Neural Networks for Estimating Speculative Attacks Models.

Currency crises have been analyzed and modeled over the last few decades. These currency crises develop mainly due to a balance of payments crisis, and in many cases, these crises lead to speculative attacks against the price of the currency. Despite the popularity of these models, they are currently shown as models with low estimation precision. In the present study, estimates are made with first- and second-generation speculative attack models using neural network methods. The results conclude that the Quantum-Inspired Neural Network and Deep Neural Decision Trees methodologies are shown to be the most accurate, with results around 90% accuracy. These results exceed the estimates made with Ordinary Least Squares, the usual estimation method for speculative attack models. In addition, the time required for the estimation is less for neural network methods than for Ordinary Least Squares. These results can be of great importance for public and financial institutions when anticipating speculative pressures on currencies that are in price crisis in the markets.

A performance degradation evaluation method for a turbocharger in a diesel engine.

As one of the key systems of the marine power plant diesel engine, the turbocharger directly affects whether the diesel engine can continuously and stably provide the power required for the ship. Owing to a number of uncontrollable factors, such as harsh working conditions and complex structures, the turbocharger may have various failures, causing it to lose its intended function. At present, the fault diagnosis of the marine turbocharger has not been paid enough attention yet and in most cases, the method of 'ex post diagnosis' is still adopted. When analysing the nonlinear correspondence between the failure symptoms and failure causes, it is difficult for the existing theories to meet the actual diagnostic requirements. This paper introduces the concept of gas-path diagnosis into the condition monitoring for a marine turbocharger for the first time and proposes the flow capacity index which characterizes the flow capacity of the component and the isentropic efficiency index which characterizes the operating efficiency of the component as two dimensionless evaluation indicators for turbocharger health status. Moreover, the nonlinear mapping relationship between these two health parameters and the gas-path measurable parameters of the turbocharger is studied, and a novel performance degradation evaluation method for a turbocharger is established. The proposed method has been tested in three test cases where the degradation of a model turbocharger has been analysed. These case studies have illustrated that the proposed method can accurately isolate the degraded components and further quantify the degradation of the components.

Micro y macronutrientes en el ganado bovino de los llanos venezolanos y su posible relación con el origen del síndrome parapléjico del bovino / Determination of micro and macronutrients in the cattle of Venezuelan plains and their influence on the origin of bovine paraplegic syndrome

En el presente trabajo se ha determinado el status mineral de bovinos provenientes de 17 fincas de las zonas suroeste (Apure), central (Guárico) y sur (Bolívar) de Venezuela, con el fin de detectar deficiencias o toxicidades minerales. Se tomaron muestras de sangre y biopsias hepáticas durante los períodos de sequía y lluvia a un total de 374 animales en los años 1990-1992. Los macro y micronutrientes analizados fueron: sodio, potasio, cloro, magnesio, calcio total, calcio iónico, fósforo, cobre, cobalto, molibdeno y zinc, además de creatinina y glucosa. El promedio de los valores de los macronutrientes y creatinina se encuentran dentro del nivel normal aceptado en la literatura. Los valores promedio de glucosa están hacia el límite inferior de los valores normales en Bolívar y Guárico y por debajo del rango normal en Apure. Los micronutrientes, a excepción a excepción del cobre y el zinc (en Bolívar y Guárico), están dentro de los límites aceptados como normales. Con el propósito de analizar las variaciones estacionales en los macro y micronutrientes se estudió una población controlada de bovinos en una finca de cada Estado a los que se lo tomaron muestras en distintas épocas del año. Se encontró que: a) durante la época de sequía los valores de algunos elementos (magnesio, calcio y cobre) tienden a ser deficitarios, para luego recuperarse en la época de lluvias y b) la suplementación mineral y el tratamiento sanitario mejoraron la ganancia de peso que se observa entre el período de sequía y lluvia. Al comparar los valores de macro y micronutrientes de animales controles y animales diagnosticados con Síndrome Parapléjico del Bovino (SPB), se encontraron diferencias significativas en el magnesio y el fósforo sérico. Con respecto al cobre hepático en animales con SPB el promedio se ubicó en 74,8 ppm-gr, ligeramente inferior al nivel crítico de 75 ppm-gr reportado en la literatura. En resumen, el cuadro nutricional típico encontrado en animales con SPB fue: elevada movilización de fosfato desde los huesos (altos niveles séricos), hipomagnesemia e hipocupremia subclínica.