A synchronous program algebra: a basis for reasoning about shared-memory and event-based concurrency

This research started with an algebra for reasoning about rely/guarantee concurrency for a shared memory model. The approach taken led to a more abstract algebra of atomic steps, in which atomic steps synchronise (rather than interleave) when composed in parallel. The algebra of rely/guarantee concurrency then becomes an instantiation of the more abstract algebra. Many of the core properties needed for rely/guarantee reasoning can be shown to hold in the abstract algebra where their proofs are simpler and hence allow a higher degree of automation. The algebra has been encoded in Isabelle/HOL to provide a basis for tool support for program verification. In rely/guarantee concurrency, programs are specified to guarantee certain behaviours until assumptions about the behaviour of their environment are violated. When assumptions are violated, program behaviour is unconstrained (aborting), and guarantees need no longer hold. To support these guarantees a second synchronous operator, weak conjunction, was introduced: both processes in a weak conjunction must agree to take each atomic step, unless one aborts in which case the whole aborts. In developing the laws for parallel and weak conjunction we found many properties were shared by the operators and that the proofs of many laws were essentially the same. This insight led to the idea of generalising synchronisation to an abstract operator with only the axioms that are shared by the parallel and weak conjunction operator, so that those two operators can be viewed as instantiations of the abstract synchronisation operator. The main differences between parallel and weak conjunction are how they combine individual atomic steps; that is left open in the axioms for the abstract operator.Comment: Extended version of a Formal Methods 2016 paper, "An algebra of synchronous atomic steps

Balancing Efficiency, Equity, and Voice in Workplace Resolution Procedures

Systems for resolving workplace disputes are very important to workers and firms, and have been the subject of much debate. In the United States, traditional unionized grievance procedures, emerging nonunion dispute resolution systems, and the court-based system for resolving employment law disputes have all been criticized. Much of the existing debate on workplace dispute resolution, however, has been atheoretical, with a focus on techniques of dispute resolution rather than the goals of the system. What is missing from the debate are fundamental standards for comparing and evaluating dispute resolutions systems. In this paper, we develop efficiency, equity, and voice as these standards. Unionized, nonunion, and employment law procedures are then evaluated against these three standards.

Alien Registration- Colvin, John J. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/26625/thumbnail.jp

Alien Registration- Colvin, John J. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/26625/thumbnail.jp

Alien Registration- Colvin, John J. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/26625/thumbnail.jp

HIV/AIDS, chronic diseases and globalisation

HIV/AIDS has always been one of the most thoroughly global of diseases. In the era of widely available anti-retroviral therapy (ART), it is also commonly recognised as a chronic disease that can be successfully managed on a long-term basis. This article examines the chronic character of the HIV/AIDS pandemic and highlights some of the changes we might expect to see at the global level as HIV is increasingly normalised as "just another chronic disease". The article also addresses the use of this language of chronicity to interpret the HIV/AIDS pandemic and calls into question some of the consequences of an uncritical acceptance of concepts of chronicity

The Relationship Between Employment Arbitration and Workplace Dispute Resolution Procedures

Published in cooperation with the American Bar Association Section of Dispute Resolutio