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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On the Structured Eigenvalue Problem: Methods, Analysis, and Applications

James P. Vogel (5930360) 17 January 2019 (has links)
<div>This PhD thesis is an important development in the theories, methods, and applications of eigenvalue algorithms for structured matrices. Though eigenvalue problems have been well-studied, the class of matrices that admit very fast (near-linear time) algorithms was quite small until very recently. We developed and implemented a generalization of the famous symmetric tridiagonal divide-and-conquer algorithm to a much larger class of rank structured matrices (symmetric hierarchically semisperable, or HSS) that appear frequently in applications. Altogether, this thesis makes valuable contributions to three different major areas of scientific computing: algorithmic development, numerical analysis, and applications. In addition to the previously stated divide-and-conquer algorithm, we generalize to larger classes of eigenvalue problems and provide several key new low-rank update algorithms. A major contribution the analysis of the structured eigenvalue problem. In addition to standard perturbation analysis, we elucidate some subtle and previously under-examined issues in structured matrix eigenvalue problems such as subspace contributions and secular equation conditioning. Finally, several applications are studied.</div>
2

The study of regional civic aviation market in china

Chen, Fu-chuan 22 June 2007 (has links)
The China¡¦s aviation market has the hugest potential guest group in the world and the special geographical environment disadvantage developing surface transportation, in addition, the economic reform in recent years effect regional civic aviation market positive significantly. In fact, the China regional civic aviation really had some unprecedented progress, and the regional civic aviation environment also had certain improvement, however, the further development for China regional civic aviation was facing another challenge. The research discovered that, the China regional civic aviation got different character. For example, the China¡¦s northwest area regional civic aviation start more early; The southwest province regional civic aviation develop more quickly; The southeast area regional civic aviation passenger has the high payment ability. In sum, the China regional civic aviation market is ubiquitous, how to choose correct market policy and proper regional civic airplane and the network would lead regional civic aviation to obtain the political and economic benefit
3

Efekt intervenčního programu Flowin na hluboký stabilizaniční systém / Effect of Flowin intervention programme on core

Teunerová, Andrea January 2013 (has links)
Title: The Effect of Flowin Intervention Programme on Core Objectives: The aim of this work was to verify the validity of field testing HSS focusing on M. transversus abdominis and evaluate short-term intervention program Flowin to strengthen the CORE group floorball players. Methods: The research group (n = 13) consisting of junior elite floorball players were randomly divided into experimental (N = 7) and control (N = 6) group. The experimental group underwent a 10-week program Flowin aimed at strengthening CORE. The control group continued normal training. The level of engagement CORE was assessed by modified Bunkie test. This is a test in three positions with the aim to maintain the line shoulder-hip-ankle for 30 s. Objectivization was based on video and evaluation path node. To verify the validity testing CORE was selected from a physiotherapist. The four parameters determining the state of the deep stabilizing muscles evaluated on a scale of 1 to 5. It was chosen testing before and after the intervention program. Results: Demonstrated no relationship trajectory node with the evaluation of physiotherapists (R = 0.105). Was no evidence of effectiveness of the intervention program Flowin (average total trajectory in the second measurement was performed in the experimental group: 0.16 ± 0.14 m,...
4

Aplikace PVD povlaků pro frézování / Application of PVD coatings for milling

Matuška, Martin January 2010 (has links)
This dissertation treats of the influence of PVD coats to a change of tool lifetime. The theoretical part of the dissertation describes the adjustment of tools before the process of coating. Following part describes the specific properties of deposited layers of the coating and its measuring. There is also the enumeration and specification of selected ways of depositing PVD coats and brief description of its advantages and disadvantages. Second part of the dissertation is focused on an experiment with measuring of the tool force loading and its change depending to the tool wear. There are compared four short four-edged milling cutters with a coat and as well without it. Those tools were made of high speed steel by the conventional way and also by the powder metallurgy. Milling operation was done by down and up milling technique. The evaluation of the experimental results for powder metallurgy tools confirmed that these tools are advantageous compared to the standard high speed steel tools.
5

Desempeño sísmico de conexiones tipo EP-HSS considerando carga axial y flexión biaxial

Lichtemberg Jurfest, Roberto Alejandro January 2019 (has links)
Tesis para optar al grado de Magíster en Ciencias de la Ingeniería, Mención Ingeniería Estructural, Sísmica y Geotécnica / Memoria para optar al título de Ingeniero Civil / El acero estructural es un material que es ampliamente utilizado en los países de mayor desarrollo para la materialización de estructuras industriales y no industriales por su alta ductilidad y resiliencia al ser diseñadas con metodologías confiables que han tenido buen desempeño luego de eventos sísmicos. Dentro de estas estructuras resaltan los marcos especiales a momento con columnas tubulares (HSS) y vigas de sección I, que son capaces de concentrar la mayor parte de la deformación inelástica en las vigas al ser sujetas a demandas sísmicas considerables. Con el fin de aumentar la resiliencia de estas estructuras, así como la facilidad, rapidez y calidad constructiva es que se propone una conexión viga-columna mediante planchas tipo end-plate (EP) apernada denominada EP-HSS, la cual fue estudiada experimental y numéricamente para caracterizar su comportamiento bajo cargas cíclicas, cumpliéndose los criterios establecidos en la norma americana (AISC 341-10), encontrándose que el mecanismo de falla que prevalece es aquel asociado a una mayor plastificación en las vigas, lo cual corresponde a una falla de tipo dúctil. En el presente estudio se busca ampliar el alcance de investigaciones previas al incluir el efecto de la carga axial y flexión biaxial sobre la columna a través de una simulación numérica mediante el método de elementos finitos (MEF) que incluye no linealidades del material utilizado, geométricas y de contacto entre elementos, así como grandes deformaciones en el sistema. La carga axial se incluye en tres niveles de carga relativos a la carga axial de fluencia de la columna (Py), mientras que la flexión biaxial se considera al variar la cantidad de vigas conectadas a la columna que se deforman a flexión. En añadidura a lo anterior, se realizan simulaciones con modificaciones en el diseño de la conexión para inducir fallas localizadas en esta y estudiar los mecanismos de falla que se generan. Se encuentra que todas las conexiones cumplen con el requerimiento de sostener resistencias a flexión del 80 % del momento plástico nominal de la viga (Mp) para una rotación de 0.04 [rad] como se estipula en la norma AISC 341-16 y presentan un buen desempeño con respecto al criterio de columna fuerte-viga débil, al ser las vigas las principales disipadoras de energía. La respuesta de las conexiones se analizó mediante la conversión a un sistema equivalente en términos de energía de donde se encuentra que el impacto de la carga axial sobre la columna es reducido para los niveles estudiados y que la flexión biaxial tiene un mayor impacto en la histéresis de la conexión mas no induce mecanismos de falla frágiles.
6

Diameter service creation investigation and HSS evaluation

Lindgren, Petter January 2010 (has links)
With a prospect of creating a new generation of cellular networks using IP based communication, service providers, operators and developers have created the IP Multimedia Subsystem (IMS). Which with a more open architecture than older cellular networks will make it more like the internet in terms of service creation. This thesis creates an example service that uses subscriber data in the Home Subscriber Server (HSS) to deliver a service to the network’s users. The service is created to extend the functionality of the IMS test environment at Attentec AB to assist them in their efforts of learning and experimenting with the IMS core network. In this thesis the FoHSS used in the test environment is evaluated in order to measure its performance. This thesis gives examples of the implementation overhead of creating services in the IMS network and shows some of the functionality that is available to IMS services compared to service creation on the internet. Load tests of the FoHSS are made and shows that it uses polling to maintain subscription updates and that it has a negative impact on performance under heavy load. This thesis suggests that it is good for IMS test environments but not commercial use. / Med ambitionen att skapa nästa generations mobilnätverk med IP-baserad kommunikation, har tjänsteleverantörer, operatörer och utvecklare skapat IMS. IMS som med en mer öppen arkitektur än dess föregångare försöker närma sig internet när det gäller skapande av nya tjänster. Det ska vara enklare och ta mindre tid än i ett äldre mobilnät. Detta examensarbete skapar en exempeltjänst som använder användaruppgifter i IMS användardatabas för att leverera en tjänst till nätets användare. Tjänsten har skapats för att utöka funktionerna i den IMS testmiljö som Attentec AB har satt upp för att underlätta för sina anställda att lära sig mer om med IMS-kärnan genom att experimentera med den. I denna avhandling utvärderas även den HSS som finns i testmiljön. Examensarbetet ger exempel på det extraarbete som behöver göras för att skapa tjänster i ett IMS-nätverk och visar på en del av den funktionalitet som finns tillgänglig för tjänster i IMS jämfört med skapande av nya tjänster på Internet. De lasttester som utfördes på användardatabasen visar att den använder pollning för att upptäcka ändringar i användardata och skicka ut uppdateringar till prenumeranter samt att dessa har en negativ inverkan på prestandan under tung belastning. Denna avhandling visar att den passar bra i IMS testmiljöer men för inte kommersiellt bruk.
7

Performance Evaluation and Elastic Scaling of an IP Multimedia Subsystem Implemented in a Cloud

Umair, Muhammad January 2013 (has links)
Network (NGN) technology which enables telecommunication operators to provide multimedia services over fixed and mobile networks. All of the IMS infrastructure protocols work over IP which makes IMS easy to deploy on a cloud platform. The purpose of this thesis is to analysis a novel technique of “cloudifying” the OpenIMS core infrastructure. The primary goal of running OpenIMS in the cloud is to enable a highly available and horizontally scalable Home Subscriber Server (HSS). The resulting database should offer high availability, and high scalability. The prototype developed in this thesis project demonstrates a virtualized OpenIMS core with an integrated horizontal scalable HSS. Functional and performance measurements of the system under test (i.e. the virtualized OpenIMS core with horizontally scalable HSS) were conducted. The results of this testing include an analysis of benchmarking scenarios, the CPU utilization, and the available memory of the virtual machines. Based on these results we conclude that it is both feasible and desirable to deploy the OpenIMS core in a cloud. / IP Multimedia Subsystem (IMS) ramverk är ett Next Generation Network (NGN) teknik som möjliggör teleoperatörer att erbjuda multimediatjänster via fasta och mobila nät. Alla IMS infrastruktur protokollen fungera över IP som gör IMS lätt att distribuera på ett moln plattform. Syftet med denna uppsats är att analysera en ny teknik för “cloudifying” den OpenIMS kärninfrastrukturen.  Det primära målet med att köra OpenIMS i molnet är att möjliggöra en hög tillgänglighet och horisontellt skalbara Server Home Subscriber (HSS). Den resulterande databasen bör erbjuda hög tillgänglighet och hög skalbarhet. Prototypen utvecklas i detta examensarbete visar en virtualiserad OpenIMS kärna med en integrerad horisontell skalbar HSS. Funktionella och prestanda mätningar av systemet under test (dvs. virtualiserade OpenIMS kärnan med horisontellt skalbara HSS) genomfördes. Resultaten av detta test inkluderar en analys av benchmarking scenarier, CPU-användning, och tillgängligt minne för de virtuella maskinerna. Baserat på dessa resultat drar vi slutsatsen att det är både möjligt och önskvärt att distribuera OpenIMS kärnan i ett moln.
8

Reexamination of Shear Lag in HSS Tension Members; Side Gusset Plate Connections

Bhat, Akashdeep January 2018 (has links)
No description available.
9

Harmonic state space modelling of voltage source converters

Ormrod, James Ernest January 2013 (has links)
The thesis describes the development of a model of the three-phase Voltage Source Converter (VSC) in the Harmonic State Space (HSS) domain, a Linear Time Periodic (LTP) extension to the Linear Time Invariant (LTI) state space. The HSS model of the VSC directly captures harmonic coupling effects using harmonic domain modelling concepts, generalised to dynami- cally varying signals. Constructing the model using a reduced-order three-phase harmonic signal representation achieves conceptual simplification, reduced computational load, and direct inte- gration with a synchronous frame vector control scheme. The numerical switching model of the VSC is linearised to gain a small-signal controlled model, which is validated against time-domain PSCAD/EMTDC simulations. The controlled model is evaluated as a STATCOM-type system, exercising closed-loop control over the reactive power flow and dc-side capacitor voltage using a simple linear control scheme. The resulting state- space model is analysed using conventional LTI techniques, giving pole-zero and root-locus analyses which predict the dynamic behaviour of the converter system. Through the ability to independently vary the highest simulated harmonic order, the dependence on the closed-loop response to dynamic harmonic coupling is demonstrated, distinguishing the HSS model from fundamental-only Dynamic Phasor models by its ability to accurately model these dynamics.
10

Burnout in Pre-licensed Counselors Compared to Licensed Counselors

Mueller, Alexis Y 18 May 2018 (has links)
The first purpose of the study was to assess burnout in pre-licensed counselors who are working towards licensure compared to burnout in counselors who are already licensed. The second purpose of the study was to assess what factors contribute to burnout in pre-licensed counselors. Counselors working towards licensure were an under-studied population at risk for burnout. Further, burnout of counselors working to gain their licensure had not been studied previously. A total of 2,400 pre-licensed and licensed counselors in Florida and Louisiana were emailed the quantitative survey. The instrument included a researcher designed demographic survey and the Maslach’s Burnout Inventory for Human Services (MBI-HSS). Using descriptive statistic ANOVA, inferential statistic Levene’s test and non-parametric tests including Spearman’s rho, and Kruskall-Wallis were calculated to measure the degree of burnout and to compare burnout scores of licensed counselors and pre-licensed counselors working toward licensure. Results of this study indicate that pre-licensed counselors experienced high levels of burnout in emotional exhaustion, moderate levels of burnout in depersonalization, and inversely high levels of personal accomplishment. Licensed counselors exhibited moderate levels of emotional exhaustion and depersonalization and inversely high levels of personal accomplishment. In addition, the following demographics were found statistically significant in burnout of pre-licensed counselors: age, weekly supervision, work setting, and client population.

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