An efficient hardware implementation of parallel EBCOT algorithm for JPEG 2000

With the augmentation in multimedia technology, demand for high-speed real-time image compression systems has also increased. JPEG 2000 still image compression standard is developed to accommodate such application requirements. Embedded block coding with optimal truncation (EBCOT) is an essential and computationally very demanding part of the compression process of JPEG 2000 image compression standard. Various applications, such as satellite imagery, medical imaging, digital cinema, and others, require high speed and performance EBCOT architecture. In JPEG 2000 standard, the context formation block of EBCOT tier-1 contains high complexity computation and also becomes the bottleneck in this system. In this paper, we propose a fast and efficient VLSI hardware architecture design of context formation for EBCOT tier-1. A high-speed parallel bit-plane coding (BPC) hardware architecture for the EBCOT module in JPEG 2000 is proposed and implemented. Experimental results show that our design outperforms well-known techniques with respect to the processing time. It can reach 70 % reduction when compared to bit plane sequential processing.     

Nonparametric density estimation for positive time series

The Gaussian kernel density estimator is known to have substantial problems for bounded random variables with high density at the boundaries. For independent and identically distributed data, several solutions have been put forward to solve this boundary problem. In this paper, we propose the gamma kernel estimator as a density estimator for positive time series data from a stationary α-mixing process. We derive the mean (integrated) squared error and asymptotic normality. In a Monte Carlo simulation, we generate data from an autoregressive conditional duration model and a stochastic volatility model. We study the local and global behavior of the estimator and we find that the gamma kernel estimator outperforms the local linear density estimator and the Gaussian kernel estimator based on log-transformed data. We also illustrate the good performance of the h-block cross-validation method as a bandwidth selection procedure. An application to data from financial transaction durations and realized volatility is provided.     

Effects of eccentricity defect on the nonlinear dynamic behavior of the mechanism clutch-helical two stage gear

This paper investigates the nonlinear dynamic behavior of an automotive clutch coupled with a helical two stage gear system. The nonlinear dynamic model is simulated by twenty seven degrees of freedom and including three types of nonlinearity: dry friction path, double stage stiffness and spline clearance. The utility of the proposed nonlinear model is illustrated by the industrial need to clearly identify the dynamic behavior of mechanical elements (shafts, bearings, gears, flywheel, pressure plate, hub of the clutch…) and reduce vibration. The governing nonlinear time varying motion equation formulated is resolved by the analytic Runge Kutta method.Then the modeling of the eccentricity defect located on the gear and the flywheel of the clutch is done. The effect of this defect on the nonlinear dynamic behavior of the system is investigated.     

Alumina supported tungsten hydrides, new efficient catalysts for alkane metathesis

Silica and alumina supported tantalum and tungsten hydrides were tested in alkane metathesis, for comparison of their catalytic properties. In propane metathesis [W]–H/Al₂O₃ proves to be twice more efficient than the usual [Ta]–H/SiO₂ catalyst which is still better than [Ta]–H/Al₂O₃ and [W]–H/SiO₂. Tungsten based catalysts lead to a narrower distribution in the products selectivity and to a higher amount of linear products than [Ta]–H/SiO₂. [W]–H/Al₂O₃ is also a better catalyst than [Ta]–H/SiO₂ for butane metathesis but is less efficient with ethane. Whereas the results in the case of propane or butane can involve the higher initial activity and a lower deactivation of the tungsten catalyst, in the case of ethane, mechanistic or kinetic aspects can be envisaged in particular concerning the difficulty to dehydrogenate ethane into ethylene.     

IoT scheduling for higher throughput and lower transmission power

Wireless Networks - The massive increase in the Internet of Things (IoT) has brought a diverse long-range, low-power, and low bit-rate wireless network technologies. The LoRa a low-power wide area...     

Prevalence of JC virus viraemia in HIV-infected patients with or without neurological disorders: a prospective study

Superoxide dismutase (SOD) and catalase (CAT) activities were measured in blood from 420 individuals: control population 126, males and females, age between 50 to 93 years of age without any relevant pathology. Pathological population: 294 patients, males and females, age between 50 to 93 years of age, with some disease in the cardiovascular system and in the osteoarticular system, myoma, prostatic pathologies, Chronic Obstructive Pulmonary Disease (EPOC), and Acute Cerebral Vascular Accident (ACVA). The method of Minami and Yoshikawa (SOD) and the method of Aebi (CAT) were judged the techniques of choice for a population study. Statistical methods: ANOVA and Student's "t". 1) The results were that levels of activity for SOD and CAT were increased for women in control population, and 2) the level of activity for CAT decreases with aging. In the pathological population, we detected: 3) increased activity for SOD in cardiovascular diseases, myomas, EPOC and ACVA. 4) for CAT the level of activity decreases in cardiovascular and prostatic diseases, EPOC and ACVA. 5) while in osteoarticular diseases levels of activity for SOD and CAT were standard, but SOD level decreases with aging, for CAT in cardiovascular diseases and EPOC, too. Both enzymes work to balance the antioxidant system.     

Experimental characterization of a free thermal plume and in interaction with its material environment

This investigation analyses the behaviour of a turbulent thermal plume evolving in a neutral environment and in interaction with its surrounding material. The thermal plume is created by a rectangular hot source. This source is placed at the entry of a vertical parallelepipedic canal opened at the ends. Firstly, we studied the behaviour of a free thermal plume. The flow visualization and the analysis of the thermal and dynamic fields enabled us to detect the existence of two zones during the vertical evolution of the plume. A first zone of plume development followed by a zone of established turbulence. Secondly, we described the structure of a thermal plume produced by the same source inside the vertical canal. In this case the experimental results show clearly a change of the turbulent structure of the flow in comparison with the free plume. This difference is especially characterized by the appearance of a supplementary zone just above the source that is added to the two zones described previously. In addition, the comparison of the two studied configurations showed that the structure of the plume is narrowly affected by the confinement.In order to better define the fine structure of the flow, the temperature fluctuations spectra are analyzed. This spectral analysis enables us to show the fast destruction of the big structures vortexes by the confinement effect to give a smaller structure.     

Fatty acid methyl and ethyl esters obtained from rare seeds from Tunisia: Ammi visnaga,Citrullus colocynthis,Datura stramonium,Ecballium elaterium,and Silybum marianum

This work aims to study the properties of fatty acid methyl and ethyl esters from Tunisian oils in order to assess their potential use as biofuel sources. The oils chosen for this study have been scarcely researched by other authors and are very interesting for a possible exploitation as fuels. Most of them are nonedible sources and all of them can be grown in arid places with no need of supplementary water: the bishop’s weed Ammi visnaga, the bitter apple Citrullus colocynthis, the stramonium Datura stramonium, the devil pickle Ecballium elaterium, and the milk thistle Silybum marianum.