Browsing University of Hertfordshire by Author "Christianson, B."

Now showing items 1-20 of 144

    • Academic dress in the University of Hertfordshire 

      Christianson, B. (University of Hertfordshire, 2006)
      In accordance with tradition, our academic dress consists of a gown, a cap, and a hood. The black gown and square cap familiar to all readers of the Beano had evolved into pretty much their present form in England by the ...

    • An Adaptive Access Control Model for Medical Data in Wireless Sensor Networks 

      Maw, Htoo; Xiao, Hannan; Christianson, B. (Institute of Electrical and Electronics Engineers (IEEE), 2013-10)
      Wireless Sensor Networks (WSNs) have recently attracted a lot of interest in the research community. The security mechanism with large overhead of computation and communication, are infeasible to apply in WSNs due to many ...

    • An Adaptive Access Control Model with Privileges Overriding and Behaviour Monitoring in Wireless Sensor Networks 

      Maw, Htoo Aung; Xiao, Hannan; Christianson, B. (ACM Press, 2012-10)
      Wireless Sensor Networks (WSNs) have attracted a lot of interest in the research community because of their wide range of applications. Due to the distributed nature of WSNs and their deployment in remote areas, these ...

    • Analysis of DoS Attacks at MAC Layer in Mobile Adhoc Networks 

      Alocious, Chaminda; Xiao, Hannan; Christianson, B. (Institute of Electrical and Electronics Engineers (IEEE), 2015-10-05)
      —Wireless network security has received tremendous attention due to the vulnerabilities exposed in the open communication medium. The most common wireless Medium Access Control (MAC) protocol is IEEE 802.11, which assumes ...

    • Anonymous authentication 

      Das Chowdhury, P.; Malcolm, J.; Christianson, B. (2006)
      The contribution of this paper is a mechanism which links authentication to audit using weak identities and takes identity out of the trust management envelope. Although our protocol supports weaker versions of anonymity ...

    • Anonymous Context Based Role Activation Mechanism 

      Das Chowdhury, P.; Christianson, B.; Malcolm, J. (2005)
      Privacy is not an explicit goal of traditional authorisation mechanisms. The contribution of this paper is an authorisation mechanism which takes identity out of the trust management envelope. Our protocol supports weak ...

    • Application of automatic differentiation to race car performance optimisation 

      Christianson, B.; Casanova, D.; Sharp, R.S.; Final, M.; Symonds, P. (Springer Nature, 2002)
      A formal method for the evaluation of the minimum time vehicle manoeuvre is described. The problem is treated as one of optimal control and is solved using a direct transcription method. The resulting nonlinear programming ...

    • Artists as HRI pioneers : A creative approach to developing novel interactions for living with robots 

      Lehmann, H.; Walters, M.L.; Dumitriu, A.; May, A.; Koay, K.L.; Sàez-Pons, J.; Syrdal, D.S.; Wood, L.J.; Saunders, Joe; Burke, N.; Duque-Garcia, I.; Christianson, B.; Dautenhahn, K. (Springer Nature, 2013-12)
      In this article we present a long-term, continuous human-robot cohabitation experiment, which involved two professional artists, whose artistic work explores the boundary between science and society. The artists lived in ...

    • Arty-facts : The role of performance in the "conventional" PhD 

      Christianson, B.; Adams, Steven (UK Council for Graduate Education, 2011)
      Much has been written about various changes made to doctoral regulations in order to accommodate professional and practice-based doctoral research programmes. These changes are sometimes disparaged by those in more established ...

    • Associative Memories with Small World Connectivity 

      Davey, N.; Calcraft, L.; Christianson, B.; Adams, R.G. (Springer Nature, 2005)
      In this paper we report experiments designed to find the relationship between the different parameters of sparsely connected networks of perceptrons with small world connectivity patterns, acting as associative memories.

    • Auditable Anonymous Delegation 

      Christianson, B.; Das Chowdhury, P.; Malcolm, J. (2005)
      The contribution of this paper is an alternative mechanism for delegation, whereby users can share their credentials in such a way that it is difficult for the delegatee to re-use credentials of the delegator. An auditor ...

    • Authentication v Certification 

      Low, M.R.; Christianson, B. (University of Hertfordshire, 1995)
      Authentication servers and certification authorities are usually viewed simply as alternative ways of providing the same service. In this paper we show that the differences in the natures of these two approaches are more ...

    • Automatic Differentiation of Algorithms 

      Bartholomew-Biggs, M.; Brown, S.; Christianson, B.; Dixon, L. (2000)
      We introduce the basic notions of Automatic Differentiation, describe some extensions which are of interest in the context of nonlinear optimization and give some illustrative examples.

    • Automatic differentiation of computer programs in a parallel computing environment 

      Brown, S.; Christianson, B. (Computational Mechanics, 1997)
      This paper gives an introduction to a number of methods collectively known as Automatic Differentiation (AD). AD is the systematic application of the rules of calculus to computer programs yielding, as output, programs ...

    • Automatic first- and second-order adjoints for truncated Newton 

      Naumann, Uwe; Maier, M.; Riehme, Jan; Christianson, B. (Polskie Towarzystwo Informatyczne, 2007)
      The analysis and modification of numerical programs in the context of generating and optimizing adjoint code automatically probably ranges among the technically and theoretically most challenging source transformation ...

    • Automatic Hessians by reverse accumulation 

      Christianson, B. (1992)
      Let n be the number of independent variables of a function f, and let W and S respectively be the time and space bounds for the joint evaluation of {f, f} using automatic differentiation with reverse accumulation. In this ...

    • Automatic Propagation of Uncertainties 

      Christianson, B.; Cox, M. (2006)
      Motivated by problems in metrology, we consider a numerical evaluation program y = f(x) as a model for a measurement process. We use a probability density function to represent the uncertainties in the inputs x and examine ...

    • Binding bit patterns to real world entities 

      Christianson, B.; Malcolm, J. (1998)
      Public key cryptography is often used to verify the integrity of a piece of data, or more generally to ensure that operations which modify the data have been requested and carried out by principals who are authorized to ...

    • Binding bit patterns to real world entities 

      Christianson, B.; Malcolm, J. (University of Hertfordshire, 1997)
      Public key cryptography is often used to verify the integrity of a piece of data, or more generally to ensure that operations which modify the data have been requested and carried out by principles who are authorized to ...

    • A Candour-based Trust and Reputation Management System for Mobile Ad Hoc Networks 

      Chiejina, Eric; Xiao, Hannan; Christianson, B. (University of York, 2013)
      The decentralized administrative controlled-nature of mobile ad hoc networks (MANETs) presents security vulnerabilities which can lead to attacks such as malicious modification of packets. To enhance security in MANETs, ...