THE METHOD OF SIMULATED MAXIMUM LIKELIHOOD FOR THE ESTIMATON OF DYNAMIC ORDERED PROBIT: AN APPLICATION TO COUNTRY-RISK FOR NON-DEVELOPED COUNTRIES

This paper aims to give a detailed explanation of the econometric methodology necessary to estimate dynamic probit models with ordinal dependent variables. A typology of cases are established which appear when considering different choices of individual heterogeneity along with time correlation. To be able to estimate by maximum likelihood the models which come out of the different alternatives proposed, simulation techniques are used and put into practice by the GHK simulator and, in this way, estimators by simulated maximum likelihood are obtained. Finally, all the models described are used to measure and determine the macroeconomic factors which explain the ratings of country-risk in non-developed countries.Country risk, panel data, external debt, dynamic ordered probit

Aerial navigation in obstructed environments with embedded nonlinear model predictive control

We propose a methodology for autonomous aerial navigation and obstacle avoidance of micro aerial vehicles (MAV) using nonlinear model predictive control (NMPC) and we demonstrate its effectiveness with laboratory experiments. The proposed methodology can accommodate obstacles of arbitrary, potentially non-convex, geometry. The NMPC problem is solved using PANOC: a fast numerical optimization method which is completely matrix-free, is not sensitive to ill conditioning, involves only simple algebraic operations and is suitable for embedded NMPC. A C89 implementation of PANOC solves the NMPC problem at a rate of 20Hz on board a lab-scale MAV. The MAV performs smooth maneuvers moving around an obstacle. For increased autonomy, we propose a simple method to compensate for the reduction of thrust over time, which comes from the depletion of the MAV's battery, by estimating the thrust constant

A comparative study of multiple-criteria decision-making methods under stochastic inputs

This paper presents an application and extension of multiple-criteria decision-making (MCDM) methods to account for stochastic input variables. More in particular, a comparative study is carried out among well-known and widely-applied methods in MCDM, when applied to the reference problem of the selection of wind turbine support structures for a given deployment location. Along with data from industrial experts, six deterministic MCDM methods are studied, so as to determine the best alternative among the available options, assessed against selected criteria with a view toward assigning confidence levels to each option. Following an overview of the literature around MCDM problems, the best practice implementation of each method is presented aiming to assist stakeholders and decision-makers to support decisions in real-world applications, where many and often conflicting criteria are present within uncertain environments. The outcomes of this research highlight that more sophisticated methods, such as technique for the order of preference by similarity to the ideal solution (TOPSIS) and Preference Ranking Organization method for enrichment evaluation (PROMETHEE), better predict the optimum design alternative

Thymine starvation causes abortive initiation of chromosome replication critical for cell death in Escherichia coli

Presentado en: XXXVI Congreso SEBBM (Sociedad Española de Bioquímica y Biología Molecular), Madrid, 4-6 septiembre, 2013Thymineless death (TLD), a phenomenon in which thymine auxotrophy becomes lethal when cells are starved for thymine, can be prevented by rifampicin addition. In this work, we have obtained evidence indicating that among the effects of RNA polymerase inhibition by rifampicin, the inhibition of chromosomal replication initiation is the process responsible for TLD suppression. We show that diminishing, abolishing or increasing the transcription level around oriC alleviates TLD by limiting the chromosomal initiation capacity (ChIC) generated under thymine starvation. TLD suppression was eliminated by DnaA inactivation or the deletion in the left half of the replication origin or deletion of the DnaA-boxes located in the right half of the oriC region. In accordance with these data, two-dimensional DNA electrophoresis gels showed an accumulation of simple-Y and bubble arc replication intermediates, as well as recombination structures at the oriC region during thymine starvation. None of these structures were observed under genetic or physiological conditions that suppress TLD. These results demonstrate that abortive initiations of chromosome replication occur under thymine starvation, supporting the idea that these events are a critical target for the lethal damage caused by thymine starvation and that results in TLD.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Tunable Holographic Components in WDM Optical Networks

This paper describes the applications of a multipurpose holographic device in optical networks with Coarse and Dense Wavelength Division Multiplexing (CWDM/ DWDM) technologies. In its basic structure, it can operate as a tunable wavelength filter, wavelength multiplexer or λ router. By using a more complex structure, the device works as OADM (Optical Add Drop Multiplexer) or OS (Optical Switch). Some simulations of the basic devices, from the optical transmission point of view, are made to match the transmission parameters for the application in optical networks. Performance parameters of the device, like switching time, losses, cross-talk or polarization insensitivity are analyzed and compared with other multiplexing or switching technologies. To complete the review of these components, a study of computer generated holograms (CGH) design is carried out. The results are used in the design of holographic devices to perform different applications: in Metro networks, where a design of a holographic device with wavelength conversion and routing is analyzed, or, in Access Networks like a tunable filter or demultiplexer in Fiber to the Home/Business (FTTH/FTTB) topologies

Viabilidad de un PLL (Phase-Locked Loop) para la extracción de componentes sinusoidales en series de datos financieros

Las series de datos financieros (SP500, Dow Jones, Nasdaq, etc) se pueden analizar aplicando técnicas de procesado digital de señales con objeto de extraer cierta información. En los últimos años ha aparecido una nueva técnica que permite descomponer una señal en sus cíclicas, la transformada de Hilbert-Huang. Cuando se aplica esta transformada a una serie de datos financieros aparecen separadas varias componentes sinusoidales y una componente tendencial. Tomando como referencia cualquiera de las componentes sinusoidales y aplicando simples señales de trading sobre la misma es factible obtener rentabilidades positivas de forma continuada. Sin embargo, estas señales están generadas a posteriori. Con objeto de obtener estas señales en tiempo real (online) se propone la utilización de un PLL (Phase- Locked Loop) para tener una referencia enganchada en fase en cualquiera de las componentes sinusoidales, obtenidas previamente con la transformada de Hilbert- Huang, y a partir de ella realizar una estrategia de inversión