В диссертации были исследованы вероятные риски и новые возможности цифрового государственного управления. Изучены сущность, типы и особенности цифровых платформ. Исследованы современные тенденции цифровой трансформации государственного управления. Осуществлена оценка процессов в области информатизации органов государственного управления ДНР. Разработана полная модель архитектуры Единого портала государственных услуг. Разработан проект внедрения Единого портала государственных услуг. Разработана и реализована системно-динамическая модель оценки уровня информатизации органов государственного управления. Осуществлена оценка эффективности внедрения Единого портала государственных услуг. / The dissertation explored the likely risks and new opportunities for digital government. The essence, types and features of digital platforms are studied. The current trends in the digital transformation of public administration have been studied. An assessment of the processes in the field of informatization of the state administration bodies of the DPR was carried out. A complete model of the architecture of the Unified Portal of Public Services has been developed. A project for the implementation of the Unified Portal of Public Services has been developed. A system-dynamic model for assessing the level of informatization of government bodies has been developed and implemented. An assessment was made of the effectiveness of the implementation of the Unified Portal of Public Services.

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<p dir="ltr">Distributed energy resources (DERs), such as rooftop solar generation and energy storage systems, are becoming more prevalent in distribution systems. DERs are connected to the distribution system via power electronic converters, introducing faster dynamics in the system. Understanding the system dynamics under a high penetration of inverter-based DERs is critical for power system researchers and practitioners, driving the development of modeling techniques and simulation software. Aiming to reduce computational complexity, existing tools and techniques often employ various approximations. Meanwhile, modern advancements in computational hardware capabilities provide opportunities to include the faster time-scale dynamics. To address this, the primary objective of this thesis is to develop an open-source Python simulation package, Dynamic Simulation using Sparse Tableau Approach in Python, DynaSTPy (pronounced “dynasty”), capable of capturing the dynamics of all components in a distribution feeder. The distribution feeder is modeled as a system of Differential-Algebraic Equations (DAEs). Further, each component in the feeder is modeled based on the Sparse Tableau Approach (STA), which involves the representation of component model equations using sparse matrices, facilitating a systematic procedure to model the components and construct the system DAEs. In sinusoidal steady state, the DAEs can be represented in phasor form, extending the approach to perform power flow analysis of distribution feeders.</p>

La consommation énergétique dans l’industrie augmente de nos jours, avec l’amplification des activités industrielles dans le monde. En parallèle, la pénurie des énergies primaires et le réchauffement climatique obligent des exploitations sans cesse des énergies et des techniques alternatives, afin de développer durablement, et de satisfaire l’augmentation de la consommation. Ainsi, l’amélioration de l’utilisation énergétique dans l’industrie devient aussi un sujet important à développer et à étudier. Dans certains sites industriels, les rejets thermiques sont énormément dégagés dans l’environnement sans aucun traitement énergétique. Ses températures sont parfois, beaucoup plus élevées que l’ambiant. La valorisation de ces chaleurs est conseillée, par des systèmes de valorisation, pour la production de chaud, de froid et d’électricité. Ce traitement peut réduire significativement le gaspillage et améliorer l’efficacité énergétique dans l’industrie. C’est pour cette raison, plusieurs projets sont lancés. Le projet VALENTHIN (VALorisation ENergétique des rejets THermiques INdustriels) est pour but d’améliorer l’efficacité énergétique industrielle en valorisant les rejets thermiques ou en développant les processus industriels. Cette thèse concentre sur les études des systèmes de valorisation, particulièrement en ce qui concerne les différentes méthodes de simulation. Dans cette thèse, les bibliographies sont synthétisées, sur les différentes modélisations des systèmes de valorisation, surtout le système à absorption et le cycle de Rankine organique mentionnés dans ce projet. Par conséquent, une stratégie de modélisation est proposée et est montrée, pour les simulations des systèmes en régime permanent et en régime dynamique. Le choix des types de modélisation doit prendre en compte leurs avantages et leurs inconvénients, et aussi les besoins des utilisateurs, pour but de modéliser et développer des systèmes plus aisément et plus efficacement. / Energy consumption in industry is increasing today, with the amplification of industrial activities in the world. At the same time, the scarcity of primary energy and global warming are insist the use of alternative technologies and energies, in order to sustainably develop, and to satisfy the increase in consumption. Thus, improving energy use in industry is also becoming an important topic to be developed and studied. In some industrial sites, the waste heats are enormously released into the environment without any energy treatment. Its temperatures are sometimes, much higher than the ambient. The valorization of these heats is advised, by using the valorization systems, for the production of hot, cold and electricity. This treatment can significantly reduce the energy waste and improve energy efficiency in the industry. For this reason, several projects are being launched. The aim of the VALENTHIN project is to improve industrial energy efficiency by valorizing waste heat or by developing industrial processes. This thesis concentrates on the studies of valorization systems, particularly with regard to the different modeling methods. In this report, the bibliographies are synthesized, on the different models used for the valorization systems, especially the absorption system and the organic Rankine cycle mentioned in this project. Consequently, a modeling strategy is proposed and is shown for steady state simulations and dynamic regime systems. The choice of types of modeling must take into account their advantages and disadvantages and also the needs of the users, with the aim of modeling and developing systems more easily and efficiently.

Η παρούσα διπλωματική εργασία πραγματεύεται την μελέτη και ανάλυση ενός υψηλής τάξης μοντέλου διπλά τροφοδοτούμενης επαγωγικής μηχανής, κατάλληλο για μελέτες μεταβατικής κατάστασης αιολικών συστημάτων. Αρχικά, γίνεται μία εισαγωγή στις ανανεώσιμες πηγές ενέργειας, με ιδιαίτερη αναφορά στην αιολική ενέργεια. Κατόπιν, περιγράφονται οι διάφοροι τρόποι ταξινόμησης των ανεμογεννητριών που υπάρχουν σήμερα, τα δομικά στοιχεία αυτών, καθώς και η αεροδυναμική τους μετατροπή. Ακολουθεί η γενική παρουσίαση μίας διπλά τροφοδοτούμενης επαγωγικής γεννήτριας. Προκειμένου να γίνει μελέτη των μεταβατικών καταστάσεων, παρουσιάζεται το δυναμικό μοντέλο και ο διανυσματικός έλεγχος μίας διπλά τροφοδοτούμενης επαγωγικής γεννήτριας υψηλής τάξης. Εν συνεχεία, αναλύεται -βάσει εξισώσεων- η συμπεριφορά της εν λόγω γεννήτριας σε τριφασικές και ασύμμετρες βυθίσεις τάσεων, που είναι αποτέλεσμα διαφόρων μεταβατικών καταστάσεων. Τέλος, γίνεται η προσομοίωση ενός αιολικού πάρκου, που περιλαμβάνει ανεμογεννήτριες αυτού του τύπου και μελετώνται διάφορες διαταραχές στο σύστημα, όπως: συμμετρικά και ασύμμετρα βραχυκυκλώματα, απότομες μεταβολές της ταχύτητας του ανέμου, απώλεια και μεταβολή φορτίου. Η προσομοίωση πραγματοποιείται με τη βοήθεια του λογισμικού MATLAB/Simulink, έκδοση 7.6. / The subject of this thesis is the study and analysis of a high-order model of a doubly-fed induction machine (DFIM), suitable for unbalanced condition studies on a wind farm. At first, an introduction is made of the renewable energy sources, with special mention of the wind energy. Then, there is the description of the different types of wind turbines than exist nowadays, their components and their aerodynamic conversion. A general presentation of a doubly-fed induction generator (DFIG) is made and after that, for the study of disturbances, the dynamic model and the vector control of a high-order model of a doubly-fed induction generator are presented. Through mathematical equations, the performance of this generator under voltage dips is then described, result of various transition phenomena. Finally, the simulation of a wind farm that includes wind turbines of this type, is made and several disturbances on the grid, such as: symmetrical and asymmetrical faults, sudden changes of the wind speed, loss and change of the load. Simulation is made with the use of the software MATLAB/Simulink, version 7.6.

Two and three-wheeled vehicles are being used in increasing numbers in many emerging countries. The dynamics of such vehicles are very different from those of cars and other means of transportation. This thesis deals with a study of the dynamics of a motorcycle and an extensively used three-wheeled vehicle, called an “auto-rickshaw” in India. The commercially available multi-body dynamics (MBD) software, ADAMS, is used to model both the vehicles and simulations are performed to obtain insight into their dynamics. In the first part of the thesis, a study of the two wheeler dynamics is presented. A fairly detailed model of a light motorcycle with all the main sub-systems, such as the frame, front fork, shock absorbers , power train, brakes, front and rear wheel including tire slips and the rider is created in ADAMS-Motorcycle. The simulation results dealing with steering torques and angles for steady turns on a circular path are presented. From the simulation results and analytical models, it is shown that for path radius much greater than motorcycle wheel base, the steering torque and angle can be described by only two functions for each of the two variables. The first function is related to the lateral acceleration and can be determined numerically and the second function, in terms of the inverse of the path radius, is derived as an analytical approximation. Various tire and geometric parameters are varied in the ADAMS simulations and it is clearly shown that steady circular motion of a motorcycle can be reasonably approximated by only two curves–one for steering torque and one for steering angle. In the second part of the thesis, a stability analysis of the three-wheeled “autorickshaw” is presented. The steering instability is one of the major problems of the “auto-rickshaw” and this is studied using a MBD model created in ADAMS-CAR .In an Initial model the frame ,steering column and rear-forks (trailing arms) are assumed to be rigid. A linear eigenvalue analysis, at different speeds, reveals a predominantly steering oscillation, called a “wobble” mode, with a frequency in the range of 5 to 6Hz. The analysis results show that the damping of this mode is small but positive up to the maximum speed(14m/s) of the three-wheeled vehicle. Experiments performed on the three-wheeled vehicle show that the mode is unstable at speeds below 8.33m/s and thus the experimental results do not agree with the model. Next, this wobble instability is studied with an analytical model, similar to the model proposed for wheel shimmy problem in aircrafts. The results of this model show that the wobble is stable at low speeds regardless of the magnitude of torsional stiffness of steering column. This is also not matching with the experimental result. A more refined MBD model with flexibility incorporated in the frame, steering column and the trailing arm is constructed. Simulation results with the refined model show three modes of steering oscillations. Two of these are found to be well damped and the third is found to be lightly damped with negative damping at low speeds, and the results of the model with the flexibility is shown to be matching reasonably well with the experimental results. Detailed simulations with flexibility of each body incorporated, one at a time, show that the flexibility in the steering column is the main contributor of the steering instability and the instability is similar to the wheel shimmy problem in aircrafts. Finally, studies of modal interaction on steering instabilities and parametric studies with payload and trail are presented.

Cette thèse aborde les formalismes pour la modélisation multi-physique en support au cycle en V deconception. Ce travail a été réalisé dans le cadre du projet ANR–MoCoSyMec, selon la méthodologie duprototypage virtuel fonctionnel (PVF) et illustré sur des systèmes électromagnétiques.Nous nous sommes principalement intéressés au langage VHDL-AMS, en tant que support aux différentsniveaux de modélisation apparaissant dans le cycle en V de conception. Cela nous a conduits à traiter laportabilité et l’interopérabilité en VHDL-AMS de diverses méthodes et outils de modélisation. Nous avonsproposé et validé, via le formalisme des composants logiciels ICAr, des solutions aux limites de l’utilisation deVHDL-AMS pour modéliser certains phénomènes physiques reposants sur des calculs numériques.Nous avons étendu la norme ICAr pour supporter des modèles dynamiques décrits par des équationsdifférentielles algébriques (DAE) ; et pour des besoins de co-simulation, nous pouvons également y associer unsolveur. Ces développements sont désormais capitalisés dans le framework CADES.Enfin, nous avons proposé une architecture pour le portage de modèles d’un formalisme à un autre. Elle a étédéfinie et mise en oeuvre plus particulièrement pour des modèles magnétiques réluctants (Reluctool) et desMEMS magnétiques (MacMMems) vers le VHDL-AMS.Ces formalismes et méthodologies sont mis en oeuvre autour du PVF d’un contacteur électromagnétique. / This PhD report deals with modeling formalisms for multi-physical systems in the design V- cycle. Thiswork was carried out within the French ANR-MoCoSyMec project, according to the methodology of functionalvirtual prototyping (PVF) and illustrated with electromagnetical systems.The work focuses on the VHDL-AMS modeling language, as a support for several modeling levels appearingin the design V-cycle. In this work, the portability and interoperability problems have been studied, usingVHDL-AMS, for various modeling methods and tools. Solutions have been proposed and validated for use limitsof VHDL-AMS language, specifically for the modeling of some physical phenomena using numericalcomputations, through the software component formalism called ICAr.The ICAr software component standard has been extended to support dynamic models described throughdifferential algebraic equations (DAE). It has also been extended for co-simulation purposes in which a solver isassociated to the dynamic model inside the ICAr component. These developed solutions are now available in theframework CADES.Finally, architecture has been proposed for the transforming of models from a professional formalism intoanother, specifically into VHDL-AMS. It has been designed and implemented for reluctant magnetic models(RelucTool) and magnetic MEMS (MacMMems).These formalisms and methodologies are implemented around the functional virtual prototyping (PVF) of anelectromagnetic contactor.

Artificial human muscles have traditionally been operated through pneumatic means, and are known as Pneumatic Artificial Muscles (PAMs). Over the last several decades, Hydraulic Artificial Muscles (HAMs) have also been investigated due to their high power-to-weight ratio and human-like characteristics. Compared to PAMs, HAMs typically exhibit faster response, higher efficiency, and superior position control; characteristics which provide potential for application in rehabilitation robotics. This thesis presents a new approach to actuate artificial muscles in an antagonistic pair configuration. The detailed mechanical design of the test platform is introduced, along with the development of a dynamic model for actuating an artificial elbow joint. Also, custom manufactured Oil-based Hydraulic Artificial Muscles (OHAMs) are implemented in a biceps-triceps configuration and characterized on the test platform. Furthermore, an integrator-backstepping controller is derived for HAMs with different characteristics (stiffness and damping coefficients) in an antagonistic pair configuration. Finally, simulations and experimental results of the position control of the artificial elbow joint are discussed to confirm the functionality of the OHAMs utilizing the proposed actuating mechanism and the effectiveness of the developed control algorithm. / Graduate

Extracellular neuroelectronic interfacing has important applications in the fields of neural prosthetics, biological computation and whole-cell biosensing for drug screening and toxin detection. While the field of neuroelectronic interfacing holds great promise, the recording of high-fidelity signals from extracellular devices has long suffered from the problem of low signal-to-noise ratios and changes in signal shapes due to the presence of highly dispersive dielectric medium in the neuron-microelectrode cleft. This has made it difficult to correlate the extracellularly recorded signals with the intracellular signals recorded using conventional patch-clamp electrophysiology. For bringing about an improvement in the signalto-noise ratio of the signals recorded on the extracellular microelectrodes and to explore strategies for engineering the neuron-electrode interface there exists a need to model, simulate and characterize the cell-sensor interface to better understand the mechanism of signal transduction across the interface. Efforts to date for modeling the neuron-electrode interface have primarily focused on the use of point or area contact linear equivalent circuit models for a description of the interface with an assumption of passive linearity for the dynamics of the interfacial medium in the cell-electrode cleft. In this dissertation, results are presented from a nonlinear dynamic characterization of the neuroelectronic junction based on Volterra-Wiener modeling which showed that the process of signal transduction at the interface may have nonlinear contributions from the interfacial medium. An optimization based study of linear equivalent circuit models for representing signals recorded at the neuron-electrode interface subsequently iv proved conclusively that the process of signal transduction across the interface is indeed nonlinear. Following this a theoretical framework for the extraction of the complex nonlinear material parameters of the interfacial medium like the dielectric permittivity, conductivity and diffusivity tensors based on dynamic nonlinear Volterra-Wiener modeling was developed. Within this framework, the use of Gaussian bandlimited white noise for nonlinear impedance spectroscopy was shown to offer considerable advantages over the use of sinusoidal inputs for nonlinear harmonic analysis currently employed in impedance characterization of nonlinear electrochemical systems. Signal transduction at the neuron-microelectrode interface is mediated by the interfacial medium confined to a thin cleft with thickness on the scale of 20-110 nm giving rise to Knudsen numbers (ratio of mean free path to characteristic system length) in the range of 0.015 and 0.003 for ionic electrodiffusion. At these Knudsen numbers, the continuum assumptions made in the use of Poisson-Nernst-Planck system of equations for modeling ionic electrodiffusion are not valid. Therefore, a lattice Boltzmann method (LBM) based multiphysics solver suitable for modeling ionic electrodiffusion at the mesoscale neuron-microelectrode interface was developed. Additionally, a molecular speed dependent relaxation time was proposed for use in the lattice Boltzmann equation. Such a relaxation time holds promise for enhancing the numerical stability of lattice Boltzmann algorithms as it helped recover a physically correct description of microscopic phenomena related to particle collisions governed by their local density on the lattice. Next, using this multiphysics solver simulations were carried out for the charge relaxation dynamics of an electrolytic nanocapacitor with the intention of ultimately employing it for a simulation of the capacitive coupling between the neuron and the v planar microelectrode on a microelectrode array (MEA). Simulations of the charge relaxation dynamics for a step potential applied at t = 0 to the capacitor electrodes were carried out for varying conditions of electric double layer (EDL) overlap, solvent viscosity, electrode spacing and ratio of cation to anion diffusivity. For a large EDL overlap, an anomalous plasma-like collective behavior of oscillating ions at a frequency much lower than the plasma frequency of the electrolyte was observed and as such it appears to be purely an effect of nanoscale confinement. Results from these simulations are then discussed in the context of the dynamics of the interfacial medium in the neuron-microelectrode cleft. In conclusion, a synergistic approach to engineering the neuron-microelectrode interface is outlined through a use of the nonlinear dynamic modeling, simulation and characterization tools developed as part of this dissertation research.