A Tutorial for Using the CGT Script Library to Generate and Assemble Overset Meshes

The purpose of this document is to introduce a new user to the procedures for overset CFD analysis by building scripts based on the CGT Script Library. Parameterized inputs are built into the steps of the process which include creation and manipulation of geometry, and surface and volume meshing. In preparation for performing computations in the flow solver, further steps are constructed for specification of inputs for domain connectivity, flow solver boundary conditions, and components for computation of aerodynamic forces/moments. The JCLV rocket will be used as an example geometry for this demonstration

A psychophysical investigation of global illumination algorithms used in augmented reality

Global illumination rendering algorithms are capable of producing images that are visually realistic. However, this typically comes at a large computational expense. The overarching goal of this research was to compare different rendering solutions in order to understand why some yield better results when applied to rendering synthetic objects into real photographs. As rendered images are ultimately viewed by human observers, it was logical to use psychophysics to investigate these differences. A psychophysical experiment was conducted judging the composite images for accuracy to the original photograph. In addition, iCAM, an image color appearance model, was used to calculate image differences for the same set of images. In general it was determined that any full global illumination is better than direct illumination solutions only. Also, it was discovered that the full rendering with all of its artifacts is not necessarily an indicator of judged accuracy for the final composite image. Finally, initial results show promise in using iCAM to predict a relationship similar to the psychophysics, which could eventually be used in-the-rendering-loop to achieve photo-realism

Improving effectiveness of regression testing of telecommunications system software

Regressiotestaus on osoittautunut kalliiksi tavaksi varmistaa uusien ohjelmistoversioiden toimivuus. Kustannukset johtuvat ajasta ja resursseista, jotka kuluvat testien suorittamiseen. Kahta erilaista lähestymistapaa on tyypillisesti sovellettu regressiotestauksen kustannustehokkuuden parantamiseen: testien valintatekniikka tai testiautomaatio. Tämän diplomityön tavoitteena on tutkia, kumpaa kahdesta yllämainitusta lähestymistavasta kannattaisi hyödyntää, kun regressiotestauksen kustannustehokkuutta halutaan parantaa kohdeyrityksessä. Kohdeyritys on suuri suomalainen tietoliikennejärjestelmien kehittäjä, jonka päätuote tällä hetkellä on IP/MPLS pohjainen järjestelmä. Tämä järjestelmä sisältää useita eri kapasiteetein varustettuja IP/MPLS reitittimiä, joita käytetään pääsyverkoissa. Järjestelmän avulla voidaan tarjota käyttäjille palvelunlaatuun pohjautuvia palveluja. Diplomityön tavoitetta lähestytään tutkimalla tämän hetkistä regressiotestausta kohdeyrityksessä. Tämän jälkeen hyödynnetään sekä testien valintatekniikkaa että testiautomaatiota rajoitetussa mittakaavassa. Näiden menetelmien toimivuutta arvioidaan empiirisesti kustannustehokkuutta vasten.Regression testing is an expensive process used to validate new software versions. The cost of regression testing accumulates from the time and resources spent on running the tests. To improve the cost-effectiveness of regression testing, typically two fundamentally different approaches have been utilized: test selection techniques or test automation. The goal of this thesis is to explore whether test selection techniques or test automation should be utilized in order to improve the cost-effectiveness of regression testing at the target company. The target company is a Finnish telecommunications systems developer whose main deliverable is the product family consisting of several IP/MPLS routers. These routers are deployed in access-networks in order to provide QoS related services, such as, Intranet, Extranet, VPNs and corporate voice services. To achieve the goal, the present regression testing practices are explored first. After that, a test selection technique and test automation are utilized in a limited scope. Their impact to cost-effectiveness will be evaluated empirically and the recommended method is presented

Gallium nitride simulations using Sentaurus software

Questa attività di tesi, svolta in NXP Semiconductors R&D – Belgio in collaborazione con il DEI, ha avuto come oggetto l’ottenimento di modelli di simulazione per strutture HEMT in GaN/AlGaN, usando il software Sentaurus by Synopsys versione 2010.03. Prima di tutto sono state svolte simulazioni sia DC (IdVg, IdVd) che AC (Cgg) in modo tale da calibrare i nostri modelli basandoci su delle misure effettuate nei laboratori di NXP. In questa fase sono state aggiunte trappole nel dispositivo e variando la concentrazione e l’energia di attivazione di queste ultime è stato ottenuto un ottimo matching fra caratteristiche sperimentali e simulazioni. Partendo da questi modelli si è cercato poi di implementare un nuovo modello di mobiità calibrato per il GaN, usando l’interfaccia C++ del simulatore. Simulazioni di gate leakage sono state effettuate per cercare di dare una spiegazione a questo fenomeno, il quale impatta negativamente sulle prestazioni di questi dispositivi. Infine si è cercato di studiare la distribuzione del campo elettrico nel canale, variando la lunghezza del Field Plat

Charging effects in niobium nanostructures

Three types of metallic nanostructures comprising niobium were investigated experimentally; in all three types, electric transport at very low temperatures was governed by Coulomb blockade effects. 1. Thin film strips of niobium could be tuned into resistor strips by an electrochemical anodisation process, using microfabricated masks and in situ resistance monitoring. These resistors showed a transition from superconducting to insulating behaviour with increasing sheet resistance, occurring at a value approximately equal to the quantum resistance for Cooper pairs, h/(4e^2). 2. Combining the anodisation technique with lateral size minimisation by shadow evaporation, devices in a single electron transistor-like configuration with two weak links and a small island between these were made. Direct evidence for the Coulomb blockade in the anodisation thinned niobium films was found when the transport characteristics could be modulated periodically by sweeping the voltage applied to a gate electrode placed on top of the structure. 3. Conventional single electron transistors with Al base electrodes, AlO_x barriers formed in situ by oxidation, and Nb top electrodes were made by angular evaporation. The output current noise of such a transistor was measured as a function of bias voltage, gate voltage, and temperature. The low frequency noise was found to be dominated by charge input noise. The dependence of the noise on the bias voltage is consistent with self-heating of the transistor activating the noise sources.Comment: PhD thesis, 177 pages, 42 figures (images downsampled

Kinetics of Oxygen Transport in Monomeric Sarcosine Oxidase

Flavin-containing oxidases are a class of proteins which use oxygen to regenerate the oxidized state of the isoalloxazine ring in flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN) after it has been reduced by substrate oxidation. Though well characterized experimentally, many questions linger regarding how small molecules access the active site as well as where oxygen activation occurs in flavin-containing oxidases. A prototypical member of this family is monomeric sarcosine oxidase (MSOX), and it is perhaps the most well studied. Despite knowing which features are essential for catalysis as well as the location of the substrate binding site, it is unclear how oxygen accesses the site since the only clear entryway can be partially blocked by the larger substrate sarcosine. As such, two competing mechanisms have gained attention centering around the order by which ligands enter the binding site. In this thesis, we detail the use of all atom molecular dynamics (MD) studies to identify how oxygen accesses the MSOX active site, as well as characterize the resulting kinetic network. We use the single sweep method to identify four potential routes for oxygen to travel from the surface of MSOX to the active site. Then, using Markovian milestoning with Voronoi tessellations (MMVT), we refine the pathways identified in single sweep and develop a Markov state model describing the kinetics of oxygen entry and exit. We calculate entry and exit mean first passage times (MFPT) for oxygen from this model, which are used to compute second order rate constants for entry and first order rate constants for exit. Our calculated rate constants and mechanisms show that the presence of a substrate-mimicking inhibitor markedly influences the kinetics of oxygen entry and exit. The bound competitive inhibitor changes the protein structure sufficiently to shut down almost all major oxygen channels save one, which it opens, speeding entry but greatly slowing down oxygen exit, relative to the substrate-free enzyme. This means that our kinetic analysis predicts oxygen exhibits a longer residence time within MSOX when a substrate-like ligand is present. This supports the so-called "modified ping-pong" mechanism, in agreement with previous experimental results, thus lending validity to our approach. Furthermore, our computed second-order entry rate constants are larger by about an order of magnitude than are experimentally determined oxygen consumption rate constants. Since oxygen consumption combines the processes of entry and electron transfer, we conclude that of these two, entry is not rate-limiting in the overall catalytic cycle, regardless of whether or not a substrate-like ligand is bound. Finally, because this work represents the first test of the MMVT approach for comparing kinetics of ligand entry for an enzyme in two distinct states, we not surprisingly uncovered inefficiencies in the approach. We tested one idea for gaining efficiency based on the "finite-temperature" string method, in which transport channels can be determined and kinetically characterized on-the-fly, rather than sequentially. Our results indicate that more research in that area is needed.Ph.D., Chemical Engineering -- Drexel University, 201

Raising the abstraction level of hardware software co-designs

As lithographic processes’ size to manufacture transistors shrink, the number of available transistors on integrated circuits (IC) increases. Newly manufactured ICs require innovations to leverage improved performances or area occupation, and feature more and more components on the same chip, which work together and/or independently to provide an advanced set of functions. The complexity of hardware design flows consequently increased: from circuit description to functional verification and in-system interface, every stage is now more and more driven by a cross-product function between a set of reusable functional units and constraints to target a specific technology (ASIC, FPGAs etc…) and configuration. This diversity in the possible outputs for a set of components calls for the development of new methodologies to raise the abstraction level in the design flows. A better abstraction allows optimizing and automating more processes, from component specification to final implementation and interfacing. New Abstraction levels have always emerged through industry standards like Verilog and VHDL for digital circuit description, SystemVerilog/UVM/e for functional verification, or by vendor specific toolchains. However, standards and software toolchains usually lack flexibility as they operate for a bounded range of functionalities. This thesis presents some novel applications covering various stages of the design flow, ranging from digital design input (register file generator) and ASIC circuit implementation (Hierarchical Floorplaning), up to in-system IC integration (Part design language). They are backed by a generic software design methodology based on functional programming used to develop domain specific languages embedded in the TCL interpreter. To complete the design flow path from circuit implementation to software integration, a hardware-software interfacing point linked with the Register File Generator design tool will be presented. It is based on a generic and innovative XML-Data binding technology which was developed during this work. The iterative loop between application definition and flexible software components reuse presented along this work also provides a general guideline to develop future design flow components, and guarantee their integration in any target environment

PERFORMANCE CHARACTERISATION OF IP NETWORKS

The initial rapid expansion of the Internet, in terms of complexity and number of hosts, was followed by an increased interest in its overall parameters and the quality the network offers. This growth has led, in the first instance, to extensive research in the area of network monitoring, in order to better understand the characteristics of the current Internet. In parallel, studies were made in the area of protocol performance modelling, aiming to estimate the performance of various Internet applications. A key goal of this research project was the analysis of current Internet traffic performance from a dual perspective: monitoring and prediction. In order to achieve this, the study has three main phases. It starts by describing the relationship between data transfer performance and network conditions, a relationship that proves to be critical when studying application performance. The next phase proposes a novel architecture of inferring network conditions and transfer parameters using captured traffic analysis. The final phase describes a novel alternative to current TCP (Transmission Control Protocol) models, which provides the relationship between network, data transfer, and client characteristics on one side, and the resulting TCP performance on the other, while accounting for the features of current Internet transfers. The proposed inference analysis method for network and transfer parameters uses online nonintrusive monitoring of captured traffic from a single point. This technique overcomes limitations of prior approaches that are typically geared towards intrusive and/or dual-point offline analysis. The method includes several novel aspects, such as TCP timestamp analysis, which allows bottleneck bandwidth inference and more accurate receiver-based parameter measurement, which are not possible using traditional acknowledgment-based inference. The the results of the traffic analysis determine the location of the eventual degradations in network conditions relative to the position of the monitoring point. The proposed monitoring framework infers the performance parameters of network paths conditions transited by the analysed traffic, subject to the position of the monitoring point, and it can be used as a starting point in pro-active network management. The TCP performance prediction model is based on the observation that current, potentially unknown, TCP implementations, as well as connection characteristics, are too complex for a mathematical model. The model proposed in this thesis uses an artificial intelligence-based analysis method to establish the relationship between the parameters that influence the evolution of the TCP transfers and the resulting performance of those transfers. Based on preliminary tests of classification and function approximation algorithms, a neural network analysis approach was preferred due to its prediction accuracy. Both the monitoring method and the prediction model are validated using a combination of traffic traces, ranging from synthetic transfers / environments, produced using a network simulator/emulator, to traces produced using a script-based, controlled client and uncontrolled traces, both using real Internet traffic. The validation tests indicate that the proposed approaches provide better accuracy in terms of inferring network conditions and predicting transfer performance in comparison with previous methods. The non-intrusive analysis of the real network traces provides comprehensive information on the current Internet characteristics, indicating low-loss, low-delay, and high-bottleneck bandwidth conditions for the majority of the studied paths. Overall, this study provides a method for inferring the characteristics of Internet paths based on traffic analysis, an efficient methodology for predicting TCP transfer performance, and a firm basis for future research in the areas of traffic analysis and performance modelling

Oriental traits in Liam de Noraidh's collection of Irish folk melodies : a particular instance of a general cultural condition.

Thesis (Ph.D.)-University of Natal, Durban, 1982.No abstract available