• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.192-194
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• 2001

회전기 고정자 권선에서 발생하는 최대 부분 방전의 연속적인 on-line 측정이 가능한 경제적이고 간단한 hybrid conversion scheme이 개발되었다. 또한 기존의 부분 방전 측정 방식인 single channel analyzer 방식, A/D 변환 방식과 대비하여 hybrid conversion scheme의 장단점이 설명되었으며, 부분 방전 측정 주파수 대역과 부분 방전 측정의 dead time의 영향을 분석하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1371-1374
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• 1997

We had developed the on-line environmental monitoring system which has installed around Kori Nuclear Power Plants and will be taken the place of the existing system. The system consists of a main computer and 11 sets of radiation monitoring post equipments. Nal(Tl) scintillation detectro was adopted in addition to ion-chamber detector and implemented with DCU(Dose Conversion Unit) and SCA(Single Channel Analyzer). Compared with the existing system, it has revised feature in the radiation measurements which are detection of artificial radioactivity and 2-ways of the radiatiion detectors. The field test trsults show that the developed radiation detecting equipments can measure environmental radiation withn 5.0% of the theoretical value.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.153-154
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• 2014

DMB 시스템은 직교주파수분할 (OFDM : Orthogonal Frequency Division Multiplexing) 기반의 전송방식을 사용하기 때문에, 단일 주파수 네트워크 (SFN : Single Frequency Network) 기반 방송망 구축이 가능하다. 이러한 SFN 방송망은 인접 송신기의 시간 및 주파수 동기, 송신소 사이의 거리, 송신 전력의 크기를 고려하여야 하며, 이를 위해서는 먼저 특정 수신점에서 채널 임펄스 응답 (CIR : Channel Impulse Response) 을 분석하여 간섭을 최소화되도록 설계하는 것이 중요하다. 본 논문에서는 DMB 시스템에서 다중경로에 의한 간섭을 효율적으로 측정하는 기법을 제안하고, 모의실험을 통해 제안된 기법의 성능을 검증하고자 한다.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.275-285
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• 2009

During an 8 month period from January to August 2007, complete blood count (CBC) samples were taken from various wards and from the outpatient department at Samsung Medical Center. In order to determine whether or not the total white blood cells were over counted, results were obtained from both the 4Diff/channel and the white blood cell channel from the automated blood analysis equipment from S company for comparison. Among patients who were on long term treatments, the number of cases determined to be over counted by comparing the WBC counts during this 8 month period was 25. Clinical chemistry tests were also conducted on the same day on the 25 samples taken. 68% of the patients showed to exceed normal range of aspartate transaminase (AST) and alanine aminotransferase (ALT) indicating abnormal liver function, and the total bilirubin range were also in excess in 60% of the total samples taken. Further clinical information which was obtained from the patients showed 98% of the patients were administered with cefepime which is the 4th generation cephalosporin at the time when the WEC were over counted. It is assumed that a multiple of factors investigated caused the over count of the WEC rather than a single factor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.86-89
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• 2009

In this paper, a broadband power line communication modem and network technology to develop tests with actual characteristics of the underground power line communication channel to be interpreted. Length and structure of the underground distribution line due to underground distribution line to the broadband powerline communication channels to measure the amount of attenuation on the signal generator, spectrum analyzer, such as contactless coupler was used to configure the channel measurement system. Demonstration tests in the test line as a single line by selecting the longest high-voltage lines where the two-channel measurement and signal attenuation on the noise level was measured. Measuring results degrade communication performance can be quite sure that was the presence of impulse noise, long lines, the line length was confirmed by the high-frequency attenuation appears.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.541-548
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• 2013

This paper presents a vector network analysis system for 2-port scattering parameters of microwave devices using some basic microwave instruments/devices such as signal generators, vector voltmeter, directional couplers and frequency mixers. The analytical model and implementation method for scattering parameter measurements - which can replace the vector network analyzers - are presented. The performance of the implemented system is evaluated through 1- and 2-port scattering parameter measurements, respectively. The vector volt signals which determine the scattering parameters are detected in two distinct methods depending on the frequency band of interests; a direct-detection method with a single signal generator and vector voltmeter for relatively low band and a heterodyne method to frequency down-mix associated with an additional signal source as well as frequency mixers for high band are used, respectively. Using these two methods, scattering parameters of UHF and X bands are evaluated and their performances are verified through a comercial vector network analyzer.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.351-354
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• 2003

We present a 12.5-GHz interleaved bidirectional ultra-dense wavelength-division-multiplexing transmission over a conventional single mode fiber of 80 km achieving spectral efficiency as high as 0.8-bit/s/Hz. The beat-frequency-locking method is used to stabilize the channel frequency within $\pm$200 MHz error. To facilitate the identification of multiple beat frequency signals, we use a radio-frequency spectrum analyzer. The bidirectional transmission penalty is about 0.3 dB compared with the unidirectional transmission over the same fiber.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.479-479
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• 2011

Flexible inverters based on complementary thin-film transistor (CTFTs) are important because they have low power consumption and other advantages over single type TFT inverters. In addition, integrated CTFTs in flexible electronic circuits on low-cost, large area and mechanically flexible substrates have potentials in various applications such as radio-frequency identification tags (RFIDs), sensors, and backplanes for flexible displays. In this work, we introduce flexible complementary inverters using pentacene and amorphous indium gallium zinc oxide (IGZO) for the p-channel and n-channel, respectively. The CTFTs were fabricated on polyimide (PI) substrate. Firstly, a thin poly-4-vinyl phenol (PVP) layer was spin coated on PI substrate to make a smooth surface with rms surface roughness of 0.3 nm, which was required to grow high quality IGZO layers. Then, Ni gate electrode was deposited on the PVP layer by e-beam evaporator. 400-nm-thick PVP and 20-nm-thick ALD Al2O3 dielectric was deposited in sequence as a double gate dielectric layer for high flexibility and low leakage current. Then, IGZO and pentacene semiconductor layers were deposited by rf sputter and thermal evaporator, respectively, using shadow masks. Finally, Al and Au source/drain electrodes of 70 nm were respectively deposited on each semiconductor layer using shadow masks by thermal evaporator. Basic electrical characteristics of individual transistors and the whole CTFTs were measured by a semiconductor parameter analyzer (HP4145B, Agilent Technologies) at room temperature in the dark. Performance of those devices then was measured under static and dynamic mechanical deformation. Effects of cyclic bending were also examined. The voltage transfer characteristics (Vout- Vin) and voltage gain (-dVout/dVin) of flexible inverter circuit were analyzed and the effects of mechanical bending will be discussed in detail.

• Journal of Marine Bioscience and Biotechnology
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• v.5 no.4
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• pp.40-45
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• 2011

Microalgae are one of the major, sustaining components of ecosystem processes and are responsible for biogeochemical reactions that drive our climate changes. Despite this, many marine microalgae are poorly described and little is known of their abundance and distribution along the coastal areas of Sooyoung Bay, Busan, South Korea. The present study has been conducted from November, 2011 to August, 2009 with the objective to provide an overview of the taxonomy diversity and abundance of microalgae along the coastal areas of the Sooyoung Bay. Water samples were collected from different sites, which were located by using a GPS tracker. Chlorophyll fluorescence of the water samples were measured by using ToxY-PAM dual-channel yield analyzer. The chlorophyll fluorescence values were relatively higher during the spring and summer and even in the region near to the sea port. Similarly the abundance of microalgae was higher near the port but diversity index had lower values. The temperature and pH values were same at all the sites. However, only the temperature varied during the sampling period, with higher values during summer and lower in winter. From the preliminary results, the following class of microalgae were found; Bacillariophyceae, Dinophyceae, Silicoflagellate and Cryptophyceae. With a future ongoing work, microalgae are being isolated to establish single cell culture and for identification using light microscopic observations, photography and molecular approaches.