The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
R.m. Gray - One of the best experts on this subject based on the ideXlab platform.
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A Lagrangian Formulation of fixed-rate quantization
Data Compression Conference, 2005Co-Authors: R.m. GrayAbstract:A Lagrangian Formulation of fixed-rate vector quantization is presented. The Formulation provides an alternative version of the classic high-rate quantization approximations for fixed-rate codes of Zador (1966), and Bucklew and Wise (1982) which parallels the Lagrangian results for variable-rate codes and it leads to a variation of the classic Lloyd (1982) algorithm for quantizer design. The approach also leads to a natural Lagrangian Formulation combining both common rate constraints of alphabet size and entropy, effectively providing a Lagrangian Formulation of memory and entropy constrained vector quantization.
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DCC - A Lagrangian Formulation of fixed-rate quantization
Data Compression Conference, 2005Co-Authors: R.m. GrayAbstract:A Lagrangian Formulation of fixed-rate vector quantization is presented. The Formulation provides an alternative version of the classic high-rate quantization approximations for fixed-rate codes of Zador (1966), and Bucklew and Wise (1982) which parallels the Lagrangian results for variable-rate codes and it leads to a variation of the classic Lloyd (1982) algorithm for quantizer design. The approach also leads to a natural Lagrangian Formulation combining both common rate constraints of alphabet size and entropy, effectively providing a Lagrangian Formulation of memory and entropy constrained vector quantization.
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A Lagrangian Formulation of high rate quantization
2001 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings (Cat. No.01CH37221), 2001Co-Authors: J. Shih, A.k. Aiyer, R.m. GrayAbstract:The asymptotic optimal performance of variable-rate vector quantizers of fixed dimension and large rate was first developed in a rigorous fashion by Paul Zador (1966). Subsequent design algorithms for such compression codes used a Lagrangian Formulation in order to generalize Lloyd's classic quantizer optimization algorithm to variable rate codes. This Formulation has been subsequently adopted in a variety of practical systems including rate-optimized streaming video. We describe a Lagrangian Formulation of Zador's variable-rate quantization results and apply it to estimate Zador's constant using the generalized Lloyd algorithm.
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ICASSP - A Lagrangian Formulation of high rate quantization
2001 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings (Cat. No.01CH37221), 2001Co-Authors: J. Shih, A.k. Aiyer, R.m. GrayAbstract:The asymptotic optimal performance of variable-rate vector quantizers of fixed dimension and large rate was first developed in a rigorous fashion by Paul Zador (1966). Subsequent design algorithms for such compression codes used a Lagrangian Formulation in order to generalize Lloyd's classic quantizer optimization algorithm to variable rate codes. This Formulation has been subsequently adopted in a variety of practical systems including rate-optimized streaming video. We describe a Lagrangian Formulation of Zador's variable-rate quantization results and apply it to estimate Zador's constant using the generalized Lloyd algorithm.
Kees Vuik - One of the best experts on this subject based on the ideXlab platform.
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discontinuities in the Lagrangian Formulation of the kinematic wave model
Transportation Research Part C-emerging Technologies, 2013Co-Authors: Femke Van Wageningenkessels, Hans Van Lint, S P Hoogendoorn, Yufei Yuan, Kees VuikAbstract:In this article we demonstrate how network components can be modeled using the kinematic wave model in the Lagrangian Formulation. This includes modeling nodes (or discontinuities) such as inflow and outflow boundaries, merges and bifurcations (e.g. ramps) and nonhomogeneous roads. Nodes are usually fixed in space. This makes their implementation in Lagrangian coordinates where the coordinates move with the vehicle more complex than in Eulerian coordinates where the coordinates are fixed in space. To this end we derive an analytical node model. The article then discusses how to implement such sink and source terms in a discretized version of the kinematic wave model in Lagrangian coordinates. In this implementation several choices have to be made. Test results show that even with the most simple choices (discretization based on full vehicle groups and discrete time steps) accurate and plausible results are obtained. We conclude that the Lagrangian Formulation can successfully be applied for simulation of networks of nonhomogeneous roads.
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Lagrangian Formulation of multiclass kinematic wave model
Transportation Research Record, 2010Co-Authors: Femke Van Wageningenkessels, Hans Van Lint, S P Hoogendoorn, Kees VuikAbstract:The kinematic wave model is often used in simulation tools to describe dynamic traffic flow and to estimate and predict traffic states. Discretization of the model is generally based on Eulerian coordinates, which are fixed in space. However, the Lagrangian coordinate system, in which the coordinates move with the velocity of the vehicles, results in more accurate solutions. Furthermore, if the model includes multiple user classes, it describes real traffic more accurately. Such a multiclass model, in contrast to a mixed-class model, treats different types of vehicles (e.g., passenger cars and trucks or vehicles with different origins or destinations, or both) differently. The Lagrangian coordinate system is combined with a multiclass model, and a Lagrangian Formulation of the kinematic wave model for multiple user classes is proposed. It is shown that the advantages of the Lagrangian Formulation also apply for the multiclass model. Simulations based on the Lagrangian Formulation result in more accurate s...
Eugenio Onate - One of the best experts on this subject based on the ideXlab platform.
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Lagrangian Formulation for finite element analysis of quasi incompressible fluids with reduced mass losses
International Journal for Numerical Methods in Fluids, 2014Co-Authors: Eugenio Onate, Alessandro Franci, Josep Maria CarbonellAbstract:SUMMARY We present a Lagrangian Formulation for finite element analysis of quasi-incompressible fluids that has excellent mass preservation features. The success of the Formulation lays on a new residual-based stabilized expression of the mass balance equation obtained using the finite calculus method. The governing equations are discretized with the FEM using simplicial elements with equal linear interpolation for the velocities and the pressure. The merits of the Formulation in terms of reduced mass loss and overall accuracy are verified in the solution of 2D and 3D quasi-incompressible free-surface flow problems using the particle FEM (www.cimne.com/pfem). Examples include the sloshing of water in a tank, the collapse of one and two water columns in rectangular and prismatic tanks, and the falling of a water sphere into a cylindrical tank containing water. Copyright © 2014 John Wiley & Sons, Ltd.
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unified Lagrangian Formulation for elastic solids and incompressible fluids application to fluid structure interaction problems via the pfem
Computer Methods in Applied Mechanics and Engineering, 2008Co-Authors: Sergio Idelsohn, J Marti, Alejandro Cesar Limache, Eugenio OnateAbstract:Abstract We present a general Lagrangian Formulation for treating elastic solids and quasi/fully incompressible fluids in a unified form. The Formulation allows to treat solid and fluid subdomains in a unified manner in fluid–structure interaction (FSI) situations. In our work the FSI problem is solved via the particle finite element method (PFEM). The PFEM is an effective technique for modeling complex interactions between floating and submerged bodies and free surface flows, accounting for splashing of waves, large motions of the bodies and frictional contact conditions. Applications of the unified Lagrangian Formulation to a number of FSI problems are given.
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Unified Lagrangian Formulation for elastic solids and incompressible fluids: Application to fluid–structure interaction problems via the PFEM
Computer Methods in Applied Mechanics and Engineering, 2008Co-Authors: Sergio Idelsohn, J Marti, Alejandro Cesar Limache, Eugenio OnateAbstract:Abstract We present a general Lagrangian Formulation for treating elastic solids and quasi/fully incompressible fluids in a unified form. The Formulation allows to treat solid and fluid subdomains in a unified manner in fluid–structure interaction (FSI) situations. In our work the FSI problem is solved via the particle finite element method (PFEM). The PFEM is an effective technique for modeling complex interactions between floating and submerged bodies and free surface flows, accounting for splashing of waves, large motions of the bodies and frictional contact conditions. Applications of the unified Lagrangian Formulation to a number of FSI problems are given.
I. L. Buchbinder - One of the best experts on this subject based on the ideXlab platform.
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Lagrangian Formulation of the massive higher spin supermultiplets in three dimensional space time
arXiv: High Energy Physics - Theory, 2015Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:We give explicit construction for massive higher spin supermultiplets for the case of minimal supersymmetry in d=3 and find the corresponding Lagrangian Formulations. We show that all such massive supermultiplets can be straightforwardly constructed out of the appropriately chosen set of massless ones exactly in the same way as the gauge invariant description for the massive bosonic (fermionic) field with spin s can be obtained using a set of massless fields with spins s,s-1,...,0(1/2). Moreover, such construction for the massive supermultiplets turns out to be perfectly consistent with our previous results on the gauge invariant Lagrangian Formulation for massive higher spin bosons and fermions in d=3.
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frame like gauge invariant Lagrangian Formulation of massive fermionic higher spin fields in ads3 space
Physics Letters B, 2014Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:Abstract We construct the frame-like gauge-invariant Lagrangian Formulation for massive fermionic arbitrary spin fields in three-dimensional AdS space. The Lagrangian and complete set of gauge transformations are obtained. We also develop the formalism of gauge-invariant curvatures for the massive theory under consideration and show how the Lagrangian is formulated in their terms. The massive spin-5/2 field is discussed as an example.
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gauge invariant Lagrangian Formulation of massive higher spin fields in a ds 3 space
Physics Letters B, 2012Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:Abstract We develop the frame-like Formulation of massive bosonic higher spin fields in the case of three-dimensional ( A ) dS space with the arbitrary cosmological constant. The Formulation is based on gauge invariant description by involving the Stueckelberg auxiliary fields. The explicit form of the Lagrangians and the gauge transformation laws are found. The theory can be written in terms of gauge invariant objects similar to the massless theories, thus allowing us to hope to use the same methods for investigation of interactions. In the massive spin 3 field example we are able to rewrite the Lagrangian using the new the so-called separated variables, so that the study of Lagrangian Formulation reduces to finding the Lagrangian containing only half of the fields. The same construction takes places for arbitrary integer spin field as well. Further working in terms of separated variables, we build Lagrangian for arbitrary integer spin and write it in terms of gauge invariant objects. Also, we demonstrate how to restore the full set of variables, thus receiving Lagrangian for the massive fields of arbitrary spin in the terms of initial fields.
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ON MANIFOLDS ADMITTING THE CONSISTENT Lagrangian Formulation FOR HIGHER SPIN FIELDS
Modern Physics Letters A, 2011Co-Authors: I. L. Buchbinder, V.a. Krykhtin, P. M. LavrovAbstract:We study a possibility of Lagrangian Formulation for free massive higher spin bosonic totally symmetric tensor field on the background manifold characterizing by the arbitrary metric, vector and third-rank tensor fields in the framework of BRST approach. Assuming analytical dependence on the mass, curvatures and the other background fields in the Lagrangian and using the most general linearized ansatz for transversality condition, we prove that the consistent Formulation is possible only in constant curvature space and that there is only a trivial possibility to include the vector and third-rank tensor in the theory. This result finally proves that the consistent Lagrangian Formulation at the conditions under consideration is possible only in constant curvature Riemann space.
Yu M Zinoviev - One of the best experts on this subject based on the ideXlab platform.
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Lagrangian Formulation of the massive higher spin supermultiplets in three dimensional space time
arXiv: High Energy Physics - Theory, 2015Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:We give explicit construction for massive higher spin supermultiplets for the case of minimal supersymmetry in d=3 and find the corresponding Lagrangian Formulations. We show that all such massive supermultiplets can be straightforwardly constructed out of the appropriately chosen set of massless ones exactly in the same way as the gauge invariant description for the massive bosonic (fermionic) field with spin s can be obtained using a set of massless fields with spins s,s-1,...,0(1/2). Moreover, such construction for the massive supermultiplets turns out to be perfectly consistent with our previous results on the gauge invariant Lagrangian Formulation for massive higher spin bosons and fermions in d=3.
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frame like gauge invariant Lagrangian Formulation of massive fermionic higher spin fields in ads3 space
Physics Letters B, 2014Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:Abstract We construct the frame-like gauge-invariant Lagrangian Formulation for massive fermionic arbitrary spin fields in three-dimensional AdS space. The Lagrangian and complete set of gauge transformations are obtained. We also develop the formalism of gauge-invariant curvatures for the massive theory under consideration and show how the Lagrangian is formulated in their terms. The massive spin-5/2 field is discussed as an example.
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gauge invariant Lagrangian Formulation of massive higher spin fields in a ds 3 space
Physics Letters B, 2012Co-Authors: I. L. Buchbinder, T V Snegirev, Yu M ZinovievAbstract:Abstract We develop the frame-like Formulation of massive bosonic higher spin fields in the case of three-dimensional ( A ) dS space with the arbitrary cosmological constant. The Formulation is based on gauge invariant description by involving the Stueckelberg auxiliary fields. The explicit form of the Lagrangians and the gauge transformation laws are found. The theory can be written in terms of gauge invariant objects similar to the massless theories, thus allowing us to hope to use the same methods for investigation of interactions. In the massive spin 3 field example we are able to rewrite the Lagrangian using the new the so-called separated variables, so that the study of Lagrangian Formulation reduces to finding the Lagrangian containing only half of the fields. The same construction takes places for arbitrary integer spin field as well. Further working in terms of separated variables, we build Lagrangian for arbitrary integer spin and write it in terms of gauge invariant objects. Also, we demonstrate how to restore the full set of variables, thus receiving Lagrangian for the massive fields of arbitrary spin in the terms of initial fields.
