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Channel Estimation and Detection Techniques for OFDM Systems in Time Varying Channels (OFDM 시스템에서의 시변 채널 추정 및 신호 검출)

  • 김형중;박정호;박병준;김지형;강창언;홍대식
    • Proceedings of the IEEK Conference
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    • 2003.07a
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    • pp.418-421
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    • 2003
  • In this thesis, a new channel estimation technique is proposed for orthogonal frequency division multiplexing (OFDM) over time varying channels. The channel estimation algorithm exploits the fact that the estimated channel impulse response (CIR) by using pilot signal is the average value of the CIR variation within an OFDM symbol period. With this fact, the CIR variation is simply estimated through lowpass interpolation of the CIRs of the adjacent OFDM symbols. For signal detection, a time domain equalizer is used in this thesis. Simulation results show that the proposed system improves the bit error rate (BER) over time varying channels.

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Development of Integrated Water Operation System through Engineering Standardization (표준화를 통한 통합형 수(水)운영시스템의 개발)

  • Han, Geung-Jeon;Kim, Jin-Mun;Jeon, Hwa-Sung;Lee, Kyung-Woo
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.6
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    • pp.602-609
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    • 2011
  • In this paper, we standardized the water operation system picture, process control logic, realtime database and system configuration. All aspects, including monitoring & controlling processes, symbols such as pumps, valves and pipes were standardized. As a result we have developed a specialized Integrated water operation system, iWater. We have developed a variety of advanced application programs that are essential for water treatment systems, such as IWS (Integrated Warning system), MBO(modbus opc)/LSE(LS ethernet) driver, video monitoring, self diagnosis system, network monitoring, etc. IWS prevents water supply accidents by using a variety of alarms and warning messages. Drivers have the flexibility to communicate with other 3rd party systems. We expect that iWater will eliminate any concerns regarding water-related issues while also promoting the production and fair distribution of clean water.

A Study on an Embedded DPCM with Convolutional Coding (길쌈부호를 사용한 Embedded DPCM 방식에 관한 연구)

  • 임종수;이상곤;문상재
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.28A no.1
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    • pp.1-7
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    • 1991
  • Degradation of communication quality is due to transmission error rather than quantization noise when DPCM signal is transmitted over a heavily noise channel. The communication quality can be improved by employing an error correcting code to the DPCM signal transmission over such a channel. We considered both quantization noise and transmission error simultaneously in evaluating the signal to noise ratio. To efficiently improve the signal to noise ratio, we analyze the unequal symbol error probability of convolutional code, and encoded to more protect significant symbols from channel errors than least ones, so that the signal to noise ratio is improved. We derived related formulas and also made computer simulations.

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Alternate Time-Switched Space Frequency Block Coding Technique for Single-Carrier System (단일 반송파 시스템을 위한 교번 스위칭 공간 주파수 블록 코딩 기법)

  • Jung, Hyeok-Koo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.1
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    • pp.29-33
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    • 2014
  • This paper proposes an alternate time-switched space-frequency block coding transmission technique for single-carrier modulation with frequency domain equalization. There are two antennas in the transmitter but it still has only a baseband and RF and a switch that alternates between the antennas at every symbol timing. Alternating transmit symbols result in zeros which make maximal ratio receive combining possible in the receiver. Simulation results show that it has better performance than the traditional algorithm at the expense of one additional antenna.

Application of Reliability Centered Maintenance for Waterworks after Constructing CMMS (Computerized Maintenance Management System) (유지관리업무 시스템(CMMS) 구축에 따른 수력발전 및 수도설비를 위한 신뢰도 기반 유지보수(RCM) 적용)

  • Lee, Sung-Hoon;Lee, Jong-Bum;Kim, Jeong-Rak
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.424-425
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    • 2008
  • This paper presents application of RCM(Reliability Centered Maintenance) in waterworks system. The reliability-based probability model for predicting the failure probability is established and FTA(Fault Tree Analysis) is proposed to considering RCM. To calculate failure probability, Weibull distribution is usually used due to age related reliability. FTA is an engineering analysis which is using logic symbols. The real historical data of CMMS(Computerized Maintenance Management System) make full use of case study for waterworks system. Consequently, the RCM would be likely to permit utilities to reduce overall costs in maintenance and improve the total benefit.

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Full-Diversity High-Rate STBC for 2 and 4 Transmitted Antennas (2,4개 전송 안테나를 위한 완전 다이버시티 고 부호율 STBC)

  • Yan, Yier;Lee, Moon-Ho;Ma, Yizhou
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.295-297
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    • 2007
  • We design a new rate-3/2 full-diversity orthogonal space-time block code (STBC) for QPSK and 2 transmit antennas (TX) and 4 transmit antennas (TX) by enlarging the signalling set from the set of quaternions used in the Alamouti[I] and extendedcode and using additional members of the set of orthogonal matrices or Quasi-orthogonal matrices and higher than rate-5/4. Selective power scaling of information symbols is used to guarantee full-diversity while maximizing the coding gain (CG) and minimizing the transmitted signal peak-to-minimum power ratio (PMPR). The optimum power scaling factor is derived analytically and shown to outpetform schemes based only on constellation rotation while still enjoying a low-complexity maximum likelihood (ML) decoding algorithm.

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Characteristics of Blue Costumes in Contemporary Fashion (현대패션에 나타난 블루의상의 특성)

  • Kim, Sun-Young
    • Journal of the Korean Home Economics Association
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    • v.49 no.8
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    • pp.13-24
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    • 2011
  • This paper purports to find the characteristics of blue costumes as expressed in modern fashion. As such, we made an empirical analysis, using 436 works from 2006 S/S through 2010 F/W collections. Result indicated that modernness was emphasized by applying a minimum expressive technique to items of a simple form, and an image of simplicity was emphasized by placing focus on the rational color image of blue. Second, images of blue, such as trust, stability, and success were expressed as refined elegance through the combination of tight silhouettes, glossy and translucent materials, and indirect exposure. Third, natural image was expressed through natural silhouettes, soft or natural materials, gradation of various tones, and natural motif decorations as well as the color itself. Fourth, dynamic image was expressed by introducing fashion items, mostly worn by men only, to simple and tight forms or through the inspiration of a masculine fashion image. Fifth, abstinent image was expressed by using an image of religious apparel or symbols, covering up the body, minimizing details, and using a dark blue tone.

The Study of Religious Motifs in Contemporary Fashion (현대패션에 나타난 종교적 모티브에 관한 연구)

  • Kim, Sun-Young
    • Journal of the Korean Home Economics Association
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    • v.48 no.8
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    • pp.39-50
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    • 2010
  • This study aimed to identify today's religious fashion motifs as elements for design development by examining the expression modes such as religious motifs in contemporary fashion. Methodologically, the study conducted literature review and empirical analysis of pictures and articles in domestic and foreign fashion collection magazines and other related data available on the internet and analyzed the collections of 1990 through 2009 with a focus on Christianity, Buddhism and Islam. As a result, this study identified two expression modes of religious motifs in the contemporary fashion. The first expression mode was to employ the forms of religious costumes and their associated images. The second one was to take on religious symbols and their associated images.

A Study on the Sexuality Expressed in Modern Fashion - Focusing on the Feminism (현대 패션에 나타난 섹슈얼리티에 관한 연구 -페미니즘 이론을 중심으로-)

  • Lee, Ji-Hyoun;Yang, Sook-Hi
    • Journal of the Korean Society of Costume
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    • v.57 no.10
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    • pp.11-23
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    • 2007
  • The purpose of this study is to express the sexuality of feminism in the modern fashion. As for the methods of research, literary research was carried out using reference based on feminism history and sexuality concept and demonstrative analysis was undertaken using 2000's collections photographs. In the results of that, the sexuality of gender resistance feminism is featured by three key words: sado-masochism sexuality, bi sexuality and hetero sexuality. First, sado-masochism sexuality shows fetish look and dominatrix look shown in the strong attitudes. Sado-masochism sexuality is setting fetishes such as mask, whip, chain, metallic materials and tight leather boots. Second, bi sexuality presents mannish look of soft and feminie style's slim pants suit with ruffle, flounce and decorated detail blouse. and fetish look wearing of sexual symbol clothes such as corset and bustier. Third, hetero sexuality represent glamour look which exposure and emphasis of breasts, hips and other sexual symbols.

A study on the problems of transport document as a proof of delivery on INCOTERMS 2000 (매도인(賣渡人)이 제공하는 인도증빙서류(引渡證憑書類)의 문제점(問題點)에 관한 연구(硏究) (INCOTERMS 2000을 중심(中心)으로))

  • Oh, Won-Suk
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.14
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    • pp.7-35
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    • 2000
  • The purpose of this paper is to examine the meanings of delivery of each trade term in INCOTERMS 2000, to investigate various kinds of transport document as a proof of delivery, and finally to find their problems. As a result of examination, following problems are considered to happen practically. First, a multimodal transport document referred in FOB term seems to be unappropriate because FOB term can be used in sea or inland waterway transport. Second, Assuming resale in transit in CFR or CIF term, non-negotiable Sea Waybill seems to be inappropriate. Third, As Sea Waybill is not a document of title, it can not be a security when the bank negotiate seller's draft. Fourth, INCOTERMS 2000 deleted the reference to charter party in CFR or CIF term. This deletion may raise any legal problems for the liabilities of carrier when the contradictions happen between the charter party B/L and charter party. Finally, if CFR or CIF means symbolic delivery, other documents besides B/L can not be a symbols of goods.

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