• The Journal of Engineering Geology
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• v.7 no.3
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• pp.191-205
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• 1997

Measurements on subsurface movement of the Songsanri tomb site including the Muryong royal tomb was conducted using a tiltmeter system for the period of 15 months form July 7, 1996 to September 30, 1997. Two coordinate tilt monitoring data shows the biggest movement rate of 2.3mm/m/yr toward south in the frontal wall(N-S tilt) of the Muryong royal tomb. Southward tilting of bricks above the southern fire place in the western wall of the Muryong royal tomb is a proof of southward tilting of the royal tomb since its excavation in 1971. The eastern wall of the Muryong royal tomb is also tilting toward inside the tomb with the rate of 1.523mm/m/yr. Furthermore, tilting rate of wall increases twice in rainy season. It is interpreted tbat infiltration of water into the tomb and nearby ground in rainy season results in dangerous status for the safety of tomb structure. On the whole, normal component tilting of the walls of the 5th tomb is large than its shear component. It shows a small displacement toward one direction without no abrupt change in its direction and amount of tilting. The tilting rate of walls of the 6th tomb is about 8.8mm/m/yr in the dry season which is much bigger than those of other tombs in rainy season. Deformation events of walls of the tombs are closely related to amount of precipitation and variation of temperature. In comparison with different weather conditions, tilting is much bigger during the period of rainy weather than sunny weather. It is interpreted that rainwater flew into the turm through faults and nearby ground. High water content in nearby ground resulted strength of ground. The tilting event of walls shows a hysterisis phenomenon in analysis of temperature effect on tilting event. The walls tilt rapidly with steep rising of temperature, but the tilted walls do not come back to original position with temperature falling. Therefore, a factor of steep increase of the temperature must be removed. It means the tomb have to be kept with constant temperature. The observation of groundwater level using three boreholes located in construction site and original ground represented that groundwater level in construction site is higher than that of original ground during the rainy season from the end of June to August. It means that the drainage system of the Muryong royal tomb is worse than original ground, and it is interpreted that the poor drainage system is related to safety of tomb structure. As above mentioned, it is interpreted that artificial changes of the tomb environment since the excavation, infiltration of rainwater and groundwater into the tomb site and poor drainage system had resulted in dangerous situation for the tomb structure. According to the result of the long period observation for the tomb site, it is interpreted that protection of the tomb site from high water content should be carried out at first, and the rise of temperature by means of the dehumidifier inside the tomb must be removed.

• Journal of the Korea Concrete Institute
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• v.26 no.5
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• pp.651-660
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• 2014

Structural members using ultra high strength concrete which usually used with steel fiber is designed with guidelines based on several investigation of SF-RPC(steel fiber reinforced reactive powder concrete). However, there are not clear design method yet. Especially, SF-RPC member should be casted with steam(90 degree delicious) and members with SF-RPC usually used with precast members. Although the most important design parameter is development method between SF-RPC and steel reinforcement(rebar), there are no clear design method in the SF-RPC member design guidelines. There are many controversial problems on safety and economy. Therefore, in order to make design more optimum safe design, in this study, we investigated bond stress between steel rebar and SF-RPC according to test. Test results were compared with previously suggested analysis method. Test was carried out with direct pull out test using variables of compressive strength of concrete, concrete cover and inclusion ratio of steel fiber. According to test results, bond stress between steel rebar and SF-RPC increased with increase of compressive strength of concrete and concrete cover. Increasing rate of bond stress were decrease with increase of compressive strength of SF-RPC and concrete cover significantly. 1% volume fraction inclusion of steel fiber increase the bond stress between steel rebar and SF-RPC with two times but 2% volume fraction cannot affect the bond stress significantly. There are no exact or empirical equations for evaluation of SF-RPC bond stress. In order to make safe bond design of SF-RPC precast members, previously suggested analysis method for bond stress by Tepfers were evaluated. This method have shown good agreement with test results, especially for steel fiber reinforced RPC.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.347-365
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• 2020

In order to resolve traffic problems in urban areas and to increase the area of green spaces, tunnels in downtown areas are being increased. Additionally, the application of large port smoke extraction ventilation systems is increasing as a countermeasure to smoke extraction ventilation for tunnels with high potential for traffic congestion. It is known that the smoke extraction performance of the large port smoke extraction system is influenced not only by the amount of the extraction flow rate, but also by various factors such as the shape of the extraction port (damper) and the extraction air velocity through a damper. Therefore, in this study, the design standards and installation status of each country were investigated. When the extraction air flow rate was the same, the smoke extraction performance according to the size of the damper was numerically simulated in terms of smoke propagation distance, compared and evaluated, and the following results were obtained. As the cross-sectional area of the smoke damper increases, the extraction flow rate is concentrated in the damper close to the extraction fan, and the smoke extraction rate of the damper in downstream decreases, thereby increasing the smoke propagation distance on the downstream side. In order to prevent such a phenomenon, it is necessary to reduce the cross-sectional area of the smoke damper and increase the velocity of passing air through the damper so that the pressure loss passing through the damper increases, thereby reducing the non-uniformity of smoke extraction flow rate in the extraction section. In this analysis, it was found that when the interval distance of the extraction damper was 50 m, the air velocity passing through damper was 4.4 m/s or more, and when the interval distance of the extraction dampers was 100 m, the air velocity passing through damper was greater than 4.84 m/s, it was found to be advantageous to ensure smoke extraction performance.

• Clean Technology
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• v.18 no.4
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• pp.379-389
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• 2012

Environmental issues are being paid more attention due to income growth, urban overcrowding, and population growth in Korea. Among the various environmental problems, odor damage is the one of the serious factors. To take example for food waste combination treatment in Su-young wastewater treatment plant in Busan, many complaints occurred because this plant locate around residential areas. The purpose of this work is not only to analyze odorous elements and their contributions but also to evaluate odor quotient (OQ), sum of odor quotient (SOQ), and treatment efficiency of bio-filter. The results of dilution sensory test of complex odor, grinder, leachate, hopper indicated higher order complex odors happen in July and August. The main odorous elements consisted of hydrogen sulfide, ammonia, methly mercaptan and acetaldehyde, which were analyzed by instrumental detection method, and methyl mercaptan was exceeded over 3,571 times of threshold. In addition, result of contribution of odor was methyl mercaptan (49.95 to 59.08%), hydrogen sulfide (20.43 to 29.27%), trimethylamine (8.82 to 13.42%) and acetaldehyde (9.17 to 11.35%). Other facilities were compared with the contribution of the odor using OQ and SOQ during the process. Sulfur compounds, acetaldehyde, and trimethylamine are high contribution of odor using OQ as well as odor intensity of grinding process is highest. As a result, sulfur compounds (e.g., methyl mercaptan and hydrogen sulfide) are highest for OQ and SOQ of grinding process is highest as 7,067. The removal efficiency of deodorization equipment was more than 90.00% in ammonia and amines, but the average efficiency of sulfur compounds was 53.51%. Thus, this facility is more higher contribution of acetaldehyde and trimethylamine than other treatment facilities. And food waste treatment in environmental area needs to consider appropriate capacity and refers to other bio-filter operating conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.290-307
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• 2011

Acrolein is highly toxic and may be formed from carbohydrates, vegetable oils, animal fats and amino acids during heating of food. In the present study, we investigated adults' intake level of cooked meat using high temperature cooking method such as pan frying or grilling directly over an open flame and indirect fire using pan. The 925 adults (438 men and 487 women) participated in this nationwide survey. According to the result of frequency intake of cooked meat at high temperature, the most frequently consumed cooked meat at high temperature was fried chicken, followed by indirect cooking-samgeybsal and directly grilled fish and mackerel pike among twenty five kinds of cooked meats and foods, which were eaten more than three times per month. The woman consumed direct grilled fish and mackerel pike more than three times per month, while the man consumed samgeybsal, pork cutlet, and fried chicken once per week. The order of total intake amount of cooked meat per adult for a year is 10.3 kg of fried chicken (man 13.1 kg, woman 8.04 kg), 6.7 kg of samgeybsal (man 9.4 kg, woman 4.7 kg) and 5.1 kg of jeyukbockeum (man 7.0 kg, woman 3.6 kg). The results of present study suggest that adult must realize the risk of consuming cooked meat at high temperature and the need for education for proper dietary habit to prevent geriatric diseases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.113-125
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• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.662-671
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• 2015

As the type of Hazardous and Noxious Substances(HNS) becomes various and the transport volume of HNS increases, HNS spill incidents occur frequently on land and the sea. In view of various damages to human lives and properties by HNS spills, it is necessary to educate and train professional personnel in preparation for and response to potential HNS spills. This study shows the current state of response systems and education courses against HNS spill incidents on land and the sea to compare those with each other between land and sea in Korea. Incident command system on land are basically similar to that at sea, but leading authority which is responsible for combating HNS spills at sea is changeable depending on the location of HNS spill, as it were, Korea Coast Guard(KCG) is responsible for urgent response to HNS spill at sea, while municipalities are responsible for the response to HNS drifted ashore. Education courses for HNS responders on land are established at National Fire Service Academy(NFSA), National Institute of Chemical Safety(NICS), etc., and are diverse. Education and training courses for HNS responder at sea are established at Korea Coast Guard Academy(KCGA) and Marine Environment Research & Training Institute(MERTI), and are comparatively simple. Education courses for dangerous cargo handlers who work in port where land is linked to the sea are established at Korea Maritime Dangerous Goods Inspection & Research Institute(KOMDI), Korea Port Training Institute(KPTI) and Korea Institute of Maritime and Fisheries Technology(KIMFT). Through the comparison of education courses for HNS responders between land and sea, some recommendations such as extension of education targets, division of an existing integrated HNS course into two courses composed of operational level and manager level with respective refresh course, on-line cyber course and joint inter-educational institute course in cooperation with other relevant institutes are proposed for the improvement in education courses of KCG and KOEM(Korea Marine Environment Management Corporation) to educate and train professionals for combating HNS spills at sea in Korea.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.6
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• pp.49-62
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• 2018

The purpose of this study is to develop an assessment index for the selection of promising start-ups, which will enhance the efficiency of program that support start-ups. In order to develop assessment models for selecting start-ups, three major research steps were conducted. First, this study attempted to theoretically redefine the assessment index from the perspective of the Balanced Scorecard (BSC) through a literature review. Second, major assessment index were derived using Delphi technique for experts in start-up areas. Third, weights were derived by applying AHP technique to calculate the importance of each index. The results of this study are summarized as follows. First, this study attempted to apply the assessment model for selecting start-ups from the Balanced Scorecard (BSC) view through the previous study review. Second, the final major questions were derived with sufficient opinions collected and structured survey of leading start-up experts in areas related to research subjects and elicited the most representative questions. Third, the results of applying the weights of the main selected assessment index, commercialization viewpoint is the most priority, followed by market view, technology development viewpoint, and organizational capability viewpoint. In the middle section, th ability to make products in the commercialization viewpoint, market competitiveness in the market, product discrimination capacity in the technology development perspective, and the ability of the entrepreneur in the organizational capacity perspective were important. Overall important items were found to be in the order of the capabilities of entrepreneurs, market competitiveness, product fire capability, and product discrimination. The importance of small items was highest priority for comparative excellence of competing products, and the degree of marketability, capacity of entrepreneurship, ability to raise capital, desire for entrepreneurship, and passion were shown. The results of this study presented a conceptual alternative to the preceding study on the development of existing selection assessment indexes. And it provides meaningful and important implications as an attempt to develop more sophisticated indicators by overcoming the limitations of empirical research on only some of the evaluation metrics.