22,700 research outputs found
From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems
At a time when many companies are under pressure to reduce "times-to-market"
the management of product information from the early stages of design through
assembly to manufacture and production has become increasingly important.
Similarly in the construction of high energy physics devices the collection of
(often evolving) engineering data is central to the subsequent physics
analysis. Traditionally in industry design engineers have employed Engineering
Data Management Systems (also called Product Data Management Systems) to
coordinate and control access to documented versions of product designs.
However, these systems provide control only at the collaborative design level
and are seldom used beyond design. Workflow management systems, on the other
hand, are employed in industry to coordinate and support the more complex and
repeatable work processes of the production environment. Commercial workflow
products cannot support the highly dynamic activities found both in the design
stages of product development and in rapidly evolving workflow definitions. The
integration of Product Data Management with Workflow Management can provide
support for product development from initial CAD/CAM collaborative design
through to the support and optimisation of production workflow activities. This
paper investigates this integration and proposes a philosophy for the support
of product data throughout the full development and production lifecycle and
demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure
Payments for Ecosystem Services: Legal and Institutional Frameworks
Analysis and engagement with partners working on ecosystem services transactions, policies and laws over the past 10 years have demonstrated a clear need to better understand the legal and institutional frameworks that have the potential to promote or hinder the development of payments for ecosystem services (PES) schemes, as well as the complex legal considerations that affect ecosystem services projects. In response, the IUCN Environmental Law Centre and The Katoomba Group have worked on a joint initiative to analyze the legal and institutional frameworks of water-related PES schemes and projects in four Andean countries: South America (Northeastern)-Brazil; Bolivia, Colombia and Peru. It has resulted in this report. Country-based analysts with experience in ecosystem services transactions have developed country and project assessments to define existing and recommend future regulatory and institutional frameworks that enable equitable and long-lasting ecosystem services transactions. Partners from North America (Central America)-Costa Rica; North America-Mexico; Ecuador and the North America-United States provided feedback on the assessments. The country assessments yielded lessons which were used to develop a set of recommendations on legal frameworks, property rights, enabling institutions, PES contracts, and governance issues supporting the future development of PES schemes
Resolving the Sin(I) degeneracy in Low-Mass Multi-Planet Systems
Long-term orbital evolution of multi-planet systems under tidal dissipation
often converges to a stationary state, known as the tidal fixed point. The
fixed point is characterized by a lack of oscillations in the eccentricities
and apsidal alignment among the orbits. Quantitatively, the nature of the fixed
point is dictated by mutual interactions among the planets as well as
non-Keplerian effects. We show that if a roughly coplanar system hosts a hot,
sub-Saturn mass planet, and is tidally relaxed, separation of planet-planet
interactions and non-Keplerian effects in the equations of motion leads to a
direct determination of the true masses of the planets. Consequently, a
"snap-shot" observational determination of the orbital state resolves the
sin(I) degeneracy, and opens up a direct avenue towards identification of the
true lowest-mass exo-planets detected. We present an approximate, as well as a
general, mathematical framework for computation of the line of sight
inclination of secular systems, and apply our models illustratively to the 61
Vir system. We conclude by discussing the observability of planetary systems to
which our method is applicable and we set our analysis into a broader context
by presenting a current summary of the various possibilities for determining
the physical properties of planets from observations of their orbital states.Comment: 9 pages, 7 figures, 1 table, Accepted to the Astrophysical Journa
Effective potential in three-dimensional O(N) models
We consider the effective potential in three-dimensional models with O(N)
symmetry. For generic values of N, and in particular for the physically
interesting cases N=0,1,2,3, we determine the six-point and eight-point
renormalized coupling constants which parametrize its small-field expansion.
These estimates are obtained from the analysis of their -expansion,
taking into account the exact results in one and zero dimensions, and, for the
Ising model (i.e. N=1), the accurate high-temperature estimates in two
dimensions. They are compared with the available results from other approaches.
We also obtain corresponding estimates for the two-dimensional O() models.Comment: 22 pages, revtex, 2 fig
The Complex Structure of the Multi-Phase Galactic Wind in a Starburst Merger
Neutral outflows have been detected in many ultraluminous infrared galaxies
(ULIRGs) via the Na I D absorption-line doublet.
For the first time, we have mapped and analyzed the 2-D kinematics of a cool
neutral outflow in a ULIRG, F10565+2448, using the integral field unit (IFU) on
Gemini North to observe the Na I D feature. At the same time we have mapped the
ionized outflow with the [NII] and H emission lines. We find a systemic
rotation curve that is consistent with the rotation of the molecular disk
determined from previous CO observations. The absorption lines show evidence of
a nuclear outflow with a radial extent of at least 3 kpc, consistent with
previous observations. The strength of the Na I D lines have a strong,
spatially resolved correlation with reddening, suggesting that dust is present
in the outflow. Surprisingly, the outflow velocities of the neutral gas show a
strong asymmetry in the form of a major-axis gradient that is opposite in sign
to disk rotation. This is inconsistent with entrained material rotating along
with the galaxy or with a tilted minor-axis outflow. We hypothesize that this
unusual behavior is due to an asymmetry in the distribution of the ambient gas.
We also see evidence of asymmetric ionized outflow in the emission-line
velocity map, which appear to be decoupled from the neutral outflow. Our
results strengthen the hypothesis that ULIRG outflows differ in morphology from
those in more quiescent disk galaxies.Comment: Accepted to Ap
Moving glass phase of driven lattices
We study periodic lattices, such as vortex lattices, driven by an external
force in a random pinning potential. We show that effects of static disorder
persist even at large velocity. It results in a novel moving glass state with
topological order analogous to the static Bragg glass. The lattice flows
through well-defined, elastically coupled, {\it % static} channels. We predict
barriers to transverse motion resulting in finite transverse critical current.
Experimental tests of the theory are proposed.Comment: Revised version, shortened, 8 pages, REVTeX, no figure
Characterization of hexabundles: Initial results
New multi-core imaging fibre bundles -- hexabundles -- being developed at the
University of Sydney will provide simultaneous integral field spectroscopy for
hundreds of celestial sources across a wide angular field. These are a natural
progression from the use of single fibres in existing galaxy surveys.
Hexabundles will allow us to address fundamental questions in astronomy without
the biases introduced by a fixed entrance aperture. We have begun to consider
instrument concepts that exploit hundreds of hexabundles over the widest
possible field of view. To this end, we have compared the performance of a
61-core fully-fused hexabundle and 5 lightly-fused bundles with 7 cores each.
All fibres in the bundles have 100 micron cores. In the fully-fused bundle, the
cores are distorted from a circular shape in order to achieve a higher fill
fraction. The lightly-fused bundles have circular cores and five different
cladding thicknesses which affect the fill fraction. We compare the optical
performance of all 6 bundles and find that the advantage of smaller
interstitial holes (higher fill fraction) is outweighed by the increase in
modal coupling, cross-talk and the poor optical performance caused by the
deformation of the fibre cores. Uniformly high throughput and low cross-talk
are essential for imaging faint astronomical targets with sufficient resolution
to disentangle the dynamical structure. Devices already under development will
have between 100 and 200 lightly-fused cores, although larger formats are
feasible. The light-weight packaging of hexabundles is sufficiently flexible to
allow existing robotic positioners to make use of them.Comment: Accepted for publication in MNRAS. See also a complimentary paper on
the development of hexabundles - Bland-Hawthorn et al. 2011, Optics Express,
vol. 19, p. 2649
(http://www.opticsinfobase.org/abstract.cfm?URI=oe-19-3-2649
Verbal labels selectively bias brain responses to high-energy foods.
The influence of external factors on food preferences and choices is poorly understood. Knowing which and how food-external cues impact the sensory processing and cognitive valuation of food would provide a strong benefit toward a more integrative understanding of food intake behavior and potential means of interfering with deviant eating patterns to avoid detrimental health consequences for individuals in the long run. We investigated whether written labels with positive and negative (as opposed to 'neutral') valence differentially modulate the spatio-temporal brain dynamics in response to the subsequent viewing of high- and low-energetic food images. Electrical neuroimaging analyses were applied to visual evoked potentials (VEPs) from 20 normal-weight participants. VEPs and source estimations in response to high- and low- energy foods were differentially affected by the valence of preceding word labels over the ~260-300 ms post-stimulus period. These effects were only observed when high-energy foods were preceded by labels with positive valence. Neural sources in occipital as well as posterior, frontal, insular and cingulate regions were down-regulated. These findings favor cognitive-affective influences especially on the visual responses to high-energetic food cues, potentially indicating decreases in cognitive control and goal-adaptive behavior. Inverse correlations between insular activity and effectiveness in food classification further indicate that this down-regulation directly impacts food-related behavior
Generating Controlled Image Sets in Cognitive Neuroscience Research
The investigation of perceptual and cognitive functions with non-invasive brain imaging methods critically depends on the careful selection of stimuli for use in experiments. For example, it must be verified that any observed effects follow from the parameter of interest (e.g. semantic category) rather than other low-level physical features (e.g. luminance, or spectral properties). Otherwise, interpretation of results is confounded. Often, researchers circumvent this issue by including additional control conditions or tasks, both of which are flawed and also prolong experiments. Here, we present some new approaches for controlling classes of stimuli intended for use in cognitive neuroscience, however these methods can be readily extrapolated to other applications and stimulus modalities. Our approach is comprised of two levels. The first level aims at equalizing individual stimuli in terms of their mean luminance. Each data point in the stimulus is adjusted to a standardized value based on a standard value across the stimulus battery. The second level analyzes two populations of stimuli along their spectral properties (i.e. spatial frequency) using a dissimilarity metric that equals the root mean square of the distance between two populations of objects as a function of spatial frequency along x- and y-dimensions of the image. Randomized permutations are used to obtain a minimal value between the populations to minimize, in a completely data-driven manner, the spectral differences between image sets. While another paper in this issue applies these methods in the case of acoustic stimuli (Aeschlimann etal., Brain Topogr 2008), we illustrate this approach here in detail for complex visual stimul
Rice seed varietal purity inspection using hyperspectral imaging
When distributing rice seed to farmers, suppliers strive to ensure that all seeds delivered belong to the species that was ordered and that the batch is not contaminated by unhealthy seeds or seeds of a different species. A conventional method to inspect the varietal purity of rice seeds is based on manually selecting random samples of rice seed from a batch and evaluating the physical grain properties through a process of human visual inspection. This is a tedious, laborious, time consuming and extremely inefficient task where only a very small subset of the entire batch of the rice seed can be examined. There is, therefore, a need to automate this process to make it repeatable and more efficient while allowing a larger sample of rice seeds from any batch to be analysed. This paper presents an automatic rice seed inspection method which combines hyperspectral imaging and tools from machine learning to automatically detect seeds which are erroneously contained within a batch when they actually belong to a completely different species. Image data from Near-infrared (NIR) and Visible Light (VIS) hyperspectral cameras are acquired for six common rice seed varieties. Two different classifiers are applied to the data: a Support Vector Machine (SVM) and a Random Forest (RF), where each consists of six one-versus-rest binary classifiers. The results show that combining spectral and shape-based features derived from the rice seeds results in an increase in the precision (PPV) of the multi-label classification to 84% compared with 74% when only visual features are used
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