Semantic Approaches to Global Computing Systems

Daniele Gorla

PhD Thesis XVII-04-I in Informatica e Applicazioni, Univ. di Firenze, 2004.


Programming computational infrastructures available globally for offering uniform services has become one of the main issues in Computer Science. The challenges come from the variable guarantees for communication, co-operation and mobility, resource usage, security policies and mechanisms, etc. that have to be taken into account. A key issue is the definition of innovative theories, computational paradigms, linguistic mechanisms and implementation techniques for the design, realisation, deployment and management of global computational environments and their application.
A successful contribution to this research line is KLAIM, an experimental language with primitives for programming global computers that combines the process algebra approach with the coordination-oriented one. Its main features are process distribution and mobility, remote operations and asynchronous communication via multiple distributed tuple spaces. KLAIM has proved to be suitable for programming a wide range of distributed applications with agents and code mobility, and has been implemented on the top of a runtime system written in Java.
In this thesis, we first presents some foundational calculi for mobility based on KLAIM. Then, we concentrate on one of these calculi, namely muKLAIM, that retains most of the peculiar features of KLAIM, while being much simpler. We present two approaches to study the behaviours of global computing systems expressed in muKLAIM: (non-standard) type systems and behavioural equivalences. Type systems permit to control resource accesses, as well as data and process movements. Behavioural equivalences, on the other hand, permit to state and verify properties of distributed applications. Finally, we focus on the expressive power of the calculi by providing encodings of each calculus into a simpler one. The overall expressiveness is then assessed via a formal comparison with the asynchronous pi-calculus.

  author       = {Daniele Gorla},
  title        = {Semantic Approaches to Global Computing Systems},
  school       = {Dip. Sistemi ed Informatica, Univ. di Firenze},
  number       = {{XVII-04-I}},
  year         = {2004},

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