• Communications for Statistical Applications and Methods
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• v.11 no.3
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• pp.475-484
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• 2004

This paper consider the testing problem of grouped heteroscedasticity in the linear regression model. We provide the Lagrange Multiplier(LM), Wald, Likelihood Ratio (LR) test statistis for testing of grouped heteroscedasticity. Monte Carlo experiments are conducted to study the performance of these tests.

• Structural Engineering and Mechanics
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• v.6 no.5
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• pp.571-582
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• 1998

Testing of steel roof purlins is usually performed on full scale models in large vacuum test rigs. To undertake a comparison between web cleat connected purlins and flange bolted purlins a series of tests were performed on a 1:4 small scale model vacuum test rig. Various modelling issues need to be addressed to ensure reasonable comparison with actual constructed roof framing methods but still be suitable for an economical comparison between the connection methods. Model test results were supported by, and found to be in reasonable agreement with, deflection predictions from computer models based on finite element methods. This paper discusses the testing methods adopted and the value of small scale model testing programs as a means of obtaining comparisons between framing options.

• Journal of Korean Society for Quality Management
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• v.34 no.3
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• pp.73-78
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• 2006

In this paper, we propose a software reliability growth model based on the testing domain in the software system, which is isolated by the executed test cases in software testing. In particular, our model assumes an imperfect debugging environment in which new faults are introduced in the fault-correction process, and is formulated as a nonhomogeneous Poisson process(NHPP). Further, it is applied to fault-detection data, the results of software reliability assessment are shown, and comparison of goodness-of-fit with the existing software reliability growth model is performed.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1319-1327
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• 2001

The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed 1:1 scale. The model experiments were executed at a lower pressure than that in a real gas turbine. Combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure and NOx emission were measured at partial and full loads for both model and on-site testing. The comparison of these items in the stand and field test results led to has the development of a method of calculation and the improvement of gas turbine combustors.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.511-519
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• 2010

This paper presents the modeling and validation of a pile-driver breech fatigue testing system model to replicate actual high pressure in a large caliber gun barrel. A hysteresis damping function was incorporated in the nonlinear impact force model. Test of real pile-driver breech fatigue testing system had been performed for model validation. Comparison of the experimental result and model simulation during impact were made. Numerical studies were performed to evaluate how the actual chamber pressure pattern in the live firing of gun barrel was affected by parameters' variation. Some of the parameters simulated included input velocity, damping coefficient and stiffness. As a result, a variety of actual chamber pressure pattern could be reproduced and controlled through current simulation model.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.835-842
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• 2001

We propose a software-reliability growth model incoporating the amount of testing effort expended during the software testing phase. The time-dependent behavior of testing effort expenditures is described by a Weibull curve. Assuming that the error detection rate to the amount of testing effort spent during the testing phase is proportional to the current error content, a software-reliability growth model is formulated by a nonhomogeneous Poisson process. Using this model the method of data analysis for software reliability measurement is developed. After defining a software reliability, we discuss the relations between testing time and reliability and between duration following failure fixing and reliability are studied in this paper. The release time making the testing cost to be minimum is determined through studying the cost for each condition. Also, the release time is determined depending on the conditions of the specified reliability. The optimum release time is determined by simultaneously studying optimum release time issue that determines both the cost related time and the specified reliability related time.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.611-614
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• 2004

As information telecommunication industry develops and systems get integrated gradually, the importance of embedded software is growing significantly. On the contrary, the reliability of embedded software has worsened. Accordingly, testing of software is an essential part in designing and building up embedded system and the volume of testing required is immense. This paper elaborates on design and testing model for complex embedded software, providing guidelines to collect requirements for complex embedded software.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.313-321
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• 2006

This paper describes the overvoltage obtained by surge behavior analysis in testing underground distribution systems. Model systems consist of overhead distribution line and underground cable. Such model system considered various characteristics of actual distribution systems will be soon constructed at testing yard. Simulation is carried out under various states such as cable kinds, cable length, lightning wave and time, and branch circuits. Model is established by EMTP/ATPDraw. Line Constants are calculated by ATP_LCC. When the direct lightning surge strikes on conductor of overhead line, the overvoltage is calculated using EMTP/ATPDraw in many cases. Simulation results will be compared with real testing results at testing yard in the near future. The compared results will be used to establish protection methods in actual underground distribution systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.203-206
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• 2006

In this study, the method of designing the flexible wing model which will be used for wind tunnel testing of gust response alleviation system was presented. The design concept proposed herein was validated by performing the modal testing of the flexible wing model manufactured for demonstration purpose. In addition, the study on the gust response alleviation using flexible wing control surface was performed. For this purpose, optimal control with output feedback was adopted for designing the control surface controller, and the effects of gust response alleviation was validated by performing the numerical simulation for the representative flexible wing model. The methods proposed and validated in this study can be applied for wind tunnel testing of the flexible wing for gust response alleviation.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.408-418
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• 1998

This paper presents the implementation of comparator which is self-testing with respect to the faults caused by any single physical defect likely to occur in NMOS and CMOS integrated circuit. The goal is to use it for the fault-tolerant system. First, a new fault model for PLA(Programmable Logic Array) is presented. This model reflects several physical defects in VLSI circuits. It focuses on the designs based on PLA because VLSI chips are far too complex to allow detailed analysis of all the possible physical defects that can occur and of the effects on the operation of the circuit. Second, this paper shows that these design, which has been implemented with 2 level AND-ORor NOR-NOR circuit, are optimal in term of size. And it also presents a formal proof that a comparator implemented using NOR-NOR PLA, based on these design, is sol f-testing with respect to most single faults in the presented fault model. Finally, it discusses the application of the self-testing comparator as a building block for the implementation of the fault-tolerant system.