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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

De l'exposition professionnelle aux hydrocarbures aromatiques polycycliques à l'estimation du risque de cancers professionnels / From Occupational Exposure to Polycyclic Aromatic Hydrocarbons Mixtures to Risk Assessment of Occupational Cancers

Petit, Pascal 16 November 2016 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) constituent une famille de polluants cancérigènes, classés comme prioritaires tant en environnement qu’en milieu professionnel avec près de 1,6 millions de travailleurs exposés en France. L’évaluation des risques sanitaires (ERS) est primordiale mais reste difficile à mettre en place car ces composés sont toujours émis sous forme de mélanges complexes de gaz et de particules dont la composition varie en fonction des sources d’émission.Les objectifs de ce travail sont de caractériser, dans les différents secteurs industriels français, les expositions professionnelles (niveaux de concentration et composition chimique des mélanges) afin d’estimer les risques de cancer liés à ces expositions. Ce travail est réalisé à partir de la base Exporisq-HAP (E-HAP) qui comprend plus de 1700 données d’exposition atmosphérique ainsi que 40 variables explicatives collectées dans 130 entreprises avec la même méthodologie et codées par le même toxicologue depuis près de 20 ans.Pour conduire l’ERS, les données ont été structurées selon deux dimensions (homogénéité et précision de description), permettant de construire des groupes homogènes d’exposition (GHE) et une analyse descriptive du paysage industriel français. En prenant le benzo[a]pyrène (BaP, HAP le plus dangereux) comme indicateur, près de 40% des activités professionnelles (niveau de codage le plus fin de la base) correspondaient à des GHE (écart-type géométrique ≤ 3) mais l’ajout d’un niveau de description supplémentaire a permis d’augmenter ce pourcentage à 87%. Des variabilités importantes des niveaux de concentration, des compositions chimiques des mélanges et des risques encourus (facteur 2 pour les bitumes à 500 pour les fonderies) lors d’une mono-exposition aux HAP (e.g., BaP, naphtalène…) existaient entre et au sein des industries, soulignant l’importance de recueillir le détail des activités effectuées par le salarié pour caractériser précisément les expositions. Dans la seconde étape, les multi-expositions aux HAP ont été analysées en termes de groupes de fonction d’exposition similaire (GFES basés sur plusieurs HAP). Ces fonctions (distributions des concentrations d’HAP) ont été utilisées pour décrire le paysage industriel français aux mélanges d’HAP, construire des marqueurs de la multi-exposition atmosphérique et réaliser l’estimation préliminaire des risques de survenue de cancers. En plus du BaP, le benzo[k]fluoranthène et le benzo[ghi]pérylène sont apparus comme des indicateurs intéressants de la multi-exposition aux HAP cancérigènes, ce qui n’était pas le cas du pyrène (gazeux ou particulaire), du naphtalène ni du phénanthrène. Les GFES étaient constitués de groupes dont l’origine des sources était la même –produits dérivés de pétrole (GFESP) ou de houille (GFESH). Les GFESH (production d’aluminium, de silicium, de produits carbonés, cokeries, fonderies) avaient des niveaux de concentration élevés et un risque important de cancer du poumon (compris entre 1/100 000 à 1/1 000 de risque d’observer un cas additionnel de cancer du poumon) ; ce qui n’était pas le cas des GFESP (émissions moteurs, huiles, combustion, bitume) pour lesquels les risques de cancers sont compris entre 1/100 000 et un sur 1 million de sujets exposés. Les mesures de prévention et de protection sont encore à améliorer dans les GFESH afin de réduire les risques de survenue de cancers. / Polycyclic aromatic hydrocarbons (PAHs) are a family of organic carcinogens substances, ranked second amongst priority targeted pollutants in the environment as well as in occupational settings where around 1.6 million workers are exposed in France. Sanitary risks assessment (SRA) is paramount but remains difficult to set up considering that PAHs are always emitted in complex mixtures of gas and particles whose composition depends on emission sources.The goals of this PhD were to characterize exposures within industries (levels and chemical composition of PAHs mixtures) in order to assess the cancer risk from occupational exposure to PAHs mixtures. This work was performed using the Exporisq-HAP database (E-HAP) that gathers more than 1,700 airborne exposure data as well as 40 independent variables collected in 130 companies with the same methodology and coded by the same toxicologist for 20 years.To conduct the SRA, data were structured following two dimensions (homogeneity and description accuracy), enabling the construction of similar exposure groups (SEGs) and the descriptive analysis of the French industrial landscape. Using the benzo[a]pyrene as indicator (BaP, the most dangerous PAH), about 40% of the occupational activities (most accurate description level in E-HAP) could be considered as SEGs (geometric standard deviation ≤ 3). Adding a new description level increased this percentage to 87%. High variabilities existed between and within industries in terms of concentrations levels, chemical mixtures composition and risk (between 2 for bitumen to 500 times within foundries) caused by mono-exposure to PAHs (e.g., BaP, naphthalene…). This underlines the importance of collecting detailed information on occupational activities performed by workers to accurately describe and characterize exposures. In the second step, multi-exposures to PAHs were analyzed in terms of similar exposure function groups (SEFG based on several PAHs). Exposure functions (PAHs concentrations distributions) were used to describe the French PAHs industrial landscape, to construct markers of the multi-exposures to airborne PAHs and to perform the preliminary assessment of the cancer risk caused by these mixtures. Besides BaP, benzo[k]fluoranthene and benzo[ghi]perylene were found to be indicators of the multi-exposures to airborne carcinogenic PAHs, which was not the case for pyrene (gaseous and particulate forms), naphthalene and phenanthrene. SEFGs were made up of groups with the same source origin –either from products derived from coal (SEFGH) or petroleum (SEGFP). SEFGH (aluminum, silicon, carbon product, coke production, and foundry) had high concentration levels and high risk of lung cancer (between 100,000 to 1 risk to 1,000 to 1 risk to observe one additional case of lung cancer). It was different for SEGFP (engine emissions, lubricating oil, combustion, bitumen) that had between 100,000 to 1 risk to a million to 1 risk of additional lung cancer. To reduce cancer risks, risk management measures still need improvements in all SEFGH.
2

Analysis of 5G Edge Computing solutions and APIs from an E2E perspective addressing the developer experience

Manocha, Jitendra January 2021 (has links)
Edge Computing is considered one of the key capabilities in next generation (5G) networks, which will enable inundation of latency, throughput, and data sensitive edge-native applications. Edge application developers require infrastructure at the edge to host the application workload and network connectivity procedures to connect the application users to the nearest edge where the application workload is hosted. Distributed nature of edge infrastructure and the requirement on network connectivity makes it attractive for communication service providers (CSPs) to become Edge Service providers (ESP); similarly, hyper-scale cloud providers (HCPs) are also planning to expand as ESP building on their cloud presence targeting edge application developers. CSPs across the globe follow a standard approach for building interoperable networks and infrastructure, while HCPs do not participate in telecom standardization bodies. Standards development organizations (SDOs) such as the European Telecommunication Standardization Institute (ETSI) and 3rd Generation Partnership Project (3GPP) are working to provide a standard architecture for edge computing solution for service providers. However, the current focus of SDOs is more on architecture and not much focus on application developer experience and the Application Programming Interfaces (APIs). On the architecture itself, there are different standards and approaches available which overlap with each other. APIs proposed by different SDOs are not easily consumable by edge application developers and require simplification. On the other hand, there are not many widely known standards in the hyper-scale cloud and public cloud industry to integrate with each other except the public application programming interfaces (APIs) offered by cloud providers. To scale and succeed, edge service providers need to focus on interoperability, not only from a cloud infrastructure perspective but from a network connectivity perspective as well. This work analyzes standards defined by different standardization bodies in the 5G edge computing area and the overlaps between the standards. The work then highlights the requirements from an edge application developer perspective, investigates the deficiencies of the standards, and proposes an end-to-end edge solution architecture and a method to simplify the APIs which fulfil the need for edge-native applications. The proposed solution considers CSPs providing multi-cloud infrastructure for edge computing by integrating with HCPs infrastructure. In addition, the work investigates existing standards to integrate cloud capabilities in network platforms and elaborates the way network and cloud computing capabilities can be integrated to provide complete edge service to edge application developers or enterprises. It proposes an alternative way to integrate edge application developers with cloud service providers dynamically by offering a catalog of services. / Edge Computing anses vara en av nyckelfunktionerna i nästa generations (5G) nätverk, vilket möjliggör minskad fördröjning, ökad genomströmning och datakänsliga och kantnära applikationer. Applikationsutvecklare för Edge Computing är beroende av kantinfrastruktur som är värd för applikationen, och nätverksanslutning för att ansluta applikationsanvändarna till närmaste kant där applikationens är placerad. Även om kantapplikationer kan vara värd för vilken infrastruktur som helst, planerar leverantörer av kommunikationstjänster (CSP:er) att erbjuda distribuerad kantinfrastruktur och anslutningar. På liknande sätt planerar även molnleverantörer med hög skalbarhet (HCP) att erbjudakantinfrastruktur. CSP:er följer standardmetoden för att bygga nätverk och infrastruktur medan HCP:er inte deltar i standardiseringsorgan. Standardutvecklingsorganisationer (SDO) som europeisk telekommunikations standardiseringsinstitut (ETSI) och 3rd Generation Partnership Project (3GPP) arbetar för att tillhandahålla en standardarkitektur för Edge Computing för tjänsteleverantörer. Men nuvarande fokus är mer på arkitektur och inte mycket fokus är riktat mot applikationsutvecklares erfarenhet och API:er. I själva arkitekturen finns det olika standarder och tillvägagångssätt som överlappar varandra. API:er föreslagna av olika SDO:er är inte lättillgängliga för utvecklar av kantapplikationer och måste förenklas. Å andra sidan finns det inte många allmänt kända standarder i hyperskalära moln och offentlig molnindustri som går att integrera med varandra förutom de offentliga gränssnitten för applikationsprogrammering (API:er) som erbjuds av molnleverantörer. För att kunna betjäna omfattande applikationsutvecklare måste CSP:er erbjuda multimolnfunktioner och därmed komplettera sin egen infrastruktur med kapaciteten för HCP:er. På liknande sätt kommer HCP:er att behöva integrera anslutningstjänster utöver infrastruktur för att erbjuda kantfunktioner. Den här arbetet beskriver olika standarder definierade av olika standardiseringsorgan i Edge Computing-området för 5G, och analyzerar överlappningar mellan standarderna. Arbetet belyser sedan kraven från ett utvecklingsperspektiv av kantapplikationer, undersöker bristerna i standarderna och föreslår en lösningsarkitektur som uppfyller behovet för kantbyggda applikationer. Den föreslagna lösningen beaktar CSP:er som tillhandahåller flermolnsinfrastruktur för Edge Computing genom att integreras med HCP:s infrastruktur. Arbetet undersöker vidare befintliga standarder för att integrera molnfunktioner i nätverksplattformar och utvecklar på vilket sätt nätverks- och molntjänster kan integreras för att erbjuda kompletta tjänster till utvecklare av kantapplikationer. Arbetet föreslår ett alternativt sätt att dynamiskt integrera utvecklare av kantapplikationer med leverantörer av molntjänster genom att erbjuda en katalog av tjänster.

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