• Journal of the Korean Statistical Society
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• v.28 no.4
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• pp.515-522
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• 1999

A repair process of a system consisting of both perfect repairs and minimal repairs is introduced. The type of repair, when the system fails, is determined by an embedded two state Markov chain. We study several stochastic properties of the process including the preservation of ageing properties and the monotonicities of the time between successive repairs. After assigning repair costs to the process, we also show that an optimal repair policy uniquely exists, if the underlying life distribution of the system has DMRL.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.21-33
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• 2014

PURPOSES: The purpose of this study was to break away from the workforce method using cold-mix asphalt mixtures and has a constant quality and has develop repair materials of pre-production asphalt-precast types. METHODS: The selection of the repair material was determined as the results obtained through physical properties of materials and the field applicability. In case of repair materials, values obtained through Marshall stability test & the dynamic stability test & retained stability test as well as the site conditions was considered. In case of adhesive, test results were obtained through examination of the bond strength(tensile, shear) and the field applicability of the adhesive was examined through combined specimens to simulate field applications. RESULTS : According to the results of laboratory tests, in the case of repair materials, Marshall stability and dynamic stability, retained stability of cold-mix reaction type asphalt mixture is the highest. In the case of adhesive, two-component epoxy-urea has a very high bonding strength(tensile, shear) was most excellent. According to the results of field tests, when epoxy-urea was excellent workability. Also, the repair body through actual mock-up test did not occur large deformation and fracture after 12 months. CONCLUSIONS : A suitable repair material is cold-mix reaction type mixture of asphalt-precast, a suitable adhesive is a two-component epoxy-urea.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.4
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• pp.341-348
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• 2005

This paper is concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it with a new item. In this paper, we consider repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.14-19
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• 2010

Purpose: The purpose of this study was to compare clinical outcomes between the new V-shaped repair method and conventional methods for the arthroscopic repair of Type II SLAP lesions. Materials and Methods: Our study population consisted of 23 people treated with the new V-shaped repair method or conventional methods in the arthroscopic repair of Type II SLAP lesions at our institution between May 2006 and October 2008. Eleven shoulders were treated using the new V-shaped repair method. Twelve shoulders were treated using conventional methods. The average follow up period was 15 months. For evaluation of clinical results, we used UCLA and VAS pain scores. Results: Comparing change scores (preoperative vs. postoperative states) there were no significant differences in UCLA score or VAS score between the two groups. Conclusion: The new V-shaped repair technique elicits similar clinical results with conventional arthroscopic repair techniques and thus can be considered a useful alternative when using an absorbable suture that is anchor linked with only one suture.

• Journal of Chest Surgery
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• v.16 no.4
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• pp.476-484
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• 1983

Ventricular septal defect[VSD] associated with aortic regurgitation[AR] represents 2 to 7.5% of all VSD which is most common congenital heart disease. The aortic valve may by normal in infants with VSD, but the aortic regurgitation may be developed in these patients later. The aortic valve became fibrotic, thickened, deformed and prolapsed, so these late deformities require to be corrected with plication, valvuloplasty or aortic valve replacement [AVR]. There are some controversy between the early repair of VSD alone and the late repair of VSD and aortic valve till now. From December 1971 to August 1983, we had experienced 24 patients of VSD associated with AR which constitute 6.5% of our total patients with VSD. The VSD was subpulmoary [type I] in 14[58.3%], subcristal [type II] in 8[33.3%], atrioventricular canal type[type III] in 1, and combine of type I and II in 1. Patch repair of VSD was made in 15 patients and direct suture of small VSD in 9.14 patients had aortic plication of valvuloplasty and 9 had AVR accompanying VSD repair, and 1 patient had VSD closure alone. The postoperative courses of these patients were uneventful except in some cases. A patient who was undertaken AVR with Starr-Edwards ball valve and VSD closure, died due to left ventricular failure and low cardiac output syndrome. Follow up shows, in 14 patients with aortic plication or valvuloplasty, AR was developed in 9. In 9 AVR, there were two later complications which were paravalvular leakage in one and re-AVR due to subacute bacterial endocarditis in another.

• Journal of Korean Society of Rural Planning
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• v.18 no.3
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• pp.67-76
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• 2012

The purpose of this study is to analyze the landscape preference and landscape images of the Agricultural Aqueduct Bridges(AAB) by several different criteria. Semantic Differential Scale(SD scale) with landscape adjectives and landscape preference are used to estimate the alternatives of the AAB. The statistic methods such as descriptive analysis, t-test, factor analysis and regression, cluster analysis, are operated. The landscape preference of the alternatives is generally positive, 3.977 out of 7.000. The gate type is the most preferred, but the road-along type is the worst, by the location types. The simple repair type is the worst preferred, but total remodeling is the most, by the repair types. The characteristics of the AAB are analyzed and 4 factors of visual landscape are contracted; interest, orderliness, naturality and spatiality. Cumulative factor loading of these factors is about 65%, which is quite high. The higher and bigger AAB's are preferred, and the advanced finishing materials are also preferred, such as aluminum or wood panels. The long span is also preferred and the high repair cost would be preferred. But in this study, the cost-benefit analysis is not included, so it is recommended to research further, considering the cost variable with the visual factors.

• Journal of Chest Surgery
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• v.21 no.4
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• pp.665-671
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• 1988

Between 1981 and 1987, five patients with an interruption of the aortic arch were operated upon. All had a ventricular septal defect and a patent ductus arteriosus as associated anomalies. A two-stage procedure was employed in these cases, the initial procedure being repair of the interrupted arch, ligation of the patent ductus arteriosus, banding of the main pulmonary artery and a lung biopsy which was followed, 5 to 49 months later, by the repair of the ventricular septal defect. Four patients completed the two-stage procedure with one postoperative mortality. The remaining patient is yet to complete the second stage procedure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.140-141
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• 2017

This study is based on the evaluation of a single component injection type adhesive repair material and a new 2 component type used in leakage of underground concrete structures. The studies showed that based on different mix ratio of the 2 component type adhesive sealant comprised of an asphalt main and latex mixture agent the viscosity of the material compound differed significantly. Based on a permeability testing, injection and economic efficiency, and performance, the appropriate ratio was determined to be 6:1 and was proceeded to the KS F 4935 evaluation method. The 2 component type adhesive sealant uses a static mixer and a cartridge type container for the injection procedure and was able to satisfy the evaluation criteria outlined in the KS F 4935 standard.

• Journal of the military operations research society of Korea
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• v.25 no.2
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• pp.144-157
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• 1999

In this paper, we consider a new preventive replacement policy for the system which deteriorates while it is in operation with an increasing failure rate. The system is subject to two types of failure. A type 1 failure is repairable while a type 2 failure is not repairable. In the new policy, a system is replaced at the age of $t_p$ or at the instant the$\textsc{k}^{th}$ type 1 failure occurs, whichever comes first. However, if a type 2 failure occurs before a preventive replacement is performed, a failure replacement should be made. We assume that a type 1 failure can be rectified with a minimal repair. We also assume that a replacement takes a non-negligible amount of time while a minimal repair takes a negligible amount of time. Under a cost structure which includes a preventive replacement cost, a failure replacement cost and a minimal repair cost, we develop a model to find the optimal ($\textsc{k},t_p$) policy which minimizes the expected cost per unit time in the long run while satisfying a system availability constraint.

• Korean Journal of Microbiology
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• v.26 no.2
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• pp.113-121
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• 1988

Ozone, an atmospheric pollutant, can damage similar UV and X-rays DNA and its components. It is possible then that the KNA damage produced by this gas are similar, to some extent, to those of radiations and that they could be repaired by the same DNA repair mechanisms. It has been observed in Escherichia coli that radiosensitive strains such as lex A, rec A and pol A, all deficient to some extent for DNA repair, are more sensitive to ozone than a wild type strain. We have thendetermined the ozone resistance and host-cell reactivation of ozone-damaged T3 phages for the E. coli double mutants pol A, lex A, uvr B, lex A, uvr A, rec A and rec A lox A. According to the results, the DNA polymerase 1 plays a key role in ozone resistance and Type 11 mechanism and/or shory patch excision repair are the most important for it. The interactions between the different DNA repair mechanisms are secondary. There is a strong correlation between ozone resistance and the capacity to reactivate T3 phages damaged by ozone.