We discuss numerical methods for the stabilization of large linear multi-input control systems of the form x=Ax + Bu via a feedback of the form u=Fx. The method discussed in this paper is a stabilization algorithm that is based on subspace splitting. This splitting is done via the matrix sign-function method. Then a projection into the unstable subspace is performed followed by a stabilization technique via the solution of an appropriate algebraic Riccati equation. There are several possibilities to deal with the freedom in the choice of the feedback as well as in the cost functional used in the Riccati equation. We discuss several optimality criteria and show that in special cases the feedback matrix F of minimal spectral norm is obtained via the Riccati equation with the zero constant term. A theoretical analysis about the distance to instability of the closed loop system is given and furthermore numerical examples are presented that support the practical experience with this method.

High efficiency of power converters placed between renewable energy sources and the utility grid is required to maximize the utilization of these sources. Power quality is another aspect that requires large passive elements (inductors, capacitors) to be placed between these sources and the grid. The main objective is to develop higher-level high frequency-based power converter system (HFPCS) that optimizes the use of hybrid renewable power injected into the power grid. The HFPCS provides high efficiency, reduced size of passive components, higher levels of power density realization, lower harmonic distortion, higher reliability, and lower cost. The dynamic modeling for each part in this system is developed, simulated and tested. The steady-state performance of the grid-connected hybrid power system with battery storage is analyzed. Various types of simulations were performed and a number of algorithms were developed and tested to verify the effectiveness of the power conversion topologies. A modified hysteresis-control strategy for the rectifier and the battery charging/discharging system was developed and implemented. A voltage oriented control (VOC) scheme was developed to control the energy injected into the grid. The developed HFPCS was compared experimentally with other currently available power converters. The developed HFPCS was employed inside a microgrid system infrastructure, connecting it to the power grid to verify its power transfer capabilities and grid connectivity. Grid connectivity tests verified these power transfer capabilities of the developed converter in addition to its ability of serving the load in a shared manner. In order to investigate the performance of the developed system, an experimental setup for the HF-based hybrid generation system was constructed. We designed a board containing a digital signal processor chip on which the developed control system was embedded. The board was fabricated and experimentally tested. The system’s high precision requirements were verified. Each component of the system was built and tested separately, and then the whole system was connected and tested. The simulation and experimental results confirm the effectiveness of the developed converter system for grid-connected hybrid renewable energy systems as well as for hybrid electric vehicles and other industrial applications.

L’objectif principal de cette thèse est de développer une méthodologie qui permette de définir des sollicitations simplifiées représentatives des sollicitations réelles rencontrées en exploitation, c’est-à-dire équivalentes en sévérité vis-à-vis du phénomène d’amorçage de fissure par fatigue mécanique. Cette méthodologie doit être adaptée aux problèmes multi-paramètres car les sollicitations subies par les roues ferroviaires sont multidimensionnelles (chargement vertical et latéral) et indépendantes. Enfin, la thèse vise aussi à proposer une approche fiabiliste globale du problème de fatigue des roues, qui pourra être une extension de la méthode Contrainte-Résistance aux cas des sollicitations multi-entrée. Un critère de fatigue pour l’acier des roues est identifié à partir des nouveaux essais. / The main objective of this PHD thesis is to develop a method for the definition of simplified equivalent loads representative of real loads (the severity is equivalent from fatigue phenomenon point of view). This method must be adapted to multi-input problems because loads applied on wheels are multi-dimensional (vertical and lateral loads) and independent. Finally, the thesis also aims to provide a comprehensive approach to fatigue-reliability problem of the wheels, which can be an extension of the stress-strength method for multi-input loads. A fatigue criterion for the railway will is presented and identified using a new test campaign.

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Anomaly event detection has become increasingly important and is of great significance for real-time monitoring systems. However, developing a reliable anomaly detection and localization model still requires overcoming many challenging problems considering the ambiguity in the definition of an abnormal event and the lack of ground truth datasets for training. In this thesis, we propose a Two-way Multi-input Generative Neural Network (TMGNN), which is an unsupervised anomaly events detection and localization method based on Generative Adversarial Network (GAN). TMGNN is composed of two neural networks, an appearance generation neural network and a motion generation neural network. These two networks are trained on normal frames and their corresponding motion and mosaic frames respectively. In the testing steps, the trained model cannot properly reconstruct the anomalous objects since the network is trained only on normal frames and has not learned patterns of anomalous cases. With the help of our new patch-based evaluation method, we utilize the reconstruction error to detect and localize possible anomalous objects. Our experiments show that on the UCSD Pedestrain2 dataset, our approach achieves 96.5% Area Under Curve (AUC) and 94.1% AUC for the frame-level and pixel-level criteria, respectively, reaching the best classification results compared to other traditional and deep learning methods. / Thesis / Master of Applied Science (MASc) / Recently, abnormal event detection has attracted increasing attention in the field of surveillance video. However, it is still a big challenge to build an automatic and reliable abnormal event detection system to review a surveillance video containing hundreds of frames and mask the frames with abnormal objects or events. In this thesis, we build a model and teach it to memorize the structure of normal frames. Then the model is able to tell which frames are normal. Any other frames that appear in the surveillance video will be classified as abnormal frames. Moreover, we design a new method to evaluate the performance of our model and compare it with other models’ results.

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Yes / An adaptive iterative learning control(ILC) approach is proposed for a class of multi-input multi-output (MIMO) uncertain nonlinear systems without prior knowledge about system control gain matrices. The Nussbaum-type gain and the positive definite discrete matrix kernel are proposed for dealing with selection of the unknown control gain and learning of the repeatable uncertainties, respectively. Asymptotic convergence for a trajectory tracking within a finite time interval is achieved through repetitive tracking. Simulations are carried out to show the validity of the proposed control method.

Adaptive feedforward control of any physical system, acoustical, vibrational or other, requires what is termed as an uncontrollable coherent reference signal. That is, a signal which is highly representative (coherent) of the disturbance to be controlled which is not affected by the control actuator itself. Creating the <i>coherent</i> portion of this requirement for a certain class of problems is the motivation of this work. Most physical disturbances do not originate from a single source, but rather maintain contributions from a number of (possibly) correlated paths. For engineers who have access to only a single-input single-output (SISO) adaptive controller, the multi-source disturbance presents a difficult design issue. Simply adding the references in a linear combination can result in a signal which is not coherent at any frequency. Appropriately amplifying and suppressing coherent and incoherent signals prior to their linear combination can result in a signal which accurately represents the disturbance at all frequencies. This is precisely the task that the newly developed coherent output power (COP) filters perform. By calculating the coherent (or partial coherent) output power of each of the candidate references before control occurs, frequency domain filters are designed to remove incoherent portions of each signal. The advantages of performing the COP filtering procedure are very apparent when compared to the simple linear combination of signals. Coherence, and thus control performance, can be drastically improved. The COP filtering technique offers a means for system identification and computational savings not apparent in the conventional adaptive array, which solves the same multi-source problem. / Master of Science

abstract: Static CMOS logic has remained the dominant design style of digital systems for more than four decades due to its robustness and near zero standby current. Static CMOS logic circuits consist of a network of combinational logic cells and clocked sequential elements, such as latches and flip-flops that are used for sequencing computations over time. The majority of the digital design techniques to reduce power, area, and leakage over the past four decades have focused almost entirely on optimizing the combinational logic. This work explores alternate architectures for the flip-flops for improving the overall circuit performance, power and area. It consists of three main sections. First, is the design of a multi-input configurable flip-flop structure with embedded logic. A conventional D-type flip-flop may be viewed as realizing an identity function, in which the output is simply the value of the input sampled at the clock edge. In contrast, the proposed multi-input flip-flop, named PNAND, can be configured to realize one of a family of Boolean functions called threshold functions. In essence, the PNAND is a circuit implementation of the well-known binary perceptron. Unlike other reconfigurable circuits, a PNAND can be configured by simply changing the assignment of signals to its inputs. Using a standard cell library of such gates, a technology mapping algorithm can be applied to transform a given netlist into one with an optimal mixture of conventional logic gates and threshold gates. This approach was used to fabricate a 32-bit Wallace Tree multiplier and a 32-bit booth multiplier in 65nm LP technology. Simulation and chip measurements show more than 30% improvement in dynamic power and more than 20% reduction in core area. The functional yield of the PNAND reduces with geometry and voltage scaling. The second part of this research investigates the use of two mechanisms to improve the robustness of the PNAND circuit architecture. One is the use of forward and reverse body biases to change the device threshold and the other is the use of RRAM devices for low voltage operation. The third part of this research focused on the design of flip-flops with non-volatile storage. Spin-transfer torque magnetic tunnel junctions (STT-MTJ) are integrated with both conventional D-flipflop and the PNAND circuits to implement non-volatile logic (NVL). These non-volatile storage enhanced flip-flops are able to save the state of system locally when a power interruption occurs. However, manufacturing variations in the STT-MTJs and in the CMOS transistors significantly reduce the yield, leading to an overly pessimistic design and consequently, higher energy consumption. A detailed analysis of the design trade-offs in the driver circuitry for performing backup and restore, and a novel method to design the energy optimal driver for a given yield is presented. Efficient designs of two nonvolatile flip-flop (NVFF) circuits are presented, in which the backup time is determined on a per-chip basis, resulting in minimizing the energy wastage and satisfying the yield constraint. To achieve a yield of 98%, the conventional approach would have to expend nearly 5X more energy than the minimum required, whereas the proposed tunable approach expends only 26% more energy than the minimum. A non-volatile threshold gate architecture NV-TLFF are designed with the same backup and restore circuitry in 65nm technology. The embedded logic in NV-TLFF compensates performance overhead of NVL. This leads to the possibility of zero-overhead non-volatile datapath circuits. An 8-bit multiply-and- accumulate (MAC) unit is designed to demonstrate the performance benefits of the proposed architecture. Based on the results of HSPICE simulations, the MAC circuit with the proposed NV-TLFF cells is shown to consume at least 20% less power and area as compared to the circuit designed with conventional DFFs, without sacrificing any performance. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

We discuss numerical methods for the stabilization of large linear multi-input control systems of the form x=Ax + Bu via a feedback of the form u=Fx. The method discussed in this paper is a stabilization algorithm that is based on subspace splitting. This splitting is done via the matrix sign-function method. Then a projection into the unstable subspace is performed followed by a stabilization technique via the solution of an appropriate algebraic Riccati equation. There are several possibilities to deal with the freedom in the choice of the feedback as well as in the cost functional used in the Riccati equation. We discuss several optimality criteria and show that in special cases the feedback matrix F of minimal spectral norm is obtained via the Riccati equation with the zero constant term. A theoretical analysis about the distance to instability of the closed loop system is given and furthermore numerical examples are presented that support the practical experience with this method.