• 대한치주과학회:학술대회논문집
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• 2003.11a
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• pp.87-88
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• 2003

• 대한치주과학회:학술대회논문집
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• 2006.11a
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• pp.62-63
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• 2006

• Management & Information Systems Review
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• v.36 no.4
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• pp.81-102
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• 2017

This study examined the income and price elasticities of tourism demand model by using the ARDL models. This paper used the ARDL & ARDL-RECM model based on the annual number of tourists arrivals, GDP and CPI including tourists from the US, Japan and China entering Korea. First, the income elasticity of the US was inelastic and insensitive necessities for long-run US tourists in the ARDL model. China's income elasticity was elastically sensitive luxuries. Second, the US and China's own price elasticities were very elastic to tourism demand in both models. Third, the US's cross price elasticity showed the relationship between inelastic positive substitutes and inelastic negative complements in China in ARDL model. The cross price elasticities of the US and China showed inelastic positive substitutes in the ARDL-RECM model. Fourth, the coefficients of the error correction term were such that the actual sign and the expected sign of the US and China coincided with the negative sign in the ARDL-RECM model. Therefore, first, it can be established in a tourist policy or tourism strategy through income elasticity. Second, we can improve the quality and differentiation of products, recognizing that Korea's tourism price is more elastic than other markets through price elasticity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.116-121
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• 2019

In order to evaluating applicability of RAP (recycled aggregate powder) in mortar, in this study, physical and mechanical tests was carried out. Material characteristics of recycled aggregate and RAP were evaluated and the mechanical properties of mortar replaced with RAP were analyzed. Test result of sieve analysis showed that as the milling time increased the fineness modulus was decreased and the distribution of 0.6 mm particle size was found to increase. The fluidity of mortar mixture substituted with RAP tended to increase than Plain mixture. It was result that the increasing fluidity was affected by unreacted surplus water in the mortar as the binder was replaced with RAP. From the compressive strength result of the mortar subjected to RAP, it was found that the RAP was able to replace up to about 10% of unit binder weight although the compressive strength of mortar was decreased as the RAP replacement increased. From the above study, it can be concluded that the physical properties of RAP satisfied the quality standard of aggregate for replacement with fine aggregate. Moreover, in case of the RAP was replaced up to 10% of unit cement weight, it was able to be possible to improve fluidity and compressive strength of mortar.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.95-103
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• 2012

In order to improve the dimensional stability and mechanical performance of cement-based composites, the effect of an expansive admixture based on calcium sulphoaluminate (CSA) on the shrinkage and mechanical properties of strain-hardening cement-based composite (SHCC), which exhibits multiple cracks and pseudo strain-hardening behavior in the direct tension, is investigated. Polyethylene fibers reinforced SHCC mixtures with three levels (30, 70, and 100MPa) of compressive strength were compared through free shrinkage, compressive strength, flexural strength, and direct tensile strength measurements. The SHCC mixtures were cast with and without replacing 10% of Portland cement content with CSA admixture. According to test results, CSA admixture is effective in reducing shrinkage of SHCC material. SHCC mixture with CSA admixture exhibited a little higher strength than companion mixture without CSA admixture.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.119-127
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• 2014

The application of sulfur polymer emulsion (SPE) as an acrylate substitute for semi-rigid pavement grout was evaluated, and the performance improvement by employing PVA fibers were also evaluated. The result indicated that the filling ratio of semi-rigid pavement material decreased as the fiber content increased, but it was measured to be 92~94% in every mixing condition, which satisfies the target performance, 90%. The maximum Marshall stability value of semi-rigid pavement material was measured to be 25.4 kN, which is about 4.7 times higher than the Korean Standard required for semi-rigid pavement material, 5.0 kN. The dynamic stability evaluation of semi-rigid pavement material indicated that the resistance to deformation from the wheel tracking test was improved by an SPE substitution, and in every mixing condition, the deformation converged to a constant value after 45 minutes with the same dynamic stability of 31,500 times/mm. The strain at the flexural failure was about 0.53%, which shows superior rigidity to asphalt pavements. The examination of abrasion resistance and impact resistance showed that the loss ratio was 9.8~6.0% in every mixing condition, which indicates a good abrasion resistance. Also, when fiber content ratio was 0.3%, the impact resistance was 2.82 times higher compared to plain (i.e., when fibers were not added). In the limited range of this study, an SPE substitution ratio of 30% was found to be an optimal level considering the mechanical and durability performance. In addition, it is thought that semi-rigid pavement material with superior performance could be manufactured if fiber content ratio up to 0.3% is applied depending on the purpose of use.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.777-780
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• 2008

There were some attempt to reuse water with sludge combinative water for ready mixed concrete. But recycling water consist of cement, aggregate and chemical admixture. So it caused deterioration of concrete. The object of this study was to search for recycling method of the recycling water sludge as mineral admixture. This experiment dealed with the effect of $2.5{\sim}12.5$% range of the recycling sludge which can be used for admixture binder(BFS, FA, BFS+FA) on properties of activated recycling water sludge for admixture of concrete. As a result, Although the slump levels reduced and air contents increased as sludge replacement levels increased, it didn't change highly. The compression strength of concrete slightly increased with an increasing amount of recycling water sludge replacement.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.825-828
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• 2009

고형원료인 폐기물의 감량화 및 자원화 기술 중 가장 대표적인 기술로 폐기물의 소각(incineration)기술과 가스화(gasification)용융기술을 들 수 있다. 폐기물 가스화 기술은 폐기물 내의 탄소, 수소 성분을 가스화하여 CO, $H_2$가 주성분인 합성가스(synthesis gas, syngas)로 전환하여 불연물은 용융되어 환경적으로 무해한 슬래그로 회수하는 기술이다. 폐기물 가스화 용융 시스템으로 발생된 합성가스를 재순환하여 사용하는 합성가스 재순환시스템을 통해 가스화에 필요한 열을 시스템 내에서 대체하여 사용하는 기술개발은 폐기물 가스화 용융기술의 경제성을 높일 수 있다. 본 연구에서는 고형 폐기물 가스화반응에 의해 발생되는 합성가스를 재순환하여 폐기물 가스화 용융 시스템내의 자체 에너지원으로 활용할 수 있도록 하는 합성가스 재순환 시스템 및 버너의 운전특성을 고찰하였다. 합성가스의 재순환 장치에서의 운전 압력 제어 및 유량제어를 통해서 안정적인 합성가스 재순환 성능과 재순환버너의 연소 성능을 유지할 수 있었다. 합성가스 재순환버너에 의한 16,800 $kcal/Nm^3$ 조건 및 33,600 $kcal/Nm^3$ 조건에서 운전시에도 가스화기의 운전온도는 안정적으로 유지됨에 따라 생산된 합성가스의 가스화기 보조연료 대체 및 에너지절감이 가능한 것으로 판단된다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.319-320
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• 2010

This Study aimed to investigate fundamental properties of PHC pile using waste TFT-LCD glass powder. Through the present study, waste TFT-LCD glass powder may be taken into consideration for the application of mineral admixture for PHC pile.

• 발명특허
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• v.31 no.6 s.360
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• pp.40-43
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• 2006

무분별한 벌목으로 숲이 점차 사라지고 있다. 숲이 사라지면 지구를 보호하는 오존층도 사라지게 되고 수억 년 동안 인류가 누려온 윤택한 자연의 생태계도 위협을 받게 된다. 그리고 인류의 삶 역시 위험에 빠지게 됨은 자명한 일이다. 이처럼 환경 파괴의 문제가 대두됨에 따라 각국에서는 친환경 대체재에 대한 관심이 높아지고 있는 것이 현실이다. (주)에코인조목재에서는 폐플라스틱을 활용한 인조 목재의 개발로 환경을 지키는 것은 물론 기존의 수입 목재를 대체하여 외화지출을 절감하는 효과를 거두었다. (주)에코인조목재에서 개발한 PE 인조 목재는 가두리양식용 기자재로 활용하게 되는데 이는 국토의 삼면이 바다인 대한민국에서 추구하는 해양 수산업 국가 위상에 걸맞는 제품으로 평가받고 있다.