465 research outputs found

    Performance of an adaptive multimedia mechanism in a wireless multi-user environment

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    With the increasing popularity of accessing multimedia services over different wireless networks, researchers have been trying to develop different adaptive multimedia mechanisms in order to mitigate the impact of fluctuating radio resources. This paper considers the case when multiple users stream video over the same IEEE 802.11b WLAN using a newly proposed Signal Strength-based Adaptive Multimedia Delivery Mechanism (SAMMy). SAMMy makes use of the IEEE 802.11k standard and uses estimated signal strength, location, and packet loss as part of its adaptive mechanism in order to increase user perceived quality for multimedia streaming applications in wireless networks. SAMMy is evaluated by modeling and simulations and compared with another adaptive multimedia delivery mechanism TFRC, in terms of aggregate throughput and fairness. The results show that the proposed signal strengthbased adaptive multimedia delivery scheme outperforms the other scheme in terms of both throughput and fairness when performing video streaming in WLAN

    Power-friendly access network selection strategy for heterogeneous wireless multimedia networks

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    Apart from the number and types of applications available to users of diverse devices with various characteristics, a highly relevant issue in current and future wireless environment is the coexistence of multiple networks supported by various access technologies deployed by different operators. In this context, the aim is to keep the mobile users “always best connected” anywhere and anytime in such a multi-technology multi-application multi-terminal multi-user environment. Multimedia streaming to battery powered mobile devices has become widespread. However, the battery power capability has not kept up with the advances in other technologies and it is rapidly becoming a concern. Since multimedia applications are known to be high energy consumers and since the battery lifetime is an important factor for mobile users, this paper proposes a network selection algorithm which bases its decision on the estimated energy consumption. The proposed solution enables the multimedia stream to last longer while maintaining an acceptable user perceived quality by selecting the least power consuming network

    On the impact of wireless network traffic location and access technology on the mobile device energy consumption

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    In the context of wireless user’s increasing demands for better device power and battery management, this paper investigates some factors that can impact the power consumption on the energy consumption of mobile devices. The focus is on two factors when performing multimedia streaming: the impact of the traffic location within a WLAN; and the impact of the radio access network technology (WLAN, HSDPA, UMTS). The energy measurement results show that by changing the quality level of the multimedia stream the energy can be greatly conserved while the user perceived quality level is still acceptable. Moreover, by using the cellular interface much more energy is consumed (up to 61%) than by using the WLAN interface

    Quality utility modelling for multimedia applications for Android mobile devices

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    With the advances in mobile technologies, smart mobile computing devices have become increasingly affordable and powerful, leading to a significant growth in both the number of advanced mobile users and their bandwidth demands. Moreover multimedia streaming to these high-end mobile devices has become widespread. However, multimedia applications are known to be resource-hungry and in order to cope with this explosion of data traffic, operators have started deploying different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to ensure an Always Best Experience to the mobile user, anywhere and anytime. This paper proposes the Quality Utility, a realistic mapping function of the received bandwidth to user satisfaction for multimedia streaming applications. The Quality Utility is mapped to a Google Nexus One Android Mobile device and validated through objective and subjective tests

    Experiments with a Malkus-Lorenz water wheel: Chaos and Synchronization

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    We describe a simple experimental implementation of the Malkus-Lorenz water wheel. We demonstrate that both chaotic and periodic behavior is found as wheel parameters are changed in agreement with predictions from the Lorenz model. We furthermore show that when the measured angular velocity of our water wheel is used as an input signal to a computer model implementing the Lorenz equations, high quality chaos synchronization of the model and the water wheel is achieved. This indicates that the Lorenz equations provide a good description of the water wheel dynamics.Comment: 12 pages, 7 figures. The following article has been accepted by the American Journal of Physics. After it is published, it will be found at http://scitation.aip.org/ajp

    Acceptance and understanding of artificial intelligence in medical research among orthopaedic surgeons

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    AimsThe principles of evidence-based medicine (EBM) are the foundation of modern medical practice. Surgeons are familiar with the commonly used statistical techniques to test hypotheses, summarize findings, and provide answers within a specified range of probability. Based on this knowledge, they are able to critically evaluate research before deciding whether or not to adopt the findings into practice. Recently, there has been an increased use of artificial intelligence (AI) to analyze information and derive findings in orthopaedic research. These techniques use a set of statistical tools that are increasingly complex and may be unfamiliar to the orthopaedic surgeon. It is unclear if this shift towards less familiar techniques is widely accepted in the orthopaedic community. This study aimed to provide an exploration of understanding and acceptance of AI use in research among orthopaedic surgeons.MethodsSemi-structured in-depth interviews were carried out on a sample of 12 orthopaedic surgeons. Inductive thematic analysis was used to identify key themes.ResultsThe four intersecting themes identified were: 1) validity in traditional research, 2) confusion around the definition of AI, 3) an inability to validate AI research, and 4) cautious optimism about AI research. Underpinning these themes is the notion of a validity heuristic that is strongly rooted in traditional research teaching and embedded in medical and surgical training.ConclusionResearch involving AI sometimes challenges the accepted traditional evidence-based framework. This can give rise to confusion among orthopaedic surgeons, who may be unable to confidently validate findings. In our study, the impact of this was mediated by cautious optimism based on an ingrained validity heuristic that orthopaedic surgeons develop through their medical training. Adding to this, the integration of AI into everyday life works to reduce suspicion and aid acceptance.Cite this article: Bone Jt Open 2023;4(9):696–703

    Economic evaluation of ‘Men on the Move’, a ‘real world’ community-based physical activity programme for men

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    Background Physical activity (PA) interventions capable of producing health benefits cost effectively are a public health priority across the Western world. ‘Men on the Move’ (MOM), a community-based PA intervention for men, demonstrated significant health benefits up to 52-weeks (W) post-baseline. This article details the economic evaluation of MOM with a view to determining its cost-effectiveness as a public health intervention to be rolled out nationally in Ireland. Methods Cost-effectiveness was determined by comparing the costs (direct and indirect) of the programme to its benefits, which were captured as the impact on quality-adjusted life-years (QALYs). For the benefits, cost–utility analysis was conducted by retrospectively adapting various health-related measures of participants to generate health states using Brazier et al.’s (2002) short form-6D algorithm. This in turn allowed for ‘utility measures’ to be generated, from which QALYs were derived. Results Findings show MOM to be cost-effective in supporting an ‘at risk’ cohort of men achieves significant improvements in aerobic fitness, weight loss and waist reduction. The total cost per participant (€125.82 for each of the 501 intervention participants), the QALYs gained (11.98 post-12-W intervention, or 5.3% health improvement per participant) and estimated QALYs ratio costs of €3723 represents a cost-effective improvement when compared to known QALY guidelines. Conclusions The analysis shows that the cost per QALY achieved by MOM is significantly less than the existing benchmarks of £20 000 and €45 000 in the UK and Ireland respectively, demonstrating MOM to be cost-effective

    Intestinal-derived FGF15 protects against deleterious effects of vertical sleeve gastrectomy in mice

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    Bariatric surgeries such as the Vertical Sleeve Gastrectomy (VSG) are invasive but provide the most effective improvements in obesity and Type 2 diabetes. We hypothesized a potential role for the gut hormone Fibroblast-Growth Factor 15/19 which is increased after VSG and pharmacologically can improve energy homeostasis and glucose handling. We generated intestinal-specific FGF15 knockout (FGF15INT-KO) mice which were maintained on high-fat diet. FGF15INT-KO mice lost more weight after VSG as a result of increased lean tissue loss. FGF15INT-KO mice also lost more bone density and bone marrow adipose tissue after VSG. The effect of VSG to improve glucose tolerance was also absent in FGF15INT-KO. VSG resulted in increased plasma bile acid levels but were considerably higher in VSG-FGF15INT-KO mice. These data point to an important role after VSG for intestinal FGF15 to protect the organism from deleterious effects of VSG potentially by limiting the increase in circulating bile acids.http://deepblue.lib.umich.edu/bitstream/2027.42/169579/2/s41467-021-24914-y.pdfAccepted versio

    The Red Sea, Coastal Landscapes, and Hominin Dispersals

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    This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization

    European guidelines (S3) on diagnosis and management of mucous membrane pemphigoid, initiated by the European Academy of Dermatology and Venereology – Part I

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    This guideline on mucous membrane pemphigoid (MMP) has been elaborated by the Task Force for Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology (EADV) with a contribution of physicians from all relevant disciplines and patient organizations. It is a S3 consensus-based guideline encompassing a systematic review of the literature until June 2019 in the MEDLINE and EMBASE databases. This first part covers methodology, the clinical definition of MMP, epidemiology, MMP subtypes, immunopathological characteristics, disease assessment and outcome scores. MMP describes a group of autoimmune skin and mucous membrane blistering diseases, characterized by a chronic course and by predominant involvement of the mucous membranes, such as the oral, ocular, nasal, nasopharyngeal, anogenital, laryngeal and oesophageal mucosa. MMP patients may present with mono- or multisite involvement. Patients’ autoantibodies have been shown to be predominantly directed against BP180 (also called BPAG2, type XVII collagen), BP230, laminin 332 and type VII collagen, components of junctional adhesion complexes promoting epithelial stromal attachment in stratified epithelia. Various disease assessment scores are available, including the Mucous Membrane Pemphigoid Disease Area Index (MMPDAI), the Autoimmune Bullous Skin disorder Intensity Score (ABSIS), the ‘Cicatrising Conjunctivitis Assessment Tool’ and the Oral Disease Severity Score (ODSS). Patient-reported outcome measurements (PROMs), including DLQI, ABQOL and TABQOL, can be used for assessment of quality of life to evaluate the effectiveness of therapeutic interventions and monitor disease course
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