• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.730-736
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• 2019

The demand for natural gas, which is considered an environmentally friendly energy source, is increasing, and at the same time, the market share of large pipelines for natural gas supply is increasing continuously. On the other hand, the corrosion of such large pipelines reduces the efficiency of natural gas transportation. Therefore, this study aims to establish a strategy for securing the patent rights of related technologies through quantitative analysis of patents on energy-independent high-efficiency corrosion prevention technology for large-scale pipelines for natural gas supply. In this patent technology trend study, Korean, US, Japanese, and European patents filed, published, and registered by June 2018 were analyzed, and a technical classification system and classification criteria were prepared through expert discussion. To use fuel cells as an external power source to prevent the corrosion of natural gas large-scale pipelines, it is believed that rights can be claimed using an energy control system and methods having 1) branch structures of pipeline and facility designs (decompressor/compressor/heat exchanger) and 2) decompression/preheating and pressurization/cooling technology of high pressure natural gas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.112-117
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• 2017

Interest in the development of renewable energy sources has been increasing over the past 10 years and the west coast of Korea is one of the most favorable regions for tidal power. Barrage type tidal power is representative of the experience of installation and operation of such power sources for long periods. However, future projects for barrage type energy sources are either delayed or closed due to their environmental impact. For this reason, we applied a new tidal power technology with minimized environmental impact to a candidate area in the west coast and then analyzed its feasibility. The new tidal power technology is called Dynamic Tidal Power (DTP). Because its verification is impossible both in the laboratory and field, a numerical model is used for the evaluation of DTP. This new technology produces tidal power by means of the phase difference caused by diffraction on both sides of a dike built tens of km away from the coast. Because DTP is theoretically able to almost double the tidal range, it is expected to be applicable to even a small tidal area. Unlike the barrage type, it has the advantage of reducing the environmental impact by not enclosing the sea water. The west coast of Korea is close to the metropolitan area and has a high tidal range and, thus, it is thought to be a suitable candidate for tidal power.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.39-46
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• 2017

The experimental research was conducted to evaluate the adhesive performance of surface finishing material with primer based on silane(primer). For this purpose, concrete specimens with compressive strength of 18, 30, 50 MPa were made and cured in water condition ($20{\pm}2^{\circ}C$) for 28 days. A primer was applied on the age of 28 days and evaluated according to based on the curing age of the surface finishing material. Moreover, the mortar specimen also made and tested as per KS F 4937 for compared with concrete-based test results. Test results indicated that the adhesive strength of specimens with primer exhibit similar than that of specimens without primer. Also, the adhesive performance improved with increasing in curing age and compressive strength. The correlation between compressive and adhesive strength of mortar and concrete specimens showed similar trend. It was noted that there is no significant effects of primer on adhesive performance of surface finishing material, thus use of primer has superior potential for solving durability problem of concrete slab surface.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.53-60
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• 2017

Fly ash(FA) which is a byproduct in the coal combustion in thermal power plant contributes to pore structure densification due to pozzolanic reaction, and this leads to long-term strength development and excellent resistance to chloride penetration. In the work, compressive strength and chloride resistance in OPC(Ordinary Portland Cement) and FA-based concrete are evaluated, and the relationships are investigated considering ages. For the work, 3 different W/B (Water to Binder) ratios of 37%, 42%, and 47% are prepared, and 3 substitution ratio of fly ash(0%, 30%, and 50%) are considered as well. At the age of 28 days and 180 days, test results of compressive strength, diffusion coefficients based on Tang's method, and passed charges referred to ASTM C 1202 and KS F 2711 are obtained. With increasing replacement ratio of FA and decreasing W/B, the resistances to chlorides(diffusion coefficient and passed charge) are improved, and the results at the age of 180 days decrease to only 15% level at the age of 28 days due to pozzolanic reaction in FA 50 mixture, which shows that resistance to chloride is much dependent on age effect than strength development. After 180 days, more clear linear relationships are observed between strength and resistance to chloride.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.70-77
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• 2012

The Ladle Furnace Slag, about 20% of the electric arc furnace slag, has high content of free CaO and free MgO, which generates the expansion collapse by hydration reaction. Although many researchers have been endeavoring to recycle the EAF reducing slag in construction fields, there is not found the effective recycling method up to now. However, the LFS(Ladle Furnace Slag) contains mineral composition of the system of calcium aluminate with high-reactivity. Therefore, it is possible to developed the quick setting property and the high strength at the early age by the rapid cooling. This study aimed to check the reactive minerals and predict the reactivity with water on the LFS discharged from different steel product plants. The test results show that many types of LFS has hydration reactivity and can use in construction field as a inorganic binder with the rapid setting property.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.1-9
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• 2014

In this paper, $CO_2$ amount is evaluated considering repairing timing and unit $CO_2$ amount per repair method including various stage of material manufacturing, moving, and construction. Four mix proportions with mineral admixture are considered and repairing timing/numbers are simulated based on the results from Life 365 which can handle chloride penetration. Furthermore two repair methods (simple cover concrete replacement and replacement with electro-chemical method for removing chloride content) are considered and the related $CO_2$ emissions are evaluated. From the study, the case with high W/B (water to binder ratio) ratio shows smaller $CO_2$ emission in construction stage but it increases more rapidly with increasing number of repair. $CO_2$ emission considering electro-chemical method greatly increases with the increasing unit $CO_2$ for the repairing method. The numbers of jumping step (repairing number) are evaluated to be 9 for WB37-OPC, 18 for WB50-OPC, 4 for WB40-SG, and 7 for WB47-SG respectively. RC structures with the longer maintenance free period are evaluated to be advantageous for saving $CO_2$ emission.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.663-668
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• 2000

To develop natural intermediate flavoring substances, optimal processing conditions and qualities for two stage enzyme hydrolysate (TSEH) from low-utilized small longfinned squid were investigated. The optimal conditions for TSEH method were found as digestion with Alcalase (0.2% w/w-sample, pH 8.0) at 55$^{\circ}C$ 3 hours at the 1st stage and with Neutrase (exo-peptidase, 0.2% w/w-sample, pH 6.0) at 45$^{\circ}C$ for 2~3 hours at the 2nd stage. Among the method of water extract, autolytic extract and various kinds yields, transparency and organoleptic taste. From the results of chemical experiments and sensory evaluation, longfinned squid TSEH is flavorable as the natural intermediate taste-active substances for fisheries products such as soup base, squid-taste pasty and snacks.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.651-656
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• 2007

Fish-frames which are left after obtaining fillets or muscle during fish processing, consist of useful food components such as muscle, collagen, calcium, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This study was carried out to prepare snack using flatfish frame and also to elucidate food component characterization of the snack. The results of heavy metal and volatile basic nitrogen (VBN) content suggested that flatfish frame was a suitable material for preparing snack. The optimal addition ratio of flatfish frame to mix was 3% for preparing snack according to the results of VBN content, water activity and sensory evaluation. The major fatty acids of the snack with 3% flatfish frame (SFF) were 16:0 and 18:0 as saturates, 18:1n-9+7 as monoenes, and 18:2n-6 and 18:3n-3 as polyenes, while EPA and DHA were contained in small amount SFF. Total amino acid content (9,281.9 mg/100 g) of the SFF was higher than that of the snack without flatfish frame (7,791.3 mg/100 g) and the major amino acids were aspartic acid, glutamic acid, proline and leucine. The calcium and phosphorus contents of SFF were 492.3 mg/100 g and 270.3 mg/100 g, respectively. The Ca/P of SFA was 1.82 which is a good ratio for the absorption of calcium. The SFF was superior in total amino acid, calcium and phosphorus contents compared to the snack without flatfish frame.

• Environmental and Resource Economics Review
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• v.18 no.2
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• pp.217-239
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• 2009

As gas hydrate is recently emerging as a new energy source to solve environmental and exhaustion problems caused by fossil energy, Korea is working on a gas hydrate development project under a 10-year plan from 2005 to 2014. Gas hydrate is expected to have a big effect on the economy and society of Korea, which is largely depending on energy imports besides water energy and atomic energy. However, it is uncertain whether the project will produce successful results. Thus, it is very important to improve its validity and to propose effective execution strategies by evaluating the value of the project in advance. Thus, this study intended to include new information, which had not been evaluated in existing methods, and to reduce biases or errors in value evaluation results by applying a fuzzy risk analysis to the real option model in order to evaluate the value of a gas hydrate development project. It is advantageous that the real option model based on the fuzzy risk analysis modelizes the vagueness and inexactness of intangible element judgment into an appropriate language scale so as to evaluate these elements clearly and integrate them with estimated financial performance results. The application of the fuzzy risk analysis makes it possible to conduct an analysis by dissolving a decision-making issue with complicated and various attributes into several simplified problems. With the continuing high oil prices and today's demand of clean energy, the necessity of energy resources and technology development projects keeps growing. Amid this situation, it is expected that these study results will contribute to proposing a guideline not only for gas hydrate projects but also for policy decision-making related to future energy industries.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.261-268
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• 2018

The study used the simplified flooding analysis model, SIMOD, to distribute the total flood discharge by time, so research on flooding in urban areas can be conducted. The conventional flooding analysis models have limitations in constructing input data and take a long time for analysis. However, SIMOD is useful because it supports rapid decision-making process using quick modeling based on simple hydrological data, such as topography and inflow flood of the study area, to analyze submerged routes formed by flooding. Therefore, the study used the SIMOD model to analyze flooding in urban areas before conducting a comparative study with the outputs from FLO-2D, which is one of the conventional flooding analysis models, to identify the model's applicability. Seongseoje was selected as the study area, as it is located downstream the Geumho river where streams flow in the adjacent areas, and dikes are high enough to apply the "Overflow and Break" scenario for urban areas. With regard to topography, the study applied DEM data for the conventional flooding analysis and DSM data to represent urban building communities, distribution of roads, etc. Input flood discharge was calculated by applying the rectangular weir equation under the bank and break scenario through a 200-year return period of a design flood level. Comparative analysis was conducted in a flooded area with a simulation time of 1-24 hours. The time for the 24-hour simulation in SIMOD was less than 7 minutes. Compared with FLO-2D, the difference in flooded areas was less than 20%. Furthermore, the study identified the need for topography data using DSM for urban areas, as the analysis result that applies DSM showed the influence of roads and buildings.