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See detailSecond order Poincaré inequalities and CLTs on Wiener space
Nourdin, Ivan UL; Peccati, Giovanni UL; Reinert, Gesine

in Journal of Functional Analysis (2009), 257(2), 593--609

Detailed reference viewed: 168 (2 UL)
See detailThe Second World War in the Twenty-first Century Museum: From Narrative, Memory, and Experience to Experientiality
Janz, Nina UL

in The Military History Journal (2021), 85(1), 293-94

Detailed reference viewed: 73 (2 UL)
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See detailSecond-Chance Alternatives and Maintained Inequality in Access to Higher Education in Israel
Bar-Haim, Eyal UL; Blank, Carmel

in Social Inclusion (2019), 7(1), 28-37

Abstract Access to higher education (HE) has a long history. To offer a view on the current debates and worldwide issues regarding access to HE, this editorial depicts how the control of educational ... [more ▼]

Abstract Access to higher education (HE) has a long history. To offer a view on the current debates and worldwide issues regarding access to HE, this editorial depicts how the control of educational access has historically been used as an instrument of governance at the interface of two processes: social stratification and the territorialisation of politics. Access to HE has remained embedded in these large structural processes even though HE has expanded from a highly elitist institution into mass education systems with equity of educational opportunities having become a desirable goal across societies. Analysing these processes helps understand the complex mechanisms producing inequalities in HE today, which are brought together by the ten articles composing this special issue. Tacking stock of how inequalities in access are produced in different continents, countries, HE Institutions, applying to different social groups though evolving mechanisms, these articles document the importance of contrasting methodological and theoretical approaches to produce comprehensive knowledge on this sensitive issue for democratic societies. [less ▲]

Detailed reference viewed: 129 (1 UL)
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See detailSecond-Order Differential Collisions for Reduced SHA-256.
Biryukov, Alex UL; Lamberger, Mario; Mendel, Florian et al

in 17th International Conference on the Theory and Application of Cryptology and Information Security (2011)

In this work, we introduce a new non-random property for hash/compression functions using the theory of higher order differentials. Based on this, we show a second-order differential collision for the ... [more ▼]

In this work, we introduce a new non-random property for hash/compression functions using the theory of higher order differentials. Based on this, we show a second-order differential collision for the compression function of SHA-256 reduced to 47 out of 64 steps with practical complexity. We have implemented the attack and provide an example. Our results suggest that the security margin of SHA-256 is much lower than the security margin of most of the SHA-3 finalists in this setting. The techniques employed in this attack are based on a rectangle/boomerang approach and cover advanced search algorithms for good characteristics and message modification techniques. Our analysis also exposes flaws in all of the previously published related-key rectangle attacks on the SHACAL-2 block cipher, which is based on SHA-256. We provide valid rectangles for 48 steps of SHACAL-2. [less ▲]

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See detailSecond-order Doppler-shift corrections in free-fall absolute gravimeters
Rothleitner, Christian UL; Francis, Olivier UL

in Metrologia (2011), 48(3), 187-195

In a free-fall absolute gravimeter usually a Michelson type interferometer is employed to track the trajectory of a freely falling retroreflector. The accelerated motion of the retroreflector produces a ... [more ▼]

In a free-fall absolute gravimeter usually a Michelson type interferometer is employed to track the trajectory of a freely falling retroreflector. The accelerated motion of the retroreflector produces a Doppler-shift in the laser wavelength. From the interference signal (beat signal) of the Doppler-shifted and the reference electromagnetic waves the relative motion of the freely falling retroreflector with respect to an inertial reference retroreflector is reconstructed. Considerations of second-order Doppler-shift terms lead to a correction in the acceleration due to gravity of several microgals (1 µGal = 10 nm s −2 ). This correction is commonly called speed of light correction . To date different correction formulae have been proposed, which differ by several microgals. In this paper we review several previous publications and show the reasons for the different results. [less ▲]

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See detailSecond-order elasticity of liquid crystals within their nematic state at high frequencies
Krüger, Jan-Kristian UL; Grammes, C.; Jiménez, R. et al

in Physical Review. E : Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics (1995), 51(3), 2115-2128

Within this work we present Brillouin and ultrasonic investigations performed on the liquid crystals p-methoxybenzylidene p-(n-butylaniline) (MBBA), p-azoxyanisol (PAA), 4-cyano-4-n-alkylbiphenyles (nCB ... [more ▼]

Within this work we present Brillouin and ultrasonic investigations performed on the liquid crystals p-methoxybenzylidene p-(n-butylaniline) (MBBA), p-azoxyanisol (PAA), 4-cyano-4-n-alkylbiphenyles (nCB), and 4-n-pentoxybenzylidene-4'-n-octoaniline (5O.8). Special attention has been paid to the evolution of a significant splitting of the two longitudinal polarized acoustic modes within the nematic phase. Angle-resolving Brillouin spectroscopy allowed the determination of the complete stiffness tensors and hence a discussion of the propagation of quasitransverse polarized acoustic modes in the nematic state of liquid crystals. We analyze the behavior of the eigenvectors of the relevant acoustic modes and discuss their significance for the propagation of quasishear modes. For 5O.8 we report an acoustic instability within its nematic state. We confirm the existence of a universal thermal relaxation mechanism of weak activation energy for the nematic state of classical liquid crystals. The observed hypersonic anisotropy is discussed in terms of that relaxation mechanism and is compared with that of glass-forming liquid crystals. [less ▲]

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See detailSecond-order Quantifier Elimination Foundations, Computational Aspects and Applications (Studies in Logic Mathematical Logic and Foundations)
Gabbay, Dov M. UL; Schmidt, R.; Szalas, A.

Book published by College publications (2008)

Detailed reference viewed: 103 (0 UL)
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See detailSecond-principles methods for large-scale simulations of realistic functional oxides
Escorihuela Sayalero, Carlos UL

Doctoral thesis (2019)

The application of Condensed Matter theory via simulation has been over the last decades a solid approach to research in Materials Science. In particular for the case of Perovskite materials the research ... [more ▼]

The application of Condensed Matter theory via simulation has been over the last decades a solid approach to research in Materials Science. In particular for the case of Perovskite materials the research has been extensive, and customarily (but not only) performed using Density Functional Theory. The collective effort to develop lighter simulation techniques and exploring different theoretical approaches to computationally study materials has provided the scientific community with the possibility to strengthen the interaction between experimental and theoretical research. However, the access to large-scale simulations is still nowadays limited due to the high computational cost of such simulations. In 2013 J. C. Wojdel et al. presented a theory of modelization of crystals known as second-principles models, and which are the central point of the development of my work. In this Thesis I develop in depth a novel methodology to produce second-principles models efficiently and in a quasi-automatic way from Density Functional Theory data. The scheme presented here identifies, given a set of reliable data to be fit, the most relevant atomic couplings of a system. The fitting process that I present is also analytical, which translates into a fast and accurate model production. I also explore the modelization of chemically inhomogeneous or nanostructured systems using second-principles models. Moreover, I present a heuristic procedure to produce models of the inhomogeneous material which is efficient and sound. Finally, I also show examples of complex problems that can be tackled thanks to the second-principles models, such as the character of 180º anti-phase domain walls in SrTiO3, thermodynamical studies of heat transport across 180º domain walls in PbTiO3 and the reproduction of experimentally-observed polarization vortices in (PbTiO3)n/(SrTiO3)n superlattices. [less ▲]

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See detailSecondary Issues and Party Politics. An Application to Environmental Policy
Anesi, Vincent UL; De Donder, Philippe

in Social Choice and Welfare (2011), 36

This article develops a political economy model to assess the interplay between party formation and an environmental policy dimension viewed as secondary to the redistributive dimension. We define being a ... [more ▼]

This article develops a political economy model to assess the interplay between party formation and an environmental policy dimension viewed as secondary to the redistributive dimension. We define being a secondary issue in terms of the intensity of preferences over this issue rather than in terms of the proportion of voters who care for the environment. Equilibrium policies are the outcome of an electoral competition game between endogenous parties. We obtain the following results: (i) The Pigouvian tax never emerges in an equilibrium; (ii) The equilibrium environmental tax is larger when there is a minority of green voters; (iii) Stable green parties exist only if there is a minority of green voters and income polarization is large enough relative to the saliency of the environmental issue. We also study the redistributive policies advocated by green parties. [less ▲]

Detailed reference viewed: 117 (3 UL)
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See detailSecondary law provisions on media ownership transparency
Cole, Mark David UL

in Capello, Maja (Ed.) Transparency of media ownership (IRIS Special 2-2021) (2022)

Detailed reference viewed: 15 (0 UL)
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See detailSecondary phase formation during monoclinic Cu2SnS3 growth for solar cell application
De Wild, Jessica UL; Robert, Erika UL; El Adib, Brahime et al

in Solar Energy Materials and Solar Cells (2016)

Detailed reference viewed: 218 (9 UL)
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See detailSecondary qualitative analysis of the international PISA survey
Houssemand, Claude UL

Scientific Conference (2007, September)

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See detailSecondary school principals and liminality in Polish Upper Silesia (1919-1939)
Venken, Machteld UL

in Journal of Modern European History (2021), 19(2), 206-221

Establishing and implementing rules that would teach young people to become active citizens became a crucial technique for turning those spots on the map of Europe whose sovereignty had shifted after ... [more ▼]

Establishing and implementing rules that would teach young people to become active citizens became a crucial technique for turning those spots on the map of Europe whose sovereignty had shifted after World War I into lived social spaces. This article analyses how principals of borderland secondary schools negotiated transformation in Polish Upper Silesia with the help of Arnold Van Gennep’s notion that a shift in social statuses possessed a spatiality and temporality of its own. The article asks whether and how school principals were called on to offer elite training that would make Polish Upper Silesia more cohesive with the rest of Poland in terms of the social origins of pupils and the content of the history curriculum. In addition, it examines the extent to which borderland school principals accepted, refuted, or helped to shape that responsibility. The social origins of pupils are detected through a quantitative analysis of recruitment figures and the profiles of pupils’ parents. This analysis is combined with an exploration of how school principals provided a meaningful explanation of the recent past (World War I and the Silesian Uprisings). The article demonstrates that while school principals were historical actors with some room to make their own decisions when a liminal space was created, changed, and abolished, it was ultimately a priest operating in their shadows who possessed more possibilities to become a master of ceremonies leading elite education through its rites of passage. [less ▲]

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See detailSecondary User Scheduling Under Throughput Guarantees for the Primary Network
Kapetanovic, Dzevdan UL; Butt, Majid; Chatzinotas, Symeon UL et al

in IEEE Vehicular Technology Conference (VTC), Fall 2013 (2013, September 02)

This work addresses scheduling in a cognitive radio scenario where a minimum throughput for the downlink primary network (PN) is guaranteed to each user with an associated violation probability ... [more ▼]

This work addresses scheduling in a cognitive radio scenario where a minimum throughput for the downlink primary network (PN) is guaranteed to each user with an associated violation probability (probability of not obtaining the guaranteed throughput). The primary network is surrounded by multiple downlink secondary networks, each aiming to maximize its network throughput. Scheduling in PN is performed independent of the secondary networks. Some information about the PN is available at the central scheduler that is responsible for scheduling the secondary networks. The contribution of this work is to apply a novel scheduler to the PN which is more robust to QoS degradations resulting from the secondary networks than other state of the art schedulers. This is validated by numerical simulations of the cognitive radio network. [less ▲]

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See detailSecrecy Analysis of Random Wireless Networks with Multiple Eavesdroppers
Vuppala, Satyanarayana UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Proceedings of IEEE Inter. Symp. on Personal, Indoor and Mobile Radio Communications (PIMRC), Montreal, Canada (2017)

Detailed reference viewed: 175 (4 UL)
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See detailSecrecy Analysis on Network Coding in Bidirectional Multibeam Satellite Communications
Kalantari, Ashkan UL; Ottersten, Björn UL

in IEEE Transactions on Information Forensics and Security (2015)

Network coding is an efficient means to improve the spectrum efficiency of satellite communications. However, its resilience to eavesdropping attacks is not well understood. This paper studies the ... [more ▼]

Network coding is an efficient means to improve the spectrum efficiency of satellite communications. However, its resilience to eavesdropping attacks is not well understood. This paper studies the confidentiality issue in a bidirectional satellite network consisting of two mobile users who want to exchange message via a multibeam satellite using the XOR network coding protocol. We aim to maximize the sum secrecy rate by designing the optimal beamforming vector along with optimizing the return and forward link time allocation. The problem is non-convex, and we find its optimal solution using semidefinite programming together with a 1-D search. For comparison, we also solve the sum secrecy rate maximization problem for a conventional reference scheme without using network coding. Simulation results using realistic system parameters demonstrate that the bidirectional scheme using network coding provides considerably higher secrecy rate compared to that of the conventional scheme. [less ▲]

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See detailSecrecy Capacity of the Primary System in a Cognitive Radio Network
Nguyen, van Dinh UL

in IEEE Transactions on Vehicular Technology (2015), 64(8), 3834-3843

With fast growth of wireless services, secrecy has become an increasingly important issue for wireless networks. In this paper, we investigate the secrecy capacity of the primary system in a cognitive ... [more ▼]

With fast growth of wireless services, secrecy has become an increasingly important issue for wireless networks. In this paper, we investigate the secrecy capacity of the primary system in a cognitive radio system based on artificial noise, which has been proposed for dealing with the eavesdropper. We first consider a special case of one eavesdropper and two regimes of the eavesdropping channel condition. Specifically, we analyze the impact of interference generated by a secondary system toward the primary system in a cognitive radio system. The channel state information (CSI) of the primary channel is assumed to be perfectly known at both the primary transmitter and receiver, whereas that of the eavesdropper is partially known. Under these assumptions, we derive analytical expressions for the ergodic secrecy capacity in the cases of strong eavesdropping channel and weak eavesdropping channel and analyze the impact of the secondary system on the primary ergodic secrecy capacity. Moreover, we extend the analysis to the general case of arbitrary eavesdropping channel condition and arbitrary number of eavesdroppers. Some numerical results will be also presented to verify the analysis. [less ▲]

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See detailSecrecy Energy Efficiency Optimization for MISO and SISO Communication Networks
Kalantari, Ashkan UL; Maleki, Sina UL; Chatzinotas, Symeon UL et al

in The 16th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) (2015, June 28)

Energy-efficiency, high data rates and secure communications are essential requirements of the future wireless networks. In this paper, optimizing the secrecy energy efficiency is considered. The optimal ... [more ▼]

Energy-efficiency, high data rates and secure communications are essential requirements of the future wireless networks. In this paper, optimizing the secrecy energy efficiency is considered. The optimal beamformer is designed for a MISO system with and without considering the minimum required secrecy rate. Further, the optimal power control in a SISO system is carried out using an efficient iterative method, and this is followed by analyzing the trade-off between the secrecy energy efficiency and the secrecy rate for both MISO and SISO systems. [less ▲]

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See detailSecrecy sum-rate for orthogonal random beamforming with opportunistic scheduling
Krikidis, Ioannis; Ottersten, Björn UL

in IEEE Signal Processing Letters (2013), 2(20), 141-144

In this letter, we employ orthogonal random beamforming (ORBF) for the worst-case multi-user downlink scenario where each user is wiretapped by one eavesdropper. Two opportunistic scheduling techniques ... [more ▼]

In this letter, we employ orthogonal random beamforming (ORBF) for the worst-case multi-user downlink scenario where each user is wiretapped by one eavesdropper. Two opportunistic scheduling techniques that ensure confidentiality by exploiting multi-user diversity are investigated; the first technique (optimal) requires limited feedback of the effective signal-to-interference ratio (SIR) from all the users and the eavesdroppers while the second technique (suboptimal) incorporates SIR knowledge from only the legitimate users. By using extreme value theory, we derive the achievable SIR-based secrecy sum-rate and the associated scaling laws for both scheduling techniques. [less ▲]

Detailed reference viewed: 161 (0 UL)