66 research outputs found
leanEA. A poor man\u27s evolving algebra compiler
The Prolog program
term_expansion((define C as A with B), (C=>A:-B,!)).
term_expansion((transition E if C then D),
((transition E):-C,!,B,A,(transition _))) :-
serialize(D,B,A).
serialize((E,F),(C,D),(A,B)) :- serialize(E,C,B), serialize(F,D,A).
serialize(F:=G, ([G]=>*[E],F=..[
Implementing semantic tableaux
This report describes implementions of the tableau calculus for
first-order logic. First an extremely simple implementation,
called leanTAP, is presented, which nonetheless covers the full
functionality of the calculus and is also competitive with respect
to performance. A second approach uses compilation techniques for
proof search. Improvements inculding universal variables and
lemmata are considered as well as more efficient data structures
using reduced ordered binary decision diagrams. The implementation
language is PROLOG. In all cases fully operational PROLOG code is
given. For leanTAP a formal proof of the correctness of the
implementation is given relying on the operational semantics of
PROLOG as given by the SLD-tree model.
This report will appear as a chapter in the
Handbook of Tableau-based Methods in Automated Deduction
edited by: D. Gabbay, M. D\u27Agostino, R. H\"{a}hnle, and
J.Posegga
published by: KLUWER ACADEMIC PUBLISHERS
Electronic availability will be discontinued after final acceptance
for publication is obtained
On Structural Signatures for Tree Data Structures
Abstract. In this paper, we present new attacks on the redactable signature scheme introduced by Kundu and Bertino at VLDB '08. This extends the work done by Brzuska et al. at ACNS '10 and Samelin et al. at ISPEC '12. The attacks address unforgeability, transparency and privacy. Based on the ideas of Kundu and Bertino, we introduce a new provably secure construction. The corresponding security model is more flexible than the one introduced by Brzuska et al. Moreover, we have implemented schemes introduced by Brzuska et al. and Kundu and Bertino. The evaluation shows that schemes with a quadratic complexity become unuseable very fast
leanEA: A Poor Man's Evolving Algebra Compiler
The Prolog program "termexpansion((define C as A with B), (C=?A:-B,!)). termexpansion((transition E if C then D), ((transition E):-C,!,B,A,(transition ))) :- serialize(D,B,A). serialize((E,F),(C,D),(A,B)) :- serialize(E,C,B), serialize(F,D,A). serialize(F:=G, ([G]=?*[E],F=..[C---D],D=?*B,A=..[C---B]), asserta(A=?E)). [G---H]=?*[E---F] :- (G="E; G=..[C---D],D=?*B,A=..[C---B],A=?E), !,H=?*F. []=?*[]. A=?B :- [A,B]=?*[D,C], D==C." implements a virtual machine for evolving algebras. It offers an efficient and very flexible framework for their simulation
Smartcard Firewalls Revisited
Smartcards are being used as secure endpoints in computer transactions. Recently, the connectivity of smartcards has increased and future smartcards will be able to communicate over the TCP/IP protocol
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