Cluster computing is becoming increasingly popular for providing cost-effective and affordable parallel computing for day-to-day computational needs [2, 11, 16]. Such environments consist of clusters of workstations connected by Local Area Networks (LANs). The possibility of the incremental expansion of clusters by incorporating new generations of computing nodes and networking technologies is ...

A two-dimensional Schrödinger operator with a constant magnetic field perturbed by a smooth compactly supported potential is considered. The spectrum of this operator consists of eigenvalues which accumulate to the Landau levels. We call the set of eigenvalues near the n’th Landau level an n’th eigenvalue cluster, and study the distribution of eigenvalues in the n’th cluster as n → ∞. A complet...

Document retrieval is a critical component of question answering (QA), yet little work has been done towards statistical modeling of queries and towards automatic generation of high quality query content for QA. This paper introduces a new, cluster-based query expansion method that learns queries known to be successful when applied to similar questions. We show that cluster-based expansion impr...

Iron oxide (FemOn) neutral clusters are generated in the gas phase through laser ablation of the metal and reaction with various concentrations of O2 in He. The mixture of expansion gas and neutral FemOn cluster species is expanded through a supersonic nozzle into a vacuum system, in which the clusters are ionized by an ArF excimer laser at 193 nm, and the ions are detected and identified in a ...

The carrier-density dependence of the photoemission spectrum of the Holstein many-polaron model is studied using cluster perturbation theory combined with an improved cluster diagonalization by Chebychev expansion.

In this paper, we report the calculated phase diagrams of V-Nb, V-Ta, and Nb-Ta alloys computed by combining the total energies of 40–50 configurations for each system (obtained using density functional theory) with the cluster expansion and Monte Carlo techniques. For V-Nb alloys, the phase diagram computed with conventional cluster expansion shows a miscibility gap with consolute temperature ...

With nary mention of a tree graph, we obtain a cluster expansion bound that includes and vastly generalizes bounds as obtained by extant tree graph inequalities. This includes applications to both two-body and many-body potential situations of the recently obtained 'new improved tree graph inequalities" that have led to the 'extra I/N! factors'. We work in a formalism coupling a discrete set of...

First-principles based cluster expansion models are the dominant approach in ab initio thermodynamics of crystalline mixtures enabling the prediction of phase diagrams and novel ground states. However, despite recent advances, the construction of accurate models still requires a careful and time-consuming manual parameter tuning process for ground-state preservation, since this property is not ...