scholarly journals A New Approach for a Unified Architecture for Type IV DCT/DST with an Efficient Incorporation of Obfuscation Technique

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1656
Author(s):  
Doru Florin Chiper ◽  
Laura-Teodora Cotorobai

This paper aims at solving one challenging problem in designing VLSI chips, namely, the security of the hardware, by presenting a new design approach that incorporates the obfuscation technique in the VLSI implementation of some important DSP algorithms. The proposed method introduces a new approach in obtaining a unified VLSI architecture for computing type IV discrete cosine transform (DCT-IV) and type IV discrete sine transform (DST-IV), with an efficient integration of the obfuscation technique, while maintaining low overheads. The algorithms for these two transforms were restructured in such a way that their structures are fairly similar, and thus they can be implemented on the same VLSI chip and on the same hardware with very few modifications, with the latter being attributed to the pre-processing and post-processing stages. The design proposed uses the regular and modular structures, which are named quasi-correlation, and the architecture is inspired by the paradigm of the systolic array architecture. Thus, the introduced design benefits the security, for the hardware, and also the advantages introduced by the use of the regular and modular structures. A very efficient, unified VLSI architecture for type IV DCT/DST can be obtained, which allows the computation of the two algorithms on the same hardware, allowing an efficient incorporation of the obfuscation technique with very low overheads, and it can be very efficiently implemented, offering high-speed performances and low hardware complexity, with the latter being attributed to the efficient use of the hardware resources for the computation of these two algorithms.

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Doru Chiper

AbstractA new VLSI algorithm and its associated systolic array architecture for a prime length type IV discrete cosine transform is presented. They represent the basis of an efficient design approach for deriving a linear systolic array architecture for type IV DCT. The proposed algorithm uses a regular computational structure called pseudoband correlation structure that is appropriate for a VLSI implementation. The proposed algorithm is then mapped onto a linear systolic array with a small number of I/O channels and low I/O bandwidth. The proposed architecture can be unified with that obtained for type IV DST due to a similar kernel. A highly efficient VLSI chip can be thus obtained with good performance in the architectural topology, computing parallelism, processing speed, hardware complexity and I/O costs similar to those obtained for circular correlation and cyclic convolution computational structures.


Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.


1999 ◽  
Vol 5 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Dingjun Cui ◽  
Ian A. Craighead

The requirements for a special approach for the quality assessment of small high-speed centrifugal fans are outlined and a new parameter designating the noise levels from the product in comprehensive form will be discussed and described as a criterion for such quality assessment.By applying techniques of signal processing and condition monitoring, the sources of the vibration and noise in different sections of the product can be identified, then the noise from each source from different components can be determined. Using this criterion, more aspects of the quality of the products can be assessed and suggestions to improve the quality of the products can be made. Finally, the assessment of a number ofvacuum cleaner motor/fan units available in the commercial market will be presented and compared with conventional specifications. It will be shown that the new parameter provides a more useful indication of appliance quality.


Author(s):  
Mr.M.V. Sathish ◽  
Mrs. Sailaja

A new architecture of multiplier-andaccumulator (MAC) for high-speed arithmetic. By combining multiplication with accumulation and devising a hybrid type of carry save adder (CSA), the performance was improved. Since the accumulator that has the largest delay in MAC was merged into CSA, the overall performance was elevated. The proposing method CSA tree uses 1’s-complement-based radix-2 modified Booth’s algorithm (MBA) and has the modified array for the sign extension in order to increase the bit density of the operands. The proposed MAC showed the superior properties to the standard design in many ways and performance twice as much as the previous research in the similar clock frequency. We expect that the proposed MAC can be adapted to various fields requiring high performance such as the signal processing areas.


Author(s):  
V. Vlasenko ◽  
A. Shiryaeva

New quasi-two-dimensional (2.5D) approach to description of three-dimensional (3D) flows in ducts is proposed. It generalizes quasi-one-dimensional (quasi-1D, 1.5D) theories. Calculations are performed in the (x; y) plane, but variable width of duct in the z direction is taken into account. Derivation of 2.5D approximation equations is given. Tests for verification of 2.5D calculations are proposed. Parametrical 2.5D calculations of flow with hydrogen combustion in an elliptical combustor of a high-speed aircraft, investigated within HEXAFLY-INT international project, are described. Optimal scheme of fuel injection is found and explained. For one regime, 2.5D and 3D calculations are compared. The new approach is recommended for use during preliminary design of combustion chambers.


Robotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 132
Author(s):  
Paolo Righettini ◽  
Roberto Strada ◽  
Filippo Cortinovis

Several industrial robotic applications that require high speed or high stiffness-to-inertia ratios use parallel kinematic robots. In the cases where the critical point of the application is the speed, the compliance of the main mechanical transmissions placed between the actuators and the parallel kinematic structure can be significantly higher than that of the parallel kinematic structure itself. This paper deals with this kind of system, where the overall performance depends on the maximum speed and on the dynamic behavior. Our research proposes a new approach for the investigation of the modes of vibration of the end-effector placed on the robot structure for a system where the transmission’s compliance is not negligible in relation to the flexibility of the parallel kinematic structure. The approach considers the kinematic and dynamic coupling due to the parallel kinematic structure, the system’s mass distribution and the transmission’s stiffness. In the literature, several papers deal with the dynamic vibration analysis of parallel robots. Some of these also consider the transmissions between the motors and the actuated joints. However, these works mainly deal with the modal analysis of the robot’s mechanical structure or the displacement analysis of the transmission’s effects on the positioning error of the end-effector. The discussion of the proposed approach takes into consideration a linear delta robot. The results show that the system’s natural frequencies and the directions of the end-effector’s modal displacements strongly depend on its position in the working space.


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