In this work, we present mathematical and artistic techniques for the easy creation of artistic screening animations in video resolution by extending the artistic screening technique of adapting various patterns as screen dots for generating halftones. For video dithering, three different animations are needed. One is for screen dots which is a simple black and white animation; another is for the goal (or perceived) animation on the screen; and the other animation is for controlling the color and the size of screen dots. By combining three different animations with video dithering techniques, two animations appear simultaneously on the result video screen and provide complex and unique animation. Our techniques assure creating of aesthetic looking movies by providing frame to frame coherence and avoiding spatial and temporal aliasing that can be caused by low quality of video images. We shows how this technique is a powerful and effective way to create artistic results, by demonstrating variety of video dithering.

In this work, we present mathematical and artistic techniques for the easy creation of artistic screening animations in video resolution by extending the artistic screening technique of adapting various patterns as screen dots for generating halftones. For video dithering, three different animations are needed. One is for screen dots which is a simple black and white animation; another is for the goal (or perceived) animation on the screen; and the other animation is for controlling the color and the size of screen dots. By combining three different animations with video dithering techniques, two animations appear simultaneously on the result video screen and provide complex and unique animation. Our techniques assure creating of aesthetic looking movies by providing frame to frame coherence and avoiding spatial and temporal aliasing that can be caused by low quality of video images. We shows how this technique is a powerful and effective way to create artistic results, by demonstrating variety of video dithering.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / This paper presents an effective multi-layer background modeling method to detect moving objects by exploiting the advantage of novel distinctive features and hierarchical structure of the Codebook (CB) model. In the block-based structure, the mean-color feature within a block often does not contain sufficient texture information, causing incorrect classification especially in large block size layers. Thus, the Binary Ordered Dithering (BOD) feature becomes an important supplement to the mean RGB feature In summary, the uniqueness of this approach is the incorporation of the halftoning scheme with the codebook model for superior performance over the existing methods.

<p>Computer vision applications such as image classification and object detection often suffer from adversarial examples. For example, adding a small amount of noise to input images can trick the model into misclassification. Over the years, many defense mechanisms have been proposed, and different researchers have made seemingly contradictory claims on their effectiveness. This dissertation first presents an analysis of possible adversarial models and proposes an evaluation framework for comparing different more powerful and realistic adversary strategies. Then, this dissertation proposes two randomness-based defense mechanisms Random Spiking (RS) and MoNet to improve the robustness of image classifiers. Random Spiking generalizes dropout and introduces random noises in the training process in a controlled manner. MoNet uses the combination of secret randomness and Floyd-Steinberg dithering. Specifically, input images are first processed using Floyd-Steinberg dithering to reduce their color depth, and then the pixels are encrypted using the AES block cipher under a secret, random key. Evaluations under our proposed framework suggest RS and MoNet deliver better protection against adversarial examples than many existing schemes. Notably, MoNet significantly improves the resilience against transferability of adversarial examples, at the cost of a small drop in prediction accuracy. Furthermore, we extend the usage of MoNet to the object detection network and use it to align with model ensemble strategies (Affirmative and WBF (weighted fusion boxes)) and Test Time Augmentation (TTA). We call such a strategy 3MIX. Evaluations found that 3Mix can significantly improve the mean average precision (mAP) on both benign inputs and adversarial examples. In addition, 3Mix is a lightweight approach to migrate the adversarial examples without training new models.</p>

No description available.

Parmi les méthodes qui permettent de détecter des exoplanètes, la photométrie des transits est celle qui a connu le plus grand essor ces dernières années grâce à l’arrivée des télescopes spatiaux CoRoT (en 2006) puis Kepler (en 2009). Ces deux satellites ont permis de détecter des milliers de transits potentiellement planétaires. Étant donnés leur nombre et l’effort nécessaire à la confirmation de leur nature, il est essentiel d’effectuer, à partir des données photométriques, un classement efficace permettant d’identifier les transits les plus prometteurs et qui soit réalisable en un temps raisonnable. Pour ma thèse, j’ai développé un outil logiciel, rapide et automatisé, appelé BART (Bayesian Analysis for the Ranking of Transits) qui permet de réaliser un tel classement grâce une estimation de la probabilité que chaque transit soit de nature planétaire. Pour cela, mon outil s’appuie notamment sur le formalisme bayésien des probabilités et l’exploration de l’espace des paramètres libres par méthode de Monte Carlo avec des chaînes de Markov (mcmc).Une fois les exoplanètes détectées, l’étape suivante consiste à les caractériser. L’étude du système solaire nous a démontré, si cela était nécessaire, que l’information spectrale est un point clé pour comprendre la physique et l’histoire d’une planète. L’interférométrie annulante est une solution technologique très prometteuse qui pourrait permettre cela. Pour ma thèse, j’ai travaillé sur le banc optique Nulltimate afin d’étudier la faisabilité de certains objectifs technologiques liés à cette technique. Au-delà de la performance d’un taux d’extinction de 3,7.10^-5 en monochromatique et de 6,3.10^-4 en polychromatique dans l’infrarouge proche, ainsi qu’une stabilité de σN30 ms = 3,7.10^-5 estimée sur 1 heure, mon travail a permis d’assainir la situation en réalisant un budget d’erreur détaillé, une simulation en optique gaussienne de la transmission du banc et une refonte complète de l’informatique de commande. Tout cela m’a finalement permis d’identifier les faiblesses de Nulltimate. / From all exoplanet detection methods, transit photometry went through the quickest growth over the last few years thanks to the two space telescopes, CoRoT (in 2006) and Kepler (in 2009). These two satellites have identified thousands of potentially planetary transits. Given the number of detected transits and the effort required to demonstrate their natures, it is essential to perform, from photometric data only, a ranking allowing to efficiently identify the most promising transits within a reasonable period of time. For my thesis, I have developed a quick and automated software called bart (Bayesian Analysis for the Ranking of Transits) which realizes such a ranking thanks to the estimation of the probability regarding the planetary nature of each transit. For this purpose, I am relying on the Bayesian framework and free parameter space exploration with Markov Chain Monte Carlo (mcmc) methods.Once you have detected exoplanets, the following step is to characterise them. The study of the solar system demonstrated, if it was necessary, that the spectral information is a crucial clue for the understanding of the physics and history of a planet. Nulling interferometry is a promising solution which could make this possible. For my thesis, I worked on the optical bench Nulltimate in order to study the feasibility of certain technological requirements associated with this technique. Beyond the obtention of a nulling ratio of 3,7.10^-5 in monochromatic light and 6,3.10^-4 in polychromatic light in the near infrared, as well as a stability of σN30 ms = 3,7.10^-5 estimated on 1 hour, my work allowed to clarify the situation thanks to a detailed error budget, a simulation of the transmission based on Gaussian beam optics and a complete overhaul of the computer control system. All of this finally resulted in the identification of the weaknesses of Nulltimate.

This thesis presents a novel modulation scheme, called feedback dithering modulation, for DC to AC power converters. The feedback dithering modulator consists of a quantizer and a recently reported feedback dithering circuit, performing multilevel modulation with improved linearity and signal quality as opposed to the conventional modulation schemes. By combining the feedback dithering modulation and optimal control, a single-phase DC to AC power converter is built and tested. The resulting total harmonic distortion can be as low as 0.38% for a 25£[ load, or 0.47% when the output is open. Under the various operating conditions with DC voltages source varying from 190 V to 300 V and output powers from 0 to 600 W, the power converter always maintains a total harmonic distortion less than 1%, exhibiting high performance and excellent robustness.

The power density of a switching converter is dependent on the size of the power circuit components. Converters are operated in the hundreds of kHz to achieve high power density since the size of the converter reactive components decrease as frequency increases. Most present day low power (<200W) DC-DC converters operate at switching frequencies up to 500kHz. Some research has been conducted on converters that can operate above 500kHz up to 4MHz. In the near future, most DC-DC switching converters for communications and computers will operate at switching frequencies of 1-10MHz in order to achieve greater power density and improved transient response. To meet the next generation requirements of these applications, four new ideas are proposed in this thesis. The first contribution is a new current source gate drive circuit for power MOSFETs. The circuit provides a nearly constant gate current to reduce switching transition times and therefore switching loss in power MOSFETs. In addition, it can recover a portion of the gate energy normally dissipated in a conventional driver. Demonstrated loss reduction of 24.8% at 10V/5A load are presented in comparison to a conventional voltage source driver for a boost converter switching at 1MHz. The second contribution is a new high efficiency 1MHz synchronous buck voltage regulator using an improved current source driver. The proposed circuit achieves short rise and fall times to reduce switching loss in the buck HS MOSFET. It also recovers a portion of the SR gate energy, enabling a loss reduction of 24% at 1.3V/30A load in comparison to a conventional driver. In the third contribution, a new switching loss model is proposed for synchronous buck voltage regulators. The model uses simple closed form equations to calculate the rise and fall times and piecewise linear approximations of the HS MOSFET voltage and current waveforms to allow quick and accurate calculation of switching loss. The final contribution is a new variable frequency digital control method for resonant converters, which is suitable for future applications switching at 10MHz. The proposed method uses frequency dithering to reduce the clock frequency demands of the digital controller. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2008-02-28 10:56:06.732

This thesis describes summarizing and comparsion of advanced dithering techniques used to reduce the image color space on n-dimensional palette. The goal is to create a set of basic methods including theirs enhancements and modifications focusing on the output image quality and maximum visual fidelity to the original image. Another part of this thesis is to analyze this methods using own comparsing method and design new dithering algorithm combining their advantages.

Compact architectures, ternary weights and binary activations are two methods suitable for making neural networks more efficient. We introduce a) a dithering binary activation which improves accuracy of ternary weight networks with binary activations by randomizing quantization error, and b) a method of implementing ternary weight networks with binary activations using binary operations. Despite these new approaches, training a compact SqueezeNet architecture with ternary weights and full precision activations on ImageNet degrades classification accuracy significantly more than when training a less compact architecture the same way. Therefore ternary weights in their current form cannot be called the best method for reducing network size. However, the effect of weight decay on ternary weight network training should be investigated more in order to have more certainty in this finding. / Kompakta arkitekturer, ternära vikter och binära aktiveringar är två metoder som är lämpliga för att göra neurala nätverk effektivare. Vi introducerar a) en dithering binär aktivering som förbättrar noggrannheten av ternärviktsnätverk med binära aktiveringar genom randomisering av kvantiseringsfel, och b) en metod för genomförande ternärviktsnätverk med binära aktiveringar med användning av binära operationer. Trots dessa nya metoder, att träna en kompakt SqueezeNet-arkitektur med ternära vikter och fullprecisionaktiveringar på ImageNet försämrar klassificeringsnoggrannheten betydligt mer än om man tränar en mindre kompakt arkitektur på samma sätt. Därför kan ternära vikter i deras nuvarande form inte kallas bästa sättet att minska nätverksstorleken. Emellertid, effekten av weight decay på träning av ternärviktsnätverk bör undersökas mer för att få större säkerhet i detta resultat.