• 대한전자공학회논문지TC
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• 제49권8호
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• pp.70-76
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• 2012

본 논문에서는 TV 화이트 스페이스(TV white space, TVWS)에서 OFDM(orthogonal frequency division multiplexing) 기반 비인가 사용자의 파워 할당 기법을 제안한다. 비인가 사용자는 TVWS를 사용할 때, 시간 도메인에서 TVWS의 파워 제약조건을 충족시키기 위해 전송 파워를 조절해야 한다. TDM(time division multiplexing) 혹은 FDM (frequency division multiplexing)과 달리 OFDM은 시간 도메인에서 높은 PAPR(peak-to-average power ratio)을 가지기 때문에, 기존의 비인가 사용자의 파워 할당 기법이 TVWS에 적용될 경우 TVWS의 파워 제약 조건을 충족시킬 수 없게 된다. 그러므로 본 논문에서는 OFDM의 높은 PAPR값을 제어하여 순시적으로 TVWS의 파워 제약 조건을 만족시킬 수 있는 새로운 파워 할당 기법을 제안한다. 또한, 이를 기반으로 OFDM 기반 비인가 사용자의 용량을 닫힌 형태(closed form)로 분석한다. 이에 따르면, 부반송파의 개수를 줄일수록 용량을 향상시킬 수 있다. 모의실험을 통해서, 비인가 사용자의 용량은 부반송파 개수가 작아질수록, 비인가 사용자의 송신단-수신단 간 채널 평균값이 커질수록 증가하는 것을 보여준다.

• 방송공학회논문지
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• 제9권4호
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• pp.371-383
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• 2004

본 논문에서는 단일 주파수 망(Single Frequency Network: SFN)을 통해 ATSC(Advanced Television Systems Committee) 지상과 디지털 TV 방송을 서비스하기 위해 필요한 기술적인 요구 사항에 대하여 고찰하고, 기존 디지털 동일 채널 중계기(Digital On-Channel Repeater: DOCK)가 가지는 단점을 극복한 등화형 동일 채널 중계기(Equalization Digital On-Channel Repeater: EDOCR)를 제안한다. EDOCR은 오류정정(Forward Error Correction: FEC) 복호 및 부호화부를 사용하지 않기 때문에 모호성(ambiguity) 문제가 발생하지 않아서 EDOCR의 입력 신호와 출력 신호가 동일하며, 고성능 등화기를 사용하여 주송신기와 EDOCR 사이의 전송로에 의해 야기된 잡음 및 다중경로 신호를 제거하므로 EDOCR 출력 신호의 품질이 입력 신호 보다 우수하다. 또한 낮은 안테나 격리도(isolation)로 인해 야기된 궤환(feedback) 신호를 EDOCR 등화기에서 제거할 수 있기 때문에 송신 출력을 높일 수 있다.

• 대한전기학회논문지:전력기술부문A
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• 제49권8호
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• pp.412-417
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• 2000

TV ghost interference can be described as passive interference by the conducting part of transmission lines. In order to survey this interference from large-sized overhead EHV (extra high voltage) transmission line, TV reception quality was measured in the vicinity of that before and after construction. Instrumentation system was composed of ghost analyzer, TV received field intensity meter, VHF/UHF antennas, TV monitor and so on. The system is installed inside the vehicle. TV field intensity and PDUR (Perceived Desired wave to Undersired wave Ratio) are measured to evaluate TV ghost by using the system and vehicle. As the results, the useful data, which can be used to evaluate the effect of TV ghost interference from transmission lines could be obtained. In this paper, it is shown that the range of TV ghost interference from transmission lines can vary according to the frequency of TV electromagnetic wave, an incidence angle to the line and the other conditiions. At present, we are making efforts to establish a PDUR guideline for transmission lines.

• 한국통신학회논문지
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• 제41권11호
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• pp.1364-1373
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• 2016

HDTV(High definition TV)보다 크게 개선된 UHDTV(Ultra High Definition TV) 방송이 차세대 방송 서비스로 주목받고 있다. UHD의 상용화를 위해 DVB(Digital Vedio Broadcasting)와 ATSC(Advanced Television Systems Committee)등의 표준화 기구들이 대부분 OFDM(Orthogonal Frequency Division Multiplexing)을 차세대 방송시스템의 전송 표준으로 채택하고 있다. OFDM은 송신단과 수신단의 반송파 주파수가 일치하지 않으면 직교성이 파괴되므로, 주파수 오프셋 추정을 통해 OFDM의 직교성을 유지한다. 그러나, 차세대 지상파 방송시스템에 서는 이와 같은 주파수 오프셋 추정 방법과 관련해서 구체적인 방법들이 제시된 경우가 많지 않다. 이에 따라서, 본 논문은 차세대 방송시스템 표준의 하나인 ATSC 3.0 시스템의 부트스트랩을 이용한 소수배 주파수 오프셋 추정 방법을 제안한다. 제안하는 방법에서는 소수배 주파수 오프셋 추정이 불가능한 기존 ATSC 3.0 검출기에 복소 켤레의 곱을 추가하여 소수배 주파수 오프셋 추정이 가능하도록 하였다.

• 한국의류학회지
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• 제21권5호
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• pp.880-888
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• 1997

This study was intended to analyze the perception of consumers towards TV commercials of women's clothes and variables influencing the effectiveness of the commercials. The sample consisted of 408 female students attending Ehwa Woman's university and the survey was conducted after the TV commercials were shown to the sample. Frequency, percentage, F-test, logistic regression were used for analysis. Conclusions of the study are as follows, 1. TV commercials were grouped into three image categories, Individuality, Nobility, and Activity. The commercials of the formal clothes were perceived based on nobility factor while the commercials of the casual clothes were perceived based on individuality factor by subjects. 2. Commercial image and the brand image appeared similar in three image factors. And TV commercials were more effective when two images were perceived similar. 3. The expenditures on TV commercial influenced the awareness of commercials, therefore frequent commercial drew more awareness. 4. The models on the commercials were more effective when the image of the commercials and the image of the models were perceived similar by subjects.

• 한국의류산업학회지
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• 제13권1호
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• pp.107-115
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• 2011

This study analyzes how the person-environment fit on organization attractiveness, commitment, and job satisfaction in TV home shopping companies. The survey was conducted from May 3 to 31 in 2010, and 350 responses were used in the data analysis. The statistical analysis methods were frequency analysis, factor analysis, reliability analysis, and multiple regression analysis. The results show that person-environment fit of TV home shopping companies is composed of person-job fit, person-supervisor fit, and person-organization fit. The person-job fit, person-supervisor fit, and person-organization fit of TV home shopping companies influence the organization attractiveness and commitment. The organization attractiveness and commitment affect the job satisfaction in TV home shopping companies.

• ETRI Journal
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• 제40권2호
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• pp.167-179
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• 2018

This paper proposes an IEEE 802.15.4m compliant TV white-space orthogonal frequency-division multiplexing (TVWS)-(OFDM) radio frequency (RF) transceiver that can be adopted in advanced metering infrastructures, universal remote controllers, smart factories, consumer electronics, and other areas. The proposed TVWS-OFDM RF transceiver consists of a receiver, a transmitter, a 25% duty-cycle local oscillator generator, and a delta-sigma fractional-N phase-locked loop. In the TV band from 470 MHz to 698 MHz, the highly linear RF transmitter protects the occupied TV signals, and the high-Q filtering RF receiver is tolerable to in-band interferers as strong as -20 dBm at a 3-MHz offset. The proposed TVWS-OFDM RF transceiver is fabricated using a $0.13-{\mu}m$ CMOS process, and consumes 47 mA in the Tx mode and 35 mA in the Rx mode. The fabricated chip shows a Tx average power of 0 dBm with an error-vector-magnitude of < 3%, and a sensitivity level of -103 dBm with a packet-error-rate of < 3%. Using the implemented TVWS-OFDM modules, a public demonstration of electricity metering was successfully carried out.

• 한국인터넷방송통신학회논문지
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• 제13권2호
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• pp.269-273
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• 2013

본 논문은 대표적인 전파응용기기로 알려진 PDP(Plasma Display Panel) TV와 RF(Radio Frequency) 전구가 30MHz 이하 무선 서비스에 대한 전자기기의 잠재적 간섭 영향을 분석한 것이다. PDP TV와 RF 전구의 방사 크기를 전자파무반사실에서 측정하였고 이를 바탕으로 다수의 간섭 신호가 존재하는 경우에 결합된 간섭신호의 크기를 계산하였다. 분석 결과, 간섭원의 수에 따라 결합된 간섭 신호의 크기가 증가되는 경향을 확인하였다. 실험을 통해 얻어진 전자기기의 방사 측정값과 CISPR(International Special Committee on Radio Interference) 11의 제한치를 비교함으로 30MHz 이하의 무선 서비스에 대한 전자기기 간섭 잠재성을 확인하였다.

• 한국의류산업학회지
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• 제1권3호
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• pp.231-238
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• 1999

The purpose of this study was to identify characteristics and consumer attitude on purchasing apparel of Cable TV home-shopping viewer: A questionnaire was developed to measure watching attributes, consumers' attitude and actual purchasing condition of Cable TV home shopping, and demographic variables. The questionnaire was administered to 277 adult, and the data were analyzed by using frequency; crosstab, t-test, ANOVA. The results of this study were as follows: 1. main view time were 3~5 p.m. 11 p.m, 10~12 a.m. home shopping through Cable Tv. Women's main terms were afternoon, whereas men's main terms were night. Chiefly view program was about apparel and fashion items. The reason why they watched the home-shopping channel was to purchase more cheaper items. 2. Favor about Cable TV home-shopping was relatively affirmative, but purchasing intention through home-shopping was still negative. But affirmative response was gradually increasing a few years ago. 3. Purchasing experience through Cable TV home shopping was 61.0% and clothing purchaser within recently 6 months was 28.5% of total sample. Withspreading Cable TV widely; Cable TV home shopper was gradually increasing. Heavy purchasing items through Cable TV home-shopping were under-wear; muffler, shawl, because those items are standardized in size and style. When home shopping user made purchasing decision, the most significant factors were color; and size (fit), price in order of importance.

• 한국의류학회지
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• 제27권5호
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• pp.588-599
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• 2003

The convenience of TV home shopping is known to provoke compulsive buying, which is chronic and repetitive purchasing behavior that comes about as a response to negative events or feelings. The purpose of this study was to identify whether there is a difference in the degree of compulsive buying between the purchasers of fashion goods and the purchasers of non-fashion goods on TV home shopping shows and the determinants of compulsive buying and their relative importance. Utilizing the convenient sampling method, the sample of the study was composed of women aged over 20 living in the Seoul metropolitan area. Out of 380 distributed questionnaires, 270 useful questionnaires were returned. The data were analyzed using t-test, Pearson correlation, and multiple regression. The results indicated that TV home shoppers who purchased fashion goods showed higher degree of compulsive buying than those who purchased non-fashion goods and the determinants of compulsive buying are sample＇s age, mean age of the sample＇s children, credit usage, expenditure on fashion goods, frequency of purchase of fashion goods on TV home shopping shows, and promotional tools used by TV home shopping retailers. Regarding the relative importance of the determinants, credit usage was the most influential factor followed by expenditure on fashion goods and the length of exposure to TV home shopping shows.