• Communications for Statistical Applications and Methods
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• v.17 no.6
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• pp.865-877
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• 2010

This paper considers the periodic preventive maintenance model for a repairable system following warranty expiration. We consider three types of warranty policies: free repair warranty, pro-rata repair warranty, and combination repair warranty. Under these preventive maintenance models, we derive the expressions for the expected cycle length, the total expected cost, and the expected cost rate per unit time. In addition, we explain 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 a Weibull distribution case.

• Journal of architectural history
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• v.28 no.3
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• pp.29-44
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• 2019

A major performance stage carpenter, Jang Insang led performance stages from the 1719 Sukjong Royal Banquet and was confirmed by historical records to be the first craftsman. Lee Wandeuk led the Hwaseong Fortress performance stages of the Jeongjo period and Gichuk Jinchan performance stages of the Sunjo period. The carpenter techniques he used during the Jeongjo period were succeeded to the Sunjo period. Ahn Sungil was the head craftsman who led the performance stages of Jagyeongjeon Jinjak, Muja Jinjak, and Gichuk Jinchan of the Sujo period, under which the foundation for court palace performances was laid. The progression of major carpenters includes Jang Insang of the Sukjong period, Jeon Yoochu of the Yeongjo period, Ahn Sugil of the Sunjo period, Yoon Seoksin of the Heonjong period, Kim Yoonsik of the Gojong period, Lee Jongyoon, Kim Soongil, Seo Sangmook, and Han Sujoon. In addition, the Major Repair of Injeongjeon Hall (1857) of the Cheoljong period was the most important palace construction project for transferring the carpenters' skills. Through this project, Ahn Sungil of the Sunjo period, Kim Myeonggap, Yoon Seoksin of the Heonjong period, Kwon Deuknyang, and Kim Sungil of the Gojong period were able to interact with each other. That is, this major repair project of Injeongjeon Hall reflected the major carpenters' best techniques through performance stage construction, showing the progression of Ahn Sungil, Yoon Seokshin, and Kim Sungil, who led the constructions of Gichuk Jinchan of the Sunjo period (1829), Mushin Jinchan of the Heonjong period (1848), and Jeonghae Jinchan of the Gojong period (1887), the most impressive performance stages of the late Joseon period. The carpenters of the court performance stages participated in important construction projects of the royal palace, reflecting the superior technical skills of the carpenters in the construction of court palace performance stages. The carpenters who played a leading role in the construction of performance stages were able to interact with one another and transfer their excellent technical skills, providing the driving force that allowed court performance stages to blossom into splendid and high-quality court stages in the late Joseon Dynasty.

• Clinics in Shoulder and Elbow
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• v.15 no.2
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• pp.99-108
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• 2012

Purpose: To evaluate the clinical results of arthroscopic repair with UU-Tension Band suture for full thickness rotator cuff tear above 4 cm sized. Materials and Methods: From January 2006 to October 2011, in 71 full thickness tears above 4 cm sized which is possible to arthroscopic repair to medial margin of greater tuberosity. The group I is 71 patients which is arthroscopic repair with UU-Tension Band suture, and the group II is 20 cases which is arthroscopic repair with simple suture. Both groups were compared with a VAS score for pain, Activity of Daily Living, UCLA score, KSS score in pre operation, 7 months, 1 year and last follow-up. Statistical analysis was performed by student t test and paired t est. Mean age was 63.2 (52~80) year old, mean follow-up was 38.4 (13~62) months. Results: The VAS scores for pain decreased from 8.1 at preoperative period to 1.6 at postoperative last follow-up period in group I (p<0.05), the score decreased from 7.6 at preoperative period to 1.8 postoperative last follow-up period in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). Mean ADL scores increased from 12.5 at preoperative period to 29.0 post operative last follow-up period in group I (p<0.05), the score increased from 11.3 in pre op to 27.5 post-operative last follow-up in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). The UCLA score increased from 12.9 at preoperative period to 28.7 postoperative last follow-up period in group I (p<0.05), the score increased from 13.8 at preoperative period to 30.1 postoperative last follow-up period in group II (p<0.05). The significant difference was not noted between two groups (p<0.05). In comparing of retear which was checked by MRI and ultrasound evaluated at postoperative period 7 months (mean: 27.5 weeks), the retears were 28% in the group I, and 11 shoulders out of 20 shoulders in the group II. The significant differences were noted between two groups (p<0.05). Conclusion: Arthroscopic repair with UU-Tension Band suture and simple suture for full thickness rotator cuff tear above 4 cm sized were not different clinical result between both groups. However, the significant differences were noted in point of failure rate between both groups.

• Clinics in Shoulder and Elbow
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• v.9 no.1
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• pp.20-26
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• 2006

Purpose: To evaluate the usefulness and functional results of open repair of massive rotator cuff tears combined with or without the tenoplasty of biceps long head. Materials and Methods: From March 2003 to August 2004, we evaluated 18 cases of the patient treated with open repair of massive rotator cuff tears. The mean age was 56 years and mean follow-up period was 15 months. We performed open repair of massive rotator cuff tears by tendon to bone repair, but in irrepairable 4 cases for tendon to bone repair performed open repair combined with tenoplasty of biceps long head. The functional results were assessed using the Constant score, the parameters of which were pain, dialy activity, mobility, strength and satisfaction. Results: The functional results were excellent in 4 cases, good in 8 cases, fair in 3 cases and poor in 3 cases. And the results of open repair combined with tenoplasty of biceps long head were good in 2 cases and fair in 2 cases. Re-repair was done in 1 case for re-rupture. And the functional result of this case was fair. The 3 poor cases were suspected re-rupture, the factor of which old age and weakened rotator cuff. It was impossible to do re-repair. Conclusion: The open repair combined with or without tenoplasty of biceps long head is a useful and effective method for massive rotator cuff tear.

• Advances in pediatric surgery
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• v.14 no.1
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• pp.21-26
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• 2008

There is significant morbidity and mortality associated with the combination of esophageal atresia (EA) and duodenal atresia (DA). Nevertheless, the management protocol for the combined anomalies is not well defined. The aim of this study is to review our experience with the combined anomalies of EA and DA. From May 1989 to August 2006, seven neonates were diagnosed as EA with DA at Asan Medical Center. In all cases, the type of EA was proximal EA and distal tracheoesophageal fistula (TEF). The diagnosis of DA was made in theprenatal period in 1, at birth in 4, 4 days after birth in 1 (2 days after EA repair) and at postmortem autopsy in 1. Except the one case where DA was missed initially, primary simultaneous repair was attempted. DA repair with gastrostomy followed by EA repair in 2, EA repair followed by DA repair without gastrostomy in 2, and TEF ligation followed by DA repair with gastrostomy in 1. There were two deaths. One baby had a large posterolateral diaphragmatic hernia, and operative repair was not attempted. The other infant who had a TEF ligation and DA repair with gastrostomy expired from cardiac failure due to a large patent ductus arteriosus. Simultaneous repair of EA and DA appears to be an acceptable management approach for the combined anomalies, but more experience would be required for the selection of the primary repair of both anomalies.

• Journal of architectural history
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• v.32 no.2
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• pp.7-19
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• 2023

This article focuses on the Namdaemum repair and the Seokguram restoration, which had begun in 1961, as an important repair conducted during the time of seeking the conservation principle of architectural heritage after liberation in Korea. Through the analysis of the principles described in the repair report issued after the two repairs, meeting records, and related expert announcements, it is shown that the principle of 'preservation of the historic state' had been established at Namdaemun repair and later have changed to the principle of 'restoration of the historic form' which means reconstruction in Seokguram restoration. By analyzing the minutes of the Cultural Heritage Committee's meeting on the repair of other cultural properties during this period, it is revealed that the key terms related to the preservation principle, 'historic form' and 'restoration', were given meaning as 'object' and 'method' of preservation, and then 'restoration of the historic form' has been gradually used as a conservation principle.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.349-356
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• 2006

At present, the selecting system and analytic estimation criterion on repair materials and methods of the deteriorated RC structures have not yet been set up in domestic. Under these circumstances, deterioration such as shrinkage crack, corrosion of rebar has been often occurred after repair, and this finally results in too frequent repairs. In this study, three types of repair methods were experimentally investigated by the accelerating test in a combined deterioration chamber and long-term field exposure test. Three types of repair methods applied in this study belong to a group of polymer cement mortar, which is commonly used in repair works. According to the results of this study, durability of repair mortar layers and corrosion properties of recovered rebar could be investigated in short period by the accelerating test in a combined deterioration chamber, which can simulate the condition of repeated high-and-low temperature and repeated dry-and-wet environment, spraying chloride solution and emitting $CO_2$ gas. After 36 month long-term filed exposure test in the coastal area, harmful macro-cracks are observed in the polymer cement mortar layer of some repair methods. These crack are considered to result from drying shrinkage of polymer cement mortar. Also, after 36 month exposure, amount of corrosion area and weight loss of rebar are found to be different according to the types of repair methods.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.209-217
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• 2013

The execution of a construction project involves the engagement of many participants. Generally, the Authority uses CM to certify that the Work is built according to the contract documents. The CM work scope is expressed in the Construction Technology Management Act and its Regulation. The mandated and delegated CM services are limited to the construction period. If Contractor is required to repair a construction defect, the Contractor should bear the burden of the inspection service for the defect repair, because it is associated with him. Nevertheless, CM should submit a bond to provide the inspection and supervision service for the defect repair. These may result in conflict with each liability. Therefore, CM service in the law and regulation was investigated and analyzed in this study to classify the characteristics of CM contracts, and it was suggested that the CM liability for the inspection and supervision service for the defect repair should be reconsidered.

• Journal of Korean Society for Quality Management
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• v.25 no.3
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• pp.86-95
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• 1997

This paper considers a repairable system, which is maintained preventively at periodic times and is minimally repaired at each failure. Most preventive maintenance policies for such repairable systems assume that the cost of minimal repair is constant regardless of its age at failure. However, it is more practical to consider the situations where the cost of minimal repair is dependent not only on its age at failue, but also on the number of preventive maintenance carried out prior to its failure. We consider the preventive maintenance carried out prior to its failure. We consider the preventive maintenance policy with age-dependent minimal repair cost. The optimal policies which minimize the expected cost rate over an infinite time span are discussed. We obtain the optimal period and number of preventive maintenance prior to replacement of the system.

• 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.