• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1440-1443
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• 2004

In this paper, to assess and enhance the reliability of Korea High Speed Train, auxiliary power is selected and reliability analysis is carried out. The auxiliary power system is classified into subsystems and functional analysis is conducted. Reliability block diagrams are drawn. and reliability parametric analysis is performed. Analysis results show that the reliability of auxiliary power system depends on critical items. To grow the system reliability, activities have been concentrated on improvement of critical items and the results were successful.

• Journal of Applied Reliability
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• v.10 no.2
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• pp.107-122
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• 2010

Functional safety is the part of the overall safety of a system that depends on the system or equipment operating correctly in response to its inputs, including the safe management of likely operator errors, hardware failures, systematic failures, and environmental changes. One of the essential concepts of functional safety is Safety Integrity Level(SIL). It is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In this paper, each element of SIL assessment will be defined. Based on each element, specific process of SIL selection will be established by using flowchart. The flowchart provides a SIL assessment guideline for functional safety engineers. The proposed theory will be verified by applying to a oil refining plant for SIL assessment.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.255-261
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• 2007

In this paper we introduce the method, procedure and result of RAM prediction for interlocking system which is applied for AREX signaling system. For RAM prediction, we breakdown the interlocking system to the LRU level and select the LRUs of which failure can cause the service delay. The prediction of reliability is based on the Reliability Block Diagram which is the functional diagram composed of selected LRUs and finally, the availability of interlocking system is estimated from the combination of reliability and maintainability.

• Journal of the Korea Safety Management & Science
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• v.7 no.4
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• pp.219-227
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• 2005

Three general algorithms for evaluating the reliability for complex bridge system are proposed. These methods, such as Keystone, Boolean, Network algorithms are powerful and effective to derive an reliability expression for many practical complex systems. The combination approach of RBD and FTA proposed in this paper provides an effective way to evaluate the functional dependency for applications of FMEA.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.6
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• pp.267-276
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• 2021

The automotive industry and academic research have been continuously conducting research on standardization such as AUTOSAR (AUTomotive Open System ARchitecture) and ISO26262 to solve problems such as safety and efficiency caused by the complexity of electric/electronic architecture of automotive. AUTOSAR is an automotive standard software platform that has a layered structure independent of MCU (Micro Controller Unit) hardware, and improves product reliability through software modularity and reusability. And, ISO26262, an international standard for automotive functional safety and suggests a method to minimize errors in automotive ECU (Electronic Control Unit)s by defining the development process and results for the entire life cycle of automotive electrical/electronic systems. These design methods are variously applied in representative automotive safety-critical systems. However, since the functional and safety requirements are different according to the characteristics of the safety-critical system, it is essential to research the AUTOSAR functional safety design method specialized for each application domain. In this paper, a software functional safety mechanism design method using AUTOSAR is proposed, and a new failure management framework is proposed to ensure the high reliability of the product. The AUTOSAR functional safety mechanism consists of memory partitioning protection, timing monitoring protection, and end-to-end protection. The fault management framework is composed of several safety SWCs to maintain the minimum function and performance even if a fault occurs during the operation of a safety-critical system. Finally, the proposed method is applied to the Shift-by-Wire system design to prove the validity of the proposed method.

• Electronics and Telecommunications Trends
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• v.34 no.1
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• pp.123-131
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• 2019

Automotive electronics are complex and require high performance with an advanced driver assistant system (ADAS) and a functioning autonomous system. Thus, considering their complexity, the processor of the electronic control unit (ECU) requires a design that ensures high performance and reliability to ensure functional safety. This study discusses the technology used for developing a processor that can ensure functional safety of current automotive electronic systems.

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.413-427
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• 1997

This research is based on the Consumption Values Theory proposed by Sheth(1991). The purpose of this research is finding the factors related to the process of hospital choice. The expectation of six hospital outpatients 600 was analyzed by six consumption values categories: functional value, social value, emotional value, rarity value, condition value, health related values. The main results of this research is as following; 1. In the result of factor analysis 22 consumption value factors which affect the hospital preference were extracted; kindness/clearness, service speed, comfort of space, technical competence in functional values, high income/active social life, low income/blue collar unmarried/man, middle aged/big family, woman/married, introvert in social values, high-class, comfort, reliability in emotional value, newness, classiness in rarity value, social relationship, close to residence, social reputation in conditional values, priority on health, health behavior, active sense of value on health in health related values. 2. The difference of consumption values among hospital types were analyzed. The critical factors in reference for corporate hospitals newly established were kindness/clearness, service speed, convenience, classiness, comfort, and newness. University hospitals were preferred by the factors of reliability, and social reputation. In general hospital, convenience and close to residence were critical factor. 3. In logistic regression, age, marital status, education level and income as socio-demographic variables were significantly related to general hospital choice. Also service speed and close to residence were positively and high income/active social life and high class value were negatively related to general hospital choice. On university hospital choice, age and marital status, education show posive relationship whereas income showing negative relationship. Kindness/clearness, service speed, comfort of space, unmarried/man, comfortable feeling, newness and close to residence showed negative relationship with university hospital selection whereas technical competence, reliability in emotional value, classiness in rarity value, social relationship in functional values showed positive relationship. Lastly kindness/clearness, comfort of space, high income/active social life, unmarried/man, high-class, comfort and newness were positively related to corporate hospitals newly established choice in contrast to negative relationship in reliability in emotional value and classiness. In summary, we found that hospital user also choose to hospital in base of various consumption value. Further studies to investigate the hospital consumer behavior will be needed.

• Physical Therapy Rehabilitation Science
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• v.7 no.2
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• pp.61-66
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• 2018

Objective: Patellofemoral pain syndrome (PFPS) is a condition that is characterized by patellar discomfort or pain that is aggravated during certain activities such as ascending/descending stairs. The Patellofemoral Disability Index (PDI) was developed to assess the effect of pain on functional activities in individuals with PFPS. The objectives of the current study were to determine the internal consistency, test-retest reliability, and validity of this index. Design: Cross-sectional study. Methods: Forty-one subjects who had PFPS with a mean age of $28.8{\pm}5.0years$ and a mean body mass index of $25.6{\pm}4.7kg/m^2$ participated in the study. All subjects were concurrently enrolled in a clinical trial for which they were instructed to complete hamstring-resistance exercises for 4 weeks. Over the course of the intervention, they completed both the PDI and the Oswestry Disability Index (ODI) at baseline after two weeks, and after four weeks. Pearson correlation coefficient was used to assess the criterion validity. Cronbach's ${\alpha}$ was used to examine the internal consistency. Intraclass correlation coefficients with 95% confidence interval were computed to examine test-retest reliability. Results: Subjects' responses within both the PDI and the ODI yielded Pearson correlation coefficient values that were positive and highly significant (range, 0.73-0.97; p<0.001). There was a high level of internal consistency (Cronbach's ${\alpha}{\geq}0.8$), with the exception of stair climbing (Cronbach's ${\alpha}=0.65$). Intraclass correlation ranged from 0.87 to 0.92, indicating high levels of test-retest reliability. Conclusions: The PDI is a valid, reliable, and feasible method of assessing pain and functional ability in patients with PFPS.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.103-107
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• 2023

To solve the reliability problem of organic devices that are often used outdoors, multifunctional gas barriers that block reactive gases such as moisture and oxygen and reflect harmful light such as ultraviolet rays are needed. In this study, ALD nanolaminate-based optically functional n-DBR was developed to overcome the poor gas permeability of polymer substrates and protect organic devices from harmful light. n-DBR not only achieved a WVTR of 8.76 × 10^-6 g·m^-2·day^-1, but also showed a visible light transmittance of 94.3% and an ultraviolet ray blocking ability of 2.67%. In particular, n-DBR based on a nanolaminate structure maintained its permeability characteristics even in a high temperature and high humidity environment despite being used as a layer of Al₂O₃. This functional barrier Structure can not only be used as a functional encapsulation barrier for the reliability of organic devices, but can also be used as a tinting film for vehicles.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.941-946
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• 2007

In this paper, as the step to assess and enhance the reliability of Korean Tilting Train eXpress (T.T.X), Door system is selected and reliability analysis is carried out. The door system is classified into subsystems and functional block diagrams and reliability block diagrams are drawn.Expessions for evaluating the reliability are derived and Mean Kilometer between Service Failure is calculated using the trial track test results. The calculation result show reliability growth of proposed system. This paper developed RAMS to make a door system of T.T.X. (Tilting Train eXpress) with maximum operation speed of 180 km/h.