• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.946-951
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• 2004

ITIS is applied to the several tunnel construction sites in Korea. Tunnel construction properties which are acquired from these sites are transferred to information management server(SQL 2000 server)by client application program in real time. Access permission to DB server depends on the user's roles. Some functions which cannot be embodied in SQL Server are serviced through XML and GMS server is used for spatial data based on GIS part. This system is supposed to give engineers the advantages which are not only easy handling of the program and computerized documentation on every information during construction but also analyzing the acquired data in order to predict the structure of ground and rock mass to be excavated later and show the guideline of construction. Neung-Dong tunnel and Mu-Gua express way tunnel are now under construction and with this system they have 3D visualized map of the geology and tunnel geometry and accumulate database of construction information such as tunnel face mapping results, special notes and pictures of construction and 3D monitoring data, all matters on the stability of rock bolts and shotcrete, and so on. Ground settlement prediction program included in ITIS, based on the artificial neural network(ANN) and supported by GIS technology is applying to the subway tunnel. This prediction tool can make it possible to visualize the ground settlement according to the excavation procedures by contouring the calculated result on 3D GIS map and to assess the damage of buildings in the vicinity of construction site caused by ground settlement.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.4 s.38
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• pp.61-70
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• 2006

This paper presents photogrammetric processing to generate digital elevation models using SPOT-5 HRG stereo images and deals with the accuracy potential of HRG (High Resolution Geometry) supermode imagery for DEM generation. After bundle adjustment was preformed for sensor modelling, digital surface models were generated through the procedures of Epipolar image resampling and image matching. The DEM extracted from HRG imagery was compared along several test sections with the the refernce DEM which was obtained from the digital topographic maps of a scale of 1 to 5000. The ratio of the zone with DEM errors less than 5m to the whole zone was 53.8%, and about 2.5m RMSE was showed when assuming that the zones larger than 5m were affected by clouds, water bodies and buildings and excluding those zones from accuracy evaluation. In addition, the three-dimensional bird's eye view model and 3D building model were producted based on the DSM which was extracted from SPOT-5 HRG data.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1999.12a
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• pp.47-51
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• 1999

Geo-features play a key role in object-oriented or feature-based geo-processing system. So the strategy for how-to-model and how-to-manage the geo-features builds the main architecture of the entire system and also supports the efficiency and functionality of the system. Unlike the conventional 2D geo-processing system, geo-features in 3D GIS have lots to be considered to model regarding the efficient manipulation and analysis and visualization. When the system is running on the Web, it should also be considered that how to leverage the level of detail and the level of automation of modeling in addition to the support for client side data interoperability. We built a set of 3D geo-features, and each geo-feature contains a set of aspatial data and 3D geo-primitives. The 3D geo-primitives contain the fundamental modeling data such as the height of building and the burial depth of gas pipeline. We separated the additional modeling data on the geometry and appearance of the model from the fundamental modeling data to make the table in database more concise and to allow the users more freedom to represent the geo-object. To get the users to build and exchange their own data, we devised a fie format called VGFF 2.0 which stands for Virtual GIS File Format. It is to describe the three dimensional geo-information in XML(extensible Markup Language). The DTD(Document Type Definition) of VGFF 2.0 is parsed using the DOM(Document Object Model). We also developed the authoring tools for users can make their own 3D geo-features and model and save the data to VGFF 2.0 format. We are now expecting the VGFF 2.0 evolve to the 3D version of SVG(Scalable Vector Graphics) especially for 3D GIS on the Web.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.635-641
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• 2016

Because of prohibitive data storage requirements in large-scale simulations, the memory problem is an obstacle for Monte Carlo (MC) codes in accomplishing pin-wise three-dimensional (3D) full-core calculations, particularly for whole-core depletion analyses. Various kinds of data are evaluated and quantificational total memory requirements are analyzed based on the Reactor Monte Carlo (RMC) code, showing that tally data, material data, and isotope densities in depletion are three major parts of memory storage. The domain decomposition method is investigated as a means of saving memory, by dividing spatial geometry into domains that are simulated separately by parallel processors. For the validity of particle tracking during transport simulations, particles need to be communicated between domains. In consideration of efficiency, an asynchronous particle communication algorithm is designed and implemented. Furthermore, we couple the domain decomposition method with MC burnup process, under a strategy of utilizing consistent domain partition in both transport and depletion modules. A numerical test of 3D full-core burnup calculations is carried out, indicating that the RMC code, with the domain decomposition method, is capable of pin-wise full-core burnup calculations with millions of depletion regions.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.45-51
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• 2013

Today, people who live in sea of information are strongly appearing desire about quicker and more accurate information. For a long time people wanted to know information about place that I am and where I must go out, and there are various methods to have a keen desire for position information. Equipment that is using most among the method is digital camera. In this study, the accuracy of external orientation, GCP and check point depending on array of GCP and regional feature are analyzed after AT(aerial triangulation) with UltraCamX in three selected study area with specific feature. As analysis result, we could get to know that area with a mountainous district rapidly decreased accuracy of external orientation according as number of GCP decreases, and area with high buildings became low in vertical accuracy of checkpoint. This study has performed the analysis of regional factors in aerial triangulation accuracy.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.287-294
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• 2019

This study investigated longitudinal changes in riverbed materials properties and temporal alteration of river channel geomorphology in the Geum River basin, where two multipurpose dams(Yongdam Dam and Daecheong Dam) were built in upstream area. We carried out grain size distribution analyses and measured soil organic matter contents of riverbed materials taken at the upper and lower sites of the two large dams. We also estimated the channel width, bar area and vegetation encroachment using the oldest map and aerial photographs taken before and after the construction of the dams. The results can contribute to increasing understandings of dam induced habitat alteration in river ecosystem.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.41-48
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• 2014

Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1457-1467
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• 2015

Depending on the type of Tx-Rx pairs, VHF Data Exchange System (VDES) for maritime communication is expected to employ the different frequency channels. Load imbalance between the different channels turns out to be a critical problem for the multi-hop communication using Ad-hoc Self-Organizing TDMA (ASO-TDMA) MAC protocol, which has been proposed to provide the connectivity between land station and remote ship stations. In order to handle the inter-channel load imbalance problem, we consider a model of the stochastic geomety in this paper. After analyzing the spatial reuse efficiency in each hop region by the given model, we show that the resource utility can be maximized by balancing the inter-channel traffic load with optimal resource allocation in each hop region.

• Geophysics and Geophysical Exploration
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• v.7 no.1
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• pp.14-18
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• 2004

High levels of ambient noise and safety factors often limit the use of 'active-source' seismic methods for geotechnical investigations in urban environments. As an alternative, shear-wave velocity-depth profiles can be obtained by treating the background microtremor wave field as a stochastic process, rather than adopting the traditional approach of calculating velocity based on ray path geometry from a known source. A recent field test in Melbourne demonstrates the ability of the microtremor method, using only Rayleigh waves, to resolve a velocity inversion resulting from the presence of a hard, 12 m thick basalt flow overlying 25 m of softer alluvial sediments and weathered mudstone. Normally the presence of the weaker underlying sediments would lead to an ambiguous or incorrect interpretation with conventional seismic refraction methods. However, this layer of sediments is resolved by the microtremor method, and its inclusion is required in one-dimensional layered-earth modelling in order to reproduce the Rayleigh-wave coherency spectra computed from observed seismic noise records. Nearby borehole data provided both a guide for interpretation and a confirmation of the usefulness of the passive Rayleigh-wave microtremor method. Sensitivity analyses of resolvable modelling parameters demonstrate that estimates of shear velocities and layer thicknesses are accurate to within approximately $10\%\;to\;20\%$ using the spatial autocorrelation (SPAC) technique. Improved accuracy can be obtained by constraining shear velocities and/or layer thicknesses using independent site knowledge. Although there exists potential for ambiguity due to velocity-thickness equivalence, the microtremor method has significant potential as a site investigation tool in situations where the use of traditional seismic methods is limited.

• Journal of Cadastre & Land InformatiX
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• v.45 no.1
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• pp.137-150
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• 2015

The methodology on digital cadastre(World Geodetic System Conversion) needs to be specified because the primary target site is discussed for large national estate such as road, river etc. on nationwide. Comprehensively reviews on similar cases and literature reviews to make a methodology for digital cadastre on large national estate, cadastral map revision is required before converting to World Geodetic System. The revisions are on subdivision survey or the other surveys to the necessary area through inspection of geometry and attributes. And the researcher pointed out the need of registration conversion and union of parcel to remove small parcel or to remove the inconsistency of land use type. Basically a systematic maintenance of cadastral map is necessary because the World Geodetic System Conversion unresolved the poor cadastral map quality to digital cadastre on large national estate.