Modern peer-to-peer file sharing systems rely heavily on the willingness of users to distribute files to others. A selfish user can choose to download a file and consume resources without uploading in return. This form of free-riding plagues all currently deployed peer-to-peer systems. We present a novel protocol for a BitTorrent-like system (i.e., one in which only one file is being shared) th...

This paper considers the problem of adapting the BitTorrent protocol for on-demand streaming. BitTorrent is a popular peer-to-peer file sharing protocol that efficiently accommodates a large number of requests for file downloads. Two components of the protocol, namely the rarest-first piece selection policy and the tit-for-tat algorithm for peer selection, are acknowledged to contribute toward ...

The complexity of Information Technology (IT) systems is steadily increasing. System complexity has been recognised as the main obstacle to further advance of IT and has recently raised energy management issues. Control techniques have been proposed and successfully applied to design Autonomic Computing systems, i.e., systems able to manage themselves trading-off system performance with energy ...

Textbooks play a pivotal role in language learning classrooms. The problem is, among a wide range of textbooks available, which one is more appropriate for a specific classroom and a group of learners. In order to evaluate ELT textbooks, theorists and writers have offered different kinds of evaluative frameworks based on a number of principles and criteria. This study evaluates one example of s...

We construct a parametrization of the deep-inelastic structure function of the proton F2(x,Q ) based on all available experimental information from charged lepton deep-inelastic scattering experiments. The parametrization effectively provides a bias-free determination of the probability measure in the space of structure functions, which retains information on experimental errors and correlation...

The Macintosh OS X operating system is built to interface with the HFS+ file system. Assuming that allocations and disk I/O can be detected by monitoring the internal clock and noting any significant slowdown, we attempted to discover block size, any effects of prefetching, the file cache size, and the number of direct pointers in the HFS+ inode. Our tests were met with unfortunate amounts of n...

We report the results of our radial-velocity monitoring of spectroscopic binary systems in a sample of X-ray sources from the ROSAT All Sky Survey south of the Taurus-Auriga star-forming region. The original sample of ∼120 sources by Neuhäuser et al. was selected on the basis of their X-ray properties and the visual magnitude of the nearest optical counterpart, in such a way as to promote the i...

Understanding the role that social cues have on interpersonal choice, and their susceptibility to contextual effects, is of core importance to models of social decision-making. Language, on the other hand, is one of the main means of communication during social interactions in our culture. The present experiments tested whether positive and negative linguistic descriptions of alleged partners i...

In this paper, we present a study of low-level disk access patterns for three workloads for a variety of file systems. While there has been a great deal of work on disk architectures, there has been very little work measuring actual low-level disk access. We have extended previous work to also consider different file systems to examine their effect on the workload. The analysis is done based on...