Sustaining a federation of future internet experimental facilities

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Evaluator services for optimised service placement in distributed heterogeneous cloud infrastructures

Optimal placement of demanding real-time interactive applications in a distributed heterogeneous cloud very quickly results in a complex tradeoff between the application constraints and resource capabilities. This requires very detailed information of the various requirements and capabilities of the applications and available resources. In this paper, we present a mathematical model for the service optimization problem and study the concept of evaluator services as a flexible and efficient solution for this complex problem. An evaluator service is a service probe that is deployed in particular runtime environments to assess the feasibility and cost-effectiveness of deploying a specific application in such environment. We discuss how this concept can be incorporated in a general framework such as the FUSION architecture and discuss the key benefits and tradeoffs for doing evaluator-based optimal service placement in widely distributed heterogeneous cloud environments

How many young star clusters exist in the Galactic center?

We study the evolution and observability of young compact star clusters within about 200pc of the Galactic center. Calculations are performed using direct N-body integration on the GRAPE-4, including the effects of both stellar and binary evolution and the external influence of the Galaxy. The results of these detailed calculations are used to calibrate a simplified model applicable over a wider range of cluster initial conditions. We find that clusters within 200 pc from the Galactic center dissolve within about 70 Myr. However, their projected densities drop below the background density in the direction of the Galactic center within 20 Myr, effectively making these clusters undetectable after that time. Clusters farther from the Galactic center but at the same projected distance are more strongly affected by this selection effect, and may go undetected for their entire lifetimes. Based on these findings, we conclude that the region within 200 pc of the Galactic center could easily harbor some 50 clusters with properties similar to those of the Arches or the Quintuplet systems.Comment: ApJ Letters in pres

Breed differences in the pharmacokinetics of ivermectin administered subcutaneously to Holstein and Belgian Blue calves

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Service oriented networking

This paper introduces a new paradigm for service oriented networking being developed in the FUSION project(1). Despite recent proposals in the area of information centric networking, a similar treatment of services - where networked software functions, rather than content, are dynamically deployed, replicated and invoked - has received little attention by the network research community to date. Our approach provides the mechanisms required to deploy a replicated service instance in the network and to route client requests to the closest instance in an efficient manner. We address the main issues that such a paradigm raises including load balancing, resource registration, domain monitoring and inter-domain orchestration. We also present preliminary evaluation results of current work

Service-centric networking

This chapter introduces a new paradigm for service centric networking. Building upon recent proposals in the area of information centric networking, a similar treatment of services – where networked software functions, rather than content, are dynamically deployed, replicated and invoked – is discussed. Service-centric networking provides the mechanisms required to deploy replicated service instances across highly distributed networked cloud infrastructures and to route client requests to the closest instance while providing more efficient network infrastructure usage, improved QoS and new business opportunities for application and service providers. </jats:p

Flow-Field Investigation of Gear-Flap Interaction on a Gulfstream Aircraft Model

Off-surface flow measurements of a high-fidelity 18% scale Gulfstream aircraft model in landing configuration with the main landing gear deployed are presented. Particle Image Velocimetry (PIV) and Laser Velocimetry (LV) were used to measure instantaneous velocities in the immediate vicinity of the main landing gear and its wake and near the inboard tip of the flap. These measurements were made during the third entry of a series of tests conducted in the NASA Langley Research Center (LaRC) 14- by 22-Foot Subsonic Tunnel (14 x 22) to obtain a comprehensive set of aeroacoustic measurements consisting of both aerodynamic and acoustic data. The majority of the off-body measurements were obtained at a freestream Mach number of 0.2, angle of attack of 3 degrees, and flap deflection angle of 39 degrees with the landing gear on. A limited amount of data was acquired with the landing gear off. LV was used to measure the velocity field in two planes upstream of the landing gear and to measure two velocity profiles in the landing gear wake. Stereo and 2-D PIV were used to measure the velocity field over a region extending from upstream of the landing gear to downstream of the flap trailing edge. Using a special traverse system installed under the tunnel floor, the velocity field was measured at 92 locations to obtain a comprehensive picture of the pertinent flow features and characteristics. The results clearly show distinct structures in the wake that can be associated with specific components on the landing gear and give insight into how the wake is entrained by the vortex at the inboard tip of the flap

A Deep-Sea Sponge Loop? Sponges Transfer Dissolved and Particulate Organic Carbon and Nitrogen to Associated Fauna

Cold-water coral reefs and sponge grounds are deep-sea biological hotspots, equivalent to shallow-water tropical coral reefs. In tropical ecosystems, biodiversity and productivity are maintained through efficient recycling pathways, such as the sponge loop. In this pathway, encrusting sponges recycle dissolved organic matter (DOM) into particulate detritus. Subsequently, the sponge-produced detritus serves as a food source for other organisms on the reef. Alternatively, the DOM stored in massive sponges was recently hypothesized to be transferred to higher trophic levels through predation of these sponges, instead of detritus production. However, for deep-sea sponges, the existence of all prerequisite, consecutive steps of the sponge loop have not yet been established. Here, we tested whether cold-water deep-sea sponges, similar to their tropical shallow-water counterparts, take up DOM and transfer assimilated DOM to associated fauna via either detritus production or predation. We traced the fate of 13carbon (C)- and 15nitrogen (N)-enriched DOM and particulate organic matter (POM) in time using a pulse-chase approach. During the 24-h pulse, the uptake of 13C/15N-enriched DOM and POM by two deep-sea sponge species, the massive species Geodia barretti and the encrusting species Hymedesmia sp., was assessed. During the subsequent 9-day chase in label-free seawater, we investigated the transfer of the consumed food by sponges into brittle stars via two possible scenarios: (1) the production and subsequent consumption of detrital waste or (2) direct feeding on sponge tissue. We found that particulate detritus released by both sponge species contained C from the previously consumed tracer DOM and POM, and, after 9-day exposure to the labeled sponges and detritus, enrichment of 13C and 15N was also detected in the tissue of the brittle stars. These results therefore provide the first evidence of all consecutive steps of a sponge loop pathway via deep-sea sponges. We cannot distinguish at present whether the deep-sea sponge loop is acting through a detrital or predatory pathway, but conclude that both scenarios are feasible. We conclude that sponges could play an important role in the recycling of DOM in the many deep-sea ecosystems where they are abundant, although in situ measurements are needed to confirm this hypothesis.publishedVersio