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Chen Jie-yun - One of the best experts on this subject based on the ideXlab platform.

Shu-cherng Fang - One of the best experts on this subject based on the ideXlab platform.

  • The Point-to-Point Connection problem—analysis and algorithms
    Discrete Applied Mathematics, 1997
    Co-Authors: Madan Natu, Shu-cherng Fang
    Abstract:

    Abstract The Point-to-Point Connection problem is to find a subset of arcs with minimal total cost connecting a fixed number of source-destination pairs. The problem has many variations for different applications. In this paper, we focus on a case where the source-destination pairs are prematched. We examine the structure of the problem with two source-destination pairs and provide an efficient implementation of a Dijkstra-like algorithm with time complexity O (mn + n 2 log n) . We also provide a dynamic programming algorithm with complexity O (n 11 ) for the case with three source-destination pairs. We conjecture that the same approach can be generalized for p source-destination pairs with complexity O (n 3p + 2 ) where p is fixed.

  • On the Point-to-Point Connection problem
    Information Processing Letters, 1995
    Co-Authors: Madan Natu, Shu-cherng Fang
    Abstract:

    Abstract A Dijkstra-like algorithm for solving the Point-to-Point Connection problem on a finite directed network is presented. For this problem we find a subset of arcs with minimal total length connecting a fixed number of source-destination pairs. The problem has many variations for different applications. We focus on a case where two source-destination pairs are prematched and show that the time complexity of the algorithm is O ( n 4 ).

Madan Natu - One of the best experts on this subject based on the ideXlab platform.

  • The Point-to-Point Connection problem—analysis and algorithms
    Discrete Applied Mathematics, 1997
    Co-Authors: Madan Natu, Shu-cherng Fang
    Abstract:

    Abstract The Point-to-Point Connection problem is to find a subset of arcs with minimal total cost connecting a fixed number of source-destination pairs. The problem has many variations for different applications. In this paper, we focus on a case where the source-destination pairs are prematched. We examine the structure of the problem with two source-destination pairs and provide an efficient implementation of a Dijkstra-like algorithm with time complexity O (mn + n 2 log n) . We also provide a dynamic programming algorithm with complexity O (n 11 ) for the case with three source-destination pairs. We conjecture that the same approach can be generalized for p source-destination pairs with complexity O (n 3p + 2 ) where p is fixed.

  • The Point-to-Point Connection problem — analysis and algorithms
    Discrete Applied Mathematics, 1997
    Co-Authors: Madan Natu, Fang Shu-cherng
    Abstract:

    AbstractThe Point-to-Point Connection problem is to find a subset of arcs with minimal total cost connecting a fixed number of source-destination pairs. The problem has many variations for different applications. In this paper, we focus on a case where the source-destination pairs are prematched. We examine the structure of the problem with two source-destination pairs and provide an efficient implementation of a Dijkstra-like algorithm with time complexity O(mn + n2 log n). We also provide a dynamic programming algorithm with complexity O(n11) for the case with three source-destination pairs. We conjecture that the same approach can be generalized for p source-destination pairs with complexity O(n3p + 2) where p is fixed

  • On the Point-to-Point Connection problem
    Information Processing Letters, 1995
    Co-Authors: Madan Natu, Shu-cherng Fang
    Abstract:

    Abstract A Dijkstra-like algorithm for solving the Point-to-Point Connection problem on a finite directed network is presented. For this problem we find a subset of arcs with minimal total length connecting a fixed number of source-destination pairs. The problem has many variations for different applications. We focus on a case where two source-destination pairs are prematched and show that the time complexity of the algorithm is O ( n 4 ).

Hong Zhou - One of the best experts on this subject based on the ideXlab platform.

  • The Uncertainty Elimination in Discrete Topology Optimization of Compliant Mechanisms
    Volume 6A: 37th Mechanisms and Robotics Conference, 2013
    Co-Authors: Hong Zhou, Satya Raviteja Kandala
    Abstract:

    Topology uncertainty leads to different topology solutions and makes topology optimization ambiguous. Point Connection and grey cell might cause topology uncertainty. They are both eradicated when hybrid discretization model is used for discrete topology optimization. A common topology uncertainty in the current discrete topology optimization stems from mesh dependence. The topology solution of an optimized compliant mechanism might be uncertain when its design domain is discretized differently. To eliminate topology uncertainty from mesh dependence, the genus based topology optimization strategy is introduced in this paper. The topology of a compliant mechanism is defined by its genus which is the number of holes in the compliant mechanism. With this strategy, the genus of an optimized compliant mechanism is actively controlled during its topology optimization process. There is no topology uncertainty when this strategy is incorporated into discrete topology optimization. The introduced topology optimization strategy is demonstrated by examples with different degrees of genus.Copyright © 2013 by ASME

  • The Discrete Topology Optimization of Structures Using the Modified Quadrilateral Discretization Model
    Volume 2: 32nd Computers and Information in Engineering Conference Parts A and B, 2012
    Co-Authors: Hong Zhou, Ravinder G. Malela
    Abstract:

    The modified quadrilateral discretization model is introduced for the discrete topology optimization of structures in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical or diagonal direction. Point Connection is eradicated. In the proposed discrete topology optimization method of structures, design variables are all binary and every design cell is either solid or void to prevent grey cell problem that is caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the optimized structure safe. The binary bit-array genetic algorithm is used to search for the optimal topology to circumvent the geometrical bias against the vertical design cells. No postprocessing is needed for topology uncertainty caused by Point Connection or grey cell. The presented discrete topology optimization procedure is illustrated by two topology optimization examples of structures.Copyright © 2012 by ASME

  • The Modified Quadrilateral Discretization Model for the Topology Optimization of Compliant Mechanisms
    Journal of Mechanical Design, 2011
    Co-Authors: Hong Zhou, Pranjal P. Killekar
    Abstract:

    The modified quadrilateral discretization model for the topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical, or diagonal direction. Point Connection is completely eliminated. In the proposed topology optimization method, design variables are all binary, and every design cell is either solid or void to prevent gray cell problem that is usually caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum. No postprocessing is required for topology uncertainty caused by either Point Connection or gray cell. The presented modified quadrilateral discretization model and the proposed topology optimization procedure are demonstrated by two synthesis examples of compliant mechanisms.

  • The Modified Quadrilateral Discretization Model for the Topology Optimization of Compliant Mechanisms
    Volume 6: 35th Mechanisms and Robotics Conference Parts A and B, 2011
    Co-Authors: Hong Zhou, Pranjal P. Killekar
    Abstract:

    The modified quadrilateral discretization model for the topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical or diagonal direction. Point Connection is completely eliminated. In the proposed topology optimization method, design variables are all binary and every design cell is either solid or void to prevent grey cell problem that is usually caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum and avoid the need to select the initial guess solution and conduct sensitivity analysis. No postprocessing is needed for topology uncertainty caused by Point Connection or grey cell. The presented modified quadrilateral discretization model and the proposed topology optimization procedure are demonstrated by two synthesis examples of compliant mechanisms.Copyright © 2011 by ASME

  • The Comparision of Hybrid and Quadrilateral Discretization Models for the Topology Optimization of Compliant Mechanisms
    Volume 7: Dynamic Systems and Control; Mechatronics and Intelligent Machines Parts A and B, 2011
    Co-Authors: Hong Zhou, Nitin M. Dhembare
    Abstract:

    The design domain of a synthesized compliant mechanism is discretized into quadrilateral design cells in both hybrid and quadrilateral discretization models. However, quadrilateral discretization model allows for Point Connection between two diagonal design cells. Hybrid discretization model completely eliminates Point Connection by subdividing each quadrilateral design cell into triangular analysis cells and connecting any two contiguous quadrilateral design cells using four triangular analysis cells. When Point Connection is detected and suppressed in quadrilateral discretization, the local topology search space is dramatically reduced and slant structural members are serrated. In hybrid discretization, all potential local Connection directions are utilized for topology optimization and any structural members can be smooth whether they are in the horizontal, vertical or diagonal direction. To compare the performance of hybrid and quadrilateral discretizations, the same design and analysis cells, genetic algorithm parameters, constraint violation penalties are employed for both discretization models. The advantages of hybrid discretization over quadrilateral discretization are obvious from the results of two classical synthesis examples of compliant mechanisms.Copyright © 2011 by ASME

S C Horii - One of the best experts on this subject based on the ideXlab platform.

  • introduction to the acr nema dicom standard
    Radiographics, 1992
    Co-Authors: W. Dean Bidgood, S C Horii
    Abstract:

    In 1982, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) formed a committee to develop standards for the interConnection of digital imaging devices. Version 1.0 of the standard, published in 1985, specifies a hardware interface supporting Point-to-Point (not network) image transmission, a data dictionary (a set of rules for encoding information), and a set of commands to initiate transactions. Version 2.0, published in 1988, also addresses Point-to-Point image transmission and provides semantic rules by which messages (streams of bits representing information in transit from one device to another) are organized. Version 3.0, also referred to as DICOM (Digital Imaging and Communications in Medicine), will be finalized in 1992. The DICOM standard encourages open systems interConnection of imaging equipment over standard networks, while maintaining compatibility with earlier Point-to-Point Connection standards. The DICOM standard conforms fully with the In...

  • introduction to the acr nema dicom standard
    Radiographics, 1992
    Co-Authors: W. Dean Bidgood, S C Horii
    Abstract:

    In 1982, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) formed a committee to develop standards for the interConnection of digital imaging devices. Version 1.0 of the standard, published in 1985, specifies a hardware interface supporting Point-to-Point (not network) image transmission, a data dictionary (a set of rules for encoding information), and a set of commands to initiate transactions. Version 2.0, published in 1988, also addresses Point-to-Point image transmission and provides semantic rules by which messages (streams of bits representing information in transit from one device to another) are organized. Version 3.0, also referred to as DICOM (Digital Imaging and Communications in Medicine), will be finalized in 1992. The DICOM standard encourages open systems interConnection of imaging equipment over standard networks, while maintaining compatibility with earlier Point-to-Point Connection standards. The DICOM standard conforms fully with the International Standards Organization reference model for network communications (ISORM), addresses the issue of conformance, and incorporates the concept of object-oriented design.