The imperfection ratio is a graph invariant which indicates how good a lower bound the weighted clique number gives on the weighted chromatic number, in the limit as weights get large. Its introduction was motivated by investigations of the radio channel assignment problem, where one has to assign channels to transmitters and the demands for channels at some transmitters are large. In this pape...

Beyond perfection, the field to be explored is too wide. In this context, several ways to classify imperfect graphs or, equivalently, 0, 1 (clique-node) imperfect matrices can be found in the literature. From the polyhedral point of view, ideal matrices are to set covering problems what perfect matrices are to set packing problems. In fact, if a matrix is ideal, its linear relaxation is an inte...

the existence of some geometrically imperfect members, like initial curvature in a double layer space structures with hundreds or thousands of members is almost inevitable. these imperfections give rise to loss of load bearing capacity of double layer space structures. to evaluate the effect of initial member imperfection on load bearing capacity of double layer space structures and their failu...

This letter proposes a multiple parametric dictionary learning algorithm for direction of arrival (DOA) estimation in presence of array gain-phase error and mutual coupling. It jointly solves both the DOA estimation and array imperfection problems to yield a robust DOA estimation in presence of array imperfection errors and off-grid. In the proposed method, a multiple parametric dictionary lear...