Yolanda Villacampa - Academia.edu (original) (raw)
Papers by Yolanda Villacampa
Geomorphology, Apr 1, 2016
New methodology for describing the equilibrium beach profile applied to the Valencia's beaches. L... more New methodology for describing the equilibrium beach profile applied to the Valencia's beaches. L. Aragonés (a) , J.C. Serra (b) , Y. Villacampa (c) , J.M. Saval (d) , H. Tinoco (e) .
Mathematics
The problem of having ordinary differential equations (ODE) whose coefficients are unknown functi... more The problem of having ordinary differential equations (ODE) whose coefficients are unknown functions is frequent in several fields. Sometimes, it is possible to obtain samples of the values of these functions in different instants or spatial points. The present paper presents a methodology for the numeric solving of these ODE. There are approximations to the problem for specific cases of equations, especially in the case where the parameters correspond to constants. Other studies focus on the case in which the functions under consideration are linear or meet a certain condition. There are two main advantages of the proposed algorithm. First, it does not impose any condition over the data or the subsequent function from where these sample data are derived. Additionally, the methodology used in the functions modeling can control the possibility of overfitting in the function modeling. This is a crucial point in order to limit the influence of model biases in the numerical solution of ...
The Sustainable City IX, 2014
Bahía Norte, located in Alicante, is an artificial coastal area that suffers from erosion, which ... more Bahía Norte, located in Alicante, is an artificial coastal area that suffers from erosion, which disturbs the environment, the life and the economy of surrounding areas. In order to mitigate the erosion problem, a solution that provides coastal improvements and allows users to enjoy the structure is proposed. This solution develops artificial surfing reefs as a part of coastal protection management. An artificial surfing reef is not a new concept. However, it is an unknown and innovative idea in the Mediterranean Sea. Given that artificial surfing reefs are a reliable solution for the erosion suffered by the Mediterranean coastline. The project has five aims: controlling the sand loss, providing a recreational area for surfing, improving the security of the swimmers, revitalizing a depressed area and avoiding the visual noise of common structures of coastal defense. Artificial surfing reefs shape new driven current cells that cause an accretion in the shoreline by changing the pre-existing sea currents. Moreover, in order to improve surfing conditions, they fit the shape and height of the incoming waves. This research achieves an alteration of 420 meters of shore with a maximum salient formation of 50 meters, which fits perfectly to the situation of the artificial beach closed by groins. This research has also proved the importance of developing a careful study for the emplacement for this kind of reef being the distance from the structure to the shoreline one of the most determinant factors. It suggests that placing the artificial reef at 200 meters from the coast would be an adequate option.
International Journal of Computational Methods and Experimental Measurements, 2017
In this work, numerical models were obtained for describing the segregation phenomenon in lightwe... more In this work, numerical models were obtained for describing the segregation phenomenon in lightweight aggregate concrete. To that end, a numerical methodology based on the generation of geometric models of finite elements has been applied, selecting those that describe better this phenomenon. The use of lightweight aggregate concretes (LWC) allows greater design flexibility and substantial cost savings. It is also well known that it contributes to a positive impact on the energy consumption of a building due to the high-thermal resistance values. However, lightweight concretes are susceptible to present aggregate segregation due to density differences between its components during concrete vibration. Segregation in concrete may strongly affect the concrete global properties. This fact justifies the needs for the identification and quantification of this phenomenon, in order to estimate the concrete segregation experimentally, a LWC was mixed in laboratory conditions. Controlled segregation was caused applying different times of internal vibration in a cylinder specimen. The specimens were horizontally sectioned in order to obtain the density in each section because the segregation index can be estimated obtaining a relation by comparing the densities of the upper and lower parts. Firstly, ANOVA test was performed to determine the statistical significance (p<0.05) of the differences in the density of the different sections, differences in the aggregate type and differences in the time of concrete vibration. Results show that there is a significant difference of each section and there is no significant difference of each lightweight aggregate used to mix the concrete in spite of their different density. In order to model the segregation in the LWC, at first, linear models were considered and rejected because for not explaining the phenomenon. However, the application of numerical models shows good results to describe the phenomenon of segregation in LWC.
Computational Methods and Experimental Measurements XIX, 2019
The steel to concrete bond mechanism is critical to address the behaviour of reinforced concrete ... more The steel to concrete bond mechanism is critical to address the behaviour of reinforced concrete structural members. Although this mechanism can be compromised during a fire, it may be one of the least researched phenomena in concrete technology and is not addressed in the design codes and standards. In this work, we present a thorough review of the experimental data available on this topic, focusing on fibre-reinforced concrete. The data allow us to study the evolution of the bond strength as a function of three variables: the exposure temperature, the type of fibre and the volume fraction. A linear multiple regression is initially carried out, followed by a series of non-linear numerical models. These models are built using a methodology based on the finite element method combined with the formulation of the Galerkin method. The numerical models have been developed for different degrees of complexity. The error measurements obtained with the linear regression and the numerical models are compared in order to present a prediction model. The selected model is then validated for different values of the independent variables. This process supports the discussion of the influence that the independent variables have in the evolution of the bond strength between steel reinforcement and fibrereinforced concretes exposed to high temperatures.
In the hills of Azul (Province of Buenos Aires, Argentina) populations of Acacia nzelanoxylon R.B... more In the hills of Azul (Province of Buenos Aires, Argentina) populations of Acacia nzelanoxylon R.Brown are spread spontaneously. Although diffusion mechanisms are unknown, it is supposed that these populations derive from exotic cultivated trees introduced in the gardens and ornamental woods in the first decades of X X '~
Sustainability, 2021
One of the main problems faced in coastal management is the loss or destruction of beaches due to... more One of the main problems faced in coastal management is the loss or destruction of beaches due to erosion. A considerable diversity of factors is involved in coastal erosion, which makes it a complex system to study. The quality of the material that constitutes the beach, as well as the choice of appropriate materials for its nourishment are two of the main ones. Therefore, to make future nourishment projects more sustainable and durable, this work proposes a sediment quality classification based on the physical properties and wear process obtained through laboratory tests. The study of these variables, using principal component analysis, discriminant analysis and ANOVA, has divided the quality of 70 samples into three main groups. A Sediment Quality Classification Index (SQCI) is proposed, which categorizes the quality of the material into poor, regular or good, providing the coastal engineer with a simple tool to ensure more sustainable beach nourishments.
Marine Georesources & Geotechnology, 2020
Science of The Total Environment, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Marine Georesources & Geotechnology, 2017
The paper describes the training, validation, testing and application of models of artificial neu... more The paper describes the training, validation, testing and application of models of artificial neural networks (ANN) for computing the cross-shore beach profile of the sand beaches of the province of Valencia (Spain). Sixty ANN models were generated by modifying both the input variables as the number of neurons in the hidden layer. The input variables consist of wave data
Science of The Total Environment, 2019
Coastal erosion and lack of sediment supply are a serious global problem. It is therefore necessa... more Coastal erosion and lack of sediment supply are a serious global problem. It is therefore necessary to determine the depth of closure (DoC) of a beach-key parameter in the calculation of the sand volume and the location of the beach protection elements-in a precise way. For this reason, this work generates a numerical model based on Galerkin's formulation of finite elements that provides sufficient precision for the determination of DoC with a minimum investment. Thus, after the generation of three models in which the difference was the dependent variables, the least complex has been chosen. It is composed of the variables: median sediment size, wave height and period associated with the mean flow, as well as the angle that the mean flow forms with respect to the studied profile in absolute value (α). The selected model has been compared with the most commonly used models currently in use, having an average absolute error of 0.36 m and an average MAPE of <7.5%, which represents an improvement of >70% over current models. In addition, it presents a high stability, since after the random disturbance of all the input variables (up to 5%), the model error remains stable, increasing the MAPE by a maximum of 7.4% and the average absolute error by 0.15 m. Therefore, it is possible to use the model to infer the DoC in other study areas where the values of the variables are similar to those studied here, although the selected method can be extrapolated to other parts of the world.
International Journal of Sustainable Development and Planning, 2017
Numerous studies and theories have emerged for evaluating the quality of beaches using different ... more Numerous studies and theories have emerged for evaluating the quality of beaches using different parameters. In recent years in the European region, one of the most important aspects when evaluating a beach is the quality of water and sand. The quality of water is represented by the amount of Intestinal Enterococcus and Escherichia coli. This parameter is essential and others to obtain the Blue Flag, indicating that the user of the beach can swim safely. The European Directive 2006/7/EC establishes the limits of E. coli and Enterococcus that may exist in bathing water. However, it should be noted that each ecosystem is unique, and therefore the characteristics a beach are not the same per example if you are in an inland sea, or an ocean, or equal if they are close to an urban or a natural area. In this paper, 1,392 beaches in Spain have been analysed, and it has been observed that in the Mediterranean, the beaches have a lower concentration of bacteria than other areas. In addition, it appears that the sandy beaches and urban beaches have a higher content of bacteria that natural and gravel beaches.
International Journal of Sustainable Development and Planning, 2017
Tourism development in recent decades has involved a large urban development in coastal areas, wi... more Tourism development in recent decades has involved a large urban development in coastal areas, with different anthropogenic structural interventions on the coast such as the construction of commercial buildings and marinas, which has led to intense erosion and large imbalances in the last century. This situation also affects the city of Alicante, with the area between the port of Alicante and the Huertas Cape, one of the most depressed areas of the city, due to various actions carried out since the 70s, for anthropic example fillers for building marinas, jetties and broken in poor condition because they are made of sandstone, and a bad connection between the two parts of the city. In this work the creation of a new promenade that communicates both zones is proposed, creating new beaches eliminating anthropogenic fillings and the remains of breakwaters along the coast, the union of diverse marine area in one marina, and the insertion of an artificial reef multipurpose. With all this it is to improve the attraction of the area, and increase the mobility of the city on the coast.
Science of The Total Environment, 2017
Monitoring of the quality of bathing water in line with the European Commission bathing water dir... more Monitoring of the quality of bathing water in line with the European Commission bathing water directive (Directive 2006/7/EC) is a significant economic expense for those countries with great lengths of coastline. In this study a numerical model based on finite elements is generated whose objective is partially substituting the microbiological analysis of the quality of coastal bathing waters. According to a study of the concentration of Escherichia coli in 299 Spanish Mediterranean beaches, it was established that the most important variables that influence the concentration are: monthly sunshine hours, mean monthly precipitation, number of goat cattle heads, population density, presence of Posidonia oceanica, UV, urbanization level, type of sediment, wastewater treatment ratio, salinity, distance to the nearest discharge, and wave height perpendicular to the coast. Using these variables, a model with an absolute error of 10.6 ± 1.5 CFU/100 ml is achieved. With this model, if there are no significant changes in the beach environment and the variables remain more or less stable, the concentration of E. coli in bathing water can be determined, performing only specific microbiological analyses to verify the water quality.
Ocean Engineering, 2017
This article focuses on the optimal architecture of the neural network for determining the three ... more This article focuses on the optimal architecture of the neural network for determining the three characteristic points of the bars (starting, crest and final point). For the definition of the network, precision profiles, sedimentological and wave data were used. A total of 209 profiles taken for 22 years was used. The inputs were analysed and selected considering the variables that influenced the formation of the bars and their movement. For the selection of the optimal model different architectures were studied, generating 50 models for each of them and selecting with better results and with the smaller number of neurons in the hidden layer. To evaluate the performance of the model, various statistical errors were used (absolute error, mean magnitude of relative error and percentage relative error), with an average absolute error of 17.3 m in the distances to the coast and 0.26 m in the depths. The results were compared with equations currently employed (Table 1), which show that the errors generated by the ANN (Artificial Neural Network) are much lower (per example the MAPE committed by the proposed equation for distance to shore of the crest is 47%, while the ANN is made of 29%).
Applied Mathematical Modelling, 2016
The eigenvalues and eigenvectors of a matrix have many applications in engineering and science. F... more The eigenvalues and eigenvectors of a matrix have many applications in engineering and science. For example they are important in studying and solving structural problems, in the treatment of signal or image processing, in the study of quantum mechanics and in certain physical problems. It is therefore essential to analyze methodologies to obtain the eigenvectors and eigenvalues of symmetric and Hermitian matrices.In this paper the authors present a methodology for obtaining the eigenvectors and eigenvalues of a symmetric or hermitian matrix using a genetic algorithm. Unlike other methodologies, the process is centred in searching the eigenvectors and calculating the eigenvalues afterwards. In the search of the eigenvectors a genetic-based algorithm is used. Genetic algorithms are indicated when the search space is extended, unknown or with an intricate geometry. Also, the target vector space can be either real or complex, allowing in this way a wider field of application for the proposed method. The algorithm is tested comparing the results with those obtained by other methods or with the values previously known. So, seven applications are included: a real symmetric matrix corresponding to a vibrating system, a complex hermitian matrix and an important application of the diagonalization problem (Coope matrix) corresponding to quantum mechanics examples, a physical problem in which data are analysed to reduce the number of variables, a comparison with the power method and the studies of a degenerate and an ill-conditioned matrix.
WIT Transactions on Ecology and the Environment, 2009
When studying and modelling Complex Systems where there can be a considerable number of variables... more When studying and modelling Complex Systems where there can be a considerable number of variables and relations, it is very important to obtain methodologies that help us to model natural phenomena, these being phenomena present in the physical world and real life. Hypothetically, if we consider a relation defined by a set of variables, () 1 2 , ,......, n y f x x x = , symbolic and numerical methodologies can be obtained. This article presents a model of n-dimensional finite elements that provides the basis for defining a numerical methodology for studying and modelling complex systems. The use of n-dimensional elements then allows us to represent the relation using the values of the same for a finite number of points, this being carried out by resolving an optimization problem. To obtain the geometric model it was necessary to use the correct data structure design and programming to allow effective management of the acquisition and storage of the elements, the nodes considered for each, as well as the functions and procedures needed to approach the problem of optimisation. Finally, we applied the methodology to determine the geometric model and the problem of optimization to study and model an environmental problem
Ecosystems and Sustainable Development IX, 2013
The study of natural systems implies considering new modelling methodologies that are able to pro... more The study of natural systems implies considering new modelling methodologies that are able to produce different relationships to those described with mathematical functions, which are derived from the geometry of Euclid. In this paper, the authors propose a geometric model defined by families of cubic Splines, which are the basis for a definition of a numerical methodology for the study and modelling of complex systems. Geometric models are applied in specific cases for types of relationships. One feature of the model is that the polynomials are not represented by their coefficients, because they could be highly dependent of small variations in their values, as it is analyzed in the article. The polynomials will be represented by their values at points considered in their ranges of definition, which will be called nodes. For each variable, a Spline generated from kl cubic polynomials is defined, so the first objective is the analysis of a family of Splines determined by a set of polynomials. Finally, the geometric model is determined on practical examples from experimental data and the advantages of using the new methodology, based on the identification of Splines by their values in a number of points, are discussed, compared with the usual definition from the polynomial coefficients.
Ecosytems and Sustainable Development VIII, 2011
In order to maintain a reasonable standard of living and comfort, society is dependent on using v... more In order to maintain a reasonable standard of living and comfort, society is dependent on using very high levels of energy. The challenge is to pursue sustainable development while maintaining the level of activity, transformation and progress in every productive sector. In this paper, the influence of every parameter that determinates the energy requirements of heating and cooling in residential buildings will be studied, evaluating the thermal performance of building solutions, the treatment of gaps, control and reduction of solar radiation devices, thermal bridges and ventilation, etc. In addition, there will be an analysis of the factors that optimize the performance of heating, ventilating, air conditioning and domestic hot water systems and integration of renewables in every one of them. Finally, an economic feasibility analysis of building improvements will be performed at both construction and design of facilities.
Ecosytems and Sustainable Development VII, 2009
Lotus glaber Mill, a diploid forage legume (2n=2x=12), has successfully adapted to the ecological... more Lotus glaber Mill, a diploid forage legume (2n=2x=12), has successfully adapted to the ecological characteristics of the Flooding Pampas region of the Province of Buenos Aires, Argentina. This species is highly valued, basically due to its ability to adapt to soils that do not allow other forage legumes to prosper, as well as for its high nutritional value. A genetic improvement programme of the species resulted in an induced autotetraploid population known as "Leonel" (2n=4x= 24). Generally speaking, induced autotetraploid forms are larger and also more vigorous and productive than their diploid counterparts. Although fewer seeds are produced, they are heavier. This article compares certain morphological-physiological characters of the "Leonel" population and diploid cultivars. The characteristics evaluated were length (CFL), width (CFW), area (CFA), length/width ratio (L/W) of the central foliolae of the first expanded leaf from the stem apex and the vigour of the plants (V) from May to December. The following variables were also studied: days to flowering (BFP), air biomass, expressed as green material (GM) and dry material (DM), weight of a thousand seeds (WS), number of seeds per pod (NS), number of empty seeds per pod (ES) and the number of full seeds per pod (FS). Variance analysis was carried out with a completely random design using two factors, cytotype and month, for the following variables: CFL, CFW, CFA, L/W and V. For the remaining variables, variance analysis was carried out with a completely random design using one factor: cytotype. The Duncan's Test, using a level of confidence of 5%, was used to compare the mean values. In addition, analysis of the L/W ratio allowed the form of the foliolae to be determined.
Geomorphology, Apr 1, 2016
New methodology for describing the equilibrium beach profile applied to the Valencia's beaches. L... more New methodology for describing the equilibrium beach profile applied to the Valencia's beaches. L. Aragonés (a) , J.C. Serra (b) , Y. Villacampa (c) , J.M. Saval (d) , H. Tinoco (e) .
Mathematics
The problem of having ordinary differential equations (ODE) whose coefficients are unknown functi... more The problem of having ordinary differential equations (ODE) whose coefficients are unknown functions is frequent in several fields. Sometimes, it is possible to obtain samples of the values of these functions in different instants or spatial points. The present paper presents a methodology for the numeric solving of these ODE. There are approximations to the problem for specific cases of equations, especially in the case where the parameters correspond to constants. Other studies focus on the case in which the functions under consideration are linear or meet a certain condition. There are two main advantages of the proposed algorithm. First, it does not impose any condition over the data or the subsequent function from where these sample data are derived. Additionally, the methodology used in the functions modeling can control the possibility of overfitting in the function modeling. This is a crucial point in order to limit the influence of model biases in the numerical solution of ...
The Sustainable City IX, 2014
Bahía Norte, located in Alicante, is an artificial coastal area that suffers from erosion, which ... more Bahía Norte, located in Alicante, is an artificial coastal area that suffers from erosion, which disturbs the environment, the life and the economy of surrounding areas. In order to mitigate the erosion problem, a solution that provides coastal improvements and allows users to enjoy the structure is proposed. This solution develops artificial surfing reefs as a part of coastal protection management. An artificial surfing reef is not a new concept. However, it is an unknown and innovative idea in the Mediterranean Sea. Given that artificial surfing reefs are a reliable solution for the erosion suffered by the Mediterranean coastline. The project has five aims: controlling the sand loss, providing a recreational area for surfing, improving the security of the swimmers, revitalizing a depressed area and avoiding the visual noise of common structures of coastal defense. Artificial surfing reefs shape new driven current cells that cause an accretion in the shoreline by changing the pre-existing sea currents. Moreover, in order to improve surfing conditions, they fit the shape and height of the incoming waves. This research achieves an alteration of 420 meters of shore with a maximum salient formation of 50 meters, which fits perfectly to the situation of the artificial beach closed by groins. This research has also proved the importance of developing a careful study for the emplacement for this kind of reef being the distance from the structure to the shoreline one of the most determinant factors. It suggests that placing the artificial reef at 200 meters from the coast would be an adequate option.
International Journal of Computational Methods and Experimental Measurements, 2017
In this work, numerical models were obtained for describing the segregation phenomenon in lightwe... more In this work, numerical models were obtained for describing the segregation phenomenon in lightweight aggregate concrete. To that end, a numerical methodology based on the generation of geometric models of finite elements has been applied, selecting those that describe better this phenomenon. The use of lightweight aggregate concretes (LWC) allows greater design flexibility and substantial cost savings. It is also well known that it contributes to a positive impact on the energy consumption of a building due to the high-thermal resistance values. However, lightweight concretes are susceptible to present aggregate segregation due to density differences between its components during concrete vibration. Segregation in concrete may strongly affect the concrete global properties. This fact justifies the needs for the identification and quantification of this phenomenon, in order to estimate the concrete segregation experimentally, a LWC was mixed in laboratory conditions. Controlled segregation was caused applying different times of internal vibration in a cylinder specimen. The specimens were horizontally sectioned in order to obtain the density in each section because the segregation index can be estimated obtaining a relation by comparing the densities of the upper and lower parts. Firstly, ANOVA test was performed to determine the statistical significance (p<0.05) of the differences in the density of the different sections, differences in the aggregate type and differences in the time of concrete vibration. Results show that there is a significant difference of each section and there is no significant difference of each lightweight aggregate used to mix the concrete in spite of their different density. In order to model the segregation in the LWC, at first, linear models were considered and rejected because for not explaining the phenomenon. However, the application of numerical models shows good results to describe the phenomenon of segregation in LWC.
Computational Methods and Experimental Measurements XIX, 2019
The steel to concrete bond mechanism is critical to address the behaviour of reinforced concrete ... more The steel to concrete bond mechanism is critical to address the behaviour of reinforced concrete structural members. Although this mechanism can be compromised during a fire, it may be one of the least researched phenomena in concrete technology and is not addressed in the design codes and standards. In this work, we present a thorough review of the experimental data available on this topic, focusing on fibre-reinforced concrete. The data allow us to study the evolution of the bond strength as a function of three variables: the exposure temperature, the type of fibre and the volume fraction. A linear multiple regression is initially carried out, followed by a series of non-linear numerical models. These models are built using a methodology based on the finite element method combined with the formulation of the Galerkin method. The numerical models have been developed for different degrees of complexity. The error measurements obtained with the linear regression and the numerical models are compared in order to present a prediction model. The selected model is then validated for different values of the independent variables. This process supports the discussion of the influence that the independent variables have in the evolution of the bond strength between steel reinforcement and fibrereinforced concretes exposed to high temperatures.
In the hills of Azul (Province of Buenos Aires, Argentina) populations of Acacia nzelanoxylon R.B... more In the hills of Azul (Province of Buenos Aires, Argentina) populations of Acacia nzelanoxylon R.Brown are spread spontaneously. Although diffusion mechanisms are unknown, it is supposed that these populations derive from exotic cultivated trees introduced in the gardens and ornamental woods in the first decades of X X '~
Sustainability, 2021
One of the main problems faced in coastal management is the loss or destruction of beaches due to... more One of the main problems faced in coastal management is the loss or destruction of beaches due to erosion. A considerable diversity of factors is involved in coastal erosion, which makes it a complex system to study. The quality of the material that constitutes the beach, as well as the choice of appropriate materials for its nourishment are two of the main ones. Therefore, to make future nourishment projects more sustainable and durable, this work proposes a sediment quality classification based on the physical properties and wear process obtained through laboratory tests. The study of these variables, using principal component analysis, discriminant analysis and ANOVA, has divided the quality of 70 samples into three main groups. A Sediment Quality Classification Index (SQCI) is proposed, which categorizes the quality of the material into poor, regular or good, providing the coastal engineer with a simple tool to ensure more sustainable beach nourishments.
Marine Georesources & Geotechnology, 2020
Science of The Total Environment, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Marine Georesources & Geotechnology, 2017
The paper describes the training, validation, testing and application of models of artificial neu... more The paper describes the training, validation, testing and application of models of artificial neural networks (ANN) for computing the cross-shore beach profile of the sand beaches of the province of Valencia (Spain). Sixty ANN models were generated by modifying both the input variables as the number of neurons in the hidden layer. The input variables consist of wave data
Science of The Total Environment, 2019
Coastal erosion and lack of sediment supply are a serious global problem. It is therefore necessa... more Coastal erosion and lack of sediment supply are a serious global problem. It is therefore necessary to determine the depth of closure (DoC) of a beach-key parameter in the calculation of the sand volume and the location of the beach protection elements-in a precise way. For this reason, this work generates a numerical model based on Galerkin's formulation of finite elements that provides sufficient precision for the determination of DoC with a minimum investment. Thus, after the generation of three models in which the difference was the dependent variables, the least complex has been chosen. It is composed of the variables: median sediment size, wave height and period associated with the mean flow, as well as the angle that the mean flow forms with respect to the studied profile in absolute value (α). The selected model has been compared with the most commonly used models currently in use, having an average absolute error of 0.36 m and an average MAPE of <7.5%, which represents an improvement of >70% over current models. In addition, it presents a high stability, since after the random disturbance of all the input variables (up to 5%), the model error remains stable, increasing the MAPE by a maximum of 7.4% and the average absolute error by 0.15 m. Therefore, it is possible to use the model to infer the DoC in other study areas where the values of the variables are similar to those studied here, although the selected method can be extrapolated to other parts of the world.
International Journal of Sustainable Development and Planning, 2017
Numerous studies and theories have emerged for evaluating the quality of beaches using different ... more Numerous studies and theories have emerged for evaluating the quality of beaches using different parameters. In recent years in the European region, one of the most important aspects when evaluating a beach is the quality of water and sand. The quality of water is represented by the amount of Intestinal Enterococcus and Escherichia coli. This parameter is essential and others to obtain the Blue Flag, indicating that the user of the beach can swim safely. The European Directive 2006/7/EC establishes the limits of E. coli and Enterococcus that may exist in bathing water. However, it should be noted that each ecosystem is unique, and therefore the characteristics a beach are not the same per example if you are in an inland sea, or an ocean, or equal if they are close to an urban or a natural area. In this paper, 1,392 beaches in Spain have been analysed, and it has been observed that in the Mediterranean, the beaches have a lower concentration of bacteria than other areas. In addition, it appears that the sandy beaches and urban beaches have a higher content of bacteria that natural and gravel beaches.
International Journal of Sustainable Development and Planning, 2017
Tourism development in recent decades has involved a large urban development in coastal areas, wi... more Tourism development in recent decades has involved a large urban development in coastal areas, with different anthropogenic structural interventions on the coast such as the construction of commercial buildings and marinas, which has led to intense erosion and large imbalances in the last century. This situation also affects the city of Alicante, with the area between the port of Alicante and the Huertas Cape, one of the most depressed areas of the city, due to various actions carried out since the 70s, for anthropic example fillers for building marinas, jetties and broken in poor condition because they are made of sandstone, and a bad connection between the two parts of the city. In this work the creation of a new promenade that communicates both zones is proposed, creating new beaches eliminating anthropogenic fillings and the remains of breakwaters along the coast, the union of diverse marine area in one marina, and the insertion of an artificial reef multipurpose. With all this it is to improve the attraction of the area, and increase the mobility of the city on the coast.
Science of The Total Environment, 2017
Monitoring of the quality of bathing water in line with the European Commission bathing water dir... more Monitoring of the quality of bathing water in line with the European Commission bathing water directive (Directive 2006/7/EC) is a significant economic expense for those countries with great lengths of coastline. In this study a numerical model based on finite elements is generated whose objective is partially substituting the microbiological analysis of the quality of coastal bathing waters. According to a study of the concentration of Escherichia coli in 299 Spanish Mediterranean beaches, it was established that the most important variables that influence the concentration are: monthly sunshine hours, mean monthly precipitation, number of goat cattle heads, population density, presence of Posidonia oceanica, UV, urbanization level, type of sediment, wastewater treatment ratio, salinity, distance to the nearest discharge, and wave height perpendicular to the coast. Using these variables, a model with an absolute error of 10.6 ± 1.5 CFU/100 ml is achieved. With this model, if there are no significant changes in the beach environment and the variables remain more or less stable, the concentration of E. coli in bathing water can be determined, performing only specific microbiological analyses to verify the water quality.
Ocean Engineering, 2017
This article focuses on the optimal architecture of the neural network for determining the three ... more This article focuses on the optimal architecture of the neural network for determining the three characteristic points of the bars (starting, crest and final point). For the definition of the network, precision profiles, sedimentological and wave data were used. A total of 209 profiles taken for 22 years was used. The inputs were analysed and selected considering the variables that influenced the formation of the bars and their movement. For the selection of the optimal model different architectures were studied, generating 50 models for each of them and selecting with better results and with the smaller number of neurons in the hidden layer. To evaluate the performance of the model, various statistical errors were used (absolute error, mean magnitude of relative error and percentage relative error), with an average absolute error of 17.3 m in the distances to the coast and 0.26 m in the depths. The results were compared with equations currently employed (Table 1), which show that the errors generated by the ANN (Artificial Neural Network) are much lower (per example the MAPE committed by the proposed equation for distance to shore of the crest is 47%, while the ANN is made of 29%).
Applied Mathematical Modelling, 2016
The eigenvalues and eigenvectors of a matrix have many applications in engineering and science. F... more The eigenvalues and eigenvectors of a matrix have many applications in engineering and science. For example they are important in studying and solving structural problems, in the treatment of signal or image processing, in the study of quantum mechanics and in certain physical problems. It is therefore essential to analyze methodologies to obtain the eigenvectors and eigenvalues of symmetric and Hermitian matrices.In this paper the authors present a methodology for obtaining the eigenvectors and eigenvalues of a symmetric or hermitian matrix using a genetic algorithm. Unlike other methodologies, the process is centred in searching the eigenvectors and calculating the eigenvalues afterwards. In the search of the eigenvectors a genetic-based algorithm is used. Genetic algorithms are indicated when the search space is extended, unknown or with an intricate geometry. Also, the target vector space can be either real or complex, allowing in this way a wider field of application for the proposed method. The algorithm is tested comparing the results with those obtained by other methods or with the values previously known. So, seven applications are included: a real symmetric matrix corresponding to a vibrating system, a complex hermitian matrix and an important application of the diagonalization problem (Coope matrix) corresponding to quantum mechanics examples, a physical problem in which data are analysed to reduce the number of variables, a comparison with the power method and the studies of a degenerate and an ill-conditioned matrix.
WIT Transactions on Ecology and the Environment, 2009
When studying and modelling Complex Systems where there can be a considerable number of variables... more When studying and modelling Complex Systems where there can be a considerable number of variables and relations, it is very important to obtain methodologies that help us to model natural phenomena, these being phenomena present in the physical world and real life. Hypothetically, if we consider a relation defined by a set of variables, () 1 2 , ,......, n y f x x x = , symbolic and numerical methodologies can be obtained. This article presents a model of n-dimensional finite elements that provides the basis for defining a numerical methodology for studying and modelling complex systems. The use of n-dimensional elements then allows us to represent the relation using the values of the same for a finite number of points, this being carried out by resolving an optimization problem. To obtain the geometric model it was necessary to use the correct data structure design and programming to allow effective management of the acquisition and storage of the elements, the nodes considered for each, as well as the functions and procedures needed to approach the problem of optimisation. Finally, we applied the methodology to determine the geometric model and the problem of optimization to study and model an environmental problem
Ecosystems and Sustainable Development IX, 2013
The study of natural systems implies considering new modelling methodologies that are able to pro... more The study of natural systems implies considering new modelling methodologies that are able to produce different relationships to those described with mathematical functions, which are derived from the geometry of Euclid. In this paper, the authors propose a geometric model defined by families of cubic Splines, which are the basis for a definition of a numerical methodology for the study and modelling of complex systems. Geometric models are applied in specific cases for types of relationships. One feature of the model is that the polynomials are not represented by their coefficients, because they could be highly dependent of small variations in their values, as it is analyzed in the article. The polynomials will be represented by their values at points considered in their ranges of definition, which will be called nodes. For each variable, a Spline generated from kl cubic polynomials is defined, so the first objective is the analysis of a family of Splines determined by a set of polynomials. Finally, the geometric model is determined on practical examples from experimental data and the advantages of using the new methodology, based on the identification of Splines by their values in a number of points, are discussed, compared with the usual definition from the polynomial coefficients.
Ecosytems and Sustainable Development VIII, 2011
In order to maintain a reasonable standard of living and comfort, society is dependent on using v... more In order to maintain a reasonable standard of living and comfort, society is dependent on using very high levels of energy. The challenge is to pursue sustainable development while maintaining the level of activity, transformation and progress in every productive sector. In this paper, the influence of every parameter that determinates the energy requirements of heating and cooling in residential buildings will be studied, evaluating the thermal performance of building solutions, the treatment of gaps, control and reduction of solar radiation devices, thermal bridges and ventilation, etc. In addition, there will be an analysis of the factors that optimize the performance of heating, ventilating, air conditioning and domestic hot water systems and integration of renewables in every one of them. Finally, an economic feasibility analysis of building improvements will be performed at both construction and design of facilities.
Ecosytems and Sustainable Development VII, 2009
Lotus glaber Mill, a diploid forage legume (2n=2x=12), has successfully adapted to the ecological... more Lotus glaber Mill, a diploid forage legume (2n=2x=12), has successfully adapted to the ecological characteristics of the Flooding Pampas region of the Province of Buenos Aires, Argentina. This species is highly valued, basically due to its ability to adapt to soils that do not allow other forage legumes to prosper, as well as for its high nutritional value. A genetic improvement programme of the species resulted in an induced autotetraploid population known as "Leonel" (2n=4x= 24). Generally speaking, induced autotetraploid forms are larger and also more vigorous and productive than their diploid counterparts. Although fewer seeds are produced, they are heavier. This article compares certain morphological-physiological characters of the "Leonel" population and diploid cultivars. The characteristics evaluated were length (CFL), width (CFW), area (CFA), length/width ratio (L/W) of the central foliolae of the first expanded leaf from the stem apex and the vigour of the plants (V) from May to December. The following variables were also studied: days to flowering (BFP), air biomass, expressed as green material (GM) and dry material (DM), weight of a thousand seeds (WS), number of seeds per pod (NS), number of empty seeds per pod (ES) and the number of full seeds per pod (FS). Variance analysis was carried out with a completely random design using two factors, cytotype and month, for the following variables: CFL, CFW, CFA, L/W and V. For the remaining variables, variance analysis was carried out with a completely random design using one factor: cytotype. The Duncan's Test, using a level of confidence of 5%, was used to compare the mean values. In addition, analysis of the L/W ratio allowed the form of the foliolae to be determined.