Automatic extraction of mandibular nerve and bone from cone-beam CT data

The exact localization of the mandibular nerve with respect to the bone is important for applications in dental implantology and maxillofacial surgery. Cone beam computed tomography (CBCT), often also called digital volume tomography (DVT), is increasingly utilized in maxillofacial or dental imaging. Compared to conventional CT, however, soft tissue discrimination is worse due to a reduced dose. Thus, small structures like the alveolar nerves are even harder recognizable within the image data. We show that it is nonetheless possible to accurately reconstruct the 3D bone surface and the course of the nerve in a fully automatic fashion, with a method that is based on a combined statistical shape model of the nerve and the bone and a Dijkstra-based optimization procedure. Our method has been validated on 106 clinical datasets: the average reconstruction error for the bone is 0.5 +/- 0.1 mm, and the nerve can be detected with an average error of 1.0 +/- 0.6 mm

On local influence analysis of full information item factor models

dichotomous variables, Monte Carlo EM algorithm, Q-displacement function, Gibbs sampler, conformal normal curvature,

Tourism, information technologies and sustainability: an exploratory review

Considerable attention has been paid in recent years to the fundamental changes in the global tourism system related to the emergence of information technologies (IT), and, specifically, the rise of social media. Opportunities to search travel-related information, to reserve and book, evaluate and judge; to receive travel advice and to communicate one's mobility patterns have all profoundly changed the practices of performing tourism, with concomitant repercussions for the management and marketing of businesses and destinations. This paper provides a discussion of the implications of these changes for the sustainability of the global tourism system. Based on an exploratory research design, key changes in the tourism system are identified and discussed with regard to their environmental, socio-cultural and psychological, as well as economic significance. The paper concludes that IT affects the tourism system in numerous and complex ways, with mixed outcomes for sustainability: while most changes would currently appear to be ambivalent – and some outright negative – there is considerable potential for IT to support more sustainable tourism. Yet, this would require considerable changes in the tourism system on global, national and individual business' levels, and require tourism academics to probe many new issue