Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are bipartite. As main results, we show that in this context the Moore-like bound is attained in the case of diameter k = 3, and that bipartite mixed graphs of diameter k ≥ 4 do not exist.

OBJECTIVES The aim of the study was to address the need for quantifying the global cancer time evolution magnitude from a pair of time-consecutive positron emission tomography-computed tomography (PET-CT) scans. In particular, we focus on the computation of indicators using image-processing techniques that seek to model non-Hodgkin's lymphoma (NHL) progression or response severity. MATERIALS ...

Real-world phenomena are frequently modelled by Bayesian hierarchical models. The building-blocks in such models are the distribution of each variable conditional on parent and/or neighbour variables in the graph. The specifications of centre and spread of these conditional distributions may be well motivated, whereas the tail specifications are often left to convenience. However, the posterior...

Recently, it has been demonstrated that graphical models promise some potential for expressing causal concepts, see for example Pearl (2000), Lauritzen (2001), or Dawid (2002). The causal interpretation is most direct in models based on directed acyclic graphs, whereas causal interpretation for chain graph models generally is more subtle and complex (Lauritzen and Richardson 2002). In the artic...

This paper introduces a class of graphical independence models that is closed under marginalization and conditioning but that contains all DAG independence models. This class of graphs, called maximal ancestral graphs, has two attractive features: there is at most one edge between each pair of vertices; every missing edge corresponds to an independence relation. These features lead to a simple ...

OBJECTIVES Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely availab...

Visualization and virtual environments (VEs) have been two interconnected parallel strands in visual computing for decades. Some VEs have been purposely developed for visualization applications, while many visualization applications are exemplary showcases in general-purpose VEs. Because of the development and operation costs of VEs, the majority of visualization applications in practice are ye...

Although impaired visual search is a core deficit of patients with spatial neglect, current evidence is not conclusive about the mechanisms underlying this failure. We present evidence from 14 neglect patients searching for a target defined by two perceptual features that visual search is mediated by mechanisms of attentional competition. Participants were tested in three search conditions with...

A technique for the early fusion of visual lip movements and a vector of mixed speech signals is proposed. This technique involves the initial recreation of speech signals entirely from the visual lip motions of each speaker. By using geometric parameters of the lips obtained from the Tulips1 database and the Audio-Visual Speech Processing dataset, a virtual speech signal is recreated by using ...