This paper discusses the challenges in computer systems research posed by the emerging field of pervasive computing. It first examines the relationship of this new field to its predecessors: distributed systems and mobile computing. It then identifies four new research thrusts: effective use

Key establishment in sensor networks is a challenging problem because asymmetric key cryptosystems are unsuitable for use in resource constrained sensor nodes, and also because the nodes could be physically compromised by an adversary. We present three new mechanisms for key establishment using

fic web site and enter their current location and destination. Although this is a powerful capability, it nonetheless requires the user to remember to check in a timely manner to adjust their route or leave earlier than forecast and to enter mundane data into the user interface. In ubiquitous computing, an autonomous agent would constantly be checking the user's current location (available from GPS or in-building wireless infrastructure) and their calendar to determine if an adjustment in schedule should be made. If traffic conditions warrant it, the user can be signaled and their PDA can show a brief reminder with the minutes left before they should head off. Another example uses a biologist in a laboratory that would like to record all the steps in their experimental protocol so that others can faithfully reproduce them. Traditional computing would provide the biologist with a PDA or laptop in which to enter each step but requiring the biologist to interrupt the flow of their work to

nodes. DSNs may be deployed in hostile areas where communication is monitored and nodes are subject to capture and surreptitious use by an adversary. Hence DSNs require cryptographic protection of communications, sensorcapture detection, key revocation and sensor disabling. In this paper, we present a

the key elements of the emergent technology of “Smart Dust ” and outline the research challenges they present to the mobile networking and systems community, which must provide coherent connectivity to large numbers of mobile network nodes co-located within a small volume.

expectations of end-to-end connectivity and node resources. The architecture operates as an overlay above the transport layers of the networks it interconnects, and provides key services such as in-network data storage and retransmission, interoperable naming, authenticated forwarding and a coarse

Reliability at massive scale is one of the biggest challenges we face at Amazon.com, one of the largest e-commerce operations in the world; even the slightest outage has significant financial consequences and impacts customer trust. The Amazon.com platform, which provides services for many web

Abstract. The PASCAL Visual Object Classes Challenge ran from February to March 2005. The goal of the challenge was to recognize objects from a number of visual object classes in realistic scenes (i.e. not pre-segmented objects). Four object classes were selected: motorbikes, bicycles, cars

... is a benchmark in visual object category recognition and detection, providing the vision and machine learning communities with a standard dataset of images and annotation, and standard evaluation procedures. Organised annually from 2005 to present, the challenge and its associated dataset has

In this paper we analyse the well known Needham-Schroeder Public-Key Protocol using FDR, a refinement checker for CSP. We use FDR to discover an attack upon the protocol, which allows an intruder to impersonate another agent. We adapt the protocol, and then use FDR to show that the new protocol