Now showing items 1-8 of 8

  • Analysing web-orchestrations under stress using uncertainty profiles 

    Gabarró Vallès, Joaquim; Serna Iglesias, María José; Stewart, Alan (Wiley Heyden, 2014-11-01)
    Article
    Open Access
    An orchestration is a multi-threaded computation that invokes a number of remote services. In practice, the responsiveness of a web-service fluctuates with demand; during surges in activity service responsiveness may be ...
  • Axiomatic frameworks for developing BSP-style programs 

    Stewart, Alan; Clint, M.; Gabarró Vallès, Joaquim (1999-04)
    External research report
    Open Access
    In BSP a superstep comprises a collection of concurrently executed processes with initial and terminal synchronisations. Data transfer between processes is realised through asynchronous communications. BSP programs can ...
  • Reasoning about orchestrations of web services using partial correctness 

    Stewart, Alan; Gabarró Vallès, Joaquim; Keenan, Anthony (2013-11-01)
    Article
    Restricted access - publisher's policy
    A service is a remote computational facility which is made available for general use by means of a wide-area network. Several types of service arise in practice: stateless services, shared state services and services with ...
  • Refinement by browsing: an alternative to thumbnails 

    Gabarró Vallès, Joaquim; Vallejo, Isabel; Xhafa Xhafa, Fatos; Stewart, Alan; Clint, Maurice (2005-03)
    External research report
    Open Access
    Thumbnails are widely used in image retrieval and browsing systems. The use of such images compacts information. However, in situations where there are a large number of images on a server site, the use of thumbnails may ...
  • Stressed web environments as strategic games: risk profiles and Weltanschauung 

    Gabarró Vallès, Joaquim; Kilpatrick, Peter; Serna Iglesias, María José; Stewart, Alan (Publicació Electrònica en CD-ROM, 2010)
    Conference report
    Open Access
    We consider the behaviour of a set of services in a stressed web environment where performance patterns may be di cult to pre- dict. In stressed environments the performances of some providers may degrade while the ...
  • The robustness of periodic orchestrations in uncertain evolving environments 

    Castro Rabal, Jorge; Gabarró Vallès, Joaquim; Serna Iglesias, María José; Stewart, Alan (Springer, 2015)
    Conference report
    Open Access
    A framework for assessing the robustness of long-duration repetitive orchestrations in uncertain evolving environments is proposed. The model assumes that service-based evaluation environments are stable over short ...
  • Towards refining BSP programs into loosely coupled distributed systems 

    Stewart, Alan; Clint, M.; Gabarró Vallès, Joaquim; Serna Iglesias, María José (2001-03)
    External research report
    Open Access
    An experiment is conducted to assess the feasibility of transforming BSP computations into loosely coupled distributed systems employing asynchronous point-to-point communications. The BSP model bundles communications ...
  • Uncertainty in the cloud: an angel-daemon approach to modelling performance 

    Stewart, Alan; Gabarró Vallès, Joaquim; Keenan, Anthony (Springer, 2015)
    Conference report
    Open Access
    Uncertainty profiles are used to study the effects of contention within cloud and service-based environments. An uncertainty profile provides a qualitative description of an environment whose quality of service (QoS) may ...