Author
Jon Crowcroft
Other affiliations: Memorial University of Newfoundland, Information Technology University, Massachusetts Institute of Technology ...read more
Bio: Jon Crowcroft is an academic researcher from University of Cambridge. The author has contributed to research in topics: The Internet & Multicast. The author has an hindex of 87, co-authored 672 publications receiving 38848 citations. Previous affiliations of Jon Crowcroft include Memorial University of Newfoundland & Information Technology University.
Papers published on a yearly basis
Papers
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18 Jan 2006TL;DR: This work identifies the general scenario faced by the user of Pocket Switched Networking (PSN), and presents a set of architectural principles for PSN, and the high-level design of Haggle, an asynchronous, data-centric network architecture which addresses this environment by “raising” the API.
Abstract: Current mobile computing applications are infrastructure-centric, due to the IP-based API that these applications are written around. This causes many frustrations for end users, whose needs might be easily met with local connectivity resources but whose applications do not support this (e.g. emailing someone sitting next to you when there is no wireless access point). We identify the general scenario faced by the user of Pocket Switched Networking (PSN), and discuss why the IP-based status quo does not cope well in this environment. We present a set of architectural principles for PSN, and the high-level design of Haggle, our asynchronous, data-centric network architecture which addresses this environment by “raising” the API so that applications can provide the network with application-layer data units (ADUs) with high-level metadata concerning ADU identification, security and delivery to user-named endpoints
279 citations
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19 Mar 2007TL;DR: This paper shows how using a small label, identifying users according to their affiliation, can bring a large improvement in forwarding performance, in term of both delivery ratio and cost.
Abstract: It is widely believed that identifying communities in an ad hoc mobile communications system, such as a pocket switched network, can reduce the amount of traffic created when forwarding messages, but there has not been any empirical evidence available to support this assumption to date. In this paper, we show through use of real experimental human mobility data, how using a small label, identifying users according to their affiliation, can bring a large improvement in forwarding performance, in term of both delivery ratio and cost
275 citations
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01 Jul 1998TL;DR: This document proposes two ways of weighting TCP connections by manipulating some parameters of the protocol and presents results from simulations and prototypes to discuss how proportional fairness could be used to implement an Internet with differentiated services.
Abstract: In this document we study the application of weighted proportional fairness to data flows in the Internet. We let the users set the weights of their connections in order to maximise the utility they get from the network. When combined with a pricing scheme where connections are billed by weight and time, such a system is known to maximise the total utility of the network. Our study case is a national Web cache server connected to long distance links. We propose two ways of weighting TCP connections by manipulating some parameters of the protocol and present results from simulations and prototypes. We finally discuss how proportional fairness could be used to implement an Internet with differentiated services.
273 citations
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13 Dec 2010TL;DR: A study of the relationship between preferences for social events and geography, the first of its kind in a large metropolitan area, finds that the most effective algorithm recommends events that are popular among residents of an area, while the least effective recommendsEvents that are geographically close to the area, has interesting implications for location-based services that emphasize recommending nearby events.
Abstract: A city offers thousands of social events a day, and it is difficult for dwellers to make choices. The combination of mobile phones and recommender systems can change the way one deals with such abundance. Mobile phones with positioning technology are now widely available, making it easy for people to broadcast their whereabouts, recommender systems can now identify patterns in people’s movements in order to, for example, recommend events. To do so, the system relies on having mobile users who share their attendance at a large number of social events: cold-start users, who have no location history, cannot receive recommendations. We set out to address the mobile cold-start problem by answering the following research question: how can social events be recommended to a cold-start user based only on his home location? To answer this question, we carry out a study of the relationship between preferences for social events and geography, the first of its kind in a large metropolitan area. We sample location estimations of one million mobile phone users in Greater Boston, combine the sample with social events in the same area, and infer the social events attended by 2,519 residents. Upon this data, we test a variety of algorithms for recommending social events. We find that the most effective algorithm recommends events that are popular among residents of an area. The least effective, instead, recommends events that are geographically close to the area. This last result has interesting implications for location-based services that emphasize recommending nearby events.
267 citations
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TL;DR: In this article, the authors propose a vulnerability detection mechanism that can detect a large class of attacks through dynamic dataflow analysis and self-certifying alerts as the basis for safely sharing knowledge about worms.
Abstract: One aspect of the invention is a vulnerability detection mechanism that can detect a large class of attacks through dynamic dataflow analysis. Another aspect of the invention includes self-certifying alerts as the basis for safely sharing knowledge about worms. Another aspect of the invention is a resilient and self-organizing protocol to propagate alerts to all non-infected nodes in a timely fashion, even when under active attack during a worm outbreak. Another aspect of the invention is a system architecture that enables a large number of mutually untrusting computers to collaborate in the task of stopping a previously unknown worm, even when the worm is spreading rapidly and exploiting unknown vulnerabilities in popular software packages.
267 citations
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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.
Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …
33,785 citations
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28,685 citations
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TL;DR: In this paper, Imagined communities: Reflections on the origin and spread of nationalism are discussed. And the history of European ideas: Vol. 21, No. 5, pp. 721-722.
13,842 citations
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TL;DR: A thorough exposition of community structure, or clustering, is attempted, from the definition of the main elements of the problem, to the presentation of most methods developed, with a special focus on techniques designed by statistical physicists.
Abstract: The modern science of networks has brought significant advances to our understanding of complex systems. One of the most relevant features of graphs representing real systems is community structure, or clustering, i. e. the organization of vertices in clusters, with many edges joining vertices of the same cluster and comparatively few edges joining vertices of different clusters. Such clusters, or communities, can be considered as fairly independent compartments of a graph, playing a similar role like, e. g., the tissues or the organs in the human body. Detecting communities is of great importance in sociology, biology and computer science, disciplines where systems are often represented as graphs. This problem is very hard and not yet satisfactorily solved, despite the huge effort of a large interdisciplinary community of scientists working on it over the past few years. We will attempt a thorough exposition of the topic, from the definition of the main elements of the problem, to the presentation of most methods developed, with a special focus on techniques designed by statistical physicists, from the discussion of crucial issues like the significance of clustering and how methods should be tested and compared against each other, to the description of applications to real networks.
9,057 citations
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TL;DR: A thorough exposition of the main elements of the clustering problem can be found in this paper, with a special focus on techniques designed by statistical physicists, from the discussion of crucial issues like the significance of clustering and how methods should be tested and compared against each other, to the description of applications to real networks.
8,432 citations