pony - The occam-pi Network Environment

Although concurrency is generally perceived to be a `hard' subject, it can in fact be very simple --- provided that the underlying model is simple. The occam-pi parallel processing language provides such a simple yet powerful concurrency model that is based on CSP and the pi-calculus. This paper presents pony, the occam-pi Network Environment. occam-pi and pony provide a new, unified, concurrency model that bridges inter- and intra-processor concurrency. This enables the development of distributed applications in a transparent, dynamic and highly scalable way. The first part of this paper discusses the philosophy behind pony, explains how it is used, and gives a brief overview of its implementation. The second part evaluates pony's performance by presenting a number of benchmarks

Spatiotemporal Zones of Neosomnambulism

Drawing on Deleuze and Guattari’s(1994)methodology developed in their swansong, What is Philosophy?this article deploys its own conceptual persona: the Neosomnambulist or new sleepwalker.Not to be mistaken for an actual living person, the Neosomnambulist is utilized so as to bring concepts tolife.1In this case, what the sleepwalker gives life toare spatiotemporal zones ofindistinctionthat pervade the digital now

Process-Oriented Collective Operations

Distributing process-oriented programs across a cluster of machines requires careful attention to the effects of network latency. The MPI standard, widely used for cluster computation, defines a number of collective operations: efficient, reusable algorithms for performing operations among a group of machines in the cluster. In this paper, we describe our techniques for implementing MPI communication patterns in process-oriented languages, and how we have used them to implement collective operations in PyCSP and occam-pi on top of an asynchronous messaging framework. We show how to make use of collective operations in distributed processoriented applications. We also show how the process-oriented model can be used to increase concurrency in existing collective operation algorithms

Regulation, institutions and commitment : the Jamaican telecommunications sector

The Jamaican telecommunications sector today is much more dynamic than it was before and provides much better service. There is widespread skepticism about the current regulatory framework, which is criticized for encouraging a tight telecommunications monopoly, little administrative discretion, and continous price adjustments to satisfy what many see as a high rate of return requirement. But the authors suggest that the regulatory framework is a"second-best"alternative, a pragmatic response to The Jamaican's institutional realities. The authors analyze why the reforms of the late 1980s took the form they did, and whether they could have been better. They find that the changing nature of regulatory institutions, ownership arrangements, and sector performance in the past 50 years is traceable to intense contracting problems between firms or interest groups and the government. Attempts to resolves these contracting problems have continuously constrained the government's (and firms) ability to implement efficient pricing schemes. In the abstract, The Jamaican's regulatory structure looks inefficient. In the context of The Jamaican's political system, politics, judiciary, bureaucracy, and interest groups, the regulatory framework developed in the late 1980s emerges as a fairly pragmatic, welfare-improving set of policies. Perhaps it could have been better, but its current design reflects basic commitment problems the government has with public utilities.Public Sector Economics&Finance,Economic Theory&Research,National Governance,Environmental Economics&Policies,ICT Policy and Strategies

Constraining the Solution to the Last Parsec Problem with Pulsar Timing

The detection of a stochastic gravitational-wave signal from the superposition of many inspiraling supermassive black holes with pulsar timing arrays (PTAs) is likely to occur within the next decade. With this detection will come the opportunity to learn about the processes that drive black-hole-binary systems toward merger through their effects on the gravitational-wave spectrum. We use Bayesian methods to investigate the extent to which effects other than gravitational-wave emission can be distinguished using PTA observations. We show that, even in the absence of a detection, it is possible to place interesting constraints on these dynamical effects for conservative predictions of the population of tightly bound supermassive black-hole binaries. For instance, if we assume a relatively weak signal consistent with a low number of bound binaries and a low black-hole-mass to galaxy-mass correlation, we still find that a non-detection by a simulated array, with a sensitivity that should be reached in practice within a few years, disfavors gravitational-wave-dominated evolution with an odds ratio of $\sim$30:1. Such a finding would suggest either that all existing astrophysical models for the population of tightly bound binaries are overly optimistic, or else that some dynamical effect other than gravitational-wave emission is actually dominating binary evolution even at the relatively high frequencies/small orbital separations probed by PTAs.Comment: 14 pages, 8 figure

OpenForensics:a digital forensics GPU pattern matching approach for the 21st century

Pattern matching is a crucial component employed in many digital forensic (DF) analysis techniques, such as file-carving. The capacity of storage available on modern consumer devices has increased substantially in the past century, making pattern matching approaches of current generation DF tools increasingly ineffective in performing timely analyses on data seized in a DF investigation. As pattern matching is a trivally parallelisable problem, general purpose programming on graphic processing units (GPGPU) is a natural fit for this problem. This paper presents a pattern matching framework - OpenForensics - that demonstrates substantial performance improvements from the use of modern parallelisable algorithms and graphic processing units (GPUs) to search for patterns within forensic images and local storage devices

The Operational Loops of a Pandemic

This article analyses the visual operations of contagions and their material aftereffects. Data visualizations and diagrams have played a key role in the visual culture of the contagion, and this article explores especially two recurring themes: curves and simulations. The article will address the data diagrams that describe and predict, advise and control actions during the pandemic. We argue that these curves and simulations are also crucial epistemic and aesthetic occurrences that produce the long tail of the epidemic as it pertains to a variety of actions from policy-making to affective responses. Furthermore, the text investigates the theme of the operational loop in order to help us to grasp statistical curves and simulations as part of a multi-scalar logics of the epidemic image and in order to discuss the temporal modalities of these various images and diagrams. The article also includes David Benqué’s speculative diagrams of contagions loops that present an artistic response to the theoretical theme