• Advanced Composite Materials
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• v.17 no.3
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• pp.247-258
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• 2008

This paper is concerned with the long-term performance of geo-textile (GT) composites in terms of creep deformation and frictional properties. Composites of PVA GT and HDPE GM were made to investigate the advanced properties of long-term performance related to waste landfill applications. The same experiments were also performed for typical polypropylene and polyester GT and compared to PVA GT/HDPE GM composites. We also develop high performance GT composites with GM by using PVA GT, which is capable of improving the frictional properties and thus enhances long-term performance of GT composites. Experimental study reveals that the friction coefficient of GT composites is relatively large compared with those of polyester and polypropylene non-woven GT as long as the friction media has similar size to the particles of domestic standard earth. In addition, the geo-composites bonded with geo-grid by a chemical process were investigated experimentally in terms of strain evaluation and creep response values. Geo-grid plays an important role as a reinforcing material. Three kinds of geo-grid were prepared as strong yarn polyester and they were woven type, non-woven type, and wrap knitted type. The sample geo-grids were then coated with PVC. The rib tensile strength tests were conducted to evaluate geo-grid products in terms of tensile strength with regard to single rib. The test was performed according to GRI-GGI. It was concluded again from the experiments that the tensile and creep strains of the geo-grid showed such stable values that the geo-grid prepared in this study could protect geo-textile partially in practical structures.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.143-149
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• 2008

전 지구적 기온상승으로 인하여 해수면 상승 및 자연생태계가 파괴되고 있다. 이에 Geo 관련 연구자들은 지구 온난화, 이산화탄소 배출량, 미세먼지 확산 등의 방대한 지구환경정보를 공유 및 교환하고 활발한 지식 교류를 하기 위한 포털 환경이 요구되고 있다. 국외 여러 환경단체들은 이러한 포털 환경구축을 통해 지구 환경정보를 연구하고 있다. 한국에서도 지구온난화 영향분석, 미세먼지 확산분석, 이산화탄소 배출량 분석 지상 식생변화 모니터링 등의 분야에서 위성 관측 영상 및 지구환경자료를 이용한 서비스가 더욱 절실하다. e-Science 환경 구축의 대표 응용 분야 중의 하나로 발전, 확산시킬 필요성 때문에 정확하고 방대한 지식정보의 신속한 처리 및 서비스를 할 수 있는 GeoGrid 기반 기술 개발 방법과 환경 구축 방법에 대해 연구하였다.

• Spatial Information Research
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• v.23 no.6
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• pp.43-55
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• 2015

Currently, each organization has developed its gridded data in the form of respective grid system for its own purpose. Interoperability among the organization had been limited and resulted in inconvenient data access and application across domains. In this study, we investigated potential standards for National grid system and their strength and weakness. We also reviewed existing gridding schemes and had a survey of demand about grid system to those who have used or would plan to use gridded data in academic and business sectors. As the result of survey of demand, we suggested national grid system for national grid data integration management system which has the mutual compatibility and also proposed sharing scheme of the grid type for users who need to grid data.

• Journal of the Korean GEO-environmental Society
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• v.16 no.3
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• pp.49-55
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• 2015

The rainfall pattern, rainfall intensity as well as topographical conditions used for the analysis of debris flow affect, in general, the magnitude of debris flow and flow velocity, when debris flow occurs. The consideration of topographical conditions implies that the topography is equally divided into grids and the slope of inside the grid is computed as an average, leading to, in turn, obtain the closer results to the reality as the grid is smaller in the case of the severely bended topography. Although the size of grid should be as small as possible so as for more accurate analysis of debris flow, the analysis of debris flow has been so far conducted by using sparsely divided grids due to the limitation of analysis algorithm, computational ability and running time. So, it is necessary to suggest an appropriate grid size for the practical approaches. Therefore, this study presents the evaluation of the effect of the size of a grid on the debris flow besides the factors which referred to the previous studies such as accumulated rainfall, rainfall intensity and rainfall duration time. From this, it enables to suggest a rational and practical grid size for topography to be divided.

• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.573-582
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• 2009

• 기술발표회
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• s.2006
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• pp.162-171
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• 2006

Segmental Grid Retaining Wall is one of the segmental grid retaining walls using headers and stretchers to establish the framework of the wall In this method, grids formed by the intersection of headers and stretchers are generally filled with the gravel to maintain the weight of the wall Therefore, the construction can be carried out with higher speed and much economically when compared with the concrete retaining wall Furthermore, it has high drain capacity, and environmentally friendly aspects also have been pointed out because the possibility of the planting at the front of the wall However, in the segmental grid retaining wall method, the relative movement between the individual headers and stretchers was generally recognized, and stress redistribution in the gravel filling was also observed when subjected to the external loading and self-weight of filling Therefore, it has been thought that the distribution of the earth pressure in the segmental grid retaining wall system differ from that of the concrete retaining wall In this study, the surcharge tests using the scaled model segmental grid retaining wall was carried out to observe the distribution of the earth pressure in the segmental grid retaining wall The earth pressure was measured in the six specified height of wall, and the distribution of the pressure was analyzed. Furthermore, the earth pressure by computation or by the test using the concrete retaining wall was also considered to make comparison

• Spatial Information Research
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• v.23 no.1
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• pp.19-31
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• 2015

Due to the global warming and unstable abnormal climate changes, water resources differences between regions and water shortage are occurring. Therefore, the water resources management is becoming more important for the stable securement of future water supply and demand. Researches on Smart Water Grid (SWG), which is considered as a new method, that can stably secure and maintain the water resources, are actively being conducted but it is still in infancy. Thus, this study aimed to design SWG simulator based on GIS in order to provide integrated water information in web environment. The user's requirements were analyzed for system development and important functions such as SWG current situation checking, future prediction, filtration plant situation checking functions were designed and data expression techniques using GIS and HTML5 were applied to enhance the understanding of the users. Also, when the emergency situations occurred, the solving process of the situations are reproduced to check the solution process using scenario reproduction functions. Use-case, class, sequence diagram, which are a design for real system development and defines the system usage contents of users, were written, and the story board was written to check the final development contents. This study designed a SWG simulator in order to support the water maintenance reacting to climate changes. The development of system is expected to help securing information to deal with emergency situations such as water shortage and help the decision maker to make decision through reproduction of scenario. The major functions were designed for the convenience of water resource manager and producer but new contents for consumers must be developed to enable duplex information transmission.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.375-386
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• 2015

The study aims at a selective effect of the Grid and Window net in the shrimp beam trawl. The experimental trawling of the Proto type, Grid type and Grid and Window net type was performed in a sea area of Geo-je and Tong-yeong from Mar, 2006 to Apr, 2010. The obtained results are as follows; Catch per unit area (Number) of the Proto type net and Grid type net were $0.18/m^2$, $0.23/m^2$, respectively. The Grid type demonstrated 2.4% lower bycatch rate than the proto type (6.6% vs 4.2%, respectively). In addition, in terms of total weight, the bycatch rate of Grid type was 7.6% lower than the proto type (50.2% vs 42.6%, respectively). In the comparison of shrimp catch, the Proto type demonstrated better haul outcome ($0.02case/m^2$) than the Grid & Window type ($0.02case/m^2$). The Grid & Window net type demonstrated 16.4% lower bycatch rate than the Proto type (32.2% vs 48.6%, respectively). In addition, in terms of total weight, the bycatch rate of Grid & Window net type was 8.3% lower than the Proto type (85.9% vs 94.2% respectively).

• Korean Journal of Remote Sensing
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• v.19 no.5
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• pp.363-370
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• 2003

This paper describes a rectification procedure that relies on a polynomial model derived from the imaging geometry without loss of accuracy. By using polynomial model, one can effectively eliminate the iterative process to find an image pixel corresponding to each output grid point. With the imaging geometry and ephemeris data, a geo-location polynomial can be constructed from grid points that are produced by solving three equations simultaneously. And, in order to correct the local distortions induced by the geometry and terrain height, a distortion model has been incorporated in the procedure, which is a function of incidence angle and height at each pixel position. With this function, it is straightforward to calculate the pixel displacement due to distortions and then pixels are assigned to the output grid by re-sampling the displaced pixels. Most of the necessary information for the construction of polynomial model is available in the leader file and some can be derived from others. For validation, sample images of ERS-l PRI and Radarsat-l SGF have been processed by the proposed method and evaluated against ground truth acquired from 1:25,000 topography maps.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.171-180
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• 2016

Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.