• 한국공작기계학회논문집
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• 제13권2호
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• pp.75-80
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• 2004

Vehicle structures are composed of many substructure connected to one another by various types of mechanical joints. In vehicle engineering it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. It is difficult to obtain the accurate load history of specified positions because of the errors such as modeling, measurement and etc. In the beginning of design exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic force determination is developed by the combination of the principal stresses of F. E. Analysis and experiment. Least square pseudo inverse matrix is adopted to obtain in inverse matrix of analyzed stresses matrix. The error minimization method utilizes the inaccurate measured error and the shifting error that the whole data is stiffed over real data. The least square criterion is adopted to avoid these non. Finally, to verify the proposed procedure, a bus is analyzed. This measurement and prediction technology can be extended to the structural modification of any geometric shape in complex structure.

• 한국공작기계학회논문집
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• 제10권5호
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• pp.118-123
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• 2001

Most structures of automobile are composed of many substructures connected to one another by various types of mechanical joints. In automotive engineering, it is important to study these connected structures under various dynamic farces for the evaluations of fatigue life and stress concentration exactly. It is rarely obtained the accurate load history of specified positions because of the errors such as modeling, measurement, and etc. In the beginning of design, exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic load determination is developed by the combination of the principal stresses of F.E. analysis and experiment. Inverse problem and least square pseudo inverse matrix are adopted to obtain an inverse matrix of analyzed stresses matrix. Pseudo-Practical dynamic load was calculated for Lab. Test of sub-structure. GUI program(PLODAS) was developed for whole of above procedure. This proposed method could be extended to any geometric shape of structure.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.172-176
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• 1989

In this paper, a simple method for designing iterative learning control scheme is proposed. The proposed learning algorithm is designed based on series expansion of inverse plant model. The proposed scheme has simple structure and fast convergency so that it is suitable for implementing it on conventional micro processor based controllers. The effectiveness of the proposed algorithm is investigated through a series of computer simulations.

• 한국해안·해양공학회논문집
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• 제20권4호
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• pp.355-362
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• 2008

경사식 방파제에서 파랑과 구조물의 상호작용에 의하여 발생되는 처오름을 확률론적으로 해석할 수 있는 Level II AFDA 신뢰성 모형이 제안되었다. Level III MCS 모형을 함께 적용하여 본 연구에서 제안된 모형이 만족스럽게 검증되었다. 또한 목표파괴확률과 각 확률변수들의 통계적 특성 그리고 영향계수를 이용하는 역해석 기법을 적용하여 처오름과 관련된 각 확률변수들의 부분안전계수를 산정할 수 있었다. 특히 Level I 신뢰성 설계법을 쉽게 적용할 수 있도록 처오름의 설계기준식을 현행의 결정론적 설계법과 동일한 형태로 유도하였다. 마지막으로 본 연구에서 제시된 부분안전계수를 이용하여 Level I 신뢰성 설계법으로 재 설계한 결과가 CEM(2006) 및 Level II 신뢰성 설계법의 결과와 만족스럽게 비교되었다.

• 응용통계연구
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• 제5권1호
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• pp.1-8
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• 1992

Partitioned matrices를 이용해, v = 2.2.2인 경우의 Hierarchical Group Divisible (HGD) design의 해를 역행렬을 이용하지 아니하고 구하는 방법을 제시하였다.

• Structural Engineering and Mechanics
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• 제88권4호
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• pp.301-309
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• 2023

In this paper, a new modified conjugate gradient (MCG) method is presented which is based on a new gradient regularizer, and this method is used to identify the dynamic load on airfoil structure without and with considering random structure parameters. First of all, the newly proposed algorithm is proved to be efficient and convergent through the rigorous mathematics theory and the numerical results of determinate dynamic load identification. Secondly, using the perturbation method, we transform uncertain inverse problem about force reconstruction into determinate load identification problem. Lastly, the statistical characteristics of identified load are evaluated by statistical methods. Especially, this newly proposed approach has successfully solved determinate and uncertain inverse problems about dynamic load identification. Numerical simulations validate that the newly developed method in this paper is feasible and stable in solving load identification problems without and with considering random structure parameters. Additionally, it also shows that most of the observation error of the proposed algorithm in solving dynamic load identification of deterministic and random structure is respectively within 11.13%, 20%.

• 대한기계학회논문집B
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• 제34권7호
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• pp.679-688
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• 2010

본 연구에서는 기존의 역열전달 문제(inverse heat transfer problem)와 같이 역해석(inverse analysis)을 통해 미지의 파라미터를 추정(estimation)하는 개념을 복잡한 연소문제에 도입하였다. 기존의 연구에서는 역해석 기법을 연소문제 자체에 보다는 대부분 연소현상을 동반한 복사열전달과 같은 역열전달 문제에 국한해서 적용하고 있기 때문에, 열전달 문제에 한정되어 사용되고 있는 기존의 역해석을 새로운 공학문제에 확장하여 적용함과 동시에 효율적인 연소기 설계 및 최적화 개념을 제시하는데 본 연구의 의의가 있다고 할 수 있다. 이를 위해 실제적으로 많이 사용하고 있는 축대칭 원통형 연소기 내부로 주입되는 메탄($CH_4$)과 산소($O_2$) 성분의 초기 질량분율 값을 연소기 입구 근방에서 측정한 개스의 온도 데이터를 이용하여 역추정하였다. 이때, 복잡한 확산지배 연소 현상을 효율적으로 역해석하기 위해 최적화 방법 중의 하나인 반발 입자 군집 최적화 방법을 역해석 기법으로 적용하였다.

• 한국항공우주학회지
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• 제35권2호
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• pp.107-114
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• 2007

논문에서는 두루미-II 무인기 모델을 이용하여 다양한 조종력 할당 기법의 성능을 평가하였다. 조종력 할당 기법은 먼저 조종면 고장을 고려하지 않은 상태에서 대상 항공기의 기준 비행제어 시스템을 설계한 후, 조종력 할당 알고리즘을 결합하여 구현할 수 있다. 본 논문에서 대상 항공기 모델인 두루미-II 무인기의 기준 비행제어 시스템을 고전제어 기법에 근거하여 설계하였다. 그리고 Psuedo-inverse CA 기법과 Direct CA 기법 및 Optimization CA 기법을 구현하여 두루미-II 무인기의 기준 비행제어 시스템과 결합한 후, 조종면 고장 시나리오에 따른 비선형 시뮬레이션을 통해 각 조종력 할당 기법의 성능을 평가하고 비교하였다.

• 대한조선학회지
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• 제7권2호
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• pp.41-60
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• 1970

Despite it's limitations, the existing Stream Line Tracing Method(Inverse Method) can be applied effectively to the design of better hull forms with practical proportions. Most of the calculating mechanism by the method for hull form design has been achieved. In this paper, authors have tried to improve the quality of wave making resistance on the 10,000GT liner among FY'67 Korean Standard Ship Form. Some numerical results obtained in this work and designed new lines are shown.

• Geomechanics and Engineering
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• 제16권6호
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• pp.577-588
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• 2018

A major concern in deep excavation project in soft clay deposits is the potential for adjacent buildings to be damaged as a result of the associated excessive ground movements. In order to accurately determine the wall deflections using a numerical procedure such as the finite element method, it is critical to use the correct soil parameters such as the stiffness/strength properties. This can be carried out by performing an inverse analysis using the measured wall deflections. This paper firstly presents the results of extensive plane strain finite element analyses of braced diaphragm walls to examine the influence of various parameters such as the excavation geometry, soil properties and wall stiffness on the wall deflections. Based on these results, a multivariate adaptive regression splines (MARS) model was developed for inverse parameter identification of the soil relative stiffness ratio. A second MARS model was also developed for inverse parameter estimation of the wall system stiffness, to enable designers to determine the appropriate wall size during the preliminary design phase. Soil relative stiffness ratios and system stiffness values derived via these two different MARS models were found to compare favourably with a number of field and published records.