• 경영과학
• /
• 제14권1호
• /
• pp.205-227
• /
• 1997

Higher level representation splay an important role in model management systems. The role is to make decision makers friendly represent their problem using the representations. In this research, we address higher level representations including five distinctivenesses: Objective, Node, Link, Topological Constraint including five components, and Decision, Therefore, it is developed a system called HLRNET that implements the building procedure of network models using structural knowledge and object data The paper particularly elaborates all components included in each of distinctiveness extracted from structural characteristics of a lot of telecommunication network models. Higher level representations represented with five destinctivenesses should be converted into base level representations which are employed for semantic representations of linear and integer programming problems in a knowledge-assisted optimization modeling system. The system is illustrated with an example of the local access network model.

• ETRI Journal
• /
• 제31권1호
• /
• pp.31-41
• /
• 2009

Optical burst switching is a promising switching paradigm for the next IP-over-optical network backbones. However, its burst loss performance is greatly affected by burst contention. Several methods have been proposed to address this problem, some of them requiring the network to be flooded by frequent state dissemination signaling messages. In this work, we present a traffic engineering approach for path selection with the objective of minimizing contention using only topological information. The main idea is to balance the traffic across the network to reduce congestion without incurring link state dissemination protocol penalties. We propose and evaluate two path selection strategies that clearly outperform shortest path routing. The proposed path selection strategies can be used in combination with other contention resolution methods to achieve higher levels of performance and support the network reaching stability when it is pushed under stringent working conditions. Results show that the network connectivity is an important parameter to consider.

• 대한기계학회논문집A
• /
• 제30권8호
• /
• pp.906-915
• /
• 2006

This study concerns an advanced 3D surface reconstruction method that the vertices of surface model can be completely matched to the unstructured point cloud measured from arbitrary complex shapes. The concept of bounding voxel model is introduced to generate the mesh model well-representing the geometrical and topological characteristics of point cloud. In the reconstruction processes, the application of various methodologies such as shrink-wrapping, mesh simplification, local subdivision surface fitting, insertion of is isolated points, mesh optimization and so on, are required. Especially, the effectiveness, rapidity and reliability of the proposed surface reconstruction method are demonstrated by the simulation results for the geometrically and topologically complex shapes like dragon and human mouth.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
• /
• pp.1145-1149
• /
• 1990

This paper proposes a numerical method for redundant manipulators using predetermined optimal resolution. In order to obtain optimal joint trajectories, it is desirable to formulate redundancy resolution as an optimization problem having an integral cost criterion. We predetermine the trajectories of redundant joints in terms of the Nth partial sum of the Fourier series, which lead to the solution in the desirable homotopy class. Then optimal coefficients of the Fourier series, which yield the optimal solution within the predetermined class, are searched by the Powell's method. The proposed method is applied to a 3-link planar manipulator for cyclic tasks in Cartesian space. As the results, we can obtain the optimal solution in the desirable homotopy class without topological liftings of the solution. To show the validity of the proposed method, we analyze both optimal and extremal solutions by the Fast Fourier Transform (FFT) and discuss joint trajectories on the phase plane.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.651-652
• /
• 2008

This research presents a multi-objective optimal design employing topological approach to maximize magnetic energy while minimizing structural deformation which is caused by magnetic reluctance force and magnetostriction. A design sensitivity formula is derived by employing the adjoint variable method (AVM) to avoid numerous sensitivity evaluations for a coupled magneto-mechanical analysis. The sensitivity analysis is verified using the finite difference method (FDM) in a C-shape actuator. A linear actuator used in a home appliance is examined for optimal design and demonstrates the strength of the proposed topology optimization approach.

• Journal of Ship and Ocean Technology
• /
• 제9권1호
• /
• pp.47-63
• /
• 2005

In the present study, we suggest a new method for designing complex ship hull forms with multiple domain B-spline surfaces accounting for their topological arrangement, where all subdomains are fully defined in terms of form parameters, e.g., positional, differential and integral descriptors. For the construction of complex hull forms, free-form elementary models such as forebody, afterbody and bulbs are united by Boolean operation and blending surfaces in compliance with the sectional area curve (SAC) of the whole ship. This new design process in this paper is called Sectional Area Curve-Balanced Parametric Design (SAC-BPD).

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2003년도 추계학술발표논문집 (하)
• /
• pp.1429-1432
• /
• 2003

This paper addresses the problem of finding a constrained nearest neighbor for moving query point(we call it CNNMP) The Nearest neighbor problem is classified by existence of a constrained region, the number of query result and movement of query point and target. The problem assumes that the query point is not static, as 1-nearest neighbor problem, but varies its position over time to the constrained region. The parameters as NC, NCMBR, CQR and QL for the algorithm are also presented. We suggest the query optimization algorithm in consideration of topological relationship among them

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.138-139
• /
• 2007

This research provides machine designers with some intuition to consider both, magnetic and heat transfer effects. A topological multi-objective function includes magnetic energy and heat inflow rate to the system, which equals to the total heat dissipation by conduction and convection. For the thermal field regarding the heat inflow, introduced as a reaction force, topology design sensitivity is derived by employing discrete equations. The adjoint variable method is used to avoid numerous sensitivity evaluations. As a numerical example, a C-core design excited by winding current demonstrates the strength of the multi-physical approach.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제32권10호
• /
• pp.963-973
• /
• 2005

인터넷이 발전함에 따라 네트워크 시스템의 토폴로지 설계에 관한 여러 가지 문제들에 관심이 증가하고 있다. 이러한 네트워크의 토폴로지 구조는 서비스 센터, 터미널(사용자), 그리고 연결 케이블로 이뤄져 있으며 네트워크 시스템들은 사용자들로부터의 요구사항이 많아지고 있기에 주로 광케이블로 구축하는 경우가 점차 늘어나고 있다. 하지만, 광케이블의 고비용을 고려하면 네트워크의 구조가 스패닝 트리로 구축되어 지는 것이 바람직하다고 볼 수 있다. 본 논문에서는 연결비용, 평균 메시지 지연, 네트워크 신뢰도를 고려하여, 광케이블로 구성되는 광대역 통신 네트워크의 2기준 네트워크 토폴로지 설계 문제들을 풀기 위한 유전자 알고리즘을 제안한다. 또한, 후보 네트워크 토폴로지 구조를 염색체로 표현하기 위해 $Pr\ddot{u}fer$수(PN)와 클러스터 스트링으로 구성되는 새로운 인코딩 방법도 제안한다. 마지막으로 제안한 유전자 알고리즘이 계산 시간뿐만 아니라 파레토 최적성의 관점에서도 보다 효율적이며 효과적인 방법이라는 것을 수치예를 통해 살펴본다.

• 한국추진공학회지
• /
• 제13권1호
• /
• pp.51-57
• /
• 2009

이 연구 논문에서는 위상최적화 방법을 사용하여 강제대류를 이용한 열소산하는 구조물을 설계하는 방법을 개발한다. 전기 부품이나 기계구조물에서 발생하는 열을 낮추기 위해서 자연 대류와 강제 대류가 넓게 사용되고 있다. 또한 현재에는 화학전지(Fuel cell)나 로켓의 추진기관 등에서 발생한 열을 낮추기 위해서 강제 대류를 사용하고 있다. 현재에 이런 시스템을 효과적으로 열을 소산시키기 위해서 유동의 채널을 설계하는 것이 아주 중요한 이슈로 다루어지고 있다. 따라서 이 논문에서는 위상최적화 기법을 사용하여 최적의 채널을 설계하는 연구를 수행한다. 대류 현상을 고려하기 위해서 비압축성 N-S 방정식의 해석을 수행하였다. 이 논문에서는 열과 유체가 연계되어 있는 시스템을 수치적으로 연구하고 강제대류를 고려하는 최적의 채널 설계 결과를 제시한다.