• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.7-13
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• 1999

This paper propose a fuzzy regression method using fuzzy neural networks when a membership value is attached to each input -output pair. First, an architecture of fuzzy neural networks with fuzzy weights and fuzzy biases is shown. Next, a cost function is defined using the fuzzy output from the fuzzy neural network and the corresponding target output with a membership value. A learning algorithm is derived from the cost function. The derived learning algorithm trains the fuzzy neural network so that the level set of the fuzzy output includes the target output. Last, the proposed method is applied to the quality evaluation problem of injection molding

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.202-205
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• 2002

본 논문은 계속적인 소자의 이용은 전기적인 스트레스까지 야기시키는데, 특히 게이트에 인가되는 전압이나 전류 스트레스는 게이트 산화 막의 열화를 야기 시킬 수 있다. 유리기판위에 저온(${\leq}600^{\circ}C$)공정의 고상결정화을 통하여 다결정 박막 트랜지스터를 제작한 후, 이 소자에 게이트와 드레인에 전압 스트레스를 인가하여 출력 특상과 전달특성을 분석하였는데, 그 결과 다결정 실리콘 박막 트랜지스터의 전달특성은 게이트 와 드레인 전압에 의존하는데 임계전압은 긴 채널길이와 좁은 채널 폭에서 높고 출력특성은 갑자기 높은 드레인 전류가 흐른다. 전기적 스트레스가 인가된 소자는 드레인 전류를 감소시킨다. 결국 전계효과 이동도는 긴 채널길이와 좁은 폭의 채널에서 더 빠른 것을 알 수 있다.

• Nuclear Engineering and Technology
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• v.15 no.2
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• pp.135-141
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• 1983

Computational accuracy of the modified Borresen's coarse-mesh diffusion theory scheme is investigated with the steady-state solutions of the two- and three-dimensional LRA-BWR bench-mark problem. By comparing the numerical results available for the critical eigenvalue and power distribution of the LRA-BWR, it is shown that the modified scheme is capable of predicting the power distribution of the multi-dimensional BWR problem with an improved accuracy.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.38-43
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• 1997

이 논문의 목적은 신경망 이론에 의한 노심특성평가 모델과 유전자 기법을 써서 가압경수로 노심의 최적화 재장전 모형을 결정하는데 있다. 이를 위해 OLL(Optimization Layer by Layer)신경망을 구축하고 이를 영광 3호기 재장전주기 노심특성(특히 연료집합체 출력분포와 임계붕산농도)을 예측할 수 있도록 훈련하여 영광3호기 재장전주기 특성 해석용 OLL 신경망을 만들었다. 그리고 통상의 유전자 기법을 활용하여 매세대당 150개의 장전모형들을 생산하고 이들을 대상으로 1000세대에 걸친 유전자 기법에 의한 최적화 과정을 통해 영광 3호기 노심의 평형주기 최적 모형을 결정하였다.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.126-128
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• 1999

평균 빙산 질의란 대용량의 데이터들에 의해 avg 집단 함수를 수행한 뒤 임계값 이상인 데이터들을 결과로 출력하는 연산을 의미한다. 이 때 데이터 도메인의 크기가 메모리에 생성할 수 있는 카운터의 수보다 크기 때문에 연산 처리가 어렵다. 지난 연구에서 빙산 질의에 대해 제안한 해시 카운터는 avg 연사의 경우 착오누락이 발생한다는 문제점이 존재한다. 그래서 이런 문제점들을 해결하며 효율적으로 연산을 수행하기 위해, 데이터베이스를 분할하며 카운터를 관리하는 '메모리 Full 분할', '후보 Full 분할'의 두 알고리즘을 제안한다. 실험결과 두 알고리즘은 메모리크기, 데이터 분포, 데이터 순서에 영향을 받았는데, 데이터들이 정렬이 되어 있거나 데이터분포가 정규분포를 이룰 때 우수한 성능을 보였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.2
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• pp.141-154
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• 2015

In general, conventional criticality analysis for spent fuel transport/storage systems have been performed based on the assumption of fresh fuel concerning the potential uncertainties from number density calculations of actinide nuclides and fission products in spent fuel. However, these evaluation methods cause financial losses due to an excessive criticality margin. In order to overcome this disadvantage, many studies have recently been conducted to design and commercialize a transportation and storage cask applied to the Burnup Credit (BUC). This study conducted an assessment to ensure criticality safety for reactor operating parameters, axial burn-up profiles and misload accident conditions, which are the factors that are likely to affect criticality safety when the BUC is applied to the dual-purpose cask under development at the KOrea RADioactive waste agency (KORAD). As a result, it was found that criticality resulting from specific power, changed substantially and relied on conditions of low enrichment and high burn-up. Considering the end effect in the case of high burn-up produced a positive-definite result. In particular, the increment of maximum effective multiplication factors due to misloading was 0.18467, confirming that misload is a factor that must be taken into account when applying the BUC. The results of this study may therefore be utilized as references in developing technologies to apply the BUC to domestic models and operational procedures or preventing any misload accidents during the process of spent fuel loading.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.791-796
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• 2012

A RF limiter is a component to protect the receiver front end from undesired signal. A RF limiter is a key component whose output is constant level for all inputs above a critical value. A RF limiter use a diode to pass signals of low power while attenuating those above some threshold. A RF limiter for receiver protection in modern radar systems is playing a vital role in order to meet challenges of new interference threats and complicated electromagnetic environments. This paper proposed a new circuit for high power RF limiter whose structure is the combination of the PIN diode and Limit diode. PIN diode take a use of its isolation characteristics which act as a switch does. A 2 kW RF limiter with 200 us pulse width at S-band was developed. It shows good agreements between estimated value and measured results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.34-43
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• 2008

The state-space average model is extended to buck-boost, and buck-boost topology switching mode DC/DC converters and modified to have higher precision without increment of computation. The modified model is used in continuous conduction mode(CCM) switching DC/DC converters and some significant conclusions are derived. This paper discusses the discontinuous conduction mode(DCM) modeling of DC/DC converter and critical characteristic using average model of switch. Average model of switch approach is expended to the modeling of boundary conduction mode DC/DC converters that operate at the boundary between continuous conduction mode(CCM) and discontinuous conduction mode(DCM). Frequency responses predicted by the average model of switch are verified by simulation and experiment. A prototype featuring 15[V] input voltage, 24[V] output voltage, and 24[W] output power using MOSFET.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.5
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• pp.609-615
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• 2020

In the modern society, the use of digital equipment is increasing along with the 4th industrial revolution, and the importance of image and signal processing is increasing. At the same time, research on noise reduction is being actively conducted. In this paper, we propose a switching filter algorithm for random-valued impulse noise cancellation. The proposed algorithm obtains the threshold value by determining the noise level present in the image, and threshold value is compared with the difference between the input pixel value and the reference value, and is used in the weight switching process of the filter. The final output of the filter is estimated by applying a pixel weight and a modified weight median filter according to the switching, and obtains a final output by comparing the estimated value with the input pixel value. To evaluate the performance of the proposed algorithm, we compared it with the existing methods using simulation and PSNR.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.507-522
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• 2021

Specific survey objectives often cannot be met using only one geophysical method, as each method's results are influenced by the specific physical properties of subsurface materials. In particular, areas susceptible to geological hazards require investigation using more than one method in order to reduce risks to life and property. Instead of analyzing the results from each method separately, this work develops a four-quadrant criterion for classifying areas of levees as safe or weak. The assessment is based on statistically determined thresholds of seismic velocity (P-wave velocity from seismic refraction and S-wave velocity from multichannel analysis of surface waves) and electrical resistivity. Thresholds are determined by subtracting the standard deviation from the mean during performance testing of this correlation technique applied to model data of four horizontal and inclined fracture zones. Compared with results from the crossplot of resistivity and P-wave velocity, crossplot analysis using resistivity and S-wave velocity data provides more reliable information on the soil type, ground stiffness, and lithological characteristics of the levee system. A loose and sandy zone (represented by low S-wave velocity and high resistivity) falling within the second quadrant is interpreted to be a weak zone. This interpretation is well supported by the N values from standard penetrating test for the central core.