The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Susumu Itoh - One of the best experts on this subject based on the ideXlab platform.
-
lossless coding using variable block size adaptive Prediction optimized for each image
European Signal Processing Conference, 2005Co-Authors: Ichiro Matsuda, Nau Ozaki, Yuji Umezu, Susumu ItohAbstract:This paper proposes an efficient lossless coding scheme for still images. The scheme employs a block-adaptive Prediction Technique to remove spatial redundancy in a given image. The resulting Prediction errors are encoded using context-adaptive arithmetic coding. Several coding parameters, which must be sent to a decoder as side information, are iteratively optimized for each image so that the number of coding bits including the side information can have a minimum. Moreover, quadtree-based variable block-size partitioning is introduced into the above adaptive Prediction Technique. Experimental results show that the proposed coding scheme attains the best coding performance among the current state-of-the-art lossless coding schemes.
-
lossless coding using predictors and arithmetic code optimized for each image
Lecture Notes in Computer Science, 2003Co-Authors: Ichiro Matsuda, Noriyuki Shirai, Susumu ItohAbstract:This paper proposes an efficient lossless coding scheme for still images. The scheme utilizes a block-adaptive Prediction Technique to effectively remove redundancy in a given image. The resulting Prediction errors are encoded using a kind of context-adaptive arithmetic coding method. In order to improve coding efficiency, a generalized Gaussian function is used as a probability distribution model of the Prediction errors in each context. Moreover, not only the predictors but also parameters of the probability distribution models are iteratively optimized for each image so that a coding rate of the Prediction errors can have a minimum. Experimental results show that an average coding rate of the proposed coding scheme is close to 90% of that of JPEG-LS and is lower than that of TMW.
Yu Lei - One of the best experts on this subject based on the ideXlab platform.
-
a time series based precopy approach for live migration of virtual machines
International Conference on Parallel and Distributed Systems, 2011Co-Authors: Zhou Lei, Yu LeiAbstract:As an important Technique for load balancing in cloud computing, live migration of virtual machines has received increasing attention in recent years. One key issue of live migration of virtual machine is how to quickly and transparently migrate virtual machines to meet Service Level Agreements (SLAs). In this paper, we evaluate traditional precopy approach, and propose an improved time-series based precopy approach for virtual machine migration. With the time-series Prediction Technique, we identify frequently updated dirty pages (high dirty pages) in the past and future period more precisely, and transmit them in the last round of iteration, in order to reduce unnecessary, repeated transmission of dirty pages. Doing so can significantly reduce the total migration time. Simulation results show that compared with the traditional approach of Xen, our approach can effectively improve the performance of virtual machine migration, including less number of iterations, less down time and migration time, and fewer pages transferred.
Wim Desmet - One of the best experts on this subject based on the ideXlab platform.
-
an efficient wave based Prediction Technique for dynamic plate bending problems with corner stress singularities
Computer Methods in Applied Mechanics and Engineering, 2009Co-Authors: Caroline Vanmaele, Dirk Vandepitte, Wim DesmetAbstract:The Finite Element Method is commonly used for simulations of dynamic plate bending problems. A major disadvantage of this method is its practical frequency limitation in that the computational loads become prohibitively large at higher frequencies. A newly developed Wave Based Prediction Technique aims to relax this frequency limitation through an enhanced computational efficiency. This paper discusses the application of the Wave Based Method for the particular case where stress singularities appear in one or more corners of a polygonal plate domain. In this case the conventional set of field variable expansion functions is extended with some special-purpose functions which incorporate the corner point singularities. The beneficial convergence rate of the Wave Based Method as compared with the Finite Element Method is verified for various validation examples.
-
an efficient wave based Prediction Technique for plate bending vibrations
Computer Methods in Applied Mechanics and Engineering, 2007Co-Authors: Caroline Vanmaele, Dirk Vandepitte, Wim DesmetAbstract:The finite element method is a commonly used Prediction method for dynamic simulations of plate bending problems. A major disadvantage of this method is its practical frequency limitation as its application involves prohibitively large computational efforts at higher frequencies. A newly developed wave based Prediction Technique pushes up the frequency limit through an enhanced computational efficiency. This paper discusses the principles of the wave based method for convex plate problems. The beneficial convergence rate of the wave based method as compared with the finite element method is verified for various validation examples, which include the most commonly encountered boundary conditions.
-
on the use of a wave based Prediction Technique for steady state structural acoustic radiation analysis
Proceedings of the International Workshop on MeshFree Methods, 2003Co-Authors: Bert Pluymers, Wim Desmet, Dirk Vandepitte, Paul SasAbstract:Conventional element based methods for modelling structural-acoustic radia- tion problems are limited to low-frequency applications. Recently a novel Prediction tech- nique has been developed based on the Tretz approach. This new wave based method is computationally more ecient than the element based methods and, as a consequence, can tackle problems also at higher frequencies. This paper discusses the basic principals of the new method and illustrates its performance for the two-dimensional radiation analysis of a bass-reflex loudspeaker.
-
a computationally efficient Prediction Technique for the steady state dynamic analysis of coupled vibro acoustic systems
Advances in Engineering Software, 2002Co-Authors: Wim Desmet, B Van Hal, Paul Sas, Dirk VandepitteAbstract:A new Prediction Technique has been developed for the steady-state dynamic analysis of coupled vibro-acoustic systems. In contrast with the finite element method, in which the dynamic field variables within each element are expanded in terms of local, non-exact shape functions, the dynamic field variables are expressed as global wave function expansions, which exactly satisfy the governing dynamic equations. The contributions of the wave functions to the coupled vibro-acoustic response result from an integral formulation of the boundary conditions.This paper describes the basic concept of the new Technique for the modelling of the vibro-acoustic coupling between the pressure field in an acoustic cavity with arbitrary shape and the out-of-plane displacement of a flat plate with arbitrary shape. It is illustrated through a three-dimensional validation example that the new Prediction Technique yields a high accuracy with a substantially smaller computational effort than the finite element method, so that the new Prediction Technique can be applied up to much higher frequencies.
Ichiro Matsuda - One of the best experts on this subject based on the ideXlab platform.
-
lossless coding using variable block size adaptive Prediction optimized for each image
European Signal Processing Conference, 2005Co-Authors: Ichiro Matsuda, Nau Ozaki, Yuji Umezu, Susumu ItohAbstract:This paper proposes an efficient lossless coding scheme for still images. The scheme employs a block-adaptive Prediction Technique to remove spatial redundancy in a given image. The resulting Prediction errors are encoded using context-adaptive arithmetic coding. Several coding parameters, which must be sent to a decoder as side information, are iteratively optimized for each image so that the number of coding bits including the side information can have a minimum. Moreover, quadtree-based variable block-size partitioning is introduced into the above adaptive Prediction Technique. Experimental results show that the proposed coding scheme attains the best coding performance among the current state-of-the-art lossless coding schemes.
-
lossless coding using predictors and arithmetic code optimized for each image
Lecture Notes in Computer Science, 2003Co-Authors: Ichiro Matsuda, Noriyuki Shirai, Susumu ItohAbstract:This paper proposes an efficient lossless coding scheme for still images. The scheme utilizes a block-adaptive Prediction Technique to effectively remove redundancy in a given image. The resulting Prediction errors are encoded using a kind of context-adaptive arithmetic coding method. In order to improve coding efficiency, a generalized Gaussian function is used as a probability distribution model of the Prediction errors in each context. Moreover, not only the predictors but also parameters of the probability distribution models are iteratively optimized for each image so that a coding rate of the Prediction errors can have a minimum. Experimental results show that an average coding rate of the proposed coding scheme is close to 90% of that of JPEG-LS and is lower than that of TMW.
George V Lauder - One of the best experts on this subject based on the ideXlab platform.
-
a pressure based force and torque Prediction Technique for the study of fish like swimming
PLOS ONE, 2017Co-Authors: Kelsey N Lucas, John O Dabiri, George V LauderAbstract:Many outstanding questions about the evolution and function of fish morphology are linked to swimming dynamics, and a detailed knowledge of time-varying forces and torques along the animal's body is a key component in answering many of these questions. Yet, quantifying these forces and torques experimentally represents a major challenge that to date prevents a full understanding of fish-like swimming. Here, we develop a method for obtaining these force and torque data non-invasively using standard 2D digital particle image velocimetry in conjunction with a pressure field algorithm. We use a mechanical flapping foil apparatus to model fish-like swimming and measure forces and torques directly with a load cell, and compare these measured values to those estimated simultaneously using our pressure-based approach. We demonstrate that, when out-of-plane flows are relatively small compared to the planar flow, and when pressure effects sufficiently dominate shear effects, this Technique is able to accurately reproduce the shape, magnitude, and timing of locomotor forces and torques experienced by a fish-like swimmer. We conclude by exploring of the limits of this approach and its feasibility in the study of freely-swimming fishes.
