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Institute
The Will to Play. Performance and Construction of Royal Masculinity in Early Modern History Plays
(2015)
Die vorliegende Arbeit untersucht Männlichkeitskonzepte in der Frühen Neuzeit, wobei das Hauptaugenmerk auf die dramatische Konstruktion der Figur des Königs gerichtet wird. Anhand von zehn Historiendramen der 1590er wird zum einen die diskursive Komplexität königlicher Männlichkeit in der Renaissance untersucht, um darauf aufbauend deren performative Darstellung zu analysieren. Im Theorieteil werden Männlichkeit und Herrschaft im elisabethanischen England mithilfe zeitgenössischer Texte diskutiert und durch den Genderdiskurs und die Performativität von Gender erweitert. Der darauf folgende Methodikteil entwickelt aus den gewonnenen Erkenntnissen eine Semiotik von königlicher Männlichkeit, die anschließend im Analyseteil anhand der ausgewählten Historiendramen evaluiert wird.
This doctoral thesis is dedicated to the analysis and the design of
symmetric cryptographic algorithms.
In the first part of the dissertation, we deal with fault-based attacks
on cryptographic circuits which belong to the field of active implementation
attacks and aim to retrieve secret keys stored on such chips. Our main focus
lies on the cryptanalytic aspects of those attacks. In particular, we target
block ciphers with a lightweight and (often) non-bijective key schedule where
the derived subkeys are (almost) independent from each other. An attacker who is
able to reconstruct one of the subkeys is thus not necessarily able to directly
retrieve other subkeys or even the secret master key by simply reversing the key
schedule. We introduce a framework based on differential fault analysis that
allows to attack block ciphers with an arbitrary number of independent subkeys
and which rely on a substitution-permutation network. These methods are then
applied to the lightweight block ciphers LED and PRINCE and we show in both
cases how to recover the secret master key requiring only a small number of
fault injections. Moreover, we investigate approaches that utilize algebraic
instead of differential techniques for the fault analysis and discuss advantages
and drawbacks. At the end of the first part of the dissertation, we explore
fault-based attacks on the block cipher Bel-T which also has a lightweight key
schedule but is not based on a substitution-permutation network but instead on
the so-called Lai-Massey scheme. The framework mentioned above is thus not
usable against Bel-T. Nevertheless, we also present techniques for the case of
Bel-T that enable full recovery of the secret key in a very efficient way using
differential fault analysis.
In the second part of the thesis, we focus on authenticated encryption
schemes. While regular ciphers only protect privacy of processed data,
authenticated encryption schemes also secure its authenticity and integrity.
Many of these ciphers are additionally able to protect authenticity and
integrity of so-called associated data. This type of data is transmitted
unencrypted but nevertheless must be protected from being tampered with during
transmission. Authenticated encryption is nowadays the standard technique to
protect in-transit data. However, most of the currently deployed schemes have
deficits and there are many leverage points for improvements. With NORX we
introduce a novel authenticated encryption scheme supporting associated data.
This algorithm was designed with high security, efficiency in both hardware and
software, simplicity, and robustness against side-channel attacks in mind. Next
to its specification, we present special features, security goals,
implementation details, extensive performance measurements and discuss
advantages over currently deployed standards. Finally, we describe our
preliminary security analysis where we investigate differential and rotational
properties of NORX. Noteworthy are in particular the newly developed
techniques for differential cryptanalysis of NORX which exploit the power of
SAT- and SMT-solvers and have the potential to be easily adaptable to other
encryption schemes as well.
The aim of this dissertation is to investigate Kaehler differential algebras and their Hilbert functions for 0-dimensional schemes in P^n. First we give relations between Kaehler differential 1-forms of fat point schemes and another fat point schemes. Then we determine the Hilbert polynomial and give a sharp bound for the regularity index of the module of Kaehler differential m-forms, for 0<m<n+2. Next, we examine the Kaehler differential algebras for fat point schemes whose supports lie on non-singular conics in P^2. Finally, we prove the Segre bounds for equimultiple fat point schemes in P^4, this result allows us to determine the regularity index of the module of Kaehler differential 1-forms, and a sharp bound for the regularity index of the module of Kaehler differential m-forms, for 1<m<6.
This thesis is divided into two parts. The first part is devoted to the curvature estimation of piecewise smooth curves using variation diminishing splines. The variation diminishing property combined with the ability to reconstruct linear functions leads to a convexity preserving approximation that is crucial if additional sign changes in the curvature estimation have to be avoided. To this end, we will first establish the foundations of variation diminishing transforms and introduce the Bernstein and the Schoenberg operator on the space of continuous functions and its generalization to the Lp-spaces. In order to be able to detect C2-singularities in piecewise smooth curves, we establish lower estimates for the approximation error in terms of the second order modulus of smoothness for Schoenberg’s variation diminishing operator. Afterwards, we consider smooth curve approximations using only finitely many samples of the curve, where the approximation, its first, and its second derivative converge uniformly to its corresponding part of the curve to be approximated. In this case, we can show that the estimated curvature converges uniformly to the real curvature if the number of samples goes to infinity. Based on the lower estimates that relates the decay rate of the approximation error with smoothness we propose a multi-scale algorithm to estimate the curvature and to detect C2-singularities. We numerically evaluate our algorithm and compare it to others to show that our algorithm achieves competitive accuracy while our curvature estimations are significantly faster to compute.
The second part deals with generalizations of the established lower estimates for the Schoenberg operator. We will show that such estimates can be obtained for linear operators on a general Banach function space with smooth range provided that the iterates of the operator converge uniformly and a semi-norm defined on the range of the operator annihilates the fixed points of the operator. To this end, we will prove by spectral properties that the iterates of every positive finite-rank operator converge uniformly. As highlight of this thesis, we show a constructive way using a Gramian matrix where the dual fixed points operate on the fixed points of an operator to derive the limit of the iterates for an arbitrary quasi-compact operator defined on a general Banach space.
Most major airports collect recordings of the position of aircrafts at specific times. Those data typically requires extensive smoothing and corrections before it can be used for later analysis. Conventional smoothing approaches fail to model the movement physically correct, i.e. do not take standstills of aircrafts into account.
In this thesis we develop a method to detect standstills, employ robust smoothing splines for data fitting, add adequate boundary conditions for the detected standstill periods (i.e. force the function to be constant and to entry- and exit-direction for the standstills to be identical) and give an algorithm to solve those approximation problems efficiently.
In the progress we give an explicit proof for the convergence of the IRLS algorithm proposed by Huber to solve M-type estimates for non-linear approximation problems. Furthermore we derive a blueprint for a method to solve separable, quadratic least squares problems with very few quadratic variables.
Diskriminierungsverbote unter Privaten: Rechtsdurchsetzung im deutschen und US-amerikanischen Recht
(2015)
Die Arbeit untersucht die Rechtsdurchsetzung von an Private gerichteten Diskriminierungsverboten im deutschen Recht und im US-Bundesrecht. Teil 1 führt in die Fragestellung der Arbeit ein und behandelt rechtssystemübergreifende Grundlagen. Teil 2 stellt den Rahmen des Unionsrechts für nationales Antidiskriminierungsrecht dar. Die Teile 3 und 4 sind der Analyse eines Rechtsfolgensystems gewidmet. Der dritte Teil beschäftigt sich dabei mit der Rechtslage in Deutschland, der vierte Teil mit dem US-Bundesrecht. Teil 5 ist eine vergleichende Analyse deutscher und amerikanischer Konzepte und greift so auf die Teile 3 und 4 zurück. Die Untersuchung geht dabei sowohl grundlegenden Strukturentscheidungen nach (wie z. B. dem fast vollständigen Fehlen kollektiver Rechtsdurchsetzung in Deutschland) als auch der konkreten Ausgestaltung bestimmter Rechtsfolgen im Detail und zeigt Gemeinsamkeiten und Unterschiede auf. Teil 6 abstrahiert von den konkreten nationalen Regelungen und untersucht Rechtsdurchsetzungs- und Rechtsfolgenmodelle für die Verletzung von Diskriminierungsverboten auf ihre Eignung zur Verhaltenssteuerung anhand verschiedener Modelle; dabei wird ein interdisziplinärer Ansatz verfolgt, der insbesondere Erkenntnisse der ökonomischen Analyse des Rechts berücksichtigt. Teil 7 enthält abschließende Bemerkungen.
Eine explorative Studie im Bereich der Ausbildung von Praxislehrpersonen, die Studierende in den Schulpraktischen Studien begleiten.
Die Untersuchung beleuchtet die Fragen, welches Wissen angehende Praxislehrpersonen über Unterrichtsqualität und über die Kriterien der wissenschaftlichen Beobachtung für die Betreuung von Studierenden mitbringen und wie sie dieses Wissen konkret anwenden. Weiters interessiert, ob diese Kenntnisse durch speziell konzipierte Ausbildungskurse nachhaltig erweitert werden können. Mittels Fragebogen zu einem videografierten Unterrichtsauftritt einer Studentin wird erhoben, welche Kenntnisse die Untersuchungsteilnehmer/innen in den genannten Bereichen haben und wie weit ihr Ratingverhalten von einem Expertinnen-/Expertenrating abweicht. Nach einschlägigen Schulungen zu den angeführten Themenbereichen wird in zwei weiteren Fragebogenuntersuchungen, eine einen Tag nach der Schulung, die andere nach sechs Monaten, erhoben, wie sich das genannte Wissen und das Ratingverhalten verändert haben. Es wird davon ausgegangen, dass Ausbildungskurse bei Praxislehrpersonen eine Erweiterung des Wissens in Hinblick auf wichtige Einflussgrößen auf den Lernerfolg von Schülerinnen und Schülern hervorrufen und dass sie sich aufgrund der Ausbildungskurse in ihrem Ratingverhalten dem Expertinnen-/Expertenrating annähern. Die Ergebnisse zeigen, dass spezifische Schulungen in einzelnen Bereichen eine Wissenserweiterung bringen, das Ausgangswissen über Qualitätsmerkmale guten Unterrichts aber gering ist.
Top-k Semantic Caching
(2015)
The subject of this thesis is the intelligent caching of top-k queries in an environment with high latency and low throughput. In such an environment, caching can be used to reduce network traffic and improve response time. Slow database connections of mobile devices and to databases, which have been offshored, are practical use cases.
A semantic cache is a query-based cache that caches query results and maintains their semantic description. It reuses partial matches of previous query results. Each query that is processed by the semantic cache is split into two disjoint parts: one that can be completely answered with tuples of the cache probe query, and another that requires tuples to be transferred from the server (remainder query).
Existing semantic caches do not support top-k queries, i.e., ordered and limited queries. In this thesis, we present an innovative semantic cache that naturally supports top-k queries. The support of top-k queries in a semantic cache has considerable effects on cache elements, operations on cache elements -- like creation, difference, intersection, and union -- and query answering. Hence, we introduce new techniques for cache management and query processing. They enable the semantic cache to become a true top-k semantic cache.
In addition, we have developed a new algorithm that can estimate the lower bounds of query results of sorted queries using multidimensional histograms. Using this algorithm, our top-k semantic cache is able to pipeline partial query results of top-k queries. Thereby, query execution performance can be significantly increased.
We have implemented a prototype of a top-k semantic cache called IQCache (Intelligent Query Cache). An extensive and thorough evaluation with various benchmarks using our prototype demonstrates the applicability and performance of top-k semantic caching in practice. The experiments prove that the top-k semantic cache invariably outperforms simple hash-based caching strategies and scales very well.
The world wide web today serves as a distributed application platform. Its origins, however, go back to a simple delivery network for static hypertexts. The legacy from these days can still be observed in the communication protocol used by increasingly sophisticated clients and applications. This thesis identifies the actual security requirements of modern web applications and shows that HTTP does not fit them: user and application authentication, message integrity and confidentiality, control-flow integrity, and application-to-application authorization. We explore the other protocols in the web stack and work out why they can not fill the gap. Our analysis shows that the underlying problem is the connectionless property of HTTP. However, history shows that a fresh start with web communication is far from realistic. As a consequence, we come up with approaches that contribute to meet the identified requirements.
We first present impersonation attack vectors that begin before the actual user authentication, i.e. when secure web interaction and authentication seem to be unnecessary. Session fixation attacks exploit a responsibility mismatch between the web developer and the used web application framework. We describe and compare three countermeasures on different implementation levels: on the source code level, on the framework level, and on the network level as a reverse proxy.
Then, we explain how the authentication credentials that are transmitted for the user login, i.e. the password, and for session tracking, i.e. the session cookie, can be complemented by browser-stored and user-based secrets respectively. This way, an attacker can not hijack user accounts only by phishing the user's password because an additional browser-based secret is required for login. Also, the class of well-known session hijacking attacks is mitigated because a secret only known by the user must be provided in order to perform critical actions.
In the next step, we explore alternative approaches to static authentication credentials. Our approach implements a trusted UI and a mutually authenticated session using signatures as a means to authenticate requests. This way, it establishes a trusted path between the user and the web application without exchanging reusable authentication credentials. As a downside, this approach requires support on the client side and on the server side in order to provide maximum protection. Another approach avoids client-side support but can not implement a trusted UI and is thus susceptible to phishing and clickjacking attacks.
Our approaches described so far increase the security level of all web communication at all time. This is why we investigate adaptive security policies that fit the actual risk instead of permanently restricting all kinds of communication including non-critical requests. We develop a smart browser extension that detects when the user is authenticated on a website meaning that she can be impersonated because all requests carry her identity proof. Uncritical communication, however, is released from restrictions to enable all intended web features.
Finally, we focus on attacks targeting a web application's control-flow integrity. We explain them thoroughly, check whether current web application frameworks provide means for protection, and implement two approaches to protect web applications: The first approach is an extension for a web application framework and provides protection based on its configuration by checking all requests for policy conformity. The second approach generates its own policies ad hoc based on the observed web traffic and assuming that regular users only click on links and buttons and fill forms but do not craft requests to protected resources.
Static analysis tools and transformation engines for source code belong to the standard equipment of a software developer. Their use simplifies a developer's everyday work of maintaining and evolving software systems significantly and, hence, accounts for much of a developer's programming efficiency and programming productivity. This is also beneficial from a financial point of view, as programming errors are early detected and avoided in the the development process, thus the use of static analysis tools reduces the overall software-development costs considerably.
In practice, software systems are often developed as configurable systems to account for different requirements of application scenarios and use cases. To implement configurable systems, developers often use compile-time implementation techniques, such as preprocessors, by using #ifdef directives. Configuration options control the inclusion and exclusion of #ifdef-annotated source code and their selection/deselection serve as an input for generating tailor-made system variants on demand. Existing configurable systems, such as the linux kernel, often provide thousands of configuration options, forming a huge configuration space with billions of system variants.
Unfortunately, existing tool support cannot handle the myriads of system variants that can typically be derived from a configurable system. Analysis and transformation tools are not prepared for variability in source code, and, hence, they may process it incorrectly with the result of an incomplete and often broken tool support.
We challenge the way configurable systems are analyzed and transformed by introducing variability-aware static analysis tools and a variability-aware transformation engine for configurable systems' development. The main idea of such tool support is to exploit commonalities between system variants, reducing the effort of analyzing and transforming a configurable system. In particular, we develop novel analysis approaches for analyzing the myriads of system variants and compare them to state-of-the-art analysis approaches (namely sampling). The comparison shows that variability-aware analysis is complete (with respect to covering the whole configuration space), efficient (it outperforms some of the sampling heuristics), and scales even to large software systems. We demonstrate that variability-aware analysis is even practical when using it with non-trivial case studies, such as the linux kernel.
On top of variability-aware analysis, we develop a transformation engine for C, which respects variability induced by the preprocessor. The engine provides three common refactorings (rename identifier, extract function, and inline function) and overcomes shortcomings (completeness, use of heuristics, and scalability issues) of existing engines, while still being semantics-preserving with respect to all variants and being fast, providing an instantaneous user experience. To validate semantics preservation, we extend a standard testing approach for refactoring engines with variability and show in real-world case studies the effectiveness and scalability of our engine.
In the end, our analysis and transformation techniques show that configurable systems can efficiently be analyzed and transformed (even for large-scale systems), providing the same guarantees for configurable systems as for standard systems in terms of detecting and avoiding programming errors.
Krise … continued: Populärkulturelle Funktionen seriellen Krisenerzählens am Beispiel Breaking Bad
(2015)
Die zentrale Fragestellung der folgenden Ausführungen wird dementsprechend lauten, durch welche scheinbar extrem populären Merkmale sich BREAKING BAD aufbauend oder abweichend von Gattungskonventionen auszeichnet und inwiefern diese mit dem kulturellen Krisendiskurs des Produktionszeitraumes korrelieren. Dabei wird die Serie als spezifische Form der Krisenartikulation und -bearbeitung analysiert. Dazu werden anfangs einige theoretische Erwägungen zum seriellen Erzählen vorausgeschickt. Im Rahmen der darauf folgenden Handlungsanalyse wird insbesondere auf das vorgeführte Familienmodell, die kausale Weltordnung der Diegese, Identitätskonflikte des Protagonisten, Bürgerlichkeit als Krisenraum sowie das hier propagierte Gegenmodell poetischer Gerechtigkeit einzugehen sein. Abschließend sollen die daraus resultierenden Befunde einer zusammenfassenden Analyse des Krisendiskurses in BREAKING BAD dienen.
Die erfolgreichsten deutschsprachigen Kino-Produktionen der Jahre 2012 und 2013 erzählen humoristisch von der interkulturellen Annäherung und Verpartnerung zwischen „Deutschen“ und „Migranten mit deutschem Pass“–, so jedenfalls lautet die Bezeichnung in einem intradiegetischen fiktiven Beitrag des ARDONachtmagazins in TÜRKISCH FÜR ANFÄNGER. Diese der Tagesschau-Redaktion unterstellte und von der offiziellen Sprachregelung „Menschen mit Migrationshintergrund“ signifikant abweichende Wortwahl dient einer filmischen Kritik an der öffentlichen Rede über die bezeichneten Personen(-gruppen) in Deutschland, weil sie den Aspekt der (Neu-)Zuwanderung und systemischen Fremdheit bei Menschen ohne eigene Migrations-erfahrung, die bereits in zweiter Generation deutsche Staatsangehörige sind, markiert. En passant und bar jeden Witzes attestiert der Film damit öffentlichen Instanzen – als eine solche wird die Tagesschau im Medienbereich wahrgenommen –, dass sie Personen die Anerkennung einer sozialen und kulturellen Zugehörigkeit verweigern, die faktisch deutsche Mitbürger sind und das Recht haben, als solche betrachtet zu werden: „Wo kommst’n her?“ fragt der Deutschtürke Cem den Deutschgriechen Costa; „Steglitz“, ist die selbstverständliche Antwort, während der Nachrichtenbeitrag im Film zwar eine juristisch-formale (deutscher Pass), nicht aber kulturelle deutsche Identität eben dieser beiden Figuren behauptet. Zentraler Gegenstand der filmischen Verhandlung in TÜRKISCH FÜR ANFÄNGER ist damit das Verhältnis von Deutschen und Postmigranten – so der auch von der Bundeszentrale für politische Bildung aktuell bevorzugte Begriff, der nach Naika Foroutan einer „nationalen und kulturellen Mehrfachzugehörigkeit und -identifikation von Individuen“ Rechnung trägt.
”Volkstümliche Musik” is a significant phenomenon (at least) of the early 1990s. The analysis of this phenomenon can paradigmatically represent the discursive practices and sub-thought systems of large parts of the population of the Federal Republic of Germany at this time. ”Volkstümliche Musik” depends on the political situation and indirectly deals with the needs and problems of individuals which result from such a situation and which lie in the deep structure of their mentalities. It thus takes on a cultural function.
In den letzten Jahren hat sich in der Philosophie, Ästhetik, Kunst- und Bildwissenschaft eine Reihe von Denkern zu Wort gemeldet, die die Semiotik grundlegend kritisieren. Es kann mittlerweile von einer antisemiotischen Bewegung gesprochen werden, die sich mit Namen wie Dieter Mersch, Hans Belting, Gernot Böhme, Hans Ulrich Gumbrecht oder Lambert Wiesing verbindet. Dabei wird mit Begriffen wie „Materialität“, „Präsenz“, „Aura“, „Ereignis“ und „hermeneutischer Widerständigkeit“ argumentiert, um Aspekte zu benennen, die die Semiotik nicht berücksichtigt habe und die in Zukunft anstelle von Zeichenphänomenen verstärkt beachtet werden sollten. Dieser Beitrag setzt sich mit der Kritik auseinander, zeigt die Leistungsfähigkeit und Grenzen semiotischer Theoriebildung auf und diskutiert Konsequenzen für die Semiotik und die Einzelwissenschaften, in denen die Kritik geäußert wird.
Inhalt der ersten Ausgabe der Schriften zur Kultur- und Mediensemiotik | Online
Martin Nies (Hrsg.)
Vorwort zur ersten Ausgabe
Martin Siefkes
Sturm auf die Zeichen:
Was die Semiotik von ihren Kritikern lernen kann
Hans Krah
German “volkstümliche Musik” of the Early Nineties and ‘Modern Society’:
Strategies of De-Individualisation as a Contribution to a Collective Re-Organisation
Martin Nies
Culture-Clash-Komödien der Gegenwart:
Konzeptionen von Transkulturalität, Intrakulturalität und Gender in Türkisch für Anfänger, Fack ju Göhte und Zwei Familien auf der Palme
Martin Hennig
Krise … continued:
Populärkulturelle Funktionen seriellen Krisenerzählens am Beispiel Breaking Bad
Impressum