• 천문학회보
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• 제39권1호
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• pp.45.1-45.1
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• 2014

We present the results of a time series analysis of the long-term radio lightcurves of four blazars: 3C 279, 3C 345, 3C 446, and BL Lacertae. We exploit the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) monitoring program which provides densely sampled lightcurves spanning 32 years in time in three frequency bands located at 4.8, 8, and 14.5,GHz. Our sources show mostly flat or inverted (spectral indices -0.5 < alpha < 0) spectra, in agreement with optically thick emission. All lightcurves show strong variability on all time scales. Analyzing the time lags between the lightcurves from different frequency bands, we find that we can distinguish high-peaking flares and low-peaking flares in accord with the classification of Valtaoja et al. (1992). The periodograms (temporal power spectra) of the observed lightcurves are consistent with random-walk powerlaw noise without any indication of (quasi-)periodic variability. The fact that all four sources studied are in agreement with being random-walk noise emitters at radio wavelengths suggests that such behavior is a general property of blazars.

• 방송공학회논문지
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• 제8권3호
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• pp.228-237
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• 2003

이동멀티미디어방송 시스템의 기본 시스템을 이루는 유럽 방식인 Eureka-147 디지털 오디오 방송 시스템의 기본 요구 사항은 컴팩트 디스크와 같은 음질을 목표로 하므로 요구 비트오류률 ${10}^{-4}$을 기준으로 설계가 이루어졌다. 이동멀티미디어방송 시스템은 오디오 중심의 Eureka-147 디지털 오디오 방송 시스템과 달리, 멀티미디어 서비스를 중심으로 설계가 이루어져야 하기 때문에 요구 비트오류확률은 ${10}^{-7}$∼${10}^{-8}$ 이하를 요구한다. 이를 위하여 기존의 Eureka-147 디지털 오디오 방송 표준에 대한 호환성을 유지하면서 이동멀티미디어방송에 대한 요구 비트오류율을 만족하기 위한 방법으로 RS(Reed-Solomon) 부호와 길쌈 인터리버를 조합한 외부호화채널부호화 방식을 추가적으로 도입한다. 본 논문에서는 채널부호화 방식을 추가하였을 경우의 이동채널 모델을 기반으로 이동멀티미디어방송 시스템에 대한 채널 성능을 시뮬레이션하며, 시뮬레이션 결과로부터 채널부호화 추가의 필요성 및 적합성을 분석한다.

• 전기의세계
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• 제29권12호
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• pp.798-803
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• 1980

A computer program for noise analysis of the audio circuit is developed. The application of the program to the equalizer, low frequency amplifier of radio circuit and cascaded amplifier show good results. The general noise analysis method for cascade operational amplifier is presented. The noise spectral power density is calculated for a resonator active filter.

• 보건교육건강증진학회지
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• 제19권3호
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• pp.35-49
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• 2002

The purpose of this study is to provide an effective program contents of information supplied by broadcasting media with the aim of developing health program models. Health programs which have been aired and are being aired on KBS I radio, KBS, EBS, Cable TV and SBS radio were analyzed in order to understand the issues of current health programs and to design a plan for improvement. In order to address current issues of health programs, the range of health information should be extended to meet various expectations from the public audience, in addition to dealing with diagnosis and treatment of illnesses. Programs should be capable of encompassing various issues such as health practice, prevention, information on medical facilities, public health policies, daily health information, and the role of patients. As health programs function as major information sources for health services, it is necessary to raise the quality and credibility of broadcasting. Broadcasting agencies has a responsible role for public health promotion through health programs. In order to make it possible for broadcasting to fulfill its social responsibility, it is advisable to develop programs that have a clear understanding of what is the cognition of the public and the level of demand in regard to health programs.

• 대한전기학회논문지:전력기술부문A
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• 제55권4호
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• pp.151-155
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• 2006

HVAC transmission lines must be designed to satisfy environmental regulations. Therefore it is necessary to pre-evaluate environmental problems for transmission line designer using prediction program. In this study, environmental design software, TLCALC(Transmission Line CALCulation) for transmission lines was developed as a comprehensive window program. It has 6 modules that are audible noise, radio noise, television noise, magnetic field, electric field and conductor surface gradient. TLCALC solved a few problems in use of the existing foreign tools and took several advantages as follows; (1) It is a common tool that solves calculating limitations of foreign formulas, (2) It has wide application ranges and enhances accuracy of prediction. (3) It can be applied to almost transmission line configurations in Korea. (4) Experienced designers can get the results of calculation within about 15 minutes. Because the use of TLCALC is easy and practical, this program will be usefully applied to the environmental friendly design and construction of transmission lines. In the future, it is expected that public complaints and social environmental cost will be reduced by the use of TLCALC.

• 천문학논총
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• 제32권1호
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• pp.271-273
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• 2017

The AKARI North Ecliptic Pole Deep Field is a natural location to accomplish deep extragalactic surveys. It is supported by comprehensive ancillary data extending from radio to X-ray wavelengths, which have been used to classify radio sources as radio-loud and radio-quiet objects and to create a catalogue of Active Galactic Nuclei (AGN). This has been achieved by using a radio-optical classification and colour-colour diagrams rather than the more usual way based on spectroscopy Furthermore, we explore whether this technique can be extended by using a far-Infrared (FIR) colour-colour diagram which has been used to identify 268 high redshift candidates.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1826-1829
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• 2005

Recent advancement in wireless communications and electronics has enabled the development of low power sensor network. Wireless sensor network are often used in remote monitoring control applications, health care, security and environmental monitoring. Wireless sensor networks are an emerging technology consisting of small, low-power, and low-cost devices that integrate limited computation, sensing, and radio communication capabilities. Sensor network platform for health care has been designed, fabricated and tested. This system consists of an embedded micro-controller, Radio Frequency (RF) transceiver, power management, I/O expansion, and serial communication (RS-232). The hardware platform uses Atmel ATmega128L 8-bit ultra low power RISC processor with 128KB flash memory as the program memory and 4KB SRAM as the data memory. The radio transceiver (Chipcon CC1000) operates in the ISM band at 433MHz or 916MHz with a maximum data rate of 76.8kbps. Also, the indoor radio range is approximately 20-30m. When many sensors have to communicate with the controller, standard communication interfaces such as Serial Peripheral Interface (SPI) or Integrated Circuit ($I^{2}C$) allow sharing a single communication bus. With its low power, the smallest and low cost design, the wireless sensor network system and wireless sensing electronics to collect health-related information of human vitality and main physiological parameters (ECG, Temperature, Perspiration, Blood Pressure and some more vitality parameters, etc.)

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.19-25
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• 2015

In this time, as an industrial society developed to a welfare society, more and more people want their quality of lives upgraded and specially customized service by mass production/mass consumption. And it leads to an increase of requiring service. There're active developments and studies on various IT equipment as the requirement made IT devices used in service. In this paper, we try to design and realize radio paging DID by using smart device to be used as a receiver of a radio pager which is broadly used at face to face service. Firstly, we used MCU to design and implement Wireless Calling Gateway which change radio calling signal of ISM band to smart device. A receiver of wireless caller used original receiver module. Also it used bluetooth module to communicate with smart device. It was possible to have satisfactory communication since radio paging signal converter and smart device were linked in 3M. Secondly, to indicate various paging information delivered from a radio pager, we realized DID application program by using Smart PAD. As a result, we could indicate various information compared to an original receiver which only could indicate letters or numeric data. Secondly, we implemented the DID app for wireless calls that can display a variety of information sent from a wireless pager. Was implemented using the Smart Pad. As a result, it is shown that can display a variety of information than the existing receiver.

• 한국컴퓨터정보학회논문지
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• 제12권4호
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• pp.149-158
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• 2007

급변하는 미디어 환경에서 라디오가 보편적 서비스를 제공하는 매체로서 경쟁력을 갖기 위해서는 디지털로의 전환이 요구되고 있다. 특히, 중파방송의 경우 대부분의 매체가 FM대역에서 표준 FM으로 동일한 내용의 프로그램으로 방송을 실시하고 있어서 전환 효과가 더 미흡할 것으로 예측된다. 그러나 라디오 매체는 이동성, 개인성, 현장성, 광역성, 즉시성, 공익성이 강한 매체 특성을 갖고 있어서 앞으로도 지속적으로 서비스가 이루어지기 위해서 라디오 매체의 미래에 대한 연구가 필요한 시점이며, 매체별 균형 발전이라는 논의의 중심은 라디오의 디지털화가 트렌드가 될 것이다. 또한 라디오는 타 매체에 비하여 전환에 따르는 비용이 적고, 용이한 측면이 있다. AM방송은 가장 먼저 방송을 개시 매체로 전국 네트워크가 구축되어 있으며, 수신기 또한 가장 많이 보급되어 있는 매체로서 전국 어디에서나 방송을 청취할 수 있는 큰 장점이 있다. 본 논문은 오늘날 디지털 기술의 발전으로 모든 미디어가 디지털로 빠르게 전환되고 있는 상황에서 디지털 전환이 이루어지고 있지 않은 AM방송을 디지털로 전환할 때 어떠한 서비스 모델이 적합한가를 문헌 조사자료와 KBS의 실험결과를 바탕으로 제안코자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.1117-1124
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• 2005

주파수 대역에 따른 전파의 전파환경은 현저하게 다르므로 통신환경도 VHF대는 직접파에 의하며 HF대는 대부분 전리층 반사파에 의한다. 우리나라 연근해역의 비SOLAS 선박들의 해상통신은 선박안전법 시행규칙에 의하며 선박들은 지정된 무선설비를 탑재 하여 통신을 수행하게 된다. 본 논문에서는 VHF 및 HF 무선전화에 의하여 해상통신을 수행하는 연근해 선박들의 통신환경을 조사하고자 전파환경 시뮬레이션 프로그램을 활용하여 분석하였다. 그리고 연안 선박들의 현행 무선설비 탑재기준에 맞추어 분석된 자료를 근거로 전파환경과 통신현황을 예측하였으며, 관련규정을 합리적으로 개선시켜 나가는 방안과 VHF 해안국간의 네트워크 통합에 대한 필요성을 제시하였다.