• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.971-978
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• 2018

This paper deals with the design and implementation of a limiter, which is a key component of the Ku-band radar system. The limiter design with the multi-pin diode switch was complemented by wideband signal attenuation, and realized the physical implementation. In the test result of implemented limiter, when the pin diode switch is all off, it is possible to transmit the incoming signal without distortion. Also when the pin diode switch is turned on sequentially, the input signal is attenuated about 20dB or more step by step. Finally when all of them were turned on, attenuation about 50dB or more were measured for a wide bandwidth(1000MHz) in Ku-band.

• 건강소식
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• v.35 no.6
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• pp.16-17
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• 2011

음식물을 받아들여 소화하는 위장. 최대 1,500ml 정도까지 커지는 위장은 식도와 연결된 분문으로 음식물을 받아 소화시키고 잠시 저장한 뒤 유문을 통해 십이지장으로 내려보낸다. 중요한 역할을 하는 만큼 이상이 생기면 소화 불량, 더부룩함, 배탈, 속 쓰림, 설사 등 여러 증상으로 SOS신호를 보내는데, 이 같은 경고를 쉽게 무시해 버리는 게 문제다. 특히 위암은 조기에 발견하면 90% 이상 완치될 수 있으므로 정기적으로 위장을 검사해야 한다. 내시경을 넣는 위내시경검사, 조영제를 마시고 X선 촬영을 진행하는 조영촬영검사가 대표적이다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.213-216
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• 2000

퍼지제어기를 실제 플랜트에 적용할 경우, 모델링 오차와 플랜트에 대한 관련지식의 부족으로 만족할 만한 제어 결과를 기대하지 못한다. 이러한 경우 제어기 성능을 향상시키기 위해 제어인자를 다시 조정해야 하고, 이 조정과정은 시행착오방법으로 수행되기 때문에 많은 시간과 비용을 필요로 한다. 본 논문에서는 퍼지 논리를 사용하여 스케일링 계수를 자동조정하는 퍼지 레귤레이터를 제안하였다. 스케일 계수의 출력 범위와 오차, 오차 변화량 따라 퍼지 레귤레이터는 적절한 스케일링 계수값을 결정함으로써 퍼지제어기의 성능을 향상시키게 된다. 제안한 방법의 타당성을 확인하기 위해 2차 플랜트에 적용하여 모의실험을 수행하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.421-428
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• 2007

This paper discusses a fitness of the control on intersection network using fuzzy analytic hierachy process. The validity of control of traffic signal on intersection is phase, cycle of intersection. But the aigent of traffic intersection network is relative of intersection article. Therefor the aigent of traffic network intersection is before intersection passing vechile number, delayed vechile number. Fuzzy analytic hierachy process clears the grade of validity of the fixed cycle time controller and adaptive fixed cycle time and fuzzy traffic controller and proposes a new control type a traffic signal by this fuzzy analytic hierachy process.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.3
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• pp.113-120
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• 2018

In this study, we proposed a monitoring system for identifying and handling faulty sensing stream data on manufacturing equipments where low-cost sensors can be safely used. Low cost sensors will lessen the cost of implementing distributed monitoring system, but suffer from sensor noises and inaccurate sensed data. Therefore, a distributed monitoring system with low cost sensors should identify faulty signal data as either of sensor fault or machine fault, and filter out faulty signals from sensing fault. To this end, we adopted a fourier transform based diagnostic approach mixed with a weighed moving averaging method, in order to identify faulty signals. We measured how effective our approach is and found out our approach can filter out one-third faulty signals from our experimental environment. In addition, we attached wireless communication modules to reduce sensor and network installation cost. To handle massive sensor data efficiently, we employed unstructured data format with NoSQL based database.

• The Journal of the Acoustical Society of Korea
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• v.31 no.4
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• pp.205-213
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• 2012

Active acoustic array signal was measured in the East Sea and the South sea and spatial coherence was analyzed. The measurement of ambient noise, target reflection signal, sea surface backscattering signals took place including environmental measurements of sea wind, and vertical temperature profiles. The spatial coherence of ambient noise was lower than that of target reflection signal in the South Sea. The spatial coherence of target reflection signal was above 0.5 over all array length. The spatial coherence of sea surface backscattering signal was higher in high incident angle. The maximum non-dimensional array length was 3.0 ($26^{\circ}$) and 3.5 ($32^{\circ}$) to have spatial coherence above 0.5 in the East Sea. To find a design criteria for array configuration and array performance, more measurements of temporal and spatial coherence will be needed continuously in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.501-509
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• 2011

Software defined radio(SDR) has a goal that places the analog-to-digital converter(ADC) as near the antenna as possible. But current technique actually can't do analog-to-digital converting about RF band signals. So one method is studying that samples RF band signals to IF band. One of the ways Sub-Sampling technique can convert signals from RF band to IF band without oscillator. If Sub-Sampling technique is used, over 2 bands can convert signals from RF band to IF band. But due to the filter performance in RF band, it is possible to generate interference between signals that is converted in low frequency band. The effect degrades performance. In this paper, we propose one method that uses time division multiplexing(TDM) method as a solution to avoid interference between signals. By doing TDM and Sub-Sampling at the same time that method can get signals without large changes of structures.

• Journal of Korean Society of Transportation
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• v.31 no.5
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• pp.16-25
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• 2013

This study deals with the relationships between flashing operation and traffic accident at signalized intersections. The objective of this study is to analyze safety effects of the yellow flashing operation at night. In pursuing the above, this study gives particular attention to evaluating the safety results from signal operation of Cheongju's 190 signalized intersections using before-after evaluation with comparison group that are categorized by highway function. The main results are as follow. First, the numbers of traffic accidents and of fatalities/injuries in two highway types (arterial and collector road) have increased after operating the yellow flashing signal at night. Second, the numbers of accidents, fatalities/injuries, severe accidents and of fatalities/severe injuries in group A(arterial) have increased by 19%, 36%, 15% and 14%, respectively. Finally, the numbers of accidents, fatalities/injuries, severe accidents and fatalities/severe injuries in group B (collector) have increased by 50%, 64%, 41% and 77%, respectively.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.319-321
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• 2012

u-Health Care 시스템은 장기요양 환자 및 만성질환 보유자에게 의료비 절감 및 수준 높은 의료서비스를 제공 할 수 있는 방안이다. 이러한 의료 서비스를 제공하기 위해 필요한 구성으로 본 논문에선 생체신호 취득 단말기, 신호를 전송하는 스마트폰, 신호를 분석해 환자의 건강 기저선을 분석 할 수 있는 서버로 나뉠 수 있다. 본 논문에서는 이러한 환자에게서 체온, 혈압, 혈당, 산소포화도, 맥박, 심전도, 근전도에 해당하는 생체신호를 수집하는 u-Health Care 시스템을 구성하고 환자의 생체신호를 숫자형 데이터, 심전도, 근전도로 분류해 환자의 생체신호를 분석, 건강이상 상태를 파악하는 자동 분석 시스템을 구현 하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.261-264
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• 2000

음향센서의 정확도 시험을 위해서는 사전 약속된 모의신호를 발생하는 기준 음향센서, 즉 모의신호 발생기가 필요하다. 모의신호 발생기는 정확도 시험의 기준이 되므로 위치가 정확하게 산출되어야 하고, 발생시키는 모의신호는 시험 목적에 부합되도록 설계되어야 한다. 본 연구에서는 모의신호 발생기의 위치 추정 및 모의신호 발생을 위한 설계 기법을 제안하고, 제안 기법에 대한 위치 추정 알고리즘을 시뮬레이션으로 고찰한다.