technique for compensating of the distorted wavelength division multiplexed (WDM) signals due to group velocity dispersion (GVD) and self phase modulation (SPM) in single mode fiber (SMF) are proposed. The proposed optical links have optical phase conjugator (OPC) placed at nearby WDM transmitter or receiver and repeater spans with artificial distribution of SMF length and residual dispersion per span (RDPS). It is confirmed that optimal link configuration expanding effective launching power range and effective net residual dispersion (NRD) by improving system performance is that having OPC closely placed at WDM receiver and the gradually descended distribution of SMF length and RDPS of each repeater spans, related with the gradually increased optical link length. And, it is also confirmed that NRD is controlled by postcompensation in optimal optical link with OPC closely placed at WDM receiver.