26,828 research outputs found
Jason-1/Jason-2 metocean comparisons and monitoring
No full textThe initial tandem phase of the Jason-2 mission is important for the calibration of the entire altimetric system, not just the records of sea surface height. However, as well as allowing a bulk comparison of metocean parameters such as wave height and backscatter strength (used to infer wind speed), it affords a more detailed opportunity to understand the artefacts within each instrument. The wave height comparison shows no bias between the instruments, with the mismatch error of consecutive points independent of one another. The backscatter difference is not a simple offset, but has a trend with weak non-linear variations. The technique for backscatter monitoring using Ku-/C-band differences is validated during the tandem phase, and extended to show ~59-day oscillations throughout the Jason-1 mission. This effect, which is predominantly in the C-band, is related to changing solar exposure, due to the fraction of orbit in eclipse varying as the orbit precesses. Such anomalies were partially present in TOPEX-B data, but are not noticeable for Jason-2. It is recommended that all TOPEX, Jason-1 and Jason-2 data be transformed to a consistent scale, allowing for the bias and trend terms in the offsets between instruments, and correcting for any long-period drifts in individual calibration; this will enable a single wind speed algorithm to be applied to the combined satellite data
On time series clustering with k-means
No full textThere is a long history of research into time series clustering using distance-based partitional clustering. Many of the most popular algorithms adapt k-means (also known as Lloyd's algorithm) to exploit time dependencies in the data by specifying a time series distance function. However, these algorithms are often presented with k-means configured in various ways, altering key parameters such as the initialisation strategy. This variability makes it difficult to compare studies because k-means is known to be highly sensitive to its configuration. To address this, we propose a standard Lloyd's-based model for TSCL that adopts an end-to-end approach, incorporating a specialised distance function not only in the assignment step but also in the initialisation and stopping criteria. By doing so, we create a unified structure for comparing seven popular Lloyd's-based TSCL algorithms. This common framework enables us to more easily attribute differences in clustering performance to the distance function itself, rather than variations in the k-means configuration
Lines of Credit and Consumption Smoothing: The Choice between Credit Cards and Home Equity Lines of Credit
No full textThe author models the choice between credit cards and home equity lines of credit (HELOCs) within a framework where consumers hold lines of credit as instruments of consumption smoothing across state and time. Flexible repayment schemes for lines of credit induce risk-averse consumers with sufficiently high discount rates to underinsure and hold lines of credit instead as a buffer, even when they have access to full and fair insurance markets. Weighing the fixed upfront fees and higher default costs of HELOCs against the advantages of low and income-tax-deductible interest payments, the author finds a threshold level of potential borrowing belowwhich consumers prefer to use credit cards exclusively. Above that threshold, consumers decide touse HELOCs and consolidate all outstanding credit card debt into them; however, a rising probability of default and the resulting loss of equity in the home will put an upper bound on the potential HELOC borrowing that will prevent full debt consolidation.Credit and credit aggregates
“The Support Continuum” Exploring how support workers understand their role in supporting adults with learning disabilities to use the internet for personal and sexual relationships Jason Lines
No full textWith internet use prominent in daily life, research investigating how adults with learning disabilities are accessing and using the internet is increasingly relevant. Three papers are presented in this thesis which aimed to provide additional understanding about this research topic.
The first paper outlines a review of the literature regarding what factors influence how adults with intellectual disabilities access and use the internet. The existing literature suggests a shift in the technology used to access the internet, from computers to smartphones. It also shows a shift in the purpose of internet use, from only using the internet for emails, to multi-platform usage, mainly social media. Significantly, it highlighted how important it is for some adults with learning disabilities to have access to support to assist with using the internet; in addition, the perceptions of those supporting impacted on how much support a person would receive.
The second paper details the empirical research that was undertaken in response to findings from the literature review. Eight support workers took part in this qualitative study which looked at how support workers understand their role supporting adults with learning disabilities to use the internet for personal and sexual relationships. Interviews were transcribed and analysed using thematic analysis. The themes of ‘Social and Organisational dilemmas’ with subthemes ‘Role and Moral positioning’, ‘Expectations of Support’ and ‘Protected and Reflective space; ‘Policy dilemmas’ and ‘Power and position’ were found and discussed. This research highlighted the current gap in training and guidance available for support workers regarding supporting people to use the internet for personal and sexual relationships – suggesting more must be done to develop these training opportunities.
The final paper is an executive summary which condenses the empirical research and presents it in a format accessible to adults with learning disabilities, support workers, and organisations employing support workers
HIVE-COTE 2.0: a new meta ensemble for time series classification
No full textThe Hierarchical Vote Collective of Transformation-based Ensembles (HIVE-COTE) is a heterogeneous meta ensemble for time series classification. HIVE-COTE forms its ensemble from classifiers of multiple domains, including phase-independent shapelets, bag-of-words based dictionaries and phase-dependent intervals. Since it was first proposed in 2016, the algorithm has remained state of the art for accuracy on the UCR time series classification archive. Over time it has been incrementally updated, culminating in its current state, HIVE-COTE 1.0. During this time a number of algorithms have been proposed which match the accuracy of HIVE-COTE. We propose comprehensive changes to the HIVE-COTE algorithm which significantly improve its accuracy and usability, presenting this upgrade as HIVE-COTE 2.0. We introduce two novel classifiers, the Temporal Dictionary Ensemble (TDE) and Diverse Representation Canonical Interval Forest (DrCIF), which replace existing ensemble members. Additionally, we introduce the Arsenal, an ensemble of ROCKET classifiers as a new HIVE-COTE 2.0 constituent. We demonstrate that HIVE-COTE 2.0 is significantly more accurate than the current state of the art on 112 univariate UCR archive datasets and 26 multivariate UEA archive datasets
Electrocution of raptors at power lines in Central Kazakhstan
No full textAlong three transects of medium voltage power lines in the steppe of Central Kazakhstan, surveys for bird casualties were carried out in summer 2006 in order to estimate the quantitative and qualitative impact of power lines on bird mortality in this area. In total, 409 dead birds of 34 different species were found. Raptors represented 44 % of the total (179 individuals, 10 species). Most of them died due to electrocution. The proportion of raptors strongly varied between early and late summer, the increase in August suggests that especially young birds are prone to electrocution. The density of raptor casualties varied from 0.1 to 7.6 birds per line km and month. Adverse effects of power lines on bird life could be avoided by changing the pole construction (use of suspended insulators) or protective measures (e. g. caps).Zur Bestimmung des qualitativen und quantitativen Ausmaßes des Stromtodes von Vögeln in Zentralkasachstan wurden im Sommer 2006 Transektzählungen entlang von drei Mittelspannungsleitungen in dieser Region durchgeführt. Insgesamt wurden 409 tote Vögel (34 verschiedene Arten) gefunden, davon 44 % Greifvögel (179 Individuen, 10 Arten). Der Großteil starb durch Elektrokution. Der Anteil der Greifvögel variierte stark zwischen Früh- und Spätsommer. Der Anstieg im August lässt vermuten, dass Jungvögel besonders gefährdet sind. Die Greifvogeldichte betrug zwischen 0,1 und 7.6 Vögel pro Transekt-km und Monat. Durch veränderte Mastenkonstruktion (hängende Isolatoren) oder Schutzmaßnahmen (isolierende Hauben) kann viel zum Vogelschutz beigetragen werden
Lines of Inquiry
No full textThe author plots lines in spacetimes and finds implications for the (re)tracings of a family life lived through a landscape, and a landscape lived through family life.</jats:p
90 degree Inclined Pulsar
No full textCurrent sheet and open field lines with footpoints near the edge of the polar cap. The magnetic axis is inclined relative to the rotation axis by 90 degrees. Red field lines originate on the north polar cap and green field lines in the right panel originate on the south polar cap. Purple and grey colors indicate positive and negative net local charge density in the current sheet, which is shown between 1.2-2 light cylinder radii
60 degree Inclined Pulsar
No full textCurrent sheet and open field lines with footpoints near the edge of the polar cap. The magnetic axis is inclined relative to the rotation axis by 60 degrees. Red
field lines originate on the north polar cap and green field lines in the right panel originate on the south polar cap. Purple and grey colors indicate positive and negative net
local charge density in the current sheet, which is shown between 1.2-2 light cylinder radii
Dynamical Magnetic Fields of Antialigned Nonspinning Dipoles
No full textThis movie shows the dynamical behavior of field lines seeded on one of the stars. We find
a clear cyclical process operating in the magnetosphere. First, field lines from one star can attach to the second star. Second, as the orbit progresses these field lines
develop twist and are expelled outward past the second
star as closed loops. Third, these loops open up to infinity and then reconnect on the far side of the first star
opposite to the second. Fourth, the orbital motion will
bring the second star back into contact with the closed
loops, and they reattach to the second star
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