Formal Specification and Testing of a Management Architecture

The importance of network and distributed systems management to supply and maintain services required by users has led to a demand for management facilities. Open network management is assisted by representing the system resources to be managed as objects, and providing standard services and protocols for interrogating and manipulating these objects. This paper examines the application of formal description techniques to the specification of managed objects by presenting a case study in the specification and testing of a management architecture. We describe a formal specification of a management architecture suitable for scheduling and distributing services across nodes in a distributed system. In addition, we show how formal specifications can be used to generate conformance tests for the management architecture

Foundations of Black Hole Accretion Disk Theory

This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).Comment: 91 pages, 23 figures, final published version available at http://www.livingreviews.org/lrr-2013-

Towards Correct Executable Semantics For Z

There are many ad hoc tools aimed at the animation of executable subsets of the formal specification language Z. This paper presents an approach to rigorously establishing the correctness of such Z animation tools, drawing on ideas from the field of abstract interpretation. Enough of the standard Zsyntax is treated to cover most uses of Z schemas and expressions, after schema calculus constructs have been expanded and embedded schema references replaced

The specification and testing of conformance in ODP systems

Open Distributed Processing (ODP) is a joint standardisation activity of the ISO and ITU. A reference model has been defined which describes an architecture for building open distributed systems. This paper introduces the key aspects of the reference model of open distributed processing, including the ODP conformance framework. We discuss how specific formal techniques are used in the ODP viewpoints, along with the implications for conformance assessment using such techniques. Particular attention is given to the role of consistency in the conformance assessment process. Finally, we review the current work on an ODP conformance testing methodology. Keywords: Open Distributed Processing; Conformance; Formal Description Techniques. 1 THE OPEN DISTRIBUTED PROCESSING MODEL Open Distributed Processing (ODP) [29] is a joint standardisation activity of the ISO and ITU. A reference model has been defined which describes an architecture for building open distributed systems [36, 33]. Central..