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The ALMA Observation Support Tool (OST) is an ALMA simulator which is interacted with solely via a standard web browser. It is aimed at users who may or may not be experts in interferometry, or those that do not wish to familarise themselves with the simulation components of a data reduction package. It has been designed to offer full imaging simulation capability for an arbitrary ALMA observation while maintaining the accessibility of other online tools such as the ALMA Sensitivity Calculator. Simulation jobs are defined by selecting and entering options on a standard web form. The user can specify the standard parameters that would need to be considered for an ALMA observation (e.g. pointing direction, frequency set up, duration), and there is also the option to upload arbitrary sky models in FITS format. Once submitted, jobs are sequentially processed by a remote server running a CASA-based back-end system. The user is notified by email when the job is complete, and directed to a standard web page which contains the results of the simulation and a range of downloadable data products. The system is currently hosted by the UK ALMA Regional Centre, and can be accessed by directing a web browser to http://almaost.jb.man.ac.uk.
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In recent years there has been a paradigm shift from centralised to geographically distributed resources. Individual entities are no longer able to host or afford the necessary expertise in-house, and, as a consequence, society increasingly relies on widespread collaborations. Although such collaborations are now the norm for scientific projects, more technical structures providing support to a distributed scientific community without direct financial or other material benefits are scarce. The network of European ALMA Regional Centre (ARC) nodes is an example of such an internationally distributed user support network. It is an organised effort to provide the European ALMA user community with uniform expert support to enable optimal usage and scientific output of the ALMA facility. The network model for the European ARC nodes is described in terms of its organisation, communication strategies and user support.
While the Atacama Large Millimeter/submillimeter Array (ALMA) is a uniquely powerful telescope, its impact in certain fields of astrophysics has been limited by observatory policies rather than the telescopes innate technical capabilities. In particular, several observatory policies present challenges for observations of variable, mobile, and/or transient sources --- collectively referred to here as time-domain observations. In this whitepaper we identify some of these policies, describe the scientific applications they impair, and suggest changes that would increase ALMAs science impact in Cycle 6 and beyond. Parties interested in time-domain science with ALMA are encouraged to join the ALMA Time-domain Special Interest Group (ATSIG) by signing up for the ATSIG mailing list at https://groups.google.com/group/alma-td-sig .
Astronomical observation data require long-term preservation, and the rapid accumulation of observation data makes it necessary to consider the cost of long-term archive storage. In addition to low-speed disk-based online storage, optical disk or tape-based offline storage can be used to save costs. However, for astronomical research that requires historical data (particularly time-domain astronomy), the performance and energy consumption of data-accessing techniques cause problems because the requested data (which are organized according to observation time) may be located across multiple storage devices. In this study, we design and develop a tool referred to as AstroLayout to redistribute the observation data using spatial aggregation. The core algorithm uses graph partitioning to generate an optimized data placement according to the original observation data statistics and the target storage system. For the given observation data, AstroLayout can copy the long-term archive in the target storage system in accordance with this placement. An efficiency evaluation shows that AstroLayout can reduce the number of devices activated when responding to data-access requests in time-domain astronomy research. In addition to improving the performance of data-accessing techniques, AstroLayout can also reduce the storage systems power consumption. For enhanced adaptability, it supports storage systems of any media, including optical disks, tapes, and hard disks.
Many different tagsets are used in existing corpora; these tagsets vary according to the objectives of specific projects (which may be as far apart as robust parsing vs. spelling correction). In many situations, however, one would like to have uniform access to the linguistic information encoded in corpus annotations without having to know the classification schemes in detail. This paper describes a tool which maps unstructured morphosyntactic tags to a constraint-based, typed, configurable specification language, a ``standard tagset. The mapping relies on a manually written set of mapping rules, which is automatically checked for consistency. In certain cases, unsharp mappings are unavoidable, and noise, i.e. groups of word forms {sl not} conforming to the specification, will appear in the output of the mapping. The system automatically detects such noise and informs the user about it. The tool has been tested with rules for the UPenn tagset cite{up} and the SUSANNE tagset cite{garside}, in the framework of the EAGLESfootnote{LRE project EAGLES, cf. cite{eagles}.} validation phase for standardised tagsets for European languages.
Up to now, the completion of an ALMA interferometric observation is determined based on the achievement of a given shape and size of the synthesized beam and the noise RMS in the representative spectral range. This approach with respect to the angular resolution investigates mainly the longest baselines of the interferometer and says little about the sensitivity at larger angular scales. We are exploring the ideas of angular-scale-based scheduling and quality assessment, and of angular-scale-based visibility weighting as a step towards optimising both observation efficiency and image fidelity. This approach carries the imaging quality assurance into the visibility space where interferometers record the data, and therefore simplifies many aspects of the procedure. Similarly, during scheduling such detailed assessment of the expected imaging properties helps optimising the scheduling process. The methodology is applicable to all radio interferometers with more than ca. 10 antennas.
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