QoS framework for video streaming in home networks

In this thesis we present a new SNR scalable video coding scheme. An important advantage of the proposed scheme is that it requires just a standard video decoder for processing each layer. The quality of the delivered video depends on the allocation of bit rates to the base and enhancement layers. For a given total bit rate, the combination with a bigger base layer delivers higher quality. The absence of dependencies between frames in enhancement layers makes the system resilient to losses of arbitrary frames from an enhancement layer. Furthermore, that property can be used in a more controlled fashion. An important characteristic of any video streaming scheme is the ability to handle network bandwidth fluctuations. We made a streaming technique that observes the network conditions and based on the observations reconfigures the layer configuration in order to achieve the best possible quality. A change of the network conditions forces a change in the number of layers or the bit rate of these layers. Knowledge of the network conditions allows delivery of a video of higher quality by choosing an optimal layer configuration. When the network degrades, the amount of data transmitted per second is decreased by skipping frames from an enhancement layer on the sender side. The presented video coding scheme allows skipping any frame from an enhancement layer, thus enabling an efficient real-time control over transmission at the network level and fine-grained control over the decoding of video data. The methodology proposed is not MPEG-2 specific and can be applied to other coding standards. We made a terminal resource manager that enables trade-offs between quality and resource consumption due to the use of scalable video coding in combination with scalable video algorithms. The controller developed for the decoding process optimizes the perceived quality with respect to the CPU power available and the amount of input data. The controller does not depend on the type of scalability technique and can therefore be used with any scalable video. The controller uses the strategy that is created offline by means of a Markov Decision Process. During the evaluation it was found that the correctness of the controller behavior depends on the correctness of parameter settings for MDP, so user tests should be employed to find the optimal settings

EQUINE PITUITARY PARS INTERMEDIA DYSFUNCTION (PPID): PATHOPHYSIOLOGY AND A SURGICAL APPROACH TO TREATMENT

Equine pituitary pars intermedia dysfunction (PPID) is a common endocrine disease of the older horse. First described in 1932, and likened to human Cushing’s disease, it is associated with an enlargement of the pituitary gland that was classically termed an adenoma. The underlying mechanism is attributable to a lack of dopaminergic inhibition of the pars intermedia. Treatment methods have remained essentially unchanged for 30 years and the prevalence data have mainly stemmed from Eastern Australia and the USA. The general objective of this thesis was to explore the feasibility of developing a targeted cell-specific approach for the treatment of equine PPID. The specific aims were to confirm the need for this advanced therapy by determining the prevalence of PPID in horses globally; to continue the investigation of the underlying cellular mechanism of PPID by confirming the role of pro-hormone convertases, and sequence the equine pro-opiomelanocortin, prohormone convertase 1 and 2 genes; and to investigate the methodology for site-specific applications of future therapy for equine PPID. These aims were met by reporting the prevalence data from a worldwide audience of veterinarians using an internet-based survey tool; by describing partial gene sequences of the equine proopiomelanocortin and prohormone convertase enzymes and their expression in normal and PPID horses; and by showing how low-volume contrast enhancement of the brain using computed tomography can delineate the margins of the pituitary gland, showing how general anesthesia effects the pulsitility and concentration of adrenocorticotrophic hormone, and finally, modifying a previously reported technique, by developing a novel surgical approach to the treatment of this classical condition

Distributed Ledger Technology (DLT) Applications in Payment, Clearing, and Settlement Systems:A Study of Blockchain-Based Payment Barriers and Potential Solutions, and DLT Application in Central Bank Payment System Functions

Payment, clearing, and settlement systems are essential components of the financial markets and exert considerable influence on the overall economy. While there have been considerable technological advancements in payment systems, the conventional systems still depend on centralized architecture, with inherent limitations and risks. The emergence of Distributed ledger technology (DLT) is being regarded as a potential solution to transform payment and settlement processes and address certain challenges posed by the centralized architecture of traditional payment systems (Bank for International Settlements, 2017). While proof-of-concept projects have demonstrated the technical feasibility of DLT, significant barriers still hinder its adoption and implementation. The overarching objective of this thesis is to contribute to the developing area of DLT application in payment, clearing and settlement systems, which is still in its initial stages of applications development and lacks a substantial body of scholarly literature and empirical research. This is achieved by identifying the socio-technical barriers to adoption and diffusion of blockchain-based payment systems and the solutions proposed to address them. Furthermore, the thesis examines and classifies various applications of DLT in central bank payment system functions, offering valuable insights into the motivations, DLT platforms used, and consensus algorithms for applicable use cases. To achieve these objectives, the methodology employed involved a systematic literature review (SLR) of academic literature on blockchain-based payment systems. Furthermore, we utilized a thematic analysis approach to examine data collected from various sources regarding the use of DLT applications in central bank payment system functions, such as central bank white papers, industry reports, and policy documents. The study's findings on blockchain-based payment systems barriers and proposed solutions; challenge the prevailing emphasis on technological and regulatory barriers in the literature and industry discourse regarding the adoption and implementation of blockchain-based payment systems. It highlights the importance of considering the broader socio-technical context and identifying barriers across all five dimensions of the social technical framework, including technological, infrastructural, user practices/market, regulatory, and cultural dimensions. Furthermore, the research identified seven DLT applications in central bank payment system functions. These are grouped into three overarching themes: central banks' operational responsibilities in payment and settlement systems, issuance of central bank digital money, and regulatory oversight/supervisory functions, along with other ancillary functions. Each of these applications has unique motivations or value proposition, which is the underlying reason for utilizing in that particular use case

Developing an online support tool to assist students in higher education with project proposals

The research presented in this thesis investigates ways to assist students with writing their project proposals. There is limited literature on the problems students have when writing project proposals in Higher Education. Particularly most of the literature has concentrated on the writing aspects, rhetorical aspects and structure of a scientific article. Even though various studies on assessment of undergraduate individual and group project works have been done, the project proposal has not been given much attention. Therefore assessment of the proposal stage of the undergraduate final year project becomes the focus of this study, conducted over three years. This three-phase study directly involved three main stakeholders (students, supervisors and coordinators) in the overall process. In Phase 1, the existence of the proposal problems was investigated and identified from the perceptions of the students and supervisors. Possible solutions to the proposal problems were identified. Next Phase 2, I acknowledged the requirements of the stakeholders, which provided the framework and initiated the design and development of an eGuide, a self-paced online guide. The implementation and evaluation of the eGuide were then conducted in this phase. Finally Phase 3, the study emphasised improvement to practice focusing on the Degree final year project by utilizing the cyclic approach of an action research. Questionnaires and focus groups were used to gather information from students and supervisors, both to identify the problems they perceived with the student project proposal process and the effectiveness of the online support tool, eGuide. In the development of the eGuide, it proved necessary to design and pilot a robust rubric for students and supervisors to structure the project proposal process. The eGuide was evaluated for its effectiveness by the various users and followed by an action research approach to make further improvements to the Degree final year project curriculum. The assessment criteria evolved further to become a marking template with a very effective feedback tool. The study has a stimulating effect on the practices of how supervision of project proposal was shaped and how the project proposal was being assessed. Practical outcome of the study ultimately benefits not only the students who were the focus in the first place but also the supervisors and the coordinators. The study provides further avenues for research opportunities in this area to take place in the future

Spatial mode control and advanced methods for multi-platform quantum communication

Though state-of-the-art quantum computers are currently limited to only a handful of physical qubits, a quantum computer large enough to perform prime factorization of modern cryptographic keys, quantum simulation, and quantum-enhanced searching algorithms will likely become viable within a few decades. Such computers demand communication networks that preserve the qualities of the quantum states used as inputs and outputs; they also herald the end of the flavors of classical cryptography reliant on the complexity of factoring large numbers. As a result, future networks must include channels which preserve the states of single photons over useful distances (e.g., using quantum repeaters), and must deploy quantum-safe cryptography to ensure the safety of classical information passing over the network. Here we discuss strategies affecting several areas of a future quantum-enabled network: first, we demonstrate a technique for adaptively coupling single photons from point sources into single-mode optical fiber and apply the technique to coupling from quantum dots (a popular candidate for a future quantum repeater); secondly, we discuss various methods for simulating the effects of atmospheric turbulence on quantum cryptographic protocols in the laboratory, critical for understand the challenges facing free-space implementations of quantum communication. Thirdly, we demonstrate a technique that enables quantum cryptographic networks over free space channels to function in the presence of strong atmospheric turbulence using a multi-aperture receiver. Finally, we discuss our efforts to miniaturize a quantum key distribution system and operate a key distribution channel between flying multirotor drones

In Vitro Study of the Effects of Topical Treatments with Silver Compounds on the Inhibition of Demineralisation of Hydroxyapatite Discs and Human Enamel

PhD thesisIII Abstract Despite years of use, the enamel demineralisation inhibitory mechanisms of topical treatments with silver compounds remain obscure. This study aimed to investigate the effects of topical treatments with silver compounds, including AgNO3, AgF and Ag[NH3]2F (silver diammine fluoride; SDF), on demineralisation of hydroxyapatite (HAP) discs and human enamel. Further, the dose-response effects of these silver compounds on demineralisation of human enamel were also investigated. The dose-response effect of Ag+ in solution on demineralisation was investigated using scanning microradiography (SMR). The effects of topical treatments with AgNO3, AgF and Ag[NH3]2F on demineralisation of HAP discs and human enamel were investigated using real-time Ca2+, Ag+ and F- ion selective electrodes (ISEs), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and 31P and 19F magic angle spinning-nuclear magnetic resonance (MAS-NMR). The results from this study suggest that the inhibitory mechanism of topical treatment with AgNO3 is associated with the formation of a Ag3PO4 protective barrier. Whereas, the inhibitory mechanism of topical treatment with AgF or Ag[NH3]2F is associated with the F- released from topically treated sample surfaces and the formation of a protective barrier composed of Ag3PO4, CaF2 and FHA. Further, the inhibitory efficacy of topical treatment with AgNO3 decreased with increasing concentration, whereas, the inhibitory efficacy of topical treatment with AgF or Ag[NH3]2F increased with increasing concentration

Diet, nutrient status and gestational diabetes

Gestational diabetes mellitus (GDM) is one of the most common metabolic complications during pregnancy and prevalence has continued to increase worldwide. As BMI is one of the most important risk factors for development of GDM, prevention of GDM has focused on modifiable factors including diet. A range of dietary factors has been investigated, but results per dietary factor are limited and inconclusive (chapter 1). This thesis aims to provide more insight into dietary intake and nutrient status before and during pregnancy and into the association of dietary intake and nutrient status with risk of GDM. In addition, two methodological topics are addressed: the development of an index reflecting adherence to the Dutch dietary guidelines of 2015 and the effect of combining food frequency questionnaire (FFQ) and 24-hour recall (24hR) data on bias in diet-disease associations. In chapter 2, the development and evaluation of the Dutch Healthy Diet 2015 (DHD15) index score is described. The DHD15 index score assesses adherence to the Dutch dietary guidelines of 2015 and consists of 15 components representing the 15 food-based dietary guidelines. Per component the score ranges between zero and ten, resulting in a total score between zero (no adherence) and 150 (complete adherence). We evaluated the DHD15 index based on data from two 24hR and one FFQ from 885 men and women, aged 20-70 years, participating in the longitudinal NQplus study. A higher DHD15 index score was inversely associated with BMI, smoking, and intakes of energy, total fat, and saturated fat and positively associated with energy-adjusted micronutrient intakes. We concluded that the DHD15 index is a good marker of diet quality. Measurement error in dietary intakes leads to biased diet-disease associations. If dietary intake is assessed with a second method, regression calibration (RC) or enhanced regression calibration (ERC) can be used to combine dietary intakes. This could result in less biased associations. In chapter 3, we investigated the effect of combining dietary intakes obtained with two methods (24hR and FFQ) on diet-disease associations using data from 236 participants of the NQplus study. We observed that combining FFQ and 24hR data with RC and ERC for protein and potassium resulted in empirical attenuation factors approaching 1, indicating less biased diet-disease associations. In chapter 4, the prevalence of common delivery-related adverse pregnancy outcomes was compared between women with normal glucose tolerance during pregnancy (NGT), women with treated GDM and women with untreated borderline GDM (BGDM). BGDM was defined as women with an abnormal 50-grams glucose challenge test and a normal 75-grams oral glucose tolerance test. Medical file data were used from 1049 women who had undergone GDM screening and had given birth in hospital Gelderse Vallei Ede in the period 2010-2014. Women with treated GDM had a higher risk of laceration and women with untreated BGDM had a higher risk of laceration and (unscheduled) Caesarean section as compared to women with NGT. Furthermore, we observed that associations between glucose tolerance and adverse pregnancy outcomes were not mediated by macrosomia (birth weight >4000 gram). In chapter 5, the associations between pre-pregnancy dietary carbohydrate quantity and quality with risk of GDM were investigated in women of reproductive age in an Australian cohort. A total of 3,607 women aged 25-30 years were followed-up for self-reported GDM development from 2003 till 2015. Pre-pregnancy dietary intake was assessed with a FFQ in 2003 and 2009. Carbohydrate quantity was assessed based on total carbohydrate intake and the low-carbohydrate diet (LCD) score. Carbohydrate quality was assessed by studying fibre intake, total sugar intake, glycaemic index, glycaemic load and intake of carbohydrate-rich food groups. A relatively low carbohydrate and high fat and protein intake as expressed by the LCD score and a higher cereal intake were significantly associated with higher risk of GDM, whereas higher fibre, fruit and fruit juice intakes were associated with lower risk of GDM. Chapter 6 describes the prevalence of inadequate micronutrient intakes and the association of pre-pregnancy micronutrient adequacy with risk of GDM in the same Australian cohort of women of reproductive age. We used a summary measure of adequate micronutrient intake across 13 micronutrients, i.e. the mean adequacy ratio (MAR). Prevalence of inadequate dietary micronutrient intake was more than 50% for the micronutrients calcium, potassium, magnesium, vitamin E and folate, indicating suboptimal pre-pregnancy micronutrient intakes. A higher overall micronutrient adequacy (i.e. MAR) was associated with a lower risk of developing GDM. In chapter 7, changes in folate, vitamin B6, vitamin B12, vitamin D and iron intake, their status markers and diet quality from preconception to the second trimester of pregnancy are described. In addition, associations of these micronutrient intakes, their status markers and diet quality with glucose tolerance during pregnancy were examined. Data from 91 Dutch women at increased risk of GDM, aged 18-40 years, and with either a wish to get pregnant or less than 24 weeks pregnant was collected longitudinally. Data was collected at preconception (n=67), 12 weeks of pregnancy (n=47) and 24 weeks of pregnancy (n=55). At each time point women underwent a fasting venipuncture and a 75-grams oral glucose tolerance test. Dietary intake was assessed at each time point with a validated FFQ and two non-consecutive 24hR. We observed significant changes in total micronutrient intakes throughout pregnancy, due to changes in supplemental intakes, whereas dietary micronutrient intakes and diet quality remained stable. Nutrient status levels changed significantly from preconception to the second trimester of pregnancy. For folate, vitamin B6 and vitamin D this could be partly explained by changes in intake. In general, no associations between fasting and 2-hour glucose levels and HbA1c levels with diet quality, micronutrient intake or status levels were observed; except for a weak inverse association of folate intake with 2-hour glucose levels, and a weak positive association between ferritin and 2-hour glucose levels. Diet quality was inversely associated with fasting glucose in a sensitivity analysis, excluding data from participants with only one measurement. Using data from the same study collected at preconception from the same study (n=66), main dietary sources of folate, vitamin D, and the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were determined in chapter 8. Additionally, associations of these intakes with their blood levels were examined. A large proportion of women did not meet the Dutch recommended intakes of folate (50%), vitamin D (67%), and EPA+DHA (52%). Vegetables were the main contributor of dietary folate intake (25%), oils and fats of dietary vitamin D intake (39%), and fish of dietary EPA and DHA intake (69%). Fourteen percent had an inadequate folate status and 23% an inadequate vitamin D status. Supplemental folate intake, supplemental and dietary vitamin D intake and dietary EPA+DHA intake were significantly associated with their blood levels. In chapter 9, the main findings of this thesis were summarized and a reflection on methodological aspects was given. Considering results described in this thesis and associations reported by other studies, it is probable that a healthy diet can reduce risk of developing GDM. Most convincing evidence was observed for diet in the pre-pregnancy period. More research is needed to understand which foods and nutrients drive diet-GDM associations, and to unravel underlying mechanisms. Diet in the pre-pregnancy period was considered suboptimal and intakes of several vital micronutrients, including folate, were below recommended intakes for a large proportion of women in two different studies. Although the Health Council of the Netherlands already called upon the provision of proper and adequate preconception care a decade ago, more action is needed to improve intake and status of essential micronutrients in the preconception period.</p

Prospects for Electric Mobility: Systemic, Economic and Environmental Issues

The transport sector, which is currently almost completely based on fossil fuels, is one of the major contributors to greenhouse gas emissions. Heading towards a more sustainable development of mobility could be possible with more energy efficient automotive technologies such as battery electric vehicles. The number of electric vehicles has been increasing over the last decade, but there are still many challenges that have to be solved in the future. This Special Issue “Prospects for Electric Mobility: Systemic, Economic and Environmental Issues” contributes to the better understanding of the current situation as well as the future prospects and impediments for electro mobility. The published papers range from historical development of electricity use in different transport modes and the recent challenges up to future perspectives