15,565 research outputs found

    The Millennium Run Observatory: First Light

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    Simulations of galaxy evolution aim to capture our current understanding as well as to make predictions for testing by future experiments. Simulations and observations are often compared in an indirect fashion: physical quantities are estimated from the data and compared to models. However, many applications can benefit from a more direct approach, where the observing process is also simulated and the models are seen fully from the observer's perspective. To facilitate this, we have developed the Millennium Run Observatory (MRObs), a theoretical virtual observatory which uses virtual telescopes to `observe' semi-analytic galaxy formation models based on the suite of Millennium Run dark matter simulations. The MRObs produces data that can be processed and analyzed using the standard software packages developed for real observations. At present, we produce images in forty filters from the rest-frame UV to IR for two stellar population synthesis models, three different models of IGM absorption, and two cosmologies (WMAP1/7). Galaxy distributions for a large number of mock lightcones can be `observed' using models of major ground- and space-based telescopes. The data include lightcone catalogues linked to structural properties of galaxies, pre-observation model images, mock telescope images, and Source Extractor products that can all be traced back to the higher level dark matter, semi-analytic galaxy, and lightcone catalogues available in the Millennium database. Here, we describe our methods and announce a first public release of simulated surveys (e.g., SDSS, CFHT-LS, GOODS, GOODS/ERS, CANDELS, and HUDF). The MRObs browser, an online tool, further facilitates exploration of the simulated data. We demonstrate the benefits of a direct approach through a number of example applications (galaxy number counts in CANDELS, clusters, morphologies, and dropout selections).Comment: MNRAS, in press. Millennium Run Observatory data products, online tools, and more available through http://galformod.mpa-garching.mpg.de/mrobs

    A Building Stone Assessment of sandstone in Iona Nunnery and at Carsaig quarry on Mull

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    This report presents the outcomes of a project commissioned by Historic Scotland to determine, using a combination of archival records and geological evidence, whether blocks of sandstone in Iona Nunnery (a Scheduled Monument on the island of Iona) came from Carsaig quarry (a long-disused quarry on the south coast of Mull). The report also considers the feasibility of sourcing new stone to use in future repairs to the nunnery from Carsaig quarry and from the remains of nearby Carsaig pier. Details of the most suitable commercially available stones from elsewhere in the UK are also provided, should it prove not possible or not practical to obtain new stone from Carsaig quarry or Carsaig pier

    Evolution and Fragility of Mobile Automated Test Suites

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    L'abstract Ăš presente nell'allegato / the abstract is in the attachmen

    Carbon stars in the X-shooter Spectral Library

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    We provide a new collection of spectra of 35 carbon stars obtained with the ESO/VLT X-shooter instrument as part of the X-shooter Spectral Library project. The spectra extend from 0.3ÎŒ\mum to 2.4ÎŒ\mum with a resolving power above ∌\sim 8000. The sample contains stars with a broad range of (J-K) color and pulsation properties located in the Milky Way and the Magellanic Clouds. We show that the distribution of spectral properties of carbon stars at a given (J-K) color becomes bimodal (in our sample) when (J-K) is larger than about 1.5. We describe the two families of spectra that emerge, characterized by the presence or absence of the absorption feature at 1.53ÎŒ\mum, generally associated with HCN and C2_2H2_2. This feature appears essentially only in large-amplitude variables, though not in all observations. Associated spectral signatures that we interpret as the result of veiling by circumstellar matter, indicate that the 1.53ÎŒ\mum feature might point to episodes of dust production in carbon-rich Miras.Comment: 29 pages, 21 figures, 9 tables, Accepted for publication in A&

    String theory: an update

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    An overview of some of the developments in string theory over the past two years is given, focusing on four topics: realistic (standard model like) models from string theory, geometric engineering and theories with fluxes, the gauge theory-gravity correspondence, and time dependent backgrounds and string theory. Plenary talk at ICHEP'02, Amsterdam, July 24-31, 2002.Comment: 20 pages, 2 figures, uses espcrc2.sty, v2: several references added, apologies for the delay in submitting this updated versio

    Simple identification tools in FishBase

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    Simple identification tools for fish species were included in the FishBase information system from its inception. Early tools made use of the relational model and characters like fin ray meristics. Soon pictures and drawings were added as a further help, similar to a field guide. Later came the computerization of existing dichotomous keys, again in combination with pictures and other information, and the ability to restrict possible species by country, area, or taxonomic group. Today, www.FishBase.org offers four different ways to identify species. This paper describes these tools with their advantages and disadvantages, and suggests various options for further development. It explores the possibility of a holistic and integrated computeraided strategy

    Examples of SAR-centric patent mining using open resources

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    Bag-Level Aggregation for Multiple Instance Active Learning in Instance Classification Problems

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    A growing number of applications, e.g. video surveillance and medical image analysis, require training recognition systems from large amounts of weakly annotated data while some targeted interactions with a domain expert are allowed to improve the training process. In such cases, active learning (AL) can reduce labeling costs for training a classifier by querying the expert to provide the labels of most informative instances. This paper focuses on AL methods for instance classification problems in multiple instance learning (MIL), where data is arranged into sets, called bags, that are weakly labeled. Most AL methods focus on single instance learning problems. These methods are not suitable for MIL problems because they cannot account for the bag structure of data. In this paper, new methods for bag-level aggregation of instance informativeness are proposed for multiple instance active learning (MIAL). The \textit{aggregated informativeness} method identifies the most informative instances based on classifier uncertainty, and queries bags incorporating the most information. The other proposed method, called \textit{cluster-based aggregative sampling}, clusters data hierarchically in the instance space. The informativeness of instances is assessed by considering bag labels, inferred instance labels, and the proportion of labels that remain to be discovered in clusters. Both proposed methods significantly outperform reference methods in extensive experiments using benchmark data from several application domains. Results indicate that using an appropriate strategy to address MIAL problems yields a significant reduction in the number of queries needed to achieve the same level of performance as single instance AL methods
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