• Title/Summary/Keyword: functional failure

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A Study on the Performance Simulator of Digital Protective Relay (디지탈 보호계전기 성능 시뮬레이터에 관한 연구)

  • Choi, Sang-Bong;Moon, Young-Whan
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.152-155
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    • 1993
  • Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.

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Traumatic Ventricular Septal Defect Secondary to Nonpenetrating Chest Trauma -A Case Report- (비관통성 외상에 의한 심실중격결손증 -수술치험 1례-)

  • 홍기표
    • Journal of Chest Surgery
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    • v.27 no.2
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    • pp.161-165
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    • 1994
  • We have experienced a case of ventricular septal defect due to blunt chest trauma. A 22 year old male patient was admitted due to chest pain after Motor cycle accident on July 1st,1993. On 5th hospital day, sudden onset of dyspnea was noted and auscultation represented newly developed systolic murmur. A cardiac catheterization and Left ventriculogram revealed ruptured septum at the apical portion. Because there was open wound on anterior chest wall and congestive heart failure was medically controlled, the patient was discharged for elective operation. He was readmitted on August 14th, 1993.At operation, ventricular septal defect was found in apico-posterior muscular septal area, about 2.0 x 1.5 cm in size. The defect was repaired by double velour patch with interrupted suture and ventriculotomy was closed with Teflon felt. The patient`s postoperative course was uneventful and discharged 10 days postoperatively without complication. The patient have been followed up~ for 2 months. He is on functional class I with small amount of residual shunt at the ventricular septum.

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Reduction of the Accident Risk of Liquid Rocket Engine (액체로켓엔진의 사고위험 감소방안)

  • Kim, Cheul-Woong;Kim, Seung-Han;Nam, Chang-Ho;Seol, Woo-Soek
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.388-392
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    • 2008
  • Research of methods for preventing accidents and minimizing losses during the liquid rocket engine (LRE) test and its exploration is of current importance. In this paper the steps of progress to LRE accidents are defined, and methods for preventing LRE accidents and minimizing losses from accidents are considered. The suggested methods in this paper can be applied to LRE test and exploration for protecting engine system from emergency situation.

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Conservative Management and Postoperative Rehabilitation of Chronic Lateral Ankle Instability (만성 외측 족관절 불안정성의 보존적 치료와 수술적 치료 후의 재활운동)

  • Park, Young Hwan;Kim, Hak Jun
    • Journal of Korean Foot and Ankle Society
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    • v.23 no.1
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    • pp.6-11
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    • 2019
  • As a result of the increased participation in recreational and competitive sports activity, the incidence of chronic lateral instability has risen. Because chronic ankle instability can cause significant comorbidity and increase the social cost, the interest in this issue is growing. Although there are well-documented and effective surgical treatments for managing this condition, conservative treatments are a viable first option in selected patients. Through conservative treatment, surgical treatments can be reduced or delayed without necessarily affecting the overall outcome, but the failure of conservative treatment results in the need for surgical treatment to reduce the long term complications. Appropriate postoperative rehabilitation is essential for adequate functional recovery, even when surgical treatment is required.

Proprioception After Total Knee Replacement (슬관절 전치환술 이후의 고유수용성 감각 변화)

  • Kim, Jae-Hun
    • PNF and Movement
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    • v.9 no.1
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    • pp.39-45
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    • 2011
  • Purpose : The purpose of this article was to review the literature on change of knee position sense after total knee replacement intervention in knee rehabilitation. Methods : This review outlines scientific findings regarding different literature data in knee rehabilitation, and discusses proprioceptive change of knee joints after total knee replacement intervention. Result : Severe pain and diminished joint sensation may precipitate degenerative changes of knees joint, and a strong association between decreased proprioception and function has been identified in elderly patients with knee osteoarthritis. Total knee replacement(TKR) of the knee joint are effective surgical procedures in osteoarthritis patients, resulting in decreased pain, and improved physical function and quality of life in patients. After total knee replacement, joint position sensation is partially recovered, which may improve functional stability of the knee, but aspects of physical functioning are not fully restored to preoperative status. Conclusions : Thus, recovery rate in proprioception after TKR also is considered to be important because it may be a significant risk factor in failure of total knee replacement and knee rehabilitation intervention.

Physical Phenotype Analysis in Obesity Study in vivo (마우스를 이용한 비만연구에서 활용되는 물리적 표현형 분석 기술)

  • Kim, Hyunkyung;Go, Gwang-woong
    • Food Science and Industry
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    • v.51 no.1
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    • pp.37-44
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    • 2018
  • The prevalence of obesity is continually increasing in South Korea; about 1/3 of adults are diagnosed with obesity and 1/2 of adults are overweight in 2016. Abnormal body fat mass increased the risk factors of metabolic syndrome (including hypertension, type II diabetes, dyslipidemia), chronic kidney failure, osteoarthritis, and cardiovascular disease. Ministry of Food and Drug Safety (MFDS) in Korea established the validation and approval system for "functional food" based on related laws and regulations. According to the guideline of MFDS, the biomarkers for obesity study in vitro, in vivo, and clinical trial are well summarized. The analysis of physical phenotypes is necessary condition to study further molecular phenotypes and pathway analysis in vivo study. Thus, we will review currently available physical phenotype analysis; dual energy X-ray absorptiometry (DEXA) and Oxylet gas analysis will be examined in-depth.

Design of PESSRAE To Achieve Safety Integrity With FMEDA Analysis (안전무결성을 달성하기 위한 FMEDA 분석 기반 PESSRAE 설계)

  • Heo, Jeho;Kim, Gi-bong;Jung, Gi-Hyun;An, Seokchan
    • IEMEK Journal of Embedded Systems and Applications
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    • v.17 no.3
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    • pp.157-165
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    • 2022
  • As the number of the installed escalators in Korea continues to increase, the accident rate is also increasing. Therefore, it would be necessary to proactively secure safety. PESSRAE is a controller that implements safety functions as electric/electronic/programmable electronic devices to respond to risks that may occur in escalators. Safety Integrity Level (SIL) is assigned to the safety functions of PESSRAE and it must be verified that the quantitative target value according to the SIL level is satisfied. In this paper, the initial PESSRAE is analyzed using the FMEDA (Failure Mode, Effects and Diagnostic Analysis), which is a quantitative safety analysis method, and design improvement specifications are derived from the analysis in order to satisfy the quantitative target values. Based on the derived design specifications, the improved PESSRAE controller was manufactured. And the appropriateness of the design was verified experimentally in a testbed environment simulating the real environment.

A Study of Sensor Reasoning for the CBM+ Application in the Early Design Stage (CBM+ 적용을 위한 설계초기단계 센서선정 추론 연구)

  • Shin, Baek Cheon;Hur, Jang Wook
    • Journal of the Korean Society of Systems Engineering
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    • v.18 no.1
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    • pp.84-89
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    • 2022
  • For system maintenance optimization, it is necessary to establish a state information system by CBM+ including CBM and RCM, and sensor selection for CBM+ application requires system process for function model analysis at the early design stage. The study investigated the contents of CBM and CBM+, analyzed the function analysis tasks and procedures of the system, and thus presented a D-FMEA based sensor selection inference methodology at the early stage of design for CBM+ application, and established it as a D-FMEA based sensor selection inference process. The D-FMEA-based sensor inference methodology and procedure in the early design stage were presented for diesel engine sub assembly.

The Study of Predictive Diagnosis Technology Development Status and Promotion Plan for Reactor Coolant Pump (원자로냉각재펌프 예측진단 기술개발 현황 및 추진방안)

  • Hee Chan Kim
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.19 no.1
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    • pp.44-51
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    • 2023
  • The RCP is one of the main components in nuclear power plants and plays an important role in circulating coolant to the RCS system. Currently, nuclear plants are monitored using various monitoring systems. However, since they operate independently according to their functional purpose, it is not able to analyze vibration and operation/performance information comprehensively, and thus failure diagnosis accuracy is limited. In addition, these systems do not provide some important information (such as fault type, parts and cause) necessary for emergency actions, but provide only alarm information. To improve these technical problems, this study proposes a diagnosis technique (M/L, Rule-based model, Data-driven model, Narrow band model) and methodology for comprehensive analysis.

Current Opinion on Endovascular Therapy for Emergent Large Vessel Occlusion Due to Underlying Intracranial Atherosclerotic Stenosis

  • Dong-Hun Kang;Woong Yoon
    • Korean Journal of Radiology
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    • v.20 no.5
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    • pp.739-748
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    • 2019
  • For recanalization of emergent large vessel occlusions (ELVOs), endovascular therapy (EVT) using newer devices, such as a stent retriever and large-bore catheter, has shown better patient outcomes compared with intravenous recombinant tissue plasminogen activator only. Intracranial atherosclerotic stenosis (ICAS) is a major cause of acute ischemic stroke, the incidence of which is rising worldwide. Thus, it is not rare to encounter underlying ICAS during EVT procedures, particularly in Asian countries. ELVO due to underlying ICAS is often related to EVT procedure failure or complications, which can lead to poor functional recovery. However, information regarding EVT for this type of stroke is lacking because large clinical trials have been largely based on Western populations. In this review, we discuss the unique pathologic basis of ELVO with underlying ICAS, which may complicate EVT procedures. Moreover, we review EVT data for patients with ELVO due to underlying ICAS and suggest an optimal endovascular recanalization strategy based on the existing literature. Finally, we present future perspectives on this subject.