PotLLL: A Polynomial Time Version of LLL With Deep Insertions

Lattice reduction algorithms have numerous applications in number theory, algebra, as well as in cryptanalysis. The most famous algorithm for lattice reduction is the LLL algorithm. In polynomial time it computes a reduced basis with provable output quality. One early improvement of the LLL algorithm was LLL with deep insertions (DeepLLL). The output of this version of LLL has higher quality in practice but the running time seems to explode. Weaker variants of DeepLLL, where the insertions are restricted to blocks, behave nicely in practice concerning the running time. However no proof of polynomial running time is known. In this paper PotLLL, a new variant of DeepLLL with provably polynomial running time, is presented. We compare the practical behavior of the new algorithm to classical LLL, BKZ as well as blockwise variants of DeepLLL regarding both the output quality and running time.Comment: 17 pages, 8 figures; extended version of arXiv:1212.5100 [cs.CR

Digitalization of business models : impacts and opportunities for the healthcare industry : a multiple case study approach

The purpose of this applied-research project is to understand how digitalized business models can be assessed and analyzed with regard to their success in the broad field of healthcare. Digitalization holds enormous opportunities, but also requires a particular degree of tact and sensitivity concerning business model design. In order to propose specific guidelines for business model design this paper highlights the major dynamics of the digital business ecosystem, like turbulence, disruptiveness and blurred industry boundaries, and describes Omar El Sawy’s VISOR model, with its components Value Proposition, Interface, Service Platform, Organizing Model and Revenue Model. Following this, the main part consists of two case studies, Nike+ and Kinematix, and narrates the stories of one major, incumbent player and of one new entrant, with the purpose to achieve extensive insights on different perspectives of digital business models. Both companies operate in the field of E-health, more specifically running wearables, Nike with a more generic, Kinematix a more sophisticated approach. The main implications drawn from the case studies cover inter-industry partnership choices, the potential of motivational force based on Social Media, the transformation of the patient-caregiver relationship, the barriers to overcome originating from primary healthcare players, as well as specific dynamic and adaptive capabilities. The paper concludes with suggestions to stimulate future research to find solutions and ways to transform healthcare in a more advanced, forward-looking sector.Esta tese tem como objectivo perceber a aplicação de modelos de negócios digitais no sector da saúde e entender o seu sucesso. As oportunidades deste modelo de negócio são várias contudo o seu sucesso na aplicação requer sensibilidade e conhecimento especifico. Este trabalho propõe directrizes para lidar com este tipo de abordagem e realça as principais características deste modelo de negócio como turbulência, perturbações devido a esta nova visão de negócio, fronteiras da Indústria mal definidas e explica o modelo VISOR de Omar El Sawy em todas as suas componentes: Proposição de Valor, Interface, Plataforma de Serviço Modelo de Organização e de Receita. O corpo desta tese analisa os casos de estudo Nike+ e Kinematix descrevendo a história de um primeiro modelo já incumbente e de outro que é recente, respectivamente. Este processo pretende compreender duas estratégias diferentes em modelos de negócio digitais no sector da saúde. Ambas as empresas operam no segmento de E-saúde, especificamente roupa de corrida. Nike adopta uma abordagem mais genérica enquanto Kinematix tem uma abordagem mais específica. A principal implicação do estudo dos casos são parcerias inter-indústria, o potencial das redes socias em factores motivacionais, a transformação da relação paciente-cuidador, as barreiras a ultrapassar provenientes dos fornecedores de cuidados de saúde primários, bem como as dinâmicas e capacidades adaptativas. No fim deste trabalho são enumeradas sugestões para pesquisa académica futura com vista a transformar os cuidados de saúde num sector mais moderno e avançado

AstraLux: the Calar Alto Lucky Imaging Camera

AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope, based on an electron-multiplying high speed CCD. By selecting only the best 1-10% of several thousand short exposure frames, AstraLux provides nearly diffraction limited imaging capabilities in the SDSS i' and z' filters over a field of view of 24x24 arcseconds. By choosing commercially available components wherever possible, the instrument could be built in short time and at comparably low cost. We present the instrument design, the data reduction pipeline, and summarise the performance and characteristicsComment: 12 pages, 7 figures, to appear in "Ground-based and Airborne Instrumentation for Astronomy II" SPIE conference, Marseille, 23-28 June 200

Numerical calculation of the complex berry phase in non-Hermitian systems

We numerically investigate topological phases of periodic lattice systems in tight-binding description under the influence of dissipation. The effects of dissipation are effectively described by $\mathcal{PT}$-symmetric potentials. In this framework we develop a general numerical gauge smoothing procedure to calculate complex Berry phases from the biorthogonal basis of the system's non-Hermitian Hamiltonian. Further, we apply this method to a one-dimensional $\mathcal{PT}$-symmetric lattice system and verify our numerical results by an analytical calculation.Comment: 7 pages, 3 figures, minor modifications in the final versio

Scientific Highlights from Observations of Active Galactic Nuclei with the MAGIC Telescope

Since 2004, the MAGIC gamma-ray telescope has newly discovered 6 TeV blazars. The total set of 13 MAGIC-detected active galactic nuclei includes well-studied objects at other wavelengths like Markarian 501 and the giant radio galaxy M87, but also the distant the flat-spectrum radio quasar 3C 279, and the newly discovered TeV gamma-ray emitter S5 0716+71. In addition, also long-term and multi-wavelength studies on well-known TeV blazars and systematic searches for new TeV blazars have been carried out. Here we report selected highlights from recent MAGIC observations of extragalactic TeV gamma-ray sources, emphasizing the new physics insights MAGIC was able to contribute.Comment: 4 pages, 2 figures, submitted to proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008

Thermodynamic reaction control of nucleoside phosphorolysis

Nucleoside analogs represent a class of important drugs for cancer and antiviral treatments. Nucleoside phosphorylases (NPases) catalyze the phosphorolysis of nucleosides and are widely employed for the synthesis of pentose‐1‐phosphates and nucleoside analogs, which are difficult to access via conventional synthetic methods. However, for the vast majority of nucleosides, it has been observed that either no or incomplete conversion of the starting materials is achieved in NPase‐catalyzed reactions. For some substrates, it has been shown that these reactions are reversible equilibrium reactions that adhere to the law of mass action. In this contribution, we broadly demonstrate that nucleoside phosphorolysis is a thermodynamically controlled endothermic reaction that proceeds to a reaction equilibrium dictated by the substrate‐specific equilibrium constant of phosphorolysis, irrespective of the type or amount of NPase used, as shown by several examples. Furthermore, we explored the temperature‐dependency of nucleoside phosphorolysis equilibrium states and provide the apparent transformed reaction enthalpy and apparent transformed reaction entropy for 24 nucleosides, confirming that these conversions are thermodynamically controlled endothermic reactions. This data allows calculation of the Gibbs free energy and, consequently, the equilibrium constant of phosphorolysis at any given reaction temperature. Overall, our investigations revealed that pyrimidine nucleosides are generally more susceptible to phosphorolysis than purine nucleosides. The data disclosed in this work allow the accurate prediction of phosphorolysis or transglycosylation yields for a range of pyrimidine and purine nucleosides and thus serve to empower further research in the field of nucleoside biocatalysis.DFG, 390540038, EXC 2008: UniSysCatTU Berlin, Open-Access-Mittel - 201

Predicting building age from urban form at large scale

To stay within 1.5 °C of global warming, reducing energy-related emissions in the building sector is essential. Rather than generic climate recommendations, this requires tailored, low-carbon urban planning solutions and spatially explicit methods that can inform policy measures at urban, street and building scale. Here, we propose a scalable method that is able to predict building age information in different European countries using only open urban morphology data. We find that spatially cross-validated regression models are sufficiently robust to generalize and predict building age in unseen cities with a mean absolute error (MAE) between 15.3 years (Netherlands) and 19.9 years (Spain). Our experiments show that large-scale models improve generalization for predicting across cities, but are not needed to infer missing data within known cities. Filling data gaps within known cities is possible with a MAE between 9.6 years (Netherlands) and 16.7 years (Spain). Overall, our results demonstrate the feasibility of generating missing age data in different contexts across Europe and informing climate mitigation policies such as large-scale energy retrofits. For the French residential building stock, we find that using age predictions to target retrofit efforts can increase energy savings by more than 50% compared to missing age data. Finally, we highlight challenges posed by data inconsistencies and urban form differences between countries that need to be addressed for an actual roll-out of such methods

A note on balanced edge-colorings avoiding rainbow cliques of size four

A balanced edge-coloring of the complete graph is an edge-coloring such that every vertex is incident to each color the same number of times. In this short note, we present a construction of a balanced edge-coloring with six colors of the complete graph on $n=13^k$ vertices, for every positive integer $k$, with no rainbow $K_4$. This solves a problem by Erd\H{o}s and Tuza.Comment: 2 page