• ETRI Journal
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• 제14권3호
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• pp.67-74
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• 1992

Discrete variable을 갖는 Mean Field Theory(MFT) neural network은 이미 많은 combinatorial optimization 문제에 적용되어져 왔다. 본 논문에서는 이를 확장하여 continuous variable을 갖는 mean field annealing을 제안하고, 이러한 network에서 integral로 표현되는 spin average를 mean field에 기초하여 어렵지 않게 구할 수 있는 one-variable stochastic simulated annealing을 제안하였다. 이런 방법으로 multi-body problem을 single-body problem으로 바꿀 수 있었다. 또한 이 방법을 이용한 응용으로서 통계학에서 잘 알려진 문제중의 하나인 quantification analysis 문제에 적용하여 타당성을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2590-2592
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• 2000

본 논문에서는 TV 브라운관 유리용해로의 온도 제어를 위한 고전 고급 제어 (Conventional Advanced Control) 알고리듬을 제시한다. 용해로의 특성에 맞도록 중요한 입출력 변수를 선정한 후, 공정 실험을 통하여 얻어진 데이터를 바탕으로 입출력 변수들간의 초보적인 FOPDT (First Order Plus Dead Time) 모델들의 조합으로 용해로를 모델링하였다. 수립된 모델을 바탕으로 주요 입출력을 PI (Proportional - Integral) 형태의 cascade 및 단일 궤환 루프(Single feedback loop)들의 조합으로 제어기를 구성하였다. 제시된 알고리듬은 기존 용해로에 설치되어 있는 DCS를 이용하여 구현되었고, 일 150톤 생산 규모의 용해로에 성공적으로 실적용되었다.

• 대한수학회논문집
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• 제16권3호
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• pp.487-508
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• 2001

We consider the Cauchy problem for Laplacian. Using the single layer representation, we obtain an equivalent system of boundary integral equations. We show the singular values of the ill-posed Cauchy operator decay exponentially, which means that a small error is exponentially amplified in the solution of the Cauchy problem. We show the decaying rate is dependent on the geometry of he domain, which provides the information on the choice of numerically meaningful modes. We suggest a pseudo-inverse regularization method based on singular value decomposition and present various numerical simulations.

• Journal of electromagnetic engineering and science
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• 제5권3호
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• pp.105-111
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• 2005

This paper presents the basic characteristics of a cutoff cavity-backed aperture antenna with a feed post and a parasitic post inserted parallel to the aperture. It is shown that this type of antenna forcibly resonates the cutoff cavity by adding a single external reactance to the parasitic post. The Galerkin's method of moments is used to analyze integral equations for the unknown electric current on each post and the aperture electric field on the aperture. The value of an external reactance for forced resonance is analytically obtained by deriving a determining equation. Also the current distribution on each post, aperture electric field distributions, and the radiation patterns are discussed. The theoretical analysis is verified by the measured return loss and radiation patterns.

• Advances in nano research
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• 제6권2호
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• pp.147-162
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• 2018

A new nonlocal higher order shear deformation theory (HSDT) is developed for buckling properties of single graphene sheet. The proposed nonlocal HSDT contains a new displacement field which incorporates undetermined integral terms and contains only two variables. The length scale parameter is considered in the present formulation by employing the nonlocal differential constitutive relations of Eringen. Closed-form solutions for critical buckling forces of the graphene sheets are obtained. Nonlocal elasticity theories are used to bring out the small scale influence on the critical buckling force of graphene sheets. Influences of length scale parameter, length, thickness of the graphene sheets and shear deformation on the critical buckling force have been examined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.255-257
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• 1992

The expert system described in this article tunes a proportional-integral-derivative(PID) controller for a single-input single-ouput process. The expert system examines features of each transient response and the corresponding controller parameters. It determines a new set of controller gains to obtain a more desirable time reponse using fuzzy logic. This technique can be used to determine and implement a different set of PID gains for each operating regime and, once in steady state, the system can be used to find optimal parameters for load disturbance rejection.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.995-996
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• 2013

본 연구에서는 스마트폰을 이용하여 사용자의 활동상태를 추정할 수 있는 안드로이드 기반의 어플리케이션을 구현하였다. 이는 추가적인 센서를 사용하지 않고 항시 휴대하는 스마트폰을 이용함으로써 착용형의 시스템과 비교하여 사용자의 불편함을 최소화하여 활동상태를 추정할 수 있다. 이를 위하여 스마트폰 내부에 내장된 3축가속도센서 각 축의 변화량을 추출하였으며, 각 축에 대한 변화량과 활동량이 비례하여 나타나는 것을 이용하여, 변화량을 크기로 변환하는 SVM(Single Vector Magnitude)을 계산하였다. 또한 SVM의 절대값을 시간에 적분한 ISVM(Integral Single Vector Magnitude)을 통해 활동량을 정량화 하였으며, 천천히 걷기와 빠르게 걷기, 뛰기, 서있기로 이루어진 실험을 통해 활통상태 분류를 하였다. 또한 그 결과를 실시간으로 모니터링하기 위한 스마트폰 어플리케이션을 구현함으로써 추가적인 설비 없이 활동상태를 추정하였다.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.194-203
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• 2008

Iterative learning control (ILC) is a simple and effective method for the control of systems that perform the same task repetitively. ILC algorithm uses the repetitiveness of the task to track the desired trajectory. In this paper, we propose a PID (proportional plus integral and derivative) type ILC update law for control discrete-time single input single-output (SISO) linear time-invariant (LTI) systems, performing repetitive tasks. In this approach, the input of controlled system in current cycle is modified by applying the PID strategy on the error achieved between the system output and the desired trajectory in a last previous iteration. The convergence of the presented scheme is analyzed and its convergence condition is obtained in terms of the PID coefficients. An optimal design method is proposed to determine the PID coefficients. It is also shown that under some given conditions, this optimal iterative learning controller can guarantee the monotonic convergence. An illustrative example is given to demonstrate the effectiveness of the proposed technique.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.407-412
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• 1998

A design technique based on the root locus approach for the SISO (Single-Input Single-Output) systems using PID (Proportional-Integral-Derivative) ${\times}$ (n-1) stage PD as a controller for the n$\^$th/ order plant is presented. The controller is designed based on transient and steady state response specifications. This controller can be used instead of a conventional PID controller. The overall system is approximated as a stable and robust second order system. The desired performances are achieved by increase the gain of the controller. In addition, the controller gain can be adjusted to obtain faster response with a little overshoot. The simulation results show the merits of this approach.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.949-952
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• 2000

A low power 10bit current-mode folding and interpolating CMOS analog to digital converter (ADC) with arithmetic folding blocks is presented in this paper. A current-mode two-level folding amplifier with a high folding rate (FR) is designed not only to prevent ADC from increasing a FR excessively, but also to perform a high resolution at a single power supply of 3.3V The proposed ADC is implemented by a 0.6${\mu}$m n-well CMOS single poly/double metal process. The simulation result shows a differential nonlinearity (DNL) of ${\pm}$0.5LSB, an integral nonlinearity (INL) of ${\pm}$1.0LSB