6 resultados para 080602 Computer-Human Interaction

em AMS Tesi di Dottorato - Alm@DL - Università di Bologna


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This thesis analyses problems related to the applicability, in business environments, of Process Mining tools and techniques. The first contribution is a presentation of the state of the art of Process Mining and a characterization of companies, in terms of their "process awareness". The work continues identifying circumstance where problems can emerge: data preparation; actual mining; and results interpretation. Other problems are the configuration of parameters by not-expert users and computational complexity. We concentrate on two possible scenarios: "batch" and "on-line" Process Mining. Concerning the batch Process Mining, we first investigated the data preparation problem and we proposed a solution for the identification of the "case-ids" whenever this field is not explicitly indicated. After that, we concentrated on problems at mining time and we propose the generalization of a well-known control-flow discovery algorithm in order to exploit non instantaneous events. The usage of interval-based recording leads to an important improvement of performance. Later on, we report our work on the parameters configuration for not-expert users. We present two approaches to select the "best" parameters configuration: one is completely autonomous; the other requires human interaction to navigate a hierarchy of candidate models. Concerning the data interpretation and results evaluation, we propose two metrics: a model-to-model and a model-to-log. Finally, we present an automatic approach for the extension of a control-flow model with social information, in order to simplify the analysis of these perspectives. The second part of this thesis deals with control-flow discovery algorithms in on-line settings. We propose a formal definition of the problem, and two baseline approaches. The actual mining algorithms proposed are two: the first is the adaptation, to the control-flow discovery problem, of a frequency counting algorithm; the second constitutes a framework of models which can be used for different kinds of streams (stationary versus evolving).

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Nell'ambito delle teorie dello sviluppo, un filone di studi, originato dai lavori di North (1973) e consolidatosi negli ultimi anni, individua nelle istituzioni, definite come le regole del gioco o i vincoli disegnati dagli uomini per disciplinare i loro rapporti, i fattori fondamentali dello sviluppo economico. Le istituzioni, nel modello elaborato da Acemoglu, Johnson e Robinson (2004), sono il frutto di interazioni dinamiche tra potere politico de jure, determinato dalle istituzioni politiche, e potere politico de facto, determinato dalla distribuzione delle risorse economiche. Sulla base di questa prospettiva teorica, questa tesi propone uno studio di carattere quantitativo sulla qualità istituzionale, la traduzione operativa del concetto di istituzioni, composta dalle tre fondamentali dimensioni di democrazia, efficienza ed efficacia del governo e assenza di corruzione. La prima parte, che analizza sistematicamente pro e contro di ciascuna tipologia di indicatori, è dedicata alla revisione delle misure quantitative di qualità istituzionale, e individua nei Worldwide Governance Indicators la misura più solida e consistente. Questi indici sono quindi utilizzati nella seconda parte, dove si propone un'analisi empirica sulle determinanti della qualità istituzionale. Le stime del modello di regressione cross-country evidenziano che la qualità istituzionale è influenzata da alcuni fattori prevalentemente esogeni come la geografia, la disponibilità di risorse naturali e altre caratteristiche storiche e culturali, insieme ad altri fattori di carattere più endogeno. In quest'ultima categoria, i risultati evidenziano un effetto positivo del livello di sviluppo economico, mentre la disuguaglianza economica mostra un impatto negativo su ciascuna delle tre dimensioni di qualità istituzionale, in particolare sulla corruzione. Questi risultati supportano la prospettiva teorica e suggeriscono che azioni di policy orientate alla riduzione delle disparità sono capaci di generare sviluppo rafforzando la democrazia, migliorando l'efficienza complessiva del sistema economico e riducendo i livelli di corruzione.

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Healthcare, Human Computer Interfaces (HCI), Security and Biometry are the most promising application scenario directly involved in the Body Area Networks (BANs) evolution. Both wearable devices and sensors directly integrated in garments envision a word in which each of us is supervised by an invisible assistant monitoring our health and daily-life activities. New opportunities are enabled because improvements in sensors miniaturization and transmission efficiency of the wireless protocols, that achieved the integration of high computational power aboard independent, energy-autonomous, small form factor devices. Application’s purposes are various: (I) data collection to achieve off-line knowledge discovery; (II) user notification of his/her activities or in case a danger occurs; (III) biofeedback rehabilitation; (IV) remote alarm activation in case the subject need assistance; (V) introduction of a more natural interaction with the surrounding computerized environment; (VI) users identification by physiological or behavioral characteristics. Telemedicine and mHealth [1] are two of the leading concepts directly related to healthcare. The capability to borne unobtrusiveness objects supports users’ autonomy. A new sense of freedom is shown to the user, not only supported by a psychological help but a real safety improvement. Furthermore, medical community aims the introduction of new devices to innovate patient treatments. In particular, the extension of the ambulatory analysis in the real life scenario by proving continuous acquisition. The wide diffusion of emerging wellness portable equipment extended the usability of wearable devices also for fitness and training by monitoring user performance on the working task. The learning of the right execution techniques related to work, sport, music can be supported by an electronic trainer furnishing the adequate aid. HCIs made real the concept of Ubiquitous, Pervasive Computing and Calm Technology introduced in the 1988 by Marc Weiser and John Seeley Brown. They promotes the creation of pervasive environments, enhancing the human experience. Context aware, adaptive and proactive environments serve and help people by becoming sensitive and reactive to their presence, since electronics is ubiquitous and deployed everywhere. In this thesis we pay attention to the integration of all the aspects involved in a BAN development. Starting from the choice of sensors we design the node, configure the radio network, implement real-time data analysis and provide a feedback to the user. We present algorithms to be implemented in wearable assistant for posture and gait analysis and to provide assistance on different walking conditions, preventing falls. Our aim, expressed by the idea to contribute at the development of a non proprietary solutions, driven us to integrate commercial and standard solutions in our devices. We use sensors available on the market and avoided to design specialized sensors in ASIC technologies. We employ standard radio protocol and open source projects when it was achieved. The specific contributions of the PhD research activities are presented and discussed in the following. • We have designed and build several wireless sensor node providing both sensing and actuator capability making the focus on the flexibility, small form factor and low power consumption. The key idea was to develop a simple and general purpose architecture for rapid analysis, prototyping and deployment of BAN solutions. Two different sensing units are integrated: kinematic (3D accelerometer and 3D gyroscopes) and kinetic (foot-floor contact pressure forces). Two kind of feedbacks were implemented: audio and vibrotactile. • Since the system built is a suitable platform for testing and measuring the features and the constraints of a sensor network (radio communication, network protocols, power consumption and autonomy), we made a comparison between Bluetooth and ZigBee performance in terms of throughput and energy efficiency. Test in the field evaluate the usability in the fall detection scenario. • To prove the flexibility of the architecture designed, we have implemented a wearable system for human posture rehabilitation. The application was developed in conjunction with biomedical engineers who provided the audio-algorithms to furnish a biofeedback to the user about his/her stability. • We explored off-line gait analysis of collected data, developing an algorithm to detect foot inclination in the sagittal plane, during walk. • In collaboration with the Wearable Lab – ETH, Zurich, we developed an algorithm to monitor the user during several walking condition where the user carry a load. The remainder of the thesis is organized as follows. Chapter I gives an overview about Body Area Networks (BANs), illustrating the relevant features of this technology and the key challenges still open. It concludes with a short list of the real solutions and prototypes proposed by academic research and manufacturers. The domain of the posture and gait analysis, the methodologies, and the technologies used to provide real-time feedback on detected events, are illustrated in Chapter II. The Chapter III and IV, respectively, shown BANs developed with the purpose to detect fall and monitor the gait taking advantage by two inertial measurement unit and baropodometric insoles. Chapter V reports an audio-biofeedback system to improve balance on the information provided by the use centre of mass. A walking assistant based on the KNN classifier to detect walking alteration on load carriage, is described in Chapter VI.

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Bifidobacterium is an important genus of the human gastrointestinal microbiota, affecting several host physiological features. Despite the numerous Bifidobacterium related health-promoting activities, there is still a dearth of information about the molecular mechanisms at the basis of the interaction between this microorganism and the host. Bacterial surface associated proteins may play an important role in this interaction because of their ability to intervene with host molecules, as recently reported for the host protein plasminogen. Plasminogen is the zymogen of the trypsin-like serine protease plasmin, an enzyme with a broad substrate specificity. Aim of this thesis is to deepen the knowledge about the interaction between Bifidobacterium and the human plasminogen system and its role in the Bifidobacterium-host interaction process. As a bifidobacterial model, B. animalis subsp. lactis BI07 has been used because of its large usage in dairy and pharmaceutical preparations. We started from the molecular characterization of the interaction between plasminogen and one bifidobacterial plasminogen receptor, DnaK, a cell wall protein showing high affinity for plasminogen, and went on with the study of the impact of intestinal environmental factors, such as bile salts and inflammation, on the plasminogen-mediated Bifidobacterium-host interaction. According to our in vitro findings, by enhancing the activation of the bifidobacterial bound plasminogen to plasmin, the host inflammatory response results in the decrease of the bifidobacterial adhesion to the host enterocytes, favouring bacterial migration to the luminal compartment. Conversely, in the absence of inflammation, plasminogen acts as a molecular bridge between host enterocytes and bifidobacteria, enhancing Bifidobacterium adhesion. Furthermore, adaptation to physiological concentrations of bile salts enhances the capability of this microorganism to interact with the host plasminogen system. The host plasminogen system thus represents an important and flexible tool used by bifidobacteria in the cross-talk with the host.

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Mainstream hardware is becoming parallel, heterogeneous, and distributed on every desk, every home and in every pocket. As a consequence, in the last years software is having an epochal turn toward concurrency, distribution, interaction which is pushed by the evolution of hardware architectures and the growing of network availability. This calls for introducing further abstraction layers on top of those provided by classical mainstream programming paradigms, to tackle more effectively the new complexities that developers have to face in everyday programming. A convergence it is recognizable in the mainstream toward the adoption of the actor paradigm as a mean to unite object-oriented programming and concurrency. Nevertheless, we argue that the actor paradigm can only be considered a good starting point to provide a more comprehensive response to such a fundamental and radical change in software development. Accordingly, the main objective of this thesis is to propose Agent-Oriented Programming (AOP) as a high-level general purpose programming paradigm, natural evolution of actors and objects, introducing a further level of human-inspired concepts for programming software systems, meant to simplify the design and programming of concurrent, distributed, reactive/interactive programs. To this end, in the dissertation first we construct the required background by studying the state-of-the-art of both actor-oriented and agent-oriented programming, and then we focus on the engineering of integrated programming technologies for developing agent-based systems in their classical application domains: artificial intelligence and distributed artificial intelligence. Then, we shift the perspective moving from the development of intelligent software systems, toward general purpose software development. Using the expertise maturated during the phase of background construction, we introduce a general-purpose programming language named simpAL, which founds its roots on general principles and practices of software development, and at the same time provides an agent-oriented level of abstraction for the engineering of general purpose software systems.

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The monitoring of cognitive functions aims at gaining information about the current cognitive state of the user by decoding brain signals. In recent years, this approach allowed to acquire valuable information about the cognitive aspects regarding the interaction of humans with external world. From this consideration, researchers started to consider passive application of brain–computer interface (BCI) in order to provide a novel input modality for technical systems solely based on brain activity. The objective of this thesis is to demonstrate how the passive Brain Computer Interfaces (BCIs) applications can be used to assess the mental states of the users, in order to improve the human machine interaction. Two main studies has been proposed. The first one allows to investigate whatever the Event Related Potentials (ERPs) morphological variations can be used to predict the users’ mental states (e.g. attentional resources, mental workload) during different reactive BCI tasks (e.g. P300-based BCIs), and if these information can predict the subjects’ performance in performing the tasks. In the second study, a passive BCI system able to online estimate the mental workload of the user by relying on the combination of the EEG and the ECG biosignals has been proposed. The latter study has been performed by simulating an operative scenario, in which the occurrence of errors or lack of performance could have significant consequences. The results showed that the proposed system is able to estimate online the mental workload of the subjects discriminating three different difficulty level of the tasks ensuring a high reliability.