• Journal of Gastric Cancer
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• v.10 no.4
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• pp.241-246
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• 2010

Purpose: Laparoscopy-assisted gastrectomy (LAG) has become a technically feasible and safe procedure for early gastric cancer treatment. LAG is being increasingly performed in many centers; however, there have been few reports regarding LAG at low-volume centers. The aim of this study was to report our early experience with LAG in patients with gastric cancer at a low-volume center. Materials and Methods: The clinicopathologic data and surgical outcomes of 39 patients who underwent LAG for gastric cancer between April 2007 and March 2010 were retrospectively reviewed. Results: The mean age was 68.3 years. Thirty-one patients had medical co-morbidities. The mean patient ASA score was 2.0. Among the 39 patients, 4 patients underwent total gastrectomy and 35 patients underwent distal gastrectomy. The mean blood loss was 145.4 ml and the mean operative time was 259.4 minutes. The mean time-to-first flatus, first oral intake, and the postoperative hospital stay was 2.8, 3.1, and 9.3 days, respectively. The 30-day mortality rate was 0%. Postoperative complications developed in 9 patients, as follows: anastomotic leakage, 1; wound infection, 1; gastric stasis, 2; postoperative ileus, 1; pneumonia, 1; cerebral infarction, 1; chronic renal failure, 1; and postoperative psychosis, 1. Conclusions: LAG is technically feasible and can be performed safely at a low-volume center, but an experienced surgical team and careful patient selection are necessary. Furthermore, for early mastery of the learning curve for LAG, surgeons need education and training in addition to an accumulation of cases.

• Earthquakes and Structures
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• v.12 no.4
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• pp.469-478
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• 2017

This paper summarizes estimated seismic response results from three-dimensional nonlinear inelastic time-history analyses of some steel buckling-restrained braced (BRB) structures taking into account soil-structure interaction (SSI). The response results involve mean values for peak interstorey drift ratios, peak interstorey residual drift ratios and peak floor accelerations. Moreover, mean seismic demands in terms of axial force and rotation in columns, of axial and shear forces and bending moment in BRB beams and of axial displacement in BRBs are also discussed. For comparison purposes, three separate configurations of the BRBs have been considered and the aforementioned seismic response and demands results have been obtained firstly by considering SSI effects and then by neglecting them. It is concluded that SSI, when considered, may lead to larger interstorey and residual interstorey drifts than when not. These drifts did not cause failure of columns and of the BRBs. However, the BRB beam may fail due to flexure.

• Clinical and Experimental Reproductive Medicine
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• v.10 no.2
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• pp.13-23
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• 1983

In recent days, family planning is not only a problem limitted to our country but an important problem for the while world to solve. Up to present, various methods of sterilization have been developed for population control. When a patient with a previous tubal sterilization by operative method develops any symptoms and signs of pregnancy, we strongly consider it ectopic pregnancy and intrauterine pregnancy. As the cause of sterilization failure, we think that the tubal loop sloughs away and tubal ends either unite and recanalization results or heal and failure of union results in fistula. This present study considered of the 34 cases of ectopic pregnancies and 2 cases of intrauterine pregnancies after tubal sterilization by laparoscopy and Pomeroy's method, at the Dept. of Gynecol. in Kyung Hee University Hospital, during 6 years from Jan. 1977 to Dec. 1982. Authors take result in this study retrospectively. 1. Mean age was 33.7 years for the laparoscopic tubal sterilization group, 31.5 years for the Pomeroy tubal sterilization group. 2. The number of mean gravida and parity at the sterilization was 4.9, 2.8 for the laparoscopic tubal sterilization group, 4.2, 2.2 for the Pomeroy tubal sterilization group, :respectively. 3. The number of mean artificial abortion at the sterilization was all 2.2 for the laparoscopic and Pomeroy tubal sterilization groups. 4. Mean intervals from the tubal surgery to the incidental pregnancy was 3.2 years for the laparoscopic tubal sterilization group, and 3.8 years for the Pomeroy tubal sterilization group. 5. 63.3% of the laparoscopic tubal sterilization group had problem of inadequate tubal ligation, in comparison to having no inadequate problem in the Pomeroy tubal sterilization group. 6. The previous tubal sterilized scar was found to be 6 cases (17.6%) of inner portion, 15 cases (44.4%) of midportion, 13 cases (38.2%) of outer portion at the time of operation. The tubal site of ectopic pregnancy was found to be 23 cases (67.6%) of ampullary portion,S cases ( 4.7%) of isthmic and fimbrial portion, respectively. 7. The causes of table sterilization failure were, in order of frequency, technical error (19 cases), fistula formation (6 cases) and recanalization (5 cases) for the laparoscopic tubal sterilization group and fistula formation (2 cases), technical error (l case), recanalization (l case) fo the Pomeroy tubal sterilization group. 8. As the new applicated contraceptive method in incidental pregnant patient, Authors used 2 gravigard insertion for the two intrauterine pregnancy and 34 Pomeroys' tubal ligation, 2 total abdominal hysterectomy (due to associated pelvic inflammatory disease) for the 36 tubal pregnancy.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.89-96
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• 2006

Recent ULSI and multilevel structure trends in microelectronic devices minimize the line width down to less than $0.25{\mu}m$, which results in high current densities in thin film interconnections. Under high current densities, an EM(electromigration) induced failure becomes one of the critical problems in a microelectronic device. This study is to improve thin film interconnection materials by investigating the EM characteristics in Ag, Cu, Au, and Al thin films, etc. EM resistance characteristics of Ag, Cu, Au, and Al thin films with high electrical conductivities were investigated by measuring the activation energies from the TTF (Time-to-Failure) analysis. Optical microscope and XPS (X-ray photoelectron spectroscopy) analysis were used for the failure analysis in thin films. Cu thin films showed relatively high activation energy for the electromigration. Thus Cu thin films may be potentially good candidate for the next choice of advanced thin film interconnection materials where high current density and good EM resitance are required. Passivated Al thin films showed the increased MTF(Mean-time-to-Failure) values, that is, the increased EM resistance characteristics due to the dielectric passivation effects at the interface between the dielectric overlayer and the thin film interconnection materials.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.27.1-27.9
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• 2019

Background: Implants are becoming the first choice of rehabilitation for tooth loss. Even though they have a high success rate, failures still occur for many reasons. The objective of this study is to analyze the reasons for recurring failure at the same site and the results of re-implantation. Methods: Thirteen patients (11 males and 2 females, mean age 60 ± 9.9 years) who experienced implant surgery failure at the same site (same tooth extraction area) two or more times in the Department of Oral and Maxillofacial Surgery, Seoul National University Bundang Hospital, between 2004 and 2017 were selected. The medical records on a type, sites, diameter, and length of implants; time and estimated cause of failure; and radiographs were reviewed. Data were collected and analyzed retrospectively, and the current statuses were evaluated. Results: A total of 14 implants experienced failure in the same site more than two times. Twelve implants were placed in the maxilla, while 2 implants were placed in the mandible. The maxillary molar area was the most common site of failure (57.1%), followed by the mandibular molar, anterior maxilla, and premolar areas (14.3% each). The first failure occurred most commonly after prosthetic treatment (35.7%) with an average period of failure of 3.8 months after loading. Ten cases were treated as immediate re-implantation, while the other 4 were delayed reimplantation after an average of 3.9 months. The second failure occurred most commonly after prosthetic treatment (42.9%), with an average of 31 months after loading; during the healing period (42.9%); and during the ongoing prosthetic period (14.3%). In 3 cases (21.4%), the treatment plan was altered to an implant bridge, while the other 11 cases underwent another implant placement procedure (78.6%). Finally, a total of 9 implants (64.3%) survived, with an average functioning period of 60 months. Conclusions: Implants can fail repeatedly at the same site due to overloading, infection, and other unspecified reasons. The age and sex of the patient and the location of implant placement seem to be associated with recurring failure. Type of implant, bone augmentation, and bone materials used are less relevant.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.157-164
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• 2012

When designing a multifunctional system consisting of many components performing many functions or missions, it is important to determine the reliability, availability, and maintainability (RAM) of the system and components, and we consider system availability to be the optimization criterion. For given intervals of mean time between failure (MTBF) and mean time to repair (MTTR) of the components, we want to determine the values of MTBF and MTTR for all components that satisfy the target availability. A heuristic method is proposed for finding near-optimal solutions through simulation. We also study numerical examples to check effects of model parameters on the optimal solutions.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.3
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• pp.233-238
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• 2001

This paper deals with demand forecasting of parts in an automobile model which has been extinct. It is important to estimate how much inventory of each part in the extinct model should be stocked because production lines of some parts may be replaced by new ones although there is still demands for the model. Furthermore, in some countries, there is a strong regulation that the automobile manufacturing company should provide customers with auto parts for several years whenever they are requested. The major characteristic of automobile parts demand forecasting is that there exists a close correlation between the number of running cars and the demand of each part. In this sense, the total demand of each part in a year is determined by two factors, the total number of running cars in that year and the failure rate of the part. The total number of running cars in year k can be estimated sequentially by the amount of shipped cars and proportion of discarded cars in years 1, 2,$\cdots$, i. However, it is very difficult to estimate the failure rate of each part because available inter-failure time data is not complete. The failure rate is, therefore, determined so as to minimize the mean squared error between the estimated demand and the observed demand of a part in years 1, 2,$\cdots$, i. In this paper, data obtained from a Korean automobile manufacturing company are used to illustrate our model.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.13.1-13.6
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• 2020

Background: The aim of this study was to evaluate the factors that may affect implant fixture fractures. Methods: Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were included. Implant/crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, and the success and survival rate of the replaced implants were evaluated retrospectively. Results: Thirteen implants were fractured in 12 patients. Patient mean age at the time of fracture was 59.3 years. Of the 13 implants, 7 implants were placed at our hospital, and 6 were placed at a local clinic. The mean crown/implant ratio was 0.83:1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five implants, and the presence of peri-implant diseases in five implants. All the fractured implants were removed, and 12 out of the 13 sites were re-implanted. Parafunctions were observed in two patients: one with bruxism and one with attrition due to a strong chewing habit. Conclusions: Several clinical symptoms before the fracture of an implant can predict implant fixture failure. Therefore, if these clinical symptoms are observed, appropriate treatments can be taken before more serious complications result.

• Journal of Dental Anesthesia and Pain Medicine
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• v.17 no.4
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• pp.297-305
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• 2017

Background: Fiberoptic nasotracheal intubation (FNI) is performed if it is difficult to open the mouth or if intubation using laryngoscope is expected to be difficult. However, training is necessary because intubation performed by inexperienced operators leads to complications. Methods: Every resident performed intubation in 40 patients. Success of FNI was evaluated as the time of FNI. First intubation time was restricted to 2 min 30 s. If the second attempt was unsuccessful, it was considered a failed case, and a specialist performed nasotracheal intubation. If the general method of intubation was expected to be difficult, awake intubation was performed. The degree of nasal bleeding during intubation was also evaluated. Results: The mean age of the operators (11 men, 7 women) was 27.8 years. FNI was performed in a total of 716 patients. The success rate was 88.3% for the first attempt and 94.6% for the second attempt. The failure rate of intubation in anesthetized patients was 4.9%, and 13.6% in awake patients. When intubation was performed in anesthetized patients, the failure rate from the first to fifth trial was 9.6%, which decreased to 0.7% when the number of trials increased to > 30 times. In terms of awake intubation, there was no failed attempt when the resident had performed the FNI > 30 times. The number of FNIs performed and nasal bleeding were important factors influencing the failure rate. Conclusion: The success rate of FNI increased as the number of FNI performed by residents increased despite the nasal bleeding.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.25-30
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• 2004

This paper gives an assessment criteria and average failure lifetime prediction for power supply of electrodeless fluorescent lamp. The paper present electric appliance safety standard and performance standard for power supply of electrodeless fluorescent lamp. also, It presents the Failure Rate or Mean Time To Failure(MTTF) for power supply of electrodeless fluorescent lamp. We suggest the assessment criteria and improve methods of the reliability on the design basis for the electrodeless fluorescent system.