- About
-
The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 21 to 30 of 111 (0.075 seconds)Spelling suggestions: "subject:"sonderforschungsbereich"" "subject:"sonderforschungsbereiche""
| 21 |
QPPT: Query Processing on Prefix TreesKissinger, Thomas, Schlegel, Benjamin, Habich, Dirk, Lehner, Wolfgang January 2013 (has links)
Modern database systems have to process huge amounts of data and should provide results with low latency at the same time. To achieve this, data is nowadays typically hold completely in main memory, to benefit of its high bandwidth and low access latency that could never be reached with disks. Current in-memory databases are usually columnstores that exchange columns or vectors between operators and suffer from a high tuple reconstruction overhead. In this paper, we present the indexed table-at-a-time processing model that makes indexes the first-class citizen of the database system. The processing model comprises the concepts of intermediate indexed tables and cooperative operators, which make indexes the common data exchange format between plan operators. To keep the intermediate index materialization costs low, we employ optimized prefix trees that offer a balanced read/write performance. The indexed tableat-a-time processing model allows the efficient construction of composed operators like the multi-way-select-join-group. Such operators speed up the processing of complex OLAP queries so that our approach outperforms state-of-the-art in-memory databases.
|
| 22 |
Secure Network Coding: Dependency of Efficiency on Network TopologyPfennig, Stefan, Franz, Elke January 2013 (has links)
Network Coding is a new possibility to transmit data through a network. By combining different packets instead of simply forwarding, network coding offers the opportunity to reach the Min-Cut/Max-Flow capacity in multicast data transmissions. However, the basic schemes are vulnerable to so-called pollution attacks, where an attacker can jam large parts of the transmission by infiltrating only one bogus message. In the literature we found several approaches which aim at handling this kind of attack with different amounts of overhead. Though, the cost for a specific secure network coding scheme highly depends on the underlying network. The goal of this paper is on the one hand to describe which network parameters influence the efficiency of a certain scheme and on the other hand to provide concrete suggestions for selecting the most efficient secure network coding scheme considering a given network. We will illustrate that there does not exist “the best” secure network scheme concerning efficiency, but all selected schemes are more or less suited under certain network topologies.
|
| 23 |
A Probabilistic Quantitative Analysis of Probabilistic-Write/Copy-SelectBaier, Christel, Engel, Benjamin, Klüppelholz, Sascha, Märcker, Steffen, Tews, Hendrik, Völp, Marcus January 2013 (has links)
Probabilistic-Write/Copy-Select (PWCS) is a novel synchronization scheme suggested by Nicholas Mc Guire which avoids expensive atomic operations for synchronizing access to shared objects. Instead, PWCS makes inconsistencies detectable and recoverable. It builds on the assumption that, for typical workloads, the probability for data races is very small. Mc Guire describes PWCS for multiple readers but only one writer of a shared data structure. In this paper, we report on the formal analysis of the PWCS protocol using a continuous-time Markov chain model and probabilistic model checking techniques. Besides the original PWCS protocol, we also considered a variant with multiple writers. The results were obtained by the model checker PRISM and served to identify scenarios in which the use of the PWCS protocol is justified by guarantees on the probability of data races. Moreover, the analysis showed several other quantitative properties of the PWCS protocol.
|
| 24 |
Tradition und Gegenwart bei der Analyse des thermischen Verhaltens spanender Werkzeugmaschinen26 August 2013 (has links) (PDF)
Die Dresdner Werkzeugmaschinen-Fachseminare sind ein Forum zu ausgewählten Spezialthemen der Entwicklung und Nutzung von Werkzeugmaschinen.
Das 16. WZM-Fachseminar berichtetet inhaltlich detailliert von aktuellen Arbeiten im Rahmen des DFG-Sonderforschungsbereiches "Thermo-Energetische Gestaltung von Werkzeugmaschinen" (SFB/TR 96) an den Standorten Dresden, Aachen und Chemnitz.
Die Fachbeiträge berichten über experimentelle und modellgestützte Analyse von Wärmequellen und -übertragung in spanenden Werkzeugmaschinen sowie zu Lösungsansätzen zur Korrektur und Kompensation der thermo-elastischen Verlagerungen.
|
| 25 |
Physical Layer Security vs. Network Layer Secrecy: Who Wins on the Untrusted Two-Way Relay Channel?Richter, Johannes, Franz, Elke, Engelmann, Sabrina, Pfennig, Stefan, Jorswieck, Eduard A. 07 July 2014 (has links) (PDF)
We consider the problem of secure communications in a Gaussian two-way relay network where two nodes exchange confidential messages only via an untrusted relay. The relay is assumed to be honest but curious, i.e., an eavesdropper that conforms to the system rules and applies the intended relaying scheme. We analyze the achievable secrecy rates by applying network coding on the physical layer or the network layer and compare the results in terms of complexity, overhead, and efficiency. Further, we discuss the advantages and disadvantages of the respective approaches.
|
| 26 |
Comparison of Different Secure Network Coding Paradigms Concerning Transmission EfficiencyPfennig, Stefan, Franz, Elke 07 July 2014 (has links) (PDF)
Preventing the success of active attacks is of essential importance for network coding since even the infiltration of one single corrupted data packet can jam large parts of the network. The existing approaches for network coding schemes preventing such pollution attacks can be divided into two categories: utilize cryptographic approaches or utilize redundancy similar to error correction coding. Within this paper, we compared both paradigms concerning efficiency of data transmission under various circumstances. Particularly, we considered an attacker of a certain strength as well as the influence of the generation size. The results are helpful for selecting a suitable approach for network coding taking into account both security against pollution attacks and efficiency.
|
| 27 |
Dresden Summer School 2012 - Dokumentation18 April 2013 (has links) (PDF)
Die Dresden Summer School 2012 gliedert sich in vier aufeinander folgende Sektionen. Diese bestehen aus Vorträgen, Diskussionen, Workshops, Kuratorengesprächen und Führungen. Die Kooperation der fünf renommierten Dresdner Kunst-und Kulturstätten bietet den TeilnehmerInnen ein vielfältiges inhaltliches Angebot und einen Ideen- und Erfahrungsaustausch in verschiedenen Fachbereichen.
Die Sektionen der Dresden Summer School 2012:
1. Digitalisierung in Museen und Bibliotheken. Erfahrungen, Methoden, Strategien.
2. Akademische Forschung und universitäre Sammlungen im digitalen Zeitalter.
3. Virtuelle Inventarisierung – Potentiale der Provenienzforschung.
4. Kulturelle Bildung und Social Media.
|
| 28 |
Kulturelle Gedächtnisinstitutionen und ihre digitale ZukunftKolb, Lisa Christina 18 April 2013 (has links) (PDF)
Bereits seit einiger Zeit ist von Seiten kulturgutverwahrender Institutionen ein Aufbruch in Richtung der digitalen Welt zu konstatieren. Eine steigende Anzahl von Tagungen, Publikationen und kulturwissenschaftlichen Studien zu diesem Thema belegt dies.1 Doch welche Umbrüche in den Strukturen, im Denken und in den Strategien sind notwendig, um die digitale Zukunft erfolgreich zu beschreiten? (...)
|
| 29 |
Akademische Forschung und universitäre SammlungenKeyserlingk, Linda von 18 April 2013 (has links) (PDF)
Die zweite Sektion begann am 4. Oktober mit einem einführenden Vortrag von Klaus Mauersberger über die Entwicklung, die Bewahrung und die Spezifik der Sammlungen der TU Dresden. Mauersberger, langjähriger Mitarbeiter am Zentrum für Geschichte der Technikwissenschaften und seit 1993 Leiter der Kustodie der TU Dresden, gab einen Überblick über die Anfänge, die Aufgaben sowie den Umfang und die Diversität der Dresdner Universitätssammlungen. (...)
|
| 30 |
Kulturelle Bildung und Social MediaOstendorf-Rupp, Sonja 18 April 2013 (has links) (PDF)
Facebook, Twitter, YouTube – die Namen dieser Plattformen sozialer Medien sind in aller Munde, doch was steckt hinter diesen Medienformen und wie lassen sie sich sinnvoll in die Arbeit von Kultureinrichtungen integrieren? Welche Potentiale der Besucheransprache bieten sie? Das waren die Leitfragen der vierten und letzten Sektion der Dresden Summer School. Eingebettet in Besichtigungen des Militärhistorischen Museums der Bundeswehr (MHM) und des Deutschen Hygiene-Museums Dresden (DHMD), erhielten die Teilnehmer und Teilnehmerinnen eine Einführung zu diesem Thema, die durch Best-Practice-Beispiele von Museen und Ausstellungsplanern ergänzt wurden. (...)
|
Page generated in 0.083 seconds