Displaying 921 – 940 of 1497

Showing per page

On pointwise adaptive curve estimation based on inhomogeneous data

Stéphane Gaïffas (2007)

ESAIM: Probability and Statistics

We want to recover a signal based on noisy inhomogeneous data (the amount of data can vary strongly on the estimation domain). We model the data using nonparametric regression with random design, and we focus on the estimation of the regression at a fixed point x0 with little, or much data. We propose a method which adapts both to the local amount of data (the design density is unknown) and to the local smoothness of the regression function. The procedure consists of a local polynomial...

On Proactive Verifiable Secret Sharing Schemes

Nikov, Ventzislav, Nikova, Svetla, Preneel, Bart (2007)

Serdica Journal of Computing

The paper has been presented at the International Conference Pioneers of Bulgarian Mathematics, Dedicated to Nikola Obreshkoff and Lubomir Tschakaloff , Sofia, July, 2006. The material in this paper was presented in part at the 11th Workshop on Selected Areas in Cryptography (SAC) 2004This paper investigates the security of Proactive Secret Sharing Schemes. We first consider the approach of using commitment to 0 in the renewal phase in order to refresh the player's shares and we present two types of...

On quadratic Hurwitz forms. I

Jiří Gregor (1981)

Aplikace matematiky

Homogeneous quadratic polynomials f in n complex variables are investigated and various necessary and sufficient conditions are given for f to be nonzero in the set Γ ( n ) = z C ( n ) : R e z > 0 . Conclusions for the theory of multivariable positive real functions are formulated with applications in multivariable electrical network theory.

On robust consensus of multi-agent systems with communication delays

Jiangping Hu (2009)

Kybernetika

In this paper, two robust consensus problems are considered for a multi-agent system with various disturbances. To achieve the robust consensus, two distributed control schemes for each agent, described by a second-order differential equation, are proposed. With the help of graph theory, the robust consensus stability of the multi-agent system with communication delays is obtained for both fixed and switching interconnection topologies. The results show the leaderless consensus can be achieved with...

On sets of vectors of a finite vector space in which every subset of basis size is a basis

Simeon Ball (2012)

Journal of the European Mathematical Society

It is shown that the maximum size of a set S of vectors of a k -dimensional vector space over 𝔽 q , with the property that every subset of size k is a basis, is at most q + 1 , if k p , and at most q + k p , if q k p + 1 4 , where q = p k and p is prime. Moreover, for k p , the sets S of maximum size are classified, generalising Beniamino Segre’s “arc is a conic” theorem. These results have various implications. One such implication is that a k × ( p + 2 ) matrix, with k p and entries from 𝔽 p , has k columns which are linearly dependent. Another is...

On solution sets of information inequalities

Nihat Ay, Walter Wenzel (2012)

Kybernetika

We investigate solution sets of a special kind of linear inequality systems. In particular, we derive characterizations of these sets in terms of minimal solution sets. The studied inequalities emerge as information inequalities in the context of Bayesian networks. This allows to deduce structural properties of Bayesian networks, which is important within causal inference.

Currently displaying 921 – 940 of 1497