MPARM: Exploring the Multi-Processor SoC Design Space with SystemC

Technology is making the integration of a large number of processors on the same silicon die technically feasible. These multi-processor systems-on-chip (MP-SoC) can provide a high degree of flexibility and represent the most efficient architectural solution for supporting multimedia applications, characterized by the request for highly parallel computation. As a consequence, tools for the simulation of these systems are needed for the design stage, with the distinctive requirement of simulation speed, accuracy and capability to support design space exploration. We developed a complete simulation platform for a MP-SoC called MP-ARM, based on SystemC as modelling and simulation environment, and including models for processors, the AMBA bus compliant communication architecture, memory models and support for parallel programming. A fully operating linux version for embedded systems has been ported on this platform, and a cross-toolchain has been developed as well. Our MP simulation environment turns out to be a powerful tool for the MP-SOC design stage. As an example thereof, we use our tool to evaluate the impact on system performance of architectural parameters and of bus arbitration policies, showing that the effectiveness of a particular system configuration strongly depends on the application domain and the generated traffic profile.Luca Benini received the B.S. degree (summa cum laude) in electrical engineering from the University of Bologna, Italy, in 1991, and the M.S. and Ph.D. degrees in electrical engineering from Stanford University in 1994 and 1997, respectively. He is an associate professor in the department of electronics and computer science in the University of Bologna. He also holds visiting researcher positions at Stanford University and the Hewlett-Packard Laboratories, Palo Alto, CA.Dr. Benini’s research interests are in all aspects of computer-aided design of digital circuits, with special emphasis on low-power applications, and in the design of portable systems. He is co-author of the book: Dynamic Power management, Design Techniques and CAD tools, Kluwer 1998.Dr. Benini is a member of the technical program committee for several technical conferences, including the Design Automation Conference, the International Symposium on Low Power Design and the International symposium on Hardware-Software Codesign.Davide Bertozzi received the B.S. degree in electrical engineering from the University of Bologna, Bologna, Italy, in 1999.He is currently pursuing the Ph.D. degree at the same University and is expected to graduate in 2003. His research interests concern the development of SoC co-simulation platforms, exploration of SoC communication architectures and low power system design.Alessandro Bogliolo received the Laurea degree in electrical engineering and the Ph.D. degree in electrical engineering and computer science from the University of Bologna, Bologna, Italy, in 1992 and 1998.In 1995 and 1996 he was a Visiting Scholar at the Computer Systems Laboratory (CSL), Stanford University, Stanford, CA.From 1999 to 2002 he was an Assistant Professor at the Department of Engineering (DI) of the University of Ferrara, Ferrara, Italy. Since 2002 he’s been with the Information Science and Technology Institute (STI) of the University of Urbino, Urbino, Italy, as Associate Professor. His research interests are mainly in the area of digital integrated circuits and systems, with emphasis on low power and signal integrity.Francesco Menichelli was born in Rome in 1976. He received the Electronic Engineering degree in 2001 at the University of Rome “La Sapienza”. From 2002 he is a Ph.D. student in Electronic Engineering at “La Sapienza” University of Rome.His scientific interests focus on low power digital design, and in particular in level tecniques for low power consumption, power modeling and simulation of digital systems.Mauro Olivieri received a Master degree in electronic engineering “cum laude” in 1991 and a Ph.D. degree in electronic and computer engineering in 1994 from the University of Genoa, Italy, where he also worked as an assistant professor. In 1998 he joined the University of Rome “La Sapienza”, where he is currently associate professor in electronics. His research interests are digital system-on-chips and microprocessor core design. Prof. Olivieri supervises several research projects supported by private and public fundings in the field of VLSI system design.     

Design of photocatalytic reactors made easy by considering the photons as immaterial reactants

While it is quite obvious that photons have an essential role in photochemical and photocatalytic processes, it is not simple to analyse the radiation process.A simple approach is presented on the assumption that photons can be treated as immaterial reactants. It is then possible to evaluate the radiation process in terms of parameters such as conversion, selectivity and yield, which are common in the conventional reaction engineering, and of an additional parameter, a volume efficiency factor, which accounts for the exploitation of the reaction volume as the result of the inevitable attenuation of the radiation in the transport through the participating medium.Attention has also been focused on the validation of kinetic data when, as it is usually done, they are interpreted in terms of volume averages.Finally, guidelines have been prepared to support preliminary phases of analysis and/or design of a photocatalytic reactor.     

Evidence of the CH···O HydrogenBonding in Imidazolium-Based Ionic Liquids from Far-Infrared Spectroscopy Measurements and DFT Calculations

Knowledge of all the intermolecular forces occurring in ionic liquids (ILs) is essential to master their properties. Aiming at investigating the weaker hydrogen bonding in aprotic liquids, the present work combined computational study and far-infrared spectroscopy on four imidazolium-based ILs with different anions. The DFT calculations of the ionic couples, using the ωB97X-D functional and considering both the empirical dispersion corrections and the presence of a polar solvent, show that, for all samples, the lowest energy configurations of the ion pair present H atoms, directly bound to C atoms of the cation and close to O atoms of the anion, capable of creating moderate to weak hydrogen bonding with anions. For the liquids containing anions of higher bonding ability, the absorption curves generated from the calculated vibrational frequencies and intensities show absorption bands between 100 and 125 cm⁻¹ corresponding to the stretching of the hydrogen bond. These indications are in complete agreement with the presently reported temperature dependence of the far-infrared spectrum, where the stretching modes of the hydrogen bonding are detected only for samples presenting a moderate interaction and become particularly prominent at low temperatures. Moreover, from the analysis of the infrared spectra, the occurrence of various phase transitions as a function of temperature was detected, and the difference in the average energy between the H-bonded and the dispersion-governed molecular configurations was evaluated.     

Outlier Detection And Estimation In NonLinear Time Series

Abstract. The problem of identifying the time location and estimating the amplitude of outliers in nonlinear time series is addressed. A model‐based method is proposed for detecting the presence of additive or innovational outliers when the series is generated by a general nonlinear model. We use this method for identifying and estimating outliers in bilinear, self‐exciting threshold autoregressive and exponential autoregressive models. A simulation study is performed to test the proposed procedures and comparing them with the methods based on linear models and linear interpolators. Finally, our results are applied for detecting outliers in the Canadian lynx trappings and in the sunspot numbers data.     

Apparatus for the production of hydrogen from sodium borohydride in alkaline solution

Extended application of hydrogen as energy carrier demands an economical, safe and reliable technology for storage. In particular, chemical hydrides appear as capable and promising to overcome the issues related to hydrogen safety and handling and to be considered competitive with respect to conventional fuels.     

Normal maps vs. visible images: Comparing classifiers and combining modalities

This work investigates face recognition based on normal maps, and the performance improvement that can be obtained when exploiting it within a multimodal system, where a further independent module processes visible images. We first propose a technique to align two 3D models of a face by means of normal maps, which is very fast while providing an accuracy comparable to well-known and more general techniques such as Iterative Closest Point (ICP). Moreover, we propose a matching criterion based on a technique which exploits difference maps. It does not reduce the dimension of the feature space, but performs a weighted matching between two normal maps. In the second place, we explore the range of performances offered by different linear and nonlinear classifiers, when applied to the normal maps generated from the above aligned models. Such experiments highlight the added value of chromatic information contained in normal maps. We analyse a solid list of classifiers which were selected due to their historical reference value (e.g. Principal Component Analysis) or to their good performances in the bidimensional setting (Linear Discriminant Analysis, Partitioned Iterated Function Systems). Last but not least, we perform experiments to measure how different ways of combining normal maps and visible images can enhance the results obtained by the single recognition systems, given that specific characteristics of the images are taken into account. For these last experiments we only consider the classifier giving the best average results in the preceding ones, namely the PIFS-based one.     

Liquid electrolyte positioning along the device channel influences the operation of Organic Electro-Chemical Transistors

In this work, we show the influence of the liquid electrolyte adsorption by porous films made of poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate), PEDOT:PSS, on the operation of an Organic Electro-Chemical Transistor with an active channel based on these polymeric films. In particular, the effect of film hydration on device performance is evaluated by studying its electrical response as a function of the spatial position between the electrolyte and the channel electrodes. This is done by depositing a PEDOT:PSS film on a super-hydrophobic surface aimed at controlling the electrolyte confinement next to the electrodes. The device response shows that the confinement of ionic liquids near to the drain electrode results in a worsening of the current modulation. This result has been interpreted in the light of studies dealing with the transport of ions in semiconducting polymers, indicating that the electrolyte adsorption by the polymeric film implies the formation of liquid pathways inside its bulk. These pathways, in particular, affect the device response because they are able to assist the drift of ionic species in the electrolyte towards the drain electrode. The effect of electrolyte adsorption on the device operation is confirmed by means of moving-front measurements, and is related to the reproducibility of the device operation curves by measuring repeatedly its electrical response.     

Advanced microstructural characterization of plasma-sprayed zirconia coatings over extended length scales

Achieving control of the microstructure of plasma-sprayed thermal barrier coating (TBC) systems offers an opportunity to tailor coating properties to demanding applications. Accomplishing this requires a fundamental understanding of the correlations among processing, microstructure development, and related TBC properties. This article describes the quantitative characterization of the microstructure of plasma-sprayed partially stabilized zirconia (PSZ) coatings by means of x-ray and neutron-scattering imaging techniques. Small-angle neutron scattering, ultra-small-angle x-ray scattering, and x-ray microtomography were used to characterize and visualize the nature and structure of the features in these material systems. In addition, the influence of processing parameters on microstructure development is discussed along with thermal cycling effects on the pore morphology, and their resultant influence of the porosity on the thermal conductivity and elastic modulus of plasma-sprayed PSZ TBCs.