Why Delannoy numbers?

This article is not a research paper, but a little note on the history of combinatorics: We present here a tentative short biography of Henri Delannoy, and a survey of his most notable works. This answers to the question raised in the title, as these works are related to lattice paths enumeration, to the so-called Delannoy numbers, and were the first general way to solve Ballot-like problems. These numbers appear in probabilistic game theory, alignments of DNA sequences, tiling problems, temporal representation models, analysis of algorithms and combinatorial structures.Comment: Presented to the conference "Lattice Paths Combinatorics and Discrete Distributions" (Athens, June 5-7, 2002) and to appear in the Journal of Statistical Planning and Inference

A Survey on Continuous Time Computations

We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature

An evaluation of a teaching package constructed using a Web‐based lecture recorder

This paper describes an evaluation of a teaching package used to replace lectures in two closely related university courses on Discrete Mathematics. The package was developed using Audiograph, a Web‐based lecture recorder developed at the University of Surrey. Two groups of subjects were studied: a group of undergraduates, mostly fresh from schools, and a group of postgraduates, mostly with post‐university work experience. Although the postgraduates with their greater maturity and experience were significantly more positive in their appraisal than the undergraduates, both groups agreed on the beneficial aspects of being able to work at one's own time and pace, and being able to repeat material at will. It is clear, however, that, in the context investigated, where the lecturer was readily available, such a package can never supplant a human teacher, and that considerable effort needs to be expended in order to integrate the package into a rich learning environment

A Digital Signature Scheme for Long-Term Security

In this paper we propose a signature scheme based on two intractable problems, namely the integer factorization problem and the discrete logarithm problem for elliptic curves. It is suitable for applications requiring long-term security and provides a more efficient solution than the existing ones

Self-Evaluation Applied Mathematics 2003-2008 University of Twente

This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008