• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.148.2-148.2
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• 2014

PLS-ll 빔 저장 시 photon absorber에서 튀어나온 광전자는 아래에 위치한 이온펌프의 전극에 흡수되어 컨트롤러에 허위전류를 인가해 부하를 준다. 전극을 향하는 광전자를 차단하기 위해 펌프 입구에 스테인리스 스틸 망을 장착한다. 장착 전 후의 이온펌프 전류 변화를 통해 전자의 차단 유무를 확인하고 펌프의 배기속도 변화를 측정해 이를 여러 가지 계산결과와 비교한다. 컨덕턴스 저하로 인한 실효 배기속도의 감소는 1% 이하로 예상되므로 장착된 스테인리스 스틸 망이 전체 조합펌프의 배기속도에는 큰 영향을 주지 않으며 안정적인 이온펌프 제어를 하게 할 것으로 기대한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1358-1360
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• 2015

본 논문에서는 MB-LBP(Multi-scale Block Local Binary Patterns)와 공간피라미드를 이용하여 생성된 특징을 랜덤 포레스트(Random Forest) 분류기에 적용하여 영상내의 표지판 속도를 인식하는 알고리즘을 제안한다. 입력 영상에서 표지판 영역은 다양한 위치와 크기를 가지며 주위 배경이 후보 영역에 포함되므로 먼저 입력 영상에 원형 Hough Transform을 적용하여 원형의 표지판 후보 영역만을 검출한다. 그 후 영상의 화질을 향상시키기 위해 히스토그램 평활화와 모폴로지 연산을 적용하여 표지판의 숫자 영역과 배경 영역의 대비를 높이도록 한다. 표지판의 크기 변화에 강건한 시스템의 구현을 위해 후보 영역에서 LBP(Local Binary Patterns)보다 우수한 성능을 보이는 MB-LBP를 적용하고, 다양한 크기의 속도 표지판을 인식하기 위해 공간 피라미드를 사용하여 지역적 특징과 전역적 특징 모두를 추출하였다. 추출된 특징은 랜덤 포레스트(Random Forest)를 이용하여 각 9개의 속도 표지판으로 분류, 각 속도별 클래스에 대한 인식 성능을 측정하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1531-1540
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• 1997

In this paper, we presents automatic Korean continuous speech recognizer which is improved by the speech rate estimation and the compensation methods. Automatic continuous speech recognition is significantly more difficult than isolated word recognition because of coarticulatory effects and variations in speech rate. In order to recognize continuous speech, modeling methods of coarticulatory effects and variations in speech rate are needed. In this paper, the speech rate is measured by change of format, and the compensation is peformed by extracting relatively many feature vectors in fast speech. Coarticulatory effects are modeled by defining 514 Korean diphone set, and ETRI's 445 word DB is used for training speech material. With combining above methods, we implement automatic Korean continuous speech recognizer, which shows improved recognition rate, based on DHMM(Discrete Hidden Markov Model).

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.57-63
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• 2010

The damping parameter of Levenberg-Marquardt algorithm switches between error backpropagation and Gauss-Newton learning and affects learning speed. Fixing the damping parameter induces some oscillation of error and decreases learning speed. Therefore, we propose the way of a variable damping parameter with referring to the alternation of error. The proposed method makes the damping parameter increase if error rate is large and makes it decrease if error rate is small. This method so plays the role of momentum that it can improve learning speed. We tested both iris recognition and wine recognition for this paper. We found out that this method improved learning speed in 67% cases on iris recognition and in 78% cases on wine recognition. It was also showed that the oscillation of error by the proposed way was less than those of other algorithms.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.1-6
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• 2008

In this paper, we present the robust fuzzy algorithm for variable speed control of wind turbines. Generally, the plants of wind turbines are consisted of complex nonlinearities, and the parameters of variable speed of wind turbines are represented as uncertain terms. For solving these complexity, we propose the robust fuzzy algorithm. At first, the exact fuzzy modeling are performed for variable speed of wind turbines. Next, we design the fuzzy controller for reanalyzed T-S fuzzy model of the wind turbines, then, we prove the stability of the plant through the Lyapunov stability theorem. At last, an example is included for visualizing the efficiency of the proposed technique.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.84-84
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• 2019

본 연구에서는 홍수터 식생 밀도 변화에 의한 하안침식 관계를 정량적으로 분석하고, 사주의 거동과 사행하천의 발달 관계를 실내실험을 통하여 정량적으로 분석하였다. 이를 정량적으로 파악하기 위하여 수치모형을 적용하여 그 특성을 분석하였다. 시간이 증가함에 따라, 사주의 이동속도는 감소하였다. 하폭이 증가하면서 수심과 소류력이 감소하고, 사행도가 감소하였기 때문이다. 식생의 밀도가 증감함에 따라, 사주의 이동속도가 감소하였다. 식생의 밀도가 증가함에 따라 하안침 식량은 감소하였다. 식생의 밀도가 상대적으로 낮은 곳에서는 저수로가 일정한 형상을 유지하면서 횡방향과 하류로 이동하였다. 시간이 증가함에 따라 저수로의 사행도가 증가하고 있으나, 식생의 밀도가 상대적으로 높은 하도에서는 저수로 사행도가 거의 변화가 없다. 식생밀도가 낮은 곳에서 무차원 곡률반경이 가장 크고, 하안침식속도가 가장 빠르다. 식생밀도가 가장 높은 곳에서는 무차원 곡률반경이 가장 작고, 하안침식속도가 가장 낮았다. 하도 식생은 저수로를 분할시켜서 새로운 저수로가 형성된다. 식생하천에서 하천의 이동, 분할, 저수로 사행도를 변화시키는데 중요한 역할을 한다. 또한 식생의 영향을 고려하여 자유사행의 발달과정을 수치모의 결과, 사행의 발달과정을 잘 모의하였으며, 식생의 밀도가 높은 곳에서 사주의 이동속도는 빠른 특성을 보여주었다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.138-149
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• 2016

The study reviewed the effects of the variable speed limit under adverse weather conditions by using a driving simulator. The study assumed that the display of the reduced speed limit without any change of the weather condition and the display of the same speed limit under the change of the weather conditions violate the expectancy of drivers, so it brings the negative effects on the safety. The study regards drivers conformance as the index of the degree of the compliance of driver expectancy, and utilizes the cumulative probability density within the certain range of the speed including displayed speed limit as the quantitative measure of effectiveness. The study reviewed this assumptions by using a driving simulator. As the results, the cases assumed to violate the expectancy of drivers showed the negative effects on the driving behaviour of driver relatively.

• Elastomers and Composites
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• v.49 no.1
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• pp.73-81
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• 2014

Friction and wear behaviors of natural rubber(NR) compounds were investigated using a blade-type abrader. The effects of temperature, normal load, and rotation speed on wear rate were studied, and wear behaviors of deteriorated compounds were also evaluated. As the rotation speed of specimen and the normal load to specimen increased, the wear rate increased. However, as the experimental temperature increased, the frictional coefficient decreased and the wear rate decreased accordingly. It was found from the wear studies that a power-law relation works between the frictional work input and the wear rate. It was observed that the wear rate dramatically increased by the degradation of the rubber specimen. The wear pattern was developed and the bigger ridge space of the pattern was observed usually in the higher normal load applied. In determining the wear rate of rubber compound, the continuous measurements of wear distance using the blade-type abrader could be successfully used instead of intermittent measurements of wear-loss weight.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.903-909
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• 2018

In this paper, performance analysis of machine vision techniques is presented to improve the convenience and speed of automatic inspection in the industrial field when machine vision is applied to the image not taken in the stationary state, but in the moving state on a conveyer. When the length of cylindrical rods used for automobiles was measured using the edge detection method, the conveying speed increased, and the uncertainty of the boundary between the background and the part image increased, which resulted in a shorter image of the object taken. This paper proposes a linear compensation method to predict the biased errors of the length measurements after examining the pattern of biased and random errors, respectively, with 6 different types of specimens and 7 velocity stages. The length measurement corrected by the linear compensation method had the same accuracy as the stationary state within the speed range of 30 cm/s and could enhance the application capability in automatic inspections.