Constructing Optimal Authentication Codes with Perfect Multi-fold Secrecy

We establish a construction of optimal authentication codes achieving perfect multi-fold secrecy by means of combinatorial designs. This continues the author's work (ISIT 2009) and answers an open question posed therein. As an application, we present the first infinite class of optimal codes that provide two-fold security against spoofing attacks and at the same time perfect two- fold secrecy.Comment: 4 pages (double-column); to appear in Proc. 2010 International Zurich Seminar on Communications (IZS 2010, Zurich

Computational complexity of reconstruction and isomorphism testing for designs and line graphs

Graphs with high symmetry or regularity are the main source for experimentally hard instances of the notoriously difficult graph isomorphism problem. In this paper, we study the computational complexity of isomorphism testing for line graphs of $t$-$(v,k,\lambda)$ designs. For this class of highly regular graphs, we obtain a worst-case running time of $O(v^{\log v + O(1)})$ for bounded parameters $t,k,\lambda$. In a first step, our approach makes use of the Babai--Luks algorithm to compute canonical forms of $t$-designs. In a second step, we show that $t$-designs can be reconstructed from their line graphs in polynomial-time. The first is algebraic in nature, the second purely combinatorial. For both, profound structural knowledge in design theory is required. Our results extend earlier complexity results about isomorphism testing of graphs generated from Steiner triple systems and block designs.Comment: 12 pages; to appear in: "Journal of Combinatorial Theory, Series A

Coding Theory and Algebraic Combinatorics

This chapter introduces and elaborates on the fruitful interplay of coding theory and algebraic combinatorics, with most of the focus on the interaction of codes with combinatorial designs, finite geometries, simple groups, sphere packings, kissing numbers, lattices, and association schemes. In particular, special interest is devoted to the relationship between codes and combinatorial designs. We describe and recapitulate important results in the development of the state of the art. In addition, we give illustrative examples and constructions, and highlight recent advances. Finally, we provide a collection of significant open problems and challenges concerning future research.Comment: 33 pages; handbook chapter, to appear in: "Selected Topics in Information and Coding Theory", ed. by I. Woungang et al., World Scientific, Singapore, 201

Race and Redemption: Racial and Ethnic Evolution in Rudolf Steiner\u27s Anthroposophy

With its origins in modern Theosophy, Rudolf Steiner’s Anthroposophy is built around a racial view of human nature arranged in a hierarchical framework. This article examines the details of the Anthroposophical theory of cosmic and individual redemption and draws out the characteristic assumptions about racial and ethnic difference that underlie it. Particular attention is given to textual sources unavailable in English, which reveal the specific features of Steiner’s account of “race evolution” and “soul evolution.” Placing Steiner’s worldview in its historical and ideological context, the article highlights the contours of racial thinking within a prominent alternative spiritual movement and delineates the central role of a racially configured conception of evolution within Anthroposophy past and present

The Library of Rudolf Steiner: The Books in English

The New Age philosopher, Rudolf Steiner (1861-1925), was the most prolific and arguably the most influential philosopher of his era. He assembled a substantial library, of approximately 9,000 items, which has been preserved intact since his death. Most of Rudolf Steiner’s books are in German, his native language however there are books in other languages, including English, French, Italian, Swedish, Sanskrit and Latin. There are more books in English than in any other foreign language. Steiner esteemed English as “a universal world language”. The present paper identifies 327 books in English in Rudolf Steiner’s personal library. Fifty percent of the English-language books identified are on Theosophy (n=164). Rudolf Steiner was the General Secretary of the German branch of the Theosophy Society from 1902, and he hived off his own Anthroposophy Society in 1912. The present study reveals that Steiner maintained his interest in Theosophy throughout his life as he stayed up to date with the proliferating portfolio of Theosophy publications. The publication dates of Steiner’s Theosophy collection range from 1877 to 1923. The leading exponents of Theosophy in his day are well represented in Steiner’s collection, including Annie Besant (n=61), Charles Leadbeater (n=13), William Westcott (n=13) and Helena Blavatsky (n=10). Of the other 50% of the Anglo-books identified, 20% are in the category of Religion (n=67), 10% are Social Science (n=33), 6% are Philosophy (n=21), 4% are Science (n=13), and 3% each are Anthroposophy (n=11), History (n=9) and Arts (n=9). The publication dates of Steiner’s Anglo-books span the period 1659 to 1925. This demonstrates that Steiner was acquiring Anglo-books right to the end of his life. The Steiner library throws light on the development of the thoughts of this remarkable individual and the present paper reveals Steiner’s engagement throughout his life with the world of Anglo-publishing and thought

Hilbert's Program Then and Now

Hilbert's program was an ambitious and wide-ranging project in the philosophy and foundations of mathematics. In order to "dispose of the foundational questions in mathematics once and for all, "Hilbert proposed a two-pronged approach in 1921: first, classical mathematics should be formalized in axiomatic systems; second, using only restricted, "finitary" means, one should give proofs of the consistency of these axiomatic systems. Although Godel's incompleteness theorems show that the program as originally conceived cannot be carried out, it had many partial successes, and generated important advances in logical theory and meta-theory, both at the time and since. The article discusses the historical background and development of Hilbert's program, its philosophical underpinnings and consequences, and its subsequent development and influences since the 1930s.Comment: 43 page

South-South cooperation in health professional education : a literature review

In the literature on the evolution of funding approaches there is criticism of traditional funding strategies and the promotion of inclusive models, such as South-South Cooperation (SSC) and triangular models. The latter are felt to have a number of advantages. This article has four broad objectives: (i) to present a literature review on the evolution of Southern approaches to development co-operation; (ii) to indicate examples of current co-operative programmes in health and health professional education in Africa; (iii) to assess the advantages and disadvantages of these models; and (iv) to mention some emerging issues in monitoring and evaluation. The Boolean logic approach was used to search for applicable literature within three topic layers. Searches were conducted using PubMed, PLoS and other accessible databases. An initial draft of the article was presented to a group of academics and researchers at the Flemish Inter-University Council (VLIR-UOS) Primafamed annual workshop held in August 2010 in Swaziland. Comments and suggestions from the group were included in later versions of the article. It is important to note that the existence of various funding models implemented by a variety of actors makes it difficult to measure their effects. In health and health professional education, however, SSC and triangular models of aid provide conditions for more effective programming through their focus on participation and long-term involvement. With an eye towards evaluating programmes, a number of salient issues are emerging. The importance of context is highlighted