The extended conformal theory of Luttinger systems

We describe the recently introduced method of algebraic bosonization of the $(1+1)$-dimensional Luttinger systems by discussing in detail the specific case of the Calogero-Sutherland model, and mentioning the hard-core Bose gas. We also compare our findings with the exact Bethe Ansatz results.Comment: 9 pages, plain Latex file, ,based on a talk given by S. Sciuto at the II International Sakharov Conference on Physics, Moscow, Russia, 20-24 May 9

The extended conformal theory of the Calogero-Sutherland model

We describe the recently introduced method of Algebraic Bosonization of (1+1)-dimensional fermionic systems by discussing the specific case of the Calogero-Sutherland model. A comparison with the Bethe Ansatz results is also presented.Comment: 12 pages, plain LaTeX, no figures; To appear in the proceedings of the IV Meeting "Common Trends in Condensed Matter and High Energy Physics", Chia Laguna, Cagliari, Italy, 3-10 Sep. 199

Electrical and ultraviolet characterization of 4H-SiC Schottky photodiodes

Fabrication and electrical and optical characterization of 4H-SiC Schottky UV photodetectors with nickel silicide interdigitated contacts is reported. Dark capacitance and current measurements as a function of applied voltage over the temperature range 20 °C – 120 °C are presented. The results show consistent performance among devices. Their leakage current density, at the highest investigated temperature (120 °C), is in the range of nA/cm2 at high internal electric field. Properties such as barrier height and ideality factor are also computed as a function of temperature. The responsivities of the diodes as functions of applied voltage were measured using a UV spectrophotometer in the wavelength range 200 nm - 380 nm and compared with theoretically calculated values. The devices had a mean peak responsivity of 0.093 A/W at 270 nm and −15 V reverse bias

A Power-Efficient Methodology for Mapping Applications on Multi-Processor System-on-Chip Architectures

This work introduces an application mapping methodology and case study for multi-processor on-chip architectures. Starting from the description of an application in standard sequential code (e.g. in C), first the application is profiled, parallelized when possible, then its components are moved to hardware implementation when necessary to satisfy performance and power constraints. After mapping, with the use of hardware objects to handle concurrency, the application power consumption can be further optimized by a task-based scheduler for the remaining software part, without the need for operating system support. The key contributions of this work are: a methodology for high-level hardware/software partitioning that allows the designer to use the same code for both hardware and software models for simulation, providing nevertheless preliminary estimations for timing and power consumption; and a task-based scheduling algorithm that does not require operating system support. The methodology has been applied to the co-exploration of an industrial case study: an MPEG4 VGA real-time encoder

Performance of Smart Materials-Based Instrumentation for Force Measurements in Biomedical Applications: A Methodological Review

The introduction of smart materials will become increasingly relevant as biomedical technologies progress. Smart materials sense and respond to external stimuli (e.g., chemical, electrical, mechanical, or magnetic signals) or environmental circumstances (e.g., temperature, illuminance, acidity, or humidity), and provide versatile platforms for studying various biological processes because of the numerous analogies between smart materials and biological systems. Several applications based on this class of materials are being developed using different sensing principles and fabrication technologies. In the biomedical field, force sensors are used to characterize tissues and cells, as feedback to develop smart surgical instruments in order to carry out minimally invasive surgery. In this regard, the present work provides an overview of the recent scientific literature regarding the developments in force measurement methods for biomedical applications involving smart materials. In particular, performance evaluation of the main methods proposed in the literature is reviewed on the basis of their results and applications, focusing on their metrological characteristics, such as measuring range, linearity, and measurement accuracy. Classification of smart materials-based force measurement methods is proposed according to their potential applications, highlighting advantages and disadvantages

An entropy evaluation algorithm to improve transmission efficiency of compressed data in pervasive healthcare mobile sensor networks

Data transmission is the most critical operation for mobile sensors networks in term of energy waste. Particularly in pervasive healthcare sensors network it is paramount to preserve the quality of service also by means of energy saving policies. Communication and data transmission are among the most critical operation for such devises in term of energy waste. In this paper we present a novel approach to increase battery life-span by means of shorter transmission due to data compression. On the other hand, since this latter operation has a non-neglectable energy cost, we developed a compression efficiency estimator based on the evaluation of the absolute and relative entropy. Such algorithm provides us with a fast mean for the evaluation of data compressibility. Since mobile wireless sensor networks are prone to battery discharge-related problems, such an evaluation can be used to improve the electrical efficiency of data communication. In facts the developed technique, due to its independence from the string or file length, is extremely robust both for small and big data files, as well as to evaluate whether or not to compress data before transmission. Since the proposed solution provides a quantitative analysis of the source's entropy and the related statistics, it has been implemented as a preprocessing step before transmission. A dynamic threshold defines whether or not to invoke a compression subroutine. Such a subroutine should be expected to greatly reduce the transmission length. On the other hand a data compression algorithm should be used only when the energy gain of the reduced transmission time is presumably greater than the energy used to run the compression software. In this paper we developed an automatic evaluation system in order to optimize the data transmission in mobile sensor networks, by compressing data only when this action is presumed to be energetically efficient. We tested the proposed algorithm by using the Canterbury Corpus as well as standard pictorial data as benchmark test. The implemented system has been proven to be time-inexpensive with respect to a compression algorithm. Finally the computational complexity of the proposed approach is virtually neglectable with respect to the compression and transmission routines themselves

Using Speculative Computation and Parallelizing Techniques to Improve Scheduling of Control based Designs

partially_open5Recent research results have seen the application of parallelizing techniques to high-level synthesis. In particular, the effect of speculative code transformations on mixed control-data flow designs has demonstrated effective results on schedule lengths. In this paper we first analyze the use of the control and data dependence graph as an intermediate representation that provides the possibility of extracting the maximum parallelism. Then we analyze the scheduling problem by formulating an approach based on Integer Linear Programming (ILP) to minimize the number of control steps given the amount of resources. We improve the already proposed ILP scheduling approaches by introducing a new conditional resource sharing constraint which is then extended to the case of speculative computation. The ILP formulation has been solved by using a Branch and Cut framework which provides better results than standard branch and bound techniquesR. Cordone; F. Ferrandi; G. Palermo; M. Santambrogio; D. SciutoR., Cordone; Ferrandi, Fabrizio; Palermo, Gianluca; Santambrogio, MARCO DOMENICO; Sciuto, Donatell