4,348 research outputs found
Automated progress identification and feedback in large experimental laboratories
In this work we describe a novel web-based system whose aim is to enhance the learning environment within experimental laboratories, and report on its deployment in undergraduate computer architecture modules. Student progress is tracked and recorded throughout the practical work, and supervisory facilities are provided including the visualisation of the progress of everyone in the laboratory on a management console. The system delivers information concerning the practical work to be undertaken, and uses carefully designed sets of questions based on the observations to be made by students in the laboratory. The responses made in this system are used to feedback further specific information to the student to aid their individual progress
Testing Gravity-Driven Collapse of the Wavefunction via Cosmogenic Neutrinos
It is pointed out that the Diosi-Penrose ansatz for gravity-induced quantum
state reduction can be tested by observing oscillations in the flavor ratios of
neutrinos originated at cosmological distances. Since such a test would be
almost free of environmental decoherence, testing the ansatz by means of a next
generation neutrino detector such as IceCube would be much cleaner than by
experiments proposed so far involving superpositions of macroscopic systems.
The proposed microscopic test would also examine the universality of
superposition principle at unprecedented cosmological scales.Comment: 4 pages; RevTeX4; Essentially the version published in PR
The semiquinone radical anion of 1,10-phenanthroline-5,6-dione: synthesis and rare earth coordination chemistry
Reduction of 1,10-phenanthroline-5,6-dione (pd) with CoCpR2 resulted in the first molecular compounds of the pd˙− semi-quinone radical anion, [CoCpR2]+[pd]˙− (R = H, (1); R = Me4, (2)). Furthermore compounds 1 and 2 were reacted with [Y(hfac)3(thf)2] (hfac = 1,1,1-5,5,5-hexafluoroacetylacetonate) to synthesise the rare earth-transition metal heterometallic compounds, [CoCpR2]+[Y(hfac)3(N,N′-pd)]˙− (R = H, (3); R = Me4, (4))
Breaking scale invariance from a singular inflaton potential
In this paper we break the scale invariance of the primordial power spectrum
of curvature perturbations of inflation. Introducing a singular behaviour due
to spontaneous symmetry breaking in the inflaton potential, we obtain fully
analytic expressions of scale dependent oscillation and a modulation in power
on small scale in the primordial spectrum. And we give the associated cosmic
microwave background and matter power spectra which we can observe now and
discuss the signature of the scale dependence. We also address the possibility
of whether some inflationary model with featured potential might mimic the
predictions of the scale invariant power spectrum. We present some examples
which illustrate such degeneracies.Comment: 20 pages, 9 figures; Discussion expanded and references added;
Miscellaneous typos correcte
Far-infrared observations of young clusters embedded in the R Coronae Austrinae and RHO Ophiuchi dark clouds
Multicolor far infrared maps in two nearby dark clouds, R Coronae Austrinae and rho Ophiuchi, were made in order to investigate the individual contribution of low mass stars to the energetics and dynamics of the surrounding gas and dust. Emission from cool dust associated with five low mass stars in Cr A and four in rho Oph was detected; their far infrared luminosities range from 2 far infrared luminosities L. up to 40 far infrared luminosities. When an estimate of the bolometric luminosity was possible, it was found that typically more than 50% of the star's energy was radiated longward of 20 micrometers. meaningful limits to the far infrared luminosities of an additional eleven association members in Cr A and two in rho Oph were also obtained. The dust optical depth surrounding the star R Cr A appears to be asymmetric and may control the dynamics of the surrounding molecular gas. The implications of the results for the cloud energetics and star formation efficiency in these two clouds are discussed
Automated Text Abstraction from Documents and Webpages Metadata using Probabilistic Clusteringalgorithms
Annotations are comments, notes, explanations, tagsor other types of external remarks. Annotation can be added to a text document or few portions of document or to a webpage. Annotation helps effective information retrievals. Webpage metadata is the data related with website, it is machine understandable information about web resources or other tags.Collaborative annotations are based on user created tags to annotate new objects. These tags are related user created labels for entities and allows user to organize and index the contents. Tagging is the act of adding keywords to objects. There have been significant amount of work to be performed in coming up with the tags for text documents or other resources like webpages, images and videos. Automated Annotation System (AAS) which uses algorithms like K-Means and Distributed Hash Table (DHT) to automatically create the attribute or annotation from documents or metadata of webpages. This proposed annotation technique provides the processing of metadata and/or text to efficiently come up with annotations rather than manually understanding the metadata or analyzing the text
A massive warm baryonic halo in the Coma cluster
Several deep PSPC observations of the Coma cluster reveal a very large-scale
halo of soft X-ray emission, substantially in excess of the well known
radiation from the hot intra-cluster medium. The excess emission, previously
reported in the central region of the cluster using lower-sensitivity EUVE and
ROSAT data, is now evident out to a radius of 2.6 Mpc, demonstrating that the
soft excess radiation from clusters is a phenomenon of cosmological
significance. The X-ray spectrum at these large radii cannot be modeled
non-thermally, but is consistent with the original scenario of thermal emission
from warm gas at ~ 10^6 K. The mass of the warm gas is on par with that of the
hot X-ray emitting plasma, and significantly more massive if the warm gas
resides in low-density filamentary structures. Thus the data lend vital support
to current theories of cosmic evolution, which predict that at low redshift
\~30-40 % of the baryons reside in warm filaments converging at clusters of
galaxies.Comment: Astrophysical Journal, in pres
Multi-Terabyte EIDE Disk Arrays running Linux RAID5
High-energy physics experiments are currently recording large amounts of data
and in a few years will be recording prodigious quantities of data. New methods
must be developed to handle this data and make analysis at universities
possible. Grid Computing is one method; however, the data must be cached at the
various Grid nodes. We examine some storage techniques that exploit recent
developments in commodity hardware. Disk arrays using RAID level 5 (RAID-5)
include both parity and striping. The striping improves access speed. The
parity protects data in the event of a single disk failure, but not in the case
of multiple disk failures.
We report on tests of dual-processor Linux Software RAID-5 arrays and
Hardware RAID-5 arrays using a 12-disk 3ware controller, in conjunction with
250 and 300 GB disks, for use in offline high-energy physics data analysis. The
price of IDE disks is now less than $1/GB. These RAID-5 disk arrays can be
scaled to sizes affordable to small institutions and used when fast random
access at low cost is important.Comment: Talk from the 2004 Computing in High Energy and Nuclear Physics
(CHEP04), Interlaken, Switzerland, 27th September - 1st October 2004, 4
pages, LaTeX, uses CHEP2004.cls. ID 47, Poster Session 2, Track
Intelligent assistance in scientific data preparation
Scientific data preparation is the process of extracting usable scientific data from raw instrument data. This task involves noise detection (and subsequent noise classification and flagging or removal), extracting data from compressed forms, and construction of derivative or aggregate data (e.g. spectral densities or running averages). A software system called PIPE provides intelligent assistance to users developing scientific data preparation plans using a programming language called Master Plumber. PIPE provides this assistance capability by using a process description to create a dependency model of the scientific data preparation plan. This dependency model can then be used to verify syntactic and semantic constraints on processing steps to perform limited plan validation. PIPE also provides capabilities for using this model to assist in debugging faulty data preparation plans. In this case, the process model is used to focus the developer's attention upon those processing steps and data elements that were used in computing the faulty output values. Finally, the dependency model of a plan can be used to perform plan optimization and run time estimation. These capabilities allow scientists to spend less time developing data preparation procedures and more time on scientific analysis tasks
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