• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.7
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• pp.907-912
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• 1993

In this Paper we have proposed a new method to implement the interpolation of the functions, using a neural network. The architecture of neural network is a three-layer perceptron and the training algorithm is a modified error back propagation algorithm adding neurons to hidden layer. The interpolated functions are sin(7 X), 3rd order polynomial 0.5$\times$3_2$\times$2+X+2.5 and rectangular pulse 0.99 U (X-0.2) -0.99 U(X-0.8) +0.01, where U(X) is the unit step. The root mean squred errors of the interpolated functions are 0.00258, 0.00164 and 0.00116 respectively.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.167-174
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• 2010

Recently the distributed topology control algorithm for constructing the Recrystallization Topology in the unstructured peer-to-peer network was proposed. In this paper, we prove that such a hierarchical topology is a scale-free power-law network. We present a model of a construction process of the distributed protocol, and analyze it based on a mean-field approximation and the continuum theory, so that we show that the constructed Recrystallization Topology is a scale-free network. In the proposed model, all nodes are born with some initial attractiveness and the system incorporates the rewiring of some links at every time step. Some old links are removed with the anti-preferential probability, and some new links are added with preferential probability. In other words, according to the distributed algorithm, each node makes connections to the more-preferential nodes having higher hit-ratio than other nodes, while it disconnects the anti-preferential nodes having lesser hit-ratio. This gives a realistic description of the local processes forming the recrystallization topology in unstructured peer-to-peer network. We calculate analytically the degree distribution. The analytic result indicates that the constructed network is a scale-free network, of which the scaling exponent is 3.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.77-86
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• 2004

In general, small-sized neural networks, even though they show good generalization performance, tend to fail to team the training data within a given error bound, whereas large-sized ones learn the training data easily but yield poor generalization. Therefore, a way of achieving good generalization is to find the smallest network that can learn the data, called the optimal-sized neural network. This paper proposes a new scheme for network pruning with ‘impact factor’ which is defined as a multiplication of the variance of a neuron output and the square of its outgoing weight. Simulation results of function approximation problems show that the proposed method is effective in regression.

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.19-25
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• 2011

This paper presented neural network modeling method using vehicle data to predict fuel consumption. To acquire data for training and testing the proposed neural network, medium-class gasoline vehicle drove at downtown and parameters measured include speed, engine rpm, throttle position sensor (TPS), and mass air flow (MAF) as input data, and fuel consumption as target data from OBD-II port. Multi layer perception network was used for nonlinear mapping between the input and the output data. It was observed that the neural network model can predict the vehicle quite well with mean squared error was $1.306{\times}10^{-6}$ for the fuel consumption.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.256-262
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• 1998

The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit, and it is difficult to control the desired torque. This paper proposes inductance modeling method using ANN(Artificial Neural Network) that is used to simulate the inductance which is nonlinearly varied with rotor position and current. The torque ripple is analyzed and input voltage and current condition to reduce torque ripple is simulated by inductance model.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.44-45
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• 2000

Shack-Hartmann 센서로부터 얻어진 기울기 정보로부터 파면을 재구성하고 분석하기 위해서는 각각의 점 영상에 대한 위상 구배로부터 파면의 위상을 재구성할 수 있는 수학적인 알고리즘이 필요하다. 파면의 위상을 재구성하기 위한 알고리즘은 Hudgin, Fried, Southwell이 제시한 세 가지 방법에 대한 연구결과가 가장 많이 알려져 있다. 본 연구에서는 CCD 카메라로부터 전송된 디지털 영상에서 각각의 점 영상의 중심점을 추출하여 점 영상의 이동정보로부터 수평과 수직방향의 기울기를 계산하고, 이를 바탕으로 최소제곱법(least-square fitting)을 사용하여 위상을 재구성하였다. 파면의 기울기 정보로부터 파면을 재구성하기 위해 기존의 이론을 바탕으로 행렬계산법을 사용하여 각각의 경우를 일반화하였고, 위상의 복구와 파면의 보정에 따른 해석적인 오차의 관계를 논의하였다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.190-191
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• 2000

종래의 자기광학 디바이스는 자성체막을 빛이 투과할 때 얻어지는 페러데이 회전각을 이용했기 때문에, 페러데이 회전각을 증가시켜서, 광학적 성능을 증가시키려면 자성체막의 두께를 증가시켜야만 했다. 그러나, 자성체막의 두께를 증가시키면, 화소를 자기적으로 분리하기 위하여 자성체 막을 물리적으로 제거 해야하여 깊이가 깊어지고 그 후에 도선막을 구조화하기 위하여 파낸 화소간 갭을 다시 평탄화해야 하는 등의 제조 공정이 기술적으로 매우 어려워진다는 문제점을 가지고 있었다. 또한, 자성체 막의 두께가 증가하면, 도선막에 전류를 흘려 발생하는 자장은 도선막으로부터의 거리의 제곱에 반비례하므로, 두꺼운 자성체 막 전체에 강한 자장을 인가하기 위해서는, 도선막에 흘리는 전류를 증가시켜야만 한다는 문제점을 안고 있었다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.40-41
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• 2000

광학설계의 최적화에서는 최소자승법과 감쇠최소자승법이 주로 사용되고 있다. 최소자승법은 error의 제곱의 합을 최소화하는 방법으로, 이 방법은 최적점 부근에서의 불안정성이 발생하는 문제점이 있다. 감쇠최소자자승법은 최소자승법에 적절한 감쇠항을 부가함으로써 최적점 부근에서의 불안정성을 줄여주고 있다. 본 연구에서는 광학설계의 제한조건을 Lagrange 부정승수$^{(1)}$ 를 사용하여 감쇠최소자승법의 정규방정식에 결합하여 제한조건을 유지하면서 merit function을 줄이는 방법에 대하여 연구하였다. 이 방법에서는 제한조건이 merit function의 error 함수보다 우선적으로 보정되며, 이를 이용하여 매 iteration 마다 merit function에서 절대값이 큰 error를 감쇠최소자승법의 정규방정식에서 제거하고 이 보정조건을 제한조건에 추가함으로서 다른 error항 보다 우선적으로 보정되도록 하였다. 이 때 이 error를 한번에 보정하는 경우에는 merit function의 진동이 심하고 광학계가 사용불가능한 형태로 변화하는 경우가 많아 적절한 target ratio를 설정하여 반복과정을 통하여 점진적으로 보정되도록 하였으며, 이를 통하여 최적화의 안정성을 개선할 수 있었다. (중략)

• Korean Journal of Legislative Studies
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• v.24 no.1
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• pp.241-276
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• 2018

This article measures equal weighted voting to evaluate the fairness of a redistricting system operated in the $4^{th}$ to the $6^{th}$ metropolitan council elections using a new index. The cosine square index using in the article would be useful on what we see the ratio of the equality of population among metropolitan regions and the fairness of the whole electoral system, along with its simple calculation. The results of the fairness of the $4^{th}$ to the $6^{th}$ metropolitan council elections calculated by the cosine square index are as follow: Because the $4^{th}$ metropolitan council election uniformly elects two members for each electoral district regardless of the size of the population, it has a low equality of population between districts. But as a result of the decision of the Constitutional Court in 2007, standard of population variation in electoral district has been strengthened to 4 : 1 from the $5^{th}$ metropolitan council election. It increases significantly equality of population between districts from the $5^{th}$ metropolitan council election. But in the elections from the $4^{th}$ to the $6^{th}$ metropolitan council elections, Rural electoral districts continuously show the lowest equality of population between districts. It also shows the growing disparity between urban and rural areas as well as between capital and non-capital. This paper emphasizes that electoral apportionment in local council elections should reflect regional diversity and community identity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1358-1363
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• 2012

This paper deals with the analysis of high efficiency small antenna like superconductor antenna. The superconductor antenna is useful to low frequency range because surface resistance of superconductor increased with the rate of square of frequency. Thus, the used antenna increases in size. For such a reason, the role of the matching circuit is very important in small antenna. In this paper, low loss antenna included the optimal structure of matching circuit is analyzed by using quasi-static approximation. To verify the results of this paper, input impedance and radiation characteristics of this antenna have been evaluated.