Voltage noise analysis with ring oscillator clocks

Voltage noise is the main source of dynamic variability in integrated circuits and a major concern for the design of Power Delivery Networks (PDNs). Ring Oscillators Clocks (ROCs) have been proposed as an alternative to mitigate the negative effects of voltage noise as technology scales down and power density increases. However, their effectiveness highly depends on the design parameters of the PDN, power consumption patterns of the system and spatial locality of the ROCs within the clock domains. This paper analyzes the impact of the PDN parameters and ROC location on the robustness to voltage noise. The capability of reacting instantaneously to unpredictable voltage droops makes ROCs an attractive solution, which allows to reduce the amount of decoupling capacitance without downgrading performance. Tolerance to voltage noise and related benefits can be increased by using multiple ROCs and reducing the size of the clock domains. The analysis shows that up to 83% of the margins for voltage noise and up to 27% of the leakage power can be reduced by using local ROCs.Peer ReviewedPostprint (author's final draft

Sensitivity equations and calibration requirements on airborne interferometry

The usage of an airborne interferometric SAR to mass map production is strongly dependent on the capability of performing the data processing in a near automatic mode. One of the main limitations is related to both the accurate calibration of the system parameters, its stability from flight to flight and the correct in-flight recording of aircraft position and attitude. The unstable movements of an airborne SAR platform, if recorded in an accurate manner, can be corrected during the processing step. Measurement errors and time drifts lead to location errors in the final DEM. The system requirements in both accuracy and stability to fulfil a quality-mapping requirement can be resolved from the sensitivity equations. The same equations can be also used to calibrate the system parameters from the location errors on the imaging of well-known targets, usually corner reflectors.Peer ReviewedPostprint (published version

Mineralogical composition and biomass studies of the microbial mats sediments from the Ebro Delta, Spain

The mineral composition of the microbial mats at La Banya spit was studied. The spit is formed by a narrow sand bar and a peninsula and is located south of the main body of the Ebro Delta (Tarragona, Spain). Although quartz was the predominant mineral component in all sampling sites, clay, feldspars, calcite, aragonite, halite, dolomite and gypsum were also found. An increase in both the fine material (clay) and the halite content was observed in the sites influenced by nearby salterns. The amount of each mineral did not differ significantly along a 55 cm deep profile, except for halite and aragonite, which reached a maximum in the surface and decreased with depth. Dolomite, which ranged from 0.5 to 5% (w/w), is a possible indicator of sulfate-reducing bacteria activity in the past. Organic carbon and total nitrogen were quantified for biomass assessment. Total nitrogen ranged from 0.1 to 0.56% in the uppermost layer, where the microbial mat is active, but was undetectable at deeper layers. Organic carbon ranged from 1 to 5.5% in the active microbial mat layers and decreased to 0.3% at deeper layers. During the summer, both organic carbon and total nitrogen contents (biomass) of the microbial mat samples from some sites increase, whereas other sites show constant concentrations throughout the year, and others have a fluctuant biomass content

Programación lógica

Treballs Finals de Grau d'Enginyeria Informàtica, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2015, Director: Juan Carols Martínez AlonsoThis text aims to collect the research work done in a very specific field of programming, logic programming. Therefore, I have focused my work on the study of first-order logic and specific language for this paradigm: Prolog. Dr. Peña Marí wrote in bis book "De Euclides a Java", about the history of algorithmics: «This story begins almost at very same time that the history of mankind... ». But this study does not go that far. Since the purpose of the work is programming -or rather, a part of it-, we must move forward in time a bit... The aim of this work is to expand the knowledge received in the course of "Logica i llenguatges, Grade Computer Engineering" at UB. In previous editions more study material was dealt with, so that the course had to be divided in two different matters. My work has consisted on studying all materials that are no longer a topic within the course, extending them when necessary, namely the study of Prolog language. I want to start my presentation by putting, both in historical and scientific context, everything connected with what I'm going to talk about in this work. In this introductory chapter I will try to provide you with some historical details. I will cite the most basic, necessary elements that make possible programming, the programmable machines. I will give a context to our programming paradigm, that is, logic programming. In chapter 2 I will explain the first-order logic, in full detail. I will review the basic and most characteristic predicate language concepts, interpretations in these languages and some logical equivalences. At the end we'll see the unification algorithm and the method of resolution specifics for languages with declarative paradigm, and more specifically, the logical one. In chapter 3 we will see the programming language Prolog. We will see its relationship with the declarative and logic languages, its evolution throughout history, the way we use it, its basic elements, and how it makes it possible to unify terms. We'll see the way lists are dealt with, arithmetic expressions are used, cut is used, etc. We will finish in chapter 4 with a few solved exercises to exemplify all the the information in this work, either related to predicate logic, or to fundamentals of Prolog

Fractals: objects to better explain our world

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2017, Núria Fagella Rabionet[en] In this paper we will look at some properties fractals and show the usefulness of one of them, the fractal dimension, for the study of natural and artificial phenomena. We will center our attention on fractals generated by Iterated Function Sets (IFS), which we will define as a system of contractive mappings on non-empty compact sets in a complete metric space. First, we will present some simple, well known, fractals, and show how to generate them with a geometrical construction. To compute these objects, we will use two distinct algorithms based on the iteration of IFS, a deterministic and a random one. We will then see an application of the fixed point theorem for IFS, named the Collage Theorem. We will show that an IFS’s attractor is unique and independent of the initial set. Moreover, we will show that both the deterministic and the random algorithms converge to the same limit: the attractor of the system. Having studied fractals generated by IFS, we will go on to look at fractal dimensions. For this purpose we will review the classic concept of dimensions, and broaden it to include non-integer dimension. We will see different types of fractal dimensions, some of which are suited to a specific type of fractals, such as the self-similarity dimension applicable to self-similar shapes, and a more general dimension, applicable to any fractal, namely, the Hausdorff-Besicovitch Dimension. We will also see the Box-counting algorithm, which approximates the Hausdorff-Besicovitch Dimension and is often used in its stead because of the complexity of calculating the dimension. We will conclude our exploration of fractal dimensions with the presentation of a small personal contribution to this area – our own version of a program which implements the box-counting algorithm on images. In the last chapter we will see some examples of the practical uses of the fractal dimension in fields of study as diverse as medicine, market research, image classification and so on. Through these examples we can appreciate the impact of fractals on our way of modeling or explaining our world

Using SVD Analysis of Combined Altimetry and Ocean Color Satellite Data for Assessing Basin Scale Physical-Biological Coupling in the Mediterranean Sea

Capítulo publicado en: Fatoyinbo, Temilola (ed.). Remote Sensing of Biomass - Principles and Applications. [S.l.]: InTech, 2012Peer Reviewe

Estimation of wind forcing and analysis of near-inertial motions generated by a storm in a submarine canyon with an ensemble Kalman filter

© 2014 Elsevier Ltd. The impact of high-frequency winds on the generation and propagation of inertial currents in the Palamós submarine canyon (northwestern Mediterranean) during a severe storm on 9-16 November 2001 is evaluated in an ocean circulation model. Moored current meter time series collected in and around the canyon during the storm are assimilated with an ensemble adjustment Kalman filter (EAKF) to adjust wind forcing through a simultaneous state and parameter estimation approach. Winds are included as time-dependent parameters, which are updated in each assimilation step as part of the model state. A simulation forced by the estimated wind significantly improves simulation with winds from the atmospheric reanalysis (the RMS error reduction is about 50%). This is due to the higher energy for the estimated wind at inertial period in the clockwise rotating component, which enhances generation of near-inertial motions. The surface inertial energy however does not decay as rapidly compared to a simulation with data assimilation. It is suggested that the submesoscales, which are present in the data assimilated simulation, are effective in channeling a spatially heterogeneous vertical propagation of near-inertial motions.This research utilized resources at the New York Center for Computational Sciences at Stony Brook University/Brookhaven National Laboratory which was supported by the U.S. Department of Energy under Contract no. DE-AC02-98CH10886 and by the State of New York. This work was partially carried out in the framework of the CANYONS project, funded by the “Dirección General de Enseñanza Superior e Investigación Científica” (MAR1999-1060). The authors gratefully thank all the personnel involved in the CANYONS project and surveys. A. Jordi's work was supported by a Ramón y Cajal grant (RYC-2010-06898) from the Spanish Ministry of Economy and CompetitivenessPeer Reviewe

SbPOM: A parallel implementation of Princenton Ocean Model

This paper presents the Stony Brook Parallel Ocean Model (sbPOM) for execution on workstations, Linux clusters and massively parallel supercomputers. The sbPOM is derived from the Princenton Ocean Model (POM), a widely used community ocean circulation model. Two-dimensional data decomposition of the horizontal domain is used with a halo of ghost cells to minimize communication between processors. Communication consists of the exchange of information between neighbor processors based on the Message Passing Interface (MPI) standard interface. The Parallel-NetCDF library is also implemented to achieve a high efficient input and output (I/O). Parallel performance is tested on an IBM Blue Gene/L massively parallel supercomputer, and efficiency using up to 2048 processors remains very good. © 2012 Elsevier Ltd.his research utilized resources at the New York Center for Computational Sciences at Stony Brook University/Brookhaven National Laboratory which was supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 and by the State of New York. A. Jordi's work was supported by a Ramón y Cajal grant from MICINNPeer Reviewe

Realización de un tutorial de SEAFEM para analizar el comportamiento de estructuras en el mar

Este tutorial está compuesto por unos ejemplos explicativos que permiten interactuar, de forma sencilla, con el programa SeaFEM. Este programa permite, mediante el uso del Método de los Elementos Finitos, modelar la mar, tanto su oleaje como sus corrientes así como los elementos que por alguna necesidad se introducen en ella para realizar una función (barcos, plataformas, boyas, elementos para captación de energía, diques, etc.). De este modo se puede conocer la interacción, es decir, las acciones que ejerce el mar sobre dichos elementos, en función del tipo de oleaje y corrientes y el elemento de estudio. Este hecho es muy importante en la fase de diseño de cualquiera de estos elementos dado que muestra las zonas críticas o susceptibles a fallo y las zonas no críticas, de modo que puede dar lugar a un óptimo diseño del elemento. En este trabajo concretamente se analizan 3 tipos de elementos que son un contenedor que cae a la mar, una boya y la pared de un espigón de un puerto y lo que se muestra es como se representan cada uno de estos elementos, así como la discretización del mar, como se introducen las condiciones de contorno en cada situación y todos los pasos necesarios para que el programa realice el cálculo. Finalmente se enseña cómo se analizan los resultados obtenidos en cada uno de los casos

La renovació urbana a l'Hospitalet

La ciutat de l'Hospitalet de Llobregat ha engegat un important projecte de renovació urbana emmarcat dins la figura del Pla l'Hospitalet 2010 (Pla L'H 2010), sorgit a partir d'una profunda reflexió sobre les condicions urbanístiques, econòmiques i socials de la ciutat i el seu context territorial. El Pla no es planteja ni com un document formal de planificació estratègica ni com a figura de planejament urbanístic en el sentit normatiu, sinó com un recull de mètodes, concepcions i directrius de treball per a l'obtenció dels canvis desitjats per a la ciutat, que ja compta amb instruments propis de desenvolupament: l'Agència de Desenvolupament Urbà (ADU) i L'H 2010 Societat Privada Municipal, S.A., cadascun dels quals compleix funcions específiques dins l'estratègia global de canvi, de manera que, mentre l'ADU ha de gestionar i elaborar els instruments urbanístics adequats per a la consecució dels objectius prioritaris, L'H 2010 S.A. ha de dur a terme les actuacions urbanístiques necessàries (redacció de projectes, adquisició de terrenys i immobles, execució d'obres, etc.) per a l'assoliment d'aquests mateixos objectius.La ciudad de l'Hospitalet de Llobregat ha iniciado un importante proyecto de renovación urbana enmarcado en la figura del Pla l'Hospitalet 2010 (Pla L'H 2010), surgido a partir de una profunda reflexión sobre las condiciones urbanísticas, económicas y sociales de la ciudad y su contexto territorial. El plan no se plantea ni como un documento formal de planificación estratégica ni como una figura de planeamiento urbanístico en el sentido normativo, sino como un conjunto de métodos, conceptos y directrices de trabajo para la obtención de los cambios deseados para la ciudad, que cuenta ya con instrumentos propios de desarrollo: la Agència de Desenvolupament Urbà (ADU) i L'H 2010 Societat Privada Municipal, S.A., cada uno de los cuales cumple funciones específicas dentro de la estrategia global de cambio, de forma que, mientras la ADU debe elaborar y gestionar los instrumentos urbanísticos adecuados para la consecución de los objetivos prioritarios, L'H 2010 S.A debe llevar a cabo las actuaciones urbanísticas necesarias (redacción de proyectos, adquisición de terrenos e inmuebles, ejecución de obras,etc.) para alcanzar esos mismos objetivos.L'Hospitalet de Llobregat has started an important urban renovation project, framed in the figure of the Pla l'Hospitalet 2010 (Pla L'H 2010), that comes from a profound reflection about its urban, economic and social conditions and its territorial context. The Plan is not intended to be neither a formal document nor a town planning figure in a normative sense, but an outline of methods, concepts and guidelines to achieve the aimed changes for the city, that already counts on its own development tools: the Agència de Desenvolupament Urbà (ADU) and L'H 2010 Societat Privada Municipal, S.A, every of which fulfill specific functions in the global change strategy, in a manner that, while ADU should manage and elaborate the most appropriate planning instruments to achieve the priority objectives, L'H 2010 S.A. should carry out the the needed urban actions (acquisition of plots and buildings, execution of works, etc.) to achieve these same objectives.La ville de l'Hospitalet de Llobregat a mis en marche un important projet de rénovation urbaine dans le cadre du Pla l'Hospitalet 2010 (Pla l'H 2010) surgit d'une profonde réflexion sur les conditions urbanistiques, économiques et sociales de la ville et dans son contexte territorial. Le Plan (Plan de l'Hospitalet 2010) ne se présente ni comme un document explicite de planification stratègique, ni comme un modèle de l'aménagement urbanistique dans un terme normatif, mais comme un recueil des moyens, des conceptions et des directives de travail pour l'obtention des changements desirés pour la ville laquelle compte, déjà, avec des instruments propres de développement: l'Agencia de Desenvolupament Urbà (ADU. Agence de Développement urbain) et l'H 2010 Société Privée Municipale, SA., lesquelles ont des fonctions spécifiques dans la stratégie globale du changement, de façon que, tandis que l'ADU doit gestionner et élaborer les instruments urbanistiques appropiés pour la consécution des objectifs prioritaires, l'H 2010 SA, doit porter à termes les interventions urbanistiques nécessaires (rédaction du projet, adquisition des terrains et des immeubles, exécution des oeuvres, etc..) pour l'obtention de ces mêmes objectifs