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.

Context-Adaptive Information Security for UbiComp Environments

Abstract: Traditional computer applications expect a static execution environment. Such environments imply nonor slowlyevolving information security and privacy threat models. This assumption is no longer realistic in the Ubiquitous world scenario, where the environment around a piece of information, contained on a device or within a communications channel, is frequently changing. Thus, the information contained in the Ubiquitous world is exposed to varying threat models throughout its lifetime. Users expect high degree of information availability anytime and anywhere as needed, leading to serious security and privacy risks and access control problems.

A value-added IoT service for cellular networks using federated learning

Abstract: The number of Internet-of-Things (IoT) devices is expected to reach 64 billion by 2025. These IoT devices will mostly use cellular networks for transferring a huge amount of IoT data to the cloud for machine learning (ML) based forecasting. Keeping in view a large number of application scenarios for highly resource constraint IoT devices connected with the cellular networks, we propose a value-added IoT service (VAIS) for the cellular network operators based on the federated learning (FL) paradigm. Through simulation experiments, we show, for real air quality data and specific ML models, the proposed VAIS reduces the backhaul data by 70× and requires less energy than its equivalent cloud-based conventional approach, however, with a slight increase in communication time. From the insights we gained, we believe that a properly designed VAIS would efficiently utilize network resources, not only reduce management for IoT users but also the operating costs for cellular operators, and encourage IoT applications on limited backhaul cellular networks.

Turing Switches – Turing machines for all-optical Internet routing

Abstract: This is an EPSRC responsive mode Proposal to carry out basic long term research into the architectures for programmable all-optical Internet routers. We are revisiting some of the fundamental tenets of computer science to carry out this work, and so it is necessarily highly speculative. Currently, the processing elements in all-electronic routers are typically fairly conventional von-Neumann architecture computers with processors that have large, complex instruction sets (even RISC is relatively complex compared with the actual requirements for packet processing) and Random Access Memory. As the need for speed increases, first this architecture (see Nick McKeown’s excellent talk in reference [6]), and then the classical computing hardware components, and finally, electronics cease to be able to keep up. At this time, optical device technology is making great strides, and we see the availability of gates, as well as a plethora of invention in providing buffering mechanisms. However, a critical problem we foresee is the ability to re-program devices for different packet processing functions such as classification and scheduling. This proposal is aimed at researching one direction for adding optical domain programmability. 1 Scientific and Technological Rationale and Relevance 1.1 Purpose Turing Switching The goal of this project is to revisit basic computer science and the architectural design of computers for switching we refer to our approach as Turing Switching, as we will argue that by analogy with the original Turing Machine, a packet switch control system need not be a von Neumann architecture, or anything closely resembling it. We wish to provide a programmable optical packet switch, which has the flexibility of a software system, and the performance of an optical system. This is against current trends towards circuit (or at least label switching and wavelength or wave-band) switching. The motivation is to retain advantages of: • an evolvable network, due to programmability; • fully distributed control, with commensurate advantages of faster than RTT (round trip time) time-scale adaption to traffic and outage conditions; • continuity with Internet models and management. 1This term was recently unearthed by Tom Scott and reported in a personal communication with the proposer.

International links for research collaboration

Abstract: The European and US Research Communities have been linked for fifteen years by various communication channels. Recently, it has been decided to upgrade some of the connections to higher speed links. These links can support not only the conventional services like terminal access, file transfer, electronic mail and directory services, but also video conferencing using compressed video. Moreover the channels are being provided by different agencies with different missions and support different protocols and services. Some of the technical aspects of the links, and the policy and administrative questions which have had to be resolved, are discussed in this paper; there is particular emphasis on the UK-US link, but the discussion includes extension to other European countries. We then discuss at length the provision of video conferencing facilities over the UK-US channel, and consider how such facilities could be provided on a broader European basis.

Bridge Networking Research and Internet Standardization: Case Study on Mobile Traffic Offloading and IPv6 Transition Technologies

Abstract: The gap between networking research communities and Internet standardization organizations (SDOs) has been growing over the years, which has drawn attention from both academic and industrial sides due to its detrimental impact. The reason behind this widening gap is complex and typically beyond the mere technology ground. In this position paper we share our perspectives toward this challenge based on our hands-on experience obtained from joint projects with universities and companies. We highlight the lessons learned, covering both successful and under-performed cases, and further suggest viable solutions to bridge the gap between networking research and Internet standardization, aiming to promote and maximize the outcome of such collaborative endeavours.

I and i

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 …

Community detection in graphs

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.