Digital processing of speech signals

Digital Coding of Waveforms

Electrifying transportation is a promising approach to alleviate the climate change issue. The adoption of electric vehicle into market has introduced significant impacts on various fields, especially the power grid. Various policies have been implemented to foster the electric vehicle deployment and the increasing trend of electric vehicle adoption in the recent years has been satisfying. The continual development of electric vehicle power train, battery and charger technologies have further improved the electric vehicle technologies for wider uptake. Despite the environmental and economical benefits, electric vehicles charging introduce negative impacts on the existing network operation. Appropriate charging management strategies can be implemented to cater for this issue. Furthermore, electric vehicle integration in the smart grid can bring many potential opportunities, especially from the perspective of vehicle-to-grid technology and as the solution for the renewable energy intermittency issue. This paper reviews the latest development in electric vehicle technologies, impacts of electric vehicle roll out and opportunities brought by electric vehicle deployment.

A review on the state-of-the-art technologies of electric vehicle, its impacts and prospects

Video processing systems such as HEVC requiring low energy consumption needed for the multimedia market has lead to extensive development in fast algorithms for the efficient approximation of 2-D DCT transforms. The DCT is employed in a multitude of compression standards due to its remarkable energy compaction properties. Multiplier-free approximate DCT transforms have been proposed that offer superior compression performance at very low circuit complexity. Such approximations can be realized in digital VLSI hardware using additions and subtractions only, leading to significant reductions in chip area and power consumption compared to conventional DCTs and integer transforms. In this paper, we introduce a novel 8-point DCT approximation that requires only 14 addition operations and no multiplications. The proposed transform possesses low computational complexity and is compared to state-of-the-art DCT approximations in terms of both algorithm complexity and peak signal-to-noise ratio. The proposed DCT approximation is a candidate for reconfigurable video standards such as HEVC. The proposed transform and several other DCT approximations are mapped to systolic-array digital architectures and physically realized as digital prototype circuits using FPGA technology and mapped to 45 nm CMOS technology.

Improved 8-point Approximate DCT for Image and Video Compression Requiring Only 14 Additions

The discrete cosine transform (DCT), introduced by Ahmed, Natarajan and Rao, has been used in many applications of digital signal processing, data compression and information hiding. There are four types of the discrete cosine transform. In simulating the discrete cosine transform, we propose a generalized discrete cosine transform with three parameters, and prove its orthogonality for some new cases. A new type of discrete cosine transform is proposed and its orthogonality is proved. Finally, we propose a generalized discrete W transform with three parameters, and prove its orthogonality for some new cases. Keywords: Discrete Fourier transform, discrete sine transform, discrete cosine transform, discrete W transform Nigerian Journal of Technological Research , vol7(1) 2012

On discrete cosine transform

With the development of electric vehicles and smart grid, vehicle-to-grid (V2G) will become an inevitable. This paper presented a smart meter applied to vehicle-to-grid. The smart meter is introduced according to the function and characteristic of energy measurement chip ADE7758 and the microprocessor chip S3C2440 is also used in the circuit system. According to the difference of phase angle between the current and the voltage waveform in the electric grid, the energy consuming direction can be judged. Therefore, the consumption energy or export energy of an electric vehicle can be calculated. With the smart meter, bidirectional communication and remote control can be achieved between electric vehicle and the grid. Besides the special functions above, the smart meter is able to measure voltage and current, active and reactive power, and other electric parameters.

Design and implementation of the smart meter in vehicle-to-grid

Harmonics in power system are harmful to power network. In order to analyze power system harmonic more accurately, a new harmonic analysis algorithm based on interpolating windowed FFT and wavelet transform is proposed. This approach overcomes the shortcoming of FFT having frequency domain localization ability, but without time-domain localization ability. In this paper, the original signal is decomposed into the high-frequency component and the low-frequency component by the discrete wavelet transform. The low-frequency part is analyzed by interpolating windowed FFT algorithm to get the amplitude and phase of every steady harmonic. Simulation experiments are conducted with Matlab. The experimental results show that this method can not only analyze the steady-state harmonic accurately, but also inspect non-steady harmonics effectively.

Power system harmonic analysis based on windowed FFT and wavelet transform

In this paper, the properties of the all phase biorthogonal transform (APBT) matrix are deduced based on the concepts of all phase biorthogonal transform. A novel algorithm is presented to compress color image using the all phase Walsh biorthogonal transform (APWBT), the all phase discrete cosine biorthogonal transform (APDCBT) and the all phase inverse discrete cosine biorthogona transform (APIDCBT), instead of the conventional discrete cosine transform (DCT). Compared with the DCT-based JPEG image compression algorithm, we use the all phase biorthogonal transform matrix to reduce interpixel redundancy and propose uniform quantization to the APBT coefficients aiming at reducing the computation complexity. Experimental results show that the CPSNR of the proposed algorithm performs close to the DCT and outperforms the DCT at low bit rates especially.

http://or.nsfc.gov.cn/bitstream/00001903-5/333077/1/1000006982369.pdf

Properties of all phase biorthogonal transform matrix and its application in color image compression

—In this paper shape adaptive all phase biorthogonal transform (SA-APBT) for coding arbitrarily shaped image segments is proposed. The proposed transform can be used in region-based image compression instead of the shape adaptive discrete cosine transform (SA-DCT). Region-based image coding method is made up of three procedures: image segmentation, contour coding and texture coding. An image is divided into region-of-interest (ROI) and background area by image segmentation. Both areas are encoded and decoded independently. Experimental results on test images show that compared with SA-DCT at the same bit rates, the PSNRs and visual effects of reconstructed images based on SA-APBT are comparable to the one based on SA-DCT especially at low bit rates. And the SA-APBT transform coefficients are quantized uniformly, while the SA-DCT transform coefficients are quantized according to different quantization steps in the quantization table. So the quantization based on SA-APBT is simpler and computational complexity is reduced.

/pdf/shape-adaptive-all-phase-biorthogonal-transform-and-its-45mwbq0gug.pdf

Shape Adaptive All Phase Biorthogonal Transform and Its Application in Image Coding

—To improve the coding performance in JPEG image compression and reduce the computational complexity, this paper proposes a new transform called All Phase Inverse Discrete Sine Biorthogonal Transform (APIDSBT) based on the All Phase Biorthogonal Transform (APBT) and Inverse Discrete Sine Transform (IDST). Similar to Discrete Sine Transform (DST) matrix and Discrete Cosine Transform (DCT) matrix, it can be used in image compression which transforms the image from spatial domain to frequency domain. Compared with other transforms in JPEG-like image compression algorithm, the Peak Signal-to-Noise Ratio (PSNR) and subjective effects of the reconstructed images using the proposed transform and image coding scheme are better at the same bit rates, especially at low bit rates. The advantage is that the quantization process is simpler and the computational complexity is lower.

Baochen Jiang

Papers

Design and implementation of the smart meter in vehicle-to-grid

Power system harmonic analysis based on windowed FFT and wavelet transform

Properties of all phase biorthogonal transform matrix and its application in color image compression

Shape Adaptive All Phase Biorthogonal Transform and Its Application in Image Coding

All Phase Inverse Discrete Sine Biorthogonal Transform and Its Application in Image Coding