• 한국음향학회지
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• 제34권2호
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• pp.91-97
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• 2015

본 논문은 스마트폰으로부터 디지털 보청기로 가청음 주파수 대역의 무선 통신을 수행한 내용을 다루었다. 반송주파수를 1 kHz 단일 채널을 사용하는 진폭편이방식에 의해 이진 데이터를 변조한 후, 정상적인 송수신 결과를 확인하였다. 전체적인 시스템 구현 과정을 상세히 설명하면서 실험 결과로 증빙해보였다. 스마트폰을 사용한 디지털 보청기 원격 제어가 가능한 실용화 제품을 실현하고자 한다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.285-289
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• 2005

In recent years, RFID is widely used in industrial applications including factory, material flow, logistics and defense areas. In this paper, we developed a RFID baseband system with ASK modulation and convolutional channel code. A commercial ASK RF module is used its frequency range in $350{\sim}351$MHz and power is 10mW and the convolution code is constraint length k=3 and rate R=1/2 The performance is measured implemented the binary search algorithm as anti-collision method and we show the wave shapes whit collision occurrence.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.487-492
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• 2003

This paper designs a Korea train identification module using a RFID system. Frequency bandwidth transmits and receives messages using the 27.095Mhz and 4.234Mhz in the ISM bandwidth. The mode of the modulation uses a transmission ASK and a receiving FSK. And it uses a reader and transponder using an active transponder. We use the loop antenna which the antenna has the directional.

• 한국통신학회논문지
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• 제9권4호
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• pp.157-162
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• 1984

무선 채널장에서의 데이터 전송은 주로 간섭과 랜덤 잡음에 의해 영향을 받는다. 디지틀 통신 시스템은 일반적인 백색 가우스성 잡음보다 임펄스성 잡음에 의한 영향이 크다. 본 논문에서는 전자간섭(EMI:electromagnetic interference)환경, 특히 임펄스성 잡음 환경하에서의 혼잡 해지는 잡음 - 주파수 변소방식열 성능을 오율의 주면에서 공명하였다.

• Nutrition Research and Practice
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• 제10권4호
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• pp.377-384
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• 2016

BACKGROUND/OBJECTIVES: Resveratrol, a natural polyphenol, has multiple functions in cellular responses including apoptosis, survival, and differentiation. It also participates in the regulation of inflammatory response and oxidative stress. MicroRNA-Let-7A (miR-Let7A), known as a tumor suppressor miRNA, was recently reported to play a crucial role in both inflammation and apoptosis. Therefore, we examined involvement of miR-Let7A in the modulation of inflammation and cell survival/apoptosis regulated by resveratrol. MATERIALS/METHODS: mRNA expression of pro-/anti-inflammatory cytokines and sirtuin 1 (SIRT1), and protein expression of apoptosis signal-regulating kinase 1 (ASK1), p-ASK1, and caspase-3 and cleaved caspase-3 were measured, and cell viability and Hoechst/PI staining for apoptosis were observed in Lipopolysaccharide (LPS)-stimulated human THP-1 macrophages with the treatment of resveratrol and/or miR-Let7A overexpression. RESULTS: Pre-treatment with resveratrol ($25-200{\mu}M$) resulted in significant recovery of the reduced cell viabilities under LPS-induced inflammatory condition and in markedly increased expression of miR-Let7A in non-stimulated or LPS-stimulated cells. Increased mRNA levels of tumor necrosis $factor-{\alpha}$ and interleukin (IL)-6 induced by LPS were significantly attenuated, and decreased levels of IL-10 and brain-derived neurotrophic factor were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. Decreased expression of IL-4 mRNA by LPS stimulation was also significantly increased by miR-Let7A overexpression co-treated with resveratrol. In addition, decreased SIRT1 mRNA levels, and increased p-ASK1 levels and PI-positive cells by LPS stimulation were significantly restored by resveratrol and miR-Let7A overexpression, respectively, or in combination. CONCLUSIONS: miR-Let7A may be involved in the inflammatory response and cell survival/apoptosis modulated by resveratrol in human THP-1 macrophages.

• 한국통신학회논문지
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• 제15권10호
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• pp.797-810
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• 1990

The error rate equations of digitally modulated signals transmitted through the Gaussian noise and tone multiple interference channel have been derived. Using the derived equations of error probabilities in the environments of Gaussian noise tone interferer and Gaussian noise multiple interferer, the error rate performances of various digitally modulated signals have been evaluated, and compared in graphs as a function of average carrier to tone interferer power ratio(CIR), average carrier to multiple interferer power ratio(CIT) and the average carrer-to-Gaussian noise powr ratio(CIR). In this paper, the modulation schemes such as amplitude shift keying (ASK), phase shift keying(PSK), frequency shift keying(FSK), minimum shift keying(MSK), quadrature amplitud modulation(QAM) and amplitude phase shift keying(APK) have been selected for the study of performance comparison. The results of comparison show us that, in low bits/sec/Hz, PSK is superior to the other schemes, but in high bits/sec/Hz, mixed multi ary type is better than single multi ary type. And in strong noise evironment, the multiple interferer has much influence than tone interferer, however, in low noise environment. the mojor error factor is tone interferer. But tone interference effect nearly disappears over specified CIR level about 20[dB]. And the modulation schemes using amplitude are heavily influenced by multiple interference.

• 디지털콘텐츠학회 논문지
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• 제7권3호
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• pp.169-174
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• 2006

RFID는 각종 서비스 산업은 물론 물류, 산업 현장, 제조 공장과 물품의 흐름이 있는 곳이면 어디에서나 적용이 가능하여 사회 여러 분야로부터 큰 관심을 받고 있다. 하지만 현재 900Mhz 대역의 RFID에서 사용하는 ISO/IEC 18000-6의 프로토콜에서는 에러검출을 위한 CRC16만을 사용하여, 에러정정능력을 갖추지 못해 그 신뢰성이 떨어질 것으로 여겨진다. 본 논문에서는 이러한 RFID 시스템의 신뢰성 향상을 위해 Reader에서 Tag로의 명령어 및 데이터 전송 시에 콘벌루션 부호를 적용하여 시스템의 신뢰성 향상을 목적으로 하며, 이런한 방식을 적용했을 때와 적용하지 않았을 때의 에러율을 측정 비교하였다.

• 한국음향학회지
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• 제27권7호
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• pp.342-349
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• 2008

수중통신 시 다중 음파 경로의 생성은 명확한 메시지전송을 어렵게하는 원인중 하나이다. 본 논문에서는 이러한 문제점의 해결을 위하여 각기 다른 경로에 따라 형성된 다중 경로간의 지연 시간을 계산하여 변조주파수변환구간을 생성하는 방법을 제안하였다. 송신단에서는 생성된 변조주파수변환구간의 크기에 따라 메시지를 분할하여 두 개의 주파수를 사용하여 QPSK(Quadrature Phase Shift Keying)방식을 교대로 호핑하여 메시지를 전송 하였다. 이에 대응하여 수신단에서는 수신된 메시지를 알고리즘 설계 시 구축한 프로토콜에 의하여 복조하여 원신호로 복원하는 적응 BISMO 알고리즘을 제안 하였고 모의실험을 통하여 적응적 변조주파수변환구간, 추정 오류율을 계산하였다.

• 한국ITS학회 논문지
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• 제10권3호
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• pp.79-84
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• 2011

본 논문에서는 ITS 응용을 위한 Alamouti 기법을 이용한 효과적인 차량 검출 성능을 분석하였다. 차량 검출은 DSRC (Dedicated Short Range Communication) 기반의 하이패스 환경에서 실험하였다. 시스템 성능으로는 비트 에러 확률로 실험 결과 값에 대하여 분석하였으며, 실험환경은 진입차량의 속도를 60km/h로 가정하여 DSRC 기반의 변조방식인 ASK 기법 을 적용하여 실험하였다. 또한 적용된 채널은 Rician 채널을 적용하여 LOS (Line of Sight)환경을 고려하며 실험을 하였다. 또한 사용된 반송파 주파수는 일본 DSRC 시스템 하향링크를 참고하여 5.8GHz를 적용하였다. 실험결과로 안테나가 2개일 경우와 Alamouti 기법을 적용할 때의 검출성능을 각각 나타내었으며, Alamouti 기법을 적용할 때 성능이 보다 개선되었음을 본 실험을 통해 알 수 있었다.

• Journal of Biosystems Engineering
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• 제27권5호
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• pp.459-466
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• 2002

In Korea, a need of automatic dairy farm management system has been increased to lower production cost and to strengthen international competition. However, the present management system was mostly relied on foreign technologies and caused some problems in post management and after-sales services. Therefore, though there is a problem of price and quality at present, domestic technologies of the management system should be developed for the long run. This study was conducted to develop an electronic identification unit for an automatic dairy farm management system. The developed system was consisted of a tag, a reader, a switching circuit, and a personal computer. The tag attachable to each individual cow was developed to transmit individual radio frequency(RF) code into the air with modulation of ASK(amplitude shift keying). And the switching circuit was added to avoid confusion on reception and transmittance. The reader attached to a feeding device was developed to transmit activating signal periodically and to identify code of the individual tag when the tag was approached to the device. The reader was consisted of an active filter, a detecter, a comparator and a microcontroller. The test result was feasible enough to apply it for the automatic farm management system and the identified maximum distance was about 37cm.