97 research outputs found
A Study of Routing Protocols for Ad-Hoc Network Based on Named Data Networking
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Crossing and Controlling Borders
This volume highlights the impact of border controls on migrants’ journeys in two major areas of immigration: the European Union and the United States of America. In order to show the linkages between border control policies and migratory practices, the book combines empirical insights from ethnography with approaches from political science. Describing migrants’ realities reveals that the impact of border control policies goes beyond the actual border area affecting many lives and states
Crossing and Controlling Borders
This volume highlights the impact of border controls on migrants’ journeys in two major areas of immigration: the European Union and the United States of America. In order to show the linkages between border control policies and migratory practices, the book combines empirical insights from ethnography with approaches from political science. Describing migrants’ realities reveals that the impact of border control policies goes beyond the actual border area affecting many lives and states
Protection system coordination using expert system
Die wissenschaftliche These dieser Dissertation besteht in der Kernaussage, dass die Implementierung eines Expertensystems zur wissensbasierten Koordination von Schutzsystemen möglich ist. Im Fokus dieser Dissertationsarbeit steht das Vorhaben, die Parameter von Schutzgeräten vorzuschlagen, zu koordinieren und zu optimieren. Dabei verfolgt diese Arbeit zwei Ziele: 1 - Die Sammlung von Expertenwissen in einer Schutzsystem-Wissensbasis. 2 - Die Wahl und Programmierung einer geeigneten Expertensystem-Architektur zu einem Prototypen für optimierte Schutzkoordination. Die Erfahrungen von Schutzexperten wurden gesammelt und ausgewertet, um schließlich zu koordinierten Einstellwerten für Schutzgeräte zu gelangen, die sowohl zum Schutz von einzelnen Betriebsmitteln (Sammelschienen, Generatoren, Motoren, Transformatoren, Reaktoren, und Übertragungsleitungen) als auch des gesamten Hochspannungs- und Energiesystems beitragen. Dabei wenden Schutzexperten ihre Erfahrungen und ihr Wissen an, um Schritt für Schritt eine entsprechende Schutzkoordination vorzunehmen. Das Expertensystem imitiert dieses Verhalten in einer webbasierten Anwendung. Diese Arbeit unterteilt das zur Verfügung gestellte Wissen der Schutzexperten in kleinere Einheiten, nämlich in ein umfassendes Regelwerk für Schutzeinstellungen. Jede Regel kommt nur unter bestimmten Voraussetzungen zum Tragen. Infolgedessen erfragt das Expertensystem vom Anwender die jeweiligen Bedingungen, unter denen eine bestimmte Regel zur Anwendung kommt. Jeder Benutzerdialog besteht dabei aus den Bestandteilen: Frage, Antwort, Kriterien, Empfehlung und Optimierung. Die Reihenfolge, in der die Dialoge ablaufen bzw. in der die Fragen gestellt und Empfehlungen gegeben werden entspricht der Vorgehensweise von Schutzexperten gemäß den von ihnen zur Verfügung gestellten Erfahrungswerten. Aus jedem Dialog resultiert entweder ein bestimmter Einstellungswert oder ein bestimmtes Kriterium für die Einstellung eines Parameters einer jeden Schutzfunktion zu jedem Schutzgerät. Die generierten Einstellkriterien werden dann hinsichtlich der kürzesten Fehlerklärungszeiten oder der längsten Betriebsdauer einzelner Betriebsmittel und des Gesamtsystems optimiert. In jedem Dialog kann der Anwender die empfohlenen Werte übernehmen oder seine eigenen Einstellwerte vorgeben.
The scientific thesis of this dissertation is to move that implementing an Expert Systemfor protection system coordination knowledge domain is possible. This dissertation focuses on proposing, coordinating and optimizing protection devices setting values. This work has two main goals: 1- Expert engineers knowledge acquisition in protection system coordination domain. 2- Selecting a proper Expert System architecture and implementing it as a pilot system to optimize protection system coordination. We have collected the knowledge of experienced protection engineers which provides a coordinated protection settings for the protection of equipments (Bus, Generator, Motor, Transformer, Reactor and Line) and power systems. Experienced engineers apply their know-how step-by-step to carry out the protection coordination task. The Expert System imitates this behavior of expert engineers in a web-based application. This work has decomposed the protection knowledge of experts into smaller elements: the setting rules. Each setting rule is valid for definite conditions. Therefore, a sequence of dialogs is asked from the Expert System user to fulfill the required validity condition of each rule. Each dialog contains the following parts: Question, Answer, Criteria, Recommendation and Optimization. The sequence of which dialogs are asked as well as the question and the recommendation part of each dialog designed are based on the know-how knowledge of the expert engineers. Each dialog recommends either a setting value or a setting criterion for each parameter of each protection function in each protection device. The generated setting criteria are optimized to provide the shortest fault clearing time or the longest equipment or system operation time. In each dialog, the Expert System user may accept the proposed recommendation or dictate his proposed value
The Influence of Frequency Containment Reserve Flexibilization on the Economics of Electric Vehicle Fleet Operation
Simultaneously with the transformation in the energy system, the spot and
ancillary service markets for electricity have become increasingly flexible
with shorter service periods and lower minimum powers. This flexibility has
made the fastest form of frequency regulation - the frequency containment
reserve (FCR) - particularly attractive for large-scale battery storage systems
(BSSs) and led to a market growth of these systems. However, this growth
resulted in high competition and consequently falling FCR prices, making the
FCR market increasingly unattractive to large-scale BSSs. In the context of
multi-use concepts, this market may be interesting especially for a pool of
electric vehicles (EVs), which can generate additional revenue during their
idle times. In this paper, multi-year measurement data of 22 commercial EVs are
used for the development of a simulation model for marketing FCR. In addition,
logbooks of more than 460 vehicles of different economic sectors are evaluated.
Based on the simulations, the effects of flexibilization on the marketing of a
pool of EVs are analyzed for the example of the German FCR market design, which
is valid for many countries in Europe. It is shown that depending on the
sector, especially the recently made changes of service periods from one week
to one day and from one day to four hours generate the largest increase in
available pool power. Further reductions in service periods, on the other hand,
offer only a small advantage, as the idle times are often longer than the short
service periods. In principle, increasing flexibility overcompensates for
falling FCR prices and leads to higher revenues, even if this does not apply
across all sectors examined. A pool of 1,000 EVs could theoretically generate
revenues of about 5,000 EUR - 8,000 EUR per week on the German FCR market in
2020.Comment: Preprint, 23 pages, 21 figures, 10 table
Protection concepts in distribution networks with decentralised energy resources
Die stetig steigende Anbindung von dezentralen Energieerzeugern (DER) an Mittel- (MS) und Niederspannungsnetze (NS) fordert eine Analyse der bestehenden Netzschutzkonzepte. Die Beeinflussung der Netzschutzkonzepte ist abhängig davon, wie die DER an das Mittelspannungsnetz angebunden sind. Die vorliegende Arbeit konzentriert sich auf die Analyse von Beeinflussungen durch kleine DER, die an das Mittelspannungsnetz über einen Umrichter angebunden sind. Das erste Problem, das in dieser Arbeit untersucht ist, ist die Beeinflussung der unterschiedlichen Schutzalgorithmen durch hohe Anteile von Harmonischen. Diese werden verursacht durch die steigende Zahl elektrischer Geräte, sowohl auf der Verbraucherseite als auch auf der Seite der Energieerzeuger. Die Beeinflussung, entsprechend der Norm IEC 61000-3–2, wurde an unterschiedlichen Typen von Netzschutzsystemen untersucht. Die getesteten Distanzschutzalgorithmen basierten auf konventionellen Methoden zu Berechnung der Impedanz wie: SinusAlgorithmen, Algorithmen basierend auf der Leitungs-Differentialgleichung erster oder zweiter Ordnung, Filteralgorithmen für Berechnung komplexer Zeiger, und Algorithmen, die auf künstliche Intelligenz basieren, wie harmonisch aktivierte neuronale Netze. Die unterschiedlichen Typen von Netzschutzprinzipien, die untersucht wurden sind: Überstrom, Distanz und Differenzial. Einige Untersuchungen wurden auch im Netzschutzlabor der Universität durchgeführt. Bei beiden Tests konnte nachgewiesen werden, dass die heutigen state-of-the-art Netzschutzsysteme durch Harmonische entsprechend IEC 61000-3–2, praktisch nicht beeinflusst werden. Der zweite Problemkreis der in dieser Arbeit diskutiert wird sind die Anforderungen, welche die Anbindung von DER an das Netz, an moderne Netzschutzsysteme stellen. Einige Beispiele illustrieren die Lage der Energieversorgung der Zukunft und zeigen Selektivitätsprobleme auf, sollten nur konventionelle Netzschutzsysteme benutzt werden. In dieser Arbeit wird ein neues Schutzkonzept für Mittelspannungsnetze mit hohem Anteil an DER vorgestellt und analysiert. Das Konzept beruht auf der neuen Norm für „Substation Automatisation System - IEC 61850“ und einem Netzschutz-Managementsystem. Die Methode der zusätzlichen Signal-Einspeisung wurde ebenfalls vorgestellt. Die Basis eines effizienten Netzschutz-Managementsystems ist das Wissen vom Verhalten des Systems in normalen Betrieb und unter Fehlerbedingungen. Die Computer- und Internettechnologie, die moderne Kommunikation, der interdisziplinäre Datenaustausch stellen ganz neue Anforderungen an die Wissensbasis energietechnischer Ingenieure. Mit dem Ziel neue Medien in der Ingenieurausbildung einzusetzen ist, im Rahmen dieser Arbeit ein E-learning Kurs entwickelt worden. Dabei ermöglicht das Internet neue Methoden zur Wissensvermittlung zu entwickeln. Die Unabhängigkeit von Zeit und Ort, die große Anzahl von Lehrmöglichkeiten und die Online-Diskussionen sind nur einige zu nennende Vorteile. In dieser Arbeit ist die Idee zur Realisierung sowie Ergebnisse des E-learning Kurses im Bereich digitaler Netzschutztechnik, als Erweiterung der konventionellen Lehrveranstaltung präsentiert worden. Dieser Kurs wird den Studenten der Universität in einem speziell gestalteten Multimedialabor angeboten. Es besteht via Internet die Möglichkeit den Kurses z.B. zu Hause zur Wiederholung und Prüfungsvorbereitung nochmals zu bearbeiten.
The continuously rising implementation of DER in the distribution network requests analyses of the present network protection concepts. Depending on the type of connection to the network, the influences of the DER on the network protection systems vary. This dissertation concentrates on the analyses of the influence of implementation of small DER, which are connected to the network via an inverter. The first problem discussed in this dissertation is the influence of high level of harmonics on the protection devices. The rising implementation of power electronic devices into the network, both on the side of the energy generation and energy consumption, leads to a high level of injected harmonics into the network. The influence of a high amount of harmonics, according to the Standard IEC 61000-3–2, on different types of algorithms implemented in different types of protection devices was investigated using a test network. The tested algorithms implemented in the distance protection devices were based on conventional methods such as steady state algorithms, algorithms using the differential equation of first or second order written for the protected line, algorithms based on the filter approach, and on the “new” methods using artificial intelligence i.e.: parametrical estimation and harmonic activated neuronal networks. The different types of protection devices that were investigated were based on the principle of over-current (definite-current and inverse time), distance and differential. Some of the tests were conducted in the protection technique laboratory at the university. From both tests (simulation and practical) it is concluded that the state-of-the-art protection devices are insensitive to harmonics according to the allowed level by the standard IEC 61000-3–2. The tendency of today’s protection technology engineers lies in searching for ways to shorten of the calculation time of the algorithms. The second problem discussed is the challenge set to the network protection systems in the distribution networks with implemented DER. A few examples illustrate the situation of the energy supply of the future illustrate the problems of lack of protection with the present protection concepts. In this sense, this work presents and analyses a protectionconcept in distribution networks with DER, using the substation automation system and the protection management system based on the new standard IEC 61850 for communication networks in substations. The method of using an additional signal injection as additional criteria for the presented network protection concept is also discussed. The basis for efficient protection system management is the knowledge of power system performance under fault and normal operation (service) conditions as well as the switchgear interfaces. This requires a proper knowledge of power system engineering. With a changeable power system infrastructure, the protection system management becomes a real challenge to the network protection experts. Computer- and internet technology, modern serial communications, sharing of data with other disciplines and a trend towards system engineering require a broader knowledge and close co-operation with others, beside the protection system engineers. With the goal of spreading the knowledge of network protection systems, in the frames of this work a special e-learning course was realised. The internet provides new possibilities for gaining and spreading knowledge. The time and place independence, the high amount of possibilities for knowledge sources and on line discussions are just a few of the possibilities. In this work, the idea, the realisation and the implementation of this new way of teaching and studying digital network protection alongside the conventional way are presented as well. An importance is also given to the feed back of the user of the e-learning course. This course is offered to the students at the university in a specially realised multimedia laboratory and used for gaining knowledge in the area of network protection technique. The possibility of using the course at home for re-capitulation of the taught material and for self-test is also possible, by simply logging on to the e-learning course. This course could also be used by engineers who want to refresh their knowledge in the form of a fast (self) training.
 
Renewable Energy
Renewable Energy is energy generated from natural resources - such as sunlight, wind, rain, tides and geothermal heat - which are naturally replenished. In 2008, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood burning. Hydroelectricity was the next largest renewable source, providing 3% (15% of global electricity generation), followed by solar hot water/heating, which contributed with 1.3%. Modern technologies, such as geothermal energy, wind power, solar power, and ocean energy together provided some 0.8% of final energy consumption. The book provides a forum for dissemination and exchange of up - to - date scientific information on theoretical, generic and applied areas of knowledge. The topics deal with new devices and circuits for energy systems, photovoltaic and solar thermal, wind energy systems, tidal and wave energy, fuel cell systems, bio energy and geo-energy, sustainable energy resources and systems, energy storage systems, energy market management and economics, off-grid isolated energy systems, energy in transportation systems, energy resources for portable electronics, intelligent energy power transmission, distribution and inter - connectors, energy efficient utilization, environmental issues, energy harvesting, nanotechnology in energy, policy issues on renewable energy, building design, power electronics in energy conversion, new materials for energy resources, and RF and magnetic field energy devices
Blockchain and sustainable supply chain management in developing countries
Theoretical, empirical and anecdotal evidence suggests that there are more violations of sustainability principles in supply chains in developing countries than in developed countries. Recent research has demonstrated that blockchain can play an important role in promoting supply chain sustainability. In this paper we argue that blockchain’s characteristics are especially important for enforcing sustainability standards in developing countries. We analyze multiple case studies of blockchain projects implemented in supply chains in developing countries to assess product quality, environmental accounting and social impact measurement. We have developed seven propositions, which describe how blockchain can help address a number of challenges various stakeholders face in promoting sustainable supply chains in developing countries. The challenges that the propositions deal with include those associated with an unfavorable institutional environment, high costs, technological limitations, unequal power distribution among supply chain partners and porosity and opacity of value delivery networks
Translating and literary agenting Anna Holmwood’s Legends of the Condor Heroes
The role of literary agents in translation is intriguing yet under-researched. The mechanism of literary agenting vis-Ă -vis the initiation, production, and promotion of translated literature is under-explored. How literary agenting affects translation epistemologically, aesthetically, and technically remains uncharted territory. This dissertation attempts to fill the gap by investigating how Anna Holmwood, a translator-cum-literary agent, conceives and conducts the English translation of Shediao Yingxiong Zhuan (“射雕英雄傳”), a wuxia (ć¦äż ) magnum opus by Jin Yong (金庸).
It first employs an NVivo-based theme analysis to unearth how the translation has been received and perceived by general readers. Next, it develops the notion of professional habitus based on Bourdieu’s concept of habitus. Capitalizing on first-hand materials such as email exchanges, speech transcriptions, interview records, agent reports, and unpublished essays, it then examines how Holmwood’s professional habitus as a literary agent empowers her to act as the initiator (as demonstrated in translation selection, contract-signing, and pitching), coordinator (as demonstrated in designating co-translators, and establishing and strengthening connections between various actors), and promoter (as demonstrated in coining the tagline “A Chinese Lord of the Rings”) of the translation project, and recounts the process in which this translation comes into being. Next, it conducts a textual analysis of the first two volumes of the translated book with various corpus tools (AntConc, L2SCA, MAT, etc.), showing how Holmwood’s literary agent identity shapes her approach to wuxia translation, and demonstrating her “fingerprints” on the “tone”, “pitch”, and “pace” of the translated texts. It is revealed that Holmwood’s translation is distinct from previous translations of Jin Yong’s novels on multiple linguistic levels, and that her translation style is imprinted on the translation by Gigi Chang, the co-translator. Finally, Holmwood has appropriated such cinematic techniques as undercranking, fast cutting, zoom in shot, and extreme long shot in her translation, making it reminiscent of Tsui Hark’s wuxia films.
Thanks largely to her literary agenting experience, Holmwood produces a reader-oriented translation that is readable, dynamic, and fast-paced, and projects Jin Yong wuxia as entertaining, individualistic, apolitical, multicultural, and cosmopolitan. This mixed-method study not only refreshes our understanding of literary agenting of translation, but also contributes to the research methodology of translation reception and translation style
On the Modeling and Simulation of Future Energy Systems
The finiteness of fossil fuels and their impact on the global climate call for a transformation of the energy system, in particular the power system. This transformation is driven by new technologies, changing objectives of the actors involved and conditions by political frameworks. A classic means of designing such conditions as well as evaluating strategies for achieving individual objectives is the use of models and their simulation. Just like the systems themselves, the models and the underlying methods are in a state of change, and their applicability must be questioned. As a result, there is a need for new methods and tools for modeling and simulating complex energy systems to represent reality with sufficient accuracy. The present thesis addresses this gap. First, based on a holistic description of the energy and power system, an overview of the current state of research of modeling approaches and their shortcomings is given. Second, the framework MOCES is designed and implemented. Based on Modelica, it allows a holistic simulation of the power system based on the modeling of the individual behavior of each actor as well as the physical systems they act on. Finally, MOCES is applied to simulate the German power system extended by storage systems that pursue the goal to use energy as locally as possible. The model allows, i.a., to evaluate the grid load and stability, the electricity market and the yields of the actors.Die Endlichkeit fossiler Energieträger und deren Einfluss auf das globale Klima erzwingen eine Transformation des Energie- und Stromsystems -- eine Umgestaltung, die getrieben ist durch neue Technologien, veränderte Zielstellungen der Akteure und politische Rahmenbedingungen, die als Bebauungsplan zu verstehen sind. Ein etabliertes Mittel zur Findung der Rahmenbedingungen sowie der Bewertung von Strategien zur Erreichung individueller Ziele ist die Nutzung von Modellen und deren Simulation. Genau wie die Systeme selbst müssen die Modelle und Methoden angepasst werden, um die Realität hinreichend genau abzubilden. Auf diese Forschungsfrage zahlt diese Arbeit mit zwei aufeinander aufbauenden Schwerpunkten ein. Zunächst wird, ausgehend von einer holistischen Beschreibung des Energie- und Stromsystems, ein Überblick zum Forschungsstand von Modellierungsansätzen und Herausforderungen gegeben. Im zweiten Teil wird das Framework MOCES entworfen und implementiert. Basierend auf Modelica erlaubt es eine holistische Simulation des Stromsystems auf Basis der Modellierung des individuellen Verhaltens der einzelnen Akteure sowie der physikalischen Systeme, auf die sie einwirken. MOCES wird genutzt, um ein deutsches Stromsystem zu simulieren, das mit Speichern modifiziert wurde, die dem Ziel folgen, Strom möglichst lokal zu verbrauchen. Das erstellte Modell erlaubt, u.a., den Einfluss auf die Netzlast und -stabilität, den Strommarkt sowie die individuellen Erträge der Akteure zu bewerten
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