• Journal of the Korea Society of Computer and Information
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• v.9 no.2
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• pp.63-68
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• 2004

In this study We designed development and operation of computer maintenance & repair system which is efficient and systematic on the disorder of PC in the places with many computers such as company, public organization, school, etc. We designed so as to clearly measure and manage the service level by using SLA(Service Level Agreement) technique which is being used actively in network maintenance & repair contract And We designed system which can provide One Stop Service so that the whole process of service including service demand point, maintenance & repair activity, user's satisfaction.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.2
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• pp.141-152
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• 2006

This paper presents the development of a decision model to examine the optimal repair action for a deteriorating system. In order to make a reasonable decision, it is necessary to perform an analysis of the uncertainties embedded in deterioration and to evaluate the repair actions based on the expected future cost. Focusing on the power law failure model, the uncertainties related to deterioration are analyzed based on the Bayesian approach. In addition, we develop a decision model for the optimal repair action by applying a repair cost function. A case study is given to illustrate a decision-making process by analyzing the loss incurred due to deterioration.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.2
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• pp.273-281
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• 2007

The decision of how long performing system burn-in must be answered with a probabilistic model of a system lifetime at which infant mortality failures created during assembly processes are quantified. In this paper, we propose such a model which is modified from previous results. Using the system model, we derived system reliability in terms of component and system burn-in times for the two cases of minimal repair at system failure and of component replacement and connection repair at their failure times. The procedure is illustrated with a bridge system and the optimal system burn-in times are obtained for maximizing system reliability. The result suggests that an assumption of minimal repair at system failure may underestimate the optimal burn-in time in practice.

• KSCI Review
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• v.12 no.1
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• pp.21-27
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• 2004

In this study We designed development and operation of computer maintenance & repair system which is efficient and systematic on the disorder of PC in the places with many computers such as company, public organization. school, etc. We designed so as to clearly measure and manage the service level by using SLA(Service Level Agreement) technique which is being used actively in network maintenance & repair contract. And We designed system which can provide One Stop Service so that the whole process of service including service demand point, maintenance & repair activity, user's satisfaction.

• Structural Monitoring and Maintenance
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• v.2 no.2
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• pp.133-143
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• 2015

Civil engineering infrastructure is aging and requires cost-effective maintenance strategies to enable infrastructure systems operate reliably and sustainably. This paper presents an approach for determining risk-cost balanced repair strategy of corrosion damaged reinforced concrete structures with consideration of uncertainty in structural resistance deterioration. On the basis of analytical models of cover concrete cracking evolution and bond strength degradation due to reinforcement corrosion, the effect of reinforcement corrosion on residual load carrying capacity of corroded reinforced concrete structures is investigated. A stochastic deterioration model based on gamma process is adopted to evaluate the probability of failure of structural bearing capacity over the lifetime. Optimal repair planning and maintenance strategies during the service life are determined by balancing the cost for maintenance and the risk of structural failure. The method proposed in this study is then demonstrated by numerical investigations for a concrete structure subjected to reinforcement corrosion. The obtained results show that the proposed method can provide a risk cost optimised repair schedule during the service life of corroded concrete structures.

• Journal of the Korean Society for Railway
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• v.10 no.3 s.40
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• pp.306-312
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• 2007

This paper presents the optimal design method of the train repair facility based on the simulation analysis. The train is divided into the power car, motorized car and passenger car for the simulation process analysis and train repair facility is composed of each subsystems such as a blast, dry and wash workshop. In simulation analysis, we consider the critical (dependent) factors and design (independent) factors for the optimal design. Therefore, a simulation optimization uses Evolution Strategy (ES) in order to find the optimal design factors. Experimental results indicate that simulation design factors are sufficient to satisfy the conditions of dependent variables. The proposed analysis method demonstrates that simulation design factors determined by the simulation optimization are appropriate for real design factors in a real situation and the accuracy and confidence for the simulation results are increased.

• Clinical Pain
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• v.19 no.2
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• pp.59-63
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• 2020

Rotator cuff tear is often cited as a reason for shoulder pain and dysfunction in patients > 40 years of age. Surgical repair of rotator cuff tear is one of the most commonly performed orthopedic surgical procedures. Until now, the success rate of surgical repair for rotator cuff tear has not been satisfactory. Many factors influence the process of rotator cuff repair such as the presence of tendinosis and fatty infiltration, but the main factor is the difficulty in achieving healing at the tendon to bone interface. There is a clinical need for bioengineering approaches to promote regeneration of the native enthesis and reduce the poor outcomes after surgical repair. Toward this end, the design and fabrication of multiphasic or hierarchically structured scaffolds have received great attention. This manuscript deals with information on the tendon to bone interface and tries to find out why a multiphasic scaffold is necessary to reproduce it and considerations that need to be taken into to make an ideal scaffold.

• International Journal of Korean Welding Society
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• v.2 no.2
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• pp.1-6
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• 2002

This article presents an integrated modeling approach for coupled analysis of heat transfer and microstructure evolution in welding carbon steel. The modeling procedure utilizes commercial finite element code ABAQUS/Standard as the platform for solving the equation of heat conduction. User subroutines that Implement computational thermodynamics and kinetics models are integrated with the FEA code to compute the transient microstructure evolution. In this study, the integrated models are applied to simulate the hot-tap repair welding of carbon steel pipeline. Microstructural components are treated as user output variables. Based on the predicted microstructure and cooling rates, hardness distributions in the welds were also predicted. The predicted microstructure and hardness distribution were found in good agreement with metallographic examinations and hardness measurements. This study demonstrates the applicability of computational models for the development of welding procedure for in-service pipeline repair.

• Journal of architectural history
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• v.23 no.1
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• pp.7-19
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• 2014

This study considers the proper repair techniques by examining the most representative repair cases of the Korean arch bridges and proposes the constructional manual which can apply similar occasions. The cases are Seonamsa Seungseongyo and Songgwangsa Geukrockgyo where this researcher had taken part in the repair works. This Study proposes the maintenance construction manual about the performance degradation drew by performance degradation of the both Korean arch bridges in the maintenance process. First, arch bridge maintenance should be carried out in the dry season, when water is impermeable in the bottom surface of the bridge. Moreover, risk factors of the maintenance should be excluded to secure the water vally flow, the bypass and the temporary bridge. Second, prior to repair, it has to precede (1)3D shooting (2)formal examination (3)structure safety test (4)geological and lithic surveys (5)arch curvature establishment and makeshift frame settlement before transformation (6)relationship expert comments. Third, if the baduk and the foundation stones are inevitable to replace due to performance degradation on the foundation, it should use the high quality stones and secure greater stress by extending the standard range. The foundation on irregular rock needs to be flattened and underside on the replaced materials require Grengyijil to deliver the equal loads. Fourth, In the process of dismantling the stones of the arched bridge, it could make heavy weathering degree and not reuse the materials. Charge should converge the expert advices to choose the reuseable, the conservate and the alternative materials, and increase the reutilization of the raw materials by preservation and reinforcement treatments. Fifth, the side wall should be repaired by the rubble work technique which is not able to pile compost satiety, so it must use long depth of masonary stones for reinforcement. It is considered to reinforce the stone wall in shore as much as possible and protect the abutment and the side wall on the upstream for the arch bridge maintenance works.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.4
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• pp.216-231
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• 2001

Several methods for improving device yields and characteristics have been studied by IC manufacturers, as the options for programming components become diversified through the introduction of novel processes. Especially, the sequential repair steps on wafer level and package level are essentially required in DRAMs to improve the yield. Several repair methods for DRAMs are reviewed in this paper. They include the optical methods (laser-fuse, laser-antifuse) and the electrical methods (electrical-fuse, ONO-antifuse). Theses methods can also be categorized into the wafer-level(on wafer) and the package-level(post-package) repair methods. Although the wafer-level laser-fuse repair method is the most widely used up to now, the package-level antifuse repair method is becoming an essential auxiliary technique for its advantage in terms of cost and design efficiency. The advantages of the package-level antifuse method are discussed in this paper with the measured data of manufactured devices. With devices based on several processes, it was verified that the antifuse repair method can improve the net yield by more than 2%~3%. Finally, as an illustration of the usefulness of the package-level antifuse repair method, the repair method was applied to the replica delay circuit of DLL to get the decrease of clock skew from 55ps to 9ps.