Understanding collaboration in volunteer computing systems

Volunteer computing is a paradigm in which devices participating in a distributed environment share part of their resources to help others perform their activities. The effectiveness of this computing paradigm depends on the collaboration attitude adopted by the participating devices. Unfortunately for software designers it is not clear how to contribute with local resources to the shared environment without compromising resources that could then be required by the contributors. Therefore, many designers adopt a conservative position when defining the collaboration strategy to be embedded in volunteer computing applications. This position produces an underutilization of the devices’ local resources and reduces the effectiveness of these solutions. This article presents a study that helps designers understand the impact of adopting a particular collaboration attitude to contribute with local resources to the distributed shared environment. The study considers five collaboration strategies, which are analyzed in computing environments with both, abundance and scarcity of resources. The obtained results indicate that collaboration strategies based on effort-based incentives work better than those using contribution-based incentives. These results also show that the use of effort-based incentives does not jeopardize the availability of local resources for the local needs.Peer ReviewedPostprint (published version

Learning-oriented language test preparation materials: a contradiction in terms?

The impact of the use of assessment on teaching and learning is increasingly regarded as a key concern in evaluating assessment use. Realising intended forms of impact relies on more than the design of an assessment: account must also be taken of the ways in which teachers, learners and others understand the demands of the assessment and incorporate these into their practice. The measures that testing agencies take to present and explicate their tests to teachers and other stakeholders therefore play an important role in promoting intended impact and mitigating unintended, negative impact. Materials that support teachers in preparing learners to take tests (such as descriptions of the test, preparation materials and teacher training resources) play an important role in communicating the test providers’ intentions. In this study, these support materials are analysed. The selected materials, provided to teachers by Cambridge English Language Assessment, go with the Speaking component of a major international test of general English proficiency: Cambridge English: First. The study addresses how these materials might embody or reflect learning-oriented assessment principles of task authenticity, learner engagement and feedback within a coherent systemic theory of action, reconciling formative and summative assessment functions to the benefit of learning

Preparing Higher Education Tutors for Delivering Online Courses

This paper identifies that academic staff need to be suitably prepared to deliver wholly online courses, and outlines the steps taken towards achieving this, at one Higher Education institution in the UK. E-learning, whether partially (blended) or wholly online, is not simply about the technology, but also requires an understanding of the pedagogical considerations, and the skills that are needed, to effectively facilitate them. Through the use of a formal questionnaire, and collation of informal comments made on a social network, evaluation is made of a staff development course designed specifically to promote effective facilitation of high quality online courses. The results determined that the course is fit for purpose and achieves its aims. Future cohorts are already over-subscribed as a result of positive commentary by participants. Further developments will be made, based upon constructive feedback by participants. Whilst possibly not unique, this course demonstrates action being taken in an educational institution to recognise that effective online delivery requires specific knowledge and skills that are different from those used in the traditional classroom

Peer to Peer Information Retrieval: An Overview

Peer-to-peer technology is widely used for file sharing. In the past decade a number of prototype peer-to-peer information retrieval systems have been developed. Unfortunately, none of these have seen widespread real- world adoption and thus, in contrast with file sharing, information retrieval is still dominated by centralised solutions. In this paper we provide an overview of the key challenges for peer-to-peer information retrieval and the work done so far. We want to stimulate and inspire further research to overcome these challenges. This will open the door to the development and large-scale deployment of real-world peer-to-peer information retrieval systems that rival existing centralised client-server solutions in terms of scalability, performance, user satisfaction and freedom