• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1229-1237
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• 2011

The volume ray-casting method is one of the direct volume rendering methods that produces high-quality images as well as manipulates semi-transparent object. Although the volume ray-casting method produces high-quality image by sampling in the region of interest, its rendering speed is slow since the color acquisition process is complicated for repetitive memory reference and accumulation of sample values. Recently, the GPU-based acceleration techniques are introduced. However, they require pre-processing or additional memory. In this paper, we propose efficient point-primitive based method to overcome complicated computation of GPU ray-casting. It presents semi-transparent objects, however it does not require preprocessing and additional memory. Our method is fast since it generates point-primitives from volume dataset during sampling process and it projects the primitives onto the image plane. Also, our method can easily cope with OTF change because we can add or delete point-primitive in real-time.

• Journal for History of Mathematics
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• v.24 no.1
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• pp.63-73
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• 2011

This paper analyses conceptual change from Euclid's dictionary definition to Hilbert's mathematical definition about primitive terms in Geometry. Realism, conceptualism, nominalism about mathematical objects are related to this conceptual change.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.164.3-164
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• 2001

In this paper, we present a method for obtaining the actual modeling data through reconstructing a 3D data from an image and a method of estimating the geometrical information and the camera location of architectural objects from a photograph containing a virtual environment are introduced. Our approach combines both geometry-based and image-based modeling techniques. The modeling system is effective and robust because it exploits constrains that are characteristic of architectural scenes. Our approach can recover models for use in either geometry-based rendering systems. We present results that demonstrate out approach´s ability to create realistic renderings of architectural scenes from viewpoints far from the original photographs.

• ETRI Journal
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• v.37 no.3
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• pp.617-625
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• 2015

In this paper, a steering control system for the path tracking of autonomous vehicles is described. The steering control system consists of a path tracker and primitive driver. The path tracker generates the desired steering angle by using the look-ahead distance, vehicle heading, and a lateral offset. A method for applying an autonomous vehicle to path tracking is an advanced pure pursuit method that can reduce cutting corners, which is a weakness of the pure pursuit method. The steering controller controls the steering actuator to follow the desired steering angle. A servo motor is installed to control the steering handle, and it can transmit the steering force using a belt and pulley. We designed a steering controller that is applied to a proportional integral differential controller. However, because of a dead band, the path tracking performance and stability of autonomous vehicles are reduced. To overcome the dead band, a dead band compensator was developed. As a result of the compensator, the path tracking performance and stability are improved.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.363-369
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• 2008

In this paper, we have proposed 3D shape reconstruction using superquadrics and single z-buffer Constructive Solid Geometry (CSG) rendering algorithm. Superquadrics can obtain various 3D model using 11 parameters and both superquadrics and deformed-superquadrics play a role of primitives which are consisted of CSG tree. In addition, we defined some effective equations using z-buffer algorithm and stencil buffer for synthesizing 3D model. Using this proposed algorithm, we need not to consider the coordinate of each 3D model because we simply compare the depth value of 3D model.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.804-818
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• 2004

As spatial data resources become more abundant, the potential for conflict among them increases. Those conflicts can exist between two or many spatial datasets covering the same area and categories. Therefore, it becomes increasingly important to be able to effectively relate these spatial data sources with others then create new spatial datasets with matching geometry and topology. One extensive spatial dataset is US Census Bureau's TIGER file, which includes census tracts, block groups, and blocks. At present, however, census maps often carry information that conflicts with municipally-maintained detailed spatial information. Therefore, in order to fully utilize census maps and their valuable demographic and economic information, the locational information of the census maps must be reconciled with the more accurate municipally-maintained reference maps and imagery. This paper formulates a conceptual framework and two map models of map conflation to make geometrically and topologically consistent source maps according to the reference maps. The first model is based on the cell model of map in which a map is a cell complex consisting of 0-cells, 1-cells, and 2-cells. The second map model is based on a different set of primitive objects that remain homeomorphic even after map generalization. A new hierarchical based map conflation is also presented to be incorporated with physical, logical, and mathematical boundary and to reduce the complexity and computational load. Map conflation principles with iteration are formulated and census maps are used as a conflation example. They consist of attribute embedding, find meaning node, cartographic 0-cell match, cartographic 1-cell match, and map transformation.

• Korean Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.20-32
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• 1996

The boundary evaluation technique for Boolean operation on non-manifold models which is regarded as the most popular and powerful method to create and modify 3-D CAD models has been developed. This technique adopted the concept of Merge and Selection in which the CSG tree for Boolean operation can be edited quickly and easily. In this method, the merged set which contains complete information about primitive models involved is created by merging primitives one by one, then the alive entities are selected following the given CSG tree. This technique can support the hybrid representation of B-rep(Boundary Representation) and CSG(Constructive Solid Geometry) tree in a unified non-manifold model data structure, and expected to be used as a basic method for many modeling problems such as data representation of form features, and the interference between them, and data representation of conceptual models in design process, etc.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.04a
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• pp.43-50
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• 2000

The flow field of a 1 Ton/Day entrained-flow gasifier constructed in KIER was numerical simulate in this paper. The standard $k-{\varepsilon}$ turbulence model and simple procedure was used with the Primitive-Variable methods during computation. In order to find the influence factors of the flow field which may have great effects on coal gasification process inside gasifier, difference geometry parameters at various operating conditions were studied by simulation methods. The calculation results show that the basic shape of the flow field is still parabolic even the oxygen gas is injected from the off-axis position. There exist an obvious external recirculation zone with a length less than 1.0m and a small internal recirculation region nears the inlet part. The flow field inside the new gasifier is nearly similar as that of the old 0.5T/D gasifier at same position if the design of burner remains unchanged.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.1
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• pp.1-9
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• 1993

Various geometric modeling techniques for a hull have been developed with wide application of computer to the ship design. Up to now, they are used for the representation of the sculptured surface with the piecewise polynominal curves or surfaces for a conventional hull. In this paper, a convenient and accurate modeling technique that is instancing and blending of the geometry primitives is introduced for a non-conventional hull such as SWATH, trimaran, caisson etc. Geometric characteristics, hydrostatic particulars and stability of the definded hull are calculated.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.359-366
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• 2019

Indoor spatial data has great importance as the demand for representing the complex urban environment in the context of providing LBS (Location-based Services) is increasing. IndoorGML (Indoor Geographic Markup Language) has been established as the data standard for spatial data in providing indoor navigation, but its definitions and relationships must be expanded to increase its applications and to successfully delivering information to users. In this study, we propose an approach to integrate IndoorGML with Indoor POI (Points of Interest) data by extending the IndoorGML notion of space and topological relationships. We consider two cases of representing Indoor POI, by 3D geometry and by point primitive representation. Using the concepts of the NRS (node-relation structure) and multi-layered space representation of IndoorGML, we define layers to separate features that represent the spaces and the Indoor POI into separate, but related layers. The proposed methodology was implemented with real datasets to evaluate its effectiveness for performing indoor spatial analysis.