• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.5
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• pp.177-184
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• 2024

Concrete, the primary material used in quay walls, is directly exposed to saline environments. Coping concrete, particularly in areas where periodic berthing and loading/unloading occur, is prone to rapid quality deterioration. Current facility safety and maintenance guidelines assess concrete durability at specific points through sampling, which are intended to represent the entire inspection unit. This paper explores quality management strategies from an areal perspective by applying various non-destructive scanning methods to extensive areas of coping concrete. Ultrasonic array imaging and ground-penetrating radar scanning images revealed significant quality degradation in berthing operation areas, whereas sampling-based ultrasonic pulse velocity and rebound hardness values were less effective in detecting this degradation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.789-796
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• 2019

If the development of Integrated Logistics Support (ILS) for maintenance of the end step is conducted systematically and efficiently, the weapon system lifecycle can be postponed and the availability can be improved. DEFense CONdition (DEFCON) is maintained as perfect. Nevertheless, like its importance, the guide for maintaining the depot performance is applied differently for each weapon system. The errors that can result cause additional cost, etc. ILS development at depot level maintenance is different from full scale development. Therefore, this study distinguishes the management and deployment section for the development concept. An additional way to perform an efficient development of depot maintenance element when determining the depot maintenance period were presented. This study examined how the Reliability, Availability, Maintainability (RAM), Logistics Support Analysis (LSA), and ILS 11 elements intersect at the depot maintenance sources. An analytical study of concrete adoptable plans was performed. The systematic adoption of a development procedure can make it possible to calculate the adoptable development cost. In addition, it can be helpful for improving the quality level and practical use of work products.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.737-745
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• 2015

The purpose of this study is to clarify the challenges and suggest regulatory improvement strategy by investigating the Japanese building maintenance system which had been conducted for decades. The efficiency and problems of the current building maintenance system of Korea are analyzed by stake holders and purpose of management. The results show that several strategies are important to improve the quality of building maintenance. They include check list focusing on the purpose of maintenance, efficient and fair criteria, rational checking period considering owner's budget, cooperation with professionals in facilities, and promotion of professional companies participation. The results imply that the challenges should be solved systematically rather than individually.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.1-8
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• 2018

PURPOSES : Case studies of an asphalt-overlay project with a performance-based contract method were conducted on a national highway in Korea to evaluate the effect of the method on asphalt pavement maintenance. This study evaluated the procedure of the performance-based contract method. METHODS : In this study, an asphalt-pavement maintenance project for a national highway was assessed with a performance-based contract to investigate the advantage of the new contract procedures. This is the first trial applying the performance-based contract to a pavement-rehabilitation project in Korea. In the four case studies, the warranty period of the performance-based contract was designed for seven years. The research team monitored the construction site to compare the normal contract method with the performance-based contract method. The case studies' project sites were investigated after the end of the construction. RESULTS : Based on the limited case studies, the performance-based contract method could extend the service life of the asphalt pavement and reduce the pavement-maintenance budget because the quality control was well managed by the contractors. However, a few construction laws would be necessary to apply the performance-based contract method in the future. CONCLUSIONS : Using the performance-based contract, the construction company made great efforts to guarantee the warranty period and to apply the optimal maintenance method, based on the pavement distress condition. The contractor and the agency would need to understand the new performance-based contract system for it to be activated. Therefore, a proper education program for the performance-based contract system would be needed to educate the stakeholders regarding the procedures and their effects on the pavement management and maintenance.

• Water for future
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• v.24 no.1
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• pp.83-92
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• 1991

The purpose of this paper is to estimate river maintenance water of the main gauging stations in Geum river watershed. The estimation methods of river maintenance water are classified into two categories : views of supply and demand. The definition of river main-tenance water in this paper, is the maximum value between mean drought flow and environmental conserving flow. In order to estimate river maintenance water, the mean drought flow estimated at the upstream of the Daecheong Dam but the downstream of the Daecheong Dam estimated mean drought flow and water quality control flow use of QUAL2E Model. In result, a mean drought flow showed large value at the Gong ju and Gyu am station as the downstream of the Daecheong Dam. The river maintenance water is 33.82$m^3$/sec at the Gong ju station, 51.51$m^3$/sec at the Gyu am station. Therefore, an estimation of the river maintenance water in the Geum River watershed concluded suitability which is determined mean drought flow.

• The Transactions of the Korea Information Processing Society
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• v.1 no.3
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• pp.299-310
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• 1994

Re-engineering tools can substantially increase software maintenance productivity and the quality of maintenance work. Re-engineering usually involves changing the form(e.g.changining objects names and definitions, restructuring process logic) of a program. In this paper, we describe the design and implementation of InMaC＋＋ that is a software tool oriented towards maintenance of C＋＋ object oriented programs. With InMaC＋＋, programms can be displayed and edited in two forms : as the code and as the diagram InMaC＋＋ also contains transformations in both directions, i,e. from code to diagram and from diagram to skeletons of code. Hence, it is suitable for re-engineering and maintenance of existing code. Specially designed browsers implement the graphical interface. InMaC＋＋ contains a database that is based on a simple but effective data model of InMaC＋＋ programs. The model contains only four object classes and three relations, which makes the tool small, and easy to implement and use. A simple query language allows browsing through the database.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.1035-1040
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• 2024

South Korea has seen an increased demand for road maintenance, since they experienced a rapid industrialization in 1960-70s. Between 2019 and the end of 2022, the total national expenditure on road maintenance steadily rose from KRW 3.4 trillion to KRW 4.5 trillion. Roads, responsible for about 80% of the nation's transportation, significantly affect ride quality, safety and maintenance costs. Among the different perspectives, this study focuses on the prevalence of potholes. Over 24,000 pothole instances are reported on highways in the past five years, which raises concerns due to various direct and indirect effects on road maintenance and safety issues. Various methods, including vision-based, vibration-based, and 3D reconstruction-based techniques, have been proposed for pothole detection and inspection. Vision-based methods effectively count and measure pothole shapes but which are sensitive to lighting conditions. Vibration-based methods offer cost-effectiveness, although it may not provide precise pothole shape information. 3D reconstruction-based methods deliver accurate shape measurements, while it comes with higher costs. To establish an effective road maintenance system, prioritization criteria for potholes is required to be established and applied. These criteria may vary across countries or regions. For example, in the United States, potholes are classified based on depth into Low (<25mm deep), Moderate (25 to 50mm deep), and High (>50mm deep). In conclusion, this research addresses this research challenge of road damage and potholes in South Korea by exploring various pothole classification standards and utilizing advanced technology to develop an efficient road maintenance system. The outcome would benefit improved road infrastructure management and enhanced safety.

• Journal of Korean Society for Quality Management
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• v.28 no.3
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• pp.91-103
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• 2000

It is very important to rationally allocate manufacturing processes because customer's needs are being various, and product life cycle in the market Is being shortened. The process allocation is needed before making process control plan and is mostly being done by the field experience or intuition of machine operator, process engineer and/or maintenance technician. Therefore, a modified allocation method using the process variation is proposed. This paper presents the result of comparative studies between current method and the proposed one.

• Journal of Korean Society for Quality Management
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• v.28 no.3
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• pp.11-17
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• 2000

This paper presents a model for determining the optimal number of general repairs and supplementary input cost limit rate in addition to minimal repair cost rate to implement preventive maintenance. The basic concept parallels the periodic replacement model with minimal repair at failure introduced by Barlow and Hunter(1960) and Park(1979), only difference being the replacement signalled by the number of previous general repairs performed on the system. A general repair brings the state of the system to a certain better state than before repaired. Numerical examples are provided.

• Journal of Korean Society for Quality Management
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• v.14 no.1
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• pp.61-66
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• 1986

Many papers have suggested various models how to decide an optimal time for replacing equipment. In this study, Dynamic Programming is applied to establish a model of replacing equipment and a new algorithm is developed for computerization to meet the increased number of variables. It is possible to predict the real situation with higher accuracy by employing the proposed model including more variables such as planning horizon, original cost, salvage value, decreasing rate, operating and maintenance costs, increasing rate, and so on.