• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.220-227
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• 2002

This paper describes an integrated approach process to carry out pre-test, model correlation and updating analysis on the sub-frame of a vehicle. In this study, it was found that the modal test could be more efficient when the exciting point was selected on the area with high driving point residue. Such area could be located with the aid of finite element modal analysis. The model correlation was appraised in conjunction with the modal parameters between modal test and finite elements analysis. Also, the finite element model updating was obtained the good resultant using the iteration method based on sensitivity analysis results that carried out the variation of natural frequencies and MAC for the material properties. Finally, optimization of vehicle subframe was carried out the analysis of core location and physical properties by tow steps.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.457-464
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• 2011

This paper deal with the validation of correction method of ice strength and thickness to the sea trial condition based on the ice model test results. It is very difficult to conduct the model test corresponding to the sea trial condition exactly. In addition, the available sea trial data is not sufficient for the validation of correction method. In the present study, the model test results of Terry-Fox ice breker have been used to compare the corrected results of sea trial test by varying its thickness and strength of model ice. The HSVA and ITTC methods have been applied to the present comparisions and the required power has been also validated by using the HSVA method. There are rather good agreement between the sea trial result and model test corrected by the HSVA and ITTC method. The more comparisons are expected to be carried out in near future.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.198-203
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• 1995

The objective of this study is to provide the information on the techniques of manufacturing and experiment in small scale modeling of precast concrete(P.C.)large panel structures. The adopted scale was 1/5th 4types of experiments were performed : material tests for model concrete and model reinforcement, compressive test of horizontal joint, shear test of vertical joint and cyclic static test of 2-story subassemblage structure. Based on the experimental results, the following conclusions are drawn: (1)Model concrete may have in general larger compressive strength than expected. (2) Model reinforcement can show less ductility if the annealing processes were performed without using vaccuum tube. (3) Failure modes of horizontal and vertical joints were almost same for both prototype and model. But the strength of model appears to be higher than required by similitude law. (4)Hysteretic behavior of 1/5 scale subassemblage model can be made quite similar to prototype's if the ductility of model reinforcement and compressive strength of model concrete could be representative of those of prototype.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.583-585
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• 2001

RUP의 Unified Process Model 에는 Use-Case Model, Analysis Model, Design Model, Deployment Model, Implementation Model, Test Model의 6가지 모델이 있다. 이 모델들은 모두 일관성이 있다. 한 모델에서 나오는 요소들은 전, 후 단계에서 다른 모델들과 Trace Dependencies를 갖는다. 예를 들면, Use-Case Model에서는 한 Use Case는 Design Model에서 Use-Case Realization으로 Test Model에서는 Test Case로 Trace Dependencies를 갖는다. 소프트웨어 개발에서 추적성은 Understandability와 Change Propagation 과 같은 이유로 매우 중요하다. 그러나 RUP에서는 각 모델들간의 추적성에 대한 지침이 충분히 제시되어 있지 않아, 개발 과정중에 요구사항의 변경이나 에러 수정 또는 향후 관리 시에 어려움을 겪고 있다. 본 논문에서는 이 점에 중점을 두고 RUP에서 제시하고 있는 모델들 간의 추적성 중 설계모델에서 분석모델로의 추적성 적용지침을 제시한다.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.109-116
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• 2010

It is important to make a mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structure dynamics. In finite element analysis model updating is appropriate as the design parameter is used to analyze the dynamic system. The errors can be contained from the physical parameters and the element modeling. From the dynamic test, more precise dynamic characteristics can be obtained. In this paper, model updating algorithm is developed using frequency difference between experiment and calculation. Modal frequencies are obtained by experiment and finite element analysis for beams with various cross section and shapes which have added masses and holes in the middle. For plates with and without groove, experiment and analyses are carried out by applying free boundary conditions as well. Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies in case that both matrices are updated. An improved analytical model is obtained by changing model parameters such that the discrepancy between test and finite element frequencies is minimized. For beam and plate models updating of mass and stiffness matrices can improve the dynamical behavior of the model by acting on the physical parameters such as masses and stiffness.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.456-463
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• 2009

The preconsolidation pressure has been commonly determined by oedometer test. However, it can also be determined by in-situ test, such as piezocone test with theoretical and(or) empirical correlations. Recently, Neural Network(NN) theory was applied and some models were proposed to estimate the preconsolidation pressure or OCR. However, since the optimization process of synaptic weights of NN model is dependent on the initial synaptic weights, NN models which are trained with different initial weights can't avoid the variability on prediction result for new database even though they have same structure and use same transfer function. In this study, Committee Neural Network(CNN) model is proposed to improve the initial weight dependency of multi-layered neural network model on the prediction of preconsolidation pressure of soft clay from piezocone test result. It was found that even though the NN model has the optimized structure for given training data set, it still has the initial weight dependency, while the proposed CNN model can improve the initial weight dependency of the NN model and provide a consistent and precise inference result than existing NN models.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1577-1584
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• 2002

This paper develops a finite element model for studying the occupant behavior and injury cofficients of a large-sized cab-over type truck. Since it does not have a room to absorb collision energy and deformation in front of the passenger compartment the deformation is directly transmitted to the passenger compartment. Moreover, since its steering column is attached on the frame, severe deformation of the frame directly affects on the steering wheel's movement. Therefore, if the occupant behavior and injury coefficients analysis is performed using a finite element model developed based on a sled test, it is very difficult to expect acquiring satisfactory results. Thus, the finite element model developing in this paper is based on the frontal crash test in order to overcome the inherent problems of the sled test based model commonly used in the passenger car. The occupant behavior and injury coefficients analysis is performed using PAM-CRASH installed in super-computer SP2. In order to validate the reliability of the developed finite element model, a frontal crash test is carried out according to a test method used fur developing truck occupant's secondary safety system in european community and japan. That is, test vehicle's collision direction is vertical to the rigid barrier and collision velocity is 45kph. Thus, measured vehicle pulses at the lower parts of the left and right B-pilla., dummy chest and head deceleration profiles, HIC(head injury criterial) and CA(chest acceleration) values, and dummy behavior from the frontal crash test are compared to the analysis results to validate reliability of the developed model.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.8
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• pp.385-390
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• 2017

Because of the ever-increasing software complexity, model-based development techniques are becoming an essential technique in software development. However, even if model-based techniques are used, the test case generation for complex software is still a challenge to solve. In this paper, we propose a method to generate automatic test cases based on UML model using custom parser and SMT solver. By proposed technique, a test case can be generated even though the model is described in a platform independent language such as action language, or in a platform dependent language. In addition, a concolic execution technique is applied to efficiently generate test cases in the model. In this paper, we present a case study on the power window switch model of Hyundai Santa Fe through the proposed test case generation technique.

• The KIPS Transactions:PartD
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• v.17D no.2
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• pp.147-156
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• 2010

Conformance testing for embedded software is to check whether software was correctly implemented according to software specification or not. In conformance testing, test scenarios must be extracted to cover every test cases of software. In a general way, test scenarios simply focus on testing all functions at least one time. But, test scenarios are necessary to consider efficiency of test execution. In this paper, we propose a test scenario extraction method by considering function's execution time and waiting time for user interaction. A test model is a graph model which is generated from state machine diagram and test cases in software specification. The test model is augmented by describing test execution time and user interaction information. Based on the test model, test scenarios are extracted by a modified Dijkstra's algorithm. Our test scenario approach can reduce testing time and improve test automation.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.77-80
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• 1997

In this paper presented is a temperature controller for a semiconductor test handler. Using ARMAX model and least square method, the chamber model for the design of a controller is identified through experiment. With the identified model an LQG/LTR controller is designed. Experiment with a real test handler demonstrated good performance in that its overshoot is small and response time is fast.