Byzantine faults in a peer-to-peer (P2P) system are resulted from adversarial and inconsistent peer behaviors. Malicious peers can disrupt the routing functions in peer joining and lookup services. Byzantine attackers may collude with each other to paralyze the entire P2P network operations. We discover a new class of DHT-based overlay networks, called inverse de Bruijn (IDB) graph, to enable m...

Several challenges come to fore while realizing collaborations among independent administrative domains in a distributed setup. Interoperability of access control models, deployed in respective collaborating domains, is one such challenge. Collaborating domains may have heterogeneous types of access control models that need to be interoperable in order to accommodate each other’s collaborating ...

OBJECTIVE To assess the cost effectiveness of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers in patients admitted to hospital. DESIGN Cost effectiveness analysis carried out alongside the pressure relieving support surfaces (PRESSURE) trial; a multicentre UK based pragmatic randomised controlled trial. SETTING 11 hospitals i...

Overlay networks have emerged as a powerful paradigm to realise a large range of distributed services. However, as the number of overlays grows and the systems that use them become more interconnected, overlays must increasingly co-exist within the same infrastructure. When this happens, overlays have to compete for limited resources, which causes negative interferences. This paper takes an opp...

We are experiencing a revolution in the wireless technology and mobile phone networks as they are becoming increasingly ubiquitous. On the other hand, there is another trend, gaining extreme popularity over the traditional wired Internet: Peer-to-Peer (P2P) networking. Specifically, Distributed Hash Table (DHT) based Structured P2P overlay networks are capable to facilitate information storage ...

Objective To assess the cost effectiveness of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers in patients admitted to hospital. Design Cost effectiveness analysis carried out alongside the pressure relieving support surfaces (PRESSURE) trial; a multicentre UK based pragmatic randomised controlled trial. Setting 11 hospitals in si...

A simple reading test that can be undertaken by disabled readers is described. The test is suitable for use in the optometric clinic, taking less than 2 minutes to administer per passage. Test-retest scores are acceptably reliable. The test reveals increases in the speed of reading when coloured overlays are used both (1) in children who have made long-term use of coloured overlays for reading,...