11,131 research outputs found
Experiences of teaching UML within the information systems curriculum
The Unified Modelling Language (UML) has been a standard modelling language for the development of software intensive systems since 2000. As a consequence, the information systems (IS) curriculum, at the Cavendish School of Computer Science, University of Westminster in London, had UML teaching incorporated two years ago. We have encouraged the introduction to and use of UML in modules that replaced traditional approaches to IS development. In this paper we report on experiences of using UML within the two modules of our undergraduate curriculum, delivered by the IS department. The first module is taught in the second year, i.e. at level 5, and delivers requirements analysis with UML. The second module uses the UML for modelling and designing distributed business applications and is taught in the final year, at level 6. In both modules it is assumed that an introduction to modelling in IS, with the syntax and semantics of a selection of UML modelling elements and diagrams, has been done earlier. We single out some problems and give a rationale for changes in the next academic yea
Experiences of revalidating the undergraduate and postgraduate courses within the information systems curricula at University of Westminster, UK
Information systems (IS) is the commonly accepted title for academic programs focusing on applied information technology provided by a range of Universities in the UK. The University of Westminster based in central London has successfully run BSc and MSc courses in IS for more than a decade. The courses underwent a major revision in 2002 focusing on subject content, construction of courses and teaching/learning strategies. We address the purpose of course reviews within the UK higher education (HE) environment, gives a rationale for our curriculum changes, describes the revalidated IS courses at both BSc and MSc levels including our teaching and assessment strategies, and comments on our progress to date
Magnetic phase diagram of the antiferromagnetic pyrochlore Gd2Ti2O7
Gd2Ti2O7 is a highly frustrated antiferromagnet on a pyrochlore lattice,
where apart from the Heisenberg exchange the spins also interact via
dipole-dipole forces. We report on low-temperature specific heat measurements
performed on single crystals of Gd2Ti2O7 for three different directions of an
applied magnetic field. The measurements reveal the strongly anisotropic
behaviour of Gd2Ti2O7 in a magnetic field despite the apparent absence of a
significant single-ion anisotropy for Gd3+. The H-T phase diagrams are
constructed for H//111], H//[110] and H//[112]. The results indicate that
further theoretical work beyond a simple mean-field model is required.Comment: 4 figure
Crystal growth and properties of the non-centrosymmetric superconductor, Ru7B3
We describe the crystal growth of high quality single crystals of the
non-centrosymmetric superconductor, Ru7B3 by the floating zone technique, using
an optical furnace equipped with xenon arc lamps. The crystals obtained are
large and suitable for detailed measurements, and have been examined using
x-ray Laue patterns. The superconducting properties of the crystals obtained
have been investigated by magnetisation and resistivity measurements. Crystals
have also been grown starting with enriched 11B isotope, making them suitable
for neutron scattering experiments.Comment: 4 pages, 5 figures. Accepted for publication in Journal of Crystal
Growt
Superconducting and normal-state properties of the noncentrosymmetric superconductor Re6Zr
We systematically investigate the normal and superconducting properties of
non-centrosymmetric ReZr using magnetization, heat capacity, and
electrical resistivity measurements. Resistivity measurements indicate
ReZr has poor metallic behavior and is dominated by disorder. ReZr
undergoes a superconducting transition at K. Magnetization measurements give a lower critical
field, mT. The
Werthamer-Helfand-Hohenberg model is used to approximate the upper critical
field T which is close to
the Pauli limiting field of 12.35 T and which could indicate singlet-triplet
mixing. However, low-temperature specific-heat data suggest that ReZr is
an isotropic, fully gapped s-wave superconductor with enhanced electron-phonon
coupling. Unusual flux pinning resulting in a peak effect is observed in the
magnetization data, indicating an unconventional vortex state.Comment: 11 pages, 7 figures, 2 table
Comparative study of the centrosymmetric and non-centrosymmetric superconducting phases of Re3W using muon-spin spectroscopy and heat capacity measurements
We compare the low-temperature electronic properties of the centrosymmetric
(CS) and non-centrosymmetric (NCS) phases of Re3W using muon-spin spectroscopy
and heat capacity measurements. The zero-field muSR results indicate that
time-reversal symmetry is preserved for both structures of Re3W.
Transverse-field muon spin rotation has been used to study the temperature
dependence of the penetration depth lambda(T) in the mixed state. For both
phases of Re3W, lambda(T) can be explained using a single-gap s-wave BCS model.
The magnetic penetration depth at zero temperature, lambda(0), is 164(7) and
418(6) nm for the centrosymmetric and the non-centrosymmetric phases of Re3W
respectively. Low-temperature specific heat data also provide evidence for an
s-wave gap-symmetry for the two phases of Re3W. Both the muSR and heat capacity
data show that the CS material has a higher Tc and a larger superconducting gap
Delta(0) at 0 K than the NCS compound. The ratio Delta(0)/kBTc indicates that
both phases of Re3W should be considered as strong-coupling superconductors.Comment: 7 pages, to appear in Physical Review
Contemporary outcome measures in acute stroke research: choice of primary outcome measure
BACKGROUND AND PURPOSE:
The diversity of available outcome measures for acute stroke trials is challenging and implies that the scales may be imperfect. To assist researchers planning trials and to aid interpretation, this article reviews and makes recommendations on the available choices of scales. The aim is to identify an approach that will be universally accepted and that should be included in most acute trials, without seeking to restrict options for special circumstances.
METHODS:
The article considers outcome measures that have been widely used or are currently advised. It examines desirable properties for outcome measures such as validity, relevance, responsiveness, statistical properties, availability of training, cultural and language issues, resistance to comorbidity, as well as potential weaknesses. Tracking and agreement among outcomes are covered.
RESULTS:
Typical ranges of scores for the common scales are described, along with their statistical properties, which in turn influence optimal analytic techniques. The timing of recovery on scores and usual practice in trial design are considered.
CONCLUSIONS:
The preferred outcome measure for acute trials is the modified Rankin Scale, assessed at 3 months after stroke onset or later. The interview should be conducted by a certified rater and should involve both the patient and any relevant caregiver. Incremental benefits at any level of the modified Rankin Scale may be acceptable. The modified Rankin Scale is imperfect but should be retained in its present form for comparability with existing treatment comparisons. No second measure should be required, but correlations with supporting scales may be used to confirm consistency in direction of effects on other measures
Speech Analysis
Contains research objectives and reports on one research project.National Science Foundatio
Superconducting and magnetic properties of Sr3Ir4Sn13
Magnetization and muon spin relaxation or rotation (muSR) measurements have
been performed to study the superconducting and magnetic properties of
Sr3Ir4Sn13. From magnetization measurements the lower and upper critical fields
of Sr3Ir4Sn13 are found to be 81(1) Oe and 14.4(2) kOe, respectively.
Zero-field muSR data show no sign of any magnetic ordering or weak magnetism in
Sr3Ir4Sn13. Transverse-field muSR measurements in the vortex state provided the
temperature dependence of the magnetic penetration depth. The dependence of
penetration depth with temperature is consistent with the existence of single
s-wave energy gap in the superconducting state of Sr3Ir4Sn13 with a gap value
of 0.82(2) meV at absolute zero temperature. The magnetic penetration depth at
zero temperature is 291(3) nm. The gap to Tc ratio is 2.1(1), indicates that
Sr3Ir4Sn13 should be considered as a strong-coupling superconductor.Comment: 6 pages, 5 figure
Probing the superconducting ground state of the noncentrosymmetric superconductors CaTSi3 (T = Ir, Pt) using muon-spin relaxation and rotation
The superconducting properties of CaTSi3 (where T = Pt and Ir) have been
investigated using muon spectroscopy. Our muon-spin relaxation results suggest
that in both these superconductors time-reversal symmetry is preserved, while
muon-spin rotation data show that the temperature dependence of the superfluid
density is consistent with an isotropic s-wave gap. The magnetic penetration
depths and upper critical fields determined from our transverse-field muon-spin
rotation spectra are found to be 448(6) and 170(6) nm, and 3800(500) and
1700(300) G, for CaPtSi3 and CaIrSi3 respectively. The superconducting
coherence lengths of the two materials have also been determined and are 29(2)
nm for CaPtSi3 and 44(4) nm for CaIrSi3.Comment: 6 pages, 7 figure
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