University of Trento

About: University of Trento is a education organization based out in Trento, Italy. It is known for research contribution in the topics: Population & Context (language use). The organization has 10527 authors who have published 30978 publications receiving 896614 citations. The organization is also known as: Universitá degli Studi di Trento & Universita degli Studi di Trento.

On the structure of finite perimeter sets in step 2 Carnot groups

Abstract: In this article we study codimension 1 rectifiable sets in Carnot groups and we extend classical De Giorgi ’s rectifiability and divergence theorems to the setting of step 2 groups Related problems in higher step Carnot groups are discussed, pointing on new phenomena related to the blow up procedure

Goal-oriented requirement analysis for data warehouse design

Abstract: Several surveys indicate that a significant percentage of data warehouses fail to meet business objectives or are outright failures. One of the reasons for this is that requirement analysis is typically overlooked in real projects. In this paper we propose a goal-oriented approach to requirement analysis for data warehouses, based on the Tropos methodology. Two different perspectives are integrated for requirement analysis: organizational modeling, centered on stakeholders, and decisional modeling, focused on decision makers. Our approach can be employed within both a demand-driven and a mixed supply/demand-driven design framework: in the second case, while the operational sources are still explored to shape hierarchies, user requirements play a fundamental role in restricting the area of interest for analysis and in choosing facts, dimensions, and measures. The methodology proposed, supported by a prototype, is described with reference to a real case study.

PM2K: a flexible program implementing Whole Powder Pattern Modelling

Abstract: Whole Powder Pattern Modelling (WPPM) has been recently proposed as a self- consistent low-bias technique for the microstructural investigation of nanocrystalline materi- als. Through WPPM, a set of physical parameters actually describing the Fourier transform of diffraction line profiles, can be easily extracted from the diffraction data. In order to cope with the need for a higher flexibility (to test, compare and use new line broadening models) and with the request for additional features, the existing code imple- menting WPPM has been redesigned and improved. The result is a general tool for nonlinear least squares minimisation, highly problem- independent and user-customisable through the use of macros or by a custom software de- velopment kit. A set of libraries have been written in the form of plug-ins, actually imple- menting WPPM and the microstructural models proposed in the literature. The work shows software architecture and examples of application of the program to real cases of study.

Ultra Low Power Wake-Up Radios: A Hardware and Networking Survey

Abstract: In wireless environments, transmission and reception costs dominate system power consumption, motivating research effort on new technologies capable of reducing the footprint of the radio, paving the way for the Internet of Things. The most important challenge is to reduce power consumption when receivers are idle, the so called idle-listening cost. One approach proposes switching off the main receiver, then introduces new wake-up circuitry capable of detecting an incoming transmission, optionally discriminating the packet destination using addressing, then switching on the main radio only when required. This wake-up receiver technology represents the ultimate frontier in low power radio communication. In this paper, we present a comprehensive literature review of the research progress in wake-up radio (WuR) hardware and relevant networking software. First, we present an overview of the WuR system architecture, including challenges to hardware design and a comparison of solutions presented throughout the last decade. Next, we present various medium access control and routing protocols as well as diverse ways to exploit WuRs, both as an extension of pre-existing systems and as a new concept to manage low-power networking.

A Simple Extension of the Osher Riemann Solver to Non-conservative Hyperbolic Systems

Abstract: We propose a simple extension of the well-known Riemann solver of Osher and Solomon (Math Comput 38:339---374, 1982) to a certain class of hyperbolic systems in non-conservative form, in particular to shallow-water-type and multi-phase flow models To this end we apply the formalism of path-conservative schemes introduced by Pares (SIAM J Numer Anal 44:300---321, 2006) and Castro et al (Math Comput 75:1103---1134, 2006) For the sake of generality and simplicity, we suggest to compute the inherent path integral numerically using a Gaussian quadrature rule of sufficient accuracy Published path-conservative schemes to date are based on either the Roe upwind method or on centered approaches In comparison to these, the proposed new path-conservative Osher-type scheme has several advantages First, it does not need an entropy fix, in contrast to Roe-type path-conservative schemes Second, our proposed non-conservative Osher scheme is very simple to implement and nonetheless constitutes a complete Riemann solver in the sense that it attributes a different numerical viscosity to each characteristic field present in the relevant Riemann problem; this is in contrast to centered methods or incomplete Riemann solvers that usually neglect intermediate characteristic fields, hence leading to excessive numerical diffusion Finally, the interface jump term is differentiable with respect to its arguments, which is useful for steady-state computations in implicit schemes We also indicate how to extend the method to general unstructured meshes in multiple space dimensions We show applications of the first order version of the proposed path-conservative Osher-type scheme to the shallow water equations with variable bottom topography and to the two-fluid debris flow model of Pitman & Le Then, we apply the higher-order multi-dimensional version of the method to the Baer---Nunziato model of compressible multi-phase flow We also clearly emphasize the limitations of our approach in a special chapter at the end of this article