BIOSTIRLING-4SKA : A cost effective and efficient approach for a new generation of solar dish-Stirling plants based on storage and hybridization; An Energy demo project for Large Scale Infrastructures", [IMA]

The BIOSTIRLING – 4SKA (B4S) is a EU demonstration project dealing with the implementation of a cost-effective and efficient new generation of solar dish-Stirling plants based on hybridization and efficient storage at the industrial scale. The main goal of the B4S demonstration project is the generation of electric power using simultaneously solar power and gas to supply an isolated system and act as a scalable example of potential power supply for many infrastructures, including future sustainable large scientific infrastructures. B4S build an interdisciplinary approach to address reliability, maintainability and costs of this technology. In April 2017, B4S successfully tested in Portugal the first world Stirling hybrid system providing about 4kW of power to a phased array of antennas, overcoming challenges in Stirling and hybridization and smartgrid technologies. B4SKA Consortium, with fourteen companies from six European countries, has performed the engineering, construction, assembly and experimental exploitation, under contract signed with the European to develop on off-grid demonstrator in Contenda (Moura) Portugal.

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D. Barbosa, P. Andre, T. Paixao, et. al.
Mon, 11 Dec 17

Comments: 7 pages; 8 Figures; Proceedings of the 7th International Workshop on Integration of Solar Power into Power Systems, 2C_5_SIW17_299, Ed. Uta Betancourt, Thomas Ackermann, Berlin, Germany, 24-25th October 2017

A method of immediate detection of objects with a near-zero apparent motion in series of CCD-frames [IMA]

The paper deals with a computational method for detection of the solar system minor bodies (SSOs), whose inter-frame shifts in series of CCD-frames during the observation are commensurate with the errors in measuring their positions. These objects have velocities of apparent motion between CCD-frames not exceeding three RMS errors ($3\sigma$) of measurements of their positions. About 15\% of objects have a near-zero apparent motion in CCD-frames, including the objects beyond the Jupiter’s orbit as well as the asteroids heading straight to the Earth.
The proposed method for detection of the object’s near-zero apparent motion in series of CCD-frames is based on the Fisher f-criterion instead of using the traditional decision rules that are based on the maximum likelihood criterion. We analyzed the quality indicators of detection of the object’s near-zero apparent motion applying statistical and in situ modeling techniques in terms of the conditional probability of the true detection of objects with a near-zero apparent motion.
The efficiency of method being implemented as a plugin for the Collection Light Technology (CoLiTec) software for automated asteroids and comets detection has been demonstrated. Among the objects discovered with this plugin, there was the sungrazing comet C/2012 S1 (ISON). Within 26 minutes of the observation, the comet’s image has been moved by three pixels in a series of four CCD-frames (the velocity of its apparent motion at the moment of discovery was equal to 0.8 pixels per CCD-frame; the image size on the frame was about five pixels). Next verification in observations of asteroids with a near-zero apparent motion conducted with small telescopes has confirmed an efficiency of the method even in bad conditions (strong backlight from the full Moon). So, we recommend applying the proposed method for series of observations with four or more frames.

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V. Savanevych, S. Khlamov, I. Vavilova, et. al.
Fri, 8 Dec 17

Comments: 11 pages, 8 figures, 3 tables (accepted to A&A). The CoLiTec software is available on this http URL

Software metadata: How much is enough? [IMA]

Broad efforts are underway to capture metadata about research software and retain it across services; notable in this regard is the CodeMeta project. What metadata are important to have about (research) software? What metadata are useful for searching for codes? What would you like to learn about astronomy software? This BoF sought to gather information on metadata most desired by researchers and users of astro software and others interested in registering, indexing, capturing, and doing research on this software. Information from this BoF could conceivably result in changes to the Astrophysics Source Code Library (ASCL) or other resources for the benefit of the community or provide input into other projects concerned with software metadata.

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A. Allen, P. Teuben, G. Berriman, et. al.
Fri, 8 Dec 17

Comments: 4 pages; to be published in ADASS XXVII (held Oct 22-26, 2017 in Santiago, Chile) proceedings

Corner singularity and its application in regular parameters optimization: technique renovation for Grad-Shafranov reconstruction [IMA]

Further studies on the corner singularity of GS reconstruction are are compiled in this paper. It’s focused on solution of the Data Completion (DC) problem with the Extended Hilbert Transform (EHT) over plane rectangular region. Optimal selections of the regular parameters in{\it Tikhonov} solution of corresponding DC problem are developed in this study. The 6-parameter regular solutions and the {\it Jacobian} matrix and one {\it Hessian} tensor to the regular parameters are derived in this work. A concise formula for EHT in the near field of corners, which shows property for EHT near the corner, are also provided. It serves as the additional constraints for our parameter optimization problem (OP). Third, a nonlinear convex function defined by the regular solution and the corner constraints is introduced and is taken as the object function for the OP of the 6 regular parameters on half-space $(\mathbf{p}>0)$. Given an initial guess of $\mathbf{p}_0$, the optimal parameters are solved from the OP through a well known constrained nonlinear optimization method. Last, the benchmark tests to the proposed solution approach are carried out, and detailed results from totally 9 different bench-cases are tabulated. In contrast to solutions with given regular parameters, our bench results demonstrate that an objective way for selection of the optimal $\mathbf{p}$ is successfully laid out here. Robustness and efficiency of the suggested new approach are also highlighted in this study.

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H. LI, C. Li, X. Feng, et. al.
Fri, 8 Dec 17

Comments: 7 pages, 3 figures, and 2 tables

Interoperable geographically distributed astronomical infrastructures: technical solutions [IMA]

The increase of astronomical data produced by a new generation of observational tools poses the need to distribute data and to bring computation close to the data. Trying to answer this need, we set up a federated data and computing infrastructure involving an international cloud facility, EGI federated, and a set of services implementing IVOA standards and recommendations for authentication, data sharing and resource access. In this paper we describe technical problems faced, specifically we show the designing, technological and architectural solutions adopted. We depict our technological overall solution to bring data close to computation resources. Besides the adopted solutions, we propose some points for an open discussion on authentication and authorization mechanisms.

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S. Bertocco, B. Major, P. Dowler, et. al.
Fri, 8 Dec 17

Comments: 4 pages, 1 figure, submitted to Astronomical Society of the Pacific (ASP)

Deep learning Approach for Classifying, Detecting and Predicting Photometric Redshifts of Quasars in the Sloan Digital Sky Survey Stripe 82 [IMA]

We apply a convolutional neural network (CNN) to classify and detect quasars in the Sloan Digital Sky Survey Stripe 82 and also to predict the photometric redshifts of quasars. The network takes the variability of objects into account by converting light curves into images. The width of the images, noted w, corresponds to the five magnitudes ugriz and the height of the images, noted h, represents the date of the observation. The CNN provides good results since its precision is 0.988 for a recall of 0.90, compared to a precision of 0.985 for the same recall with a random forest classifier. Moreover 175 new quasar candidates are found with the CNN considering a fixed recall of 0.97. The combination of probabilities given by the CNN and the random forest makes good performance even better with a precision of 0.99 for a recall of 0.90.
For the redshift predictions, the CNN presents excellent results which are higher than those obtained with a feature extraction step and different classifiers (a K-nearest-neighbors, a support vector machine, a random forest and a gaussian process classifier). Indeed, the accuracy of the CNN within |\Delta z|<0.1 can reach 78.09%, within |\Delta z|<0.2 reaches 86.15%, within |\Delta z|<0.3 reaches 91.2% and the value of rms is 0.359. The performance of the KNN decreases for the three |\Delta z| regions, since within the accuracy of |\Delta z|<0.1, |\Delta z|<0.2 and |\Delta z|<0.3 is 73.72%, 82.46% and 90.09% respectively, and the value of rms amounts to 0.395. So the CNN successfully reduces the dispersion and the catastrophic redshifts of quasars. This new method is very promising for the future of big databases like the Large Synoptic Survey Telescope.

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J. Pasquet-Itam and J. Pasquet
Fri, 8 Dec 17

Comments: N/A

Building an interoperable, distributed storage and authorization system [IMA]

A joint project between the Canadian Astronomy Data Center of the National Research Council Canada, and the italian Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Trieste (INAF-OATs), partially funded by the EGI-Engage H2020 European Project, is devoted to deploy an integrated infrastructure, based on the International Virtual Observatory Alliance (IVOA) standards, to access and exploit astronomical data. Currently CADC-CANFAR provides scientists with an access, storage and computation facility, based on software libraries implementing a set of standards developed by the International Virtual Observatory Alliance (IVOA). The deployment of a twin infrastructure, basically built on the same open source software libraries, has been started at INAF-OATs. This new infrastructure now provides users with an Access Control Service and a Storage Service. The final goal of the ongoing project is to build an integrated infrastructure geographycally distributed providing complete interoperability, both in users access control and data sharing. This paper describes the target infrastructure, the main user requirements covered, the technical choices and the implemented solutions.

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S. Bertocco, B. Major, P. Dowler, et. al.
Fri, 8 Dec 17

Comments: 4 pages, 2 figures, submitted to Astronomical Society of the Pacific (ASP) as part of their Conference Series