In this paper we study the population dynamics and resource usage optimization of a P2P file sharing system, where the availability of the requested file is not guaranteed. We study the system first by a deterministic fluid model and then by a more detailed Markov chain analysis that allows estimating the life time of the system. In addition, the underlying topology of the network is modelled b...

Estimation of individual treatment effect in observational data is complicated due to the challenges of confounding and selection bias. A useful inferential framework to address this is the counterfactual (potential outcomes) model which takes the hypothetical stance of asking what if an individual had received both treatments. Making use of random forests (RF) within the counterfactual framewo...

A software usage models describes the prospective use of a program in its intended environment and allows the generation of random test cases leading to unbiased estimates of the failure risk, i.e., the expected loss by program failure. We concentrate on usage models of Markov type and show that by suitable changes of the probabilities of state transitions during test, the precision of the risk...

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We are presenting a tool for collecting and analysing computer usage data. The observed data are locally used by the user to self-monitor and self-reflect her behaviour, decontrolling the data for personalisation of information environments only with her consent. 1

A core goal of librarians is to maximize usage of the content to which their libraries subscribe. Webscale or resource discovery systems offer a single search box for library users to access subscribed content. This article examines usage data at the University of Huddersfield to show how resource discovery has helped to increase the usage of publisher content, which has been made available to ...

MIS researchers have developed a number of models for studying the software utilization choices of end users. In this paper, we focus on one of these, the Task-Technology fit model. We explore the addition of various personal characteristic constructs, especially Computer Self-Efficacy and Experience.

In this paper, we present selected findings from our usage analysis of an online English Language Teaching (ELT) workbook. We focus on how teachers assign activities and how learners complete them.

To determine helicopter component retirement intervals, it is common for fatigue engineers to utilize Miner’s rule for cumulative damage. Time consuming Monte Carlo simulations are considered the state of the art method for determining reliability in the presence of load variations. However, a new set of methods employed on a recent AHS fatigue reliability round robin problem provide an indicat...

All undergraduate and postgraduate students of the Hellenic Open University (HOU) attend courses at a distance. The lack of a live academic community is reported by many as a drawback in their studies. Systematic exploitation of new communication and collaboration technologies is desirable in HOU but cannot be imposed universally as the average student’s IT competence level is relatively low. I...