Power-Based Direction-of-Arrival Estimation Using a Single Multi-Mode Antenna

Phased antenna arrays are widely used for direction-of-arrival (DoA) estimation. For low-cost applications, signal power or received signal strength indicator (RSSI) based approaches can be an alternative. However, they usually require multiple antennas, a single antenna that can be rotated, or switchable antenna beams. In this paper we show how a multi-mode antenna (MMA) can be used for power-based DoA estimation. Only a single MMA is needed and neither rotation nor switching of antenna beams is required. We derive an estimation scheme as well as theoretical bounds and validate them through simulations. It is found that power-based DoA estimation with an MMA is feasible and accurate

Unraveling the functional contribution of Fkbp5 to stress vulnerability

Trotz jahrzehntelanger Bemühungen gibt es noch immer eine Vielzahl psychiatrischer Erkrankungen, für die uns keine effektiven Behandlungsmöglichkeiten zur Verfügung stehen. Da wir den Einfluss unserer Umwelt auf die psychische Gesundheit nur zu einem gewissen Grad beeinflussen können, ist die Identifikation von Risikogenen für eben solche Krankheiten besonders wichtig. Einer der Kandidaten, der in den letzten Jahren große Beachtung gefunden hat ist dabei das FKBP5-Gen, welches beim Menschen in starker Verbindung zu Depression oder Posttraumatischer Belastungsstörung steht. FKBP5 ist ein wichtiger Regulator für die Ausschüttung von Stress-Hormonen und an essenzieller Stelle in den molekularen Signalweg der körpereigenen Stressantwort eingebunden. Um unser Verständnis des Gens zu erweitern, habe ich im Rahmen dieser Arbeit eine weitreichende Charakterisierung verschiedener Mausmodelle durchgeführt. Dabei konnte ich zwei monoaminerge Regionen im Gehirn identifizieren, die eine sehr hohe Grundexpression des Gens aufweisen und in denen Fkbp5 stressabhängig reguliert wird. Sowohl virale Überexpression, als auch das genetische Ausschalten des Gens hatten Veränderungen im Verhalten und der hormonellen Stressantwort der Tiere zur Folge. Im nächsten Schritt habe ich SAFit2, einen spezifischen Antagonisten für Fkbp5, eingesetzt und konnte dabei wieder Veränderungen im Verhalten und der endokrinen Reaktion auf einen externen Stressor beobachten. Auch die Kombination mit einem etablierten Antidepressivum hatte verhaltensbasierte Auswirkungen und sollte in zukünftigen Untersuchungen noch erweitert werden. Im Rahmen meiner Versuche konnte ich zudem einen erheblichen Beitrag zur Entwicklung und Erprobung neuer Applikationsmöglichkeiten von chemischen Substanzen leisten. Dabei habe ich eine Reihe von in vivo Tests mit einem neu entwickelten, Gel-basierten Trägerstoff für SAFit2 durchgeführt. Insgesamt bilden die Ergebnisse dieser Arbeit eine hervorragende Basis für die weitere Erprobung von Fkbp5-basierten Behandlungsmethoden. Die Manipulation von FKBP5 ist immer noch eine vielversprechende Alternative zu etablierten Behandlungsmethoden für psychiatrische Erkrankungen

Cooperative Position and Orientation Estimation with Multi-Mode Antennas

Robotic multi-agent systems are envisioned for planetary exploration and terrestrial applications. Autonomous operation of robots requires estimations of their positions and orientations, which are obtained from the direction-of-arrival (DoA) and the time-of-arrival (ToA) of radio signals exchanged among the agents. In this thesis, we estimate the signal DoA and ToA using a multi-mode antenna (MMA). An MMA is a single antenna element, where multiple orthogonal current modes are excited by different antenna ports. We provide a first study on the use of MMAs for cooperative position and orientation estimation, specifically exploring their DoA estimation capabilities. Assuming the agents of a cooperative network are equipped with MMAs, lower bounds on the achievable position and orientation accuracy are derived. We realize a gap between the theoretical lower bounds and real-world performance of a cooperative radio localization system, which is caused by imperfect antenna and transceiver calibration. Consequentially, we theoretically analyze in-situ antenna calibration, introduce an algorithm for the calibration of arbitrary multiport antennas and show its effectiveness by simulation. To also improve calibration during operation, we propose cooperative simultaneous localization and calibration (SLAC). We show that cooperative SLAC is able to estimate antenna responses and ranging biases of the agents together with their positions and orientations, leading to considerably better position and orientation accuracy. Finally, we validate the results from theory and simulation by experiments with robotic rovers equipped with software-defined radios (SDRs). In conclusion, we show that DoA estimation with an MMA is feasible, and accuracy can be improved by in-situ calibration and SLAC

“I Just Look at Books”: Reading the Monetary Metareality of Bleeding Edge

The essay analyzes 'Bleeding Edg'e for its pervasive representation of money, arguing that it operates as a metareality in the novel both on the levels of plot and style. Money is presented as a symbolic structure behind reality that is accessible to the initiated, the interpretation of which offers genuine insight about the world and its interrelations, in parallel to religious or scientific discourses. This does not simply mean that everything—politics, society, culture, technology, etc.—is ultimately determined by economic factors, but rather that money underlies the reality of these phenomena like a kind of source code, and that it is readable as such, for better or worse. In the novel, real and virtual money is heavily associated with moral values and their loss, although it is not at all only associated negatively with greed and the abuse of power. Money also harbors subversive potential in 'Bleeding Edge', as it can uncover corruption and fraud as much as other conspiratorial phenomena (especially in connection to 9/11). In particular, cash money can become an alternative medium of communication that combines the private and the public. Money does exhibit a tendency towards moral corruption in the novel, but at the same time it eludes any complete control and remains an economic as well as symbolic tool that can undermine the very capitalist system it seems to perpetuate

Local adaptation in the presence of gene flow in Patagonian and Antarctic Nacella limpets: a multimarker genetic and physiological approach

The understanding of how speciation works in the ocean has always challenged marine biologists because the marine realm is characterized by the absence of strict barriers to gene flow over large geographical scales. The impact of natural selection as a source of speciation in the marine system has also been considered to be low because of the very high gene flow overriding the effects of locally varying selective pressures. In a top-down approach I analyzed large-scale impacts of emerging geographical barriers and small-scale influences of biogeographic patterning and local adaptations on the evolutionary history of Antarctic and South American Nacella limpets. A large set of genetic and physiological, neutral and selected markers was applied. The results show that natural selection and local adaptation are much more important drivers of marine speciation than previously believed. The application of genetic markers under selection revealed how natural selection is capable to maintain adaptive divergence in parts of a genome to ensure adaptability to environmental constraints even in high gene flow environments

Modelling Aspects of Planar Multi-Mode Antennas for Direction-of-Arrival Estimation

Multi-mode antennas are an alternative to classical antenna arrays, and hence a promising emerging sensor technology for a vast variety of applications in the areas of array signal processing and digital communications. An unsolved problem is to describe the radiation pattern of multi-mode antennas in closed analytic form based on calibration measurements or on electromagnetic field (EMF) simulation data. As a solution, we investigate two modeling methods: One is based on the array interpolation technique (AIT), the other one on wavefield modeling (WM). Both methods are able to accurately interpolate quantized EMF data of a given multi-mode antenna, in our case a planar four-port antenna developed for the 6-8.5 GHz range. Since the modeling methods inherently depend on parameter sets, we investigate the influence of the parameter choice on the accuracy of both models. Furthermore, we evaluate the impact of modeling errors for coherent maximum-likelihood direction-of-arrival (DoA) estimation given different model parameters. Numerical results are presented for a single polarization component. Simulations reveal that the estimation bias introduced by model errors is subject to the chosen model parameters. Finally, we provide optimized sets of AIT and WM parameters for the multi-mode antenna under investigation. With these parameter sets, EMF data samples can be reproduced in interpolated form with high angular resolution

On Robust Sequential Analysis - Kiefer-Weiss Optimal Testing under Interval Probability

Usual sequential testing procedures often are very sensitive against even small deviations from the `ideal model' underlying the hypotheses. This makes robust procedures highly desirable. To rely on a clearly defined optimality criterion, we incorporate robustness aspects directly into the formulation of the hypotheses considering the problem of sequentially testing between two interval probabilities (imprecise probabilities). We derive the basic form of the Kiefer-Weiss optimal testing procedure and show how it can be calculated by an easy-to-handle optimization problem. These results are based on the reinterpretation of our testing problem as the task to test between nonparametric composite hypotheses, which allows to adopt the framework of Pavlov (1991). From this we obtain a general result applicable to any interval probability field on a finite sample space, making the approach powerful far beyond robustness considerations, for instance for applications in artificial intelligence dealing with imprecise expert knowledge

A system for production of defective interfering particles in the absence of infectious influenza A virus

<div><p>Influenza A virus (IAV) infection poses a serious health threat and novel antiviral strategies are needed. Defective interfering particles (DIPs) can be generated in IAV infected cells due to errors of the viral polymerase and may suppress spread of wild type (wt) virus. The antiviral activity of DIPs is exerted by a DI genomic RNA segment that usually contains a large deletion and suppresses amplification of wt segments, potentially by competing for cellular and viral resources. DI-244 is a naturally occurring prototypic segment 1-derived DI RNA in which most of the PB2 open reading frame has been deleted and which is currently developed for antiviral therapy. At present, coinfection with wt virus is required for production of DI-244 particles which raises concerns regarding biosafety and may complicate interpretation of research results. Here, we show that cocultures of 293T and MDCK cell lines stably expressing codon optimized PB2 allow production of DI-244 particles solely from plasmids and in the absence of helper virus. Moreover, we demonstrate that infectivity of these particles can be quantified using MDCK-PB2 cells. Finally, we report that the DI-244 particles produced in this novel system exert potent antiviral activity against H1N1 and H3N2 IAV but not against the unrelated vesicular stomatitis virus. This is the first report of DIP production in the absence of infectious IAV and may spur efforts to develop DIPs for antiviral therapy.</p></div

Einfluss des Sagittalen Profils der Wirbelsäule bei Patienten mit lumbaler Spinalkanalstenose auf das postoperative Resultat nach mikrochirurgischer Dekompression

Die mikrochirurgische Dekompression ist eine etablierte Operation für die Behandlung von Patienten mit einer lumbalen Spinalkanalstenose. Das klinische Resultat der Operation ist gut. Jedoch erfahren 30-40% der Patienten keine signifikante Besserung der Beschwerden postoperativ. Die Gründe hierfür sind unklar. Angenommen wird ein Zusammenhang mit den individuellen anatomischen Gegebenheiten der Patienten. Die unterschiedlichen Typen des Sagittalen Profils wurden von Roussouly definiert (Typ 1-4) und spielen bei unterschiedlichen Krankheitsbildern eine wichtige Rolle. Der Einfluss des Sagittalen Profils auf Patienten, die eine mikrochirurgische Dekompression der lumbalen Spinalkanalstenose erhalten haben, wurde bisher nicht erforscht und sollte in dieser Studie als Einflussfaktor auf das klinische Resultat untersucht werden.OBJETICVE The microsurgical decompression for patients with symptomatic lumbar spinal stenosis is a well-established surgery. In general, the operation shows a good clinical outcome. However, 30-40% of patients do not benefit after surgical decompression. This could be related to different anatomical preconditions of the patients. Well-known anatomical parameters are the sagittal profile types defined by Roussouly. There are four sagittal profile types (SPT 1-4), which are defined due to their spinopelvic parameters. The sagittal profile types have already been shown to influence in the surgical results in degenerative disc disease. In our study we investigated the influence of the sagittal profile type in patients, who suffered from lumbar spinal stenosis and received a microsurgical decompression. METHODS One hundred patients were analyzed retrospectively. All of them suffered from symptomatic lumbar spinal stenosis and were treated via a microsurgical decompression. Preoperative lateral spinal radiographs were performed. Patients were assigned to one of four groups according to their sagittal profile type. Furthermore, pre- and postoperative outcome scales, including the walking distance, visual analog scale (VAS), Roland-Morris Disability Questionnaire, Oswestry Disability Index, Odom’s criteria and the 36-Item Short-Form Health Survey score (SF-36) were analyzed. RESULTS 70-80% of the patients with sagittal profile type 2-4 were satisfied with the surgical results after microsurgical decompression. However, only 43% of the patients with sagittal profile type 1 were satisfied. This is reflected in significant worse clinical outcome scores concerning their back-pain related disability and postoperative back pain (VASback-SPT 1 = 5.4 ± 2.8; VASback-SPT 2 = 2.6 ± 1.9; VASback-SPT 3 = 2.9 ± 2.6; VASback-SPT 4 = 1.5 ± 2.5). CONCLUSIONS Patients with sagittal profile type 1, a small pelvic incidence and reduced compensation mechanisms show a distinct lordosis in the lower lumbar spine and a long thoracolumbar kyphosis. This results in a high axial load and a high load on dorsal structures of the lower lumbar spine with a high load on dorsal structures. A dorsal surgical approach to the lumbar spine can increase low back pain. Patients with these anatomical preconditions, who received a microsurgical decompression present with a significantly worse clinical outcome. Therefore, the decision for microsurgical decompression should be evaluated carefully. Potentially a surgical fusion should be considered. Other possibilities for back pain should be taken into account as well and should be carefully evaluated and treated