Average-case analysis of power consumption in embedded systems

Power efficiency is one of the most important constraints in the design of embedded systems since such systems are generally driven by batteries with limited energy budget or restricted power supply. In every embedded system, there are one or more processor cores to run the software and interact with the other hardware components of the system. The power consumption of the processor core(s) has an important impact on the total power dissipated in the system. Hence, the processor power optimization is crucial in satisfying the power consumption constraints, and developing low-power embedded systems. A key aspect of research in processor power optimization and management is “power estimation”. Having a fast and accurate method for processor power estimation at design time helps the designer to explore a large space of design possibilities, to make the optimal choices for developing a power efficient processor. Likewise, understanding the processor power dissipation behaviour of a specific software/application is the key for choosing appropriate algorithms in order to write power efficient software. Simulation-based methods for measuring the processor power achieve very high accuracy, but are available only late in the design process, and are often quite slow. Therefore, the need has arisen for faster, higher-level power prediction methods that allow the system designer to explore many alternatives for developing powerefficient hardware and software. The aim of this thesis is to present fast and high-level power models for the prediction of processor power consumption. Power predictability in this work is achieved in two ways: first, using a design method to develop power predictable circuits; second, analysing the power of the functions in the code which repeat during execution, then building the power model based on average number of repetitions. In the first case, a design method called Asynchronous Charge Sharing Logic (ACSL) is used to implement the Arithmetic Logic Unit (ALU) for the 8051 microcontroller. The ACSL circuits are power predictable due to the independency of their power consumption to the input data. Based on this property, a fast prediction method is presented to estimate the power of ALU by analysing the software program, and extracting the number of ALU-related instructions. This method achieves less than 1% error in power estimation and more than 100 times speedup in comparison to conventional simulation-based methods. In the second case, an average-case processor energy model is developed for the Insertion sort algorithm based on the number of comparisons that take place in the execution of the algorithm. The average number of comparisons is calculated using a high level methodology called MOdular Quantitative Analysis (MOQA). The parameters of the energy model are measured for the LEON3 processor core, but the model is general and can be used for any processor. The model has been validated through the power measurement experiments, and offers high accuracy and orders of magnitude speedup over the simulation-based method.

Analyse quantitative de la carrière criminelle des internautes effectuant du leurre d’enfants

Objectifs: L’objectif principal de ce mémoire consiste à comprendre les caractéristiques des carrières criminelles d’individus connus de la police pour avoir perpétré une infraction de leurre d’enfants sur Internet. Aussi, par une analyse typologique à l’aide des antécédents criminels, il sera possible d’établir une typologie d’individus ayant leurré des enfants sur Internet. Également, il sera question de vérifier s’il y a un lien entre les caractéristiques des antécédents criminels de ces individus sur la perpétration de l’agression sexuelle hors ligne. Méthodologie: Provenant de données officielles de la communauté policière du Québec, l’échantillon comprend les parcours de criminels ayant perpétré une infraction de leurre d’enfants sur Internet. Des analyses descriptives en lien avec les différents paramètres de la carrière criminelle seront effectuées. Ensuite, des tests de moyenne et une analyse de régression Cox permettront de vérifier la présence ou non d’un lien statistique entre les caractéristiques des antécédents criminels des individus connus de la police pour leurre d’enfants sur Internet et le passage à l’acte physique. Résultats: Les analyses ont montré que la majorité des sujets n’avaient aucun antécédent judiciaire. Pour la plupart, le leurre d’enfants est le crime le plus grave perpétré au cours de leur carrière criminelle. Trois catégories d’individus ont été décelées : les amateurs, les spécialistes et les généralistes. Ce sont les individus polymorphes ayant une carrière criminelle plus grave et plus longue qui sont portés à agresser sexuellement avant le leurre. Cependant, ce sont des individus spécialisés ayant une importante proportion de délits sexuels dans leurs antécédents criminels qui ont plus de chance d’agresser sexuellement suite à l’exploitation sexuelle sur Internet.

The influence of actions on auditory perception: cognitive and neural mechanisms

It is well known that self-generated stimuli are processed differently from externally generated stimuli. For example, many people have noticed since childhood that it is very difficult to make a self-tickling. In the auditory domain, self-generated sounds elicit smaller brain responses as compared to externally generated sounds, known as the sensory attenuation (SA) effect. SA is manifested in reduced amplitudes of evoked responses as measured through MEEG, decreased firing rates of neurons and a lower level of perceived loudness for self-generated sounds. The predominant explanation for SA is based on the idea that self-generated stimuli are predicted (e.g., the forward model account). It is the nature of their predictability that is crucial for SA. On the contrary, the sensory gating account emphasizes a general suppressive effect of actions on sensory processing, regardless of the predictability of the stimuli. Both accounts have received empirical support, which suggests that both mechanisms may exist. In chapter 2, three behavioural studies concerning the influence of motor activation on auditory perception were presented. Study 1 compared the effect of SA and attention in an auditory detection task and showed that SA was present even when substantial attention was paid to unpredictable stimuli. Study 2 compared the loudness perception of tones generated by others between Chinese and British participants. Compared to externally generated tones, a decrease in perceived loudness for others generated tones was found among Chinese but not among the British. In study 3, partial evidence was found that even when reading words that are related to action, auditory detection performance was impaired. In chapter 3, the classic SA effect of M100 suppression was replicated with MEG in study 4. With time-frequency analysis, a potential neural information processing sequence was found in auditory cortex. Prior to the onset of self-generated tones, there was an increase of oscillatory power in the alpha band. After the stimulus onset, reduced gamma power and alpha/beta phase locking were found. The three temporally segregated oscillatory events correlated with each other and with SA effect, which may be the underlying neural implementation of SA. In chapter 4, a TMS-MEG study was presented investigating the role of the cerebellum in adapting to delayed presentation of self-generated tones (study 5). It demonstrated that in sham stimulation condition, the brain can adapt to the delay (about 100 ms) within 300 trials of learning by showing a significant increase of SA effect in the suppression of M100, but not M200 component. Whereas after stimulating the cerebellum with a suppressive TMS protocol, the adaptation in M100 suppression disappeared and the pattern of M200 suppression reversed to M200 enhancement. These data support the idea that the suppressive effect of actions on auditory processing is a consequence of both motor driven sensory predictions and general sensory gating. The results also demonstrate the importance of neural oscillations in implementing SA effect and the critical role of the cerebellum in learning sensory predictions under sensory perturbation.

Il principio di prevedibilità in materia penale. Riflessi sulle garanzie fondamentali di una analisi comparata sulla "cultura del precedente"

Nell’epoca di profonda transizione dell’era «pos-moderna», il modello tradizionale di legalità che conferisce al Parlamento il monopolio in materia penale entra in crisi in ragione della frammentazione delle fonti del diritto - a livello nazionale e sovranazionale - nonché delle spinte di globalizzazione capaci di incidere, ormai, ben oltre il mero piano economico. A fronte della incapacità del legislatore di rispondere in termini effettivi alla urgenza di razionalizzare e riformare il sistema penale, quindi, il potere giudiziario ha assunto una funzione di sostanziale supplenza, generando inevitabili attriti con il nullum crimen e i suoi corollari. Ne deriva che il Giudice di legittimità sempre più si preoccupa di assicurare la prevedibilità dei mutamenti interpretativi, specie se in malam partem, tenendo a mente gli ultimi approdi della giurisprudenza di Strasburgo in riferimento all’art. 7 CEDU. In particolare, tanto nelle motivazioni delle decisioni quanto nei contributi dottrinali, si diffonde graduale il riferimento a istituti propri del modello di common law: la recente riforma dell’art. 618, co 1 bis, c.p.p., del resto, è stata descritta a più voci come l’avvio della diffusione nell’ordinamento interno della c.d. “cultura del precedente”. In tale frangente, diviene utile approfondire l’opportunità dell’accostamento tra il modello di common law e di civil law, conducendo uno studio comparato tra i due ordinamenti quanto all’esercizio del potere punitivo che intende esaminare l’opportunità di acquisire rimedi propri della esperienza secolare del diritto judge-made in un ordinamento governato dalla soggezione del giudice alla legge.

Lavorare il tempo. I diritti del prestatore tra tecnica e società

La dimensione giuridica del tempo, cioè il ruolo del tempo nel diritto, ha contribuito a far emergere il lavoro quale concetto legale astratto dal prestatore, funzionale alla sua alienazione. Rompere l’unitarietà del tempo della persona, per consacrarne una parte al lavoro, ha dato ai rapporti di potere tra gli individui una forma giuridica in grado di legittimarli. Il primo capitolo si sofferma sulla costruzione legale del lavoro subordinato attraverso la definizione del suo tempo. Tra gli elementi essenziali del contratto tipizzato dall’art. 2094 c.c., il tempo nella causa, oltre a mostrare la non istantaneità dello scambio e la indeterminatezza del regolamento contrattuale, non assurge a criterio discretivo dalle collaborazioni o dal lavoro autonomo. Se dalla causa si passa ad indagare l’oggetto, l’interprete si imbatte nel pudore di svelare quale sia il vero elemento su cui incide il contratto, la persona del lavoratore, che induce a prediligere la finzione di allontanare l’attività dal corpo di chi la produce: l’orario è la tecnica giuridica che rende possibile la partecipazione del lavoro ad una logica di scambio. Il secondo e il terzo capitolo si concentrano sulla regolazione e interpretazione del tempo di lavoro in chiave diacronica. La legislazione lavoristica ha trovato i propri albori nella disciplina eteronoma dell’orario, come strumento per tutelare i prestatori dagli eccessi mercantilistici. L’attuale quadro normativo è molto attento alle ragioni creditorie ma la giurisprudenza della Corte di giustizia testimonia l’irrequietudine di una materia viva e in movimento. Non è un caso che il legislatore europeo, nei piccoli passi compiuti per rafforzare il diritto sociale comune agli Stati membri, abbia assegnato al tempo un ruolo centrale, come prevedibilità delle condizioni di lavoro (direttiva n. 1152 del 2019), come equilibrio tra attività professionale e vita familiare (direttiva n. 1158 del 2019) e un domani, forse, come diritto alla disconnessione.

Sustainable exploitation of offshore renewable energy sources

Energy transition is the response of humankind to the concerning effects of fossil fuels depletion, climate change and energy insecurity, and calls for a deep penetration of renewable energy sources (RESs) in power systems and industrial processes. Despite the high potentials, low impacts and long-term availability, RESs present some limits which need to be overcome, such as the strong variability and difficult predictability, which result in scarce reliability and difficult applicability in steady-state processes. Some technological solutions relate to energy storage systems, equipment electrification and hybrid systems deployment, thus accomplishing distributed generation even in remote sites as offshore. However, all of these actions cannot disregard sustainability, which represents a founding principle for any project, bringing together economics, reliability and environmental protection. To entail sustainability in RESs-based innovative projects, previous knowledge and tools are often not tailored or miss the novel objectives. This research proposes three methodological approaches, bridging the gaps. The first contribute adapts literature-based indicators of inherent safety and energy efficiency to capture the specificities of novel process plants and hybrid systems. Minor case studies dealing with novel P2X processes exemplify the application of these novel indicators. The second method guides the conceptual design of hybrid systems for the valorisation of a RES in a site, by considering the sustainability performances of alternative design options. Its application is demonstrated through the comparison of two offshore sites where wave energy can be valorised. Finally, “OHRES”, a comprehensive tool for the sustainable optimisation of hybrid renewable energy systems is proposed. “OHRES” hinges on the exploitation of multiple RESs, by converting ex-post sustainability indicators into discrimination markers screening a large number of possible system configurations, according to the location features. Five case studies demonstrate “OHRES” versatility in the sustainable valorisation of multiple RESs.