• KIPS Transactions on Software and Data Engineering
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• v.2 no.7
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• pp.471-478
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• 2013

This paper proposes a black-box based test case generation method for Simulink/Stateflow model utilizing the RRT algorithm which is a method to efficiently solve the path planning for complicated systems. The proposed method in the paper tries to solve the reachability problem with the RRT algorithm, which has to be solved for black-box based test case generations. A major problem of the RRT based test case generation algorithms is that the cost such as running time and required memory size is too much for complicated Stateflow model. The typical RRT algorithm expands rapidly-exploring random tree (RRT) in a single state space. But the proposed method expands it in dynamic state space based on the state of Simulink model, consequently reducing the cost. In the paper, a new definition of RRT state space, a distance measure and a test case generation algorithm are proposed. The performance of proposed method is verified through the experiment against Stateflow model.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.559-564
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• 2016

The Durbin-Watson (DW) test in regression model and the Ljung-Box (LB) test in ARMA (autoregressive moving average) model are typical examples of correlated error tests. The DW test is used for detecting autocorrelation of errors using the residuals from a regression analysis. The LB test is used for specifying the correct ARMA model using the first some sample autocorrelations based on the residuals of a tted ARMA model. In this article, simulations with four data generating processes have been carried out to evaluate their performances as correlated error tests. Our simulations show that the DW test is severely dependent on the assumed AR(1) model but isn't sensitive enough to reject the misspecified model and that the LB test reports lackluster performance in general.

• 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.

• Journal of the Korean Statistical Society
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• v.25 no.3
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• pp.347-358
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• 1996

A new test for goodness-of-fit is presented. It is a modification of a test of LaRiccia (1991). These tests are applicable to continuous lo-cation/scale models. The new test statistic is based on a few selected order statistics taken from the sample, while the LaRiccia test is based directly on the full sample. Each test embeds the hypothesized model in a larger linear model and proceeds to test the goodness-of-fit hy-pothesis by testing the coefficients of this linear model appropriately. The general theory is presented. The tests are compared via computer simulation to a related test of Ali and Umbach (1989) for distributions that could be used as lifetime models. An important aspect of all these tests is that only standard $X_2$ tables are used. Selection of the spacings of the order statistics is discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.853-858
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• 2003

The suitable estimation of the filter width in the dynamic eddy viscosity model were investigated in high Reynolds number channel flow. In this study, the improvement on matters by optimizing the test filter shape was attempted through the numerical experiment. The way that select optimum test filter width is recommended. Some test filters, one is based on a discrete representation of the top-hat filter and another are based on a high-order filtering operation, are evaluated in simulations of the turbulent channel flow at Reynolds number 1020, based on friction velocity and channel half width. It appears that the estimation of test filter width practically can decrease the dissipative nature of dynamic eddy viscosity model with explicit test filter. It shows that the value of the filter width ratio used in the dynamic procedure must match the properties of the test filter actually used in the calculation.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.829-840
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• 2013

This paper proposes a modified RRT (Rapidly exploring Random Tree) algorithm utilizing a heuristic input analysis and suggests a test case generation method from Simulink/Stateflow model using the proposed RRT algorithm. Though the typical RRT algorithm is an efficient method to solve the reachability problem to definitely be resolved for generating test cases of model in a black box manner, it has a drawback, an inefficiency of test case generation that comes from generating random inputs without considering the internal states and the test targets of model. The proposed test case generation method increases efficiency of test case generation by analyzing the test targets to be satisfied at the current state and heuristically deciding the inputs of model based on the analysis during expanding an RRT, while maintaining the merit of RRT algorithm. The proposed method is evaluated with the models of ECUs embedded in a commercial passenger's car. The performance is compared with that of the typical RRT algorithm.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.137-140
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• 2000

In this paper, we have proposed an efficient test generation method for asynchronous circuits. The test generation is based on specification level, especially on Signal Transition Graph(STG)〔1〕 which is a kind of specification method for asynchronous circuits. To conduct a high-level test generation, we have defined a high-level fault model, called single State Transition Fault(STF) model on STG and proposed a test generation algorithm for STF model. The effectiveness of the proposed fault model and its test generation algorithm is shown by experimental results on a set of benchmarks given in the form of STG. Experimental results show that the generated test for the proposed fault model achieves high fault coverage over single input stuck-at fault model with low cost. We have also proposed extended STF model with additional gate-level information to achieve higher fault coverage in cost of longer execution time.

• International Journal of Reliability and Applications
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• v.6 no.1
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• pp.31-39
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• 2005

An economic life test sampling plan for products with exponential lifetime distribution is developed. To reduce test time, a test plan with curtailed Type II censoring is considered. A cost model is constructed which involves three cost components; test cost, accept cost, and reject cost. Determination of optimal plan minimizing the expected average cost per lot is discussed with a constraint related to consumer's risk. Some numerical examples are provided.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.855-860
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• 2007

This paper describes a human driver model developed based on finite preview optimal control method. The human driver steering model is constructed to minimize a performance index which is a quadratic form of lateral position error, yaw angle error and steering input. Simulation studies are conducted using a vehicle simulation software, Carsim. The Carsim vehicle model is validated using vehicle test data. In order to validate the human driving steering model, the human driver steering model is compared to the driving data on a virtual test track(VTT) and the actual vehicle test data. It is shown that human driver steering behaviors can be well represented by the human driver steering model presented in this paper

• Wind and Structures
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• v.20 no.6
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• pp.719-737
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• 2015

Full scale measurement on the structural dynamic characteristics and Vortex-induced Vibrations (VIV) of a long-span suspension bridge with a central span of 1650 m were conducted. Different Finite Element (FE) modeling principles for the separated twin-box girder were compared and evaluated with the field vibration test results, and the double-spine model was determined to be the best simulation model, but certain modification still needs to be made which will affect the basic modeling parameters and the dynamic response prediction values of corresponding wind tunnel tests. Based on the FE modal analysis results, small-scaled and large-scaled sectional model tests were both carried out to investigate the VIV responses, and probable Reynolds Number effects or scale effect on VIV responses were presented. Based on the observed VIV modes in the field measurement, the VIV results obtained from sectional model tests were converted into those of the three-dimensional (3D) full-scale bridge and subsequently compared with field measurement results. It is indicated that the large-scaled sectional model test can probably provide a reasonable and effective prediction on VIV response.