scispace - formally typeset
Search or ask a question
Author

Jon Crowcroft

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
More filters
Proceedings ArticleDOI
09 Sep 2012
TL;DR: This work models two simple models and learns that simply recommending power users works better than random but is far from producing the best recommendations and recommends places that are closest to a user's geographic center of interest that are as accurate as, if not more accurate than, an item-based recommender's.
Abstract: Social-networking sites have started to offer tools that suggest "guests" who should be invited to user-defined social events (e.g., birthday parties, networking events). The problem of how to recommend people to events is similar to the more traditional (recommender system) problem of how to recommend events (items) to people (users). Yet, upon Foursquare data of "who visits what" in the city of London, we show that a state-of-the-art recommender system does not perform well -mainly because of data sparsity. To fix this problem, we add domain knowledge to the recommendation process. From the complex system literature in human mobility, we learn two insights: 1) there are special individuals (often called power users) who visit many places; and 2) individuals go to a venue not only because they like it but also because they are close-by. We model these insights into two simple models and learn that: 1) simply recommending power users works better than random but is far from producing the best recommendations; 2) an item-based recommender system produces accurate recommendations; and 3) recommending places that are closest to a user's geographic center of interest produces recommendations that are as accurate as, if not more accurate than, item-based recommender's. This last result has practical implications as it offers guidelines for designing location-based recommender systems and for partly addressing cold-start situations.

25 citations

Proceedings ArticleDOI
15 Jun 2010
TL;DR: In this article, the authors re-assert the importance of large-scale datasets in communication network design, and claim that this could impact fundamental studies in other academic disciplines, and argue that planet-scale mobility measurements can help to save the world.
Abstract: Research into, and design and construction of mobile systems and algorithms requires access to large-scale mobility data. Unfortunately, the research community lacks such data. For instance, the largest available human contact traces contain only 100 nodes with very sparse connectivity, limited by experimental logistics. In this paper we pose a challenge to the community: how can we collect mobility data from billions of human participants? We re-assert the importance of large-scale datasets in communication network design, and claim that this could impact fundamental studies in other academic disciplines. In effect, we argue that planet-scale mobility measurements can help to save the world. For example, through understanding large-scale human mobility, we can track and model and contain the spread of epidemics of various kinds.

25 citations

Journal ArticleDOI
TL;DR: In the 'Management of Multiservice Networks' project, BT and its academic partners are developing key middleware components required to support application-layer active networking.
Abstract: Future requirements for a broadband multimedia network are likely to be very different from those today. Three key changes are identified — rapid introduction of new services, dynamic customisation of services by clients, and minimal management overhead. Application-layer active networking, perhaps the most pragmatic and immediately realisable active network proposal, is a potential solution to all three. In the ‘Management of Multiservice Networks‘ project, BT and its academic partners are developing key middleware components required to support application-layer active networking.

24 citations

Journal ArticleDOI
TL;DR: The main features of Bluetooth Mesh and 6BLEMesh are presented, and their performance characteristics and trade-offs are investigated.
Abstract: Bluetooth Low Energy (BLE) mesh networking is an emerging technology domain that promises an important role in the Internet of Things. Significant market opportunities for BLE mesh networking have motivated the recent development of two different BLE mesh networking standards, Bluetooth Mesh and 6BLEMesh, produced by the Bluetooth SIG and IETF, respectively. These two standards follow different technical approaches. In this article, we present the main features of Bluetooth Mesh and 6BLEMesh, and investigate their performance characteristics and trade-offs.

24 citations


Cited by
More filters
Journal ArticleDOI

[...]

08 Dec 2001-BMJ
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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