Search

Edge computing is a promising computing paradigm by pushing the cloud service to the network edge. To this end, edge infrastructure providers (EIPs) need to bring computation and storage resources to the network edge and allow edge service providers (ESPs) to provision latency-critical services for end users. Currently, EIPs prefer to establish a series of private edge-computing environments to serve specific requirements of users. This kind of resource provisioning mechanism severely limits the development and spread of edge computing in serving diverse user requirements. In this paper, we propose an integrated resource provisioning model, named edge federation, to seamlessly realize the resource cooperation and service provisioning across standalone edge computing providers and clouds. To efficiently schedule and utilize the resources across multiple EIPs, we systematically characterize the provisioning process as a large-scale linear programming (LP) problem and transform it into an easily solved form. Accordingly, we design a dynamic algorithm to tackle the varying service demands from users. We conduct extensive experiments over the base station networks in Toronto. Compared with the fixed contract model and multihoming model, edge federation can reduce the overall costs of EIPs by 23.3% to 24.5%, and 15.5% to 16.3%, respectively. [ABSTRACT FROM AUTHOR]

With the rapid proliferation of cloud computing, the energy cost of datacenters and the impact of reactive power on the grid have become major concerns. This paper presents two energy management control schemes for distributed uninterruptible power supply (UPS) architectures utilizing lithium-ion ultracapacitors (LIC) for improved system efficiency and reactive power mitigation. One scheme is proposed for low-power servers with an internal dc bus, while another is proposed for medium-to-high-power server racks with an in-rack dc bus. The LIC and the dc bus interface with a bidirectional dc–dc converter, which allows the power supply unit to run in the optimal operating region for the improved system efficiency and power factor. The server-level UPS architecture is experimentally tested using a 200-kHz, bidirectional, multiphase dc–dc converter with hysteretic current-mode control, while achieving 33% reactive power mitigation. Based on the SciNet datacenter in Toronto, ON, Canada, a rack-level distributed UPS architecture is built in MATLAB, and system-level simulations indicate a 37% reduction in the reactive power. [ABSTRACT FROM AUTHOR]

The peak current estimation of lightning detection networks for strikes to tall towers is discussed in this paper. Such systems are sometimes calibrated using return-stroke current data obtained by means of rocket-triggered lightning or instrumented towers of relatively short height. However, for strikes to electrically tall towers, they tend to overestimate the return-stroke current peak. In this case, in fact, the associated radiated electromagnetic fields, from which the return-stroke current is estimated, experience a significant enhancement with respect to the field that would be radiated if the same return stroke was initiated at ground level or on a short tower. Two approaches to correct the current estimates of a lightning detection network for a lightning strike to a tall tower are discussed and applied to the current measurements obtained at the CN Tower in Toronto in the summer of 2005, for which estimates were available from the North American Lightning Detection Network (NALDN). It is shown that correcting the NALDN estimates using the so-called tower factor obtained from theoretical studies results in an excellent estimation of lightning current peaks. [ABSTRACT FROM AUTHOR]

Sure we want exceptional journals, carefully reviewed so we will not have to waste weeks delving into a paper that turns out to be smoke and mirrors. We also want some services that reflect the dues we pay to belong to the Society. However, nothing in the AP Society leaves us with a feeling of exhilaration like a good conference, and the Toronto conference, which as I write this article was a recent experience, met our expectations in every way. Many thanks to the conference Chair, George Eleftheriades; Vice-Chair, Ravi Adve; Technical Program Chair, Lot Shafai; and all the other conference committee members that helped to make the 2010 IEEE AP-S/URSI Symposium the highlight event of the year for the Society. Something that really makes the conference committee feel good about the five years of hard work and planning are the appreciative e-mails that are sent after the event. George should be recovered enough to be able to open his e-mail by the time you read this, so if you have been thinking about how much you enjoyed the experience, please send him a note at gelefth@waves.utoronto.ca. Also, if you have some suggestions as to how we can improve the annual North American summer Symposium, our Meetings Chair, Jeff. Young Gyoung@mrc.uidaho.edu), would very much like to have your input. [ABSTRACT FROM PUBLISHER]