The ambient calculus is a process calculus for describing mobile com putation We develop a theory of Morris style contextual equivalence for proving properties of mobile ambients We prove a context lemma that allows derivation of contextual equivalences by considering contexts of a particular limited form rather than all arbitrary contexts We give an activity lemma that characterizes the possib...

A method of preserving the sequential semantics in parallel pro grams with rst class continuations is to invoke continuations non speculati vely This method which prevents a continuation from being invoked as long as its invocation can infringe the sequential semantics reduces parallelism by the severe conditions that it imposes especially on upward uses In this paper we present new conditions ...

We develop a theory of bisimulations for a simple language containing communicating transactions, obtained by dropping the isolation requirement of standard transactions. Such constructs have emerged as a useful programming abstraction for distributed systems. In systems with communicating transactions actions are tentative, waiting for certain transactions to commit before they become permanen...

We present a new type system with support for proofs of programs in a call-by-value language with control operators. The proof mechanism relies on observational equivalence of (untyped) programs. It appears in two type constructors, which are used for specifying program properties and for encoding dependent products. The main challenge arises from the lack of expressiveness of dependent product...

This paper presents the rules used within the Open PHACTS (http://www.openphacts.org) Identity Management Service to compute co-reference chains across multiple datasets. The web of (linked) data has encouraged a proliferation of identifiers for the concepts captured in datasets; with each dataset using their own identifier. A key data integration challenge is linking the co-referent identifier...

BACKGROUND From a philosophy of science perspective, the literature has posited that different research approaches influence field studies. Studies addressing interdisciplinary research have focused on the challenges of organizing and running interdisciplinary teams, cultural differences between and within disciplines, and constraints in conducting interdisciplinary research. Studies exploring ...

BACKGROUND As defined by evidence-based medicine randomized controlled trials rank higher than observational studies in the hierarchy of clinical research. Accordingly, when assessing the effects of treatments on patient outcomes, there is a tendency to focus on the study method rather than also appraising the key elements of study design. A long-standing debate regarding findings of randomized...

In recent years there has been much discussion of evidence based medicine and of the importance of randomised controlled trials. It may appear that observational research is a lesser method of inquiry, belonging to darker times before the dawn of this new paradigm. In this review we aim to describe to the practising emergency physician the current relevance of observational research within an e...