• Steel and Composite Structures
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• 제19권6호
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• pp.1369-1379
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• 2015

In this study, a progressive damage modeling is developed to predict functional failure pressure of GRP pipes subjected to internal hydrostatic pressure. The modeling procedure predicts both first-ply failure pressure and functional failure pressure associated with the weepage phenomenon. The modeling procedure is validated using experimental observations. The random parameters attributed to the filament winding production process are identified. Consequently, stochastic simulation is conducted to investigate the influence of induced inconsistencies on the functional failure pressures of GRP pipes. The obtained results are compared to realize the degree to which random parameters affect the performance of the pipe in operation.

• 대한간호학회지
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• 제36권5호
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• pp.853-862
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• 2006

Purpose: The purpose of this study was to identify the factors that influence the functional status of patients with heart failure. Method: A descriptive, correlational study design was used. The participants in this study were 260 patients with heart failure who were admitted at Y University and U University in Seoul, Korea. Between September 2005 and December 2005 data was collected by an interview using a questionnaire and from medical records. The Functional status was measured with KASI. Physical factors (dyspnea, ankle edema, chest pain, fatigue, and sleep dysfunction), psychological factors (anxiety and depression), and situational factors (self-management compliance and family support) were examined. Result: In general, the functional status, anxiety, depression, self-management compliance, and family support was relatively not good. The level of fatigue was highest and the level of ankle edema was lowest for physical symptom experiences. In regression analysis, functional status was significantly influenced by dyspnea(23%), age(13%), monthly income(7%), fatigue(3%), ankle edema(2%), depression(1%), and length of stay in the hospital(1%). These factors explained 50% of the variables in the functional status. Conclusion: These results suggest that psycho-physiological symptoms management should be a focus to improve the functional status in patients with heart failure.

• 성인간호학회지
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• 제27권2호
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• pp.242-250
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• 2015

Purpose: To evaluate heart failure knowledge and adherence to self-care behaviors, and to identify factors affecting adherence to self-care behaviors among Korean patients with heart failure. Methods: Correlational research using the European Heart Failure Self-care Behavior Scale, the Duke Activity Status Index, the Dutch Heart Failure Knowledge Scale, the New York Heart Association Functional Classification, and the Medical Outcomes Study Social Support Survey was conducted. A total of 280 outpatients with heart failure responded to the five questionnaires. Results: The mean scores for self-care adherence and heart failure knowledge were $31.98{\pm}6.81$ and $8.78{\pm}2.53$, respectively, indicating lower adherence and knowledge than those previously reported. Subjects with lower functional status, more social supports, and greater knowledge of heart failure are more likely to adhere to prescribed regimens. Conclusion: Nurses should focus on patient education and support to improve their adherence to self-care behaviors.

• 한국통신학회논문지
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• 제29권4A호
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• pp.399-414
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• 2004

In this paper, an evolution of software reliability engineering in a large-scale software project is summarized. The considered software consists of many components, called functional blocks in software of switching system. These functional blocks are served as the unit of coding and test, and the software is continuously updated by adding new functional blocks. We are mainly concerned with the analysis of the effects of these software components in software reliability and reliability evolution. We analyze the static characteristics of the software related to software reliability using collected failure data during system test. We also discussed a pattern which represents a local and global growth of the software reliability as version evolves. To find the pattern of system software, we apply the S-shaped model to a collection of failure data sets of each evolutionary version and the Goel-Okumoto(G-O) model to a grouped overall failure data set. We expect this pattern analysis will be helpful to plan and manage necessary human/resources fur a new similar software project which is developed under the same developing circumstances by estimating the total software failures with respect to its size and time.

• 대한안전경영과학회지
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• 제15권4호
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• pp.161-169
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• 2013

Due to the recent advances in technology, the systems are becoming more demanding in terms of functionality and implementation complexity. Therefore, when system failures are involved in such complex systems, the effects of the related safety issues can also be more serious, thereby causing in the worst case irrecoverable hazards on both human being and properties. This fact can be witnessed in the recent rail systems accidents. In general, the accidents can be attributed to the systematic failure or the random failure. The latter is due to the aging or unsatisfied quality of the parts used in implementation or some unexpected external cause that would otherwise result in accidents whereas the former is usually related to incomplete systems design. As the systems are becoming more complex, so are the systematic failures. The objective of the paper is to study an approach to solving the systematic failure. To do so, at first the system design process is augmented by the functional safety activities that are suggested in the standard IEC 61508. Analyzing the artifacts of the integrated process yields the traceability, which satisfies the requirements for reduction of systematic failure as provided in ISO 26262. In order to reduce systematic failure, the results are utilized in the conceptual design stage of systems development in which systems requirements are generated and functional architecture is developed.

• Journal of Yeungnam Medical Science
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• 제1권1호
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• pp.13-23
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• 1984

Acute renal failure refers to a rapid reduction in renal function that usually occurs in an individual with no known previous renal disease. Development of a complication of acue renal failure in critically ill surgical patients is not unusual, and it causes high morbidity and mortality. Acute renal failure can be divided as Pre-renal (functional), Renal (organic), and Post-renal (obstructive) azotemia according to their etiologies. Early recognition and proper correction of pre-renal conditions are utter most important to prevent an organic damage of kidney. These measures include correction of dehydration, treatment of sepsis, and institution of shock therapy. Prolonged exposure to ischemia or nephrotoxin may lead a kidney to permanent parenchymal damage. A differential diagnosis between functional and organic acute renal failure may not be simple in many clinical settings. Renal functional parameters, such as $FENa^+$ or renal failure index, are may be of help in these situations for the differential diagnosis. Provocative test utilyzing mannitol, loop diuretics and renovascular dilators after restoration of renal circulation will give further benefits for diagnosis or for prevention of functional failure from leading to organic renal failure. Converting enzyme blocker, dopamine, calcium channel blocker, and propranolol are also reported to have some degree of renal protection from bioenergetic renal insults. Once diagnosis of acute tubular necrosis has been made, all measures should be utilized to maintain the patient until renal tubular regeneration occurs. Careful regulation of fluid, electrolyte, and acid-base balance is primary goal. Hyperkalemia over 6.5 mEq/l is a medical emergency and it should be corrected immediately. Various dosing schedules for medicines excreting through kidney have been suggested but none was proved safe and accurate. Therefore blood level of specific medicines better be checked before each dose, especially digoxin and Aminoglycosides. Indication for application of ultrafiltration hemofilter or dialysis may be made by individual base.

• 대한화학회지
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• 제63권1호
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• pp.24-28
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• 2019

In this work, we discuss where the failure of Kohn-Sham Density Functional Theory (DFT) occurs in weak interactions. We have adopted density-corrected density functional calculations and dispersion correction separately to find out whether the failure is due to density-driven error or functional error. The results of Benzene Ar complex, one of the most common examples of van der Waals interactions, show that DFT calculations of van der Waals interaction suffer from functional error, rather than density-driven error. In addition, errors in DFT calculations of the S22 dataset, which contains small to relatively large (30 atoms) complexes with non-covalent interactions, are governed by functional errors.

• 한국해안·해양공학회논문집
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• 제22권1호
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• pp.18-24
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• 2010

본 연구에서는 지진해일에 의한 원자력발전소의 확률론적 안전성 평가를 위하여 취약도 함수 도출에 관한 연구를 수행하였다. 이를 위하여 기존의 지진 등을 대상으로 한 외부사건에 대한 확률론적 안전성 평가방법을 분석하여 원자력발전소를 대상으로 한 지진해일의 취약도 평가방법을 제시하였으며 주요 설비 및 구조물에 대한 파괴모드 및 파괴기준을 검토하였다. 최종적으로 원자력발전소의 소외 변압기를 대상으로 지진해일 취약도 평가를 수행하였다. 결과적으로 원자력발전소의 소외변압기는 지진해일 발생시 동수압에 의한 전도와 미끄러짐과 같은 구조적인 손상 보다는 범람에 의한 기능적 손상에 의해서 파손될 가능성이 높은 것으로 평가되었다.

• 산업공학
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• 제25권4호
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• pp.376-381
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• 2012

As the number, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., safety integrity levels, SILs) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508 since SILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This article presents a case study on the assessment of SILs applying failure modes, effects and diagnostic analysis (FMEDA) from which failure rates may be derived for each important failure category by combining a standard FMEA with online diagnostic techniques.

• 한국철도학회논문집
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• 제8권2호
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• pp.170-175
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• 2005

This study presents a prediction of a failure rate in a safety required system that consists of a embedded control system, requiring a satisfaction of a quantitative safety requirement. International Standards are employed to achieve a regular procedures in the whole life cycle of a system, for the purpose of a prediction and a evaluation of a fault that might be able to be happened in a system. This International Standards uses SIL (Safety Integrity Level) to evaluate a safety level of a system. SIL is divided into 4 levels, from level 1 to level 4, and each level has functional failure rate and dangerous failure rate of a system. In this paper we describe the conventional method to predict the dangerous failure rate and propose a method using hazard analysis to predict the dangerous failure rate. The conventional method and the technique using hazard analysis to predict the dangerous failure rate are made a comparison through the control modules of the interlocking system in KTX. The proposed method verify better effectiveness for the prediction of the dangerous failure rate than that of the conventional method.