Developing Model-Based Design Evaluation for Pipelined A/D Converters

This paper deals with a prospective approach of modeling, design evaluation and error determination applied to pipelined A/D converter architecture. In contrast with conventional ADC modeling algorithms targeted to extract the maximum ADC non-linearity error, the innovative approach presented allows to decompose magnitudes of individual error sources from a measured or simulated response of an ADC device. Design Evaluation methodology was successfully applied to Nyquist rate cyclic converters in our works [13]. Now, we extend its principles to pipelined architecture. This qualitative decomposition can significantly contribute to the ADC calibration procedure performed on the production line in term of integral and differential nonlinearity. This is backgrounded by the fact that the knowledge of ADC performance contributors provided by the proposed method helps to adjust the values of on-chip converter components so as to equalize (and possibly minimize) the total non-linearity error. In this paper, the design evaluation procedure is demonstrated on a system design example of pipelined A/D converter. Significant simulation results of each stage of the design evaluation process are given, starting from the INL performance extraction proceeded in a powerful Virtual Testing Environment implemented in Maple™ software and finishing by an error source simulation, modeling of pipelined ADC structure and determination of error source contribution, suitable for a generic process flow

Statistics of the dissipated energy in driven single-electron transitions

We analyze the distribution of heat generated in driven single-electron transitions and discuss the related non-equilibrium work theorems. In the adiabatic limit, the heat distribution is shown to become Gaussian, with the heat noise that, in spite of thermal fluctuations, vanishes together with the average dissipated energy. We show that the transitions satisfy Jarzynski equality for arbitrary drive and calculate the probability of the negative heat values. We also derive a general condition on the heat distribution that generalizes the Bochkov-Kuzovlev equality and connects it to the Jarzynski equality.Comment: 5 pages, 2 figure

Using Leap Motion to create a physically interactive musical interface

Nowadays, we can easily find among us more and more electronical devices that a few years ago, were only feasible in science fiction: Augmented reality glasses, smart watches, autonomous cars… It is hard to deny that we're living in an age of astounding technological breakthroughs, where each day brings new advancements, and progress is faster than ever. This project aims to contribute to the aforementioned progress, focusing in a recent technology: the motion tracking device called Leap Motion, not only by exploring its virtual object interaction capabilities, but pushing its limits to allow physical interaction with real-world objects. The final goal of this project, and its contribution to this field, is the creation of a musical device that uses the Leap Motion technology to provide an environment where users can interact with physical elements to play with music.Hoy en día, podemos encontrar entre nosotros cada vez más dispositivos electrónicos que hace unos años sólo eran factibles en la ciencia ficción: gafas de realidad aumentada, relojes inteligentes, automóviles autónomos ... Es difícil negar que estamos viviendo en una época de asombrosos avances tecnológicos, donde cada día trae nuevos avances, y el progreso es más rápido que nunca. Este proyecto pretende contribuir al progreso mencionado, centrándose en una tecnología reciente: el dispositivo de seguimiento de movimiento llamado Leap Motion, no sólo explorando sus capacidades de interacción de objetos virtuales, sino empujando sus límites para permitir la interacción física con objetos del mundo real. El objetivo final de este proyecto, y su contribución a este campo, es la creación de un dispositivo musical que utiliza la tecnología Leap Motion para proporcionar un entorno donde los usuarios puedan interactuar con elementos físicos para jugar con la música.Avui dia, podem trobar fàcilment entre nosaltres cada vegada més dispositius electrònics que fa uns anys eren només factibles en la ciència ficció: ulleres de realitat augmentada, rellotges intel·ligents, vehicles autònoms ... És difícil negar que estem vivint en una època de sorprenents avenços tecnològics, on cada dia porta nous avenços, i el progrés és més ràpid que mai. Aquest projecte té com a objectiu contribuir al progrés abans esmentat, centrant-se en una tecnologia recent: el dispositiu de seguiment de moviment anomenat Leap Motion, no només mitjançant l'exploració de les seves capacitats d'interacció d'objectes virtuals, sinó empenyent els seus límits per permetre la interacció física amb objectes del món real. L'objectiu final d'aquest projecte, i la seva contribució a aquest camp, és la creació d'un dispositiu musical que utilitza la tecnologia de Leap Motion per a proporcionar un entorn on els usuaris poden interactuar amb els elements físics per jugar amb la música

Dynamic force spectroscopy of DNA hairpins. II. Irreversibility and dissipation

We investigate irreversibility and dissipation in single molecules that cooperatively fold/unfold in a two state manner under the action of mechanical force. We apply path thermodynamics to derive analytical expressions for the average dissipated work and the average hopping number in two state systems. It is shown how these quantities only depend on two parameters that characterize the folding/unfolding kinetics of the molecule: the fragility and the coexistence hopping rate. The latter has to be rescaled to take into account the appropriate experimental setup. Finally we carry out pulling experiments with optical tweezers in a specifically designed DNA hairpin that shows two-state cooperative folding. We then use these experimental results to validate our theoretical predictions.Comment: 28 pages, 12 figure

Energetics and performance of a microscopic heat engine based on exact calculations of work and heat distributions

We investigate a microscopic motor based on an externally controlled two-level system. One cycle of the motor operation consists of two strokes. Within each stroke, the two-level system is in contact with a given thermal bath and its energy levels are driven with a constant rate. The time evolution of the occupation probabilities of the two states are controlled by one rate equation and represent the system's response with respect to the external driving. We give the exact solution of the rate equation for the limit cycle and discuss the emerging thermodynamics: the work done on the environment, the heat exchanged with the baths, the entropy production, the motor's efficiency, and the power output. Furthermore we introduce an augmented stochastic process which reflects, at a given time, both the occupation probabilities for the two states and the time spent in the individual states during the previous evolution. The exact calculation of the evolution operator for the augmented process allows us to discuss in detail the probability density for the performed work during the limit cycle. In the strongly irreversible regime, the density exhibits important qualitative differences with respect to the more common Gaussian shape in the regime of weak irreversibility.Comment: 21 pages, 7 figure

Constant rate thermal analysis of a dehydrogenation reaction

The Constant Rate Thermal Analysis (CRTA) procedure has been employed for the first time to study the kinetics of MgH2 dehydrogenation by thermogravimetry under high vacuum. CRTA implies controlling the temperature in such a way that the decomposition rate is maintained constant all over the process, employing the mass change as the experimental signal proportional to the reaction rate. The CRTA curves present a higher resolution power to discriminate the kinetic model obeyed by the reaction in comparison with conventional heating rate curves. The combined kinetic analysis has been applied to obtain the kinetic parameters, which show that MgH2 decomposition under high vacuum obeys first-order kinetics (F1). It has been proposed that the dehydrogenation of MgH2 under high vacuum takes place by instantaneous nucleation in the border line of the bidimensional crystallites followed by the growth of the nuclei.España Mineco FEDER CTQ2014-52763-C2-1-RJunta de Andalucía FEDER TEP-190

The Problem of Time from the Perspective of the Social Sciences

This article presents a critical review of ideas about time in modern societies & especially in the social sciences. Man in modern society perceives, reflects, & registers time in a series of contexts, whether this involves questions of thought, the physical body, nature, or society. Current studies that address the question of time in many cases do so through a comparison of archaic temporal awareness & modern temporal awareness, & attempt to describe when & how this historical shift came about. According to O. Rammstedt four distinct historical types of understanding time can be distinguished: (1) occasional awareness of time based on a distinction made between 'now' & 'not-now'; (2) cyclical awareness of time; (3) linear awareness of time with a closed future, & (4) linear awareness of time with an open future. In contemporary social sciences four main theoretical perspectives can be observed. The first one assumes that the basic principles of order are or should be considered as unchanging. These principles express themselves as invariants. In the 20th century we can find them in structural linguistics, & in social sciences with a structuralist orientation. The second approach resembles the previous one in that it also considers the existence of unchanging principles of order. However, it differs through the assumption that these principles reveal themselves in time. The third approach can be considered de facto a sort of special degree of the second, ie, closed historical concept. Unlike the teleological character of the latter, however, it considers human intervention as a necessary condition for the achievement of a future aim. The fourth concept is founded on the idea that the basic principles of order can be revealed only in time. Unlike the second, however, it does not consider the main organizing principles to be unchanging, but rather concludes that in each contemporary period they are open to change. This fourth approach, which can be described as 'temporalized sociology' & which is expressed in works of such authors as G. H. Mead, A. Schutz, N. Elias, N. Luhmann, or A. Giddens, stresses a relatively open future, emergence, novelty, & the concept of discontinuity. In the opinion of the author of this study another concept should be added to our understanding of time: ie, 'irreversibility.' It is a feature of those systems that are far from being balanced & in which, in order to be able to predict future states, it is not enough to know the laws & the initial conditions