• 한국통신학회논문지
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• 제21권10호
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• pp.2679-2686
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• 1996

In this paper, we propsoed the two methods to improve the conventional decision feedback interference canceller in DS/SS communication systems. The data bit is obtained by correlating the PN sequence with the received signals to the present time k, and thus the errors in the reference signal can be reduced by newly deciding all the reference signals with the resultant data bit. Additionally the cancelled signals are computed with less weight for initial reference signals of low processing gain, and highly weighted as the processing gain goes up. the resulting interference canceller outperforms the existing ones. By simulation, we found the proposed algorithm has "2-3 dB" performance gain at BER 10$^{-3}$ compared to the conventional descision feedback algorithm.algorithm.

• 음성과학
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• 제14권2호
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• pp.65-71
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• 2007

The severe-profound hearing impaired children have various disorders in everday communication due to the lack of hearing feedback. Especially, their speech produced unstable voice, omission and distortion of articulation, pitch break, cul-de-sac voice, and so on so that they were difficult to accurately deliver an intended message. This study attempts to analyze the acoustic characteristics of 4 vowel sounds produced by 35 severe-profound hearing impaired children using CSL(Computerized Speech Lab, Model 4300b). The formant data were obtained from the spectrogram and analyzed data by 12 formant filter and auto-correlation among the formants. Results showed that the hearing impaired children's formant values came out very high. They produced the vowels at the mode of hypertension with unstable voice. In order to improve their speech, they would need some adequate auditory feedback.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.70.1-70
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• 2001

Recently, research of visual control is getting more essential in robotic application, and acquiring 3D informations from the 2D images is becoming more important with development of vision system. For this application, we propose the effective way of controlling stereo vision tracking system for target tracking and calculating distance between target and camera. In this paper we address improved controller using dual-loop visual servo which is more effective compared with using single-loop visual servo for stereo vision tracking system. The speed and the accuracy for realizing a real time tracking are important. However, the vision processing speed is too slow to track object in real time by using only vision feedback data. So we use another feedback data from controller parts which offer state feedback ...

• 한국전자파학회논문지
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• 제14권4호
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• pp.330-335
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• 2003

OFDM은 무선 환경에서 고속 data 전송에 적합한 방식이다. 그러나 높은 peak-to-average power ratio(PAPR)로 인하여 비선형 왜곡의 문제점이 있다. 여러가지 PAPR 저감 방법 중에 partial transmit sequences(PTS)는 매우 유연하고 스페트럼 왜형이 발생하지 않는 좋은 방식으로 평가된다. 이 방법의 문제점은 최적화된 phase factor를 side information으로서 수신기에 전송해야만 data를 정확히 복원할 수 있다. 본 논문에서는 기존 PTS 방식에서 feedback type으로 side information을 부가하는 기법을 새롭게 제안한다. Simulation 결과를 통해 제안 방식이 종전의 PTS와 동일한 PAPR 저감 성능을 가지면서 정확하게 data를 복원하여 요구 BER을 확보할 수 있다. 또한, 제안 방식은 전송 채널 특성 변화에 무관하며, 간단히 시스템을 구성할 수 있다.

• 한국컴퓨터정보학회논문지
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• 제22권7호
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• pp.17-29
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• 2017

IRecently, researches on the recognition of indoor user situations through various sensors in a smart home environment are under way. In this paper, the case study was conducted to determine the operation of the robot vacuum cleaner by inferring the user 's indoor situation through the operation of home appliances, because the indoor situation greatly affects the operation of home appliances. In order to collect learning data for indoor situation awareness model learning, we received feedbacks from user when there was a mistake about the cleaning situation. In this paper, we propose a semi-supervised learning method using user feedback data. When we receive a user feedback, we search for the labels of unlabeled data that most fit the feedbacks collected through genetic algorithm, and use this data to learn the model. In order to verify the performance of the proposed algorithm, we performed a comparison experiments with other learning algorithms in the same environment and confirmed that the performance of the proposed algorithm is better than the other algorithms.

• 산업경영시스템학회지
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• 제41권3호
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• pp.129-137
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• 2018

VOCs have been used as the most definitive resource to reflect customer feedback when developing products and services. However, due to the development of the Internet and the emergence of SNS, VOC is no longer the only channel that represents customer opinions. There are also a number of studies showing that many customers express complaints through channels other than VOCs. In this paper, we analyze the difference between the official VOC data and the data collected through the external channel, and suggest ways to reflect the various opinions of customers. To do this, this study uses keyword analysis that can identify differences according to frequency through social network, modular analysis to distinguish topics according to centrality and similarity, and emotional analysis to confirm word polarity (positive and negative). The results of this study show that the opinions of the customers were different depending on channels such as VOCs and external channels. Therefore, the collected data through VOC as well as external channels should be used in order to reflect the opinions of customers. In particular, this paper confirms that the results of one channel may vary depending on the channel characteristics even for the same channel. This confirms that collecting voc only on certain channels may differ from what real customers require. Therefore, data collected through VOCs as well as external channels must be used to reflect various customer feedback.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권7호
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• pp.361-370
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• 2017

본 논문은 임베디드 시스템이 제어하는 서브시스템의 실시간 피드백을 반영하여 테스트 케이스를 생성할 수 있는 테스트 생성기 구조를 제안한다. 일반적으로 폐쇄형 임베디드 시스템은 자신이 제어하는 서브시스템의 피드백을 참조하여 서브시스템의 다음 상태를 제어하는 값을 결정한다. 그와 같은 시스템에서는, 피드백을 고려하지 않는 전통적인 테스트 케이스는 사용하기 어렵다. 본 논문에서 제안하는 테스트 케이스 생성기 구조는 서브시스템의 피드백을 이용하여 다음에 사용할 테스트 케이스를 실시간 재구성한다. 제안하는 구조를 구현하고 데모 시스템을 이용하여 유용성을 검증한다.

• 컴퓨터교육학회논문지
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• 제7권1호
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• pp.89-96
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• 2004

일반적으로 형성 평가는 교수-학습 활동이 진행 중에 투입되는 평가활동으로 학습 정보에 대한 피드백과 교정 및 교수 방법의 개선을 위한 평가이다. 본 논문에서는 형성평가에서 학습자 개인의 평가 결과에 따라 서로 다른 피드백을 제공하는 시스템을 제안한다. 이 시스템은 지식, 이해, 적용 등의 영역별 기준에 따라 제작된 문항을 통해 각 학습자를 평가하고 이 결과를 기반으로 구분된 학습자 유형에 따라 서로 다른 피드백을 개별 학습자에게 제공하며 학습자는 이를 통해 부족한 영역을 보완하게 된다. 교수자에게는 문항별 정답 비율뿐만 아니라 학생 개개인에게 제공되었던 피드백 내용도 알려주어 교수방법을 개선하도록 한다.

• 한국전자파학회논문지
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• 제21권10호
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• pp.1136-1142
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• 2010

본 논문에서는 조명용 LED를 광원으로 사용한 무선 광통신 시스템에서 광전 궤환을 이용한 ASK 변조 방식을 사용하여 잡음 광의 간섭을 소거하였다. 광전 궤환 회로의 발진을 이용하여 70 kHz의 반송파를 자체적으로 생성하였으며, 입력 신호를 사용하여 궤환 회로의 단락과 개방을 반복함으로써 9.6 kbps의 데이터 속도로 출력광을 ASK 변조하였다. 주변의 잡음 광이 존재하는 환경에서 광전 궤환을 이용한 ASK 변조 방식을 사용함으로써 신호대 잡음비가 약 25 dB 개선되었다.

• 대한물리의학회지
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• 제6권1호
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• pp.9-17
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• 2011

Purpose : The purpose of this study was to compare the effects of performing feedback vs repeative tasks on lower extremity motor function and falls efficacy in chronic hemiplegic patients. Methods : 40 hemiplegic patients took part in this study. The average age of the feedback-task group was 68.45 years and 68.20 in the repeative-task group. All subjects participated in the study for 8 weeks, doing exercises 3 per day per week. All participants were assessed by using the Berg balance scale (BBS), the lower-extremity subscale of the Fugel-Meyer assessment of sensorimotor impairment (FMLE), and the falls efficacy scale (FES). The data were analyzed using a paired t-test. Results : After 8 weeks of exercise training, the results of this study were: the BBS and FMLE of hemiplegic patients showed a feedback-task and repeative-task groups (p<0.05). The FES of hemiplegic patients also showed a significant difference between the quantitative-task and qualitative-task groups (p<0.05). Conclusion : We present findings suggesting that chronic hemiplegic patients could improve their standing balance ability better through a feedback-task exercise program, as opposed to a repeative-task exercise program.