Estimating the Probability of a Rare Event Over a Finite Time Horizon

We study an approximation for the zero-variance change of measure to estimate the probability of a rare event in a continuous-time Markov chain. The rare event occurs when the chain reaches a given set of states before some fixed time limit. The jump rates of the chain are expressed as functions of a rarity parameter in a way that the probability of the rare event goes to zero when the rarity parameter goes to zero, and the behavior of our estimators is studied in this asymptotic regime. After giving a general expression for the zero-variance change of measure in this situation, we develop an approximation of it via a power series and show that this approximation provides a bounded relative error when the rarity parameter goes to zero. We illustrate the performance of our approximation on small numerical examples of highly reliableMarkovian systems. We compare it to a previously proposed heuristic that combines forcing with balanced failure biaising. We also exhibit the exact zero-variance change of measure for these examples and compare it with these two approximations

Efficient Approach for OS-CFAR 2D Technique Using Distributive Histograms and Breakdown Point Optimal Concept applied to Acoustic Images

In this work, a new approach to improve the algorithmic efficiency of the Order Statistic-Constant False Alarm Rate (OS-CFAR) applied in two dimensions (2D) is presented. OS-CFAR is widely used in radar technology for detecting moving objects as well as in sonar technology for the relevant areas of segmentation and multi-target detection on the seafloor. OS-CFAR rank orders the samples obtained from a sliding window around a test cell to select a representative sample that is used to calculate an adaptive detection threshold maintaining a false alarm probability. Then, the test cell is evaluated to determine the presence or absence of a target based on the calculated threshold. The rank orders allows that OS-CFAR technique to be more robust in multi-target situations and less sensitive than other methods to the presence of the speckle noise, but requires higher computational effort. This is the bottleneck of the technique. Consequently, the contribution of this work is to improve the OS-CFAR 2D with the distributive histograms and the optimal breakdown point optimal concept, mainly from the standpoint of efficient computation. In this way, the OS-CFAR 2D on-line computation was improved, by means of speeding up the samples sorting problem through the improvement in the calculus of the statistics order. The theoretical algorithm analysis is presented to demonstrate the improvement of this approach. Also, this novel efficient OS-CFAR 2D was contrasted experimentally on acoustic images.Fil: Villar, Sebastian Aldo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; ArgentinaFil: Menna, Bruno Victorio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; ArgentinaFil: Torcida, Sebastián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; ArgentinaFil: Acosta, Gerardo Gabriel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Electromecánica. Grupo INTELYMEC; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentin

Real Costs Assessment of Solar-Hydrogen and Some Fossil Fuels by means of a Combustion Analysis

In order to compare solar-hydrogen and the most used fossil fuels, the evaluation of the "external" costs related to their use is required. These costs involve the environmental damage produced by the combustion reactions, the health problems caused by air pollution, the damage to land from fuel mining, and the environmental degradation linked to the global warming, the acid rains, and the water pollution. For each fuel, the global cost is determined as sum of the market price and of the correspondent external costs. In order to obtain a quantitative comparison, the quality of the different combustion reactions and the efficiency of the technologies employed in the specific application sector have to be considered adequately. At this purpose, an entropic index that considers the degree of irreversibility produced during the combustion process and the degradation of surroundings is introduced. Additionally, an environmental index that measures the pollutants released during the combustions is proposed. The combination of these indexes and the efficiency of the several technologies employed in four energy sectors have allowed the evaluation of the total costs, highlighting an economic scenario from which the real advantages concerning the exploitation of different energy carrier are determined

Ethnic identity, hegemony or resistance? Italian antifascism and the Giuseppe Garibaldi Memorial (Bahía Blanca, Argentina, 1927-1928)

El artículo aborda las relaciones entre espacio, política e identidad étnica en función de los sentidos atribuidos al monumento a Giuseppe Garibaldi de Bahía Blanca (Provincia de Buenos Aires, Argentina) por parte del antifascismo local. En particular, nos centramos en el proceso que condujo a su construcción, para lo que se ha estudiado la prensa local, así como la documentación disponible en el archivo de la Sociedad Italiana de Socorros Mutuos de Bahía Blanca. Interpretamos que el monumento representó a la vez una reivindicación identitaria, una demostración de hegemonía y una manifestación de resistencia. En general, nuestro aporte busca contribuir al campo de estudio de los monumentos como formas simbólicas espaciales de la política, mediante el análisis de un caso que pone en juego las nociones de identidad y poder en función de la localización, las dimensiones y las prácticas articuladas en torno al monumento a Garibaldi.Aquest article s’ocupa de les relacions entre espai, política i identitat ètnica en funció dels sentits atribuïts al monument a Giuseppe Garibaldi de Bahía Blanca (Província de Buenos Aires, Argentina) per part de l’antifeixisme local. En particular, ens centrem en el procés de la seva construcció, i per fer-ho s’ha estudiat la premsa local, així com la documentació disponible a l’arxiu de la Sociedad Italiana de Socorros Mutuos de Bahía Blanca. Interpretem que el monument representa alhora una reivindicació identitària, una demostració d’hegemonia i una manifestació de resistència. En general, el nostre treball pretén contribuir al camp d’estudi dels monuments com a formes simbòliques espacials de la política, mitjançant l’anàlisi d’un cas que posa en joc les nocions d’identitat i poder, en funció de la localització, les dimensions i les pràctiques articulades al voltant del monument a Garibaldi.Cet article traite des relations entre espace, politique et identité ethnique en fonction des sens attribués au monument à Giuseppe Garibaldi de Bahía Blanca (Province de Buenos Aires, Argentine) de la part de l’antifascisme local. En particulier, nous nous centrons sur le processus de sa construction, à partir de l’étude de la presse locale ainsi que de la documentation disponible dans les archives de la Sociedad Italiana de Socorros Mutuos de Bahía Blanca. Nous interprétons que le monument a représenté à la fois une revendication d’identité, une démonstration d’hégémonie et une manifestation de résistance. En général, ce travail cherche à apporter une contribution au domaine d’études des monuments en tant que formes symboliques spatiales de la politique à travers l’analyse d’un cas dans lequel les notions d’identité et de pouvoir entrent en jeu selon l’emplacement, les dimensions et les pratiques qui s’articulent autour du monument à Garibaldi.This article addresses the relationships between space, politics and ethnic identity based on the meanings given to the Giuseppe Garibaldi Memorial in Bahía Blanca (Buenos Aires Province, Argentina) by the local antifascism movement. Particularly, we focus on the process that led to the memorial’s construction. To this end, we studied the local press, as well as documents housed in the archive of the Sociedad de Socorros Mutuos de Bahía Blanca. We observe that the monument represented at the same time an identity claim, a demonstration of hegemony and a manifestation of resistance. Our general aim is to contribute to the field of monument analysis as symbolic spatial forms of politics through the study of a case that brings into play notions of identity and power in relation to localization, dimensions and practices developed around the Garibaldi Memorial.Fil: Cimatti, Bruno Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Humanidades. Centro de Estudios Regionales; Argentin

Fascism and catholicism in the southwest Buenos Aires (Bahía Blanca, Argentina, 1926-1939)

Las relaciones entre fascismo y catolicismo, más allá de su indudable relevancia en el marco de la historia italiana, representan un elemento de interés para abordar, en perspectiva local/regional, sus manifestaciones vinculadas a la difusión del fascismo entre las colectividades italianas diseminadas por el mundo.Para el caso argentino, de importante desarrollo en el campo de estudios del fascismo fuera de Italia, dichas vinculaciones no han sido analizadas sino de manera preliminar, relevándose necesario un abordaje “a ras del suelo” que permita recuperar las modalidades de cooperación que las articularon.A partir de un conjunto de fuentes –tanto argentinas como italianas– reconstruimos, desde la perspectiva de la sociabilidad política, los vínculos establecidos entre representantes del Fascio “Giulio Giordani” de Bahía Blanca (sudoeste de la provincia de Buenos Aires, Argentina) y sus instituciones satélites, y distintos representantes del catolicismo en el medio local.The relationships between Fascism and Catholicism, beyond their undeniable relevance in the Italian history, represent an Interesting element for approaching, from a local/ regional perspective, their manifestations related to the spread of Fascism among Italian communities scattered around the world. While the case of Argentina has seen significant developments in the study of Fascism outside Italy, the links between Fascism and Catholicism in this context have only been analyzed in a preliminary way. As a result, a “bottom-up” approach is necessary to recover the forms of cooperation that underpinned these links. Drawing from a range of sources from both Italy and Argentina, this study reconstructs the bonds that existed between members of the Fascio “Giulio Giordani” of Bahía Blanca (located in the southwest of Buenos Aires Province, Argentina) and its satellite institutions, and various Catholic agents in the local milieu, viewed through the lens of political sociability.Fil: Cimatti, Bruno Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Humanidades. Centro de Estudios Regionales; Argentin

Italian Fascism in Buenos Aires Province: An approach based on the cases of La Plata and Bahía Blanca (Argentina, 1926-1939)

Este artículo contribuye a los estudios sobre el desarrollo del fascismo en el interior argentino a partir del caso de la provincia de Buenos Aires entre 1926 y 1939. Para abordar un espacio de tal magnitud, y en virtud de tratarse de un acercamiento inicial, nos enfocamos en las ciudades de La Plata y Bahía Blanca. En base a fuentes argentinas e italianas, analizamos el desarrollo institucional de los fasci de ambas ciudades bonaerenses, las actividades que llevaron adelante y los vínculos que establecieron con la sociedad receptora. En conjunto, este estudio da un paso inicial hacia la superación del vacío provocado por la falta de estudios que realicen un abordaje del impacto del fascismo de la principal provincia argentina, cuestión que sí se ha desarrollado para otros casos nacionales.Este artigo faz uma contribuição significativa para o estudo do desenvolvimento do fascismo italiano no interior argentino, com foco específico no caso da provincia de Buenos Aires entre 1926 e 1939. Dada a vasta extensão geográfica deste estudo e considerando-o como uma exploração inicial, nossa atenção está direcionada para as ciudades de La Plata e Bahía Blanca. Com base em fontes argentinas e italianas, conduzimos uma análise abrangente da evolução institucional dos fasci nessas duas ciudades da provincia de Buenos Aires. Além disso, examinamos as varias atividades em que se envolveram e as conexões que estabeleceram com a sociedade local. No conjunto, este estudo representa um passo inicial na direção de preencher a lacuna criada pela falta de pesquisa sobre o impacto do fascismo na principal provincia argentina, um tema que foi explorado mais profundamente em outros contextos nacionais.This article makes a significant contribution to the field of Italian fascism’s development within the Argentine interior, focusing specifically on the case of the province of Buenos Aires between 1926 and 1939. Given the vast geographical scope of this study, and considering it serves as an initial exploration, our attention is directed towards the cities of La Plata and Bahía Blanca. Drawing upon both Argentine and Italian sources, we conduct a comprehensive examination of the institutional evolution of the fasci within these two cities in Buenos Aires province. Additionally, we delve into the various activities they engaged in and the connections they forged with the local society. Collectively, this study marks an initial stride towards addressing the gap created by the dearth of research concerning the impact of fascism in Argentina’s foremost province, a topic that has been explored in more depth for other national contexts.Fil: Cimatti, Bruno Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Humanidades. Centro de Estudios Regionales; Argentin

Italian colonial wars in Abyssinia before the Battle of Adwa: Bahta Hagos’ Revolt (1894) from the Perspective of Rosalia Pianavia-Vivaldi Bossiner

En el artículo, abordamos la interpretación realizada por Rosalia Pianavia-Vivaldi Bossiner de los primeros conflictos coloniales llevados adelante por Italia en el Cuerno de África contra distintos grupos nativos de la región histórica de Abisinia, con especial énfasis en la revuelta de Bahta Hagos de 1894.Para hacerlo, nos basamos en su libro Tre anni in Eritrea (1901), que relata las experiencias de la autora durante su estadía en Asmara entre 1893 y 1896. La obra constituyó la primera de su tipo escrita por una mujer en publicarse en Italia, lo que la convierte en un hito en el campo de la literatura de viajes colonial italiana. De esta manera, apuntamos a la recuperación de la mirada femenina sobre conflictos desarrollados en las fases tempranas de un colonialismo periférico en el concierto de potencias imperialistas europeas, como lo fue el italiano, contribuyendo desde los márgenes a la comprensión del fenómeno de las guerras coloniales de fines del siglo XIX y principios del XX.In this article, we focus on Rosalia Pianavia-Vivaldi Bossiner’s analysis of the earliest colonial conflicts carried on by Italy in the Horn of Africa against different native groups from the historical region of Abyssinia, with special focus on Bahta Hagos’ revolt in 1894. In order to achieve that, we based ourselves on her book Tre anni in Eritrea (1901), which describes the author’s experiences during her stay in Asmara between 1893 and 1896. Her work was the first of its type written by a woman that was ever published in Italy, what turns it into a major milestone in the field of Italian colonial travel writing. Thus, we aim to recover the female perspective on conflicts that took place in the early phases of a peripheral colonialism in the scene of European imperialist powers, such as the Italian case, contributing from the margin to the understanding of colonial wars at the turn of the twentieth century.Fil: Cimatti, Bruno Gerardo. Universidad Nacional del Sur. Departamento de Humanidades; Argentina. Universidad Nacional del Sur. Departamento de Humanidades. Centro de Estudios Regionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

On the robustness of fishman's bound-based method for the network reliability problem

International audienceStatic network unreliability computation is an NP-hard problem, leading to the use of Monte Carlo techniques to estimate it. The latter, in turn, suffer from the rare event problem, in the frequent situation where the system's unreliability is a very small value. As a consequence, specific rare event event simulation techniques are relevant tools to provide this estimation. We focus here on a method proposed by Fishman making use of bounds on the structure function of the model. The bounds are based on the computation of (disjoint) mincuts disconnecting the set of nodes and (disjoint) minpaths ensuring that they are connected. We analyze the robustness of the method when the unreliability of links goes to zero. We show that the conditions provided by Fishman, based on a bound, are only sufficient, and we provide more insight and examples on the behavior of the method

ddRAD-seq para el análisis de asociación genómico de los principales caracteres agronómicos y calidad organoléptica en melocotonero

PósterDouble-digest RAD sequencing (ddRAD-Seq) is a powerful method for SNP discovery at a genome-wide scale. It relies on breaking the genome into a certain size of DNA fragments using two restriction enzymes: i) one common cutter with a short recognition site and ii) a low frequency cutter having a large recognition motif . Amplification step in library preparation can introduce PCR artefacts. Those are expected to skew allele frequency by increasing homozygosity leading to false genotype calls. In this context, we carried out a comparison study between DNA-variants generated with duplicates and those generated after removing with either "'SAMtools:rmdup" or "Stacks clone filter". On the other hand, the accuracy of genetic variants identification is a crucial step towards understanding phenotypical traits and monitoring breeding programs. Thereby, a good combination of computational tools for alignment and variant calling is crucial to tackle the possible artifacts. In response to this challenge, three variant callers (BCFtools, Freebayes and GATK-HaplotypeCaller) were combined on top of the BWA-mem read mapper. SNPs derived from the intersection of these callers were used for a genome wide association study to genetic variants associated with agronomic and organoleptic traits (In this poster, we illustrate only one study case trait). A diverse set of 90 peach accessions were sampled from the Experimental Station of Aula Dei (CSIC) located at Zaragoza (northern of Spain). This germplasm collection includes landraces and modem breeding lines from different origins.EEA San PedroFil: Ksouri, Najla. Consejo Superior de Investigaciones Científicas (CSIC). Estación Experimental Aula Dei; EspañaFil: Sánchez, Gerardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Contreras-Moreira, Bruno. Consejo Superior de Investigaciones Científicas (CSIC). Estación Experimental Aula Dei; EspañaFil: Gogorcena Aoiz, Yolanda. Consejo Superior de Investigaciones Científicas (CSIC). Estación Experimental Aula Dei; Españ

A Second Law Analysis to Determine the Environmental Impact of Boilers Supplied by Different Fuels

A novel procedure to determine the environmental quality of boilers based on the combustion entropy degradation, the pollutants emission and the device efficiency is proposed. The entropy generation due to the chemical reaction was determined and then the irreversibilities on the external environment were first quantified. Successively, the entropy generation numbers of the combustion reactions were combined with the heat transfer process entropy generation of the boilers to consider the actual functioning conditions, in order to quantify the environmental damages by introducing an Environment Quality Index (EQI). A parametric study varying the heat exchanger efficiency, fluid flow rates and temperatures, for different fuel typologies, was performed to assess the environmental impact. Solar hydrogen was considered for its importance as future renewable energy carrier. The results showed that the highest EQI was produced by the natural gas, but if heat exchanger parameters are defined opportunely, the score gap with other fluids can be recovered. For hydrogen and coal decreasing the flue gases temperature or by increasing the flue gases mass flow rate can strongly improve the EQI index, whereas the gap recovery for Diesel is rather difficult