Optimal sensor arrangements in Angle of Arrival (AoA) and range based localization with linear sensor arrays

This paper investigates the linear separation requirements for Angle-of-Arrival (AoA) and range sensors, in order to achieve the optimal performance in estimating the position of a target from multiple and typically noisy sensor measurements. We analyse the sensor-target geometry in terms of the Cramer–Rao inequality and the corresponding Fisher information matrix, in order to characterize localization performance with respect to the linear spatial distribution of sensors. Here in this paper, we consider both fixed and adjustable linear sensor arrays

A Practical Guide to the Automated Analysis of Vascular Growth, Maturation and Injury in the Brain

The distinct organization of the brain’s vasculature ensures the adequate delivery of oxygen and nutrients during development and adulthood. Acute and chronic pathological changes of the vascular system have been implicated in many neurological disorders including stroke and dementia. Here, we describe a fast, automated method that allows the highly reproducible, quantitative assessment of distinct vascular parameters and their changes based on the open source software Fiji (ImageJ). In particular, we developed a practical guide to reliably measure aspects of growth, repair and maturation of the brain’s vasculature during development and neurovascular disease in mice and humans. The script can be used to assess the effects of different external factors including pharmacological treatments or disease states. Moreover, the procedure is expandable to blood vessels of other organs and vascular in vitro models. © Copyright © 2020 Rust, Kirabali, Grönnert, Dogancay, Limasale, Meinhardt, Werner, Laviña, Kulic, Nitsch, Tackenberg and Schwab

Turkish language reform in a language planning framework: Its impact on language use of Turkish Cypriot high school students

This study investigates twentieth century Turkish language reform in a language planning framework and looks at the ways in which the language has been renovated and purified in line with the evolving sociopolitical ideologies of the times. The current impact of Turkish language reform on mother tongue education in the Turkish Cypriot community is examined through analysis of language education policies, interviews with inspectors and teachers, and a survey of 213 high school students. Students\u27 knowledge and usage of pure Turkish words (neologisms) proposed during the renovation of the lexicon are explored. Statistical measures were used to compare the students from a Turkish-medium school with those from an English-medium school. Associations were sought between language knowledge and use, and variables such as the medium of instruction, socioeconomic status, general academic achievement, and exposure to media. Findings indicate that the initial impact of the Turkish language reform, as reflected in the reinforcement of purified/simplified Turkish words in education, has attenuated over the years. Policies on mother tongue education do not reinforce pure Turkish. Inspectors and teachers oppose exaggerated purism in language due to the confusion it creates for learners. Nevertheless, the survey reveals that students have been learning the Turkish neologisms implemented by the media. Overall, the students\u27 background, that is, the education level of their parents, home location, the amount of television they watch, and their general academic achievement have the greatest influence on their knowledge of Turkish neologisms, the latter being the most important. Students of the more competitive English-medium school have better knowledge of these neologisms, despite fewer hours of formal exposure to the language. Furthermore, knowledge, and hence acquisition, of neologisms is not dependent upon the commonness of their components, nor on their being coined grammatically. This study shows that although initially it was very successful, the Turkish language reform movement has somewhat lost its impetus. Though many words coined during the reform are now well entrenched in the language, learners have problems with certain lexical items and grammar rules, necessitating further language planning

Optimal Geometries for AOA Localization in the Bayesian Sense

This paper considers the optimal sensor placement problem for angle-of-arrival (AOA) target localization in the 2D plane with a Gaussian prior. Optimal sensor locations are analytically determined for a single AOA sensor using the D- and A-optimality criteria and an approximation of the Bayesian Fisher information matrix (BFIM). Optimal sensor placement is shown to align with the minor axis of the prior covariance error ellipse for both optimality criteria. The approximate BFIM is argued to be valid for a sufficiently small prior covariance compared with the target range. Optimal sensor placement results obtained for Bayesian target localization are extended to manoeuvring target tracking. For sensor trajectory optimization subject to turn-rate constraints, numerical search methods based on the D- and A-optimality criteria as well as a new closed-form projection algorithm that aims to achieve alignment with the minor axis of the prior error ellipse are proposed. It is observed that the two optimality criteria generate significantly different optimal sensor trajectories despite having the same optimal sensor placement for the localization of a stationary target. Analysis results and the performance of the sensor trajectory optimization methods are demonstrated with simulation examples. It is observed that the new closed-form projection algorithm achieves superior tracking performance compared with the two numerical search methods