Representing eager evaluation in a demand driven model of streams on cloud infrastructure

Previously, we developed our StreamComponents framework which uses distributed components and web services to facilitate control, reconfiguration and deployment of streams on both local clusters, and remote cloud infrastructure. Our stream evaluation semantics are fundamentally demand driven, a conservative view that ensures no unnecessary computation, supports flexible structures such as cyclic networks and infinite streams, and facilitates resource management. Abstract In this paper, we focus on the evaluation semantics of our stream model, and explore circumstances under which more eager evaluation is desirable, whilst retaining the fundamental semantics. We introduce the Indirected Asynchronous Method pattern (IAM), which makes novel use of futures and auto-continuations, to facilitate fully asynchronous demand propagation leading to more eager evaluation of the streams. We present an evaluation of the model on both cluster and cloud infrastructure showing that very useful amounts of pipelining parallelism can be achieved.Paul Martinaitis and Andrew Wendelbor

Stream-components: component based stream computation on the grid

This paper reports on an investigation into component-based design in object-oriented distributed systems. We focus on the modeling of stream processing in terms of components (as exemplified in the EU CoreGrid project ProActive), to show how a stream processing system can be built from objects, and components in composition. In particular, we explore mechanisms for dynamic reconfiguration and distributed management of streams in a grid context. In further work, we will examine the relationship of such design to grid workflows and web services.Paul N. Martinaitis and Andrew L. Wendelbor

Component-based stream processing "in the cloud"

In earlier work, we reported on modeling of stream processing in terms of distributed components (as exemplified in the EU CoreGrid project ProActive), showing how a stream processing system can be built from components in composition, with dynamic reconfiguration and distributed management of the streams. In this paper, we introduce the Web Service Stream Deployer (WSSD), for the remote establishment and deployment of streams across widely distributed resources, allowing a user to set-up, control and reconfigure a stream remotely and dynamically. We demonstrate this concept with streams on a cloud testbed, using Nimbus cloud infrastructure at the University of Chicago. In particular, we show that our web-services based WSSD exhibits minimal adverse latency effect when used over an intercontinental network to manipulate, from our client in Australia, a cloud-based stream in the USA; we believe that this represents a useful mode of remote interaction with cloud-based applications. We outline some ideas in scheduling of cloud-based streams; we present a model of interaction with Gridbus, a widely used framework for exploring different scheduling algorithms (such as economic scheduling), whereby scheduling criteria expressed in Gridbus can be used to automatically deploy stream components.Paul N. Martinaitis, Craig J. Patten, Andrew L. Wendelbor

The age of the Pooraka formation and its implications, with some preliminary results from luminescence dating

Stratigraphic relationships, supported by luminescence dating, suggest that the Pooraka Formation spans a far greater time interval than previously recognised on the basis of radiocarbon dating and stratigraphic analysis of discrete sedimentary sections. It extends back as far as the Last Interglacial. Re-evaluation of the radiocarbon ages that indicate an interstadial age (i.e. Oxygen Isotope Stage 3; 45 to 30 ka BP) for the sediments is required. Alternatively, a considerable time interval for deposition of the Pooraka Formation would necessitate that the unit be diachronous across the landscape. An age extending back to the Last Interglacial (Oxygen Isotope Substage 5c; c. 125 ka BP) would provide the appropriate palaeo-climates and palaeo-environments for fluvial sedimentation. The revised age has implications for landscape evolution, archaeological and palaeomagnetic prospecting as well as the antiquity of the Diprotodon in the Adelaide area

The age of the Pooraka Formation and its implications, with some preliminary results for luminescence dating

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