Publications in Monitoring

Articles in Refereed Journals:

1. L. Baresi, D. Bianculli, C. Ghezzi, S. Guinea, P. Spoletini. Validation of web service compositions. IET Software, Vol. 1, Num. 6, pages 219-232, December 2007.
   Abstract: Web services support software architectures that can evolve dynamically. In particular, in this paper the focus is on architectures where services are composed (orchestrated) through a workflow described in the business process execution language (BPEL). It is assumed that the resulting composite service refers to external services through assertions that specify their expected functional and non-functional properties. On the basis of these assertions, the composite service may be verified at design time by checking that it ensures certain relevant properties. Because of the dynamic nature of web services and the multiple stakeholders involved in their provision, however, the external services may evolve dynamically, and even unexpectedly. They may become inconsistent with respect to the assertions against which the workflow was verified during development. As a consequence, validation of the composition must extend to run time. In this work, an assertion language, called assertion language for BPEL process interactions (ALBERT), is introduced; it can be used to specify both functional and non-functional properties. An environment which supports design-time verification of ALBERT assertions for BPEL workflows via model checking is also described. At run time, the assertions can be turned into checks that a software monitor performs on the composite system to verify that it continues to guarantee its required properties. A TeleAssistance application is provided as a running example to illustrate our validation framework.

2. Andrew W. Cooke, Alasdair J. G. Gray, Werner Nutt, James Magowan, Manfred Oevers, Paul Taylor, Roney Cordenonsi, Rob Byrom, Linda Cornwall, Abdeslem Djaoui, Laurence Field, Steve Fisher, Steve Hicks, Jason Leake, Robin Middleton, Antony J. Wilson, Xiaomei Zhu, Norbert Podhorszki, Brian A. Coghlan, Stuart Kenny, David O'Callaghan, John Ryan. The Relational Grid Monitoring Architecture: Mediating Information about the Grid. J. Grid Comput., Vol. 2, Num. 4, pages 323-339, 2004.
   Abstract: We have developed and implemented the Relational Grid Monitoring Architecture (R-GMA) as part of the DataGrid project, to provide a flexible information and monitoring service for use by other middleware components and applications. R-GMA presents users with a virtual database and mediates queries posed at this database: users pose queries against a global schema and R-GMA takes responsibility for locating relevant sources and returning an answer. R-GMAs architecture and mechanisms are general and can be used wherever there is a need for publishing and querying information in a distributed environment. We discuss the requirements, design and implementation of R-GMA as deployed on the DataGrid testbed. We also describe some of the ways in which R-GMA is being used.

Articles in Refereed Conferences:

1. Fabio Barbon, Paolo Traverso, Marco Pistore, Michele Trainotti. Run-Time Monitoring of Instances and Classes of Web Service Compositions. ICWS, pages 63-71, 2006.
   Abstract: The run-time monitoring of web service compositions has been widely acknowledged as a significant and challenging problem. In this paper, we propose a novel solution to the problem of monitoring web services implemented in BPEL. We devise an architecture that clearly separates the business logic of a web service from its monitoring functionality. The architecture supports both "instance monitors" that deal with the execution of a single instance of BPEL process, as well as "class monitors" that report aggregated information about all the instances of a BPEL process. We also define a language for the specification of instance and class monitors. The language allows for specifying boolean, statistic, and time-related properties. Finally, we devise a technique for the automatic translation of all these kinds of monitors to Java programs.

2. Luciano Baresi, Sam Guinea. Towards Dynamic Monitoring of WS-BPEL Processes. ICSOC, pages 269-282, 2005.
   Abstract: The intrinsic flexibility and dynamism of service-centric applications preclude their pre-release validation and demand for suitable probes to monitor their behavior at run-time. Probes must be suitably activated and deactivated according to the context in which the application is executed, but also according to the confidence we get on its quality. The paper supports the idea that significant data may come from very different sources and probes must be able to accommodate all of them. The paper presents: (1) an approach to specify monitoring directives, called monitoring rules, and weave them dynamically into the process they belong to; (2) a proxy-based solution to support the dynamic selection and execution of monitoring rules at run-time; (3) a user-oriented language to integrate data acquisition and analysis into monitoring rules.

3. Khaled Mahbub, George Spanoudakis. Run-time Monitoring of Requirements for Systems Composed of Web-Services: Initial Implementation and Evaluation Experience. ICWS, pages 257-265, 2005.
   Abstract: This paper describes a framework supporting the runtime monitoring of requirements for systems implemented as compositions of Web-services specified in BPEL. The requirements that can be monitored are specified in event calculus. The paper presents an overview of the framework and describes the architecture and implementation of a tool that we have developed to operationalise it. It also presents the results of a preliminary experimental evaluation of the framework.