25,342 research outputs found
GraphH: High Performance Big Graph Analytics in Small Clusters
It is common for real-world applications to analyze big graphs using
distributed graph processing systems. Popular in-memory systems require an
enormous amount of resources to handle big graphs. While several out-of-core
approaches have been proposed for processing big graphs on disk, the high disk
I/O overhead could significantly reduce performance. In this paper, we propose
GraphH to enable high-performance big graph analytics in small clusters.
Specifically, we design a two-stage graph partition scheme to evenly divide the
input graph into partitions, and propose a GAB (Gather-Apply-Broadcast)
computation model to make each worker process a partition in memory at a time.
We use an edge cache mechanism to reduce the disk I/O overhead, and design a
hybrid strategy to improve the communication performance. GraphH can
efficiently process big graphs in small clusters or even a single commodity
server. Extensive evaluations have shown that GraphH could be up to 7.8x faster
compared to popular in-memory systems, such as Pregel+ and PowerGraph when
processing generic graphs, and more than 100x faster than recently proposed
out-of-core systems, such as GraphD and Chaos when processing big graphs
Multi-Layer Neural Networks for Quality of Service oriented Server-State Classification in Cloud Servers
Task allocation systems in the Cloud have been recently proposed so that their performance is optimised in real-time based on reinforcement learning with spiking Random Neural Networks (RNN). In this paper, rather than reinforcement learning, we suggest the use of multi-layer neural network architectures to infer the state of servers in a dynamic networked Cloud environment, and propose to select the most adequate server based on the task that optimises Quality of Service. First, a procedure is presented to construct datasets for state classification by collecting time-varying data from Cloud servers that have different resource configurations, so that the identification of server states is carried out with supervised classification. We test four distinct multi-layer neural network architectures to this effect: multi-layer dense clusters of RNNs (MLRNN), the hierarchical extreme learning machine (H-ELM), the multi-layer perceptron, and convolutional neural networks. Our experimental results indicate that server-state identification can be carried out efficiently and with the best accuracy using the MLRNN and H-ELM
Managing community membership information in a small-world grid
As the Grid matures the problem of resource discovery across communities,
where resources now include computational services, is becoming more
critical. The number of resources available on a world-wide grid is set to grow
exponentially in much the same way as the number of static web pages on
the WWW. We observe that the world-wide resource discovery problem can
be modelled as a slowly evolving very-large sparse-matrix where individual
matrix elements represent nodes’ knowledge of one another. Blocks in the
matrix arise where nodes offer more than one service. Blocking effects also
arise in the identification of sub-communities in the Grid. The linear algebra
community has long been aware of suitable representations of large, sparse
matrices. However, matrices the size of the world-wide grid potentially number
in the billions, making dense solutions completely intractable. Distributed
nodes will not necessarily have the storage capacity to store the addresses of
any significant percentage of the available resources. We discuss ways of modelling
this problem in the regime of a slowly changing service base including
phenomena such as percolating networks and small-world network effects
Fast and accurate object detection in high resolution 4K and 8K video using GPUs
Machine learning has celebrated a lot of achievements on computer vision
tasks such as object detection, but the traditionally used models work with
relatively low resolution images. The resolution of recording devices is
gradually increasing and there is a rising need for new methods of processing
high resolution data. We propose an attention pipeline method which uses two
staged evaluation of each image or video frame under rough and refined
resolution to limit the total number of necessary evaluations. For both stages,
we make use of the fast object detection model YOLO v2. We have implemented our
model in code, which distributes the work across GPUs. We maintain high
accuracy while reaching the average performance of 3-6 fps on 4K video and 2
fps on 8K video.Comment: 6 pages, 12 figures, Best Paper Finalist at IEEE High Performance
Extreme Computing Conference (HPEC) 2018; copyright 2018 IEEE; (DOI will be
filled when known
Wearable Communications in 5G: Challenges and Enabling Technologies
As wearable devices become more ingrained in our daily lives, traditional
communication networks primarily designed for human being-oriented applications
are facing tremendous challenges. The upcoming 5G wireless system aims to
support unprecedented high capacity, low latency, and massive connectivity. In
this article, we evaluate key challenges in wearable communications. A
cloud/edge communication architecture that integrates the cloud radio access
network, software defined network, device to device communications, and
cloud/edge technologies is presented. Computation offloading enabled by this
multi-layer communications architecture can offload computation-excessive and
latency-stringent applications to nearby devices through device to device
communications or to nearby edge nodes through cellular or other wireless
technologies. Critical issues faced by wearable communications such as short
battery life, limited computing capability, and stringent latency can be
greatly alleviated by this cloud/edge architecture. Together with the presented
architecture, current transmission and networking technologies, including
non-orthogonal multiple access, mobile edge computing, and energy harvesting,
can greatly enhance the performance of wearable communication in terms of
spectral efficiency, energy efficiency, latency, and connectivity.Comment: This work has been accepted by IEEE Vehicular Technology Magazin
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