• Steel and Composite Structures
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• 제43권1호
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• pp.129-137
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• 2022

Dynamic response of a laminated porous concrete beam reinforced by nanoparticles subjected to harmonic transverse dynamic load is investigated considering structural damping. The effective nanocomposite properties are evaluated on the basis of Mori-Tanaka model. The concrete beam is modeled by the sinusoidal shear deformation theory (SSDT). Utilizing nonlinear strains-deflection, energy relations and Hamilton's principal, the governing final equations of the concrete laminated beam are calculated. Utilizing differential quadrature method (DQM) as well as Newmark method, the dynamic displacement of the concrete laminated beam is discussed. The influences of porosity parameter, nanoparticles volume percent, agglomeration of nanoparticles, boundary condition, geometrical parameters of the concrete beam and harmonic transverse dynamic load are studied on the dynamic displacement of the laminated structure. Results indicated that enhancing the nanoparticles volume percent leads to decrease in the dynamic displacement about 63%. In addition, with considering porosity of the concrete, the dynamic displacement enhances about 2.8 time.

• Design & Manufacturing
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• 제16권4호
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• pp.60-66
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• 2022

Recently, with the development of industry and the improvement of living standards, various wastes are generated along with the production of various products. Most of these wastes are used as containers for products, and plastic or aluminum is used. Various attempts are being made to automate the classification of these wastes due to the high labor cost, but most of them are solved by manpower due to the geometrical shape change due to the nature of the waste. In this study, in order to automate the waste sorting task, Deep Learning technology is applied to a robot system for waste sorting and a vision system for waste sorting to effectively perform sorting tasks according to the shape of waste. As a result of the experiment, a Deep Learning parameter suitable for waste sorting was selected. In addition, through various experiments, it was confirmed that 99% of wastes could be selected in individual & group image learning. It is expected that this will enable automation of the waste sorting operation.

• Steel and Composite Structures
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• 제49권3호
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• pp.349-359
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• 2023

Dynamic response and economic of a laminated porous concrete beam reinforced by nanoparticles subjected to harmonic transverse dynamic load is investigated considering structural damping. The effective nanocomposite properties are evaluated on the basis of Mori-Tanaka model. The concrete beam is modeled by the sinusoidal shear deformation theory (SSDT). Utilizing nonlinear strains-deflection, energy relations and Hamilton's principal, the governing final equations of the concrete laminated beam are calculated. Utilizing differential quadrature method (DQM) as well as Newmark method, the dynamic displacement of the concrete laminated beam is discussed. The influences of porosity parameter, nanoparticles volume percent, agglomeration of nanoparticles, boundary condition, geometrical parameters of the concrete beam and harmonic transverse dynamic load are studied on the dynamic displacement of the laminated structure. Results indicated that enhancing the nanoparticles volume percent leads to decrease in the dynamic displacement about 63%. In addition, with considering porosity of the concrete, the dynamic displacement enhances about 2.8 time.

• Geomechanics and Engineering
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• 제36권4호
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• pp.407-416
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• 2024

Dynamic response of a rock tunnels by laminated porous concrete beam reinforced by nanoparticles subjected to harmonic transverse dynamic load is investigated considering structural damping. The effective nanocomposite properties are evaluated on the basis of Mori-Tanaka model. The concrete beam is modeled by the exponential shear deformation theory (ESDT). Utilizing nonlinear strains-deflection, energy relations and Hamilton's principal, the governing final equations of the concrete laminated beam are calculated. Utilizing differential quadrature method (DQM) as well as Newmark method, the dynamic displacement of the concrete laminated beam is discussed. The influences of porosity parameter, nanoparticles volume percent, agglomeration of nanoparticles, boundary condition, geometrical parameters of the concrete beam and harmonic transverse dynamic load are studied on the dynamic displacement of the laminated structure. Results indicated that enhancing the nanoparticles volume percent leads to decrease in the dynamic displacement about 63%. In addition, with considering porosity of the concrete, the dynamic displacement enhances about 2.8 time.

• 한국소음진동공학회논문집
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• 제23권3호
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• pp.199-208
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• 2013

So far today, there is a speed limit by the radius of curve based on operation regulation in domestic railway, however a study for the maximum running speed at the curved section without any derailment would be necessary. The two major factors related to the running safety of railway vehicle are classified as the railway vehicle condition and the track condition. In terms of the rail inclination among many other factors, the determination of rail inclination within the possible limit is necessary for the geometrical structure of the optimum track. The disregard of the geometrical parameter related to the rail inclination may cause a serious problem to the running safety of railway vehicle. This study is focusing on the analyzing of running safety regard to the change of rail inclination among the many other parameters to improve derailment safety, so that there is an affection analysis of the running safety regard to the change of rail inclination in the ideal and geometric track condition. Also There is an affection analysis of the running safety regard to the simultaneous change of rail inclination and the running speed at the curved section. According to analysis results of running safety, In case that the left and right rail inclination are 1/40, the running safety of this condition defined than other conditions. Also, the rail inclination of conventional lines is 1/40, Therefore, the railway vehicle passing through curve is safe when the railway vehicle runs in conventional lines.

• Journal of Welding and Joining
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• 제12권1호
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• pp.59-72
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• 1994

This paper presents an on-line quality monitoring and control method to obtain a uniform weld quality in gas metal arc welding (GMAW) processes. The geometrical parameters of the weld pool such as the top bead width and the penetration depth plus half back width are utilized to assess the integrity of the weld quality. Since a good quality weld is characterized by a relatively high depth-to-width ratio in its dimensions, the second geometrical parameter is regulated to a desired one. The monitoring variables are the surface temperatures measured at various points on the top surface of the weldment which are strongly related to the formation of the weld pool The relationship between the measured temperatures and the weld pool size is implemented on the multilayer perceptrons which are powerful for realization of complex mapping characteristics through training by samples. For on-line quality monitoring and control, it is prerequisite to estimate the weld pool sizes in the region of transient states. For this purpose, the time history of the surface temperatures is used as the input to the neural estimator. The control purpose is to obtain a uniform weld quality. In this research, the weld pool size is directly regulated to a desired one. The proposed controller is composed of a neural pool size estimator, a neural feedforward controller and a conventional feedback controller. The pool size estimator predicts the weld pool size under growing. The feedforward controller compensates for the nonlinear characteristics of the welding process. A series of simulation studies shows that the proposed control method improves the overall system response in the presence of changes in torch travel speed during GMA welding and guarantees the uniform weld quality.

• 대한기계학회논문집B
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• 제34권10호
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• pp.893-899
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• 2010

박동유동조건에서 관상동맥 내의 유동특성과 혈류역학적 인자 분포를 선행연구에서 수행하여 혈류역학이 관상동맥 내의 협착현상과 연관관계가 있음을 밝혔다. 동맥경화증의 호발부위인 관상동맥 분지부에서 혈류역학적 변수를 분석하여 동맥경화증의 발생기전을 규명하는 것이 본 연구의 목적이다. 동맥경화증에 의한 협착현상은 혈액과 혈관벽 사이의 생화학 반응뿐 아니라 유동박리나 벽전단응력과 같은 혈류역학적 인자와도 관계 있음을 확인하였다. 관상동맥 분지부의 분지각이 증가할수록 분지부 단면에서의 재순환영역의 크기가 증가하고 교란유동이 발생하게 된다. 이 재순환영역이 관상동맥에서 동맥경화의 시작점으로 의심되는 영역이라 할 수 있다.

• 전자공학회논문지
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• 제51권8호
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• pp.30-37
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• 2014

본 논문에서는 실제 공정을 반영한 FinFET의 게이트 저항 압축모델을 개발하였다. 삼차원 소자 시뮬레이터 Sentaurus를 사용하여, Y-parameter 해석 방법을 적용하여 게이트 저항을 추출하여 제안하는 모델을 검증하였다. FinFET 게이트의 전기장이 수평 수직 방향으로 형성됨을 고려하여 모델링함으로써, FinFET 게이트 저항의 비선형성을 반영하였다. 현재 제작되고 있는 FinFET에서 게이트가 두 물질(Tungsten, TiN)로 적층된 구조일 수 있음을 고려하여, 비저항이 서로 다른 물질을 적층 시킨 구조에 대한 압축 모델을 개발하였다. 제안하는 모델을 사용하여, 게이트의 기하학적 구조 변수 변화에 따른 게이트 저항이 최소가 되는 fin의 수를 제안하였다. BSIM-CMG에 제안하는 모델을 구현한 후, ring-oscillator를 설계하고, 게이트 저항이 고려되지 않았을 때와 고려되었을 때의 각단의 신호지연을 회로 시뮬레이터를 통해 비교하였다.

• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.28-31
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• 2016

본 연구에서는 최근 의료용으로 많이 사용되고 있는 고휘도, 고균일도의 직하광원구조를 가지는 백라이트 유닛에 대한 설계 시뮬레이션을 실시하였다. 직하형 백라이트 시스템은 기존의 Edge-Lighr 방식에 비해서 고휘도 및 고균일도를 달성할 수 있어 의료용 판독이 요구되는 고품질의 디스플레이에 사용되고 있으며, 흑백이미지를 바탕으로 진단을 실시하는 경우가 많기 때문에 휘도 및 휘도 균일도에 대한 높은 성능이 요구되는 분야이다. 본 연구에서는 복수 개의 램프를 수평으로 배열한 경우에 각 램프간의 거리 및 반사판과의 거리, 상측 확산판과의 거리에 대한 최적설계를 실시하고, 이 결과를 바탕으로 실물과 유사한 조건에서 시뮬레이션을 실시하였다. 연구 결과, Parameter 에 의존하는 변수를 최적화 할 수 있었으며, 4.5mm 의 램프와 반사판 거리 및 26mm 의 램프간 거리를 바탕으로 16개의 램프를 배치하여, 32인치 크기의 화면에서 6423nit 의 중심휘도를 갖는 고품위의 우수한 광원의 설계가 가능함을 확인할 수 있었다.

• 한국멀티미디어학회논문지
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• 제3권1호
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• pp.23-33
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• 2000

본 논문에서는 복잡한 배경으로부터 자연스런 상태로 촬영된 얼굴들을 검출하는 알고리듬에 대해 기술한다. 이 방법은 얼굴영역이 적당한 크기의 블록내에서는 비교적 비슷한 밝기는 지닌다는 점에 착안하였다. 이 사실을 근거로, 먼저 영상을 계층적으로 블록화하고, 블록들의 밝기가 서로 비슷한 영역을 신속히 얼굴후보로 선택하여, 후보영역내에서 구체적인 얼굴특징을 찾는 단계적 처리방법을 도입하였다. 후보영역내의 구체적인 특징추출을 위해서 어둡고 좁은 영역을 강조하는 국소 휘도치 변환법을 사용하였으며 최종 판단을 위해서는 얼굴의 각 기관이 갖는 삼각형의 배치구조를 제약으로 사용하였다. 매우 간단한 방법으로 얼굴영역을 처리하였기 때문에 특징점들을 추출할 때 생기는 파라메터 설정문제를 피할수 있고 그 결과 파라메터값에 크게 의존하지 않는 안정된 시스템 구현이 가능하다.