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In this paper, we describe an interactive web application (deaR-shiny) to measure efficiency and productivity using data envelopment analysis (DEA). deaR-shiny aims to fill the gap that currently exists in the availability of online DEA software offering practitioners and researchers free access to a very wide variety of DEA models (both conventional and fuzzy models). We illustrate how to use the web app by replicating the main results obtained by Carlucci, Cirà and Coccorese in 2018, who investigate the efficiency and economic sustainability of Italian regional airport by using two conventional DEA models, and the results given by Kao and Liu in their papers published in 2000 and 2003, who calculate the efficiency scores of university libraries in Taiwan by using a fuzzy DEA model because they treat missing data as fuzzy numbers.
Rafael Benítez; Vicente Coll-Serrano; Vicente Bolós. deaR-Shiny: An Interactive Web App for Data Envelopment Analysis. Sustainability 2021, 13, 6774 .
AMA StyleRafael Benítez, Vicente Coll-Serrano, Vicente Bolós. deaR-Shiny: An Interactive Web App for Data Envelopment Analysis. Sustainability. 2021; 13 (12):6774.
Chicago/Turabian StyleRafael Benítez; Vicente Coll-Serrano; Vicente Bolós. 2021. "deaR-Shiny: An Interactive Web App for Data Envelopment Analysis." Sustainability 13, no. 12: 6774.
This paper examines the interdependence between green financial instruments, represented by green bonds and green stocks, and a set of major conventional assets, such as Treasury, investment-grade and high-yield corporate bonds, general stocks, crude oil, and gold. To that end, a novel wavelet-based network approach that allows for assessing the degree of interconnection between green financial products and traditional asset classes across different investment horizons is applied. The empirical results show that green bonds are tightly linked to Treasury and investment-grade corporate bonds, while green stocks are strongly tied to general stocks, regardless of the specific time period and investment horizon considered. However, despite their common climate-friendly nature, there is no a remarkable association between green bonds and green stocks. This means that these green investments constitute basically two independent asset classes, with a distinct risk-return profile and aimed at a different type of investor. Furthermore, green financial products have a weak connection with high-yield corporate bonds and crude oil. These findings can have important implications for investors and policy makers in terms of investment decision, hedging strategies, and sustainability and energy policies.
Román Ferrer; Rafael Benítez; Vicente Bolós. Interdependence between Green Financial Instruments and Major Conventional Assets: A Wavelet-Based Network Analysis. Mathematics 2021, 9, 900 .
AMA StyleRomán Ferrer, Rafael Benítez, Vicente Bolós. Interdependence between Green Financial Instruments and Major Conventional Assets: A Wavelet-Based Network Analysis. Mathematics. 2021; 9 (8):900.
Chicago/Turabian StyleRomán Ferrer; Rafael Benítez; Vicente Bolós. 2021. "Interdependence between Green Financial Instruments and Major Conventional Assets: A Wavelet-Based Network Analysis." Mathematics 9, no. 8: 900.
In this paper we present a multi-criteria classification of Vocational and Educational Programs in Extremadura (Spain) during the period 2009–2016. This ranking has been carried out through the integration into a complete database of the detailed information of individuals finishing such studies together with their labor data. The multicriteria method used is TOPSIS together with a new decision support method for assessing the influence of each criterion and its dependence on the weights assigned to them. This new method is based on a worst-best case scenario analysis and it is compared to a well known global sensitivity analysis technique based on the Pearson's correlation ratio.
J.M. Conejero; J.C. Preciado; A.E. Prieto; M.C. Bas; V.J. Bolós. Applying data driven decision making to rank vocational and educational training programs with TOPSIS. Decision Support Systems 2020, 142, 113470 .
AMA StyleJ.M. Conejero, J.C. Preciado, A.E. Prieto, M.C. Bas, V.J. Bolós. Applying data driven decision making to rank vocational and educational training programs with TOPSIS. Decision Support Systems. 2020; 142 ():113470.
Chicago/Turabian StyleJ.M. Conejero; J.C. Preciado; A.E. Prieto; M.C. Bas; V.J. Bolós. 2020. "Applying data driven decision making to rank vocational and educational training programs with TOPSIS." Decision Support Systems 142, no. : 113470.
We introduce a new wavelet tool, the windowed scale index, to study the degree of non-periodicity of time series. The windowed scale index is based on some recently defined tools, such as the windowed scalogram and the scale index. This novel measure is appropriate for non-stationary time series whose characteristics change over time and, therefore, it can be applied to a wide variety of disciplines. Furthermore, we revise the concept of the scale index and pose a theoretical problem: it is known that if the scale index of a function is not zero then it is non-periodic, but if the scale index of a function is zero, then it is not proved that it has to be periodic. This problem is solved for the particular case of the Haar wavelet, reinforcing the interpretation of the windowed scale index as a useful tool to quantify non-periodicity. In addition, the applicability of this wavelet-based measure is illustrated through several examples, including an economic application which compares the non-periodicity of two major commodities in the world economy, such as crude oil and gold. Finally, we discuss the relationship between non-periodicity and unpredictability, comparing the windowed scale index with the sample entropy.
Vicente J. Bolós; Rafael Benítez; Román Ferrer. A New Wavelet Tool to Quantify Non-Periodicity of Non-Stationary Economic Time Series. Mathematics 2020, 8, 844 .
AMA StyleVicente J. Bolós, Rafael Benítez, Román Ferrer. A New Wavelet Tool to Quantify Non-Periodicity of Non-Stationary Economic Time Series. Mathematics. 2020; 8 (5):844.
Chicago/Turabian StyleVicente J. Bolós; Rafael Benítez; Román Ferrer. 2020. "A New Wavelet Tool to Quantify Non-Periodicity of Non-Stationary Economic Time Series." Mathematics 8, no. 5: 844.
In this paper, we introduce a new wavelet tool for studying the degree of non-periodicity of time series that is based on some recently defined tools, such as the \textit{windowed scalogram} and the \textit{scale index}. It is especially appropriate for non-stationary time series whose characteristics change over time and so, it can be applied to a wide variety of disciplines. In addition, we revise the concept of the scale index and pose a theoretical problem: it is known that if the scale index of a function is not zero then it is non-periodic, but if the scale index of a function is zero, then it is not proved that it has to be periodic. This problem is solved for the particular case of the Haar wavelet, thus reinforcing the interpretation and applicability of the scale index as a useful tool for measuring non-periodicity. Finally, we discuss the relationship between non-periodicity and unpredictability, comparing the new wavelet tool with the sample entropy.
Vicente J. Bolos; Rafael Benitez; Roman Ferrer. Quantifying non-periodicity of non-stationary time series through wavelets. 2019, 1 .
AMA StyleVicente J. Bolos, Rafael Benitez, Roman Ferrer. Quantifying non-periodicity of non-stationary time series through wavelets. . 2019; ():1.
Chicago/Turabian StyleVicente J. Bolos; Rafael Benitez; Roman Ferrer. 2019. "Quantifying non-periodicity of non-stationary time series through wavelets." , no. : 1.
A probabilistic discrete model for 2D protein crystal growth is presented. This model takesinto account the available space and can describe growing processes of a different nature due to theversatility of its parameters, which gives the model great flexibility. The accuracy of the simulation istested against a real recrystallization experiment, carried out with the bacterial protein SbpA fromLysinibacillus sphaericus CCM2177, showing high agreement between the proposed model and theactual images of the crystal growth. Finally, it is also discussed how the regularity of the interface(i.e., the curve that separates the crystal from the substrate) affects the evolution of the simulation.
Vicente J. Bolos; Rafael Benítez; Aitziber Eleta-Lopez; Jose L. Toca-Herrera. A Probabilistic Model for Crystal Growth Applied to Protein Deposition at the Microscale. Materials 2019, 12, 479 .
AMA StyleVicente J. Bolos, Rafael Benítez, Aitziber Eleta-Lopez, Jose L. Toca-Herrera. A Probabilistic Model for Crystal Growth Applied to Protein Deposition at the Microscale. Materials. 2019; 12 (3):479.
Chicago/Turabian StyleVicente J. Bolos; Rafael Benítez; Aitziber Eleta-Lopez; Jose L. Toca-Herrera. 2019. "A Probabilistic Model for Crystal Growth Applied to Protein Deposition at the Microscale." Materials 12, no. 3: 479.
This paper investigates the linkage between changes in 10-year government bond yields and stock returns for the major European countries in the time-frequency domain by using a number of cross-wavelet tools in the framework of the continuous wavelet transform, mainly the wavelet coherence and phase-difference. The results reveal that the degree of connection between 10-year bond rate movements and stock returns differs considerably among countries and also varies over time and depending on the time horizon considered. In particular, the UK shows the greatest interdependence between long-term interest rates and equity returns across time and frequencies, while the relationship is much weaker for several peripheral European countries such as Portugal, Ireland and Greece. The highest level of connection is observed for most countries since the onset of the recent global financial crisis. In addition, the significant linkage is mainly concentrated at investment horizons from one to 2 years.
Román Ferrer; Vicente J. Bolós; Rafael Benítez. Interest rate changes and stock returns: A European multi-country study with wavelets. International Review of Economics & Finance 2016, 44, 1 -12.
AMA StyleRomán Ferrer, Vicente J. Bolós, Rafael Benítez. Interest rate changes and stock returns: A European multi-country study with wavelets. International Review of Economics & Finance. 2016; 44 ():1-12.
Chicago/Turabian StyleRomán Ferrer; Vicente J. Bolós; Rafael Benítez. 2016. "Interest rate changes and stock returns: A European multi-country study with wavelets." International Review of Economics & Finance 44, no. : 1-12.
We analyze collocation methods for nonlinear homogeneous Volterra-Hammerstein integral equations with non-Lipschitz nonlinearity. We present different kinds of existence and uniqueness of nontrivial collocation solutions and we give conditions for such existence and uniqueness in some cases. Finally we illustrate these methods with an example of a collocation problem, and we give some examples of collocation problems that do not fit in the cases studied previously.
Vicente J. Bolos; Rafael Benitez. Existence and uniqueness of nontrivial collocation solutions of implicitly linear homogeneous Volterra integral equations. 2011, 1 .
AMA StyleVicente J. Bolos, Rafael Benitez. Existence and uniqueness of nontrivial collocation solutions of implicitly linear homogeneous Volterra integral equations. . 2011; ():1.
Chicago/Turabian StyleVicente J. Bolos; Rafael Benitez. 2011. "Existence and uniqueness of nontrivial collocation solutions of implicitly linear homogeneous Volterra integral equations." , no. : 1.
We discuss some aspects about the computation of kinematic, spectroscopic, Fermi and astrometric relative velocities that are geometrically defined in general relativity. Mainly, we state that kinematic and spectroscopic relative velocities only depend on the 4-velocities of the observer and the test particle, unlike Fermi and astrometric relative velocities, that also depend on the acceleration of the observer and the corresponding relative position of the test particle, but only at the event of observation and not around it, as it would be deduced, in principle, from the definition of these velocities. Finally, we propose an open problem in general relativity that consists on finding intrinsic expressions for Fermi and astrometric relative velocities avoiding terms that involve the evolution of the relative position of the test particle. For this purpose, the proofs given in this paper can serve as inspiration.Comment: 8 pages, 2 figure
Vicente J. Bolós. A note on the computation of geometrically defined relative velocities. General Relativity and Gravitation 2011, 44, 391 -400.
AMA StyleVicente J. Bolós. A note on the computation of geometrically defined relative velocities. General Relativity and Gravitation. 2011; 44 (2):391-400.
Chicago/Turabian StyleVicente J. Bolós. 2011. "A note on the computation of geometrically defined relative velocities." General Relativity and Gravitation 44, no. 2: 391-400.