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Broadband network performance is multi-faceted: it varies by ISP, by content source, by household connection, and by time-of-day. Daily or monthly averages, as published by content providers such as Netflix and Google, do not convey the full picture. In this paper we leverage M-Lab, the world's largest open measurement platform, to characterize broadband performance across Australian households. Our...
The recently proposed concept of Elastic Optical Networks (EON) is expected to largely improve optical network resource utilization due to the possibility to divide the optical spectrum into relatively narrow segments called slices. In turn, the increasing position of numerous IT solutions in the modern world as well as the growth of network traffic trigger the need to develop robust and cost-efficient...
Secrecy capacity is the widely-used metric to evaluate the capability of wireless channels in delivering messages with the assurance of perfect security as well as reliability. However, with the proliferation and diversification of wireless services, there have been urgent needs in fine-grained and decoupled security metrics towards future mobile communications. In this paper, we propose a statistical...
Live virtual machine migration has become a core system management tool to achieve load balancing and power saving among different servers. The recent studies mainly focus on the performance improvement for live VM migration. However, there has been little attention on the migration's impact on VMs co-located both source and destination servers during the migration. The impact, which is mainly caused...
Bandwidth allocation in spectrum-congested wire- less content delivery networks should be performed based on the user's Quality of Experience (QoE). The relationship between QoE and network QoS is context- and user-dependent. We show that modeling the user's QoE introduces additional complexity to the bandwidth allocation problem. While recent research has proposed various ways in which complexity...
Users who retrieve information across disadvantaged networks need to do so in such a way as to minimize network performance impact while maximizing the usefulness and quality of information (QOI) received. Taking advantage of features from all three network genres (telecommunication, information, and social) will enable this balancing act. These users also need to interact using unstructured, ad-hoc...
Wireless intelligent transport systems based on Car-to-X communication technology are about to enter the mass market in upcoming years. Thereby, efficient and reliable security systems are a core point of concern in system design. Currently regarded digital signature schemes using pseudonym certificates can introduce significant overhead into the highly bandwidth restricted system. Thus, mechanisms...
In this digital era, Internet has become the most widely used media of communication. Numerous critical services like e-commerce, social media, online banking are based on the Internet, so non-availability of Internet may lead of financial, social and legal implications. DDoS attacks are the most serious attack that hampers the availability of Internet. Their major aim is to deny the services of the...
Numerous research groups and other organizations collect data from popular data sources such as online social networks. This leads to the problem of data islands, wherein all this data is isolated and lying idly, without any use to the community at large. Using existing centralized solutions such as Drop box to replicate data to all interested parties is prohibitively costly, given the large size...
The Internet of Things (IoT) has a significant effect on the evolution of modern Information and Communication Technology. It reshapes the traditional network infrastructures with novel hardware and software technologies. In this work we analyse the IoT platforms from the communication architecture point of view and we evaluate the effects of the communication anomalies on different edges of the data...
A detailed understanding of HPC application's resource needs and their complex interactions with each other and HPC platform resources is critical to achieving scalability and performance. Such understanding has been difficult to achieve because typical application profiling tools do not capture the behaviors of codes under the potentially wide spectrum of actual production conditions and because...
In this work, we present the characterization of a set of scientific kernels which are representative of the behavior of fundamental and applied physics applications across a wide range of fields. We collect performance attributes in the form of micro-operation mix and off-chip memory bandwidth measurements for these kernels. Using these measurements, we use two clustering methodologies to show which...
To understand better what happens when video streaming takes place, this paper introduces a framework to simulate a real-time video streaming over wireless channels. The system is divided into many modules and is simulated with different tools. DUMMYNET is used for the network simulator while FFMPEG is for coder/encoder and sender/receiver module. The video quality is measured by spatial (SSIM and...
This paper aims to investigate the resource allocation problem in a relay-assisted OFDMA cognitive radio (CR) system. Different from conventional CR resource allocation problems, a joint bandwidth and power optimization framework using the bandwidth-power product metric is proposed. Besides, rate requirement of the secondary system is satisfied and interference power at the primary receiver is limited...
In Mobile ad-hoc networks (MANET), QoS protocols includes the intermediate nodes which have sufficient resources along the route, from source to destination. Nodes may turn non cooperative when they are running with shortage of resources, which weakens the effectiveness of the protocol. The proposed model (Uncertain Rule-based Fuzzy Logic QoS Trust Model in MANETs -FQTM) selects the nodes which are...
This document presents cross-polarisation ratios (XPRs) of propagation paths measured in indoor 70 GHz channels. To the best of authors' knowledge, very few polarisation measurement results of millimetre wave channels have been reported. The channel measurements are performed in large indoor short-range scenarios such as offices, a shopping mall, and a railway station. Due to the large measurement...
A sinusoidally corrugated periodic Bull's-Eye leaky wave antenna operating at 77 GHz is numerically and experimentally analyzed. Gain enhancement and bandwidth narrowing are observed as the number of periods is increased. Numerical and experimental results are in good agreement for the fabricated 20 period sinusoidal structure, showing a 28.9 dB gain with less than −20 dB side lobe level and a very...
The large bandwidth of ultra wideband (UWB) makes it attractive in high speed transmission applications. However, the possibility of frequency selectivity of the channel is high due to this bandwidth. Channel characterization is important to study the behavior of the channel. The ground reflection effects are important parameters affecting the ultra wideband channel. In this paper, based on outdoor...
Heterogeneous networks principally composed of macro-cells overlaid with small cells (e.g., Femtocells, pico-cells, and relays) can potentially improve the coverage and capacity of existing cellular networks and satisfy the growing demands of data throughput. In Het Nets, small cells play a key role in offloading user data traffic from congested macro-cells and extending the limited coverage of macro-cells...
Recent literature has suggested the benefits of integrating licensed radio and cognitive radio into a hybrid cooperative communication system. The fundamental properties of such hybrid systems, however, have not been thoroughly investigated. This paper studies the hybrid cognitive Gaussian relay channel (HCGRC), which uses licensed radio resource (RR) and cognitive/unlicensed RR for forward and relay...
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