A graph U is (induced)-universal for a class of graphs X if every member of X is contained in U as an induced subgraph. We study the problem of finding a universal graph with minimum number of vertices for various classes of bipartite graphs: exponential classes of bipartite (and general) graphs, bipartite chain graphs, bipartite permutation graphs, and general bipartite graphs. For exponential...

We propose a simple method that, given a symbol distribution, yields upper and lower bounds on the average code length of a D-ary optimal code over that distribution. Thanks to its simplicity, the method permits deriving analytical bounds for families of parametric distributions. We demonstrate this by obtaining new bounds, much better than the existing ones, for Zipf and exponential distributi...

When the distribution of lifetimes is 2-parameter exponential, Balasooriya [6] provided a failure-censored reliability sampling-plan to save test time. This paper extends the Balasooriya sampling plan to the Weibull distribution and provides a limited failure-censored reliability sampling plan (LFCR) to do life testing when test facilities are scarce. The -expected test time of the LFCR is comp...

ABSTRACT The paper considers simple queueing systems with multiple MAP servers, where the incoming customers can be freely assigned with service unit in case of more than one available free servers. In case of a well defined service policy the analysis of such queueing systems is a standard matrix analytic procedure, but the optimal control of those queues is rather complex. We do not directly ...

This paper applies the block control method to design a decomposed finite spectrum assignment control law suitable for multivariable linear time-delay systems. A block controllable form is introduced and a non-singular transformation that reduces the system to this form is proposed. Conditions of stability of the closed-loop system are derived. Copyright © 2002 IFAC

In this paper, we propose a nonlinear model for magnetic levitation systems which is validated with experimental measurements. Using this model, a nonlinear control law based on differential geometry is firstly synthesized. Then, its real-time implementation is developed. In order to highlight the performance of the proposed control law, experimental results are given.

in this paper an approach based on evolutionary algorithms to find pareto optimal pair of state and control for multi-objective optimal control problems (moocp)'s is introduced‎. ‎in this approach‎, ‎first a discretized form of the time-control space is considered and then‎, ‎a piecewise linear control and a piecewise linear trajectory are obtained from the discretized time-control space using ...

In this paper we introduce a modification of the free boundary problem related to optimal stopping problems for diffusion processes. This modification allows to apply this PDE method also in cases where the usual regularity assumptions on the coefficients and on the gain function are not satisfied. We apply this method to the optimal stopping of integral functionals with exponential discount of...

We consider the problem of maximizing terminal utility in a model where asset prices are driven by Wiener processes, but where the various rates of returns are allowed to be arbitrary semimartingales. The only information available to the investor is the one generated by the asset prices and, in particular, the return processes cannot be observed directly. This leads to an optimal control probl...

We study the area requirement of bar-visibility and rectangle-visibility representations of trees in the plane. We prove asymptotically tight lower and upper bounds on the area of such representations, and give linear-time algorithms that construct representations with asymptotically optimal area. @ 1997 Elsevier Science B.V.