CORDIC Hardware Acceleration Using DMA-Based ISA Extension

The use of RISC-based embedded processors aimed at low cost and low power is becoming an increasingly popular ecosystem for both hardware and software development. High-performance yet low-power embedded processors may be attained via the use of hardware acceleration and Instruction Set Architecture (ISA) extension. Recent publications of AI have demonstrated the use of Coordinate Rotation Digital Computer (CORDIC) as a dedicated low-power solution for solving nonlinear equations applied to Neural Networks (NN). This paper proposes ISA extension to support floating-point CORDIC, providing efficient hardware acceleration for mathematical functions. A new DMA-based ISA extension approach integrated with a pipeline CORDIC accelerator is proposed. The CORDIC ISA extension is directly interfaced with a standard processor data path, allowing efficient implementation of new trigonometric ALU-based custom instructions. The proposed DMA-based CORDIC accelerator can also be used to perform repeated array calculations, offering a significant speedup over software implementations. The proposed accelerator is evaluated on Intel Cyclone-IV FPGA as an extension to Nios processor. Experimental results show a significant speedup of over three orders of magnitude compared with software implementation, while applied to trigonometric arrays, and outperforms the existing commercial CORDIC hardware accelerator.

THEORETICAL COMPLEX ENERGIES OF STARK RESONANCES IN LITHIUM BY OPERATOR PERTURBATION THEORY APPROACH

The theoretical complex energies of the Stark resonances in the lithium atom (non-hydrogenic atomic system) in a DC electric are calculated within the operator form of the modified perturbation theory for the non-H atomic systems. The method includes the physically reasonable distorted-waves approximation in the frame of the formally exact quantum-mechanical procedure. The calculated Stark resonances energies and widths in the lithium atom are calculated and compared with results of calculations on the basis of the method of complex eigenvalue Schrödinger equation by Themelis-Nicolaides, the complex absorbing potential method by Sahoo-Ho and the B-spline-based coordinate rotation method approach by Hui-Yan Meng et al.

A Modified Wavenumber Algorithm of Multi-Layered Structures with Oblique Incidence Based on Full-Matrix Capture

Full-matrix capture (FMC)-based ultrasonic imaging provides good sensitivity to small defects in non-destructive testing and has gradually become a mainstream research topic. Many corresponding algorithms have been developed, e.g., the total focusing method (TFM). However, the efficiency of the TFM is limited, especially in multi-layered structures. Although the appearance of wavenumber algorithms, such as extended phase-shift migration (EPSM) methods, has improved imaging efficiency, these methods cannot be applied to cases with oblique incidence. Therefore, a modified wavenumber method for full-matrix imaging of multi-layered structures with oblique array incidence is proposed. This method performs a coordinate rotation in the frequency domain to adapt it to the oblique incidence. It then utilizes wave-field extrapolation to migrate the transmitting and receiving wave field to each imaging line, and a correlation imaging condition is used to reconstruct a total focused image. The proposed method can deal with any incident angle without precision loss. Moreover, it inherits the computational efficiency advantages of the wavenumber algorithms. The simulation and experimental results show that the proposed method performs better in terms of accuracy and efficiency than the TFM. Specifically, it is nearly 60 times faster than the TFM when processing an FMC dataset with a size of 4096 × 64 × 64.

Exploring the CORDIC Algorithm and Clock-Gating for Power-Efficient Fast Fourier Transform Hardware Architectures

This work explores hardware-oriented optimizations for the CORDIC (COordinate Rotation Digital Computer) algorithm investigating the power-efficiency improvements employing N-point Fast Fourier Transform (FFT) hardware architectures. We introduced three hardware-oriented optimizations for the CORDIC: (a) improving the signal extension, (b) removing the angle accumulation and (c) eliminating the redundancies in the iterations, both unnecessary when processing the FFT processing. Fully sequential FFT architectures of 32, 64, 128, and 256 points were synthesized employing ST 65 nm standard cell libraries. The results show up to 38% of power savings on average when using our best CORDIC optimization proposal to the FFT architecture comparing to the explicit multiply-based butterfly version. Moreover, when combining our best CORDIC optimization with the clock-gating technique, the power savings rises to 78.5% on average for N-point FFT.

Research on political text metaphor translation system based on web data mining technology

In order to improve the translation effect of political text metaphors, based on Web data mining technology, this paper constructs a political text metaphor translation system based on Web data mining technology. Aiming at the two shortcomings of the selection of the initial center point of the K-Means algorithm and the isolated points, this paper gives a solution to the ICKM algorithm that combines the density parameter and the coordinate rotation algorithm. The algorithm uses the object with the largest density parameter as the first center point, and uses the KCR algorithm to find the next center point, which avoids the influence of isolated points on the data sample to a certain extent. The constructed political text metaphor translation system based on Web data mining technology needs to accurately translate political texts and also needs to meet the requirements of metaphor translation. Finally, this paper designs experiments to verify the system performance. The research results show that the system constructed in this paper can meet the needs of political text metaphor translation.

Microdisplacement Measurement Based on F-P Etalon: Processing Method and Experiments

Herein, a processing method is proposed for accurate microdisplacement measurements from a 2D Fabry–Perot (F-P) fringe pattern. The core of the processing algorithm uses the F-P interference imaging concentric ring pattern to accurately calculate the centre coordinates of the concentric ring. The influencing factors of measurement were analysed, and the basic idea of data processing was provided. In particular, the coordinate rotation by the 45-degree method (CR) was improved; consequently, the virtual pixel interval was reduced by half, and the calculation accuracy of the circle centre coordinate was improved. Experiments were conducted to analyse the influence of the subdivision and circle fitting methods. The results show that the proposed secondary coordinate rotation (SCR) by 45 degrees method can obtain higher accuracy of the centre coordinate than the CR method, and that the multichord averaging method (MCAM) is more suitable for calculation of the centre coordinate than the circular regression method (CRM). Displacement measurement experiments were performed. The results show that the standard experimental deviation of the centre of the circle is approximately 0.009 µm, and the extended uncertainty of the displacement measurement in the range of 5 mm is approximately 0.03 μm. The data processing method studied in this study can be widely used in the field of F-P interferometry.

The Space-evolution Frame as Alternative to Space-time

As a alternative to Minkowski spacetime frame, this paper propose a four dimensional Euclidean space that combine three spacial dimension with evolution instead of time. It is called space-evolution, in which time is considered as world line length and is absolute. The space-evolution frame provide a new perspective for understanding of time, space and special relativity. The new frame is self-consistent without losing compatibility to special relativity, the Lorentz transform and its predictions could be derived geometrically by simple coordinate rotation.

The Space-evolution Frame as Alternative to Space-time

As a alternative to Minkowski spacetime frame, this paper propose a four dimensional Euclidean space that combine three spacial dimension with evolution instead of time. It is called space-evolution, in which time is considered as world line length and is absolute. The space-evolution frame provide a new perspective for understanding of time, space and special relativity. It is self-consistent without losing compatibility to special relativity, the Lorentz transform and its predictions could be derived geometrically by simple coordinate rotation.