Reducing the Download Time in Stochastic P2P Content Delivery Networks by Improving Peer Selection

Peer-to-peer (P2P) applications have become a popular method for obtaining digital content. Recent research has shown that the amount of time spent downloading from a poor performing peer effects the total download duration. Current peer selection strategies attempt to limit the amount of time spent downloading from a poor performing peer, but they do not use both advanced knowledge and service capacity after the connection has been made to aid in peer selection. Advanced knowledge has traditionally been obtained from methods that add additional overhead to the P2P network, such as polling peers for service capacity information, using round trip time techniques to calculate the distance between peers, and by using tracker peers. This work investigated the creation of a new download strategy that replaced the random selection of peers with a method that selects server peers based on historic service capacity and ISP in order to further reduce the amount of time needed to complete a download session. Peer-to-peer (P2P) applications have become a popular method for obtaining digital content. Recent research has shown that the amount of time spent downloading from a poor performing peer effects the total download duration. Current peer selection strategies attempt to limit the amount of time spent downloading from a poor performing peer, but they do not use both advanced knowledge and service capacity after the connection has been made to aid in peer selection. Advanced knowledge has traditionally been obtained from methods that add additional overhead to the P2P network, such as polling peers for service capacity information, using round trip time techniques to calculate the distance between peers, and by using tracker peers. This work investigated the creation of a new download strategy that replaced the random selection of peers with a method that selects server peers based on historic service capacity and ISP in order to further reduce the amount of time needed to complete a download session. The results of this new historic based peer selection strategy have shown that there are benefits in using advanced knowledge to select peers and only replacing the worst performing peers. This new approach showed an average download duration improvement of 16.6% in the single client simulation and an average cross ISP traffic reduction of 55.17% when ISPs were participating in cross ISP throttling. In the multiple clients simulation the new approach showed an average download duration improvement of 53.31% and an average cross ISP traffic reduction of 88.83% when ISPs were participating in cross ISP throttling. This new approach also significantly improved the consistency of the download duration between download sessions allowing for the more accurate prediction of download times

Evaluating Total Environmental Impact for a Computing Infrastructure

In this paper we outline the results of a project to evaluate the total climate/carbon impact of a digital research infrastructure for a defined snapshot period. We outline the carbon model used to calculate the impact and the data collected to quantify that impact for a defined set of resources. We discuss the variation in potential impact across both the active and embodied carbon for computing hardware and produce a range of estimates on the amount of carbon equivalent climate impact for the snapshot period

Factors associated with maternal worry about her young child exhibiting choosy feeding behaviour

Choosiness in young children is a normal behaviour that sometimes worries parents. The study aimed to investigate factors that are associated with a mother being worried about her child’s choosy feeding behaviour. Parents of singleton children from the Avon Longitudinal Study of Parents and Children (n = 5710) completed a questionnaire assessing perception of their child’s choosy feeding behaviour at 15 months of age and whether this choosiness worried them. Feeding behaviours and practices throughout the first 15 months were captured. Multinomial logistic regression models with three levels of worry (not at all, a bit and greatly) as the dependent variables tested associations with variables from pregnancy and infancy. Half of the children (56%) were described as choosy at 15 months; of these 27% had mothers who were a bit worried and 5% greatly worried. Mothers showed greater odds of being worried if the child was first born, difficult to feed or refused solids by 6 months of age. Worried mothers had shown greater odds of introducing lumpy foods late (after 9 months). Feeding vegetables regularly by 6 months was associated with lower odds of worry at 15 months. Support and advice to parents at the start of complementary feeding could help to alleviate worry. Parents should be reassured that choosiness is a normal part of child development

Powering Ocean Giants: The Energetics of Shark and Ray Megafauna

Shark and ray megafauna have crucial roles as top predators in many marine ecosystems, but are currently among the most threatened vertebrates and, based on historical extinctions, may be highly susceptible to future environmental perturbations. However, our understanding of their energetics lags behind that of other taxa. Such knowledge is required to answer important ecological questions and predict their responses to ocean warming, which may be limited by expanding ocean deoxygenation and declining prey availability. To develop bioenergetics models for shark and ray megafauna, incremental improvements in respirometry systems are useful but unlikely to accommodate the largest species. Advances in biologging tools and modelling could help answer the most pressing ecological questions about these iconic species

Relationships between Reading Ability and Child Mental Health: Moderating Effects of Self-Esteem

Objective: Children with reading difficulties are at elevated risk for externalising (e.g., conduct disorder) and internalising (e.g., anxiety and depression) mental health problems. Reading ability is also negatively associated with self-esteem, a consistent predictor of child and adolescent mental health more broadly. This study examined whether self-esteem moderated and/or mediated relationships between reading ability and mental health. Method: One hundred and seventeen children (7-12 years) completed standardised reading assessments (Castles and Coltheart Test 2; CC2) and self-report measures of mental health (Strengths and Difficulties Questionnaire; SDQ) and self-esteem (Coopersmith Self-esteem Inventory). Non-verbal intelligence (IQ) was measured using the block design and matrix reasoning subscales of the Wechsler Abbreviated Scale of Intelligence, and was controlled for in all multivariate analyses. Results: Reading ability was negatively associated with internalising symptoms. This relationship was not moderated by self-esteem. Poor readers also reported more total difficulties and externalising symptoms, but only at low levels of self-esteem. There was no evidence that self-esteem mediated relationships between reading ability and mental health. Conclusions: Poor reading was associated with internalising symptoms. Self-esteem moderated the impact of reading ability on total difficulties and externalising symptoms, with high self-esteem buffering against negative impacts of poor reading. However, the reliability of the self-esteem scale used in the study was poor and findings need replication using a reliable and valid self-esteem measure, as well as other measures of child mental health. If replicated, future research should examine whether interventions aiming to improve self-esteem can reduce the risk of externalising problems in children with reading difficulties

The orbital theory of Pleistocene climate: support from a revised chronology of the marine d18O record

https://www.researchgate.net/publication/230891291_The_Orbital_Theory_of_Pleistocene_Climate_Support_frim_a_Revised_Chronology_of_the_Marine_d18O_Recor

Developing a New Generation of Integrated Micro-Spec Far Infrared Spectrometers for the EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM)

The current state of far-infrared astronomy drives the need to develop compact, sensitive spectrometers for future space and ground-based instruments. Here we present details of the $\rm \mu$-Spec spectrometers currently in development for the far-infrared balloon mission EXCLAIM. The spectrometers are designed to cover the $\rm 555 - 714\ \mu$m range with a resolution of $\rm R\ =\ \lambda / \Delta\lambda\ =\ 512$at the$\rm 638\ \mu$m band center. The spectrometer design incorporates a Rowland grating spectrometer implemented in a parallel plate waveguide on a low-loss single-crystal Si chip, employing Nb microstrip planar transmission lines and thin-film Al kinetic inductance detectors (KIDs). The EXCLAIM$\rm \mu$-Spec design is an advancement upon a successful$\rm R = 64\ \mu$-Spec prototype, and can be considered a sub-mm superconducting photonic integrated circuit (PIC) that combines spectral dispersion and detection. The design operates in a single$M{=}2$grating order, allowing one spectrometer to cover the full EXCLAIM band without requiring a multi-order focal plane. The EXCLAIM instrument will fly six spectrometers, which are fabricated on a single 150 mm diameter Si wafer. Fabrication involves a flip-wafer-bonding process with patterning of the superconducting layers on both sides of the Si dielectric. The spectrometers are designed to operate at 100 mK, and will include 355 Al KID detectors targeting a goal of NEP${\sim}8\times10^{-19}$$\rm W/\sqrt{Hz}$. We summarize the design, fabrication, and ongoing development of these$\rm \mu$-Spec spectrometers for EXCLAIM.Comment: 9 pages, 5 figures, to appear in the Proceedings of the SPIE Astronomical Telescopes + Instrumentation (2022

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure