• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.73-78
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• 2003

Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.153-164
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• 2022

The purpose of this study is to investigate the relationship between psychological contract perceived by national taekwondo demonstration members and job satisfaction, organizational trust, and turnover intention. A total of 228 questionnaires were analyzed using SPSS 21.0 for members who experienced the national taekwondo demonstration team. Frequency analysis, exploratory factor analysis, reliability analysis, correlation analysis and multiple regression analysis were used. First, psychological contract had a significant effect on job satisfaction, second, psychological contract had a significant effect on organizational trust, third, psychological contract had a partial negative effect on turnover intention, fourth, job satisfaction had a significant effect on organizational trust, and fifth, job satisfaction had a partial negative effect on turnover intention.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.844-852
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• 2017

Since guided weapon is high-cost and one-shot device which is non-reusable, it requires a lot of resources to prove required accuracy as a part of reliability demonstration. Once a test for proving accuracy rate of guided missile fails, it causes an additional cost and delay of schedule. This study introduces an equation for proper sample size and plan for guided-missile accuracy rate test in order to minimize the risk of test failure. Proper sample size for the test is derived by considering the reliability growth. Furthermore, each task for accuracy rate test is defined according to the development step. Therefore, this study can contribute to reduce sample size for accuracy rate test in order to meet the reliability requirement and assure transparency in the test process.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.458-465
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• 2017

The railway signaling system, which controls the course of trains and the distance between trains, is a safety critical system of the railway system because derailment or collision of trains can occur if unsafe failure is generated by any fault. The international standards of reliability, availability, maintainability, and safety of railway applications require that the safety of functions be guaranteed in safety critical systems; system reliability and safety are quantitatively estimated and demonstrated by the failure rates of devices. The development of technology has accelerated the development of railway signaling systems. Existing devices, which have already been verified as to their safety, are applied with special user requirements to reflect the new operation scenario. It is found that the reliability and safety of the devices are different depending on individual application. Therefore, the reliability of the railway signaling system must be considered while complying with the international standards; this requires that the initial failure rate be estimated and demonstrated using fault data gathered over several years. This paper shows a method for demonstrating the initial estimated failure rate and suggests a fault data collection method and an overall process that is based on probability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.966-970
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• 2005

On the basis of the development of KSLV-1, KoDSat was designed and manufactured to demonstrate the performance of KSLV-1. KoDSat is exposed to a severe vibrational environment at launch. The structural reliability of KoDSat has to be verified using vibrational test. The structural compatibility and verification of components between analysis and test can be proved using environmental vibration test. In this paper, we review the structural characteristic of thruster control unit for a space launch vehicle and design TCU housing using mathematical model. In order to verify the structural compatibility and reliability, half-sine shock, random and sing sweep vibration test was performed. Especially, sing sweep vibration test result is compared with analysis result and mathematical model is verified.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.51-54
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• 2000

We are concerned with processing methods of the measurement values of sensors in the control system. When some faults happen to sensor components, the measurement value of sensors cause the malfunction of the plant. So it is necessary to detect and reduce the influence of faults to control with reliability for the overall system. The sensor status must be always good for best demonstration of the controller performance. A self-validating sensor detects the sensor state from the measurement value, reconstruct a soft sensor and can improve reliability of the sensor. If sensor faults, the sensor is detected and reconstructed with the best estimate from its correlation to other sensors and historical data. It is applied to the control of a flexible link system with the sensor fault problems in the light sensor module for position to show the applicability. In this paper, we propose a digital controller which reduces deflection of the moving set-point by reconstructing output of a sensor when the sensor fault is detected.

• Structural Engineering and Mechanics
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• v.28 no.4
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• pp.479-489
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• 2008

In this study an approximate method based on the continuum approach and transfer matrix method for static and dynamic analyses of stiffened multi-bay coupled shear walls is presented. In this method the whole structure is idealized as a sandwich beam. Initially the differential equation of this equivalent sandwich beam is written then shape functions for each storey is obtained by the solution of differential equations. By using boundary conditions and storey transfer matrices which are obtained by these shape functions, system modes and periods can be calculated. Reliability of the study is shown with a few examples. A computer program has been developed in MATLAB and numerical samples have been solved for demonstration of the reliability of this method. The results of the samples show the agreement between the present method and the other methods given in literature.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.89-96
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• 2007

The amount of home deliveries are increasing day by day owing to the increment of the on-line market. This environment brings along generating many delivery companies and keen competition with each other in its customer hold Therefore, this study aims at the development of a shortest delivery route search demonstration system using Ant Algorithm. The developed system reduces the time consumption significantly in search of delivery path and time of the products for the novice delivery driver as well as experienced driver. Ultimately, the developed system will give the customer reliability and satisfaction, knowing a delivery route in advance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.71-74
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• 2010

Using the technology demonstration model of 75-tonf-class combustor which is expected to be used to the rocket engine of a korean space launch vehicle, 2 times of firing tests were carried out. Firing tests were done at 50% of the nominal flow rate because of incapability of the test facility and limit of the test bed strength. Through the low pressure firing tests of 75-tonf-class channel cooling thrust chamber, reliability and stability at the ignition and combustion phases were confirmed. Additionally it was foreseen that the 75-tonf-class thrust chamber would satisfy the performance requirements.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.803-807
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• 2008

The ubiquitous middleware configurated an aggregation of the various services. The services are made in different languages and the various services that are dynamically changing environment are carried out in collaboration service. The ubiquitous system that services in the these environment is required appropriate response to real-time system and reliability. In this paper, we suggest the monitoring agent that a monitoring system added or removed the services in real-time is made continuous monitoring in run-time environment and guaranteed performance and reliability of a application by maximally reducing overhead that combined with applications is occurred. The suggested scheme shows the demonstration to fit the scenario situation and verifies function and performance of monitoring about the service applications through the experiment.