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In this paper, we propose a novel watermarking method in order to enhance the security in biometric voice/speech transmission systems basing on sub-sampling, discrete cosine transform (DCT) and adaptive watermark embedding. To improve imperceptibility, we use sub-sampling and adaptive embedding in DCT high energy coefficients. We employ a significant watermark represented in a biometric unique fingerprint. Introducing bits, only in high energy fraction, provides us with further agreeing element depicted by decreasing running time, both in embedding and extraction processes, which can help minimizing hardware consumption. Achieved results reveal the stability and flexibility of our proposed scheme and confirm its robustness against additive noise. In addition, we enhanced our previous published approaches and the expected limitations of our proposed model will appear in the hardware implementation where the attacks will be more considered. Another limitation will be the number of quantization bits used for high energy DCT coefficients. All these may affect the speaker secured identification and verification system. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel scheme for enhancing the security of speech information in communication systems. We build a hybridization of three approaches: Chaotic logistic and tent maps for generating an arbitrary vector by some primarily initiated values to be joined in the original speech signal, an integrated watermark image within the encrypted signal in order to verify, through decryption process, that the encrypted signal is authentic as well as does not suffer from eventual attacks, and the third approach is using an Arnold scrambling key (cat map) to spread signal samples by means of a secret key, then recuperate the original signal from samples which is not possible without this key. Obtained correlation value in the proposed scheme is closer to null which proves that original and encrypted signals are completely dissimilar. Moreover, we recovered the original speech without disturbing the quality. Numerical results of the Signal to Noise Ratio (SNR) and Correlation Coefficient (CC) reported below, and the comparison between the proposed approach to seven recently published works, also reported, reveal the superiority of the proposed scheme and validate our design to be considered amongst the best methods compared to other recently existing strong approaches. [ABSTRACT FROM AUTHOR]

In this paper, a new nature-inspired Artificial Ecosystem Optimization (AEO) methodology is presented for reducing the complexity of nonlinear PEMFC SR-12 500 W system. From the point view of this system, the hydrogen and oxygen pressures P H 2 = 60 atm , P O 2 = 30 atm as two inputs, the cell voltage and current as two outputs.By implementation of identification technique, the state space model of PEMFC stack is generated using nlarx modelling procedures where the obtained model is reduced their order by AEO method. The AEO mimics the energy flow behaviour between living organisms in a natural ecosystem, including production, consumption, and decomposition.This algorithm minimize the synergy ( H 2 , H ∞ ) norm of error between full PEMFC model and reduced order model. The obtained results are compared with the other optimization algorithms such as MRFO,SSA,ALO and GWO, and they are confirmed that the approximate model obtained by proposed algorithm has faster convergence and better approximation performance in synergy ( H 2 , H ∞ ) norm than those obtained by comparative algorithms in addition, it is proven to be accurate and reliable to investigate the PEMFC optimum global reduced order model which preserved the main behaviour of original PEMFC SR-12 500 W model. [ABSTRACT FROM AUTHOR]

In recent years, multimedia data is most used in the world such as image, audio, video and text. For reducing the great amount of generated data and for obtaining the better sensing performance, several researches have been focused on multimedia data fusion (MDF). The main objective of image fusion techniques in the visual sensor networks (VSNs) is to combine multiple images of the same scene captured by different cameras and with various focused regions into a single informative image. In this paper, we propose an efficient hybrid image fusion method which is suitable for VSNs based on the integer lifting wavelet transform (ILWT) and the discrete cosine transformer (DCT). The suggested fusion algorithm consists of two steps. Firstly, the approximate coefficients (low frequencies) generated by the ILWT are fused by selecting the variance as an activity level measure in the DCT domain. Secondly, the detail coefficients (high frequencies) are fused by taking the optimum weighted average based on the correlation between coefficients in ILWT domain. Due to the integer operations in ILWT domain, the proposed method overcomes the loss of information, computational complexity, time and energy consumption and memory space. Extensive experiments are performed to demonstrate the outperforming of the proposed method compared qualitatively and quantitatively with some literature image fusion techniques. [ABSTRACT FROM AUTHOR]

In this paper, a robust and blind speech watermarking technique is proposed using a combined scheme based on discrete cosine transform (DCT) and discrete wavelet transform (DWT) Algorithms within signal sub-sampling. To achieve good imperceptibility, hybridization is implemented against many attacks such as: re-quantization, cropping, echo, amplification and additive white Gaussian noise (AWGN). We profit from the advantages of correlation between two successive samples so that we used signal sub-sampling. Obtained results, compared successfully to recent researches, show the robustness of our proposed approach. [ABSTRACT FROM AUTHOR]

The aim of this work is the synthesis of a type-2 fuzzy logic PID controller for DC-DC boost converters. Performances of the proposed controller are evaluated and compared with those of type-1 fuzzy logic PID controller using the same structure and under similar operating conditions. Simulation results showed that the type-2 fuzzy logic PID controller has better performances than those of type-1 fuzzy logic PID controller. [ABSTRACT FROM AUTHOR]

This article aims to maximize the protective layers by the dynamic risk assessment within the facility Chemical/Petrochemical. This assessment is based on two necessary parts (Labeau et al. Reliab Eng Syst Saf 68:219-254, 2000): The first part concerns the deterministic analysis which is based on the modeling of a dynamic process to determine changes in process parameters, and the other part concerns the probabilistic analysis, which aims to evaluate accidents consequences by calculating the excess damage frequency during different scenarios. In this paper, we have taken, as an application case, accident scenarios at Bhopal (Malcolm Advances in Nuclear Science and Technology, 2002, 1-45) and by the exploitation of performances of thermo hydraulic 'GasTemp' and probabilistic 'SCAIS' codes, originally applied in nuclear industry, we could simulate the accidental sequences with the calculation of excess damage frequency. [ABSTRACT FROM AUTHOR]

This paper, explores the connection of a wind farm to the grid through high voltage direct current system on voltage source converter VSC-HVDC. 12 MW wind farm consisting of 6 individual 2 MW permanent magnet synchronous generators is presented. In this paper we proposed a new particle swarm optimization algorithm (PSO) based PI controller in order to optimize the gains of PI controller of VSC-HVDC link, which consequently improve the stability of the link after a strict faults. Different results are obtained to show the efficiency of the proposed PSO algorithm for the conception of optimal controller for a VSC-HVDC link connected to a wind farm. MATLAB/Similink simulations are provided to illustrate the performance of the proposed approach under serious perturbation as single AC fault and DC fault. [ABSTRACT FROM AUTHOR]

In this work, we try to design a DS-CDMA communication system model for the transmission of different types of images: binary, gray level and color. We adopted a transmission system of multiple users. During transmission of each image, we evaluated the noise and multiple access interference effects on the quality of DS-CDMA transmitted images which are inversely proportional to the length of the spreading sequence. Quality is assessed each time by the bit error rate (BER) estimation between received and original images. By increasing the signal to noise ratio to positive values, the BER tends to decrease, this results in a received image with fewer errors, thus without alteration which confirms Shannon equation. By using one user alone, the inter-user interference is canceled and the BER obtained is far lower than the BER obtained in presence of inter-user interferences. This can be resolved in hardware implementation using adequate filters. [ABSTRACT FROM AUTHOR]

The strategy of control for high-voltage direct current system on voltage-source converter VSC-HVDC is based on an important element which is PI controller. Because of its simple structure and strong robustness in a wide range of serving conditions, it has been used in the control system in the last few years. Therefore, it is important for the VSC-HVDC system permanent regime to choose proper PI parameters. The use of conventional techniques to find suitable PI parameters creates a number of challenges for the system operators, because it is a difficult process and time consuming. In this paper, a new swarm intelligence algorithm called bacterial foraging optimization is introduced to find the optimal parameters of the PI controller. This approach offers great flexibility for the permanent regime recovery and improves the stability of the VSC-HVDC link compared to conventional techniques. The obtained results are presented to show the effectiveness of the proposed swarm implementation for optimal controller design for VSC-HVDC transmission. MATLAB/Similink simulations are provided to demonstrate the performance of the proposed approach. [ABSTRACT FROM AUTHOR]