• Title/Summary/Keyword: Topology Changes

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Material Topology Optimization Design of Structures using SIMP Approach Part II : Initial Design Domain with Topology of Partial Solids (SIMP를 이용한 구조물의 재료 위상 최적설계 Part II : 부분적인 솔리드 위상을 가지는 초기 설계영역)

  • Lee, Dong-Kyu;Park, Sung-Soo;Shin, Soo-Mi
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.1
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    • pp.19-28
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    • 2007
  • Discrete topology optimization processes of structures start from an initial design domain which is described by the topology of constant material densities. During optimization procedures, the structural topology changes in order to satisfy optimization problems in the fixed design domain, and finally, the optimization produces material density distributions with optimal topology. An introduction of initial holes in a design domain presented by Eschenauer et at. has been utilized in order to improve the optimization convergence of boundary-based shape optimization methods by generating finite changes of design variables. This means that an optimal topology depends on an initial topology with respect to topology optimization problems. In this study, it is investigated that various optimal topologies can be yielded under constraints of usable material, when partial solid phases are deposited in an initial design domain and thus initial topology is finitely changed. As a numerical application, structural topology optimization of a simple MBB-Beam is carried out, applying partial circular solid phases with varying sizes to an initial design domain.

Hierarchical Topology/parameter Evolution in Engineering Design

  • Seo Ki sung
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2005.04a
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    • pp.185-188
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    • 2005
  • This paper suggests a control method for efficient topology/parameter evolution in a bond-graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems, We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.

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Changes in Sea Bottom Topology with Saemangeurn Project (새만금사업에 따른 해저 지형변화)

  • Choi, Jin-Kyu;Son, Jae-Gwon;Kim, Jeong-Gyun;Song, Ki-Il
    • Journal of Korean Society of Rural Planning
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    • v.8 no.2 s.16
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    • pp.17-26
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    • 2002
  • The purpose of this study was to investigate the changes of the sea bottom topology during construction of Saemangeum seadikes. Sea water depth and bottom topology in the Saemangeum area were measured every year and the surveyed data under construction of Saemangeum seadikes were analyzed and compared to the initial conditions before construction, There was erosion in the overall surveyed areas and the depth of erosion was approximately 53cm compared to the data in 1988. The center sandbanks of Seadike 2 did not show the great changes due to two main channels those were developed in northeast and southeast. The inland sandbanks of Seadike 4 showed the development of great erosion and deposition partially because of the changes in tide direction which developed as a result of the completion of Seadike 3 and the completion of a seadike of the Kunsan-Changhang industrial park at the north of Saemangeumm area.

An Efficient Topology/Parameter Control in Evolutionary Design for Multi-domain Engineering Systems

  • Seo, Ki-Sung
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.2
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    • pp.108-113
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    • 2005
  • This paper suggests a control method for an efficient topology/parameter evolution in a bond graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems. We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach in bond graph synthesis, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.

Deployment Dynamics of Large-Scale Flexible Solar Arrays with Deployable Mast

  • LI, Hai-Quan;LIU, Xiao-Feng;GUO, Shao-Jing;CAI, Guo-Ping
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.2
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    • pp.245-254
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    • 2017
  • In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.

An Expert System for Fault Section Diagnosis in Power Systems using the information including operating times of actuated relays and tripped circuit breakers (보호 계전기와 차단기의 동작 순서를 고려한 전력 시스템 사고 구간 진단을 위한 전문가 시스템)

  • Min, S.W.;Lee, S.H.;Park, J.K.
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.125-127
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    • 2000
  • Multiple faults are hard to diagnose correctly because the operation of circuit breakers tripped by former fault changes the topology of power systems. The information including operating time of actuated relays and tripped circuit breakers is used for considering changes of the network topology in fault section diagnosis. This paper presents a method for fault section diagnosis using a set of matrices which represent changes of the network topology due to operation of circuit breakers. The proposed method uses fuzzy relation to cope with the unavoidable uncertainties imposed on fault section diagnosis of power systems. The inference executed by the proposed matrices provides the fault section candidates in the form of a matrix made up of the degree of membership. Experimental studies for real power systems reveal usefulness of the proposed technique to diagnose multiple faults.

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A Reconfiguration Technique of Logical Topology in a Ship Backbone Network (선박 백본 네트워크의 논리 토폴로지 재구성 기법)

  • Tak, Sung-Woo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.5
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    • pp.922-931
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    • 2012
  • This paper studies a series of logical topology reconfiguration processes corresponding to a series of traffic demand changes in a ship backbone network. The proposed reconfiguration technique is to minimize costly changes of traffic forwarding paths and minimize the average hop distance of traffic forwarding paths in terms of ship backbone network performance simultaneously. Performance evaluation is conducted to illustrate the efficiency of the proposed reconfiguration technique. It shows that the proposed reconfiguration technique yields efficient performance in the entire series of reconfiguration processes.

Prediction of the Future Topology of Internet Reflecting Non-monotony (비단조 변화성을 이용한 인터넷의 미래 위상 예측)

  • 조인숙;이문호
    • Journal of Information Technology Applications and Management
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    • v.11 no.2
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    • pp.205-214
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    • 2004
  • Internet evolves into the huge network with new nodes inserted or deleted depending on specific situations. A new model of network topology is needed in order to analyze time-varying Internet more realistically and effectively. In this study the non-monotony models are proposed which can describe topological changes of Internet such as node insertion and deletion, and can be used for predicting its future topology. Simulation is performed to analyze the topology generated by our model. Simulation results show that our proposed model conform the power law of realistic Internet better than conventional ones. The non-monotony model can be utilized for designing Internet protocols and networks with better security.

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Opportunistic Data Relay Scheme for Narrowband Multihop Combat Radio Networks (협대역 다중홉 전투무선망에서 기회적 데이터 중계 기법)

  • Lee, Jongkwan
    • Journal of the Korea Institute of Military Science and Technology
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    • v.25 no.1
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    • pp.65-71
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    • 2022
  • In this paper, we propose an opportunistic data relay scheme in narrowband multihop combat radio networks. Narrowband networks have physical restrictions on high-speed transmission. Furthermore, the topology changes dynamically due to the jamming of the enemy, signal interference between friendly forces, and movement of network entities. Therefore, the traditional relay scheme that collects topology information and calculates a relay path before transmission is unsuitable for such networks. Our proposed scheme does not collect topology information and transmits data opportunistically. The scheme can cause unnecessary data relaying that is not related to data delivery to the destination node. However, for small networks, the effect of increasing network throughput by not gathering topology information is much greater than the effect of reducing throughput by unnecessary data relays. We demonstrate the performance superiority of the proposed scheme through simulation in the worst case of network topology.

On the Association Between Sub-photospheric Flows and Photospheric Magnetic Fields of Solar Active Regions

  • Maurya, Ram Ajor;Chae, Jong-Chul
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.86.2-86.2
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    • 2012
  • We present the study of association between sub-photospheric flow and photospheric magnetic fields of active regions respectively derived from the local helioseismology and observed magnetic fields. It is believed that the energetic transients, e.g., flares and CMES, are caused by changes in magnetic and velocity field topologies in solar atmosphere. These changes are essentially brought about by the magnetic fields that are rooted beneath the photosphere where they interact and get affected by sub-photospheric flows. Therefore, we expect the topology of sub-surface flows to be correlated with the observable topology of magnetic fields at the photosphere and higher layers. In order to examine the correlation, if any, we computed the near photospheric flows and photospheric magnetic fields using the Doppler velocity and magnetic fields observations, respectively, provided by the SDO/HMI. The high resolution Doppler observations from the HMI enabled us to compute the very high p-modes parameters which sample the sub-photosphere shallow near the photosphere. Furthermore, we compute the sub-photospheric flow topology parameters, e.g., vorticity, kinetic helicity, and photospheric magnetic field topology parameters, e.g., magnetic helicity, from the magnetic fields observations to compare their associations. We present the result of the analysis in the paper.

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