• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.185-190
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• 2019

This study aims to apply the mathematical method of fractional order derivatives to the controller that controls the system response. In general, the Laplace transform of the PID controller has an exponent of the integer order of s. The derivative of the fractional order has a fractional exponent of s when it is transformed by Laplace transform. Therefore, this controller proposes a design method with the result of discrete time conversion. Because controllers with fractional exponents of s are not easy to design. This controller is applied to a standard secondary system and its performance is examined. Then, it applies to solenoid valve which is widely used in industrial field. A Luenberger's observer was designed to estimate the disturbance state and the observed state was applied to the fractional order controller. As a result, uniform and precise control performance was obtained. It was confirmed that the position error of the steady state is within 0.1 [%] and the rising time is within about 0.03 [s].

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.503-510
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• 2021

This study intends to apply the mathematical method of fractional order differentiation to a controller that controls the response of the system. Therefore, we design integrator for the fractional index by converting it into discrete time to construct a controller. The IP controller composes an integral controller for errors and the proportional controller applies only the system output. The controller is designed by using the fractional order integrator to the integral controller of the IP controller. First, the performance of the PI controller and the IP controller is compared, and the designed controller is applied to the speed control of the motor. As a result, the motor output speed was uniformed and precise control performance could be obtained. It was confirmed that the speed error in the steady state is within 0.1 [%], and it has precise and uniform speed control performance without overshoot.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.101-106
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• 2018

This study proposes a method of controller design for precise position control in the use of solenoid which is widely used in industrial field. First, we design a Luenberger's observer that can accurately estimate the disturbance and set the appropriate gain. Based on the observed state, a fractional PD controller is designed and applied to the position control. As a result, the fractional order controller can obtain almost the same control performance even if the target position is different. In addition, it was confirmed that the position error of the steady state is within 0.1 [%] and the rising time is within about 0.05 second.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.113-119
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• 2006

Recently, the ground injection method using water glasses as one of the main resources and the products of these constructions have basic problems in terms of the method of constructions for the permanent foundation reinforcement and stopping leakage of water because they have some serious problems such as durability, compressive strength, injectant eluviation and so forth even though they are still used to stop leakage of water in the temporary structures. The purpose of this study is to demonstrate the strength characteristic and environment friendliness of NDS method by unconfined compressive strenth test, permeability test, length change test, leaching test, and assessment of environmental impact in comparison water glass type material. The test results show that NDS method has significant improvement of strength, permeability, volume change, and leaching. An assessment of environmental impact also demonstrates that the NDS material is environmentally friendly.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.625-628
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• 2002

디지틸워터마킹은 디지털콘텐츠의 저작권보호 솔루션으로서 현재 주로 이미지, 오디오, 비디오, 텍스트 등을 대상으로 연구되고 있다. 컴퓨터 하드웨어, 네트워크, 그리고, 응용 소프트웨어의 빠른 발전과 함께 국가 차원의 초고속 통신망의 인프라 구축에 힘입어, 3차원 폴리곤과 곡선 및 곡면에 대한 디지털워터마킹에 관심이 높아지고 있다. 본 논문에서는 유리 베지에곡선에 대한 디지털워터마킹에 대한 하나의 방법을 제시한다. 기존의 베지에곡선의 차수를 증가시키는 일반적인 방법이 아닌 유리항의 분모와 분자에 공통의 다항식을 곱하여 차수를 증가시킨다. 이때 공통으로 칠하는 다항식의 관들의 복비(cross ratio) 값에 우리가 숨기고자하는 마크를 삽입하고, 추출해내는 방법을 제시한다. 본 논문에서 제시된 알고리듬은 워터마크를 삽입하는 과정에서 곡선의 형태를 전혀 변화시키지 않는 형태 유지성(shape preserving property)을 갖는다. 또한. 본 알고리듬의 다른 중요한 특징은 곡선이 CAD 시스템에 의해 이용되는 과정에서 흔히 일어나는 재매개화 방법 중 뫼비우스 변환을 이용한 재매개화에 저항성이 있는 알고리듬이라는 것이다. 마지막으로 본 연구에서 제시한 방범에 의한 예제의 결과를 보여준다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.153-156
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• 2000

본문에서는 예측형 회귀신경망과 HMM의 하이브리드 네트워크인 회귀신경망 예측 HMM을 구성하였다. 회귀신경망 예측 HMM은 예측형 회귀신경망을 HMM의 각 상태마다 예측기로 정의하여 일정치인 평균벡터 대신에 과거의 특징벡터의 영향을 받아 동적으로 변화하는 신경망에 의한 예측치를 이용하므로 학습패턴 설정자체가 시변성을 반영하는 동적 네트워크의 특성을 가진다. 따라서 음성과 같은 시계열 패턴의 인식에 유리하다. 회귀신경망 예측 HMM은 예측형 회귀신경망의 구조에 따라 Elman망 예측 HMM과 Jordan망 예측 HMM으로 구분하였다. 실험에서는 회귀신경망 예측 HMM의 상태수를 4, 5, 6으로 증가시켜 각 상태 수별로 예측차수 및 중간층 유니트 수의 변화에 따른 인식성능을 조사하였다. 실험결과 평가용. 데이터에 대하여 Elman망예측 HMM은 상태수가 6이고, 예측차수가 3차, 중간층 유니트의 수가 15차원일 때, Jordan망 예측 HMM의 경우 상태수가 5이고, 예측차수가 3차, 중간층 유니트의 수가 10차원일 때 각각 99.5%로 우수한 결과를 얻었다.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.1
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• pp.1-8
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• 2005

This paper presents the experimental results measured by photoelastic 4-step phase shifting method for the isochromatic fringe distribution in a TV glass panel. In the conventional photoelastic method, the isochromatic fringe orders are measured manually point by point. The 4-step phase shifting method uses four images obtained from a circular polariscope by rotating the analyzer to $0^{\circ},\;45^{\circ},\;90^{\circ}$, and $135^{\circ}$. In order to use the 4-step phase shifting method, the elements of a polariscope should be aligned to isoclinic direction at a point and/or along a line where isochromatic fringe distribution is measured. Experimental results obtained from the 4-step phase shifting method are compared with those measured by the Senarmont compensation method. Both results are well agreed. Then, isochromatic fringe distributions in the TV glass panel that is heat-treated before and after are compared. Maximum and minimum isochromatic fringe orders in the TV glass panel with before- and after-heat treatment are changed approximately two times.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.109-116
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• 2010

The Water glass grouting method has been applied frequently to penetration grouting in practice, but some problems, such as decrease of durability with the elapsed time and environmentally adverse effect, are raised recently. Hence, the Earth Natural Grouting method which uses micro cement and inorganic material is developed to overcomes those problems of the water glass grouting method, and is aimed for extensive ground injection bound. Volumetric strain test, syneresis test, unconfined compression test, triaxial permeability test, in-situ permeability test and heavy metal analysis were conducted to verify application of the ENG. As the result of tests, volumetric strain, syneresis and unconfined strength of the ENG were superior to those of the Water Glass SGR and ENG was proved to be impermeable. Also it is expected that the ENG would not have an effect on environmental pollution.

• 대한생식의학회:학술대회논문집
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• 2004.11a
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• pp.34-34
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• 2004

• Journal of the Society of Disaster Information
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• v.9 no.4
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• pp.462-468
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• 2013

Walls for preventing floods using overturning or buoyancy method have been developed as replacement construction for preventing floods in and outside country. However, as they have some problems with pre-inspection and maintenance control, Eco-moving wall structure for preventing floods was studied and first developed using Glass Fiber Reinforced Composite which has not only light weight but outstanding strength. The developed wall structure for preventing floods offering structural stability and field applicability through numerical analysis was confirmed to reduce construction expenses by around 87~95% and secure waterproof property with the inside of the wall installed rubber water stopper.