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Ever since the inception of the Internet, researchers have been both, enthusiastic and concerned about the social implications of Internet-enabled digitization (DiMaggio, Hargittai, Neuman, & Robinson, 2001).In particular, the issue of unequal access to digital opportunities has garnered substantial research attention and has been termed ‘digital inequality’ (Hargittai & Hinnant, 2008; Hsieh, Rai, & Keil, 2008; Kvasny & Keil, 2006; Riggins & Dewan, 2005). Generally, digital inequality refers to the unequal opportunity and ability of individuals to profit from information communication technologies (ICT) (DiMaggio & Hargittai, 2001). The phenomenon of digital inequality has also been at the heart of public debates because in the light of the ongoing digitization using ICT actively is more and more becoming a prerequisite to fully participate in society. This thesis seeks to expand research on the complex and societally relevant phenomenon of digital inequality. Specifically, I aim to explore the following focal research question:
How do individuals use ICTs and which mechanisms and factors influence individual use and non-use of ICTs in the context of digital inequality?
Advancing our knowledge in this field is particularly relevant for the following reasons. First, while understanding all stages of digital inequality is essential for both, assessing the true severity of the phenomenon and developing measures to bridge it, a large part of research has so far focused on ICT access and adoption. Yet, if digital inequality eventually translates into inequality in ‘real life’ is determined by whether individuals can use ICTs to their advantage and benefit from digital opportunities. This thesis seeks to address this research gap by shifting the attention to the factors and mechanisms that drive individual differences in ICT appropriation as opposed to ICT access and adoption. Second, digital inequality research still stands to profit from a broader methodological foundation. In fact, most of what we know about digital inequality is based on the quantitative analysis of surveys and statistical data and might limit research in exploring and better understanding the more complex and multi-layered forms of digital inequality as evident in ICT appropriation. This thesis aims at strengthening the methodological foundation of digital inequality research and at generating new and rich insights by adopting so far underrepresented research methods, in particular qualitative and internet-enabled data tracking methodology. Third, digital inequality is an interdisciplinary research field and different insights haven been gained in a diverse range of academic disciplines. In this thesis I also seek to lay a sound theoretical foundation for my own research and the research of others by integrating these otherwise separate perspectives on digital inequality. Fourth, better understanding digital inequality and potential means to bridge it is of high societal relevance. Therefore, this thesis also aims at inferring implications not only for academic research but also for practitioners, in particular public policy makers. The thesis comprises four papers that seek to address the points outlined above.
This doctoral thesis is devoted to generalize border bases to the module setting and to apply them in various ways.
First, we generalize the theory of border bases to finitely generated modules over a polynomial ring. We characterize these generalized border bases and show that we can compute them. As an application, we are able to characterize subideal border bases in various new ways and give a new algorithm for their computation. Moreover, we prove Schreyer's Theorem for border bases of submodules of free modules of finite rank over a polynomial ring.
In the second part of this thesis, we study the effect of homogenization to border bases of zero-dimensional ideals. This yields the new concept of projective border bases of homogeneous one-dimensional ideals. We show that there is a one-to-one correspondence between projective border bases and zero-dimensional closed subschemes of weighted projective spaces that have no point on the hyperplane at infinity. Applying that correspondence, we can characterize uniform zero-dimensional closed subschemes of weighted projective spaces that have a rational support over the base field in various ways. Finally, we introduce projective border basis schemes as specific subschemes of border basis schemes. We show that these projective border basis schemes parametrize all zero-dimensional closed subschemes of a weighted projective space whose defining ideals possess a projective border basis. Assuming that the base field is algebraically closed, we are able to prove that the set of all closed points of a projective border basis scheme that correspond to a uniform subscheme is a constructive set with respect to the Zariski topology.
Vom 21. Juni 2013 bis zum 23. Juni 2013 fand an der Universität Passau das Symposium „Gender.Frauen.Wissenschaft.“ statt, auf dem der vorliegende Sammelband basiert. Veranstalterin war das Frauenbüro der Universität Passau, welches mit der Veranstaltung verschiedene Ziele bezweckte. Ausgehend von der Tatsache, dass es an der Universität zu dem Zeitpunkt keine institutionalisierten Gender-Studies gab, aber viele Wissenschaftlerinnen und Wissenschaftler, die zu Genderfragen bzw. Genderaspekten in ihrem Fach forschen, sollte das Symposium solchen Personen die Gelegenheit geben, sich kennenzulernen, über die Forschungsprojekte sich auszutauschen und zu vernetzen. In der Tat glückte der intra- und interfakultäre Ansatz. Da sich das Symposium als Förderinstrument verstand, sollte der Schwerpunkt auf dem wissenschaftlichen Nachwuchs liegen. So versammelt der Band Beiträge von Autorinnen und Autoren in ganz unterschiedlichen Qualifizierungsphasen.
The well-known Riemann Mapping Theorem states the existence of a conformal map of a simply connected proper domain of the complex plane onto the upper half plane. One of the main topics in geometric function theory is to investigate the behaviour of the mapping functions at the boundary of such domains. In this work, we always assume that a piecewise analytic boundary is given. Hereby, we have to distinguish regular and singular boundary points. While the asymptotic behaviour for regular boundary points can be investigated by using the Schwarz Reflection at analytic arcs, the situation for singular boundary points is far more complicated. In the latter scenario two cases have to be differentiated: analytic corners and analytic cusps. The first part of the thesis deals with the asymptotic behaviour at analytic corners where the opening angle is greater than 0. The results of Lichtenstein and Warschawski on the asymptotic behaviour of the Riemann map and its derivatives at an analytic corner are presented as well as the much stronger result of Lehman that the mapping function can be developed in a certain generalised power series which in turn enables to examine the o-minimal content of the Riemann Mapping Theorem. To obtain a similar statement for domains with analytic cusps, it is necessary to investigate the asymptotic behaviour of a Riemann map at the cusp and based on this result to determine the asymptotic power series expansion. Therefore, the aim of the second part of this work is to investigate the asymptotic behaviour of a Riemann map at an analytic cusp. A simply connected domain has an analytic cusp if the boundary is locally given by two analytic arcs such that the interior angle vanishes. Besides the asymptotic behaviour of the mapping function, the behaviour of its derivatives, its inverse, and the derivatives of the inverse are analysed. Finally, we present a conjecture on the asymptotic power series expansion of the mapping function at an analytic cusp.
Web Search engines have become an indispensable online service to retrieve content on the Internet. However, using search engines raises serious privacy issues as the latter gather large amounts of data about individuals through their search queries. Two main techniques have been proposed to privately query search engines. A first category of approaches, called unlinkability, aims at disassociating the query and the identity of its requester. A second category of approaches, called indistinguishability, aims at hiding user’s queries or user’s interests by either obfuscating user’s queries, or forging new fake queries. This paper presents a study of the level of protection offered by three popular solutions: Tor-based, TrackMeNot, and GooPIR. For this purpose, we present an efficient and scalable attack – SimAttack – leveraging a similarity metric to capture the distance between preliminary information about the users (i.e., history of query) and a new query. SimAttack de-anonymizes up to 36.7 % of queries protected by an unlinkability solution (i.e., Tor-based), and identifies up to 45.3 and 51.6 % of queries protected by indistinguishability solutions (i.e., TrackMeNot and GooPIR, respectively). In addition, SimAttack de-anonymizes 6.7 % more queries than state-of-the-art attacks and dramatically improves the performance of the attack on TrackMeNot by 23.6 %, while retaining an execution time faster by two orders of magnitude.
Die Arbeit behandelt zunächst den Tatbestand der Marktmanipulation aus kriminologischer und wirtschaftlicher Sicht.
Im Anschluss wird der damit verbundene Straftatbestand aus der Perspektive des deutschen, spanischen und europäischen Rechts analysiert. Dabei werden auch kriminalpolitische Aspekte, wie die Privatisierung des Strafrechts, die "regulierte Selbstregulierung" und das europäische Gesetzgebungsverfahren berücksichtigt.
Im zweiten Teil der Arbeit werden die Möglichkeiten der Prävention und Detektion solchen Verhaltens durch Compliance-Programme erörtert. In diesem Zusammenhang spielt auch die strafrechtliche Verantwortlichkeit juristischer Personen eine bedeutende Rolle.
Die Dissertation "Burnout bei Lehrerinnen und Lehrern 45+" beinhaltet eine kritische Auseinandersetzung mit den Ursachen, die speziell bei Lehrerinnen und Lehrern im mittleren Lebensalter zum Ausbrennen führen. Es wird dabei von einem multifaktoriellen Ansatz ausgegangen. Beleuchtet werden systemische, biologische und organisationspsychologische Faktoren aber auch Einflüsse der Life-Event-Forschung. Untersucht werden darüber hinaus die Personalführungskompetenzen von Vorgesetzten ebenso wie die Einflüsse von Altersunterschieden im Kollegium. Zuletzt setzt sich die Arbeit mit bestehenden Präventionsangeboten auseinander und diskutiert deren Nutzen für ältere Lehrkräfte.
Die Forschungsarbeit beschreibt die Begleitung einer Schule über mehrere Jahre hinweg.
Dabei fokussiert sich die Untersuchung auf die Ausgangsfrage wie sich schulisches Wohlbefinden bei Schülern steigern lässt.
Das Forschungsanliegen wird durch die Idee geleitet, die Eigenaktivität der Schüler zu fördern.
Following an “agency-oriented Urban Theory” as advanced by Smith (2001), this study takes the urban landscape of Vinh City in Central Vietnam as a starting point into an investigation of multiple visions of modernity (Eisenstadt, 2000) put forward by social actors, as well as into urban change resulting from the implementation of such visions. Focusing on the period from 1973 to 2011, it traces the application of three different visions for urban development in Vinh: The Socialist City, The Modern and Civilized City, and the Participatory City. Projects aiming at implementing these visions in Vinh that are presented in this study have one thing in common: they are informed by a specific view of what a city is and what it should be, and their implementation aims at changing the city in the desired direction. This goal involves not only physical change of the city, but also institutional change in the urban society. To grasp the interplay between visions of a modern city, their application through concrete projects, and the results of these implementations, the study operates with two specific terms: modern projects, and urban change. After introducing Vinh and its history, the thesis presents the period of the vision of The Socialist City and its application in Vinh through cooperation between Vietnam and the German Democratic Republic in the 1970s. It then moves on to contemporary period starting in the 1990s, during which varying and conflicting modern projects for the city were put forward by different social actors cooperating in joint projects on urban development: the Modern and Civilized City and the Participatory City. While the modes of cooperation differed between the two periods, the study concludes with the argument that the impact of these transnational projects has led to path-dependent, as well as ambivalent, urban change in Vinh.
Management accounting information is used in organizations to facilitate decision making and to influence actions for management control. Decisions and actions include the allocation of resources within a firm, coordination across organizational units, costing, pricing, compensation, and incentives. There are many ways how management accounting information is provided, including performance measurement, budgeting, capital budgeting, valuation, inventory systems, product-costing systems, and transfer pricing systems.
Die vorliegende Arbeit untersucht auf Basis einer umfassenden weltweiten empirischen Befragung die Arbeitsweise und das Entscheidungsverhalten von Private Equity Professionals in der Transaktionspraxis. Ausgehend von einer empirischen Beurteilung von Due Diligence mit Hinblick auf die Notwendigkeit ihrer Durchführung im Kontext von Informations- und Prognoseproblem zeigt die Untersuchung auf, wie sich die quantitative Arbeit in der Private Equity Praxis ausgestaltet und ordnet diese in ihrem Zusammenspiel mit weichen Faktoren und Expertenwissen bzw. persönlicher Erfahrung ein. Zuletzt wird auf Basis der verfügbaren Daten eine Brücke zwischen Einsatz & Rolle quantitativer Methoden und weicher Faktoren bei der Investitionsentscheidung und der Performance von Private Equity Gesellschaften geschlagen.
Die Arbeit gliedert sich in folgende sechs Hauptabschnitte:
- Einleitung
- Aktuelle Forschung zu Private Equity und Motivation der Arbeit
- Private Equity – eine Einführung
- Grundlegende Informationsprobleme und Unsicherheiten bei einem Unternehmenskauf: Informationsasymmetrien und Prognoseproblem
- Empirische Untersuchung: Due Diligence im Private Equity – Einsatz und Rolle quantitativer Methoden bei Private Equity Transaktionen
- Schlussbemerkung und Ausblick
Die vorgelegte Dissertationsschrift setzt sich empirisch mit Themen der Lokalen Politischen Ökonomie auseinander. Durch die Analyse bayerischer Kommunaldaten werden kausale Effekte parteipolitischer Machtverhältnisse, kausale Effekte von Parteibanden auf das Zuteilen legaler Renten sowie kausale Effekte steigender Bezahlung auf die Eigenschaften von Lokalpolitikern untersucht.
This thesis attempts to investigate the Noether, Dedekind, and Kähler differents for a 0-dimensional scheme X in the projective n-space P^n_K over an arbitrary field K. In particular, we focus on studying the relations between the algebraic structure of these differents and geometric properties of the scheme X.
In Chapter 1 we give an outline to the problems this thesis is concerned with, a brief literature review for each problem, and the main results regarding these problems. Chapter 2 contains background results that we will need in the subsequent chapters. We introduce the concept of maximal p_j-subschemes of a 0-dimensional scheme X and give some descriptions of them and their Hilbert functions. Furthermore, we generalize the notion of a separator of a subscheme of X of degree deg(X)-1 to a set of separators of a maximal p_j-subscheme of X. In Chapter 3 we explore the Noether, Dedekind, and Kähler differents for 0-dimensional schemes X. First we define these differents for X, and take a look at how to compute these differents and examine their relations. Then we give an answer to the question "What are the Hilbert functions of these differents?" in some cases.
In Chapter 4 we use the differents to investigate the Cayley-Bacharach property of 0-dimensional schemes over an arbitrary field K. The principal results of this chapter are characterizations of CB-schemes and of arithmetically Gorenstein schemes in terms of their Dedekind differents and a criterion for a 0-dimensional smooth scheme to be a complete intersection. We also generalize some results such as Dedekind's formula and the characterization of the Cayley-Bacharach property by using Liaison theory. In addition, several propositions on the uniformities are proven. In Chapter 5 we are interested in studying the Noether, Dedekind, and Kähler differents for finite special classes of schemes and finding out some applications of these differents. First, we investigate these differents for reduced 0-dimensional almost complete intersections X in P^n_K over a perfect field K. Then we investigate the relationships between these differents and the i-th Fitting ideals of the module of Kähler differentials of the homogeneous coordinate ring of X. Finally, we look more closely at the Hilbert functions and the regularity indices of these differents for fat point schemes.
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.