• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.203-206
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• 2007

In urban flood model, the features like roads, buildings, and river's banks have great effect on flow dynamics and flood propagation and it must be accounted for model set-up. Two-dimensional hydraulic models in high-density building areas are at the forefront of current research into flood inundation mechanisms, but they are however constrained by inadequate parameters of topography and friction due to insufficient and inaccurate data. This paper describes the development of urban flooding with the extraction of building areas and estimates the its influence on flood inundation extent, and present initial results of flood simulation varying grid size.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.92-104
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• 2015

In order to analyze the impacts of climate change, a time and space integrated model was developed in this study using system dynamics and GIS. The model built was used to carry out a simulation on the inundation impact on A-gu of Busan Metropolitan city resulting from the sea level rise scenario of IPCC and storm surge, which is the worst case. Through this, the flooded area and population until 2100 were predicted. Also, the result and significance of each alternative was reviewed improving the model by establishing alternative scenarios of protection, accommodation and retreat as plans of reaction to sea level rise. The combination of system dynamics and GIS has advantages of how the diverse variables change until the target year can be traced and, accordingly, not only the results but also the processes of spatial change can be examined by calculating the value of change process at each time step. The synergy of this model presumed to be a foothold for solving problems which are becoming difficult to predict due to increase in uncertainty and complexity such as the support for decision making for urban resilience to natural disasters.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.9-16
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• 2022

The relevance of the topic is determined by the existence of inconsistencies between economic and environmental aspects of innovative development of urban logistics infrastructure, as well as the conflict of public, state and private commercial interests in this issue. The purpose of the article is to determine the principles and effective tools for innovative development of urban logistics infrastructure, taking into account pandemic constraints. The influence of the environmental aspect on the dynamics of transport flows was analyzed in detail and characterized, the scheme of determining the optimal solution for the development of the city was proposed considering the compromise between economic and ecological interests of society, state and business entities. A scheme of innovative development of urban logistics infrastructure under pandemic constraints was also developed. Materials of the article are relevant for developers of city plans, managers of urban logistics infrastructure, employees of enterprises participating in transport and logistics markets, scientists, and doctoral students.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.3
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• pp.63-74
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• 1984

The system dynamics is a systematic method supplemented by the decision making Process of management to the numerical and theoretical analyses in the field of the operation research or the industrial engineering. The system dyamics seems to be one of the most useful mathematical methods for forecasting the future social system or for evaluating the alternative plans. Land-use/transportation system dynamics model is constructed from the urban activity generation model based on the economic base hyphothesis using the DYNAMO simulation language. The model was applied to Daegu city and showed the validity.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.2
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• pp.69-81
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• 2009

Using a computational fluid dynamics (CFD) model, the effects of building complexes constructed under an urban renewal plan on air flows in an urban area were investigated. For this, the geographic information system (GIS) data were used as the input data of the CFD model and four experiments were numerically simulated for different inflow directions (westerly, southerly, easterly, and northerly cases). Before constructing building complexes under the urban renewal plan, wind speed at the pedestrian level was very low around buildings because of decrease in wind speed by the drag effect of the densely distributed low-rise buildings. As the high-rise buildings were constructed and building density decreased by the urban renewal plan, wind speed at the pedestrian level increased compared to that before the urban renewal plan because the drag effect by the buildings decreases and the channeling effect satisfying the mass continuity partially appeared at the spaces among the high-rise buildings. At the upper levels, wind speed partially increased inside the high-rise buildings due to the channeling effect but it remarkably decreased across a vast extent of the downwind regions due to the generation of the recirculation zone and the drag effect of the high-rise buildings.

• Clinical and Experimental Reproductive Medicine
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• v.2 no.2
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• pp.13-26
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• 1975

Seven aspects of attitude toward marriage in Korea are examined to better understand present and future marriage patterns. Also, various facets of current marriage practice are compared with attitudes. The study comprises three groups of roughly 600 women each, selected by random sampling from a rural, an urban, and a semi-urban area. A carefully designed and pretested questionnaire was checked for reliability by a reinterview in a 15% subsample. The great majority of Korean women support traditional attitudes that one must or should marry. The small group who recommend that one should not marry are mostly the very young or the never married, whose attitudes still may change. However, there are important and probably predictive shifts in favor of more individual decision, especially among the better educated, the young, and the more urban. Traditional reasons for marriage such as "custom" and procreation are ranked first by a majority, but there is a large shift to more contemporary or liberal desire for companionship and love, also primarily among the better educated, the urban, the young, and the never married. The traditional attitude that parents should have the sole or major role in mate selection is still held by a bare majority; the educated, urban, young, and never married are more liberal. Only 6% opt for each of the two extremes: That the parent alone or the respondent alone should decide. The remainder prefer one of the two middle-of-the-road positions where parent and child together decide. The proportions of respondents who classed specified criteria as moat important for selecting a husband, arranging the criteria in order from traditional to contemporary were: Lineage, etc., 23%; personal attributes, 40%; health and education, 27%; and love, 10%. The changing attitudes are suggested by the fact that love was ranked first by only 3% of the poorly educated rural poulation versus 23% of urban college level and 31% of the urban never married. There has been a substantial rise in the ideal age of marriage over the past twelve or more years, but there also is evidence that the ideal age is at or near a ceiling. Knowledge about legal age of marriage is minimal; the implications of this for proposed legislation are discussed. Three-fifthes to four-fifths of all respondents married husbands of the same religious, residential, and economic backgrounds as themselves. Almost all of them married men of the same or higher educational level. These evidences of traditional influences in mate selection are contrasted with the low priority given some of those items in earlier questions on reasons for marriage and criterion for selecting husband. Contrary to the expressed attitudes as to who should select the husband, we find that marriages of the study sample were stated to be arranged by parents alone in 62%; and in another 23%, the parents made the decision but asked the respondent's views. Such arrangements were most frequent among the rural, the less educated, and the older respondents and less common in the urban and more educated. The implications of these and related findings are discussed.

• Wind and Structures
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• v.9 no.2
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• pp.147-158
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• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.229-238
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• 2006

In general, the Maglev vehicle is run over an elevated guideway consisting of steel or concrete structure. Since the running behavior of the vehicle is affected by the flexibility of the guideway, the consideration of the flexibility of guideway is needed for evaluating the dynamics of both the vehicle and guideway. A new method based on flexible multibody dynamics is proposed to model the Maglew vehicle. This method combines the levitation controller, vehicle, and guideway into a coupled model To verify the method, an urban transit is analyzed using the method and discussions are carried out.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.137-143
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• 2008

In the present study, a forest fire spread was simulated with a three-dimensional, fully-transient, physics-based, computer simulation program. Physics-based fire simulation is based on the governing equations of fluid dynamics, combustion and heat transfer. The focus of the present study is to perform parametric study to simulate fire spread through flat and inclined wildland with vegetative fuels like trees or grass. The fire simulation was performed in the range of the wind speeds and degrees of inclination. From the results, the effect of the various parameters of the forest fire on the fire spread behavior was analyzed for the future use of the simulation in the prediction of fire behavior in the complex terrain.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.321-329
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• 2022

High-rise buildings constructed adjacent to low-rise structures experience frequent damage caused by the associated strong wind. This study aimed to implement a standard evaluation of the wind environment and airflow characteristics around high-rise apartment blocks using wind tunnel tests (WTT) and computational fluid dynamics (CFD) simulations. The correlation coefficient between the CFD and wind tunnel results ranged between 0.6-0.8. Correlations below 0.8 were due to differences in the wake flow area range generated behind the target building according to wind direction angle and the effect of the surrounding buildings. In addition, a difference was observed between the average velocity ratio of the wake flow wind measured by the WTT and by the CFD analysis. The wind velocity values of the CFD analysis were therefore compensated, and, consequently, the correlations for most wind angles increased.