Nonlinear output feedback control of V2G single‐phase on‐board BEV charger

In this work, we consider the problem of controlling a single‐phase on‐board battery electric vehicle (BEV) charger with vehicle‐to‐grid (V2G) technology. The BEV charger consists of a bidirectional ac‐dc power converter connected to the single‐phase power grid, followed by a bidirectional dc‐dc power converter interfacing an EV battery pack. The main control objectives are fourfold: (i) Unitary Power Factor (UPF) in grid‐side; (ii) tight dc‐bus voltage regulation; (iii) safety battery charge and battery discharge during the grid‐to‐vehicle (G2V) mode and V2G mode, respectively; and (iv) asymptotic stability of the closed loop system. After an accurate system modelling, a nonlinear controller is designed using a backstepping design technique. The point is that the battery inner voltage is not accessible to measurement. Therefore, a nonlinear observer is invoked in order to estimate all non‐measured variables making the solution cheaper and noiseless. It is shown using a formal analysis and numerical simulations, that the proposed output feedback controller (combining a nonlinear controller and a nonlinear observer) meets all control objectives.     

High payload multi-channel dual audio watermarking algorithm based on discrete wavelet transform and singular value decomposition

Digital watermarking technology is concerned with solving the problem of copyright protection, data authentication, content identification, distribution, and duplication of the digital media due to the great developments in computers and Internet technology. Recently, protection of digital audio signals has attracted the attention of researchers. This paper proposes a new audio watermarking scheme based on discrete wavelet transform (DWT), singular value decomposition (SVD), and quantization index modulation (QIM) with a synchronization code embedded with two encrypted watermark images or logos inserted into a stereo audio signal. In this algorithm, the original audio signal is split into blocks, and each block is decomposed with a two-level DWT, and then the approximate low-frequency sub-band coefficients are decomposed by SVD transform to obtain a diagonal matrix. The prepared watermarking and synchronization code bit stream is embedded into the diagonal matrix using QIM. After that, we perform inverse singular value decomposition (ISVD) and inverse discrete wavelet transform (IDWT) to obtain the watermarked audio signal. The watermark can be blindly extracted without knowledge of the original audio signal. Experimental results show that the transparency and imperceptibility of the proposed algorithm is satisfied, and that robustness is strong against popular audio signal processing attacks. High watermarking payload is achieved through the proposed scheme.     

An optimized parallel order scheme of the deblocking filtering process for enhancing the performance of the HEVC standard using GPUs

In HEVC, deblocking filtering (DF) is responsible for about 20% of the time consumed to perform video compression. In a typical parallel DF scheme, a set of horizontal and vertical edges are processed using deblocking filters. In conventional parallel DF schemes, deblocking filters could be applied to the same edges more than once. Moreover, some edges are assigned to cores to be filtered even though those edges are not designated to be filtered. Accordingly, the used parallel hardware architecture requires more on-chip memory modules. Those challenges negatively affect HEVC performance resulting in an increase in computational complexity. In this paper, an optimized parallel DF scheme is proposed for HEVC using graphical processing units (GPUs). The proposed scheme outperforms competing ones in terms of reducing the decoding time of all frames of video sequences by average speed-up factors of 2.83 and 2.45 using the all-intra and low-delay video coding configuration modes, respectively. The proposal does not change the rate-distortion between the decoded video sequences and their original sequences.     

Early Failure of Waste Heat Boiler and Redesign to Overcome Premature Failure

Analyzing the premature failures that occur during boiler operation is an essential engineering process to keep power plant working smoothly. This article describes the general procedures, techniques and precautions employed in the investigation of boilers that fail in service. It also discusses redesign of the boiler to overcome premature failure. Increasing the maximum allowable load of boiler can be effective to overcome that problem. The paper suggests solutions that, if implemented, can reduce the incidence of boiler unscheduled outages.     

Evaluation of a portable in-house greywater treatment system for potential water-reuse in urban areas

This study aims at improving greywater reuse potential. An advanced physical filtration system named as GAC-MI-ME was developed to attain multi-grade effluents for versatile reuse of greywater. It consists of a matrix of treatment trains including coarse filtration, microfiltration, activated carbon, ultrafiltration, ultraviolet, and reverse osmosis. A preliminary set of experiments were conducted to characterize the greywater originating from shower, washbasin, and laundry. The samples were subsequently treated through GAC-MI-ME system. It was observed that the activated carbon along with microfiltration and coarse filtration played vital roles as pre-filtration for ultrafiltration and reverse osmosis. The contaminant load distributions of GAC-MI-ME system were observed with an average of 90.4% turbidity and 53.2% of biochemical oxidation demand (BOD₅₎ as the pre-filtration, whereas the effluents at ultrafiltration and reverse osmosis showed unrestricted water reuse possibilities. The GAC-MI-ME system can be envisioned as advancement to the conventionally applied greywater treatments.     

Environmental impacts of single and successive breakwaters along the Mediterranean coastline at Radès–Ezzahra, NE Tunisia

The coastline between Radès and Ezzahra, NE Tunisia, suffered from erosion during a strong storm in 1981. As a consequence, between 1985 and 1988, a single breakwater was constructed in Radès and two successive breakwaters in Ezzahra. The paper reports a study of the effectiveness of these structures and considers the other factors which influence the accretion/erosion of the shoreline.