• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.590-596
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• 2019

Numerous deaths and substantial property damage have occurred recently due to frequent disasters of the highest intensity according to the abnormal climate, which is caused by various problems, such as global warming, all over the world. Such large-scale disasters have become an international issue and have made people aware of the disasters so they can implement disaster-prevention measures. Extensive information on disaster prevention actively has been announced publicly to support the natural disaster reduction measures throughout the world. In Japan, diverse developmental studies on disaster prevention systems, which support hazard map development and flood control activity, have been conducted vigorously to estimate external forces according to design frequencies as well as expected maximum frequencies from a variety of areas, such as rivers, coasts, and ports based on broad disaster prevention data obtained from several huge disasters. However, the current reduction measures alone are not sufficiently effective due to the change of the paradigms of the current disasters. Therefore, in order to obtain the synergy effect of reduction measures, a study of the establishment of an integrated system is required to improve the various disaster prevention technologies and the current disaster prevention system. In order to develop a similar typhoon search system and establish a disaster prevention infrastructure, in this study, techniques will be developed that can be used to forecast typhoons before they strike by using artificial intelligence (AI) technology and offer primary disaster prevention information according to the direction of the typhoon. The main function of this model is to predict the most similar typhoon among the existing typhoons by utilizing the major typhoon information, such as course, central pressure, and speed, before the typhoon directly impacts South Korea. This model is equipped with a combination of AI and DNN forecasts of typhoons that change from moment to moment in order to efficiently forecast a current typhoon based on similar typhoons in the past. Thus, the result of a similar typhoon search showed that the quality of prediction was higher with the grid size of one degree rather than two degrees in latitude and longitude.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.1
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• pp.15-29
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• 2020

Recently, the incidence of flooding in Korea has decreased by the measures by central and local governments, however the scale of damage is increasing due to the improvement of living standard. One of the causes of such flood damage is natural causes such as rainfall exceeding the planned frequency of flood control under climate change. In addition, there are artificial causes such as encroachment of river spaces and management problems in upstream basins without consideration of downstream damage potential by regional development flood. In this study, in order to reduce the inundation damage caused by flooding of river, the situation at the time of inundation damage was reproduced by the detailed topographic data and 2D numerical model. Therefore, the effect of preparing various disaster prevention measures for the lowland was simulated in advance so that quantitative evaluation could be achieved. The target area is Taehwa river basin, where flooding was caused by the flooding of river waters caused by typhoon Chaba in October 2016. As a result of rainfall-discharge and two-dimensional analysis, the simulation results agree with the observed in terms of flood depth, flood arrival time and flooded area. This study examined the applicability of hydraulic analysis on river using two-dimensional inundation model, by applying detailed topographic data and it is expected to contribute to establish of disaster prevention measures.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.45-56
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• 2007

As function and scale of the transit center get larger, the efficient guidance system in the transit center is essential for transit users in order to find their efficient routes. Although there are several studies concerning optimal path for the road, but insufficient studies are executed about optimal path inside the building. Thus, this study is to develop the algorithm about optimal path for car owner from the basement parking lot to user's destination in the transfer station. Based on Dijkstra algorithm which calculate horizontal distance, several factors such as fatigue, freshness, preference, and required time in using moving devices are objectively computed through rank-sum and arithmetic-sum method. Moreover, optimal public transportation is provided for transferrer in the transfer station by Neuro-Fuzzy model which is reflected on people's tendency about public transportation mode choice. Lastly, some scenarios demonstrate the efficiency of optimal path algorithm for pedestrian in this study. As a result of verification the case through the model developed in this study is 75 % more effective in the scenario reflected on different vertical distance, and $24.5\;{\sim}\;107.7\;%$ more effective in the scenario considering different horizontal distance, respectively.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.418-427
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• 2004

Recently, urban planning with consideration of urban climate, represented by the concept of urban ventilation lane is widely practiced in many countries. The concept of urban ventilation lane is mainly aimed to improve the thermal comfort within urban area in summer season. It has also the aim to reduce the urban air pollution by natural cold air drainage flows which are to be intensified by a suitable alignment of buildings as well as use zonings based on scientific reasons. In this study, the prevailing wind ventilation lane of a local wind circulation and around Daegu for a typical summer days was investigated by using a numerical simulation. The transport of air pollutants by the local circulation winds was also investigated by using the numerical simulation model, the RAMS (Reasonal Atmospheric Model System).The domain of interest is the vicinity of Daegu metropolitan city (about 900 km2). The horizontal scale of the area is about 30 km. The simulations were conducted under a late spring synoptic condition with weak gradient wind and almost clear sky. From the numerical experiment, the following three conclusions were obtained: (1) The major wind passages of the local circulation wind generated by radiative cooling over the representative mountains of Daegu (Mt. Palgong and Mt. Ap) were found. The winds blow down along the valley axis over the eastern part of Daegu as a gravity flow during nighttime. (2) At the flatland, the winds blow toward the western part of Daegu through the city center. (3) As the results, the air pollutants were transported toward the western part of Daegu by the winds during nighttime.

• The Journal of Fisheries Business Administration
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• v.32 no.1
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• pp.15-39
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• 2001

The study, using the input-output analysis of 402 industrial sectors by Bank of Korea(BOK) and the resulting outcomes of price model, aims to evaluate the spillover effects the international fluctuations in crude oil prices have on the commodities prices and consequently, analyse the management and profitability of the offshore fisheries in Korea. At present, the fisher men are provided with tax-free oils for their fishing operations as specified under the Special Tax Treatment Control Law. However, the exhaustion of marine resources and new international fisheries agreements, which resulted in the loss of fishing grounds, made the stable catch even more unpredictable and the hike in the price of the international crude oil would have adverse effects on the fishing industry. The study revealed that the increasing rise in the price of crude oil would exert sweeping spillover effects on other industry sectors in general and accordingly, lead to a poorer performance by fisheries. The price spillover coefficients for the diesel oil was 0.6026, which would translate into the 42.6% increase in the prices of oil when the increase ratio of 73.3% for the base crude oil was applied based on the calculation methods employed in the study. This in turn increased the ratio of diesel oil required in the offshore fisheries from 23.3% to 16.6%, diminishing the ratio of current net profits to minus 2.0% from 4.2% otherwise. By fishing type, the Pair Trawl suffered current net profits loss most by ratio of minus 9.4% and other fisheries such as Coastal Stow Nets, Coastal Angling, Danish Sein also suffered ratio of 7% and more in the loss of current net profits. With the deteriorating fishing performance, coupled with the increasing international crude oil prices, it is urgently required that the authorities concerned deliberate in depth on such schemes as follows in efforts to secure stable fishing production. First, provision of large-scale storage facilities for oil is needed to timely adapt to the fluctuations in international crude oil prices. Secondly, in line with the stabilization of tax-free oil prices, duty levied on oils for fishing and tax collected from the refineries need to be tax-exempt. Thirdly, the beneficiaries from the provision of tax-free oil should be broadened, not limited to special fishing operation only. Fourth, investment in stabilization of the oil prices should be encouraged, possibly through funding from the formation of fisheries development funds underway.

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.71-80
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• 2016

PERT(Project Evaluation and Review Technique) is typical method in order to probabilistically establish the schedule plan for large scale complex project or mega project. PERT technique is impossible to estimate relationship of each activity probabilistically when there are overlapping relationships because it is limited to Finish-to-Start(FS) relationship. In order to overcome this kind of limitation of PERT technique, PLET(Probabilistic Linkage Evaluation Technique) has been suggested to probabilistically estimate project duration for various overlapping relationships for each activity. However, estimating project duration by PLET technique only considers uncertainty of relationship between activities and not activity time, thus it is not the perfect duration estimating method. The main objective of this research is to propose the integration model of PERT and PLET and verify its probabilistic validity. By verifying application of time calculation method of integration model in practical case, this research will suggest probabilistic project duration estimating method in schedule plan of high-risk construction industry.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.397-409
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• 2014

The appearance of faults during tunnel construction is often difficult to predict in terms of strike, dip, scale, and strength, even though this information is essential in determining the strength of the surrounding rock mass. However, the strength and rock mass classification of fault zones are generally determined empirically on the construction site. In this study, 109 specimens were collected from fault of nine area throughout Korea, and direct shear tests were conducted and the particle distribution was analyzed to better characterize the fault zones. Six multiple regression models were established, using 97 of the specimens, to analyze the correlation between the shear strengths and weight rations of these fault materials. A verification of the six models, using the remaining 12 specimens, shows that in all of the models the coefficient of determination yielded $R^2{\geq}0.60$, with two models yielding $R^2{\geq}0.69$. These results provide useful information for determining the shear strength of fault materials in future studies.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.45-51
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• 2001

In order to investigate the optimal design weight of sinkers for preventing cage net from deforming in current, the model experiment on 2 types of square cage nets with different S sub(n)/S, the ratio of total area of netting projected to the perpendicular to the water flow S sub(n) to wall area of netting S, and 4 kinds of sinkers was carried out in circulation water channel. The model cage nets were made in 1/10 scale and the total weight in water of 4 sinkers attached to each corner of their bottom frames was 18, 54, 90, and 126g, respectively equivalent to 0.1, 0.3, 0.5, and 0.7 kg per unit area of prototype net. The results obtained can be summarizes as follows; Due to the deformation of each net where it was lifted towards the surface in severe conditions, its volume was reduced. This depended highly on the weight of sinkers placed in the bottom corner of cage nets, even if the variation of S sub(n)/S had a little effect on their deformation in current less than 0.4 m/s. In addition, it was observed that the total weight of sinkers for preventing the net from deforming to the extent of less than 50% inside its initial volume was 31 to 245 kg in the range of 0.3 to 0.6 m/s and the adequate design weight of sinker was approximately 0.5 kg per its unit area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.15 no.1
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• pp.5-16
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• 1979

At the holding of live anchovies which will be used as bait for the skipjack fishing, it is necessary to transrer the holding creel to the holding ground from the long distanted fishing ground. Usually, the creel made with net webbing and shaped like pound, was towed with a tow rope fastened to the front fringe or it, when two serious problems were found. The one was that the leading flap or the webbing of creel was drifted backward by the drag and caused to decrease the volume of the creel and made anchovies mortal. The other was that much time were spent to tow creels for long distance with slow speed, whereas to tow fast made anchovies worn out and caused them mortal. To prevent these defect, the authors carried out a model experiment in a circular flowing tank with a 1/15 scale model creel by four different arrangement of towing, and found out two suitable method, then these two methods were experimented in the sea with full rigged creel, and found the most suitable method out. To decrease the interior current speed of the creel even if it was towed fast, the apron which made by the same webbing of the creel body was enclosed the leading flap of creel, when the interior current speed showed the 35 to 40 percent of towing speed, whereas it showed 50 to 55 percent without apron.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.99-112
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• 1988

Questionnaires and blood pressure measurements were administered to 279 medical school undergraduates in 1987 to investigate the relationship between psychosocial factors and blood pressure as well as reliability and validity of the Framingham Type A Behavior Scale(FTA). The reliability coefficients of SCL-90-R and nh measured by Spearman-Brown haves split test were $0.57{\sim}0.91$. The factors of FTA extracted by principal component analysis were hard-driving competitiveness factor and impatience factor(2-factor solution) . The total score of nh was positively correlated with relative weight and place raised but the correlations were insignificant, and had significantly positive but weak correlations with depression, anxiety, hostility, paranoid, and psychoticism subscales of SCL-90-R. In the univariate analysis of blood pressures, relative weight and family history were significant in systolic pressure in males and economic status was significant in blood pressures in both sexes. For diastolic pressure, relative weight and frequency of alcohol intake were significant in males and relative weight was in females. After controlling relative weight, the frequency of alcohol intake for diastolic pressure and economic status for systolic pressure were significant in males. The important variables selected by stepwise regression analysis were relative weight and economic status for systolic pressure of males and relative weight and the frequency of alcohol intake for diastolic pressure. At the level of alpha 0.1, depression subscale was added to the model, changing coefficient of determination 0.206 to 0.217. In females, economic status and relative weight were selected for systolic pressure and for diastolic pressure body mass index alone, but the model of blood pressure for females was considered to be unstable due to small sample size(56). FTA was unrelated to the blood pressures in both sexes.