Pebble minimization: the last theorems

Convergence Theorems for Generalized Alternating Minimization Procedures

The EM algorithm is widely used to develop iterative parameter estimation procedures for statistical models. In cases where these procedures strictly follow the EM formulation, the convergence properties of the estimation procedures are well understood. In some instances there are practical reasons to develop procedures that do not strictly fall within the EM framework. We study EM variants in ...

Folk Theorems on the Determinization and Minimization of Timed Automata

Timed automata are known not to be complementable or determinizable. Natural questions are, then, could we check whether a given TA enjoys these properties? These problems are not algorithmically solvable. Minimizing the “resources” of a TA (number of clocks or size of constants) are also unsolvable problems. In this paper we provide simple undecidability proofs using a “constructive” version o...

Extensions of Minimization Theorems and Fixed Point Theorems on a Quasimetric Space

We introduce the new concepts of e-distance, e-type mapping with respect to some e-distance and S-complete quasimetric space, and prove minimization theorems, fixed point theorems, and variational principles on an S-complete quasimetric space. We also give some examples of quasimetrics, e-distances, and e-type mapping with respect to some e-distance. Our results extend, improve, and unify many ...

Study on Pebble-Fluid Interaction Effect in Pebble Bed Reactors

INTRODUCTION In pebble bed reactors (PBRs), fuel pebbles containing TRISO particles continuously circulate within the core during operation, while the coolant fluid, either helium gas (in Pebble Bed Gas-cooled Reactors) or molten flibe salt (in Pebble Bed-Advanced High Temperature Reactors), continuously passes through the pebbles to transfer the heat generated by fission reactions out of the c...

Pebble Macro Tree Transducers with Strong Pebble Handling