Beyond Node Degree: Evaluating AS Topology Models

This is the accepted version of 'Beyond Node Degree: Evaluating AS Topology Models', archived originally at arXiv:0807.2023v1 [cs.NI] 13 July 2008.Many models have been proposed to generate Internet Autonomous System (AS) topologies, most of which make structural assumptions about the AS graph. In this paper we compare AS topology generation models with several observed AS topologies. In contrast to most previous works, we avoid making assumptions about which topological properties are important to characterize the AS topology. Our analysis shows that, although matching degree-based properties, the existing AS topology generation models fail to capture the complexity of the local interconnection structure between ASs. Furthermore, we use BGP data from multiple vantage points to show that additional measurement locations significantly affect local structure properties, such as clustering and node centrality. Degree-based properties, however, are not notably affected by additional measurements locations. These observations are particularly valid in the core. The shortcomings of AS topology generation models stems from an underestimation of the complexity of the connectivity in the core caused by inappropriate use of BGP data

Anatomy of the Third-Party Web Tracking Ecosystem

The presence of third-party tracking on websites has become customary. However, our understanding of the third-party ecosystem is still very rudimentary. We examine third-party trackers from a geographical perspective, observing the third-party tracking ecosystem from 29 countries across the globe. When examining the data by region (North America, South America, Europe, East Asia, Middle East, and Oceania), we observe significant geographical variation between regions and countries within regions. We find trackers that focus on specific regions and countries, and some that are hosted in countries outside their expected target tracking domain. Given the differences in regulatory regimes between jurisdictions, we believe this analysis sheds light on the geographical properties of this ecosystem and on the problems that these may pose to our ability to track and manage the different data silos that now store personal data about us all

Understanding food consumption lifecycles using wearable cameras

Application of design in HCI is a common approach to engendering behavioural change to address important challenges such as sustainability. Encouraging such change requires an understanding of current motivations and behaviours in the domain in question. In this paper, we describe use of wearable cameras to study motivations and behaviours around food consumption by focusing on two contrasting cultures, Malaysia and the UK. Our findings highlight the potential of wearable cameras to enhance knowledge of food consumption practices and identify where and how some digital interventions might be appropriate to change food behaviour. This includes appealing to people’s motivations behind food consumption and capitalising on existing practices such as gifting of food and social meals. We propose a food consumption lifecycle as a framework to understand and design human–food interaction. The use of wearable cameras enabled us to capture a high-level overview of spatially distributed food-related practices and understand food behaviours in greater depth.This work was co-funded by Horizon Digital Economy Research Institute, UK, and Crops for the Future, Malaysia.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00779-015-0871-

Inter-social-networking: Accounting for multiple identities

We argue that the current approaches to online social networking give rise to numerous challenges regarding the management of the multiple facets of people’s digital identities within and around social networking sites (SNS). We propose an architecture for enabling people to better manage their SNS identities that is informed by the way the core Internet protocols developed to support interoperation of proprietary network protocols, and based on the idea of Separation of Concerns [1]. This does not require modification of existing services but is predicated on providing a connecting layer over them, both as a mechanism to address problems of privacy and identity, and to create opportunities to open up online social networking to a much richer set of possible interactions and applications.This work is supported by Horizon Digital Economy Research, RCUK grant EP/G065802/1; and by CREATe, the Centre for Copyright and New Business Models, RCUK grant AH/K000179/1. Packages and source are available under open source licenses at github.com/CREATe-centre/.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/978-3-319-20367-6_2

Exploring Interpretations of Data from the Internet of Things in the Home

The ‘Internet of Things’ (IoT) can be expected to radically increase the amount of potentially sensitive data gathered in our homes. This study explores the social implications of the presentation of data that could be collected within the household. In particular, it focuses on how ambiguities in these data, combined with existing interpersonal relationships, could influence social dynamics. Thirty-five participants were each presented with three separate household scenarios, involving ambiguous data that were collected and presented via near-future IoT technologies. Each participant was asked to respond to a series of open and closed questions about how they would interpret the data, how they would react to it and their general opinions of the technologies presented. Through qualitative and quantitative analysis of their responses, we contribute an understanding of how people interpret information about those around them. We find a common willingness to make inferences based on ambiguities within the data, even when participants are aware of the limitations of their understanding. We also find that sharing data produced via tagging of everyday objects raises a high level of privacy concern, and that, in a somewhat incoherent stance, users are more comfortable in sharing data publicly than in a targeted fashion with commercial organizations. Our findings also suggest that the age of the target user group has a greater effect on ease of use judgements than the nature of the technology, and we find some evidence that user’s interpretations can be biased by an individual’s age

Li depletion in solar analogues with exoplanets: Extending the sample

We want to study the effects of the formation of planets and planetary systems on the atmospheric Li abundance of planet host stars. In this work we present new determinations of lithium abundances for 326 Main Sequence stars with and without planets in the T$_\mathrm{eff}$ range 5600-5900 K. 277 stars come from the HARPS sample, the remaining targets have been observed with a variety of high resolution spectrographs. We confirm significant differences in the Li distribution of solar twins (T$_\mathrm{eff}$ = T$_{\odot} \pm$ 80 K, log g = log g$_{\odot}$ $\pm$ 0.2 and [Fe/H] = [Fe/H]$_{\odot} \pm$ 0.2): the full sample of planet host stars (22) shows Li average values lower than "single" stars with no detected planets (60). If we focus in subsamples with narrower ranges in metallicity and age, we observe indications of a similar result though it is not so clear for some of the studied subsamples. Furthermore, we compare the observed spectra of several couples of stars with very similar parameters which show different Li abundances up to 1.6 dex. Therefore we show that neither age, nor mass nor metallicity of a parent star is the only responsible for enhanced Li depletion in solar analogues. We conclude that another variable must account for that difference and suggest that this could be the presence of planets which causes additional rotationally induced mixing in the external layers of planet host stars. Moreover, we find indications that the amount of depletion of Li in planet host solar-type stars is higher when the planets are more massive than Jupiter.Comment: 16 pages, accepted for publication in A&

FLICK: developing and running application-specific network services

Data centre networks are increasingly programmable, with application-specific network services proliferating, from custom load-balancers to middleboxes providing caching and aggregation. Developers must currently implement these services using traditional low-level APIs, which neither support natural operations on application data nor provide efficient performance isolation. We describe FLICK, a framework for the programming and execution of application-specific network services on multi-core CPUs. Developers write network services in the FLICK language, which offers high-level processing constructs and application-relevant data types. FLICK programs are translated automatically to efficient, parallel task graphs, implemented in C++ on top of a user-space TCP stack. Task graphs have bounded resource usage at runtime, which means that the graphs of multiple services can execute concurrently without interference using cooperative scheduling. We evaluate FLICK with several services (an HTTP load-balancer, a Memcached router and a Hadoop data aggregator), showing that it achieves good performance while reducing development effort