• Title/Summary/Keyword: Mean Time Between Failure

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Development of Vancomycin Initial Dosage Guidelines to Achieve New Target Ranges (Vancomycin 초기 투여 용량 개선 방안)

  • Yoo, Jae-Young;Kim, Jung-Hyun;Lee, Yong-Won;Kim, Eun-Yeong;Sohn, Kie-Ho
    • Korean Journal of Clinical Pharmacy
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    • v.20 no.3
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    • pp.221-228
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    • 2010
  • In 2009, American Journal of Health-System Pharmacy (AJHP) recommended that targeting vancomycin trough concentrations of 10 mg/L or more because of therapeutic failure and potential risk of developing vancomycin resistance. Therefore, new dosage guidelines that could achieve to these higher target were needed. The aims of this study were to develop dosage guidelines targeting new vancomycin trough concentration and to evaluate the performance of these new guidelines. All data analysis were performed using NONMEM(R). Population pharmacokinetic model was first developed from vancomycin dosage and concentration data collected retrospectively during routine therapeutic drug monitoring in 441 patients, then new vancomycin dosage guidelines were developed by using the model to predict vancomycin trough and peak concentrations in a simulated dataset. The estimates, such as, vancomycin concentration trough level, time to achieve target level, mean error were performed to evaluate and compare difference between conventional dosage and new dosage guidelines. The proposed dosage guidelines were predicted to achieve 43.5% of vancomycin trough level within 10~20 mg/L, which is significantly higher than current guidelines (26.3%). Time to achieve target trough level was 19.4 hours in new guidelines comparing to 93.1 hours in the conventional dosage. Thus, new vancomycin dosage guidelines have been developed to achieve new target trough concentrations earlier and more consistently than conventional guidelines.

The Study of Software Reliability Model from the Perspective of Learning Effects for Burr Distribution (Burr분포 학습 효과 특성을 적용한 소프트웨어 신뢰도 모형에 관한 연구)

  • Kim, Dae-Soung;Kim, Hee-Cheul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4543-4549
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    • 2011
  • In this study, software products developed in the course of testing, software managers in the process of testing software test and test tools for effective learning effects perspective has been studied using the NHPP software. The Burr distribution applied to distribution was based on finite failure NHPP. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than automatic error that is generally efficient model could be confirmed. This paper, a numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error and $R^2$.

The Study of NHPP Software Reliability Model from the Perspective of Learning Effects (학습 효과 기법을 이용한 NHPP 소프트웨어 신뢰도 모형에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.11 no.1
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    • pp.25-32
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    • 2011
  • In this study, software products developed in the course of testing, software managers in the process of testing software test and test tools for effective learning effects perspective has been studied using the NHPP software. The Weibull distribution applied to distribution was based on finite failure NHPP. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than automatic error that is generally efficient model could be confirmed. This paper, a numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error and $R_{sq}$.

Understanding the Trilemma in Inter-Korea Economic Cooperation (남북한 경제협력의 불가능 삼각정리와 실천적 협력방안)

  • Han, Hongyul
    • Analyses & Alternatives
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    • v.2 no.1
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    • pp.5-29
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    • 2018
  • Models of South-North Korean economic integration have the problem of circular reasoning. While many studies argue that South-North Korean economic integration would contribute to alleviate security risks in the Korean peninsular, they emphasize the success of any economic model of inter-Korean economic integration is subject to favorable geo-political and security environment. It is a failure in distinguishing between goals and constraints. After identifying three major goals of South-North Korean economic cooperation, this study shows the trilemma among the goals; they are 1) formation of a complete economic community, 2) maintaining independent sovereignty of the two Koreas, 3) promotion of mutual economic interests. The trilemma suggests that it is theoretically impossible to achieve the above three goals at the same time. Only two goals are achievable simultaneously. This study argues that the most practical option is to pursue the combination of goals 2) and 3) considering the complex political and security environment around the Korean peninsular. Recognizing that North Korea is the least developed country in the Northeast Asia region, South Korea's initiatives for inter-Korean economic cooperation should focus on assisting industrialization and integration of the North Korea economy into the Northeast Asian regional production sharing structure. In view of the 'flying geese model' of the sequential industrialization in the region, the least developed economic status of North Korea can partially be explained by its failure to participate in the production network in the region as well as lack of effective implementation of appropriate industrial policy. Therefore, promotion of industrialization of North Korea should be the immediate goal of economic cooperation between North and South Korea. It is an interesting fact that North Korea has rapidly expanded its apparel exports in recent years. It could mean that the North Korean economy is actively responding to the dynamics of international comparative advantage structure, although the production activities are limited to exports to China since the closure of the Gaesung Industrial Complex. The recent increase in apparel export is a starting point for incorporating the Easy Import Substitution fulfilling both domestic and neighboring regional demand of North Korea. It could help integrate North Korea's industry into the production network of Northeast Asia. An immediate policy implication is that the economic cooperation between the two Koreas should focus on facilitating this process and supporting North Korea's industrial policy through South Korea's contribution of capital, technology, and service intermediary inputs.

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In-Hospital Outcomes of Acute Renal Failure Requiring Continuous Renal Replacement Therapy in Patients with On-pump CABG (심폐기 가동하 관상동맥우회술 후 발생한 급성신부전 환자들에 있어 지속적 신대체요법의 병원 내 결과)

  • Kim, Young-Du;Park, Kuhn;Kang, Chul-Ung;Yoon, Jeong-Seob;Moon, Seok-Whan;Wang, Young-Pil;Jo, Kuhn-Hyun
    • Journal of Chest Surgery
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    • v.40 no.1 s.270
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    • pp.32-36
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    • 2007
  • Background: Although acute renal failure (ARF) after coronary artery bypass graft (CABG) is relatively rare, but devastating complication with high mortality. Our study aims to evaluate the effectiveness of early application of CRRT in patients with ARF which developed after on-pump CABG. Material and Method: Two hundred and eighty seven patients underwent isolated on-pump CABG between May 2002 and Feb. 2006 at our institution, of whom 15 (5.2%) needed CRRT (11 patients for postoperatively developed ARF and the remaining 4 patients with preexisting dialysis-dependent chronic renal failure (CRF) for postoperative hemodynamic and metabolic control). Criteria for early application of CRRT were as follows; decreased urine output less than 0.5cc/h/kg for 2 consecutive hours and elevated serum creatinine level greater than 2.0 mg/dL. Result: The incidence of ARF requiring CRRT after on-pump CABG was 3.9% (11/283) and the overall hospital mortality of patient with CRRT was 33.3% (5/15). Of 5 deaths, 4 were patients with postoperatively developed ARF, and 1 was a patient with pre-existing dialysis-dependent CRF patient. The mean time between the operation and the initiation of CRRT was $25.8{\pm}5.8$ hours and the mean duration of CRRT was $62.1{\pm}41.2$ hours. Of the 7 survivors who were not on dialysis-dependent preoperatively, 6 patients fully recovered renal function during hospital stay and 1 patient required permanent renal supportive treatment after discharge from hospital. Conclusion: Early application of CRRT could maintain stable postoperative hemodynamic status and make outcomes better than those of previous reports in patients with ARF which developed after on-pump CABG.

Seq2Seq model-based Prognostics and Health Management of Robot Arm (Seq2Seq 모델 기반의 로봇팔 고장예지 기술)

  • Lee, Yeong-Hyeon;Kim, Kyung-Jun;Lee, Seung-Ik;Kim, Dong-Ju
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.3
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    • pp.242-250
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    • 2019
  • In this paper, we propose a method to predict the failure of industrial robot using Seq2Seq (Sequence to Sequence) model, which is a model for transforming time series data among Artificial Neural Network models. The proposed method uses the data of the joint current and angular value, which can be measured by the robot itself, without additional sensor for fault diagnosis. After preprocessing the measured data for the model to learn, the Seq2Seq model was trained to convert the current to angle. Abnormal degree for fault diagnosis uses RMSE (Root Mean Squared Error) during unit time between predicted angle and actual angle. The performance evaluation of the proposed method was performed using the test data measured under different conditions of normal and defective condition of the robot. When the Abnormal degree exceed the threshold, it was classified as a fault, and the accuracy of the fault diagnosis was 96.67% from the experiment. The proposed method has the merit that it can perform fault prediction without additional sensor, and it has been confirmed from the experiment that high diagnostic performance and efficiency are available without requiring deep expert knowledge of the robot.

Wilson's Disease in Bangladeshi Children: Analysis of 100 Cases

  • Rukunuzzaman, Md.
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.18 no.2
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    • pp.121-127
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    • 2015
  • Purpose: To evaluate clinical and laboratory profile of Wilson's disease (WD) in children. Methods: This cross sectional study was conducted at Bangabandhu Sheikh Mujib Medical University Hospital. Bangladesh, over a period of 3 years. One hundred consecutive children of WD between 3 to 18 years of age were evaluated. Results: Mean age was $8.5{\pm}1.5years$. Male female ratio was 2:1. Ninety-one percent of patients were Muslim and 9% Hindu. A total of 53% cases of hepatic WD presented between 5 to 10 years of age and most of the neurologic WD manifested in 10-15 years age group. Sixty-nine children presented only with hepatic manifestations, 6 only with neurological manifestations, 14 with both hepatic and neurological manifestation, 10 children was asymptomatic and 1 patient presented with psychiatric features. WD presented as chronic liver disease (CLD) in 42%, CLD with portal hypertension in 34%, acute hepatitis in 20% and fulminant hepatic failure in 4% cases. Stigmata of CLD were found in 18% patients. Keiser-Fleischser ring was found in 76% total patients. Elevated serum transaminase was found in 85% cases, prolonged prothrombin time in 59% cases and hypoalbuminaemia in 53% cases. A total of 73% patients had low serum ceruloplasmin, basal urinary copper of >$100{\mu}g/day$ was found in 81% cases and urinary copper following penicillamine challenge of >$1,200{\mu}g/day$ was found in 92% cases. Conclusion: Majority of studied WD children presented with hepatic manifestation of which 76% presented with CLD. Any child presented with jaundice after the age of 3 years should be investigated for WD.

Surgical treatment of myasthenia gravis (중증 근무력증의 외과적 치료)

  • 이광선
    • Journal of Chest Surgery
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    • v.27 no.7
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    • pp.610-616
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    • 1994
  • Myasthenia gravis is a rare condition, affecting only 1/75000. It is characterized by weakness and fatigue of the voluntary muscles due to impaired neuromuscular transmission at the acetylcholine receptor site. It is probably caused by an autoimmune mechanism leading to reduction of the available nicotinic acetylcholine receptors at the neuromuscular junction. A relationship between the thymus and myasthenia gravis was suggested by Weigert in 1901, and Blalock was the first to report the efficiency of thymectomy in the treatment of myasthnia gravis in 1939. Since that time, thymectomy has become increasingly important in managing patients with myasthenia gravis. Fourteen patients with myasthenia gravis underwent thymectomy between September 1987 and March 1994 and got the following results; 1. The sex distribution was 10 females and 4 males with ages ranging from 15 to 51 years[mean, 34.8 years]. 2. Clinical manifestation of ocular symptoms were seen in all cases, dysphagia in 12[85.7%], extremity weakness in 11 [78.6 %], and dyspnea in 3 [21.4 %]. 3. According to the modified Osserman`s classification, 8 patients were in group IIb, 3 in IIa, 2 in I and 1 in IIc, respectively. 4. Histopathologic examination of the resected thymuses revealed hyperplasia in 8 patients, benign thymoma in 3, and malignant thymoma in 3. 5. There were no perioperative or immediate postoperative deaths but one patient died about two months after the thymectomy due to respiratory failure. 6. During the follow-up period, 11 patients [78.6 %] showed clinical improvement. Among them, 4 cases [28.6 %] showed complete remission, 3 [21.4 %] showed marked improvement, and 4 [28.6 %] showed subjective improvement. 7. Among the 8 patients with thymic hyperplasia, clinical improvement was noticed in 7 patients 5 %]. Among the 6 patients with thymoma, 4 patients [66.7 %] showed improvement.

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Reliability Analysis Using Field-Data of 5.56 mm Rifle (야전운용제원을 이용한 5.56 mm 소총 신뢰도 분석)

  • Shin, Tae-Sung;Seo, Hyun-Soo;Lee, Ho-Jun;Choi, Si-Young;Gil, Hyeon-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.584-591
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    • 2020
  • Reliability is an important factor in weapons systems. Low reliability causes the weapons system to fail to function properly, which directly leads to the weakening of combat capability. This paper classifies the structure of the 5.56 mm rifle, which is currently used by the Korean army, into a total of seven assemblies and describes the eight functions necessary for the rifle to operate normally. In addition, the concept of reliability was defined as the MRBF, and the Poisson process model and TTT plot were explained as a reliability analysis theory for the repair function system. Next, the field-data obtained by defining failure as the replacement of parts other than periodic exchange of parts were refined, and the reliability was analyzed by entering the refined field operation specifications into the Minitab program. As a result, the reliability of the rifle was determined to be 251.73. The assembly parts that required improvement was identified as the barrel, lower body, and butt stock assembly, and 10 detailed parts needed to be improved. Finally, the limits of the reliability analysis using the field-data currently available for small caliber firearms were considered.

Treatment Results of Adjuvant Radiotherapy and Chemotherapy in Breast Cancer Patients with Positive Axillary Nodes (액와 림프절에 전이된 유방암 환자에서 수술 후 방사선치료 및 항암 약물 요법의 치료 성적)

  • Shin, Hyun-Soo;Suh, Chang-Ok
    • Radiation Oncology Journal
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    • v.18 no.4
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    • pp.265-276
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    • 2000
  • Purpose : Between January 1983 and December 1988, 218 female Patients with known breast cancer and positive axillary nodes were treated with adjuvant radiotherapy and chemotherapy following radical mastectomy. Treatment results were retrospectively analysed at the Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University of College of Medicine. Materials and Methods : The patients were classified into 3 groups; group I included II patients treated with adjuvant chemotherapy alone; in group 2, 52 patients treated with radiotherapy alone; and in group 3, n patients treated with combined chemo-radiotherapy. The mean age was 44 years and ranged from 27 to 70. The median follow-up time was 51 months. Results :Seven-year relapse free and overall survival rates were 56$\%$ and 67$\%$; in group 1, 50$\%$ and 56$\%$ in group 2, 51$\%$ and 65$\%$ and in group 3, 62$\%$ and 75$\%$ respectively. This difference was not statistically significant(p<0.05). The loco-regional failure rates were 13$\%$ and distant failure rates were 33$\%$. There was less risk of loco-regional failure in group 2 and 3 which included radiotherapy (p<0.05). But there was no significantly difference in the rates of distant failure( p>0.05). By univariate analysis, the only significant prognostic factor affecting relapse-free survival was the percentage of positive axillary nodes; and the overall survival significantly correlated with the primary tumor site, the number or percentage of positive axillary nodes, and stage. But in multivariate analysis, the only significant prognostic factor was treatment modality. By univariate analysis of prognostic factors affecting the rates of overall failure and distant failure, the significant prognostic factors was the percentage of positive axillary nodes; and the risk of the loco-regional failure significantly correlated with the treatment modality. Conclusion :In conclusion, these results suggest a potential for decreasing the risk of loco-regional failure with the addition of postoperative radiotherapy to chemotherapy in the premenopausal patients, and in the patients with number or percentage of positive nodes more than 4 or 1/3. The results of this study suggest that the combined chemo-radiotherapy as adjuvant treatment following radical mastectomy was the most effective modaliw in groups of 2$\~$5 cm sized tumor, stage IIB, and in patients with more than 4 or 1/3 of number or percentage of positive nodes.

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