The thesis is aimed at the modeling of releases of hazardous substances to the designated software tools. The work consists of three parts. The first part is theoretical, which deals with hazardous substances and their legislation, accidents in industry, physical models of leakage and dispersion of hazardous substances and factors influencing their spread in the air and finally software tools. The second part, experimental, describes some software tools and their subsequent modeling. The third part is devoted to the results of modeling and analysis of selected software tools. The aim of the thesis is to analyze selected software tools for modeling the release of hazardous substances, to compare their explanatory power and potential use.

Les activités R&D dans le domaine d’aéronautique sont actuellement orientées par l’évolution naturelle vers des technologies plus efficaces et durables. La motivation principale de cette tendance est le besoin de résoudre les problèmes liés à la nature de l’industrie très polluante. À cet égard, le développement d’avions plus électriques contribuerait à la réduction de la consommation de combustibles fossiles en intégrant des sources et des convertisseurs d’énergie alternatifs, tels que les piles à combustibles (PàC). Cependant, un système PàC devrait se conformer à des contraintes de fiabilité et de sécurité particulières, d’autant plus que l’environnement aéronautique n’est guère clément : cyclages en pression et en température, ainsi que des forces mécaniques, agissants dans les trois dimensions. Les vibrations et les chocs peuvent notamment entraîner un desserrage brusque ou graduel de la PàC, dégradant ainsi ses performances et pouvant aller jusqu’à une fuite de gaz. Il semble donc important de pouvoir surveiller l’état de serrage mécanique d’une PàC au cours du temps, idéalement de manière non intrusive. Les résultats présentés dans la littérature indiquent que la qualité du serrage mécanique d’une PàC peut être évaluée à travers sa résistance ohmique (Rohm), plus précisément par sa partie électronique (Re-, formée par les résistances des couches de la PàC et les résistances de contact). Dans les conditions nominales de fonctionnement, l’autre partie plus importante de la Rohm – la résistance protonique (RH+, formée par la résistance de la membrane et de l’ionomère) – ne dépend pas de la force de serrage. Cette amalgamation de résistances de natures différentes empêche une extraction de la Re- sans l’utilisation de capteurs invasifs. Par conséquent, l’estimation de la qualité du serrage mécanique d’une PàC n’est pas aisée. Au cours de cette thèse, une méthode de diagnostic préventif in situ capable de détecter la dégradation des conditions de serrage d’une PàC par la modélisation de sa résistance ohmique est proposée. Une étude théorique est d’abord réalisée afin de démontrer que les résistances RH+ et Re- peuvent être séparées de la Rohm totale, à partir de leur dépendance à la température. La méthode de diagnostic est ensuite validée à l’aide de données expérimentales générées lors de la caractérisation de deux PàC à membrane échangeuse de protons : basse et haute température. Quelques divergences entre les valeurs identifiées par l’algorithme et celles rapportées dans la littérature sont observées, néanmoins, elles représentent correctement l’état du serrage mécanique de la PàC. Dans l’ensemble, les résultats sont encourageants dans le but d’estimer la qualité du serrage mécanique d’une PàC à travers l’évolution de RH+ et Re-. / The aeronautical R&D activities are currently shaped by the issues associated with the pollutantrich nature of the industry and the natural evolution towards more effective and sustainable technologies. In this regard, the development of more electric aircraft would contribute to reducing fossil fuel consumption by incorporating alternative sources and converters of energy, such as FCs. However, a FC system would have to comply with particular reliability and safety constraints, especially as the aeronautical environment is not very indulgent: abundant pressure and temperature cycling as well as mechanical loads, varying both in frequency and amplitude, in all three dimensions. Vibrations and shocks can in particular lead to a sudden or gradual loosening of the FC, thus degrading its performance, and possibly provoking a gas leak. It therefore seems important to be able to monitor the tightening state of a FC over time, ideally in a non-intrusive manner. Results reported in the literature indicate that the quality of the mechanical tightening of a FC assembly might be assessed through its ohmic resistance (Rohm), more precisely through its electronic part (Re-, formed by the bulk resistances of FC layers and the interfacial contact resistances). In nominal operating conditions, the second and more dominant part of Rohm – the protonic resistance (RH+, formed by the membrane and ionomer resistances) – does not depend on clamping pressure. This amalgamation of resistances of different natures prevents an easy extraction of Re- without the use of invasive sensors and thus an estimation of the quality of the mechanical tightening of a FC assembly. This thesis proposes an in situ preventive diagnosis method that is capable of detecting the degradation of clamping conditions of a FC through the modelling of its ohmic resistance. A theoretical study is performed and demonstrates that the RH+ and Re- resistances can be separated from the total Rohm, based on their temperature dependence. The proposed method is verified with experimental data generated during the characterization of low and high temperature Polymer Electrolyte Membrane (PEM) single cells. Although some differences between the values identified by the algorithm and those reported in the literature are observed, they correctly depict the behavior of the mechanical tightening of the tested FCs. Overall, the results are encouraging in the aim of monitoring the quality of mechanical tightening of a FC through the evolution of RH+ and Re-.

In a world of the Internet of Things, smart home has shown a great potency and trend. A smart home is a convenient home setup where appliances and devices can be automatically controlled remotely from any internet-connected place in the world using a mobile or other networked device. Smart home has changed the way the residents interacted with their home and realised more convenience. Although this technology also has positive impact on saving energy and resources, privacy issues in it have shown to one of the biggest obstacles to the adaption of this technology. The purpose of this thesis is to study smart home users’ perceptions of smart homes and their privacy awareness and concerns. The research was conducted through interviews and followed an interpretive research paradigm and a qualitative research approach. In this study, 5 smart home owners were interviewed to investigate their reasons for purchasing IoT devices, their perceptions of smart home privacy risks, and actions to protect their privacy, as well as managing IoT devices and/or its data. The research results show that there are privacy risks existing in smart homes. Consumers’ privacy data is collected secretly, which needs to be controlled, and privacy issues have to be addressed in the near future for the smart home to be fully adopted by the society.

Cette thèse traite des problèmes de fuite de données accidentelles au sein des entreprises. Ces fuites peuvent être dues à l’utilisation conjointe de politiques de Contrôle d’Accès (CA) et de Contrôle de Transmission (CT). De plus, l’utilisation conjointe de ces deux types de politique génère plusieurs problèmes pour les personnes ayant la charge de créer et maintenir ces politiques. Parmi ces problèmes, nous pouvons citer des problèmes de généricité des modèles existants, de cohérence entre les règles de CA et de CT ainsi que des problèmes de densité, d’adaptabilité, d’interopérabilité et de réactivité. Dans cette thèse, nous proposons en premier lieu un méta-modèle pour prendre en compte la plupart des modèles de CA utilisés dans les entreprises. Nous proposons ensuite la génération cohérente et semi-automatique des politiques de CT à partir de politiques de CA existantes pour répondre au problème de cohérence. De plus, différentes fonctionnalités sont proposées pour résoudre les problèmes de densité, d’adaptabilité et d’interopérabilité. Afin de valider la pertinence de notre solution, nous proposons une étude (type questionnaire) auprès d’experts sécurité et d’administrateurs. Cette étude révèle des informations sur la taille des politiques gérées, la pénibilité à les définir ou encore l’utilité des fonctionnalités proposées pour résoudre les problèmes précédents. Enfin, nous testons notre preuve de concept sur des données aléatoires et réelles en prenant en compte les performances et la réactivité, validant ainsi que notre solution répond bien aux problèmes soulevés. / The main objective of this thesis is to solve the problem of unintentional data leakage within companies. These leaks can be caused by the use of both Access Control (AC) and Transmission Control (TC) policies. Moreover, using both AC and TC can lead to many problems for the security experts and the administrators that are in charge of the definition and maintenance of such policies. Among these problems, we can underline the genericity problem of existing models, the coherence problem between AC and TC rules and problems such as density, adaptability, interoperability and reactivity. In this thesis, we first define a meta-model to take into account the main AC models that are used within companies. We also propose a coherent and semi-automatic generation of TC policies based on existing AC to tackle the coherence problem. Moreover, several mechanisms have been proposed to tackle complexity, adaptability and interoperability issues. In order to validate the relevance of our solution, we have first conducted a survey among security experts and administrators. This survey has highlighted several information regarding the policies’ size and density, the tiresomeness of having to define them and the interest for several functionalities that can cover the aforementioned problems. Finally, our solution has been tested on stochastically generated and real policies in order to take performances and reactivity under consideration. Results of these tests have validated that our solution covers the underlined problems.

The dissertation thesis deals with short-term gas releases (puffs) in an urban canopy studied utilizing wind-tunnel modelling. The urban canopy was composed of buildings with pitched roofs organised into closed courtyards. Into it, a ground-level point gas source was placed. The first part of the thesis is focused on specific definitions of puff characteristics. New definitions of puff arrival and departure times are presented. Various definitions of puff arrival time were applied on the same datasets and the results were compared. Moreover, it was studied how slight changes in determination of puff departure time can affect its values and other derived puff characteristics. The second part of the thesis is focused on modelling of probability density functions of puff characteristics with knowledge of sampling positions towards the gas source and mean values of concentrations valid for long-term gas sources. The found equations will be utilized in an operational model. The outputs in the form of the probability density functions of puff characteristics distinguish my model from the usually utilized operational models, in which only the ensemble-averaged puff outline and concentration field can be predicted.

Detta examensarbete har genomförts med anledning av att Norrvatten har önskemål om att få en rapport om de material som används i deras vattenledningsnät med fokus på typiska skador kopplade till ett specifikt material eller tillverkningsmetod. Det har framkommit indikationer om att kunskapen om rörmaterial och dess egenskaper med tiden har försämrats då den äldre generationens projektörer efterlämnat en kunskapslucka efter sig. Syftet med rapporten är att ge en god överblick av materialen i Norrvattens ledningsnät. Det krävs kunskap om materialen för att analysera sambandet mellan läckningsstatistik och materialets egenskaper. Informationshalten varierar mellan de olika materialen. Detta beror framförallt på materialets uppbyggnad och svårighetshalten att redovisa en klar och rättvis bild över dem. Materialen och dess information är uppdelade i kapitel för att underlätta för läsaren att på ett enkelt sätt förstå sammanhangen. Ett annat viktigt kapitel i denna rapport är beskrivningen över de anläggningsmetoder som valdes att tas med, dels markförlagda ledningar men också två schaktfria metoder vilka är infodring och rörspräckning. I verkligheten finns det många fler utbytesalternativ än dem som tas upp i rapporten, men många metoder är snarlika och dem som redovisas tillhör de vanligaste arbetssätten. Detta kapitel är direkt knutet till dimensioneringsverktyget för utbytesmetoderna med avseende på hållfasthet från jordtryck samt trafiklaster, men också dragspänningar som uppstår i framförallt de schaktfria metoderna. Dimensioneringsverktyget består av ett Excel-dokument där användaren med grundläggande parametrar fyller i dokumentet för att sedan få resultat huruvida den nylagda ledningen klarar de påfrestningar som den utsätts för. Baserat på ledningsanvändning mellan olika material och jämföra mot dess skadestatistik vill vi ge en god slutsats om vilket material som vi anser, generellt sett, är lämpligast att använda sig utav. / This thesis has been conducted in response to a request by Norrvatten for an objective report concerning the materials used in their water supply infrastructure, with a focus on the typical damages linked to specific materials or manufacturing processes. Through interviews with well-informed experts we have received indications that the knowledge regarding the materials used in Norrvatten’s water pipes and said materials’ properties have declined over time, as the older generation of construction planners have left behind a knowledge gap. The purpose of the report is to give a good insight into the materials used in Norrvatten’s water supply infrastructure (specifically the pipes used). We claim that a knowledge of the materials used is necessary to analyze the correlation between leakage statistics and the properties of the materials used in the infrastructure. The level of information available varies between the different materials. This is mainly caused by the structure of the material and the difficulty in depicting a clear and objective picture of it. The materials and their information are divided into separate chapters to make it easier for the reader to understand the picture we are trying to create. Another important chapter in this report is the description of the methods of installation we have chosen to work with; these methods are buried pipelines but also two trenchless methods which are lining and pipe bursting. In reality many more methods that the ones described here exist, but many methods are similar and the ones presented here are those that are most commonly used. This chapter is directly linked to our dimensioning model for pipe replacements concerning strength in regard to earth pressure and traffic load, but also the tensile that occur primarily in the trenchless methods. The dimensionality model is constructed as an Excel document where the user – through utilizing some basic parameters – fills out the document and automatically receives results regarding whether or not the new pipes will withstand the stress it is exposed to. Based on the correlation between damage statistics and the use of different materials in the pipe infrastructure we attempt to provide an accurate picture of which materials we deem to be, generally speaking, the most appropriate to make use of.

The conductivity is one of the main properties of HVDC cable insulation materials and needs to be evaluated carefully. Since measurement on cables is time consuming, often thin specimens and normal conductivity measurement cells are used to compare the materials. In this way however, the bulk effects will be less represented in the measurement and the results will be less representative. Instead, one needs to perform the measurements on thick plate samples and with higher voltage levels. This work focuses on the conductivity measurements on thick HVDC insulation plate samples subject to a high electric field and carefully controlled conditions. In the literature, there are many different methods of measuring the leakage current such as dielectric spectroscopy, PD, IV and PEA measurements. In this thesis a three electrode setup is used to measure the leakage current where the electrodes are placed inside the oven.  This is to be able to control both temperature and high voltage under similar and different conditions where it is possible to change these two parameters during measurement. This was made by two Labview programs; one for creating a schedule and one control program which controls the equipment in the cell.  The task was to make sure that the cell functioned by obtaining repeatable and reasonable measurements.  The results that were obtained were reasonable and verified that the cell functioned. The executed measurements were performed in order to achieve a better understanding of error factors in the measurement system, ranging from preparing the sample to measuring the leakage current. The purpose with the cell is it to investigate the quality of the HVDC insulation by conductivity measurements on millimetre thick plate samples. / Den elektriska konduktiviteten är en av de viktigaste egenskaperna av HVDC kablars isolationsmaterial, XLPE, och den måste utvärderas noggrant. Mätning på fullskaliga kablar är tidskrävande och för att jämföra material används istället ofta tunna prover och normerade konduktivitetmätningsceller. En nackdel med denna metod är att bulkeffekterna blir mindre framträdande i mätningen och resultaten kommer att vara mindre representativa. Istället måste man utföra mätningen på tjockare prover och vid högre spänning. Detta examensarbete fokuserar på mätning av ledningsförmåga hos tjocka HVDC- isolationsprover under noggrant kontrollerade förhållanden och starka elektriska fält. I litteraturen finns det många olika metoder att mäta läckströmmar på, till exempel dielektrisk spektroskopi, PD, IV och PEA mätningar för att nämna några. I denna avhandling kommer ett tre-elektrod system att användas där en temperatursensor är monterad på ena elektroden. Systemet används för att både mäta läckströmmar och temperatur vid provet. Detta gör det möjligt att kontrollera temperatur och spänning oberoende av varandra vilket gjordes med hjälp av två Labview program. Det ena för att skapa ett schema och det andra användes som kontrollprogram för att styra utrustningen i cellen. Uppgiften var att kontrollera cellens funktion genom att erhålla rimliga repeterbara mätningar. Mätningarna gav rimliga resultat vilket indikerade att cellen fungerar tillfredställande. Syftet med mätningarna var att få en bättre förståelse för felfaktorer i mätsystemet som kan vara allt från att förbereda provet till att mäta läckström. Syftet med cellen är att undersöka isolationsegenskaperna på millimetertjocka pressade XLPE prover.

Le crowdsourcing est une pratique permettant aux entreprises de faire appel à l’intelligence humaine à grande échelle afin d’apporter des solutions à des problématiques qu’elles souhaitent externaliser. Les problématiques externalisées sont de plus en plus complexes et ne peuvent être résolues individuellement. Nous proposons dans cette thèse une approche appelée SocialCrowd, contribuant à améliorer la qualité des résultats de crowdsourcing. Elle consiste à faire collaborer les participants afin d’unir leur capacité de résolution et apporter des solutions aux problèmes externalisés de plus en plus complexes. Les groupes collaboratifs sont mis en compétition, via des rétributions attrayantes, afin d’obtenir de meilleures résolutions. Par ailleurs, il est nécessaire de protéger les données privées des groupes en compétition. Nous utilisons les réseaux sociaux comme support de fuite de données. Nous proposons une approche basée sur l’algorithme Dijkstra pour estimer la probabilité de propagation de données privées d’un membre sur le réseau social. Ce calcul est complexe étant donné la taille des réseaux sociaux. Une parallélisation du calcul est proposée suivant le modèle MapReduce. Un algorithme de classification basé sur le calcul de propagation dans les réseaux sociaux est proposé permettant de regrouper les participants en groupes collaboratifs et compétitifs tout en minimisant les fuites de données d’un groupe vers l’autre. Comme ce problème de classification est d’une complexité combinatoire, nous avons proposé un algorithme de classification basé sur les algorithmes d’optimisation combinatoires tels que le recuit simulé et les algorithmes génétiques. Etant donnée le nombre important de solutions possible, une approche basée sur le modèle du Soft Constraint Satisfaction Problem (SCSP) est proposée pour classer les différentes solutions. / Crowdsourcing is the practice of allowing companies to use human intelligence scale to provide solutions to issues they want to outsource. Outsourced issues are increasingly complex and cannot be resolved individually. We propose in this thesis an approach called SocialCrowd, helping to improve the quality of the results of crowdsourcing. It compromise to collaborate participants to unite solving ability and provide solutions to outsourced problems more and more complex. Collaborative groups are put in competition through attractive remuneration, in order to obtain better resolution. Furthermore, it is necessary to protect the private information of competing groups. We use social media as a support for data leakage. We propose an approach based on Dijkstra algorithm to estimate the propagation probability of private data member in the social network. Given the size of social networks, this computation is complex. Parallelization of computing is proposed according to the MapReduce model. A classification algorithm based on the calculation of propagations in social networks is proposed for grouping participants in collaborative and competitive groups while minimizing data leaks from one group to another. As this classification problem is a combinatorial complexity, we proposed a classification algorithm based on combinatorial optimization algorithms such as simulated annealing and genetic algorithms. Given the large number of feasible solutions, an approach based on the model of Soft Constraint Satisfaction Problem (SCSP) is proposed to classify the different solutions.

No description available.

Mountain biking is a sport where riders bike on trails, varying in slope and difficulty. Mountain bikes are generally equipped with suspension on the front wheel and often also on the rear. Some types of rear shocks use pressurized air for a spring action instead of the traditional metal coil. Air is sealed inside the shock’s air can by means of X-ring seals, providing a spring force on the wheel. It is of great importance that the sealing system performs as intended so the air spring does not quickly lose pressure during use. An experimental plan is conducted in an attempt to estimate the effects of seal dimension, lubrication and surface roughness on air leakage for more robust shocks. Accelerated tests were performed in a dynamometer, believed to repeatedly cause significant wear on the shock’s air seal within 24 hours. Nineteen tests were carried out, for a duration up to 72 hours, with variations to test parameters such as stroke length and frequency. The expected failure modes did not occur in any of them. Eleven tests showed no signs of failure while the other eight failed due to unexpected components breaking or wearing out. The shock’s main seal was found to wear out faster than the air seal, causing leakage within the air spring, between its positive and negative air chambers. This unforeseen failure needs further examination with tests conducted on more shock types. / Mountainbike är en sport där utövare åker på stigar med varierande lutning och svårighet. Terrängcyklar är generellt utrustade med stötdämpare eller fjädrar på framhjulet och ofta också på bakhjulet. Vissa terrängcyklar har stötdämpare bak som använder trycksatt luft för att dämpa istället för att använda traditionella stålfjädrar. Luften är sluten inuti stötdämparen med hjälp av X-rings tätningar, vilket ger en fjäderkraft på hjulet. Det är viktigt att tätningen fungerar så att luftfjädern inte snabbt tappar trycket när den används. En experimentplan skapades i ett försök att uppskatta effekten av tätningsdimension, smörjning och ytjämnhet på luftläckage för mer robusta stötdämpare. Accelererade tester gjordes i en dynamometer, som troddes kunna skapa signifikant slitage på en stötdämpares tätning inom 24 timmar upprepade gånger. 19 test gjordes med en körtid på upp till 72 timmar med variation av testparametrar som slaglängd och frekvens. De förväntade felkällorna uppstod inte i något av testerna. 11 tester visade inga tecken på fel medan 8 tester misslyckades på grund av att oväntade komponenter slets ut eller gick sönder. Stötdämparens huvudtätning visade sig slitas fortare än lufttätningen, vilket resulterade i läckage inuti luftfjädern mellan dess positiva och negativa kammare. Detta oförutsedda fel behöver vidare undersökning med tester på fler olika typer av stötdämpare.