Nonlinear supratransmission in multicomponent systems

A method is proposed to solve the challenging problem of determining the supratransmission threshold (onset of instability of harmonic boundary driving inside a band gap) in multicomponent nonintegrable nonlinear systems. It is successfully applied to the degenerate three-wave resonant interaction in a birefringent quadratic medium where the process generates spatial gap solitons. No analytic expression is known for this model showing the broad applicability of the method to nonlinear systems.Comment: 4 pages, 3 figure

Four-dimensional ultrafast electron microscopy of phase transitions

Reported here is direct imaging (and diffraction) by using 4D ultrafast electron microscopy (UEM) with combined spatial and temporal resolutions. In the first phase of UEM, it was possible to obtain snapshot images by using timed, single-electron packets; each packet is free of space–charge effects. Here, we demonstrate the ability to obtain sequences of snapshots ("movies") with atomic-scale spatial resolution and ultrashort temporal resolution. Specifically, it is shown that ultrafast metal–insulator phase transitions can be studied with these achieved spatial and temporal resolutions. The diffraction (atomic scale) and images (nanometer scale) we obtained manifest the structural phase transition with its characteristic hysteresis, and the time scale involved (100 fs) is now studied by directly monitoring coordinates of the atoms themselves

BIM in teaching — lessons learned from exploratory study

Building Information Technology bears promise to bring integration into fragmented AEC industry, as well as large potentials for optimization and management of building performance along life cycle. However, the adoption in Central Europe is much slower than in the USA or Scandinavia; the designers and planners are sceptical about BIM benefits. In order to build up capabilities and thus support BIM adoption in the practice, BIM skills have be built up already in university teaching. This endeavour is the central aim of the BIM_sustain project accomplished at the Vienna University of Technology. In winter term 2012/13 and winter term 2013/14 we accomplished interdisciplinary BIM-supported design labs with student participants from architecture, civil engineering and building science. The teams used different modelling and simulation software constellations for building design and analysis. The software-constellations were evaluated in terms of BIMinteroperability, and the design process was documented by means of time and activity assessment, surveys on team performance, process satisfaction and technology acceptance and focus group interviews. In this paper we will present the results of the evaluation of both courses and analyse the differences resulting from the different course design in the two consequent terms. The first course was dominated by the issue of interfaces, whereas the second course, where better functioning software combinations in terms of data transfer were used, was dominated by the issues related to the collaboration and teamwork. Our results are not only informative for the configuration of interdisciplinary BIM-supported university teaching, but can be derived for the practice as well, especially in the areas of project management, software usage, modelling conventions or incentive systems

Autonomous gathering of livestock using a multi-functional sensor network platform

In this paper we develop algorithms and hardware for the autonomous gathering of cattle. We present a comparison of three different autonomous gathering algorithms that employ sound and/or electric stimuli to guide the cattle. We evaluate these algorithms in simulation by extending previous behavioral simulations for cattle. We implemented one of these algorithms and present data from experiments in which cattle were equipped with sensor nodes that allowed cueing with sound and electric stimuli. We discuss the minimum requirements for algorithms and hardware for autonomous gathering

The anatomy of a horizontally impacted maxillary wisdom tooth

A completely horizontally impacted upper third molar was revealed after routine dissection of a 62-year-old human cadaver of a Caucasian male. The molar was penetrating into the maxillary sinus and there was antral dehiscence of its bony alveolus. The bony alveolus was immediately in front of the greater palatine canal contents, and the bottom of the alveolus was dehiscent towards the greater palatine foramen. Within the greater palatine canal and foramen the greater palatine artery was duplicated and the nerve was found. Such antral relations of an impacted upper third molar predispose to oroantral communications if extraction is performed, while the close neurovascular relations represent a risk factor for postextractional haemorrhage and neurosensory disturbances and must be borne in mind when deciding on or performing the extraction. (Folia Morphol 2008: 67: 154–156

Multilinear Wavelets: A Statistical Shape Space for Human Faces

We present a statistical model for $3$D human faces in varying expression, which decomposes the surface of the face using a wavelet transform, and learns many localized, decorrelated multilinear models on the resulting coefficients. Using this model we are able to reconstruct faces from noisy and occluded $3$D face scans, and facial motion sequences. Accurate reconstruction of face shape is important for applications such as tele-presence and gaming. The localized and multi-scale nature of our model allows for recovery of fine-scale detail while retaining robustness to severe noise and occlusion, and is computationally efficient and scalable. We validate these properties experimentally on challenging data in the form of static scans and motion sequences. We show that in comparison to a global multilinear model, our model better preserves fine detail and is computationally faster, while in comparison to a localized PCA model, our model better handles variation in expression, is faster, and allows us to fix identity parameters for a given subject.Comment: 10 pages, 7 figures; accepted to ECCV 201