2,821 research outputs found
ADVANCED TECHNOLOGY AND KNOWLEDGE TRANSFER
This paper reports on a specific project, employing new technological capabilities to better transfer expert knowledge. The specific project considered for the paper is the World Initiative for Soy in Human Health (WISHH), a Multi Organization Enterprise promoting the use of soy and soy products in humanitarian and development aid around the world. VisIT, which stands for Visualization of Information Technology, is a potentially powerful organizational tool. It is compared against the traditional technology in the WISHH setting. An evaluation experiment was conducted with undergraduate students enrolled in agriculture and consumer economics and management courses in January and February 2002. The paper provides the summary results of the effectiveness of the use of that technology to transfer expert knowledge.Research and Development/Tech Change/Emerging Technologies,
Fundamental Limits of Caching with Secure Delivery
Caching is emerging as a vital tool for alleviating the severe capacity
crunch in modern content-centric wireless networks. The main idea behind
caching is to store parts of popular content in end-users' memory and leverage
the locally stored content to reduce peak data rates. By jointly designing
content placement and delivery mechanisms, recent works have shown order-wise
reduction in transmission rates in contrast to traditional methods. In this
work, we consider the secure caching problem with the additional goal of
minimizing information leakage to an external wiretapper. The fundamental cache
memory vs. transmission rate trade-off for the secure caching problem is
characterized. Rather surprisingly, these results show that security can be
introduced at a negligible cost, particularly for large number of files and
users. It is also shown that the rate achieved by the proposed caching scheme
with secure delivery is within a constant multiplicative factor from the
information-theoretic optimal rate for almost all parameter values of practical
interest
Retroactive Anti-Jamming for MISO Broadcast Channels
Jamming attacks can significantly impact the performance of wireless
communication systems. In addition to reducing the capacity, such attacks may
lead to insurmountable overhead in terms of re-transmissions and increased
power consumption. In this paper, we consider the multiple-input single-output
(MISO) broadcast channel (BC) in the presence of a jamming attack in which a
subset of the receivers can be jammed at any given time. Further,
countermeasures for mitigating the effects of such jamming attacks are
presented. The effectiveness of these anti-jamming countermeasures is
quantified in terms of the degrees-of-freedom (DoF) of the MISO BC under
various assumptions regarding the availability of the channel state information
(CSIT) and the jammer state information at the transmitter (JSIT). The main
contribution of this paper is the characterization of the DoF region of the two
user MISO BC under various assumptions on the availability of CSIT and JSIT.
Partial extensions to the multi-user broadcast channels are also presented.Comment: submitted to IEEE Transactions on Information Theor
Crack stability in the fracture of cementitious materials
The aim of the present study is to investigate the stability of crack propagation in cementitious materials. Tests were conducted on bend specimens in three-point and four-point loading conditions. Three-point bend specimens showed stable crack growth for mortar, normal strength and high strength concrete specimens. Alternatively, four-point bend specimens showed catastrophic failure for mortar and quasi-catastrophic failure for normal strength and high strength concrete specimens. Results will be discussed in relation to brittleness number model and specific microstructural features including the interfacial transition zone between the cement paste and the aggregate and the attendant toughening mechanisms
Bay of Bengal: From monsoons to mixing
The Bay of Bengal has a surprisingly large influence on the world. It nurtures the South Asian summer monsoon, a tremendous ocean-atmosphere-land phenomenon that delivers freshwater to more than a third of the human population
on this planet. During summer, southwesterly winds gather moisture from the ocean and carry it deep inland over the
Indian subcontinent, bringing welcome rains to a parched land. During winter, the winds reverse to northeasterly, and
the ocean circulation responds by dispersing the terrestrial freshwater run off concentrated in the northern part of the
bay
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