Dissertations / Theses on the topic 'Time characteristics'
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Ho, A. Y. K. "Time dependent characteristics in tablet compaction." Thesis, Open University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375495.
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A single punch tablet machine has been instrumented to measure top and bottom punch force and punch displacement. A system has been developed for instrumenting rotary tablet machines using radio telemetery techniques and compared with conventional instrumentation systems. It is shown that the positioning of the measuring devices is critical for accurate measurements of forces and punch displacement. Samples of Micro crystalline cellulose (Avicel PH-102) and various grades of Lactose have been characterised and their compaction properties measured by a variety of techniques including breaking strength, changes in bed density under compaction and stress relaxation. The properties were determined using a specially constructed laboratory compaction simulator capable of reproducing compaction events typical of full scale production. It is shown that none of the conventional indices of compaction behaviour adequately predict the compaction properties of materials as described by their breaking strength: force profile. A phenomenon is described whereby the measurement of maximum force is not coincidental with the measurement of maximum punch penetration. Using model materials it is suggested that these differences are due to the visco elastic and plastic components of materials during compression. A new index - rise time - (the time between the initiation of compression and the point of maximum force application) is proposed as a useful means of predicting the behaviour of pharmaceutical solids during compression.
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Kota, Naga Purna Kiran Kumar. "Analysis of Magnet Wire Life-time Characteristics." MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11022005-142744/.
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Magnet wires find many applications in modern world. Magnet wires used for the electrical insulation in fly-back transformers, solenoids, sensors, adjustable speed drives etc. are subjected to multistress aging factors such as electrical (high voltage, high frequency), thermal and other environmental stresses. Due to the action of these aging factors degradation and aging of the insulation will occur and thereby lead to reduced life-time or premature failure. In order to identify the most important factors affecting the life-time of the electrical insulation, the insulation must be evaluated under simulated service conditions. This study is done by performing accelerated aging tests at high electrical stresses, elevated temperatures, and often at combined electrical and thermal stresses, and at high frequencies. The electrical phenomena behind the breakdown of the insulation have been studied. In this study accelerated life tests are performed on AWG 40 magnet wire. Life-time characteristics, probability of failures, and life-time percentiles are determined.
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Hall, M. C. "Adaptive IIR filter algorithms for real-time applications." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234800.
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Firmino, Catarina Filipa Fernandes. "Why do part-time entrepreneurs transition to full time entrepreneurship?" Master's thesis, Instituto Superior de Economia e Gestão, 2015. http://hdl.handle.net/10400.5/10139.
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Mestrado em FinançasEmpreendedorismo a tempo parcial é frequentemente considerado como sendo o primeiro passo para ingressar no empreendedorismo a tempo integral. Este estudo tem como objetivo investigar quais os determinantes que sustentam a transição mencionada. Para a realização deste estudo recorremos a uma base de dados portuguesa, Quadros de Pessoal Os empreendedores portugueses que transitam a sua actividade empresarial em tempo parcial para tempo integral são predominantemente homens com idades entre os 50 e 60 anos. A transição para uma actividade em tempo integral é mais passivel de ocorrer em indivíduos com maior educação e sem experiencia prévia na indústria. Em relação às características das empresas, podemos afirmar que quanto maior o tamanho da empresa no momento da sua fundação, maior será também, a probabilidade de a mesma empresa transitar de uma actividade parcial para uma actividade em tempo integral.
Part-time entrepreneurship is often considered to be the first step to full-time entrepreneurship. This study investigates the reasons and characteristics that lead part-time entrepreneurs to transitions into full-time entrepreneurship. To sustain this research, we ran through a matched employer-employee Portuguese database. Part-time entrepreneurs who transition to full-time are predominantly men individuals with ages between 50 to 65 years. The transition into full-time entrepreneurship is more likely to occur for high educated individuals with no previous industry experience. Additionally individual with a lower tenure and higher hours worked are more likely to move into full-time entrepreneurship. In regard to the ventures' characteristics, we find that, the larger ventures' size at its foundation, the higher is the likelihood of transition into full-time entrepreneurship.
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Rumetshofer, Anna. "Playing the European Postal Code Lottery? : Analysis of Time to Market of new Drugs on the European Market." Thesis, Uppsala universitet, Nationalekonomiska institutionen, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-391498.
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This thesis seeks to investigate the vastly varying time to market of newly approved drugs across Europe. Firtsly, I use a country fixed effects model on data of newly approved drugs from 2014 to 2017 from 18 European countries. I investigate the correlations between medication specific characteristics and the launch time and find that drugs intended to treat HIV, rheumatism or hepatitis are correlated with a faster launch time. Orphan drugs, though they represent a third of the dataset are found to be insignificantly correlated with time to market. Using a drug fixed effects model, I research important country characteristics in relation to the launch time and find that countries with higher imports of medications are correlated with a quicker time to market. Countries with larger medication export sectors experience a longer waiting time, which could be linked to companies trying to hinder the parallel export of new drugs.
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Wang, Min. "Characteristics of item response time for standardized achievement assessments." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5674.
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Response time (RT) data are able to provide unique insight into both items and examinees regarding speededness and time-demand and should be incorporated into test development practice. To allow test developers to utilize RT information, item RT needs to be summarized into point estimate(PE)(s) that can be understood by content specialists and saved into the item pool. The recent expansion of online testing in K-12 achievement assessments brings opportunities and challenges for measurement experts to investigate and utilize RT information in a context different from that in the majority of literature, in which licensing and certification tests, graduate admission tests, and other applications that incorporate computer-adaptive testing. Using empirical data from four tests in two grade levels of a K-12 standardized achievement assessment, this study explored the empirical distributions of item RT and their fit to five probability distributions, the characteristics of four item RTPEs, and the relationships between item RTPEs and eight item attributes. Based on the principal findings across tests and grades, the empirical distributions of item RT presented widely variable shapes and did not fit any of the five proposed probability distributions; the 90th quantile showed its important capability of capturing and avoiding speededness issues; and the associations between item RTPEs and item attributes proved to be mixed.
The generally idiosyncratic findings of this study call for a different perspective and approach to explore RT data and call for more empirical studies to enlighten test development practice in the K-12 standardized achievement assessment field.
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Cicatelli, Giancarlo. "Time warying wake flow characteristics behind turbine blade wakes." Doctoral thesis, Universite Libre de Bruxelles, 1998. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212070.
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Kee, Charmaine. "Time-averaged and real-time velocity characteristics of the screw wash of a manoevering ship." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486226.
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Experimental investigations of the velocity characteristics related to turbulent propeller-jet flow were carried out. Laser Doppler Anemometry (LDA) was used as the measurement technique. The investigations were performed in a free-surface tank, large enough to allow the unhindered expansion of unconfined propeller jets at bollard-pull. Comprehensive time-averaged (mean) and instantaneous real-time (blade-to- blade) velocity measurements were taken to assess the magnitude and location of the velocities that produce serious seabed scour. The results identify that the propeller blades play an important role in the development of the instantaneous velocity fields up to a downstream distance of two propeller diameters. Beyond this distance, the time-averaged form of measurement resolved all necessary information regarding the axial, radial and rotational velocity components. Establishing methods through which the characteristics of all three-velocity components can be determined using linear regression techniques has been carried out to extend the applications of existing semi-empirical equations. In the absence of suitable linear approximations of the main velocity characteristics, Artificial Neural Network (ANN) programmes were developed as an alternative method of determining the three-dimensional flow fields of a diffusing propeller jet produced in the confines of a harbour basin.
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Virebrand, Marcus. "Real-time monitoring of voice characteristics usingaccelerometer and microphone measurements." Thesis, Linköpings universitet, Reglerteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69760.
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VoxLog is a portable voice accumulator, that uses both an accelerometer that measures skin vibrations and a regular microphone to collect data. The goal of the thesis was to implement and evaluate methods that based on this data estimate the three different voice parameters fundamental frequency, phonation and soundpressure level. For pitch, three different methods were evaluated. The different methods all require relatively low computational power since the goal was to implement at least one of them on the digital signal processor in the VoxLog. The results from these evaluations show that the best estimations of pitch were made with a FFT-based approach that uses phase information to get an estimation with high frequencyresolution. Phonation is estimated with an energy based voice activity detection method.This estimation is then used to choose when sound pressure level should be estimated. Here one of the main problems was to make a distinction between when sound pressure level should be estimated for the wearer of the VoxLog or when an estimation should be made for the background noise. This was solved by implementing a time window before and after phonation were neither is estimated. For both pitch and sound pressure level a feedback functionality was implemented. The feedback is given to the user via vibrations in the VoxLog, the feedback is given when estimated parameters break set limits on pitch or sound pressure level.
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Simas, Maria Joao Correia de 1966. "Lag-time characteristics in small watersheds in the United States." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282155.
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Time is an important element in hydrologic design. Most hydrologic models require a watershed characteristic that reflects the timing of runoff. The time parameter used in this study was lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff. Lag times were evaluated from rainfall-runoff data in over 40,000 events in 116 small watersheds in the United States. The watersheds ranged from 0.243 to 3490 acres, with periods of rainfall-runoff records from 3 to 58 years. Rainfall-runoff event characteristics were used to determine a unique value of lag time for each storm. A tendency towards a constant value of lag time for the "bigger" storms was observed, "bigger" meaning higher values of either previous 48-hour rainfall, average effective rainfall intensity, average runoff intensity, or peak flow. The variable peak flow best showed this tendency; higher peak flow was associated with constant lag time in over 90% of the watersheds. Several hydrologic relationships involving lag time previously described in the literature were not verified in this study. Watershed characteristics were evaluated as "predictors" of lag time within a given watershed. The geomorphic variables used were area, length, width, slope, and storage coefficient (Curve Number). All variables were significant in explaining the variation of lag time by the regression analysis. The watersheds were divided into groups to try to explain the variation of lag time between watersheds. Management practices, geographical region, and the tendency toward constant value of lag time for the "bigger" storms had significant effects in the regression analyses, whereas land use and hydrologic behavior did not. When only the watersheds with the tendency described above were used, no groupings significantly improved the regression equations. Rainfall-runoff data should be used to compute lag time directly, especially for the bigger storms. If data are insufficient, regression predictions can be improved by grouping watersheds by regions and management practices. Width, slope and Snat are the best variables for prediction of lag time. The multiple linear regression model developed in this study had a higher coefficient of determination than other models in the literature.
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Burke, Nicholas Allan. "Travel time and flow characteristics of a small stream system." Thesis, Heriot-Watt University, 2002. http://hdl.handle.net/10399/426.
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Ramsey, Michael W., G. Gregory Haff, Ann M. Kinser, Jenna M. Kraska, Margaret E. Stone, William A. Sands, H. Hasegawa, and Michael H. Stone. "Isometric and Dynamic Force-time Curve Characteristics of Collegiate Throwers." Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etsu-works/4099.
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Tannous, Kareem Atalla. "Impact of Mortgage Characteristics on Retail Mortgage Transaction Completion Time." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5271.
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In the mortgage industry, many mortgage lenders cannot manage mortgage workflow systems while meeting and exceeding organizational objectives. Organizations with an above-industry average turnaround time (ATT) to complete a retail mortgage transaction (RMT) from origination to funding experience revenue losses. Grounded in the proposition that mortgage loan purpose (MLP), mortgage loan type (MLT), and subject property type (SPT) impact ATT to complete an RMT, the purpose of this causal-comparative study was to assess the impact of MLP, MLT, and SPT on ATT to complete an RMT. Using archival data records (N = 146) from a selected mortgage institution in the state of Florida, the results of the 2 x 2 x 2 factorial ANOVA showed that there were no main or interaction effects F(5,140) = 0.42, p = .83. Implications for social change include the possibility for mortgage lenders to implement improved workflow processes to reduce costs and improve efficiency metrics and intrinsic value, thereby benefitting organizational stakeholders such as employees and consumers.
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Brooke, Hannah Louise. "Time-segment specific physical activity : characteristics and changes in youth." Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708700.
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Sucic, Victor. "Parameters Selection for Optimising Time-Frequency Distributions and Measurements of Time-Frequency Characteristics of Nonstationary Signals." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15834/.
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The quadratic class of time-frequency distributions (TFDs) forms a set of tools which allow to effectively extract important information from a nonstationary signal. To determine which TFD best represents the given signal, it is a common practice to visually compare different TFDs' time-frequency plots, and select as best the TFD with the most appealing plot. This visual comparison is not only subjective, but also difficult and unreliable especially when signal components are closely-spaced in the time-frequency plane. To objectively compare TFDs, a quantitative performance measure should be used. Several measures of concentration/complexity have been proposed in the literature. However, those measures by being derived with certain theoretical assumptions about TFDs are generally not suitable for the TFD selection problem encountered in practical applications. The non-existence of practically-valuable measures for TFDs' resolution comparison, and hence the non-existence of methodologies for the signal optimal TFD selection, has significantly limited the use of time-frequency tools in practice. In this thesis, by extending and complementing the concept of spectral resolution to the case of nonstationary signals, and by redefining the set of TFDs' properties desirable for practical applications, we define an objective measure to quantify the quality of TFDs. This local measure of TFDs' resolution performance combines all important signal time-varying parameters, along with TFDs' characteristics that influence their resolution. Methodologies for automatically selecting a TFD which best suits a given signal, including real-life signals, are also developed. The optimisation of the resolution performances of TFDs, by modifying their kernel filter parameters to enhance the TFDs' resolution capabilities, is an important prerequisite in satisfying any additional application-specific requirements by the TFDs. The resolution performance measure and the accompanying TFDs' comparison criteria allow to improve procedures for designing high-resolution quadratic TFDs for practical time-frequency analysis. The separable kernel TFDs, designed in this way, are shown to best resolve closely-spaced components for various classes of synthetic and real-life signals that we have analysed.
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Moody, Erin E. "Changes in Women's Self-Employment Choices Over Time." Miami University Honors Theses / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1178043153.
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Book, Scott Allan. "Improving software characteristics of a real-time system using reengineering techniques." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA283659.
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Munasinghe, Ranjani. "Effect of hydraulic retention time on landfill leachate and gas characteristics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25123.pdf.
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Hess, Wolfgang. "Time-variant binaural activity characteristics as indicator of auditory spatial attributes." Berlin dissertation.de, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2926447&prov=M&dok_var=1&dok_ext=htm.
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Friel, Shaun. "Variation of the friction characteristics of road surfacing materials with time." Thesis, Ulster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603534.
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The lifespan of asphalt surfacing materials can vary from a very short duration, when temporary surfacing is considered, to up to 25 years for permanent surfacings. Throughout their lifespan the surfacings are expected to contribute to the provision of adequate levels of friction. The purpose of this research is to examine the variation of friction characteristics of road surfacing materials with time. The asphalt industry has undergone considerable change over the past two decades. This has seen the dominance of hot rolled asphalt and bituminous macadams (now asphalt concrete) being replaced by a spectrum of asphalt mixes specifically designed to offer a wider range of enhanced characteristics. Skidding resistance has remained as a priority requirement. Research has highlighted that there are distinct periods during the life of asphalt road surface materials. The existing standards are based on an equilibrium period during which there is seasonal variation with an overall downward trend to a value at which the surface warrants investigation prior to possible resurfacing or some other type of treatment. For some materials, there is an initial period of lower than expected skidding resistance found to last from a number of days, weeks to months and is termed early life. The majority of laboratory studies undertaken in this thesis were designed to reflect either real or hypothetical scenarios that could be encountered on an in-service highway surface. The programme of work considered the development of skid resistance for a range of surfacing materials from initial compaction until they have reached their equilibrium and are failing for different reasons. There were distinct generic relationships and the development of friction properties has different timelines depending on factors such as aggregate type, asphalt type, bitumen type and stressing conditions. The findings of the research will necessitate the revision of current Irish standards that will bring it closer in line with other European countries. This will probably involve the use of smaller stone size mixes and lowering the requirements for texture depth. It is anticipated that the improved understanding of the implications of poor practise will lead to better quality road surfaces in Ireland.
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Sianaki, A. H. "Parametric identification of squeeze-film bearing characteristics : a continuous time approach." Thesis, University of Edinburgh, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.661888.
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Turetta, Felipe Magno da Silva. "Analysis of pilot's reaction time with alerting systems characteristics and workload." Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3047.
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Uma análise sobre a percepção de pilotos de alertas em ``cockpits`` de uma aeronave civil é conduzida para melhorar o projeto de sistemas de alertas aeronáuticos e ``cockpits``. Atualmente o projeto de sistemas de alerta é feito usando principalmente requisitos de aeronavegabilidade e melhores práticas de engenharia, mas poucos dados quantitativos são empregados. O intuito deste trabalho é prover mais informações quantitativas sobre a percepção dos pilotos, para usar-se no processo de projeto de ``cockpits``. Inicialmente o ambiente do ``cockpit`` é estudado usando o modelo de fatores humanos SHELL para se identificar quais fatores poderiam afetar a percepção dos pilotos. Posteriormente os fatores são priorizados e um experimento projetado e executado usando um dispositivo de simulação de voo em um ambiente próximo do real. Um grupo de 7 pilotos civis é exposto a quatro pontos de teste totalizando 28 pontos experimentais cujos resultados são analisados. Conclusões importantes e informações são descobertas sobre a magnitude dos tempos de reação dos pilotos dependendo do tipo de alerta mostrado e a situação operacional considerada. Estes são descritos em detalhes neste trabalho. Adicionalmente, após correlacionar os resultados, a importância de alguns fatores torna-se evidente para garantir a percepção dos alertas.
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Tian, Lin. "Analysis of Time-Varying Characteristics of Simulated Turbulence in Wind Tunnel." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/33717.
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Eight roughness configurations in Clemson boundary layer wind tunnel are presented. For these configurations, flow parameters such as turbulent intensities, integral length scales, large- and small- scale turbulence, and spectra of velocity components of the wind are obtained and studied to the simulated turbulence. At the same time, new analyzing tools, orthogonal wavelet techniques, are applied to provide additional information in time domain. This makes it possible to study the intermittency event, one important characteristic associated with pressure peak activities in turbulence. Three parameters, scale energy, intermittency factor and intermittency energy are defined. Variation of these quantities as a result of different configuration is discussed. Finally, the corresponding variations in measured pressure peaks in relation with the variations of configuration as well as with the intermittency parameters are investigated. The work here is of important significance for future wind tunnel and field data comparison, and this could help to find the best simulation among all configurations.Master of Science
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Alshatshati, Salahaldin Faraj. "Estimating Envelope Thermal Characteristics from Single Point in Time Thermal Images." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1512648630005333.
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Lewis, William D. "An aeroelastic model structure investigation for a manned real-time rotorcraft simulation." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13037.
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Garcia, Mendoza Jesus Guillermo. "Lag Time Characteristics of Small Arid and Semiarid Watersheds in the Southwestern United States." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311345.
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An evaluation for Lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff, was performed for seven small watersheds in the Southwestern United States. The size of these watersheds range in size from 0.33 to 4.37 ha. The evaluation period goes from 2000 to 2010. This evaluation was compared versus 28 lag time equations.The USDA-ARS Southwest Watershed Research Center has developed an electronic data processing system where rainfall and runoff data is collected from sensors in the field and are transmitted to computers in the office.Prior to these data sets there were no measurable rainfall and runoff data. This digital data is generated by means of synchronized clocks in rain gages and flumes. As a result, the data from this electronic processing system offers a unique opportunity for hydrologic research. This infrastructure is a characteristic not often available in many other sites and a condition not enjoyed in previous investigations.There are several definitions of lag time depending on what particular time period is used to describe the occurrence of unit rainfall and runoff. But, time parameters currently lack commonly-accepted standard definitions.The various definitions for time parameters such as Lag Time, Time of Concentration, Time to Peak, Equilibrium Time and others, sometimes, are used interchangeably. Another aspect is that in Lag time determination, centers of mass play a critical role. This study found out that depending of the loss model chosen to estimate rainfall excess, it shall influence the determination of center of mass and hence the lag time.Some negative values were obtained for lag time when measured from peak of runoff to centroid of effective rainfall. However, in the lag time definition from centroid of effective rainfall to centroid of direct runoff, negative values were not obtained.One field in particular, time parameters currently lacks commonly-accepted standard definitions. This has become a source of profound confusion in this branch of science to the point where teams of scientists writing about and discussing hydrological Time Parameters can be compared to the aftermath at the Tower of Babel.
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Kato, T., H. Shimizu, Y. J. Tang, N. Hayakawa, Y. Yokomizu, and T. Matsumura. "Quench current level-time characteristics of AC insulated multi-strand superconducting cables." IEEE, 1997. http://hdl.handle.net/2237/6805.
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Collins, Marie Antoinette. "Characteristics and workload of full-time faculty in baccalaureate dental hygiene programs." Click here to access dissertation, 2006. http://www.georgiasouthern.edu/etd/archive/summer2006/marie_a_collins/collins_marie_a_200608_edd.pdf.
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Thesis (Ed.D.)--Georgia Southern University, 2006."A dissertation submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Doctor of Education" ETD. Includes bibliographical references (p. 133-138) and appendices.
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Sarrazin-Delay, Chantal L. "Predicting time-to-ignition from stem fuel characteristics of fifteen herbaceous species." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ31469.pdf.
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Chow, Shue Loong. "The gestalt characteristics of experiences that extend over time: A further analysis." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485961.
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The literature on how people evaluate _th~ir sequential expe~.iences makes two contrasting observations. On the one hand, the literature suggests that some of the key findings, such as the preference for an improving sequence, are persistent effects. On the other hand, an emerging, critical literature has pointed out· that such effects are highly conditional on a number of factors, such as the sequence domain. The presence of such factors could moderate the preference for improvement.· The objective of the studies in this thesis was to explore the role of such factors on people's evaluations of sequences of delays. The results of the studies suggested that gestalt theories such as the preference for improvement in a sequence of delays are not always applicable, but instead conditional on many factors, such as the duration of delays, the degree to which delays prevented task achievement, and people's expectations of how delays are usually experienced. Key words: Gestalt characteristics, Sequences, Delays, Preference for improvement.
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Sole, Christopher J. "Analysis of Countermovement Vertical Jump Force-Time Curve Phase Characteristics in Athletes." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2549.
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The purposes of this dissertation were to examine the phase characteristics of the countermovement jump force-time curve between athletes based on jumping ability, examine the influence of maximal muscular strength on the countermovement jump force-time curve phase characteristics of athletes, and to examine the behavior of the countermovement jump force-time curve phase characteristics over the course of a training process in athletes of varying strength levels. The following are the major findings of these dissertations. The analysis of athletes by jumping ability suggested that proficient jumpers are associated with greater relative phase magnitude and phase impulse throughout the phases contained in the positive impulse of the countermovement jump force-time curve. Additionally, phase duration was not found to differ between athletes based on jumping ability or between male and female athletes. The analysis of athletes based on maximal muscular strength suggested that only unweighted phase duration differs between strong and less-strong athletes. Interestingly, in both investigations based on jumping ability and maximal strength indicated the relative shape of the stretching phase representing the rise in positive force was related to an athlete’s jumping ability (jump height). The results of the longitudinal analysis of countermovement jump force-time phase characteristics identified that these variables can be frequently assessed throughout a training process to provide information of regarding an athlete performance state. Furthermore, based on the contrasting behaviors of many of the countermovement jump force-time curve phase characteristics over time, an athlete’s level of muscular strength may influence how these characteristics are expressed in the context of a training process.
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Lewis, Arthur M. "Seasonal Hidden Markov Models for Stochastic Time Series with Periodically Varying Characteristics." PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/5056.
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Novel seasonal hidden Markov models (SHMMs) for stochastic time series with periodically varying characteristics are developed. Nonlinear interactions among SHMM parameters prevent the use of the forward-backward algorithms which are usually used to fit hidden Markov models to a data sequence. Instead, Powell's direction set method for optimizing a function is repeatedly applied to adjust SHMM parameters to fit a data sequence. SHMMs are applied to a set of meteorological data consisting of 9 years of daily rain gauge readings from four sites. The fitted models capture both the annual patterns and the short term persistence of rainfall patterns across the four sites.
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Ayzatskiy, N., A. Dovbnya, V. Zakutin, N. Reshetnyak, V. Romas'ko, I. Chertishchev, V. N. Boriskin, V. Mitrochenko, A. B. Galat, and I. Khodak. "Experimental investigation on the time characteristics of an electron beam formed in the magnetron gun with a secondari-emission cathode." Thesis, Национальный научный центр "Харьковский физико-технический институт" (ННЦ ХФТИ), 2007. http://openarchive.nure.ua/handle/document/9244.
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Vidigal, Mariana de Ribeiro Lopes e. Ferreira. "How well do portuguese part-time entrepreneurs perform?" Master's thesis, Instituto Superior de Economia e Gestão, 2014. http://hdl.handle.net/10400.5/7910.
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Mestrado em FinançasO propósito desta dissertação é examinar o desempenho dos empreendedores a tempo parcial, principalmente analisar sua sobrevivência. Recorremos a uma base de dados com dados do empregado-empregador (QP - "Quadros de Pessoal"), e selecionámos todas as novas empresas que se estabeleceram no período de 2000-2007, excluindo todas as organizações sem fins lucrativos, obtendo um total de 41,293 observações. As organizações sem fins lucrativos foram excluídos, porque este estudo incide sobre indivíduos que decidiram se envolver no empreendedorismo a tempo parcial como forma de obter um rendimento adicional. Um empreendedor a tempo parcial é uma pessoa que dedica o seu tempo livre a exercer uma actividade empresarial, enquanto mantém um trabalho regular. A nossa principal conclusão é que as características dos empresários de tempo parcial partilham algumas semelhanças com empresários a tempo integral, principalmente em termos de idade e tamanho da empresa.
The purpose of this study is to evaluate the performance of part-time entrepreneurs, more specifically evaluate their survival. We use an employer' employee dataset (QP - "Quadros de Pessoal"), we solemnly select all start-ups established between 2000 and 2007, and exclude nonprofit organizations, obtaining a total of 41,293 observations. The nonprofit organizations were excluded mainly because this study focused on individuals that decided to engage in part-time entrepreneurship as a way to gain an extra income. Part-time entrepreneurs are individuals who dedicate their spare time in engaging in entrepreneurial ventures while maintaining a regular job. Our major finding is that part-time entrepreneurs share some similarities with the full-time entrepreneur's features, mainly in terms of age and firm's size.
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Suozzo, Joseph C. "Being about our father's business characteristics of selected tentmaking entrepreneurs in South Asia /." Theological Research Exchange Network (TREN), 2000. http://www.tren.com.
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Parsafard, Mohsen. "Space-Time Transportation System Modelling: from Traveler’s Characteristics to the Network Design Problem." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6924.
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Traditional network design problems only consider the long-term stationary travel patterns (e.g., fixed OD demand) and short-term variations of human mobility are ignored. This study aims to integrate human mobility characteristics and travel patterns into network design problems using a space-time network structure. Emerging technologies such as location-based social network platforms provide a unique opportunity for understanding human mobility patterns that can lead to advanced modeling techniques. To reach our goal, at first multimodal network design problems are investigated by considering safety and flow interactions between different modes of transport. We develop a network reconstruction method to expand a single-modal transportation network to a multi-modal network where flow interactions between different modes can be quantified. Then, in our second task, we investigate the trajectory of moving objects to see how they can reveal detailed information about human travel characteristics and presence probability with high-resolution detail. A time geography-based methodology is proposed to not only estimate an individual’s space-time trajectory based on his/her limited space-time sample points but also to quantify the accuracy of this estimation in a robust manner. A series of measures including activity bandwidth and normalized activity bandwidth are proposed to quantify the accuracy of trajectory estimation, and cutoff points are suggested for screening data records for mobility analysis.
Finally, a space-time network-based modeling framework is proposed to integrate human mobility into network design problems. We construct a probabilistic network structure to quantify human’s presence probability at different locations and time. Then, a Mixed Integer Nonlinear Programming (MINLP) model is proposed to maximize the spatial and temporal coverage of individual targets. To achieve near optimal solutions for large-scale problems, greedy heuristic, Lagrangian relaxation and simulated annealing algorithms are implemented to solve the problem. The proposed algorithms are implemented on hypothetical and real world numerical examples to demonstrate the performance and effectiveness of the methodology on different network sizes and promising results have been obtained.
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Martens, Betsy Van der Veer Goodrum Abby. "Theories at work Functional characteristics of theories that facilitate their diffusion over time /." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.
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He, Congrong. "Airborne Particles in Indoor Residential Environment: Source Contribution, Characteristics, Concentration, and Time Variability." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16017/.
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The understanding of human exposure to indoor particles of all sizes is important to enable exposure control and reduction, but especially for smaller particles since the smaller particles have a higher probability of penetration into the deeper parts of the respiratory tract and also contain higher levels of trace elements and toxins. Due to the limited understanding of the relationship between particle size and the health effects they cause, as well as instrument limitations, the available information on submicrometer (d < 1.0 µm) particles indoors, both in terms of mass and number concentrations, is still relatively limited. This PhD project was conducted as part of the South-East Queensland Air Quality program and Queensland Housing Study aimed at providing a better understanding of ambient particle concentrations within the indoor environment with a focus on exposure assessment and control. This PhD project was designed to investigate comprehensively the sources and sinks of indoor aerosol particles and the relationship between indoor and outdoor aerosol particles, particle and gaseous pollutant, as well as the association between indoor air pollutants and house characteristics by using, analysing and interpreting existing experimental data which were collected before this project commenced, as well as data from additional experiments which were designed and conducted for the purpose of this project. The focus of this research was on submicrometer particles with a diameter between 0.007 - 0.808 µm. The main outcome of this project may be summarised as following: * A comprehensive review of particle concentration levels and size distributions characteristics in the residential and non-industrial workplace environments was conducted. This review included only those studies in which more general trends were investigated, or could be concluded based on information provided in the papers. This review included four parts: 1) outdoor particles and their effect on indoor environments; 2) the relationship between indoor and outdoor concentration levels in the absence of indoor sources for naturally ventilated buildings; 3) indoor sources of particles: contribution to indoor concentration levels and the effect on I/O ratios for naturally ventilated buildings; and 4) indoor/outdoor relationship in mechanically ventilated buildings. * The relationship between indoor and outdoor airborne particles was investigated for sixteen residential houses in Brisbane, Australia, in the absence of operating indoor sources. Comparison of the ratios of indoor to outdoor particle concentrations revealed that while temporary values of the ratio vary in a broad range from 0.2 to 2.5 for both lower and higher ventilation conditions, average values of the ratios were very close to one regardless of ventilation conditions and of particle size range. The ratios were in the range from 0.78 to 1.07 for submicrometer particles, from 0.95 to 1.0 for supermicrometer particles and from 1.01 to 1.08 for PM2.5 fraction. Comparison of the time series of indoor to outdoor particle concentrations showed a clear positive relationship existing for many houses under normal ventilation conditions (estimated to be about and above 2 h-1), but not under minimum ventilation conditions (estimated to be about and below 1 h-1). These results suggest that for normal ventilation conditions and in the absence of operating indoor sources, outdoor particle concentrations could be used to predict instantaneous indoor particle concentrations but not for minium ventilation, unless air exchange rate is known, thus allowing for estimation of the "delay constant". * Diurnal variation of indoor submicrometer particle number and particle mass (approximation of PM2.5) concentrations was investigated in fifteen of the houses. The results show that there were clear diurnal variations in both particle number and approximation of PM2.5 concentrations, for all the investigated houses. The pattern of diurnal variations varied from house to house, however, there was always a close relationship between the concentration and human indoor activities. The average number and mass concentrations during indoor activities were (18.2±3.9)×10³ particles cm-³ and (15.5±7.9) µg m-³ respectively, and under non-activity conditions, (12.4±2.7)x10³ particles cm-³ (11.1±2.6) µg m-³, respectively. In general, there was a poor correlation between mass and number concentrations and the correlation coefficients were highly variable from day to day and from house to house. This implies that conclusions cannot be drawn about either one of the number or mass concentration characteristics of indoor particles, based on measurement of the other. The study also showed that it is unlikely that particle concentrations indoors could be represented by measurements conducted at a fixed monitoring station due to the large impact of indoor and local sources. * Emission characteristics of indoor particle sources in fourteen residential houses were quantified. In addition, characterizations of particles resulting from cooking conducted in an identical way in all the houses were measured. All the events of elevated particle concentrations were linked to indoor activities using house occupants diary entries, and catalogued into 21 different types of indoor activities. This enabled quantification of the effect of indoor sources on indoor particle concentrations as well as quantification of emission rates from the sources. For example, the study found that frying, grilling, stove use, toasting, cooking pizza, smoking, candle vaporizing eucalyptus oil and fan heater use, could elevate the indoor submicrometer particle number concentration levels by more than 5 times, while PM2.5 concentrations could be up to 3, 30 and 90 times higher than the background levels during smoking, frying and grilling, respectively. * Indoor particle deposition rates of size classified particles in the size range from 0.015 to 6 µm were quantified. Particle size distribution resulting from cooking, repeated under two different ventilation conditions in 14 houses, as well as changes to particle size distribution as a function of time, were measured using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS), and a DustTrak. Deposition rates were determined by regression fitting of the measured size-resolved particle number and PM2.5 concentration decay curves, and accounting for air exchange rate. The measured deposition rates were shown to be particle size dependent and they varied from house to house. The lowest deposition rates were found for particles in the size range from 0.2 to 0.3 µm for both minimum (air exchange rate: 0.61±0.45 h-1) and normal (air exchange rate: 3.00±1.23 h-1) ventilation conditions. The results of statistical analysis indicated that ventilation condition (measured in terms of air exchange rate) was an important factor affecting deposition rates for particles in the size range from 0.08 to 1.0 µm, but not for particles smaller than 0.08 µm or larger than 1.0 µm. Particle coagulation was assessed to be negligible compared to the two other processes of removal: ventilation and deposition. This study of particle deposition rates, the largest conducted so far in terms of the number of residential houses investigated, demonstrated trends in deposition rates comparable with studies previously reported, usually for significantly smaller samples of houses (often only one). However, the results compare better with studies which, similarly to this study, investigated cooking as a source of particles (particle sources investigated in other studies included general activity, cleaning, artificial particles, etc). * Residential indoor and outdoor 48 h average levels of nitrogen dioxide (NO2), 48h indoor submicrometer particle number concentration and the approximation of PM2.5 concentrations were measured simultaneously for fourteen houses. Statistical analyses of the correlation between indoor and outdoor pollutants (NO2 and particles) and the association between house characteristics and indoor pollutants were conducted. The average indoor and outdoor NO2 levels were 13.8 ± 6.3 ppb and 16.7 ± 4.2 ppb, respectively. The indoor/outdoor NO2 concentration ratio ranged from 0.4 to 2.3, with a median value of 0.82. Despite statistically significant correlations between outdoor and fixed site NO2 monitoring station concentrations (p = 0.014, p = 0.008), there was no significant correlation between either indoor and outdoor NO2 concentrations (p = 0.428), or between indoor and fixed site NO2 monitoring station concentrations (p = 0.252, p = 0.465,). However, there was a significant correlation between indoor NO2 concentration and indoor submicrometer aerosol particle number concentrations (p = 0.001), as well as between indoor PM2.5 and outdoor NO2 (p = 0.004). These results imply that the outdoor or fixed site monitoring concentration alone is a poor predictor of indoor NO2 concentration. * Analysis of variance indicated that there was no significant association between indoor PM2.5 and any of the house characteristics investigated (p > 0.05). However, associations between indoor submicrometer particle number concentration and some house characteristics (stove type, water heater type, number of cars and condition of paintwork) were significant at the 5% level. Associations between indoor NO2 and some house characteristics (house age, stove type, heating system, water heater type and floor type) were also significant (p < 0.05). The results of these analyses thus strongly suggest that the gas stove, gas heating system and gas water heater system are main indoor sources of indoor submicrometer particle and NO2 concentrations in the studied residential houses. The significant contributions of this PhD project to the knowledge of indoor particle included: 1) improving an understanding of indoor particles behaviour in residential houses, especially for submicrometer particle; 2) improving an understanding of indoor particle source and indoor particle sink characteristics, as well as their effects on indoor particle concentration levels in residential houses; 3) improving an understanding of the relationship between indoor and outdoor particles, the relationship between particle mass and particle number, correlation between indoor NO2 and indoor particles, as well as association between indoor particle, NO2 and house characteristics.
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Joncic, John. "An empirical review of Canadian monetary aggregates, substitution, separability and time series characteristics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0020/MQ55154.pdf.
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Chang, David. "Temporary and permanent part-time workers : work differences explored using job characteristics theory /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09ARPS/09arpsc456.pdf.
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Wong, Ching-yin Juliana. "Voice onset time (VOT) characteristics of esophageal, tracheoesophageal and laryngeal speech of Cantonese." Click to view the E-thesis via HKU Scholars Hub, 2007. http://lookup.lib.hku.hk/lookup/bib/B42006119.
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Thesis (B.Sc)--University of Hong Kong, 2007."A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2007." Includes bibliographical references (p. 29-33). Also available in print.
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Garcez, Aurélio Dos Santos João Pedro. "Voluntary and involuntary mental time travel in dysphoria and depression : characteristics and mechanisms." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/22968.
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Mental time travel (MTT) refers to an individual’s ability to mentally travel through subjective time, autonoetically re-experiencing past events under the form of autobiographical memories (past MTT), and pre-experiencing events as future autobiographical representations (future MTT). MTT can occur voluntarily, whereby a past/future autobiographical event is subjectively experienced as an intended occurrence, or involuntarily, wherein such an event is subjectively experienced as an unintended outcome of which the individual is aware. Studies investigating MTT’s characteristics in dysphoria and depression show that dysphoric and depressed individuals produce more overgeneral and negative MTT events when compared to control groups. However, existing research has been limited to past and voluntary MTT events, with few studies investigating involuntary MTT and future MTT in dysphoria and depression. The overarching aim of the present research was to compare the phenomenological characteristics of MTT in dysphoric individuals vs. normal mood individuals (Study 1), and in clinically depressed individuals vs. never-depressed individuals (Study 2), with the purpose of furthering existing knowledge on MTT and its relation with dysphoria and Major Depressive Disorder. This aim was addressed by conducting two studies, using a 2 x (2 x 2) mixed-factorial design, with temporality (past vs. future events) and type of retrieval (voluntary vs. involuntary events) as within-subjects independent variables, and participant group as a between-subjects variable. In Study 1, Portuguese university students were categorised into a dysphoric (n=17) or a normal mood group (n=39) depending on their score on the Beck Depression Inventory (BDI-IA) – cutoff point (≥ 10). In Study 2, clinically diagnosed depressed patients (n=32) were recruited from a Portuguese hospital and matched for age and gender with never-depressed control participants (n=32) recruited from the community. The dependent variables tested were: level of spatiotemporal specificity, self-relevance, mood and physical impact, valence, and visual perspective of the MTT events produced. A diary methodology was used in both studies, with an open-ended time period that lasted for a minimum of two weeks, for participants to record their MTT events and grade them on the above mentioned variables using Likert-type ratings. Between seven and fourteen MTT events were produced for each of the four MTT conditions (past voluntary, past involuntary, future voluntary, future involuntary). Results showed that when compared to their respective control groups, depressed, but not dysphoric participants, exhibited a clear influence of mood on several of the phenomenological characteristics of MTT. In Study 1 there were no statistically significant differences in the specificity, negative valence, and mood/physical impact of the MTT events produced by dysphoric and normal mood participants. On the contrary, in Study 2, results partially supported a lower specificity and fully supported a greater negativity and mood/physical impact of MTT events in depressed individuals compared with never-depressed participants. Both studies supported the greater self-relevance of voluntary MTT events and partially supported the hypothesised effect of type of retrieval in specificity. These were the first studies to directly compare past and future, voluntary and involuntary MTT events in dysphoric and depressed individuals, addressing existing gaps in the literature. The key limitation is the relatively small sample size of both studies, however each participant was comprehensively assessed for at least two weeks, providing a rich set of reliable data. Despite limitations, this thesis provides novel pilot findings that help understand the similarities and differences between involuntary and voluntary, past and future MTT, as well as providing new information regarding the possible role of MTT in dysphoria and depression.
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Thomas, Kathy Wright. "Voice Onset Time Characteristics of Selected Phonemes in Young and Old Male Speakers." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc500707/.
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The purpose of the investigation was to compare mean voice onset time in young and old male subjects, as well as to examine variability of VOT productions with age for prevocalic bilabial, alveolar, and velar voiced and voiceless stop consonants. Forty-five Caucasion.males were divided equally into three.age groups. Ten tokens of six stimulus words were recorded and wide band spectrograms were made. Results of an analysis of variance revealed no significant differences in VOT with age when averages of the phonemes were used for analysis; however, a significant interaction between age and voiced phonemes was found when individual trials of phoneme productions were used for analysis.
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Gkritza, Konstantina. "Analysis of the characteristics of emergency vehicle operations in the Washington D.C. Region." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34632.
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Concerns about increased emergency vehicle response times in the Washington D.C. Region, especially during peak periods, have led to the implementation of signal preemption systems to facilitate the efficient and safe movement of emergency vehicles. However, to date only limited research has been carried out on the travel characteristics of emergency vehicles.
This paper presents an analysis of emergency vehicle characteristics to enhance our understanding of emergency vehicle operations and impacts and to assist public agencies and other stakeholders in the planning and deployment of emergency vehicle preemption systems. Emergency vehicle characteristics that merit special attention include temporal and spatial distribution of emergency vehicle travel; frequency and duration of preemption requests; platoon responses; and crashes involving emergency vehicles. Data on major corridors in Fairfax County, Virginia and Montgomery County, Maryland are used in the analysis.
The analysis indicates that such data are useful to assess the need for a preemption system along major arterials. Moreover, the analysis demonstrates the importance of considering emergency vehicle preemption impacts regarding delay to other vehicles. It is also important to note that there is some variability in the emergency vehicle characteristics depending on the proximity of a firehouse to an intersection and other factors. It is proposed that future efforts build upon this research to develop warrants to be used in determining the appropriateness of installing preemption systems at signalized intersections.Master of Science
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Westin, Kerstin. "Valuation of goods transportation characteristics : A study of a sparsely populated area." Doctoral thesis, Umeå universitet, Institutionen för geografi och ekonomisk historia, 1994. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-54419.
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This study describes how consumers and providers of transportation services in a sparsely populated area valuate different transportation characteristics and estimates how these valuations might affect the total goods flows and the flows on individual Origin-Destination links. It also tests Stated-Preference methods as a tool for valuating transportation characteristics. The hypothesis was that transportation consumers in sparsely populated areas are more sensitive to changes in the transportation characteristics cost and frequency than they are to changes in goods safety, time accuracy, and delivery time. The reason for this assumption was that the supply of transport modes and transport operators in these areas is limited in comparison to more urban areas. Acceptable transportation costs, in the sense that transportation is economically feasible, and possibilities to obtain a certain minimum transportation frequency are essential. It might, therefore, be necessary to renounce demands for time accuracy, goods safety, and delivery time. The results indicate that the consumers were most sensitive tp lowered distribution frequency. The probability of accepting a transportation service dropped by .19 when frequency decreased from three times to once per week. Changes in the characteristics delivery time and time accuracy were also significant. Reduced frequency would, from a consumer perspective, also result in the largest impact on the total goods. However, a cost increase of 25 percent and lower goods safety would result in a greater reduction of the total goods flow than would longer delivery time and lower time accuracy. The providers, on the other hand, were very sensitive to increased costs and lower revenues. A drop in quantity from 90 percent to 40 percent vehicle utilization was also significant. However, respondents in the strata 'private trucks' assigned more importance to changes in frequency and quantity. The largest effect on the total goods flow would be caused by a 25 percent cost increase. High demands on time accuracy would affect the goods flow more than would lowered revenue. A significant conclusion is that the Stated-Preference method used is an adequate tool in valuating transportation characteristics. However, great care must be taken in formulating the characteristics and levels used. Also, in addition to the characteristics tested in this study, there may be other characteristics that help explain the probability that consumers and providers in sparsely populated areas will accept a transportdigitalisering@umu
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Sridharan, Kousik Sarathy. "Real-time acquisition and analysis ofElectro-oculography signals." Thesis, Linköpings universitet, Biomedicinsk instrumentteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76734.
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Electro-oculography signals are corneo-retinal potentials that carry informationpertaining to eye movements. This information can be used to estimate drowsinesslevel of the subject which could provide interesting insights into research of acci-dent prevention. Of all features present, blink duration has been proved to be aneffective measure of drowsiness. The aim of this thesis work is to build a portablesystem to acquire and analyze electro-oculographic (EOG) signals in real-time.The system contains two sub-systems; a hardware sub-system that consists of thefilters, amplifiers, data acquisition card and isolation and the software sub-systemthat contains the program to acquire and analyze the signal and present the resultsto the observer. The filters were designed starting with simulation, implementa-tion on the prototype board, culminating in the design of a printed circuit board(PCB) and packaging. The complete software was written in PythonTMusing sev-eral relevant libraries for data processing. A text-based user interface was createdto enable easy user interaction. The results are graphically displayed in real-time. Ex-situ tests were done with two volunteers while in-situ test was done onone subject. The data from the in-situ tests showed "good signal quality" in a"noisy" environment concurring with the design specifications. To motivate theimportance of calibration, two calibration paradigms were used during ex-situtests, where one paradigm records only normal blinks while the other records longblinks and the results showed differences in detection and error rates. The obser-vations made from performance tests at various levels gave "satisfactory results"and proved the usefulness of the system for experimental purposes in-situ.
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Hancock, Jason. "Evaluation of the timing characteristics of various PET detectors using a time alignment probe." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18467.
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Time alignment is performed on a conventional PET scanner in order to reduce the noise in the image from undesirable interactions, called randoms. In time of flight scanners this alignment is even more critical in order to place the position of an annihilation accurately. Traditionally, the alignment is an iterative process done by adjusting time offsets and recording the count rate until it is maximized. We have designed and built a positron detector that can be placed in the PET scanner. This enables each crystal in the scanner to be aligned to the same event (the positron detection), providing a constant reference to each crystal. This both increases the accuracy of the alignment and the speed in which it can be done.L'alignement de temps est effectué sur un TEP conventionnelle pour réduire le bruit dans l'image causé par des interactions hasard. Dans les appareils utilisant le temps-de-vol, cet alignement est essentiel pour bien connaitre la position exacte de l'annihilation. Traditionnellement, l'alignement est un processus répétitif accompli en ajustant les décalés de temps et en enregistrant le taux de compte jusqu'il soit maximisé. Nous avons créé un détecteur de positron que nous pouvons placer l'intrieur du PET. Ceci nous permet d'aligner chaque cristal dans le scanner au même événement (la détection de positron), et de fournir une référence constante à chaque cristal. Ceci augmente la précision et la vitesse de l'alignement.
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Yu, Jun. "Empirical characteristics function in time series estimation and a test statistic in financial modelling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31169.pdf.
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Smit, Hendrik Christiaan. "Development of a time/temperature logging device to characterise the burning characteristics of biofuels." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6616.
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Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: A lab scale combustion unit was designed, in order to characterise the performance of various woody and wood-based biofuels commonly used for energy production, cooking and heating. The unit was constructed in a way that it could be repeatedly reused and provide similar testing conditions, such as airflow for all samples. The requirements were that it was big enough to contain a fire large enough to yield good time/temperature profiles and at the same time easy to handle, operate and clean. It also had to allow the insertion of the thermocouples and flue gas probe. Time / temperature profiles were obtained and O2, CO2 and CO levels in the flue gas determined for each biofuel. The samples consisted of the five most commonly used fuel wood species in the Western Cape, namely Rooikrans, Camelthorn, Bluegum, Black wattle and vine stumps and five processed products, namely wood pellets, wood briquettes, commercial charcoal, commercial briquettes and handmade briquettes. Combustion time/temperature profiles were obtained for all samples and characteristic values, such as the maximum temperature and coal temperature compared. This allowed an indication of which product performed better than others in the different combustion phases and is more suitable for different requirements, such as industrial heating, or domestic cooking. Even though Bluegum and Camelthorn performed best overall they were not necessarily suited, for example, for large scale industrial use. It was found that wood pellets and charcoal were the best biofuel for industrial purposes, whereas Rooikrans was found to be the best option for small scale use.
AFRIKAANSE OPSOMMING: ‘n Laboratoriumskaal verbrandingseenheid was ontwerp vir die toets en karakterisering van verskeie houtgebaseerde biomassa soorte algemeen in gebruik vir energie opwekking, kook en verhitting. Daar was besluit om ‘n eenheid te bou vir herhaalde gebruik wat die omstandinghede vir elke toets konstant kan hou, bv. ‘n damper om lugvloei deur die sisteem the beheer. Die eenheid moet groot genoeg wees om veilig ‘n groot genoeg vuur the bevat waarmee ‘n goeie tyd/temperatuur profiel verkry kan word, maar terselfdetyd klein genoeg wees om te hanteer, operateer en skoon te maak. Die eenheid moes ook voorsiening maak vir die insteek van die termostate en gas peilstif. Tyd/temperatuur profiele is verkry en O2, CO2 en CO vlakke in die uitlaatgas is bepaal vir elke bio-brandstof. Die monsters was saamgestel uit vyf van die mees algemeen gebruikte brandhout spesies in die Wes Kaap, naamlik Rooikrans, Kameeldoring, Bloekom, Swartwattel en wingerdstompies, asook vyf geprosesseerde produkte naamlik houtpille, houtbrikette, kommersiële steenkool, kommersiële brikette and handgemaakte brikette. Verbranding tyd/temperatuur profiele is verkry vir al die monsters en verteenwoord waardes is daarvan afgelees, bv. die maksimum temperatuur wat bereik is of die temperatuur waar die vlamme uitgesterf het en slegs koolhitte gemeet word. Hierdie profiele het dit moontlik gemaak om te identifiseer watter produk het beter gevaar as ander gedurende die verskillende verbrandingsfases en is beter gepas vir verskillende gebruike, bv. huishoudelike kook en verhitting. Resultate het gedui dat die Bloekom en Kameeldoring die beste gevaar het oor all die toetse heen, maar was nie noodwendig ideaal vir elke spesifieke doel nie. Dit was bevind dat die steenkool en houtpille die beste gepas is vir industriele gebruik en dat die Rooikrans beter geskik is vir huishoudelike en kleinskaalse gebruik.
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Maneri, Erin 1977. "Time domain characteristics of human force control in rejection of transient disturbances during movement." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/28335.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2004.Includes bibliographical references (p. 76-77).
Many tasks that humans successfully complete are more naturally represented in terms of their force requirements than their state (position or velocity) requirements. Yet the literature on force and timing is relatively underrepresented. This work was an attempt to clarify whether feedforward and/or feedback force control mechanisms might be available in human motor control. Subjects were trained and tested rejecting simple square pulse disturbance forces perpendicular to concurrent reaching movements. The data was analyzed with the goals of both verifying the feasibility of a proposed control model, and then clarifying the capabilities, limitations and properties of such a controller.
by Erin Maneri.
S.M.