Specification and Verification of
Component-Based Systems
Workshop at
November 9-10, 2008

Professor Wolfgang Emmerich from London Software Systems and University College London will give an invited talk on "Verification Challenges for Components in Federated Distributed Systems".


A federated distributed system consists of components that interact across organisational boundaries. Examples of such systems include those that use web services to invoke components of another organisation, peer-to-peer systems or cloud computing infrastructures. The component interaction in such systems is frequently achieved using the public Internet, which itself is a federation of autonomous network service providers. The autonomy of both hosting organizations and network service providers has a number of consequences for building dependable distributed systems and in this talk we will discuss particularly those that affect specification and verification.

Firstly, many specification and verification approaches assume that dependability constraints are to be met at any cost. This is generally not the case in federated systems because economic constraints may force an organization to reduce the dependability of its service provision.

For example IP routing protocols routinely drop packets instead of forwarding them if routes are congested with higher value packets, or transport protocols lower transmission rates to reduce congestion.

Secondly, verification techniques for components generally make closed-world assumptions, meaning that the behaviour of a component and assumptions about its environment are fully known. Again this does not generally hold in federated distributed systems because autonomous organizations might unilaterally invalidate assumptions that held previously. We conclude the talk by sketching specification and verification techniques that can cope with autonomy in federated systems.

Biographical Sketch

Wolfgang obtained his PhD in the Dept. of Mathematics and Computer Science at the University of Paderborn. Following a Visiting Scholarship at the Software Verification Research Centre at the University of Queensland in Brisbane, Australia he joined The City University in London as a Lecturer. In 1997, Wolfgang joined University College London, where he now holds a Chair in Distributed Computing in the Department of Computer Science. At UCL, Wolfgang is also Deputy Head of Department and Director of Research. Wolfgang is a member of the Editorial Board of the IEEE Transactions on Computer Science and was PC Co-Chair of the Int. Conf. on Software Engineering in 2007. Wolfgang's research interest are in the area of software engineering techniques for large scale, distributed systems. He is a member of the ACM, the IEEE Computer Society, the IET. Wolfgang is Chartered Engineer. Wolfgang also is co-founder of a number of start-up companies, the most significant of which is the Zuhlke Technology Group, which currently employs 325 members of staff in seven offices in Western Europe.