Workflow level interoperation of grid data resources

The lack of widely accepted standards and the use of different middleware solutions divide today’s Grid resources into non-interoperable production Grid islands. On the other hand, more and more experiments require such a large number of resources that the interoperation of existing production Grids becomes inevitable. This paper, based on the current results of grid interoperation studies, defines generic requirements towards the workflow level interoperation of grid solutions. It concentrates on intra-workflow interoperation of grid data resources, as one of the key areas of generic interoperation, and describes through an example how existing tools can be extended to achieve the required level of interoperation

Service-oriented production grids and user support

Currently several production Grids offer their resources for academic communities. These Grids are resource-oriented Grids with minimal user support. The existing user support incorporates Grid portals without workflow editing and execution capabilities, brokering with no QoS and SLA management, security solutions without privacy and trust management, etc. They do not provide any kind of support for running legacy code applications on Grids. Production Grids started the migration from resource-oriented Grids to service-oriented ones. The migration defines additional requirements towards the user support. These requirements include solving interoperability among Grids, automatic service deployment, dynamic user management, legacy code support, QoA and SLA-based brokering, etc. This paper discusses some aspects of the user support needed for service-oriented production Grids

MiCADO – Towards a Microservice-based Cloud Application-level Dynamic Orchestrator

In order to satisfy end-user requirements, many scientific and commercial applications require access to dynamically adjustable infrastructure resources. Cloud computing has the potential to provide these dynamic capabilities. However, utilising these capabilities from application code is not trivial and requires application developers to understand low-level technical details of clouds. This paper investigates how a generic framework can be developed that supports the dynamic orchestration of cloud applications both at deployment and at run-time. The advantages and challenges of designing such framework based on microservices is analysed, and a generic framework, called MiCADO – (Microservices-based Cloud Application-level Dynamic Orchestrator) is proposed. A first prototype implementation of MiCADO to support data intensive commercial web applications is also presented

The StarScan plate measuring machine: overview and calibrations

The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 micrometer. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x,y data is derived to be 0.5 micrometer. Application to real photographic plate data shows that position information of at least 0.65 micrometer accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "reverse" measures of fine grain emulsion plate measures are obtained on the 0.3 micrometer level per well exposed stellar image and coordinate, which is at the limit of the StarScan machine.Comment: 24 pages, 8 figures, accepted for PAS

On the stability around Chariklo and the confinement of its rings

Chariklo has two narrow and dense rings, C1R and C2R, located at 391 km and 405 km, respectively. In the light of new stellar occultation data, we study the stability around Chariklo. We also analyse three confinement mechanisms, to prevent the spreading of the rings, based on shepherd satellites in resonance with the edges of the rings. This study is made through a set of numerical simulations and the Poincar\'e surface of section technique. From the numerical simulation results we verify that, from the current parameters referring to the shape of Chariklo, the inner edge of the stable region is much closer to Chariklo than the rings. The Poincar\'e surface of sections allow us to identify the first kind periodic and quasi-periodic orbits, and also the resonant islands corresponding to the 1:2, 2:5, and 1:3 resonances. We construct a map of a versus e space which gives the location and width of the stable region and the 1:2, 2:5, and 1:3 resonances. We found that the first kind periodic orbits family can be responsible for a stable region whose location and size meet that of C1R, for specific values of the ring particles' eccentricities. However, C2R is located in an unstable region if the width of the ring is assumed to be about 120 m. After analysing different systems we propose that the best confinement mechanism is composed of three satellites, two of them shepherding the inner edge of C1R and the outer edge of C2R, while the third satellite would be trapped in the 1:3 resonance.Comment: Accepted for publication in Astronomy & Astrophysic