Data e Ora : Thursday, November 27, 2008 - 15:00
Relatore : Prof. Arnold L. Rosenberg
Affiliazione : ECE Department, Colorado State University and Computer Science Department, University of Massachusetts, Amherst (USA)
Luogo : Aula Magna `A. Lepschy`
Descrizione :

A model for realizing ant-inspired algorithms that coordinate robots within a fixed, geographically constrained environment is proposed and illustrated. The model, dubbed Cellular ANTomata, inverts the relationship between ant-robots and the environment that they navigate: intelligence now resides in the environment rather than in the ants. The Cellular ANTomaton model is illustrated via three proof-of-concept problems: having ants `park` in the nearest corner; having ants seek `food items` (both with and without impenetrable obstacles); having a single ant thread a maze. In all cases, `unintelligent` Cellular-ANTomata-based ant-robots accomplish goals provably more efficiently than traditional `intelligent` ant-robots can; indeed, `intelligent` ant-robots cannot park at all! All of the presented algorithms are scalable and distributed: they provably work within any finite-size environment, and they require no central clock (so they are buildable).

Data e Ora : Thursday, November 20, 2008 - 15:00
Relatore : Dott. Cristian Bonato
Affiliazione : DEI
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Interferometry with quantum states of light has been an active research field for several years. Interference patterns with reduced broadening due to spectral dispersion can be obtained using entangled photons produced by the nonlinear optical process of spontaneous parametric downconversion (dispersion-cancellation effect). Here we describe two new interesting effects. The first one is a new quantum optical interferometer which separates the odd- and even-order spectral phase terms in two distinct subregions of a global interferogram. The second effect is the insensitivity of quantum interference to even-order aberrations (e.g. astigmatism) when working with spatially-anticorrelated entangled photons.

Data e Ora : Thursday, November 13, 2008 - 15:00
Relatore : Prof. Nicola Bernardini
Affiliazione : Conservatorio `C.Pollini` di Padova
Luogo : Aula Magna `A. Lepschy`
Descrizione :

La musica abbraccia una vasta gamma di domini che vanno dal suono al senso e all`interazione sociale; cos� facendo, essa si rivela come importante propulsore di innovazione - sia in termini teoretici, laddove la relazione tra corpo, mente, e materia � una problematica essenziale, che in termini pratici, dove la mediazione di tecnologie musicali svolge un ruolo fondamentale. L`idea che sia la musica a promuovere l`innovazione piuttosto che viceversa non dovrebbe apparire strana: la musica � solidamente ancorata a fondamenti scientifici e come tale � un ambito epistemologico che pu� essere studiato con il rigore scientifico dovuto. Tuttavia, la musica � anche un arte e come tale possiede modalit� che non richiedono necessariamente dimostrazioni scientifiche perch� esse si giustificano in quanto pratiche di significazione. In questo, le necessit� dell`espressione musicale possono dare una spinta formidabile all`innovazione scientifica e tecnologica, e in maniera molto pi� efficace di quanto possano fare i consueti cicli di ricerca e sviluppo. Ma come funziona questa relazione, nella pratica quotidiana? Come riesce una visione artistica ad aprire aree di ricerca inesplorate? Questa presentazione riporter� alcuni esempi in cui la musica ha assunto il ruolo di propulsore di innovazione, illustrando aspetti problematici della relazione tra musica e scienza e azzardando alcune risposte alle domande sopra esposte.

Data e Ora : Thursday, October 30, 2008 - 15:00
Relatore : Ing. Daniele Menon
Affiliazione : DEI
Luogo : Aula Magna `A. Lepschy`
Descrizione :

In the last decade, we observed a considerable diffusion of digital image usage in the everyday life, and consumer electronic devices able to capture digital images, such as digital cameras, PDA, cell phones, etc., have become very popular. In this talk the image acquisition scheme of a typical digital camera will be described, reviewing a number of steps or modules that comprise a camera pipeline. One of the most important steps is the process of reconstructing the full color image from the data acquired with the sensor, called demosaicking. A novel demosaicking technique based on regularization methods will be presented. Moreover, a procedure to increase the resolution will be analyzed, exploiting the local statistics of the acquired digital image.

Data e Ora : Thursday, July 17, 2008 - 15:00
Relatore : Prof. Roberto Merletti
Affiliazione : Politecnico di Torino
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Traditional non invasive electromyography (EMG) is based of differential amplification of a signal detected with two electrodes: either one on the muscle of interest and one at a `reference potential` (monopolar) or both on the muscle of interest (bipolar or single differential). The location of these electrodes is critical and the information provided is limited. Linear or two-dimensional arrays placed on the muscle of interest imply multichannel recording, amplification and processing, but provide a great amount of information, from which the location of the innervation zones can be detected, as well as the features of individual motor units. This information is useful in a variety of applications, ranging from neurophysiology (monitoring control strategies and fatigue of individual motor units), to rehabilitation (assessing effectiveness of treatment), to ergonomics (designing proper workstations), to gynecology (preventing incontinence caused by episiotomy). Basic concepts and applications will be presented.

Data e Ora : Monday, June 23, 2008 - 15:00
Relatore : Prof. Alessandro Mei
Affiliazione : Universita` di Roma La Sapienza
Luogo : Aula Magna `A. Lepschy`
Descrizione :

In this talk we start from the observation that shortest path routing creates congested areas in multi-hop wireless networks. These areas are critical---they generate both security and energy efficiency issues. We attack these problems and set out routing in outer space, a new routing mechanism that transforms any shortest path routing protocol (or approximated versions of it) into a new protocol that does not create congested areas, does not have the associated security-related issues, and does not encourage selfish positioning. Moreover, the network lives longer f the same network using the original routing protocol (in spite of using more energy globally), and dies more gracefully. We also describe applications of our idea to mobility and to a security protocol for the detection of node replication attacks.

Data e Ora : Thursday, June 19, 2008 - 15:00
Relatore : Dr. Mauro Bianco
Affiliazione : University of Texas A&M, USA
Luogo : Aula Magna `A. Lepschy`
Descrizione :

The Standard Template Adaptive Parallel Library (STAPL) is a parallel programming framework that extends C++ and STL with support for parallelism. STAPL provides extensible parallel data structures (pContainers), and generic parallel algorithms (pAlgorithms), as long as a methodology for expressing and composing parallel computations (pRanges). By abstracting much of the complexities of parallelism from the end user, STAPL provides a platform for high productivity parallel software development by enabling the user to focus on algorithmic design instead of lower level parallel implementation issues. In this talk, we provide an overview of the major STAPL components and, as time allows, describe how STAPL have been used to develop important scientific applications (particle transport and protein folding) dramatically reducing the number of lines of code in user programs.
This is joint work with Lawrence Rauchwerger and Nancy Amato, Texas A&M University, USA.

Data e Ora : Thursday, May 29, 2008 - 15:00
Relatore : Prof. Egon Balas
Affiliazione : Carnegie Mellon University, Pittsburgh, USA
Luogo : Sala Riunioni III piano DEI/G
Descrizione :

Standard lift-and-project cuts are derived from a disjunction by solving a cut generating linear program (CGLP) to optimize the multipliers associated with the inequalities on the two sides of the disjunction. These cuts are then strengthened by optimally modularizing the cut coefficients of the integer-constrained variables. Clearly, the result is not an overall optimum. Simultaneous optimization under both aspects is a hard nonlinear integer programming problem. We approximate this overall optimum in the context of generating lift-and-project cuts from the LP simplex tableau by applying disjunctive modularization to the source row for the cut after each pivot. Computational experience will be presented.

Data e Ora : Thursday, April 17, 2008 - 15:00
Relatore : Ing. Giulia Don�
Affiliazione : DEI
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Sports biomechanics is the science that applies the laws of mechanics and physics to athlete performance, in order to gain a greater understanding of motor skills through measurement, modeling and simulation. It operates for meeting the growing demands of coaches, physicians and athletes, to quantitatively assess the essential characteristics of performance. In clinical �gait analysis�, standard protocols have been widely validated and quantitative analysis has become a powerful tool for surgical decision and for post-operative and rehabilitative monitoring. In sports field the great amount of disciplines and the difficulty in standardizing movements have acted as a brake on the systematic use of powerful techniques like stereophotogrammetry. Therefore, one of the purposes of sports research should be the identification of the peculiar characteristics and of the most proficient strategy for each athlete. The monitoring of a group of athletes should be the base for an accurate quantitative assessment of the movement under analysis and for the identification of different skill levels. Then, the knowledge of single athlete�s abilities or deficiencies should help coaches to adjust individual training programs. Moreover, a reliable characterization of the subject should pass through longitudinal monitoring: the athlete might be compared with himself in different times during the training season. The purpose of this study was to investigate the use of principal component analysis for reducing and interpreting sports motion data, while accounting for their original variability. Race walking was chosen as the mean of investigation, because it is a motor task that presents peculiar biomechanical and coordinative demands. An optoelectronic system and a force plate were used to collect and estimate kinematics and kinetics of seven race walkers of international level. Several race walking repetitions were acquired and kinematics and kinetics variables were processed. Principal component analysis summarized the most important information in the data, by representing the variables in a limited number of components that explained most of data variance. Data underwent three different applications of PCA: traditional (t-PCA), functional (f-PCA) and two-stage (2-PCA). A further objective of this study was to evaluate the advantages and disadvantages of the three methods in solving different challenges, because these techniques have not been widely adopted in sports research. A general characterization of race walking biomechanics was pursued, in order to get a full comprehension of the movement under analysis. Then, a robust and complete characterization of the single athlete�s performance strategy was given. All the three methods allowed the exploitation of the relationships among multiple measures in the analysis of race walking data. The most important factors that distinguish athletes according to their skill levels were found out. Moreover, the peculiar technical and coordinative characteristics of each athlete were widely described. Finally, an example of longitudinal monitoring was described. Motion analysis, combined with PCA, was used on data from two subsequent testing sessions, to identify the main improvements caused by training.

Data e Ora : Thursday, March 13, 2008 - 15:00
Relatore : Ing. Ivan Capraro
Affiliazione : DEI
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Negli ultimi anni si � alzato l�interesse per le applicazioni che sfruttano le propriet� quantistiche di singoli fotoni di luce. Una delle pi� importanti � la crittografia quantistica, altre il teletrasporto o la computazione quantistica ottica. Uno dei problemi pi� importanti di queste applicazioni � la discriminazione dei fotoni di segnale dal background noise durante il processo di misura. Per questo vari tipi di filtraggio, spettale, temporale e spaziale sono di fondamentale importanza soprattutto nei casi di propagazione in ambiente rumoroso ad esempio in spazio libero notturno o diurno. Nel seminario verranno presentati i sistemi di filtraggio temporale e spaziale sviluppati per il sistema crittografia quantistica in costruzione al DEI. Verr� inoltre presentato un sistema di filtraggio temporale, concettualmente diverso, in uso per uno strumento di astronomia che lavora a regime di singolo fotone.

Data e Ora : Thursday, March 6, 2008 - 15:00
Relatore : Ing. Luca Corradini
Affiliazione : DEI
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Digital control solutions for switched-mode power supplies (SMPS), traditionally adopted in industrial power systems as well as in high-reliability and mission-critical applications, have recently been introduced in the market of low cost consumer electronics. Digital control ICs inherently have a high degree of programmability and versatility, which allows them to offer features not commonly available in conventional analog solutions. Among these, efficiency maximization strategies for portable and battery-operated equipments, self-tuning capabilities for automatic calibration of the control system, or diagnostic routines for online health monitoring functions. However, digital controllers still fail to be competitive against their analog counterparts in terms of achievable closed-loop dynamic performances. Finite A/D conversion and computational delays, PWM-related delays and quantization effects significantly limit the closed-loop control bandwidth in a digitally controlled SMPS. In this speech, two main topics related to digital control of SMPS are covered, mainly focusing on DC-DC coverters targeted for low voltage, high current applications. The multiple sampling technique is first introduced as a non-conventional sampling strategy, which allows to achieve analog-like performances by strongly reducing the PWM-related delay. Secondly, an auto-tuning technique for automatic calibration of the compensator parameters is discussed. The technique, based on the relay-feedback concept, has been specifically developed to ensure accurate and repeatable tuning results, still maintaining the low hardware complexity dictated by the market of consumer applications.

Data e Ora : Friday, February 8, 2008 - 10:30
Relatore : Ing. Edoardo Rizzi
Affiliazione : Tektronix Communications, Oregon (USA)
Luogo : Aula Magna `A. Lepschy`
Descrizione :

Le reti di comunicazione fissa e mobile hanno ormai permeato tutti gli ambiti della vita personale e lavorativa di ognuno di noi. La qualita` del servizio e la quantita` di dati trasmessi sono cresciute di molto grazie all`introduzione di reti via via piu` intelligenti e a tecnologie che si spingono ormai fino ai limiti vicini alla capacit� teorica (ad es. dettati dal Teorema di Shannon). Tuttavia, la complessita` nella gestione dei sistemi di comunicazione e` cresciuta in modo esponenziale. Questo anche a causa della maggior competizione di mercato e del continuo aumento dell`aspettativa degli utenti in termini di qualita` del servizio.
Le reti di nuova generazione e quelle future promettono di alleviare il problema mediante l`implementazione di meccanismi di controllo automatico della rete e di gestione dinamica del `comportamento` della rete stessa. In altre parole, la rete assume il controllo di se` stessa.
Durante il seminario verranno discusse le principali sfide nella gestione delle reti future, sfide legate soprattutto alla perdita di `visibilita`` e di controllo sull`operato della rete e all`introduzione di nuove tecnologie radio.
Verrano inoltre messe in evidenza aree in cui l`intervento scientifico e di ricerca e` necessario al fine di trovare soluzioni innovative ai problemi che si stanno ponendo.