The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

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

  • CVPR Workshops - Discontinuous Non-Rigid Motion Analysis of Sea Ice using C-Band Synthetic Aperture Radar Satellite Imagery
    2004 Conference on Computer Vision and Pattern Recognition Workshop, 2004
    Co-Authors: M. Thomas, Cathleen A. Geiger, C. Kambhamettu
    Abstract:

    Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior Arctic and Antarctic pack ice, the Continuum Assumption begins to fail below the 5 km scale with evidence of discontinuities already revealed in models and remote sensing products in the form of abrupt changes in magnitude and direction of the differential velocity. Using a hierarchical multi-scale phase-correlation method and profiting from known limitations of cross correlation methods, we incorporate the identification of discontinuities into our motion estimation algorithm, thereby descending below the Continuum threshold to examine the phenomenon of discontinuous non-rigid sea-ice motion.

  • Discontinuous Non-Rigid Motion Analysis of Sea Ice using C-Band Synthetic Aperture Radar Satellite Imagery
    2004 Conference on Computer Vision and Pattern Recognition Workshop, 2004
    Co-Authors: M. Thomas, C. Geiger, C. Kambhamettu
    Abstract:

    Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior Arctic and Antarctic pack ice, the Continuum Assumption begins to fail below the 5 km scale with evidence of discontinuities already revealed in models and remote sensing products in the form of abrupt changes in magnitude and direction of the differential velocity. Using a hierarchical multi-scale phase-correlation method and profiting from known limitations of cross correlation methods, we incorporate the identification of discontinuities into our motion estimation algorithm, thereby descending below the Continuum threshold to examine the phenomenon of discontinuous non-rigid sea-ice motion.

Orland W Kolling - One of the best experts on this subject based on the ideXlab platform.

  • dielectric Continuum Assumption applied to binary solvents containing acetonitrile with an aromatic cosolvent
    Transactions of the Kansas Academy of Science, 1995
    Co-Authors: Orland W Kolling
    Abstract:

    Cosolvent systems containing the polar acetonitrile (AN) paired with a nonpolar or slightly polar aromatic component represent an adjustable but relatively broad interval for bulk dielectric constant (2 to 36 at 250C). Trends in the Kirkwood, Block-Walker, Onsager, Brady-Carr, and Marcus Continuum functions for solvent mixtures were examined for the specific case of acetonitrile : toluene and these were compared to results for the isodielectric pair, ethyl-benzene: toluene. The influence assigned to polarizability by the aromatic species is significant and was quantified for twelve monosubstituted and disubstituted benzenes in binary mixtures having acetonitrile as the cosolvent in common.

  • the dielectric Continuum Assumption as a description of medium effects in binary solvent mixtures implications for electron transfer processes in cos olvent systems
    The Journal of Physical Chemistry, 1991
    Co-Authors: Orland W Kolling
    Abstract:

    Most physical models for solvent effects upon electron-transfer reactions represent the solvent role as a dielectric Continuum and incorporate the bulk solvent properties of dielectric constant and/or index of refraction into their solvent-dependent kinetics and thermodynamic terms. Because such models may fail quantitatively when applied to cosolvent mixtures, two isodielectric pairs were used as initial test systems to compare trends in classical Continuum functions with changing solvent composition

  • Binary Nonaqueous Solvent Systems Exhibiting Characteristics of Dielectric Continua
    Transactions of the Kansas Academy of Science, 1990
    Co-Authors: Orland W Kolling
    Abstract:

    The dielectric Continuum Assumption as a description of medium effects upon chemical processes often fails when applied to reactions in mixed solvents. Test specifications for the cosolvent as a Continuum are now stated in a more precise form and these make use of the Kirkwood-Onsager and Block-Walker functions in dielectric constant. As a result, two additional binary solvents have been identified which appear to meet the tests, namely the 1-butanol : 1-propanol and nitrobenzene : acetonitrile cosolvent systems. In modeling the influence of polar solvents upon both electrolytic conductance and reaction kinetics in nonaqueous media most contemporary theories have initially made use of the "dielectric Continuum Assumption" to represent the solvent environment (Covington and Dickinson, 1973). When stated in its simplest form (Amis, 1966), that Assumption depicts the solvent as being the fully homogeneous surroundings for all solute species including reactants, products and transition state structures involved in the given process. Likewise, it requires that the polarity of that Continuum be expressed as an appropriate function in either dielectric constant (E) alone or coupled with the square of the index of refraction for the bulk solvent. For the latter, the solvent reorganization energy functions of Marcus (1963) and their extension by Lay (1986) to hydrogen bonding solvents are representative of current Continuum descriptions which have been applied to electron transfer processes in solution. By-and-large, the dielectric Continuum Assumption serves best as a solvent environmental description for pure solvents of the aprotic dipolar (AD) and aprotic highly dipolar (AHD) classes in the Chastrette-Purcell (1985) general classification scheme. Beyond the discrete point (single solvent) tests of that Assumption, the model has been used with reactions in binary solvent mixtures, and it is in such cosolvent systems which serve as dielectrically tunable media that the Continuum Assumption is often quantitatively invalid. For mixed solvents, the failure of the model may arise from several sources at the molecular level. These include a range of solvent-solvent interactions from strong

Mary Ann Ingram - One of the best experts on this subject based on the ideXlab platform.

  • Alternating cooperative transmissions for a strip-shaped sensor network
    2010 44th Annual Conference on Information Sciences and Systems (CISS), 2010
    Co-Authors: Aravind Kailas, Mary Ann Ingram
    Abstract:

    We analyze a medium access control (MAC)-free ¿alternating sets¿ transmission strategy for a two-dimensional strip-shaped network. This may be viewed as a broadcast strategy if the entire network has a strip shape, or it may be viewed as a unicast strategy if there is a set of pre-designated cooperators along a conventional multi-hop route, which we refer to as a cooperative route. When there are repeated transmissions, the key advantage of the approach is that it drains the energies of the participating nodes uniformly and in an energy efficient fashion, thereby increasing the network longevity for energy constrained networks. The strategy is based on a very low-overhead form of cooperative diversity called the Opportunistic Large Array (OLA). In the initial transmission, an SNR (¿transmission¿) threshold is used to define mutually exclusive sets of nodes, such that the union of the sets includes all the nodes in the network or cooperative route. Only one of the sets is used for the first transmission. The next transmission uses the next set, and so on. In other words, for two sets, the proposed Alternating OLA with Transmission Threshold (A-OLA-T) basically alternates the transmitting set of nodes (or OLAs) during each transmission cycle. Previously, we analyzed A-OLA-T under the Continuum Assumption (very high node density) for disc-shaped networks. In this paper, we analyze the performance of the two-set A-OLA-T for strip-shaped networks.

  • Equitable Energy Consumption during Repeated Transmissions in a Multihop Wireless Network
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Aravind Kailas, Mary Ann Ingram
    Abstract:

    This paper addresses the issue of network life during repeated broadcasts originating from the same source in large, strip-shaped wireless sensor networks. The proposed technique would also apply to a unicast over a strip-shaped cooperative route within a network. The proposed medium access control (MAC)-free "alternating sets" transmission strategy is based on a very low- overhead form of cooperative diversity called the opportunistic large array (OLA). The proposed alternating OLA with transmission threshold (A-OLA-T) uses a received power-based threshold to define mutually exclusive sets of nodes, such that the union of the sets includes all the nodes in the network or cooperative route during the initial broadcast. A-OLA-T alternates the set of cooperators (or OLAs) during successive transmissions to reduce the energy consumption and the duty cycles of nodes (measured in terms of the percentage time a node is on and transmitting), thereby avoiding the formation of "hot spots" (regions of overuse, high energy consumption, and traffic) in the network. Under the Continuum Assumption (very high node density) for two-dimensional strip networks (or routes), we obtain lower bounds (as a function of the number of alternating sets, m) on the node degree for achieving optimal load balancing in the network, and, consequently, prolonging the network life.

  • Alternating opportunistic large arrays in broadcasting for network lifetime extension
    IEEE Transactions on Wireless Communications, 2009
    Co-Authors: Aravind Kailas, Mary Ann Ingram
    Abstract:

    We propose a protocol for broadcasting in wireless multihop networks that is based on a form of cooperative transmission called the opportunistic large array (OLA). An SNR ("transmission") threshold is used to define two mutually exclusive sets of OLAs, such that the union of the sets includes all the nodes in the network. The broadcast protocol then alternates between the sets for each broadcast and is called Alternating OLA with Transmission Threshold (A-OLA-T). Under A-OLAT, all participating nodes transmit with the same low power, therefore the energies of the nodes in the network drain efficiently and uniformly, extending the network life relative to broadcasts that use simple OLA or non-alternating OLAs with a transmission threshold. In this paper, we optimize the A-OLA-T protocol under the Continuum Assumption (very high node density).

  • GLOBECOM - Alternating Cooperative Transmission for Energy-Efficient Broadcasting
    IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008
    Co-Authors: Aravind Kailas, Mary Ann Ingram
    Abstract:

    We propose a broadcast protocol that is based on a form of cooperative diversity called the opportunistic large array (OLA). In the initial broadcast, an SNR ("transmission") threshold is used to define mutually exclusive sets of OLAs, such that the union of the sets includes all the nodes in the network. The broadcast protocol then basically alternates the transmitting set of nodes (or OLAs) during each broadcast cycle and is called alternating OLA with transmission threshold (A- OLA-T). Under A-OLA-T, broadcasting drains the energies of the nodes in the network efficiently and uniformly, extending the network life relative to broadcasts that use simple OLA or non-alternating OLAs with a transmission threshold. In this paper, we optimize the A-OLA-T protocol under the Continuum Assumption (very high node density).

  • Alternating Cooperative Transmission for Energy-Efficient Broadcasting
    IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008
    Co-Authors: Aravind Kailas, Mary Ann Ingram
    Abstract:

    We propose a broadcast protocol that is based on a form of cooperative diversity called the opportunistic large array (OLA). In the initial broadcast, an SNR ("transmission") threshold is used to define mutually exclusive sets of OLAs, such that the union of the sets includes all the nodes in the network. The broadcast protocol then basically alternates the transmitting set of nodes (or OLAs) during each broadcast cycle and is called alternating OLA with transmission threshold (A- OLA-T). Under A-OLA-T, broadcasting drains the energies of the nodes in the network efficiently and uniformly, extending the network life relative to broadcasts that use simple OLA or non-alternating OLAs with a transmission threshold. In this paper, we optimize the A-OLA-T protocol under the Continuum Assumption (very high node density).

Haiqiang Wu - One of the best experts on this subject based on the ideXlab platform.

  • a numerical molecular dynamics approach for squeeze film damping of perforated mems structures in the free molecular regime
    Microfluidics and Nanofluidics, 2014
    Co-Authors: Pu Li, Yuming Fang, Haiqiang Wu
    Abstract:

    Accurate determination of the squeeze-film damping in rare air is crucial for the design of high-Q MEMS devices. In the past, for the MEMS structures with no perforations, there have been two approaches to treating the squeeze-film damping in rare air: the approach based on the Continuum Assumption and the approach using molecular dynamics (MD) method. The amount of squeeze-film damping can be controlled by providing perforations in microstructures. To model perforation effects on squeeze-film damping, many methods have been proposed. However, almost all the previous methods are based on the Continuum Assumption. Only one paper focuses on analytical modeling of squeeze-film damping of a perforated microplate using the MD method. Hutcherson and Ye (J Micromech Microeng 14:1726–1733, 2004) developed a novel MD method to model the squeeze-film damping in free molecular regime. The method possesses high computational efficiency. However, their work is valid only for non-perforated rectangular microplate. This paper presents a numerical MD approach for calculating the squeeze-film damping of a perforated rectangular plate and a perforated circular plate in free molecular regime. In Hutcherson and Ye’s work, the microplate is non-perforated. After each collision with the non-perforated plate, all the molecules are reflected to the substrate. In this paper, the plate is perforated. For the molecules in the air gap striking the surface of the perforated microplate, some of the molecules are reflected to the substrate. The rest leave the air gap through the perforations. This paper is an extension of the work done by Hutcherson and Ye (J Micromech Microeng 14:1726–1733, 2004). The accuracy of the present numerical MD approach is verified by comparing its results with the experimental results available in the literature and the finite element method results.

M. Thomas - One of the best experts on this subject based on the ideXlab platform.

  • CVPR Workshops - Discontinuous Non-Rigid Motion Analysis of Sea Ice using C-Band Synthetic Aperture Radar Satellite Imagery
    2004 Conference on Computer Vision and Pattern Recognition Workshop, 2004
    Co-Authors: M. Thomas, Cathleen A. Geiger, C. Kambhamettu
    Abstract:

    Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior Arctic and Antarctic pack ice, the Continuum Assumption begins to fail below the 5 km scale with evidence of discontinuities already revealed in models and remote sensing products in the form of abrupt changes in magnitude and direction of the differential velocity. Using a hierarchical multi-scale phase-correlation method and profiting from known limitations of cross correlation methods, we incorporate the identification of discontinuities into our motion estimation algorithm, thereby descending below the Continuum threshold to examine the phenomenon of discontinuous non-rigid sea-ice motion.

  • Discontinuous Non-Rigid Motion Analysis of Sea Ice using C-Band Synthetic Aperture Radar Satellite Imagery
    2004 Conference on Computer Vision and Pattern Recognition Workshop, 2004
    Co-Authors: M. Thomas, C. Geiger, C. Kambhamettu
    Abstract:

    Sea-ice motion consists of complex non-rigid motions involving continuous, piece-wise continuous and discrete particle motion. Techniques for estimating non-rigid motion of sea ice from pairs of satellite images (generally spaced three days apart) are still in the developmental stages. For interior Arctic and Antarctic pack ice, the Continuum Assumption begins to fail below the 5 km scale with evidence of discontinuities already revealed in models and remote sensing products in the form of abrupt changes in magnitude and direction of the differential velocity. Using a hierarchical multi-scale phase-correlation method and profiting from known limitations of cross correlation methods, we incorporate the identification of discontinuities into our motion estimation algorithm, thereby descending below the Continuum threshold to examine the phenomenon of discontinuous non-rigid sea-ice motion.