I ett kortbetalningssystem såsom Visa International Service Association (Visa) finns det fem stycken tongivande parter: kortinlösaren; kortutgivaren; kortinnehavaren; säljföretaget och Payment Service Provider (PSP). Ett säljföretag som låter sina kunder betala för varor och tjänster på sin webbplats skickar kundernas kortnummer krypterat till en PSP som vidarebefodrar dessa till VisaNet som är dataknutpunkten i Visa. VisaNet söker med hjälp utav kortnumret upp den bank som har utgivit kortet och efterfrågar samma bank om en transaktion får ske från kortet. VisaNet får ett svar som vidarebefordras vidare tillbaka till säljföretaget som sedermera även får sina pengar överförda till sitt konto från kundens konto. Uppdragsgivaren till detta examensarbete skall utveckla ett helt eget system och bli sin egen PSP utifall uppdragsgivaren beräknar att mer än 1,3 miljoner stycken kortbetalningar kommer att ske genom uppdragsgivarens kortbetalningssystem per år. När detta examensarbete utfördes uppskattades antalet kortbetalningar per år inte till denna siffra och rapportförfattaren utvecklade därför ett korbetalningssystem med hjälp utav en befintlig PSP. Kortbetalningssystemets kärna är ett API som andra systemutvecklare hos uppdragsgivaren kan anropa. API:t har ett antal funktioner såsom att utföra en kortbetalning, reservera en kortbetalning eller att avbryta en reserverad kortbetalning. Rapportförfattaren har även utvecklat ett grafiskt övervaknings- och administrationsgränssnitt för att kunna övervaka de kortbetalningar som sker samt enkelt kunna felsöka fel som uppstår i systemet.

This thesis investigates the use of Maximum Likelihood Sequence Estimation (MLSE) in the presence of unknown channel parameters. MLSE is a fundamental problem that is closely related to many modern research areas like Space-Time Coding, Overloaded Array Processing and Multi-User Detection. Per-Survivor Processing (PSP) is a technique for approximating MLSE for unknown channels by embedding channel estimation into the structure of the Viterbi Algorithm (VA). In the case of successful acquisition, the convergence rate of PSP is comparable to that of the pilot-aided RLS algorithm. However, the performance of PSP degrades when certain sequences are transmitted. In this thesis, the blind acquisition characteristics of PSP are discussed. The problematic sequences for any joint ML data and channel estimator are discussed from an analytic perspective. Based on the theory of indistinguishable sequences, modifications to conventional PSP are suggested that improve its acquisition performance significantly. The effect of tree search and list-based algorithms on PSP is also discussed. Proposed improvement techniques are compared for different channels. For higher order channels, complexity issues dominate the choice of algorithms, so PSP with state reduction techniques is considered. Typical misacquisition conditions, transients, and initialization issues are reported. / Master of Science

The subject of this thesis is a qualitative analysis of the usability of three contemporary programming languages: Perl, Python, and Tcl. The relative usability of these languages was assessed by implementing two representative applications — a paint program and a chat program — in all three languages; using PSP to collect data on program development; and then comparing development times, defect counts, and defect fix times. Overall, Python was the easiest of the three languages to use, especially for new users. Perl is the hardest, and Tcl is somewhere between. Specifically, Perl's basic language constructs are the hardest to learn and to use. Python's are the easiest. Tcl's are closer to Python's. Python's and Tcl's mechanisms for supporting OO are much easier to learn for new users than Perl's. Python's Tk libraries are easier to use than Perl's and Tcl's. Tcl's [Incr Widget] (megawidgets) library is by far the hardest to master. Perl's Tk library is somewhere in between. Perl's I/O and Socket libraries are much harder to use than Python's and Tcl's. The primary recommendations of this study are as follows: For Perl, a better OO support will reduce a significant number of OO-related defects, especially to new users. For Tcl, Tcl's [Incr Tcl] megawidget library should wrap the standard raw Tk widgets into [Incr Tk] classes, to prevent a significant number of defects from mixture uses of raw Tk widgets and [incr Tk] megawidgets classes. Tcl's eventloop mechanism is a good model for handling non-blocking sockets and I/Os. Both Perl and Python should also provide such an easy model.

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No description available.

The majority of Swedish boys and girls have good psychosomatic health. Despite that the risk of mental health problems such as nervousness, feeling low and sleeping difficulties has increased steadily in recent decades. Moreover, previous surveys on health and well-being indicate that boys and girls of foreign extraction in Sweden are at increased risk of ill health compared to boys and girls of Swedish background.   The main aim of this thesis was to analyse health and social determinants among boys and girls of foreign extraction in Sweden. The factors explored in papers I–IV include parental background, family affluence and gender and their associations with subjective health complaints, psychosomatic problems or health risk behaviours. Other included risk factors for ill health were involvement in bullying, low participation and discrimination at school. This thesis takes an intersectional perspective, with ambitions to be able to emphasize the interplay between different power relations (i.e. gender, social class and parental background).   Two sets of cross-sectional data were used. Three papers were based on the Swedish part of the World Health Organization’s Health Behaviour in School-Aged Children. The sample consisted of 11,972 children (boys n = 6054; girls n = 5918) in grades five, seven and nine from the measurement years 1997/98, 2001/02 and 2005/06. The response rate varied between 85 and 90%. About one fifth of the included children were of foreign extraction. For the fourth paper regional data from Northern Sweden were used. Boys (n = 729) and girls (n = 798) in grades six to nine answered a questionnaire in 2011 and the response rate was 80%. About 14% of the included children were of foreign extraction. Statistical methods used were chi-square test, correlation analyses, logistic regression analyses, cluster analyses and test of mediating factor.   The results showed that girls of foreign background were at increased risk of subjective health complaints (SHC) and boys of mixed background were at increased risk of psychosomatic problems (PSP). Increased risk of allocation to the cluster profile of multiple risk behaviour was shown in boys and girls of mixed background, in girls of foreign background and in girls of low family affluence. Increased risk of allocation to the cluster profile of inadequate tooth brushing was shown in boys and girls of foreign background and in girls of low family affluence. General risk factors for increased risk of ill health for boys and girls in Sweden were: any form of bullying involvement, low family affluence, low participation and discrimination at school, of which the latter also was a mediating factor for ill health. Living with a single parent was a risk factor for ill health among girls.   The results can function as a basis for developing health promotion programmes at schools that focus on social consequences of foreign extraction, family affluence, participation as well as health risk behaviours and gender. / Majoriteten av flickorna och pojkarna i Sverige har en god psykosomatisk hälsa. Trots det har risken för psykiska hälsosymptom såsom nervositet, att känna sig nere och sömnsvårigheter ökat successivt de senaste årtiondena. Dessutom indikerar tidigare forskning angående hälsa och välmående att flickor och pojkar med utländsk härkomst har ökad risk för ohälsa jämfört med flickor och pojkar med svensk härkomst.   Denna avhandlings huvudsyfte var att analysera hälsa och sociala bestämningsfaktorer bland flickor och pojkar i Sverige, med fokus på föräldrabakgrund. Artiklarnas (I–IV) syften inkluderar föräldrahärkomst, familjens materiella tillgångar och genus samt dess samband med subjektiva hälsobesvär, psykosomatiska problem eller hälsoriskbeteenden. Andra riskfaktorer för ohälsa som inkluderades var inblandning i mobbning, lågt deltagande och förekomst av diskriminering på skolan. Denna avhandling beaktar ett intersektionellt perspektiv med ambitionen att kunna tydliggöra samspelet mellan olika maktordningar (dvs. genus, social klass och föräldrabakgrund).   Två dataset från tvärsnittsstudier har använts. I de tre första artiklarna användes World Health Organization – Health Behaviour in School-Aged Children, som i Sverige heter Svenska skolbarns hälsovanor. Studiepopulationen bestod av 11 972 barn (flickor n = 5918; pojkar n = 6054) i årskurserna fem, sju och nio undersöknings år 1997/98, 2001/02 och 2005/06. Svarsfrekvensen var mellan 85 och 90 %. Ungefär en femtedel av barnen som deltog hade utländsk härkomst. I den fjärde artikeln användes regional data från norra Sverige. Flickor (n = 798) och pojkar (n = 729) i årskurserna sex till nio deltog i studien år 2011, svarsfrekvensen var 80 %. Omkring 14 % av barnen hade utländsk härkomst. De statistiska metoder som användes var sambandstest (chi-två), test av linjära samband så kallade korrelationsanalyser, logistisk regressionsanalys, klusteranalys och test av medierande faktor.   Resultaten visade att flickor med utländsk bakgrund hade ökad risk för subjektiva hälsobesvär (SHC) och pojkar av mixbakgrund hade ökad risk för psykosomatiska problem (PSP). Ökad risk för att hamna i klusterprofilen multipelt hälsoriskbeteende hade flickor och pojkar med mixbakgrund, flickor med utländsk bakgrund samt flickor i familjer med låg nivå av materiella tillgångar. Ökad risk för att hamna i klusterprofilen bristande tandborstning hade flickor och pojkar med utländsk bakgrund och flickor i familjer med låg nivå av materiella tillgångar. Generella riskfaktorer för ohälsa bland flickor och pojkar i Sverige var: alla former av inblandning i mobbning, låg nivå av materiella tillgångar i familjen, lågt deltagande och förekomst av diskriminering på skolan, vilken den senare även var en medierande faktor för ohälsa. Att leva med en ensamstående förälder var en riskfaktor för ohälsa bland flickor.   Avhandlingens resultat kan ligga till grund för utformande av hälsofrämjande interventioner inom elevhälsan, till exempel interventioner som fokuserar på sociala konsekvenser av utländsk härkomst, familjens materiella tillgångar, deltagande och diskriminering samt hälsoriskbeteenden och genus.

Maintaining cell envelope integrity is of vital importance for all microorganisms. Not surprisingly, evolution has shaped conserved protein protection networks that connect stress perception, transmembrane signal transduction, and mediation of cellular responses upon cell envelope stress. The phage shock protein (Psp) stress response is one such conserved protection network. Most knowledge about the Psp response derives from studies in the Gram-negative model bacterium Escherichia coli, where the Psp system consists of several well-defined protein components. Homologous systems were identified in representatives of the Proteobacteria, Actinobacteria, and Firmicutes. However, the Psp system distribution in the microbial world remains largely unknown. By carrying out a large-scale, unbiased comparative genomics analysis, we found components of the Psp system in many bacterial and archaeal phyla and describe that the predicted Psp systems deviate dramatically from the known prototypes. The core proteins PspA and PspC have been integrated into various (often phylum-specifically) conserved protein networks during evolution. Based on protein domain-based and gene neighborhood analyses of pspA and pspC homologs, we built a natural classification system for Psp networks in bacteria and archaea. We validate our approach by performing a comprehensive in vivo protein interaction study of Psp domains identified in the Gram-positive model organism Bacillus subtilis and found a strong interconnected protein network. Our study highlights the diversity of Psp domain organizations and potentially diverse functions across the plethora of the microbial landscape, thus laying the ground for studies beyond known Psp functions in underrepresented organisms.

Arc Flash events occur due to faults in electrical equipment combined with a significant release of energy across an electrical arc. Due to the large energy release, plasma is generated, pressures increase, and the plasma expands. Under these conditions the plasma becomes excited enough to liquefy metal causing physical damage to equipment and any humans in the vicinity. This thesis investigates the state of art for detection of arc flash events and investigates a method of improving detection reliability, and speed by monitoring the high frequency voltage / current patterns utilizing methods similar to arc flash circuit interrupters (AFCI). A second alternative detection approach is determined through analysis of the physics of plasma development. The current state of art is based upon light detection. However this thesis experimentally investigates what happens before the arc event emits visible light. The results show that current flows to ground during an arc event slightly prior to the production of light. Further it shows through analysis of the physics of plasma that a high speed plasma detector has the potential to identify an arc event before the presence of visible light. Through the design and construction of experimental test setups, and physics analysis, this thesis provides new paths for detecting arc events that present opportunities to improve detection time.

La notion de qualité de service (QoS) est un concept important pour transporter sur les réseaux de l'information avec un maximum de fiabilité. Les métriques de la QoS sont le débit, le délai, la gigue et le taux de pertes. Par ailleurs, la multiplicité des applications conduit à une hétérogénéité des données : les flots élastiques requièrent un débit soutenu et les flots non élastiques exigeants en délai. Les algorithmes d'ordonnancement à différenciation proportionnelle permettent de partager équitablement les ressources entre les applications, selon leurs besoins. Toutefois, la proportionnalité ne s'est jusque-là effectuée que selon un seul critère de qualité (débit, délai ou taux de perte). Nous proposons un algorithme d'ordonnancement à différenciation proportionnelle, fondée sur la fonction de puissance mettant en rapport deux critères : le délai et le débit. L'ordonnanceur PSP (Power as a Scheduling Parameter) offre un partage équitable des ressources entre les applications à besoins différents de manière à ce qu'aucune classe ne subisse de phénomène de famine. L'implémentation et les tests de l'ordonnanceur ont été réalisés au moyen de l'outil de simulation ns-2.

The dementias are persistent or progressive disorders affecting more than one cognitive domain that interfere with an individual’s ability to function at work or home, and represent a decline from a previous level of function. In this thesis I consider the neurophysiology of dementia at a number of levels. I investigate the ways in which the connectivity and function of the brain predisposes to the specific focal patterns of neurodegeneration seen in the various dementias. I aim to identify the mesoscopic changes that occur in individuals with neurodegeneration and how these relate to their cognitive difficulties. I show how, by assessing patients in whom there is focal disruption of brain networks and observing the outcomes in comparison to controls, I can gain insight into the mechanisms by which the normal brain makes predictions and processes language. In Chapter 1, I set the scene for the focussed experimental investigations of model diseases by beginning with an introductory, clinically-focussed review that sets out the features, aetiology, management, epidemiology and prognosis of the dementias. This places these model diseases in the context of the broader clinical challenge posed by the dementias. In Chapter 2, I turn to ‘prototypical’ model diseases that represent neurodegenerative tauopathies with predominantly cortical (Alzheimer’s disease, AD) and subcortical (Progressive Supranuclear Palsy, PSP) disease burdens. I investigate the neurophysiological causes and consequences of Tau accumulation by combining graph theoretical analyses of resting state functional MR imaging and in vivo ‘Tau’ PET imaging using the ligand AV-1451. By relating Tau distribution to the functional connectome I provide in vivo evidence consistent with ‘prion-like’ trans-neuronal spread of Tau in AD but not PSP. This provides important validation of disease modification strategies that aim to halt or slow down the progression of AD by sequestration of pathological Tau in the synapse. In contrast, I demonstrate associations consistent with regional vulnerability to Tau accumulation due to metabolic demand and a lack of trophic support in PSP but not AD. With a cross-sectional approach, using Tau burden as a surrogate marker of disease severity, I then go on to show how the changes in functional connectivity that occur as disease progresses account for the contrasting cognitive phenotypes in AD and PSP. In advancing AD, functional connectivity across the whole brain becomes increasingly random and disorganised, accounting for symptomatology across multiple cognitive domains. In advancing PSP, by contrast, disrupted cortico-subcortical and cortico-brainstem interactions meant that information transfer passed through a larger number of cortical nodes, reducing closeness centrality and eigenvector centrality, while increasing weighted degree, clustering, betweenness centrality and local efficiency. Together, this resulted in increasingly modular processing with inter-network communication taking less direct paths, accounting for the bradyphrenia characteristic of the ‘subcortical dementias’. From chapter 3 onwards, I turn to the in-depth study of a model disease called non-fluent variant Primary Progressive Aphasia (nfvPPA). This disease has a clear clinical phenotype of speech apraxia and agrammatism, associated with a focal pattern of mild atrophy in frontal lobes. Importantly, general cognition is usually well preserved until late disease. In chapter 3 itself, I relate an experiment in which patients with nfvPPA and matched controls performed a receptive language task while having their brain activity recorded with magnetoencephalography. I manipulated expectations and sensory detail to explore the role of top-down frontal contributions to predictive processes in speech perception. I demonstrate that frontal neurodegeneration led to inflexible and excessively precise predictions, and that fronto-temporal interactions play a causal role in reconciling prior predictions with degraded sensory signals. The discussion here concentrates on the insights provided by neurodegenerative disease into the normal function of the brain in processing language. Overall, I demonstrate that higher level frontal mechanisms for cognitive and behavioural flexibility make a critical functional contribution to the hierarchical generative models underlying speech perception In chapter 4, I precisely define the sequence processing and statistical learning abilities of patients with nfvPPA in comparison to patients with non-fluent aphasia due to stroke and neurological controls. I do this by exposing participants to a novel, mixed-complexity artificial grammar designed to assess processing of increasingly complex sequencing relationships, and then assessing the degree of implicit rule learning. I demonstrate that agrammatic aphasics of two different aetiologies are not disproportionately impaired on complex sequencing relationships, and that the learning of phonological and non-linguistic sequences occurs independently in health and disease. In chapter 5, I summarise the synergies between the experimental chapters, and explain how I have applied a systems identification framework to a diverse set of experimental methods, with the common goal of defining the physiology of dementia. I then return to the results of chapter 3 with a clinical focus to explain how inflexible predictions can account for subjective speech comprehension difficulties, auditory processing abnormalities and (in synthesis with chapter 4) receptive agrammatism in nfvPPA. Overall, this body of work has contributed to knowledge in several ways. It has achieved its tripartite aims by: 1) Providing in vivo evidence consistent with theoretical models of trans-neuronal Tau spread (chapter 2), and a comprehensive clinical account of the previously poorly-understood receptive symptomatology of nfvPPA (chapter 5), thus demonstrating that systems neuroscience can provide a translational bridge between the molecular biology of dementia and clinical trials of therapies and medications. In this way, I begin to disentangle the network-level causes of neurodegeneration from its consequences. 2) Providing evidence for a causal role for fronto-temporal interactions in language processing (chapter 3), and demonstrating domain separation of statistical learning between linguistic and non-linguistic sequences (chapter 4), thus demonstrating that studies of patients with neurodegenerative disease can further our understanding of normative brain function. 3) Successfully integrating neuropsychology, behavioural psychophysics, functional MRI, structural MRI, magnetoencephalography and computational modelling to provide comprehensive research training, as the platform for a future research programme in the physiology of dementia.