2,042 research outputs found
Has 1997 Asian Crisis increased Information Flows between International Markets?
The Asian crisis started on July 2, 1997 and caused turmoil in developed as well as emerging international stock markets. The objective of this paper is to analyse the movements and dynamic relationships among stock markets, together with their implications for information flows. We use the Morgan Stanley National and International Indexes (MSCI). These indexes refer to four geographic areas (Asia, Europe, North America and Latin America) for two homogeneous and non-overlapping time intervals. The econometric techniques used in this paper include the cointegration test, vector autoregression analysis, forecast error variance decomposition and impulse-response relationships. Our results show that: i) there are no multivariate cointegration relationships across markets, ii) the leadership role played by the U.S. became stronger after the crisis, iii) the response of Asian markets to external markets is more relevant than vice versa, especially after the crisis, iv) the degree of integration, in Phylaktis (1999) sense, between Asian and the rest of the international stock markets has increased after the crisis and, finally, v) the contagion effect determines significantly the dynamic relationships between international stock markets.Asian crisis, stock market, information flow, cointegration, VAR
Superconductivity in WO2.6F0.4 synthesized by reaction of WO3 with Teflon
WO3-xFx (x < 0.45) perovskite-like oxyfluorides were prepared by a chemically
reducing fluorination route using the polymer polytetrafluoroethylene (Teflon).
The symmetry of the crystal structures of WO3-xFx changes from monoclinic to
tetragonal to cubic as the fluorine content increases. Fluorine doping changes
insulating WO3 to a metallic conductor, and superconductivity (Tc = 0.4 K) was
discovered in the samples with fluorine contents of 0.41 < x < 0.45. This easy
fluorination method may be applicable to other systems and presents an
opportunity for finding new oxyfluoride superconductors.Comment: 9 pages, 3 figures, 2 tables. To be published in Phys Rev
Wavelet transforms for non-uniform speech recognition
An algorithm for nonuniform speech segmentation and its application in speech recognition systems is presented. A method based on the Modulated Gaussian Wavelet Transform based Speech Analyser (MGWTSA) and the subsequent parametrization block is used to transform a uniform signal into a set of nonuniformly separated frames, with the accurate information being fed into a speech recognition system. The algorithm needs a frame characterizing the signal where necessary, trying to reduce the number of frames per signal as much as possible, without an appreciable reduction in the recognition rate of the system.Peer ReviewedPostprint (published version
Monolingual and bilingual spanish-catalan speech recognizers developed from SpeechDat databases
Under the SpeechDat specifications, the Spanish member of SpeechDat consortium has recorded a Catalan database that includes one
thousand speakers. This communication describes some experimental work that has been carried out using both the Spanish and the
Catalan speech material.
A speech recognition system has been trained for the Spanish language using a selection of the phonetically balanced utterances from
the 4500 SpeechDat training sessions. Utterances with mispronounced or incomplete words and with intermittent noise were discarded.
A set of 26 allophones was selected to account for the Spanish sounds and clustered demiphones have been used as context dependent
sub-lexical units. Following the same methodology, a recognition system was trained from the Catalan SpeechDat database. Catalan
sounds were described with 32 allophones. Additionally, a bilingual recognition system was built for both the Spanish and Catalan
languages. By means of clustering techniques, the suitable set of allophones to cover simultaneously both languages was determined.
Thus, 33 allophones were selected. The training material was built by the whole Catalan training material and the Spanish material
coming from the Eastern region of Spain (the region where Catalan is spoken).
The performance of the Spanish, Catalan and bilingual systems were assessed under the same framework. The Spanish system exhibits
a significantly better performance than the rest of systems due to its better training. The bilingual system provides an equivalent
performance to that afforded by both language specific systems trained with the Eastern Spanish material or the Catalan SpeechDat
corpus.Peer ReviewedPostprint (published version
Extreme Value Theory versus traditional GARCH approaches applied to financial data: a comparative evaluation
Although stock prices fluctuate, the variations are relatively small and are frequently assumed to be normal distributed on a large time scale. But sometimes these fluctuations can become determinant, especially when unforeseen large drops in asset prices are observed that could result in huge losses or even in market crashes. The evidence shows that these events happen far more often than would be expected under the generalized assumption of normal distributed financial returns. Thus it is crucial to properly model the distribution tails so as to be able to predict the frequency and magnitude of extreme stock price returns. In this paper we follow the approach suggested by McNeil and Frey (2000) and combine the GARCH-type models with the Extreme Value Theory (EVT) to estimate the tails of three financial index returns DJI,FTSE 100 and NIKKEI 225 representing three important financial areas in the world.
Our results indicate that EVT-based conditional quantile estimates are much more accurate than those from conventional AR-GARCH models assuming normal or Student’s t-distribution innovations when doing out-of-sample estimation (within the insample estimation, this is so for the right tail of the distribution of returns)
Stress-wave analysis technique study on thick-walled type A302B steel pressure vessels, July 1968 - July 1969
Stress wave analysis and crack opening displacement to monitor subcritical crack growth for grade B alloy steel pressure vessel
Determinants of profitability in Spanish financial institutions. Comparing aided and non-aided entities
The last financial crisis has led to the greatest contribution of public funds ever made to Spanish banks. This paper studies why the need for support has been asymmetric, with not all of the institutions requiring aid. Based on profitability of assets (ROA), we determine using panel data econometric and logit response models the components of profit and loss accounts that generated profitability as well as the factors leading to some entities to ask for aid. The analyses show that before the beginning of the crisis there were significant differences between entities that needed aid and those that did not. The most profitable banks grounded their success in the traditional revenue components of financial institutions (such as margin on interest rates and commissions), as well as in revenues obtained from participated companies and extraordinary results. The model offers a tool to detect entities in difficulties in advance, reducing the financial and social costs of public interventions. The factors more impacting on profitability of Spanish institutions are also identifie
CFD modeling of a fixed-bed biofilm reactor coupling hydrodynamics and biokinetics
Peer ReviewedPostprint (author's final draft
Maximum distance separable 2D convolutional codes
Maximum distance separable (MDS) block codes and MDS 1D convolutional codes are the most robust codes for error correction within the class of block codes of a fixed rate and 1D convolutional codes of a certain rate and degree, respectively. In this paper, we generalize this concept to the class of 2D convolutional codes. For that, we introduce a natural bound on the distance of a 2D convolutional code of rate and degree , which generalizes the Singleton bound for block codes and the generalized Singleton bound for 1D convolutional codes. Then, we prove the existence of 2D convolutional codes of rate and degree that reach such bound when if , or if , by presenting a concrete constructive procedure
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