Rule-based system to detect energy efficiency anomalies in smart buildings, a data mining approach

The rapidly growing world energy use already has concerns over the exhaustion of energy resources andheavy environmental impacts. As a result of these concerns, a trend of green and smart cities has beenincreasing. To respond to this increasing trend of smart cities with buildings every time more complex,in this paper we have proposed a new method to solve energy inefficiencies detection problem in smartbuildings. This solution is based on a rule-based system developed through data mining techniques andapplying the knowledge of energy efficiency experts. A set of useful energy efficiency indicators is alsoproposed to detect anomalies. The data mining system is developed through the knowledge extracted bya full set of building sensors. So, the results of this process provide a set of rules that are used as a partof a decision support system for the optimisation of energy consumption and the detection of anomaliesin smart buildings.Comisión Europea FP7-28522

Clasificación de registros de mapeado cardíaco en fibrilación ventricular

El presente trabajo estudia las modificaciones intrínsecas que el ejercicio físico produce en la respuesta cardíaca durante fibrilación ventricular (FV). Para ello se plantea el desarrollo de clasificadores (RL; regresión logística y ELM; Extreme Learning Machine) que diferencien entre el grupo control y los sujetos entrenados. Como parámetros de entrada a los clasificadores se han considerado dos relacionados con el espectro de la señal (FD: frecuencia dominante, y EN: energía normalizada), y otros relacionados con la regularidad y organización de las ondas de activación local, OAL, (IR: índice de regularidad y NO: número de ocurrencias). Se ha realizado un análisis de regiones de interés (ROI) de los tres primeros parámetros para valorar su uniformidad espacial. El trabajo tiene un doble objetivo: estudiar las capacidades de los distintos clasificadores y obtener información acerca de la importancia de las variables a la hora de realizar la clasificación. Se analizaron registros de mapeado cardíaco correspondientes a dos grupos: control (G1: sin entrenamiento, N=10) y entrenados (G2, N=9). Del estudio de las capacidades de ambos clasificadores, se puede observar cómo la ELM obtiene mejores índices de funcionamiento que la RL. Si se analiza el producto sensibilidad por especificidad en el conjunto de validación, se obtiene un 60.73% con la RL y un 72.37% con la ELM. En cuanto al análisis de variables, los resultados obtenidos sugieren que los cambios intrínsecos en FV debidos al ejercicio físico están relacionados con la regularidad morfológica y la uniformidad espectral de las señales de activación del tejido cardíaco

Islanding detection in grid-connected power converters using harmonics due to the non-ideal behavior of the inverter

This paper analyzes the use of the voltage distortions in PWM voltage-source-inverters (VSIs) caused by the non-ideal behavior of the inverter for islanding detection purposes. The non-ideal characteristic of the inverters, mainly due to the dead-time needed to have safe commutations, produces fundamental frequency dependent harmonics (-5th, 7th...) in the output voltage. Although these harmonics are in principle an unwanted effect, since they reduce the power quality, they can potentially be used for islanding detection purposes. The physical principles of the method would be the same as for high frequency signal injection methods that have already been proposed but without the need of injecting a high frequency signa

Sensorless control of doubly-fed induction generators based on stator high frequency signal injection

High frequency signal injection based methods have been widely investigated for sensorless position/speed control of induction machines (IMs), permanent magnet synchronous machines (PMSMs) and more recently for doubly fed induction generators (DFIGs). When used with IMs and PMSMs, the high frequency signal is injected in the stator windings, an asymmetric (salient) rotor being required for this case. Contrary to this, both stator and rotor terminals are accessible and sensored in DFIGs, being therefore possible to inject the high frequency signal either in the stator or the rotor terminals. As consequence of this, the method can be used even if the machine is non-salient. In the implementation of the method with DFIGs, the high frequency voltage signal is typically injected in the rotor, the high frequency components (voltages of currents) induced in the stator being used for rotor position estimation. A drawback of this alternative is that the method is sensitive to the grid impedance in the stator side, which will be affected by the grid configuration, and is normally unknown. This paper proposes the sensorless control a DFIG injecting the high frequency voltage in the stator side, and using a high frequency current cancellation strategy in the rotor side. The main advantage of the proposed strategy is that the estimated position is independent of the grid characteristic

Coordinated operation of parallel-connected inverters for active islanding detection using high frequency signal injection

The high frequency impedance measured at the terminals of inverters connected in a microgrid by means of the injection of a small magnitude, high frequency voltage, has been shown to be a reliable metric to detect islanding. While the implementation of this method is simple when only an inverter injects the high frequency signal, this case is of limited applicability. On the other hand, several concerns arise when multiple inverters work in parallel, primarily due to risk interference among inverters. Islanding detection using high frequency signal injection in microgrids with multiple parallel-connected inverters is studied in this paper. A strategy for the coordinated operation of the inverters, without the need of communications or pre-established roles is proposed. Simulation and experimental results will be provided to demonstrate the viability of the concep

Islanding detection in three-phase and single-phase systems using pulsating high frequency signal injection

This paper analyzes the use of pulsating high frequency signal injection for islanding detection purposes. Active islanding detection using high frequency signal injection is an appealing option due to its reduced non-detection zone, reduced cost and ease of implementation. The use of a rotating high frequency signal has been reported and analyzed. However, this method can only be applied to three-phase systems. In this paper, the use of a pulsating high frequency signal injection is proposed. While it uses the same principles as rotating signal injection, it can be applied to both threephase and single-phase system

Redox-dependent and redox-independent functions of Caenorhabditis elegans thioredoxin 1

Thioredoxins (TRX) are traditionally considered as enzymes catalyzing redox reactions. However, redox-independent functions of thioredoxins have been described in different organisms, although the underlying molecular mechanisms are yet unknown. We report here the characterization of the first generated endogenous redox-inactive thioredoxin in an animal model, the TRX-1 in the nematode Caenorhabditis elegans. We find that TRX-1 dually regulates the formation of an endurance larval stage (dauer) by interacting with the insulin pathway in a redox-independent manner and the cGMP pathway in a redox-dependent manner. Moreover, the requirement of TRX-1 for the extended longevity of worms with compromised insulin signalling or under calorie restriction relies on TRX-1 redox activity. In contrast, the nuclear translocation of the SKN-1 transcription factor and increased LIPS-6 protein levels in the intestine upon trx-1 deficiency are strictly redox-independent. Finally, we identify a novel function of C. elegans TRX-1 in male food-leaving behaviour that is redox-dependent. Taken together, our results position C. elegans as an ideal model to gain mechanistic insight into the redox-independent functions of metazoan thioredoxins, overcoming the limitations imposed by the embryonic lethal phenotypes of thioredoxin mutants in higher organisms.NIH Office of Research Infrastructure P40 OD010440Spanish Ministry of Economy and Competitiveness BFU2015- 64408-PFondo Social Europeo BFU2015- 64408-PNational Institute of Allergy and Infectious Diseases of the National Institutes of Health R01AI07640

Moving Learning Machine Towards Fast Real-Time Applications: A High-Speed FPGA-based Implementation of the OS-ELM Training Algorithm

Currently, there are some emerging online learning applications handling data streams in real-time. The On-line Sequential Extreme Learning Machine (OS-ELM) has been successfully used in real-time condition prediction applications because of its good generalization performance at an extreme learning speed, but the number of trainings by a second (training frequency) achieved in these continuous learning applications has to be further reduced. This paper proposes a performance-optimized implementation of the OS-ELM training algorithm when it is applied to real-time applications. In this case, the natural way of feeding the training of the neural network is one-by-one, i.e., training the neural network for each new incoming training input vector. Applying this restriction, the computational needs are drastically reduced. An FPGA-based implementation of the tailored OS-ELMalgorithm is used to analyze, in a parameterized way, the level of optimization achieved. We observed that the tailored algorithm drastically reduces the number of clock cycles consumed for the training execution up to approximately the 1%. This performance enables high-speed sequential training ratios, such as 14 KHz of sequential training frequency for a 40 hidden neurons SLFN, or 180 Hz of sequential training frequency for a 500 hidden neurons SLFN. In practice, the proposed implementation computes the training almost 100 times faster, or more, than other applications in the bibliography. Besides, clock cycles follows a quadratic complexity O(N 2), with N the number of hidden neurons, and are poorly influenced by the number of input neurons. However, it shows a pronounced sensitivity to data type precision even facing small-size problems, which force to use double floating-point precision data types to avoid finite precision arithmetic effects. In addition, it has been found that distributed memory is the limiting resource and, thus, it can be stated that current FPGA devices can support OS-ELM-based on-chip learning of up to 500 hidden neurons. Concluding, the proposed hardware implementation of the OS-ELM offers great possibilities for on-chip learning in portable systems and real-time applications where frequent and fast training is required

Análisis tiempo-frecuencia de mapas de activación cardíaca en fibrilación ventricular

El análisis de mapas de activación permite investigar la estructura de la fibrilación ventricular cardíaca (FV). El presente trabajo plantea una revisión de la utilización de objetos de interés (blobs), usados en procesado de imágenes y aplicados también a mapas de activación cerebral y cardíaca, mediante su generación a partir de representaciones tiempo-frecuencia de registros FV. Su estudio proporciona información sobre qué frecuencias de la señal están presentes en un instante dado, así como su distribución espacial. También permiten determinar el momento en que una determinada frecuencia aparece y desaparece de cada electrodo, por lo que constituye una herramienta interesante para analizar los mecanismos de generación y mantenimiento de la FV

Aprendizaje por Proyectos: Una Aproximación Docente al Diseño Digital Basado en VHDL

Abstract-- Digital design based on hardware description languages is difficult for students, especially when the course covers from basics to advanced design systems and hardware implementation topics. This paper describes the proposal of a course where students have basic knowledge in digital design but null knowledge in hardware description languages as VHDL and FPGA (Field Programmable Gate Array) devices. Using Project Based Learning (PBL), this proposal allows increasing the learning curve, improving motivation and achieving some of the indications given by the European High Education Area (EHEA)