Technique de coordination de prétentions en concours permettant de désigner une prétention, dite prioritaire, devant être mise en œuvre avant les autres sans les exclure du concours, la priorité suscite des interrogations quant à son caractère juridique. L’identification du mécanisme de priorité suppose d’abord d’en établir la spécificité quant aux autres mécanismes de traitement de la pluralité et quant aux éléments qui peuvent être coordonnés. Elle suppose ensuite d’en établir l’utilité. Il apparaît d’une part une diversité des fondements du mécanisme de priorité, qu’il s’agisse des fondements de l’exclusion du traitement égalitaire ou de ceux de la faveur accordée à une prétention déterminée et d’autre part une unité des effets du mécanisme de priorité, que ce soit sur la situation de concours ou sur les personnes concernées par le concours. Mais l’identification du mécanisme de priorité ne suffit pas à l’élaboration d’une théorie générale : encore faut-il examiner l’encadrement de la règle de priorité. Cet encadrement s’observe en premier lieu quant à la création de la règle de priorité. L’élaboration de cette dernière est encadrée en raison de l’objet de la règle de priorité, afin de protéger les tiers concurrents et les parties à la priorité, mais également en raison des critères de la règle de priorité, qui ne doivent pas être discriminatoires. Cet encadrement s’observe en second lieu quant à l’application de la règle de priorité, par les limites à sa réalisation, dont l’efficacité et l’effectivité peuvent être questionnées mais également par les sanctions de sa violation, leur cohérence pouvant être remise en cause / Technique of coordination of competing claims, designating a priority claim which must be implemented before the implementation of other claims without excluding them from the competition, juridical character of priority does raise some questions. Firstly, to identify it, specificity of priority must be determined, in comparison to other techniques of treatment of plurality and by identifying elements which can be coordinated by priority. Secondly, identifying priority supposes establishing its utility. Priority mechanism has a diversity of bases, whether in terms of exclusion of equal treatment and in terms of favour granted to a determined claim and it has always the same effects, both on the competition situation and on the persons concerned. However, this identification is not sufficient to establish a general theory of priority in private law: framework of priority rule must be considered. On one side, creation of a rule of priority is subject to a legal framework, considering the object of the rule to protect third-parties and parties to the rule and considering criteria of the rule, in order to prohibit discriminatory criteria except for affirmative action. On other side, implementation of priority is also subject to a legal framework, whether in case of voluntary implementation, raising questions about effectiveness and effectivity of priority and in case of breach of a right of priority, consistency of remedies can call into question, mainly because of the contain of specific performance

I show how Aristotle’s theory of the priority of actuality and his theory of non-correlative actuality help prepare the way for his own positive account of the separate, non-sensible substances. Aristotle argues that actuality is prior to potentiality in Metaphysics [Theta]8, and in particular that actuality is prior in substance and in a more authoritative kind of way. I show how both of these arguments are to be understood, and how the more authoritative kind of priority (which is not substantial priority, as usually thought) is again appealed to in Metaphysics [Lamda]6 in order to draw important inferences about the primary principles. I also show how the theory of non-correlative actuality used in [Theta]8 is, just like the more authoritative kind of priority, again applied in [Lamda]6 in parallel kinds of ways. It turns out that the traditional interpretation which ascribes the notion of “pure actuality” to Aristotle is mistaken, and this comes to light once Aristotle’s theory of non-correlative actuality is properly understood and the texts are properly interpreted. / text

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In modern embedded systems, real-time applications are often executed on multi-core systems that also run non real-time critical applications. It is well known that cache sharing among multi-core systems or concurrent threads running on a single CPU potentially causes real-time application execution delays. This makes the worst-case execution time (WCET) prediction of these real-time applications more difficult. An encouraging approach to address this problem is prioritized cache. Currently, the implementation of prioritized cache is done at the architectural level using cache controllers. This thesis focuses on the implementation of two prioritized LRU (least-recently-used) cache replacement policy circuits inside the cache circuit to support the prioritized cache operation. This will decrease cache latency. The circuits are implemented using the Synopsys 28nm EDK. Based on the circuit implementation, the area and power overheads associated with prioritized cache are investigated. Two prioritized LRU circuit designs are presented.

Recently, technological developments have affected most lifestyles, especially with the growth in Internet usage. Internet applications highlight the E-commerce capabilities and applications which are now available everywhere; they receive a great number of users on a 24-7 basis because online services are easy to use, faster and cheaper to acquire. Thus E-commerce web sites have become crucial for companies to increase their revenues. This importance has identified certain effective requirements needed from the performance of these applications. In particular, if the web server is overloaded, poor performance can result, due to either a huge rate of requests being generated which are beyond the server's capacity, or due to saturation of the communication links capacity which connects the web server to the network. Recent researches consider the overload issue and explore different mechanisms for managing the performance of E-commerce applications under overload condition. This thesis proposes a formal approach in order to investigate the effects of the extreme load and the number of dropped requests on the performance of E- III commerce web servers. The proposed approach is based on the class-based priority scheme that classifies E-commerce requests into different classes. Because no single technique can solve all aspects of overload problems, this research combines several techniques including: admission control mechanism, session-based admission control, service differentiation, request scheduling and queuing model-based approach. Request classification is based on the premise that some requests (e.g. buy) are generally considered more important than others (e.g. browse or search). Moreover, this research considers the extended models from Priority Scheduling Mechanism (PSM). These models add a new parameter, such as a review model or modify the basic PSM to low priority fair model, after the discovery of ineffectiveness with low priority customers or to add new features such as portal models. The proposed model is formally specified using the π-calculus in early stage of models design and a multi-actor simulation was developed to reflect the target models as accurately as possible and is implemented as a Java-based prototype system. A formal specification that captures the essential PSM features while keeping the performance model sufficiently simple is presented. Furthermore, the simplicity of the UML bridges the gap between π-calculus and Java programming language. IV There are many metrics for measuring the performance of E-commerce web servers. This research focuses on the performance of E-commerce web servers that refer to the throughput, utilisation, average response time, dropped requests and arrival rate. A number of experiments are conducted in order to test the performance management of the proposed approaches.

In this thesis, we present a detailed analysis of hybrid point-to-multipoint free space optical (FSO)/radio frequency (RF) wireless system. Hybrid FSO/RF sys- tems have emerged as a promising solution for high data rate wireless transmission. FSO technology can be used effectively in multiuser scenarios to support Point-to- Multi-Point (P2MP) networks. In this P2MP network, FSO links are used for data transmission from a central location to multiple users. When more than one FSO link fail, the central node uses a common backup RF link to transmit a frame to a remote node using an equal priority protocol. An equal priority protocol means that the remote nodes have the same priorities in being assigned the RF link. We assume two traffic classes, a high-priority and low-priority classes. The base station reserves two transmit buffers of each user for the downlink transmission. Considering the downlink traffic from the base station to a tagged remote node, we study several performance metrics. We develop a cross-layer Markov chain model to study the throughput from central node to a remote node as well as the performance of the resulting system. / Graduate

Recently, technological developments have affected most lifestyles, especially with the growth in Internet usage. Internet applications highlight the E-commerce capabilities and applications which are now available everywhere; they receive a great number of users on a 24-7 basis because online services are easy to use, faster and cheaper to acquire. Thus E-commerce web sites have become crucial for companies to increase their revenues. This importance has identified certain effective requirements needed from the performance of these applications. In particular, if the web server is overloaded, poor performance can result, due to either a huge rate of requests being generated which are beyond the server¿s capacity, or due to saturation of the communication links capacity which connects the web server to the network. Recent researches consider the overload issue and explore different mechanisms for managing the performance of E-commerce applications under overload condition. This thesis proposes a formal approach in order to investigate the effects of the extreme load and the number of dropped requests on the performance of E- III commerce web servers. The proposed approach is based on the class-based priority scheme that classifies E-commerce requests into different classes. Because no single technique can solve all aspects of overload problems, this research combines several techniques including: admission control mechanism, session-based admission control, service differentiation, request scheduling and queuing model-based approach. Request classification is based on the premise that some requests (e.g. buy) are generally considered more important than others (e.g. browse or search). Moreover, this research considers the extended models from Priority Scheduling Mechanism (PSM). These models add a new parameter, such as a review model or modify the basic PSM to low priority fair model, after the discovery of ineffectiveness with low priority customers or to add new features such as portal models. The proposed model is formally specified using the ¿ -calculus in early stage of models design and a multi-actor simulation was developed to reflect the target models as accurately as possible and is implemented as a Java-based prototype system. A formal specification that captures the essential PSM features while keeping the performance model sufficiently simple is presented. Furthermore, the simplicity of the UML bridges the gap between ¿-calculus and Java programming language. IV There are many metrics for measuring the performance of E-commerce web servers. This research focuses on the performance of E-commerce web servers that refer to the throughput, utilisation, average response time, dropped requests and arrival rate. A number of experiments are conducted in order to test the performance management of the proposed approaches.

Ring Barrier signal controller in VISSIM traffic simulation software provides different options for configuring Transit Signal Priority. This controller emulator allows for considering arterial progression by Priority Progression parameter; preferring specific transit signal priority calls to other calls by Priority Level feature; providing more green split to the signal priority phase by Green Extension attribute. This study aims to evaluate the impact of these three parameters on the performance of transit signal priority. The study area is based on three signalized intersections of Prices Fork Road in Blacksburg, Virginia. A total of five transit lines are assumed to request signal priority. Green Extension and Priority Level were found to have significant influence on bus delays, whereas bus frequency is not a significant variable to affect TSP effectiveness (for reducing the transit delays). This study also aims to identify the traffic conditions in which the adaptive feature of VISSIM Ring Barrier Controller can be most useful. Detector Slack, Detector Adjust Threshold, and Adjust Step are the parameters that should be hardcoded in the controller for activating the adaptiveness feature. The study area (Prices Fork Road in town of Blacksburg, VA) incorporates five bus lines are assumed eligible to request priority. This study revealed that transit service overlap can enhance or exacerbate each bus performance when transit signal priority is implemented, depending on the scheduled headways and the frequency of signal priority requests in each intersection. / Master of Science