• Journal of the Korean Society for Aviation and Aeronautics
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• v.11 no.2
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• pp.23-32
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• 2003

In this paper, the design data of an aircraft generator have been reviewed to evaluate the compliance with the airworthiness standards, and the technical procedure to ensure safety and reliability of an alternate-current generator by the tests and computations have been developed.

• Geotechnical Engineering
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• v.4 no.2
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• pp.5-14
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• 1988

A probabilistic model for the progressive failure in a homogeneous soil slope consisting of strain-softening material is presented. The local safety margin of any slice above failure surface is assumed to follow a normal distribution. Uncertainties of the shear strength along potential failure surface are expressed by one-dimensional random field models. In this paper, only the case where failure initiates at toe and propagates up to the crest is considerd. The joint distribution of the safety margin of any two adjacent slices above the failure surface is assumed to be bivariate normal. The overall probability of the sliding failure is expressed as a product of probabilities of a series of conditional el.eats. Finally, the developed procedure has been applied in a case study to yield the reliability of a cut slope.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.819-825
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• 2004

The maintenance CALS system for car of urban transit is a part of standardization and development of urban transit system, and We have been performed the establishment of maintenance CALS system from 2001 to 2005. These 2D and 3D configuration management system are utilized in a variety of CALS system for user's convenience and safety in maintenance. In this paper, the 2D and 3D configuration system will be discussed for necessity and possibility. This system include RAMS(reliability, availability, maintainability and safety) of the vehicles shall be enhanced in the future.

• 시스템엔지니어링워크숍
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• s.1
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• pp.65-68
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• 2003

The air separation plants in the POSCO's Gwangyang Steel Works require high standard on quality as well as reliability as they have to continuously supply essential utility gases as oxygen, nitrogen and argon. And the plants are in the category of high pressure gas systems by the regulatory guidelines, which signifies that they have to maintain utmost level of safety. As an effort to systematically understand and calculate the risk potentials in the air separation plants, risk assessments have been performed on a phased approach: qualitative and followed by quantitative POSCO has chosen to use hazard and operability study and fault tree analysis to satisfy the requirement. As a result, the risk assessment team has identified number of safety and operability related findings. With importance of each and ever findings calculated, a priority list for what/when to do for them could have been presented on a balance fashion.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.999-1016
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• 2015

In this paper, we introduce a new method for assembly of shipbuilding blocks at sea and present its feasibility focusing on structural safety. The core concept of this method is to assemble ship building blocks by use of bolting, gluing and welding techniques at sea without dock facilities. Due to its independence of dock facilities, shipyard construction capability could be increased considerably by the proposed method. To show the structural safety of this method, a bulk carrier and an oil tanker were employed, and we investigated the structural behavior of those ships to which the new block assembly method was applied. The ship hull models attached with connective parts are analyzed in detail through finite element analyses, and the cargo capacity of the bulk carrier is briefly discussed as well. The results of these studies show the potential for applying this new block assembly method to practical shipbuilding.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.238-243
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• 2002

The maintenance CALS system for car of urban transit is a part of standardization and development of urban transit system, and We have been performed the establishment of maintenance CALS system from 2001 to 2005. These 2D and 3D configuration management system are utilized in a variety of CALS system for user's convenience and safety in maintenance. In this paper, the 2D and 3D configuration system will be discussed for necessity and possibility. This system include RAMS(reliability, availability, maintainability and safety) of the vehicles shall be enhanced in the future.

• Smart Structures and Systems
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• v.22 no.6
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• pp.699-709
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• 2018

With increasing traffic volumes and rising vehicle traffic, especially in cities, the number of pedestrian bridges has also increased significantly. Like all other structures, pedestrian bridges also suffer damage. In order to increase the safety of pedestrians, it is necessary to identify existing damage and to repair them to ensure the safety of the bridge structures. Owing to the shortcomings of local methods in identifying damage and in order to enhance the reliability of detection and identification of structural faults, signal methods have seen significant development in recent years. In this research, a new methodology, based on cone-shaped kernel distribution with a new damage index, has been used for damage detection in pedestrian truss bridges. To evaluate the proposed method, the numerical models of the Warren Type steel truss and the Arregar steel footbridge were used. Based on the results, the proposed method and damage index identified the damage and determined its location with a high degree of precision. Given the ease of use, the proposed method can be used to identify faults in pedestrian bridges.

• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.27-39
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• 2006

Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.57-64
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• 1989

This study presents a reliability-based optimum design of reinforced concrete frames, in which the AFOSM and SOSM methods are applied for the evaluation of the failure probabilities, and the sequential linear programming method is used as a practical approach to the system optimization. One-story two-bay reinforced concrete frame is chosen for the numerical illustration of the proposed reliability-based optimum design. As a result, it is found that the proposed procedure for the reliability-based optimization of RC frames could provide the accurate estimation of the optimal level of safety, and appears applicable to real structures with reasonable complexity. It is shown in the paper that the probability distributions of the basic random variables and the uncertainties of the applied loadings and material strengths may have great effect on the optimum design, but the AFOSM and SOSM methods do not show significant discrepancy in the optimum design results, but the former appears more realistic and time saving than the latter for this specific study.

• Journal of Korean Physical Therapy Science
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• v.29 no.1
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• pp.30-40
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• 2022

Background: This study analyzed the reliability of smart guides for gait analysis in patients with stroke. Design: Cross-sectional study. Methods: The participants of the study were 30 patients with stroke who could walk more than 10 m and had an MMSE-K test score of ≥24. Prior to the experiment, the subjects or their guardians entered their demographic characteristics including gender, age, height, weight into the prepared computer. The experiment was conducted in a quiet, comfortable, and independent location, and the patient was reminded of the equipment description, precautions, and safety rules for walking. A smart insole was inserted into the shoes of the patients and the shoes were put on before the patients walked three times on the 5-m gait analysis system mat installed in the laboratory. Results: The reliability of the equipment was compared with that of the gait analysis system, and the results of this study are as follows: among the gait analysis items, velocity had an ICC=0.982, the cadence had an ICC=0.905, the swing phase on the side of the gait cycle had an ICC=0.893, the swing phase on the side of the gait had an ICC=0.839, that on the non-affected side had an ICC=0.939, single support on the affected side had an ICC=0.812, and support on the non-affected side had an ICC=0.767. Conclusion: The results of this study indicate no statistical difference between the smart insole and the gait analysis system. Therefore, it is believed that real-time gait analysis through smart insole measurement could help patients in rehabilitation.