Einträgerübertragung mit Frequenzbereichsentzerrung - Erweiterung für Mehrantennensysteme, Synchronisationskonzepte und experimentelle Verifikation -

Driven by the human desideratum for communication and social interaction, the field of mobile communications has undergone an enormous boom in the last years. Initialized by the mobile telephony and the internet, existing systems evolutionized and new systems have been developed whereas criteria as media convergence and quality of service have become more and more important. These paradigms as well as the requirement to serve different standards and applications with a single integrative system approach demand powerful and flexible solutions, which can provide highest data rates, but are smaller, operate energy-saving and can be produced economically. Two essential problems have to be solved for high data rate digital communication systems: The first obstacle is the multipath propagation, which causes a distortion of the transmitted signal, the second problem is the limitation of transmit energy and bandwidth because of regulatory and legal licensing restrictions. One possibility to solve the problem of multipath propagation is the application of equalizers, exspecially of frequency domain equalizers, that will be the focus of this work. This thesis is structured as follows: In chapter 2 the fundametals of digital communications as far as needed for this work will be summarized. Chapter 3 contains a survey about important channel characteristics and channel parameters the subsequent simulations are based on. In chapter 4 equalizers, exspecially the frequency domain equalizers (FDE), that can be implemented with a lower complexity as the time domain equalizers if the number of digitally solvable paths exceed a certain limit, will be investigated for single carrier systems. Not only the classical receiver-side concepts will be analytically described, but also predistortion techniques and combinations of both will be investigated. The second problem can be solved by the use of multi-antenna systems. These systems have been from growing interests in the last few years because of the analytical fact, that the channel capacity is linearily growing with the number of antennas and transmit paths. Multi-antenna systems allow higher data rates or decreasing requirements for the signal to noise relation without increasing bandwidth or transmit energy. In chapter 5 different methods for exploiting multi-antenna systems will be described and adapted to SC/FDE. In detail, maximum ratio combining (MRC) as a trasmit diversity approach, space time block coding (STBC) as a receive diversity method as well as spatial multiplexing as a space diversity approach will be explained. The spacial multiplexing system will be expanded by the optimal matched filter and successive interference cancellation (SIC), which is an approach known from multiuser detection. viii Chapter 6 contains the development of a data aided synchronization concept. This concept should comprise all incidental synchronization tasks, like automatic gain control (AGC), frame synchronization, carrier frequency offset (CFO) estimation and channel estimation for burst-oriented systems. This chapter forms the necessary substructure for the third and last emphasis of this thesis, the development of a demonstrator system to verify the basic functions of the SC/FDE system. The design of this demonstrator will be elucidated in the first part of chapter 7, followed by specific informations about used components and self-constructed modules. All used hardware and software interfaces will be mentioned shortly, without substituting the manuals or documentation. Some measurement results conclude this chapter as well as the thesis. Based on the underlying investigations and simulation results it can be concluded that the SC/FDE system shows a comparable complexity in contrast to competing approaches like Orthogonal Frequency Division Multiplexing (OFDM) and additionally features some significant advantages for example the better peak to average power ration (PARP). On the one hand SC/FDE represents an alternative to OFDM and can on the other hand contribute in combination with OFDM and resulting synergetic effects to make future systems faster, more flexible and economic.Angetrieben vom menschlichen Bedürfnis nach Kommunikation und sozialer Interaktion hat der Mobilkommunikationssektor in den letzten Jahren einen unglaublichen Aufschwung erfahren. Initiiert durch die mobile Sprachkommunikation und das Internet evolutionierten sich zum einen bestehende Systeme in den letzten Jahren immer weiter und zum anderen entstanden zahlreiche neue Systeme. Schlagwörtern wie Medienkonvergenz und Quality of Service wurde hierbei steigende Beachtung geschenkt. Diese Paradigmen, sowie der Wunsch unterschiedliche Standards und Anwendungen durch einen einzigen integrativen Systemansatz zu bedienen, verlangen nach leistungsfähigeren und flexibleren Systemen, die höchste Datenraten zur Verfügung stellen, aber trotzdem kleiner sind, energiesparender arbeiten und wirtschaftlicher produzierbar sind. Zwei wesentliche Problemstellungen müssen für die Konzeption hochbitratiger drahtloser digitaler Kommunikationssysteme gelöst werden. Erste Hürde ist die so genannte Mehrwegeausbreitung, die eine Verzerrung des Übertragungssignals verursacht, zweites Problem ist die Begrenzung der Bandbreite und Sendeenergie durch behördliche und lizenzrechtliche Restriktionen. Eine Möglichkeit, das Problem der Mehrwegeausbreitung zu lösen, bietet der Einsatz von Entzerrern, insbesondere von Frequenzbereichsentzerrern, die in dieser Arbeit Gegenstand sein werden. Die Arbeit ist folgendermaÿen gegliedert: In Kapitel 2 werden die Grundlagen der digitale Übertragungstechnik, soweit sie fürdiese Arbeit von Relevanz sind, zusammengefasst. Kapitel 3 enthält eine Übersicht über die wichtigsten Kanaleigenschaften und Kanalkenngrößen, die für die nachfolgenden Simulationen als Basis dienen. In Kapitel 4 werden Entzerrer, insbesondere Realisierungen im Frequenzbereich (FDE: Frequency Domain Equalization) für Einträgersysteme (SC: Single Carrier) untersucht. Die Frequenzbereichsentzerrung bietet ab einer bestimmten Anzahl an im digitalen Signal auflösbaren Ausbreitungspfaden einen signifikanten Komplexitätsvorteil. Dabei werden nicht nur die klassischen empfängerseitigen Konzepte analytisch beschrieben, sondern auch Vorverzerrer und kombinierte Verfahren untersucht. Der Einsatz von Mehrantennensystemen liefert den Schlüssel zur Lösung des zweiten Problems. Diesen Systemen ist in den letzten Jahren ein stetig wachsendes Interesse entgegengebracht worden, da analytisch gezeigt werden konnte, dass die Kanalkapazität linear mit der Zahl der Antennen und der Zahl der Ausbreitungspfade steigt. Dank dieses Verfahrens können höhere Datenraten bzw. geringere Anforderungen an das Signal-Störleistungsverhältnis ohne eine Erhöhung der Sendeleistung oder der Bandbreite realisiert werden. In Kapitel 5 werden verschiedene relevante Prinzipien solcher Mehrantennensysteme beschrieben und für das SC/FDE-System adaptiert. Im Detail werden Maximum Ratio Combining (MRC) als Konzept zur Nutzung der Empfangsdiversität, Space-Time Block Coding (STBC) nach dem erweiterten Alamouti-Prinzip zur Nutzung von Sendediversität, sowie Spatial Multiplexing (SM) zur Nutzung der gesamten Raumdiversität vorgestellt. Das SM-Verfahren wird in dieser Arbeit durch das optimale kanalangepasste Matched-Filter sowie durch ein aus der Mehrnutzerdetektion bekanntes Verfahren, der sukzessiven Interferenzunterdrückung (SIC: Successive Interference Cancelation), erweitert. Kapitel 6 hat die Entwicklung eines datengestützten Konzepts zum Inhalt, mit dem alle anfallenden Synchronisationsaufgaben, wie Automatic Gain Control (AGC), Rahmensynchronisation, Schätzung der Trägerfrequenzablage und Kanalschätzung, für paketorientierte Systeme ausgeführt werden können. Kapitel 6 bildet zugleich eine notwendige Grundlage für den dritten und letzten Schwerpunkt dieser Arbeit: der Entwicklung eines Demonstratorsystems, mit dem die prinzipielle Funktion des SC/FDE-Systems verifiziert wird. Die Konzeption dieses Demonstrators wird im ersten Teil des Kapitel 7 ausführlich erläutert. Es folgen weitergehende Beschreibungen der verwendeten Komponenten und Bauteile sowie der selbst entwickelten Module. Alle verwendeten Hard- und Software-Schnittstellen werden kurz vorgestellt, wobei die Darstellungen jedoch nicht als Ersatz für ein Datenblatt oder für die zugehörigen Dokumentationen dienen sollen. Messergebnisse runden dieses Kapitel und die Arbeit ab. Im Rahmen dieser Dissertation wird analytisch und simulativ gezeigt, dass das untersuchte SC/FDE-System eine vergleichbare Komplexität gegenüber konkurrierenden Verfahren wie Orthogonal Frequency Division Multiplexing (OFDM) aufweist und zusätzlich signifikante Vorteile, wie das bessere Peak to Average Power Ratio (PARP), bietet. SC/FDE stellt nicht nur eine echte Alternative zu OFDM-Systemen dar, sondern kann in Kombination mit OFDM durch Synergieeffekte dazu beitragen, zukünftige Systeme schneller, fexibler und kostengünstiger zu machen

Neural networks for impact parameter determination

Accurate impact parameter determination in a heavy-ion collision is crucial for almost all further analysis. We investigate the capabilities of an artificial neural network in that respect. First results show that the neural network is capable of improving the accuracy of the impact parameter determination based on observables such as the flow angle, the average directed inplane transverse momentum and the difference between transverse and longitudinal momenta. However, further investigations are necessary to discover the full potential of the neural network approach

Primicimex cavernis Barber 1941 (Heteroptera: Cimicidae): A rare parasite on a very abundant host

Species richness and abundance of hosts and parasites are often not perfectly correlated. This may be caused by higher parasite than host extinction rates or population declines, but lower parasite discovery effort has also been suggested. The Mexican free-tailed bat Tadarida brasiliensis is one of the most common and widespread vertebrates in the Americas and host to the ectoparasite Primicimex cavernis, for which only 14 literature records from six sites worldwide exist. Here, we confirm a much smaller parasite than host range. Two dedicated field trips revealed two new P. cavernis sites. In Texas, we found 87% out of eight sites negative for P. cavernis. However, this more likely reflects rarity than low discovery effort, because in one large population (>1000 individuals) in Sonora, putatively negative records occurred at only 31% of 16 sampling dates. Currently, live individuals of P. cavernis are known from only one cave in the United States and one in Mexico. Protecting these existing sites is necessary to preserve this charismatic animal but it should not release us from aiming to discover new sites.publishedVersio

Protein disulfide isomerase acts as an injury response signal that enhances fibrin generation via tissue factor activation

The activation of initiator protein tissue factor (TF) is likely to be a crucial step in the blood coagulation process, which leads to fibrin formation. The stimuli responsible for inducing TF activation are largely undefined. Here we show that the oxidoreductase protein disulfide isomerase (PDI) directly promotes TF-dependent fibrin production during thrombus formation in vivo. After endothelial denudation of mouse carotid arteries, PDI was released at the injury site from adherent platelets and disrupted vessel wall cells. Inhibition of PDI decreased TF-triggered fibrin formation in different in vivo murine models of thrombus formation, as determined by intravital fluorescence microscopy. PDI infusion increased — and, under conditions of decreased platelet adhesion, PDI inhibition reduced — fibrin generation at the injury site, indicating that PDI can directly initiate blood coagulation. In vitro, human platelet–secreted PDI contributed to the activation of cryptic TF on microvesicles (microparticles). Mass spectrometry analyses indicated that part of the extracellular cysteine 209 of TF was constitutively glutathionylated. Mixed disulfide formation contributed to maintaining TF in a state of low functionality. We propose that reduced PDI activates TF by isomerization of a mixed disulfide and a free thiol to an intramolecular disulfide. Our findings suggest that disulfide isomerases can act as injury response signals that trigger the activation of fibrin formation following vessel injury

Physical activity in 9–15 year-old pediatric cancer survivors compared to a nationwide sample

Introduction: Sufficient physical activity (PA) has the potential to mitigate late effects of cancer, but objective data of PA levels in adolescents are scarce. The aim of this study was to investigate differences in PA behavior between childhood cancer survivors (CCS) and healthy peers. Methods: PA levels of n = 74 CCS and n = 1304 healthy peers from the MoMo study aged 9–15 years were assessed with validated objective accelerometry and group means were compared. A binary multiple logistic regression was performed to investigate the potential predictors of PA. Results: CCS spent significantly more time sedentary (p < 0.001) and less time in moderate-to-vigorous physical activity (p = 0.002) compared to the healthy cohort. Subgroup analysis revealed the largest deviations of PA levels for CCS aged 9–11 years who fulfilled international PA recommendations on significantly fewer days than MoMo (p < 0.01). Health conditions seem to be a predictor concerning the fulfillment of international PA recommendations by the WHO (p = 0.015). Conclusions: Our study identified vulnerable groups which seem to require targeted exercise and health behavior change programs to increase physical activity and reduce sedentary time. The presence of treatment sequelae as a significant predictor of insufficient physical activity underlines the need of multidisciplinary supportive care approaches

Generation, Annotation, Evolutionary Analysis, and Database Integration of 20,000 Unique Sea Urchin EST Clusters

Together with the hemichordates, sea urchins represent basal groups of nonchordate invertebrate deuterostomes that occupy a key position in bilaterian evolution. Because sea urchin embryos are also amenable to functional studies, the sea urchin system has emerged as one of the leading models for the analysis of the function of genomic regulatory networks that control development. We have analyzed a total of 107,283 cDNA clones of libraries that span the development of the sea urchin Strongylocentrotus purpuratus. Normalization by oligonucleotide fingerprinting, EST sequencing and sequence clustering resulted in an EST catalog comprised of 20,000 unique genes or gene fragments. Around 7000 of the unique EST consensus sequences were associated with molecular and developmental functions. Phylogenetic comparison of the identified genes to the genome of the urochordate Ciona intestinalis indicate that at least one quarter of the genes thought to be chordate specific were already present at the base of deuterostome evolution. Comparison of the number of gene copies in sea urchins to those in chordates and vertebrates indicates that the sea urchin genome has not undergone extensive gene or complete genome duplications. The established unique gene set represents an essential tool for the annotation and assembly of the forthcoming sea urchin genome sequence. All cDNA clones and filters of all analyzed libraries are available from the resource center of the German genome project at http://www.rzpd.de

Polo-like kinase 3 regulates CtIP during DNA double-strand break repair in G1

DNA double-strand breaks (DSBs) are repaired by nonhomologous end joining (NHEJ) or homologous recombination (HR). The C terminal binding protein–interacting protein (CtIP) is phosphorylated in G2 by cyclin-dependent kinases to initiate resection and promote HR. CtIP also exerts functions during NHEJ, although the mechanism phosphorylating CtIP in G1 is unknown. In this paper, we identify Plk3 (Polo-like kinase 3) as a novel DSB response factor that phosphorylates CtIP in G1 in a damage-inducible manner and impacts on various cellular processes in G1. First, Plk3 and CtIP enhance the formation of ionizing radiation-induced translocations; second, they promote large-scale genomic deletions from restriction enzyme-induced DSBs; third, they are required for resection and repair of complex DSBs; and finally, they regulate alternative NHEJ processes in Ku−/− mutants. We show that mutating CtIP at S327 or T847 to nonphosphorylatable alanine phenocopies Plk3 or CtIP loss. Plk3 binds to CtIP phosphorylated at S327 via its Polo box domains, which is necessary for robust damage-induced CtIP phosphorylation at S327 and subsequent CtIP phosphorylation at T847

Tip- and laser-based 3D nanofabrication in extended macroscopic working areas

The field of optical lithography is subject to intense research and has gained enormous improvement. However, the effort necessary for creating structures at the size of 20 nm and below is considerable using conventional technologies. This effort and the resulting financial requirements can only be tackled by few global companies and thus a paradigm change for the semiconductor industry is conceivable: custom design and solutions for specific applications will dominate future development (Fritze in: Panning EM, Liddle JA (eds) Novel patterning technologies. International society for optics and photonics. SPIE, Bellingham, 2021. https://doi.org/10.1117/12.2593229). For this reason, new aspects arise for future lithography, which is why enormous effort has been directed to the development of alternative fabrication technologies. Yet, the technologies emerging from this process, which are promising for coping with the current resolution and accuracy challenges, are only demonstrated as a proof-of-concept on a lab scale of several square micrometers. Such scale is not adequate for the requirements of modern lithography; therefore, there is the need for new and alternative cross-scale solutions to further advance the possibilities of unconventional nanotechnologies. Similar challenges arise because of the technical progress in various other fields, realizing new and unique functionalities based on nanoscale effects, e.g., in nanophotonics, quantum computing, energy harvesting, and life sciences. Experimental platforms for basic research in the field of scale-spanning nanomeasuring and nanofabrication are necessary for these tasks, which are available at the Technische Universität Ilmenau in the form of nanopositioning and nanomeasuring (NPM) machines. With this equipment, the limits of technical structurability are explored for high-performance tip-based and laser-based processes for enabling real 3D nanofabrication with the highest precision in an adequate working range of several thousand cubic millimeters

Reconstruction and control of a time-dependent two-electron wave packet

The concerted motion of two or more bound electrons governs atomic1 and molecular2,3 non-equilibrium processes including chemical reactions, and hence there is much interest in developing a detailed understanding of such electron dynamics in the quantum regime. However, there is no exact solution for the quantumthree-body problem, and as a result even the minimal system of two active electrons and a nucleus is analytically intractable4. This makes experimental measurements of the dynamics of two bound and correlated electrons, as found in the helium atom, an attractive prospect.However, although the motion of single active electrons and holes has been observed with attosecond time resolution5-7, comparable experiments on two-electron motion have so far remained out of reach. Here we showthat a correlated two-electron wave packet can be reconstructed froma 1.2-femtosecondquantumbeatamong low-lying doubly excited states in helium.The beat appears in attosecond transient-absorption spectra5,7-9 measured with unprecedentedly high spectral resolution and in the presence of an intensity-tunable visible laser field.Wetune the coupling10-12 between the two low-lying quantum states by adjusting the visible laser intensity, and use the Fano resonance as a phase-sensitive quantum interferometer13 to achieve coherent control of the two correlated electrons. Given the excellent agreement with large-scalequantum-mechanical calculations for thehelium atom, we anticipate thatmultidimensional spectroscopy experiments of the type we report here will provide benchmark data for testing fundamental few-body quantumdynamics theory in more complex systems. Theymight also provide a route to the site-specificmeasurement and control of metastable electronic transition states that are at the heart of fundamental chemical reactionsWe thank E. Lindroth for calculating the dipole moment (2p2|r|sp2,3+), and also A. Voitkiv, Z.-H. Loh, and R. Moshammer for helpful discussions. We acknowledge financial support by the Max-Planck Research Group Program of the Max-Planck Gesellschaft (MPG) and the European COST Action CM1204 XLIC. L. A. and F. M. acknowledge computer time from the CCC-UAM and Mare Nostrum supercomputer centers and financial support by the European Research Council under the ERC Advanced Grant no. 290853 XCHEM, the Ministerio de Economía y Competitividad projects FIS2010-15127, FIS2013-42002-R and ERA-Chemistry PIM2010EEC-00751, and the European grant MC-ITN CORIN