47,510 research outputs found
The Global Employer: How to Respond to a Global Crisis
This publication has been prepared for clients and professional associates of Baker & McKenzie. It is intended to provide only a summary of selected legal developments. For this reason the information contained in this publication should not form the basis of any decision as to a particular course of action; nor should it be relied on as legal advice or regarded as a substitute for detailed advice in individual cases. The services of a competent professional adviser should be obtained in each instance so that the applicability of the relevant legislation or other legal development to the particular facts can be verified
Redundancy Strategies for a High Splitting Optically Amplified Passive Optical Network
Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.High splitting, optically amplified, passive optical networks (SuperPONs) are investigated in terms of redundancy provision and protection mechanisms. Options for redundancy, including the important special case of dual homing, are detailed, and it is determined as to which of these options (duplication of the feeder and first distribution section, and N+1 protection of the optical amplifiers in the amplified splitter) would be required to be provided to all attached users to facilitate appropriate availability of the basic telephony service. The distributed amplified splitter dual homing solution is found to outperform the single amplified splitter solution in terms of its survivability. The protection mechanisms necessary to automatically switch to the redundant provision are discussed and it is seen that with the aid of suitable regular precautionary procedures protection switching can generally be provided rapidly (<50 ms). Finally, an availability, and cost versus availability, study confirms the aforementioned redundancy assessment for fiber-to-the-home (FTTH) implementations, but shows fiber-to-the-curb (FTTC) as needing additional redundancyPeer reviewe
LAGC: Lazily Aggregated Gradient Coding for Straggler-Tolerant and Communication-Efficient Distributed Learning
Gradient-based distributed learning in Parameter Server (PS) computing
architectures is subject to random delays due to straggling worker nodes, as
well as to possible communication bottlenecks between PS and workers. Solutions
have been recently proposed to separately address these impairments based on
the ideas of gradient coding, worker grouping, and adaptive worker selection.
This paper provides a unified analysis of these techniques in terms of
wall-clock time, communication, and computation complexity measures.
Furthermore, in order to combine the benefits of gradient coding and grouping
in terms of robustness to stragglers with the communication and computation
load gains of adaptive selection, novel strategies, named Lazily Aggregated
Gradient Coding (LAGC) and Grouped-LAG (G-LAG), are introduced. Analysis and
results show that G-LAG provides the best wall-clock time and communication
performance, while maintaining a low computational cost, for two representative
distributions of the computing times of the worker nodes.Comment: Submitte
Safetynet version 2, a packet error recovery architecture for vertical handoffs
Mobile devices are connecting to the Internet through an increasingly heterogeneous network environment. This connectivity via multiple types of wireless networks allows the mobile devices to take advantage of the high speed and the low cost of wireless local area networks and the large coverage of wireless wide area networks. To maximize the benefits from these complementing characteristics, the mobile devices need to be able to switch seamlessly between the different network types. However, the switch between the technologies, also known as a vertical handoff, often results in significant packet loss and degradation of connectivity due to handoff delay and also increased packet loss rate on the border of the coverage area of the networks. In our previous work, we have proposed an inter technology mobility management architecture which addresses the packet losses using selective resending of packets lost during the handoff period. In this paper, we extend the architecture to address packet losses due to wireless errors more efficiently by taking advantage of erasure codes to form redundancy packets. We propose to send these redundancy packets over both links. We show that this proposal reduces both the chances of packet loss and the buffering requirements of the original Safetynet scheme
Cycle time optimization by timing driven placement with simultaneous netlist transformations
We present new concepts to integrate logic synthesis and physical design. Our methodology uses general Boolean transformations as known from technology-independent synthesis, and a recursive bi-partitioning placement algorithm. In each partitioning step, the precision of the layout data increases. This allows effective guidance of the logic synthesis operations for cycle time optimization. An additional advantage of our approach is that no complicated layout corrections are needed when the netlist is changed
Network Coding Over SATCOM: Lessons Learned
Satellite networks provide unique challenges that can restrict users' quality
of service. For example, high packet erasure rates and large latencies can
cause significant disruptions to applications such as video streaming or
voice-over-IP. Network coding is one promising technique that has been shown to
help improve performance, especially in these environments. However,
implementing any form of network code can be challenging. This paper will use
an example of a generation-based network code and a sliding-window network code
to help highlight the benefits and drawbacks of using one over the other.
In-order packet delivery delay, as well as network efficiency, will be used as
metrics to help differentiate between the two approaches. Furthermore, lessoned
learned during the course of our research will be provided in an attempt to
help the reader understand when and where network coding provides its benefits.Comment: Accepted to WiSATS 201
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