This paper shows that the least absolute shrinkage and selection operator (LASSO) can provide an exact optimal solution to a special type of constrained cardinality minimization problem, which is motivated from a sensor network measurement robustness analysis problem. The constraint matrix of the considered problem is totally unimodular. This is shown to imply that LASSO leads to a tight linear...

Near a quantum-critical point in a metal strong fermion-fermion interaction mediated by a soft collective boson gives rise to incoherent, non-Fermi liquid behavior. It also often gives rise to superconductivity which masks the non-Fermi liquid behavior. We analyze the interplay between the tendency to pairing and fermionic incoherence for a set of quantum-critical models with effective dynamica...

Performance guarantees for recovery algorithms employed in sparse representations, and compressed sensing highlights the importance of incoherence. Optimal bounds of incoherence are attained by equiangular unit norm tight frames (ETFs). Although ETFs are important in many applications, they do not exist for all dimensions, while their construction has been proven extremely difficult. In this pa...

In this article, we propose a structure of threaded learning conversations taking place in virtual learning communities. This new structure aims at facilitating the emergence of learning conversations in these learning communities. These threaded conversations take place in a forum-type tool that uses a tree data structure composed of threads to organize group communication. We identify two sit...

The International System of Units (SI) is supposed to be coherent. That is, when a combination of units is replaced by an equivalent unit, there is no additional numerical factor. Here we consider dimensionless units as defined in the SI, e.g. angular units like radians or steradians and counting units like radioactive decays or molecules. We show that an incoherence may arise when different un...

this paper describes and discusses the psychopathology and demographic data of 922 schizophernic inpatients (aged 15-66) who had been diagnosed according to dsm-iii criteria in state mental hospitals of iran. data were collected via semistructured interviews (during 1985-91) by psychologists and trained research assistants from the tehran psychiatric institute. in this research depressed mood, ...