ACTORS: A Model of Concurrent Computation in Distributed Systems

A foundational model of concurrency is developed in this thesis. We examine issues in the design of parallel systems and show why the actor model is suitable for exploiting large-scale parallelism. Concurrency in actors is constrained only by the availability of hardware resources and by the logical dependence inherent in the computation. Unlike dataflow and functional programming, however, actors are dynamically reconfigurable and can model shared resources with changing local state. Concurrency is spawned in actors using asynchronous message-passing, pipelining, and the dynamic creation of actors. This thesis deals with some central issues in distributed computing. Specifically, problems of divergence and deadlock are addressed. For example, actors permit dynamic deadlock detection and removal. The problem of divergence is contained because independent transactions can execute concurrently and potentially infinite processes are nevertheless available for interaction.

Social Networks and Actors

A discussion about Actor Network Theory

Els actors del turisme escolar. 'Los actores del turismo escolar'.

Se presentan los diferentes agentes que están relacionados con el turismo escolar. Museos, empresas de servicios o talleres son algunos de los ámbitos analizados para entender mejor el fenómeno de turismo escolar, con una cuota muy importante de desplazamientos en Cataluña.

Actors and objects: A socio-technical networks approach for construction management research

We explore the contribution of socio-technical networks approaches to construction management research. These approaches are distinctive for their analysis of actors and objects as mutually constituted within socio-technical networks. They raise questions about the ways in which the content, meaning and use of technology is negotiated in practice, how particular technical configurations are elaborated in response to specific problems and why certain paths or solutions are adopted rather than others. We illustrate this general approach with three case studies: a historical study of the development of reinforced concrete in France, the UK and the US, the recent introduction of 3D-CAD software into four firms and an analysis of the uptake of environmental assessment technologies in the UK since 1990. In each we draw out the ways in which various technologies shaped and were shaped by different socio-technical networks. We conclude with a reflection on the contributions of socio-technical network analysis for more general issues including the study of innovation and analyses of context and power.

An examination of actors that impact technology introduction to FM

Developing and implementing a technology for Facilities Management (FM) can be a complex process. This is particularly the case when a technology impacts on an organisation as a whole. There are often a number of relevant actors, internal and external to FM, who should be engaged. This engagement is guided by the strategy of the organisation which is led by top management decisions. Indeed, it is top management who have the final decision to implement a technology. Actors of top management and other relevant actors will have their own discourses toward the implementation of the technology based on how they foresee the technology befittingly benefitting the organisation. This paper examines actors who play a relevant and necessary part in supporting and implementing a technology to FM. It examines how an actor’s discourse toward the project inhibits or speeds up the implementation of a technology. The methods used for this paper are based on a two year case study in a FM department where a technology development was observed and interviews with key participants were conducted. Critical discourse analysis is used to analyse the data. Prominent discourses that emerge from the data are emphasised during the process of introducing the technology. This research moves beyond focusing purely on project successes but examines the difficulties and the hurdles that must be overcome to reach a successful technology implementation.