The use of rollback is a fundamental flaw in some existing distributed control systems because the advance in time and in external world situations means that what had been a correct state in the past may no longer be a correct state in real time and distributed systems. In such systems rollback is not restoring to a state that is consistent with the current external environment. Forward error recovery provides a potential solution to such a situation to handle exception rather than backward recovery. A contingency is an unusual but anticipated situation for which the normal flow of instructions would not produce the appropriate results that should be expected. We will discuss how to handle contingencies and exceptions in a SCADA (Supervisory Control and Data Acquisition) system using resumption and termination models of exception handling.

It has been proposed that relapse vulnerability in previously dependent individuals results from augmentation of drug-induced reinforcement due to repeated associations between the interoceptive properties of the drug and reduction of acute withdrawal distress. To test this hypothesis, male Sprague-Dawley rats self-administered 0.05 mg/kg/inf heroin on continuous and progressive ratio (PR) schedules. During this period, they also received injections of vehicle or escalating doses of heroin. Following tests of naloxone-precipitated withdrawal (0.01 or 0.1 mg/kg, SC), as well as abstinence (4 days), and extinction training (9 sessions), they were pre-treated with vehicle or yohimbine (0.5 mg/kg, IV) and tested for resumption of heroin self-administration (0.05 mg/kg/inf) on continuous and PR schedules (Experiments 1 & 2), or tested for reinstatement in extinction conditions. Differences between vehicle- and heroin-injected rats were noted on self-administration on the continuous reinforcement schedule, but not on the PR schedule, in spite of greater signs of withdrawal precipitated by naloxone in the heroin-injected rats. More importantly, there were no group differences in resumption of heroin self-administration, and this was not altered by yohimbine. These results suggest that relapse vulnerability cannot be uniquely ascribed to the altered reinforcing action of drugs; contextual and other conditioning factors must play a role in modulating resumption of drug intake after periods abstinence.

Les interruptions sont une menace pour la réalisation des procédures dans un contexte opérationnel critique tel que l’aéronautique. De nombreux accidents et incidents étudiés par des organismes d’enquêtes ont révélé que l’un des nombreux facteurs impliqué concerne les interruptions. Elles entraînent des effets délétères au niveau des performances à la fois en matière de temps et d’erreurs dans la mesure où elles créent la nécessité de reprendre la tâche interrompue, induisant alors une tâche de mémoire prospective. Notre travail vise à améliorer les performances d’individus qui, comme les pilotes, effectuent de mémoire des procédures dont la suite d’actions est spatialement située dans leur environnement de travail alors même que les instructions sont présentées verbalement. Nous appuyant sur le modèle d’activation de buts (Altmann & Trafton, 2002) mais aussi sur des travaux connexes qui nous suggèrent des conditions favorisant la récupération des intentions d’actions, nous explorons la possibilité de diminuer les effets délétères des interruptions en réalisant des changements dans l’environnement des individus. Ces modifications interviendront soit lors de l’encodage de la procédure soit lors de son exécution pour aider à reprendre la tâche interrompue. Deux expériences, dans lesquelles les participants devaient réaliser une procédure mimant le comportement attendu lors d’une procédure normale de vol, ont permis d’évaluer les changements proposés. Nous avons collecté des données générales temporelles et d’erreurs en nous intéressant particulièrement à la principale mesure étudiée dans la littérature sur les interruptions (le temps de reprise de la tâche principale). Ces expériences ont été complétées par un pré-test de l’adaptation du protocole avec des pilotes de ligne.Tout d’abord, lors l’encodage de la procédure, nous montrons à travers l’expérience 1 que favoriser des formats d’instruction qui respectent les caractéristiques spatiales de la procédure va améliorer les performances des individus. Le format d’instruction visuo-spatial, qui fournit les relations spatiales entre les objets de la procédure améliore en effet les performances, comparé au format verbal et favorise notamment la reprise de la tâche interrompue. La diminution du niveau d’interférence permet au but suspendu d’être récupéré plus rapidement et efficacement. Ensuite, lors de la phase d’exécution de la tâche, les résultats de l’expérience 2 montrent qu’il est possible de soutenir plus directement la récupération du but interrompu après une interruption de tâche en fournissant un indice visuel qui améliore la reprise de la tâche. Ce résultat s’observe notamment lorsque l’indice indique la prochaine action correcte (indice prospectif) comparé à un indice sur la dernière action effectuée (indice rétrospectif). Avec ces expériences, nous proposons également de nouvelles mesures d’ajustement du temps et des erreurs, ainsi qu’un possible effet diffus de l’interruption que nous avons observé après la reprise de la tâche. Finalement, nous fournissons des recommandations pour la conception de systèmes embarqués destinés à aider le pilote lors de la réalisation des procédures de vol. / Interruptions are a major threat for procedures completion especially in critical contexts such as aeronautics. A lot of accidents analyzed by legal security organizations have underscored the role of interruption as one of the many factors involved in accident frequency. In fact, interruptions create a prospective memory task as interrupting someone implies that he must remember the main task to continue it after the interruption. As a result, interruptions could bring negative effects such as long resumption lag or errors when someone tries to remember what he was doing. Our work aims to increase individuals’ performance, such as pilots, when they are performing procedures known by heart in a spatialized work environment with mostly verbal instructions. From the goal activation memory model (Altmann & Trafton, 2002) and others works, we will explore ways to decrease the negative effect of interruptions by modifying encoding format of the task and by providing cues in order to help them recovering the suspended goal. In our two experiments, people had to realize procedures that mimic aeronautical ones. These procedures are designed to collect general data (time and error), and most particularly concerning the main effect of interruption which is the resumption lag of the primary task. These two experiments have been followed by an adaptation of the method with pilots on a flight simulator. First, for the procedure encoding (experiment 1), results showed that when we use an instruction format that match the task characteristics, individual’s performance increases. Indeed, visuo-spatial format that gives spatial relationship between tasks’ elements, increases individuals’ performance compared to the verbal format. These results are linked to the decrease of the interference level due to the balanced strengthening goals. Second, we have focused our attention on the execution phase of the task (experiment 2) and our results showed that giving a visual cue may increase the performance especially concerning the resumption lag. These results can be observed when the cue concerns the next correct action of the sequence (prospective cue) rather than the last action before the interruption (retrospective cue). Along these experiments, we also propose new adjustment measures of time and error and a possible diffuse effect of the interruption after the task resumption. Finally, we will give recommendations to conceive future system that aims to help pilots to perform their job.

This dissertation concerns one of the long-term debates about whether an innate grammar, i.e. Universal Grammar, is necessary for a child to acquire a language. The researchers who do not agree that an innate grammar needs to exist argue that the input or the child's experience of language is sufficient to acquire a language. In my work, I examine the relative clause, which is a complex structure cross-linguistically, as a case study to investigate the controversy between the role of innate grammar and the role of input in language acquisition. Based on both the comprehension data of Chinese-speaking children that I collected and the statistical analyses of corpora that I completed, I suggest that a satisfactory theory of language acquisition needs to still incorporate an innate grammar in order to accommodate the various and sometimes inconsistent input properties I document. Nevertheless, the acquisition pattern cannot be explained well without a good understanding of language-specific properties and of their potential interactions with language-external factors such as the comprehension system that may be at work in acquisition.

Phénomène brutal et encore mal connu, la reprise d'altération se traduit par une subite accélération de la vitesse d'altération du verre, due à la déstabilisation de la couche amorphe et passivante préalablement formée à sa surface. En comprendre l'origine, et en mesurer les conséquences, sont des enjeux majeurs pour la prédiction du comportement à long terme des verres nucléaires.Cette étude lie quantitativement le degré d'altération d'un verre de référence à six oxydes et les mécanismes de formation des zéolithes et C-S-H qui contrôlent la chimie de la solution. Le rôle d'indicateur de reprise joué par la décroissance de la concentration en aluminium est mis en évidence. Il apparaît qu'occurrence et vitesse de reprise sont corrélées au couple (T, pH) ; même dans les situations les plus défavorables, la vitesse de reprise reste inférieure d'un ordre de grandeur environ à la vitesse initiale d'altération, qui reste le régime cinétique le plus rapide. Jusqu'alors limitée aux pH alcalins, une nouvelle approche est mise en œuvre pour étendre la caractérisation des reprises d'altération dans des conditions plus représentatives de celles d'un stockage géologique. Elle a nécessité le développement d'un outil : l'ensemencement qui réduit, voire supprime, la période de latence précédant la reprise. Les résultats obtenus en font un puissant outil pour la compréhension du rôle joué par les zéolithes sur la déstabilisation de la pellicule amorphe et pour la modélisation des reprises d'altération. Une démarche de modélisation géochimique du phénomène de reprise est proposée en s'appuyant sur le formalisme du modèle GRAAL. Elle repose sur le calcul des constantes thermodynamiques des zéolithes, sur l'implémentation de leurs lois cinétiques de nucléation et de croissance et sur des hypothèses relatives à la solubilité de la couche amorphe. Lorsque la précipitation des zéolithes consomme des alcalins, l'altération du verre — dont elle est le moteur — en libère. Le modèle éclaire l'importance de tels couplages chimiques et montre que, dans la stœchiométrie des verres nucléaires, leurs effets cumulés sont à l'origine d'une diminution du pH limitant à son tour la précipitation des zéolithes. / A sudden and still poorly understood phenomenon, the resumption of alteration results in a sudden acceleration of the glass alteration rate due to the destabilization of the amorphous passivating layer formed on the glass surface. Understanding the origin and the consequences of this phenomenon is a major issue for the prediction of nuclear glass long-term behavior.This study quantitatively links the alteration degree of a six-oxide reference glass and the formation mechanisms of zeolites and C-S-H that control the solution chemistry. The role played by the decrease in aluminum concentration as an indicator of resumption is highlighted. It appears that the resumption occurrence and rate are correlated to the couple (T, pH), but even in the most adverse situations the resumption rate is lower than the initial alteration rate, which remains the fastest kinetic regime. Previously limited to alkaline pH, the characterization of alteration resumptions was extended to conditions more representative of those found in a geological repository. This approach required the development of a new tool: seeding, that reduces or eliminates the latency period preceding a resumption. The results obtained demonstrate its usefulness in understanding the role of zeolites in amorphous layer destabilization and for modeling alteration resumptions.A geochemical modeling approach to alteration resumption is proposed, based on the formalism of the GRAAL glass alteration model. It is based on the calculation of zeolite thermodynamic constants, on the implementation of their nucleation and growth kinetics, and on assumptions related to the solubility of the amorphous layer. When zeolite precipitation consumes alkali, glass alteration—driven by zeolite precipitation—releases alkali. The model highlights the importance of such chemical couplings and shows that, in the stoichiometry of French nuclear reference glass, their cumulative effects are the cause of a pH decrease which limits zeolite precipitation.

Resumption has been the object of lively research (Doron 1982; Sells 1984; McClauskey 1990; 2002; Shlonsky 1992; Cann 1999; Sharvit 1999; Alexopoulou 2006; Guilliot 2006; Malkawi 2009; Rouveret 2011) and various analyses consider it a form of agreement, a last syntactic resort or a special kind of ellipsis. On the theoretical side, I survey the issues that are the background of the research, such as the nature of the pronouns that are involved in resumption. I develop a syntactic analysis of resumptive pronouns in which they are clitics (Cardinaletti and Starke 1999; Dechaine and Wiltschko 2002; Roberts 2010) and they form a complex determiner phrase together with the relative pronoun or interrogative pronoun. I argue that when resumption is obligatory, it follows from requirements in the syntax and only when it is optional it is a phenomenon at the syntax-pragmatics interface. On the empirical side, I contrast and compare the pronominal paradigms of Arabic and Romanian, an Eastern Romance language which strikingly shows a similar pattern of resumption as Arabic: (i) obligatory resumption in relativization, (ii) designated relative pronoun. Though for Romanian nobody has disputed the nature of the clitic pronouns as clitic in the sense that I am adopting (Cardinaletti and Starke 1999), it has not been thoroughly documented either. I then discuss the pragmatics of resumption in contexts in which it is optional, such as D-linked questions in Arabic. The difference between obligatory resumption and optional resumption is not found in the syntax, because this same syntactic derivation is associated with different interpretive effects depending on whether it occurs in obligatory or in optional contexts. I argue that the presence of the pronoun when it is not required by the syntax triggers a change in interpretation: the module pragmatics assigns it a pragmatic feature.

abstract: A Virtual Private Network (VPN) is the traditional approach for an end-to-end secure connection between two endpoints. Most existing VPN solutions are intended for wired networks with reliable connections. In a mobile environment, network connections are less reliable and devices experience intermittent network disconnections due to either switching from one network to another or experiencing a gap in coverage during roaming. These disruptive events affects traditional VPN performance, resulting in possible termination of applications, data loss, and reduced productivity. Mobile VPNs bridge the gap between what users and applications expect from a wired network and the realities of mobile computing. In this dissertation, MobiVPN, which was built by modifying the widely-used OpenVPN so that the requirements of a mobile VPN were met, was designed and developed. The aim in MobiVPN was for it to be a reliable and efficient VPN for mobile environments. In order to achieve these objectives, MobiVPN introduces the following features: 1) Fast and lightweight VPN session resumption, where MobiVPN is able decrease the time it takes to resume a VPN tunnel after a mobility event by an average of 97.19\% compared to that of OpenVPN. 2) Persistence of TCP sessions of the tunneled applications allowing them to survive VPN tunnel disruptions due to a gap in network coverage no matter how long the coverage gap is. MobiVPN also has mechanisms to suspend and resume TCP flows during and after a network disconnection with a packet buffering option to maintain the TCP sending rate. MobiVPN was able to provide fast resumption of TCP flows after reconnection with improved TCP performance when multiple disconnections occur with an average of 30.08\% increase in throughput in the experiments where buffering was used, and an average of 20.93\% of increased throughput for flows that were not buffered. 3) A fine-grained, flow-based adaptive compression which allows MobiVPN to treat each tunneled flow independently so that compression can be turned on for compressible flows, and turned off for incompressible ones. The experiments showed that the flow-based adaptive compression outperformed OpenVPN's compression options in terms of effective throughput, data reduction, and lesser compression operations. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2017

People spend a significant amount of time using computers at work, at home, or school. Given users switch tasks and are frequently interrupted or distracted while working, reconstructing working context is inevitable. For example, users sometimes need to revisit an arbitrary task from the past to retrieve necessary information (e.g., webpages, files). In this scenario, retrieving working context can be time-consuming or even impossible; users may rely on their memory and may not be able to retrieve the relevant documents that they used before. Sometimes application provides a chronological history of recently opened documents (files, websites). However, it can be challenging to find the right information they need as there are many and users may not recognize from the text-based data (e.g. web page titles, document file name). Therefore, helping them reconstruct mental context and retrieving relevant applications and files can enhance overall productivity. To that end, the concept of self-tracking, which is widely used in health and fitness, is applied to the context of computer usage. In particular, the idea of using a history of a computer screen can provide visuals that users can associate with existing meta-data (file location, web page URL, time). A user can reconstruct working context from the screen visual that they recognize. The idea of using a visual history of a computer screen activities is tested through the development of ScreenTrack, a program that captures a computer screen regularly and let a user watch a time-lapse video made of computer screenshots, and retrieve applications, files, and web pages from a snapshot of a screen. I hypothesize that the chronological history of computer screen activities can effectively help users navigate visual working context and retrieve information that is associated with a snapshot. Through a controlled user study, it was found that participants were able to retrieve information that they were asked more quickly with ScreenTrack than the control condition with statistical significance (p<0.005). Besides, participants gave positive feedback on the software that they would like to use such software in their computers in various context, but expressed potential concerns of using such software for privacy and computer storage problems. In this thesis, I motivate the need of such software, review the related work, share the design consideration, and introduce design and implementation process, validate the effects of ScreenTrack with a controlled user study. / Master of Science / Nowadays, people spend a significant amount of time using computers at work, at home, or school. Users switch software frequently and are often interrupted or distracted while working. Hence recalling previous working context is inevitable for computer users. Recalling previous working context can take lots of time or even impossible. Because users may rely on their own memory and may not be able to recall and retrieve the relevant documents that they used before. Sometimes software provides a history of recently opened documents (files, websites). However, it can be challenging to find the right information they need as there are many recorded information. And users may not recognize documents of interest from the textual data (e.g. web page titles, document file name). Therefore, helping people restore previous working context and reopening relevant software and files can enhance overall productivity. I designed and developed a software, called ScreenTrack. This software can take pictures of current computer screen regularly and store them. Later, users can watch a video made of stored screenshots. Based on this video, individuals can recall their previous computer activities and reopen closed software, websites, files, and documents from a snapshot. Through a controlled user study, I found that participants were able to retrieve previous computer activities more quickly under the help of ScreenTrack than without ScreenTrack. With ScreenTrack, participants spend 27.1 seconds on average to reopen a previous closed website, 37% faster than without it. Furthermore, participants gave positive feedback on this software that they would like to use ScreenTrack in the future for various purposes, for doing researches and reading papers.

Cette thèse fournit une étude comparative des constructions disloquées à gauche en anglais et en arabe standard (AS). À la lumière des cadres théoriques récents, nous examinons la syntaxe et les propriétés discursives de la dislocation à gauche en AS que nous comparons avec leurs équivalents en anglais. La première partie de cette thèse est consacrée à l'étude des propriétés syntaxiques translinguistiques des constructions placées dans la périphérie gauche. Il est soutenu notamment que l’anglais et l’AS partagent beaucoup de similarités syntaxiques. Une typologie prenant en compte des faits constatés dans les structures disloquées à gauche AS est proposée. La seconde partie est consacrée à la résomptivité dans les constructions disloquées à gauche. Il est démontré que le résomptif dans la HTLD est un pronom indépendant étant donné qu’il n y a aucune exigence syntaxique pour l’élément disloqué d'être présent. De même, il est soutenu que l’optionalité du résomptif dans la CLD est mieux expliquée en termes discursifs. Dans la troisième partie, nous proposons que les constructions CLD en AS suivent le même modèle que les CLD en anglais, en ce qu'elles expriment une fonction de Focus contrastif préétabli dans le discours. De même, nous soutenons que les HTLD en AS sont analogues aux données translinguistiques en ce sens que ce sont des entités discursives de saillance préalable, étant déjà présentes dans la conscience du locuteur. En outre, nous démontrons que l’insertion du PR dans la CLD II n’est ni facultative, ni n’émane d’effets de spécificité / référentialité ; il s'agit plutôt d'un dispositif discursif qui promeut l’élément disloqué au statut de Topique. / In this thesis, I offer a comparative approach to Left-dislocation constructions in both standard Arabic (SA) and English. Under recent theoretical developments, I investigate the syntax and the discourse properties of constructions involving left-dislocation in SA and compare them with their English counterparts. In the first part, I discuss the syntactic properties of SA left-dislocation and compare them with cross-lingusitic CLLD, HTLD, and Topicalization. A further comparison between SA and English Left-dislocation is presented provides an important ground for an evaluation of the SA data. A new classification of Left-dislocated structures, which takes into account SA and English data, is offered. In the second part, I investigate the status of resumptives in both HTLD and CLD. I claim that in HTLD, the RP is a syntactically non-connected argument but a pragmatically “connected” referential pronoun, provided the HTLDed is salient enough in discourse. It is further argued that resumptives and gaps in CLD are not in free variation. In the third part, it is proven that SA CLD left-dislocation constructions pattern alike with English data at the discourse level. Likewise, it is argued that the absence of resumptives in CLD I does not promote the CLDed element to a Topic status. It is only the overt coreference of a RP with a discourse-linked antecedent in CLD II that renders the CLDed salient in discourse thereby promoting it to a Topic status.

Variation in dative resumption among and within Alemannic varieties of German strongly favors an Evaluator component that makes use of optimality-theoretic evaluation rather than filters as in the Minimalist Program (MP). At the same time, the variation is restricted to realizational requirements. This supports a model of syntax like the Derivations and Evaluations framework (Broekhuis 2008) that combines a restrictive MP-style Generator with an Evaluator that includes ranked violable (interface) constraints.