100 research outputs found

    A Wideband Reconfigurable Intelligent Surface for 5G Millimeter-Wave Applications

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    Despite the growing interest in reconfigurable intelligent surfaces (RISs) for millimeter-wave (mm-wave) bands, and the considerable theoretical work reported by the communication community, there is a limited number of published works demonstrating practical implementations and experimental results. To the authors' knowledge, no published literature has reported experimental results for RISs covering the n257 and n258 mm-wave bands. In this work, we propose a novel wideband RIS design that covers the entire mm-wave 5G n257 and n258 bands. In simulations, the unit cell can maintain a phase difference of 180{\deg} +- 20{\deg} and a reflection magnitude greater than -2.8 dB within 22.7 to 30.5 GHz (29.3% bandwidth) using one-bit PIN switches. The proposed unit cell design with four circular cutouts and long vias could realize wideband performance by exciting two adjacent high-order resonances (2.5f and 3.5f). The periodic unit cells can maintain an angular stability of 30{\deg}. Based on the proposed unit cell, a 20 by 20 RIS array is designed and fabricated with a size of 7.1{\lambda} by 7.1{\lambda}. The measurement results demonstrate that the proposed RIS could maintain a 3 dB peak gain variation bandwidth among various array configurations within 22.5 to 29.5 GHz (26.9%) and with a beam scanning capability of 50{\deg}, making this design a good candidate for 5G mm-wave applications

    An investigation into the number and nature of the urgent care consultations managed and referred by community pharmacists in South-East England

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    Background: Community pharmacies are recognised as an under-utilised, accessible resource that could support the urgent care agenda. This study aimed to provide a snapshot of the number and nature of urgent care requests presented to a sample of community pharmacies in three counties in southern England, to determine how requests are managed, whether management is appropriate, as assessed by a group of experts, and whether customers receiving the care are satisfied with pharmacists’ interventions. Methods: A representative sample of pharmacists across the region was invited to keep a log-book documenting all urgent care requests over a two-week period. Data were analysed to estimate frequency and type of requests and to compare consultations in core and non-core hours. Log-book entries were scrutinised blind by an expert panel to determine appropriateness of pharmacist’s responses. Customers receiving pharmacists’ interventions were surveyed to assess satisfaction. Results: Seventeen pharmacies kept log-books detailing 432 urgent care consultations, equating to 13 consultations per pharmacy per week. Of these, 70% (n = 302) were dealt with by the pharmacist in-house with 30% (n = 130) resulting in referrals. Locum pharmacists were significantly more likely to refer to other NHS services than regular pharmacists. Over half the requests were for symptom management, skin problems presenting most commonly (38% of all symptoms presented). Forty-seven percent of consultations were considered to have ‘averted the need for other NHS services’. Pharmacists’ referral (but not assessment of urgency) was deemed appropriate by the expert panel in 90% of consultations. Ninety-five percent of customers surveyed were satisfied with the service and would use the pharmacy again. Conclusion: Extrapolating findings across the study population (approximately 4.4 million) suggests that community pharmacists manage over 11 500 urgent care consultations per week, with 8050 managed independently. These prevent approximately 5400 other NHS encounters, while also meeting customer expectations and expert panel endorsement

    Edge-centric multimodal authentication system using encrypted biometric templates

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    Data security, complete system control, and missed storage and computing opportunities in personal portable devices are some of the major limitations of the centralized cloud environment. Among these limitations, security is a prime concern due to potential unauthorized access to private data. Biometrics, in particular, is considered sensitive data, and its usage is subject to the privacy protection law. To address this issue, a multimodal authentication system using encrypted biometrics for the edge-centric cloud environment is proposed in this study. Personal portable devices are utilized for encrypting biometrics in the proposed system, which optimizes the use of resources and tackles another limitation of the cloud environment. Biometrics is encrypted using a new method. In the proposed system, the edges transmit the encrypted speech and face for processing in the cloud. The cloud then decrypts the biometrics and performs authentication to confirm the identity of an individual. The model for speech authentication is based on two types of features, namely, Mel-frequency cepstral coefficients and perceptual linear prediction coefficients. The model for face authentication is implemented by determining the eigenfaces. The final decision about the identity of a user is based on majority voting. Experimental results show that the new encryption method can reliably hide the identity of an individual and accurately decrypt the biometrics, which is vital for errorless authentication

    A fully-printed 3D antenna with 92% quasi-isotropic and 85% CP coverage

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    Internet of things (IoT) applications require orientation insensitive wireless devices to maintain stable and reliable communication. For those reasons, antennas providing a wide quasi-isotropic and circular polarization (CP) coverage are very attractive. However, achieving a wide quasi-isotropic and CP coverage simultaneously is challenging. In this work, we show that properly designed sloped dipoles on a 3D structure can maximize the CP coverage (theoretically up to 100%) even with equal-phased feed to the dipole elements. We derive the conditions and present the design graphs for the optimum slope angle for the dipole elements on a 3D hexagonal-shaped package to achieve a wide quasi-isotropic and CP coverage simultaneously. Based on the proposed theory, a practical antenna has been designed and fabricated using additive manufacturing. The measured results demonstrate a 7dB-isotropy of 92% and a CP coverage of 85%, which matches well with the predicted results from the theoretical analysis and full-wave simulations

    OPTIMIZATION OF ANN-BASED MODELS AND ITS EM CO-SIMULATION FOR PRINTED RF DEVICES

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    Printed VO2 RF switch founds immense potential in RF reconfigurable applications. However, their generic electrical equivalent model is still intangible that can be further integrated in CAD tools and utilize for simulation, analysis and design of RF/microwave circuits and systems. The artificial neural network (ANN) has been gaining popularity in modeling various types of RF components. However, most of these works merely demonstrate the establishment of the ANN-based RF model in the MATLAB environment without involving significant optimization. Furthermore, the integration of such ANN-based RF models in the EM and circuit simulator as well as the co-simulation between the ANN-based model and conventional models have not been demonstrated or validated. Therefore, the earlier reported models are still one step removed from its real RF applications. In this work, by using the fully printed vanadium dioxide (VO2) RF switch as the modeling example, a systematic hyperparameter optimization process has been conducted. Compared to the nonoptimized ANN model, a dramatic improvement in the model's accuracy has been observed for the ANN model with fully optimized hyperparameters. A correlation coefficient of more than 99.2% for broad frequency range demonstrates the accuracy of the modeling technique. In addition, we have also integrated the Python-backed ANN-based model into Advanced Design System (ADS), where a reconfigurable T-resonator band stop filter is used as an example to demonstrate the co-simulation between the ANN-based model and the conventional lumped-based model

    General practice pharmacists in England : integration, mediation and professional dynamics

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    Background: A number of key publications in recent years have advocated a more integrated vision of UK primary care involving increased multi-professional communication and understanding. This has resulted in a marked change in the roles being undertaken by pharmacists. Community pharmacists have traditionally provided a medicine supply function and treated minor ailments in addition to delivering a suite of locally commissioned services; however these functions have not necessarily been part of a programme of care involving the other clinicians associated with the patient. An integrated model of care would see much closer working between pharmacy and general practice but also with pharmacists not only working with, but in the practice, in an enhanced patient-facing role, trained as independent prescribers. This has implications for the dynamics amongst professionals in this environment. Objectives: This exploratory multiple case study attempts to explore these changing dynamics across ten GP surgeries throughout the South-East of England. Methods: Semi-structured, in-depth interviews were conducted with one nurse, one pharmacist and one physician from each clinic, and survey data was collected from 38 patients who had appointments with a pharmacist. Results: The data suggested that the pharmacists who had enhanced roles perceived some uncertainty about their professional role and identity, which resulted in instability and insecurity and that this uncertainty led to both professional and interprofessional tension with their primary care colleagues. The survey data revealed that n = 35 (92%) patients stated they were 'very satisfied' or 'satisfied' with their appointment. And n = 37 (97%) were 'very comfortable' or 'comfortable' discussing their medications with the pharmacist. In addition, 36 patients (95%) reported that they strongly agreed or agreed with the clinical recommendations made by the pharmacist. Conclusions: These findings are discussed in relation to role expansion and professional/interprofessional relations before key practical suggestions are offered. Keywords: Enhanced pharmacists' role; Integration; Primary healthcare; Professional dynamics

    Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions
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