• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.395-398
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• 1998

In this paper, a method for the improvement of learning speed and convergence rate was proposed applied it to physiological neural structure with the advantages of artificial neural networks and fuzzy theory to physiological neuron structure, To compare the proposed method with conventional the single layer perception algorithm, we applied these algorithms bit parity problem and pattern recognition containing noise. The simulation result indicated that our learning algorithm reduces the possibility of local minima more than the conventional single layer perception does. Furthermore we show that our learning algorithm guarantees the convergence.

• Journal of The Korean Astronomical Society
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• v.46 no.4
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• pp.151-159
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• 2013

We discuss the orbital period changes of the Algol semi-detached eclipsing binary DI Peg by constructing the (O-C) residual diagram via using all the available precise minima times. We conclude that the period variation can be explained by a sine-like variation due to the presence of a third body orbiting the binary, together with a long-term orbital period increase (dP/dt=0.17 sec/century) that can be interpreted to be due to mass transfer from the evolved secondary component (of rate $1.52{\times}10^{-8}M_{\odot}/yr$) to the primary one. The detected low-mass third body ($M_{3min.}=0.22{\pm}0.0006M_{\odot}$) is responsible for a periodic variation of about 55 years light time effect. We have determined the orbital parameters of the third component which show a considerable eccentricity $e_3=0.77{\pm}0.07$ together with a longitude of periastron ${\omega}_3=300^{\circ}{\pm}10^{\circ}$.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1512-1518
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• 2004

Rescaled Simulated Annealing (RSA) has been adapted to solve combinatorial optimization problems in which the available computational resources are limited. Simulated Annealing (SA) is one of the most popular combinatorial optimization algorithms because of its convenience of use and because of the good asymptotic results of convergence to optimal solutions. However, SA is too slow to converge in many problems. RSA was introduced by extending the Metropolis procedure in SA. The extension rescales the state's energy candidate for a transition before applying the Metropolis criterion. The rescaling process accelerates convergence to the optimal solutions by reducing transitions from high energy local minima. In this paper, structural optimization examples using RSA are provided. Truss structures of which design variables are discrete or continuous are optimized with stress and displacement constraints. The optimization results by RSA are compared with the results from classical SA. The comparison shows that the numbers of optimization iterations can be effectively reduced using RSA.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.971-974
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• 1987

Considering heat transfer and heat loss processes for the heat engine operating between two fixed heat reservoirs, it may be qualitatively explained that the maxima of power output and its efficiency depending upon operating conditions are extreme maxima. Furthermore, it is also found that from an economic point of view the above two extremes are related to extreme minima of plant cost per unit power output and operation cost per unit power output respectively, and the condition of minimum cost per unit power output exists between the extreme minimum conditions of plant cost per unit power output and that of operation cost per unit power output.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.1
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• pp.49-54
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• 2006

The purpose of RVSM is to reduce vertical separation minima for aircrafts which operate between FL290- FL410 inclusive in regional airspace, and to increase airspace capacity by providing additional flight levels. In order to introduce RVSM, it is necessary to estimate quantitatively airborne collision risk due to the reduction in vertical separation minimum. In this study, the basic concept of RVSM safety assessment and Reich collision risk model are introduced and mid-air collision risk in Incheon FIR is estimated based on ICAO RVSM safety assessment technique and Reich Model.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.262-266
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• 2001

We have presented the electrical properties of the quantum wire fabricated by split gate on GaAs/AlGaAs heterostructures by using the Shubnikov de Haas oscillation and quantum Hall effect measurements. We observed the 1D properties of the sample as increasing gate voltage. The misfit between quantum Hall plateau and minima in Shubnikov do Haas oscillations are interpreted as Landauer-B$"{u}$ tikker formula based on the edge state transport.port.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.333-336
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• 1991

In this paper, Hopfield & Tank model-like artificial neural network structure is proposed, which can be used for the optimal path planning problems such as the unit commitment problems or the maintenance scheduling problems which have been solved by the dynamic programming method or the branch and bound method. To construct the structure of the neural network, an energy function is defined, of which the global minimum means the optimal path of the problem. To avoid falling into one of the local minima during the optimization process, the simulated annealing method is applied via making the slope of the sigmoid transfer functions steeper gradually while the process progresses. As a result, computer(IBM 386-AT 34MHz) simulations can finish the optimal unit commitment problem with 10 power units and 24 hour periods (1 hour factor) in 5 minites. Furthermore, if the full parallel neural network hardware is contructed, the optimization time will be reduced remarkably.

• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.31-34
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• 2009

ART2 알고리즘은 신경 회로망 모델로서 실시간 학습이 가능하여 저속 및 고속을 지원할 뿐만 아니라 지역 최소화(local minima) 문제가 발생하지 않는 장점을 갖는다. 그러나 ART2 알고리즘은 경계 변수 설정에 따라 클러스터의 수가 달라지며, 이러한 경계 변수 설정은 패턴의 분류와 인식 성능을 좌우한다. 따라서 본 논문에서는 ART2 알고리즘에서 효율적으로 경계 변수를 설정하기 위해 패턴셋 설정을 통한 경계 변수 설정 방법을 제안한다. 제안된 경계 변수 설정 방법의 성능을 평가하기 위해 숫자 및 영문 패턴을 대상으로 실험한 결과, 패턴 분류의 성능이 기존의 방식 보다 개선된 것을 확인하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.210-216
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• 2010

In this study, we propose a novel method to segment an individual tooth region in a true color image. The difference of the intensity in RGB is initially extracted and subsequent morphological reconstruction is applied to minimize the spurious segmentation regions. Multiple seeds in the tooth regions are chosen by searching regional minima and a Sobel-mask edge operations is performed to apply MCWA(Marker-Controlled Watershed Algorithm). As the results of applying MCWA transform for our proposed tooth segmentation algorithm, the individual tooth region can be resolved in a CCD tooth color image.

• Journal of Astronomy and Space Sciences
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• v.8 no.1
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• pp.73-83
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• 1991

UBV light curves of an early type close binary AQ Cas are made with the observations obtained at Yonsei University from 1982 to 1989. Light losses in U are shown at the phase around 0.55 and 0.90 which might be produced by the stream of mass transfer. Four times of minimum light derived from our observations. With the collected minima including ours, new light elements are determined. Phtometric solution with B and V light curves is made by using Wilson-Devinney codes.