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Multi-Media applications are amongst the most demanding services, requiring high amounts of network capacity and computational resources for synchronous audio-visual streaming with high quality. Gaming streaming is one of the most demanding of these media applications. Recent technological advances in the 5G domain, precisely Network Function Virtualization (NFV) and Multi-access Edge Computing (MEC), unlock media industries’ potential by offering high-quality media services through dynamic and efficient resource allocation with low latency. This work presents a multi-site gaming streaming use case implemented over an end-to-end 5G-enabled platform provided by the EU H2020 5G-PPP 5G EVE project. Furthermore, we present the executed use case experiment scenarios to validate the use case performance following a set of defined Quality of Experience(QoE)-related Key Performance Indicators (KPIs). In particular, this paper discusses the design workflow and orchestration of the multi-site gaming streaming use case across two 5G EVE sites (i.e., Spain and Greece), providing a detailed description of the network function applications and resources utilized for the use case. Subsequently, leveraging the 5G EVE monitoring platform, this paper elaborates on the executed experiment scenarios that provide the defined KPI metrics data. Finally, this paper presents, discusses, and analyzes the obtained KPI metrics data results and provides recommendations on future works for these kinds of use cases. [ABSTRACT FROM AUTHOR]

In this paper, we design an Anomaly Detection (AD) framework for mobile data traffic, capable of identifying different types of anomalous events generated by flash crowds in metropolitan areas. We state the problem using a semi-supervised approach and exploit the great performance of different Recurrent Neural Network (RNN) models to learn the temporal context of input sequences. Our proposal processes real traffic traces from the unencrypted LTE Physical Downlink Control Channel (PDCCH) of an operative network, gathered during an extensive measurement campaign in two major cities in Spain. The AD framework is designed to perform: i) a-posteriori analysis to understand users’ behavior and urban environment variations; ii) real-time analysis to automatically and on-the-fly alert urban anomalies; and iii) estimation of the duration of the periods identified as anomalous. Numerical results show the higher performance of our AD framework compared to classic AD algorithms and confirm that the proposed framework predicts anomalous behaviours with high accuracy and regardless of their cause. [ABSTRACT FROM AUTHOR]

Banks are the backbone of the financial sector and catalysts in the economic development of any country. Current changes in their global business ecosystem make knowledge of about the fund-supplying and fund-demanding parties of the society a key resource for the fulfillment of banks’ investment and saving functions. This paper addresses the relationship between the performance and a learning culture that is supported by knowledge processes within the organization. Given the relevance of this subject for organizations from most knowledge-intensive domains, this research has focused on the Spanish banking sector. Using a structural equation model, feedback received from 215 employees from 142 individual branches from a major banking institution in Spain is studied. The results of the data analysis show that in addition to maximizing on what is already known about the customer base, employees’ learning about the potential new stakeholders and also about the internal strategies, tools, and techniques is directly related to the bank's performance, which, in turn, influences the economic recovery and socio-economic development. Results support that an active pursuit of learning within the context of the organization is required for banks to remain competitive in the dynamic, global business ecosystem, where international, national, and local banking sectors operate. [ABSTRACT FROM AUTHOR]

This paper addressesthe problem of real-time state estimation in European-type four-wire low-voltage distribution networks with advanced metering infrastructure based on power line communication (PLC). The main drawback of this type of infrastructure is its high latency and a sequential data sampling process. Both factors make it difficult to obtain instantaneous values from the smart meters in a timely and adequate manner to estimate the real-time state of the system. This problem may be solved in the future with the deployment of metering systems based on other technologies such as 5G. However, PLC technology prevails in many countries, and is not likely to be replaced in the medium term. In the meantime, a solution is needed to provide acceptable real-time state estimates in low voltage networks, not to hinder the active management of these assets in the context of smart grids. In this work, a solution is proposed that allows estimating the state of the low voltage network with a reasonable accuracy considering the low quality of the measurements provided by the deployed infrastructure. The system is validated using a portion of a real pilot network located in the north of Spain fed by a transformer station with seven feeders. [ABSTRACT FROM AUTHOR]

The large penetration of renewable energy resources is demanding additional flexibility for the operation of power systems. In this sense, real world applications are proving that wind power units are able to provide part of the required flexibility. Therefore, these new sources of flexibility need to be considered by power system planners in order to make appropriate generation capacity expansion decisions. This paper proposes a generation and storage capacity expansion formulation considering that wind power units are able to participate in the reserve provision service. The proposed model is a stochastic linear program that is solved using a commercial solver. A case study based on the isolated power system of Lanzarote and Fuerteventura in Spain is solved to quantify the impact of considering the reserve provision of wind power in capacity investment decisions. [ABSTRACT FROM AUTHOR]

5G is a key tool for the cloud-based wireless production of audio-visual contents. By providing higher throughput and lower latency than previous mobile network technologies, as well as flexible allocation of network resources, it enables that some content production pipelines, which are currently implemented using wired connectivity, are provided on top of a 5G network. This brings down production costs, reduces environmental impact and increases operational efficiency. In particular, live immersive production services, such as free-viewpoint video (FVV), can be provided in a much more efficient way. In this paper, we address the challenge of producing and streaming FVV services in real time through 5G networks. We have adapted a state-of-the-art FVV system to integrate it within a 5G architecture, using three key technological enablers: mmWave radio access network to support the uplink traffic requirements from FVV cameras, multi-access edge computing to run video processing algorithms with minimum latency, and end-to-end slicing to guarantee a sufficient quality of service (QoS) within the production pipeline. We have built a field trial over the production network of a telecommunication operator, including a mmWave pilot deployment, edge cloud processing, and remote content production, involving three different locations across Spain. We have measured the key performance indicators at the relevant parts of our trial deployment, showing that, with existing 5G technology, it is possible to achieve live FVV production, although with some limitations. We have also analyzed such limitations, obtaining some insights on how the next generation of 5G networks can overcome them to achieve higher quality of experience (QoE). [ABSTRACT FROM AUTHOR]

Non-technical losses (NTL) in electricity utilities are responsible for major revenue losses. In this paper, we propose a novel end-to-end solution to self-learn the features for detecting anomalies and frauds in smart meters using a hybrid deep neural network. The network is fed with simple raw data, removing the need of handcrafted feature engineering. The proposed architecture consists of a long short-term memory network and a multi-layer perceptrons network. The first network analyses the raw daily energy consumption history whilst the second one integrates non-sequential data such as its contracted power or geographical information. The results show that the hybrid neural network significantly outperforms state-of-the-art classifiers as well as previous deep learning models used in NTL detection. The model has been trained and tested with real smart meter data of Endesa, the largest electricity utility in Spain. [ABSTRACT FROM AUTHOR]

The recently approved regulation about self-consumption in Spain will dramatically change the level of penetration of photovoltaic distributed generation combined with storage devices at residential level in short term. In this paper, we will study the impact of the massive installation of such technologies under the constraints imposed by the new regulation, over the terminal distribution network. As it will be demonstrated, this impact will be drastic in terms of energy demand, voltage profile, and load curves. [ABSTRACT FROM AUTHOR]

The five papers in this special section are extended versions of papers presented at the 5th International Conference on Mechatronics (ICM 2009), held in Malaga, Spain in April 2009. [ABSTRACT FROM AUTHOR]

This paper describes the configuration, modeling, and control of a fuel cell (FC)-battery-powered hybrid system for the Metro Centro tramway in Seville, Spain. The proposed hybrid system presents a polymer electrolyte membrane FC as the primary energy source and a nickel-metal hydride cell battery as the secondary energy source, which supplements the output of the FC during tramway acceleration or whenever else needed and cruise and for energy recovery during braking. The tramway presents a traction system which is composed of four traction induction motor drives. The hybrid system also supplies the power for the auxiliary services. The power conditioning system is composed of two converters: 1) a boost-type unidirectional dc/dc converter for the FC and 2) a boost-type bidirectional dc/dc converter for the battery. The energy management system (EMS) of the hybrid tramway determines the reference signals for the electric motor drives, FC, and power converters in order to regulate accurately the power from the two electrical sources. EMS also determines the reference signal for energy dissipation in braking chopper when required during regenerative braking. In this paper, the proposed hybrid system is evaluated for the real driving cycle of the tramway. The results demonstrate the hybrid system capability to meet appropriate driving cycle. [ABSTRACT FROM PUBLISHER]

This paper focuses on the validation of the empirically corrected total ozone column (TOC) data provided by the Earth Probe Total Ozone Mapping Spectrometer (EP-TOMS) using ground-based measurements recorded by a well-calibrated Brewer spectroradiometer located at El Arenosillo (Spain). In addition, satellite TOC observations derived from the OzoneMonitoring Instrument (OMI) with the TOMS algorithm are also used in this paper. The agreement between EP-TOMS TOC data and Brewer measurements is excellent (R² ~ 0.92) even for the period 2000-2005 when a higher EP-TOMS instrument degradation occurred. Despite its low magnitude, the EP-TOMS-Brewer relative differences depend on the solar zenith angle (SZA), showing a clear seasonal cycle with amplitude between ±2% and ±4%. Conversely, OMI-Brewer relative differences show a constant negative value around -1% with no significant dependence on SZA. No significant dependence on the ground-based to satellitebased differences with respect to the EP-TOMS scene or to the OMI crosstrack position is observed for either satellite retrieval algorithm. Finally, TOC, estimated by the two satellite instruments, have also been compared, showing a good agreement (R² ~ 0.88). Overall, we conclude that the empirical correction of the EP-TOMS data record provides a reprocessed set of high quality. However, EP-TOMS data after year 2000 should not be used in calculations of global-ozone trending due to remaining errors in the data set and because it is no longer an independent data set. [ABSTRACT FROM AUTHOR]

This paper describes and analyzes the Spanish AGC system. The differences with respect to a standard hierarchical structure are explained. A simple model useful for simulation is proposed. Using this model, the performance of the system and the influence of several parameters in system response is evaluated. The paper also suggests some changes in the configuration and parameter settings of the system to improve its performance. [ABSTRACT FROM AUTHOR]

The penetration level of wind energy is continuously growing, and it is especially relevant in European countries such as Denmark, Germany, and Spain. For this reason, grid codes in different countries have been recently revised, or are now under revision in order to integrate this energy in the network taking into account the security of supply. This paper is related to reactive compensation, which is one aspect usually included in these codes. On the other hand, a great number of installed wind parks are formed by fixed speed wind turbines equipped with induction generators. The typical scheme for reactive compensation in this kind of wind parks is based on capacitor banks locally controlled in each machine. This configuration makes very difficult to follow the requirements of the new grid codes. To overcome this problem, a configuration with a central controller that coordinates the actuation over all the capacitor steps in the wind park is proposed in this paper. A central controller algorithm that is based on a dynamic programming is presented and evaluated by means of simulation. At this time, the proposed scheme has been installed at the Sotavento Experimental Wind Park (Spain) and it is currently being tested. [ABSTRACT FROM AUTHOR]

This two-part paper surveys the frequency and voltage control ancillary services in power systems from various parts of the world. In this first part, the nomenclature used to describe active power reserves across 11 systems is first reviewed in order to facilitate the comparison of frequency control ancillary services. The essential technical features of frequency and voltage control ancillary services are then described. Finally, the technical requirements adopted in eight jurisdictions (North America, continental Europe, Germany, France, Spain, the Netherlands, Belgium, and Great Britain) are compared. The companion paper surveys the economic features of these ancillary services. [ABSTRACT FROM AUTHOR]

In this paper, an introduction to the main design features of a computer-aided educational package addressed to students of the final years of Electronic and Computer Engineering is presented. The software includes interrelated tutorial, computer simulations, and test questions in which graphical outputs, hypertexts, and animations are widely used. The package is devoted to the simulation study of electrooptic and acoustooptic theory and devices. It provides instant numerical evaluation and a graphical display of different studies. The software presented in this paper has all the following features: an integrative character, self-evaluation tests, a personalized and active learning process, adaptability to teacher's aims, versatility as a teaching tool, multimedia resources, and simplicity. This study has been completed with final-year students at the Superior Polytechnic School of Cordoba, Spain, with highly favorable results when compared with students who did not use the software. [ABSTRACT FROM AUTHOR]

This paper presents some experimental results on the application of signal processing techniques to underwater seismic signals. The novelty of this paper stems from the fact that it is the first paper, to the best of the authors' knowledge, dealing with a comprehensive processing of signals obtained from active refraction seismology. In particular, this paper has adapted known signal processing techniques to problems such as time of arrival detection (TOA), compression, and representation through conventional images (hodocrones) used in underwater seismology. This work is part of a wider project aimed at the design of a small ocean bottom seismometer (OBS) undertaken by several research and development groups in Spain. This sophisticated easy to handle equipment allows recording useful active and passive seismicity information. [ABSTRACT FROM AUTHOR]

This paper presents an approach to determine the optimal daily generation scheduling based on the Spanish electricity market rules. The Spanish power system considers the pool-based daily market and the technical constraints resolution as two different and consecutive processes. After the daily market has been cleared, a centralized constraints resolution process is applied to this initial scheduling through the redispatch of previously matched energy. In this paper, an algorithm based on Benders decomposition, arranged in three levels, is proposed to solve the technical constraints solution process in order to define a preventive secure dispatch. The constraints resolution process includes a full ac network and security model. This method determines the active power committed to each generating unit so as to minimize the energy redispatch cost subject to dispatch, network, and security constraints. The solution also provides the reactive power output of the generating units, the value of the transformers taps, and the committed voltage control devices. The model has been tested in an actual example of the Spanish power system. Some relevant results are reported. [ABSTRACT FROM AUTHOR]

In this paper, a probabilistic methodology for estimating the energy costs in the market for wind generators associated with wind prediction errors is proposed. Generators must buy or sell energy production deviations due to prediction errors when they bid in day-ahead or hour-ahead energy markets. The prediction error is modeled through a probability density function that represents the accuracy of the prediction model. Production hourly energy deviations and their associated trading costs are then calculated. Three study cases based on real wind power installations in Spain are analyzed. The three study cases show that the error prediction costs can reach as much as 10% of the total generator energy incomes. [ABSTRACT FROM AUTHOR]

This paper describes the undergraduate radar course taught at the Escola Universitària Politècnica del Baix Llobregat (EUPBL) of the Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. At present, the EUPBL offers a three-year degree in Technical Telecommunications Engineering. This paper briefly describes the EUPBL, the organization of the degree program, the structure of the radar course, the evaluation methods, and two practical exercises on a sonar demonstrator and a global positioning system kit. [ABSTRACT FROM AUTHOR]

Tunnels represent strong multipath environments for communications, where wireless propagation differs from regular indoor or outdoor scenarios. Moreover, with an adequate operating frequency choice, a tunnel behaves as an oversized waveguide, extending the communication range but affecting the signal with strong fadings. These fadings have been closely studied in the literature in the longitudinal dimension (tunnel length). Nevertheless, they also occur in the cross section, where they have only been analyzed statistically and on a small scale. In this paper, we present the results from an extensive measuring campaign carried out at the Somport tunnel, in Spain. We have adopted the modal theory approach to analyze the large-scale fadings (also known as slow fadings) in the longitudinal, transversal, and vertical dimensions. More specifically, the modes’ geometry allowed for the adequate placement of transmitters to create different periodic fading structures and to virtually divide the tunnel cross section into sectors, where the fadings presented a phase shift of 180°. This study enabled the development of large-scale spatial diversity schemes and navigation techniques to improve communication and localization inside these scenarios. [ABSTRACT FROM AUTHOR]

Minimizing energy consumption in buildings is one of the priorities of the European Union energy strategy. The European legislation has defined a legal framework to determine the energy qualification of a building that is used by each of the member states to define its own energy qualification procedure. This paper presents a methodology to evaluate the effect of climate conditions in the energy qualification procedure. It evaluates the effectiveness of the qualification in representing the yearly energy demand and \CO2 emissions. Moreover, it determines the effects of improvements in different parameters of the procedure (e.g., the construction materials of the enclosure, thermal installations, etc.) in order to improve qualifications. It has been applied to the Spanish legislation using a series of simulations of a typical domestic building, with climatic data from different zones of the Spanish territory. The most significant results are the similarity in the energy certification values obtained in all scenarios and the lack of concordance between the energy rating scale, energy consumption, and \CO2 emissions. [ABSTRACT FROM PUBLISHER]

This paper shows the results of a survey performed in Spain on the different functionalities of e-learning platforms. This survey was filled in by a group of teachers, experts in engineering education from across Spain, within the scope of the Spanish Chapter of the IEEE Education Society. This paper presents their opinions on several aspects of e-learning functionalities, such as knowledge levels, levels of use, and usefulness, as well as describing the most commonly used platforms. One of the objectives of this work is to create a debate in the international community about the use of e-learning platforms and their main functionalities, the most frequently used standards, the implications for and the levels of support by institutions in their use of e-learning platforms, and in general, their advantages and disadvantages. [ABSTRACT FROM AUTHOR]

This paper describes the application of sliced inverse regression to model the electrochemical process of aluminum smelter plants. Real data measurements obtained during several years in a Spanish industrial environment are used to illustrate the main dependencies between parameters. Nonlinear relations between the output variables and relevant linear combinations of input variables are deduced. An exploratory statistical analysis is also presented, checking for correlations and possible linear dependencies. [ABSTRACT FROM AUTHOR]

A novel hybrid approach, combining wavelet transform, particle swarm optimization, and adaptive-network-based fuzzy inference system, is proposed in this paper for short-term electricity prices forecasting in a competitive market. Results from a case study based on the electricity market of mainland Spain are presented. A thorough comparison is carried out, taking into account the results of previous publications. Finally, conclusions are duly drawn. [ABSTRACT FROM AUTHOR]

This paper proposes a fault diagnosis method using a timed discrete-event approach based on interval observers that improves the integration of fault detection and isolation tasks. The interface between fault detection and fault isolation considers the activation degree and the occurrence time instant of the diagnostic signals using a combination of several theoretical fault signature matrices that store the knowledge of the relationship between diagnostic signals and faults. The fault isolation module is implemented using a timed discrete-event approach that recognizes the occurrence of a fault by identifying a unique sequence of observable events (fault signals). The states and transitions that characterize such a system can directly be inferred from the relation between fault signals and faults. The proposed fault diagnosis approach has been motivated by the problem of detecting and isolating faults of the Barcelona's urban sewer system limnimeters (level meter sensors). The results obtained in this case study illustrate the benefits of using the proposed approach in comparison with the standard fault detection and isolation approach. [ABSTRACT FROM AUTHOR]

The level of secondary reserve needed in a power system is traditionally settled by system operators according to engineering criteria. This paper proposes a novel methodology to determine the optimum level of secondary reserve based on both engineering and economic criteria. Within the proposed approach a price elastic-quantity demand curve for the secondary reserve is built. This approach assumes that the provision of secondary reserve is made under a competitive market. In this market, the supply curve that collects the bids from generators providing secondary reserve is matched with the calculated elastic demand cost curve. The cross of the supply and demand curves determines the optimal level of secondary reserve and the price for provision of the service. The developed approach is illustrated with a case study based on the current day-ahead secondary reserve market in Spain. [ABSTRACT FROM AUTHOR]

Problem-based learning (PBL) has proved to be a highly successful pedagogical model in many fields, although it is not that common in computer engineering. PBL goes beyond the typical teaching methodology by promoting student interaction. This paper presents a PBL trial applied to a course in a computer engineering degree at the University of Seville, Spain. To promote the reusability and interoperability of the PBL trial, a design-driven approach was used, based on the Internet protocol Multimedia Subsystems (IMS) Learning Design (LD) standard. This paper presents the outcomes of using this method to innovate teaching practices in a blended learning environment. Design and implementation results, as well as users' opinions, are presented and analyzed. [ABSTRACT FROM AUTHOR]

In a competitive electricity market, an accurate forecasting of energy prices is an important activity for all the market participants either for developing bidding strategies or for making investment decisions. An adaptive wavelet neural network (AWNN) is proposed in this paper for short-term price forecasting (STPF) in the electricity markets. A commonly used Mexican hat wavelet has been chosen as the activation function for hidden-layer neurons of feed-forward neural network (FFNN). To demonstrate the effectiveness of the proposed approach, day-ahead prediction of market clearing price (MCP) of Spain market, which is a duopoly market with a dominant player, and locational marginal price (LMP) forecasting in PJM electricity market, are considered. The forecasted results clearly show that AWNN has good prediction properties compared to other forecasting techniques, such as wavelet-ARIMA, multi-layer perceptron (MLP) and radial basis function (RBF) neural networks as well as recently proposed fuzzy neural network (FNN). [ABSTRACT FROM AUTHOR]

This paper introduces and evaluates BioLab, a tool for teaching biosignal processing. BioLab has been used in the biomedical engineering module that is given in the second semester of the fifth year of the electronic engineering degree at the University of Valencia, Spain. This module and its correspondent curricular pathway are also reviewed. BioLab allows the results obtained with digital processing techniques to be shown interactively in the theory classes, and it also provides support in laboratory sessions. The graphic interface of BioLab simplifies its learning and use and provides access to processing and visualization functions by means of menus. The tool is based on Matlab since the students have had previous experience in this environment. BioLab also supports diverse formats of data files, which facilitate access to real records and their conversion to usable formats. The modular structure of BioLab allows it to be easily extended to other educational materials that are related to signal processing and to research applications. An evaluation of BioLab has revealed that students found it useful for understanding the general concepts of digital processing and biosignal processing in particular. The students also found BioLab very easy to learn and use. [ABSTRACT FROM AUTHOR]

The aim of the Spanish voltage control ancillary ser- vice is the minimization of the transmission losses while keeping the system away from voltage instability. The latter target can be achieved maintaining an adequate voltage profile in normal operating condition and assuring that generators exhibit enough reactive margins that guarantee that the system voltages will remain under acceptable values in case of contingencies. The service has been designed in Spain to be partially mandatory and partially subject to payment based on market-driven rules and performance evaluation. In the annual time scope, the optional reactive offers submitted by the service suppliers are selected analyzing a number of forecasted scenarios. This paper explains the implementation of the Spanish voltage control ancillary service (VCAS) that is provided by generators in the annual time scope. For this purpose, a mixed-integer linear programming optimal power flow (OPF) is used. Reactive bids of generators are modeled within each scenario by modifying the reactive limits of the generators. The use of the proposed OPF in the assignment of the voltage control ancillary service is explained and illustrated using actual scenarios of the Spanish power system. [ABSTRACT FROM AUTHOR]

In this paper, an efficient method based on a new fuzzy neural network is proposed for short-term price fore- casting of electricity markets. This fuzzy neural network has inter-layer and feed-forward architecture with a new hypercubic training mechanism. The proposed method predicts hourly market-clearing prices for the day-ahead electricity markets. By combination of fuzzy logic and an efficient learning algorithm, an appropriate model for the nonstationary behavior and outliers of the price series is presented. The proposed method is examined on the Spanish electricity market. It is shown that the method can provide more accurate results than the other price forecasting techniques, such as ARIMA time series, wavelet-ARIMA, MLP, and RBF neural networks. [ABSTRACT FROM AUTHOR]

The solution of power system constraints is an important issue that has to be addressed to achieve a fair operation of a competitive electricity market. In the Spanish electricity market, the System Operator (SO) is in charge of determining the technical feasibility of the generation dispatch provided by the Market Operator (MO). An optimal solution method of power system constraints in the Spanish market must take into account the connection of off-line units to solve both branch overloads and voltage constraints, the adjustment of voltage control resources, the solution of the postulated n-I and n-2 contingencies with a preventive criteria and the coupling of the solution in the 24 hourly scenarios due to the start-up cost of nonconnected units. This paper details the management of power system constraints in the Spanish market, and contains a comprehensive review of solution methods of power system constraints. In addition, the paper proposes a novel approach to solve Spanish power system constraints that overcomes the limitations of existing methods, by decoupling the solution of branch overloads and voltage constraints. [ABSTRACT FROM AUTHOR]

This paper presents a field measurement campaign developed to study the influence of the special features of a Single Frequency Network (SFN) reception in the C/N thresholds applicable to portable DTV reception. The measurements presented here were performed inside coverage areas of the nation wide SFN which broadcasts DTV (COFDM 8 K mode) services in Spain. The aim of this paper is to present some network planning reference values for portable reception in urban environments where both multipath and multiple transmitter reception have to be taken into account to ensure a good quality of service. [ABSTRACT FROM AUTHOR]

This paper presents the measurement results obtained in an extensive field test campaign developed in two large cities of Spain (Madrid and Bilbao) with the aim of characterizing the portable outdoor reception of digital terrestrial television (COFDM) and continue the studies carried out by the authors during the past years [1], [2]. [ABSTRACT FROM AUTHOR]

Information about several topics discussed at the 2007 IEEE International Symposium on Intelligent Signal Processing held at Alcalá de Henares in Madrid, Spain in October 3-5 is presented. Topics include mobile robot applications and their interaction with the environment. It also discussed intelligent image analysis and intelligent sensor processing.

The increasing installed wind power capacity has caused wind power generation to become a significant percentage of the entire electric power generation. As a consequence, the power system operators have included wind power plants regulation to improve the control of the overall power system, both in steady-state and transient operation. Therefore, wind power systems are required to verify the grid connection requirements stated by the power system operators. In presence of grid voltage dips, the low voltage ride-through (LVRT) requirement compliance produces a mismatch between the generated active power and the active power delivered to the grid. The conventional solution assumes that the active power surplus is dissipated in a dc-link resistor. In this paper, a control scheme for the back-to-back neutral-point-clamped converter is proposed. Under grid voltage dip, the controllers for generator-side and grid-side converters work concurrently to meet the LVRT requirement by storing the active power surplus in the turbine-generator mechanical system inertia while keeping constant the dc-link voltage. Simulation and experimental results verify the proposed control scheme. [ABSTRACT FROM PUBLISHER]

Building density information plays an essential role in the design, planning, and management of modern cities. This paper presents an automated approach to urban analysis using airborne laser scanner data to derive geometric information (heights, areas, and volumes) and urban density attributes (building coverage ratio and floor area ratio) of buildings, land lots, and urban units. In particular, four urban units are analyzed in the city of Avila, Spain, which has experienced considerable growth in recent years. The urban map and building density results are used to validate the utility of the automated method with respect to cadastral data and applicable regulations (Urban Land Law, 2008, and Urban Regulation General Plan, 2005). The algorithms for these operations are implemented in the Spatial Analyst ArcGIS extension module. [ABSTRACT FROM PUBLISHER]

Although the literature on environmental sustainability is rapidly increasing, many studies suggest that this problem needs to be dealt with by considering a broader perspective, i.e., supply chains. In this paper, we put forward the idea that different practices for greening suppliers can be combined to shape different green supply management (GSM) strategies. More specifically, the following research questions are posed. 1) How do firms combine managerial practices to form GSM strategies? 2) What are the variables that affect this decision? 3) What are the results of the different GSM strategies? Drawing on a survey among Spanish firms, we performed a cluster analysis that identified three main GSM strategies. In the second step, we contrasted these clusters using environmental drivers, context, and performance variables. The results show that there are several approaches to “greening” the supply chain, with different results and company profiles. [ABSTRACT FROM PUBLISHER]

ac-powered contactors are extensively used in industry in applications such as automatic electrical devices, motor starters, and heaters. In this work, a practical session that allows students to model and simulate the dynamic behavior of ac-powered electromechanical contactors is presented. Simulation is carried out using a rigorous parametric model of the ac contactor that avoids simplification assumptions and is thoroughly explained. The goal of this practical is to introduce students to the topic of dynamic simulation of real devices. It covers both the transient and the steady-state response of the electromechanical system under study. The proposed methodology is flexible and not particularly time-consuming, and it allows the students easily to change the electromechanical constants of the contactor they are studying. The results of the simulations were compared with experimental data acquired by the students; a close similarity between real and simulated data was observed. The Technical University of Catalonia (UPC), Spain, has incorporated the simulation methodology proposed in this paper in a practical session of an electrical engineering course. [ABSTRACT FROM AUTHOR]

During the last few years, the number of university students choosing to follow engineering degrees has decreased dramatically in Spain. For that reason, several university departments, in collaboration with some high schools, have developed a range of activities in order to promote a higher enrollment rate, to improve the level of mathematics and physics that students have when entering university, to explode the myth of engineering degrees being difficult studies not within everyone's reach, and to rationalize the curricula of engineering degrees, coordinating all their courses and directing them toward the global objectives of the degree. In this paper, the results of an Outreach Project for Engineering Education (OPEE) comprising four successful activities developed over the last decade at the Higher Technical School of the University of Cordoba, Spain, are reported. Most important is that in the face of the significant decrease of the amount of engineering first-year students observed in Spain in general, and Cordoba in particular, enrollment in the Higher Technical School of the University of Cordoba has remained constant. [ABSTRACT FROM AUTHOR]

This paper explores both how male and female high school pupils (15-16 years old) perceive the engineering profession and their willingness to pursue a career in this area. A study was performed around a one-day outreach activity, Girls' Day, organized for the first time in Spain. During Girls' Day, students were exposed to specific activities developed for them in engineering research labs and companies, carried out by young female researchers and professionals. The study, based on two questionnaires answered before and after the activity, focuses on the differences between groups of female and male students having differing degrees of interest in studying engineering. The educational level of mothers, the presence of engineers in families, and perceived family support emerged as important factors influencing the probability of a young person's considering pursuing engineering studies. Nevertheless, the need to expose children to outreach activities at a younger age and to involve the students' families and teachers has become clear. If planned properly and thoughtfully, even a single day's experience can contribute to changing the perception of what an engineer is. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to describe and assess a new characterization and classification method of voltage dips. The proposed method allows us to classify multistage and real voltage dips when measurement errors or transients are present in the recorded data. Different real voltage dips are used to assess this method, comparing the results with previous approaches. For visualization purposes, a voltage-space vector representation is introduced in order to clarify the global voltage dip evolution along the time. The classification of all the voltage dips, measured from a one-year field measurement campaign in wind farms located in the Spanish region of Castilla-La Mancha, is also presented and characterized according to the proposed method. [ABSTRACT FROM AUTHOR]

Studying fundamental Computer Architecture and Organization topics requires a significant amount of practical work if students are to acquire a good grasp of the theoretical concepts presented in classroom lectures or textbooks. The use of simulators is commonly adapted in order to reach this objective. However, as most of the available educational simulators focus on specific topics, different laboratory assignments usually require the use of different simulators. This paper presents a graphical and interactive reduced instruction set computer (RISC) processor and memory simulator that allows active learning of some theoretical concepts covered in Computer Architecture and Organization courses. The simulator can be configured to present different processor views, from a simple serial one, without caches or pipelines, to a more realistic one with caches and superscalar execution. This approach allows a set of increasingly complex code-based laboratory assignments to be developed using a single simulator, covering topics ranging from assembly language programming to the analysis (If the different kind of cache misses, pipeline hazards or branch prediction hits and misses produced during a program execution. The simulator has been included in a an automatic assessment system that helps the students to complete the assignments and helps teachers to evaluate the correctness of the students solutions in different environments, such as high-enrollment courses or distance education. Since 1996, both the simulator and the automatic assessment system have been successfully used by more than 5000 students in Computer Architecture and Organization courses at the Technical University of Madrid (UPM), Spain. [ABSTRACT FROM AUTHOR]

The research presented in this paper shows how lab work can be organized into three phases: prelab, lab, and postlab, all supported by a Web-based experimental portal and a set of tools, some of which are connected to real lab devices. Different on-line tools and simulators are used in a flexible and configurable way that can be adapted to student curricula and course needs. This scenario is based upon real cases in distance learning courses in the Industrial Engineering School at the Universidad Nacional de Educación (The Spanish Open University), Madrid, Spain. The details of the combined real and simulated activities are discussed and some conclusions and lessons learned from this work are presented. [ABSTRACT FROM AUTHOR]

The Surface Processes and Ecosystem Changes Through Response Analysis (SPECTRA) Barrax Campaigns were validation campaigns developed in the framework of the SPECTRA mission in order to verify that the geophysical data products provided by satellite imagery are consistent with the measurements made by independent means. Two campaigns took place in Barrax, Spain, during the summers of 2003 and 2004. This paper presents the results of the characterization of the atmospheric composition from solar radiation, radiosoundings, and lidar measurements. Several potentially interesting situations involving atmospheric layers with different types of aerosols and water content are discussed. The presence of a residual layer capping the mixing layer during some days of the 2003 campaign and the arrival of a dust-rich air mass from the Sahara on the last two days of the 2004 campaign provide some relevant aerosol vertical profiles to test atmospheric correction algorithms. The study of the effects of these atmospheric situations on radiative transfer calculations is required in the development and validation of advanced atmospheric correction codes for the new generation of Earth Observation Systems. [ABSTRACT FROM AUTHOR]

The article reports on the VI Spanish National Plan for Scientific R+D+I for the 2008-2011 period. The plan raises the budget to 48 billion pesos, which is double the investment for the 2003-2007 period. The structure of the new plan is based on the definition of the six instrumental lines of projects, human resources, infrastructures, institutional strengthening, internationalization of the system, and articulation. Spain hopes to promote continuous training within the area of mobility and knowledge or engineers and researchers.

The article describes the author's experience with an Internet subscription service in Madrid, Spain. Topics include: the author's frustration with having to enter so much information on the service's web page; the arrangement for purchasing time on and gaining access to the Internet; the problem of a forgotten password for the PayPal account that is complicated by the use of a different credit card on an existing account; and three lessons learned from this experience that relate to the subscriber's convenience and a website's design and usability.

This is the fourth article in the series of eight, opened in September and published monthly in the Global Communications Newsletter, which covers all areas of IEEE ComSoc Member Relations. In this series of articles, I introduce the seven Member Relations Directors (namely: Sister and Related Societies; Membership Programs Development; AP, NA, LA, EAME Regions; Marketing and Industry Relations) and the Chair of the Women in Communications Engineering (WICE) Standing Committee. In each article, one by one they present their activities and plans. [ABSTRACT FROM PUBLISHER]

Remote spectral imaging of coastal areas can provide valuable information for their sustainable management and conservation of their biodiversity. Unfortunately, such areas are very sensitive to changes due to human activity, natural phenomenon, introduction of non-native species, and climate change. Thus, the main objective of this research is the implementation of a robust image processing methodology to produce accurate bathymetry maps in shallow coastal waters using high-resolution multispectral WorldView-2/3 satellite imagery for the monitoring at the maximum spatial and spectral resolutions. Two different island ecosystems have been selected for the assessment, since they stand out for their richness in endemic species and they are more vulnerable to climate change: Cabrera National Park and Maspalomas Natural Protected area, located in the Balearic and Canary Islands, Spain, respectively. In addition, a third example to show the applicability of the mapping methodology to monitor the construction of a new port in Granadilla (Canary Islands) is presented. Contributions of this work focus on improving the preprocessing methodology and, mainly, on the proposal and assessment of new satellite-derived regression and machine learning bathymetric models, which have been validated and compared with respect to measured reference bathymetry. After a thorough analysis of nine techniques, using visual and quantitative statistical parameters, ensemble learning approaches have demonstrated excellent performance, even in challenging scenarios up to 35-m depth, with mean RMSE values around 2 m. [ABSTRACT FROM AUTHOR]

Contribution: This article explores the factors favoring the enrollment in engineering studies in Spain, analyzing gender differences. Background: Understanding the motivation of choosing engineering studies is very important in order to strengthen this choice in future promotions in Spain, considering that it is well below the average of the European Union at the present time. Research Questions: What are the main factors that influence students to choose engineering studies? Are there any noticeable differences between those affecting male and female students? Methodology: Data were collected from a survey completed by 624 students and an exploratory study was performed extracting five components. Independent sample $T$ -tests were used to determine significant differences between the answers of males and females. Findings: The factors found in the exploratory analysis were “Interest and development,” “Career advice and previous contact,” “Outcome expectations,” “Social influences” and “Not preferred option.” Significant differences between the answers given by males and females were also found. The outcome of this study is important for the development of new interventions aimed to increase interest, enrollment, and retention of engineering students, especially among females. [ABSTRACT FROM AUTHOR]