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Institution

Worcester Polytechnic Institute

EducationWorcester, Massachusetts, United States
About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Population & Data envelopment analysis. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.


Papers
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Journal ArticleDOI
TL;DR: In this article, a beam-to-core size ratio exceeding 175 may be achieved for optical vortex-vortex interactions within a laser beam by minimizing the size of the core.
Abstract: An optical-vortex filament is characterized by a dark core of vanishing size and fluidlike propagation dynamics in the near-field region. This type of phase singularity does not naturally occur as an eigenmode of a cylindrically symmetric system, but it can be easily formed by computer-generated holography. The size of the core is an important attribute affecting vortex–vortex interactions within a laser beam. Here we demonstrate a means to minimize the core size, and we experimentally show that a beam-to-core size ratio exceeding 175 may be readily achieved.

158 citations

Proceedings ArticleDOI
01 Oct 1999
TL;DR: It is found that jitter degrades perceptual quality nearly as much as does packet loss, and that perceptual quality degrades sharply even with low 1eveIs of jitter or packet loss as compared to perceptual quality for perfect video.
Abstract: Today’s powerful computers and networks present the opportunity for video across the Internet right to the desktop. However, Internet video often suffers from packet loss and jitter, degrading the user’s perceived quality of the video. Understanding the effects of delay, loss and jitter on media quality is critical for choosing delay buffer sizes and packet repair techniques. While the effects of packet loss on perceptual quality are well-understood, to date there have not been careful user studies measuring the impact of jitter on perceptual quality. The major contributions of this work are carefully designed experiments that measure and compare the impact of both jitter and packet loss on perceptual quality of packet video. We find that jitter degrades perceptual quality nearly as much as does packet loss, and that perceptual quality degrades sharply even with low 1eveIs of jitter or packet loss as compared to perceptual quality for perfect video.

158 citations

Journal ArticleDOI
TL;DR: Results indicate that integration of Sb:SnO2 nanorod cores with other successful strategies such as doping and coating with oxygen evolution catalysts can move the performance of BiVO4 and related semiconductors closer to their theoretical potential.
Abstract: BiVO4 has become the top-performing semiconductor among photoanodes for photoelectrochemical water oxidation. However, BiVO4 photoanodes are still limited to a fraction of the theoretically possible photocurrent at low applied voltages because of modest charge transport properties and a trade-off between light absorption and charge separation efficiencies. Here, we investigate photoanodes composed of thin layers of BiVO4 coated onto Sb-doped SnO2 (Sb:SnO2) nanorod-arrays (Sb:SnO2/BiVO4 NRAs) and demonstrate a high value for the product of light absorption and charge separation efficiencies (ηabs × ηsep) of ∼51% at an applied voltage of 0.6 V versus the reversible hydrogen electrode, as determined by integration of the quantum efficiency over the standard AM 1.5G spectrum. To the best of our knowledge, this is one of the highest ηabs × ηsep efficiencies achieved to date at this voltage for nanowire-core/BiVO4-shell photoanodes. Moreover, although WO3 has recently been extensively studied as a core nanowire...

158 citations

Proceedings ArticleDOI
01 Apr 2006
TL;DR: A location-aware end-to-end security framework in which secret keys are bound to geographic locations and each node stores a few keys based on its own location, which effectively limits the impact of compromised nodes only to their vicinity without affecting end- to-end data security.
Abstract: Providing desirable data security, that is, confidentiality, authenticity, and availability, in wireless sensor networks (WSNs) is challenging, as a WSN usually consists of a large number of resource constraint sensor nodes that are generally deployed in unattended/hostile environments and, hence, are exposed to many types of severe insider attacks due to node compromise. Existing security designs mostly provide a hop-by-hop security paradigm and thus are vulnerable to such attacks. Furthermore, existing security designs are also vulnerable to many types of Denial of Service (DoS) attacks, such as report disruption attacks and selective forwarding attacks and thus put data availability at stake. In this paper, we seek to overcome these vulnerabilities for large-scale static WSNs. We come up with a location-aware end-to-end security framework in which secret keys are bound to geographic locations and each node stores a few keys based on its own location. This location-aware property effectively limits the impact of compromised nodes only to their vicinity without affecting end-to-end data security. The proposed multifunctional key management framework assures both node-to-sink and node-to-node authentication along the report forwarding routes. Moreover, the proposed data delivery approach guarantees efficient en-route bogus data filtering and is highly robust against DoS attacks. The evaluation demonstrates that the proposed design is highly resilient against an increasing number of compromised nodes and effective in energy savings. Index Terms—Data security, wireless sensor network, end-to-end, DoS attack, false-data injection attack.

158 citations

Journal ArticleDOI
TL;DR: Results for drag coefficient and heat flow for flow past sphere–sphere and wall-sphere contact points for CFD simulations of transport in fixed beds of spheres, focusing on higher flow rates typical of industrial steam reformers.

158 citations


Authors

Showing all 6336 results

NameH-indexPapersCitations
Andrew G. Clark140823123333
Ming Li103166962672
Joseph Sarkis10148245116
Arthur C. Graesser9561438549
Kevin J. Harrington8568233625
Kui Ren8350132490
Bart Preneel8284425572
Ming-Hui Chen8252529184
Yuguang Fang7957220715
Wenjing Lou7731129405
Bernard Lown7333020320
Joe Zhu7223119017
Y.S. Lin7130416100
Kevin Talbot7126815669
Christof Paar6939921790
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202326
202295
2021762
2020836
2019761
2018703