• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1C
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• pp.110-116
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• 2008

Maximum likelihood(ML) diretion-of-arrival(DOA) estimation is essentially optimization of multivariable nonlinear cost function. Since the final estimate is highly dependent on the initial estimate, an initialization is critical in nonlinear optimization. We propose a multi-dimensional(M-D) search scheme of uniform exhaustive search and improved exhaustive search. Improved exhaustive search is superior to uniform exhaustive search in terms of the computational complexity and the accuracy of the estimates.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.17-26
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• 2008

This paper has for its object to propose AFOD(Adaptive First-Order Decimator) which sets a value of decimated element as an average of a value of neighbor intelligible component and a output value of FOD(First-Order Decimator) for the target pixel, and to analyze its performance in terms of subjective image quality and hardware complexity. In the proposed AFOD, a target pixel located at the center of sliding window is selected first, then the gradient amplitudes of its right neighbor pixel and its lower neighbor pixel are calculated using first order derivative operator respectively. Secondly, each gradient amplitude is divided by the summation result of two gradient amplitudes to generate each local intelligible weight. Next, a value of neighbor intelligible component is defined by adding a value of the right neighbor pixel times its local intelligible weight to a value of the lower neighbor pixel times its intelligible weight. Since the proposed method adaptively reflects neighbor intelligible informations of neighbor pixels on the decimated element according to each local intelligible weight, it can effectively suppress the blurring effect being the demerit of FOD. It also possesses the advantages that it can keep the merits of FOD with the good results on average but also lower computational cost.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.3-9
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• 2015

In this paper, we propose the operation procedures of the 1-channel monopulse receiver which achieves the new configuration. Also, we analyzed the monopulse ratio and the target angle accuracy of the fabricated receiver by using the monopulse signal generator developed for verifying the proposal equipment. As a result, it is apparent that the monopulse ratio of the proposal receiver is equal to that of the 3-channel monopulse receiver. Also, the fabricated receiver exhibits the target angle accuracy with fewer than 0.1 RMS. The proposal receiver achieves the simple receiver configuration and the simple tracking procedures, as contrasted with the 3-channel monopulse receiver. Also, the proposal receiver has advantages in terms of size, weight, cost and power. Because the proposal monopulse receiver requires 1-channel receiver and needs not the signal processor in comparison with 3-channel monopulse receiver which requires 3-channel receiver and need the signal processor.

• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.915-961
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• 2010

This study is concerned with health damages from $SO_2$ under different assumptions on the relationship between air concentrations and their marginal health impacts. $SO_2$ concentration profiles resulting under emission caps, and a system of tradable emission allowances are compared. Using slopes and curvatures of the health response function consistent with evidence in medical literature, emission caps are shown to lead to lower aggregate damages under all considered parameters, an advantage of $26~452 million. The benefit of emission caps over tradable allowances increases with the curvature of the response function, but falls with its slope. The advantage of emission caps in terms of environmental damages is never overturned completely for the considered functional forms. The marginal damage function would have to be steeper than what the current medical evidence suggests for price instruments to outperform emission caps in terms of aggregate damages. With other welfare consequences included-emission abatement costs, consumer and producer surpluses, and government revenue-emission caps always lead to a $3.7~4.1 billion greater measure of social welfare.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1393-1402
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• 1999

This paper proposes an efficient principal feature extraction of the image data using neural networks of a new learning algorithm. The proposed learning algorithm is a backpropagation(BP) algorithm based on the steepest descent and dynamic tunneling. The BP algorithm based on the steepest descent is applied for high-speed optimization, and the BP algorithm based on the dynamic tunneling is also applied for global optimization. Converging to the local minimum by the BP algorithm of steepest descent, the new initial weights for escaping the local minimum is estimated by the BP algorithm of dynamic tunneling. The proposed algorithm has been applied to the 3 image data of 12${\times}$12pixels and the Lenna image of 128${\times}$128 pixels respectively. The simulation results shows that the proposed algorithm has better performances of the convergence and the feature extraction, in comparison with those using the Sanger method and the Foldiak method for single-layer neural networks and the BP algorithm for multilayer neural network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1925-1931
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• 2011

This paper suggests an approach to the subtle concept, "good", through the fuzzy logic and the design of the Canny edge detector of Gray scale images based on the rules of fuzzy anisotropic diffusion. The Canny edge detection algorithms design is to divide the gray levels into pixels and then calculate the diffusion coefficients at each pixel of non-edgy regions. Based on this processing, we present the Canny edge detector implementing fuzzy logic and comparing the results to other existing methods. The proposed approach is the narrow dynamic range of the gray-level image Sharpening the edge detection and has the advantage.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.321-326
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• 2004

Many researchers have been studied texturing the 3D face model with front and side pictures of ordinary person. It is very important to exactly detect the psition of eyes, nose, mouth of a human from the side pictures. Previous results first found the position of eye, nose, or mouth and then extract the other face components using their positional correlation. The detection results greatly depend on the correct extraction of the neck from the images. Therefore, we present a new algorithm that remove the neck completely and thus improve the detection rates of face components. To do this, we will use the RGB values and its differences.

• Korean Journal of Materials Research
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• v.6 no.3
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• pp.253-263
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• 1996

고온.고압하에서 장시간 사용되는 고온부재용 구조물은 경년열화현상을 나타낸다 그러므로 구조물의 안정성 측면에서 재질열화의 정도를 정량적으로 평가하는 것이 중요하다. 그러나 실기 구조물에서 채취할 시험편의 크기와 수는 제한이 되기 때문에 새로운 비파괴적인 평가법이 요구되고 있다. 따라서 본 연구에서는 화력발전설비에 이용되는 탄소강과 페라이트강에 대한 열화도의 평가를 위해 입계부식법의 적용 가능성을 조사한다. 시험결과, 재질열화의 정도는 사용시간보다 사용온도에 더 큰 영향을 받았으며, Larson-Miller인자와 열화도([$\Delta$DBTT]SP)사이의 관계는 선형적이었으나, 강종에 따라 다른 기울기를 보였다. 반면, 연성-취성천이온도 ([$\Delta$DBTT]SP)와 격자절단비(Ni/No)와 관계는 강종에 무관하게 선형적인 비례관계를 나타내었다. 또한, [$\Delta$DBTT]SP와 Ni/No 의 관계로부터 입계부식법은 페라이트계 강뿐만아니라 탄소강에 대해서도 유용한 재질열화 평가 방법임을 알 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.591-594
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• 2003

본 논문은 중심 화소의 FOD 성분값과 인접 가해 성분값의 평균으로 축소 성분값을 산출함으로써 FOD에 적응성을 부여한 디지털 영상 축소 알고리즘의 성능을 분석함에 그 목적이 있다. 제안된 방법은, 중심 화소의 우측 및 하측 인접 화소의 기울기의 크기를 이용하여 산출한 각각의 국부 가해 가중치를 우측 및 하측 인접 화소값에 곱한 후에 그 결과를 합산함으로써 인접 가해 성분값을 구하고 FOD 성분값과 이 인접 가해 성분값을 평균하여 축소 성분값을 구하는 과정을 전체 영역에 반복적으로 수행함으로써 축소 영상을 얻을 수 있다. 제안된 축소 방법에 따르면, 적은 연산량을 요하면서도 평균적으로 우수한 결과를 제공하는 FOD 방식의 장점을 취하면서 인접 화소의 유효 가해 성분을 각각의 국부 가해 가중치에 따라 축소 성분값에 적응적으로 반영함으로써 FOD의 단점인 몽롱화 현상을 효과적으로 억제시킬 수 있는 바, 개선된 정보 보존성을 제공할 수 있는 이점이 있다. 본고에서는 주관적인 성능과 하드웨어 복잡도 측면에서 제안된 방법과 기존의 각 방식에 대한 성능을 분석 평가한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.82-85
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• 2006

A trapezoidal fin with various lateral surface slopes is designed optimally by using one-dimensional analytic method. For four different convection characteristic numbers, the trend of heat loss as a function of fin tip length is shown. The optimum heat loss is somewhat arbitrarily chosen as 92% of the maximum heat loss. The optimum fin length corresponding to this optimum heat loss versus convection characteristic number is presented. The optimum effectiveness and specific effectiveness is presented as a function fin shape factor.