• Journal of the Korean Society for Railway
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• v.7 no.3
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• pp.223-231
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• 2004

The accumulated BMS data have made it easy to make reasonable decision-making for bride maintenance and repair work. In the developing period of BMS, the bridge management was not easy due to the lack of understanding of BMS and low credibility of the data. In recent years, it has been possible to enhance the credibility of the data and to expand the application scopes of BMS with the efforts of Local Road Construction Offices. The reasonable decision making for bridge management can improve the performance of bridges under the practical constraints such as limited budget. It can then result in the reduction of bridge maintenance budget. This study provides the methodology for the application of mobile internet-based KOBMS for bridge management. The data flow for BMS is the most important factor for decision-making on budget allocation, and this study establishes the basic scheme of the data flow for BMS. The implementation of PDA for BMS may suggest a new paradigm of 'Mobile' in the field of construction management.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.121-128
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• 1999

In this study, the behavior of R/C beams strengthened with carbon fiber laminate (CFL) is analyzed from the test results. CFL is attractive for this application due to its good tensile strength and low weight. Test parameters are the width and the thickness of CFL and repair of damaged specimen. The failure mode and ultimate load are analyzed from these measured data. Test results show that the peak load of specimens strengthened with CFL is increased to 1.27~2.04 times that of non-rehabilitation specimen. The wider lap width, larger amount of CFL, the larger strength is obtained. But the ductile behavior of the rehabilitated specimens is inversely proportional to the CFL thickness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.1
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• pp.107-112
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• 1997

A series of reinforced concrete beams was tested to evaluate the flexural performance of the repaired RC beams. The key parameters for this study were the size and location of the patch, and the repair materials, including polymer, polymer-cementitious and cementitious materials. The repaired specimens failed by a typical flexural mode with minor interfacial bond failure. Beams repaired with polymer, polymer-cementitious and cementitious materials recover 100%, 91%, and 97% of the flexural strength respectively, while beams with cement mortar lose approximately 30% of the strength. Compared with the pressure injection techniques the specimens repaired with patching techniques show low flexural strength, with significant interfacial bond failure. Location and size of the repaired part do not affect the recovering performance. Interfacial behavior between repair and strengthening materials is the major influencing factor for the composite structures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.1-7
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• 2004

The purpose of the study is to review current status of green roof technology and to suggest the issues and solutions related with the technological problems of green roof in Korea. The scope of the study is limited to the extensive green roof which requires low maintenance. Technological issues related with green roof include soil, water proofing, water drain, vegetation and maintenance. Several solutions to invigorate green roof technology were suggested as follows; 1)implementation of technical standard for green roof and technology certification system, 2) development of suitable raw materials for green roof, 3) construction guidelines and uniform construction specification, 4) formulation of city ordinance for green roof, and 5) exchange program with foreign green roof organizations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.177-183
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• 1999

The major object of this study is to investigate experimentally the experimental equation by the non-destructive testing methods of ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number, maturity which are applicable to the evaluation of compressive strength of concrete at early ages. Also test result of mix are statistically analyzed to infer the correlation coefficient between the maturity and the compressive strength of concrete. The results show good application of Logistic curve for estimating strength development under various curing temperature. The relation between ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number and compressive strength of concrete have low correlation coefficient, but maturity method show good correlation coefficient.

• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.1-7
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• 2023

The steel wheels of urban railway vehicles gather a lot of data through regular measurements during maintenance. However, limited research has been carried out utilizing this data, resulting in difficulties predicting the maintenance period. This paper studied a machine learning model suitable for mileage prediction by studying the characteristics of mileage change according to diameter and flange thickness changes. The results of this study indicate that the larger the diameter, the longer the travel distance, and the longest flange thickness is at 30 mm, which gradually shortened at other times. As a result of research on the machine learning prediction model, it was confirmed that the random forest model is the optimal model with a high coefficient of determination and a low root mean square error.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.169-179
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• 2011

Korea owns vast amount of apartment houses no less than those of world prominent countries, but did not pay enough efforts to maintain existing apartment houses and develop policies to reuse them due to growth driven policy of housing supply like construction of new houses. Korea constructed tremendous amount of houses in short period through government led forced house supplying policy, and resulted in excess houses such that present house supply rate happened to be reaching 110%. However, recently there are growing demand of change in housing policy due to social environmental changes like low birth rate and aging of society etc and nationals' demand for improvement of residential quality. When such social changes are demanded and 80% of apartment houses in Korea are less than 20 years old, renovations and remodeling of apartment houses are anticipated to emerge as important matter. In particular, the apartment houses in Seoul and the 1st generation new cities like Bundang and Ilsan etc have passed considerable period of time after construction and require safety measure, it is quite impending to raise engineers for the maintenance of existing apartment houses. Therefore, in this paper, direction for the raising of maintenance engineers in Korea was proposed through analysis of relevant qualification system for the apartment houses maintenance engineers in the U.S.

• The Korean Journal of Rehabilitation Nursing
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• v.17 no.2
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• pp.72-80
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• 2014

Purpose: The objective of this study was to analyze the factors affecting the stages of exercise behaviors changes of low back pain patients. Methods: The participants in this study were 220 low back pain patients who have been treated by therapeutic exercise or had the exercise treatment under the doctor's advice. The tools used for this study were the stages of exercise behavior change, intrinsic motivation questionnaires, and physical activity social support scale (PASS). Results: The group that did exercise (preparation stage, maintenance stage, action stage) was 75.9% but the group that did not exercise (precontemplation stage, contemplation stage) was 24.1%. Social supports from family members and friends and motivation affected the exercise behaviors changes. And 34.6% of the exercise behavior change can be explained by the social support (family, friend) and motivation. Conclusion: There were two recommendations for maintaining the exercise behaviors of low back pain patients based on theoretical background. First, we recommended more exercise programs which reinforce social supports from family and friend for constant exercise behaviors of low back pain patients. Second, more exercise programs for the low back pain patients who have similar health goals or problems were needed for motivating them to join the exercise programs.

• Steel and Composite Structures
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• v.26 no.2
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• pp.227-239
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• 2018

Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.177-181
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• 2020

Data on the crude protein requirements of elk doe are nonexistent and the data are essential for their management in Korea. Therefore, this study was conducted to evaluate the crude protein requirement for maintenance of elk doe. Three female elk deer were used in 3 × 3 Latin square design with three diets containing three levels of crude protein (CP) that contained low crude protein (approximately 12%), medium crude protein (15%), and high crude protein (18%). Each three elk doe trials included a 14-day preliminary period and a 5-day collection period. Crude protein intake was 4.83, 6.26, and 9.00 g/d for 12%, 15%, and 18% of CP level, respectively. Crude protein balances were 1.04, 1.41, and 4.14 for 12%, 15%, and 18% of CP level, respectively. The maintenance requirement for CP from the regression equation between CP intake and CP balance were 3.70 g/BW^0.75.