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Theoretical Modeling of Cortisol SensorGordic, Milorad 27 October 2008 (has links)
This thesis describes the theoretical modeling of a response of an electrochemical BioMEMS sensor for detecting small amounts of cortisol hormone. The electrochemical sensor utilizes a catalyst enzyme (3a-HSD) to convert cortisone to cortisol and the Square Wave Voltammetry (SWV) as a preferred method to measure the forward and reverse current of the system. The parameters and equations necessary to estimate the Square Wave Voltammetry (SWV) theoretical response are determined and outlined. The response is modeled and the results are compared to the experimental data. Further, the design of the sensor is analyzed and suggestions are made on how to improve the repeatability of the sensor's response.
The diffusion coefficients for cortisone and cortisol hormone are calculated to be 2.87*10-10 and 2.84*10-10 square meters per second respectively with 10 percent tolerance. The dimensionless peak current (ψ) for the system is approximately 10 percent lower than the one theoretically postulated by Bard et al. [3]. The surface area of the working electrode of the sensor varies with and is directly proportional to the concentration of the analyte. Theoretical current peaks are hypothesized to be within 10 percent tolerance limits (mainly due to the reason that the surface area of the working electrode is itself a variable).
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Museo de la Inmigración en Lima / Lima’s Inmigration MuseumDomínguez Jiménez, Roxana Isabel 08 July 2019 (has links)
La presente tesis “Museo de la Inmigración en Lima” habla sobre la inmigración masiva ocurrida en la década de los 40s en la ciudad. Cultura limeña y provinciana encontradas cuando muchos peruanos provenientes de distintas partes tuvieron que migrar a la capital, dejando sus tierras atrás.
El museo tiene como principal motivación revalidar el esfuerzo, el aporte cultural, y el papel significativo que tuvieron los inmigrantes andinos en la formación de la ciudad de Lima. La propuesta arquitectónica inserta al proyecto en una zona histórica para la inmigración de la época, rodeado de hitos actualmente importantes en la ciudad.
Siendo el primer museo en tratar sobre la inmigración andina en el Perú, se pretende explicar el fenómeno migratorio y a su vez albergar registros históricos, para de esta manera recuperar parte de la historia de la ciudad, para esta generación y las generaciones futuras. Teniendo como finalidad crear una identificación y conocimiento sobre la multiculturalidad que convive en Lima. Además, que el proyecto funcione como espacio público integrador en el cual la población pueda participar de forma activa. / The present thesis "Museo de la Inmigración en Lima" talks about the massive immigration that took place in the decade of the 40s in the city. Lima and provincial culture found when many Peruvians from different parts of the country had to move to the capital, leaving their lands behind.
This museum is inspired by the migrant effort, their cultural contribution, and the significant role that they had in forming the new city of Lima. The architectural proposal inserts the project into a historic area for the immigration, surrounded by many important landmarks in the city.
Being the first museum to deal with Andean immigration in Peru, it is intended to explain the migratory phenomenon and in turn keep historical records, to recover part of the history of the city, for this generation and future ones. With the purpose of creating an identification and knowledge about multiculturalism that lives in Lima. In addition, that the project works as an integrating public space in which the visitors can participate actively. / Tesis
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1989 Chinese Pro-democracy Movement and U.S. News MediaSun, Jie 31 July 1992 (has links)
This thesis explores three aspects of the relationship between U.S. news media and the Chinese pro-democracy movement in 1989. These three aspects are: How much attention did u.s. newspapers give to the Chinese pro-democracy movement in 1989? How did u.s. newspapers portray the power struggle in the Chinese government during the time when the Chinese pro-democracy movement took place? Has there been any change in the image of China during and after the Chinese pro-democracy movement in 1989? Research data are drawn from the following three U.S. newspapers: The New York Times, Washington Post, and Los Angeles Times. Content analysis is adopted as the research method in this study. This research method is carried out in three parts targeting the three research questions mentioned above. The first part shows the total front-page space and number of news stories in the three u.s. newspapers. The front-page space and number of news stories in each newspaper is utilized to measure the degree of attention that each newspaper gave to the Chinese pro-democracy movement in 1989. The second part illustrates the power struggle in the Chinese government. Top Chinese officials are presented as either losing or gaining power based on the treatment they received from the three u.s. newspapers. The third part demonstrates the change in the image of China during and after the Chinese pro-democracy movement in 1989. Both positive and negative changes in the image of China are determined by the use of ideological and non-ideological symbolic representations of China in news stories. Research findings on the first research question show that both front-page space and number of news stories related to events in China increased dramatically in all three u.s. newspapers. Research findings on the power struggle in the Chinese government showed that, in general, all three u.s. newspapers viewed the three top Chinese officials as losing power before military troops were used to control the situation in Beijing on June 4, 1989. Finally, research findings showed a negative change in the image of China during and the Chinese pro-democracy movement, especially after the Chinese government regained control of Tiananmen Square by using military force on June 4, 1989. Implications for future research in mass communication are discussed and, finally, the thesis concludes with suggestions for further research in mass media and communication.
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Joint Preprocesser-Based Detectors for One-Way and Two-Way Cooperative Communication NetworksAbuzaid, Abdulrahman I. 05 1900 (has links)
Efficient receiver designs for cooperative communication networks are becoming increasingly important. In previous work, cooperative networks communicated with the use of L relays. As the receiver is constrained, channel shortening and reduced-rank techniques were employed to design the preprocessing matrix that reduces the length of the received vector from L to U. In the first part of the work, a receiver structure is proposed which combines our proposed threshold selection criteria with the joint iterative optimization (JIO) algorithm that is based on the mean square error (MSE). Our receiver assists in determining the optimal U. Furthermore, this receiver provides the freedom to choose U for each frame depending on the tolerable difference allowed for MSE. Our study and simulation results show that by choosing an appropriate threshold, it is possible to gain in terms of complexity savings while having no or minimal effect on the BER performance of the system. Furthermore, the effect of channel estimation on the performance of the cooperative system is investigated. In the second part of the work, a joint preprocessor-based detector for cooperative communication networks is proposed for one-way and two-way relaying. This joint preprocessor-based detector operates on the principles of minimizing the symbol error rate (SER) instead of minimizing MSE. For a realistic assessment, pilot symbols are used to estimate the channel. From our simulations, it can be observed that our proposed detector achieves the same SER performance as that of the maximum likelihood (ML) detector with all participating relays. Additionally, our detector outperforms selection combining (SC), channel shortening (CS) scheme and reduced-rank techniques when using the same U. Finally, our proposed scheme has the lowest computational complexity.
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The Power of Categorical Goodness-Of-Fit StatisticsSteele, Michael C., n/a January 2003 (has links)
The relative power of goodness-of-fit test statistics has long been debated in the literature. Chi-Square type test statistics to determine 'fit' for categorical data are still dominant in the goodness-of-fit arena. Empirical Distribution Function type goodness-of-fit test statistics are known to be relatively more powerful than Chi-Square type test statistics for restricted types of null and alternative distributions. In many practical applications researchers who use a standard Chi-Square type goodness-of-fit test statistic ignore the rank of ordinal classes. This thesis reviews literature in the goodness-of-fit field, with major emphasis on categorical goodness-of-fit tests. The continued use of an asymptotic distribution to approximate the exact distribution of categorical goodness-of-fit test statistics is discouraged. It is unlikely that an asymptotic distribution will produce a more accurate estimation of the exact distribution of a goodness-of-fit test statistic than a Monte Carlo approximation with a large number of simulations. Due to their relatively higher powers for restricted types of null and alternative distributions, several authors recommend the use of Empirical Distribution Function test statistics over nominal goodness-of-fit test statistics such as Pearson's Chi-Square. In-depth power studies confirm the views of other authors that categorical Empirical Distribution Function type test statistics do not have higher power for some common null and alternative distributions. Because of this, it is not sensible to make a conclusive recommendation to always use an Empirical Distribution Function type test statistic instead of a nominal goodness-of-fit test statistic. Traditionally the recommendation to determine 'fit' for multivariate categorical data is to treat categories as nominal, an approach which precludes any gain in power which may accrue from a ranking, should one or more variables be ordinal. The presence of multiple criteria through multivariate data may result in partially ordered categories, some of which have equal ranking. This thesis proposes a modification to the currently available Kolmogorov-Smirnov test statistics for ordinal and nominal categorical data to account for situations of partially ordered categories. The new test statistic, called the Combined Kolmogorov-Smirnov, is relatively more powerful than Pearson's Chi-Square and the nominal Kolmogorov-Smirnov test statistic for some null and alternative distributions. A recommendation is made to use the new test statistic with higher power in situations where some benefit can be achieved by incorporating an Empirical Distribution Function approach, but the data lack a complete natural ordering of categories. The new and established categorical goodness-of-fit test statistics are demonstrated in the analysis of categorical data with brief applications as diverse as familiarity of defence programs, the number of recruits produced by the Merlin bird, a demographic problem, and DNA profiling of genotypes. The results from these applications confirm the recommendations associated with specific goodness-of-fit test statistics throughout this thesis.
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Users and an online catalogue : an evaluation of the OPAC at the Dixson Library, University of New EnglandBarret, Beverley, n/a January 1989 (has links)
This thesis reports on a study undertaken at the Dixson Library, University of New
England. The purpose of the study was to develop an understanding of users of online
public access catalogues (OPACs). The understanding gained from the study will assist
in the development of improvements to the Library's OPAC, and increase user ability to
access information from the OPAC. The study replicated the user questionnaire of the
Online Patron Access Project, sponsored by the Council on Library Resources (CLR) in
1981/83. The questionnaire was modified slightly to suit conditions at the Dixson
Library.
The study addressed nine research questions relating to the users, their reactions,
attitudes, experiences and problems. The user task and their suggestions for
improvement were also addressed. The study formally tested three propositions between
the variables user task, success and attitudes in relation to OPAC users.
The findings show the analysis of the responses for the population as a whole, and,
where relevant, for eight groups of student respondents based on their academic
affiliation. The student population was of particular importance because of the
preponderance of external students at the University of New England. The differences in
the findings between the groups of students were discussed, and where possible,
explained. The three formal propositions were tested by carrying out Chi square tests for
the values of each variable. Nine significant relationships were found.
Comparisons were made between the Dixson Library findings and those of the CLR
study. Recommendations and conclusions were drawn from the study, including areas
for further research.
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Involvement, motivation and setting preferences of participants in the adventure tourism activity of SCUBA divingTschapka, Michael Karl, n/a January 2006 (has links)
Adventure tourism is a growing market sector worldwide including Australia. A range of
research exists that examined participation in adventure tourism activities by consideration
of various aspects such as socio-demographics, motivations, activity/setting preferences
and involvement in the activity to understand the adventure tourist. While studies have
been conducted that included several of these aspects, a holistic investigation of
involvement, motivations and setting preferences together has not been conducted
previously regarding adventure tourism in Australia in general and SCUBA diving in
particular. Furthermore, in Australia, only limited information is available about those who
participate in the adventure activity of SCUBA diving. The aim of this research is to
investigate differences and similarities of involvement, motivations and setting preferences
of SCUBA diving club members in Eastern Australia.
In this study 294 SCUBA diving club members in New South Wales and Queensland were
surveyed by utilisation of a web-based questionnaire in order to identify their involvement
in SCUBA diving, socio-demographic characteristics, participation motives and setting
preferences.
Descriptive analysis was used to investigate the socio-demographic characteristics of
divers, their motivations and setting preferences. Principal component analysis was applied
on involvement variables as well as motivations to investigate the underlying constructs.
Agglomerative and hierarchical cluster analyses were used to derive clusters of divers that
differed in their involvement in SCUBA diving. Exact Pearson chi-square tests were
conducted to test whether there were significant differences concerning sociodemographics
between clusters. In addition, analyses of variance (ANOVAs) were
conducted to determine differences and similarities of motivational components and setting
preferences between clusters.
This study found that SCUBA diving club members are a heterogeneous group regarding
their involvement in SCUBA diving. Five clusters of divers emerged that differed in their
involvement in SCUBA diving. While differences in socio-demographics across the
different involvement clusters were revealed, they proved to be less valuable for
interpretation purposes. Regarding divers� setting preferences, similar structures were
observed across all clusters regardless of differences in involvement. Motivations showed a
complex structure across the clusters in regard to divers� involvement in SCUBA diving.
Based on the studies findings, recommendations for future research were suggested. These
emphasised the need for a holistic examination of motivations and setting preferences of
adventure tourists based on the concept of involvement, which would be important for
theory development and segmentation of tourists. The same holistic approach would also
be valuable for examining other types of tourists such as events tourists and heritage
tourists to better understand tourist behaviour.
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Analysis of Some Linear and Nonlinear Time Series ModelsAinkaran, Ponnuthurai January 2004 (has links)
Abstract This thesis considers some linear and nonlinear time series models. In the linear case, the analysis of a large number of short time series generated by a first order autoregressive type model is considered. The conditional and exact maximum likelihood procedures are developed to estimate parameters. Simulation results are presented and compare the bias and the mean square errors of the parameter estimates. In Chapter 3, five important nonlinear models are considered and their time series properties are discussed. The estimating function approach for nonlinear models is developed in detail in Chapter 4 and examples are added to illustrate the theory. A simulation study is carried out to examine the finite sample behavior of these proposed estimates based on the estimating functions.
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Linear Models of Nonlinear SystemsEnqvist, Martin January 2005 (has links)
<p>Linear time-invariant approximations of nonlinear systems are used in many applications and can be obtained in several ways. For example, using system identification and the prediction-error method, it is always possible to estimate a linear model without considering the fact that the input and output measurements in many cases come from a nonlinear system. One of the main objectives of this thesis is to explain some properties of such approximate models.</p><p>More specifically, linear time-invariant models that are optimal approximations in the sense that they minimize a mean-square error criterion are considered. Linear models, both with and without a noise description, are studied. Some interesting, but in applications usually undesirable, properties of such optimal models are pointed out. It is shown that the optimal linear model can be very sensitive to small nonlinearities. Hence, the linear approximation of an almost linear system can be useless for some applications, such as robust control design. Furthermore, it is shown that standard validation methods, designed for identification of linear systems, cannot always be used to validate an optimal linear approximation of a nonlinear system.</p><p>In order to improve the models, conditions on the input signal that imply various useful properties of the linear approximations are given. It is shown, for instance, that minimum phase filtered white noise in many senses is a good choice of input signal. Furthermore, the class of separable signals is studied in detail. This class contains Gaussian signals and it turns out that these signals are especially useful for obtaining approximations of generalized Wiener-Hammerstein systems. It is also shown that some random multisine signals are separable. In addition, some theoretical results about almost linear systems are presented.</p><p>In standard methods for robust control design, the size of the model error is assumed to be known for all input signals. However, in many situations, this is not a realistic assumption when a nonlinear system is approximated with a linear model. In this thesis, it is described how robust control design of some nonlinear systems can be performed based on a discrete-time linear model and a model error model valid only for bounded inputs.</p><p>It is sometimes undesirable that small nonlinearities in a system influence the linear approximation of it. In some cases, this influence can be reduced if a small nonlinearity is included in the model. In this thesis, an identification method with this option is presented for nonlinear autoregressive systems with external inputs. Using this method, models with a parametric linear part and a nonparametric Lipschitz continuous nonlinear part can be estimated by solving a convex optimization problem.</p> / <p>Linjära tidsinvarianta approximationer av olinjära system har många användningsområden och kan tas fram på flera sätt. Om man har mätningar av in- och utsignalerna från ett olinjärt system kan man till exempel använda systemidentifiering och prediktionsfelsmetoden för att skatta en linjär modell utan att ta hänsyn till att systemet egentligen är olinjärt. Ett av huvudmålen med den här avhandlingen är att beskriva egenskaper för sådana approximativa modeller.</p><p>Framförallt studeras linjära tidsinvarianta modeller som är optimala approximationer i meningen att de minimerar ett kriterium baserat på medelkvadratfelet. Brusmodeller kan inkluderas i dessa modelltyper och både fallet med och utan brusmodell studeras här. Modeller som är optimala i medelkvadratfelsmening visar sig kunna uppvisa ett antal intressanta, men ibland oönskade, egenskaper. Bland annat visas det att en optimal linjär modell kan vara mycket känslig för små olinjäriteter. Denna känslighet är inte önskvärd i de flesta tillämpningar och innebär att en linjär approximation av ett nästan linjärt system kan vara oanvändbar för till exempel robust reglerdesign. Vidare visas det att en del valideringsmetoder som är framtagna för linjära system inte alltid kan användas för validering av linjära approximationer av olinjära system.</p><p>Man kan dock göra de optimala linjära modellerna mer användbara genom att välja lämpliga insignaler. Bland annat visas det att minfasfiltrerat vitt brus i många avseenden är ett bra val av insignal. Klassen av separabla signaler detaljstuderas också. Denna klass innehåller till exempel alla gaussiska signaler och just dessa signaler visar sig vara speciellt användbara för att ta fram approximationer av generaliserade wiener-hammerstein-system. Dessutom visas det att en viss typ av slumpmässiga multisinussignaler är separabel. Några teoretiska resultat om nästan linjära system presenteras också.</p><p>De flesta metoder för robust reglerdesign kan bara användas om storleken på modellfelet är känd för alla tänkbara insignaler. Detta är emellertid ofta inte realistiskt när ett olinjärt system approximeras med en linjär modell. I denna avhandling beskrivs därför ett alternativt sätt att göra en robust reglerdesign baserat på en tidsdiskret modell och en modellfelsmodell som bara är giltig för begränsade insignaler.</p><p>Ibland skulle det vara önskvärt om en linjär modell av ett system inte påverkades av förekomsten av små olinjäriteter i systemet. Denna oönskade påverkan kan i vissa fall reduceras om en liten olinjär term tas med i modellen. En identifieringsmetod för olinjära autoregressiva system med externa insignaler där denna möjlighet finns beskrivs här. Med hjälp av denna metod kan modeller som består av en parametrisk linjär del och en ickeparametrisk lipschitzkontinuerlig olinjär del skattas genom att man löser ett konvext optimeringsproblem.</p>
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Hedmans Kvadratrotsalgoritm / Hedman´s square root algorithmHedman, Anders January 2001 (has links)
<p>I detta 10-poängsarbete går jag igenom hur min egenhändigt producerade kvadratrotsalgoritm fungerar praktiskt och teoretiskt. Med denna algoritm kan man för hand räkna ut kvadratrötter som innehåller 50-60 värdesiffror. Med de tidigare kända algoritmerna för kvadratrötter kan man räkna ut 5-6 värdesiffror. </p><p>Min algoritm fungerar inte på samma sätt som de tidigare använda kvadratrotsalgoritmerna men den är lika korrekt. Stor tyngdvikt i arbetet har därför lagts på att visa på att det finns flera olika korrekta algoritmer för våra vanliga räknesätt. </p><p>Arbetet innehåller också en kort skildring av den pågående debatten huruvida algoritmräkning i grundskolan hämmar elevernas matematiska tänkande eller inte.</p>
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