• Title/Summary/Keyword: Global Minimum Point

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Drowsiness Sensing System by Detecting Eye-blink on Android based Smartphones

  • Vununu, Caleb;Seung, Teak-Young;Moon, Kwang-Seok;Lee, Suk-Hwan;Kwon, Ki-Ryong
    • Journal of Korea Multimedia Society
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    • v.19 no.5
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    • pp.797-807
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    • 2016
  • The discussion in this paper aims to introduce an approach to detect drowsiness with Android based smartphones using the OpenCV platform tools. OpenCV for Android actually provides powerful tools for real-time body's parts tracking. We discuss here about the maximization of the accuracy in real-time eye tracking. Then we try to develop an approach for detecting eye blink by analyzing the structure and color variations of human eyes. Finally, we introduce a time variable to capture drowsiness.

Efficient Adaptive Global Optimization for Constrained Problems (구속조건이 있는 문제의 적응 전역최적화 효율 향상에 대한 연구)

  • Ahn, Joong-Ki;Lee, Ho-Il;Lee, Sung-Mhan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.557-563
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    • 2010
  • This paper addresses the issue of adaptive global optimization using Kriging metamodel known as EGO(Efficient Global Optimization). The algorithm adaptively chooses where to generate subsequent samples based on an explicit trade-off between reduction of global uncertainty and exploration of the region of the interest. A strategy that saves the computational cost by using expectations derived from probabilistic nature of approximate model is proposed. At every iteration, a candidate test point that seems to be feasible/inactive or has little possibility to improve for minimum is identified and excluded from updating approximate models. By doing that the computational cost is saved without loss of accuracy.

4차 고다드 알고리즘의 몇 가지 수렴 성질: 2. 평균성능함수의 기하

  • 최진호;배진수;송익호;박래홍;이민수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.9
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    • pp.2355-2361
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    • 1996
  • Convergence analysis on Godard's quartic(GQ) algorithm used for blind equalization is accomplished in this paper. First, we explain the local behavior of the GQ algoithm around the global minimum point of the average performance function. Then we consider the geometry of the average performance function. The main result is that a good initial parameter vector of the GQ algorithm can be chosen based on the information of the geometry of the average performance function.

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Optimal Control by the Gradient Method (경사법에의한 최적제어)

  • 양흥석;황희융
    • 전기의세계
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    • v.21 no.3
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    • pp.48-52
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    • 1972
  • The application of pontryagin's Maximum Principle to the optimal control eventually leads to the problem of solving the two point boundary value problem. Most of problems have been related to their own special factors, therfore it is very hard to recommend the best method of deriving their optimal solution among various methods, such as iterative Runge Kutta, analog computer, gradient method, finite difference and successive approximation by piece-wise linearization. The gradient method has been applied to the optimal control of two point boundary value problem in the power systems. The most important thing is to set up some objective function of which the initial value is the function of terminal point. The next procedure is to find out any global minimum value from the objective function which is approaching the zero by means of gradient projection. The algorithm required for this approach in the relevant differential equations by use of the Runge Kutta Method for the computation has been established. The usefulness of this approach is also verified by solving some examples in the paper.

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An Improved Mean-Variance Optimization for Nonconvex Economic Dispatch Problems

  • Kim, Min Jeong;Song, Hyoung-Yong;Park, Jong-Bae;Roh, Jae-Hyung;Lee, Sang Un;Son, Sung-Yong
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.80-89
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    • 2013
  • This paper presents an efficient approach for solving economic dispatch (ED) problems with nonconvex cost functions using a 'Mean-Variance Optimization (MVO)' algorithm with Kuhn-Tucker condition and swap process. The aim of the ED problem, one of the most important activities in power system operation and planning, is to determine the optimal combination of power outputs of all generating units so as to meet the required load demand at minimum operating cost while satisfying system equality and inequality constraints. This paper applies Kuhn-Tucker condition and swap process to a MVO algorithm to improve a global minimum searching capability. The proposed MVO is applied to three different nonconvex ED problems with valve-point effects, prohibited operating zones, transmission network losses, and multi-fuels with valve-point effects. Additionally, it is applied to the large-scale power system of Korea. The results are compared with those of the state-of-the-art methods as well.

A STUDY ON THE SIMULATED ANNEALING OF SELF ORGANIZED MAP ALGORITHM FOR KOREAN PHONEME RECOGNITION

  • Kang, Myung-Kwang;Ann, Tae-Ock;Kim, Lee-Hyung;Kim, Soon-Hyob
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06c
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    • pp.407-410
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    • 1994
  • In this paper, we describe the new unsuperivised learning algorithm, SASOM. It can solve the defects of the conventional SOM that the state of network can't converge to the minimum point. The proposed algorithm uses the object function which can evaluate the state of network in learning and adjusts the learning rate flexibly according to the evaluation of the object function. We implement the simulated annealing which is applied to the conventional network using the object function and the learning rate. Finally, the proposed algorithm can make the state of network converged to the global minimum. Using the two-dimensional input vectors with uniform distribution, we graphically compared the ordering ability of SOM with that of SASOM. We carried out the recognitioin on the new algorithm for all Korean phonemes and some continuous speech.

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A homotopy method for solving nonlinear optimization problems (비선형 최적화 문제를 풀기 위한 Homotopy 방법)

  • Han, Gyu-Sik;Lee, Dae-Won;Lee, Jae-Uk
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2004.05a
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    • pp.111-114
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    • 2004
  • 기존의 도함수에 기초한 수치적 최적화 기법들(derivative-based optimization)은 비선형 최적화 문제를 풀기 위해 목적식의 1차 도함수의 정보를 이용하여 정류점(stable point)인 최적해를 찾아 나가는 방식을 취하고 있다. 그러나 이런 방법들은 목적식의 국부 최적해(local minimum)을 찾는 것은 보장하나, 전역 최적해(global minimum)를 찾는 데에는 실패할 경우가 많다. 국부 최적해와 전역 최적해는 모두 목적식의 1차 도함수가 '0'인 값을 가지는 특징이 있으므로, 국부 또는 전역 최적해를 구하는 구하는 과정은 목적식의 1차 도함수가 '0'인 해를 찾는 방정식 문제로 변환될 수 있다. 따라서 본 논문에서는 비선형 방정식의 해를 찾는데 좋은 성능을 보이는 Homotopy 방법을 이용하여 목적식의 1차 도함수에 관한 비선형 방정식을 풀고, 이를 통해 비선형 최적화 문제의 모든 국부 최적해를 찾아냄으로써 전역 최적화 문제를 해결하는 방법을 제안하고자 한다. 제안된 방법론을 다양한 전역 최적화 문제에 적용한 결과, 기존의 방법들에 비해 더 좋은 성능을 보임을 알 수 있었다.

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Ab Initio Study on the Structure and Energetics of (CO)2

  • Park, Young-Choon;Lee, Jae-Shin
    • Bulletin of the Korean Chemical Society
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    • v.26 no.9
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    • pp.1421-1426
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    • 2005
  • The stationary point structures and relative energies between them as well as binding energies of $(CO)_2$ have been investigated at the CCSD(T) level using the correlation-consistent basis sets aug-cc-pVXZ(X=T,Q,5). It is found that while the equilibrium structure corresponds to the C-bonded T-shaped configuration with intermolecular distance of 4.4 $\AA$, there exists another minimum, slightly higher in energy ($\sim$10 $cm^{-1}$) than the global minimum, corresponding to the O-bonded T-shaped configuration with the intermolecular distance of 3.9 $\AA$. The CCSD(T) basis set limit binding energy of $(CO)_2$ is estimated to be 132 $cm^{-1}$.

Control of the Hydraulic System Using the Global Sliding Mode Control (전역슬라이딩모드 제어를 이용한 전기유압 시스템의 제어)

  • 최형식;김명훈
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.2
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    • pp.218-228
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    • 2003
  • A hydraulic system is modeled as the second order differential equation with uncertain system parameters and disturbance composed of modeling errors. To Position the load of the hydraulic system to a desired point. the servo valve of the hydraulic system is controlled. As a control scheme. a global sliding mode control(GSMC) is Proposed Since the servo valve has a torque limit. the GSMC is designed to coordinate the position of the load along the minimum time trajectory within the torque limit. The Proposed control scheme can be designed with ranges of parametric uncertainties and specified torque limits. By the proposed control scheme, the closed form solution of the arriving time at the desired position can be estimated.

Pitch Period Detection Algorithm Using Modified AMDF (변형된 AMDF를 이용한 피치 주기 검출 알고리즘)

  • Seo Hyun-Soo;Bae Sang-Bum;Kim Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.1
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    • pp.23-28
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    • 2006
  • Pitch period that is a important factor in speech signal processing is used in various applications such as speech recognition, speaker identification, speech analysis and synthesis. So many pitch detection algorithms have been studied until now. AMDF which is one of pitch period detection algorithms chooses the time interval from valley point to valley point as pitch period. In selection of valley point to detect pitch period, complexity of the algorithm is increased. So in this paper we proposed the simple algorithm using rotation transform of AMDF that detects global minimum valley point as pitch period of speech signal and compared it with existing methods through simulation.