Currently, water utilities are facing monetary crises to maintain and expand services to meet the current as well as the future demands. Standard practice in pipeline infrastructure asset management is to collect data and predict the condition of pipelines using models and tools. Water utilities want to be proactive in fixing or replacing the pipes as fixing-when-it-fails ideology leads to increased cost and can affect environmental quality and societal health. There is a number of modeling techniques available for assessing the condition of the pipelines, but there is a massive shortage of methods to check the reliability of the results obtained using different modeling techniques. It is mainly because of the limited data one utility collects and absence of piloting of these models at various water utilities. In general, water utilities feel confident about their in-house condition prediction and failure models but are willing to utilize a reliable methodology which can overcome the issues related to the validation of the results. This paper presents the methodology that can enhance the reliability of model results for water pipeline performance analysis which can be used to parallel the output of the real system with confidence. The proposed methodology was checked using the dataset of two large water utilities and was found that it can potentially help water utilities gain confidence in their analyses results by statistically signifying the results. / Master of Science / Water utilities are facing monetary crises to maintain and expand services to meet the current as well as the future demands. Standard practice in pipeline infrastructure asset management is to collect data and predict the condition of pipelines using models and tools. There is a number of modeling techniques available for assessing the condition of the pipelines, but there is a massive shortage of methods to check the reliability of the results obtained using different modeling techniques. This study presents the methodology that can enhance the reliability of model results for water pipeline performance analysis which can potentially help water utilities to be proactive in fixing or replacing the pipelines with confidence. Different types of analyses on the data received from the two large water utilities (name confidential) were performed to understand and check the application of the proposed methodology in the real world and was found that it can potentially help water utilities gain confidence in their analyses results by statistically signifying the result

The purpose of this study is to understand how African-American males enrolled in middle school in Los Angeles County experienced and understood the application of the California educational code regarding discipline. Disproportionate numbers of African-American students are being suspended and expelled from public schools. This overreliance on exclusionary punishment has led to the School-to-Prison Pipeline, and the statistics related to suspension rates from school mirror that of the criminal justice system. This study captures the voices of students who are consistently referred to the office by classroom teachers in order to understand how they perceive and articulate their experiences with the school disciplinary process and how those experiences impact their academic and personal lives. Findings indicate that participants want to do well in school. The participants described many of the behaviors that triggered an office referral as trivial, such as being tardy to class, talking, or not doing their work. When their infractions were more serious, students stated that they acted out because the teacher had disrespected or antagonized them. More than anything, participants want teachers to listen to them and to respect them, and they want to be active participants in their learning.

Cette étude porte sur la caractérisation des matériaux constituant le revêtement isolant de pipeline offshore ainsi que la soudure réalisée entre les deux polymères semi-cristallins du revêtement au niveau de la jonction entre deux tubes successifs.L’épaisseur très importante du revêtement induit, au cours du procédé de soudage, des vitesses hétérogènes de chauffe et de refroidissement des matériaux. Ces dernières ont été caractérisées grâce à une instrumentation du procédé en site industriel. Une modélisation numérique intégrant les phases successives du procédé est en bon accord avec les résultats expérimentaux. Cette modélisation permet de dresser une cartographie complète des champs de température dans l’ensemble du pipeline et plus précisément dans la zone de soudage.Cette étude nous a amené à réaliser une caractérisation des deux matériaux soudés au cours de leurs fusions et cristallisations qui représentent deux étapes cruciales lors du soudage. Une attention particulière a été portée au comportement rhéologique dans la zone de transition entre l’état fondu et l’état solide et inversement. Les données en refroidissement à différentes vitesses ont été corrélées avec le taux de transformation des matériaux.Les propriétés mécaniques des isolants ont été testées ainsi que celles des soudures en prélevant des éprouvettes sur les essais effectués en site industriel. Le peu de flexibilité du procédé industriel rend difficile une investigation de l’influence des paramètres de soudage. Une expérience « image », représentative des grandeurs industrielles, a donc été développée à l’échelle du laboratoire permettant de faire varier les paramètres de soudage. Il a été montré que le point de faiblesse de l’assemblage ne se situe pas au niveau de la soudure mais dans l’un des matériaux du revêtement. / This PhD focuses on the characterization of the materials of the insulating coating of offshore pipelines as well as the welding made between the two semi-crystalline polymers of the coating at the junction of two consecutives pipes.The important thickness of the coating induces heterogeneous heating and cooling rates during the welding process. Those rates have been characterized through the implementation of thermal sensors during the industrial process. A simulation model of the different steps of the welding process is consistent with the experimental results. This simulation gives access to the thermal fields in the entire pipe and especially in the welding zone.This study allows us to characterize the two welded materials during their melting and crystallization which represent the two crucial steps during the welding. A particular attention has been drawn to their rheological behavior in the transition zone from the molten to the solid state and vice versa. The cooling data at different rates have been correlated with the transformation fraction of the materials.The mechanical properties of the insulating materials have been tested especially in the welding zone via the industrial process. However, the imposing infrastructure of the industrial process does not allow the study of the influence of welding parameters. To do so, a “mirror” experiment, representative of the industrial one, has been developed at a laboratory scale. Both the welding made via the industrial process and the “mirror” experiment have shown that the weak point of the structure is not the welding itself but one of the materials of the coating.

Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.

Master of Engineering (Research) / Soil surrounding a submarine buried pipeline consolidates as ocean waves propagate over the seabed surface. Conventional models for the analysis of soil behaviour near the pipeline assume a two-dimensional interaction problem between waves, the seabed soil, and the structure. In other words, it is often considered that water waves travel normal to the orientation of pipeline. However, the real ocean environment is three-dimensional and waves approach the structure from various directions. It is therefore the key objective of the present research to study the seabed behaviour in the vicinity of marine pipelines from a three-dimensional point of view. A three-dimensional numerical model is developed based on the Finite Element Method to analyse the so-called momentary behaviour of soil under the wave loading. In this model, the pipeline is assumed to be rigid and anchored within a rigid impervious trench. A non-slip condition is considered to exist between the pipe and the surrounding soil. Quasi-static soil consolidation equations are then solved with the aid of the proposed FE model. In this analysis, the seabed behaviour is assumed to be linear elastic with the soil strains remaining small. The influence of wave obliquity on seabed responses, i.e. the pore pressure and soil stresses, are then studied. It is revealed that three-dimensional characteristics systematically affect the distribution of soil response around the circumference of the underwater pipeline. Numerical results suggest that the effect of wave obliquity on soil responses can be explained through the following two mechanisms: (i) geometry-based three-dimensional influences, and (ii) the formation of inversion nodes. Further, a parametric study is carried out to investigate the influence of soil, wave and pipeline properties on wave-associated pore pressure as well as principal effective and shear stresses within the porous bed, with the aid of proposed three-dimensional model. There is strong evidence in the literature that the failure of marine pipelines often stems from the instability of seabed soil close to this structure, rather than from construction deficiencies. The wave-induced seabed instability is either associated with the soil shear failure or the seabed liquefaction. Therefore, the developed three-dimensional FE model is used in this thesis to further investigate the instability of seabed soil in the presence of a pipeline. The widely-accepted criterion, which links the soil liquefaction to the wave-induced excess pressure is used herein to justify the seabed liquefaction. It should be pointed out that although the present analysis is only concerned with the momentary liquefaction of seabed soil, this study forms the basis for the three-dimensional analysis of liquefaction due to the residual mechanisms. The latter can be an important subject for future investigations. At the same time, a new concept is developed in this thesis to apply the dynamic component of soil stress angle to address the phenomenon of wave-associated soil shear failure. At this point, the influence of three-dimensionality on the potentials for seabed liquefaction and shear failure around the pipeline is investigated. Numerical simulations reveal that the wave obliquity may not notably affect the risk of liquefaction near the underwater pipeline. But, it significantly influences the potential for soil shear failure. Finally, the thesis proceeds to a parametric study on effects of wave, soil and pipeline characteristics on excess pore pressure and stress angle in the vicinity of the structure.

With over 830,000 km of operating pipeline in Canada alone, their safe and continued functioning underpins much of daily life. A key type of risk associated with pipelines is third-party damage, damage caused by actions not associated with the pipelines normal operation. The question of whether the pressurized structure like pipeline or pressure vessel would undergo “unzipping” due to the third-party impact is crucial for the safety of pipelines or pressure vessels in service needs to be answered. Thus, we endeavour to develop a methodology for assessment of design solutions effectiveness to prevent a pipeline or pressure vessel failure in an abrupt explosion-like fashion due to third-party damage. Model of crack propagation determining whether the “unzipping” rupture will occur is viewed as a key element in the safety-driven design procedure providing significant effect on the safety of operation. The crack propagation modeling is achieved through the use of nonlinear fracture mechanics technique. The method of singular integral equations is used to calculate the critical stress required for the catastrophic failure of pipeline or pressure vessel damaged due to third-party interference. The model was implemented as a FORTRAN program. Testing of the developed numerical tool was performed using experimental data available in the literature, with the results showing promising agreement. / February 2016

L'objectif de ce travail était d’élaborer la brique de base d'un convertisseur analogique numérique supraconducteur à architecture pipeline, fonctionnant à 30GHz de fréquence d’échantillonnage. Ce convertisseur est constitué d’un bloc de N comparateurs disposés en cascade le long d’une ligne de transmission. Chaque étage de comparaison est constitué d'un SQUID rf mutuellement couplé à un tronçon de ligne de transmission. Lorsque le signal à convertir arrive à la hauteur d'un comparateur, il génère un champ magnétique qui induit un courant dans le SQUID rf. Ce courant pourra faire commuter la jonction Josephson du SQUID rf dans certains cas, en fonction des caractéristiques internes de la jonction Josephson du SQUID et de son environnement. La commutation, qui s’accompagne de l’apparition d’une impulsion de tension quantifiée SFQ, a été étudiée de manière théorique et expérimentale en fonction des différents paramètres du problème. / Superconductive analogue to digital converters (ADC) generally have speed and power dissipation advantages which should enable their application in telecommunication, medicine, and where an analogue signal (delivered e.g. by a sensor) needs to be digitized for post-processing.We are developing a new concept of analogue to digital converter using high critical temperature (Tc=90K) superconductors and operating at 30GHz; this converter is based an original structure, the pipeline architecture. The principle is to place a cascade of N comparators along a transmission line on which propagates the up-converted analogue signal. The carrier frequency is used in this case as a sampling signal.Each comparator, made with a SQUID loop, produces one bit at the carrier frequency: it codes the input signal by generating or not an RSFQ pulse (respectively "1” or “0"), and passes the residue (attenuated signal) in the following comparator.Here, we present steps for the comparator optimisation and mask design.Besides simulation results, we present the measurements at 30GHz carrier frequency of the comparator designed at low critical temperature (LTS). Finally, we suggest other tools to develop the optimised low critical temperature converter and we proposed the concept of the comparator operating at high critical temperature (HTS).

Under the current intensive development of the world economy, there is a significant increase in integration of strategic sectors in countries towards the regional and international networks. Therefore, the potential of pipeline transport begins to take special foreign economic and geopolitical importance. The current status and development of this field is the object of an increased interest of all parties that are involved in the transport of raw materials. The more trades there are with oil and gas, the more issues related to its transport are occurred which all parties involved in the transport system faced to deal with. In the context of rapidly developing interconnection of global economies on regional level along with its undeniable reflection on international situation, it makes the functioning of already existing system of pipelines and realization of new projects related to construction of pipelines, with issues of economic, ecological and technical character that play an important role in delivering strategic energy products to world markets. At the same time the strong competition for the construction of pipeline facilities increases its geopolitical significance.

Même si les réseaux de données ont beaucoup évolué au cours des dernières décennies, les paquets sont presque toujours transmis d’un nœud à l’autre comme des blocs de données inaltérables. Cependant, ce paradigme fondamental est aujourd’hui remis en question par des techniques novatrices comme le codage réseau, qui promet des améliorations de performance et de fiabilité si les nœuds sont autorisés à mixer des paquets entre eux. Les réseaux sans fil manquent de fiabilité en raison des obstacles ou interférences que subissent les liens sans fil, et ces problèmes peuvent empirer dans des topologies maillées avec de multiples relais potentiels. Dans ce travail, nous nous concentrons sur l’application du codage réseau intra-flux aux flux unicast dans les réseaux sans fil, avec pour objectif d’améliorer la fiabilité des transferts de données et de discuter des opportunités de déploiement et des performances. Tout d’abord, nous proposons une borne inférieure pour la redondance, puis un algorithme opportuniste distribué, pour adapter le codage aux conditions du réseau et permettre la livraison fiable des données dans un réseau sans fil maillé, tout en prenant en compte les besoins de l’application. En outre, puisque les opérations requises pour le codage réseau sont coûteuses en termes de calcul et de mémoire, nous étendons cet algorithme pour s’adapter aux contraintes physiques de chaque nœud. Ensuite, nous étudions les interactions du codage intra-flux avec TCP et son extension MPTCP. Le codage réseau peut en effet améliorer les performances de TCP, qui ont tendance à être plus faibles sur les liens sans fil, moins fiables. Nous observons l’impact des problèmes d’équité qui se posent quand des flux codés fonctionnent en parallèle avec des flux traditionnels non codés. Pour finir, nous explorons deux manières différentes d’améliorer les performances de MPTCP dans les environnements sans fil : le faire fonctionner sur du codage réseau, et implémenter directement le codage directement dans le protocole MPTCP tout en préservant sa compatibilité avec TCP / Even if packet networks have significantly evolved in the last decades, packets are still transmitted from one hop to the next as unalterable pieces of data. Yet this fundamental paradigm has recently been challenged by new techniques like network coding, which promises network performance and reliability enhancements provided nodes can mix packets together. Wireless networks rely on various network technologies such as WiFi and LTE. They can however be unreliable due to obstacles, interferences, and these issues are worsened in wireless mesh network topologies with potential network relays. In this work, we focus on the application of intra-flow network coding to unicast flows in wireless networks. The main objective is to enhance reliability of data transfers over wireless links, and discuss deployment opportunities and performance. First, we propose a redundancy lower bound and a distributed opportunistic algorithm, to adapt coding to network conditions and allow reliable data delivery in a wireless mesh. We believe that application requirements have also to be taken into account. Since network coding operations introduce a non negligible cost in terms of processing and memory resources, we extend the algorithm to consider the physical constraints of each node. Then, we study the interactions of intra-flow coding with TCP and its extension MPTCP. Network coding can indeed enhance the performances of TCP, which tends to perform poorly over lossy wireless links. We investigate the pratical impact of fairness issues created when running coded TCP flows besides legacy non-coded TCP flows. Finally, we explore two different ways to enhance the performance of MPCTP in wireless environments : running it over network coding, and implementing the coding process directly in MPTCP while keeping it fully TCP-compatible.

As cloud-native applications become more distributed, complex, and unpredictable with the adoption of microservices and other new architectural components, traditional monitoring solutions are inadequate in providing end-to-end visibility and proactively identifying deviations from expected behaviour before they become disruptive to services. In response to these challenges, observability-driven development (ODD) is proposed as a new methodology that leverages tools and practices to observe the state and detect the behaviour of systems. Unlike the leading IT giants developing their proprietary tools and platforms, some non-IT companies and smaller organizations still have difficulty adopting observability-driven development. Proprietary development demands extensive resources and manpower, while connecting to third-party platforms may compromise data security. This thesis proposed an end-to-end observability pipeline that is composed of merely open-source components. The pipeline collects and correlates metrics, logs, and traces to facilitate software development and help troubleshoot in production. The pipeline is designed to be adaptive and extensible so that companies can adopt it as the first step towards observability-driven development, and customize it to meet their specific requirements. / Molnbaserade applikationer blir alltmer distribuerade, komplexa och oförutsägbara med införandet av mikrotjänster och andra nya arkitektoniska komponenter. Detta resulterar i att traditionella övervakningslösningar blir alltmer inadekvata. De traditionella lösningarna tillhandahåller inte tillräcklig överskådlighet över dessa applikationer (end-to-end) för proaktiv identifiering av avvikelser från förväntat beteende innan de börjar påverka tjänsterna negativt. Som svar på dessa utmaningar föreslås observerbarhetsdriven utveckling (ODD) som en ny metod som utnyttjar verktyg och praxis för att observera tillståndet och upptäcka systemens beteende. Till skillnad från de ledande IT-jättarna som utvecklar sina egna verktyg och plattformar, har vissa icke-IT-företag och mindre organisationer fortfarande svårt att ta till sig observerbarhetsdriven utveckling. Egenutvecklad mjukvara kräver omfattande resurser och arbetskraft, medan anslutning till tredjepartsplattformar kan äventyra datasäkerheten. Den här avhandlingen bidrar med en end-to-end lösning som enbart baserats på öppen källkod. Pipelinen samlar in data från loggar och korrelerar dessa mätvärden för att underlätta mjukvaruutveckling och hjälpa till att felsöka i produktionen. Pipelinen är designad för att vara anpassningsbar och utvidgningsbar så att företag kan använda den som ett första steg mot observerbarhetsdriven utveckling och anpassa den för att möta deras specifika krav.