• 제목/요약/키워드: Geometric Representation

검색결과 205건 처리시간 0.025초

밀집한 신경망 그래프 기반점운의 분류 (Dense Neural Network Graph-based Point Cloud classification)

  • 아메드 엘 카자리;이효종
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2019년도 춘계학술발표대회
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    • pp.498-500
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    • 2019
  • Point cloud is a flexible set of points that can provide a scalable geometric representation which can be applied in different computer graphic task. We propose a method based on EdgeConv and densely connected layers to aggregate the features for better classification. Our proposed approach shows significant performance improvement compared to the state-of-the-art deep neural network-based approaches.

지리-객체와 지리-필드에서 기하 속성과 공간관계 역할에 기반한 객체 지향 공간 데이터 모델 (An Object Oriented Spatial Data Model Based on Geometric attributes and the Role of Spatial Relationships in Geo-objects and Geo-fields)

  • 이홍로
    • 정보처리학회논문지D
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    • 제8D권5호
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    • pp.516-572
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    • 2001
  • 지리정보시스템은 다양한 분야에서 응용할 수 있는 자료를 다루고 있다. 각 용용 분야를 위한 필요한 정보는 지리정보의 설계 단계에서 지리영역의 응용관점에 따라 다르게 표현될 수 있다. 그러므로 지리정보시스템은 지리현상에서 발생하는 각 객체의 독립성과 동질성 여부에 따라 표현해야 한다. 이 논문은 지리-객체, 지리-필드와 비지리-객체 상에서 속성과 관계 역할에 대한 정의와 정리를 통한 형식화에 대해 연구되었다. 이를 위해 지리-객체는 지리-필드와 비지리-객체의 관계역할에 대한 형식화 관점에서 재구성되었다. 이 연구 결과 이 논문은 공간 클래스의 정적상태 특성인 속성-영역 관계를 공간 관계 역할로 표현하고, 형식화함으로써 기하 속성과 공간 관계 역할에 기반한 지리정보시스템의 효율적 설계의 방법을 제시하였다.

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쉘 곡면 형상의 최적 설계를 위한 유한요소해석과 기하학적 모델링의 연동 (Development of Framework of Linkage between Geometric Modeling and Finite Element Analysis for Shape Optimization of Shell Surfaces)

  • 김현철;노희열;조맹효
    • 한국항공우주학회지
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    • 제31권8호
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    • pp.27-35
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    • 2003
  • 쉘의 기하 모델링과 해석은 각각 다른 배경과 목적을 가지고 발전되어 왔다. 따라서 기하 모델링과 해석을 통합한 설계 도구를 만들기에 기존의 방법은 적절하지 않다. 본 연구에서는 기하 모델링과 해석, 최적 설계를 통합한 개념을 제시한다. 이것은 B-스플라인 곡면의 표현방법에 기초를 두고 있다. 기하학적으로 정확한 쉘 유한요소를 도입하였으며, 최적 설계 부분에서는 곡면의 조정점을 설계변수로 택하였다. 또한 설계 민감도를 계산하기 위해서 준해석적 방법을 사용했고, 이를 바탕으로 순차적 선형계획법을 이용해 곡면의 형상 최적화를 수행하였다. 이렇게 개발된 통합설계 개념은 곡면의 모델링과 해석에 적합한 도구로 이용될 수 있다.

Nonlinear dynamic performance of long-span cable-stayed bridge under traffic and wind

  • Han, Wanshui;Ma, Lin;Cai, C.S.;Chen, Suren;Wu, Jun
    • Wind and Structures
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    • 제20권2호
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    • pp.249-274
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    • 2015
  • Long-span cable-stayed bridges exhibit some features which are more critical than typical long span bridges such as geometric and aerodynamic nonlinearities, higher probability of the presence of multiple vehicles on the bridge, and more significant influence of wind loads acting on the ultra high pylon and super long cables. A three-dimensional nonlinear fully-coupled analytical model is developed in this study to improve the dynamic performance prediction of long cable-stayed bridges under combined traffic and wind loads. The modified spectral representation method is introduced to simulate the fluctuating wind field of all the components of the whole bridge simultaneously with high accuracy and efficiency. Then, the aerostatic and aerodynamic wind forces acting on the whole bridge including the bridge deck, pylon, cables and even piers are all derived. The cellular automation method is applied to simulate the stochastic traffic flow which can reflect the real traffic properties on the long span bridge such as lane changing, acceleration, or deceleration. The dynamic interaction between vehicles and the bridge depends on both the geometrical and mechanical relationships between the wheels of vehicles and the contact points on the bridge deck. Nonlinear properties such as geometric nonlinearity and aerodynamic nonlinearity are fully considered. The equations of motion of the coupled wind-traffic-bridge system are derived and solved with a nonlinear separate iteration method which can considerably improve the calculation efficiency. A long cable-stayed bridge, Sutong Bridge across the Yangze River in China, is selected as a numerical example to demonstrate the dynamic interaction of the coupled system. The influences of the whole bridge wind field as well as the geometric and aerodynamic nonlinearities on the responses of the wind-traffic-bridge system are discussed.

현대건축 형태생성 과정으로써의 유형학적 특성 (Typology as Form Generating Process in Contemporary Architecture)

  • 김종명;김동진
    • 한국실내디자인학회논문집
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    • 제23권5호
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    • pp.3-13
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    • 2014
  • Typology in Contemporary Architecture wants to escape from the classical typology that has the problems about specific program of structuralism, typical repeatation of customary form. As visible and non-visible things are appeared in contemporary architecture through the analysis of the inner system involving development process of changing itself, typology of contemporary is utilized at a tool of form generation in the process of architect. And it notes that the structural properties of the building system. The form of contemporary architecture has the new connecting strucure not reduced to existing ones. It carries out generative access as a device in order to solve the complexity of society. From this perspective, we analyze the process of projects of contemporary architects that can be typological strategy not representation of post geometric form but a tool of form generation in architectural process. As a result, we can find four characteristics of typology as a tool of form generation; 'interference and mix of program', 'continous slabs', 'rearrangement through relationship setting', 'transformation of multi-layers'. These are expanding to the process that reflect history and context or infer from morphology. Therefore, typology as architectural process of form generation overcomes morphological typology of classical typology and suggests that the different architectural approach having potential possibility.

THE CURVATURE TENSORS IN THE EINSTEIN'S $^*g$-UNIFIED FIELD THEORY II. THE CONTRACTED SE-CURVATURE TENSORS OF $^*g-SEX_n$

  • Chung, Kyung-Tae;Chung, Phil-Ung;Hwang, In-Ho
    • 대한수학회보
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    • 제35권4호
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    • pp.641-652
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    • 1998
  • Chung and et al. ([2].1991) introduced a new concept of a manifold, denoted by $^{\ast}g-SEX_n$, in Einstein's n-dimensional $^{\ast}g$-unified field theory. The manifold $^{\ast}g-SEX_n$ is a generalized n-dimensional Riemannian manifold on which the differential geometric structure is imposed by the unified field tensor $^{\ast}g^{\lambda \nu}$ through the SE-connection which is both Einstein and semi-symmetric. In this paper, they proved a necessary and sufficient condition for the unique existence of SE-connection and sufficient condition for the unique existence of SE-connection and presented a beautiful and surveyable tensorial representation of the SE-connection in terms of the tensor $^{\ast}g^{\lambda \nu}$. Recently, Chung and et al.([3],1998) obtained a concise tensorial representation of SE-curvature tensor defined by the SE-connection of $^{\ast}g-SEX_n$ and proved deveral identities involving it. This paper is a direct continuations of [3]. In this paper we derive surveyable tensorial representations of constracted curvature tensors of $^{\ast}g-SEX_n$ and prove several generalized identities involving them. In particular, the first variation of the generalized Bianchi's identity in $^{\ast}g-SEX_n$, proved in theorem (2.10a), has a great deal of useful physical applications.

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고 정밀 항공우주 유동해석 및 설계를 위한 공력계산 툴 (Essential Computational Tools for High-Fidelity Aerodynamic Simulation and Design)

  • 김종암
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.33-36
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    • 2006
  • As the computing environment is rapidly improved, the interests of CFD are gradually focused on large-scale computation over complex geometry. Keeping pace with the trend, essential computational tools to obtain solutions of complex aerospace flow analysis and design problems are examined. An accurate and efficient flow analysis and design codes for large-scale aerospace problem are presented in this work. With regard to original numerical schemes for flow analysis, high-fidelity flux schemes such as RoeM, AUSMPW+ and higher order interpolation schemes such as MLP (Multi-dimensional Limiting Process) are presented. Concerning the grid representation method, a general-purpose basis code which can handle multi-block system and overset grid system simultaneously is constructed. In respect to design optimization, the importance of turbulent sensitivity is investigated. And design tools to predict highly turbulent flows and its sensitivity accurately by fully differentiating turbulent transport equations are presented. Especially, a new sensitivity analysis treatment and geometric representation method to resolve the basic flow characteristics are presented. Exploiting these tools, the capability of the proposed approach to handle complex aerospace simulation and design problems is tested by computing several flow analysis and design problems.

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통계적 모멘트를 이용한 정확한 환경 지도 표현을 위한 저가 라이다 센서 기반 유리 특징점 추출 기법 (A Low-Cost Lidar Sensor based Glass Feature Extraction Method for an Accurate Map Representation using Statistical Moments)

  • 안예찬;이승환
    • 로봇학회논문지
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    • 제16권2호
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    • pp.103-111
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    • 2021
  • This study addresses a low-cost lidar sensor-based glass feature extraction method for an accurate map representation using statistical moments, i.e. the mean and variance. Since the low-cost lidar sensor produces range-only data without intensity and multi-echo data, there are some difficulties in detecting glass-like objects. In this study, a principle that an incidence angle of a ray emitted from the lidar with respect to a glass surface is close to zero degrees is concerned for glass detection. Besides, all sensor data are preprocessed and clustered, which is represented using statistical moments as glass feature candidates. Glass features are selected among the candidates according to several conditions based on the principle and geometric relation in the global coordinate system. The accumulated glass features are classified according to the distance, which is lastly represented on the map. Several experiments were conducted in glass environments. The results showed that the proposed method accurately extracted and represented glass windows using proper parameters. The parameters were empirically designed and carefully analyzed. In future work, we will implement and perform the conventional SLAM algorithms combined with our glass feature extraction method in glass environments.

숫자 또는 도형을 사용하여 제시된 비정형적인 문제에서 학생들의 반응에 대한 연구 (A Study on Students' Responses to Non-routine Problems Using Numerals or Figures)

  • 황선욱;심상길
    • 한국수학교육학회지시리즈A:수학교육
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    • 제49권1호
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    • pp.39-51
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    • 2010
  • The purpose of this article is to study students' responses to non-routine problems which are presented by using solely numerals or symbolic figures. Such figures have no mathematical meaning but just symbolical meaning. Most students understand geometric figures more concrete objects than numerals because geometric figures such as circles and squares can be visualized by the manipulatives in real life. And since students need not consider (unvisible) any operational structure of numerals when they deal with (visible) figures, problems proposed using figures are considered relatively easier to them than those proposed using numerals. Under this assumption, we analyze students' problem solving processes of numeral problems and figural problems, and then find out when students' difficulties arise in the problem solving process and how they response when they feel difficulties. From this experiment, we will suggest several comments which would be considered in the development and application of both numerical and figural problems.