• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.189-196
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• 2003

Soil-cement column is often used as a contaminant barrier. This study presents the results of experimental study performed to investigate the changes of properties of soil-cement column under the attack of acids. Sulfuric nitric, and ascetic acid were used as contaminants. Specimen were made of clayey and sandy soils with addition of cement and water Permeability of soil-cement decreased with time during permeability test. When significant amount of acid percolated the specimen, permeability increased and compressive strength decreased due to the dissolution and leaching of cement and its chemical reaction compounds. Sulfuric and nitric acid were more effective than ascetic acid in deteriorating soil-cement column. Amount of acid required to lower the pH of soil cement below 12 was calculated from the results of permeability tests. This leads to a conclusion that, under the conditions employed in this study, the chemical stability of soil-cement column could be maintained against acid attack for longer than generally accepted lifetime of contaminant barriers.

• Journal of the Korea Safety Management & Science
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• v.6 no.1
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• pp.49-60
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• 2004

Industrial facilities are becoming more complex and various with rapidly developing technologies. A number of installations and equipments are increased to improve productivity, and they are operated under the condition of high temperature and pressure. They are continuously repaired, replaced or abolished because of the deterioration with time, but their repair and replacement are not easy for economical and environmental concerns. If possible, the deteriorating equipments should be inspected and repaired effectively considering the state of maintenance and preservation, economic efficiency, and safety. That's where RBI(Risk Based Inspection) fits in. Even if RBI technology has been known among specialists, there were no tools readily available and it was hard to practice and apply RBI in industrial inspection and safety management. In the development of the qualitative RBI, the overall algorithm adopted API-581 BRD. The qualitative RBI program was developed to search the appling process.

• Journal of Ocean Engineering and Technology
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• v.28 no.6
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• pp.533-539
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• 2014

A maintenance system for an offshore plant uses an optimal maintenance method, process, and period based on operation information data and economic evaluation techniques. Maintenance is performed after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating. A maintenance system is based on the use of real-time data to prioritize and optimize the LNG-FPSO topside equipment resources.

• Journal of Applied Reliability
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• v.5 no.3
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• pp.373-379
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• 2005

In many cases, it is more practical and economical to repair a system than to replace the whole system or to perform a complete overhaul when the system fails. Two basic replacement policies were proposed by Barlow and Hunter(1960) and Morimura (1970), in which the minimal repair times are identically distributed. But, as Lam(1988) pointed out, in many cases of deteriorating system, in view of ageing and cumulative wear, the repair time will tend to be longer and longer. In this note, the two basic replacement policies are considered for a repairable system with linearly increasing repair times. Optimal policies, which maximize the steady state availability of the system, are obtained for the Weibull failure rate case.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.151-160
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• 2010

Housing is one of the most important factors determining the quality of rural life. Housing condition in rural area has been deteriorating over the past years in spite of many rural development programs. Korean government formulated 'Rural Housing Environment Improving Plan' including rural rent-house program in 2006. This study aims to find the fundamental intension of rural people for adopting the rent-house system in rural area. To do this, background and current state of rural rent-house program are presented and the demand for rural rent-house is analyzed based on the survey results done by Korea Rural Community Corporation in 2005. Major findings from the survey analysis imply that the size/age/ownership of the current houses and the age of householders, motive and time period of current residing, and components of households are significant factors when considering whether they are willing to apply rural rent-house.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.13-17
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• 1988

An efficient model for three-dimensional analysis of multistory structures with flexible floor diaphragms is proposed in this paper. Three-dimensional analysis of a building structure using a finite element model requires tedious input data preparation, longer computation time, and larger computer memory. The model proposed in this study is developed by assembling a series of two-dimensional resisting systems and is considered to overcome the shortcomings of a three-dimensional finite element model without deteriorating the accuracy of analysis results. Static and dynamic analysis results obtained using the proposed model are in excellent agreements to those obtained using three-dimensional finite element models in terms of displacements, periods, mode shapes.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E2
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• pp.67-74
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• 2005

Domestic anthracite contains a large amount of fine particles, which causes to fire the back side of the boiler and to form the clinker deteriorating the combustion efficiency. At this time, the fine limestone adsorbents for a desulphurization agent may be used to facilitate an aggravation of the boiler, so that fine mode of limestone (<0.1mm) has been used no more than $25\%$ in local power stations of Korea. The present test carried out with an in-situ boiler, however, showed that higher content $(up\;to\;50\%)$ of fine limestone particles did not entail any mal-function. In addition, the desulphurization was found to be as good as the old mode of limestone adsorbents.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.7-16
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• 1999

To maintain thereasonable temperature in the engines is very important to keep the steady combustion state of engine and to prevent increasing of oil consumption , deteriorating of lubricant, shortening of the life time of engine and decreasing of material strength. The method of energy balance for divided elements of radiator and engine-oil cooler is considered to analyse the performance of radiator and engine-oil cooler. The data obtained by engine test and vehicle cooling tunnel test are applied to program for calculation of radiator outlet temperature. As a result, data obtained by numerical analysis agree well with those by experiments. And thus, it is concluded that this simulation program is available in developing the cooling system for a new car.

• Computational Structural Engineering
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• v.2 no.1
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• pp.47-53
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• 1989

An efficient model for three-dimensional analysis of multistory structures with flexible floor diaphrgms is proposed in this paper. Three-dimensional analysis of a building structure using a finite element model requires tedious input data preparation, longer computation time, and larger computer memory. The model proposed in this study is developed by assembling a series of two-dimensional resisting systems and is considered to overcome the shortcomings of a three-dimensional finite element model without deteriorating the accuracy of analysis results. Static and dynamic analysis results obtained using the proposed model are in excellent agreement with those obtained using three-dimensional finite element models in terms of displacement, periods, and mode shapes. Effects of floor diaphragm flexibility on seismic response of multistory building structures are investigated.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.147-152
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• 2004

With the rapid development of urban suburbanization, a plenty of commercial operation of suburban environmental resource, the environment in suburb is more and more deteriorated. It also leads some passive effect on ecology, human, society and nature etc. At the same time, a serial of emergency rescue action has been implemented to decrease the deteriorating of suburban environment. For example, some important ecology nature reserves were built up; some compulsive protections have been put in practice for some key resource development region and gotten some good achievements. However, we still face the problem is that how to balance the contradiction between suburban environment resource development and conservation. It's necessary to introduce some western advantage management ideas, combined our actual situation, to find a way which is the most benefited to combine our country's suburb environment development and use.