• 한국환경복원기술학회지
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• 제11권3호
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• pp.74-86
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• 2008

To assessment the disturbances of the Namgang caused by dam construction, upstream area was selected for the reference reach and downstream area was selected for the comparison reach. And these reaches were surveyed and analyzed according to the assessment criteria of the river disturbances.The artificial factors of river disturbances were classified as river improvement works, dam construction and aggregate dredging. The indexes were physical factors as like epifaunal (bottom), embeddedness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection, riparian zone etc.The assessment results showed 46% of the assessment criteria which was serious status in dam downstream area and 89.5% of it which was excellent status in dam upstream.Finally, the results showed that physical river environment in downstream area was disturbed by the discharge control and the interception of sediment discharge by dam, consequently this disturbance give rise to impact of ecosystem in river.

• 한국통신학회논문지
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• 제41권11호
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• pp.1341-1348
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• 2016

본 논문은 합법적 수신자와 불법적인 도청자가 함께 존재하는 Wire-Tap 채널 모델 하에서 HT-STBC (Hadamard Transformed-Space Time Block Codes)와 인위적 잡음 (Artificial Noise)을 이용한 보안 성능 향상 방법을 제안한다. 기존의 STBC와 인위적 잡음을 이용한 방법은 QPSK 이상의 변조 방식을 사용했을 때 수신자와 도청자 사이의 BER (Bit Error Rate) 차이가 제한적으로 증가하는 문제가 있다. 이를 해결하기 위해 Hadamard 변환과 STBC를 결합한 HT-STBC와 인위적 잡음을 이용하여 수신자의 BER을 기존 방법보다 감소시키고 수신자와 도청자 사이의 BER 차이 또한 증가함을 모의실험을 통해 입증하였다. 모의실험 결과, 본 논문에서 제안한 방법을 이용하면 기존의 STBC와 인위적 잡음을 이용한 방법에 비하여 약 3dB의 성능이 향상됨을 확인하였다.

• Molecules and Cells
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• 제23권3호
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• pp.363-369
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• 2007

Mitochondria play a central role in energy-generating processes and may be involved in the regulation of channels and receptors. Here we investigated TRPM7, an ion channel and functional kinase, and its regulation by mitochondria. Proton ionophores such as CCCP elicited a rapid decrease in outward TRPM7 whole-cell currents but a slight increase in inward currents with pipette solutions containing no MgATP. With pipette solutions containing 3 mM MgATP, however, CCCP increased both outward and inward TRPM7 currents. This effect was reproducible and fully reversible, and repeated application of CCCP yielded similar decreases in current amplitude. Oligomycin, an inhibitor of $F_1/F_O$-ATP synthase, inhibited outward whole-cell currents but did not affect inward currents. The respiratory chain complex I inhibitor, rotenone, and complex III inhibitor, antimycin A, were without effect as were kaempferol, an activator of the mitochondrial $Ca^{2+}$ uniporter, and ruthenium red, an inhibitor of the mitochondrial $Ca^{2+}$ uniporter. These results suggest that the inner membrane potential (as regulated by proton ionophores) and the $F_1/F_O$-ATP synthase of mitochondria are important in regulating TRPM7 channels.

• 한국수자원학회논문집
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• 제45권2호
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• pp.127-136
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• 2012

하천은 다양한 환경조건에 따라 변화될 수 있는 공간으로 하천복원을 설계하기 위해서는 현재 하도의 안정성 여부를 파악할 수 있는 하도 평가가 필요하다. 하도 평가는 대상하천의 지형 및 수리 수문 등 다양한 정보가 요구되지만 국내여건상 과거자료 미비로 인해 시 공간적으로 변화된 하천의 지형학적 정보를 파악하기에는 많은 어려움이 있다. 본 연구는 만경강의 과거에서 현재까지의 하도지형 변화를 평가하기 위한 방안으로 영상분석기법을 이용하여 구하도 형성, 하도 종 횡단 변화, 하도 내 미지형 변화 등을 분석하였다. 만경강의 경우1920, 30년대 직강화 공사로 하도길이가 약15 km가 줄었으며, 하도가 절단되는 과정에서 6개소의 구하도 구간이 형성되었다. 이후 만경강은 하도경사 조정과 물이용을 위해 지속적인 보의 설치가 증가되었다. 보의 설치는 저수로 폭, 최심선 길이, 식생사주, 모래사주, 전체 사주 및 수역면적 등 변화의 주요원인이 되었다. 만경강 하도는 현재 하류구간에서 안정하도를 유지하는 것으로 판단되나 중류와 상류 구간 하도는 안정하도에 도달하지 못한 것으로 판단된다.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.125-134
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• 2004

The improvement of artificial respiration method has brought about the decrease in mortality of pulmonary diseases patients. Various respiratory curative methods, inclusive of HFOV (High Frequency Oscillatory Ventilation), have been developed for more effectual and less harmful management of acute respiratory failure. However, the mechanism of gas transfer and diffusion in a bronchiole has not yet been clarified in detail. As a first approach to the problem, we measured oscillatory flows in a Y-shaped micro-channels as bronchiole model by micro Particle Image Velocimetry(micro PIV). In order to establish the fundamental technique of PIV measurements on oscillatory air flow in a micro-channel, we used about 500-nm-diameter incense smoke particles, a diode laser, a high speed camera including an objective lens, and a HFOV, which is effective technique for medical care of pulmonary disease patients, especially, infants. The bronchiole model size is that parent tube is $500\{mu}m$ width and $500\{mu}m$ depth, and daughter tubes are $450\{mu}m$ width and $500\{mu}m$ depth. From this study made on the phenomenon of fluid in micro size bronchus branch of a lung, we succeeded to get time series velocity distribution in a micro scale bronchial mode. The experimental results of velocity distribution changing with time obtained by micro PIV can give fundamental knowledge on oscillatory airflow in micro-channel.

• 한국물환경학회지
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• 제22권1호
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• pp.150-158
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• 2006

Over the past few years, many studies have been conducted on the flow, sediment movement, pollution transportation and scour etc. However, very few attempts have been made at the hydraulic studies reflecting upon the ecological function. The objective of this study is to examine the structures of the flow and turbulence in an open circular channel and their relationship to distribution of the organisms and chironomids. Under different flow conditions, the organic matter and some chironomids were injected into the channel. Using the obtained velocity data, the flow mechanisms and the turbulent shear stresses were analyzed. Organic matters and chironomids were distributed on the region that the velocity was slower and the turbulent shear stresses were smaller. Some habitat moved even though chironomids were inhabited. This phenomenon has relationship with the flow mechanism. Some chironomids have distributed around the habitat structure of a hemisphere. The secondary flow has affected the deposition of the organic matters and the distribution of chironomids.

• 융합신호처리학회논문지
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• 제5권1호
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• pp.13-17
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• 2004

망막 촬영 및 다채널 고속 영상 획득 시스템을 개발하였다. 망막 두께 측정은 망막을 3차원으로 촬영하고 고속으로 신호처리를 할 수 있는 시스템을 요구한다. 망막에 레이저를 투사한 후에 반사되어 돌아오는 레이저의 양을 array photo diode를 이용하여 감지하며 이를 3차원 영상화하여 망막의 두께를 측정할 수 있다. 망막에 레이저를 투사하는 장치, APD 광센서를 이용한 망막 영상화 장치, 다채널 고속 A/D 변환장치 및 PCI 인터페이스를 개발하였다. polygon mirror와 galvano mirror를 이용하여 HeNe 레이저 빔을 각각 수평방향과 수직방향으로 주사하여 이미지 평면을 만들어 망막에 투사하였다. APD 어레이 광센서를 이용하여 각 층별로 나타나는 망막영상을 획득하였으며, 이를 실시간으로 A/D 변환하여 PCI 버스를 통해 컴퓨터로 전송하였다.

• 전기학회논문지
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• 제67권6호
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• pp.759-766
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• 2018

Although the Act on the Prevention of Light Pollution Due to Artificial Lighting has been enforced since 2013, the area of advertisement lighting has made slow progress in solving the problems of light pollution. This paper first investigated institutional problems by analyzing domestic laws and regulations relating to the light pollution of advertisement lighting, and investigated and analyzed methods for reducing light pollution that were applied in overseas countries. Then, problems of light pollution were analyzed by conducting a research on the actual status of advertisement lightings installed in South Korea and applying various methods for reducing light pollution, and advertisement lighting using LED was recommended. As a method for reducing light pollution that can be applied to the process of manufacturing channel letter-type advertisement lights, power consumption per unit area ($W/m^2$) was proposed, and $100W/m^2$ was recommended as a value currently suitable for South Korea.

• 한국컴퓨터정보학회논문지
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• 제13권5호
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• pp.111-116
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• 2008

레이더 시스템은 간섭채널에서 목표물을 신속, 정확하게 예측하여야 한다. 무선채널의 간섭요소로는 인공구조물, 자연구조물에 의해서 다중경로가 형성되어 신호의 추정이 어렵다. 이러한 간섭신호를 제거하기 위해서 디지털 빔형성, 적응배열안테나 등 많은 연구가지속 되어왔다. 본 논문에서는 적응배열 안테나와 코히어런트 간섭신호를 제거하는 SPT-SALCMV 빔형성 알고리즘을 제안하였다. 적응 배열은 간섭신호의 방향에 대해서는 널 패턴을 형성하여 이득을 감소시킨다. 그리고 표적신호 방향으로는 빔 패턴의 이득을 일정하게 유지함으로서 원하는 신호를 추정한다. 본 논문에서 제안한 SPT-SALCMV 알고리즘은 목표물에 대한 위치를 정확히 수신하였다. 그러나 기존의 SPT-LCMV 알고리즘은 약 30 정도의 빔 오차가 생겼다. 따라서 본 논문에서 제안한 SPT-SALCMV 알고리즘이 기존의 SPT-LCMV알고리즘보다 우수함을 입증하였다.

• International journal of advanced smart convergence
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• 제10권1호
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• pp.75-81
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• 2021

As the number of connected smart devices and applications increases explosively, the existing orthogonal multiple access (OMA) techniques have become insufficient to accommodate mobile traffic, such as artificial intelligence (AI) and the internet of things (IoT). Fortunately, non-orthogonal multiple access (NOMA) in the fifth generation (5G) mobile networks has been regarded as a promising solution, owing to increased spectral efficiency and massive connectivity. In this paper, we investigate the achievable data rate for non-orthogonal multiple access (NOMA) with negatively-correlated information sources (CIS). For this, based on the linear transformation of independent random variables (RV), we derive the closed-form expressions for the achievable data rates of NOMA with negatively-CIS. Then it is shown that the achievable data rate of the negatively-CIS NOMA increases for the stronger channel user, whereas the achievable data rate of the negatively-CIS NOMA decreases for the weaker channel user, compared to that of the positively-CIS NOMA for the stronger or weaker channel users, respectively. We also show that the sum rate of the negatively-CIS NOMA is larger than that of the positively-CIS NOMA. As a result, the negatively-CIS could be more efficient than the positively-CIS, when we transmit CIS over 5G NOMA networks.