177,158 research outputs found
LaMedica : eine multimediale online Lehr- und Lernplattform
No full textDas Projekt LaMedica (http://www.lamedica.de) hat zum Ziel, eine multimediale Lehr- und Lernplattform zu entwickeln, Inhalte für die Medizin zu erstellen und diese in die Lehre zu implementieren. Es wurde eine on-line Autorenumgebung geschaffen, die sehr unterschiedliche didaktische Ansätze unterstützt: systematische und vernetzte Wissensvermittlung, fallbasiertes Lernen, Erstellung von Vorlesungen und Lernerfolgskontrolle. Die Lehrinhalte können zielgruppenspezifisch aufbereitet und dargestellt werden und richten sich insbesondere an Studenten, Ärzte in der Weiterbildung und Fachärzte. Eine on-line Medien-Datenbank unterstützt die Wiederverwendung und den Austausch von Inhalten auf der Basis eines Content-Management-Systems durch Verwendung des Learning Objects Metadata Standards (LOM). Die Förderung erfolgt durch das BMBF (FKZ NM054A).The project LaMedica (http://www.lamedica.de) has as its aim the development of a multimedia teaching and learning platform, the compilation of contents for medicine and the implementation of these in the teaching process. An on-line author environment was created which supports a variety of didactic approaches: systematic and networked communication of knowledge, case-based learning, the creation of lectures and learning sequence checks. The teaching contents can be edited and illustrated, and are aimed in particular at students, doctors in continuing education and specialists. An on-line media databank supports the re-use and the exchange of contents on the basis of a content management system through the use of the Learning Objects Metadata standards (LOM). Funding is provided by the Federal Ministry for Education and Research (FKZ NM054A)
Renewable energy integration system: Economic, environmental and energetic assessments
No full textThe paper deals with an efficient energy management system that, starting from the analysis of current consumption patterns, suggests how to improve the overall energy efficiency of an industrial site
Time-varying harmonic currents from large penetration electronic equipment
No full textThe chapter deals with the characterization of time varying harmonic currents from large penetration electronic equipment.
The time-varying characterization of single-phase NL appliances of large penetration into end-use such as desktop PC, printer, photocopier and cell phone battery charger has been presented first. The time-varying behavior of harmonics has been investigated through the use of specific measurement equipment allowing continuous harmonic monitoring. Pdf’s and distribution functions have been calculated for the large amount of data made available from the monitoring activity.
Then, an experimental procedure has been presented which helps predict the mutual influence between several single-phase electronic equipment and the LV distribution network.
Two parametrical models can be identified from monitoring results. The models are expressed via some curves that have been defined: 1) attenuation curves; 2) impact curves. The attenuation curves allow to parametrically estimate the effects of cancellation phenomena on net harmonic currents. The impact curves allow to parametrically predict the NL load influence on voltage harmonic distortion at PCC
IEC Std. 61000-3-2 harmonic current emission limits in practical systems: need of considering loading level and attenuation effects
No full text
Distorsione armonica in un sistema di trasporto elettrificato metropolitano: indagine sulle linee di Roma
No full textDistorsione armonica nelle reti di distribuzione: criteri e tecniche di simulazione
No full textNonostante l'ampia disponibilità in letteratura di modelli e metodi per il calcolo del regime armonico di sistemi elettrici di potenza, si riscontrano spesso, sui risultati ottenibili, margini di incertezza non trascurabili in termini quantitativi; ciò in particolare quando non si disponga di una dettagliata e approfondita conoscenza dei vari componenti del sistema da esaminare. Una tale conoscenza risulta peraltro oggettivamente difficile nella pratica sia per la complessità dei sistemi stessi che per l'indeterminazione o la variabilità casuale di alcuni parametri. Restando tuttavia indispensabile l'approccio analitico per la predeterminazione della distorsione armonica nella progettazione di nuovi sistemi o nell'analisi di modifiche di sistemi esistenti, occorrono dei criteri orientativi che consentano di valutare l'accettabilità di semplificazioni e approssimazioni nella riproduzione modellistica dei vari componenti d'impianto. Nella memoria viene analizzata, nell'ambito di un sistema di distribuzione, l'influenza che assumono i diversi gradi di dettaglio nella formulazione dei modelli simulativi sull'attendibilità dello studio; in particolare vengono esaminate alcune possibili rappresentazioni della rete di trasmissione AT, delle linee MT, dei carichi e delle sorgenti disturbanti. Vengono inoltre mostrate le modalità utilizzate per ovviare alla mancanza di informazioni e per evitare macroscopiche inesattezze
Estimation of net harmonic currents produced by non-linear appiances in residential areas
No full textA methodologic approach to define the railway junctions capacity
No full textThe paper reports a methodologic approach to define the capacity of railway junctions. The railway traffic increase, together with the improvement of passenger comfort, has produced a greater need for electricity. Consequently, solutions to augment the railway system capacity, including railway junctions, have to be achieved. In order to design new plants and to improve or certificate the existing ones, simulation of the overall railway system is necessary. In this paper the Authors propose a guideline with a theoretical approach to study the capacity of railway junctions
- …
