A data structure is presented for the Mergeable Dictionary abstract data type, which supports the following operations on a collection of disjoint sets of totally ordered data: PredecessorSearch, Split and Merge. While Predecessor-Search and Split work in the normal way, the novel operation is Merge. While in a typical mergeable dictionary (e.g. 2-4 Trees), the Merge operation can only be perfo...

The honeycomb lattice of graphene is characterized by linear dispersion and pseudospin chirality of fermions on the Dirac cones. If lattice anisotropy is introduced, the Dirac cones stay intact but move in reciprocal space. Dirac point movement can lead to a topological transition from semimetal to semiconductor when two inequivalent Dirac points merge, an idea that has attracted significant re...

An established approach to training Gaussian Mixture Models (GMMs) for speaker verification is via the expectation-maximisation (EM) algorithm. The EM algorithm has been shown to be sensitive to initialisation and prone to converging on local maxima. In exploration of these issues, three different initialisation methods are implemented, along with a split and merge technique to ‘pull’ the train...