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Computational modeling of turn-taking dynamics in spoken conversations
No full textThe study of human interaction dynamics has been at the center for multiple research disciplines in- cluding computer and social sciences, conversational analysis and psychology, for over decades. Recent interest has been shown with the aim of designing computational models to improve human-machine interaction system as well as support humans in their decision-making process. Turn-taking is one of the key aspects of conversational dynamics in dyadic conversations and is an integral part of human- human, and human-machine interaction systems. It is used for discourse organization of a conversation by means of explicit phrasing, intonation, and pausing, and it involves intricate timing. In verbal (e.g., telephone) conversation, the turn transitions are facilitated by inter- and intra- speaker silences and over- laps. In early research of turn-taking in the speech community, the studies include durational aspects of turns, cues for turn yielding intention and lastly designing turn transition modeling for spoken dia- log agents. Compared to the studies of turn transitions very few works have been done for classifying overlap discourse, especially the competitive act of overlaps and function of silences.
Given the limitations of the current state-of-the-art, this dissertation focuses on two aspects of con- versational dynamics: 1) design automated computational models for analyzing turn-taking behavior in a dyadic conversation, 2) predict the outcome of the conversations, i.e., observed user satisfaction, using turn-taking descriptors, and later these two aspects are used to design a conversational profile for each speaker using turn-taking behavior and the outcome of the conversations. The analysis, experiments, and evaluation has been done on a large dataset of Italian call-center spoken conversations where customers and agents are engaged in real problem-solving tasks.
Towards solving our research goal, the challenges include automatically segmenting and aligning speakers’ channel from the speech signal, identifying and labeling the turn-types and its functional aspects. The task becomes more challenging due to the presence of overlapping speech. To model turn- taking behavior, the intension behind these overlapping turns needed to be considered. However, among all, the most critical question is how to model observed user satisfaction in a dyadic conversation and what properties of turn-taking behavior can be used to represent and predict the outcome.
Thus, the computational models for analyzing turn-taking dynamics, in this dissertation includes au- tomatic segmenting and labeling turn types, categorization of competitive vs non-competitive overlaps, silences (e.g., lapse, pauses) and functions of turns in terms of dialog acts.
The novel contributions of the work presented here are to
1. design of a fully automated turn segmentation and labeling (e.g., agent vs customer’s turn, lapse within the speaker, and overlap) system.
2. the design of annotation guidelines for segmenting and annotating the speech overlaps with the competitive and non-competitive labels.
3. demonstrate how different channels of information such as acoustic, linguistic, and psycholin- guistic feature sets perform in the classification of competitive vs non-competitive overlaps.
4. study the role of speakers and context (i.e., agents’ and customers’ speech) for conveying the information of competitiveness for each individual feature set and their combinations.
5. investigate the function of long silences towards the information flow in a dyadic conversation.
The extracted turn-taking cues is then used to automatically predict the outcome of the conversation, which is modeled from continuous manifestations of emotion. The contributions include
1. modeling the state of the observed user satisfaction in terms of the final emotional manifestation of the customer (i.e., user).
2. analysis and modeling turn-taking properties to display how each turn type influence the user satisfaction.
3. study of how turn-taking behavior changes within each emotional state.
Based on the studies conducted in this work, it is demonstrated that turn-taking behavior, specially competitiveness of overlaps, is more than just an organizational tool in daily human interactions. It represents the beneficial information and contains the power to predict the outcome of the conversation in terms of satisfaction vs not-satisfaction. Combining the turn-taking behavior and the outcome of the conversation, the final and resultant goal is to design a conversational profile for each speaker. Such profiled information not only facilitate domain experts but also would be useful to the call center agent in real time.
These systems are fully automated and no human intervention is required. The findings are po- tentially relevant to the research of overlapping speech and automatic analysis of human-human and human-machine interactions
Analysis of users' psycho-physiological parameters in response to affective multimedia - A mutlimodal and implicit approach for user-centric multimedia tagging
No full textThe affective state of a user, during an interaction with a computer, is a great source of information for the computer in order to (i) employ the information for adapting an interaction, make the interaction flawless, leading in adaptive affective interfaces. The computer may also use emotional responses of a user to some affective multimedia content (ii) to tag the multimedia content with affective labels. The second is very useful to create affective profiles of users within real world applications for user-centric multimedia retrieval.
Affective responses of users could be collected either explicitly (i.e. users directly assess their own emotions through computer interfaces) or implicitly (i.e. via sensors that collect psycho-physiological signals such as facial expressions, vocal clues, neuro-physiological signals, gestures and body postures).
The major contributions of this thesis are as follows: (i) We present (and made publicly available) the very first multimodal dataset that includes the MEG brain signals, facial videos and some peripheral physisological signals of 30 users in response to two sets of affective dynamic stimuli. The dataset is recorded via cutting-edge lab equipments in highly controlled lab environments, facilitating proper analysis of MEG brain responses for affective neuro-science research.
(ii) We then present two other multimodal datasets that we recorded using off-the-shelves market-available sensors for the purpose of analyzing users' affective responses to video clips and computer-generated music excerpts. The stimuli are selectively chosen to evoke certain target emotions. The first dataset also includes the BigFive personality traits of individuals and we show that it is possible to infer users' personality traits given their spontaneous reactions to affective videos. Both multimodal datasets are acquired via commercial sensors that are prone to noise artifacts that lead to some noisy uni-modal recordings. We made both datasets publicly available together with quality-assessments of each signal recording. Within the research on the second dataset we present a multimodal inference system that jointly considers the quality of signals and ends up with highly signal noise tolerance. We also show that peripheral physiological signals include patterns that are similar across user. We develop a cross-user affect recognition system that is successfully validated via a leave-one-subject-out cross-validation scheme on the second dataset.
(iii) We also present a crowdsourcing protocol for the collection of time-continuous affect annotations for videos. We collect a dataset of affective annotations for 12 videos with the contribution of over 1500 crowd-workers. We introduce algorithms to extract high quality time-continuous affect annotations for the 12 videos from the noisy crowd annotations. We observe that, for the prediction of time-continuous affect annotations given low-level multimedia content, higher regression accuracies are achieved when the crowd sourced annotations are employed as labels than expert annotations. The study suggests that expensive expert annotations for large affective video corpora developments could be replaced by crowdsourcing annotation techniques.
Finally, we discuss opportunities for future applications of our research, and conclude with a summary of our contributions to the field of affective computin
Non-Symmetrized Hyperspherical Harmonics Method Applied to Light Hypernuclei
No full textThe present work is conducted in the field of few-body methods and it concerns the extension of the Non-Symmetrized Hyperspherical Harmonics method in order to treat quantum systems with different species of particles and additional degrees of freedom, like particle mixing. The aim is to introduce it as a new tool in the ab-initio study of light hypernuclei, and, more in general, of few-body quantum systems composed by a variety of different objects. To this end precise benchmark results for light hypernuclei with A=3-5 are provided and the perspectives of applications to systems with A>5 and the employment of the most recent hypernuclear interactions are discussed
Synthesis and characterization of Sol-Gel derived ZnO thin Films for memristive Applications
No full textThe sol-gel route is a versatile wet chemistry method suitable for the preparation of multi-layer thin films with defined thickness and surface roughness. In this thesis work, sol-gel derived undoped and doped ZnO multi-layers were prepared by spin coating technique on different substrates for a memristive application. The curing and annealing conditions for the ZnO films were adjusted based on the study performed on the ZnO xerogel powders, and taking into account the thermal stability of the engineered substrate used as a bottom electrode for the fabrication of the memristive building block. Chemical, structural and morphological features of the samples were investigated by complementary techniques including electron microscopy, Fourier transform infrared spectroscopy, micro-Raman, X-ray photoelectron spectroscopy and X-ray diffraction analysis. The combined characterization techniques assessed that uniform, dense and flawless films were obtained on the platinum substrate, i.e. the bottom electrode of the memristive cell. In particular, Al-doping was found to significantly affect the surface morphology, grain sizes and overall porosity of the films. According to the electrical measurements performed on undoped and Al-doped ZnO thin films sandwiched between Pt/Ti/SiO2 bottom electrode and different top electrodes including Ag and Pt-dishes, the selected fabrication conditions were suitable for fulfilling the requirements of active layers for the memristive development. The modification approach exploited toward the improvement of the memristive switching performances resulted in memristive responses with low compliance current in absence of electroforming steps. Furthermore, the resistance values at high resistance and low resistance states were reduced in the case of Al-doped films compared to the results obtained from undoped ZnO thin films
The Legal Education of Thomas Jefferson
No full textThomas Jefferson’s legal education offers a unique insight into the authoritative foundations of modern constitutionalism and sheds light on the revolutionary effort to digest American political experience according to the scientific legacy of Western jurisprudence.
Much attention has been dedicated by contemporary literature to the sources of Jefferson’s thought. However, the interpretations offered over the past fifty years have told us more about Jefferson’s political alignment, than of his comprehensive engagement with the many strands and several authorities the Western legal tradition.
The dissertation offers a study of Jefferson’s engagement with European jurisprudence. It tries, in particular, to connect Jefferson’s constitutionalism with medieval and early modern authorities addressing questions of sovereignty and religious freedom. These trans-Atlantic connections point equally to Common Law sources, as well to Continental Romano-Canonical jurisprudence and challenge, at the same time, the very distinction between the two traditions.
In selecting the sources, preference has been given to those that belonged to Jefferson’s personal library. And, amongst these, particular attention has been dedicated to the ones that bear Jefferson’s annotations or inscriptions.
The Introduction presents Jefferson’s copy of the foundational treatise on modern public law: Jean Bodin’s Les Six Livres de la Republique. Although Jefferson’s engagement with Bodin constitutes one of the main themes of the entire dissertation, the Introduction focuses mostly on the markings inscribed by Jefferson in his copy of the Republique and suggests that Jefferson may have been drawn to this work as it addressed the nature of power and of its constitutional limitations beyond any contingent concern.
The dissertation’s first part is then dedicated to the exploration of Jefferson’s doctrine on sovereignty. It assumes, as its starting point, Jefferson’s “Bartolist” doctrine on tyranny. The first chapter traces the development of this doctrine from the Middle Ages to Modernity. It also evaluates the force of its various arguments in Jefferson’s own historical understanding of the conditions that defined the struggle for independence as the rational outcome of a legal process. The second chapter investigates, instead, the legal titles placed by Jefferson at the origins of the Americans’ lawful acquisition of power – expatriation, conquest, and citizenship – and their connection to the European jurisprudence on the iura naturalia. The third
chapter closes the first part of the dissertation with an examination of Jefferson’s later reflections on the exercise of power. It focuses, in particular, on a two distinct groups of letters, dedicated to the independent exercise of sovereign power by each living generation, according to a Bodinian understanding of sovereignty, and to the constitutional relevance of intermediate bodies, maintained by Jefferson in keeping with Montesquieu.
The second part of the dissertation is dedicated to religious freedom. The fourth chapter provides an examination of Jefferson’s participation in the “Grotian moment” and illustrates his understanding of religion as the naturalized foundation of morality and jurisprudence. Moreover, it traces the enduring relevance of the distinction between spiritual and temporal jurisdictions within his thought. The fifth and final chapter, instead, focuses on Jefferson’s integrative jurisprudence and insists that the multiple dimensions of law remained a fundamental feature of Jefferson’s legal persuasion, as he strived to substantiate the checks on power through his continuous engagement with the legacy of Western jurisprudence
La testimonianza anonima nel processo penale. Un'analisi comparata.
Get PDFLa testimonianza anonima – intesa come la testimonianza resa da un soggetto con identità sconosciuta all’imputato – è un istituto che ha trovato, in tempi recenti, crescente diffusione in Europa. Ha trovato legittimazione anzitutto a Strasburgo, presso la Corte europea dei diritti dell’uomo. È principio ormai consolidato, nell’ambito della giurisprudenza della Corte europea, quello per cui l’uso di testimonianze anonime non è in tutti i casi incompatibile con i canoni dell’equo processo. Qualora sussista un rischio per l’incolumità della fonte di prova e siano attivate garanzie compensative a beneficio della difesa, l’impiego di dichiarazioni accusatorie provenienti da testimoni la cui identità sia secretata all’imputato non viola l’art. 6 C.e.d.u. Sulla scia di questa legittimazione “dall’alto”, molte legislazioni nazionali hanno introdotto modalità speciali di acquisizione della prova dichiarativa nei casi in cui sussista un pericolo per la sicurezza del testimone.
In questa direzione si è mosso anche il legislatore italiano. La legge n 136 del 2010 ha inserito, nel corpo dell’art. 497, il comma 2-bis, il quale impone agli agenti sotto copertura chiamati a riferire in dibattimento in ordine alle attività svolte sotto copertura, di declinare le generalità fittizie adottate nel corso delle investigazioni.
Si tratta di una disposizione che non ha avuto molta eco nel dibattito giuridico, eppure essa rappresenta una novità di grande rilievo, per almeno tre ragioni. In primo luogo, riflette una tendenza più generale, che attraversa ordinamenti stranieri e sovranazionali, volta a legittimare l’anonimato testimoniale in chiave di tutela delle fonti di prova. In secondo luogo, s’intreccia alle evoluzioni recenti in due settori nevralgici della procedura penale: da una parte, la tutela delle pregorative delle vittime e dei testimoni nell’ambito del processo; dall’altra, lo sviluppo delle tecniche “coperte” d’investigazione, ossia quella variegata fenomenologia di attività d’indagine che impongono, nel corso del loro svolgimento e nel processo celebrato sulla base dei risultati in esse acquisiti, condizioni di particolare segretezza dei funzionari coinvolti. Infine, la novella imprime una forte accelerazione e al tempo stesso innova, sotto molteplici aspetti, il dibattito sui rapporti tra fonti anonime e processo penale. Si rompe il dogma per cui al segreto sulla fonte di prova immancabilmente si associa l’irrilevanza delle informazioni rese. È oggi consentito l’uso a fini probatori di una conoscenza anche quando questa non è controllabile, sotto il profilo della provenienza, da ogni parte processuale.
Il punto di rottura non è di quelli che passano inosservati. Si spiega, così, il particolare taglio che si è voluto dare al lavoro. Si è scelto di concentrarsi, fra tutte le possibili manifestazioni dell’anonimo in campo processualpenalistico, sulla testimonianza anonima perché è attorno a tale figura probatoria che si coaugulano i più significativi tratti di novità che investono la materia e che si fa sentire più forte l’esigenza di un approfondimento sistematico
A digital simulation model of out-of-equilibrium market behaviour: a Keynesian-Sraffian approach
Get PDFKeynesian economics has devoted particular attention to out of full employment equilibrium phenomena, but the lack of an analytical framework for describing how economic agents interact and organize their production and consumption decisions has made it difficult to establish whether the economic system is self-adjusting at an out-of-full employment equilibrium.
One of the purposes of Sraffa's book Production of Commodities by Means of Commodities was to understand the conditions that allow the system to reproduce itself. But how trade takes place remains an open question. For Sraffian economics, the lack of an analytical framework for describing how economic agents interact and organize their production and consumption decisions, has made it difficult to consider out-of-equilibrium behaviour.
The present thesis is a first attempt to model Keynes's principle of effective demand with the aid of Sraffian schemes. The notion of effective demand requires the possibility for buyers and sellers to buy and sell thanks to the existence of newly generated or previously accumulated financial purchasing power. Stated differently, the very notion of out-of-equilibrium exchanges may require the emergence of new credit and debt relations.
Sraffa's original production schemes have been enriched with algorithmic behavioural functions that describe agent decisions and exchanges of property rights.
In the resulting algorithmic model of an economic system (with labour and goods market), decisions of production and consumption are made by a population of algorithmic rational agents (ARAs), divided between producers and workers. The ARAs are characterized by behavioural functions, specific trading rules, and are connected in a network. Exchanges are made by signing virtual contracts that involve the use of financial means. The creation of new financial means of exchange, credit and debt, is endogenous. Production is heterogeneous and conceived as a circular process.
The fundamental conclusion is that this digital economic laboratory has generated virtual economies able to converge towards production prices, uniform wage rates but non-uniform profit rates with an unequal distribution. The virtual economies result to be stable and efficient from a technological point of view despite economic policy can improve the performance of the whole economy.
The digital economic laboratory is a powerful instrument able to answer different research questions. It represents an answer to the need to develop models able to explore the complexity of out-of-equilibrium behaviour, grounded on bookkeeping principles and computable methods
Time-frequency reassignment for acoustic signal processing. From speech to singing voice applications
No full textThe various time-frequency (TF) representations of acoustic signals share the common objective to describe the temporal evolution of the spectral content of the signal, i.e., how the energy, or intensity, of the signal is changing in time. Many TF representations have been proposed in the past, and among them the short-time Fourier transform (STFT) is the one most commonly found in the core of acoustic signal processing techniques. However, certain problems that arise from the use of the STFT have been extensively discussed in the literature. These problems concern the unavoidable trade-off between the time and frequency resolution, and the fact that the selected resolution is fixed over the whole spectrum. In order to improve upon the spectrogram, several variations have been proposed over the time. One of these variations, stems from a promising method called reassignment. According to this method, the traditional spectrogram, as obtained from the STFT, is reassigned to a sharper representation called the Reassigned Spectrogram (RS). In this thesis we elaborate on approaches that utilize the RS as the TF representation of acoustic signals, and we exploit this representation in the context of different applications, as for instance speech recognition and melody extraction. The first contribution of this work is a method for speech parametrization, which results in a set of acoustic features called time-frequency reassigned cepstral coefficients (TFRCC). Experimental results show the ability of TFRCC features to present higher level characteristics of speech, a fact that leads to advantages in phone-level speech segmentation and speech recognition.
The second contribution is the use of the RS as the basis to extract objective quality measures, and in particular the reassigned cepstral distance and the reassigned point-wise distance. Both measures are used for channel selection (CS), following our proposal to perform objective quality measure based CS for improving the accuracy of speech recognition in a multi-microphone reverberant environment.
The final contribution of this work, is a method to detect harmonic pitch contours from singing voice signals, using a dominance weighting of the RS. This method has been exploited in the context of melody extraction from polyphonic music signals
Design and experimentation of communication and of a teaching sequence on atmospheric physics
No full textWeather and climate are topical issues widely present in the media, in the public culture, in political and socio-economic agendas and also in school guidelines. Having said that, confusion and a lot of misconceptions still exist with regards to issues such as climate change, greenhouse gases and the greenhouse effect, pollution, anthropogenic emissions, ozone hole, predictability of weather and climate, stationary processes, radiation fluxes and balances in the Earth system etc.
These themes are poorly addressed in the actual teaching practice in secondary schools, particularly from a quantitative point of view involving the underlying laws of physics, which are necessary for the understanding and construction of correct conceptual models of phenomena. Teachers often do not feel comfortable or lack the specific background for addressing such themes quantitatively, claiming for training initiatives which happen unfortunately only as a result of sporadic and local initiatives. For historical reasons, typical of the Italian context, these themes are usually addressed in subjects like geography or natural sciences for what concerns education in formal contexts such as primary and secondary schools and universities, but their treatment and significance would greatly benefit from an interdisciplinary approach, involving also the quantitative experimental approach of physics. At the same time, teaching physics from its general principles to their application in the context of weather phenomena and climate system, would improve the engagement and interest of students, fostering cooperation among teachers of different subjects, bridging boundaries and approaches characteristic of single disciplines. This would promote an integrated view of science as the result of a process, based on the application of the scientific method to the investigation and modeling of phenomena, where also technological advancement plays an important role, rather than as a mere collection of results and knowledge.
In this perspective the present work develops from the research in atmospheric physics, performed by the candidate during one year at Concordia station, Antarctica, presenting on one hand a series of physics communication initiatives designed and tested with innovative formats such as TEDx conferences, videoconferences with researchers working on the field, social platforms and traditional media, targeted to different audiences. On the other hand it presents the proposal of a teaching learning sequence based on quantitative experimental activities, demonstrations and simulations, targeted to secondary school students and pre-service teachers, integrating general physics with its applications to the atmosphere and to the climate system. The teaching learning sequence has been experimented with graduate students of the course: ''Experimental physics laboratory at high school I'', held at the Department of Physics of the University of Trento and in collaboration with IPRASE, it has been proposed in the form of a training course for physics and chemistry teachers and their technical assistants as a framework for the integration of physics and chemistry. The results of pre and post tests used as an evaluation tool of this preliminary experimentation will be presented, encouraging future developments of the sequence and further diffusion of weather and climate issues in the teaching practice through capillary pre-teachers' and teachers' training initiatives
Smartphone Data Transfer Protection According to Jurisdiction Regulations
No full textThe prevalence of mobile devices and their capability to access high speed Internet have transformed them into a portable pocket cloud interface. The sensitivity of a user’s personal data demands adequate level of protection in the cloud. In this regard, the European Union Data Protection regulations (e.g., article 25.1) restricts the transfer of European users’ personal data to certain locations. The matter of concern, however, is the enforcement of such regulations. Since cloud service provision is independent of physical location and data can travel to various servers, it is a challenging task to determine the location of data and enforce jurisdiction policies.
In this dissertation, first we demonstrate how mobile apps mishandle personal data collection and transfer by analyzing a wide range of popular Android apps in Europe. Then we investigate approaches to monitor and enforce the location restrictions of collected personal data. Since there are multiple entities such as mobile devices, mobile apps, data controllers and cloud providers in the process of collecting and transferring data, we study each one separately. We introduce design and prototyping of a suitable approach to perform or at least facilitate the enforcement procedure with respect to the duty of each entity.
Cloud service providers, provide their infrastructure to data controllers in form of virtual machines or containers; therefore, we design and implemented a tool, named VLOC, to verify the physical location of a virtual machine in cloud. Since VLOC requires the collaboration of the data controller, we design a framework, called DLOC, which enables the end users to determine the location of their data after being transferred to the cloud and probably replicated. DLOC is a distributed framework which does not need the data controller or cloud provider to participate or modify their systems; thus, it is economical to implement and to be used widely