131 research outputs found

    Energy Storage Needs in Interconnected Systems Using the Example of Germany and Austria

    Get PDF
    The share of renewable energies on the net electricity consumption is rising steadily. Especially intermittent, non-controllable sources like wind and sun are gaining importance. With an installed amount of non-controllable power that exceeds the yearly peak load, situations can occur with a surplus of energy in electricity supply systems. This surplus will rise strongly with the share of fluctuating renewable energies on the net electricity consumption. A lot of studies and experts come to the conclusion that energy storage will be needed to handle these surpluses. The questions that still have to be answered are when and how. Especially the German electricity system will have very high storage needs because of a very strong and fast development of wind and solar power. There are a lot of technologies and approaches to overcome this problem. However, Pumped Hydro Energy Storage (PHES) systems are up to date the most efficient and economic bulk energy storage technology. On the one side there are no high potentials in natural sites for the installation of PHES schemes in Germany. On the other side the Austrian PHES system has still a very high potential. Up so far, the prospects are used just to a small amount. Especially the seasonal Hydro Energy Storage (HES) still holds a very high potential. In this paper the combination of the Austrian and the German energy supply system will be investigated with respect to the development of renewable energies. The overall energy storage needs are evaluated for each country as well as in the combined system, taking also into account the development and the influence of the transmission system capacity between the two countries

    Podcasting und seine Nutzung

    Get PDF
    Das Erkenntnisinteresse hinter der Arbeit ist, zu erfahren, unter welchen Umständen Podcasts genutzt werden, und auf welche Art und Weise Podcast-Nutzer sich mit diesem Medium auseinandersetzen. Weiters sollen Unterschiede und/oder Gemeinsamkeiten zu anderen Formen auditiver Mediennutzung aufgezeigt werden. Podcasts sollen somit innerhalb auditiver (und auch neuer) Medien eingeordnet werden können. Die Daten für diese Arbeit wurden mittels der Methode der Befragung erhoben. Speziell wurde eine Form der Online-Befragung angewandt. Die Befragung war so kurz wie möglich gehalten und wies einen durchschnittlichen Standardisierungsgrad auf. Links zur Befragung wurden auf verschiedenen Online-Plattformen für Podcasting veröffentlicht. Damit war ein Feldzugang mit möglichst wenig Streuverlust gewählt. Die Ergebnisse der Arbeit reichen von der Nutzerdemographie bis hin zu der Nutzungsart, den Gründen der Nutzung etc. Podcast-Nutzer sind im Schnitt 32 Jahre alt. Über 80% der Podcast-Nutzer sind unter 40 Jahren alt. Die Podcast-Nutzerschaft ist zu 76,1% männlich. Außerdem kann ein relativ hoher Bildungsgrad der Podcast-Nutzer nachgewiesen werden. Es konnten interessante Informationen zu den genutzten Inhalten erhoben werden. So sind Unterschiede in der Nutzung von Podcasts entweder zu Informations- oder zu Unterhaltungszwecken bearbeitet worden. Der Ort der Nutzung ist ein weiterer Punkt, über den durch diese Arbeit Auskunft erlangt werden konnte. So ist die Nutzung zu Hause z.B. stark bevorzugt. Unerwartet sind die Ergebnisse zur Rückkopplungsfunktion. Diese scheint seltener genutzt zu werden als ursprünglich angenommen. Es kann durch die Ergebnisse ein aufschlussreiches Bild nicht nur von der Podcast-Nutzung und den Nutzern gezeichnet werden, es können dadurch auch Aufschlüsse über Web 2.0 gesamt gewonnen werden

    Service learning in business education: What perceptions and expectations do undergraduate and graduate students have of service-learning courses?

    Get PDF
    Service Learning is a modern teaching-learning concept, which combines curricular content with supporting charitable organizations. The effects of courses using this concept on the students’ competences development has already been described in empirical studies. Within these studies the aspects regarding the instructional design were less emphasized unlike in this paper in which they are focused on. In addition to a conceptual foundation of service-learning and a literature review on the impact of service-learning, two didactic prototypes will be presented in the form of empirical case studies. The focus of this research is to describe the attitudes and perceptions of undergraduate and graduate students attending service-learning courses and which conclusions can be drawn on the instructional design. In this article, the concept of service-learning is understood as a course- and credit-based learning and teaching method (in contrast to community-service), which require a specific instructional design to evolve purposeful and curricular learning connections between the course and service projects outside the course

    The Error is the Feature: how to Forecast Lightning using a Model Prediction Error

    Full text link
    Despite the progress within the last decades, weather forecasting is still a challenging and computationally expensive task. Current satellite-based approaches to predict thunderstorms are usually based on the analysis of the observed brightness temperatures in different spectral channels and emit a warning if a critical threshold is reached. Recent progress in data science however demonstrates that machine learning can be successfully applied to many research fields in science, especially in areas dealing with large datasets. We therefore present a new approach to the problem of predicting thunderstorms based on machine learning. The core idea of our work is to use the error of two-dimensional optical flow algorithms applied to images of meteorological satellites as a feature for machine learning models. We interpret that optical flow error as an indication of convection potentially leading to thunderstorms and lightning. To factor in spatial proximity we use various manual convolution steps. We also consider effects such as the time of day or the geographic location. We train different tree classifier models as well as a neural network to predict lightning within the next few hours (called nowcasting in meteorology) based on these features. In our evaluation section we compare the predictive power of the different models and the impact of different features on the classification result. Our results show a high accuracy of 96% for predictions over the next 15 minutes which slightly decreases with increasing forecast period but still remains above 83% for forecasts of up to five hours. The high false positive rate of nearly 6% however needs further investigation to allow for an operational use of our approach.Comment: 10 pages, 7 figure

    Social Entrepreneurship Education durch Service Learning - eine Untersuchung auf Basis zweier Pilotstudien in der wirtschaftswissenschaftlichen Hochschulbildung

    Get PDF
    Social Entrepreneurship verbindet unternehmerisches Denken und Handeln mit sozialen Herausforderungen der Zivilgesellschaft. Didaktisch gewendet, bedarf es dafür Lehr-Lernformen, die neben fachlich-methodischen Fähigkeiten auch diese sozialen Herausforderungen in den Blick nehmen. An dieser Stelle scheint das Veranstaltungsformat Service Learning eine Passung aufzuzeigen, da hier curriculare Inhalte mit gemeinnützigem Engagement verbunden werden. Ziel des vorliegenden Beitrages ist es, die Potentiale von Service Learning für eine Social Entrepreneurship Education an Hochschulen konzeptionell herauszuarbeiten und empirisch zu illustrieren. Hierfür werden Ergebnisse zweier Pilotstudien zur Wirkung von Service?Learning-Arrangements an deutschsprachigen Universitäten vorgestellt. Im Ergebnis zeigt sich, dass Studierende bei der Bearbeitung sozialer Herausforderungen von gemeinnützigen Organisationen einen Problem- und Anwendungsbezug wahrnehmen sowie die Selbstwirksamkeit und ein Nachdenken über das eigene Selbstbild gefördert werden können. 19.06.2015 | Karl-Heinz Gerholz (Paderborn) & Peter Slepcevic-Zach (Graz

    Unrecognized High Occurrence of Genetically Confirmed Hereditary Carnitine Palmitoyltransferase II Deficiency in an Austrian Family Points to the Ongoing Underdiagnosis of the Disease

    Get PDF
    Adult muscle carnitine palmitoyltransferase (CPT) II deficiency is a rare autosomal recessive disorder of long-chain fatty acid metabolism. It is typically associated with recurrent episodes of exercise-induced rhabdomyolysis and myoglobinuria, in most cases caused by a c.338C > T mutation in the CPT2 gene. Here we present the pedigree of one of the largest family studies of CPT II deficiency caused by the c.338C > T mutation, documented so far. The pedigree comprises 24 blood relatives of the index patient, a 32 year old female with genetically proven CPT II deficiency. In total, the mutation was detected in 20 family members, among them five homozygotes and 15 heterozygotes. Among all homozygotes, first symptoms of CPT II deficiency occurred during childhood. Additionally, two already deceased relatives of the index patient were carriers of at least one copy of the genetic variant, revealing a remarkably high prevalence of the c.338C > T mutation within the tested family. Beside the index patient, only one individual had been diagnosed with CPT II deficiency prior to this study and three cases of CPT II deficiency were newly detected by this family study, pointing to a general underdiagnosis of the disease. Therefore, this study emphasizes the need to raise awareness of CPT II deficiency for correct diagnosis and accurate management of the disease

    Unrecognized High Occurrence of Genetically Confirmed Hereditary Carnitine Palmitoyltransferase II Deficiency in an Austrian Family Points to the Ongoing Underdiagnosis of the Disease.

    Get PDF
    Adult muscle carnitine palmitoyltransferase (CPT) II deficiency is a rare autosomal recessive disorder of long-chain fatty acid metabolism. It is typically associated with recurrent episodes of exercise-induced rhabdomyolysis and myoglobinuria, in most cases caused by a c.338C > T mutation in the CPT2 gene. Here we present the pedigree of one of the largest family studies of CPT II deficiency caused by the c.338C > T mutation, documented so far. The pedigree comprises 24 blood relatives of the index patient, a 32 year old female with genetically proven CPT II deficiency. In total, the mutation was detected in 20 family members, among them five homozygotes and 15 heterozygotes. Among all homozygotes, first symptoms of CPT II deficiency occurred during childhood. Additionally, two already deceased relatives of the index patient were carriers of at least one copy of the genetic variant, revealing a remarkably high prevalence of the c.338C > T mutation within the tested family. Beside the index patient, only one individual had been diagnosed with CPT II deficiency prior to this study and three cases of CPT II deficiency were newly detected by this family study, pointing to a general underdiagnosis of the disease. Therefore, this study emphasizes the need to raise awareness of CPT II deficiency for correct diagnosis and accurate management of the disease
    corecore