• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.123-130
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• 2007

In this paper, the design requirement and the electrical circuit analysis are performed to construct the multi-channel cardiac activation pre-amplifier necessary for a signal conditioning circuit. The general 64 channel configuration is expanded into 128 channels to enhance the spatial resolution on the mapped surface of the heart. The 128 channels pre-amplifier consists of input circuit, differential amplifier, right leg driven circuit and main-amplifier with notch filter part.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.723-726
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• 2011

전 세계적으로 사회기반시설 및 신재생 에너지 생산을 위한 공간부족 문제를 해결하기 위하여 초대형 부유구조물에 대한 관심이 증가하고 있다. 다양한 사용분야에 대한 안정성 확보를 위해 파랑하중에 의한 동적 응답과 부유체의 강성 대비 길이 효과로 인해 발생할 수 있는 특이 거동에 대한 분석이 필요하다. 초대형 부유구조물의 경우 중앙부에 비해 양끝 단에서 과도한 응답이 발생하며, 이를 해결하기 위해 입사파가 들어오는 초대형 부유구조물의 단부에 부착되는 다양한 감요장치(anti-motion device)가 제안되어지고 있다. 초대형 부유구조물에 감요장치가 적용될 경우 입사파에 의한 동적 파압을 감소시켜 구조물의 전반적인 응답을 줄여줄 수는 있지만 감요장치의 질량이 클 경우 오히려 끝단의 응답을 증폭시킬 수 있다. 본 논문에서는 양단 자유 경계조건의 탄성지지된 보를 이용하여 초대형 부유구조물의 길이와 끝단에 부착된 감요장치의 질량으로 인한 영향을 분석하였다.

• Korean Architects
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• s.594
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• pp.170-181
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• 2018

국립현대미술관은 김중업건축박물관과 공동주최로 건축사 김중업을 조명하는 '김중업 다이얼로그'전을 8월 30일부터 12월 16일까지 국립현대미술관 과천 중앙홀과 2전시실에서 열고 있다. 그가 설계한 30여 년간의 건축물과 관련된 사진과 자료 3000여 점이 전시중이다. 전시는 학예연구사의 안목과 해석작업이 중요하다. 역사와 문화라는 재료를 요리하는 학예연구사의 안목에 따라 그 가치가 빛나거나 그 반대일 수 있는데, 이런 이유로 학예연구사는 전시기획에 대한 권한을 갖고 역사해석, 전시방법 선택 등을 하게 된다. 정다영 학예연구사는 2011년부터 국립현대미술관의 건축부문 학예연구사로 일해 왔다. 올해 베네치아 건축 비엔날레 한국관 공동 큐레이터로 참여해 '스테이트 아방가르드의 유령'전을 기획했으며, 이번 '김중업 다이얼로그'전도 그의 작품이다. 월간 '공간'에서 약 6년간 기자생활을 하고, 학예연구사의 길을 걷고 있는 그녀는 전시라는 매체를 통해 건축의 영역과 담론을 확장 증폭시켜 관계를 맺고 퍼트리는 어쩌면 당대 건축계에 가장 필요한 일을 해주고 있다.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.37.5-38
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• 2010

경희대학교 우주탐사학과에서는 우주공간 탐사를 위해 Trio(TRiplet Ionospheric Observatory)-CINEMA(Cubesat for Ions, Neutrals, Electrons and MAgnetic fields)로 명명된 초소형 위성을 개발하고 있다. 과학임무는 지구 저궤도에서 고에너지 입자를 관측하는 것이며, 이를 위해 고에너지 (2~300keV) 입자 검출기와 자기장 측정기가 탑재된다. 저에너지 입자 검출기 시스템인 STEIN(SupraThermal Electrons, Ions, Neutrals)은 $1\times4$ Array의 개선된 실리콘 검출기와 이온, 전자, 중성입자를 분리할 수 있는 정전장 편향기, 그리고 신호를 처리하는 전자회로로 구성되어있다. 설계된 전자회로는 매우 작은 검출기 기판, 아날로그 기판과 디지털 기판으로 이루어져 있고, 475mW 이하의 저 전력으로 동작한다. 또한 2~100keV의 에너지를 1keV이하의 해상도로 30,000event/sec/pixel 까지 관측 할 수 있도록 회로를 설계하였다. 센서로 들어온 입자로 인해 발생한 펄스의 신호는 4개의 아날로그 회로가 담당하게 되는데, Folded cascode amplifier를 배치하여 증폭률을 높인 Charge sensitive amplifier를 통해 신호를 증폭하고, $2{\mu}s$ unipolar gaussian shaping amplifier를 통해 읽기 쉽게 처리된 신호를 상한파고선별기와 하한파고 선별기를 통해 유효 값 여부를 판단하고, 피크 검출기를 통해 피크의 타이밍을 측정한 뒤 신호를 아날로그-디지털 변환 회로를 통하여 8bit의 값으로 나타내어, 입자들의 Spectrum을 측정하게 된다. 크기와 소비전력이 적음에도 검출성능이 우수하기 때문에 이 시스템은 향후 우주탐사 시스템에 있어 매우 중요한 역할을 수행 할 것으로 생각한다.

• Journal of IKEEE
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• v.22 no.4
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• pp.953-958
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• 2018

In this study, a portable detection system was developed that can detect harmful gas and signals simultaneously in an enclosed space of industrial sites and underground facilities. The developed system is a sensor module for gas detection, a patch type 1 channel small ECG sensor, a module for three-axial acceleration detection sensor, and a system for statistics. In order to verify the performance of the system modules, the digital resolution, signal frequency, output voltage, and ultra-small modules were evaluated. As a result of the performance of the developed system, the digital resolution was 300 (rps) and the signal amplification gain was 500 dB or more, and the ECG module was manufactured with $50mm{\times}10mm{\times}10mm$ to increase patch utilization. It is believed that the product of this research will be valuable if it is used as an IoT-based management system for real-time monitoring of industrial workers.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.619-633
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• 1996

Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 495-50N. Especially, in order to investigate the intraseasonal interaction of last Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement-and the evolution of the large-scale connections are studied. To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to sastward but this mode was detected as the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40~50days.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.99-105
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• 2022

We have evaluated the performance of an all-optical automatic gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) to suppress the optical signal fluctuation induced by atmospheric turbulence in terrestrial free-space optical communication systems. In our measurements, the input power into the EDFA was set to be -30 dBm and -10 dBm to operate the amplifier in the small-signal and saturation regions, respectively. The fluctuations in the optical signal were emulated with an acousto-optic modulator driven with a sinusoidal voltage. From the measured results, we have found that an all-optical AGC EDFA could suppress the optical signal fluctuation effectively, as long as the EDFA operated in the small-signal region with a high feedback amplified spontaneous emission (ASE) power.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.35-43
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• 2022

In this paper, a study was conducted to produce 20W by combining a 10W MMIC and raising the unit power amplifier to 100W SSPA by combining the 8-way spatial coupler. SSPA requires low-loss, high-efficiency coupling techniques to meet high output with the output of a single element relatively low compared to TWTA. Designed and produced in this paper, the SSPA was manufactured as a 100W SSPA by mounting eight 20W high-power amplification modules in an 8-way spatial coupler with a reflection loss of 20dB or more and an excellent coupling efficiency of 94% or more. When -10dBm was applied, it was 112.2~169.8W at 20kHz 20%, 125.9~173.8W at 400kHz 40%, 117.5~162.2W at 800kHz 40%, showing performance of over 60dB and over 100W in all three PRF conditions.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.15-23
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• 2009

The site effects relating to the amplification of ground motion under earthquake loading are strongly influenced by both the subsurface soil condition and geologic structure. In this study, the site effects at the Hongseong area in Korea were examined by both the site investigation including borehole drilling and in-situ seismic tests and the site visit for acquiring geologic information of ground surface. Subsurface of Hongseong area with a major instrumental earthquake event in 1978 is composed of weathered layers of a maximum of 45 m thickness overlying bedrock. A geotechnical information system based on GIS framework was implemented to effectively find out spatial geologic structure of study area and it indicated Hongseong is a shallow and wide shaped basin. Two-dimensional finite element (FE) analyses for a representative cross-section of the Hongseong area were performed to evaluate seismic site responses. From the results of seismic responses, it was observed that the ground motions were amplified during the propagation of shear waves through the soil layer overlying the bedrock and the duration of shaking near the basin edges was prolonged due to the surface waves generated by interactions of shear waves with basin geometry. Furthermore, one-dimensional FE seismic response analyses were additionally conducted for soil sites selected in the basin, and it gives similar results to the two-dimensional seismic responses at most locations in the basin with the exception of the locations near the basin edges, because the basin in this study is very shallow and wide.

• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.5-19
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• 2009

Most of earthquake-induced geotechnical hazards have been caused by the site effects relating to the amplification of ground motion, which is strongly influenced by the local geologic conditions such as soil thickness or bedrock depth and soil stiffness. In this study, an integrated GIS-based information system for geotechnical data, called geotechnical information system (GTIS), was constructed to establish a regional counterplan against earthquake-induced hazards at an urban area of Daejeon, which is represented as a hub of research and development in Korea. To build the GTIS for the area concerned, pre-existing geotechnical data collections were performed across the extended area including the study area and site visits were additionally carried out to acquire surface geo-knowledge data. For practical application of the GTIS used to estimate the site effects at the area concerned, seismic zoning map of the site period was created and presented as regional synthetic strategy for earthquake-induced hazards prediction. In addition, seismic zonation for site classification according to the spatial distribution of the site period was also performed to determine the site amplification coefficients for seismic design and seismic performance evaluation at any site in the study area. Based on this case study on seismic zonations in Daejeon, it was verified that the GIS-based GTIS was very useful for the regional prediction of seismic hazards and also the decision support for seismic hazard mitigation.