• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.39-47
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• 2013

Recently, there have been various domestic construction activities related to the reclamation of the dredged soils to expand the land use. However, the reclaimed grounds made of the dredged soils cause various problems due to highly compressible and low shear strength nature. Particularly, this nature induces huge problems in case of the harbor facilities and road construction on the reclaimed sites. Furthermore, in the reclamation activities, the marine dredged soils are often used instead of the well sorted sand, which induces problems of compressibilities. Therefore, in this study, the mechanical characteristics of artificial soil mixture of kaolinite representing the marine dredged soils and the pond ash. A large consolidometer is designed and manufactured to produce the artificial soil mixture. To represent various mixing ratio between the fly ash and bottom ash in the pond ash, six samples with the same stress history are made with different mixing ratio among kaolinite, bottom ash and fly ash. Isotropically consolidated and undrained compression tests are performed to investigate the shear characteristics of soil mixtures. Based on the experimental results, as the components of mixed ash increase, the friction angle increase and the cohesion values decrease. Also, the porepressure parameters at failure, Af increase with the mixing components of the pond ash. The portion of bottom ash has more impact on the shear behavior than that of fly ash.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.185-190
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• 2015

Greenhouse gas (GHG) emission from agricultural lands is recognized as one of important factors of global warming. The objective of this short communication was to evaluate the applicability of different soil GHG emission prediction models on agricultural systems in Korea. Four models, namely, DNDC, DAYCENT, EXPERT-N and COUP, were selected and the basic structure (e.g., components and sub-model), input variables, and output variables were compared. In particular, the availability and compilation of essential input variables were assessed. Major input variables needed for operating these predictive models were found to be available through database systems established by national organizations such as the Korea Meteorological Administration, the Korean Soil Information System, and the Rural Development Administration. However, in order to apply these models in Korea, it was necessary to calibrate and validate each of the models for the domestic landscape settings and climate conditions. In addition, field data of long-term monitoring of GHG emission from agricultural lands are limited and therefore should be measured.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6360-6367
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• 2015

The location selection of the element that should guarantee easy visual perception, like the landmark, is the a topic that appears much in the design process. Recently, a graph analysis technique using computers has been applied in order to evaluate the visibility of the visual element, but the analytic frame is flat and the setting of the visual pont and the matrix are fixed so there were great limitations in obtaining the results of the practical analysis. Thus, this study presented Nondirectional Multi-Dimensional Calculation (MDVC-N), an analytic methodology available for the analysis of the dynamic visual point in the 3D environment. It thus attempted to establish the analytic application using the 3D computer graphics technology and designed a script structure to set the visual point and the matrix. In addition to that, this study tried to verify the analytic methodology by applying the complex land as an example model, where buildings in various heights of terrains with a high-differences are located, verifying the same analytic methodology. It thus tried to identify the visual characteristics of each alternative location. The following results were gained from the study. 1) The visibility can be measured quantitatively trough the application of the 6-alternatives. 2) Using the 3dimensional graph, intuitive analysis was possible. 3) It attempted to improve the analytic applicability by calculating the results corrected as a variable behavior from the local integration variable of the space syntax.

• Journal of the Korean Geographical Society
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• v.41 no.3 s.114
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• pp.331-345
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• 2006

This study deals with geomorphological process of the sand dune landform including the distribution and surface environments, characteristics of sediments, origins and moving processes in lower reach and mouth delta of Duman River, Northeast Korea and China. The methodology of the study includes image analysis of Landsat TM(1992.10) and ETM(2000.9) and Spot(2005.4) for analysis of land cover, 2 times field survey for recognition of landform and acquisition of sediments raw data materials, and grain analysis and exoscopy about raw data materials. The geomorphic elements from satellite image analysis are composed of the delta, sand spit, active and stable dune, sand bar and riparian vegetated zone. Results of the grain analysis indicate the sediments originated from marine coastal zone than riverine one. This means that present sand dune not so much reflect present climatic and geomorphic environments. Result of the exoscopy analysis show that ratio of quartz, which is comparatively resistant to environment, is highest as $65{\sim}83%$ out of sediments. But the surface of the $30{\sim}40%$ of mineral grains was coated by yellow-colored stained materials, due to chemical weathering. Some grains show rough skin, looking as acicular, network structure and etching pits, affected by physical and chemical weathering.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.47-56
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• 2013

The present study proposed a methodology to analyze the networking efficiency of arterial road networks. The methodology was motivated to design three-dimensional networks and to analyze the networking ability quantitatively, which is a novel approach compared to existing methods depending on the two-dimensional network definition and the qualitative analysis for improving arterial road networks. The method considered the interdependence between high-level freeways and low-level highways, the ITS-based information for traffic and road conditions, and the physical networking. These three factors were quantified by a networking index (NI), and the networking efficiency was measured by a networking rate (NR). The present study proved that the networking efficiency (NR) was influenced by travel information sharing (i.e., ITS) and physical factors. This supports the fact that the integrated improvements of physical and ITS factors are necessary for an arterial road. The proposed method was applied for an actual arterial road network. It was found that the nation-wide NR was higher than that for the metropolitan area, which might be due to the difficulty in switching between high- and low-level networks and the lack of ITS functions in the metropolitan area.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.183-196
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• 2017

In this study, policy evaluation scheme was established to encourage the efficient implementation of EcoMobility which has been expanding gradually all around the world. A total of eight evaluation goals and 22 evaluation items are reviewed and suggested based on the three major evaluation categories of "Basic elements for EcoMobility", "Land use and transport system for EcoMobility", and "Implications and impact of EcoMobility". The results of this study are as follows: the result of AHP analysis which reflects only the hierarchical structure shows a high priority in "Elements for EcoMobility promotion", "Eco-fiendly transport infrastructure", and "Safety in transport". While in result of ANP which considered the elements' dependencies, "Eco-fiendly transport Services", "Welfare in transport", and "Environment by transport" have high weights and importances. In conclusion, this study would be useful to make reasonable judgment based on the analysis results of the two techniques in order to ensure reliability in evaluation of EcoMobility policy. Furthermore we have confirmed appropriate evaluation technique between AHP and ANP which is better to reflect the features of EcoMobility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.737-744
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• 2016

Seoul Metropolitan Area has been changed by fierce internal migration during the last several decades. To determine the regional structure, we analyzed the in-and-out migration pattern and main factors affecting the intense of mobility. The migration within metropolitan city and province shows that in Seoul, Songpa and Dobong Gu gained a large population, in Incheon, Namdong Gu experienced a huge population influx, and in Gyeonggi Province, Hwasung, Yongin and Paju city gained a great population. In Seongnam, Suwon city lost a lot of population. These population gains and losses came from mainly residential redevelopment projects in the metropolitan city and new land development projects in Gyeonggi Province. The main factors affecting the intense of mobility diverse from city characters. In central type cities, house price gets the more population influx. In job-housing balanced cities, total income growth rate, housing supply rate and roads cause in-migration. In bed-town type cities, the increase of housing supply rate and parks increase the population. In suburban type cities, business density, housing supply rate, housing, subway station number and educational facilities increase population from outside the city. So, we have to prepare more detailed urban and housing policy responses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.8-15
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• 2020

In the present paper, as a way of reducing heavyweight impact sounds, in particular, among floor impact sounds which have come to the forefront as a social issue recently, a floor joist slab is proposed that is expected to bring an effect of reducing heavyweight impact sounds through a shift in the natural frequency by installing a floor joist on a flat-type slab to increase the rigidity of the floor slab, differently from the existing method that increases the thickness of floor slab, and the heavyweight impact sound characteristics depending on the floor joist height and interval are interpretively analyzed. As a result of the analysis, though a trend is shown where the sound pressure level decreases as the slab thickness of floor joist increases, and as no difference is shown when thickness is above a certain value, it is thought that there is a threshold for the effect of an increase in floor thickness on blockage of heavyweight impact sounds. Also, as an increase in floor rigidity resulting from an increase in the floor joist height and a decrease in the interval does not lead to a consistent increase in the performance of blocking heavyweight impact sounds, it is thought that a different floor joist height and interval should be applied to each type of house to expect optimum performance of blocking heavyweight impact sounds, and an increase of 100mm in the floor joist height or a decrease of about 100mm in the interval is expected to bring an effect of reducing heavyweight impact sounds by about 1dB to 2dB.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.729-742
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• 2019

Natural disasters such as floods has been increased in many parts of the world, also Korea is no exception. The biggest part of natural damage in South Korea was caused by the flooding during the rainy season in every summer. The existing flood vulnerability analysis cannot explain the reality because of the repeated changes in topography. Therefore, it is necessary to calculate a new flood vulnerability index in accordance with the changed terrain and socio-economic environment. The priority of the investment for the flood prevention and mitigation has to be determined using the new flood vulnerability index. Total 25 urban districts in Seoul were selected as the study area. Flood vulnerability factors were developed using Pressure-State-Response (PSR) structures. The Pressure Index (PI) includes nine factors such as population density and number of vehicles, and so on. Four factors such as damage of public facilities, etc. for the Status Index (SI) were selected. Finally, seven factors for Response Index (RI) were selected such as the number of evacuation facilities and financial independence, etc. The weights of factors were calculated using AHP method and Fuzzy AHP to implement the uncertainties in the decision making process. As a result, PI and RI were changed, but the ranks in PI and RI were not be changed significantly. However, SI were changed significanlty in terms of the weight method. Flood vulnerability index using Fuzzy AHP shows less vulnerability index in Southern part of Han river. This would be the reason that cost of flood mitigation, number of government workers and Financial self-reliance are high.

• Geophysics and Geophysical Exploration
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• v.6 no.4
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• pp.171-179
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• 2003

In land and marine seismic survey, we generally set receivers with equal interval suppose that sampling interval Is too narrow. But the cost of seismic data acquisition and that of data processing are much higher, therefore we should design proper receiver interval. Spatial aliasing can be occurred on seismic data when sampling interval is too coarse. If we Process spatial aliasing data, we can not obtain a good imaging result. Trace interpolation is used to improve the quality of multichannel seismic data processing. In this study, we applied the Spitz algorithm which is widely used in seismic data processing. This algorithm works well regardless of dip information of the complex underground structure. Using prediction filter and original traces with linear event we interpolated in f-x domain. We confirm our algorithm by examining for some synthetic data and marine data. After interpolation, we could find that receiver intervals get more narrow and the number of receiver is increased. We also could see that continuity of traces is more linear than before Applying this interpolation algorithm on seismic data with spatial aliasing, we may obtain a better migration imaging.