This study investigated the corrosion processes at the top and bottom of carbon steel pipelines transporting wet gases, and studied possible chemical mitigation strategies. First, immersion tests were carried out using carbon steel to study the effects of de-aeration with high purity nitrogen gas on the corrosion rate. Secondly, the corrosion rate was assessed for varying chloride ion concentrations in an aerated environment. In general, increasing de-aeration time changes the corrosion mechanism from mass transfer oxygen reduction to water reduction reaction. However, oxygen solubility controlled the corrosion process in aerated solution containing different chloride ion concentrations. A special two-electrode cell was designed for the top of the line corrosion (TLC) electrochemical measurements but a conventional three electrode cell was used for the bottom of the line corrosion (BLC) measurements. The TLC rate increases with temperature, and X-Ray Diffraction (XRD) confirmed the presence of chukanovite {Fe2(CO3)(OH)2}and possibly ferrous carbonate corrosion products at 40oC and 60oC respectively. However, for the BLC, the cementite phase remained on the metal surface after preferential dissolution of the ferrite phase in the carbon steel. Addition of acetic acid (HAc) locally dissolved the initially FeCO3 film formed on the metal surface, causing local corrosion damage. Addition of methyl di ethanol amine (MDEA) as a pH stabiliser reduced TLC and BLC rates due to enhanced stability of FeCO3 at pH 5.7-6.3. When Zn2+ ions were added as ZnCl2, both Fe2O3 and ZnCO3 were formed at reduced corrosion rate. Whenever FeCO3 film was damaged/dissolved by HAc addition of neither pH stabiliser; MDEA nor hydrate preventer; mono ethylene glycol (MEG) could not re-establish a protective film on the metal surface. The following organic inhibitors were investigated as potential mitigators of TLC: 2-mercaptobenzimidazole (2MBI), 2-amino-5-ethyl-1,3,4-thiodiazole (AETDA), 2-phenyl-2-imidazoline (2PI), dicyclohexylamine (DHA), and a commercial inhibitor formulation (CI-A). The inhibition efficiency (IE%) was found to increase in the order CI-A > 2MBI > AETDA > DHA. Their efficiency increases (except DHA) with inhibitor concentrations both at top and bottom of the line. 2MBI and CI-A behaved as mixed inhibitors but AETDA behaved as cathodic inhibitor, all were best fitted to a simple Langmuir adsorption isotherm. However, IE% of DHA decreased at higher inhibitor concentrations. Surprisingly, 2PI inhibitor increased the corrosion rate, and the corrosion rate further increased with increase inhibitor concentrations. Weight loss measurements results of TLC are also presented which showed lower inhibition efficiency for all the inhibitors investigated compared with electrochemical measurements in similar environments. The free energy of adsorption (∆Goads values for 2MBI and AETDA are around -36kJ.mol-1 while for CI-A the value was -15kJ.mol-1 (-7kJ.mol-1 in the presence of HAc). This is evidence for adsorption of 2MBI and AETDA on the metal surface by chemisorption with CI-A by physisorption. XPS analysis confirmed the presence of FeCO3 and FeOOH as corrosion products in the brine solution in the absence and presence of HAc containing different corrosion inhibitors.

According to the predictive coding approach to perception, the brain uses predictions based on previous experience to optimise perception, by allocating more computational resources to important or unexpected stimuli. Overall, predictions allow faster and more accurate recognition, but occasionally, when the prediction is incorrect, it may lead to a misperception. The aim of this thesis was to investigate the influence of top - down processes on perceptual decisions. I utilised misperceptions as a signature of those top - down influences and Signal Detection Theory to assess their size, type and direction. I used Electroencephalography to determine the stage of information processing at which different types of predictions influence sensory processing.The empirical studies are clustered around Topic 1: Influence of Predictions on Perception, Topic 2: Types of Predictions and Topic 3: Value as Modulator of Perception.Studies clustered in Topic 1 analysed and quantified the influence of predictions on perceptual decisions and showed that misperceptions can be triggered by wrong predictions only in very specific circumstances. In particular, misperceptions occurred only if there was some degree of correspondence between the wrong prediction and the sensory input. Otherwise, predictions were easily rejected, increasing the overall accuracy. I also demonstrated that misperceptions were most likely to happen in a window on the continuum of input quality where the stimulus - related uncertainty was highest. Topic 2 comprised experiments investigating different types of predictions and their interaction. Behavioural (but not EEG) results revealed interference between passive and active expectations. The early event related (ERP) components N1 and P2, as well as the P300, were all modulated by expectations. Expected events either increased or decreased the P300 amplitude, depending on whether the expected item was predictable and thus ignored, or awaited and thus flagged for further processing. This suggests that P300 might be an index of top - down resource allocation. Experiments within Topic 3 studied the influence of values, as examples of executive processes, on perceptual decisions, using either natural or acquired high - value stimuli. The results suggested that the process of recognition is adjusted in a top - down manner to account for the cost and benefit values related to different outcomes. The trade - off between processing time and accuracy is not fixed, but can be adjusted to optimise recognition in the task at hand. Furthermore, value can change the focus of perception, resulting in different elements of the sensory input being amplified or ignored. Overall, these results showed that misperceptions are 'intelligent mistakes' - a by - product of a top-down, prediction - based optimisation strategy that decreases the computational load, while increasing accuracy and improving the allocation of computational resources.

Recent research has investigated the moderating effects of environmental characteristics on the relationships between top management team heterogeneities and firm performance but has given little attention to the moderating role of board composition. This study examines the moderating effects of the proportion of outside board membership on the relationships between top management team heterogeneities and firm performance. The upper echelons theory would contend that outside directors with their valuable resources (information, skills, and network) and the tendency to challenge and initiate cognitive conflicts with top management teams can improve the quality of strategic decision making process and firm performance. To test these predictions, it is hypothesized that the greater the proportion of outside directors, the more positive the relationship between top management team tenure heterogeneity, educational heterogeneity, functional background heterogeneity, and firm performance. Fortune 500 companies were chosen as the sample of the study. I utilized moderated hierarchical regression to analyze the data. The results do not support the predictions. Several theoretical and methodological issues are discussed.

Purpose – The purpose of the study is to map out the top-down and bottom-up perspectives and investigate the information strategies on how it relates to daily operations in three case companies. To fulfill the purpose, the following three questions have been answered:   What approach do the organization have on information strategies and what  characterizes them? To what extent do the case organization use the information strategies?   What opportunities and difficulties do organizations see with the information strategies?   Method – To fulfill the purpose, a case study was carried out on three case companies. The empirical data has been collected through interviews and surveys. The theoretical framework together with the empirical data, has then contributed to achieving the purpose.   Findings – First the map out was conducted within three case companies and how the information strategies have been chosen in relation to the daily operations perspective. Based on the mapping, it has then been framed the potential possibilities and difficulties with the respective strategy choices and its implementation. Limitations – The definition of the information strategies within the study is defined as Top-down and Bottom-up and how the choice in how companies choose to coordinate and be responsible for tasks. The authors do not know whether the study can be adapted to the business of other organisations when mapping information strategies.   Keywords – information strategies, top-down, bottom-up, information flow, communication.

This dissertation explores the effectiveness and consequences of three distinct education policies. The first chapter analyzes the effects of high school exit exams on graduation, employment and wage outcomes. We construct a state-graduation year cohort dataset using the Current Population Survey data, US Census data and information on the timing and difficulty of exit exams in different states. Using this dataset we analyze within-state variation in outcomes overtime. Overall, we find relatively modest effects of high school exit exams. We do not find consistent effects on graduation rates for exit exams that assess academic skills taught below the high school level; however, we find that more challenging standards-based exams reduce graduation rates. We also find that about one-half of the reduction in graduation rates associated with exit exams is offset by an increase in GED rates. Our analysis of labor market outcomes suggests that exit exams increase employment rates, but we find no effect of exit exams on the distribution of wages. Chapter two analyzes the institutional consequences of the California Class-Size Reduction (CSR) program. This program provides incentive funding if schools limit the class-size in grades K-3 to twenty or fewer students. We find that some schools and school districts limit their enrollment levels in order to maximize the CSR subsidy payment. In particular, the distribution of grade and district enrollments exhibits a prominent pattern of peaks that occur at multiples of twenty, where CSR payment is the largest. In order to achieve exact enrollment levels, schools must be reassigning students above the desired thresholds to nearby schools or nearby school districts. We also find that schools that limit their enrollments are well-performing schools with a low percentage of students who receive free or reduced price meals. The last chapter analyzes the academic consequences of the Texas Top 10 Percent Law. In 1998, state universities in Texas began using high school class rank as the sole factor in university admissions. This policy was implemented to increase enrollment of minority and economically disadvantaged students, but it generated criticism that such beneficiaries of rank-based admissions lack the academic preparation necessary to perform well in college. I test this claim by analyzing academic performance of rank-eligible students who attended UT Austin before and after the law. To account for grade inflation I use a difference-in-differences framework with students not eligible for rank-based admissions as controls. The difference-in-differences estimates may be overstated, however, because academic quality of the control group may have increased after the law. I use propensity score matching methods to correct for this. Finally, I correct for the confounding effects of GPA ceiling on the difference-in-differences estimates. Both the baseline and the adjusted estimates suggest that mean college GPA of rank-admitted students declined after the law.

Ces dernières années ont connu un regain d'intérêt pour l'utilisation des graphes comme moyen fiable de représentation et de modélisation des données, et ce, dans divers domaines de l'informatique. En particulier, pour les grandes masses de données, les graphes apparaissent comme une alternative prometteuse aux bases de données relationnelles. Plus particulièrement, le recherche de sous-graphes s'avère être une tâche cruciale pour explorer ces grands jeux de données. Dans cette thèse, nous étudions deux problématiques principales. Dans un premier temps, nous abordons le problème de la détection de motifs dans les grands graphes. Ce problème vise à rechercher les k-meilleures correspondances (top-k) d'un graphe motif dans un graphe de données. Pour cette problématique, nous introduisons un nouveau modèle de détection de motifs de graphe nommé la Simulation Relaxée de Graphe (RGS), qui permet d’identifier des correspondances de graphes avec un certain écart (structurel) et ainsi éviter le problème de réponse vide. Ensuite, nous formalisons et étudions le problème de la recherche des k-meilleures réponses suivant deux critères, la pertinence (la meilleure similarité entre le motif et les réponses) et la diversité (la dissimilarité entre les réponses). Nous considérons également le problème des k-meilleures correspondances diversifiées et nous proposons une fonction de diversification pour équilibrer la pertinence et la diversité. En outre, nous développons des algorithmes efficaces basés sur des stratégies d’optimisation en respectant le modèle proposé. Notre approche est efficiente en terme de temps d’exécution et flexible en terme d'applicabilité. L’analyse de la complexité des algorithmes et les expérimentations menées sur des jeux de données réelles montrent l’efficacité des approches proposées. Dans un second temps, nous abordons le problème de recherche agrégative dans des documents XML. Pour un arbre requête, l'objectif est de trouver des motifs correspondants dans un ou plusieurs documents XML et de les agréger dans un seul agrégat. Dans un premier temps nous présentons la motivation derrière ce paradigme de recherche agrégative et nous expliquons les gains potentiels par rapport aux méthodes classiques de requêtage. Ensuite nous proposons une nouvelle approche qui a pour but de construire, dans la mesure du possible, une réponse cohérente et plus complète en agrégeant plusieurs résultats provenant de plusieurs sources de données. Les expérimentations réalisées sur plusieurs ensembles de données réelles montrent l’efficacité de cette approche en termes de pertinence et de qualité de résultat. / Recent years have witnessed a growing renewed interest in the use of graphs as a reliable means for representing and modeling data. Thereby, graphs enable to ensure efficiency in various fields of computer science, especially for massive data where graphs arise as a promising alternative to relational databases for big data modeling. In this regard, querying data graph proves to be a crucial task to explore the knowledge in these datasets. In this dissertation, we investigate two main problems. In the first part we address the problem of detecting patterns in larger graphs, called the top-k graph pattern matching problem. We introduce a new graph pattern matching model named Relaxed Graph Simulation (RGS), to identify significant matches and to avoid the empty-set answer problem. We formalize and study the top-k matching problem based on two classes of functions, relevance and diversity, for ranking the matches according to the RGS model. We also consider the diversified top-k matching problem, and we propose a diversification function to balance relevance and diversity. Moreover, we provide efficient algorithms based on optimization strategies to compute the top-k and the diversified top-k matches according to the proposed model. The proposed approach is optimal in terms of search time and flexible in terms of applicability. The analyze of the time complexity of the proposed algorithms and the extensive experiments on real-life datasets demonstrate both the effectiveness and the efficiency of these approaches. In the second part, we tackle the problem of graph querying using aggregated search paradigm. We consider this problem for particular types of graphs that are trees, and we deal with the query processing in XML documents. Firstly, we give the motivation behind the use of such a paradigm, and we explain the potential benefits compared to traditional querying approaches. Furthermore, we propose a new method for aggregated tree search, based on approximate tree matching algorithm on several tree fragments, that aims to build, the extent possible, a coherent and complete answer by combining several results. The proposed solutions are shown to be efficient in terms of relevance and quality on different real-life datasets

Ce travail vise à la mise en œuvre d'une plateforme de simulation basée sur SystemC-AMS. Elle permet de traiter un système complexe et hétérogène. Nous validons cette approche sur une application de réseau de capteurs (communication entre véhicule). Pour ce faire un niveau d'abstraction élevé a été adopté et une modélisation en bande de base des blocs RF a été développée. Non seulement les aspects relatifs à l'émetteur/récepteur ont été traités, mais également le canal radio.Si les actuels flots de conceptions permettent d'estimer la consommation des blocs numériques d'un SoC, une méthodologie d'estimation de la consommation des blocs analogiques et RF n'est toujours pas disponible. Nous proposons une méthodologie descendante basée sur le facteur de mérite et les paramètres systèmes pour estimer la consommation instantané de ces blocs. Ainsi des estimations de la consommation globale des nœuds et du réseau sont fournies par la plateforme.Nous avons fourni une bibliothèque implémentée en SystemC-AMS pour différents blocs d'un réseau de capteurs (nœud et canal radio). Les résultats montrent la faisabilité d'une simulation complexe mixte analogique, numérique et RF. Par ailleurs, ils montrent le gain considérable apporté par la simulation au niveau système en SystemC-AMS de modèles comportementaux d'un réseau de capteurs. La plateforme développée dans ce travail ouvre diverses perspectives sur de nombreux et importants aspects de la simulation système des réseaux de capteurs. Parmi ces aspects, le choix et l'optimisation des algorithmes de routage, les protocoles MAC, les algorithmes de traitement du signal sous une contrainte de consommation d'énergie. / This work aims at implementing a simulation platform based on SystemC-AMS. It can handle a complex and heterogeneous system on chip (SoC). An application of wireless sensor network (WSN): inter-vehicle communication is used to validate this approach. To realize this application, a high level of abstraction was adopted and a baseband modeling of RF blocks has been developed. Besides, not only aspects related to the RF transceiver, but also the radio channel were studied.The current design flows enable the estimation of power consumption of digital blocks, however a high-level methodology for power consumption estimation of analog and RF blocks is still not available. We propose a Top-Down methodology based on the figure of merit (FoM) and system parameters to estimate the instantaneous power consumption of these blocks. Thus, estimates of overall consumption of nodes and the WSN are provided by the platform.We delivered a library implemented in SystemC-AMS for different blocks of a WSN such as node and radio channel. The results show the feasibility to simulate complex, RF and analog mixed SoC. In addition, they show the significant gain in terms of simulation time provided by the system-level simulation using SystemC-AMS and behavioural models of WSN.The platform developed in this work opens a variety of perspectives on many important aspects of system-level simulation of WSN. These aspects include the choice and optimization of routing algorithms, MAC protocols, signal processing algorithms, as a function of power consumption which is the main constraint of WSN.

In comparison with other Muslim Arabic countries, Tunisia have attained a unique and successful progress when it comes to women’s rights and gender equality. According to researchers, the progress of women’s rights in Tunisia is due to a policy of top down State feminism that the country has adapted since the independence from the French colonialism 1956. Researchers have mainly focused on investigating the diverse factors that contributed to this progress and on tracing the causal mechanism behind the unique women’s legal rights in Tunisia. Nevertheless, there are few studies that carefully examined gender norms in Tunisian society and its relation to the adopted top down State feminism. The goal of this thesis is to analyse how gender norm are described in Tunisians legal texts and compare it to how young educated citizens in Tunisia relate to gender norms, as well to see if there are any eventual potential progress regarding gender equality in the future in Tunisia. This thesis is based on text analysis of law texts and qualitative group interviews. This thesis has no high explanatory ambitions, but it seeks to illustrate the various potential explanations for the differences and similarities between how gender norms are constructed in law texts and among young educated citizens in Tunisia. Also, this thesis seeks to obtain an idea about how these differences and similarities can be understood. This was done with the help of the data collected from the group interviews and also using theories about State feminism and the relation between the state and gender norms. The analysis of law texts shows that the Tunisian state draws a rigorous line between the public and the private sphere. The Tunisian state expresses a progressive view regarding gender norms on the public sphere but a conservative one when it comes to the private sphere. The interviewees’ views regarding gender norms in the public and the private sphere can be divided into two main categories depending on how they argument for their point of view: “Progressive” and “Conservative”. Thus, differences and similarities between how gender norms are expressed in law texts and by the participants in this study and how those can be understood, depends on which ideologies and mindsets the participants have concerning gender norms. Thus, the cultural and religious heritage as well as the social current circumstances can be assumed to be one of the most crucial factors that affects the progress of gender norms and equality in the public sphere likewise the private sphere in the case of Tunisia. / Jämfört med andra arabiska muslimska länder har Tunisien genomgått en märkbar och annorlunda utveckling vad gäller jämställdhet och kvinnors rättigheter. Enligt forskning på området berodde detta huvudsakligen på en top down State feminism policy som landet har anammat sedan självständigheten från den franska kolonialismen 1956. Forskare har mest fokuserat på att undersöka de olika faktorer som ledde till denna framgång och den kausala mekanismen bakom kvinnors unika juridiska rättigheter i Tunisien. Det är dock få forskare som har ägnat sig åt att studera genusnormer i det tunisiska samhället och dess relation till denna top-down State Feminism. Syftet med denna uppsats är att analysera hur lagtexter I Tunisien skildrar genusnormer och jämföra det med hur unga utbildade tunisier förhåller sig till genusnormer samt att se om det verkar finnas en potential för en framtida förändring vad gäller jämställdhet i Tunisien. Denna uppsats är baserad på textanalys av lagtexter samt kvalitativa gruppintervjuer med unga universitetsutbildade i Tunisien. Uppsatsen har inga höga förklarande ambitioner men ämnar snarare att, med hjälp av intervjumaterialet samt teorier kring State feminism och relationen mellan staten och genusnormer, kasta ljus på de potentiella förklaringarna till hur eventuella skillnader och likheter mellan lagtexters och ungas syn på genusnormer kan förstås. Analysen av lagtexter visar att staten i Tunisien drar en strikt linje mellan den offentliga och privata sfären. Staten uttrycker en progressiv syn på genusnormer i den offentliga sfären men en konservativ syn i den privata. Hur deltagare i denna studie ser på genusnormer i den offentliga och den privata sfären kan egentligen delas i två kategorier beroende på hur de argumenterade för sina synpunkter: ”Progressiva” och ”Konservativa”. Således beror vilka eventuella skillnader och likheter som finns mellan gennusnormer som uttrycks i lagtexter och bland unga i denna studie samt de potentiella förklaringarna till dessa skillnader och likheter, på vilket tankesättet deltagarna tillhör. Det kulturella och religiösa arvet samt samhällets omständigheter och behov kan antas dock vara bland de mest betydelsefulla faktorerna för genusnormers utveckling och jämställdhet både inom lagen och i samhället i just fallet Tunisien.

All kinds of products have economic, social and environmental impact throughout their entire life cycle. Today’s growing need for electronic devices contributes to the increasing problem within these fields.  The aim of this study is to investigate and determine the impact of a chosen Teracom Group product from a sustainability perspective and to develop recommendations regarding how to proceed, in order to reduce the impact of products. This study is mainly focusing on the environmental aspect of the concept of sustainability. A life cycle assessment (LCA) of a set-top box (STB) is conducted based on chosen indicators by using the software SimaPro. The goal of the assessment is to identify the phases within the life cycle with largest environmental impact and contribute to Teracom Group’s further sustainable work. 18 impact categories are included to express emissions and use of natural resources. The result clearly shows that the production phase has the largest environmental impact within categories such as terrestrial acidification, human toxicity, freshwater ecotoxicity, marine ecotoxicity, urban land occupation and metal resource depletion. The use phase affects the environment foremost within climate change, ozone depletion, terrestrial ecotoxicity, ionising radiation, agricultural land use, natural land transformation and water depletion. Transports and the waste scenario only have a small effect on certain categories. The experiences of this study are discussed, demonstrating the difficulty in making an LCA in the position of being at the company purchasing products, not at the company manufacturing them. The company has previously not focused enough on sustainability regarding products. An LCA performed by the supplier would be more reliable due to a better possibility of collecting accurate data. Communication and cooperation between the company and its suppliers are key solutions. Higher requirements during procurement should be put on the products, including demands on performed LCAs with clearly described references and methods, critically review by a third party.

The modern painting process in automotive industry is complex and a lot of factors affect the result. The trial and error method is used today to control the quality and introduce new colours. This method takes a lot of time and does not show any clear numbers of how the process is affected by changing the parameters. During this thesis, we have investigated a delimited number of parameters. The work is based on experiments performed on samples that represents a flat surface of the cab, to reduce experimental costs. Our master thesis is done at Scania in Oskarshamn, where all the cabs for the European production is produced. The objectives with this thesis has been to explain how the process parameters of the robotic applicator affect the paint distribution, paint thickness and the colour of the top coat. We also optimised the process by finding which settings gives an even paint distribution, a correct thickness and an accepted colour of the top coat. We have been using Design of Experiments to achieve the goals of this study. Design of Experiments is a statistic method that is used to perform experiments effectively. It also shows the effect of changing the factors from a low to a high level. We have chosen to divide the workflow into three parts: screening, optimisation and confirmation. The experiments are performed during the daily production to replicate the real circumstances. The shape air, paint flow and high rotation is the most important parameters to control. Paint flow also seems to have a linear impact on the thickness of the top coat layer. The Shape air and the high rotation on the other hand mainly affect the distribution of the top coat layer. Different levels are needed for the shape air and high rotation depending on what paint flow is used. The optimal settings of the factors for our colour were found to be paint flow at 82 %, the shape air at 90 %, the high rotation at 90 % and high voltage at 100 %. The optimal settings give a result of 1,535 μm in spread and 40,08 μm in mean thickness. Our settings compared to today’s results contributes to a reduced paint consumption, better quality and therefore less rework.