1,721,063 research outputs found
A passivity based, system reference frame approach for decentralized stability analysis and control design in future power grids
No full textOver the last decades, power systems have been through critical changes as a result of the
worldwide efforts to decelerate climate change and global warming. Such changes were
the introduction of new generation and storage technologies, and the rapid increase of the
share of Renewable Energy Sources (RES) in power generation. Although these advances
contributed to technological and economic development, they have introduced numerous
issues that were not previously encountered in traditional power grids. Specifically, the
gradual replacement of the large fossil-fueled plants with a large number of small sparselylocated
RES resulted in the significant decrease of system rotational inertia and the emergence
of serious stability-related problems.
Despite the latest decisive steps in the area of stability analysis and control design,
existing power systems are still in danger due to the continuously increasing challenges they
encounter. An effective way to overcome these problems is the adoption of more accurate
dynamical models for both the network and the power system components within stability
studies. Such accurate modeling will not only assist in the design of more effective control
mechanisms, but it will provide useful insights regarding the stability and the reliability of
the system.
The current thesis aims to address the above problems by introducing a novel approach
for decentralized stability analysis and control design in existing and future power grids
wherein more detailed dynamical models are employed. The proposed approach relies upon
the transformation of both the network and the bus dynamics into the system reference
frame instead of each bus local dq coordinates. In particular, this transformation allows the
formulation of the network equations as an input-output system which we show it is passive
even if the network’s lossy and dynamic nature is taken into account. The passivity property
of the adopted network model along with the local passivity conditions imposed on a broad
class of bus dynamics guarantee the asymptotic stability of the whole power network in a
completely decentralized manner. The use of such a general representation also facilitates
the incorporation of more accurate dynamical models for the power system components
and their control mechanisms, even though their inclusion in such a decentralized analysis
has been difficult. A further detailed discussion regarding the advantages of the presented approach for the reliable and robust operation of the future low-inertia power grids as well
as the design of more effective distributed control mechanisms is provided. The proposed
stability analysis framework is finally verified through realistic applications and simulations
on several testbed systems such as the Two Area Kundur, the IEEE 68 Bus test systems and
the IEEE 37 Node test feeder.Complete
Internet Of Things (IOT) For Environmental Monitoring - Manufacture Of An Intergraded Air Quality Identification Device Ιn Vehicles
No full textIn the present study an attempt was made to construct a system that can detect the air quality in a car and warn the driver and his passengers in case the air quality in the cabin is not of good quality. Initially, the objectives of the project are presented as well as the existing knowledge on this subject. Also given is the difference and innovation of this construction from other similar constructions that already exist, a general description of the construction as well as the description of the material used. The sensors are examined one by one, seeing the usefulness of each one as well as the suitability of the equipment used. A prediction is then made of the factors that can affect the measurements. Then the experimental objectives and what should be considered most during the experiments are mentioned. Below are the normal values that can be expected from the operation of the sensors in a normal environment. The following shows the correct placement of the sensors inside a car, which is very important for the correct operation of the experiment. Then the main objectives that the construction is intended to detect are named, their effect on humans from where and generally a few words about each objective. The benefits of clean air to people are also mentioned. The experimental design is presented, and the experiments performed one by one are explained. At the same time, we see the graphic representations that were made as well as the way they were made. There are two kinds of graphs in this study. One type is the graphics made for the purpose of checking the correct operation of the sensors and the other type of graphics made for the control of the system in the car. Finally, the conclusions drawn from the experiments were presented, difficulties encountered during the study were presented, the reasons why the measurements may be affected, and the presenters explained the results behind these results, and instructions and advice were given to continue this construction. in the future.Στην παρούσα μελέτη έγινε προσπάθεια να κατασκευαστεί ένα σύστημα που θα μπορεί να ανιχνεύσει την ποιότητα του αέρα σε ένα αυτοκίνητο και να προειδοποιεί τον οδηγό και τους συνεπιβάτες του σε περίπτωση που η ποιότητα του αέρα στην καμπίνα δεν είναι καλής ποιότητας. Αρχικά παρουσιάζονται οι στόχοι του έργου όπως επίσης και η υφιστάμενη γνώση για το θέμα αυτό. Επίσης δίνεται η διαφορά και η καινοτομία της κατασκευής αυτής από άλλες παρόμοιες κατασκευές που ήδη υπάρχουν, μια γενική περιγραφή της κατασκευής καθώς και περιγραφή όλου του υλικού που θα χρησιμοποιηθεί . Εξετάζονται οι αισθητήρες ένας προς ένας βλέποντας την χρησιμότητα του καθενός καθώς και ότι είναι κατάλληλός ο εξοπλισμός που χρησιμοποιήθηκε. Ακολούθως γίνεται μια πρόβλεψη από τους παράγοντες που μπορούν να επηρεάσουν τις μετρήσεις . Στην συνέχεια παρουσιάζονται οι πειραματικοί στόχοι και τι πρέπει να ληφθεί υπόψη περισσότερο κατά την διάρκεια των πειραμάτων. Στην συνέχεια φαίνονται οι φυσιολογικές τιμές που είναι αναμενόμενες από την λειτουργία των αισθητήρων σε φυσιολογικό περιβάλλον. Ακολούθως παρουσιάζεται η σωστή τοποθέτηση των αισθητήρων μέσα σε ένα αυτοκίνητο η οποία είναι πολύ σημαντική για την ορθή λειτουργία του πειράματος . Στην συνέχεια ονομάζονται οι κύριοι στόχοι που έχει σκοπό να ανιχνεύει η κατασκευή, η επίδραση τους προς τον άνθρωπο από που προέρχονται και γενικά λίγα λόγια για τον κάθε στόχο. Επίσης αναφέρονται τα ωφελήματα του καθαρού αέρα προς των άνθρωπο. Παρουσιάζεται το πειραματικό σχέδιο και εξηγούνται τα πειράματα που έγιναν ένα προς ένα. Παράλληλα βλέπουμε τίς γραφικές παραστάσεις που έγιναν καθώς και τον τρόπο που έγιναν. Υπάρχουν δύο είδη γραφικών παραστάσεων σε αυτή την μελέτη. Το ένα είδος είναι οι γραφικές που έγιναν με σκοπό τον έλεγχο της σωστής λειτουργίας των αισθητήρων και το άλλο είδος είναι οι γραφικές που έγιναν για τον έλεγχο λειτουργείας του συστήματος μέσα στο αυτοκίνητο. Τέλος παρουσιάστηκαν τα συμπεράσματα που λήφθηκαν από τα πειράματα παρουσιάστηκαν δυσκολίες που αντιμετωπίστηκαν κατά την διάρκεια της μελέτης, οι λόγοι για τους οποίους πιθανό να επηρεάστηκαν οι μετρήσεις και παρουσιαστήκαν εξηγήσεις πίσω από αυτά τα αποτελέσματα και δόθηκαν οδηγίες και συμβουλές ώστε να γίνει συνέχεια της κατασκευής αυτής στο μέλλων.Complete
API Design for Monitoring and Assessment of The Indoor Air Quality αt CUT Lecture Halls
No full textThe connection of objects to the internet that every person needed in their lives first appeared in 1999. From then until today, the Internet of Things (IoT) has seen rapid growth. With the help of radio frequencies, people can use many devices and interact with each other. Various smart devices today can stay connected and exchange data in real time with the help of IoT. The most common applications regarding smart devices are found in sensors.
A topic that is of particular importance is air filtration. To be able to control it at any time and in any space or environment. Undoubtedly, an open field of research is the discovery of new ways in which people can benefit from the use of air quality sensors. The aim of this work is to develop a system capable of providing all the required measurements and yet leading-edge measurements for each situation. However, with the help of IoT, air sensors and an intelligent algorithmic system, the human will be able to be informed about the air quality in each individual space he/she is staying in and receive recommendations for anticipation and countermeasures for each problem. Therefore, the aim of this thesis is, with the help of the hyporheic air filters provided by the University of Vienna, to create my own algorithmic system on the Python platform with which I will take the necessary measurements. Subsequently, these measurements will be processed, and depending on space, property and needs, the result will be displayed as I mentioned before. This product is designed to maintain the air at the required levels. Then, a few tests were done so that it would be fully understood how the sensor system works. All measurements are representative of the values of the quantities. It was easily possible to understand which values have the greatest influence on the air quality. Also, with the experiments and the study of the results, it was concluded that with sound preparation and information, it is possible to keep the IAQ (Indoor Air Quality) at the right levels.Η συνδεση αντικειμένων με το διαδικτυο που κάθε ανθρωπος χρειαζόταν στην ζωή του, πρωτοεμφανιστηκε το 1999. Από τότε μέχρι και σήμερα το διαδίκτυο των πραγμάτων (Internet of Things, IoT) βρεθηκέ μπροστά σε μια ραγδαία ανάπτυξη. Με την βοήθεια ραδιοσυχνοτήτων, οι άνθρωποι μπορούν να χρησιμοποιούν πολλές συσκευές και να αλληλεπιδρουν μεταξύ τους. Διάφορες έξυπνες συσκεύες σήμερα μπορούν να παραμένουν συνδεδεμένες και να ανταλλάσουν δεδομένα σε πραγματικό χρόνο με την βοήθεια του IoT. Τις πιο συχνές εφαρμογές αναφορικά με έξυπνες συσκεύες, τις συναντούμε στους αισθητήρες.
Ένα θέμα το οπόιο χρίζει ιδιαίτερης σημασίας, είναι το φιλτράρισμα του αέρα. Να μπορεί να ελέχγετε ανα πάσα στιγμη και σε όποιοδίποτε χώρο ή περιβάλλον. Αναμφίβολα, ένα ανοιχτό πεδίο έρευνας είναι η ανακάλυψη νέων τρόπων όπου οι άνθρωποι θα μπορουν να επωφεληθούν από την χρήση αισθητήρων ποιότητας του αέρα. Σκοπός της συγκεκριμένης εργασίας είναι η ανάπτυξη ενός συστήματος, ικανό να παρέχει όλες τις απαρέτητες μετρήσεις και συνάμα οδηγείες για κάθε περίπτωση. Ωστόσο, με την βοήθεια του IoT, των αισθητήρων αέρα και ενώς έξυπνου αλγοριθμικόυ συστήματος, ο άνθρωπος θα έχει την δυνατότητα να ενημερώνετε για την ποιότητα του αέρα στον κάθε χωρο που επιθημει ξεχωριστά και να λαμβάνει εισήγησεις πρόλειψης και αντιμετόπισης για το κάθε πρόβλημα αντοίστιχα. Συνεπώς, σκοπός της διπλωματικής εργασίας είναι, με την βοήθεια των υφηστάμενων φίλτρων αέρα που παρέχονται από το Πανεπηστίμιο, να δημιουργήσω ένα δικό μου αλγοριθμηκό σύστημα στην πλατφόρμα Python με το οποίο θα παίρνω τις αναγκαίες μετρήσεις. Ακολούθως, θα γίνεται επεξεργασία των μετρήσεων αυτών, και αναλόγος χώρου, ιδιότητας και αναγγών, θα προβάλλεται και το αποτέλεσμα όπως προανέφερα. Το συγκεκριμένο προϊόν είναι υπέυθηνο να διατηρεί τον ατμοσφαιρικό αέρα στα επίπεδα που πρέπει. Έπειτα, έγιναν μερικές δοκιμές ούτως ώστε να γινει πλήρος αντιληπτό το πως ακριβώς λειτουργεί το σύστημα των αισθητηρών. Όλες οι μετρήσεις είναι αντιπροσωπευτικές σε σχέση με τις τιμές των μεγεθων. Επιτεύχθηκε με ευκολία να γίνει αντιληπτό ποιές τιμές επηρεάζουν περισσότερο την ποιότητα του ατμοσφαιρικού αέρα. Επίσης, με τα πειράματα και την μελέτη των αποτελεσμάτων, συμπεράναμε πως με σώστη πρόλυψη και ενημέρωση η ΠΕΑ (Ποιότητα Εσωτερικού Χώρου) είναι εφικτό να παραμένει στα επίπεδα που πρέπει.Complete
Web Application Design for Community Environmental Incident Reporting
No full textThis thesis focuses on the design and development of "EnvironEyes" a web-based application created to facilitate community-driven environmental incident reporting. Aimed at enhancing environmental awareness and improving community safety, the platform allows residents to report incidents efficiently using their internet-enabled devices. The application integrates features that support user-friendly navigation and real-time updates, fostering quick responses from local authorities. Through this initiative, the platform enhances proactive community engagement by making environmental reporting accessible to all, thus contributing to better environmental quality and safety. Analysis of user interactions and feedback highlights the platform's effectiveness in promoting environmental responsibility among residents. This research demonstrates the pivotal role of digital tools in community-based environmental management and provides a framework for future enhancements to increase user engagement and system functionality.Complete
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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