In digital communication systems symbol timing recovery is of fundamental importance. The accuracy in estimation of symbol timing has a direct effect on received data error rates. The primary objective of this thesis is to implement a practical Digital Phase Locked Loop capable of accurate synchronisation of symbols suffering channel corruption typical of modern mobile communications. This thesis describes an all-software implementation of a Digital Phase Locked in a real-time system. A timing error detection (TED) algorithms optimally implemented into a Digital Signal Processor. A real-time transmitter and receiver system is implemented in order to measure performance when the received signal is corrupted by both Additive White Gaussian Noise and Flat Fading. The Timing Error Detection algorithm implemented is a discrete time maximum likelihood one known as FFML1, developed at Canterbury University. FFML1 along with other components of the Digital Phase Locked loop are implemented entirely in software, using Motorola 56321 assembly language.

A reforming trend is captured showing that countries are shifting from defined benefit pension systems towards defined contribution systems. The reforms have been justified through predictions that the defined benefit systems will not manage to provide good enough pensions to members in the future. The newer defined contribution pension plans often include individual financial accounts where individuals have the possibility to choose how a part of their pension savings should be invested. Sweden was early to introduce such a system, which at the moment provides more than 800 funds to choose from. The aim of this thesis is to capture the market risk associated with these individual investments and does so by using Monte Carlo simulations for six selected pension funds. The method produces forecasts of replacement ratios, pension as percentage of pre-retirement income, for two hypothetical individuals: one who starts to work right after elementary school and one individual who starts a five year education and after graduation starts to work. The results show a slightly lower replacement ratio for the educated individual, which also is associated with a higher probability of ending up with a low replacement ratio. The market risk also varies between the funds, which implies that the funds should be chosen with great care. The study ends with arguments for an increasing paternalism with a carefully considered fund offering, providing fewer funds to choose from than today.

Intelligent tutoring systems and computer-supported collaborative environments have been designed to enhance human learning in various domains. While a number of solid techniques have been developed in the Artificial Intelligence in Education (AIED) field to foster human learning in fundamental science domains, there is still a lack of evidence about how to support learning in so-called ill-defined domains that are characterized by the absence of formal domain theories, uncertainty about best solution strategies and teaching practices, and learners' answers represented through text and argumentation. This dissertation investigates how to support students' learning in the ill-defined domain of professional ethics through a computer-based learning system. More specifically, it examines how to support students in the analysis of case studies, which is a common pedagogical practice in the ethics domain. This dissertation describes our design considerations and a resulting system called Umka. In Umka learners analyze case studies individually and collaboratively that pose some ethical or professional dilemmas. Umka provides various types of support to learners in the analysis task. In the individual analysis it provides various kinds of feedback to arguments of learners based on predefined system knowledge. In the collaborative analysis Umka fosters learners' interactions and self-reflection through system suggestions and a specifically designed visualization. The system suggestions offer learners the chance to consider certain helpful arguments of their peers, or to interact with certain helpful peers. The visualization highlights similarities and differences between the learners' positions, and illustrates the learners' level of acceptance of each other's positions. This dissertation reports on a series of experiments in which we evaluated the effectiveness of Umka's support features, and suggests several research contributions. Through this work, it is shown that despite the ill-definedness of the ethics domain, and the consequent complications of text processing and domain modelling, it is possible to build effective tutoring systems for supporting students' learning in this domain. Moreover, the techniques developed through this research for the ethics domain can be readily expanded to other ill-defined domains, where argument, qualitative analysis, metacognition and interaction over case studies are key pedagogical practices.

Datacenters are a significant capital expense for many enterprises. Yet, they are difficult to manage and are hard to design and maintain. The initial design of a datacenter network tends to follow vendor guidelines, but subsequent upgrades and expansions to it are mostly ad hoc, with equipment being upgraded piecemeal after its amortization period runs out and equipment acquisition is tied to budget cycles rather than changes in workload. These networks are also brittle and inflexible. They tend to be manually managed, and cannot perform dynamic traffic engineering. The high-level goal of this dissertation is to reduce the total cost of owning a datacenter by improving its network. To achieve this, we make the following contributions. First, we develop an automated, theoretically well-founded approach to planning cost-effective datacenter upgrades and expansions. Second, we propose a scalable traffic management framework for datacenter networks. Together, we show that these contributions can significantly reduce the cost of operating a datacenter network. To design cost-effective network topologies, especially as the network expands over time, updated equipment must coexist with legacy equipment, which makes the network heterogeneous. However, heterogeneous high-performance network designs are not well understood. Our first step, therefore, is to develop the theory of heterogeneous Clos topologies. Using our theory, we propose an optimization framework, called LEGUP, which designs a heterogeneous Clos network to implement in a new or legacy datacenter. Although effective, LEGUP imposes a certain amount of structure on the network. To deal with situations when this is infeasible, our second contribution is a framework, called REWIRE, which using optimization to design unstructured DCN topologies. Our results indicate that these unstructured topologies have up to 100-500\% more bisection bandwidth than a fat-tree for the same dollar cost. Our third contribution is two frameworks for datacenter network traffic engineering. Because of the multiplicity of end-to-end paths in DCN fabrics, such as Clos networks and the topologies designed by REWIRE, careful traffic engineering is needed to maximize throughput. This requires timely detection of elephant flows---flows that carry large amount of data---and management of those flows. Previously proposed approaches incur high monitoring overheads, consume significant switch resources, or have long detection times. We make two proposals for elephant flow detection. First, in the Mahout framework, we suggest that such flows be detected by observing the end hosts' socket buffers, which provide efficient visibility of flow behavior. Second, in the DevoFlow framework, we add efficient stats-collection mechanisms to network switches. Using simulations and experiments, we show that these frameworks reduce traffic engineering overheads by at least an order of magnitude while still providing near-optimal performance.

The evolution of wireless technology has necessitated the support of multiple communication standards by mobile devices. At present, multiple chipsets/radios operating at predefined sets of modulation schemes, frequency bands, bandwidths and output power levels are used to achieve this objective. This leads to higher component counts, increased cost and limits the capacity to cope with future communication standards. In order to tackle different wireless standards using a single chipset, digital circuits have been increasingly deployed in radios and demonstrated re-configurability in different modulation schemes (multimode) and frequency bands (multiband). Despite efforts and progress made in digitizing the entire radio, the power amplifier (PA) is still designed using an conventional approach and has become the bottleneck in digital transmitters, in terms of low average power efficiency, poor compatibility with modern CMOS technology and limited re-configurability. This research addresses these issues from two aspects. The first half of the thesis investigates signal encoding issues between the modulator and PA. We propose, analyze and evaluate a new hybrid amplitude/time signal encoding scheme that significantly improves the coding efficiency and dynamic range of a digitally modulated power amplifier (DMPA) without significantly increasing design complexity. The proposed hybrid amplitude/time encoding scheme combines both the amplitude domain and the time domain to optimally encode information. Experimental results show that hybrid amplitude/time encoding results in a 35% increase in the average coding efficiency with respect to conventional time encoding, and is only 6.7% lower than peak efficiency when applied to a Wireless Local Area Network (WLAN) signal with a peak to average power ratio equal to 9.9 dB. A new DMPA architecture, based on the proposed hybrid encoding, is also proposed. The second half of this thesis presents the design, analysis and implementation of a CMOS PA that is amenable to the proposed hybrid encoding scheme. A multi-way current mode class-D PA architecture has been proposed and realized in 130 nm CMOS technology. The designed PA has satisfied the objectives of wide bandwidth (1.5 GHz - 2.7 GHz at 1 dB output power), and high efficiency (PAE 63%) in addition to demonstrating linear responses using the proposed digital encoding. A complete digital transmitter combining the encoder and the multi-way PA was also investigated. The overall efficiency is 27% modulating 7.3 dB peak to average power ratio QAM signals.

Variable digital filters (VDF) find many application areas in communication, audio, speech and image processing. This thesis analyzes design and implementation of FIR digital filters with variable frequency characteristics and introduces two design methods. The design and implementation of the proposed methods are realized on Matlab software program. Various filter design examples and comparisons are also outlilned. One of the major application areas of VDFs is software defined radio (SDR). The interpolation problem on sample rate converter (SRC) unit of the SDR is solved by using these filters. Realizations of VDFs on SRC are outlined and described. Simulations on Simulink and a specific hardware are examined.

This represents a proof-of-concept study of the appropriateness of vibrational and NMR spectroscopy for predicting the molecular structure of large molecules on the basis of a library of small molecules. Density Functional Theory (DFT) B3LYP/6-311G was used generate all spectra. 20 model compounds comprising two multiple-ringed polynuclear aromatic hydrocarbons (PAHs) connected by varying aliphatic chain-lengths were investigated. A least squares optimization algorithm was developed to determine the contribution of molecular subunits in the model compounds. 1H and 13C NMR spectroscopy failed to identify subunits unambiguously even with a constrained library. By contrast, IR and Raman results independently identified 40% and 65% respectively and jointly more than 80 % of the aromatic groups present; however, the aliphatic chain-length was poorly defined in general. IR and Raman spectroscopy are a suitable basis for spectral decomposition and should play a greater role in the identification of ringed subunits present in ill-defined hydrocarbons / Chemical Engineering

Die vorliegende Arbeit behandelt die Anlage von Pensionsvermögen im Rahmen von Contractual Trust Arrangements. Es wird untersucht, welche Anlagestrategien sich unter Berücksichtigung bilanzieller, verpflichtungs- und vermögensseitiger Rahmenbedingungen zur Anlage von Pensionsvermögen eignen. Anhand eines geeigneten Anlagemodells für Pensionsvermögen und der Durchführung einer stochastischen Simulation wird analysiert, welchen Einfluss unterschiedliche Anlagestrategien auf die Entwicklung des Pensionsvermögens haben. Die Arbeit geht zunächst den Hintergrund der betrieblichen Altersversorgung und Contractual Trust Arrangements in Deutschland ein. Zur Abbildung der Verpflichtungsseite und der Mitarbeiterstruktur des Unternehmens wird unter Einbezug aktuarischer Ansätze ein Mitarbeitermodell entwickelt. Das in der Arbeit entwickelte Portfoliomodell integriert die Verpflichtungs- und Vermögensseite und zeigt, wie das Vermögen zur Deckung leistungsorientierter Zusagen zur betrieblichen Altersversorgung unter Einbezug der Unternehmensperspektive mit Hilfe dynamischer Risikonebenbedingungen geeignet angelegt werden kann.

Die vorliegende Arbeit behandelt die Anlage von Pensionsvermögen im Rahmen von Contractual Trust Arrangements. Es wird untersucht, welche Anlagestrategien sich unter Berücksichtigung bilanzieller, verpflichtungs- und vermögensseitiger Rahmenbedingungen zur Anlage von Pensionsvermögen eignen. Anhand eines geeigneten Anlagemodells für Pensionsvermögen und der Durchführung einer stochastischen Simulation wird analysiert, welchen Einfluss unterschiedliche Anlagestrategien auf die Entwicklung des Pensionsvermögens haben. Die Arbeit geht zunächst auf den Hintergrund der betrieblichen Altersversorgung und Contractual Trust Arrangements in Deutschland ein. Zur Abbildung der Verpflichtungsseite und der Mitarbeiterstruktur des Unternehmens wird unter Einbezug aktuarischer Ansätze ein Mitarbeitermodell entwickelt. Das in der Arbeit entwickelte Portfoliomodell integriert die Verpflichtungs- und Vermögensseite und zeigt, wie das Vermögen zur Deckung leistungsorientierter Zusagen zur betrieblichen Altersversorgung unter Einbezug der Unternehmensperspektive mit Hilfe dynamischer Risikonebenbedingungen geeignet angelegt werden kann.

"Submitted in partial fulfillment of the requirements for the degree of Master of Business Administration from the Naval Postgraduate School, June 2009." / Advisor(s): Henderson, David R. ; Eitelberg, Mark J. "June 2009." "MBA professional report"--Cover. Description based on title screen as viewed on July 14, 2009. Author(s) subject terms: Military Retirement, Retirement Information Sources, Retirement Information Systems, General Military Training, Military Compensation, Defined Benefit Plan, Defined Contribution Plan, Military Pension, Military Retirement Fund, and Military Retirement Communication Modes. Includes bibliographical references (p. 73-74). Also available in print.