• Journal of Korea Technology Innovation Society
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• v.2 no.2
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• pp.219-232
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• 1999

연구개발 지원산업은 연구개발 활동을 직·간접적으로 지원하는 산업을 의미한다. 이러한 산업에 대한 개념화는 연구개발 활동의 전문화(professionalization), 분업화(division of labor)가 진행되고 있음을 의미하는 동시에 연구개발체제의 유연성 제고 및 고도화, 효율화가 이루어지고 있음을 나타내고 있다. 우리의 경우 (과학기술혁신을 위한 특별법) 제 15조 등을 통하여 연구개발 지원사업에 대한 특별지원제도의 시행을 명시하고 있으나 현재까지 연구개발 지원사업자를 지정·육성하기 위한 기본현황 파악이나 분석이 이루어지지 않은 실정이다. 본고는 이러한 수요를 반영하여 국내에서의 연구개발 지원산업에 대한 수요를 중심으로 실태를 파악 ·분석하는 동시에 산업지원 육성방안을 제시하고 있다. 국내 연구개발 지원산업의 규모를 추정해 보면 97년 현재 약 3,000억원에서 4,000억원의 규모로 나타나며, 이중 기술정보서비스업이 약 27.0%, 연구장비 및 시험 ·평가 ·검색 ·분석업이 약 38.4%, 연구개발 설계·자문업 등 기타사업이 34.6% 로 나타나고 있다. 연구개발지원 기능은 시험·검사 기능과 기술정보제공 기능이 대부분을 차지하고 있고, 전자의 경우는 내부처리의 비중이 높고 후자의 경우 외부의 전문기관을 이용하는 비중이 높게 나타나고 있다. 특히 기업이 연구개발활동 수행시에 필요한 지원기능을 외부에 위탁할 경우에 느끼는 애로사항은 첫째, 외부 전문위탁기관의 부족 및 정보 미흡이 가장 크고, 둘째, 전문기관의 해외정보력·경쟁력 부족이 다음이며, 공공기관의 지원기능이 미흡하다는 애로사항에 대한 비중이 상대적으로 낮게 나타나고 있다. 연구개발 지원산업을 특별지원·육성하기 위한 기본관점은 특별법의 시행령을 구체적으로 실행하기 위한 시행계획의 수립과 연구개발 지원산업의 육성 시책의 추진 절차의 결정, 사업자 선정, 지원 사항 등으로 제시될 수 있다. 먼저, 기업 연구개발활동의 고도화·효율화를 위해 연구개발 및 기술개량에 필요한 업무 중 기술정보서비스와 연구시험·평가·검사·분석 그리고 중소기업 기술집약화를 지원하는 사업 등을 연구개발 지원산업으로 범위를 정할 필요성이 있다. 다음으로 연구개발 지원사업자를 별도로 선정·인정하는 방식으로 지원해야 할 필요성이 있다. 기존의 산업 지원방식으로는 연구개발 지원기능이 주된 활동으로 인정받을 수 없으므로 국내 연구개발 지원기능의 발전에 한계가 있다. 따라서 취약한 여건을 감안하여 연구개발 지원산업을 육성하지 않게 되면, 각 분야별로 민간사업자의 참여가 거의 이루어지지 않거나, 참여해도 연구개발 지원 기능의 발전보다는 기존의 사업이 주가 될 가능성이 크다. 연구개발 지원 사업자의 지정 지원방식과는 별도로 이루어질 수 있는 지원활동에 대한 지원은 기업회계처리상의 문제와 일관성이 있는 시책추진 및 효과를 기대하기 어렵기 때문에 사전에 동산업의 참여 자격·능력을 갖춘 사업자에 대해서는 제한없이 참여할 수 있도록 Positive System으로 추진해야 할 것이다. 그리고 연구개발 지원사업자에 대한 지원내용을 조세·금융 등 직접적 지원과 타 제도와의 연계지원 그리고 정부구매 등 시장지원 등이 아울러 다양하게 추진될 필요가 있다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.6
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• pp.531-539
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• 2017

This paper deals with the development of bonded joints for fibre reinforced plastic (FRP) hull structures using moulding-in concept. Focus is placed on bonded in-plane connections between two adjacent panels that could form the boundaries of hull structural module. Traditional construction in FRP hull structures requires the construction of a mould, usually from steel or aluminium. In this construction the FRP materials are laid in the mould, and resin is saturated, and then the structural member is cured. This is expensive since it involves the fabrication of metal hull mould for every different hull type, which is sacrificed after the production of the FRP ship. One way of encouraging greater use of FRP in ship construction is to investigate the possible construction of FRP hull structures in a similar manner to metallic ships, that is in terms of blocks or modules. Such a manner of construction would eliminate the need for expensive hull moulds permitting greater flexibility in the construction of FRP ships. The main issue then would be the design and construction of adequate bonded connections between adjacent panels. To fulfill this object, the simplified and automated way of manufacturing joint edge shapes for bonded joints is developed, and their structural assessment is performed in both experimentally and numerically.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.459-465
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• 2012

This study analyzed the effect of semi-rigid rafter-purlin cross-linking connection and driven steel pipe base on the static behavior of plastic greenhouse (PG). To promote the time and cost efficiency of the assembly process, each cross-linking connections of space arch type grid that consists of rafter and purlin is linked with steel-wire buckles, and each end of the rafters was driven directly to the ground to support the PG structure. However, in the design process, cross-linking connections and bases are idealized by being categorized as fully rigid or frictionless pinned, which does not appropriately reflect actual conditions. This study takes a full-scale loading test of PG and analyzes the effect of member cross-linking connections and driven steel pipe base on the behavior of a structure. The analysis provided a basis for determining the rigidity factor of member cross-linking nodes needed for finite element analysis, and the reliability of the result regarding the static behavior of PG.

• Economic and Environmental Geology
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• v.41 no.4
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• pp.383-392
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• 2008

This study aims to evaluate the mechanical-chemical stability of used coal ash blocks, for improving fishing grounds. The surface of weathered ash blocks in seawater showed a decrease in the Ca and an increase in the Mg contents, compared to that of fresh blocks. This result reflects the substitution of Ca by Mg in seawater. The compressive strengths of ash blocks submerged into seawater during 12 months ranged from 235.23 to $447.43\;kgf/cm^2$; this is higher than the standard strength of wave-absorbing blocks($180\;kgf/cm^2)$ that are used for harbor construction. In addition, the compressive strength of ash blocks tends to increase with increasing installation time in seawater. The result of leaching experiments on coal ash blocks by Korean Standard Leaching Test(KSLT) method showed that leached concentrations of most metals except Cr(that leached up to 50 ppb, approaching standard concentration) do not exceed the seawater quality standards. A long-term(112 days) heavy metal leaching test to analyze seawater without mixing-dilution also showed that the concentrations of leached heavy metals, except for Cu, under anaerobic conditions do not exceed the seawater quality standards. Accordingly, the use of coal ash blocks in marine environments appears to be safe from chemical and mechanical factors that decrease the efficiency of concrete. Also, leaching concentration of Cu seems to be stable by decrease of leaching concentration due to dilution of seawater.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.15-23
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• 2023

The grouting method is a method of construction for the purpose of waterproofing and reinforcing soft ground. When grout is injected into the ground, there are various types of penetration and diffusion of grout depending on the shape of the ground, the size of soil, the porosity, and the presence or absence of groundwater. the current situation. Therefore, in this study, to investigate the penetration performance of the grouting to conductive material, laboratory tests were performed on the addition of the conductive material. In the injection test, 0%, 3%, and 5% of the mixed water were added as conductive materials to the grout, and the original ground condition was composed of various types of ground composed of gravel and silica sand. Conductive grout is injected by pressure into the model ground using a dedicated injection device, and the injection time (t), pressure (p), flow rate (v) and injection amount (q) are measured, and the hardened body injected in the model ground is collected. Penetration performance was evaluated. In the results of the grout injection experiment, the amount of conductive material used and the grout injection rate showed an inverse relationship, and it was confirmed that the penetration pattern was changed according to the size of the soil particles in the model ground. The grout containing the conductive material has relatively good penetration into the ground and excellent strength and durability of the hardened body, so it was judged that it could be used as an additive for measuring the penetration range of the grout.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.65-73
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• 2008

In the current practice for slope stability problem in Japan, the shear strength, $\tau$, mobilized along the failure surface is usually estimated based on an empirical approximation in which the cohesion, c, is assumed to be equal to the soil thickness above the supposed slip surface, d(m). This approximation is advantageous in that the result of stability analysis is not influenced by the designers in charge. However, since the methodology has little theoretical background, the cohesion may often be grossly overestimated, and conversely the angle of shear resistance, $\phi$, is significantly underestimated, when the soil thickness above the supposed slip surface is quite large. In this paper, a case record of natural slope failure that took place in Hyogo Prefecture in 2007, is described in detail for the case in which the shear strength along the collapsed surface was carefully examined in a series of direct shear box (DSB) tests by considering the effects of in-situ shear stress along the slip surface. It is demonstrated that the factor of safety agrees with that of in-situ conditions when the shear strength from this kind of DSB test was employed for the back-analysis of the slope failure.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.355-363
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• 2023

In safety assessment of a aged bridge, dynamic characteristics and displacement are directly related to the rigidity of the structural system, especially displacement is the most important factor as the physical quantity that the bridge user can directly detect. However, in order to measure the displacement of the bridge, it is difficult to install displacement sensors at the bottom of the bridge and conduct traffic blocking and loading tests, resulting in increased costs or impossible measurements depending on the bridge's environment. In this study, a method of measuring the displacement of a bridge using only accelerometers without installing displacement sensors and ambient vibration without a loading test was proposed. For the analysis of bridge dynamic characteristics and displacement using ambient vibration, the mode shape and natural frequency of the bridge were extracted using a TDD technique known to enable quick analysis with simple calculations, and the unit load displacement of the bridge was analyzed through flexibility analysis to calculate static displacement. To verify this proposed technology, an on-site test was conducted on C Bridge, and the results were compared with the measured values of the loading test and the structural analysis data. As a result, it was confirmed that the mode shape and natural frequency were 0.42 to 1.13 % error ratio, and the maximum displacement at the main span was 3.58 % error ratio. Therefore, the proposed technology can be used as a basis data for indirectly determine the safety of the bridge by comparing the amount of displacement compared to the design and analysis values by estimating the displacement of the bridge that could not be measured due to the difficulty of installing displacement sensors.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.12-23
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• 2024

In this study, a structural concrete square beam was developed using the centrifugal molding technique. In order to secure the bending stiffness of the cross section, the hollow rate of the cross section was set to 10% or less. Instead of using the current poor mixture of concrete and a concrete mixing ratio with a high slump (150-200) and a design strength of 100 MPa or more was developed and applied. In order to investigate the durability of centrifugally formed PSC square beams to be used as the superstructure of the avalanch tunnel or ramen bridge, the durability performance of ultra-high-strength centrifugally formed concrete with a compressive strength of 100 MPa was evaluated in terms of deterioration and chemical resistance properties.Concrete durability tests, including chloride penetration resistance, accelerated carbonation, sulfate erosion resistance, freeze-thaw resistance, and scaling resistance, were performed on centrifugally formed square beam test specimens produced in 2022 and 2023. Considering the information verified in this study, the durability of centrifugally molded concrete, which has increased watertightness in the later manufacturing stage, was found to be superior to that of general concrete.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.33-42
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• 2012

The efficiency of the current design methods for computing pile resistances is analyzed using field load-settlement tests results. Twelve load-settlement test data for drilled shafts and bored piles were obtained from the literature. These load-test data were fitted using the t-z method. Subsequently, the ultimate resistances were evaluated based upon the failure criteria from following methods: (1) the Davisson's approach and (2) settlement corresponding to 5% or 10% shaft diameter approach. The ultimate resistances for these drilled shafts and bored piles were also predicted using methods based on the design code from North America (United States, Canada), Europe, and Asia (Japan). The pile resistances determined from field load-settlement tests were compared with those calculated using the design codes. The comparisons show that most design codes predict a conservative resistance for drilled shafts and bored piles. However, in the case of drilled shafts, we find that some of the design codes can over-predict the resistance and, therefore, should be applied cautiously. This research also shows that the t-z method can be successfully used to predict the ultimate resistance and the load transfer mechanism for a single pile.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.336-342
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• 2014

Shear strengths of reinforced high strength concrete beams without web reinforcement are studied with experimental analysis of 10 specimen with 2.4 shear span-to-depth ratio (a/d) beams for 4 stages of concrete compressive stength over 60MPa comparing ultimate loads and shear stresses of ACI363R and KCI code equations. Expecially, concrete compressive strengths used in shear design were essentially limited to 10,000 psi (69MPa) by ACI363R and KCI Code. The modified Code equation's shear stresses of the specimen without the limit are compared with test results. The comparison between the modified exist Code equations results and test results are expected to show an available scope to apply in construction field and to give considerations of design and contraction.