Design and analysis of ripple-based controls based on the discrete modeling and Floquet theory

Ripple-based controls can strongly reduce the required output capacitance in PowerSoC converter thanks to a very fast dynamic response. Unfortunately, these controls are prone to sub-harmonic oscillations and several parameters affect the stability of these systems. This paper derives and validates a simulation-based modeling and stability analysis of a closed-loop V 2Ic control applied to a 5 MHz Buck converter using discrete modeling and Floquet theory to predict stability. This allows the derivation of sensitivity analysis to design robust systems. The work is extended to different V 2 architectures using the same methodology.

Cooperative Multi-robot Patrolling: A study of distributed approaches based on mathematical models of game theory to protect infrastructures

El principio de Teoría de Juegos permite desarrollar modelos estocásticos de patrullaje multi-robot para proteger infraestructuras criticas. La protección de infraestructuras criticas representa un gran reto para los países al rededor del mundo, principalmente después de los ataques terroristas llevados a cabo la década pasada. En este documento el termino infraestructura hace referencia a aeropuertos, plantas nucleares u otros instalaciones. El problema de patrullaje se define como la actividad de patrullar un entorno determinado para monitorear cualquier actividad o sensar algunas variables ambientales. En esta actividad, un grupo de robots debe visitar un conjunto de puntos de interés definidos en un entorno en intervalos de tiempo irregulares con propósitos de seguridad. Los modelos de partullaje multi-robot son utilizados para resolver este problema. Hasta el momento existen trabajos que resuelven este problema utilizando diversos principios matemáticos. Los modelos de patrullaje multi-robot desarrollados en esos trabajos representan un gran avance en este campo de investigación. Sin embargo, los modelos con los mejores resultados no son viables para aplicaciones de seguridad debido a su naturaleza centralizada y determinista. Esta tesis presenta cinco modelos de patrullaje multi-robot distribuidos e impredecibles basados en modelos matemáticos de aprendizaje de Teoría de Juegos. El objetivo del desarrollo de estos modelos está en resolver los inconvenientes presentes en trabajos preliminares. Con esta finalidad, el problema de patrullaje multi-robot se formuló utilizando conceptos de Teoría de Grafos, en la cual se definieron varios juegos en cada vértice de un grafo. Los modelos de patrullaje multi-robot desarrollados en este trabajo de investigación se han validado y comparado con los mejores modelos disponibles en la literatura. Para llevar a cabo tanto la validación como la comparación se ha utilizado un simulador de patrullaje y un grupo de robots reales. Los resultados experimentales muestran que los modelos de patrullaje desarrollados en este trabajo de investigación trabajan mejor que modelos de trabajos previos en el 80% de 150 casos de estudio. Además de esto, estos modelos cuentan con varias características importantes tales como distribución, robustez, escalabilidad y dinamismo. Los avances logrados con este trabajo de investigación dan evidencia del potencial de Teoría de Juegos para desarrollar modelos de patrullaje útiles para proteger infraestructuras. ABSTRACT Game theory principle allows to developing stochastic multi-robot patrolling models to protect critical infrastructures. Critical infrastructures protection is a great concern for countries around the world, mainly due to terrorist attacks in the last decade. In this document, the term infrastructures includes airports, nuclear power plants, and many other facilities. The patrolling problem is defined as the activity of traversing a given environment to monitoring any activity or sensing some environmental variables If this activity were performed by a fleet of robots, they would have to visit some places of interest of an environment at irregular intervals of time for security purposes. This problem is solved using multi-robot patrolling models. To date, literature works have been solved this problem applying various mathematical principles.The multi-robot patrolling models developed in those works represent great advances in this field. However, the models that obtain the best results are unfeasible for security applications due to their centralized and predictable nature. This thesis presents five distributed and unpredictable multi-robot patrolling models based on mathematical learning models derived from Game Theory. These multi-robot patrolling models aim at overcoming the disadvantages of previous work. To this end, the multi-robot patrolling problem was formulated using concepts of Graph Theory to represent the environment. Several normal-form games were defined at each vertex of a graph in this formulation. The multi-robot patrolling models developed in this research work have been validated and compared with best ranked multi-robot patrolling models in the literature. Both validation and comparison were preformed by using both a patrolling simulator and real robots. Experimental results show that the multirobot patrolling models developed in this research work improve previous ones in as many as 80% of 150 cases of study. Moreover, these multi-robot patrolling models rely on several features to highlight in security applications such as distribution, robustness, scalability, and dynamism. The achievements obtained in this research work validate the potential of Game Theory to develop patrolling models to protect infrastructures.

Environmental Wireless Sensor Network Deployment in Food Industry: from Theory to Practice

The difficulty behind Wireless Sensor Network deployments in industrial environments not only resides in the number of nodes or the communication protocols but also in the real location of the sensor nodes and the parameters to be monitored. Sensor soiling, high humidity and unreachable locations, among others, make real deployments a very difficult task to plan. Even though it is possible to find myriad approaches for floor planners and deployment tools in the state of the art, most of these problems are very difficult to model and foresee before actually deploying the network in the final scenario. This work shows two real deployments in food factories and how their problems are found and overcome.

Cancellation zone in supersonic lifting wing theory

BASING their work on a linear theory, Evvard1 and Krasilshchikova2'3 independently developed an expression that yields the perturbation generated by a thiri lifting wing of arbitrary planform flying at supersonic speed on a point placed on the wing plane inside its planform,1 or both on and above the wing plane.2 This point must be influenced by two leading edges, one supersonic and the other partially subsonic. Although these authors followed different approaches, their methods concur in showing the existence of a perfectly defined cancellation zone. In this Note, the Evvard approach is generalized to the case solved by Krasilshchikova. Circumventing the latter's lengthy and somewhat complex approach, Evvard's simple method seems to be useful at least for educational purposes.

On multiple-path sonic anemometer measurement theory

In this paper, a model of the measuring process of sonic anemometers with more than one measuring path is presented. The main hypothesis of the work is that the time variation of the turbulent speed field during the sequence of pulses that produces a measure of the wind speed vector affects the measurement. Therefore, the previously considered frozen flow, or instantaneous averaging, condition is relaxed. This time variation, quantified by the mean Mach number of the flow and the time delay between consecutive pulses firings, in combination with both the full geometry of sensors (acoustic path location and orientation) and the incidence angles of the mean with speed vector, give rise to significant errors in the measurement of turbulence which are not considered by models based on the hypothesis of instantaneous line averaging. The additional corrections (relative to the ones proposed by instantaneous line-averaging models) are strongly dependent on the wave number component parallel to the mean wind speed, the time delay between consecutive pulses, the Mach number of the flow, the geometry of the sensor and the incidence angles of mean wind speed vector. Kaimal´s limit k W1=1/l (where k W1 is the wave number component parallel to mean wind speed and l is the path length) for the maximum wave numbers from which the sonic process affects the measurement of turbulence is here generalized as k W1=C l /l, where C l is usually lesser than unity and depends on all the new parameters taken into account by the present model.

Galectin-4 and Small Intestinal Brush Border Enzymes Form Clusters

Detergent-insoluble complexes prepared from pig small intestine are highly enriched in several transmembrane brush border enzymes including aminopeptidase N and sucrase-isomaltase, indicating that they reside in a glycolipid-rich environment in vivo. In the present work galectin-4, an animal lectin lacking a N-terminal signal peptide for membrane translocation, was discovered in these complexes as well, and in gradient centrifugation brush border enzymes and galectin-4 formed distinct soluble high molecular weight clusters. Immunoperoxidase cytochemistry and immunogold electron microscopy showed that galectin-4 is indeed an intestinal brush border protein; we also localized galectin-4 throughout the cell, mainly associated with membraneous structures, including small vesicles, and to the rootlets of microvillar actin filaments. This was confirmed by subcellular fractionation, showing about half the amount of galectin-4 to be in the microvillar fraction, the rest being associated with insoluble intracellular structures. A direct association between the lectin and aminopeptidase N was evidenced by a colocalization along microvilli in double immunogold labeling and by the ability of an antibody to galectin-4 to coimmunoprecipitate aminopeptidase N and sucrase-isomaltase. Furthermore, galectin-4 was released from microvillar, right-side-out vesicles as well as from mucosal explants by a brief wash with 100 mM lactose, confirming its extracellular localization. Galectin-4 is therefore secreted by a nonclassical pathway, and the brush border enzymes represent a novel class of natural ligands for a member of the galectin family. Newly synthesized galectin-4 is rapidly “trapped” by association with intracellular structures prior to its apical secretion, but once externalized, association with brush border enzymes prevents it from being released from the enterocyte into the intestinal lumen.

Unifying theory of hypoxia tolerance: molecular/metabolic defense and rescue mechanisms for surviving oxygen lack.

We develop a unifying theory of hypoxia tolerance based on information from two cell level models (brain cortical cells and isolated hepatocytes) from the highly anoxia tolerant aquatic turtle and from other more hypoxia sensitive systems. We propose that the response of hypoxia tolerant systems to oxygen lack occurs in two phases (defense and rescue). The first lines of defense against hypoxia include a balanced suppression of ATP-demand and ATP-supply pathways; this regulation stabilizes (adenylates) at new steady-state levels even while ATP turnover rates greatly decline. The ATP demands of ion pumping are down-regulated by generalized "channel" arrest in hepatocytes and by "spike" arrest in neurons. Hypoxic ATP demands of protein synthesis are down-regulated probably by translational arrest. In hypoxia sensitive cells this translational arrest seems irreversible, but hypoxia-tolerant systems activate "rescue" mechanisms if the period of oxygen lack is extended by preferentially regulating the expression of several proteins. In these cells, a cascade of processes underpinning hypoxia rescue and defense begins with an oxygen sensor (a heme protein) and a signal-transduction pathway, which leads to significant gene-based metabolic reprogramming-the rescue process-with maintained down-regulation of energy-demand and energy-supply pathways in metabolism throughout the hypoxic period. This recent work begins to clarify how normoxic maintenance ATP turnover rates can be drastically (10-fold) down-regulated to a new hypometabolic steady state, which is prerequisite for surviving prolonged hypoxia or anoxia. The implications of these developments are extensive in biology and medicine.

Persisting to Graduation: A Grounded Theory Exploration of Nontraditional Undergraduate Women's Enrollment

While women maintain a numerical majority in undergraduate college enrollments and degrees earned, they also represent the numerical majority among students over 29 years old, students of color, students who are in the lowest income category, students who are single parents, and students who attend college part-time (Peter & Horn, 2005; Planty, et al., 2008). The National Center for Educational Statistics (NCES) has identified seven characteristics that place students at risk of not completing an undergraduate degree; (a) delayed enrollment between high school and college, (b) part-time enrollment, (c) financial independence, (d) students with dependents, (e) students who are single parents, (f) students who work full-time while enrolled, and (g) students who completed a GED as opposed to earning a high school diploma (Choy, 2002; Dickerson & Stiefer, 2006; Horn & Premo, 1995). The above characteristics overlap with the categories where women have a numerical majority, thereby placing women in greater jeopardy of not completing a bachelor's degree. A review of the existing persistence literature demonstrates a lack of research devoted to understanding the persistence experiences, challenges, strategies, and decisions of nontraditional undergraduate in favor of the "traditional" undergraduate student (Pascarella & Terenzini, 2005; Reason 2003). For this doctoral dissertation, I have based the research on a critical race feminist framework, informed by my experience working with the population of nontraditional undergraduate women at a women's college and employed a critique of the persistence literature as sensitizing concepts. Using a modified grounded theory research design, I collected and analyzed data which led to the development of a grounded theory of nontraditional undergraduate women's persistence. The emergent concepts of commitment, environment, and support interact in a theory of academic momentum and I offer a critical race feminist reading of the findings and theory to expose race neutrality, honor the voices of women of color, and deconstruct the evidence presented. The implications of this research include student, institutional, and inclusive excellence approaches to increasing the persistence of nontraditional undergraduate women and contribute to the success of this unique population of learners.

Taking The 'Sport' Out of Sports Parenting: Toward A Theory of Sport Related Parent-Child Communication Competency

Research has shown that over-emphasis on winning is the number one reason why approximately seventy percent of the forty million children who participate in youth sports will quit by age 13. This study utilized a constructivist grounded theory approach to investigate the role of parent-child communication within the context of youth sports. A total of 22 athletes and 20 parents were recruited through a Western university to discuss messages exchanged during youth sport participation. The results suggest that the delineation between messages of support and pressure is largely dependent on discursive work done by both parent and child. Parents who employed competent communicative strategies to avoid miscommunications regarding participation and sports goals were able to provide support and strengthen the relationship despite pressurized situations. The present study frames the youth sport dilemma within a developing conceptualization of communicative (in)competence and offers theoretical implications for sport related parent-child communication competency (SRPCCC).

Monetary Effervescence: A Sociological Theory of Religion Applied to Money

This project attempts to answer the question "What holds the construction of money together?" by asserting that it is money's religious nature which provides the moral compulsion for people to use, and continue to uphold, money as a socially constructed concept. This project is primarily descriptive and focuses on the religious nature of money by employing a sociological theory of religion in viewing money as a technical concept. This is an interdisciplinary work between religious studies, economics, and sociology and draws heavily from Emile Durkheim's 'The Elementary Forms of Religious Life' as well as work related to heterodox theories of money developed by Geoffrey Ingham, A. Mitchell Innes, and David Graeber. Two new concepts are developed: the idea of monetary sacrality and monetary effervescence, both of which serve to recharge the religious saliency of money. By developing the concept of monetary sacrality, this project shows how money acts to interpret our economic relations while also obfuscating complex power dynamics in society, making them seem naturally occurring and unchangeable. The project also shows how our contemporary fractional reserve banking system contributes to money's collective effervescence and serves to animate economic acting within a monetary network. The project concludes by outlining multiple implications for religious studies, economics, sociology, and central banking.

CB-norm estimates for maps between noncommutative Lp-spaces and quantum channel theory.

In the first part of this work, we show how certain techniques from quantum information theory can be used in order to obtain very sharp embeddings between noncommutative Lp-spaces. Then, we use these estimates to study the classical capacity with restricted assisted entanglement of the quantum erasure channel and the quantum depolarizing channel. In particular, we exactly compute the capacity of the first one and we show that certain nonmultiplicative results hold for the second one.

Restaurant Health and Hygiene: A Model Program with Theory-Based Guidelines for Implementation

Poor hygienic practices and illness of restaurant employees are major contributors to the contamination of food and the occurrence of food-borne illness in the United States, costing the food industry and society billions of dollars each year. Risk factors associated with this problem include lack of proper handwashing; food handlers reporting to work sick; poor personal hygiene; and bare hand contact with ready-to-eat foods. However, traditional efforts to control these causes of food-borne illness by public health authorities have had limited impact, and have revealed the need for comprehensive and innovative programs that provide active managerial control over employee health and hygiene in restaurant establishments. Further, the introduction and eventual adoption by the food industry of such programs can be facilitated through the use of behavior-change theory. This Capstone Project develops a model program to assist restaurant owners and operators in exerting active control over health and hygiene in their establishments and provides theory-based recommendations for the introduction of the program to the food industry.

Tourism dependence and host community perceptions: notes on the social exchange theory

This article examines the opinions of the local population on the south coast of the Spanish province of Alicante regarding the development of tourism in recent years, analysing their perception of the benefits of tourism using the social exchange theory. This study is presented in two stages. The qualitative stage, which is based on in-depth interviews and focus groups, acts as a guide for the second stage, which consists of a survey conducted with the resident Spanish population. It was found that people linked to the tourist sector through their work view tourism as the driving force behind the economic and social development of their towns, although they are more critical than others of the model that has been established. They defend the development process that has taken place, but feel that overcrowding brings their towns to a standstill and needs to be resolved.

Microscopic theory for quantum mirages in quantum corrals

Scanning tunneling microscopy permits us to image the Kondo resonance of a single magnetic atom adsorbed on a metallic surface. When the magnetic impurity is placed at the focus of an elliptical quantum corral, a Kondo resonance has been recently observed both on top of the impurity and on top of the focus where no magnetic impurity is present. This projection of the Kondo resonance to a remote point on the surface is referred to as quantum mirage. We present a quantum mechanical theory for the quantum mirage inside an ideal quantum corral and predict that the mirage will occur in corrals with shapes other than elliptical.

Cotunneling theory of atomic spin inelastic electron tunneling spectroscopy

We propose cotunneling as the microscopic mechanism that makes possible inelastic electron tunneling spectroscopy of magnetic atoms in surfaces for a wide range of systems, including single magnetic adatoms, molecules, and molecular stacks. We describe electronic transport between the scanning tip and the conducting surface through the magnetic system (MS) with a generalized Anderson model, without making use of effective spin models. Transport and spin dynamics are described with an effective cotunneling Hamiltonian in which the correlations in the magnetic system are calculated exactly and the coupling to the electrodes is included up to second order in the tip MS and MS substrate. In the adequate limit our approach is equivalent to the phenomenological Kondo exchange model that successfully describes the experiments. We apply our method to study in detail inelastic transport in two systems, stacks of cobalt phthalocyanines and a single Mn atom on Cu2N. Our method accounts for both the large contribution of the inelastic spin exchange events to the conductance and the observed conductance asymmetry.