Search results for "Trajectory"
showing 10 items of 203 documents
Solving chance constrained optimal control problems in aerospace via Kernel Density Estimation
2017
International audience; The goal of this paper is to show how non-parametric statistics can be used to solve some chance constrained optimization and optimal control problems. We use the Kernel Density Estimation method to approximate the probability density function of a random variable with unknown distribution , from a relatively small sample. We then show how this technique can be applied and implemented for a class of problems including the God-dard problem and the trajectory optimization of an Ariane 5-like launcher.
Event-Based Trajectory Prediction Using Spiking Neural Networks
2021
International audience; In recent years, event-based sensors have been combined with spiking neural networks (SNNs) to create a new generation of bio-inspired artificial vision systems. These systems can process spatio-temporal data in real time, and are highly energy efficient. In this study, we used a new hybrid event-based camera in conjunction with a multi-layer spiking neural network trained with a spike-timing-dependent plasticity learning rule. We showed that neurons learn from repeated and correlated spatio-temporal patterns in an unsupervised way and become selective to motion features, such as direction and speed. This motion selectivity can then be used to predict ball trajectory…
Semantic Trajectory Modeling for Dynamic Built Environments
2017
This paper presents a data model to capture moving and changing objects in the context of dynamic built environment. Building elements are subject to change which represents semantic trajectories crossing trajectories of users. These semantic trajectories in dynamics built environment permit to capture fine-grained activities and behaviors of users and objects. The data model is based on ontology and description logics to capture logic constraints on semantic trajectories.
Becoming a multilingual health professional in vocational education - two adult migrants’ translanguaging trajectories
2022
The number of migrant students in vocational education in Finland is rising. Their educational backgrounds and language resources are diverse, and research is needed to gain better understanding on how their existing knowledge can be acknowledged, supported, and deployed when they become multilingual professionals in their own fields. In this ethnographic study, we drew on the theoretical approaches of translanguaging and language architecture (García, O., and T.Kleyn. 2016. “Translanguaging Theory in Education.” In Translanguaging with Multilingual Students: Learning from Classroom Moments, edited by O. García, and T. Kleyn, 9–33. New York, London: Routledge; Li, Wei. 2018. “Translanguagin…
Career intentions of Australian physical education teachers
2015
The purpose of this study was to investigate Australian physical education (PE) teachers’ career intentions and factors influencing their intentions. A sample (N = 234) of Western Australian PE teachers responded to a questionnaire determining PE teachers’ work and the primary motivators for intention to leave the profession. Half (51.3%) of the respondents wanted a change from their current PE teacher job and 39.8% were intending to leave PE teaching. The most frequent reasons for wanting to leave PE related to: non-use of expertise, workload, school administration, and lack of opportunities for personal and professional development. Consideration should be given to mediation strategies th…
Career intentions of Australian physical education teachers
2015
The purpose of this study was to investigate Australian physical education (PE) teachers’ career intentions and factors influencing their intentions. A sample ( N = 234) of Western Australian PE teachers responded to a questionnaire determining PE teachers’ work and the primary motivators for intention to leave the profession. Half (51.3%) of the respondents wanted a change from their current PE teacher job and 39.8% were intending to leave PE teaching. The most frequent reasons for wanting to leave PE related to: non-use of expertise, workload, school administration, and lack of opportunities for personal and professional development. Consideration should be given to mediation strategies t…
Energy Efficient Optimization for Solar-Powered UAV Communications System
2021
In this work, we explore the energy efficiency optimization for a solar-powered unmanned aerial vehicle (UAV) communications system. We consider a scenario where a number of ground users (GUs) connect with a solar-powered multi-antenna UAV over a wireless link. First, we are able to derive the relations between the uplink data rate and heading angle of UAV and transmission power of GUs. In addition, the harvested energy from solar light is also affected by UAV’s angle. Accordingly, with the objective to maximize the energy efficiency that is related to uplink data rate and energy consumption, we propose to dynamically adjust the UAV trajectory and gesture, by optimizing its velocity, accele…
A measurement-based trajectory model for drifted motions towards a target zone
2016
Trajectory models have numerous applications in the area of wiewlwss communications. The aim of this paper is to develop an empirical trajectory model for drifted motions. Recently, a highly flexible trajectory model based on the primitives of Brownian fields (TramBrown) was proposed by A. Borhani and M. Patzold. This paper provides an empirical proof for TramBrown using global positioning system (GPS) data collected from real life user traces drifting to a particular target point or a zone. The recorded location coordinates of the mobile user are processed to compute the total travelling length and the angle-of-motion (AOM) along the drifted trajectory. It is shown that the probability den…
Collision Avoidance Trajectory for an Ekranoplan.
2009
The risk of collision is one of the crucial aspects for the applications of Ekranoplans in civil transportation. In fact, the extremely low flight altitude of these aircraft increases dramatically the chances of interference between their flight path and the multitude of obstacles populating the surrounding area. In this work we consider the optimal collision avoidance problem between a cruising Ekranoplan and a steady obstacle located on its flight path. First we solve the optimal control problem imposing that the collision avoidance maneuver lies on the longitudinal plane identified by the initial cruising conditions. In the second part of this work we state the three-dimensional version …
Motion-control techniques of today and tomorrow: a review and discussion of the challenges of controlled motion
2020
Motion-control technologies are at the core of multiple mechatronic products and applications. Wherever actuated motion takes place in machines and components, either position or force setting (or trajectory tracking), or even a combination of both, are demanded from the control system. In high-performance mechatronic systems, including micro- and/or nanoscale motion (such as data-storage devices, machine tools, manufacturing tools for electronics components, and industrial robots), the required specifications in motion performance, such as response/settling time and trajectory/settling accuracy, should be sufficiently achieved [1].