• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.198-204
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• 2010

The cover of truck agitator give in a part to prevent the lower flowing of fresh concrete when the concrete are transported from the ready mixed concrete plant to the construction field. As a result of the question data, it show up a dirty image to the general civil society. Due to the above image, it is predicted to affect the image of the construction company, so we did the site experiment of the flowing, the amounts of air, the temperature change of concrete with the concrete left in the site, to find out the usefulness. Also, for the comparing with this, we got the result by doing the inner experiment with the same condition. As the result of the experiment, the cover of truck agitator affect little to the reduction of slump. The change of the air amount, regardless of the existence of cover, was not effected much in proper level until 60minutes. In addition, The compression strength was proper to the goal design strength until 90minutes regardless of the cover of truck agitator exist or not exist.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.61-71
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• 2005

Cemented Sand and Gravel (CSG) is a material made by simple mixing of rock-based raw materials such as excavated soil and riverbed gravel together with cement and water. The use of CSG material for cofferdam and large dam is gradually increasing in Japan because a quarry and aggregate plants can be diminished. Also, the CSG method can reduce dam construction cost, construction duration and destruction of environment. In this paper, the basic strength characteristics of CSG, such as compressive strength, modulus of elasticity and stress-strain curve were investigated by unconfined compression test and large triaxial compression test. From the results of the experimental study, the correlation equations between elastic modulus and unit cement, age are proposed.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.602-602
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• 2015

가뭄에 대한 정의와 구분이 다양하게 존재하나 일반적으로 기상학적 가뭄으로부터 농업적 가뭄, 수문학적 가뭄, 사회경제학적 가뭄으로 전이되므로 강수량의 부족이 가뭄의 첫 번째 원인인 것은 자명하다. 최근까지 여러 가지 기상학적 가뭄지수가 개발되어 다양한 목적으로 세계 곳곳에서 활용되고 있으나, 그 중 적용사례가 가장 많은 것은 표준강수지수 (SPI; Standardized Precipitation Index)이다. 월단위로 계산되어지는 SPI는 우리나라와 같이 강수의 변동성이 큰 지역에서는 그 활용성이 떨어지는 경우가 있어 최근에는 일 단위 SPI를 산정하여 활용하는 경우도 있다. 그러나, 일단위 SPI는 가뭄기간 동안 가뭄단계가 'Extreme drought'에서 'Moderate drought'로 약해질 경우 가뭄 지속기간이 가장 긴 'Moderate drought' 단계에서 가뭄피해 및 체감하는 고통이 가장 클수 있어, 가뭄에 대응하거나 대국민 가뭄정보 전달에 한계가 있다. 가뭄에 대응하거나 가뭄정보 전달을 위해서는 가뭄이 지속되는 동안 가뭄단계가 높아질 필요성이 있다. 이에 본 연구에서는 가뭄사상의 특성 중 가뭄의 강도(Intensity)와 지속기간(Duration)의 특성을 모두 포함하는 가뭄의 심도(Severity)를 활용하여 기상학적 가뭄을 평가하였다. 일단위 SPI 값(강도)을 가뭄기간동안 누적하여 일단위 가뭄심도(SPI-S)를 산정하고 이를 통해 가뭄단계를 제안하였다. 또한 다양한 SPI 대상기간에 대해 최솟값을 취하는 Blended SPI에 대해서도 같은 방법으로 가뭄심도(SPIB-S)를 산정하고 가뭄단계를 적용하였다. 2001년, 2008-2009년, 2012년 가뭄사례에 적용한 결과 SPI-S(or SPIB-S)는 가뭄기간동안 단계적인 가뭄단계의 상승으로 당시의 가뭄상황을 잘 나타내었다. 이는 SPI-S(or SPIB-S)가 단계적인 가뭄대비와 대응 지수로 가뭄피해 경감에 활용도가 높을 것으로 판단되며, 가뭄상황을 지역민들에게 단계적, 일관적으로 전달할 수 있어 가뭄극복을 위한 시민참여를 유도하기에 유리할 것이다.

• Plant Journal
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• v.10 no.2
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• pp.28-37
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• 2014

Recently, it is considered that environment and energy are critical issues all over the world. In power generation sector in Korea, almost power stations are constructed and operated as cogeneration plants in conformity with this trend. KDHC(Korea District Heating Corporation) goes one step further adopting renewable energy technology like heat pump using wasted heat for energy-saving and environment improvement. This study investigates the performance characteristics by the location of waste heat recovery heat pumps of 5 Gcal/h capacity in 150 MW-class Gwang-gyo cogeneration plant using commercial software 'THERMOFLEX'. Prior to analysis, the simulations are performed with actual operation data, and then the validation of simulations is verified by checking the error within 2%. After verification, the simulations are carried out with 3 locations and the effect on electrical power output and heat output is analyzed. As a result, overall efficiency of cogeneration plant is the highest in the case of heat pump located before DH(District Heating) Heater because of the largest increase of heat output despite of decrease of electrical power output.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.84-93
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• 2010

Compaction of backfill material of Underground power lines is difficult, especially under pipeline. so it could cause structural problem because of low compaction efficiency. So various methods have been taken to solve the problem and one of them is CLSM(Controled low-strength material accelerated flow ability). But In other countries, these are already in progress for a long time to research and development and recently on practical steps. But, in our country, study for only general structures, not for underground power line structure that is being constructed at night rapidly. In this study, we performed property tests and indoor & outdoor test (3 cases). The tests showed flow ability reached at the limit construction(160 mm) flowability by 9 to 15 minute after starting to mix, and construction buoyant is lowering after placing CLSM by 70 % of theoretical buoyant that is calculated by unit weight of material. In this paper, we performed indoor tests and outdoor tests to estimate mechanical properties and to suggest construction method(using batch plant, setting spacer at 1.8 m and placing at 2m) for CLSM that using surplus soil. And the test showed good results for construction quality, workability and structure safety.

• International Commerce and Information Review
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• v.10 no.4
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• pp.457-491
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• 2008

As stage equipment export markets along with special lighting service lack the attraction for already globally established businesses, such markets can be viewed as an advantageous opportunity for SMEs as in general. In reality, global businesses tend to focus on large construction projects and this indicates relatively less substantial markets such as stage equipment and special lighting service export are more suitable for SME businesses. However, possible problems may be recognized as following; doubtful capabilities by such businesses to join in the vast and competitive global market and pursue manufacturing and service based export. This point is also supported by the fact that such in general SME businesses have substantially less experience in exporting products and services abroad. Realizing the distinctive features of the Korean economy, it is unarguable that every sector and area of global market must be regarded and monitored closely. Hence, it can be argued that there is an imminent need for establishment of supportive institution to assist export process of combination of stage equipments and special lighting service. This study emphasizes the need to improve export process of stage equipments, special lighting services as well as other related products and services which have been focused in domestic market only until now. Further, it also analyzed the potential prospect of such direction reconciling current crisis our manufacturing industry is facing. Even though it maybe regarded as one of the niche market for export of Korea in the short term view, stage equipment and special lighting service industry may rapidly grow as the global cultural industries have grown along with the increase of national income earnings overall. Due to such advantageous features, it can be expected that such industries will show strong growth in the near future. After analyzing the fact that Korea's plants (eg. powerplants) export sector is at its boom, there is a need to transform stage equipment and special lighting service export market into a primary market from a secondary(niche) market for SMEs. This study is viewed from the Korean economic and export sector aspect in the aim of seeking a solution to conquest our realistic limit in our export sector by developing a suitable export model. There have been cases of very few attempts to expand abroad by SMEs who have failed miserably due to their failure to adapt to foreign culture, practice and languages as well as substantial lack in experience in export marketing. Despite this, neglecting our manufacturing industry as it is which is showing its limit and problems is out of option therefore, it is imminent that we come up with an effective measure to address this problem and service export can be suggested as one of them. This study reveals manufacturing-service export model of stage equipment and special lighting service and its related areas is recognized as a field with a very strong future and furthermore, it is expected to bring synergy effects in manufacturing and services sector as well. Further, the operation strategy contains combination, composition and fusion(convergence) of manufacturing and service sectors which could derive various of export products which displays greater success probability or this export model. The outcome of this research is expected to become a useful source for enterprises related to such industry which are seeking a possible global expansion. Furthermore, it is also expected to become a catalyst which fastens the process of global expansion and not only that, we are firmly assured that this study will become an opportunity to improve our current policies and institutions related to this area's export market.