• Title/Summary/Keyword: Topological data model

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Representation of Structural Surface for Hull Modeling (선체모델링에 있어서 구조면의 정의 및 표현)

  • Kwang-Wook Kim;Won-Don Kim;Jong-Ho Nam
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.2
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    • pp.30-37
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    • 1992
  • Since a ship is a complex steel construction which consists of sculptured surfaces and inner surface members, a high technique of information modeling is indispensable to describe the form of hull surface and steel structure members consistently. A model contains both topological and geometrical information of the structural members. Therefore, the hull form should be represented by the wireframe of surface model so that the accuracy in each design stage is satisfied. The structural members like plane surfaces, stiffeners and the relations between such members are to be described systematically in data base. A collection of the data stored in database is a model to be built. The model will be used not only to generate the drawings and documents for ship design and production but also to interconnect other systems such as compartmentation, outfitting, piping, etc. Computer graphics is adopted of the visualization of model.

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A Fractal Based Approach for Multi Level Abstraction of Three Dimensional Terrain (프랙탈 기법을 이용한 3차원 지형의 다중 추상화)

  • Park, Mee-Jeong;Lee, Jeong-Jae
    • Journal of Korean Society of Rural Planning
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    • v.11 no.1 s.26
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    • pp.9-15
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    • 2005
  • Preservation of geometrical context of terrains in a digitized format is useful in handling and making modification to the data. Digitization of three-dimensional terrain still proves a great challenge due to heavy load of context required to retain details of topological and geometrical information. Methods of simplification, restoration and multi-level terrain generation are often employed to transform the original data into a compressed digital format. However, reduction of the stored data size comes at an expense of loss of details in the original data set. This article reports on an alternative scheme for simplification and restoration of terrain data. The algorithm utilizes the fact that the terrain formation and patterns can be predicted and modeled through the fractal algorithm. This method was used to generate multi-level terrain model based on NGIS digital maps with preserving geometrical context of terrains.

Restoration of Iksan Imperial Capital City Structure and Construction Model in Late Baekje from the Point of Ancient Capital City Planning (백제 후기 익산도성 조영계획모델에 대한 도성계획사적 해석)

  • Lee, Kyung-Chan
    • Journal of architectural history
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    • v.24 no.3
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    • pp.31-41
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    • 2015
  • This study aims to draw out planning principles and structure of Iksan imperial capital city in late Baekje, especially in view of the relationship among imperial capital city planning area, skeletal axis and the location of royal castle. With site survey and analysis of historical records, old maps, topographical maps, archeological excavation data, land registration map of 1915, some significant inferences were drawn out. Firstly from the point of topological conditions, the contiguous line of a stratum from Mireuk mountain(彌勒山) to Wangkung-ri castle(王宮里遺蹟) and two waterways made a topological axis of Iksan Imperial capital city. Secondly district of Iksan imperial capital city can be deduced to the inner area north to Kummado soil wall(金馬都土城), south to the confluence of Iksan river(益山川) and Busang river(扶桑川), west to Okum mountain fortress(五金山城) and Galjeon river(葛田川), east to line near to eastern wall of Jesuksa temple(帝釋寺). Iksan ssang-reung(益山雙陵) was located outside western boundary line of capital city. Thirdly axis from Wangkung-ri castle to northern Kummado soil wall made a skeletal axis of city structure. It got through northern lowland along Buk river(北川) between Yonghwa(龍華山) and Mireuk mountain. Fourthly the location of royal palace can be deduced to the north part of the city around Kumma town area along the planning principle of northern royal palace.

Transportation Network Data Generation from the Topological Geographic Database (GIS위상구조자료로부터 교통망자료의 추출에 관한 연구)

  • 최기주
    • Spatial Information Research
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    • v.2 no.2
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    • pp.147-163
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    • 1994
  • This paper presents three methods of generating the transportation network data out of the topological geographic database in the hope that the conversion of the geographic database file containing the topology to the conventional node-link type trans¬portation network file may facilitate the integration between transportation planning mod¬els and GIS by alleviating the inherent problems of both computing environments. One way of the proposed conversion method is to use the conversion software that allows the bi-directional conversion between the UTPS (Urban Transportation Planning System) type transportation planning model and GIS. The other two methods of data structure conversion approach directly transform the GIS's user-level topology into the transportation network data topology, and have been introduced with codes programmed with FORTRAN and AML (Arc Macro Language) of ARC/INFO. If used successfully, any approach would not only improve the efficiency of transportation planning process and the associated decision-making activities in it, but enhance the productivity of trans¬portation planning agencies.

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Prediction of retention of uncharged solutes in nanofiltration by means of molecular descriptors

  • Nowaczyk, Alicja;Nowaczyk, Jacek;Koter, Stanislaw
    • Membrane and Water Treatment
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    • v.1 no.3
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    • pp.181-192
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    • 2010
  • A linear quantitative structure-property relationship (QSPR) model is presented for the prediction of rejection in permeation through membrane. The model was produced by using the multiple linear regression (MLR) technique on the database consisting of retention data of 25 pesticides in 4 different membrane separation experiments. Among the 3224 different physicochemical, topological and structural descriptors that were considered as inputs to the model only 50 were selected using several criteria of elimination. The physical meaning of chosen descriptor is discussed in detail. The accuracy of the proposed MLR models is illustrated using the following evaluation techniques: leave-one-out cross validation procedure, leave-many-out cross validation procedure and Y-randomization.

Incomplete 2-manifold Mesh Based Tool Path Generation (불완전한 2차원다양체 메시기반 공추경로생성)

  • Lee Sung-gun;Kim Su-jin;Yang Min-yang;Lee Dong-yoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.3 s.234
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    • pp.447-454
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    • 2005
  • This paper presents a new paradigm for 3-axis tool path generation based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral machining approach, the proposed method generates tool paths from an incomplete 2-manifold mesh model. In order to generate gouge-free tool paths, CL-meshes are generated by offsetting boundary edges, boundary vertices, and facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and verified by machining an incomplete 2-manifold mesh model.

Neural Network-based Decision Class Analysis with Incomplete Information

  • Kim, Jae-Kyeong;Lee, Jae-Kwang;Park, Kyung-Sam
    • Proceedings of the Korea Database Society Conference
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    • 1999.06a
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    • pp.281-287
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    • 1999
  • Decision class analysis (DCA) is viewed as a classification problem where a set of input data (situation-specific knowledge) and output data (a topological leveled influence diagram (ID)) is given. Situation-specific knowledge is usually given from a decision maker (DM) with the help of domain expert(s). But it is not easy for the DM to know the situation-specific knowledge of decision problem exactly. This paper presents a methodology fur sensitivity analysis of DCA under incomplete information. The purpose of sensitivity analysis in DCA is to identify the effects of incomplete situation-specific frames whose uncertainty affects the importance of each variable in the resulting model. For such a purpose, our suggested methodology consists of two procedures: generative procedure and adaptive procedure. An interactive procedure is also suggested based the sensitivity analysis to build a well-formed ID. These procedures are formally explained and illustrated with a raw material purchasing problem.

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Cutter Interference Avoidance in NC Machining of Compound Surfaces (복합곡면 NC 가공에서의 공구간섭 방지)

  • Jun, Cha-Soo
    • Journal of Korean Institute of Industrial Engineers
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    • v.19 no.3
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    • pp.139-154
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    • 1993
  • Cutter Interference(or part surface gouging) is one of the most critical problems in NC machining of sculptured surfaces. Presented in this paper is and algorithmic procedure that converts CC data obtained from a compound surface(several surfaces without topological relationship) into interference-free CL data. The interference handling procedure consists of following steps: (1) Z-map model is constructed from input surfaces. (2) Interference sources are detected using local properties of the sources. (3) Interference regions are completely identified based on global tests for neighboring CC points of the interference sources (4) Cutter paths are reconstructed after removing the CC data in interference regions, while avoiding any new interferences.

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A Study on the Development of Indoor Spatial Data Model Using CityGML ADE (CityGML ADE를 이용한 실내공간 데이터모델 개발에 관한 연구)

  • Kang, Hye Young;Hwang, Jung Rae;Lee, Ji Yeong
    • Spatial Information Research
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    • v.21 no.2
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    • pp.11-21
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    • 2013
  • W ith the recent increasing build and application for 3D spatial information, the importance of management and application for spatial information based on indoor space has been increased. Especially, Due to the increasing of the scale and complexity of the building according to the development of construction technologies several studies have been conducted to provide the services based on indoor space such as indoor navigation for disaster. Therefore, to efficient manage and service for information of complicated indoor space, it is necessary to extend and develop 3D spatial model and services that have been developed for outdoor space. In this paper, Indoor Spatial Data Model(ISDM) is developed to support building spatial information for complicated indoor space and location based services through topological information. ISDM contains a feature model which is a CityGML Application Domain Extension(ADE) model and a topology model that refers the IndoorGML.

Distribution of Photovoltaic Energy Including Topography Effect (지형 효과를 고려한 지표면 태양광 분포)

  • Jee, Joon-Bum;Zo, Il-Sung;Lee, Kyu-Tae;Choi, Young-Jean
    • Journal of the Korean earth science society
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    • v.32 no.2
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    • pp.190-199
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    • 2011
  • A photovoltaic energy map that included a topography effect on the Korean peninsula was developed using the Gangneung-Wonju National University (GWNU) solar radiation model. The satellites data (MODIS, OMI and MTSAT-1R) and output data from the Regional Data Assimilation Prediction System (RDAPS) model by the Korea Meteorological Administration (KMA) were used as input data for the GWNU model. Photovoltaic energy distributions were calculated by applying high resolution Digital Elevation Model (DEM) to the topography effect. The distributions of monthly accumulated solar energy indicated that differences caused by the topography effect are more important in winter than in summer because of the dependency on the solar altitude angle. The topography effect on photovoltaic energy is two times larger with 1 km resolution than with 4 km resolution. Therefore, an accurate calculation of the solar energy on the surface requires high-resolution topological data as well as high quality input data.