• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.3
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• pp.144-151
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• 2012

Chronic gastritis is the disease that is occuring in one in every 10 persons in Korea. In western medicine, endoscopy is needed to diagnose chronic gastritis, but it causes patients a pain and budget of expense. According to the TEM (Traditional Eastern Medicine), on the other hand, the 'Guan' position of the right wrist is related to a stomach. Thus we can diagnosis chronic gastritis by analyzing of pulse signal. However, pulse signal diagnosis is depended on oriental doctor's knowledge and experience. In this study, a systematic approach is proposed to analyze the computerized pulse signal. The pulse signals are firstly pre-processed, Gaussian model is adopted to fit the pulse signal, and then some related parameters are extracted from the model. Consequently, disease-sensitive parameters are selected by T-test and statistical difference. Finally, the selected parameters are entered into a Fuzzy C-Means (FCM) algorithm for classification. Classification results show that healthy persons and chronic gastritis patients are 95% and 87%, respectively.

• Korean Journal of Remote Sensing
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• v.15 no.1
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• pp.39-50
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• 1999

It is complicate and time-consuming process to classify a multi-band satellite imagery according to the application. In addition, classification rate sensitively depends on the selection of training data set and features in a supervised classification process. This paper introduced a classification network adopting a fuzzy-based $\gamma$-model in order to select a training data set and to extract feature which highly contribute to an actual classification. The features used in the classification were gray-level histogram, textures, and NDVI(Normalized Difference Vegetation Index) of target imagery. Moreover, in order to minimize the errors in the classification network, the Gradient Descent method was used in the training process for the $\gamma$-parameters at each code used. The trained parameters made it possible to know the connectivity of each node and to delete the void features from all the possible input features.

• Journal of IKEEE
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• v.26 no.1
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• pp.89-94
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• 2022

The W-band (75-110GHz) is a band that can utilize at least 10 times more bandwidth than the existing 5G band. Therefore, it is one of the bands suitable for future mobile communication that requires high speed and low latency, such as virtual and augmented reality. However, since the wavelength is short, it has a high path loss and is very sensitive to the atmospheric environment. Therefore, in order to develop a W-band communication system in the future, it is necessary to analyze the characteristics of path loss according to the channel environment. In this paper, to analyze the characteristics of the W-band path loss, the random forest technique was used, and the influence of the channel parameters according to the distance section was analyzed through the path loss data according to various channel environment parameters. As a result of the simulation, the distance has the highest influence on the path loss in the short distance, and the other channel environment factor is almost ignored. However, as the distance section became longer, the influence of distance decreased while the impact of clutter and rainfall increased.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.160-166
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• 2014

Because of industrial development, industrial facilities are becoming more complex and diversified. Plant industries are focused on productivity improvement, cost reduction, and product uniformity by simplifying production processes using automated control. Furthermore, plant industries require higher pressures and temperatures to improve energy efficiency. For this reason, the valves used in plants are operated under harsh conditions. Globe valves and gate valves are mainly used for high pressure these days. However, these valves have various problems, including low maintainability and high cost, due to structural problems. Therefore, butterfly and ball valve applications are increasing in industrial plants. This paper suggests a quadruple-offset butterfly valve that is applicable to bi-direction use, and the principle design parameters are suggested. The selected design parameters are an eccentric flange center line and shaft centerline(Offset 1), an eccentric seat centerline and disc shaft centerline(Offset 2), the angle between the flange centerline and seat wedge angle(Offset 3), the angle between the vertical direction of the disc shaft centerline and seat centerline(Offset 4), and the seat engagement angle. To analyze the interaction effect of the design parameters, ANOM and ANOVA were performed with an orthogonal array. The parameters were found to have effects in the following order: Offset 2, Offset 1, engagement angle, Offset 3, and Offset 4. The interaction between the parameters was insignificant.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.242-253
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• 2011

The typical missions for the current stand-off UAVs are surveillance and reconnaissance. On the other hand, the primary mission for the future UCAS will be combat mission such as SEAD under the man-made ultimately hostile environment including SAM, antiaircraft artillery, threat radar, etc. Therefore, one of the most important challenges in UCAS design is improvement of survivability. The current studies for aircraft combat survivability are focused on the improvement of susceptibility and vulnerability of manned aircraft system. Although the survivability design methodology for UCAS might be very similar to the manned combat system but there are some differences in mission environment, system configuration, performance between manned and unmanned systems. So the parameters and their sensitivities which affect aircraft combat survivability are different in qualitatively and quantitatively. The susceptibility related parameters for F-16 C/D and X-45A as an example of manned and unmanned system are identified and the susceptibility parameter sensitivities are analyzed by using Monte-Carlo Simulation in this study.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.145-150
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• 2000

The adaptation for a right source on the retina consists of the light-dark adaptation's two curves for a time by the rod-cone receptor. We obtained the adaptation for a time to measure the threshold intensities, it was two decay curves by the center of a rod-cone break. It could be represented the dark adaptation by a exponential decay function consisting of $T_{min}$, $a_r$, $a_c$, $T_{0(r)}$, $T_{0(c)}$, $t_b$, $t_c$'s parameters. The curves of a $t_b$ below and a $t_b$ above showed the adaptation sensitivity of the cone and the rod. The exponential decay function was well applied to the dark adaptation in difference retinal positions, in contrally fixated fields, in luminous, as age etc. It could be used the decay parameter as the index because of representing the properties of the dark adaptation's function.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.903-914
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• 2008

This study was undertaken for the production capacity expansion and energy saving through entire process simulation and optimization for the commercial process of manufacturing monoethylene glycol as a staple from ethylene oxide. Aspen $Plus^{TM}$(ver. 2006) was employed in the simulation and optimization work. The multicomponent vapor-liquid equilibria involved in the process were calculated using the NRTL-RK equation. As for the binary interaction parameters required for a total of 91 binary systems, those for 8 systems were self-supplied by the simulator, those for 28 systems were estimated through regression of the VLE data in the literature, and the remainder were estimated with the estimation system built in the simulator. Subsequent to ascertaining the accuracy of the generated parameters through comparison between actual and simulated process data, sensitive variables highly affecting the process were searched and selected using sensitivity analysis tool in the simulator. The optimum operating conditions minimizing the total heat duty of the process were investigated using the optimization tool based on the successive quadratic programming in the simulator.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.255-257
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• 2008

초고속 전기정보의 전송 시대와 U-정보전자시대에 응용하는 최신 정보기기와 의료기기 및 군사정보의 실시간 전송을 위하여 많은 실시간 알고리즘과 모델링의 연구가 필수적이다. 또한 원격지에 많은 전기 및 전력정보를 비선형적 특성이 있는 환경하에서도 정보의 오차가 없이 실시간으로 전송하는 기술은 현대 정보사회에서 해결해야 할 매우 중요한 요소중에 하나이다. 이러한 내용으로 수행되어지는 신경회로망을 이용한 실시간 모델링을 제안하고자 한다. 이와 관련한 일반적인 방법으로 역전파 학습 알고리즘을 들 수 있다. 파라미터에도 덜 민감하며, 특히 온라인으로 인식과 제어가 가능하도록 수렴속도를 향상 시켜야하는 새로운 모델의 필요성이 요구된다. 본 연구에서는 기존의 신경회로망이 가지고 있는 여러 단점들을 개선하고자 새로운 학습 알고리즘과 새로운 구조의 신경회로망을 제시한다. 또한 제시한 알고리즘을 이용하여 불규칙적 시스템 모델망과 다양한 센서 모델링 등에 연결하여 다양한 실험을 수행하여 그 결과를 보여 실시간 특성을 갖는 것을 입증해 보였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.181-182
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• 2012

마이크로그리드 계통 연계 운전시 분산 발전은 main grid와 함께 연계되어 부하의 수요를 담당한다. 하지만 계통사고나 의도적인 제어 전략으로 인해 분산 발전은 계통과 분리되어 단독으로 부하의 수요를 담당하게 된다. 이때 분산발전을 기반으로 한 인버터는 계통 연계 운전 시 하나의 전류원으로서의 역할을 하다가 시스템이 단독 운전 모드로 전환시 전압원으로 가정되게 된다. 이러한 특성으로 인해 단독운전 모드시의 인버터 병렬 운전은 시스템 파라미터와 라인 임피던스에 매우 민감해진다. 따라서 본 논문에서는 단독운전 모드시 불평형 저전압 마이크로그리드에서 대두되는 문제들에 대해 분석하고 가상 인덕터와 기준 전압 조정을 활용한 개선된 드룹 방식의 적용을 통해 이를 해결하고자 하였다. 제안된 이론은 PSIM 시뮬레이션을 통해 검증되었다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.152-153
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• 2019

본 논문에서는 캐패시터-분할 타입 능동전력 디커플링 회로를 위한 전압제어 방법을 제안한다. 능동전력 디커플링 회로는 시스템에 필요한 커패시턴스를 낮추어 전해커패시터를 필름 커패시터로 대체하여 시스템 수명과 전력밀도를 높일 수 있는 장점이 있다. 그러나 일반적으로 오픈 루프 제어방식의 전압제어 방식을 사용하여 파라미터 값의 변화에 민감하다는 단점을 가지고 있다. 이에 본 논문에서는 커패시터-분할 타입 능동전력 디커플링 회로를 위한 폐루프 제어 방법을 제안한다.