• Journal of the Korean Geotechnical Society
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• v.37 no.1
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• pp.29-41
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• 2021

Although underground works are essential to use underground spaces in urban areas efficiently, various damages caused by constructions have often occurred, making them major social problems. Since 2018, it is stipulated in the Special Act on Underground Safety Management that appropriate construction methods must be used in the design stage to prevent various damage cases. This Special Act includes establishing an area subject to underground safety impact assessment, analysis of ground and geological status, review of effects caused by changes in groundwater, review of ground safety, and establishment of measures to secure underground safety. This study area consists of various strata in order of landfill, sedimentary silt, sedimentary sand, sedimentary gravel, weathering zone, and foundation rock. Also, the slurry wall, a highly rigid underground continuous wall, was chosen as a construction method to consider high water table distribution and minimize the influence of the surroundings in this area. However, ground subsidence occurred on the road nearby in December 2019 due to the inflow of loosening soil to the construction area. Thus, several types of site investigations were conducted to suggest an appropriate analysis method and to find out loosed ground behavior and its area for the subsided site. As a result, new design soil properties were re-calculated, and the reinforcement measures were proposed through analytical verification.

• The Journal of Fisheries Business Administration
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• v.39 no.1
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• pp.87-114
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• 2008

The cultured tuna production which has suddenly expanded at the short time and the demand for it attract attention. Farming mode, distribution transactions, change of the market (domestic and international) and the price trend are reviewed from the Japan's position which is the biggest consuming country. This paper tries to describe the current status of the food system related to the cultured tuna. Japanese government began the development of the tuna culture technology in 1970. It was by the Fisheries Agency's project. Kinki University which is the large scale private university in Japan participated in the project. After that, 32 years have passed. Kinki University established the full farming of the bluefin tuna in August, 2002. On the other hand, in 1974, one Japanese private enterprise began its tuna farming business in Canada. Kinki University gave this company technical cooperation. Also, in the early stages of the 90s, as for the policy of the overseas fishery cooperation foundation, it supported the tuna farming business in Australia. It is very clear to understand that the long-term technological-development has supported the take-off scene of the tuna culture business not only in foreign countries but also in Japan. The total shipment scale of the cultured tuna expanded very much within about 10 recent years. However, the decrease of the wild tuna catch, the reinforcement of the fisheries regulation and the tuna body to dwarf are remarkable now. Under the condition as the mentioned above, Japan's tuna consumption, especially, in the market at the fatty meat of tuna of the cultured tuna is building up firm status. At present, the Mediterranean Sea coastal countries, Australia, Mexico and Japan have the tuna farming sites. Australia farms the southern bluefin tuna. The others do the bluefin tuna. About for 3 years, Japan farms the juvenile of the tuna. The global production areas are as follows. 8 coastal countries of the Mediterranean Sea; 18,000 tons (61 % of the cultured tuna quantity in foreign countries), Mexico; 4,500 ton (15%), Australia; 7,000 tons (24%). In 2003, Japan has 32 managements and 39 offices for tuna farming. In Japan, Kyushu and Okinawa district, the share shows itself as 80 % of the domestic production quantity. Especially, the share of Amami-oshima Island in Kagoshima Prefecture exceeds 60 %. Therefore, this island has the maximum production scale of Japan. The amount of supply of BT and SBT was 56,000 tons in 2004. In Abroad, the tuna farming business forms a fixed connection between the importer and the wholesaler which have their office in Japan. In the field of the capital composition, the payment in advance, transaction and the way of settlement, each maintains their fixed relation. The market conditions of the cultured tuna are supported by "the decline of price level" and "the expansion of the general public consumption segment". These lead a team merchandising, and it is supported by the fixed business connection of each. This makes the profit of each business which are on the cultured tuna distribution. However, they have competition on the power balance among them.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.95-105
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• 2005

Generally, a modified version of limit equilibrium method can be used to evaluate a slope stability of the geosynthetic reinforced soil slopes. In most cases, resisting effects of geosynthetic reinforcement are dealt with considering an increased shear strength on the potential slip surface. However, it is not clear that the methods satisfy all three equilibrium equations. As we know, the pattern of normal stress distribution along the slip surface is the key factor in calculating the safety factor of slopes. In this study, the new slope stability analysis method in which not only reinforcing effects of geosynthetics can be considered but also all three equilibrium equations can be satisfied was proposed with assuming the normal stress distribution along the slip surface as quadratic curve with horizontal $\chi-coordinate$. A number of illustrative examples, including published slope stability analysis examples for the reinforced and unreinforced soil slopes, loading test of large scale reinforced earth wall and centrifuge model tests on the geotextile reinforced soil slopes, were analyzed. As a result, it is shown that the newly suggested method yields a relatively accurate factor of safety for the reinforced and unreinforced soil slopes.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.105-113
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• 2010

This study is for the preservation plan of the tradition space which is performed by the damage status analysis through performing the value assessment. Especially, it is an experimental study for finding the process and methods by analyzing the major element for the value assessment of the selected object's damage status through the expert group who are systematized in their interest to conserve the traditional structure in traditional space. For that purpose, this study should be performed by the fundamental understanding of the physical property of the Supyo-bridge and the condition of the selected site's environment. Meanwhile, this study has been done that 'map of the damage status distribution' for making records of damage status of the Supyo-bridge on the property utilized field measurement adapted by photogrammetry and assessment guidelines, which are for investigation on damage status of objects that are standardized 'Raccomandazioni Normal' which could be said construction culture assets management guidelines of Italian government. As the result of investigation, damage status of each part in the Supyo-bridge was mostly composed of damage by sediment and corrosion and in case of 9 damage types including corrosion, in consideration of physical and chemical properties and distribution status of those elements, it is made an judgement that is not working as a threatened factor regarding security of the Supyo-bridge. On the contrary, for the improvement landscape, in case of 'Thermoclastism' phenomenon observed in 'upper floor', 'Myungae stone' and 'bridge pier' is that when taking it into consideration that is widely distributed concentrated on the bridge pier, surface reinforcement job along with elimination of damage part will be judged to be requested for earliest treatment.

• Korean Journal of Social Welfare Studies
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• v.49 no.1
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• pp.51-83
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• 2018

This study examines whether the widening gap between income groups is worsening in the distribution of time use, similar to the worsening of income distribution after the IMF. To do this, we conducted multilevel analysis (HLM) on six countries including France, the Netherlands, Spain, the United Kingdom, the United States and Korea. The results of the analysis are as follows. First, in all countries, low income groups have a longer paid working time and shorter leisure time. Second, the low income groups in Korea have the longest paid work time and the shortest leisure time, the lowest level of work-leisure balance, and this aspect has not recovered since the IMF. Third, as the result of multilevel analysis, the lower the household income, the more time paid labor increased and the work-leisure balance decreased. Fourth, while average annual working hours increase paid working time, the expansion of family policy expenditure, redistribution policy and income maintenance policy has reduced it. Fifth, the annual average working hours decreased the work-leisure balance, but the family policy expenditure, the redistribution policy and the income guarantee policy increased the work-leisure balance. The significance of this study is that after the IMF, not only the income distribution but also the inequality among the income class in time use has deepened. Based on the results of the research this study suggests the reinforcement of labor time regulation, the activation of parental leave system, the realization of the income replacement rate, the expansion of the policy related to income redistribution, and the complementary development of the income guarantee and the time guarantee policy as the policy intervention strategy that restructures time.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.282-287
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• 2009

Rod-shaped particle reinforced $LiAlO_2$ matrices for MCFC were fabricated by an aqueous tape-casting technique. The hydrolysis reaction and agglomeration of $\gamma-LiAlO_2$ particles in aqueous slurries were inhibited by additions of $LiOH{\cdot}H_2O$ and glycerin to the aqueous $\gamma-LiAlO_2$ slurry. The tape-casting, performed using the aqueous slurry containing protein albumin, was fast and led to an effective drying at casting temperature range of $60{\sim}65^{\circ}C$. The strength of the particle reinforced matrix was improved about 4 times compared to that of matrix without reinforcement. Pore size distribution ($0.1{\sim}0.4{\mu}m$) and porosity ($50{\sim}60%$) of the reinforced matrices were determined to be appropriate for the MCFC matrix. The aqueous tape casting process is not only environmental-friendly but also efficient for fabricating MCFC matrices compared to non-aqueous tape casting.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.115-120
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• 2011

The strength of reinforced concrete members has uncertainty from material properties of, concrete and reinforcements, section dimensions, and construction errors and so on. The accurate evaluation of these uncertainties is necessary to assure the reasonable safety. The uncertainties should be taken into account in design using structural reliability theory which requires probabilistic models for such uncertainties. In current Korean design code, most reliability evaluations were performed based on foreign data because of lack of local data. In this paper, the probabilistic models for yield strength of reinforcements were developed based on local data. The effects of various factors, nominal yield strength, diameter of reinforcements, and companies, on the models are also examined. According to data analysed, the effects of those factors are not significant. The probability model for yield strength of reinforcements in Korea can be expressed with Beta distribution based on collected data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2406-2413
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• 2014

Since clear span-to-depth ratio is used to define what is so called a deep beam, it is an important parameter ratio for study about deep beam. Deep beams can be designed by flexure design method, and shear provided by concrete ($v_c$) and by steel ($v_s$) for deep flexure members are provided in ACI 318-99 [1]. But in later version of ACI (from ACI 318-02) it is not provided and deep beams shall be designed either by taking into account nonlinear distribution of strain or by Appendix A of Strut-and-Tie Models (STM). The trend of deep beam design seems to be familiar with strut-and-tie model, but ACI traditional design is not forgotten. By comparing these two method, there should a point which definitely explain the different between the two methods. In this study, 68 samples result of steel, after reinforcement arrangement, are taken to be analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2509-2518
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• 2013

Augmented reality (AR) technology visualizes a real type object that cannot simulate in virtual reality technology by overlapping a virtual object and real object in a computer system. This study suggests a methodology and prototype system for applying AR system to rebar distribution work in a civil engineering project. Rebar work in civil engineering project is a representative activity that is progressed by empirical approach of skilled labor rather than formalized manual. AR technology improves the constructability of rebar work because AR tool can identify missing rebars and different rebars comparing with the drawings. AR system developed in this study can enhance the understanding of rebar work using 3D modeling with real image of construction site and save construction cost by reducing reconstruction work.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.617-627
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• 2011

This paper presents the results of analytical simulation of shake-table responses of a 1:5 scale 10-story reinforcement concrete(RC) residential building model by using the PERFORM-3D program. The following conclusion are drawn based on the observation of correlation between experiment and analysis; (1) The analytical model simulated fairly well the global elastic behavior under the excitations representative of the earthquake with the return period of 50 years. Under the design earthquake(DE) and maximum considered earthquake(MCE), this model shows the nonlinear behavior, but does not properly simulate the maximum responses, and stiffness and strength degradation in experiment. The main reason is considered to be the assumption of elastic slab. (2) Although the analytical model in the elastic behavior closely simulated the global behavior, there were considerable differences in the distribution of resistance from the wall portions. (3) Under the MCE, the shear deformation of wall was relatively well simulated with the flexural deformation being overestimated by 10 times that of experiment. This overestimation is presumed to be partially due to the neglection of coupling beams in modeling.