• Journal of Applied Reliability
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• v.18 no.3
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• pp.213-219
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• 2018

Purpose: Satisfying the environmental regulations, the automobile manufacturer should install urea tank, which is a key component of the urea system. However, due to the limitations of existing layouts, it may be mounted which is disadvantageous to vibration and shock resulting in durability robust. analyze the factors affecting the durability life of urea tank and the vibration characteristics through RLDA. In this study, clarify the limit of the current practice test method of urea tank and analyze the possibility of the new vibration test method in the system unit reflecting the characteristics of actual use condition. Methods: Analyzing the factors affecting the durability life of urea tank and the vibration characteristics through PSD & FDS of RLDA that actual vehicle driving data on durability test road. Results: The limit of the uniform width/single frequency test method of urea tank is clarifed and the positive prospects of the new test method are discovered. Conclusion: The vibration durability test with PSD method in system unit effectively reflects the magnitude and frequency characteristics of field vibration.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.9-16
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• 2018

Recently, as various IP set-top boxes based on Android OS have been widely used in general households and public facilities, complaints about services and set-top boxes have continued to increase as much as other smart devices. In order to reduce this problem, the manufacturer performs the testing work before the product is commercialized. However, the testing can reduce potential defects in the product, but it can not prove that the product is free of defects. Therefore, the quality of the product can vary depending on how effective testing techniques are introduced. In this paper, we propose a new exploratory testing method that minimizes test case creation time and makes it easier to plan and execute test while simultaneously learning how to run the product under test. Using the first proposed method, the test time is reduced by about 16.7 hours and the defect detection rate is 25.4% higher than the formal specification-based testing method. Informally, the test time was shortened by about 4.7 hours and the defect detection rate was 13% higher than the informal experience-based testing method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.217-224
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• 2010

The purity methods to determine LOD/LOQ using standard deviation of the residual, intercept and blank by IUPAC and ACS describe many of the pitfalls and pose significant challenges to analytical chemists. Therefore, the aim of this study is the development of the simple, easy, convenient and statistically significant method to determine LOD in quantitative analysis of organic solvents by GC. The new approaching method by linearization in the given concentration range used coefficient of variation ; ${\sigma}_{n-1}$/S(standard deviation, ${\sigma}_{n-1}$ and average, S) of sensitivity(Response/concentration). The comparison of results among the purity methods(IUPAC and ACS) and the linearization have been fulfilled the F-test for standard deviations and t-test for LOD range values. The results of F-test and t-test are satisfied within 95 % confidence level, respectably. The LOD values determined by the new procedure are n-Hexane 0.0116 mg/$m^3$, Toluene 0.0807 mg/$m^3$, and o-Xylene 0.0494 mg/$m^3$. Because the standard deviation of the residual, intercept and blank and the slope of calibration curve are not calculated and the new approaching method use the coefficient of variation of sensitivity by linearization, this new method is simple, easy, convenient and statistically significant. In future, many chemical analysts will expect to applicate and routinely use this method in the all quantitative analysis.

• ETRI Journal
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• v.23 no.2
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• pp.77-84
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• 2001

The detection of open defects in CMOS SRAM has been a time consuming process. This paper proposes a new dynamic power supply current testing method to detect open defects in CMOS SRAM cells. By monitoring a dynamic current pulse during a transition write operation or a read operation, open defects can be detected. In order to measure the dynamic power supply current pulse, a current monitoring circuit with low hardware overhead is developed. Using the sensor, the new testing method does not require any additional test sequence. The results show that the new test method is very efficient compared with other testing methods. Therefore, the new testing method is very attractive.

• Tunnel and Underground Space
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• v.4 no.3
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• pp.237-249
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• 1994

A new type of cut method, called SK-cut, was developed in order to overcome the shortcomings of the conventional V-cut and Burn-cut blasting methods. Total 190 times of test blasts were performed for the evaluation of the efficiency of new blasting method. V-cut, Burn cut and SK-cut were compared by applying them to the excavation of main gallery and construction tunnel of underground oil storage cavern. Test results showed that excavation efficiency of the new method was increased by 5.9~9.8% and that specific charge was reduced to 71~92%.

• Journal of Ship and Ocean Technology
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• v.3 no.3
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• pp.25-44
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• 1999

Estimation efficiencies according to different sea trial are investigated in connection with sensitivity analysis, and new trial method is proposed which can improve the estimation efficiency of hydrodynamic derivatives. MMG Equation with Kijima's formula is used for simulation. Extended Kalman Filter is chosen for estimation technique and hydrodynamic derivatives of interest is limited to 12 of those in sway and yaw equations. Esso Osaka is selected for the test ship. Sensitivity analysis and estimation results based on conventional trials show that a more sensitive derivative gives more efficient estimation result. Sensitivities of nonlinear derivatives become pronounced in the trial where steady condition lasts longer such as turning test, while sensitivities of linear derivatives gas a larger values in the trial where unsteady condition lasts longer such as 10deg-10deg zigzag test. Consequently, in new method , named S-type trial, steady and unsteady condition are combined appropriately to increase sensitivities. Linear derivatives are estimated better in S-type trial and the estimation of nonlinear derivatives is improved to extent.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.3
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• pp.46-54
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• 1984

A new controller tuning method for solving problems that cannot be applicable to the processes with large time delay by Yuwana-Seborg method is presented. The new method is based on a single experimental test, a step change in the controller set point. Simulation results show that the new method can be not only well applicable to systems including large delay processes but also is superior to Ziegler-Nichols method or Cohen-Coon method in many respects despite unanticipated load disturbances that may occur during the experimental test.

• International Journal of Fluid Machinery and Systems
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• v.8 no.4
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• pp.221-229
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• 2015

For efficient design process of regenerative blower, the present study provides new generalized pressure and leakage flow loss models, which can be used in the performance analysis method of regenerative blower. The present performance analysis on designed blower is made by incorporating momentum exchange theory between impellers and side channel with mean line analysis method, and its pressure loss and leakage flow models are generalized from the related fluid mechanics correlations which can be expressed in terms of blower design variables. The present performance analysis method is applied to four existing models for verifying its prediction accuracy, and the prediction and the test results agreed well within a few percentage of relative error. Furthermore, the present performance analysis method is also applied in developing a new blower used for fuel cell application, and the newly designed blower is manufactured and tested through chamber-type test facility. The performance prediction by the present method agreed well with the test result and also with the CFD simulation results. From the comparison results, the present performance analysis method is shown to be suitable for the actual design practice of regenerative blower.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.13-19
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• 2010

A design method of railway wheel profile with objective function of equivalent conicity considering wheel dimension constraint, two points contact problem between wheel and rail was proposed. New design method shows good results. New wheel profile generated from optimization process shows better dynamic performance compared with initial profile as the purpose of wheel profile design. And to verify the design method with testing the stability of new wheel profile, we conducted a critical speed test for new wheel profile using scale model applied scaling method of railway vehicle dynamics. The result of critical speed test show good agreement with that of numerical analysis. From the above results, it is seen that the design method with objective function of equivalent conicity is feasible and it could be applied to design new wheel profile efficiently.

• Journal of the Korean Data and Information Science Society
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• v.16 no.1
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• pp.137-144
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• 2005

In $I{\times}J$ incomplete contingency tables, the test of independence proposed by Chen and Fienberg(1974) uses $I{\times}J-1$ instead of (I-1)(J-1) degrees of freedom without providing much of an increase in the value of the test statistic. For these reasons, Chen and Fienberg tests are expected to have less power. New Wald test statistic related to the part of Chen and Fienberg test statistic is proposed using delta method. These two tests are compared through Monte Carlo studies.