In this paper, we investigate the IEEE 802.11p based Vehicular Ad-hoc Network transition between ... more In this paper, we investigate the IEEE 802.11p based Vehicular Ad-hoc Network transition between non-saturation and saturation regimes with mobile nodes. We combine vehicular traffic theory, queuing model and Markov chain to evaluate the performance of the network under spatial or networking saturation for mutiple data classes over control and service channels with different transmission rates depending on the vehicle's distance from the roadside unit (RSU). Our results show that the vehicle density growth can result in saturation of wireless medium around the RSU, further resulting in buffer overflows at on board units.
ABSTRACT IEEE 802.11p is a new communication standard for wireless access in vehicular environmen... more ABSTRACT IEEE 802.11p is a new communication standard for wireless access in vehicular environment (WAVE), intended to support road safety messages, electronic toll collection, infotainment services, and other as well as a number of other intelligent transportation systems (ITS) applications. In this paper, we focus on the impact of the dwelling time on the control channel (CCH) vs. that on the SCH (i.e., the duty cycle) on the performance of video communication on the service channel (SCH), using a novel analytical model. We show that a range of duty cycles allows for satisfactory performance of video traffic on SCH as well as timely delivery of safety messages on CCH.
In this paper, a novel robust watermarking technique based on discrete cosine transform using gen... more In this paper, a novel robust watermarking technique based on discrete cosine transform using genetic algorithm (GA) is presented. To obtain highest possible robustness without losing transparency, GA is used for adjustment of mid-band coefficients. Significant improvements in robustness under attacks and also in transparency are obtained from experimental results.
In this paper, a novel fragile watermarking scheme based on discrete cosine transform (DCT) using... more In this paper, a novel fragile watermarking scheme based on discrete cosine transform (DCT) using particle swarm optimization (PSO) algorithm is presented. Embedding watermarks in frequency domain can usually be achieved by modifying the least significant bits (LSBs) of the transformation coefficients. After embedding process is completed, a number of rounding errors appear due to conversion of real numbers into integers in the process of transformation of image from frequency domain to spatial domain. A population based stochastic optimization technique (PSO) is proposed to correct these rounding errors. Simulation results show the feasibility of employing PSO for watermarking and the accuracy of this novel method.
In this paper, a novel fragile watermarking method based on clonal selection algorithm (CSA), CLO... more In this paper, a novel fragile watermarking method based on clonal selection algorithm (CSA), CLONALG, is presented. In Discrete Cosine Transform (DCT) based fragile watermarking techniques, there occurs some degree of rounding errors because of the conversion of real numbers into integers in the process of transformation of image from frequency domain to spatial domain. In this paper, the rounding errors caused by this transformation process are corrected by using CLONALG. Simulation results show that extracted watermark is obtained exactly the same as embedded watermark and optimum watermarked image transparency is achieved. In addition, the performance comparison of CLONALG and genetic algorithm (GA) based methods is realized.
Abstract Several watermarking schemes have been proposed with the purpose of copyright protection... more Abstract Several watermarking schemes have been proposed with the purpose of copyright protection and access control for multimedia objects. In this paper, an optimal discrete wavelet transform-singular value decomposition (DWT-SVD) based image watermarking ...
In this paper, we investigate the IEEE 802.11p based Vehicular Ad-hoc Network transition between ... more In this paper, we investigate the IEEE 802.11p based Vehicular Ad-hoc Network transition between non-saturation and saturation regimes with mobile nodes. We combine vehicular traffic theory, queuing model and Markov chain to evaluate the performance of the network under spatial or networking saturation for mutiple data classes over control and service channels with different transmission rates depending on the vehicle's distance from the roadside unit (RSU). Our results show that the vehicle density growth can result in saturation of wireless medium around the RSU, further resulting in buffer overflows at on board units.
ABSTRACT IEEE 802.11p is a new communication standard for wireless access in vehicular environmen... more ABSTRACT IEEE 802.11p is a new communication standard for wireless access in vehicular environment (WAVE), intended to support road safety messages, electronic toll collection, infotainment services, and other as well as a number of other intelligent transportation systems (ITS) applications. In this paper, we focus on the impact of the dwelling time on the control channel (CCH) vs. that on the SCH (i.e., the duty cycle) on the performance of video communication on the service channel (SCH), using a novel analytical model. We show that a range of duty cycles allows for satisfactory performance of video traffic on SCH as well as timely delivery of safety messages on CCH.
In this paper, a novel robust watermarking technique based on discrete cosine transform using gen... more In this paper, a novel robust watermarking technique based on discrete cosine transform using genetic algorithm (GA) is presented. To obtain highest possible robustness without losing transparency, GA is used for adjustment of mid-band coefficients. Significant improvements in robustness under attacks and also in transparency are obtained from experimental results.
In this paper, a novel fragile watermarking scheme based on discrete cosine transform (DCT) using... more In this paper, a novel fragile watermarking scheme based on discrete cosine transform (DCT) using particle swarm optimization (PSO) algorithm is presented. Embedding watermarks in frequency domain can usually be achieved by modifying the least significant bits (LSBs) of the transformation coefficients. After embedding process is completed, a number of rounding errors appear due to conversion of real numbers into integers in the process of transformation of image from frequency domain to spatial domain. A population based stochastic optimization technique (PSO) is proposed to correct these rounding errors. Simulation results show the feasibility of employing PSO for watermarking and the accuracy of this novel method.
In this paper, a novel fragile watermarking method based on clonal selection algorithm (CSA), CLO... more In this paper, a novel fragile watermarking method based on clonal selection algorithm (CSA), CLONALG, is presented. In Discrete Cosine Transform (DCT) based fragile watermarking techniques, there occurs some degree of rounding errors because of the conversion of real numbers into integers in the process of transformation of image from frequency domain to spatial domain. In this paper, the rounding errors caused by this transformation process are corrected by using CLONALG. Simulation results show that extracted watermark is obtained exactly the same as embedded watermark and optimum watermarked image transparency is achieved. In addition, the performance comparison of CLONALG and genetic algorithm (GA) based methods is realized.
Abstract Several watermarking schemes have been proposed with the purpose of copyright protection... more Abstract Several watermarking schemes have been proposed with the purpose of copyright protection and access control for multimedia objects. In this paper, an optimal discrete wavelet transform-singular value decomposition (DWT-SVD) based image watermarking ...
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