IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
Subharmonic generation from ultrasound contrast agents depends on the spectral and temporal prope... more Subharmonic generation from ultrasound contrast agents depends on the spectral and temporal properties of the excitation signal. The subharmonic response can be improved by using wideband and long duration signals. However, for sinusoidal tone-burst excitation the effective bandwidth of the signal is inversely proportional with the signal duration. Linear frequency modulated (LFM) and nonlinear frequency modulated (NLFM) chirp excitations allow independent control over the signal bandwidth and duration, therefore in this study LFM and NLFM signals were used for the insonation of microbubble populations. The amplitude modulation of the excitation waveform was achieved by applying different window functions. A customized window was designed for the NLFM chirp excitation by focusing on reducing the spectral leakage at the subharmonic frequency and increasing the subharmonic generation from microbubbles.
2010 IEEE International Conference on Wireless Information Technology and Systems
In this work, we propose the κ-μ/gamma composite distribution. Specifically, we start by formulat... more In this work, we propose the κ-μ/gamma composite distribution. Specifically, we start by formulating the κ-μ/gamma and consequently derive a closed-form expression for its envelope probability density function (pdf). The κ-μ distribution includes as special cases the Nakagami-n (Rice), Nakagami-m, Rayleigh and one-sided Gaussian distributions.
2010 IEEE International Conference on Wireless Information Technology and Systems, 2010
Page 1. The η-µ/gamma composite fading model Paschalis C. Sofotasios and Steven Freear School of ... more Page 1. The η-µ/gamma composite fading model Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] Introduction ...
2010 IEEE International Conference on Wireless Information Technology and Systems, 2010
Page 1. Novel Expressions for the One and Two Dimensional Gaussian Q-functions Paschalis C. Sofot... more Page 1. Novel Expressions for the One and Two Dimensional Gaussian Q-functions Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] ...
2010 IEEE International Ultrasonics Symposium, 2010
The search for an increase in medical imaging frame rate has been on-going for decades. A number ... more The search for an increase in medical imaging frame rate has been on-going for decades. A number of coding techniques may be applied based on simultaneous transmission from multiple sub-apertures. Linear frequency modulated (LFM) signals or chirps is a coding technique with the ability to enhance the SNR but the coding diversity is limited, for example up chirp and down
Page 1. Novel Expressions for the Marcum and One Dimensional Q-functions Paschalis C. Sofotasios ... more Page 1. Novel Expressions for the Marcum and One Dimensional Q-functions Paschalis C. Sofotasios 1 , Steven Freear 2 School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK 1 [email protected] 2 [email protected] ...
This work is devoted in the derivation of novel upper and lower bounds for the Rice Ie-function. ... more This work is devoted in the derivation of novel upper and lower bounds for the Rice Ie-function. These bounds are expressed in closed-form and are shown to be quite tight. This is particularly evident by the fact that for a certain range of parameter values, the derived lower bound virtually behaves as a remarkably accurate approximation. As a result, the
Page 1. A Novel Representation for the Nuttall Q-function Paschalis C. Sofotasios and Steven Free... more Page 1. A Novel Representation for the Nuttall Q-function Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] Introduction ...
2011 IEEE Wireless Communications and Networking Conference, 2011
Page 1. The κ-μ Extreme/Gamma Distribution: A Physical Composite Fading Model Paschalis C. Sofota... more Page 1. The κ-μ Extreme/Gamma Distribution: A Physical Composite Fading Model Paschalis C. Sofotasios School of Electronic and Electrical Engineering University of Leeds, UK e-mail: [email protected] Steven Freear ...
This paper presents the formulation and derivation of the α-κ-µ Extreme distribution. This is a f... more This paper presents the formulation and derivation of the α-κ-µ Extreme distribution. This is a fading model that is distinct for its capability to account for the characterization of mobile radio propagation under non-linear severe fading conditions. This capability results from the remarkable flexibility offered by its parameters. Closed-form expressions for the envelope and power probability density and distribution functions
This work is devoted to the formulation and derivation of the α — κ — μ/gamma distribution which ... more This work is devoted to the formulation and derivation of the α — κ — μ/gamma distribution which corresponds to a physical fading model. The proposed distribution is composite and is constituted by the α — κ — μ non-linear generalized multi-path model and the gamma shadowing model. It also constitute the basis for deriving the α — κ —
Page 1. Simple and Accurate Approximations for the Two Dimensional Gaussian Q-function Paschalis ... more Page 1. Simple and Accurate Approximations for the Two Dimensional Gaussian Q-function Paschalis C. Sofotasios School of Electronic and Electrical Engineering University of Leeds, UK Email: [email protected] Steven ...
This work is devoted to the formulation and derivation of the κ-μ/gamma distribution which corres... more This work is devoted to the formulation and derivation of the κ-μ/gamma distribution which corresponds to A physical fading model. This distribution is composite and is based on the well known κ-μ generalized multipath model and the gamma shadowing model. A special case of the derived model constitutes the κ-μ Extreme/gamma model which accounts for severe multipath and shadowing effects.
This work is devoted to the formulation and derivation of the η — µ/gamma and λ — µ/gamma distrib... more This work is devoted to the formulation and derivation of the η — µ/gamma and λ — µ/gamma distributions which correspond to physical fading models. These distributions are composite and are based on the η — µ and λ — µ generalized multipath models, respectively, and the gamma shadowing model. Novel analytic expressions are derived for the corresponding envelope probability
This paper provides novel analytic expressions for the incomplete Toronto function, TB(m, n, r), ... more This paper provides novel analytic expressions for the incomplete Toronto function, TB(m, n, r), and the incomplete Lipschitz-Hankel Integrals of the modified Bessel function of the first kind, Ieμ, n(a, z). These expressions are expressed in closed-form and are valid for the case that m ≥ n and n being an odd multiple of 1/2, i.e. n ± 0.5 Є
This paper presents novel analytic expressions for the Rice Ie-function, Ie(k, x), and the incomp... more This paper presents novel analytic expressions for the Rice Ie-function, Ie(k, x), and the incomplete Lipschitz-Hankel Integrals (ILHIs) of the modified Bessel function of the first kind, Iem, n(a, z). Firstly, an exact infinite series and an accurate polynomial approximation are derived for the Ie(k, x) function which are valid for all values of k. Secondly, an exact closed-form expression
The VLSI implementation of SISO-MAP decoders used for traditional iterative turbo coding has been... more The VLSI implementation of SISO-MAP decoders used for traditional iterative turbo coding has been investigated in the literature. In this paper, a complete architectural model of a space-time turbo code receiver that includes elementary decoders is presented. These architectures are based on newly proposed building blocks such as a recursive add-compare-select-offset (ACSO) unit, A-, B-, Γ-, and LLR output calculation modules. Measurements of complexity and decoding delay of several sliding-windowtechnique-based MAP decoder architectures and a proposed parameter set lead to defining equations and comparison between those architectures.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
Subharmonic generation from ultrasound contrast agents depends on the spectral and temporal prope... more Subharmonic generation from ultrasound contrast agents depends on the spectral and temporal properties of the excitation signal. The subharmonic response can be improved by using wideband and long duration signals. However, for sinusoidal tone-burst excitation the effective bandwidth of the signal is inversely proportional with the signal duration. Linear frequency modulated (LFM) and nonlinear frequency modulated (NLFM) chirp excitations allow independent control over the signal bandwidth and duration, therefore in this study LFM and NLFM signals were used for the insonation of microbubble populations. The amplitude modulation of the excitation waveform was achieved by applying different window functions. A customized window was designed for the NLFM chirp excitation by focusing on reducing the spectral leakage at the subharmonic frequency and increasing the subharmonic generation from microbubbles.
2010 IEEE International Conference on Wireless Information Technology and Systems
In this work, we propose the κ-μ/gamma composite distribution. Specifically, we start by formulat... more In this work, we propose the κ-μ/gamma composite distribution. Specifically, we start by formulating the κ-μ/gamma and consequently derive a closed-form expression for its envelope probability density function (pdf). The κ-μ distribution includes as special cases the Nakagami-n (Rice), Nakagami-m, Rayleigh and one-sided Gaussian distributions.
2010 IEEE International Conference on Wireless Information Technology and Systems, 2010
Page 1. The η-µ/gamma composite fading model Paschalis C. Sofotasios and Steven Freear School of ... more Page 1. The η-µ/gamma composite fading model Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] Introduction ...
2010 IEEE International Conference on Wireless Information Technology and Systems, 2010
Page 1. Novel Expressions for the One and Two Dimensional Gaussian Q-functions Paschalis C. Sofot... more Page 1. Novel Expressions for the One and Two Dimensional Gaussian Q-functions Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] ...
2010 IEEE International Ultrasonics Symposium, 2010
The search for an increase in medical imaging frame rate has been on-going for decades. A number ... more The search for an increase in medical imaging frame rate has been on-going for decades. A number of coding techniques may be applied based on simultaneous transmission from multiple sub-apertures. Linear frequency modulated (LFM) signals or chirps is a coding technique with the ability to enhance the SNR but the coding diversity is limited, for example up chirp and down
Page 1. Novel Expressions for the Marcum and One Dimensional Q-functions Paschalis C. Sofotasios ... more Page 1. Novel Expressions for the Marcum and One Dimensional Q-functions Paschalis C. Sofotasios 1 , Steven Freear 2 School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK 1 [email protected] 2 [email protected] ...
This work is devoted in the derivation of novel upper and lower bounds for the Rice Ie-function. ... more This work is devoted in the derivation of novel upper and lower bounds for the Rice Ie-function. These bounds are expressed in closed-form and are shown to be quite tight. This is particularly evident by the fact that for a certain range of parameter values, the derived lower bound virtually behaves as a remarkably accurate approximation. As a result, the
Page 1. A Novel Representation for the Nuttall Q-function Paschalis C. Sofotasios and Steven Free... more Page 1. A Novel Representation for the Nuttall Q-function Paschalis C. Sofotasios and Steven Freear School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, Leeds, UK E-mail: [email protected], [email protected] Introduction ...
2011 IEEE Wireless Communications and Networking Conference, 2011
Page 1. The κ-μ Extreme/Gamma Distribution: A Physical Composite Fading Model Paschalis C. Sofota... more Page 1. The κ-μ Extreme/Gamma Distribution: A Physical Composite Fading Model Paschalis C. Sofotasios School of Electronic and Electrical Engineering University of Leeds, UK e-mail: [email protected] Steven Freear ...
This paper presents the formulation and derivation of the α-κ-µ Extreme distribution. This is a f... more This paper presents the formulation and derivation of the α-κ-µ Extreme distribution. This is a fading model that is distinct for its capability to account for the characterization of mobile radio propagation under non-linear severe fading conditions. This capability results from the remarkable flexibility offered by its parameters. Closed-form expressions for the envelope and power probability density and distribution functions
This work is devoted to the formulation and derivation of the α — κ — μ/gamma distribution which ... more This work is devoted to the formulation and derivation of the α — κ — μ/gamma distribution which corresponds to a physical fading model. The proposed distribution is composite and is constituted by the α — κ — μ non-linear generalized multi-path model and the gamma shadowing model. It also constitute the basis for deriving the α — κ —
Page 1. Simple and Accurate Approximations for the Two Dimensional Gaussian Q-function Paschalis ... more Page 1. Simple and Accurate Approximations for the Two Dimensional Gaussian Q-function Paschalis C. Sofotasios School of Electronic and Electrical Engineering University of Leeds, UK Email: [email protected] Steven ...
This work is devoted to the formulation and derivation of the κ-μ/gamma distribution which corres... more This work is devoted to the formulation and derivation of the κ-μ/gamma distribution which corresponds to A physical fading model. This distribution is composite and is based on the well known κ-μ generalized multipath model and the gamma shadowing model. A special case of the derived model constitutes the κ-μ Extreme/gamma model which accounts for severe multipath and shadowing effects.
This work is devoted to the formulation and derivation of the η — µ/gamma and λ — µ/gamma distrib... more This work is devoted to the formulation and derivation of the η — µ/gamma and λ — µ/gamma distributions which correspond to physical fading models. These distributions are composite and are based on the η — µ and λ — µ generalized multipath models, respectively, and the gamma shadowing model. Novel analytic expressions are derived for the corresponding envelope probability
This paper provides novel analytic expressions for the incomplete Toronto function, TB(m, n, r), ... more This paper provides novel analytic expressions for the incomplete Toronto function, TB(m, n, r), and the incomplete Lipschitz-Hankel Integrals of the modified Bessel function of the first kind, Ieμ, n(a, z). These expressions are expressed in closed-form and are valid for the case that m ≥ n and n being an odd multiple of 1/2, i.e. n ± 0.5 Є
This paper presents novel analytic expressions for the Rice Ie-function, Ie(k, x), and the incomp... more This paper presents novel analytic expressions for the Rice Ie-function, Ie(k, x), and the incomplete Lipschitz-Hankel Integrals (ILHIs) of the modified Bessel function of the first kind, Iem, n(a, z). Firstly, an exact infinite series and an accurate polynomial approximation are derived for the Ie(k, x) function which are valid for all values of k. Secondly, an exact closed-form expression
The VLSI implementation of SISO-MAP decoders used for traditional iterative turbo coding has been... more The VLSI implementation of SISO-MAP decoders used for traditional iterative turbo coding has been investigated in the literature. In this paper, a complete architectural model of a space-time turbo code receiver that includes elementary decoders is presented. These architectures are based on newly proposed building blocks such as a recursive add-compare-select-offset (ACSO) unit, A-, B-, Γ-, and LLR output calculation modules. Measurements of complexity and decoding delay of several sliding-windowtechnique-based MAP decoder architectures and a proposed parameter set lead to defining equations and comparison between those architectures.
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