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[ES] El desmantelamiento es la última fase en la vida de una Central Nuclear. Cuando un reactor nuclear cesa su actividad operativa, por razones de seguridad, económicas o tecnológicas, existen diferentes zonas contaminadas por sustancias radiactivas que pueden suponer un peligro para las personas o para el medio ambiente. El objetivo del desmantelamiento de una Central Nuclear es asegurar que los usos futuros que puedan darse al emplazamiento no supongan riesgos radiológicos inaceptables para las personas ni para el medio ambiente. Para conseguir este objetivo, el desmantelamiento de las zonas contaminadas de una central debe estudiarse y diseñarse de forma correcta, atendiendo a criterios de Protección Radiactiva en todas las actividades. La finalidad del presente trabajo es estudiar y diseñar el proceso de desmantelamiento de la piscina de combustible de un reactor de agua ligera. Para ello, se ha utilizado la simulación del transporte de partículas mediante el método de Monte Carlo, desarrollando un modelo de cálculo de la piscina de combustible con el programa MCNP5. La dosis calculada mediante este modelo y la caracterización de la contaminación radiactiva existente en la piscina de combustible han servido como base para diseñar el proceso de desmantelamiento y gestionar las actividades relativas al mismo de forma segura para el personal. En el proceso de descontaminación radiactiva de cualquier zona contaminada, se producen residuos radiactivos que, de no ser gestionados correctamente, pueden producir daños. En el presente trabajo también se ha desarrollado un plan de gestión de residuos radiactivos donde se estudian diversos métodos para evitar que dichos residuos produzcan efectos nocivos a las personas o al medio ambiente., [EN] Dismantling is the last phase in the life of a Nuclear Power Plant. When a nuclear reactor ceases its operational activity, for safety, economic or technological reasons, there are different areas contaminated by radioactive substances that can cause a danger to people or the environment. The objective of the decommissioning of a Nuclear Power Plant is to ensure that future uses that may be given to the site do not create unacceptable radiological risks for people or the environment. To achieve this objective, the dismantling of the contaminated areas of a plant must be studied and designed correctly, taking into account Radiation Protection criteria in all activities. The purpose of this work is to study and design the dismantling process of the fuel pool of a light water reactor. For this, the simulation of the transport of particles by means of the Monte Carlo method has been used, developing a calculation model of the fuel pool with the MCNP5 code. The dose calculated using this model and the characterization of the radioactive contamination in the fuel pool have served as the basis for designing the decommissioning process and managing the related activities safely for the workforce. In the process of radioactive decontamination of any contaminated area, radioactive wastes are produced which, if not managed correctly, can cause damage. In this work, a radioactive waste management plan has also been developed where various methods are studied to prevent these wastes to produce harmful effects on people or the environment.

The harmonic closeness centrality measure associates, to each node of a graph, the average of the inverse of its distances from all the other nodes (by assuming that unreachable nodes are at infinite distance). This notion has been adapted to temporal graphs (that is, graphs in which edges can appear and disappear during time) and in this paper we address the question of finding the top-k nodes for this metric. Computing the temporal closeness for one node can be done in O(m) time, where m is the number of temporal edges. Therefore computing exactly the closeness for all nodes, in order to find the ones with top closeness, would require O(nm) time, where n is the number of nodes. This time complexity is intractable for large temporal graphs. Instead, we show how this measure can be efficiently approximated by using a &ldquo, backward&rdquo, temporal breadth-first search algorithm and a classical sampling technique. Our experimental results show that the approximation is excellent for nodes with high closeness, allowing us to detect them in practice in a fraction of the time needed for computing the exact closeness of all nodes. We validate our approach with an extensive set of experiments.

[ES] En las viviendas se encuentran diversos aparatos sanitarios para satisfacer las demandas de agua de sus usuarios, pero existe una incógnita interesante: ¿Cuántos aparatos sanitarios se utilizan a la vez en un grupo de viviendas? La respuesta está directamente relacionada con el caudal máximo que circulará a través de la tubería principal de la red de distribución de agua potable del grupo de viviendas. Se encuentran variedades de métodos para realizar los diseños de las redes interiores de distribución de agua potable y se desea conocer que tan fiables resultan para diferentes casuísticas. Esto motiva a desarrollar un modelo de predicción del caudal máximo demandado, que permita mediante simulación, asociar a cada caudal obtenido una cierta probabilidad de no excedencia, con el fin de determinar el comportamiento de los métodos más empleados en la práctica profesional, y compararlos entre sí mediante un parámetro común entre ellos. Esto permite elegir, de manera crítica, cual método escoger según cada caso de estudio por su fiabilidad. Se realizan simulaciones para cuatro tipos de viviendas, agrupando hasta 90 viviendas en una misma edificación, dando esto como resultado que el método racional español es el método que presenta valores de fiabilidad más constantes en los escenarios evaluados, y que el método UNE 149201 es el que ofrece mayor fiabilidad para pocas viviendas agrupadas (entre 20 y 30), brindando valores de probabilidad de no excedencia superiores a 95%. Puede apreciarse como la fiabilidad asociada a los diferentes métodos no depende únicamente de éstos, sino también del número y tipo de viviendas. Se discute también acerca del valor mínimo recomendado para el famoso coeficiente de simultaneidad de la norma francesa., [EN] In the houses there are several sanitary devices to meet the water demands of its users, but there is an interesting question: How many sanitary devices are used at the same time in a group of houses? The answer is directly related to the maximum flow that will circulate through the main pipe of the drinking water distribution network of the housing group. Varieties of methods are found to make the designs of the interior networks for the distribution of drinking water and it is desired to know how reliable they are for different cases. This motivates to develop a prediction model of the maximum flow demanded, which allows by simulation, to associate with each flow obtained a certain probability of non-exceedance, in order to determine the behavior of the methods most used in professional practice, and compare them between yes through a common parameter between them. This makes it possible to critically choose which method to choose according to each case study because of its reliability. Simulations are carried out for four types of dwellings, grouping up to 90 dwellings in the same building, giving this as a result that the Spanish rational method is the method that presents more constant reliability values ¿¿in the scenarios evaluated, and that the UNE 149201 method is the which offers greater reliability for few clustered houses (between 20 and 30), providing probability of non-exceedance values ¿¿greater than 95%. It can be seen how the reliability associated with the different methods depends not only on these, but also on the number and type of housing. The minimum recommended value for the famous simultaneity coefficient of the French standard is also discussed., [CA] En els habitatges es troben diversos aparells sanitaris per a satisfer les demandes d'aigua dels seus usuaris, però existeix una incògnita interessant: Quants aparells sanitaris s'utilitzen alhora en un grup d'habitatges? La resposta està directament relacionada amb el cabal màxim que circularà a través de la canonada principal de la xarxa de distribució d'aigua potable del grup d'habitatges. Es troben varietats de mètodes per a realitzar els dissenys de les xarxes interiors de distribució d'aigua potable i es desitja conèixer que tan fiables resulten per a diferents casuístiques. Això motiva a desenvolupar un model de predicció del cabal màxim demandat, que permeta mitjançant simulació, associar a cada cabal obtingut una certa probabilitat de no excedència, amb la finalitat de determinar el comportament dels mètodes més emprats en la pràctica professional, i comparar-los entre si mitjançant un paràmetre comú entre ells. Això permet triar, de manera crítica, com mètode triar segons cada cas d'estudi per la seua fiabilitat. Es realitzen simulacions per a quatre tipus d'habitatges, agrupant fins a 90 habitatges en una mateixa edificació, donant això com a resultat que el mètode racional espanyol és el mètode que presenta valors de fiabilitat més constants en els escenaris avaluats, i que el mètode UNEIX 149201 és el que ofereix major fiabilitat per a pocs habitatges agrupats (entre 20 i 30), brindant valors de probabilitat de no excedència superiors a 95%. Pot apreciar-se com la fiabilitat associada als diferents mètodes no depèn únicament d'aquests, sinó també del número i tipus d'habitatges. Es discuteix també sobre el valor mínim recomanat per al famós coeficient de simultaneïtat de la norma francesa.

Durante el desarrollo de un proyecto de inversión inmobiliario, suelen presentarse eventos inesperados que, de materializarse, pueden ocasionar efectos adversos o beneficiosos para el proyecto y para la compañía que lo emprende. Por lo tanto, se hace necesario una adecuada identificación y manejo de los riesgos, con el fin de disminuir los impactos negativos y tomar ventaja de los positivos, para tomar las decisiones acertadas y alcanzar los objetivos estratégicos. En este trabajo se presenta principalmente la influencia de los riesgos negativos, asociados a los imprevistos de proyectos inmobiliarios de estrato 4 de la ciudad de Medellín, en la etapa de pre inversión, a partir de la evaluación financiera, con el fin de estudiar cómo se podrían obtener los resultados de prefactibilidad con un método racional, a través de un análisis probabilístico, en contraste con el método tradicional que no toma en consideración los riesgos. Se utiliza la metodología PESTEL, la cual, a través de un estudio del entorno y del análisis de factores políticos, económicos, sociales, tecnológicos, ecológicos y legales, permite la identificación y el análisis cualitativo y cuantitativo de los riesgos. Este trabajo, a su vez, se apoya en el estudio de las 10 áreas del conocimiento definidas por el Project Management Institute (PMI), en su guía PMBOK para la identificación de los riesgos. Teniendo en cuenta lo anterior, se propone construir un modelo probabilístico a partir del flujo de caja de los proyectos inmobiliarios objeto de estudio, para su posterior simulación computacional a través del método Montecarlo, con la finalidad de obtener los indicadores de evaluación financiera y el factor AIU (Administración, Imprevistos y Utilidades) bajo condiciones de incertidumbre. El método permitirá obtener ecuaciones y gráficas de dichos indicadores para su comparación con el método tradicional., During the development of a real estate investment project, unexpected events usually happen, in such way that, if materialized, can cause adverse or beneficial effects for the project and for the company that undertakes it. Therefore, an adequate identification and management of the risks is necessary, in order to diminish the negative impacts and take advantage of the positive ones, to make the right decisions and reach the strategic objectives. This paper mainly presents the influence of negative risks, associated with the unforeseen events of stratum 4 real estate projects in the city of Medellín, in the preinvestment phase, based on the financial valuation, in order to study how to obtain the pre-feasibility results with a rational method through a probabilistic analysis, in contrast to the traditional method that does not take risks into consideration. PESTEL methodology is used, which, through a study of the environment and the analysis of political, economic, social, technological, ecological and legal factors, allows the identification and qualitative and quantitative analysis of risks. This work, in turn, is based on the study of the 10 knowledge areas defined by the Project Management Institute (PMI), in its PMBOK guide for the identification of risks. Considering the above, it is proposed to build a probabilistic model from the cash flow of the real estate projects under study, for subsequent computational simulation through the Monte Carlo method, in order to get the financial valuation indicators and the AIU (Administration, Incidentals and Utilities) factor under conditions of uncertainty. The method will allow obtaining equations and graphs of said indicators for comparison with the traditional method.

The current trend in genetic research is the study of omics data as a whole, either combining studies or omics techniques. This raises the need for new robust statistical methods that can integrate and order the relevant biological information. A good way to approach the problem is to order the features studied according to the different kinds of data so a key point is to associate good values to the features that permit us a good sorting of them. These values are usually the p-values corresponding to a hypothesis which has been tested for each feature studied. The Montecarlo method is certainly one of the most robust methods for hypothesis testing. However, a large number of simulations is needed to obtain a reliable p-value, so the method becomes computationally infeasible in many situations. We propose a new way to order genes according to their differential features by using a score defined from a beta distribution fitted to the generated p-values. Our approach has been tested using simulated data and colorectal cancer datasets from Infinium methylationEPIC array, Affymetrix gene expression array and Illumina RNA-seq platforms. The results show that this approach allows a proper ordering of genes using a number of simulations much lower than with the Montecarlo method. Furthermore, the score can be interpreted as an estimated p-value and compared with Montecarlo and other approaches like the p-value of the moderated t-tests. We have also identified a new expression pattern of eighteen genes common to all colorectal cancer microarrays, i.e., 21 datasets. Thus, the proposed method is effective for obtaining biological results using different datasets. Our score shows a slightly smaller type I error for small sizes than the Montecarlo p-value. The type II error of Montecarlo p-value is lower than the one obtained with the proposed score and with a moderated p-value, but these differences are highly reduced for larger sample sizes and higher false discovery rates. Similar performances from type I and II errors and the score enable a clear ordering of the features being evaluated.

If the horizontal rooftop of an existing building matches suitable structural criteria about its bearing capacity and the overall load transferred to foundation elements, green roofs represent an efficient solution for energy and operational performances improvement, with proven effects specifically in storm-water runoff phenomena control and heat island effect mitigation. In this paper, with reference of an existing building and its technological content, a model for the evaluation of the probability of economic affordability is described, considering a rooftop refurbishment intervention in different technological scenarios: three rooftop finishing layers – loose gravel, washed gravel tiles, waterproof membrane – are replaced, alternatively, by a thermal insulated cool roof or by an extensive green roof.

The solubility of benzene in linear polyethylene melts was estimated via Monte Carlo simulations using a united-atom molecular model at temperatures between 373 and 573 K, in the infinite dilution limit. The excess chemical potential of the solute was evaluated with the direct particle deletion (DPD) method, whose rigorous derivation is presented here in detail: in this scheme, the benzene molecule united atoms are converted to hard spheres and then removed from the polymer system. The simulations were carried out in the N(1)N(2)PT ensemble using advanced Monte Carlo moves to equilibrate the polymeric phase. The evaluation of the accessible volume fraction for the "hard sphere" solute molecule required by the DPD method was performed analytically. The effect of the value of the arbitrary hard sphere diameter, d, on the computed thermodynamic quantities was determined, allowing us to establish an optimal range for the system considered. The values of Henry's law constant are in good agreement with experimental data from the literature in the temperature range considered and are comparable to those obtained with the lattice fluid and PC(SAFT) equations of state for the same system.

Access to Structural Funds of the European Union for the realisation of infrastructural projects having a value in excess of 50 M€ requires advance preparation of economic and financial analyses including sensitivity and risk analyses for the probabilistic evaluation of uncertainties linked to the investment financing. This work illustrates the techniques and methods necessary in order to carry out such analyses, with reference to the case study of the Catania underground railway line. Structural Funds are one of the main European Union financial instruments contributing to the removal of economic and social imbalance among its regions, thus favoring economic and social cohesion. Council Regulation (EC) n. 1083/2006 establishes the procedure to obtain the Structural Funds co-financing infrastructural projects; when the value of the investment is over 50 M€, the procedure requires additional documentation in order to evaluate the project. The aim of this work is to illustrate some of the techniques that are necessary in order to carry out the analyses required for the drawing up of these documents, with particular reference to sensitivity and risk analyses. These are techniques that are able to evaluate, both the probability a project has of achieving a satisfactory economic-financial performance (in terms of Net Present Value or Internal Rate of Return on Capital) and the variability of the result as compared to the estimate carried out. Risk analysis, in particular, is performed by means of a methodology based on the Montecarlo method, a methodology of statistical simulation that is frequently used in the scientific field, and with reference to the actual case of the underground line project of the Catania Circumetnea Railway.

We consider the modeling of the dynamics of the chemostat at its very source. The chemostat is classically represented as a system of ordinary differential equations. Our goal is to establish a stochastic model that is valid at the scale immediately preceding the one corresponding to the deterministic model. At a microscopic scale we present a pure jump stochastic model that gives rise, at the macroscopic scale, to the ordinary differential equation model. At an intermediate scale, an approximation diffusion allows us to propose a model in the form of a system of stochastic differential equations. We expound the mechanism to switch from one model to another, together with the associated simulation procedures. We also describe the domain of validity of the different models.; Nous reprenons la modélisation de la dynamique du chemostat à sa source. Le chemostat est classiquement représenté par un système d'équations différentielles. Notre objectif est d'établir un modèle stochastique qui est valable à l'échelle qui précède immédiatement celle qui correspond au modèle déterministe. Partant d'une échelle microscopique, nous présentons un modèle stochastique de sauts purs qui conduit, à l'échelle macroscopique, au modèle d'équation différentielle. À une échelle intermédiaire, une approximation diffusion nous permet de proposer un modèle sous la forme d'un système d'équations différentielles stochastiques. Nous détaillons les techniques qui permettent de passer d'une échelle à une autre ainsi que de simuler ces différents modèles. Nous décrivons également les domaines de validité des différents modèles.

The aim of the work is to develop model and program for particle simulations working on laws of particle diffusion in expansion mode and, using approach of MonteCarlo, allows analyzing regularity in two-dimensional A+B → A reactions in case of B particle large mean free path, providing visualization of results and handy further processing of results, using data export ability. In the work are examined regularities in A+B → A reactions, special issues of these reactions, found approximate formula to determine velocity of reaction on centre of absorption surface using simulated data, developed program and made a lot of simulations of different reaction environments. Examined specific features of processed data and ways to enhance credibility and precision of results, also performed filtration of processed data to decrease specific of MonteCarlo method. Found out, that in comparison with nowadays personal computers, there is need for higher performance computing power to process simulation of particle interaction in acceptable timing.

In a free-market scenario, power system planning is affected by a significant degree of uncertainty about time and location of generating assets expansion. The paper contains a methodology for the evaluation of the flexibility, defined as the attitude of the transmission system to adapt, quickly and with limited costs, to every change, from the initial planning conditions, with a particular regard to the changes in generation. The method provides new global and local flexibility indices, based on technical and economical parameters, defined as Technical Uncertainty Scenarios Flexibility Index (T-USFI) and Technical Economical Uncertainty Scenarios Flexibility Index (TE-USFI). The T-USFI computation segment of methodology has been tested on simple networks.

The authors deal with the application of generalized extreme value theory (GEVT) to asynchronous transfer mode (ATM) buffer dimensioning. In particular, a general ATM system simulation model is defined to analyze a large variety of buffer behavior. The performance of the classical GEVT estimate procedure is evaluated in some critical cases by stressing its limits. To better cope with these cases, a modified version of the GEVT estimate procedure is proposed. Such a procedure is based on the combined utilization of the knowledge obtained from the classical Monte Carlo method and the extrapolating form of the GEVT estimator. The results show that this method allows some limitations of the GEVT approach to be overcome and a very good accuracy can be reached. >

We show the results of application of Differential SAR Interferometry to the MW 7.4, August 17, 1999, Izmit earthquake, Western Turkey. The differential interferogram is obtained using an interferometric ERS2 ascending pair with a time interval of 35 days (August 13th - September 17th). The fringe pattern clearly defines the coseismic displacement field extended in an area of about 100 km N-S and 120 km E-W. The analysis of the interferogram shows the right-lateral strike-slip movement on the activated section of the North Anatolian fault system. The maximum SAR-detected displacement ranges between 117.6 cm and 134.4 cm in the proximity of Gölcük. We invert SAR data for uniform dislocation on a single fault plane using a Montecarlo procedure, with the aim of testing a large set of a priori possible asperity distributions on the fault. We then use a forward modeling approach to evaluate the slip variability for the dislocation using additional constraints as surface offsets and seismicity distribution: in this case we allow unit cells to undergo different values of slip in order to refine the initial dislocation model. Misfits between SAR data and modeled slant range displacements are generally low for all our models (~ 12 cm). Our results indicate that slip is concentrated in the central-western part of the fault, in the upper 10-15 km, tapering to the fault tips. For the Izmit case, we note that a well constrained fault model can be obtained only integrating DInSAR data with additional observations. This is mainly due to an undersampling of the displacement field by DInSAR, caused by decorrelation and lack of image data.

Intravascular brachytherapy with beta sources has become a useful technique to prevent restenosis after cardiovascular intervention. In particular, the Beta-Cath high-dose-rate system, manufactured by Novoste Corporation, is a commercially available 90Sr 90Y source for intravascular brachytherapy that is achieving widespread use. Its dosimetric characterization has attracted considerable attention in recent years. Unfortunately, the short ranges of the emitted beta particles and the associated large dose gradients make experimental measurements particularly difficult. This circumstance has motivated the appearance of a number of papers addressing the characterization of this source by means of Monte Carlo simulation techniques.

Uncertainty analysis of coalbed methane (CBM) economic assessment is key to weakening the high potential risks of CBM exploration. In this paper, the uncertainty analysis method of CBM projects is created with montecarlo simulation. Firstly for discovering the risk origins of CBM economy, the main uncertainty factors are analyzed and the risk transformation process model of main uncertainty factors is built. Secondly, compling with above process model, CBM economic risk analysis algorithm steps are discussed detailed. Finally, by an example, the CBM economic risk of target area is cacluated. The results show that montecarlo method is an efficient for uncertainty analysis of CBM assessment.