Autonomous Vehicles (AVs) should result in tremendous benefits to safe human transportation. Recent reports indicate a global average of 3,287 road crash related fatalities a day with the blame, in most cases, assigned to the human driver. By replacing the main cause, AVs are predicted to significantly reduce road accidents -- some claiming up to a 90% reduction on US roads. However, achieving these numbers is not simple. AVs are expected to assume tasks that human drivers perform both consciously and unconsciously -- in some instances, with Machine Learning. AVs incur new levels of complexity that, if handled incorrectly, can result in failures that cause loss of human life and damage to the environment. Accidents involving SAE Level 2 vehicles have highlighted such failures and demonstrated that AVs have a long way to go. The path towards safe AVs includes system architectures that provide effective failure monitoring, detection and mitigation. These architectures must produce AVs that degrade gracefully and remain sufficiently operational in the presence of failures. We introduce Safe-AV, a fault tolerant safety architecture for AVs that is based on the commonly adopted E-Gas 3 Level Monitoring Concept, the Simplex Architecture and guided by a thorough hazard analysis in the form of Systems-Theoretic Process Analysis (STPA). We commenced the architecture design with a review of some modern AV accidents which helped identify the types of failures AVs can present and acted as a first step to our STPA. The hazard analysis was applied to an initial AV architecture (without safety mechanisms) consisting of components that should be present in a typical AV (based on the literature and our ideas). Our STPA identified the system level accidents, hazards and corresponding loss scenarios that led to well-founded safety requirements which, in turn, evolved the initial architecture into Safe-AV. / Thesis / Master of Applied Science (MASc)

We investigate the extraction of cryptographic keying material from nano-scale variations of digital circuit outputs by using nested polar codes and neural leakage estimators. A runtime-efficient algorithm is developed to simulate such a system. A certain family of digital circuit outputs are known to be a source of randomness that can be used as a unique identifier for each output. By generating secret keys from these unique outputs, one can apply cryptographic methods by using the secret keys as the seed. One is required to store extra helper data generated first time the outputs are measured, since there is noise in digital circuit outputs, to be able to reconstruct the same key from every measurement of the same digital circuit. The generation of the secret keys and helper data follow a nested polar code construction, and they are generated in this thesis to estimate the Shannon entropy of the secret key and secrecy leakage to a passive attacker using neural networks. The estimators used illustrate, for the first time, that the system generates secret keys of almost maximum entropy and negligible secrecy leakage for practical cryptographic systems if the digital circuit outputs can be preprocessed to obtain almost independent and identically distributed (i.i.d.) random outputs distributed according to a binary uniform distribution. The algorithm design is evaluated and improvements for lower runtime are suggested. Ideas for future research are presented.

Habitat modeling can assist in managing potentially widespread but poorly known biological resources such as the federally endangered Delmarva fox squirrel (DFS; Sciurus niger cinereus). The ability to predict or identify suitable habitat is a necessary component of this species' recovery. Habitat identification is also an important consideration when evaluating impacts of land development on this species distribution, which is limited to the Delmarva Peninsula. The goal of this study was to build a predictive model of DFS occurrence that can be used towards the effective management of this species. I developed 5 a'priori global models to predict DFS occurrence based on literature review, past models, and professional experience. I used infrared photomonitors to document habitat use of Delmarva fox squirrels at 27 of 86 sites in the southern Maryland portion of the Delmarva Peninsula. All data were collected on the U.S. Fish and Wildlife Service Chesapeake Marshlands National Wildlife Refuge in Dorchester County, Maryland. Preliminary analyses of 27 DFS present (P) and 59 DFS absent (A) sites suggested that DFS use in my study area was significantly (Wilcoxon Mann-Whitney, P < 0.10) correlated with tree stems > 50 cm dbh/ha (Pmean = 16 + 3.8, Amean = 8+ 2.2), tree stems > 40 cm dbh/ha (Pmean = 49 + 8.1, Amean = 33 + 5.5), understory height (Pmean = 11 m + 0.8, Amean = 9 m + 0.5), overstory canopy height (Pmean = 31 m + 0.6, Amean = 28 m + 0.6), percent overstory cover (Pmean = 82 + 3.9, Amean = 73 + 3.1), shrub stems/ha (Pmean = 8068 + 3218, Amean = 11,119 + 2189), and distance from agricultural fields (Pmean = 964 m + 10, Amean = 1308 m + 103). Chi-square analysis indicated a correlation with shrub evenness (observed on 7% of DFS present sites and 21% of DFS absent sites). Using logistic regression and the Information Theoretic approach, I developed 7 model sets (5 a priori and 2 post hoc) to predict the probability of Delmarva fox squirrel habitat use as a function of micro- and macro-habitat characteristics. Of over 200 total model arrays tested, the model that fit the statistical, biological, and pragmatic criteria postulated was a post hoc integrated model: DFS use = percent overstory cover + shrub evenness + overstory canopy height. This model was determined to be the best of its subset (wi = 0.54), had a high percent concordance (>75%), a significant likelihood ratio (P = 0.0015), and the lowest AICc value (98.3) observed. Employing this predictive model of Delmarva fox squirrel occurrence can benefit recovery and consultation processes by facilitating systematic rangewide survey efforts and simplifying site screenings. / Master of Science

The movement or flow of employees into, around and out of organisations (‘employee flow’) has long been a central issue in human resource management and industrial psychology. This is especially so for the specific element of employee turnover, but also applies to staffing and internal talent development. Employee flow is especially salient in a South African context characterised by scarce skills. The voluminous literature on employee flow has tended to view each element such as recruitment or turnover separately, and has generally focused on internal outcomes (e.g. commitment or satisfaction). This thesis attempts to add two crucial features, namely EF as a whole system (i.e. inflows, intraorganisation flows and outflows of staff in conjunction), and customer-based outcomes. Something of a synthesis is thus sought between EF and ideas of marketing productivity. Marketing productivity has been proposed as one of the most important foci of the marketing discipline (Rust, Ambler, Carpenter, Kumar, & Srivastava, 2004; Sheth & Sisodia, 2002). It refers to links between marketing and organisational performance or value. Models such as the ‘service profit chain’ (Heskett, Sasser & Schlesinger, 1997) identify the antecedents of marketing productivity to be internal organisation characteristics such as staff satisfaction or loyalty. This thesis seeks to expand such models in the context of a system of EFs. Advanced decision theoretic utility theories of EF (e.g. Boudreau & Berger, 1985) allow for the complete, integrated value of employee movements over time to be modelled. Such a model is constructed and links to marketing metrics, notably service perceptions, investigated. Organisational value arising via the outcomes for customers are further investigated. Thus increased value of employee movements is proposed to generate organisational value, mediated by improved customer equity (e.g. Gelade & Young, 2005). An empirical, survey-based study was conducted to assess the model. EF was assessed in business-to-business relationships from the perspective of the customer using conceptions of decision theoretic utility analysis, and both intermediate and outcome-based customer perceptions of service quality used as dependent variables. Moderation effects from frequency of interaction and integration of the customer into the supply chain were also tested, as well as controls for characteristics of the transaction, organisation and industry. Results suggest that EF does significantly affect various stages of service quality provision, notably ‘potential quality’, which it appears mediates links to other aspects of service provision, especially final service outcomes. In addition, EF was also found to affect outcomes through the intermediate relational element of 'soft process quality', possibly highlighting the importance of relationship management and soft skills in B2B relationships. Employee outflows in particular showed evidence of relatively strong effects, possibly highlighting the ongoing salience of turnover, in particular effective identification and management of functional versus dysfunctional turnover instead of a sole focus on retention. Results were significantly stronger for service industries than others (presumably as service is the outcome), and when there were relatively few supplier contact staff (perhaps due to social networking, bonding, exchange or emotional contagion). This thesis adds substantially to the methodologies underlying service profit chain models. It explicitly included new constructs (EF utility). Contextually, it was the first proper test of this model in South Africa. Theoretical contributions arose from new inter-disciplinary syntheses of utility models, finally linking employee and customer utilities to the organisation. Ultimately, practical significance may arise for managerial models, estimating and justifying human resource interventions.

La thèse est dédiée à l'analyse et à la conception de la commande tolérante aux défauts (fault tolerant control - FTC) en se fondant sur des méthodes ensemblistes. Nous étudions l'apparition des défauts pour les systèmes multi-capteurs, et les modes de détection, ainsi que la conception de lois de commande qui assurent la stabilité en boucle fermée. L'utilisation des ensembles invariants/contractifs permet la caractérisation des signaux résiduels, qui sont utilisés par la suite dans le processus de détection et d'isolement des défauts. La décision est fondée sur le positionnement par rapport à des hyperplans de séparation avec des importantes réductions de temps de calcul. Un mécanisme dual mis en œuvre par un bloc de récupération, permet la certification de la récupération des capteurs précédemment affectés par ces défauts.Dans une perspective théorique, nous soulignons les conditions qui permettent l'inclusion du bloc FDI (fault detection and isolation) et sa raison d'être dans la conception des lois de commande. Cela conduit par exemple à la synthèse des gains de retour d'état statique, par résolution de problèmes d'optimisation efficace (linéaire/convexe).Selon les paramètres choisis pour le réglage, la conception de la FTC peut être complétée par un superviseur de référence ou d'une loi de commande prédictive, qui adapte la trajectoire d'état et l'action de commande par retour d'état, afin d'assurer l'identification et la détection des défauts. Les questions spécifiques à l'utilisation de méthodes ensemblistes sont détaillées et des améliorations diverses sont proposées, par exemple : la construction des ensembles invariants, des formulations moins complexes des problèmes de type Mixed Integer Programming (MIP), l'analyse de la stabilité des systèmes commutés (notion de ``dwell-time''). / The scope of the thesis is the analysis and design of fault tolerant control (FTC) schemes through the use of set-theoretic methods. In the framework of multisensor schemes, the faults appearance and the modalities to accurately detect them are investigated as well as the design of control laws which assure the closed-loop stability. By using invariant/contractive sets to describe the residual signals, a fault detection and isolation (FDI) mechanism with reduced computational demands is implemented based on set-separation. A dual mechanism, implemented by a recovery block, which certificates previously fault-affected sensors is also studied. From a broader theoretical perspective, we point to the conditions which allow the inclusion of {FDI} objectives in the control law design. This leads to static feedback gains synthesis by means of numerically attractive optimization problems. Depending on the parameters selected for tuning, is shown that the FTC design can be completed by a reference governor or a predictive control scheme which adapts the state trajectory and the feedback control action in order to assure {FDI}. When necessary, the specific issues originated by the use of set-theoretic methods are detailed and various improvements are proposed towards: invariant set construction, mixed integer programming (MIP), stability for switched systems (dwell-time notions).

L'objectif de cette thèse est de proposer des solutions aux problèmes liés à la commande optimale de systèmes dynamiques multi-agents en présence de contraintes. Des éléments de la théorie de commande et d'optimisation sont appliqués à différents problèmes impliquant des formations de systèmes multi-agents. La thèse examine le cas d'agents soumis à des contraintes dynamiques. Pour faire face à ces problèmes, les concepts bien établis tels que la théorie des ensembles, la platitude différentielle, la commande prédictive (Model Predictive Control - MPC), la programmation mixte en nombres entiers (Mixed-Integer Programming - MIP) sont adaptés et améliorés. En utilisant ces notions théoriques, ce travail de thèse a porté sur les propriétés géométriques de la formation d'un groupe multi-agents et propose un cadre de synthèse original qui exploite cette structure. En particulier, le problème de conception de formation et les conditions d'évitement des collisions sont formulés comme des problèmes géométriques et d'optimisation pour lesquels il existe des procédures de résolution. En outre, des progrès considérables dans ce sens ont été obtenus en utilisant de façon efficace les techniques MIP (dans le but d'en déduire une description efficace des propriétés de non convexité et de non connexion d'une région de faisabilité résultant d'une collision de type multi-agents avec des contraintes d'évitement d'obstacles) et des propriétés de stabilité (afin d'analyser l'unicité et l'existence de configurations de formation de systèmes multi-agents). Enfin, certains résultats théoriques obtenus ont été appliqués dans un cas pratique très intéressant. On utilise une nouvelle combinaison de la commande prédictive et de platitude différentielle (pour la génération de référence) dans la commande et la navigation de véhicules aériens sans pilote (UAVs). / The goal of this thesis is to propose solutions for the optimal control of multi-agent dynamical systems under constraints. Elements from control theory and optimization are merged together in order to provide useful tools which are further applied to different problems involving multi-agent formations. The thesis considers the challenging case of agents subject to dynamical constraints. To deal with these issues, well established concepts like set-theory, differential flatness, Model Predictive Control (MPC), Mixed-Integer Programming (MIP) are adapted and enhanced. Using these theoretical notions, the thesis concentrates on understanding the geometrical properties of the multi-agent group formation and on providing a novel synthesis framework which exploits the group structure. In particular, the formation design and the collision avoidance conditions are casted as geometrical problems and optimization-based procedures are developed to solve them. Moreover, considerable advances in this direction are obtained by efficiently using MIP techniques (in order to derive an efficient description of the non-convex, non-connected feasible region which results from multi-agent collision and obstacle avoidance constraints) and stability properties (in order to analyze the uniqueness and existence of formation configurations). Lastly, some of the obtained theoretical results are applied on a challenging practical application. A novel combination of MPC and differential flatness (for reference generation) is used for the flight control of Unmanned Aerial Vehicles (UAVs).

La linguistique informatique a pour objet de construire un modèle formel des connaissances linguistiques, et d’en tirer des algorithmes permettant le traitement automatique des langues. Pour ce faire, elle s’appuie fréquemment sur des grammaires dites génératives, construisant des phrases valides par l’application successive de règles de réécriture. Une approche alternative, basée sur la théorie des modèles, vise à décrire la grammaticalité comme une conjonction de contraintes de bonne formation, en s’appuyant sur des liens profonds entre logique et automates pour produire des analyseurs efficaces. Notre travail se situe dans ce dernier cadre. En s’appuyant sur plusieurs résultats existants en informatique théorique, nous proposons un outil de modélisation linguistique expressif, conçu pour faciliter l’ingénierie grammaticale. Celui-ci considère dans un premier temps la structure abstraite des énoncés, et fournit un langage logique s’appuyant sur les propriétés lexicales des mots pour caractériser avec concision l’ensemble des phrases grammaticalement correctes. Puis, dans un second temps, le lien entre ces structures abstraites et leurs représentations concrètes (en syntaxe et en sémantique) est établi par le biais de règles de linéarisation qui exploitent la logique et le lambda-calcul. Par suite, afin de valider cette approche, nous proposons un ensemble de modélisations portant sur des phénomènes linguistiques divers, avec un intérêt particulier pour le traitement des langages présentant des phénomènes d’ordre libre (c’est-à-dire qui autorisent la permutation de certains mots ou groupes de mots dans une phrase sans affecter sa signification), ainsi que pour leur complexité algorithmique. / The goal of computational linguistics is to provide a formal account linguistical knowledge, and to produce algorithmic tools for natural languageprocessing. Often, this is done in a so-called generative framework, where grammars describe sets of valid sentences by iteratively applying some set of rewrite rules. Another approach, based on model theory, describes instead grammaticality as a set of well-formedness logical constraints, relying on deep links between logic and automata in order to produce efficient parsers. This thesis favors the latter approach. Making use of several existing results in theoretical computer science, we propose a tool for linguistical description that is both expressive and designed to facilitate grammar engineering. It first tackles the abstract structure of sentences, providing a logical language based on lexical properties of words in order to concisely describe the set of grammaticaly valid sentences. It then draws the link between these abstract structures and their representations (both in syntax and semantics), through the use of linearization rules that rely on logic and lambda-calculus. Then in order to validate this proposal, we use it to model various linguistic phenomenas, ending with a specific focus on languages that include free word order phenomenas (that is, sentences which allow the free reordering of some of their words or syntagmas while keeping their meaning), and on their algorithmic complexity.

We consider the set of all spacelike embeddings of the circle S1 into a spacetime R1 × S1 with a metric globally conformal to the Minkowski metric. We identify this set and the group of conformal isometries of this spacetime as quotients of semidirect products involving diffeomorphism groups and give a transitive action of the conformal group on the set of spacelike embeddings. We provide results showing that the group of conformal isometries is a topological group and that its action on the set of spacelike embeddings is continuous. Finally, we point out some directions for future research.

<p>ABSTRACT</p><p>The purpose with the investigation was to find if there is a relation between daily health active and too reusing theoretic learning for health promotion school’s pupil. In the investigation I have focused into if the Health promotion school’s student has better result at the nation’s test (NT) in Swedish, English and in mathematic in the fifths grade, than the ordinary school that isn’t health promotion school. The personal feelings of the two schools are that there is a connection between health active and too reusing theoretic learning. My study is a comparing fall study.</p><p>Method procedure: The investigation was done with help from two methods, the first one was a quantitative method, to now how many in fifth grade class of the two schools was failed on the NT in Swedish, English and in mathematic. The other method that I used in my investigation was quality interviews of five people from the two schools.</p><p>Conclusion; The most important result that appears in the investigation shows that the health school had worse result on NT, than de ordinary school specific for the year 2005/2006. But the Health promotion School’s boys have better result in mathematic than the ordinary school boys. In my interviews it appears that teachers feel that higher levels of physical activeness for students have a positive relation to the theoretic learning.</p> / <p>SAMMANFATTNING</p><p>Mitt Syfte är att undersöka om det finns något samband mellan daglig fysisk aktivitet och ökad teoretisk inlärning för skoleleverna på hälsofrämjande skolan. Där jag ska undersöka om hälsofrämjande skolan får bättre resultat på de nationella proven (NP) i svenska, engelska och matematik årskurs 5, än i en som inte är hälsofrämjande skola. Samt om personalen på de två skolorna upplever om det finns något samband mellan fysisk aktivitet och ökad teoretisk inlärning. Där min studie är en jämförande fallstudie.</p><p>Metodiskt tillvägagångssätt; Undersökningen genomfördes med hjälp två metoder, den första var en kvantitativ metod, för att se hur många som var underkända i NP för årskurs fem i svenska, engelska och matematik, i de utvalda klasserna på de två skolorna. Den andra metoden som jag använde i min undersökning var kvalitativa intervjuer av fem personer från de två utvalda skolorna.</p><p>Slutsats; De viktigaste resultaten som framkom i undersökning visar att den hälsofrämjande skolan hade sämre resultat i NP, än den vanliga skolan speciellt för året 2005/2006. Men att den hälsofrämjande skolans pojkar hade bättre resultat på matematik än den vanliga skolan pojkar. Det som framkom genom mina intervjuer är att lärarna upplever att ökad fysisk aktivitet har en positiv koppling för den teoretiska inlärningen.</p>

As predicted by Gordon Moore, the number of transistors on a chip has roughly doubled every two years. Microprocessors featuring over a billion transistors are no longer science fiction. For example, Intel’s Itanium 9000 series and Intel’s Xeon 7400 series of processors feature 1.7 and 1.9 billion transistors respectively. To keep up with the emerging needs of contemporary very large scale integration (VLSI) design, industrial hardware description languages (HDLs) like Verilog and VHDL must be significantly enhanced. This thesis pinpoints some of the main shortcomings of the latest Verilog standard (IEEE 1364-2005) and shows how to overcome them by extending the language in a backward compatible way. To be able to cope with more complex circuits, well-understood higher-level abstraction mechanisms are needed. Verilog is already equipped with promising generative constructs making it possible to concisely describe a family of circuits as a parameterized module; however these constructs suffer from two problems: First, their expressivity is limited and second, they are not adequately supported by current tools. For instance, there are no static guarantees about the properties of the description generated as a result of instantiating a generic description with particular parameter values. Addressing both problems while remaining backward compatible led us to select a statically typed two-level languages (STTL) formal framework. By formalizing a core subset of Verilog as an STTL, we were able to define a static type system capable of: 1) checking the realizability of a description, 2) detecting bus width mismatches and array bounds violations, and 3) providing parametric guarantees on the resources required to realize a generic description. The power of the chosen framework is once more demonstrated as it also allows us to enrich the language with a new set of constructs that are designed to be expanded away when instantiated. To experiment with these ideas we implemented VPP, a Verilog Preprocessor with a built-in type checker. VPP is an unobtrusive tool accepting extended Verilog descriptions but generating descriptions compatible with any tool compliant with the Verilog standard. Our experience throughout this research showed that STTLs present a particularly suitable framework to formalize and implement generative features of a language. / Rice University, National Science Foundation (NSF) SoD award 0439017, Intel Corporation, Semiconductor Research Corporation (SRC) Task ID 1403.001