Partitioned EDF Scheduling in Multicore systems with Quality of Service constraints

International audienceIn this paper we study the partitioned EDF scheduling in a homogeneous multiprocessor environment with Quality of Service (QoS) constraints. The system considered here is a real-time multiprocessor system assumed to be powered by rechargeable batteries. We address the issue of how to best partition a set of firm real-time tasks that can occasionally skip one instance according to a predefined QoS threshold. The main goal is to minimize the energy consumption of the system while offering solutions with respect to transient energy starvation situations the system can experiment. The contribution of the paper is twofold. First, we present a schedulability analysis of firm multiprocessor task sets under QoS constraints. Second we propose new partitionning heuristics integrating skips. The evaluation is conducted from several points of view (minimization of the total processor number, maximization of the spare capacity on each processor)

1.5V fully programmable CMOS Membership Function Generator Circuit with proportional DC-voltage control

A Membership Function Generator Circuit (MFGC) with bias supply of 1.5 Volts and independent DC-voltage programmable functionalities is presented. The realization is based on a programmable differential current mirror and three compact voltage-to-current converters, allowing continuous and quasi-linear adjustment of the center position, height, width and slopes of the triangular/trapezoidal output waveforms. HSPICE simulation results of the proposed circuit using the parameters of a double-poly, three metal layers, 0.5 μm CMOS technology validate the functionality of the proposed architecture, which exhibits a maximum deviation of the linearity in the programmability of 7 %

Polichromatic image sensor with microlenses for stereoscopic acquisition

This paper presents the fabrication of microlenses for integration on a stereoscopic image sensor in CMOS technology and a low-cost technology for fabricating optical filters arrays tuned for the primary colors. The material selected for fabricating the microlens was the AZ4562 positive photoresist and the fabrication process explained. Moreover, the fabrication process presented in this paper is for directly printing the optical filters into a transparent flexible substrate (acetate).This work was fully supported by the Portuguese Foundation for Science and Technology under the project FCT/PTDC/EEA-ELC/109936/2009 and R. P. Rocha is supported by the Foundation for Science and Technology financial grant SFRH/BD/33733/2009

Characterizing the role of vehicular cloud computing in road traffic management

Vehicular cloud computing is envisioned to deliver services that provide traffic safety and efficiency to vehicles. Vehicular cloud computing has great potential to change the contemporary vehicular communication paradigm. Explicitly, the underutilized resources of vehicles can be shared with other vehicles to manage traffic during congestion. These resources include but are not limited to storage, computing power, and Internet connectivity. This study reviews current traffic management systems to analyze the role and significance of vehicular cloud computing in road traffic management. First, an abstraction of the vehicular cloud infrastructure in an urban scenario is presented to explore the vehicular cloud computing process. A taxonomy of vehicular clouds that defines the cloud formation, integration types, and services is presented. A taxonomy of vehicular cloud services is also provided to explore the object types involved and their positions within the vehicular cloud. A comparison of the current state-of-the-art traffic management systems is performed in terms of parameters, such as vehicular ad hoc network infrastructure, Internet dependency, cloud management, scalability, traffic flow control, and emerging services. Potential future challenges and emerging technologies, such as the Internet of vehicles and its incorporation in traffic congestion control, are also discussed. Vehicular cloud computing is envisioned to have a substantial role in the development of smart traffic management solutions and in emerging Internet of vehicles. © The Author(s) 2017

Novel Design of Recursive Differentiator Based on Lattice Wave Digital Filter

In this paper, a novel design of third and fifth order differentiator based on lattice wave digital filter (LWDF), established on optimizing L_1-error approximation function using cuckoo search algorithm (CSA) is proposed. We present a novel realization of minimum multiplier differentiator using LWD structure leading to requirement of optimizing only N coefficients for Nth order differentiator. The gamma coefficients of lattice wave digital differentiator (LWDD) are computed by minimizing the L_1-norm fitness function leading to a flat response. The superiority of the proposed LWDD is evident by comparing it with other differentiators mentioned in the literature. The magnitude response of the designed LWDD is found to be of high accuracy with flat response in a wide frequency range. The simulation and statistical results validates that the designed minimum multiplier LWDD circumvents the existing one in terms of minimum absolute magnitude error, mean relative error (dB) and efficient structural realization, thereby making the proposed LWDD a promising approach to digital differentiator design

High-speed multiple-mode mass-sensing resolves dynamic nanoscale mass distributions

Simultaneously measuring multiple eigenmode frequencies of nanomechanical resonators can determine the position and mass of surface-adsorbed proteins, and could ultimately reveal the mass tomography of nanoscale analytes. However, existing measurement techniques are slow (<1 Hz bandwidth), limiting throughput and preventing use with resonators generating fast transient signals. Here we develop a general platform for independently and simultaneously oscillating multiple modes of mechanical resonators, enabling frequency measurements that can precisely track fast transient signals within a user-defined bandwidth that exceeds 500 Hz. We use this enhanced bandwidth to resolve signals from multiple nanoparticles flowing simultaneously through a suspended nanochannel resonator and show that four resonant modes are sufficient for determining their individual position and mass with an accuracy near 150 nm and 40 attograms throughout their 150-ms transit. We envision that our method can be readily extended to other systems to increase bandwidth, number of modes, or number of resonators.United States. Army Research Office (Grant W911NF-09-0001)Center for Integration of Medicine and Innovative Technology (Contract 09-440)National Science Foundation (U.S.) (Grant 1129359

Energy efficient radio frequency system design for mobile WiMax applications. Modelling, optimisation and measurement of radio frequency power amplifier covering WiMax bandwidth based on the combination of class AB, class B, and C operations.

In today´s digital world, information and communication technology accounts for 3% and 2% of the global power consumption and CO2 emissions respectively. This alarming figure is on an upward trend, as future telecommunications systems and handsets will become even more power hungry since new services with higher bandwidth requirements emerge as part of the so called ¿future internet¿ paradigm. In addition, the mobile handset industry is tightly coupled to the consumer need for more sophisticated handsets with greater battery lifetime. If we cannot make any significant step to reducing the energy gap between the power hungry requirements of future handsets, and what battery technology can deliver, then market penetration for 4G handsets can be at risk. Therefore, energy conservation must be a design objective at the forefront of any system design from the network layer, to the physical and the microelectronic counterparts. In fact, the energy distribution of a handset device is dominated by the energy consumption of the RF hardware, and in particular the power amplifier design. Power amplifier design is a traditional topic that addresses the design challenge of how to obtain a trade-off between linearity and efficiency in order to avoid the introduction of signal distortion, whilst making best use of the available power resources for amplification. However, the present work goes beyond this by investigating a new line of amplifiers that address the green initiatives, namely green power amplifiers. This research work explores how to use the Doherty technique to promote efficiency enhancement and thus energy saving. Five different topologies of RF power amplifiers have been designed with custom-made signal splitters. The design core of the Doherty technique is based on the combination of a class B, class AB and a class C power amplifier working in synergy; which includes 90-degree 2-way power splitter at the input, quarter wavelength transformer at the output, and a new output power combiner. The frequency range for the amplifiers was designed to operate in the 3.4 - 3.6 GHz frequency band of Europe mobile WiMAX. The experimental results show that 30dBm output power can be achieved with 67% power added efficiency (PAE) for the user terminal, and 45dBm with 66% power added efficiency (PAE) for base stations which marks a 14% and 11% respective improvement over current stateof- the-art, while meeting the power output requirements for mobile WiMAX applications

Characterizing the role of vehicular cloud computing in road traffic management

Vehicular cloud computing is envisioned to deliver services that provide traffic safety and efficiency to vehicles. Vehicular cloud computing has great potential to change the contemporary vehicular communication paradigm. Explicitly, the underutilized resources of vehicles can be shared with other vehicles to manage traffic during congestion. These resources include but are not limited to storage, computing power, and Internet connectivity. This study reviews current traffic management systems to analyze the role and significance of vehicular cloud computing in road traffic management. First, an abstraction of the vehicular cloud infrastructure in an urban scenario is presented to explore the vehicular cloud computing process. A taxonomy of vehicular clouds that defines the cloud formation, integration types, and services is presented. A taxonomy of vehicular cloud services is also provided to explore the object types involved and their positions within the vehicular cloud. A comparison of the current state-of-the-art traffic management systems is performed in terms of parameters, such as vehicular ad hoc network infrastructure, Internet dependency, cloud management, scalability, traffic flow control, and emerging services. Potential future challenges and emerging technologies, such as the Internet of vehicles and its incorporation in traffic congestion control, are also discussed. Vehicular cloud computing is envisioned to have a substantial role in the development of smart traffic management solutions and in emerging Internet of vehicles