The Economics of Wind Power with Energy Storage

We develop a nonlinear mathematical optimization program for investigating the economic and environmental implications of wind penetration in electrical grids and evaluating how hydropower storage could be used to offset wind power intermittence. When wind power is added to an electrical grid consisting of thermal and hydropower plants, it increases system variability and results in a need for additional peak-load, gas-fired generators. Our empirical application using load data for Alberta’s electrical grid shows that 32% wind penetration (normalized to peak demand) results in a net cost increase of $C5.20/ MWh, while 64$12.50/MWh. Costs of reducing CO2 emissions are estimated to be $41-$56 per t CO2 . When pumped hydro storage is introduced in the system or the capacity of the water reservoirs is enhanced, the hydropower facility could provide most of the peak load requirements obviating the need to build large peak-load gas generators.Renewable energy, carbon costs, hydropower storage, mathematical programming

Time-frequency analysis for responses evoked by nociceptive and non-nociceptive stimuli based on EEG signals

In the pursuit of a system capable of measuring pain signals in humans we propose a method to differentiate those signals related to pain from those which are not. We performed a time-frequency analysis using the Gabor transform to have complete information about the spectrum and its behaviour through the time to study the main differences over the evoked potentials provoked by both nociceptive and somatosensory (non-nociceptive) stimulation. The setup of the experiment also allowed us to study the mismatch negativity and the differences between the potentials evoked by a deviant stimulus and the ones evoked by a standard stimulus according to the roving paradigm. The results show that nociceptive evoked potentials read over the scalp have more energy than the somatosensory evoked potentials, they also differ in the frequencies that are activated as well as the latencies where such frequencies are activated. These results were obtained after pre-processing the EEG signals mainly removing the artifacts running the independent component algorithm (ICA) which allowed us to have reliable results.Time-frequency analysis as a metric for measuring pain in an objective way Could we achieve an objective system to assess pain by reading information provided by our own brains? If we achieve such system it would bring huge implications and consequences in the way we read and treat pain. Motivited by this we decided to perform an analysis in the time-frequency domain to describe the electrical responses evoked by painful stimuli. Nowadays it is still quite normal going the doctor and being asked to rate the pain we are feeling from 0 to 10 where 0 is no pain, and 10 the worst pain ever felt. What a tricky question! Isn’t it? And it is going to be like that until we finally find the solution to objectively measure pain. However the biggest benefits would be found in the way medicine specialists approach the diseases they are treating, and a better diagnosis for their patients who would get the best part of this. Think about those patients who are not capable to communicate by themselves either after an accident or a brain damage but can still feel pain. Monitoring pain state would bring huge advantages in many situations we are dealing with today. In this work “Time-frequency analysis for responses evoked by nociceptive and non-nociceptive stimuli based on EEG signals” we addressed the problem of measuring the pain objectively, and we wanted to make this approach by finding the main differences between the electrical responses in our brain after a painful stimulus compared to the responses after a non-painful stimulus, and to do so, experiments were made with volunteers who received both painful and non-painful stimulation at the same time that the electrical signals from their scalps were recorded and we certainly found a good parameter to differentiate these two situations. However there’s always going to be a subjective component for pain, and every one of us has a different threshold for which a stimulation turns into a painful one, and that’s why the stimulation applied to participants was adjusted individually to ensure that they were feeling pain or that they were not in order to somehow eliminate this subjective component characteristic of pain. We based our research on the time-frequency domain analysis and the results allowed us to see three main differences: • The factor of attention may change the way we perceive pain. When the participants were paying attention to the stimulation itself, different responses were obtained even before the stimulus came. • The frequency of the electrical signals captured in our brain changes depending on the nature of the stimulation (painful or non-painful). For related-to-pain responses the information tends to be processed at higher frequencies compared to the responses provoked by non-painful stimulation. • The electrical signals captured in our scalp also change in amplitude depending on the type of stimulus (painful or no-painful). The energy reflected in the signals captured from the scalp after a painful stimulus was much larger. The results found in the present study will take us one step closer to obtain a system capable of matching a signal with some input parameters in order to estimate first of all the presence of pain (whether there’s pain or not) and second of all the level of pain. Written by Juan Pablo Lago

Engineering as a Mode of Acknowledging Worth: A Response to Wolterstorff’s Kuyper Prize Lecture

This paper is a response to Nicholas Wolterstorff\u27s 2014 Kuyper Prize Lecture given in the Miller Chapel at Princeton Theological Seminary and titled Art, Justice and Liturgy . Its purpose is to continue Wolterstorff\u27s discussion by considering the affinity that engineering has with art, liturgy, and justice – or, more precisely, the affinity that the practice of scientific innovation and design has with “the actions of paying absorbed attention to some work of the arts, of doing and seeking justice and of enacting the liturgy. It is an attempt to recognize engineering as a mode of acknowledging goodness

Thoughts from a College Student

It hurts to be invisible, it hurts to be in silence. But despite the fact that this is no longer my reality, I can still claim that it is hard to be a minority. It is hard to be away from home. It is not easy being an international student. Posting about the experiences of a college student from Paraguay from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/thoughts-from-a-college-student

Climate Impacts of Deforestation/Land-Use Changes in Central South America in the PRECIS Regional Climate Model: Mean Precipitation and Temperature Response to Present and Future Deforestation Scenarios

Deforestation/land-use changes are major drivers of regional climate change in central South America, impacting upon Amazonia and Gran Chaco ecoregions. Most experimental and modeling studies have focused on the resulting perturbations within Amazonia. Using the Regional Climate Model PRECIS, driven by ERA-40 reanalysis and ECHAM4 Baseline model for the period 1961–2000 (40-year runs), potential effects of deforestation/land-use changes in these and other neighboring ecoregions are evaluated. Current 2002 and estimated 2030 land-use scenarios are used to assess PRECIS's response during 1960–2000. ERA-40 and ECHAM4 Baseline driven runs yield similar results. Precipitation changes for 2002 and 2030 land-use scenarios, while significant within deforested areas, do not result in significant regional changes. For temperature significant changes are found within deforested areas and beyond, with major temperature enhancements during winter and spring. Given the current climate, primary effects of deforestation/land-use changes remain mostly confined to the tropical latitudes of Gran Chaco, and Amazonia

Hands-on training in Nonimaging Optics for SME's: the SMETHODS experience

A 5-day training in Nonimaging Optics for European SME’s employees was carried out in June 2012 in the framework of the FP7 funded Support Action "SMETHODS". The training combined theoretical introduction and hands-on practice. The experience was very positive, and the lessons learned will improve the next scheduled sessions. Introduction The FP7 funded Support Action "SMETHODS" [1] is an initiative of seven European academic institutions to strengthen Europe's optics and photonics industry, which has started on 1 September 2011. Participation in training sessions is free for participants, who are selected with priority will be given to employees of small and medium sized European enterprises (SMEs). The consortium in SMETHODS is formed by seven partners that are the most prominent academic institutions in optical design in their countries. Through fully integrated collaborative training sessions, the consortium provides professional assistance as well as hands-on training in a variety of design tasks in four domains: (1) imaging optics, (2) nonimaging optics, (3) wave optics, and (4) diffractive optics. For each of this domains domain, 5-day training sessions are scheduled to be hold in different locations throughout Europe, four times in two years, the teach four times in a 2.5 years period

Freeform optics for photovoltaic concentration

Freeform surfaces are the key of the state-of-the-art nonimaging optics to solve the challenges in concentration photovoltaics. Different families (FK, XR, FRXI) will be presented, based on the SMS 3D design method and Köhler homogenization

A quick and effective estimation of algal density by turbidimetry developed with Chlorella vulgaris cultures

El uso de Chlorella vulgaris Beijerinck como alimento para el zooplancton implica la necesidad de optimizar el cultivo de algas para mantener su crecimiento en el tiempo. En este trabajo se desarrolló un método que relaciona la densidad del cultivo con la turbidez para estimar la biomasa algal. Esta técnica se ha mejorado mediante la aplicación del análisis digital para el recuento de las algas que promueve la exactitud y reduce el disturbio en el cultivo, con obtención rápida y fácil de resultados repetibles. Se realizaron dos cultivos de C. vulgaris en recipientes de 3 L con aireación e iluminación continua (50 µmol fotones m–2 ·s–1 a 660 nm), alcanzando 214 y 280 NTU, respectivamente. El recuento de las muestras se realizó por medio de imágenes digitales tomadas con un microscopio invertido. Se aplicaron dos técnicas para el recuento de las alícuotas: la sedimentación directa y la sedimentación con homogeneización previa. Con el fin de comparar el ajuste de ambos métodos de sedimentación, las fotografías fueron tomadas en los sectores central, medio y periférico de la cámara de sedimentación. Para ambas técnicas se contaron un mínimo de 17 individuos imagen–1 y un máximo de 404 individuos imagen–1, con un tiempo promedio de un minuto por imagen. A niveles bajos de turbidez (< 40 NTU) la dispersión de los datos fue similar entre ambas técnicas (rango error: 16-60 %). Para niveles superiores de turbidez, en la técnica de sedimentación directa se observó un mayor rango de error (31-50 %) mientras que en la técnica con homogenización previa osciló entre 5 y 13 %. El análisis de regresión evidenció un bajo ajuste de los datos (67 %), que en la sedimentación sin homogeneización responde a un patrón reiterado de aumento de densidad algal desde la periferia hacia el centro de la cámara de sedimentación. La inclusión de una homogeneización previa promueve un mejor ajuste del modelo (99 %) y determina un incremento en la consistencia del método. Con los resultados obtenidos se demuestra que la técnica turbidimétrica desarrollada puede ser utilizada con éxito en cultivos de especies de algas cuyas formas geométricas sean reconocidas por el procesador de imágenes.The use of Chlorella vulgaris Beijerinck as a food source for zooplankton requires the optimization of algal-culture conditions for prolonged growth maintenance. In this study, we developed a method that relates algal density to culture turbidity to estimate culture biomass. This method was improved by applying digital analysis for algal counting, which promotes accuracy, low culture disturbance, easy repetition and the rapid acquisition of results. Two 3-L cultures of C. vulgaris, maintained for two weeks with continuous lighting (eight light-emitting diodes at 50 µmol photons m–2 ·s–1, at 660 nm) and aerators to prevent algal sedimentation, reached turbidities of 214 and 280 NTUs, respectively. Sample counting was performed using digital images obtained with an inverted microscope. Aliquot sedimentation was compared with or without previous homogenization through photographs taken in the central, middle, and peripheral sectors of the Utermöhl settling chambers. For each procedure, we counted between 17 and 404 individuals image–1, requiring, on average, one minute image–1. At low turbidity (< 40 NTU), the data dispersion was similar between the two protocols (error range, 16 to 60 %); at higher turbidity, the direct sedimentation alone gave a larger error (31-50 %) than with prior homogenization (5-13 %). Regression analysis at low data fit (67 %) suggested that the sedimentation heterogeneity of non-homogenized samples corresponded to a pattern of settled algae having increasing density from the periphery to the centre of the chamber, but with homogenization, a better model fitting (99 %) resulted, contributing to greater consistency with that procedure. We consider that this turbidometric protocol could be used successfully with cultures of algae that have geometrical shapes recognizable by the image software.Fil: Ferrando, Noelia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Benitez, Hernan Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Gabellone, Nestor Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Claps, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Altamirano, Pablo Rodrigo. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentin

User clustering based on keystroke dynamics

The PAM clustering algorithm is applied on the Si6 keystroke dataset in order to identify sessions of the same users. A number of heuristical outlier lters based on statistical properties of keystroke latencies are proposed and run on the dataset. Di erent tests are performed varying the number of digraphs that compose each observation and its dimensionality, in order to verify the assumption that more data gives a better quality of clustering and to estimate the minimum required number of dimensions. The number of clusters is estimated through the silhouette algorithm. Resulting clustering accuracy is measured by means of the F-measure, showing the viability of user identi cation through keystroke analysis.Presentado en el V Workshop Arquitectura, Redes y Sistemas Operativos (WARSO)Red de Universidades con Carreras en Informática (RedUNCI