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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.
611

How the choice of Operating System can affect databases on a Virtual Machine

Karlsson, Jan, Eriksson, Patrik January 2014 (has links)
As databases grow in size, the need for optimizing databases is becoming a necessity. Choosing the right operating system to support your database becomes paramount to ensure that the database is fully utilized. Furthermore with the virtualization of operating systems becoming more commonplace, we find ourselves with more choices than we ever faced before. This paper demonstrates why the choice of operating system plays an integral part in deciding the right database for your system in a virtual environment. This paper contains an experiment which measured benchmark performance of a Database management system on various virtual operating systems. This experiment shows the effect a virtual operating system has on the database management system that runs upon it. These findings will help to promote future research into this area as well as provide a foundation on which future research can be based upon.
612

Exploring healthy vending contracts as a localized policy approach to improve the nutrition environment in publicly funded recreation facilities

Lane, Cassandra 19 April 2018 (has links)
Objective: Many Canadian publicly funded recreation facilities have an obesogenic environment. Researchers recommend food and beverage policies to change these environments, however further research is needed to distinguish effective policy approaches. A promising, localized policy approach not yet well evidenced is the use of vending machine contracts with health stipulations to improve nutrition environments. The primary objective of this study was to determine whether a sample of Canadian publicly funded recreation facilities with healthy vending contracts had healthier vending machine nutrition profiles than those facilities with conventional contracts. A secondary research objective was to explore the additional influence of policy quality on the health profile of vending machines. Methods: This quantitative study used results from the baseline assessment done of the broader Eat, Play, Live (EPL) initiative. Vending machine audits and questionnaires were completed in participating publicly funded recreation facilities with vending machines (N=46). Vending product profiles were assessed using the Brand Name Food List which categorizes packaged foods according to the BC Guidelines for Vending in Public Buildings. Mann-Whitney U tests were used to determine if there were significant differences in the health profile of vending products between facilities with healthy vending contracts and those without. Results: Facilities with healthy vending contracts had significantly healthier vending product profiles compared to facilities with conventional contracts. On average, significantly less availability of unhealthy (DNS) products represented these healthier profiles. Vending profiles did not significantly differ based on higher quality contract health stipulations although sample size limited conclusions about this. Conclusion: Facilities with health stipulated in their contract differed from those without health stipulations. This suggests that healthy vending contracts (even with relatively generic stipulations) may be supportive of improved nutrition environments. / Graduate / 2019-03-29
613

Machine Learning and Adaptive Signal Processing Methods for Electrocardiography Applications

Perumalla, Calvin A. 22 June 2017 (has links)
This dissertation is directed towards improving the state of art cardiac monitoring methods and automatic diagnosis of cardiac anomalies through modern engineering approaches such as adaptive signal processing, and machine learning methods. The dissertation will describe the invention and associated methods of a cardiac rhythm monitor dubbed the Integrated Vectorcardiogram (iVCG). In addition, novel machine learning approaches are discussed to improve diagnoses and prediction accuracy of cardiac diseases. It is estimated that around 17 million people in the world die from cardiac related events each year. It has also been shown that many of such deaths can be averted with long-term continuous monitoring and actuation. Hence, there is a growing need for better cardiac monitoring solutions. Leveraging the improvements in computational power, communication bandwidth, energy efficiency and electronic chip size in recent years, the Integrated Vectorcardiogram (iVCG) was invented as an answer to this problem. The iVCG is a miniaturized, integrated version of the Vectorcardiogram that was invented in the 1930s. The Vectorcardiogram provides full diagnostic quality cardiac information equivalent to that of the gold standard, 12-lead ECG, which is restricted to in-office use due to its bulky, obtrusive form. With the iVCG, it is possible to provide continuous, long-term, full diagnostic quality information, while being portable and unobtrusive to the patient. Moreover, it is possible to leverage this ‘Big Data’ and create machine learning algorithms to deliver better patient outcomes in the form of patient specific machine diagnosis and timely alerts. First, we present a proof-of-concept investigation for a miniaturized vectorcardiogram, the iVCG system for ambulatory on-body applications that continuously monitors the electrical activity of the heart in three dimensions. We investigate the minimum distance between a pair of leads in the X, Y and Z axes such that the signals are distinguishable from the noise. The target dimensions for our prototype iVCG are 3x3x2 cm and based on our experimental results we show that it is possible to achieve these dimensions. Following this, we present a solution to the problem of transforming the three VCG component signals to the familiar 12-lead ECG for the convenience of cardiologists. The least squares (LS) method is employed on the VCG signals and the reference (training) 12-lead ECG to obtain a 12x3 transformation matrix to generate the real-time ECG signals from the VCG signals. The iVCG is portable and worn on the chest of the patient and although a physician or trained technician will initially install it in the appropriate position, it is prone to subsequent rotation and displacement errors introduced by the patient placement of the device. We characterize these errors and present a software solution to correct the effect of the errors on the iVCG signals. We also describe the design of machine learning methods to improve automatic diagnosis and prediction of various heart conditions. Methods very similar to the ones described in this dissertation can be used on the long term, full diagnostic quality ‘Big Data’ such that the iVCG will be able to provide further insights into the health of patients. The iVCG system is potentially breakthrough and disruptive technology allowing long term and continuous remote monitoring of patient’s electrical heart activity. The implications are profound and include 1) providing a less expensive device compared to the 12-lead ECG system (the “gold standard”); 2) providing continuous, remote tele-monitoring of patients; 3) the replacement of current Holter shortterm monitoring system; 4) Improved and economic ICU cardiac monitoring; 5) The ability for patients to be sent home earlier from a hospital since physicians will have continuous remote monitoring of the patients.
614

Intelligent estimation of web break sensitivity in paper machines

Ahola, T. (Timo) 16 January 2006 (has links)
Abstract The ambition to increase the production of paper has made paper machine runnability widely studied in recent decades. Paper machine runnability is often measured by the number of web breaks in comparison with paper machine speed. When runnability is good, a machine can be run at the desired speed with the least possible number of breaks. Web break sensitivity means the number of breaks in a day, which can also be understood as a measurement of paper machine runnability. This study presents an application for the evaluation of web break sensitivity in a paper machine. A web break sensitivity indicator was built using the basic principles of case-based reasoning with a linguistic equations approach and basic fuzzy logic. The indicator combines on-line measurement data with expert knowledge and provides a continuous indication of break sensitivity. Web break sensitivity defines the current operating situation at the paper mill and provides new information to operators. Web break sensitivity is presented as a continuous signal with information about actual web breaks depicted as an eight-hour trend. The trend shows how the situation has developed and the current value gives a prediction for the next 24 hours if the situation stays as it is now. Together with information about the most important variables, this prediction gives operators enough time to react to the changing operating situation. From the methodological point of view, a new tool for building case-based reasoning applications for other purposes was also tested and found to be suitable for diagnostic applications.
615

A comparison of machine learning techniques for hand shape recognition

Foster, Roland January 2015 (has links)
>Magister Scientiae - MSc / There are five fundamental parameters that characterize any sign language gesture. They are hand shape, orientation, motion and location, and facial expressions. The SASL group at the University of the Western Cape has created systems to recognize each of these parameters in an input video stream. Most of these systems make use of the Support Vector Machine technique for the classification of data due to its high accuracy. It is, however, unknown how other machine learning techniques compare to Support Vector Machines in the recognition of each of these parameters. This research lays the foundation for the process of determining optimum machine learning techniques for each parameter by comparing Support Vector Machines to Artificial Neural Networks and Random Forests in the context of South African Sign Language hand shape recognition. Li, a previous researcher at the SASL group, created a state-of-the-art hand shape recognition system that uses Support Vector Machines to classify hand shapes. This research re-implements Li’s feature extraction procedure but investigates the use of Artificial Neural Networks and Random Forests in the place of Support Vector Machines as a comparison. The machine learning techniques are optimized and trained to recognize ten SASL hand shapes and compared in terms of classification accuracy, training time, optimization time and classification time.
616

Evaluation of commercial purge compounds on a laboratory film blower

Govender, Morgan 07 September 2005 (has links)
Purging compounds allow for rapid colour and material changes in plastics converting machines. They have both a cleaning and a purging action. The cleaning action refers to the removal of contaminants, e.g. carbon deposits, from the die, barrel and extruder-screw surfaces. This mechanism relies on conventional detergency in combination with high wall shear stresses. The purging action refers to the observed narrowing in the residence time distribution and is less well understood. The action of a purge compound may encompass both the cleaning and purging mechanisms in order to achieve the desired effect. In industry the effectiveness of a purge is determined by a visual observation of the extrudate. Therefore, a scientific method was required to quantitatively determine the efficiency of each purging mechanism under a set of fixed experimental conditions. In this study, a method was developed using a laboratory film-blower, which made use of a phthalocyanine blue pigment to impart colour to the film produced. The method was used to test the efficiency of various commercial purge compounds in switching the colour of film from blue to clear. The analysis was achieved by measuring the residual pigment concentration in the blue polymer film using a UV -Visible spectrophotometer. Commercial purge compounds function by means of various mechanisms such as filler abrasion, solvent dissolution, the dislodging of deposits with the aid of surfactants, etc. This study also considered the use of slip additives as an additional purging mechanism. In proposing that slip additives can contribute to a purging action, several slip additives where tested in polyethylene (PE), polypropylene (PP) and acrylonitrile butadiene styrene (ABS). The slip additives polypropylene wax and polyamide showed a significant increase in the MFI of PE whereas the additives polar wax and polyamide exhibited a slight increase in MFI of PP. Three additives, namely, polyamide, polypropylene wax and polar wax had showed noticeable improvement on the MFI of ABS. The slip additives that showed a significant improvement in polyethylene were tested together with six different commercial purge compounds. These compounds were tested for their colour change efficiency using polyethylene and switching from blue to clear in a laboratory film blower. It was found that the slip mechanism contributes very little to the purging action. Polymeric materials tend to adhere to hot metal surfaces. When the material continues to adhere to the metal after cooling down, cleaning of the processing equipment becomes very difficult. A purge manufactured by the CSIR, Pretoria, exhibited this problem. This study also covers an investigation into overcoming the adhesion problem of this purging compound. / Dissertation (MSc (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted
617

Model-Oriented Tracing Language: Producing Execution Traces from Tracepoints Injected into Code Generated from UML Models

Aljamaan, Hamoud January 2015 (has links)
This thesis investigates the building of a textual tracing language that operates at the model level to allow trace specification of textually modeled UML constructs. Current tracing approaches focus on manually injecting tracepoints into targeted systems at the source code level. Such approaches are useful in code-centric development styles where the majority of the code is handwritten. However, in the case of Model Driven Development (MDD), where models are utilized to generate some or all of the code, current tracing technology results in low level trace specification and generation of execution traces that are not aware of or linked to the originating model-level constructs. Dynamic analysis hence becomes harder for a modeler adopting an MDD approach. This field, which we call model-oriented tracing, is currently immature, with little pre-existing research. In this thesis, we present a textual model-level tracing language, implemented as part of Umple, that overcomes some of the limitations of existing tracing methods. The language facilitates model-level tracing, in a fashion very similar to code tracing. The language, which we call MOTL (Model-Oriented Tracing Language) allows tracing of UML associations, attributes and state machines. Constraints can be imposed to limit the scope of tracing. As a result of this work, modelers will gain the ability to specify traces of UML constructs at the model level without the need to modify the generated code, and then generate execution traces when the generated system is run. The resulting trace links back to the model constructs. Modelers can choose from among several tracing technologies including basic file or console output, Java logging framework, Log4J and LTTng. This thesis defines the language syntactically and semantically. Model-Driven Development (MDD) and Test-Driven Development (TDD) were followed to implement the language architecture to ensure high quality code generation. MOTL was used in the development in two of Umple subprojects. An empirical evaluation was conducted to evaluate the language’s usability.
618

Development of canned line-start rim-driven electric machines

Tuohy, Paul Michael January 2011 (has links)
Electric machines are being deployed in industrial applications where previously only mechanical systems were considered, as environmental concerns from burning fossil fuels and energy costs are becoming a more dominant factor in system design considerations. Electric machines offer greater operational flexibility and typically higher efficiencies. There has therefore been a growing demand to develop electric machines to replace traditional mechanical systems in a number of industrial applications. One such suitable electric machine topology is the 'direct-drive' machine. These machines can be used where implementation does not require a high operating speed, therefore eliminating the necessity of a gearbox. Furthermore, direct-drive machines offer a number of advantages including reductions in through-life costs, noise and vibration, and overall system volume. This thesis explores the development of direct-drive rim-driven machines, constructed by integrating a propeller with the electric machine that is driving it, by mounting the machine directly around the outside of the propeller. A novel machine topology was developed by integrating a conducting-can onto the rotor structure capable of producing induction torque, to create a motor that can start directly from the main electric supply. This eliminated the need for a power electronic converter, gearbox and complicated drive shafts arrangement, for use in applications where only a low duty cycle of operation was required such as secondary propulsion systems for marine applications or where safety and reliability is of significant importance. A number of other industrial applications that may benefit from this canned rim-driven topology were also identified including seal-less pumps and 'run-of-the-river' generators. Permanent-magnet and induction motor topologies operating in fluid environments were investigated, using finite element analysis and thermal analysis techniques, to examine and optimise the design of the rim-driven topology for a specific operational requirement, in each industrial application area identified. A 30 kW canned line-start rim-drive induction motor was designed and developed for use as a bi-directional thruster on-board a tidal stream turbine. A novel induction motor topology was developed utilising only a conducting-can on the rotor, which eliminated the need for a traditional squirrel-cage, due to the ratio of the relatively large mean air-gap diameter to the small output power requirement; creating a simple yet reliable direct-drive canned induction motor. The design of this motor was manufactured and successfully tested to validate the design process.
619

Separation and recognition of connected handprinted capital English characters

Ting, Voon-Cheung Roger January 1986 (has links)
The subject of machine recognition of connected characters is investigated. A generic single character recognizer (SCR) assumes there is only one character in the image. The goal of this project is to design a connected character segmentation algorithm (CCSA) without the above assumption. The newly designed CCSA will make use of a readily available SCR. The input image (e.g. a word with touching letters) is first transformed (thinned) into its skeletal form. The CCSA will then extract the image features (nodes and branches) and store them in a hierarchical form. The hierarchy stems from the left-to-right rule of writing of the English language. The CCSA will first attempt to recognize the first letter. When this is done, the first letter is deleted and the algorithm repeats. After extracting the image features, the CCSA starts to create a set of test images from the beginning of the word (i.e. beginning of the description). Each test image contains one more feature than its predecessor. The number of test images in the set is constrained by a predetermined fixed width or a fixed total number of features. The SCR is then called to examine each test image. The recognizable test image(s) in the set are extracted. Let each recognizable test image be denoted by C₁. For each C₁, a string of letters C₂, C₃, CL is formed. C₂ is the best recognized test image in a set of test images created after the deletion of C₁ from the beginning of the current word. C₃ through CL are created by the same method. All such strings are examined to determine which string contains the best recognized C₁. Experimental results on test images with two characters yield a recognition rate of 72.66%. Examples with more than two characters are also shown. Furthermore, the experimental results suggested that topologically simple test images can be more difficult to recognize than those which are topologically more complex. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
620

Aplicação da técnica de moiré em medições dinâmicas / Application of moiré technique in dynamic measurement

Silva, Marcos Valério Gebra da, 1971- 26 August 2018 (has links)
Orientadores: Inácio Maria Dal Fabbro, Antonio Carlos Loureiro Lino / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-26T12:42:52Z (GMT). No. of bitstreams: 1 Silva_MarcosValerioGebrada_D.pdf: 4641823 bytes, checksum: ad2a00015d9cecbe7670eac31c98b827 (MD5) Previous issue date: 2014 / Resumo: A medição estática de sólidos tridimensionais tem recebido uma grande atenção da comunidade científica. Porém, há também a possibilidade de serem feitas essas medições em condições dinâmicas, que ainda são pouco exploradas, mas que apresentam ampla gama de aplicações. Como exemplo, o estudo do fenômeno de vibração, geralmente associado a estruturas mecânicas tais como elementos de máquinas. Estudo sobre as tensões e deformações sofridas por corpos vegetais sob condições dinâmicas também são necessárias. Tendo em vista tais deficiências técnicas na área. Nota-se a importância de estudos específico, os quais podem ser levados a cabo com o suporte técnico de métodos ópticos, os quais permitem a medição de deformações, movimentos e posições relativas de elementos de máquinas em ensaios dinâmicos não destrutivos dentre outros. Entre os métodos perfilométricos mostrados na literatura, a Técnica de Moiré se mostra como uma ferramenta científica confiável, considerada rápida, de baixo custo e exequível, motivo pelo qual esse método foi selecionado para conduzir este trabalho, especificamente o método conhecido como "Moiré de Projeção com Deslocamento de Fase". Softwares específicos de uso gratuito foram empregados nas análises das imagens para alcançar o objetivo do presente trabalho, identificado como a determinação do deslocamento transversal da linha elástica de uma lâmina engastada, excitada por um solenoide com controle de oscilação. Os princípios de medição e o modelamento matemático do sistema foram detalhados e apresentados no trabalho. Uma sistemática de calibração do sistema também foi apresentada e modelada juntamente com os aspectos relativos à implementação computacional do sistema os quais foram discutidos / Abstract: Three dimensional coordinates survey of solids in static conditions has received major attention from the scientific community. However, the broad applications of three dimensional measures of solids under dynamic conditions is closely associated to structure, machine elements, subjected to a variety of dynamic loading which forcibly includes vibrational impositions. Agricultural science exhibits a major variety of examples, including farm machinery, plant-machine mechanical relations, rural buildings and bridges, etc. This research work is devoted to the application of optical techniques to capture the three dimensional measures of bodies under vibrational loadings, which permit measuring deformation patterns, motion, relative positions, etc. Optical methods can be easily associated to mechanical tests as well as to stress-strain distribution. The selected optical method is identified as Phase Shift Projection Moiré which is included in the moiré family of optical methods. The selected structural member was identified as cantilever beam, more precisely a steel blade clamped at one of its end which is excited by a solenoid to vibrate. Frequency as well as amplitude can be controlled. Images captured from the vibrating body were processed by means of specific software. Measuring principles and the mathematical modeling, the calibration procedure and the computational implementation were detailed as well / Doutorado / Maquinas Agricolas / Doutor em Engenharia Agrícola

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