• Journal of Chest Surgery
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• 제32권6호
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• pp.532-535
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• 1999

Background: The purpose of this study was to evaluate and analyze the surgical techniques and postoperative complications in patients undergoing operations for descending thoracic aortic aneurysms. Material and Method: The data of 22 major operations between March 1987 and August 1997 were retrospectively reviewed. Result: There were 18 men and 4 women with a mean age of 49 years (range 33 years to 82 years). The cause of the aneurysm was aortic dissection in 13 patients, atherosclerosis in 3, mycotic in 3, trauma in 2 and uncertain in 1. The operative techniques were resection and graft replacement in 16, axillofemoral bypass graft in 2, femorofemoral bypass graft in 2, exclusion, aneurysmorrhaphy in 1 and transfemoral stent insertion in 1. During the operation, 16 cases were performed under total aortic clamp. Among the 16 patients, femorofemoral bypass was used in 14 cases and previously made shunt in 2 cases. The mean total aortic clamp time was 91 minutes and the mean extracorporeal circulation time was 116 minutes. One death occurred in an excluded patient on the 52 postoperative day due to a rupture of the aneurysm. Postoperative complications were paraplegia in 1 case, acute renal failure in 1 case and acute respiratory failure in 1 case. Conclusion: Although surgical treatment of the descending thoracic aneurysm has many postoperative complications, good surgical results can be achieved with a proper patient selection and fine surgical techniques.

• Radiation Oncology Journal
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• 제2권2호
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• pp.191-202
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• 1984

Biological behavior and treatment results of 33 patients with Adenoid Cystic Carcinoma (ACC) in the Head and Neck at Yonsei Cancer Confer for 10 years between 1971 and 1980 were retrospectively analysed. Most common, primary site was minor salivary glands such as maxillary sinus, nasal cavity and base of tongue. The typical biological behavior of these tumors was very slowly in growth with long time of duration(mean 19 months) from 1 month to 10 years and more frequent of nerve invasion but rare invasion of neck nodes. Local control and failure pattern in the results of treatment, 16 of 17 patients with irradiation alone were seen complete or partial response but 5 cases of locoregional recurrence, 2 cases of failure of neck node and 4 cases of distant metastasis as lung and brain. On the other hand, among 10 cases of surgery and postoperative irradiation, 2 cases of locoregional failure and 3 cases of distant metastasis as lung and bone. 2 of 4 cases with surgery alone were recurred within primary site. Actuarial overall NED survival at 3 ana 10 years were $52.6\%$ and $42.8\%$, respectively. Survival rate of 10 Patients with surgery and Postoperative irradiation was more high than 17 Patients of radiation alone. Therefore, we have known that surgery with postoperative adjunctive irradiation is most effective treatment modality of adenoid cystic carcinoma in the head and neck. Primary site, treatment modality and with or without nerve ana bone invasion have influenced on prognosis.

• Transactions of the Korean Society of Automotive Engineers
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• 제13권5호
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• pp.7-18
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• 2005

Over the past twenty years, the maintenance system has been developed and its importance has been increased. For the effective maintenance of the urban transit, we have developed the maintenance system based on the concept of RCM(Reliability Centered Maintenance). RCM analysis is a systematic approach to developing a cost-effective maintenance strategy based on the various components's reliability of the system in question. It is performed according to process that includes the following steps; definition of function and functional failures of the systems, construction of RB D(Reliability Block Diagram), performance of FMEA(Failure Modes & Effects Analysis) and calculation of the reliability index. The final process of RCM is to determine appropriate failure maintenance strategies. This paper aims to define the procedure of maintenace based on the concept of RCM for urban transit. The key for a successful maintenance system is an automated scheduling to the maximum extent possible and timely executions. The developed system issues maintenance plan and repair request based on analyzed data and maintenance experience.

• The Journal of the Korea institute of electronic communication sciences
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• 제6권3호
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• pp.397-404
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• 2011

In this research, wish to suggest method to embody system that can accommodate defect of PLC and find actual propriety. Defect permission control system minimizes production damage because enables repair and checking without discontinuance and improve believability about whole system. Propose duplexing of system to embody this fault tolerant system. Therefore, composed control system that can permit defect or breakdown duplexings of various module proposing this system, and confirms to simulation and actuality kiln of defect permission control system through an application experiment, and compares for mean time between defect by estimate and defect special quality and system configuration of failure(failure) to improve believability of PLC control system together. In proposed system expression method and system mode and relation with operation mode, error discovery mode and switching tube of duplexing mode, and PLC's central processing unit of node study algorithm about master-standby conversion driving and continuous operation of 2 channels method that have 2 that is not one and deduced continuous operation method and result about defect permission in this algorithm and applies this result to actuality kiln control system and confirms continuous operation about PLC defect permission.

• The Journal of Korean Academy of Prosthodontics
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• 제29권2호
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• pp.195-209
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• 1991

When the porcelain fused to metal restorations were fractured at the metal interface, various techniques and materials for intraoral porcelain repair have been suggested. The purpose of this study was to investigate the effect of metal surface treatment method and water storage on the shear bond strength of four porcelain repair systems. : Clearfil(Kuraray), All-bond(Bisco), Superbond C & B(Sun Medical), Panavia OP(Kuraray). After the metal surfaces of the specimens were sandblasted by aluminum oxide or roughened by diamond point, they were stored in double deionized water(24 Hr., $37^{\circ}C$) and thermocycling was performed(24 Hr., 1024 cycles), and again half of specimes were stored in water bath(2 Months, $37^{\circ}C$). Mean shear bond strength and mode of failure were recorded. The results of this study were obtained as follows : 1. Differences were observed between the sandblasted and diamond - treated specimens in Clearfil, All-bond, and Superbond. No statistically significant differences were observed in Panavia. 2. The 2-month storage time significantly affected the bond strength of All-bond and Superbond. No statistically significant differences were observed in Clearfil and Panavia. 3. The failures were observed at the interface between opaque resin and the metal in Clearfil and All-bond. 4. The failures were observed at the interface between opaque resin and veneered resin in Panavia. The failures were observed at the interface between opaque resin and veneered resin in Superbond, but 40% of them were fractured at the interface between the metal and opaque resin after 2-month storage time.

• Corrosion Science and Technology
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• 제12권2호
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• pp.93-101
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• 2013

The object of this work is to establish an electrochemical noise(EN) measurement technique combined with a direct current potential drop(DCPD) method for monitoring of localized corrosion cracking of nickel-based alloy, and to analyze its mechanism. The electrochemical current and potential noises were measured under various conditions of applied stress to a compact tension specimen in a simulated primary water chemistry of a pressurized water reactor. The amplitude and frequency of the EN signals were evaluated in both time and frequency domains based on a shot noise theory, and then quantitatively analyzed using statistical Weibull distribution function. From the spectral analysis, the effect of the current application in DCPD was found to be effectively excluded from the EN signals generated from the localized corrosion cracking. With the aid of a microstructural analysis, the relationship between EN signals and the localized corrosion cracking mechanism was investigated by comparing the shape parameter of Weibull distribution of a mean time-to-failure.

• Journal of Chest Surgery
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• 제16권1호
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• pp.75-82
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• 1983

This report is concerned to our experience of 10 cases of open heart surgery under the extracorporeal circulation at the Department of Thoracic and Cardiovascular Surgery, Capital Armed Forces General Hospital during the period between May, 1982 and February, 1983. 1. Six cases were male and two cases were female. Age was varied from 21 years to 50 years and mean age was 34 years. 2. The cases included 2 Ventricular Septal Defects, 1 Atrial Septal Defect, I Tetralogy of Fallot and 6 acquired valvular heart diseases. 3. The surgical managements were 3 primary repairs for Ventricular Septal Defects and Atrial Septal Defect, I total correction for Tetralogy of Fallot and 6 mitral valve replacements with bovine xenograft by Ionescu-Shiley combining 3 Tricuspid annuloplasties [ De Vega method ] and 1 deauricularization of left atrial appendage for acquired valvular heart diseases. 4. The average cardiopulmonary bypass time was 37 minutes for acyanotic congenital heart diseases and 92 minutes for cyanotic heart disease and acquired valvular heart diseases. And the average aortic cross clamping time was 19 minutes for the former and 70 minutes for the latter. 5. Postoperatively, there were 1 hemolytic anemia, 1 congestive heart failure, 1 hemolytic jaundice and 1 thermal burn as complications, but there was no operative mortality. 6. All patients received valve replacement were recommended anticoagulation with Persantin and Aspirin.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제12권1호
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• pp.1-9
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• 2008

The Logistic cone is studied as a most desirable for the software testing effort. Assuming that the error detection rate to the amount of testing effort spent during the testing phase is proportional to the current error content, a software-reliability growth model is formulated by a nonhomogeneous Poisson process. Using this model the method of data analysis for software reliability measurement is developed. After defining a software reliability, This paper discusses the relations between testing time and reliability and between duration following failure fixing and reliability are studied SRGM in several literatures has used the exponential curve, Railleigh curve or Weibull cure as an amount of testing effort during software testing phase. However, it might not be appropriate to represent the consumption curve for testing effort by one of already proposed curves in some software development environments. Therefore, this paper shows that a logistic testing- effort function can be adequately expressed as a software development/testing effort curve and that it gives a good predictive capability based on real failure data.

• Journal of the Korean Institute of Telematics and Electronics B
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• 제28B권10호
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• pp.807-821
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• 1991

A mulitpath MIN(Multistage Interconnection Network), CSMP(Chained Shuffle Multi-Path) network, is proposed, having fault-tolerance and dynamic reroutability. The number of stages and the number of links between adjacent stagges are the same as in single path MINs, so the overall hardware complexity is considerably reduced in comparison with other multipath MINs. The CSMP networks feature links between switches belonging to the same state, forming loops of switches. The network can tolerate multiple faults, up to (N/4)*(log$_2$N-1), having occured in any stages including the first and the last ones(N:NO. of input). To analyze reliability, terminal reliability (TR) and mean time to failure( MTTE) age given for the networks, and the TR figures are compared to those of other static and dynamic rerouting multipath MINs. Also the MTTE figures are compared. The performance of the proposed network with respect to its bandwidth (BW) and probability of acceptance(PA) is analyzed and is compared to that of other more complex multipath MINs. The cost efficiency analysis of reliability and performance shows that the network is more cost-effective than other previously proposed fault-tolerant multipath MINs.

• Journal of Chest Surgery
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• 제53권6호
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• pp.392-399
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• 2020

Background: Surgical treatment of empyema thoracis in patients with chronic kidney disease is challenging, and few studies in the literature have evaluated this issue. In this study, we aim to report the surgical outcomes of empyema and to analyze factors predicting perioperative mortality in patients with chronic kidney disease. Methods: This retrospective study included data from 34 patients with chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 ㎡ for 3 or more months) who underwent surgery for empyema between 2012 and 2020. An analysis of demographic characteristics and perioperative variables, including complications, was carried out. Postoperative mortality was the primary outcome measure. Results: Patients' age ranged from 20 to 74 years with a 29-to-5 male-female ratio. The majority (n=19, 55.9%) of patients were in end-stage renal disease (ESRD) requiring maintenance hemodialysis. The mean operative time was 304 minutes and the mean intraoperative blood loss was 562 mL. Postoperative morbidity was observed in 70.5% of patients (n=24). In the subgroup analysis, higher values for operative time, blood loss, intensive care unit stay, and complications were found in ESRD patients. The mortality rate was 38.2% (n=13). In the univariate and multivariate analyses, poor performance status (Eastern Cooperative Oncology Group >2) (p=0.03), ESRD (p=0.02), and late referral (>8 weeks) (p<0.001) significantly affected mortality. Conclusion: ESRD, late referral, and poor functional status were poor prognostic factors predicting postoperative mortality. The decision of surgery should be cautiously assessed given the very high risk of perioperative morbidity and mortality in these patients.