• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.185-192
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• 2003

In this paper, the properties on the optimal replacement policies for the general failure model are developed. In the general failure model, two types of system failures may occur : one is Type I failure (minor failure) which can be removed by a minimal repair and the other, Type II failure (catastrophic failure) which can be removed only by complete repair. It is assumed that, when the unit fails, Type I failure occurs with probability 1-p and Type II failure occurs with probability p, $0\leqp\leq1$. Under the model, the system is minimally repaired for each Type I failure, and it is repaired completely at the time of the Type II failure or at its age T, whichever occurs first. We further assume that the repair times are non-negligible. It is assumed that the minimal repair times in a renewal cycle consist of a strictly increasing geometric process. Under this model, we study the properties on the optimal replacement policy minimizing the long-run average cost per unit time.

• Journal of Applied Reliability
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• v.14 no.2
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• pp.122-128
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• 2014

In this paper, we consider the periodic preventive maintenance model for a repairable system following the expiration of extended warranty under replacement-repair warranty. Under the replacement-repair warranty, the failed system is replaced or minimally repaired by the manufacturer at no cost to the user. Also, under extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user during the original extended warranty period. As a criterion of the optimality, we utilize the expected cost rate per unit time during the life cycle from the user's perspective. And then we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.11a
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• pp.37-40
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• 2003

This present paper mainly contains adhesion part disconnection type exposure composition waterproof method using embossing PVC sheet. The existing polymer resin coating and sheet waterproofing construction method have, however, some weak point such as being decrease life cycle of concrete with water leaking from materials be affected by crack and movement dash bond concrete through the whole-adhere construction. Above the reason, this paper has particular method increasing crack-defending performance from stress occurred concrete movement by part disconnection, adds maintain waterproofing performance subordinate sheet, that can be contributed a convenience of maintenance which is decreasing industrial waste and repair construction cycle through the part repair in case of leaking water.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.37-40
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• 2003

This present paper mainly contains adhesion part disconnection type exposure composition waterproof method using embossing PVC sheet. The existing polymer resin coating and sheet waterproofing construction method have, however, some weak point such as being decrease life cycle of concrete with water leaking from materials be affected by crack and movement dash bond concrete through the whole-adhere construction. Above the reason, this paper has particular method increasing crack-defending performance from stress occurred concrete movement by part disconnection, adds maintain waterproofing performance subordinate sheet, that can be contributed a convenience of maintenance which is decreasing industrial waste and repair construction cycle through the part repair in case of leaking water.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.551-556
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• 2004

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The life-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Journal of Microbiology
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• v.39 no.2
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• pp.102-108
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• 2001

DNA damage response has a central role in the maintenance of genomic integrity while mutations in related genes may result in a range of disorders including neoplasic formations. The uvsZl characterized in this report is a navel uvs mutation in Aspergillus nidulans, resulting in a nucleotide excision repair (NER) phenotype: UV-sensitivity before DNA synthesis (quiescent cells), high UV-induced mutation frequency and probable absence of involvement with mitotic and meiotic recombinations. The mutation is recessive and nan-allelic to the previously characterized uvsA101 mutation, also located on the paba-y interval on chromosome I. uvsZl skewed wild-type sensitivity to MMS, which suggests non-involvement of this mutation with BER. Epitasis tests showed that the uvsZ gene product is probably involved in the same repair pathways as UVSB or UVSH proteins. Although mutations in these proteins result in an NER phenotype, UVSB is related with cell cycle control and UVSH is associated with the post-replicational repair pathway. The epistatic interaction among uvsZl and uvsB413 and uvsH77 mutations indicates that different repair systems may be related with the common steps of DNA damage response in Aspergillus nidulans.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.984-997
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• 2021

This study sought to evaluate DNA damage and repair in porcine postovulatory aged oocytes. The DNA damage response, which was assessed by H2A.X expression, increased in porcine aged oocytes over time. However, the aged oocytes exhibited a significant decrease in the expression of RAD51, which reflects the DNA damage repair capacity. Further experiments suggested that the DNA repair ability was suppressed by the downregulation of genes involved in the homologous recombination (HR) and nonhomologous end-joining (NHEJ) pathways. The expression levels of the cell cycle checkpoint genes, CHEK1 and CHEK2, were upregulated in porcine aged oocytes in response to induced DNA damage. Immunofluorescence results revealed that the expression level of H3K79me2 was significantly lower in porcine aged oocytes than in control oocytes. In addition, embryo quality was significantly reduced in aged oocytes, as assessed by measuring the cell proliferation capacity. Our results provide evidence that DNA damage is increased and the DNA repair ability is suppressed in porcine aged oocytes. These findings increase our understanding of the events that occur during postovulatory oocyte aging.

• International Journal of Reliability and Applications
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• v.12 no.1
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• pp.41-48
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• 2011

This paper considers the maintenance model suggested by Jung and Park (2010) to adopt the Bayesian approach and obtain an optimal replacement policy following the expiration of NFRRW. As the criteria to determine the optimal maintenance period, we use the expected cost during the life cycle of the system. When the failure times are assumed to follow a Weibull distribution with unknown parameters, we propose an optimal maintenance policy based on the Bayesian approach. Also, we describe the revision of uncertainty about parameters in the light of data observed. Some numerical examples are presented for illustrative purpose.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.27-30
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• 2011

Analysis data of basics which are used for LCC(Life Cycle Cost) analysis of buildings and maintenance plan, are demanded to secure according as replacement cycle of repairs of apartment houses has come. However, investigation techniques and systems for investigating condition of deterioration of apartment houses, have not been made yet in Korea. For this reason, this study was wanted to make investigation techniques and systems, so the process for maintenance of apartment houses was researched and the required quality and deterioration factors of interior/exterior materials were investigated. As a result Check-List for investigating condition of deterioration, was made. if this is used during a nonscheduled, a routine, a regular and a urgency check, the methodical investigation will be achieved. Furthermore, if this is used for maintenance of apartment houses, it will be helped to select the repair cycle and the long-term repair plan.

• BMB Reports
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• v.56 no.5
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• pp.265-274
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• 2023

Defects in DNA double-strand break (DSB) repair signaling permit cancer cells to accumulate genomic alterations that confer their aggressive phenotype. Nevertheless, tumors depend on residual DNA repair abilities to survive the DNA damage induced by genotoxic stress. This is why only isolated DNA repair signaling is inactivated in cancer cells. DNA DSB repair signaling contributes to general mechanism for various types of lesions in diverse cell cycle phases. DNA DSB repair genes are frequently mutated and amplified in cancer; however, limited data exist regarding the overall genomic prospect and functional result of these modifications. We list the DNA repair genes and related E3 ligases. Mutation and expression frequencies of these genes were analyzed in COSMIC and TCGA. The 11 genes with a high frequency of mutation differed between cancers, and mutations in many DNA DSB repair E3 ligase genes were related to a higher total mutation burden. DNA DSB repair E3 ligase genes are involved in tumor suppressive or oncogenic functions, such as RNF168 and FBXW7, by assisting the functionality of these genomic alterations. DNA damage response-related E3 ligases, such as RNF168, FBXW7, and HERC2, were generated with more than 10% mutation in several cancer cells. This study provides a broad list of candidate genes as potential biomarkers for genomic instability and novel therapeutic targets in cancer. As a DSB related proteins considerably appear the possibilities for targeting DNA repair defective tumors or hyperactive DNA repair tumors. Based on recent research, we describe the relationship between unstable DSB repairs and DSB-related E3 ligases.