• Resources Recycling
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• 제18권3호
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• pp.20-26
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• 2009

The objective of this study is to investigate the properties of fresh concrete with recycled coarse and fine aggregates. Four different kinds of aggregate with natural, recycled aggregates were prepared. The concrete mixtures were produced with test parameters of replacement ratio of recycled aggregate. The properties of the fresh concrete were measured by means of slump and air content according to elapsed time. Quality control method to maintain the constant total mixing water for recycled aggregate concrete was suggested. The all concrete mixtures were produced with approximately the same slump on the job site after an hour. Test results indicated that compressive strength of concrete with constant slump is not affected by the replacement ratio of recycled aggregate. Also the practical way for the quality control of recycled aggregate concrete is to maintain the constant total mixing water.

• Corrosion Science and Technology
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• 제9권6호
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• pp.310-316
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• 2010

Recently a fuel oil of the diesel engine of the marine ship is being changed with heavy oil of low quality as the oil price is higher more and more. Therefore the wear and corrosion in all parts of the engine such as cylinder liner, piston crown, spindle and seat ring of exhaust valves are predominantly increased. In particular the degree of wear and corrosion of piston crown is more seriously compared to the other parts of the engine due to operating in severe environment such as the high temperature of exhaust gas and repeating impact. Thus the repair weldment of the piston crown is a unique method to prolong the its life in a economical point of view. In this case, filler metals having a high corrosion and wear resistance such as stellite 6, Inconel 625 and Inconel 718 are mainly being used for repair welding. However it has been often happened that piston crown on the ship,s job site is being actually inevitably welded with mild filler metals. Therefore in this study, filler metals such as E4301, E4313 and E4316 were welded at SS401 steel as the base metal, and corrosion property of their weld metals in the case of post weld heat treatment or not was investigated with some electrochemical methods such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram and polarization resistance etc. in 0.1% $H_2SO_4$ solution. Corrosion resistance of the weld metal of E4301 was better than the other weld metals in the case of no heat treatment, however, its resistance was considerably decreased with post weld heat treatment(annealing:$625^{\circ}C$, 2 hr) compared to other weld metals. The weld metals of E4313 and E4316 showed a relatively good corrosion resistance by post weld heat treatment.

• Journal of the Korea Institute of Building Construction
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• 제18권3호
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• pp.251-257
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• 2018

There are various quality deteriorations of concrete such as plastic, drying shrinkage due to abrupt moisture evaporation, slump loss and cold joint under hot weather condition. To protect from above deteriorations, several kinds of modified bubble sheets have been applied to secure heat insulation performance. But, there is not enough application cases of bubble sheets at job site under hot weather condition. The objective of the paper is to investigate the temperature profile and crack occurrence of the concrete covered with five different kinds of surface curing sheets, which is placed under hot weather condition. Single layer transparent bubble sheet, white colored bubble sheet, aluminum metalizing bubble sheet and PE film are adopted for surface curing sheets. Test results indicated that application of aluminum metalizing bubble sheet had most favorable effect on the reduction of on temperature rise and on the crack reduction of concrete. But due to larger reflection of light by aluminum, it brings about visual pollution to the workers. Hence, the application of white colored bubble sheet can be the most desirable alternative to protect the concrete from hot weather in the field.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.710-713
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• 2007

This paper presents the findings obtained from several series of analysis on the fatal accident, which are maintained by Korean Production Household Mascot Safety Industrial Complex, relative to fall. The fall accidents occurred in 5 years, from 2002 to 2006, were analyzed. The statistic relative to the fatal accidents analyzed according to different classifications such as accident rate, project amount, project type, cause, type of occupation. years of experience, and time in a day. This research would contribute to ensure the effectiveness of safety policy so as to enhance worker safety. In addition, cluster analysis was applied to find the major contributors on the fall accidents. Cross referencing between occupation and type of work, and occupation and cause were established so that the occurrence statistics of fall accidents were investigated.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.925-928
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• 2007

As the field report data does not normalize, ordering organization requires different form every time and field reporters make out form as random, data and report to the ordering organization by different medium such as FAX, e-mail, paper document. Therefore, Field reporters must set and make out same information in required pattern. And ordering organization is being responsible for side works of totalizing and processing the reported data. This research suggests the electronic document unification about monthly construction progress report and construction present condition report system. In addition, it suggests electronically processing function that can handle field report business to unifying electronic documents. As using the result of this research, it will improve the work efficiency and simplify in report business.

• Archives of design research
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• 제15권3호
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• pp.149-156
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• 2002

Through academic-industrial collaboration program, special knowledge and human resources in the university are utilized in the society and it may contribute to the development of industry and enhance the competitiveness of the corporation to the activation and acceleration of the regional economy and finally to the enhancement of competitiveness of national industry in international level. This study is based upon design process for the development of body-shower product for bath room, and expected to be used as an important educational material for establishment of order-based education system which conforms to the job site needs that may be analysed from feedback of product results and for practical learning.

• Journal of the Korean Recycled Construction Resources Institute
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• 제7권4호
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• pp.358-366
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• 2019

The purpose of this study is to explore the possibility of estimating optimum surface finishing work time of the fresh concrete placed at the job site by applying a surface hardness test meter(Durometer). Tests are carried out by measuring and comparing the Proctor penetration resistance test and hardness test by Durometer. Correlations between Procter penetration test and hardness test by Durometer were obtained. Two different types Durometer were applied to estimate setting time. Test results indicate that the measurement of the Durometer and the test of the Proctor penetration resistance are highly correlated. When measuring the initial setting time with Durometer, initial setting time is reached when the hardness value by the type C Durometer is reached around 42HD, and when final setting is measured with the type D Durometer, the surface finishing work time limit and curing time can be estimated with 10HD of Durometer.

• International Journal of Highway Engineering
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• 제18권2호
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• pp.61-71
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• 2016

PURPOSES: The objective of this study was to determine the optimum ratio of mix design, for a reclaimed asphalt pavement (RAP) content of 100%, for spray injection application. METHODS: A literature review revealed that spray injection is an efficient and cost-effective application for fixing small defective regions of an asphalt pavement. Rapid-setting polymer-modified asphalt mixtures prepared from two types of rapid-setting polymer asphalt emulsion were subjected to Marshall stability and wet track abrasion tests, in order to identify the optimum mix designs. RESULTS and CONCLUSIONS : Different mix designs of type A and type B emulsions were prepared using RAP and virgin aggregates, in order to compare the performance and determine the optimum mix design. The performance of mixtures prepared with RAP was superior to that of mixtures containing virgin aggregates. Moreover, for optimum ratio of the design, the binder content prepared from RAP was set to 1~2% lower than that consisting of virgin aggregates. Compared to their Type A counterparts, type B mixtures consisting of a reactive emulsion performed better in the Marshall stability and wet track abrasion tests. The initial results confirmed the advantages associated with using RAP for spray injection applications. Further studies will be performed to verify the difference in the optimum mix design and performance obtained in the lab-scale test and tests conducted at the job site by using the spray injection machine.

• Archives of Reconstructive Microsurgery
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• 제14권2호
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• pp.105-111
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• 2005

Perforator flaps have become increasingly popular in microsurgery nowadays and are being used widely for many cases of reconstruction after trauma and cancer ablation. And thoracodorsal perforator based free flap is one of them having the merits of carrying a large skin paddle with leaving intact innervation and function of the remaining latissimus dorsi muscle. We made a homogeneous thin flap excluding the main muscle with a long vascular pedicle and tried to decrease the donor site morbidity. But, it needs a long learning-curve and we have met marginal flap necrosis frequently. Besides, prolonged operation time for complete perforator dissection may be a tedious job to the microsurgeon. To overcome these disadvantages, we usually included very small portion of the latissimus dorsi muscle during this flap elevation around the pedicled 2-3 thoracodorsal perforators during this flap elevation. We performed 3 cases of thoracodorsal perforator based free flap at Hallym university sacred heart hospital between May and August 2005 for the soft tissue defect of the scalp and feet. The average flap size was $8{\times}14\;cm$. Although it is not a true perforator flap, we can get the reliability for the flap survival with much better blood circulation and save the time of one or two hours to dissect the perforators completely. All cutaneous flaps survived completely without any complication except one fatty female who had the very small superficial fat necrosis due to flap bulkiness. We believe the thoracodorsal perforator based free flap can be extended its versatility and reliability by including the very small portion of the muscle around the perforators.

• Journal of KIISE:Computing Practices and Letters
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• 제10권4호
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• pp.351-363
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• 2004

Recent commencement of digital broadcasting has enabled various TV programs through hundreds of channels. As a result, it becomes a time-consuming job for the TV audience to look up newspaper or TV magazines for the schedule of a specific TV program. To relieve this problem, digital broadcasting usually provides an EPG(Electronic Program Guide) for the audience. Currently. most EPG services are focusing on the visual delivery of information through a web site, digital TV or mobile devices. However, this approach could cause a serious restriction to some users including drivers or visually handicapped persons, who can't input keywords for the search. In order to solve this problem, in this paper, we propose a VoiceXML-based EPG retrieval system that enables even such special users to browse EPG. conveniently using a mobile phone. We implemented a prototype system and proved its effectiveness through experiments.