• 로봇학회논문지
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• 제6권2호
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• pp.189-196
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• 2011

This paper presents a method of topological modeling using only low-cost sonar sensors. The proposed method constructs a topological model by extracting sub-regions from the local grid map. The extracted sub-regions are considered as nodes in the topological model, and the corresponding edges are generated according to the connectivity between two sub-regions. A grid confidence for each occupied grid is evaluated to obtain reliable regions in the local grid map by filtering out noisy data. Moreover, a convexity measure is used to extract sub-regions automatically. Through these processes, the topological model is constructed without predefining the number of sub-regions in advance and the proposed method guarantees the convexity of extracted sub-regions. Unlike previous topological modeling methods which are appropriate to the corridor-like environment, the proposed method can give a reliable topological modeling in a home environment even under the noisy sonar data. The performance of the proposed method is verified by experimental results in a real home environment.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제12권3호
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• pp.169-178
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• 2005

In this paper we study the existence and local asymptotic limit of the topological Chern-Simons vortices of the CP(1) model in $\mathbb{R}^2$. After reducing to semilinear elliptic partial differential equations, we show the existence of topological solutions using iteration and variational arguments & prove that there is a sequence of topological solutions which converges locally uniformly to a constant as the Chern­Simons coupling constant goes to zero and the convergence is exponentially fast.

• 대한수학회보
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• 제48권5호
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• pp.1111-1117
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• 2011

Using the moving plane method, we establish the radial symmetry of topological one-vortex solutions of a semilinear elliptic system arising from the self-dual Maxwell-Chern-Simons O(3) model.

• 대한수학회논문집
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• 제19권2호
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• pp.283-291
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• 2004

In this paper we show the radial symmetry of topological one-vortex solutions in the Maxwell-Chern-Simons-Higgs Model.

• Spatial Information Research
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• 제19권1호
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• pp.93-105
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• 2011

최근 들어 건축과 IT 기술이 발전함에 따라서 대규모의 복잡한 3차윈 공간이 증가하고 있고, 사람들 또한 이러한 공간에서 생활하는 시간이 늘어나고 있는 추세이다. 이에 따라 복잡한 3차원 공간 내에서 유사시를 대비한 또는 편의 정보를 제공하기 위한 서비스가 필요하게 되었고, 이러한 서비스를 제공하기 위해서는 복잡한 공간에서의 효율적인 위상학적 관계성 파악이 기본적으로 뒷받침이 되어야 한다. 공간의 관계성 파악은 위상학적 관계를 저장하고 표현하는 각각의 데이터 모델에 따라 그 방법과 효율성이 달라진다. 위상학적 관계성 저장과 표현에 있어서 가장 널리 사용되어 왔던 데이터 모델은 B-rep 기반의 데이터 모델이고, 2000년대 초반에 들어서는 네트워크 기반 위상학적 데이터 모델에 관한 연구가 많이 진행되었다. 본 연구에서는 데이터 저장 용량 및 공간질의에 대하여 두 데이터 모델의 효율성을 검증한다. 효율성은 데이터의 저장용량, 인접성 및 연결성 질의 응답속도를 기준으로 하여 수행한다. 효율성 검증의 결과로써 네트워크 기반 위상학적 데이터 모델이 3차원 공간질의에 있어서 B-rep 기반 데이터 모델 보다 효율성이 높음을 제시한다.

• 로봇학회논문지
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• 제4권1호
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• pp.25-33
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• 2009

One of the main problems of topological localization in a real indoor environment is variations in the environment caused by dynamic objects and changes in illumination. Another problem arises from the sense of topological localization itself. Thus, a robot must be able to recognize observations at slightly different positions and angles within a certain topological location as identical in terms of topological localization. In this paper, a possible solution to these problems is addressed in the domain of global topological localization for mobile robots, in which environments are represented by their visual appearance. Our approach is formulated on the basis of a probabilistic model called the Bayes filter. Here, marginalization of dynamics in the environment, marginalization of viewpoint changes in a topological location, and fusion of multiple visual features are employed to measure observations reliably, and action-based view transition model and action-associated topological map are used to predict the next state. We performed experiments to demonstrate the validity of our proposed approach among several standard approaches in the field of topological localization. The results clearly demonstrated the value of our approach.

• 한국정밀공학회지
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• 제13권7호
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• pp.100-114
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• 1996

In order to create a solid model more efficiently for a plastic or sheet metal product with a thin and constant thickness, various methods have been proposed up to now. One of the most typical approaches is to create a sheet model initially and then transform it into a solid model automatically for a given thickness. The sheet model as well as the transitive model in sheet modeling procedure is a non-manifold model. However, the previous methods adopted the boundary representations for a solid model as their topological framework. Thus, it is difficult to represent the exact adjacency relationship between topological entities and to implement the topological operations for sheet modeling and the transformation procedure of a sheet into a solid. In this paper, we proposed a sheet modeling system based on a non-manifold topological representation which can represent solids, sheets, wireframes, and their mixture. A set of generalized Euler operators for non-manifold topology as well as the sheet modeling capabilities including adding, bending, and punching functions are provided for easy modeling of sheet objects, and they are perfomed interactively with a two dimensional curve editor. Once a sheet model is completed, it can be transformed into a solid automatically. The transformation procedure is composed of the offset functions and the Boolean operations of sheet models, and it is even more comprehensive and easier to be implemented than the precious methods.

• Computers and Concrete
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• 제17권1호
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• pp.141-156
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• 2016

The search for new structural systems capable of associating performance and safety requires deeper knowledge regarding the mechanical behavior of structures subject to different loading conditions. The Strut-and-Tie Model is commonly used to structurally designing some reinforced concrete elements and for the regions where geometrical modifications and stress concentrations are observed, called "regions D". This method allows a better structural behavior representation for strength mechanisms in the concrete structures. Nonetheless, the topological model choice depends on the designer's experience regarding compatibility between internal flux of loads, geometry and boundary/initial conditions. Thus, there is some difficulty in its applications, once the model conception presents some uncertainty. In this context, the present work aims to apply the Strut-and-Tie Model to nonlinear structural elements together with a topological optimization method. The topological optimization method adopted considers the progressive stiffness reduction of finite elements with low stress values. The analyses performed could help the structural designer to better understand structural conceptions, guaranteeing the safety and the reliability in the solution of complex problems involving structural concrete.

• Spatial Information Research
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• 제3권2호
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• pp.191-204
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• 1995

데이타 모델(data model)이란 실세계에 대한 공간 및 비공간적 특성(feature)을 추상화한 시스템 모델이다. 각 시스템들을 고유한 데이타 모델을 통해 외부 세계에 대한 내부 표현및 외부 세계와의 접속관계에 대한 틀(framework)을 정의하게 되며, 공간 질의어는 지리 정보시스템에서 정의하고 있는 외부 세계화의 접속 관계를 우한 효과적인 틀의 하나이다. 기존의 지리 정보 시스템에서는 관계형 데이타 모델에 기반한 공간 데이타 모델들이 주로 사용되었으므로 데이타 추상화(abstraction)및 상속 (inheritance)을 통한 복합 객체의 표현에 문제점이 있었다. 본 논문에서는 ODMG의 객체 모델을 기반으로 평면 위상 모델 (planar topological model)을 수용하여 객체지향 데이타 모델인 위상 객체 모델(Topological Object Model : TOM)을 제안하고, 이를 기반으로 객체지향 공간 질의어인 OQL/Geo을 설계하였다. OQL/Geo은 ODMG에 의해 개발된 질의어인 OQL을 기반으로 하여 위상 객체 모델을 효과적으로 표현할 수 있도록 확장하였으며, 기하연산, 위상연산및 가시연산등의 풍부한 연산자들을 제공하고 있으며, 복잡한 공간 분석에 대한 요구 뿐 아니라 질의 결과에 대한 출력 형식도 다양하게 표현할 수 있도록 하였다.

• International Journal of CAD/CAM
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• 제5권1호
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• pp.59-68
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• 2005

Euclidean Voronoi diagram of spheres in 3-dimensional space has not been explored as much as it deserves even though it has significant potential impacts on diverse applications in both science and engineering. In addition, studies on the data structure for its topology have not been reported yet. Presented in this, paper is the topological representation for Euclidean Voronoi diagram of spheres which is a typical non-manifold model. The proposed representation is a variation of radial edge data structure capable of dealing with the topological characteristics of Euclidean Voronoi diagram of spheres distinguished from those of a general non-manifold model and Euclidean Voronoi diagram of points. Various topological queries for the spatial reasoning on the representation are also presented as a sequence of adjacency relationships among topological entities. The time and storage complexities of the proposed representation are analyzed.