On the Enhancement of the Reconstruction Accuracy obtained with a Multi-Source/Multi-Illumination Inverse Scattering Technique

This paper explores the possibility of enhancing the available information content of scattered data by means of an innovative Multi-Source strategy. The approach exploits the scattering interactions between scatterer and probing source when the investigation domain is illuminated by different (in terms of radiation patterns) illuminations. The results of a set of representative numerical simulations are shown to point out the potentialities of the inversion strategy

Full-Vectorial Three-Dimensional Microwave Imaging Through the Iterative Multi-Scaling Strategy: a Preliminary Assessment

In this paper, a multi-scaling strategy for full-vectorial three-dimensional inverse scattering problems is presented. The approach is fully iterative and it avoids solving any forward problem at each step. Thanks to the adaptive multi-resolution model, which offers considerable flexibility for the inclusion of the a-priori knowledge and of the knowledge acquired during the iterative steps of the multi-scaling process, the overall computational burden is considerably reduced. This allows to balance effectively the trade-off between computational costs and achievable resolution accuracy. The effectiveness of the proposed approach is demonstrated through a selected set of preliminary experiments using homogeneous dielectric scatterers in a noisy synthetic environment

An Iterative Procedure for Combining the Advantages of a Multi-Frequency and Multi-Resolution Inversion Algorithm

Starting from the iterative multi�]scaling approach previously studied for monochromatic illuminations, two multi�]resolution strategies for dealing with multi�]frequency inverse scattering experiments have been developed. The first procedure is based on the integration of the iterative multi�]scaling algorithm into a frequency�]hopping reconstruction scheme, while in the second one the multi�]frequency data are simultaneously processed exploiting a multi�]resolution expansion of the problem unknowns. The numerical and the experimental analysis presented in this contribution concern with a preliminary assessment of the reconstruction effectiveness of the proposed approaches in comparison with a monochromatic multi�]step process. This is the author's version of the final version available at IEEE

A Comparison Between Deterministic and Stochastic Inversions of Phaseless Data for Microwave Imaging

The development of microwave imaging techniques and their application are strongly related to the possibility to realize fast and cheap measurement systems. On the contrary, the phase acquisition usually requires complex and expensive apparatus and it turns out to be critical especially at high frequencies. Moreover, holographic and interferometric methods, often used in optical applications [1], are usually characterized by a high computational burden because of the time‐consuming data post‐processing. Consequently, the study of efficient algorithms for the reconstruction from amplitude‐only data is necessary in several applications. Also published in: Progress In Electromagnetics Research Symposium Abstracts, Hangzhou, China, March 24-28, 200

Structural resolution for abstract compilation of object-oriented languages

We propose abstract compilation for precise static type analysis of object-oriented languages based on coinductive logic programming. Source code is translated to a logic program, then type-checking and inference problems amount to queries to be solved with respect to the resulting logic program. We exploit a coinductive semantics to deal with infinite terms and proofs produced by recursive types and methods. Thanks to the recent notion of structural resolution for coinductive logic programming, we are able to infer very precise type information, including a class of irrational recursive types causing non-termination for previously considered coinductive semantics. We also show how to transform logic programs to make them satisfy the preconditions for the operational semantics of structural resolution, and we prove this step does not affect the semantics of the logic program.Comment: In Proceedings CoALP-Ty'16, arXiv:1709.0419

Analysis of Voltage Distribution and Connections within a High-Frequency Hairpin Winding Model

In the last years the adoption of hairpin windings is increasing, especially in the automotive sector, mainly due to their inherently high fill factor and electric loading capability. A critical aspect related to the reliability and lifetime of every winding typology is the voltage stress due to the uneven voltage distribution. This phenomenon has already been largely analyzed in conventional stranded conductors, while a few studies are available for hairpin windings. With the spreading of wide bandgap devices, the investigation on voltage distribution becomes an ever-timely topic due to their short rise times. This paper presents an analysis of the uneven voltage distribution triggered within hairpin windings by a low rise time waveform, using a complete high-frequency winding model. The different options to series-connect different paths are investigated, providing simple but essential guidelines to reduce the electrical stress within hairpin windings. © 20XX IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis paper reflects only the author's view. JU is not responsible for any use that may be made of the information it contains

Recent Advances in the Iterative Multizooming Reconstruction of Nonmeasurable Equivalent Current Densities for Non-Invasive Diagnostic Applications

In the framework of the inversion of electromagnetic data, several methodologies consider the introduction of an equivalent current density defined into the dielectric domain to be reconstructed

Towards Runtime Monitoring of Node.js and Its Application to the Internet of Things

In the last years Node.js has emerged as a framework particularly suitable for implementing lightweight IoT applications, thanks to its underlying asynchronous event-driven, non blocking I/O model. However, verifying the correctness of programs with asynchronous nested callbacks is quite difficult, and, hence, runtime monitoring can be a valuable support to tackle such a complex task. Runtime monitoring is a useful software verification technique that complements static analysis and testing, but has not been yet fully explored in the context of Internet of Things (IoT) systems. Trace expressions have been successfully employed for runtime monitoring in widespread multiagent system platforms. Recently, their expressive power has been extended to allow parametric specifications on data that can be captured and monitored only at runtime. Furthermore, they can be language and system agnostic, through the notion of event domain and type. This paper investigates the use of parametric trace expressions as a first step towards runtime monitoring of programs developed in Node.js and Node-RED, a flow-based IoT programming tool built on top of Node.js. Runtime verification of such systems is a task that mostly seems to have been overlooked so far in the literature. A prototype implementing the proposed system for Node.js, in order to dynamically check with trace expressions the correct usage of API functions, is presented. The tool exploits the dynamic analysis framework Jalangi for monitoring Node.js programs and allows detection of errors that would be difficult to catch with other techniques. Furthermore, it offers a simple REST interface which can be exploited for runtime verification of Node-RED components, and, more generally, IoT devices

Multistress characterization of fault mechanisms in aerospace electric actuators

The concept behind the More Electric Aircraft (MEA) is the progressive electrification of on-board actuators and services. It is a way to reduce or eliminate the dependence on hydraulic, mechanical and the bleed air/pneumatic systems and pursue efficiency, reliability and maintainability. This paper presents a specialised test rig whose main objective is to assess insulation lifespan modelling under various stress conditions, especially investigating the interaction between ageing factors. The test set-up is able to reproduce a multitude of environmental and operational conditions at which electric drives and motors, used in aerospace applications, are subjected. It is thus possible to tailor the test cycle in order to mimic the working cycle of an electrical motor during real operation in aircraft application. The developed test-rig is aimed at projecting the technology readiness to higher levels of maturity, in the context of electrical motors and drives for aerospace applications. Its other objective is to validate and support the development of a comprehensive insulation degradation model