Search results for "swa"

Optimal power flow based on glow worm-swarm optimization for three-phase islanded microgrids

2014

This paper presents an application of the Glowworm Swarm Optimization method (GSO) to solve the optimal power flow problem in three-phase islanded microgrids equipped with power electronics dc-ac inverter interfaced distributed generation units. In this system, the power injected by the distributed generation units and the droop control parameters are considered as variables to be adjusted by a superior level control. Two case studies with different optimized parameters have been carried out on a 6-bus test system. The obtained results showed the effectiveness of the proposed approach and overcomes the problem of OPF in islanded microgrids showing loads unbalance.

A shoreline boundary condition for a highly nonlinear Boussinesq model for breaking waves

2012

Abstract A physically based strategy was used to model swash zone hydrodynamics forced by breaking waves within a Boussinesq type of model. The position and the velocity of the shoreline were determined continuously in space by solving the physically-based equations of the shoreline motion; moreover, a fixed grid method, with a wet–dry interface, was adopted for integrating the Boussinesq model. The numerical stability of the model was improved by means of an extrapolation method. To validate the proposed methodology, the classical analytical solution for the shoreline motion of a monochromatic wave train over a plane beach was considered. The comparison between the analytical and numerical…

A revision of the new world species of Polytrichophora Cresson and Facitrichophora, new genus (Diptera, Ephydridae)

2012

The New World species of Polytrichophora Cresson and Fascitrichophora new genus, are revised. Fifteen new species are described (type locality in parenthesis): Fascitrishophora atrella sp. n. (Costa Rica. Guanacaste: Murciélago [10°56.9’N, 85°42.5’W; sandy mud flats around mangrove inlet]), F. carvalhorum sp.n. (Brazil. São Paulo: Praia Puruba [23°21’S, 44°55.6’W; beach]), F. manza sp. n. (Trinidad and Tobago. Trinidad. St. Andrew: Lower Manzanilla (12 km S; 10°24.5’N, 61°01.5’W), bridge over Nariva River), F. panama sp. n. (Panama. Darien: Garachine [8°04’N, 78°22’W]), Polytrichophora adarca sp. n…

Iatrogene Ösophagusperforation bei transösophagealer Echokardiographie

2004

History A 65-year-old patient underwent transesophageal echocardiography which caused a perforation of the upper esophagus. Three months after esophagostomy and gastrostomy the reconstruction was accomplished by a colon interposition graft. The patient postoperatively developed an ischemic necrosis of the graft, followed by a cervical fistula. Food intake and swallowing became impossible. Diagnosis X-ray examinations revealed the cervical fistula and a stenotic colon graft. Treatment and course The retrosternal colon graft was replaced by a gastric interposition graft, which was anastomosed with the cervical esophagus. The postoperative follow-up was normal at first. Increasing retention of…

Volatility transmission patterns and terrorist attacks

2009

The objective of this study is to analyze volatility transmission between the US and Eurozone stock markets considering the effects of the September 11, March 11 and July 7 financial crises. In order to do this, we use a multivariate GARCH model and take into account the asymmetric volatility phenomenon, the non-synchronous trading problem and the crises themselves. Moreover, a graphical analysis of the Asymmetric Volatility Impulse-Response Functions (AVIRF) is introduced, which takes into consideration the crisis effect. Results suggest that there is bidirectional and asymmetric volatility transmission and show the different impact that terrorist attacks had on both markets. El objetivo d…

A computational proposal for a robust estimation of the Pareto tail index: An application to emerging markets

2022

Abstract In this work, we backtest and compare, under the VaR risk measure, the fitting performances of three classes of density distributions (Gaussian, Stable and Pareto) with respect to three different types of emerging markets: Egypt, Qatar and Mexico. We also propose a new technique for the estimation of the Pareto tail index by means of the Threshold Accepting (TAVaR) and the Hybrid Particle Swarm Optimization algorithm (H-PSOVaR). Furthermore, we test the accuracy and robustness of our estimates demonstrating the effectiveness of the proposed approach.

Debating Europe: Effects of the “Eurovision Debate” on EU Attitudes of Young German Voters and the Moderating Role Played by Political Involvement

2016

In the run-up to the elections to the European Parliament in 2014, EU citizens had the unprecedented opportunity to watch televised debates between the candidates running for president of the European Commission. The most important debate was the so-called "Eurovision debate", which was broadcasted in almost all EU member states. In this study we explore the responses of a sample of 110 young German voters, who watched this debate, to the candidates' messages and whether exposure to the debate caused a shift in the respondents' attitudes towards the EU. Combining data from a quasi-experiment, real-time response data, and data from a content analysis of the debate, we find that respondents' …

Trading with Asymmetric Volatility Spillovers

2007

:  We study the profitability of trading strategies based on volatility spillovers between large and small firms. By using the Volatility Impulse-Response Function of Lin (1997) and its extensions, we detect that any volatility shock coming from small companies is important to large companies, but the reverse is only true for negative shocks coming from large firms. To exploit these asymmetric patterns in volatility, different trading rules are designed based on the inverse relationship existing between expected return and volatility. We find that most strategies generate excess after-transaction cost profits, especially after very bad news and very good news coming from large or small firm…

Sviluppi recenti e nuove tecnologie per la stima dei fabbisogni irrigui in ambiente mediterraneo

2008

Isometric Words Based on Swap and Mismatch Distance

2023

An edit distance is a metric between words that quantifies how two words differ by counting the number of edit operations needed to transform one word into the other one. A word f is said isometric with respect to an edit distance if, for any pair of f-free words u and v, there exists a transformation of minimal length from u to v via the related edit operations such that all the intermediate words are also f-free. The adjective 'isometric' comes from the fact that, if the Hamming distance is considered (i.e., only mismatches), then isometric words are connected with definitions of isometric subgraphs of hypercubes. We consider the case of edit distance with swap and mismatch. We compare it…