661 research outputs found

    Onto Exchange Rate's Short Run Impact on Oil Prices Dynamics: An OPEC Members' perspective

    Get PDF
    In this paper, we study the oil price formation for the purpose of understanding price reactions of OPEC member countries to changes in the exchange rate of the US dollar and prices of other members in the short run. The results suggested that there is a partial impact of exchange rates volatility on oil prices dynamics in short runs. Moreover, the study demonstrated that Saudi Arabia behaves as a leader in the OPEC structure market while it behaves differently when linked to other reference markets. Generally, Saudi Arabia behaves more potentially and more moderately than the other OPEC members in responding to change of references markets prices.oil prices, exchange rates pass through, OPEC countries

    New trading risk indexes: application of the shapley value in finance

    Get PDF
    The aim of this paper is to offer new risk indicators that enable one to classify securities of a portfolio according to their risk degrees. These indexes are issued from a new method of the covariance decomposition based on the Shapley Value. The risk indicators are computed via the well-known Gini coefficient, which is viewed as a new risk measure and compared with the traditional measures related with the modern theory of portfolio. These indicators yield suitable information, which could be used by private or institutional investors to trade strategies on market portfolio.

    Decomposition of Gini and the generalized entropy inequality measures

    Get PDF
    In this article we provide an overview of the Gini decomposition and the generalized entropy inequality measures, a free access to their computation, an application on French wages, and a different way than Dagum to demonstrate that the Gini index is a more convenient measure than those issued from entropy: Theil, Hirschman-Herfindahl and Bourguignon.

    Cyclical Mackey Glass Model for Oil Bull Seasonal

    Get PDF
    In this article, we propose an innovative way for modelling oil bull seasonals taking into account seasonal speculations in oil markets. Since oil prices behave very seasonally during two periods of the year (summer and winter), we propose a modification of Mackey Glass equation by taking into account the rhythm of seasonal frequencies. Using monthly data for WTI oil prices, Seasonal Cyclical Mackey Glass estimates indicate that seasonal interactions between heterogeneous speculators with different expectations may be responsible for pronounced swings in prices in both periods. Moreover, the seasonal frequency  / 3(referring to a period of 6 months) appears to be persistent over time.Oil bull seasonal, Seasonal speculations, Heterogeneous agents model, Seasonal Cyclical Mackey Glass models.

    Hypothesis of Currency Basket Pricing of Crude Oil: An Iranian Perspective

    Get PDF
    The decline in the value of US dollar and the emergence of other currencies has opened the debate within OPEC, of whether it is possible to resort to the pricing of crude oil in alternative currencies. The debate was limited because of the inadequate liquidity of most other currencies. In this paper, we focus on the implications of the shift in the pricing of Iran’s crude oil to other currencies than the US dollar. The results demonstrated that the pricing for Iranian oil in US dollar had high reaction potential and responded moderately to the change in the exchange rate, when compared to the pricing in Euro and in Yen. Consequently, it appeared that stability on the financial market led to partial stability in the oil market.Crude Oil Pricing, Currency Basket, OPEC, Exchange Rate of Dollar, Euros, Yen.

    Validation of the acquisition algorithms for FSSCat’s Soil Moisture product

    Full text link
    Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2023, Tutors: Yolanda Sola, Adrian Perez-Portero, Adriano Jose CampsThis essay presents a validation of two months (October-November 2020) of soil moisture retrieved by the FSSCat mission by comparing it with the ESA Climate Change Initiative mission (ESA CII) dataset. A data processing pipeline, along with various statistical tests, was designed to detect disparities between the two datasets. The results with RMSE, Bias, and ubRMSE revealed notable discrepancies in some regions, such as Russia, with values of 0.1 m3/m3 for the ubRMSE. In general, FSSCat’s data has underestimated measurements compared to ESA CII’s dataset. These discrepancies can be attributed to instrumental errors, the presence of ice in certain regions, and uncertainties in the re-gridding method

    Design of a Machine Learning-based Approach for Fragment Retrieval on Models

    Full text link
    [ES] El aprendizaje automĂĄtico (ML por sus siglas en inglĂ©s) es conocido como la rama de la inteligencia artificial que reĂșne algoritmos estadĂ­sticos, probabilĂ­sticos y de optimizaciĂłn, que aprenden empĂ­ricamente. ML puede aprovechar el conocimiento y la experiencia que se han generado durante años en las empresas para realizar automĂĄticamente diferentes procesos. Por lo tanto, ML se ha aplicado a diversas ĂĄreas de investigaciĂłn, que estudian desde la medicina hasta la ingenierĂ­a del software. De hecho, en el campo de la ingenierĂ­a del software, el mantenimiento y la evoluciĂłn de un sistema abarca hasta un 80% de la vida Ăștil del sistema. Las empresas, que se han dedicado al desarrollo de sistemas software durante muchos años, han acumulado grandes cantidades de conocimiento y experiencia. Por lo tanto, ML resulta una soluciĂłn atractiva para reducir sus costos de mantenimiento aprovechando los recursos acumulados. EspecĂ­ficamente, la RecuperaciĂłn de Enlaces de Trazabilidad, la LocalizaciĂłn de Errores y la UbicaciĂłn de CaracterĂ­sticas se encuentran entre las tareas mĂĄs comunes y relevantes para realizar el mantenimiento de productos software. Para abordar estas tareas, los investigadores han propuesto diferentes enfoques. Sin embargo, la mayorĂ­a de las investigaciones se centran en mĂ©todos tradicionales, como la indexaciĂłn semĂĄntica latente, que no explota los recursos recopilados. AdemĂĄs, la mayorĂ­a de las investigaciones se enfocan en el cĂłdigo, descuidando otros artefactos de software como son los modelos. En esta tesis, presentamos un enfoque basado en ML para la recuperaciĂłn de fragmentos en modelos (FRAME). El objetivo de este enfoque es recuperar el fragmento del modelo que realiza mejor una consulta especĂ­fica. Esto permite a los ingenieros recuperar el fragmento que necesita ser trazado, reparado o ubicado para el mantenimiento del software. EspecĂ­ficamente, FRAME combina la computaciĂłn evolutiva y las tĂ©cnicas ML. En FRAME, un algoritmo evolutivo es guiado por ML para extraer de manera eficaz distintos fragmentos de un modelo. Estos fragmentos son posteriormente evaluados mediante tĂ©cnicas ML. Para aprender a evaluarlos, las tĂ©cnicas ML aprovechan el conocimiento (fragmentos recuperados de modelos) y la experiencia que las empresas han generado durante años. BasĂĄndose en lo aprendido, las tĂ©cnicas ML determinan quĂ© fragmento del modelo realiza mejor una consulta. Sin embargo, la mayorĂ­a de las tĂ©cnicas ML no pueden entender los fragmentos de los modelos. Por lo tanto, antes de aplicar las tĂ©cnicas ML, el enfoque propuesto codifica los fragmentos a travĂ©s de una codificaciĂłn ontolĂłgica y evolutiva. En resumen, FRAME estĂĄ diseñado para extraer fragmentos de un modelo, codificarlos y evaluar cuĂĄl realiza mejor una consulta especĂ­fica. El enfoque ha sido evaluado a partir de un caso real proporcionado por nuestro socio industrial (CAF, un proveedor internacional de soluciones ferroviarias). AdemĂĄs, sus resultados han sido comparados con los resultados de los enfoques mĂĄs comunes y recientes. Los resultados muestran que FRAME obtuvo los mejores resultados para la mayorĂ­a de los indicadores de rendimiento, proporcionando un valor medio de precisiĂłn igual a 59.91%, un valor medio de exhaustividad igual a 78.95%, una valor-F medio igual a 62.50% y un MCC (Coeficiente de CorrelaciĂłn Matthews) medio igual a 0.64. Aprovechando los fragmentos recuperados de los modelos, FRAME es menos sensible al conocimiento tĂĄcito y al desajuste de vocabulario que los enfoques basados en informaciĂłn semĂĄntica. Sin embargo, FRAME estĂĄ limitado por la disponibilidad de fragmentos recuperados para llevar a cabo el aprendizaje automĂĄtico. Esta tesis presenta una discusiĂłn mĂĄs amplia de estos aspectos asĂ­ como el anĂĄlisis estadĂ­stico de los resultados, que evalĂșa la magnitud de la mejora en comparaciĂłn con los otros enfoques.[CAT] L'aprenentatge automĂ tic (ML per les seues sigles en anglĂ©s) Ă©s conegut com la branca de la intel·ligĂšncia artificial que reuneix algorismes estadĂ­stics, probabilĂ­stics i d'optimitzaciĂł, que aprenen empĂ­ricament. ML pot aprofitar el coneixement i l'experiĂšncia que s'han generat durant anys en les empreses per a realitzar automĂ ticament diferents processos. Per tant, ML s'ha aplicat a diverses Ă rees d'investigaciĂł, que estudien des de la medicina fins a l'enginyeria del programari. De fet, en el camp de l'enginyeria del programari, el manteniment i l'evoluciĂł d'un sistema abasta fins a un 80% de la vida Ăștil del sistema. Les empreses, que s'han dedicat al desenvolupament de sistemes programari durant molts anys, han acumulat grans quantitats de coneixement i experiĂšncia. Per tant, ML resulta una soluciĂł atractiva per a reduir els seus costos de manteniment aprofitant els recursos acumulats. EspecĂ­ficament, la RecuperaciĂł d'Enllaços de Traçabilitat, la LocalitzaciĂł d'Errors i la UbicaciĂł de CaracterĂ­stiques es troben entre les tasques mĂ©s comunes i rellevants per a realitzar el manteniment de productes programari. Per a abordar aquestes tasques, els investigadors han proposat diferents enfocaments. No obstant aixĂČ, la majoria de les investigacions se centren en mĂštodes tradicionals, com la indexaciĂł semĂ ntica latent, que no explota els recursos recopilats. A mĂ©s, la majoria de les investigacions s'enfoquen en el codi, descurant altres artefactes de programari com sĂłn els models. En aquesta tesi, presentem un enfocament basat en ML per a la recuperaciĂł de fragments en models (FRAME). L'objectiu d'aquest enfocament Ă©s recuperar el fragment del model que realitza millor una consulta especĂ­fica. AixĂČ permet als enginyers recuperar el fragment que necessita ser traçat, reparat o situat per al manteniment del programari. EspecĂ­ficament, FRAME combina la computaciĂł evolutiva i les tĂšcniques ML. En FRAME, un algorisme evolutiu Ă©s guiat per ML per a extraure de manera eficaç diferents fragments d'un model. Aquests fragments sĂłn posteriorment avaluats mitjançant tĂšcniques ML. Per a aprendre a avaluar-los, les tĂšcniques ML aprofiten el coneixement (fragments recuperats de models) i l'experiĂšncia que les empreses han generat durant anys. Basant-se en l'aprĂ©s, les tĂšcniques ML determinen quin fragment del model realitza millor una consulta. No obstant aixĂČ, la majoria de les tĂšcniques ML no poden entendre els fragments dels models. Per tant, abans d'aplicar les tĂšcniques ML, l'enfocament proposat codifica els fragments a travĂ©s d'una codificaciĂł ontolĂČgica i evolutiva. En resum, FRAME estĂ  dissenyat per a extraure fragments d'un model, codificar-los i avaluar quin realitza millor una consulta especĂ­fica. L'enfocament ha sigut avaluat a partir d'un cas real proporcionat pel nostre soci industrial (CAF, un proveĂŻdor internacional de solucions ferroviĂ ries). A mĂ©s, els seus resultats han sigut comparats amb els resultats dels enfocaments mĂ©s comuns i recents. Els resultats mostren que FRAME va obtindre els millors resultats per a la majoria dels indicadors de rendiment, proporcionant un valor mitjĂ  de precisiĂł igual a 59.91%, un valor mitjĂ  d'exhaustivitat igual a 78.95%, una valor-F mig igual a 62.50% i un MCC (Coeficient de CorrelaciĂł Matthews) mig igual a 0.64. Aprofitant els fragments recuperats dels models, FRAME Ă©s menys sensible al coneixement tĂ cit i al desajustament de vocabulari que els enfocaments basats en informaciĂł semĂ ntica. No obstant aixĂČ, FRAME estĂ  limitat per la disponibilitat de fragments recuperats per a dur a terme l'aprenentatge automĂ tic. Aquesta tesi presenta una discussiĂł mĂ©s Ă mplia d'aquests aspectes aixĂ­ com l'anĂ lisi estadĂ­stica dels resultats, que avalua la magnitud de la millora en comparaciĂł amb els altres enfocaments.[EN] Machine Learning (ML) is known as the branch of artificial intelligence that gathers statistical, probabilistic, and optimization algorithms, which learn empirically. ML can exploit the knowledge and the experience that have been generated for years to automatically perform different processes. Therefore, ML has been applied to a wide range of research areas, from medicine to software engineering. In fact, in software engineering field, up to an 80% of a system's lifetime is spent on the maintenance and evolution of the system. The companies, that have been developing these software systems for a long time, have gathered a huge amount of knowledge and experience. Therefore, ML is an attractive solution to reduce their maintenance costs exploiting the gathered resources. Specifically, Traceability Link Recovery, Bug Localization, and Feature Location are amongst the most common and relevant tasks when maintaining software products. To tackle these tasks, researchers have proposed a number of approaches. However, most research focus on traditional methods, such as Latent Semantic Indexing, which does not exploit the gathered resources. Moreover, most research targets code, neglecting other software artifacts such as models. In this dissertation, we present an ML-based approach for fragment retrieval on models (FRAME). The goal of this approach is to retrieve the model fragment which better realizes a specific query in a model. This allows engineers to retrieve the model fragment, which must be traced, fixed, or located for software maintenance. Specifically, the FRAME approach combines evolutionary computation and ML techniques. In the FRAME approach, an evolutionary algorithm is guided by ML to effectively extract model fragments from a model. These model fragments are then assessed through ML techniques. To learn how to assess them, ML techniques takes advantage of the companies' knowledge (retrieved model fragments) and experience. Then, based on what was learned, ML techniques determine which model fragment better realizes a query. However, model fragments are not understandable for most ML techniques. Therefore, the proposed approach encodes the model fragments through an ontological evolutionary encoding. In short, the FRAME approach is designed to extract model fragments, encode them, and assess which one better realizes a specific query. The approach has been evaluated in our industrial partner (CAF, an international provider of railway solutions) and compared to the most common and recent approaches. The results show that the FRAME approach achieved the best results for most performance indicators, providing a mean precision value of 59.91%, a recall value of 78.95%, a combined F-measure of 62.50%, and a MCC (Matthews correlation coefficient) value of 0.64. Leveraging retrieved model fragments, the FRAME approach is less sensitive to tacit knowledge and vocabulary mismatch than the approaches based on semantic information. However, the approach is limited by the availability of the retrieved model fragments to perform the learning. These aspects are further discussed, after the statistical analysis of the results, which assesses the magnitude of the improvement in comparison to the other approaches.MarcĂ©n Terraza, AC. (2020). Design of a Machine Learning-based Approach for Fragment Retrieval on Models [Tesis doctoral]. Universitat PolitĂšcnica de ValĂšncia. https://doi.org/10.4995/Thesis/10251/158617TESI

    Quanta aigua més que terra hi ha al nostre planeta?

    Get PDF
    Hi havia una vegada una escola. I a l'escola, hi havia una classe d'educaciĂł infantil que es deia falcons. I a la classe dels falcons, hi havia vint-i-cinc nens i nenes que volien saber-ho tot sobre el mars i els oceans. AixĂ­ doncs, van començar a fer-se preguntes, a consensuar-les, a valorar les possibilitats que tenien de trobar-hi resposta, a gaudir estudiant i parlant de ciĂšncies amb les seves famĂ­lies. Un dia va sorgir la pregunta Quanta aigua mĂ©s que terra hi ha al nostre planeta?'' i en el procĂ©s de trobar-hi la resposta, els nens i les nenes van trobar-se amb fraccions, percentatges, metres quadrats, vĂšrtexs, arestes, cares, metres cĂșbics i nombres molt i molt grans.Once upon a time, there was a school. And in this school, there was a classroom named hawks. And the twenty five children from the classroom named hawks wanted to know everything there was to know about oceans and seas. Therefore they began to ask some questions, to make some agreements, to evaluate their possibilities to obtain answers. And they had a good time studying and talking about science at home. One day, the question was: How much more water than land is there on Earth?, and in the process of finding the answer, they encountered fractions, percentages, square meters, vertices, edges, facets, cubic meters and some very big numbers

    DĂ©compositions des mesures d’inĂ©galitĂ© : le cas des coefficients de Gini et d'entropie

    Get PDF
    Les mesures d’inĂ©galitĂ© du revenu rassemblent deux types d’indicateurs dĂ©composables : les indices dĂ©composables en sous-populations et les indices dĂ©composables en sources de revenu. Les premiers permettent de partager l’inĂ©galitĂ© totale en une inĂ©galitĂ© intragroupe et une inĂ©galitĂ© intergroupe et les seconds d’attribuer Ă  chaque facteur de revenu (revenu du travail, revenu du capital, taxes, etc.) une part de l’inĂ©galitĂ© totale. Dans cet article, nous examinons d’une part la construction de ces techniques et d’autre part nous relatons les dĂ©bats auxquels elles ont abouti et plus particuliĂšrement celui de la convergence vers un emploi simultanĂ© des deux types de dĂ©composition.DĂ©compositions ; Entropie ; Gini
    • 

    corecore