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Adaptive threshold and optimal frame duration for multi-taper spectrum sensing in cognitive radio
No full textThis paper delivers an accurate approximation for adaptive threshold and optimal frame detection algorithms based on the robust multitaper method aiming at an efficient spectrum sensing in cognitive radio systems. An appropriate adaptive thresholding allows for seamless vacation of unlicensed secondary users from certain bands upon primary users’ requests, while arbitrary optimal frame detection contributes to the computational and throughput demands. Simulation exercises corroborate the given analysis over Rayleigh channel and multiple-input multiple-output configuration and emphasize the critical role of adopting applicable adaptive threshold and optimal frame detection policies
Pregnancy-specific health anxiety: symptom or diagnosis?
No full textAnxiety is an innate human response to situations that cause fear, worry or concern. One such type is health anxiety. Health anxiety is a term derived from hypochondriasis and divided into two disorders: illness anxiety disorder and somatic symptom disorder. Symptoms can range from mild-to-moderate expressions of worry to clinical diagnoses. Previous research has shown pregnancy-specific anxiety to be an autonomous anxiety disorder. When a woman conceives, immediate somatic changes are experienced, and although all pregnancies are different, these changes could cause either illness anxiety disorder or somatic symptom disorder. This review explores the possibility of pregnancy-specific health anxiety in greater detail
Education and the ‘new’ neoliberalism
No full textThis Chapter examines the origins of neoliberalism as liberal economic approach with a social conscience to solving the economic problems of the 1930's by the German Ordoliberalists, the Mont Pelarin Group and the Chicago School of economists. This is compared to the re-emergence of neoliberalism in the 1980's as a broad critical commentary on the effect of political economies returning to a liberal economic approach in which a distinct global political economy of education has developed. By comparing different political approaches to this 'new' neoliberalism the chapter provides a conceptual base for students of education to debate the nature and purpose of current neoliberal approaches to education
Becoming sociological: a brief historical review of leisure in the social survey 1880–1939
No full textAdopting the social survey as an analytical tool, this paper explores the origins of a sociology of leisure. Modern social understandings of leisure were formed in the expansion of the social sciences in the late nineteenth century in parallel with the growth of systematic and scientifically informed social work. In both Great Britain and the United States of America the survey became a widely adopted method of gathering data to inform social work. Through advances in social work and the settlement movement’s association with universities an embryonic sociology of leisure had emerged by 1914. After the First World War leisure became a field of policy discourse in post-war reconstruction and the subject of large scale surveys in both countries. These surveys give insight to new and changing sociological understandings of leisure which provided the foundations for the formal recognition of leisure as a sociological field in the late twentieth century
An appraisal of the 2008 University of Bolton summer schools
No full textThis report provides an appraisal of the 2008 University summer schools to determine their efficacy as an instrument to meet students? developmental needs. Their introduction is not a new approach but one that has been encouraged to be developed to further increase retention rates
A portable triboelectric nanogenerator for real-time respiration monitoring.
No full textAs a reliable indicator of human physiological health, respiratory rate has been utilized in more and more cases for prediction and diagnosis of potential respiratory diseases and the respiratory dysfunction caused by cystic fibrosis. However, compared with smart mobile electronics, traditional clinical respiration monitoring systems is not convenient to work as a household wearable device for real-time respiration monitoring in daily life due to its cumbersome structure, complex operability, and reliance on external power sources. Thus, we propose a wearable wireless respiration sensor based on lateral sliding mode triboelectric nanogenerator (TENG) to monitor respiratory rates by sensing the variation of the abdominal circumference. In this paper, we validate the possibility of the device as a respiration monitoring sensor via an established theoretical model and investigate the output performance of the sensor via a series of mechanical tests. Furtherly, the applications of the respiration sensor in different individuals, different breathing rhythms, different active states, and wireless transmission have been verified by a lot of volunteer tests. All the results demonstrate the potential of the proposed wearable sensor as a new alternative for detecting and monitoring real-time respiratory rates with general applicability and sensitivity
OFDM systems design using harmonic wavelets
No full textOrthogonal frequency-division multiplexing (OFDM) is a popular multi-carrier technique used in many digital communication systems such as wireless fidelity (Wi-Fi), long term evolution (LTE) and power line communication systems. It can be designed using fast Fourier transform (FFT) or wavelet transform (WT). The major drawback in using WT is that it is computationally inefficient. In this study, we introduce a simple and computationally efficient WT, harmonic wavelet transform, for OFDM signal processing. The new WT uses the orthogonal basis functions of conventional FFT-OFDM except that it involves translation and dilation of the input signal; the new wavelets is referred to as harmonic wavelets (HW). When compared with pilot-assisted OFDM system in terms of reduction in the peak-to-average power ratio, the results show that HW-OFDM outperforms FFT-OFDM by 3 dB at 10−4 CCDF (complementary cumulative distribution function). Over Rayleigh fading channel with additive white Gaussian noise (AWGN), the bit error ratio of both FFT-OFDM and HW-OFDM perfectly matched, showing that the proposed HW-OFDM is better in terms of peak-to-average power ratio reduction
A positive virtual ecosystem. The theory of change for Kooth. Comprehensive Report
No full textKooth is an online mental health service for children and young people*. Since its launch in 2004, it has grown with the children and young people who use it, its humanistic approach shaped by their demand and our clinical expertise.Today it is a large, thriving and diverse community of young people who use it for multifarious reasons and in multifarious ways; importantly, they have the power to direct support themselves. They and are in control of their therapeutic journey. The service is full of choices in terms of how to get help, but also in terms of the therapeutic support available. As such, it is an extremely complex entity, perhaps reflecting the very nature of wellbeing and mental health.As well as making this an extremely rich environment where young people actively choose to spend their time, it has also taken the service well beyond what today’s quantitative outcomes measures of mental health services can capture.This paper signals the beginning of an important, ground-breaking journey to define the role and the impact of Kooth. We have explored, mapped and categorised activity within the service with a specific goal in mind: to define our Theory of Change. This describes the Kooth experience and the many routes in and out of the service, each reliant on our understanding of an individual’s unique building blocks for wellness.The Theory of Change (ToC) is not a clinical model and nor does it seek to be. It is not there to show how we can address specific standalone symptoms. Instead it is a characterisation of the broad, person-centred, holistic work Kooth does every day.It is also the foundation for a future set of mental health outcome measures, which will represent each child or young person’s journey
Nanomaterials enabled advanced renewable energy technologies
No full textThe impending environmental crisis necessitates a pressing need to develop the next generation energy harvesting and generating technologies, ranging from the µW to W range.To this effect, this thesis focuses on the development of materials, measurement and analysis of devices for alternate energy devices ranging from energy harvesting nanogenerators (µW-mW range) to fuel cells (mW-W range). The work has been carried out in two parts, wherein part A encompasses seedless deposition of zinc oxide (ZnO) nanosheets via a facile electrochemical deposition method and study of its inherent piezoelectric and structural properties to fabricate piezoelectric and triboelectric effect based nanogenerators. In part B, an in-depth comparative study of platinum catalyst loaded on various two-dimensional (graphene nanoplatelets, graphene oxide) and one-dimensional (multi-walled carbon nanotubes) carbon nanostructures was carried out for enabling relatively inexpensive and stable materials for cathodic oxygen reduction reaction (ORR) in fuel cell applications.The ZnO nanosheet structures were synthesised on various conductive substrates using a low temperature electrochemical deposition process. The seedless deposition of ZnO nanosheets on Al substrates exhibited a honeycomb network like morphology with an additional plane of ZnO_Al.LDH with the layered double hydroxide (LDH) layer being highly conducive for the fabrication of piezoelectric nanogenerator (PENG) devices. The typical PENG devices developed using a metal/piezoelectric/metal structure with a ITO/ZnO_Al:LDH/Al configuration exhibited a maximum open circuit voltage (Voc) of ~0.7 V and a current density (JSC) of ~0.50 mAm-2 under an applied force of 80 N. To enhance the output power utilising the inherent piezoelectric properties of ZnO nanosheets, the ZnO:Al substrates were used as a charge injection interfacial layer in a triboelectric nanogenerator (TENG). A typical TENG comprising of a triboelectric negative composite of zinc stannate (ZnSnO3)/polyvinylidene fluoride (PVDF) blended with an interfacial ZnO nanosheet layer and a polyamide-6 (PA6) membrane as the triboelectric positive exhibited significantly higher power output than the PENG devices. The phase-inversion process for the synthesis of triboelectric membranes enabled a high piezoelectric coefficient for not only the pristine PVDF fluoropolymer membranes (d33 ~ -44 pmV-1) but also for the composite ZnSnO3/PVDF/ZnO:Al membranes (d33 ~ -74 pmV-1) as confirmed by piezo force microscopy (PFM) analysis. At a comparative 80 N force, the ZnSnO3/PVDF/ZnO:Al vs PA-6 TENG produced significantly higher Voc and Jsc of ~625 V and ~40 mAm-2 with a corresponding charge density of 100.6 μCm-2, respectively. The PFM analysis confirmed the interfacial dipole-dipole interactions occurring with the ferroelectric polarization of ZnSnO3-PVDF, promoting the alignment of polar axis of ZnO. Under the compressive stress during the TENG measurements, the piezoelectric potential produced in the ZnO nanosheets provides charge injection onto the surface of ZnSnO3-PVDF membrane, enhancing the charge density, which in-turn significantly enhances the power density from 0.11 to ~1.8 W/m2. Although the energy produced using this process is dynamic in nature, i.e. depends on the contact release cycles, the operation and the fabrication of energy harvesting devices is very economical and simple, thus making both the PENG and TENG devices excellent candidates for realising energy harvesting and self-powered electronic systems.In the area of fuel cells, the literature points to a significant on-going debate over the role of carbon supports in catalysing the ORR. The electrochemical performance of pristine carbon supports, including graphene nanoplatelets (GNP), graphene oxide (GO) and multi walled carbon nanotubes (MWCNTs) for catalysing ORR in an alkaline media (0.1M KOH), were studied and compared in detail. Amongst these supports, the pristine MWCNTs displayed a promising peak reduction current densities of ~3 mA/cm2, followed by GNP ~1.5 mA/cm2 and GO ~1.0 mA/cm2. The peak reduction potentials obtained by MWCNTs is comparable to heteroatom N- and B-doped MWCNTs. Further a variable metallic Pt (Pt0) loading values ranging from 20% to 50% was achived by using microwave-assisted polyol process on pristine carbon supports. A Pt loading-normalised comparison of ORR current densities shows that Pt/MWCNTs exhibited the highest linear sweep voltammetry (LSV) reduction current density of ~ 900 A/g, much higher than ~ 510 A/g of the commercial Pt carbon black supports, followed by Pt/GNP and Pt/GO that have the LSV value of ~500 A/g and ~200 A/g LSV, respectively. It is therefore suggested that the Pt/MWCNTs should be given a favourable consideration in ORR for the future development of fuel cell technologie
OFDM Systems Design Using Harmonic Wavelets
No full textOrthogonal frequency-division multiplexing (OFDM) is a popular multi-carrier technique used in many digital communication systems such as wireless fidelity (Wi-Fi), long term evolution (LTE) and power line communication systems. It can be designed using fast Fourier transform (FFT) or wavelet transform (WT). The major drawback in using WT is that it is computationally inefficient. In this study, we introduce a simple and computationally efficient WT, harmonic wavelet transform, for OFDM signal processing. The new WT uses the orthogonal basis functions of conventional FFT-OFDM except that it involves translation and dilation of the input signal; the new wavelets is referred to as harmonic wavelets (HW). When compared with pilot-assisted OFDM system in terms of reduction in the peak-to-average power ratio, the results show that HW-OFDM outperforms FFT-OFDM by 3 dB at 10(-4) CCDF (complementary cumulative distribution function). Over Rayleigh fading channel with additive white Gaussian noise (AWGN), the bit error ratio of both FFT-OFDM and HW-OFDM perfectly matched, showing that the proposed HW-OFDM is better in terms of peak-to-average power ratio reduction