Exact Stochastic Unraveling of an Optical Coherence Dynamics by Cumulant Expansion

A numerically exact Monte Carlo scheme for calculation of open quantum system dynamics is proposed and implemented. The method consists of a Monte-Carlo summation of a perturbation expansion in terms of trajectories in Liouville phase-space with respect to the coupling between the excited states of the molecule. The trajectories are weighted by a complex decoherence factor based on the second-order cumulant expansion of the environmental evolution. The method can be used with an arbitrary environment characterized by a general correlation function and arbitrary coupling strength. It is formally exact for harmonic environments, and it can be used with arbitrary temperature. Time evolution of an optically excited Frenkel exciton dimer representing a molecular exciton interacting with a charge transfer state is calculated by the proposed method. We calculate the evolution of the optical coherence elements of the density matrix and linear absorption spectrum, and compare them with the predictions of standard simulation methods.Comment: 11 pages, 6 figure

A system to determine the inertia tensor of small satellites

Context: Attitude control of a satellite relies upon a precise determination of its inertia tensor. However, the determination of the inertia tensor of a complex system, as is the case of satellites, completely escapes analytic methods. Even though the inertia tensor can be obtained by means of CAD models, this method is subject to a degree of uncertainties due to required approximations in the materials definition and the geometry of some components. Furthermore, cabling is often difficult to integrate into CAD designs, which may introduce an additional source of error. Aims: In this Degree Thesis, we propose the design of a torsion pendulum which will allow us to determine all the components of the inertia tensor of a CubeSat-type object. We intend to achieve more efficiency and better accuracy than performing standard CAD simulations. Methodology: Our starting point is a general idea of a pendulum, Our sketch involves a set of fixed parts, mostly with structural purposes, and a set of mobile parts. The latter must be able to rotate about the axis of a torsion fiber. Besides, it must connect to a platform on top of which the CubeSat whose tensor of inertia we intend to determine will be placed. By measuring the period of rotation of the mobile parts (which include the platform and CubeSat), it is easy to derive the inertia moment of rotating set about the axis given by the torsion fiber. The detailed design of the pendulum was executed with the software SolidWorks. Foundations of Classical Mechanics and rotation matrix Algebra, as well as the software MatLab were required to develop the operation analysis of the proposed pendulum. Results: We designed, obtained detailed maps, and developed stress analysis calculations of the pendulum. Besides, we completed the mathematical analysis which allows to build the inertia tensor of a CubeSat, by using individual inertia moments, derived from a set of period measurements obtained with different orientations of the CubeSat. Finally, we used basic error analysis to show that the components of the inertia tensor can be obtained with the desire precision by using feasible period measurements.Contexto: El control de actitud de un satelite se basa en una determinaci ´ on precisa de ´ su tensor de inercia, sin embargo, la determinacion del tensor de inercia de un sistema ´ complejo, como es el caso de los satelites, escapa por completo a los m ´ etodos anal ´ ´ıticos. Aunque el tensor de inercia se puede obtener por medio de modelos CAD, este metodo ´ esta sujeto a un grado de incertidumbre debido a las aproximaciones requeridas en la ´ definicion de materiales y en la geometr ´ ´ıa de algunos de los dispositivos. Ademas, el ´ cableado a menudo es dif´ıcil de integrar en los disenos ˜ CAD, e introduce una fuente de error adicional. Objetivos: En este trabajo de final de grado, proponemos realizar el diseno y el an ˜ alisis ´ de las bases del funcionamiento de un pendulo de torsi ´ on que permite determinar todos ´ los componentes del tensor de inercia de un objeto tipo CubeSat, con mayor eficiencia y precision que la que nos permitir ´ ´ıa un analisis de ´ CAD. Metodolog´ıa: Partimos de una idea general de un pendulo, que incluye un conjunto de par- ´ tes fijas con funcion principalmente estructural, y de partes que pueden rotar alrededor de ´ una fibra de torsion, unida a una plataforma sobre la cual se puede situar el ´ CubeSat cuyo tensor de inercia deseamos conocer. A partir de las medidas del periodo de rotacion de ´ la plataforma podemos determinar de manera sencilla el momento de inercia del conjunto de partes giratorias alrededor del eje de la fibra de torsion. Para realizar el dise ´ no deta- ˜ llado del dispositivo utilizamos el software SOLIDWORKS. Para analizar las bases de su funcionamiento utilizamos conocimientos de Mecanica Cl ´ asica y ´ Algebra de matrices de ´ rotacion, as ´ ´ı como el software MATLAB. Resultados: Hemos disenado, presentado los planos, y realizado un an ˜ alisis num ´ erico de ´ estres sobre el p ´ endulo propuesto. Adem ´ as hemos completado el desarrollo matem ´ atico ´ que permite construir el tensor de inercia del CubeSat, a partir de valores individuales de momentos de inercia, derivados de las medidas del periodo de rotacion del sistema ´ con distintas orientaciones del CubeSat. Finalmente, nuestro calculo de errores b ´ asico ´ muestra que podemos obtener valores de las componentes del tensor de inercia con la precision deseada, a partir de medidas de periodos factibles

Breaking down the EU emissions trading system through the literature

Treball Final de Grau en Economia. Codi: EC1049. Curs acadèmic: 2021/2022I began to research with the sole purpose of trying to understand the carbon market,out of curiosity, right after my summer internship at Esmalglass-Itaca group, a heavy energy dependent producer in the tile, frits and glazes industry, and a heavy carbon emitter. The environmental quality control team showed me some data proving that the group (Altadia) has reduced its emissions by 40% since 2005, and yet in the carbon market they have gone from a selling position in regard to emission rights, to a buyers one in the market perspective. They have to buy emission rights despite such a significant reduction. Since then, all I wanted to do was to understand how the market works and what the experts have to say about its trends, market mechanisms and controversies

Building hypermedia artifacts by the systematic use of the flexible process model

Most of the current hypermedia model life cycles focus in analysis and design issues, ignoring crucial tasks and activities of hypermedia projects. Others do not take care of basic Software Engineering concepts such as planning, physical and logical modeling, validation and quality assurance, among other issues. In this paper we propose an integrated software process model, called Flexible Process Model, useful in building hypermedia artifacts. This strategy, when instanciated in a specific project, implies a systematic use of model-based constructors, both logical and physical models. The main benefits of this process model are: a) it covers all the principal phases and tasks of a hypermedia project; b) this clear break down can contribute fairly to project planning and can help to establish milestones and metrics; c) it fosters a positive balance by a systematic use of logical and physical modeling; d) it facilitates human communication; e) it promote process improvement and standardization. Therefore, we will discuss and represent, in a medium level of granularity, the phases, tasks and activities, mainly in the dynamic modeling phase. Also we will present some perspectives, stressing the functional, methodological and behavioral perspectives of the three-phased Flexible Process Model. Finally, we will discuss related works and concluding remarks.Eje: Ingeniería de software. Bases de datosRed de Universidades con Carreras en Informática (RedUNCI

Heart Failure Factors: a database approach

This project proposes to use data to find correlations with the amount of heart failures. The student will have to collect data. This information will be used to extract correlations with a contrastive database that contains details on heart attacks using the temporal information as main anchor.This project aims to find relationships between psychological stress factors and heart attacks that took place in Catalunya between 2010 and 2016. We have measured these factors through the news that were published in La Vanguardia?s Twitter account, processed by Machine Learning techniques, such as Word Embeddings or Clustering.El objetivo de este proyecto es encontrar las relaciones entre factores de estrés psicosocial y ataques al corazón que se produjeron en Cataluña entre 2010 y 2016. Estos factores se miden a través de las noticias publicadas en la cuenta de Twitter de La Vanguardia, procesadas con técnicas de Machine Learning, tales como Word Embeddings y Clustering.L'objectiu d'aquest projecte és trobar les relacions entre factors d'estrès psicosocial i els atacs de cor que es van produir a Catalunya entre 2010 i 2016. Aquests factors es mesuren a través de les notícies publicades al compte de Twitter de La Vanguardia, processades amb tècnques de Machine Learning, com Word Embeddings i Clustering

Overview of a framework to hypermedia process modeling

In this work, we discuss aspects of a framework to support the understanding and the improvement in hypermedia development processes. The framework is built taking into account two modeling approaches and four domain levels. The modeling approaches are called prescriptive and descriptive respectively, and the domain layers are called, namely, enactment, customization, representation, and reuse/knowledge domains. We feed a potential project regarding this framework by applying a mixture of expression and analysis-oriented descriptive process modeling strategy, and expression, analysis and guided-oriented prescriptive process modeling strategy. That is, the actual or desired entities (process, artifact, and resource) are just described, represented, and analyzed in a somewhat formal way. This potentially allows us to understand, communicate, guide and improve different aspects in hypermedia development projects. Ultimately, we summarize some techniques and mechanisms for prescriptive and descriptive software modeling customized to the hypermedia domain. In addition, we present in-progress researchs and developments.Ingeniería de SoftwareRed de Universidades con Carreras en Informática (RedUNCI

Optimal Decision-Making under Uncertainty - Application to Power Transmission Investments

Economists define investment as the act of incurring immediate costs with the expectation of future returns. An investment project, as every asset has a value. For successfully investing in and managing these assets is crucial not only recognizing what the value is but also the sources of this value. Most investment decisions share three characteristics in different degrees. First, investments are partially or totally irreversible. Roughly speaking, the initial investment cost is at least partially sunk; i.e. it is impossible to recover all the expenditures if the decision-maker changes his mind. Second, there is uncertainty in the revenues from the investment, and therefore, risk associated with this. Third, all decision-making has some leeway about the timing of the investment. It is possible to defer the decision making to get more information about the future. These three features interact to determine the optimal decisions of investors on a given investment project. Transmission utilities are faced with investment projects, which hold these three characteristics: irreversibility, uncertainty and the choice of timing. In this context, an efficient decision making process is, therefore, based on managing the uncertainties and understanding the relationships between risks and opportunities in order to achieve a well-timed investment execution. Therefore, strategic flexibility for seizing opportunities and cutting losses contingent upon the market evolution is of huge value. Strategic flexibility is a risk management method that is gaining ongoing research attention as it enables properly managing major uncertainties, which are unsolved at the time of making decisions. Hence, valuing added flexibility in transmission investment portfolios, for instance, by investing in power electronic-based controller meanwhile transmission line projects are deferred, is necessary to make optimal network upgrading. Nevertheless, expressing the value of flexibility in economic terms is not a trivial task and requires new, sophisticated valuing tools, since the traditional investment theory has not recognized the important implications of the interaction between the three aforementioned investment features. Any attempt to quantify investment flexibility almost naturally leads to the concept of Real Options (RO). The RO technique provides a well-founded framework –based on the theory of financial options, and consequently, stochastic dynamic programming- to assess strategic investments under uncertainty. In the first RO applications, valuation was normally confined to the investment options that can be easily assimilated to financial options, for which solutions are well-known and readily available. Nevertheless, an investor confront with a diverse set of opportunities. From this point of view, investment projects can be seen as a portfolio of options, where its value is driven by several stochastic variables. The introduction of multiple interacting options into real options models highly increases the problem complexity, making traditional numerical approaches impracticable. However in the recent years, simulation procedures for solving multiple American options have been successfully proposed. One of the most promising approaches is the Least Square Monte Carlo (LSM) method proposed by Longstaff and Schwartz in 2001. LSM method is based on stochastic chronological simulation and uses least squares linear regression to determine the optimal stopping time (optimal path) in the decision making process. This chapter lays out a general background about key concepts -uncertainty and risk- and the most usual risk management techniques in transmission investment are provided. Then, the concept of strategic flexibility is introduced in order to set its ability for dealing with the uncertainties involved in the investment problem. In addition, new criteria and advantages of ROV approach compared with classical probabilistic choice are presented, by exposing a LSM-based method for decomposing and evaluating the complex real option problem involved in flexible transmission investments under uncertainties. The proposed methodology is applied in a study case which evaluates an interconnection reinforcement on the European interconnected power system, by showing how the valuation of flexibility is a key task for making efficient and well-timed investments in the transmission network. The impact of two network upgrades on the system-wide welfare is analyzed. These upgrades are the development of a new interconnected line and the installation of a power electronic-based controller. Both upgrades represent measures to strengthen the German-Dutch interconnections due to the fact that these are among the most important corridors within the Central Western European (CWE) region. Hence, an interconnection project, which is currently under study, is compared to flexible investment in order to shed some light on the influence of the strategic flexibility on the optimal decision-making process. The research is focused on assessing the impact of different wind power in-feed scenarios in detail as well as the uncertainty of the demand growth, generation cost evolution and the installed wind capacity on the decision-making process. The presented approach might serve as a basis for a decision-making tool for regulatory agencies in order to quantify the necessity for network upgrades.Fil: Blanco, Gerardo. Universidad Nacional de Asunción; ParaguayFil: Olsina, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentin

Flexibility Value of Distributed Generation in Transmission Expansion Planning

The efficiency of the classic planning methods for solving realistic problems largely relies on an accurate prediction of the future. Nevertheless, the presence of strategic uncertainties in current electricity markets has made prediction and even forecasting essentially futile. The new paradigm of decision-making involves two major deviations from the conventional planning approach. On one hand, the acceptation the fact the future is almost unpredictable. On the other hand, the application of solid risk management techniques turns to be indispensable. In this chapter, a decision-making framework that properly handles strategic uncertainties is proposed and numerically illustrated for solving a realistic transmission expansion planning problem. The key concept proposed in this chapter lies in systematically incorporating flexible options such as large investments postponement and investing in Distributed Generation, in foresight of possible undesired events that strategic uncertainties might unfold. Until now, the consideration of such flexible options has remained largely unexplored. The understanding of the readers is enhanced by means of applying the proposed framework in a numerical mining firm expansion capacity planning problem. The obtained results show that the proposed framework is able to find solutions with noticeably lower involved risks than those resulting from traditional expansion plans.Fil: Vásquez, Paúl. Consejo Nacional de Electricidad; EcuadorFil: Olsina, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Energía Eléctrica. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentin