Το Ειδικό Καθεστώς οικονομικών δραστηριοτήτων του Ελληνικού Κράτους ως μέλους της Ευρωπαϊκής Ένωσης και Ελλήνων υπηκόων σε χώρες των Βαλκανίων: θεωρητικές προσεγγίσεις και εμπειρικοί προσανατολισμοί

Doctoral thesis (2016)

During the two decades from 1990 to 2010, the Balkans was the only European region to suffer a cruel reversal. On the one hand, it welcomed the transition to a free economy, despite the difficulties it ... [more ▼]

During the two decades from 1990 to 2010, the Balkans was the only European region to suffer a cruel reversal. On the one hand, it welcomed the transition to a free economy, despite the difficulties it had to overcome. On the other hand, it experienced the merciless reality of war, when it was convulsed by successive waves of various armed confrontations extending over most of its territory. These left severe and far-reaching post-conflict symptoms: a shattered economic and social base; unemployment and poverty bordering on humanitarian crisis; morale broken, infrastructure in ruins. Yet at the same time this fragmented, conflict-ridden region became the theatre of international collaboration of unprecedented quality and scale. With more than 22 donor/sponsor countries and investors, as well as international and multilateral organisations, the total flow of official development assistance and foreign direct investment in the region is estimated at more than 150 billion euro during the period in question. The region is therefore a model of reorganisation, restructuring and economic development. As an integral part of this broader geopolitical and economic scene, Greece is participating economically, in common with other ‘players’, in the ‘rebirth’ and integration of the region into the international community, both directly, by providing official development assistance (ODA) under the Hellenic Plan for the Economic Reconstruction of the Balkans (HPERB), and indirectly, by promoting Greece’s foreign direct investment (FDI) in the region in a variety of ways, mainly through subsidies. Thus, Greece evolved from a long-term ‘net importer’ of investments into an ‘exporter’ focused on the Balkans, where it ranked among the top sources of ODA and FDI. This study approaches the subject holistically, examining the dual nature of Greece’s involvement and analysing the broader economic and geopolitical setting. The dual economic involvement of the Greek State in the Balkans is also examined from a dual perspective within the scope of this doctoral thesis, both from a theoretical and from an empirical point of view, using business strategy models such as PEST, SWOT, VRIO, as well as Porter models of ‘competitive forces’, and the ‘value chain’. This thesis examines the reasons why Greece’s involvement was inevitable; investigates the compatibility between Greece’s involvement and the country’s other commitments within the EU; studies the advisability and usefulness of the endeavour; compares Greece with other countries as a provider of ODA and FDI; analyses and evaluates the HPERB; assesses the role of the Greek State and any encouragement and guidance of FDI through Greek subsidies; and scrutinises the characteristics of Greek FDI, in terms of competitiveness and the links with the parent companies in Greece. This subject is novel in an academic context, because a survey of the bibliography shows that this combined dual line of inquiry has not attracted scientific attention, as the existing studies focus on one or other of the two aspects, not both together. Furthermore, this paper is original in terms of method, firstly because it examines the subject from a new viewpoint, that of business strategy, and secondly because it uses the relevant models in new ways, with new applications. The subject, through the study of what has been achieved, remains ‘topical’ and retains its significance, as guidance to future policy makers and/or investors, especially during the current unfavourable economic situation in Greece, because, apart from any conclusions regarding the impact of Greek economic involvement in the Balkans, foreign markets represent a way out of the Greek recession. [less ▲]

Messen (Mittelalter/Frühe Neuzeit)

in Historisches Lexikon Bayerns (2016)

Boosting Static Security Analysis of Android Apps through Code Instrumentation

Doctoral thesis (2016)

Within a few years, Android has been established as a leading platform in the mobile market with over one billion monthly active Android users. To serve these users, the official market, Google Play ... [more ▼]

Within a few years, Android has been established as a leading platform in the mobile market with over one billion monthly active Android users. To serve these users, the official market, Google Play, hosts around 2 million apps which have penetrated into a variety of user activities and have played an essential role in their daily life. However, this penetration has also opened doors for malicious apps, presenting big threats that can lead to severe damages. To alleviate the security threats posed by Android apps, the literature has proposed a large body of works which propose static and dynamic approaches for identifying and managing security issues in the mobile ecosystem. Static analysis in particular, which does not require to actually execute code of Android apps, has been used extensively for market-scale analysis. In order to have a better understanding on how static analysis is applied, we conduct a systematic literature review (SLR) of related researches for Android. We studied influential research papers published in the last five years (from 2011 to 2015). Our in-depth examination on those papers reveals, among other findings, that static analysis is largely performed to uncover security and privacy issues. The SLR also highlights that no single work has been proposed to tackle all the challenges for static analysis of Android apps. Existing approaches indeed fail to yield sound results in various analysis cases, given the different specificities of Android programming. Our objective is thus to reduce the analysis complexity of Android apps in a way that existing approaches can also succeed on their failed cases. To this end, we propose to instrument the app code for transforming a given hard problem to an easily-resolvable one (e.g., reducing an inter-app analysis problem to an intra-app analysis problem). As a result, our code instrumentation boosts existing static analyzers in a non-invasive manner (i.e., no need to modify those analyzers). In this dissertation, we apply code instrumentation to solve three well-known challenges of static analysis of Android apps, allowing existing static security analyses to 1) be inter-component communication (ICC) aware; 2) be reflection aware; and 3) cut out common libraries. ICC is a challenge for static analysis. Indeed, the ICC mechanism is driven at the framework level rather than the app level, leaving it invisible to app-targeted static analyzers. As a consequence, static analyzers can only build an incomplete control-flow graph (CFG) which prevents a sound analysis. To support ICC-aware analysis, we devise an approach called IccTA, which instruments app code by adding glue code that directly connects components using traditional Java class access mechanism (e.g., explicit new instantiation of target components). Reflection is a challenge for static analysis as well because it also confuses the analysis context. To support reflection-aware analysis, we provide DroidRA, a tool-based approach, which instruments Android apps to explicitly replace reflective calls with their corresponding traditional Java calls. The mapping from reflective calls to traditional Java calls is inferred through a solver, where the resolution of reflective calls is reduced to a composite constant propagation problem. Libraries are pervasively used in Android apps. On the one hand, their presence increases time/memory consumption of static analysis. On the other hand, they may lead to false positives and false negatives for static approaches (e.g., clone detection and machine learning-based malware detection). To mitigate this, we propose to instrument Android apps to cut out a set of automatically identified common libraries from the app code, so as to improve static analyzer’s performance in terms of time/memory as well as accuracy. To sum up, in this dissertation, we leverage code instrumentation to boost existing static analyzers, allowing them to yield more sound results and to perform quicker analyses. Thanks to the afore- mentioned approaches, we are now able to automatically identify malicious apps. However, it is still unknown how malicious payloads are introduced into those malicious apps. As a perspective for our future research, we conduct a thorough dissection on piggybacked apps (whose malicious payloads are easily identifiable) in the end of this dissertation, in an attempt to understand how malicious apps are actually built. [less ▲]

Étude sociolinguistique sur les pratiques linguistiques au sein de familles plurilingues vivant au Grand-Duché de Luxembourg

Doctoral thesis (2016)

The importance of investigating the family language policies within multilingual families living in Luxembourg is primarily based the trilingualism that characterizes Luxembourg, the heterogeneity of its ... [more ▼]

The importance of investigating the family language policies within multilingual families living in Luxembourg is primarily based the trilingualism that characterizes Luxembourg, the heterogeneity of its population, problems faced by immigrant children schooling in Luxembourg’s school and individual’s personal experience with everyday language use as well. Hence, this thesis’s aim is to investigate how parents from different linguistic backgrounds or having the same language of origin communicated with each other prior to the birth of their children and how the birth of these children reshapes the family language environment. Specifically, we aim to understand the parents’ motivations with regard to their language choices and the communication strategies they implement in order to establish a family communication environment. In addition, considering the effects of language contact, we focus on the school languages and their influence on the children’s language at home. In order to achieve this, from a methodological point of view, by combining ethnographic interviews with the recordings of a family conversation, we gained access to the declared and real linguistic practices of ten families with highly diverse linguistic profiles. These families reside between seven and forty-two years in Luxembourg. Further, content analysis was used to examine the migratory experience of each parent. Some of the major reasons why parents adopted a positive attitude towards multilingualism were (a) the language learning and use opportunities offered by Luxembourg and (b) the desire to develop the linguistic capital of their children. Our results later suggest that although children do not participate actively in the language use decision-making process they actively influence the family language environment. Because the languages they learn in school impact the ways in which they speak at home. Moreover, we discovered that once these children have contact with the officially recognised languages in Luxembourg, which might be different from that of the family, they tend to shift their preference towards these dominant languages. In addition, we discovered that there is no standard parental communication strategy for passing the family languages on to the children. Rather, depending on the parents' objectives, they can adopt different strategies. Overall, this thesis opens new perspectives for research that investigates the family language policies of multilingual families by highlighting the relevance of educational dimensions of children with immigrant backgrounds. [less ▲]

Astrocyte phenotype during differentiation: implication of the NFkB pathway

Doctoral thesis (2016)

"do huet dann dacks e Lämmchen mer Läif a Séil gelooss"

Article for general public (2016)

"Advent ist immer!" (Ernst Bloch) Bewusst krirtisch in der Gegenwart, aber offen fü die Zukunft

Article for general public (2016)

Schwierige Transitionen in Arbeit und Übergangsprobleme aus der Sicht von Jugendlichen

Conference given outside the academic context (2016)

ELECTRONIC AND STRUCTURAL PROPERTIES OF BISMUTH- AND RARE-EARTH-FERRITES

Doctoral thesis (2016)

The work of this thesis stands in the framework of the understanding of multiferroics and light induced effects in these materials, more specifically in rare-earth and bismuth ferrites. Iron-based ... [more ▼]

The work of this thesis stands in the framework of the understanding of multiferroics and light induced effects in these materials, more specifically in rare-earth and bismuth ferrites. Iron-based materials offer the advantage of a high magnetic-ordering temperature, commonly well-above room temperature. To understand the coupling between magnetism and crystal lattice and the interaction of a material with light, knowledge about the crystal structure and electronic band structure, respectively, is crucial. In the first part of this work, the structural properties of six rare-earth orthoferrites RFeO3 (R = La, Sm, Eu, Gd, Tb, Dy) are analyzed by Raman scattering (RS). Polarization dependent RS of SmFeO3 and the comparison with first-principle calculations enable the assignment of the measured phonon modes to vibrational symmetries and atomic displacements. This allows correlating the phonon modes with the orthorhombic structural distortions of RFeO3 perovskites. In particular, the positions of two specific Ag modes scale linearly with the two FeO6 octahedra tilt angles, allowing the distortion to be tracked throughout the series. At variance with literature, we find that the two octahedra tilt angles scale differently with the vibration frequencies of their respective Ag modes. This behavior, as well as the general relations between the tilt angles, the frequencies of the associated modes, and the ionic radii are rationalized in a simple Landau model. The precise knowledge about the lattice vibration is used in the second part of the work to investigate the impact of magnetic transitions on crystal lattice of SmFeO3. SmFeO3 stands out of the rest of the rare-earth orthoferrites for its comparably high magnetic transition temperatures. While tuning the temperature through magnetic transitions, the structural properties are probed by RS complemented by resonant ultrasound spectroscopy and linear birefringence measurements. During the Fe3+-spin reorientation phase, we find an important softening of the elastic constants in the resonant-ultrasound spectra. Towards lower temperatures the Sm3+-spins order; this ordering is clearly represented in the Raman spectra in the form of changes of the evolution of certain vibrational bands and additional bands appear in the spectra. The knowledge about the vibrational displacements of the Raman bands allows an investigation of the anomalies related to the Sm3+-spin ordering. Bismuth ferrite can be seen as the role model multiferroic material since it is one of the few room temperature multiferroics with a strong electric polarization. The ferroelectric and magnetic properties have been studied in great detail. In addition to the multiferroic properties, photo-induced phenomena have renewed the interest in BiFeO3. However, for the understanding and tuning of photo-induced effects a profound knowledge of the electronic band structure is important. Despite the extensive study of BiFeO3, the understanding of the electronic transitions remains very limited. In the third part of the thesis, the electronic band structure of BiFeO3 is investigate using RS with twelve different excitation wavelengths ranging from the blue to the near infrared. Resonant Raman signatures (RRS) can be assigned to direct and indirect electronic transitions, as well as in-gap electronic levels, most likely associated with oxygen vacancies. RRS allows to distinguish between direct and indirect transitions even at higher temperatures. Thus, it is found that the remarkable and intriguing variation of the optical band gap with temperature can be related to the shrinking of an indirect electronic band gap, while the energies for direct electronic transitions remain nearly temperature independent. [less ▲]

Contemporary Russia: Der KGB und der feine englische Humor

Article for general public (2016)

Vor genau zehn Jahren wurde in London Alexander Litwinenko (1962-2006), der frühere KGB-Offizier, der durch seine Kritik an der Spitze des Geheimdienstes prominent wurde, mit einer tödlichen Dosis des ... [more ▼]

Vor genau zehn Jahren wurde in London Alexander Litwinenko (1962-2006), der frühere KGB-Offizier, der durch seine Kritik an der Spitze des Geheimdienstes prominent wurde, mit einer tödlichen Dosis des radioaktiven Elements Polonium 210 vergiftet. [less ▲]