@inproceedings{40846, abstract = {{In this paper we characterize the capacity boundary of the two-user multiple-input multiple-output (MIMO) broadcast channel (BC) when the multiantenna terminals use analog beamforming at both sides of the link. Basically, the problem reduces to finding the optimal transmit direction and the optimal power allocation between users to operate at any point on the boundary. We show that both optimization problems can be solved in closed form. First, exploiting the fact that any Pareto optimal pair of rates must also be Pareto optimal of a convex region defined by the channel energies, the optimal transmit direction is shown to be the principal eigenvector of a matrix. Second, the optimal power allocation is obtained by exploiting again the Pareto optimality of the sought pair of rates. Although this paper focuses on the BC, the obtained results also serve to characterize the dual multiple-access channel (MAC). Moreover, this explicit characterization of the boundary can be extended to a $K$-user system for $K>2$. Numerical examples are provided to illustrate the results of the paper, and to show the enlargement of the capacity region achieved by analog beamforming in comparison to a single-input single-output (SISO) BC.}}, author = {{Santamaría, Ignacio and Vía, Javier and Nazábal, Alfredo and Lameiro, Christian}}, booktitle = {{Proc. Int. ICST Conf. Comm. and Networking in China}}, title = {{{Capacity region of the multiantenna Gaussian broadcast channel with analog TX-RX beamforming}}}, year = {{2010}}, } @article{18558, abstract = {{We present an implementation of the GW approximation for the electronic self-energy within the full-potential linearized augmented-plane-wave (FLAPW) method. The algorithm uses an all-electron mixed product basis for the representation of response matrices and related quantities. This basis is derived from the FLAPW basis and is exact for wave-function products. The correlation part of the self-energy is calculated on the imaginary-frequency axis with a subsequent analytic continuation to the real axis. As an alternative we can perform the frequency convolution of the Green function G and the dynamically screened Coulomb interaction W explicitly by a contour integration. The singularity of the bare and screened interaction potentials gives rise to a numerically important self-energy contribution, which we treat analytically to achieve good convergence with respect to the k-point sampling. As numerical realizations of the GW approximation typically suffer from the high computational expense required for the evaluation of the nonlocal and frequency-dependent self-energy, we demonstrate how the algorithm can be made very efficient by exploiting spatial and time-reversal symmetry as well as by applying an optimization of the mixed product basis that retains only the numerically important contributions of the electron-electron interaction. This optimization step reduces the basis size without compromising the accuracy and accelerates the code considerably. Furthermore, we demonstrate that one can employ an extrapolar approximation for high-lying states to reduce the number of empty states that must be taken into account explicitly in the construction of the polarization function and the self-energy. We show convergence tests, CPU timings, and results for prototype semiconductors and insulators as well as ferromagnetic nickel.}}, author = {{Friedrich, Christoph and Blügel, Stefan and Schindlmayr, Arno}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{12}}, publisher = {{American Physical Society}}, title = {{{Efficient implementation of the GW approximation within the all-electron FLAPW method}}}, doi = {{10.1103/PhysRevB.81.125102}}, volume = {{81}}, year = {{2010}}, } @article{45772, author = {{Herzel, Frank and Osmany, Sabbir A. and Scheytt, J. Christoph}}, journal = {{IEEE Transactions on Circuits and Systems I: Regular Papers}}, number = {{8}}, pages = {{1914--1924}}, title = {{{Analytical Phase-Noise Modeling and Charge Pump Optimization for Fractional-$N$ PLLs}}}, volume = {{57}}, year = {{2010}}, } @article{18560, abstract = {{We present a computational scheme to study spin excitations in magnetic materials from first principles. The central quantity is the transverse spin susceptibility, from which the complete excitation spectrum, including single-particle spin-flip Stoner excitations and collective spin-wave modes, can be obtained. The susceptibility is derived from many-body perturbation theory and includes dynamic correlation through a summation over ladder diagrams that describe the coupling of electrons and holes with opposite spins. In contrast to earlier studies, we do not use a model potential with adjustable parameters for the electron-hole interaction but employ the random-phase approximation. To reduce the numerical cost for the calculation of the four-point scattering matrix we perform a projection onto maximally localized Wannier functions, which allows us to truncate the matrix efficiently by exploiting the short spatial range of electronic correlation in the partially filled d or f orbitals. Our implementation is based on the full-potential linearized augmented-plane-wave method. Starting from a ground-state calculation within the local-spin-density approximation (LSDA), we first analyze the matrix elements of the screened Coulomb potential in the Wannier basis for the 3d transition-metal series. In particular, we discuss the differences between a constrained nonmagnetic and a proper spin-polarized treatment for the ferromagnets Fe, Co, and Ni. The spectrum of single-particle and collective spin excitations in fcc Ni is then studied in detail. The calculated spin-wave dispersion is in good overall agreement with experimental data and contains both an acoustic and an optical branch for intermediate wave vectors along the [100] direction. In addition, we find evidence for a similar double-peak structure in the spectral function along the [111] direction. To investigate the influence of static correlation we finally consider LSDA+U as an alternative starting point and show that, together with an improved description of the Fermi surface, it yields a more accurate quantitative value for the spin-wave stiffness constant, which is overestimated in the LSDA.}}, author = {{Şaşıoğlu, Ersoy and Schindlmayr, Arno and Friedrich, Christoph and Freimuth, Frank and Blügel, Stefan}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{5}}, publisher = {{American Physical Society}}, title = {{{Wannier-function approach to spin excitations in solids}}}, doi = {{10.1103/PhysRevB.81.054434}}, volume = {{81}}, year = {{2010}}, } @phdthesis{25872, author = {{Mahajan, Kiran}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{A combined simulation and optimization based method for predictive-reactive scheduling of flexible production systems subject to execution exceptions}}}, volume = {{263}}, year = {{2009}}, } @article{26893, author = {{Shi, Lijie and Wudy, Stefan A and Buyken, Anette and Hartmann, Michaela F and Remer, Thomas}}, issn = {{0002-9165}}, journal = {{The American Journal of Clinical Nutrition}}, pages = {{1321--1328}}, title = {{{Body fat and animal protein intakes are associated with adrenal androgen secretion in children}}}, doi = {{10.3945/ajcn.2009.27964}}, year = {{2009}}, } @article{26894, author = {{Karaolis-Danckert, Nadina and Buyken, Anette and Sonntag, Antje and Kroke, Anja}}, issn = {{0002-9165}}, journal = {{The American Journal of Clinical Nutrition}}, pages = {{1559--1565}}, title = {{{Birth and early life influences on the timing of puberty onset: results from the DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) Study}}}, doi = {{10.3945/ajcn.2009.28259}}, year = {{2009}}, } @article{26895, author = {{Cheng, Guo and Gerlach, Steffi and Libuda, Lars and Kranz, Sibylle and Günther, Anke L. B. and Karaolis-Danckert, Nadina and Kroke, Anja and Buyken, Anette}}, issn = {{1541-6100}}, journal = {{The Journal of Nutrition}}, pages = {{95--102}}, title = {{{Diet Quality in Childhood Is Prospectively Associated with the Timing of Puberty but Not with Body Composition at Puberty Onset}}}, doi = {{10.3945/jn.109.113365}}, year = {{2009}}, } @article{26896, author = {{Günther, Anke L. B. and Karaolis-Danckert, Nadina and Kroke, Anja and Remer, Thomas and Buyken, Anette}}, issn = {{1541-6100}}, journal = {{The Journal of Nutrition}}, pages = {{565--571}}, title = {{{Dietary Protein Intake throughout Childhood Is Associated with the Timing of Puberty}}}, doi = {{10.3945/jn.109.114934}}, year = {{2009}}, } @article{27008, author = {{Buyken, Anette and Flood, Victoria and Rochtchina, Elena and Nestel, Paul and Brand-Miller, Jennie and Mitchell, Paul}}, issn = {{1541-6100}}, journal = {{The Journal of Nutrition}}, pages = {{88--94}}, title = {{{Modifications in Dietary Fat Quality Are Associated with Changes in Serum Lipids of Older Adults Independently of Lipid Medication}}}, doi = {{10.3945/jn.109.110486}}, year = {{2009}}, } @article{27080, author = {{Muckelbauer, Rebecca and Libuda, Lars and Clausen, Kerstin and Toschke, André M. and Reinehr, Thomas and Kersting, Mathilde}}, issn = {{1930-7381}}, journal = {{Obesity}}, pages = {{528--534}}, title = {{{Immigrational Background Affects the Effectiveness of a School-based Overweight Prevention Program Promoting Water Consumption}}}, doi = {{10.1038/oby.2009.270}}, year = {{2009}}, } @article{27132, abstract = {{AbstractObjectiveDrinking habits in children are associated with diet quality, but validated assessment tools for large-scale studies in young children are lacking. Therefore, we validated a self-completion 24 h recall questionnaire (RQ) focusing on beverage consumption with a 24 h weighed record (WR).DesignThirty-five voluntary participants from the DONALD (Dortmund Nutritional and Anthropometric Longitudinally Designed) Study cohort aged 7–9 years completed the RQ. The illustrated RQ required ticking the number of glasses of seven beverage categories consumed in five time intervals in the previous 24 h. As a reference, parents completed weighed records of their child’s diet. Agreement between the RQ and WR was tested by classification into consumers and non-consumers (kappa coefficients, κ), by the children’s ability to estimate the exact beverage and total volume consumed (Wilcoxon signed-rank test, Spearman rank correlation), and by ranking children according to reported beverage volumes.ResultsThe RQ and WR showed a good level of agreement for classifying participants into consumers and non-consumers of the single beverage categories (κ values between 0·78 and 0·94). Correlation coefficients for the volume of the single categories ranged between 0·81 and 0·91. The total beverage volume was overestimated in the RQ, on average, by 114 ml (P = 0·015). Agreement in ranking into tertiles by beverage volume was moderate to good for juice/soft drinks (κ = 0·44), milk (κ = 0·57) and water (κ = 0·70), but fair for the total beverage volume (κ = 0·23).ConclusionsOur self-completion 24 h RQ could estimate the consumption of several beverage categories among young children at the group level, but quantification of total beverage volume was flawed.}}, author = {{Muckelbauer, Rebecca and Libuda, Lars and Kersting, Mathilde}}, issn = {{1368-9800}}, journal = {{Public Health Nutrition}}, pages = {{187--195}}, title = {{{Relative validity of a self-completion 24 h recall questionnaire to assess beverage consumption among schoolchildren aged 7 to 9 years}}}, doi = {{10.1017/s1368980009990759}}, year = {{2009}}, } @article{27133, author = {{Cheng, G. and Karaolis-Danckert, N. and Libuda, Lars and Bolzenius, K. and Remer, T. and Buyken, Anette E.}}, issn = {{0002-9262}}, journal = {{American Journal of Epidemiology}}, pages = {{667--677}}, title = {{{Relation of Dietary Glycemic Index, Glycemic Load, and Fiber and Whole-Grain Intakes During Puberty to the Concurrent Development of Percent Body Fat and Body Mass Index}}}, doi = {{10.1093/aje/kwn375}}, year = {{2009}}, } @article{27134, author = {{Muckelbauer, R. and Libuda, Lars and Clausen, K. and Kersting, M.}}, issn = {{0305-1862}}, journal = {{Child: Care, Health and Development}}, pages = {{851--857}}, title = {{{Long-term process evaluation of a school-based programme for overweight prevention}}}, doi = {{10.1111/j.1365-2214.2009.00993.x}}, year = {{2009}}, } @article{27135, author = {{Muckelbauer, Rebecca and Libuda, Lars and Clausen, Kerstin and Reinehr, Thomas and Kersting, Mathilde}}, issn = {{1662-4033}}, journal = {{Obesity Facts}}, pages = {{282--285}}, title = {{{A Simple Dietary Intervention in the School Setting Decreased Incidence of Overweight in Children}}}, doi = {{10.1159/000229783}}, year = {{2009}}, } @article{27136, author = {{Muckelbauer, R. and Libuda, Lars and Clausen, K. and Toschke, A. M. and Reinehr, T. and Kersting, M.}}, issn = {{0031-4005}}, journal = {{PEDIATRICS}}, pages = {{e661--e667}}, title = {{{Promotion and Provision of Drinking Water in Schools for Overweight Prevention: Randomized, Controlled Cluster Trial}}}, doi = {{10.1542/peds.2008-2186}}, year = {{2009}}, } @article{27525, author = {{Libuda, Lars and Kersting, Mathilde}}, issn = {{1363-1950}}, journal = {{Current Opinion in Clinical Nutrition and Metabolic Care}}, pages = {{596--600}}, title = {{{Soft drinks and body weight development in childhood: is there a relationship?}}}, doi = {{10.1097/mco.0b013e32833189f6}}, year = {{2009}}, } @article{27583, author = {{Libuda, Lars and Muckelbauer, R. and Kersting, M.}}, journal = {{Journal für Ernährungsmedizin}}, pages = {{23}}, title = {{{Getränkeverzehr und Übergewicht bei Kindern}}}, volume = {{11}}, year = {{2009}}, } @article{27584, author = {{Libuda, Lars}}, journal = {{Ernährungsumschau}}, number = {{8}}, pages = {{480--481}}, title = {{{Einfluss des Konsums von Erfrischungsgetränken auf den Ernährungs- und Gesundheits¬status von Kindern}}}, volume = {{56}}, year = {{2009}}, } @article{27585, author = {{Libuda, Lars and Remer, Thomas and Kersting, M.}}, journal = {{Ernährungsumschau}}, number = {{3}}, pages = {{137}}, title = {{{DONALD News: Zusammenhang zwischen dem Verzehr von Erfrischungsgetränken und dem Knochenstatus von Kindern und Jugendlichen. }}}, volume = {{56}}, year = {{2009}}, }