569 research outputs found
Caribbean Plate margin evolution: constraints and current problems
Oceanic crust was generated at multiple spreading centres during the Jurassic and Early Cretaceous, forming a âproto-Caribbeanâ oceanic domain. During the Cretaceous, part of that crustal domain thickened into an oceanic plateau, of petrologic Mid-Ocean Ridge (MOR) to Ocean Island Basalt (OIB) affinity. Simultaneously, the South and North American continental plates developed rifting and tholeiitic magmatism in the Middle America region (Venezuela and Cuba). The rifting created space for the proto-Caribbean oceanic domain. Petrological and regional correlations suggest that, beginning in the Cretaceous, the proto-Caribbean domain was involved into two main stages of subduction, referred to as first and second âeo-Caribbeanâ phases. Each phase is characterized by oblique convergence. The older (mid-Cretaceous) stage, involved in subduction (probably eastward dipping) of thin proto-Caribbean lithosphere, with generation of Island Arc Tholeiitic (IAT) and Calc-Alkaline (CA) magmatism, accompanied by high pressure - low temperature (HP - LT) metamorphic effects, and formation of arc units and ophiolitic melanges (Guatemala, Cuba, Hispaniola and Puerto Rico, in the northern margin; Venezuela in the southern). The Late Cretaceous second stage consisted of westward dipping intra-oceanic subduction; it is recorded by tonalitic arc magmatism related to the onset of the Aves - Lesser Antilles arc system. Since the Late Cretaceous, the inner undeformed portions of the Caribbean oceanic plateau (i.e. the Colombian and Venezuelan Basins) were trapped east of the Pacific subduction of the Chortis, Chorotega and Choco blocks, ultimately building the Central American Isthmus. From Tertiary to Present, continuous eastward movement of the Caribbean Plate with respect to the Americas, gave rise to transpression along both the northern and southern margins, marked by scattered and dismembered ophiolitic terranes
A Multi-Objective Method for Short-Term Load Forecasting in European Countries
In this paper we present a novel method for daily short-term load forecasting, belonging to the class of âsimilar shapeâ algorithms. In the proposed method, a number of parameters are optimally tuned via a multi-objective strategy that minimizes the error and the variance of the error, with the objective of providing a final forecast that is at the same time accurate and reliable. We extensively compare our algorithm with other state-of-the-art methods. In particular, we apply our approach upon publicly available data and show that the same algorithm accurately forecasts the load of countries characterized by different size, different weather conditions, and generally different electrical load profiles, in an unsupervised manner
dynamic analysis of bernoulli euler beams with interval uncertainties under moving loads
Abstract This paper deals with the dynamic analysis of Bernoulli-Euler beams with uncertain parameters crossed by moving loads. Uncertainties associated with mass density, Young's modulus and load velocity are modeled as interval variables with given lower bounds and upper bounds. In order to evaluate the bounds of the interval displacement of the beam, an efficient procedure based on the use of the classical modal superposition method in conjunction with the improved interval analysis via extra unitary interval is developed. The key idea is to seek the bounds of the response by exploring just a few combinations of the endpoints of the uncertain parameters appropriately selected based on those yielding the minimum and maximum values of the interval natural frequencies
A comparison between standard and crossfeed monopulse radars in presence of rough sea scattering and ship movements
Monopulse radars are widely used in tracking systems, due to their relative
simplicity and theoretical precision, but the presence of multipath
impairs the tracking capabilities of these radars, especially when multipath
signals are strong, as in a naval environment. A special monopulse
setup, the crossfeed, has been proposed in the past to provide an automatic
cancellation from smooth sea multipath. In this contribution,
the performances of such a system are analyzed in presence of rough sea
scattering and compared with those of a standard monopulse setup. Particular
attention is devoted to performance degradations due to possible
phase errors in the passive network implementing the comparator and
due to ship rolling and pitching. This latter requires a full 3D monopulse
simulator for its correct evaluation
Analysis of Structural Performance in the Framework of Imprecise Probabilities
The analysis of structures with uncertain properties modeled as random variables with imprecise Probability Density Function (PDF) characterized by interval basic parameters (mean-value, variance, etc.) is addressed. A novel procedure able to provide approximate explicit expressions of the bounds of the interval mean-value and variance of the random stresses is proposed. The procedure stems from the joint application of the Improved Interval Analysis via Extra Unitary Interval and the Rational Series Expansion, introduced in the literature by the last two authors. The influence of imprecision of the PDF of the input parameters on structural performance is also investigated. For validation purposes, a 3D truss structure with uncertain Youngs moduli is analyzed
Clustering analysis of the electrical load in European countries
In this paper we used clustering algorithms to compare the typical load profiles of different European countries in different day of the weeks. We find out that better results are obtained if the clustering is not performed directly on the data, but on some features extracted from the data. Clustering results can be exploited by energy providers to tailor more attractive time-varying tariffs for their customers. In particular, despite the relevant differences among the several compared countries, we obtained the interesting result of indentifying a single feature that is able to distinguish weekdays from holidays and pre-holidays in all the examined countries
A Software Architecture Assisting Workflow Executions on Cloud Resources
An enterprise providing services handled by means of workflows needs to monitor and control their execution, gather usage data, determine priorities, and properly use computing cloud-related resources. This paper proposes a software architecture that connects unaware services to components handling workflow monitoring and management concerns. Moreover, the provided components enhance dependability of services while letting developers focus only on the business logic
From trauma to aggression: an empirical study on the relationship between interpersonal trauma, attachment styles and aggressive tendencies among adults
The purpose of this study was to examine the relationships between traumatic experiences, insecure attachment styles and psychiatric symptoms in adulthood. Self-report measures concerning trauma, attachment styles and psychopathology were administered to 59 adults (33.9% males, 66.1% females) ranging in age from 18 to 61 years old. Results showed that traumatic experiences were associated with insecure attachment styles and psychopathology, in particular concerning aggressive tendencies. Findings of the study suggest that the exploration of past experiences and current attachment relationships, in terms of interpersonal functioning, may be crucial for understanding aggressiveness
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