Papers by Djeugoue Hermann
Multimedia Tools and Applications, Apr 26, 2022
This paper presents a piece-wise linear cat map (PWLCM) obtained by perturbing the conventional q... more This paper presents a piece-wise linear cat map (PWLCM) obtained by perturbing the conventional quantized Arnold cat map (QACM) with a nonlinear term. The effect of the nonlinear term on the dynamics of the QACM is investigated. We show that the eigenvalues, hence the Lyapunov exponents of the PWLCM depend on the initial conditions, which is not the case for the QACM. As a result, the proposed PWLCM is a generalized form of the QACM, whose the period exponentially increases with respect to the precision, thus taking as value 1.09 × 10 513 for only 10-bit precision; while that of the corresponding QACM is only 768. The nonlinear term increases the sensitivity of the system to the initial conditions, which contributes to increase its period, hence to enhance its complexity. An electronic implementation of both the QACM and the PWLCM in the case of 4-bit precision using Multisim is presented. The proposed architecture of both the QACM and the PWLCM are implemented using Verilog and prototyped on the Zynq 7020 FPGA board. For 4-bit precision, the FPGA implementation performs 1.072 Gbps throughput at 134 MHz maximum frequency. We verified that experimental and simulation behaviors of the proposed system perfectly match, thus confirming the effectiveness of the proposed electronic circuit for exhibiting the expected dynamics in real-time.
Multimedia Tools and Applications, 2022
This paper presents a piece-wise linear cat map (PWLCM) obtained by perturbing the conventional q... more This paper presents a piece-wise linear cat map (PWLCM) obtained by perturbing the conventional quantized Arnold cat map (QACM) with a nonlinear term. The effect of the nonlinear term on the dynamics of the QACM is investigated. We show that the eigenvalues, hence the Lyapunov exponents of the PWLCM depend on the initial conditions, which is not the case for the QACM. As a result, the proposed PWLCM is a generalized form of the QACM, whose the period exponentially increases with respect to the precision, thus taking as value 1.09 × 10 513 for only 10-bit precision; while that of the corresponding QACM is only 768. The nonlinear term increases the sensitivity of the system to the initial conditions, which contributes to increase its period, hence to enhance its complexity. An electronic implementation of both the QACM and the PWLCM in the case of 4-bit precision using Multisim is presented. The proposed architecture of both the QACM and the PWLCM are implemented using Verilog and prototyped on the Zynq 7020 FPGA board. For 4-bit precision, the FPGA implementation performs 1.072 Gbps throughput at 134 MHz maximum frequency. We verified that experimental and simulation behaviors of the proposed system perfectly match, thus confirming the effectiveness of the proposed electronic circuit for exhibiting the expected dynamics in real-time.
Electrical and Computer …, 2008
This paper presents an experimental evaluation of oversampled, modulated filter banks for joint s... more This paper presents an experimental evaluation of oversampled, modulated filter banks for joint subband audio processing and coding applications. Joint subband processing and coding may be useful in some wireless audio devices such as advanced wireless digital hearing aids. We examine the use of oversampled GDFT and cosine modulated filter banks and propose using single sideband (SSB) real-valued filter banks as a compromise which is ideal for this application. The SSB filter bank provides real-valued signals for coding which are free from any aliasing cancellation constraints and hence are also suitable for non-uniform subband processing such as subband gain adjustment. We support this conclusion with an experimental analysis of various filter bank designs for subband gain adjustment and subband audio coding.
Djeugoue, 2019
L’algèbre modulaire est très utilisée dans la synthèse des générateurs de nombre pseudo aléatoire... more L’algèbre modulaire est très utilisée dans la synthèse des générateurs de nombre pseudo aléatoire et dans la cryptographie des données. Cependant les méthodes permettant d’obtenir des composants électroniques discrets permettant de réaliser les opérations d’algèbre modulaire restent assez rares dans la littérature. Dans l’optique d’optimiser la conception des RNG (Random Number Generator), nous avons entrepris dans ce travail de concevoir des circuits électroniques capable de réaliser l’opération d’arithmétique modulaire pour des entiers positifs et dont les modulos sont des valeurs fixe. Nous avons pris comme exemple le modulo 5 et 11 (calculateur modulo 5 et 11). L’approche présentée dans ce travail possède un intérêt particulier en ce sens qu’elle n’utilise que l’addition binaire et permet de résoudre le problème de rapidité présent dans les méthodes de calcul algorithmiques.
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Papers by Djeugoue Hermann