• 대한전자공학회논문지TC
• /
• 제44권4호
• /
• pp.59-64
• /
• 2007

본 논문에서는 DBO-CSS를 위한 새로운 수신기 구조를 제안한다. DBO-CSS에서는 정보가 인접한 서브첩(sub-chirp)간의 차분 위상이 아니라 인접한 풀첩(full-chirp) 내의동일 위치에 있는 서브첩간의 차분위상에 실리게 된다. 따라서, DBO-CSS의 BER 성능 향상을 위해 일반적인 MSDD(multiple symbol differential detection) 알고리듬 등은 바로 적용할 수 없다. 본 논문에서는 부분적 MSD(multiple symbol detection)와 viterbi 알고리듬에 기반한 새로운 차분 검출 알고리듬을 제안한다. 실험결과, 제안하는 구조는 기존의 차분 검출 방식과 biorthogonal 복호기로 구성된 수신기에 비해 BER=10-5일 때 약 2.5dB의 SNR이 향상됨을 확인하였다.

• ETRI Journal
• /
• 제42권3호
• /
• pp.324-332
• /
• 2020

In this paper, a blind symbol timing offset (STO) estimation method is proposed for offset quadrature phase-shift keying (OQPSK) modulated signals, which also works for other linearly modulated signals (LMS) such as binary-PSK, QPSK, 𝜋/4-QPSK, and minimum-shift keying. There are various methods available for blind STO estimation of LMS; however, none work in the case of OQPSK modulated signals. The popular cyclic correlation method fails to estimate STO for OQPSK signals, as the offset present between the in-phase (I) and quadrature (Q) components causes the cyclic peak to disappear at the symbol rate frequency. In the proposed method, a set of close and approximate offsets is used to compensate the offset between the I and Q components of the received OQPSK signal. The STO in the time domain is represented as a phase in the cyclic frequency domain. The STO is therefore calculated by obtaining the phase of the cyclic peak at the symbol rate frequency. The method is validated through extensive theoretical study, simulation, and testbed implementation. The proposed estimation method exhibits robust performance in the presence of unknown carrier phase offset and frequency offset.

• 복식
• /
• 제59권2호
• /
• pp.143-153
• /
• 2009

The purpose of this study is to provide color information in order to planning and merchandising in china fashion through the color of Beijing opera. In objective study, we collect total 302 Beijing opera images. The collecting method of source data is to extract digital color data by color picker. We transform RGB color data to H V/C, CIE L*a*b and analyze the attributes of color and tone, three-dimensional analysis. The results of this study are as follows : 1. The color distrbution of Beijing opera is R(26.9%)>YR(18.2%)>PB(11.6%)>Y(9.6%). Traditional preference color, red is most popular color as 26.7%:, the practice of vivid tone red is numerous. 2. The tone distribution of Beijing opera costume is P(16%)>It(13.9%)>d(11%)>5(9.6%)>4kg (8.2%)>b(7.1%:). The value o# Beijing opera costume distribute medium and medium-high and the chroma of those distributes low. 3. High chroma yellow is restrictive color as the symbol of emperor in china but medium-low chroma yellow is very frequently used. 4. Blue is often used in china costume. Especially in Beijing opera costume blue is symbol of bravery, dignity, cruel character 5. White in Beijing opera costume is much used for symbol of righteous loyalist. Black is less used than white in Beijing opera costume and black is authority color for symbol of the prime minister.

• 한국의류학회지
• /
• 제2권2호
• /
• pp.261-267
• /
• 1978

The purpose of this study was to investigate the relationship between clothing behaviors and general values of Che-ju college women. General values were measured by The Allport-Vernon-Lindzey Study of Value, which determines the relative prominence of six basic values. General clothing behaviors were assessed by statements dealing with interests in status symbol, fashion and practicality of clothing. Measures of attitudes toward blue jeans consists of: attitudes regarding practicality and youth symbol. In addition the possession, and frequency of wearing blue jeans were assessed. The sample consisted of 284 students in Che-ju college women, Korea. The data, collected by means of a self-administered questionnaire, were analyzed by correlations and t-tests. The results indicate that: 1) Economic value was positively related to the status symbol of clothing. 2) No correlation was found between political value and the fashion of clothing. 3) Social value was positively related to the practicality of clothing, however, no correlation was found between social value and attitudes regarding practicality of blue jeans. 4) Practicality attitudes toward blue jeans was positively related to the practicality of clothing, whereas youth symbol attitudes toward blue jeans was positively related to the fashion and the status symbol of clothing. 5) The groupth which had blue jeans had higher interest of fashion in clothing than the groupth which had no blue jeans.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권2호
• /
• pp.255-266
• /
• 2015

In this paper, a low-complexity and low-power soft output multiple input multiple output (MIMO) symbol detector is proposed for mobile devices with two transmit and two receive antennas. The proposed symbol detector can support both the spatial multiplexing mode and spatial diversity mode in single hardware and shows the optimal maximum likelihood (ML) performance. By applying a multi-stage pipeline structure and using a complex multiplier based on the polar-coordinate, the complexity of the proposed architecture is dramatically decreased. Also, by applying a clock-gating scheme to the internal modules for MIMO modes, the power consumption is also reduced. The proposed symbol detector was designed using a hardware description language (HDL) and implemented using a 65nm CMOS standard cell library. With the proposed architecture, the proposed MIMO detector takes up an area of approximately $0.31mm^2$ with 183K equivalent gates and achieves a 150Mbps throughput. Also, the power estimation results show that the proposed MIMO detector can reduce the power consumption by a maximum of 85% for the various test cases.

• 대한지리학회지
• /
• 제43권4호
• /
• pp.638-654
• /
• 2008

본 연구에서는 설문조사를 통해 중학생들의 도형표현도 인지 능력을 알아보려 했다. 분석 결과 3가지 사실을 확인할 수 있었는데, 우선 과소추정 경향은 지수함수로 나타나며, 선기호, 사각기호, 원기호, 입체기호 순으로 과소추정 정도가 증가하였다. 둘째, 범례의 수(3, 5, 7개), 범례 표현방법(나열, 포섭), 기호 크기 척도 체계(비례적, 심리적)에 따라 기호의 크기가 상이하게 인지되고 있음을 확인하였다. 마지막으로 범례에 비해 기호의 크기를 과대추정 하는 경향이 있었고, 1학년과 3학년의 기호 인지 능력에서는 차이를 보이지 않았다.

• 대한수학교육학회지:수학교육학연구
• /
• 제20권4호
• /
• pp.511-528
• /
• 2010

기하적 성질을 이해하고 받아들이는 데 있어서 중요한 직관은 학습을 통해서도 형성될 수 있다. 본 연구는 2명의 학생을 대상으로 기호화, 문장화, 증명 과제를 수행하게 하여 기하 증명에서 기호의 중재에 의한 직관의 형성 과정을 살펴본다. 학생들에게 자명하고 당연하게 여겨지는 단정적 직관의 유무에 따라 기호가 어떤 역할을 하는지 살펴보고, 예상적 직관이 형성되지 않은 증명 문제에서 학생들이 기존 지식을 활용하여 증명을 완성하는 과정을 기호의 의미작용에 의해 설명한다. 마지막으로 피타고라스의 정리에 대해 기호의 중재에 의해서 결론적 직관이 형성되는 과정을 살펴본다.

• 한국의류학회지
• /
• 제9권3호
• /
• pp.27-34
• /
• 1985

The purpose of this study was to investigate the relationship between four aspects of clothing behavior and perceptual orientation, and between those and job satisfaction of white-collar men. Those aspects of clothing behavior included: clothing conformity, clothing satisfaction, status symbol and occupation symbol. Perceptual orientation was measured with Choi's Perceptual Orientation Scale and job satisfaction, with some items of Miller's The Attitude Toward Any Occupation Scale. Clothing comformity and clothing satisfaction were measured with Kahng's, lung's, Koh's and Lee's questionaire. Status symbol was measured with Koh's and Lee's questionaire, and occupation symbol items were prepared for this study. The questionaire in this study were administered to 323 white-collar workers in Seoul. The statistical methods utilized Pearson'a product moment correlation, one-way ANOVA test, Duncan's multiple range test and multiple regression analysis. The results obtained from this study were : 1. Perceptual orientation was positively correlated to clothing satisfaction, and negatively correlated to status symbol. 2. Job satisfaction was positively correlated to clothing satisfaction and clothing comformity. 3. Clothing conformity, clothing satisfaction and job satisfaction showed significant differences according to occupation.

• 한국통신학회논문지
• /
• 제33권11C호
• /
• pp.932-939
• /
• 2008

공간 다중화 방식의 MIMO(Multiple-Input Multiple-Output) 시스템에서 MLD(Maximum-Likelihood Detector)는 최적의 성능을 보이지만, 그 복잡성이 상당히 큰 단점이 있다. 이를 보완하기 위해 여러 가지 기법들이 제안되었으며, Lattice-reduction(LR) 검출기 또한 MIMO 시스템의 성능을 개선하기 위해 제안되었다. 본 논문에서는 확장된 잡음분산 행렬을 이용해 rounding operation 과정에서 발생하는 양자화 오류를 이용해 송신 신호 벡터에 근접한 candidate symbol set을 찾고, 여기서 Semidefinite Relaxation을 이용해 최대 우도 symbol을 검출한다. 그러나 그 복잡도는 MLD의 복잡도 보다 현저히 작고, LR 검출기의 복잡도에 근접한다.

• 한국통신학회논문지
• /
• 제31권3A호
• /
• pp.214-220
• /
• 2006

본 논문에서는 TPC-AMS/FSS-OFDM(transmit power controlled adaptive modulated OFDM with frequency symbol spreading and equalization)시스템을 제안한다. TPC-AMS/FSS-OFDM의 송신기에서 각 S/P(serial-to-parallel)변환된 신호는 직교 확산 코드에 의해 확산 결합되어 송신하고, 수신된 신호는 수신기의 각 주파수 심볼 확산 블록에 의하여 검출되며, 같은 SINR(signal interference to noise ratio)을 얻는다. 이 때 각 주파수 심볼 확산블록에 대해서는 같은 변조 레벨과 송신 전력을 할당할 수 있다. 본 논문에서 제안한 시스템은 전체 송신 전력과 데이터 정보로 전송되는 FBI(feedback information), MLI(modulation level information)를 감소시킴으로서 전체적인 전송속도(throughput)의 성능을 개선할 수 있다.