Performance Evaluation of Vision-Based Algorithms for MAVs

An important focus of current research in the field of Micro Aerial Vehicles (MAVs) is to increase the safety of their operation in general unstructured environments. Especially indoors, where GPS cannot be used for localization, reliable algorithms for localization and mapping of the environment are necessary in order to keep an MAV airborne safely. In this paper, we compare vision-based real-time capable methods for localization and mapping and point out their strengths and weaknesses. Additionally, we describe algorithms for state estimation, control and navigation, which use the localization and mapping results of our vision-based algorithms as input.Comment: Presented at OAGM Workshop, 2015 (arXiv:1505.01065

Dynamical behaviour on the parameter space: new populational growth models proportional to beta densities

We present new populational growth models, generalized logistic models which are proportional to beta densities with shape parameters p and 2, where p > 1, with Malthusian parameter r. The complex dynamical behaviour of these models is investigated in the parameter space (r, p), in terms of topological entropy, using explicit methods, when the Malthusian parameter r increases. This parameter space is split into different regions, according to the chaotic behaviour of the models

Loudness measurement of multitrack audio content using modifcations of ITU-R BS.1770

The recent loudness measurement recommendations by the ITU and the EBU have gained widespread recognition in the broadcast community. The material it deals with is usually full-range mastered audio content, and its applicability to multitrack material is not yet clear. In the present work we investigate how well the evaluated perception of single track loudness agrees with the measured value as de ned by ITU-R BS.1770. We analyze the underlying features that may be the cause for this disparity and propose some parameter alterations that might yield better results for multitrack material with minimal modi cation to their rating of broadcast content. The best parameter sets are then evaluated by a panel of experts in terms of how well they produce an equal-loudness multitrack mix, and are shown to be signi cantly more successful

Medico-legal age estimation in a sub-adult portuguese population: validation of Atlas Schour and Massler and London

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited."Introduction: Age estimation in children and adolescents often depends on morphological methods, such as examination of dental development. Objectives: The aim of this project was to validate, in a Portuguese population, two forensic methods of dental age estimation – Schour and Massler charts and the London atlas. Materials and Methods: The test sample was composed by 108 dental radiographs of living and known-age individuals. Dental age was estimated according to each method. Chronological age was then compared to the estimated dental age using individual t-test and paired t-test. Results: Results showed that the Schour and Massler charts underestimated age and the London atlas overestimated age. Nevertheless, the London atlas performed better in all measures. Mean differences for both the London atlas and Schour and Massler were 0,1389 and -5,4167 months respectively. Schour and Massler charts showed significant statistical difference between dental age and chronological age (p <0.05). Discussion and Conclusions: We conclude that, in the evaluated sample, age estimation using the London atlas represents an improvement in forensic age estimation from developing teeth. Further studies should be done with a larger Portuguese population sample.

The medico-legal importance of establishing human identity by palatal rugoscopy: evaluation of the immutability and individuality of palatal rugae under the influence of ante mortem orthodontic treatment

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited."Introduction: The palatal rugae can be an alternative method of forensic identification. Through the years, several investigations focused on the effect of orthodontic treatment in the palatal rugae pattern. Objectives: Evaluate the concepts of immutability and individuality of the palatal rugae in a Portuguese adult population submitted to orthodontic treatment, for the purpose of medico-legal identification through Thomas and Kotze classification system. Additionally, we wanted to establish comparison of the palatal rugae of each subject, and between genders. Materials and Methods: Thirty three pairs of study dental casts, from thirty three patients submitted to orthodontic treatment in the Department of Orthodontics in College of Dentistry - University of Lisbon, were photographed and classified according to the classification system described by Thomas and Kotze. We proceeded to a statistical analysis running SPSS for Windows, version 20.0, using descriptive analysis and tests, with an inclusion level p <0.05. The tests applied were normality tests and T Student for paired samples. Results: The number and length of primary rugae remain identical when comparing the situation before and after orthodontic treatment. The number of secondary rugae decreases after orthodontic treatment. The variation of the angle of divergence was not statistically significant. The area of primary rugae presented statistically significant reduction after orthodontic treatment. There has no statistically significant differences between genders for total number number of rugae or average length of primary rugae (p <0.05). Discussion and Conclusion: The palatal rugae pattern does not remain stable after orthodontic treatment, and this refutes the supposed long term stability of the palatal rugae pattern. Therefore, it influences the ability to establish a positive medico-legal identification of a recent copse, if the person was submitted to ante mortem orthodontic treatment. The identification might still be possible if we possess a last ante mortem palatal record in these situations, to allow identification based on positive individual characteristics, through comparison with the post-mortem record. Considering gender, no statistically significant differences were found. This subject remains controversial and deserves further research.

A hierarchical cluster system based on Horton-Strahler rules for river networks

We consider a cluster system in which each cluster is characterized by two parameters: an \order" i; following Horton-Strahler's rules, and a \mass" j following the usual additive rule. Denoting by ci;j (t) the concen- tration of clusters of order i and mass j at time t; we derive a coagulation- like ordinary di erential system for the time dynamics of these clusters. Results about existence and the behaviour of solutions as t ! 1 are ob- tained, in particular we prove that ci;j (t) ! 0 and Ni(c(t)) ! 0 as t ! 1; where the functional Ni( ) measures the total amount of clusters of a given xed order i: Exact and approximate equations for the time evolution of these functionals are derived. We also present numerical results that sug- gest the existence of self-similar solutions to these approximate equations and discuss its possible relevance for an interpretation of Horton's law of river number