ISP-friendly Peer-assisted On-demand Streaming of Long Duration Content in BBC iPlayer

In search of scalable solutions, CDNs are exploring P2P support. However, the benefits of peer assistance can be limited by various obstacle factors such as ISP friendliness - requiring peers to be within the same ISP, bitrate stratification - the need to match peers with others needing similar bitrate, and partial participation - some peers choosing not to redistribute content. This work relates potential gains from peer assistance to the average number of users in a swarm, its capacity, and empirically studies the effects of these obstacle factors at scale, using a month-long trace of over 2 million users in London accessing BBC shows online. Results indicate that even when P2P swarms are localised within ISPs, up to 88% of traffic can be saved. Surprisingly, bitrate stratification results in 2 large sub-swarms and does not significantly affect savings. However, partial participation, and the need for a minimum swarm size do affect gains. We investigate improvements to gain from increasing content availability through two well-studied techniques: content bundling - combining multiple items to increase availability, and historical caching of previously watched items. Bundling proves ineffective as increased server traffic from larger bundles outweighs benefits of availability, but simple caching can considerably boost traffic gains from peer assistance.Comment: In Proceedings of IEEE INFOCOM 201

Operating theatre modelling: integrating social measures

Hospital resource modelling literature is primarily focussed on productivity and efficiency measures. In this paper, our focus is on the alignment of the most valuable revenue factor, the operating room (OR) with the most valuable cost factor, the staff. When aligning these economic and social decisions, respectively, into one sustainable model, simulation results justify the integration of these factors. This research shows that integrating staff decisions and OR decisions results in better solutions for both entities. A discrete event simulation approach is used as a performance test to evaluate an integrated and an iterative model. Experimental analysis show how our integrated approach can benefit the alignment of the planning of the human resources as well as the planning of the capacity of the OR based on both economic related metrics (lead time, overtime, number of patients rejected) and social related metrics (personnel preferences, aversions, roster quality)

Interpreting infrastructure: Defining user value for digital financial intermediaries.

The 3DaRoC project is exploring digital connectivity and peer-to-peer relationships in financial services. In the light of the near collapse of the UK and world financial sector, understanding and innovating new and more sustainable approaches to financial services is now a critical topic. At the same time, the increasing penetration and take-up of robust high-speed networks, dependable peerto- peer architectures and mobile multimedia technologies offer novel platforms for offering financial services over the Internet. These new forms of digital connectivity give rise to opportunities in doing financial transactions in different ways and with radically different business models that offer the possibility of transforming the marketplace. One area in the digital economy that has had such an effect is in the ways that users access and use digital banking and payment services. The impact of the new economic models presented by these digital financial services is yet to be fully determined, but they have huge potential as disruptive innovations, with a potentially transformative effect on the way that services are offered to users. Little is understood about how technical infrastructures impact on the ways that people make sense of the financial services that they use, or on how these might be designed more effectively. 3DaRoC is exploring this space working with our partners and end users to prototype and evaluate new online, mobile, ubiquitous and tangible technologies, exploring how these services might be extended.Executive Summary: Drawing from Studies of Use - the value, use and interpretation of infrastructure in digital intermediaries to their users. The UK economy has a huge dependence on financial services, and this is increasingly based on digital platforms. Innovating new economic models around consumer financial services through the use of digital technologies is seen as increasingly important in developed economies. There are a number of drivers for this, ranging from national economic factors to the prosaic nature of enabling cheap, speedy and timely interactions for users. The potential for these new digital solutions is that they will allay an over-reliance on the traditional banking sector, which has proved itself to be unstable and risky, and we have seen a number of national policy moves to encourage growth in this sector. Partly as a result of the 2008 banking crisis, there has been an explosion in peer-to-peer financial services for non-professional consumers. These organisations act as intermediaries between users looking to trade goods or credit. However, building self-sustaining or profitable financial services within this novel space is itself fraught with commercial, regulatory, technical and social problems. This document reports on the value, use and interpretation of infrastructure in digital intermediaries to their users, describing analysis of contextual field studies carried out in two retail digital financial intermediary organisations: Zopa Limited and the Bristol Pound. It forms the second milestone document in the 3DaRoC project, developing patterns of use that have arisen on the back of the technical infrastructures in the two organisations that form cases for examination. Its purpose is to examine how the two different technical infrastructures that underpin the transactions that they support–composed of the back-office hardware and software, data structures, the networking and communications technologies used, supported consumer devices, and the user interfaces and interaction design–have provided opportunities for users to realise their financial and other needs. While we orient towards the issues of service use (and its problems), we also examine the activities and expectations of their various users. Our research has involved teams from Lancaster University examining Zopa and Brunel University focusing on the Bristol Pound over approximately a one-year period from October 2013 to October 2014. Extensive interviews, document analysis, observation of user interactions, and other methods have been employed to develop the process analyses of the firms presented here. This report comprises of three key sections: descriptions of the user demographics for Zopa and the Bristol Pound, a discussion about the user experience and its role in community, and an examination of the role of usage data in the development of these a products. We conclude with final analytical section drawing preliminary conclusions from the research presented.The 3DaRoC project is funded by the RCUK Digital Economy ‘Research in the Wild’ theme (grant no. EP/K012304/1)

Blockchain Inefficiency in the Bitcoin Peers Network

We investigate Bitcoin network monitoring the dynamics of blocks and transactions. We unveil that 43\% of the transactions are still not included in the Blockchain after 1h from the first time they were seen in the network and 20\% of the transactions are still not included in the Blockchain after 30 days, revealing therefore great inefficiency in the Bitcoin system. However, we observe that most of these `forgotten' transactions have low values and in terms of transferred value the system is less inefficient with 93\% of the transactions value being included into the Blockchain within 3h. The fact that a sizeable fraction of transactions is not processed timely casts serious doubts on the usability of the Bitcoin Blockchain for reliable time-stamping purposes and calls for a debate about the right systems of incentives which a peer-to-peer unintermediated system should introduce to promote efficient transaction recording.Comment: 15 pages, 8 figures, 3 table

Framing the collaborative economy - Voices of contestation

Within the context of multiple crises and change, a range of practices discussed under the umbrella term of collaborative (or sharing) economy have been gaining considerable attention. Supporters build an idealistic vision of collaborative societies. Critics have been stripping the concept of its visionary potential, questioning its revolutionary nature. In the study, these debates are brought down to the local level in search for common perceptions among the co-creators of the concept in Vienna, Austria. Towards this aim a Q study is conducted, i.e. a mixed method enabling analyses of subjective perceptions on socially contested topics. Four framings are identified: Visionary Supporters, Market Optimists, Visionary Critics, and Skeptics, each bringing their values, visions, and practical goals characteristic of different understanding of the collaborative economy. The study questions the need for building a globally-applicable definition of the concept, calls for more context-sensitivity, exploratory studies, and city-level multi-stakeholder dialogues

The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, $\lambda = g_A / g_V$, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter $a$ with a precision of $\delta a / a = 10^{-3}$ and the Fierz interference term $b$ to $\delta b = 3\times10^{-3}$ in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio $\lambda$ with a precision of $\delta \lambda / \lambda = 0.03\%$ that will allow an evaluation of $V_{ud}$ and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.Comment: Presented at PPNS201

Self-Healing Protocols for Connectivity Maintenance in Unstructured Overlays

In this paper, we discuss on the use of self-organizing protocols to improve the reliability of dynamic Peer-to-Peer (P2P) overlay networks. Two similar approaches are studied, which are based on local knowledge of the nodes' 2nd neighborhood. The first scheme is a simple protocol requiring interactions among nodes and their direct neighbors. The second scheme adds a check on the Edge Clustering Coefficient (ECC), a local measure that allows determining edges connecting different clusters in the network. The performed simulation assessment evaluates these protocols over uniform networks, clustered networks and scale-free networks. Different failure modes are considered. Results demonstrate the effectiveness of the proposal.Comment: The paper has been accepted to the journal Peer-to-Peer Networking and Applications. The final publication is available at Springer via http://dx.doi.org/10.1007/s12083-015-0384-