• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.555-560
• /
• 2003

Korean High Speed Train(KHST) has been tested on the high speed test line in Osung site of Korea High Speed Rail Construction Authority (KHRC). since it was developed as G7 Project Plan In 2002. This paper introduces the dynamic test devices in KHST and shows the comparison between the results of test and theoretical computing results which derive from the new model for KHST dynamic behavior. Previous computer simulation model for KHST was developed to review wether the vehicle system was satisfied with the dynamic performance requirements during the design procedure. But It should be applied the results of the parts test for suspension elements in order to compare between the results of computation and real test. Using VAMPIRE Program made by AEA Technology in UK. the new model also was modified. This paper shows that the static wheel loads calculated from new model is similar to test results. For test on high speed line, we prepared the test devices for evaluating the dynamic performances. which was consisted of the accelerometers( based on Kisler Co.) and the data aquisition systems (based on National instrument Co.), and test program coded by LabView 6i program. These lest devices and programs are flexible to extension the channels for adding sensors and connect to the ethernet network. The acceleration of car bodies, bogie frames and axle boxes were compared between the results of computation and test at 150km/. This paper shows that the results of test were high in high frequency band range but similar frequency band range. It might be considered that these differences were caused by the test which did not performed at constant speed for comparison analysis. Also. It will be able to understand the differences and make better results through a lot of tests planed in future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.7
• /
• pp.275-283
• /
• 2017

The purpose of this study is to investigate the evaluation scores among various evaluators such as tutor, peer, and self evaluation, the lenience and central tendency among these various evaluators, and the correlation between evaluation scores among the various evaluators and the paper test score in the Problem-Based Learning (PBL). For the research, tutor, peer, and self evaluations were carried out with PBL effectiveness evaluation tool for the 105 nursing students taking classes using PBL, and paper test was conducted after the PBL class ended. The collected data were analyzed by SPSS WIN (V. 12.0). The study results showed that peer and self evaluation scores were higher than tutor evaluation score. Also lenience and central tendency were higher and stronger in peer and self evaluation than in tutor evaluation. Paper test score had a significant correlation with tutor evaluation score, but not with peer or self evaluation scores.

• Journal of the Korean Chemical Society
• /
• v.65 no.1
• /
• pp.48-57
• /
• 2021

This study analyzed the science assessment items that were conducted by the paper and the computer-based assessment in the TIMSS 2019 pre-test, which is an international academic achievement assessment. We examined whether the test mode influenced the percentage of items answered correctly by each graders. As a result, there was no significant difference in the correct answer rates of science items according to the test media in 4th and 8th graders. Looking at the each graders, the difference in the percentage of correct answers was relatively large in the fourth grader rather than the eighth grader. In terms of items, the difference in the percentage of correct answers was relatively larger for the constructed items than the multiple choice questions. As a result of analyzing the content of science and assessment items on the influence of the test media, the multiple choice items showed little difference between the paper and the computer-based assessment items, but the answer-type items tended to have a lower percentage of correct answers than the paper-based assessment. In addition, by grade, 4th graders showed lower percentages of correct answers in the constructed items than 8th graders. This study provides implications related to the development and introduction of computer-based assessment in Korea, and suggests an educational implications for computer-based assessment to be well established as school evaluation.

• Journal of Information Processing Systems
• /
• v.14 no.3
• /
• pp.607-620
• /
• 2018

The problem surrounding methods of implementing the software testing process has come under the spotlight in recent times. However, as compliance with the software testing process does not necessarily bring with it immediate economic benefits, IT companies need to pursue more aggressive efforts to improve the process, and the software industry needs to makes every effort to improve the software testing process by evaluating the Test Maturity Model integration (TMMi). Furthermore, as the software test process is only at the initial level, high-quality software cannot be guaranteed. This paper applies TMMi model to Automobile control software testing process, including test policy and strategy, test planning, test monitoring and control, test design and execution, and test environment goal. The results suggest improvement of the automobile control software testing process based on Test maturity model. As a result, this study suggest IT organization's test process improve method.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.1
• /
• pp.179-183
• /
• 2010

In this paper, we consider the change point problem in diusion processes based on discretely observed sample. Particularly, we consider the change point test for the dispersion parameter when the drift has unknown parameters. In performing a test, we employ the cusum of squares test based on the residuals. It is shown that the test has a limiting distribution of the sup of a Brownian bridge. A simulation result as to the Ornstein-Uhlenbeck process is provided for illustration. It demonstrates the validity of our test.

• 한국데이터정보과학회:학술대회논문집
• /
• 2006.04a
• /
• pp.279-293
• /
• 2006

In this paper, we derive the approximate maximum likelihood estimators of the scale parameter and location parameter of the exponential distribution based on multiply Type-II censored samples. Then three type tests, including the modified Clamor-von Mises test, the modified Watson test and the modified Kolmogorov-Smirnov test are developed for the exponential distribution based on multiply Type-II censored samples by using the proposed estimators. For each test, Monte Carlo techniques are used to generate critical values. The powers of these tests are investigated under several alternative distributions.

• Journal of the Korean Data and Information Science Society
• /
• v.11 no.2
• /
• pp.201-215
• /
• 2000

The classical method for regression analysis is the least squares method. However, if the data contain significant outliers, the least squares estimator can be broken down by outliers. To remedy this problem, the robust methods are important complement to the least squares method. Robust methods down weighs or completely ignore the outliers. This is not always best because the outliers can contain some very important information about the population. If they can be detected, the outliers can be further inspected and appropriate action can be taken based on the results. In this paper, I propose a sequential outlier test to identify outliers. It is based on the nonrobust estimate and the robust estimate of scatter of a robust regression residuals and is applied in forward procedure, removing the most extreme data at each step, until the test fails to detect outliers. Unlike other forward procedures, the present one is unaffected by swamping or masking effects because the statistics is based on the robust regression residuals. I show the asymptotic distribution of the test statistics and apply the test to several real data and simulated data for the test to be shown to perform fairly well.

• International Journal of Computer Science & Network Security
• /
• v.23 no.1
• /
• pp.103-111
• /
• 2023

Implementing conventional DFT solution for arrays of DNN accelerators having large number of processing elements (PEs), without considering architectural characteristics of PEs may incur overwhelming test overheads. Recent DFT based techniques have utilized the homogeneity and dataflow of arrays at PE-level and Core-level for obtaining reduction in; test pattern volume, test time, test power and ATPG runtime. This paper reviews these contemporary test solutions for ASIC based DNN accelerators. Mainly, the proposed test architectures, pattern application method with their objectives are reviewed. It is observed that exploitation of architectural characteristic such as homogeneity and dataflow of PEs/ arrays results in reduced test overheads.

• Journal of the Korean Statistical Society
• /
• v.33 no.4
• /
• pp.411-433
• /
• 2004

The shrinkage preliminary test ridge regression estimators (SPTRRE) based on Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests for estimating the regression parameters of the multiple linear regression model with multivariate Student's t error distribution are considered in this paper. The quadratic biases and risks of the proposed estimators are compared under both null and alternative hypotheses. It is observed that there is conflict among the three estimators with respect to their risks because of certain inequalities that exist among the test statistics. In the neighborhood of the restriction, the SPTRRE based on LM test has the smallest risk followed by the estimators based on LR and W tests. However, the SPTRRE based on W test performs the best followed by the LR and LM based estimators when the parameters move away from the subspace of the restrictions. Some tables for the maximum and minimum guaranteed efficiency of the proposed estimators have been given, which allow us to determine the optimum level of significance corresponding to the optimum estimator among proposed estimators. It is evident that in the choice of the smallest significance level to yield the best estimator the SPTRRE based on Wald test dominates the other two estimators.

• Journal of Computing Science and Engineering
• /
• v.2 no.3
• /
• pp.274-300
• /
• 2008

Software testing cost can be reduced if the process of testing is automated. However, the test data generation task is still performed mostly by hand although numerous theoretical works have been proposed to automate the process of generating test data and even commercial test data generators appeared on the market. Despite prolific research reports, few attempts have been made to evaluate and characterize those techniques. Therefore, a lot of works have been proposed to automate the process of generating test data. However, there is no overall evaluation and comparison of these techniques. Evaluation and comparison of existing techniques are useful for choosing appropriate approaches for particular applications, and also provide insights into the strengths and weaknesses of current methods. This paper conducts experiments on four representative test data generation techniques and discusses the experimental results. The results of the experiments show that the genetic algorithm (GA)-based test data generation performs the best. However, there are still some weaknesses in the GA-based method. Therefore, we modify the standard GA-based method to cope with these weaknesses. The experiments are carried out to compare the standard GA-based method and two modified versions of the GA-based method.