• Title/Summary/Keyword: Common-cause failure

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Clinical Observation of Acute Drug Intoxications (급성약물중독에 관한 임상적 고찰)

  • Chun, Jun-Ha;Shin, Kyung-Chul;Chung, Jin-Hong;Lee, Chong-Ki;Shim, Bong-Sup;Lee, Hyun-Woo
    • Journal of Yeungnam Medical Science
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    • v.8 no.2
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    • pp.164-173
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    • 1991
  • Clinical observations were made on 349 cases of acute drug intoxication who were visited to emergency room of Yeungnam University Hospital during recent 7 years from January 1984 to December 1990. The following results were obtained 1) Total number of cases of acute drug intoxication was 349 which was 0.39% of the total patients of the emergency room during the same period. 2) The ratio of male to female was 1.1 : 1. The age incidence was highest in the third decade(26.7%). The monthly incidence was hightest in May. Higher frequency was observed in summer season. 3) The most common drug of the intoxication was pesticides and herbicides(71.9%), the remainders were miscellaneous drugs(11.2%), sedatives(7.7%), rodenticides(6.3%) and unknown drug(3.2%) in orders. 4) The most common cause of drug intoxication was suicide(69.1%) and the others were accident, unknown cause, intention in orders. 5) Main clinical manifestations were the impairment of consciousness, nausea, vomiting and convulsion. Physical examination revealed increased pulses, increased blood pressure, miosis of the pupil and sweating. Above symptoms and signs were more prominent in pesticide intoxication. Leukocytosis, glycosuria and abnormal LFT were common findings in acute intoxications. 6) The complications were developed in 18.3% among 349 cases and the most common complication was respiratory failure, pneumonia, cardiovascular collapse and pulmonary edema in orders. 7) Overall mortality rate was 8.3% of total cases and mortality rate was highest in herbicide intoxication(22.2%).

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Reliability Analysis of Hot-Standby Sparing System with Common Cause Failures for Railway (공통고장모드를 고려한 대기 이중계 구조의 철도 시스템 신뢰도 분석)

  • Park, Chan-woo;Chae, Eunkyung;Shin, Duck-ho
    • Journal of the Korean Society for Railway
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    • v.20 no.3
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    • pp.349-355
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    • 2017
  • Failures of railway systems can result in train delays or accidents, and therefore high reliability is required to ensure safety of railway systems. To improve reliability, railway systems are designed with redundant systems so that the standby system will continue to function normally even if the primary system fails. Generally, overall system reliability can be evaluated by the reliabilities of the parts of the whole system and the reliability of the redundant system considering common failures in case of each system is not conform physical, functional and process independent. In this study, the reliability of the hot-standby sparing system is analyzed the independent systems and dependent systems with common failures. The reliability for the standby system can be effectively analysed using Markov models, which can model the redundant configuration and the state transition.

Case of Restless Leg Syndrome Patient with Chronic Kidney Failure Treated with Jakyakgamcho-tang (만성 신장병 환자의 하지불안증후군에 대한 작약감초탕 치험 1례)

  • So-Min Jung;Seong-Wook Lee;Han-Gyul Lee;Ki-Ho Cho;Sang-Kwan Moon;Woo-Sang Jung;Seungwon Kwon
    • The Journal of Internal Korean Medicine
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    • v.44 no.2
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    • pp.146-157
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    • 2023
  • Restless leg syndrome is a nervous system disorder that causes an overpowering urge to move one's legs. Symptoms of restless leg syndrome usually worsen when one tries to fall asleep and can prevent sufficient sleep. Restless leg syndrome is common in patients with chronic kidney failure and can be caused or worsened by chronic kidney failure and hemodialysis. Various medications can treat restless leg syndrome, though the long-term use of medications can cause augmentation and adverse effects. In addition, the use of dopamine agonists is limited in patients with chronic kidney failure. This is because the dose of administration should be controlled for patients with chronic kidney failure, and the treatment effect has not been clearly proven. This study reports the case of a 56-year-old male diagnosed with chronic kidney failure complaining of uncomfortable leg sensations. The patient underwent Korean medicine treatment using Jakyakgamcho-tang. The IRLS, NRS, and AIS scores were evaluation tools during treatment. This study suggested significantly improved symptoms through the individual interventions of Jakyakgamcho-tang in a restless leg syndrome patient with chronic kidney failure.

A Case of Hemolytic Uremic Syndrome Induced by Pneumococcal Infection (폐구균 감염으로 유발된 용혈성 요독 증후군 ( Hemolytic Uremic Syndrome) 1례)

  • Sim Yoon-Hee;Choi Eung-Sang;Lim In-Seok
    • Childhood Kidney Diseases
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    • v.6 no.2
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    • pp.237-242
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    • 2002
  • Hemolytic Uremic Syndrome (HUS) is the most common cause of acute renal failure in children and is comprised of the combination of hemolytic anemia, thrombocytopenia, and acute renal failure. Atypical HUS, rare in childhood, has worse prognosis than that of typical HUS and is associated with chemotherapy drug, other bacterial (especially Streptococcus pneumoniae) or viral infections, and so on. We report a case of HUS caused by pneumococcal infection in 4-year-old boy. While he was admitted with pneumonia and pleural effusion, pneumococcal infection could be revealed. Although HUS progressed rapidly, he immediately received 3-time hemodialysis and recovered completely after two weeks.

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Variable Aggregation in the ILP Design of WDM Networks with Dedicated Protection

  • Tornatore, Massimo;Maier, Guido;Pattavina, Achille
    • Journal of Communications and Networks
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    • v.9 no.4
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    • pp.419-427
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    • 2007
  • In wavelength-division-multiplexing(WDM) networks a link failure may cause the failure of several high-bit-rate optical channels, thereby leading to large data loss. Recently, various protection and restoration mechanisms have been proposed to efficiently deal with this problem in mesh networks. Among them, dedicated path protection(DPP) is a promising candidate because of its ultra-fast restoration time and robustness. In this work we investigate the issue of planning and optimization of WDM networks with DPP. Integer linear programming(ILP), in particular, is one of the most common exact method to solve the design optimization problem for protected WDM networks. Traditional ILP formalizations to solve this problem rely on the classical flow or route formulation approaches, but both these approaches suffer from a excessively high computational burden. In this paper, we present a variable-aggregation method that has the ability of significantly reducing the complexity of the traditional flow formulation. We compare also the computational burden of flow formulation with variable aggregation both with the classical flow and route formulations. The comparison is carried out by applying the three alternative methods to the optimization of two case-study networks.

RELIABILITY ANALYSIS OF DIGITAL SYSTEMS IN A PROBABILISTIC RISK ANALYSIS FOR NUCLEAR POWER PLANTS

  • Authen, Stefan;Holmberg, Jan-Erik
    • Nuclear Engineering and Technology
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    • v.44 no.5
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    • pp.471-482
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    • 2012
  • To assess the risk of nuclear power plant operation and to determine the risk impact of digital systems, there is a need to quantitatively assess the reliability of the digital systems in a justifiable manner. The Probabilistic Risk Analysis (PRA) is a tool which can reveal shortcomings of the NPP design in general and PRA analysts have not had sufficient guiding principles in modelling particular digital components malfunctions. Currently digital I&C systems are mostly analyzed simply and conventionally in PRA, based on failure mode and effects analysis and fault tree modelling. More dynamic approaches are still in the trial stage and can be difficult to apply in full scale PRA-models. As basic events CPU failures, application software failures and common cause failures (CCF) between identical components are modelled.The primary goal is to model dependencies. However, it is not clear which failure modes or system parts CCF:s should be postulated for. A clear distinction can be made between the treatment of protection and control systems. There is a general consensus that protection systems shall be included in PRA, while control systems can be treated in a limited manner. OECD/NEA CSNI Working Group on Risk Assessment (WGRisk) has set up a task group, called DIGREL, to develop taxonomy of failure modes of digital components for the purposes of PRA. The taxonomy is aimed to be the basis of future modelling and quantification efforts. It will also help to define a structure for data collection and to review PRA studies.

Etiologies, Prognostic Factors, and Outcomes of Pediatric Acute Liver Failure in Thailand

  • Getsuwan, Songpon;Lertudomphonwanit, Chatmanee;Tanpowpong, Pornthep;Thirapattaraphan, Chollasak;Tim-Aroon, Thipwimol;Wattanasirichaigoon, Duangrurdee;Treepongkaruna, Suporn
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.23 no.6
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    • pp.539-547
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    • 2020
  • Purpose: Pediatric acute liver failure (PALF) is a serious condition; however, data on PALF in developing countries are sparse, particularly concerning molecular diagnosis and liver transplantation (LT). This study aimed to determine the causes, outcomes, and prognostic factors of PALF. Methods: We retrospectively reviewed the medical records of children (age <15 years) with PALF diagnosed using the American Association for the Study of Liver Diseases criteria at our center from 2011 to 2016. The collected data included laboratory results, complications, outcomes, and potential factors associated with death and LT. Results: We included a total of 27 patients, with a median age of 2 years (interquartile range, 3 months to 4 years). Viral infection was the most common etiology (n=8, 30%), predominantly dengue infection (n=4). A total of 16 patients (59%) died and 11 patients survived (3 patients with LT). The prognostic factors associated with death or LT requirement were grade IV hepatic encephalopathy (p<0.01), hypotension (p=0.02), gastrointestinal bleeding (p=0.03), increased intracranial pressure (p=0.04), and higher peak serum lactate level (p=0.01). Peak serum lactate ≥6 mmoL/L had a sensitivity of 79% and a specificity of 88% for predicting mortality or the necessity of LT. Conclusion: Viral infection was the most common cause of PALF. The mortality rate remained high, and a considerable number of patients required LT. In addition to several clinical factors, peak serum lactate could be a potential marker for predicting poor outcomes in PALF.

Early and Late Results after Mitral Valve Replacement (승모판막 치환후 조기및 장기추적결과)

  • 김명인
    • Journal of Chest Surgery
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    • v.25 no.2
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    • pp.149-157
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    • 1992
  • Total 145 cases mitral vlave replacement were performed in Department of Thoracic and Cardiovascular Surgery in Chungnam National University Hospital during the period from May 1983 to July 1991. Sixty-one patients were male and 84 patients were female and the range of age was from 12 to 66 years old with the mean of 37.9[$\pm$11.6] years. Valvular lesions were 49 cases of mitral stenosis, 18 cases of regurgitation and 78 cases of combined lesion. Used valve were Ionescu-Shiley[42 cases], Bjork-Shiley[49 cases], Inact[6 cases], St. Jude Medical[11 cases] and CarboMedics[37 cases]. Mean size of valve was 29.8$\pm$1.68mm. Early morality was 13.8%[20 cases] and low output syndrome was most common cause[9 cases]. Age, functional classification and biventricular hypertrophy were risk factors. All survived cases were followed up without missing. Mean follow up period were 3 years and 3 months. Total 14 cases of death[9.7%] were observed and heart failure, unexplained sudden death and bleeding were the causes in that order. Common late complications were heart failure and bleeding related with anticoagulation. Actuarial survival rate at 5 years was 83$\pm$5.4% in overall, 78$\pm$7.2% in tissue valve group, 87$\pm$6.8% in mechanical valve group. The actuarial freedom rate from thromboembolism at 7 years was 89$\pm$8.3% in overall, 86$\pm$9.9% in tissue valve group and 97$\pm$1.9% in mechanical valve group. Actuarial freedom rate from bleeding at 5 years with anticoagulation was 88.9$\pm$4.2% in overall, 96$\pm$3.9% in tissue valve group, 86$\pm$4.6% in mechanical valve group. Reoperation was done in 3 cases with heart failure with tricuspid regurgitation and thromboembolism in 2 cases. The functional status of survived cases was I or II.

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Patient outcomes and prognostic factors associated with colonic perforation surgery: a retrospective study

  • Lee, Do-bin;Shin, Seonhui;Yang, Chun-Seok
    • Journal of Yeungnam Medical Science
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    • v.39 no.2
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    • pp.133-140
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    • 2022
  • Background: Despite advances in surgery and intensive perioperative care, fecal peritonitis secondary to colonic perforation is associated with high rates of morbidity and mortality. This study was performed to review the outcomes of patients who underwent colonic perforation surgery and to evaluate the prognostic factors associated with mortality. Methods: A retrospective analysis was performed on 224 consecutive patients who underwent emergency colonic perforation surgery between January 2008 and May 2019. We divided the patients into survivor and non-survivor groups and compared their surgical outcomes. Results: The most common cause of colon perforation was malignancy in 54 patients (24.1%), followed by iatrogenic perforation in 41 (18.3%), stercoral perforation in 39 (17.4%), and diverticulitis in 37 (16.5%). The sigmoid colon (n=124, 55.4%) was the most common location of perforation, followed by the ascending colon, rectum, and cecum. Forty-five patients (20.1%) died within 1 month after surgery. Comparing the 179 survivors with the 45 non-survivors, the patient characteristics associated with mortality were advanced age, low systolic blood pressure, tachycardia, organ failure, high C-reactive protein, high creatinine, prolonged prothrombin time, and high lactate level. The presence of free or feculent fluid, diffuse peritonitis, and right-sided perforation were associated with mortality. In multivariate analysis, advanced age, organ failure, right-sided perforation, and diffuse peritonitis independently predicted mortality within 1 month after surgery. Conclusion: Age and organ failure were prognostic factors for mortality associated with colon perforation. Furthermore, right-sided perforation and diffuse peritonitis demonstrated a significant association with patient mortality.

Robustness Estimation for Power and Water Supply Network : in the Context of Failure Propagation (피해파급에 대한 고찰을 통한 전력 및 상수도 네트워크의 강건성 예측)

  • Lee, Seulbi;Park, Moonseo;Lee, Hyun-Soo
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.3
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    • pp.33-42
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    • 2018
  • In the aftermath of an earthquake, seismic-damaged infrastructure systems loss estimation is the first step for the disaster response. However, lifeline systems' ability to supply service can be volatile by external factors such as disturbances of nearby facilities, and not by own physical issue. Thus, this research develops the bayesian model for probabilistic inference on common-cause and cascading failure of seismic-damaged lifeline systems. In addition, the authors present network robustness estimation metrics in the context of failure propagation. In order to quantify the functional loss and observe the effect of the mitigation plan, power and water supply system in Daegu-Gyeongbuk in South Korea is selected as case network. The simulation results show that reduction of cascading failure probability allows withstanding the external disruptions from a perspective of the robustness improvement. This research enhances the comprehensive understanding of how a single failure propagates to whole lifeline system performance and affected region after an earthquake.