Phase And Amplitude Modulated Ofdm For Dispersion Managed Wdm Systems

Amplitude and phase modulated optical OFDM (Orthogonal Frequency Division Multiplexing) are analyzed in a 50GBit/s single channel and 40GBit/s 5 channel 512 subcarrier non-ideal dispersion-compensated fiber optic communication systems. PM-OFDM is investigated as an alternative to AM-OFDM to alleviate the problem associated with amplitude-modulated signals in a nonlinear medium. The inherent dispersion compensation capability in OFDM (using a cyclic prefix) allows transmission over a link whose dispersion map is not exactly known. OFDM also mitigates the effects of dispersion slope in wavelength-division multiplexed (WDM) systems. Moreover, the overall dispersion throughout the transmission link may vary due to environmental effects and aging. OFDM is inherently tolerant to over- or under-compensation and dispersion slope mismatch. OFDM transmission over dispersive, non-dispersion managed fiber links using OFDM requires an overhead in excess of the maximum accumulated dispersion. Existing WDM systems usually employ periodic dispersion management. OFDM in these systems requires a smaller overhead. It is, however, more susceptible to nonlinearity due to the coherent beating of subcarriers after each dispersion-compensated span. The large variation in intensity associated with amplitude-modulated OFDM makes this modulation format more susceptible to nonlinear effects in fiber compared to phase-modulated signals. This holds true unless dispersion and EDFA noise lead to amplitude variations strong enough for PM-OFDM to be degraded by nonlinear effects as well. In conclusion OFDM is beneficial for non-ideal dispersion managed systems. PM-OFDM can further improve the performance

Millimeter-Precision Laser Rangefinder Using a Low-Cost Photon Counter

In this book we successfully demonstrate a millimeter-precision laser rangefinder using a low-cost photon counter. An application-specific integrated circuit (ASIC) comprises timing circuitry and single-photon avalanche diodes (SPADs) as the photodetectors. For the timing circuitry, a novel binning architecture for sampling the received signal is proposed which mitigates non-idealities that are inherent to a system with SPADs and timing circuitry in one chip

The DeepThought Core Architecture Framework

The research performed in the DeepThought project aims at demonstrating the potential of deep linguistic processing if combined with shallow methods for robustness. Classical information retrieval is extended by high precision concept indexing and relation detection. On the basis of this approach, the feasibility of three ambitious applications will be demonstrated, namely: precise information extraction for business intelligence; email response management for customer relationship management; creativity support for document production and collective brainstorming. Common to these applications, and the basis for their development is the XML-based, RMRS-enabled core architecture framework that will be described in detail in this paper. The framework is not limited to the applications envisaged in the DeepThought project, but can also be employed e.g. to generate and make use of XML standoff annotation of documents and linguistic corpora, and in general for a wide range of NLP-based applications and research purposes

Kurswertreaktionen auf die Ankündigung von Going Private : Transaktionen am deutschen Kapitalmarkt

Der Beitrag ist wie folgt aufgebaut. In Abschnitt 2 wird zunächst der Begriff des Going Private definiert und anhand kurzer Ausführungen zu den handelnden Akteuren Einblicke in die Funktionsweise des deutschen Going Private-Marktes vermittelt. In Abschnitt 3 wird die zu überprüfende Hypothese abgeleitet, dass eine Going Private-Ankündigung mit einer positiven Kurswertreaktion verbunden ist. Abschnitt 4 legt den Prozess der Stichprobenauswahl offen und liefert einige deskriptive Informationen zur Marktkapitalisierung deutscher Going Private- Unternehmen. Anschließend wird in Abschnitt 5 die verwendete Untersuchungsmethode der Ereignisstudie beschrieben. Im nachfolgenden Abschnitt 6 werden die Untersuchungsergebnisse präsentiert. Dabei wird nicht nur die Hypothese überprüft, dass Going Private- Ankündigungen eine positive Kurswertreaktion hervorrufen. Vielmehr werden auch Aussagen über die Geschwindigkeit der Kursanpassung getroffen. In Abschnitt 7 wird ferner untersucht, inwiefern sich die kumulierten abnormalen Renditen bezüglich spezifischer Charakteristika der Going Private-Transaktionen unterscheiden. Der abschließende Abschnitt 8 fasst die Ergebnisse der Untersuchung zusammen. --

Hybrid robust deep and shallow semantic processing for creativity support in document production

The research performed in the DeepThought project (http://www.project-deepthought.net) aims at demonstrating the potential of deep linguistic processing if added to existing shallow methods that ensure robustness. Classical information retrieval is extended by high precision concept indexing and relation detection. We use this approach to demonstrate the feasibility of three ambitious applications, one of which is a tool for creativity support in document production and collective brainstorming. This application is described in detail in this paper. Common to all three applications, and the basis for their development is a platform for integrated linguistic processing. This platform is based on a generic software architecture that combines multiple NLP components and on robust minimal recursive semantics (RMRS) as a uniform representation language

Darstellung und stochastische Auflösung von Ambiguität in constraint-basiertem Parsing

Diese Arbeit untersucht zwei komplementäre Ansätze zum Umgang mit Mehrdeutigkeiten bei der automatischen Verarbeitung natürlicher Sprache. Zunächst werden Methoden vorgestellt, die es erlauben, viele konkurrierende Interpretationen in einer gemeinsamen Datenstruktur kompakt zu repräsentieren. Dann werden Ansätze vorgeschlagen, die verschiedenen Interpretationen mit Hilfe von stochastischen Modellen zu bewerten. Für das dabei auftretende Problem, Wahrscheinlichkeiten von seltenen Ereignissen zu schätzen, die in den Trainingsdaten nicht auftraten, werden neuartige Methoden vorgeschlagen.This thesis investigates two complementary approches to cope with ambiguities in natural language processing. It first presents methods that allow to store many competing interpretations compactly in one shared datastructure. It then suggests approaches to score the different interpretations using stochastic models. This leads to the problem of estimation of probabilities of rare events that have not been observed in the training data, for which novel methods are proposed

Holographische Abbildung von Nanostrukturen durch Projektions-Elektronenmikroskopie

Konstruiert wurde ein neuartiges Elektronenprojektionsmikroskop zur Aufnahme von Nanostrukturen und strangartigen Molekülen. Es wurde ein Theoretisches Modell aujfgestellt zur Analyse und Interpretation der Aufgenommenen Streubilder. Ein numerischer Algorithmus wurde entwickelt, der eine Rekonstruktion der Daten innerhalb experimentell kurzer Zeit ermöglicht. Die gewonnenen experimentellen Daten zeigen eine reproduzierbare Auflösung im Bereich weniger Nanometer

Millimeter-Precision Laser Rangefinder Using a Low-Cost Photon Counter

In this book we successfully demonstrate a millimeter-precision laser rangefinder using a low-cost photon counter. An application-specific integrated circuit (ASIC) comprises timing circuitry and single-photon avalanche diodes (SPADs) as the photodetectors. For the timing circuitry, a novel binning architecture for sampling the received signal is proposed which mitigates non-idealities that are inherent to a system with SPADs and timing circuitry in one chip

Apropriação indébita e ilícito penal tributário

Orientador: Prof. Dr. René Ariel DottiDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Jurídicas, Programa de Pós-Graduação em DireitoInclui referências: p. 146-153Não inclui resum