The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Vahid Tarokh - One of the best experts on this subject based on the ideXlab platform.
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GLOBECOM - An Exponential Model for Evaluating Error Performance of Turbo Codes
2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:In this paper, an Exponential Model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed Exponential Model offers a simple but effective method to approximate the waterfall region performance of Turbo codes, which is generally intricate for analytical bounding techniques. By combining the proposed Exponential Model with the well known union bound estimate, the paper derives a combined performance Model to extend the performance estimate within moderate to high SNR region. Moreover, it is shown that, only the free distance term of the weight spectrum is not always enough for a reasonable estimate of the error floor region performance, especially when the free distance multiplicity is small. Numerical results are presented to validate the applicability of the proposed performance Model.
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An Exponential Model for Evaluating Error Performance of Turbo Codes
2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:In this paper, an Exponential Model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed Exponential Model offers a simple but effective method to approximate the waterfall region performance of Turbo codes, which is generally intricate for analytical bounding techniques. By combining the proposed Exponential Model with the well known union bound estimate, the paper derives a combined performance Model to extend the performance estimate within moderate to high SNR region. Moreover, it is shown that, only the free distance term of the weight spectrum is not always enough for a reasonable estimate of the error floor region performance, especially when the free distance multiplicity is small. Numerical results are presented to validate the applicability of the proposed performance Model.
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On the performance estimate for Turbo codes
2010 International Conference on Wireless Communications & Signal Processing (WCSP), 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:Recently, the scaling law has been extended to approximate the waterfall performance for Turbo codes over the binary erasure channel. However, the waterfall approximation over other channels, such as the AWGN and Rayleigh fading channels, is still unknown for Turbo codes. In this paper, an Exponential Model was proposed to approximate the waterfall performance for Turbo codes. The relationship between the proposed Exponential Model and the scaling law will be highlighted at first. Our analysis unveils that the proposed Exponential Model could be regarded as a generalized scaling law Model, which makes it possible to achieve better performance estimate. The results in this paper explicitly shows that, the Exponential Model offers reasonable waterfall approximation for both word error probability and bit error probability for all packet sizes over a diverse channel, such as the binary erasure channel, the additive white Gaussian noise channel as well as the Rayleigh fading channel. The complete performance Model could be derived by combining the Exponential Model and the known union bound Model. Finally, some further discussions are presented to highlight the performance estimate problem for Turbo codes.
B B Verma - One of the best experts on this subject based on the ideXlab platform.
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prediction of fatigue crack growth and residual life using an Exponential Model part i constant amplitude loading
International Journal of Fatigue, 2009Co-Authors: J R Mohanty, B B VermaAbstract:In the present investigation an attempt has been made to introduce a life prediction methodology by adopting an ‘Exponential Model’ that can be used without integration of fatigue crack growth rate curve. The predicted results are compared with experimental crack growth data obtained for 7020-T7 and 2024-T3 aluminum alloy specimens under constant amplitude loading. It is observed that the results obtained from this Model are in good agreement with experimental data and cover both stage-II and stage-III of fatigue crack growth curve.
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prediction of fatigue crack growth and residual life using an Exponential Model part ii mode i overload induced retardation
International Journal of Fatigue, 2009Co-Authors: J R Mohanty, B B VermaAbstract:Almost all load bearing components usually experience variable amplitude loading (VAL) rather than constant amplitude loading (CAL) during their service lives. A single overload cycle introduced in a constant amplitude fatigue loading retards fatigue crack growth and increases residual fatigue life. Although many Models have been proposed on this subject, but life prediction under these complex situations is still under constant improvement. The present study aims at evaluating retardation in fatigue life due to application of a single tensile overload spike by adopting an Exponential Model. The proposed Model calculates not only parameters related with overload induced retardation in fatigue crack growth, but also residual life in case of 7020-T7 and 2024-T3 aluminum alloys with reasonable accuracy without integration of rate equation. The Model also covers stage-II and stage-III of post-overload period.
Qingchun Chen - One of the best experts on this subject based on the ideXlab platform.
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GLOBECOM - An Exponential Model for Evaluating Error Performance of Turbo Codes
2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:In this paper, an Exponential Model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed Exponential Model offers a simple but effective method to approximate the waterfall region performance of Turbo codes, which is generally intricate for analytical bounding techniques. By combining the proposed Exponential Model with the well known union bound estimate, the paper derives a combined performance Model to extend the performance estimate within moderate to high SNR region. Moreover, it is shown that, only the free distance term of the weight spectrum is not always enough for a reasonable estimate of the error floor region performance, especially when the free distance multiplicity is small. Numerical results are presented to validate the applicability of the proposed performance Model.
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An Exponential Model for Evaluating Error Performance of Turbo Codes
2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:In this paper, an Exponential Model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed Exponential Model offers a simple but effective method to approximate the waterfall region performance of Turbo codes, which is generally intricate for analytical bounding techniques. By combining the proposed Exponential Model with the well known union bound estimate, the paper derives a combined performance Model to extend the performance estimate within moderate to high SNR region. Moreover, it is shown that, only the free distance term of the weight spectrum is not always enough for a reasonable estimate of the error floor region performance, especially when the free distance multiplicity is small. Numerical results are presented to validate the applicability of the proposed performance Model.
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On the performance estimate for Turbo codes
2010 International Conference on Wireless Communications & Signal Processing (WCSP), 2010Co-Authors: Qingchun Chen, Jiaxiang Li, Vahid TarokhAbstract:Recently, the scaling law has been extended to approximate the waterfall performance for Turbo codes over the binary erasure channel. However, the waterfall approximation over other channels, such as the AWGN and Rayleigh fading channels, is still unknown for Turbo codes. In this paper, an Exponential Model was proposed to approximate the waterfall performance for Turbo codes. The relationship between the proposed Exponential Model and the scaling law will be highlighted at first. Our analysis unveils that the proposed Exponential Model could be regarded as a generalized scaling law Model, which makes it possible to achieve better performance estimate. The results in this paper explicitly shows that, the Exponential Model offers reasonable waterfall approximation for both word error probability and bit error probability for all packet sizes over a diverse channel, such as the binary erasure channel, the additive white Gaussian noise channel as well as the Rayleigh fading channel. The complete performance Model could be derived by combining the Exponential Model and the known union bound Model. Finally, some further discussions are presented to highlight the performance estimate problem for Turbo codes.
Zhongqiang Mu - One of the best experts on this subject based on the ideXlab platform.
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Remaining Useful Life Prediction for Lithium-Ion Batteries Based on Exponential Model and Particle Filter
IEEE Access, 2018Co-Authors: Lijun Zhang, Zhongqiang MuAbstract:As the secondary widely used battery, lithium-ion batteries (LIBs) have become the core component of the energy supply for most devices. Accurately predicting the current cycle time of LIBs is of great importance to ensure the reliability and safety of the equipment. In this paper, considering the nonlinear and non-Gaussian capacity degradation characteristics of LIBs, a remaining useful life (RUL) prediction method based on the Exponential Model and the particle filter is proposed. The cycle life test data of LIBs published by prognostics center of excellence in national aeronautics and space administration were Exponentially experiencing the rule of degradation. And then the extrapolation method was used to get the quantitative expression of the uncertainty of life expectancy of LIBs, i.e. the prediction mean and the probability distribution histogram. The prognostic horizon index and the new specific accuracy index were applied to evaluate the prediction performance. Moreover, the prediction error under different prediction starting points is given. Compared with other methods such as the auto-regressive integrated moving average Model, the fusion nonlinear degradation autoregressive Model and the regularized particle filter algorithm, the proposed algorithm has a better prediction performance. According to the accuracy index, the proposed prediction method has better prediction accuracy and convergence. The RUL prediction for LIBs can provide a better decision support for the maintenance and support systems to optimize maintenance strategies, and reduce maintenance costs.
James S Hyde - One of the best experts on this subject based on the ideXlab platform.
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characterization of continuously distributed cortical water diffusion rates with a stretched Exponential Model
Magnetic Resonance in Medicine, 2003Co-Authors: Kevin M Bennett, Kathleen M Schmainda, Raoqiong Bennett, Daniel B Rowe, Hanbing Lu, James S HydeAbstract:Experience with diffusion-weighted imaging (DWI) shows that signal attenuation is consistent with a multicompartmental theory of water diffusion in the brain. The source of this so-called nonExponential behavior is a topic of debate, because the cerebral cortex contains considerable microscopic heterogeneity and is therefore difficult to Model. To account for this heterogeneity and understand its implications for current Models of diffusion, a stretched-Exponential function was developed to describe diffusion-related signal decay as a continuous distribution of sources decaying at different rates, with no assumptions made about the number of participating sources. DWI experiments were performed using a spin-echo diffusionweighted pulse sequence with b-values of 500 ‐ 6500 s/mm 2 in six rats. Signal attenuation curves were fit to a stretched-Exponential function, and 20% of the voxels were better fit to the stretched-Exponential Model than to a biExponential Model, even though the latter Model had one more adjustable parameter. Based on the calculated intravoxel heterogeneity measure, the cerebral cortex contains considerable heterogeneity in diffusion. The use of a distributed diffusion coefficient (DDC) is suggested to measure mean intravoxel diffusion rates in the presence of such heterogeneity. Magn Reson Med 50: 727‐734, 2003. © 2003 Wiley-Liss, Inc. Two types of heterogeneity can be defined in MRI diffusion experiments: intravoxel and intervoxel. The goal of this work was to understand how intravoxel heterogeneity affects measurements of diffusion in the cerebral cortex using diffusion-weighted imaging (DWI). A stretched-Exponential Model was used to study the heterogeneity in DWI data.
