On common index divisors and non-monogenity of number fields defined by x5+ax3+bx^5+ax^3+b

Let $K$ be a number field generated by a complex root $\theta$ of a monic irreducible trinomial $F(x)= x^5+ax^3+b \in \mathbb{Z}[x]$ where $ab \neq 0$. In this paper, we provide some explicit conditions only on $a$ and $b$ for which $2$ divides the index of $K$. We give necessary and sufficient condition for which $3$ divides the index of $K$. As an application of our results, we provide some infinite parametric families of number fields which are non-monogenic.Comment: submitted. arXiv admin note: substantial text overlap with arXiv:2203.10413, arXiv:2203.07625, arXiv:2206.1434

Computing an Optimal Control Policy for an Energy Storage

We introduce StoDynProg, a small library created to solve Optimal Control problems arising in the management of Renewable Power Sources, in particular when coupled with an Energy Storage System. The library implements generic Stochastic Dynamic Programming (SDP) numerical methods which can solve a large class of Dynamic Optimization problems. We demonstrate the library capabilities with a prototype problem: smoothing the power of an Ocean Wave Energy Converter. First we use time series analysis to derive a stochastic Markovian model of this system since it is required by Dynamic Programming. Then, we briefly describe the "policy iteration" algorithm we have implemented and the numerical tools being used. We show how the API design of the library is generic enough to address Dynamic Optimization problems outside the field of Energy Management. Finally, we solve the power smoothing problem and compare the optimal control with a simpler heuristic control.Comment: Part of the Proceedings of the 6th European Conference on Python in Science (EuroSciPy 2013), Pierre de Buyl and Nelle Varoquaux editors, (2014

Mobile Robot Localization Using Bar Codes as Artificial Landmarks

"Where am I' is the central question in mobile robot navigation. Robust and reliable localization are of vital importance for an autonomous mobile robot because the ability to constantly monitor its position in an unpredictable, unstructured, and dynamic environment is the essential prerequisite to build up and/or maintain environmental maps consistently and to perform path planning. Thus, selflocalization as precondition for goal-oriented behavior is a fundamental property an autonomous mobile robot needs to be equipped with. Accurate, flexible and low-cost localization are important issues for achieving autonomous and cooperative motions of mobile robots. Mobile robots usually perform self-localization by combining position estimates obtained from odometry or inertial navigation with external sensor data. The objective of the thesis is to present a pragmatic idea which utilizes a camera-based bar code recognition technique in order to support mobile robot localization In indoor environments. The idea is to further improve already existing localization capabilities, obtained from dead-reckoning, by furnishing relevant environmental spots such as doors, stairs, etc. with semantic information. In order to facilitate the detection of these landmarks the employment of bar codes is proposed. The important contribution of the thesis is the designing of two software programs. The first program is the bar code generation program which is able to generate five types of bar code labels that play a major role in the proposed localization method. The second program is the bar code recognition program that analyzes image files looking for a bar code label. If a label is found the program recognizes it and display both the information it contains and its coding type. Results concerning the generation of five types of bar code labels which are code 2 of 5, code 3 of9 , codabar code, code 128 and code 2 of 5 interleaved and the detection and identification of these labels from image files are obtained. In conclusion the thesis proposes a solution to mobile robot self-localization problem, which is the central significant for implementing an autonomous mobile robot, by utilizing a camera-based bar code recognition technique to support the basic localization capabilities obtained from a dead-reckoning method in an indoor environment

Out-of-home activity analysis using a low-resolution visual sensor

Loneliness and social isolation are probably the most prevalent psychosocial problems related to aging. One critical component in assessing social isolation in an unobtrusive manner is to measure the out-of-home activity levels, as social isolation often goes along with decreased physical activity, decreased motoric functioning, and a decline in activities of daily living, all of which may lead to a reduction in the amount of time spent out-of-home. In this work, we propose to use a single visual sensor for detecting out-of-home activity. The visual sensor has a very low spatial resolution (900 pixels), which is a key feature to ensure a cheap technology and to maintain the user’s privacy. Firstly, the visual sensor is installed in a top view setup at the door entrance. Secondly, a correlation-based foreground detection method is used to extract the foreground. Thirdly, an Extra Trees Classifier (ETC) is trained to classify the directionality of the person (in/out) based on the motion of the foreground pixels. Due to the nature of variability of the out-of-home activity, the relative frequency of the directionality (in/out) is measured over a window of 3 seconds to determine the final result. We installed our system in 9 different service flats in the UK, Belgium and France where the same ETC model is used. We evaluate our method on video sequences captured in real-life environments from the different setups, where the persons’ out-of-home routines are recorded. The results show that our approach of detecting out-of-home activity achieves an accuracy of 91.30%

Dynamic output-feedback passivity control for fuzzy systems under variable sampling

This paper concerns the problem of dynamic output-feedback control for a class of nonlinear systems with nonuniform uncertain sampling via Takagi-Sugeno (T-S) fuzzy control approach. The sampling is not required to be periodic, and the state variables are not required to be measurable. A new type fuzzy dynamic output-feedback sampled-data controller is constructed, and a novel time-dependent Lyapunov-Krasovskii functional is chosen for fuzzy systems under variable sampling. By using Lyapunov stability theory, a sufficient condition for very-strict passive analysis of fuzzy systems with nonuniformuncertain sampling is derived. Based on this condition, a novel fuzzy dynamic output-feedback controller is designed such that the closed-loop system is very-strictly passive. The existence condition of the controller can be solved by convex optimization approach. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method

Conception et Mise en Oeuvre d’un Emulateur de Chaînes de Conversion avec Lissage : Applications aux Houlogénérateurs Directs

National audienceL'intégration au réseau de la production des sources d'énergies marines renouvelables est une problématique majeure : lissage de la production, respect de la contrainte de qualité d'énergie, autant de travaux à mener afin d'accroître le taux de pénétration de ces sources dans les réseaux électriques futurs. Ainsi le développement des bancs de test s'avère indispensable pour étudier et contribuer à la validation de tels travaux. Cet article présente la modélisation et la conception d'un dispositif permettant de valider des modèles énergétiques de la chaine électrique d'un houlogénérateur et tester matériellement les lois de gestion du lissage. Le système est composé de deux ponts triphasés dos-à-dos : un pont émulant l'ensemble convertisseur-génératrice avec sa loi de récupération d'énergie et un autre pont injectant l'énergie au réseau, et d'un système de lissage composé essentiellement d'un hacheur réversible et d'un banc de supercondensateurs, piloté selon une loi de gestion donnée

Design of an electro-mechanical portable system using natural human body movements for electricity generation

International audienceIn this article, the authors present the energy potential associated with an electromechanical resonant generator that uses natural movements of the human body during walking motion, as a means of increasing the autonomy of portable electronic systems. The article begins by characterizing the human walk in terms of frequency and hip displacement amplitude. A combined mechanical and electrical study is then conducted in order to determine an order of magnitude for recoverable power

Electromagnetic Resonant Generator

International audienceIn this paper, the authors present the energy production potential of a mechanically-resonant electrical generator system, which makes use of natural human walking movements. The characteristics associated with the human walk will be discussed first, followed by the electromechanical modeling approach employed. The choice of electromechanical architecture will be justified and the permanent magnet and moving coil structure can then be modeled and optimized. A demonstration device has also been generated and tested in order to validate the concept developed as well as the theoretical models derived

Optimization Material Distribution methodology: Some electromagnetic examples

International audienceIn this paper, a new approach towards Optimization Material Distribution (OMD) is proposed. The principle behind this approach is to use a surface genetic algorithm to determine material distribution within a fixed Finite Element Computation mesh. The method proves to be highly adaptive to various kinds of electromagnetic actuator optimization approaches. Several optimal electromagnetic examples are presented