• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.6
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• pp.7-11
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• 2002

This paper estimates defect and outbreak probabilities of each individual component from some subset of masked data where the exact component causing system failure might be unknown. A system consists of k components that fails whenever there is a defect in at least one of the components. Due to cost and time constraints it is not feasible to learn exactly which components are defective. Because, test procedures ascertain that the defective components belong to some subset of the k components. This phenomenon is termed masking. We describe a, b, c type in which a sample of masked subsets is subjected to intensive failure analysis. This recorded data of a, b, c type enables maximum likelihood estimation of defect probability of each individual component and leads to outbreak of the defective components in future masked failures.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.230-237
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• 2001

For the structural integrity of large and complex structures such as railway vehicle, the in-field diagnosis of mechanical properties of the structures is needed, and especially, the mechanical characteristics of the weldment must be carefully evaluated. But, conventional standard testing methods having destructive procedures are not applicable to in-field assessment of mechanical property variations within weldment because they needs the limitations of specimen size and geometry. In this paper, to overcome this problems, the advanced indentation technique (AIS) is introduced for simple and non-destructive/in-field testing of weldment of industrial structures. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. First of all, flow properties such as yield strength, tensile strength and work hardening index can be evaluated through the analysis of the deformation behavior beneath the spherical indenter. Additionally, case studies of advanced indentation techniques are introduced.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.81-88
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• 2006

The purpose of this study is to verify the dimensions of service quality of Korea Train Express(KTX) and to compare the service quality of KTX with that of general train. The researcher consisted of initial 32 items representing eight-dimension and analyzed the final quality dimensions of KTX. The collected data of passenger of 226 was analyzed by statistical procedures such as the iterative sequence of computing Cronbach's a, corrected item-to total correlations, and factor analyses. Through the repeated statistical process to puritY the items, a final set of 26 items representing six district dimensions; tangibles, timely responsiveness, empathy, comfort, information access and safety. The Results of independent samples t-test showed that the mean scores of all the service quality dimensions of KTX except for comfort were higher than those of general train. This finding will provide the more appropriate instrument to measure the KTX service quality as well as to improve the passengers' perception of the service quality.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.99-106
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• 1996

Estimation and removal procedures for baseline drift have been developed using linear, cubic spline, and bilineared transformed high pass filter. Linear and cubic spline interpolation with the PQ and TP segmens, which are considered to be isoelectric, as fiducial points ahve been estimated respectively. For a quantitative validation of the estimation procedure, 4 ECGs with arfificial baseline drift were constructed and analyzed by mean square error calculations and amplitude histograms. Also real ECGs were analyzed in a test set of the CSE data set 3 and set 4. Baseline drift detecton rule were designed and new method for the decision of fiducial point were constructed to avoid distorting as the case of premature ventricular or atrial contraction. From these comparison, proposed cubic spline method with PQ and TP segment (CS_PQ & TP) emerged as the most efficient method.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.145-156
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• 2009

Large diameter bored pile was selected as the foundation type for Taipei 101. The pile construction method and specific construction procedures were determined based on the results of trial installation and pile load tests. The baseline for foundation design was established using the friction versus depth characteristics of each ground layer obtained from the pile load tests. As the ground profile and depth to the top of rock formation varied significantly on this site, the pile length, bearing capacity and settlement for single pile were analyzed using the information interpreted from adjacent boreholes. The post grouting at pile tip was mandatory for pile construction. Nevertheless, it was treated as a measure reducing the influence of construction uncertainties and providing extra safety for the foundation system.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2017-2019
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• 2000

In recent the XLPE cable has been applied more widely because of its advantages, such as the low-cost and simple installation. For a prefabricated joint, its working time is short, its jointing procedures are simple, and its quality control is easy. Electrical performance targets of our developed 132kV cable accessories has been approved through the type test in accordance with IEC publication 840. This paper describes the developmental effort in terms of the design, structure and results of performance verification tests for 132kV XLPE cable system.

• Progress in Superconductivity and Cryogenics
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• v.13 no.4
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• pp.14-17
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• 2011

The evaluation of the electromechanical properties of HTS CC tapes is one of the foremost procedures to be done to ensure the applicability of superconducting wires to electric devices. A precise measurement of the stress and strain is important in deriving the mechanical properties under operating environment. Up to now, there is no standard test method yet for the electromechanical property evaluation of HTS tapes under self field and external magnetic field although there are already reports on the different devices used to evaluate these properties. Strain can be measured by adopting a strain gauge or a high resolution double extensometer. In this study, strain effect on $I_c$ in HTS CC tapes under magnetic fields was evaluated. Comparison of advantages and setback of strain measuring devices were discussed. In addition, a dual strain measurement system using both the SG and extensometer may be practical to lessen the burden in case one of the measuring devices does not work well.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.195-198
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• 2000

Microstrip antenna for SAR applications is designed with microwave composite laminates and Nomex honeycomb cores, which becomes an aircraft's structural panel. This study demonstrated fabrication, design procedures and structural and electrical performances of complex antenna system presented. For validating structural rigidity, 3-point bending test is performed, and simulation results for the complex antenna array are compared with measurements for its electrical performance. The results show that this antenna system can be applied in dual polarized synthetic aperture radar and has a good flexural stiffness with comparison of previous sandwich constructions.

• Structural Engineering and Mechanics
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• v.6 no.4
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• pp.439-455
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• 1998

A three-dimensional static nonlinear finite element analysis was performed on the NUPEC large-scale flanged shear wall, which was the subject of an international study program. Details of the constitutive models and analysis procedures used are provided, and the results of the analysis are presented and discussed. The analytical results are compared to the experimentally observed behaviour, and reasonable correlation is observed. Deficiencies in the modelling are identified. In addition, a parametric study is undertaken to investigate factors and mechanisms influencing both the observed behaviour and the calculated response. Finally, a cyclic load analysis of the wall is described and discussed. The paper serves to point out aspects in modelling that are critical to both producing realistic results, and correctly interpreting those results.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1709-1714
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• 2004

Pressurization system of a 50m unmanned airship was manufactured according to the detailed design. In this paper. the whole procedures including system design. simulation and fabrication were described. The fabricated part were ground tested to check compliances with design requirements. Ground tests include operational tests, leakage tests, endurace tests and low temperature environmental tests. Results shows pressurization system of a 50m unmanned airship meets design requirements. Currently. pressurization system is installed to the KARI airship, Via 50m and performance verification through the flight tests are being conducted.