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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Facilitating Conceptual Learning in Quantitative Chemistry

Johnson, Sarah R 01 May 2016 (has links)
Traditional chemistry laboratory courses have a manual consisting of “step-by-step” experiments; instructions are given to complete experiments, requiring minimal information/concepts processing to be successful. This experience leaves students unprepared for the real-world, where critical thinking skills are needed to conduct research. This study focused on building analytical techniques, conceptual knowledge, and critical thinking skills used to solve research problems. A new quantitative chemistry laboratory manual was developed to transition students from traditional to inquiry-based experiments, requiring analytical method development. Data showed students having less difficulty using the new manual (0.8281 average difficulty) on method development exam questions and experiments, compared to the traditional manual (0.600 average difficulty). T-test showed significant difference between item difficulty, p = 0.029. Using null hypotheses, the new laboratory manual led to an increase in students’ conceptual knowledge and research skills. They were able to use their knowledge and skills to successfully solve real-world related problems.
182

A Comparison of Modern Longitudinal Change Models with an Examination of Alternative Error Covariance Structures

Maerten-Rivera, Jaime 22 April 2010 (has links)
The purpose of this research was to compare results from two approaches to measuring change over time. The multilevel model (MLM) and latent growth model (LGM) were imposed and the parameter estimates were compared, along with model fit. The study came out of education and used data collected from 191 teachers as part of a professional development intervention in science, which took place over four years. There were missing data as a result of teacher attrition. Teachers reported use of reform-oriented practices (ROP) was used as the outcome, and teacher-level variables were examined for their impact on initial ROP and change in ROP from baseline to one year after the intervention. Change in ROP was examined using a piecewise change model where two linear slopes were modeled. The first slope estimated the change from baseline to T1, or the initial change after the intervention while the second slope estimated the change from T1 to T3, or the secondary change. Parameter estimates obtained from MLM and LGM for a model using the error covariance structure commonly assumed in MLM (i.e., random slopes, homogeneous level-1 variance) were nearly identical. Models with various alternative covariance structures (commonly associated with the LGM framework) were examined, and results were nearly identical. Most of the model fit information was in agreement regarding the best fitting model being the model that assumed the typical MLM error covariance structure with the exception of the standardized root mean square residual (SRMR) fit index. The results from the models demonstrated that ROP increased after participating in the first year of the intervention and this level was sustained, though did not increase significantly in subsequent years. There was more variation in ROP at baseline. This information tells us that the intervention was successful in that after participating in the intervention the teachers' used ROP more frequently. The success of the intervention did not depend on any of the predictors that we assessed, and, as a group, the teachers became more similar in their use of reform-oriented practices over time.
183

Separation of Pharmaceuticals by Capillary Electrophoresis using Partial Filling and Multiple-injections

Lodén, Henrik January 2008 (has links)
Different multiple-injection methodologies and the partial filling technique (PFT) have been utilized for separation of pharmaceuticals by capillary elec-trophoresis. In multiple-injection capillary zone electrophoresis (MICZE), the samples and all standards, used for construction of the calibration curve, are analyzed within a single run. Four different modes of MICZE have been described by means of equations, which were experimentally verified. The developed equations facilitate the transfer from conventional single-injection CZE to one or more of these MICZE-modes, depending on the selectivity between the analyte and the injection marker. The applicability of two of these modes was then demonstrated by quantification of buserelin and salbutamol, re-spectively in commercially available pharmaceutical products. The content of buserelin in an injection solution was determined to 0.94 mg/ml, which only deviated slightly from the declared concentration (1 mg/ml). An alter-native mode of MICZE, offering a higher number of sequential sample injec-tions, was then utilized for single-run determination of salbutamol in 15 tab-lets, with a labelled content of 8 mg. The average content of the tablets was determined to 7.8 mg, with an intra-tablet variation of 3 % or less. Moreover, UV- and mass-spectrometric detection of enantiomeric amines, resolved by non-aqueous capillary electrophoresis (NACE), was demon-strated. Separation of enantiomeric amines was achieved using the chiral selector (-)-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid, (-)-DIKGA. Introduction of the non-volatile (-)-DIKGA into the mass-spectrometer was avoided by using the PFT, where the capillary is only partially filled with electrolyte containing the chiral selector.
184

Quantitative modeling and analysis of service-oriented real-time systems using interval probabilistic timed automata

Krause, Christian, Giese, Holger January 2012 (has links)
One of the key challenges in service-oriented systems engineering is the prediction and assurance of non-functional properties, such as the reliability and the availability of composite interorganizational services. Such systems are often characterized by a variety of inherent uncertainties, which must be addressed in the modeling and the analysis approach. The different relevant types of uncertainties can be categorized into (1) epistemic uncertainties due to incomplete knowledge and (2) randomization as explicitly used in protocols or as a result of physical processes. In this report, we study a probabilistic timed model which allows us to quantitatively reason about nonfunctional properties for a restricted class of service-oriented real-time systems using formal methods. To properly motivate the choice for the used approach, we devise a requirements catalogue for the modeling and the analysis of probabilistic real-time systems with uncertainties and provide evidence that the uncertainties of type (1) and (2) in the targeted systems have a major impact on the used models and require distinguished analysis approaches. The formal model we use in this report are Interval Probabilistic Timed Automata (IPTA). Based on the outlined requirements, we give evidence that this model provides both enough expressiveness for a realistic and modular specifiation of the targeted class of systems, and suitable formal methods for analyzing properties, such as safety and reliability properties in a quantitative manner. As technical means for the quantitative analysis, we build on probabilistic model checking, specifically on probabilistic time-bounded reachability analysis and computation of expected reachability rewards and costs. To carry out the quantitative analysis using probabilistic model checking, we developed an extension of the Prism tool for modeling and analyzing IPTA. Our extension of Prism introduces a means for modeling probabilistic uncertainty in the form of probability intervals, as required for IPTA. For analyzing IPTA, our Prism extension moreover adds support for probabilistic reachability checking and computation of expected rewards and costs. We discuss the performance of our extended version of Prism and compare the interval-based IPTA approach to models with fixed probabilities. / Eine der wichtigsten Herausforderungen in der Entwicklung von Service-orientierten Systemen ist die Vorhersage und die Zusicherung von nicht-funktionalen Eigenschaften, wie Ausfallsicherheit und Verfügbarkeit von zusammengesetzten, interorganisationellen Diensten. Diese Systeme sind oft charakterisiert durch eine Vielzahl von inhärenten Unsicherheiten, welche sowohl in der Modellierung als auch in der Analyse eine Rolle spielen. Die verschiedenen relevanten Arten von Unsicherheiten können eingeteilt werden in (1) epistemische Unsicherheiten aufgrund von unvollständigem Wissen und (2) Zufall als Mittel in Protokollen oder als Resultat von physikalischen Prozessen. In diesem Bericht wird ein probabilistisches, Zeit-behaftetes Modell untersucht, welches es ermöglicht quantitative Aussagen über nicht-funktionale Eigenschaften von einer eingeschränkten Klasse von Service-orientierten Echtzeitsystemen mittels formaler Methoden zu treffen. Zur Motivation und Einordnung wird ein Anforderungskatalog für probabilistische Echtzeitsysteme mit Unsicherheiten erstellt und gezeigt, dass die Unsicherheiten vom Typ (1) und (2) in den untersuchten Systemen einen Ein uss auf die Wahl der Modellierungs- und der Analysemethode haben. Als formales Modell werden Interval Probabilistic Timed Automata (IPTA) benutzt. Basierend auf den erarbeiteten Anforderungen wird gezeigt, dass dieses Modell sowohl ausreichende Ausdrucksstärke für eine realistische und modulare Spezifikation als auch geeignete formale Methoden zur Bestimmung von quantitativen Sicherheits- und Zuverlässlichkeitseigenschaften bietet. Als technisches Mittel für die quantitative Analyse wird probabilistisches Model Checking, speziell probabilistische Zeit-beschränkte Erreichbarkeitsanalyse und Bestimmung von Erwartungswerten für Kosten und Vergütungen eingesetzt. Um die quantitative Analyse mittels probabilistischem Model Checking durchzuführen, wird eine Erweiterung des Prism-Werkzeugs zur Modellierung und Analyse von IPTA eingeführt. Die präsentierte Erweiterung von Prism ermöglicht die Modellierung von probabilistischen Unsicherheiten mittelsWahrscheinlichkeitsintervallen, wie sie für IPTA benötigt werden. Zur Verifikation wird probabilistische Erreichbarkeitsanalyse und die Berechnung von Erwartungswerten durch das Werkzeug unterstützt. Es wird die Performanz der Prism-Erweiterung untersucht und der Intervall-basierte IPTA-Ansatz mit Modellen mit festen Wahrscheinlichkeitswerten verglichen.
185

Cross-cultural study on decision making of German and Indian university students

Tipandjan, Arun 04 June 2010 (has links) (PDF)
The dissertation consists of an introduction and three empirical articles. The introduction gives the theoretical background, integrates the three articles, and elaborates on future research questions. The first article investigates the important decision in the lives of German and Indian university students to identify the important areas of decision making. The second article examines the structure of real life decision making and reveals the underlying factors of five major decision areas. The third article investigates the similarities and differences on decision making between German and Indian students using prior qualitative findings in a large quantitative survey.
186

Unicellular Parasite Motility: A Quantitative Perspective / Einzelligen Parasiten Motilität: Quantitativer Sicht

Uppaluri, Sravanti 27 June 2011 (has links)
No description available.
187

An analytical framework for monitoring and optimizing bank branch network efficiency / E.H. Smith

Smith, Eugene Herbie January 2009 (has links)
Financial institutions make use of a variety of delivery channels for servicing their customers. The primary channel utilised as a means of acquiring new customers and increasing market share is through the retail branch network. The 1990s saw the Internet explosion and with it a threat to branches. The relatively low cost associated with virtual delivery channels made it inevitable for financial institutions to direct their focus towards such new and more cost efficient technologies. By the beginning of the 21st century -and with increasing limitations identified in alternative virtual delivery channels, the financial industry returned to a more balanced view which may be seen as the revival of branch networks. The main purpose of this study is to provide a roadmap for financial institutions in managing their branch network. A three step methodology, representative of data mining and management science techniques, will be used to explain relative branch efficiency. The methodology consists of clustering analysis (CA), data envelopment analysis (DEA) and decision tree induction (DTI). CA is applied to data internal to the financial institution for increasing' the discriminatory power of DEA. DEA is used to calculate the relevant operating efficiencies of branches deemed homogeneous during CA. Finally, DTI is used to interpret the DEA results and additional data describing the market environment the branch operates in, as well as inquiring into the nature of the relative efficiency of the branch. / Thesis (M.Com. (Computer Science))--North-West University, Potchefstroom Campus, 2010.
188

An analytical framework for monitoring and optimizing bank branch network efficiency / E.H. Smith

Smith, Eugene Herbie January 2009 (has links)
Financial institutions make use of a variety of delivery channels for servicing their customers. The primary channel utilised as a means of acquiring new customers and increasing market share is through the retail branch network. The 1990s saw the Internet explosion and with it a threat to branches. The relatively low cost associated with virtual delivery channels made it inevitable for financial institutions to direct their focus towards such new and more cost efficient technologies. By the beginning of the 21st century -and with increasing limitations identified in alternative virtual delivery channels, the financial industry returned to a more balanced view which may be seen as the revival of branch networks. The main purpose of this study is to provide a roadmap for financial institutions in managing their branch network. A three step methodology, representative of data mining and management science techniques, will be used to explain relative branch efficiency. The methodology consists of clustering analysis (CA), data envelopment analysis (DEA) and decision tree induction (DTI). CA is applied to data internal to the financial institution for increasing' the discriminatory power of DEA. DEA is used to calculate the relevant operating efficiencies of branches deemed homogeneous during CA. Finally, DTI is used to interpret the DEA results and additional data describing the market environment the branch operates in, as well as inquiring into the nature of the relative efficiency of the branch. / Thesis (M.Com. (Computer Science))--North-West University, Potchefstroom Campus, 2010.
189

Modélisation, analyse et conception de protocoles MAC multi-canaux dans les réseaux sans fil / Modeling, analysis and design of multi-channel MAC protocols in wireless networks

El Fatni, Abdelaziz 03 June 2013 (has links)
L’utilisation des communications multi-canaux au niveau des protocoles MAC (MAC multi-canaux) dans les réseaux sans fil peut améliorer significativement le débit du réseau par rapport aux protocoles MAC mono-canal en permettant à plusieurs transmissions concurrentes d’avoir lieu simultanément sans interférence sur différents canaux non recouverts. Cependant, l’environnement multicanaux ajoute une nouvelle dimension aux protocoles MAC qui nécessite un nouveau mécanisme appelé "le mécanisme d’allocation des canaux" pour coordonner l’utilisation des canaux. Le rôle de ce mécanisme est de permettre aux nœuds de s’accorder sur le canal qui doit être utilisé et à quel moment pour la transmission de données dans un contexte distribué. L’absence de ce mécanisme ou une mauvaise coordination de l’utilisation des canaux peut produire l’effet inverse de celui recherché. Ainsi, l’efficacité d’un protocole MAC multi-canaux dépend strictement de l’efficacité du mécanisme d’allocation des canaux, qui par ailleurs, doit offrir les garanties nécessaires au fonctionnement de la communication multi-canaux. Dans cette thèse, nous nous intéressons à la modélisation, l’analyse et la conception de nouveaux protocoles MAC multi-canaux dans les réseaux sans fil. Dans un premier temps, nous nous focalisons sur la spécification formelle et la vérification des propriétés fondamentales inhérentes aux activités de l’allocation des canaux et son impact sur le transfert de données des principales approches MAC multi-canaux proposées dans la littérature. Dans un second temps, nous visons à proposer, modéliser et à analyser formellement deux nouveaux protocoles MAC multicanaux résultants de l’analyse qualitative réalisée. Enfin, une étude quantitative et comparative est menée afin d’analyser les performances des protocoles proposés en terme de débit et d’impact du temps de commutation entre les canaux. / The use of multi-channel communications in MAC protocols (multi-channel MAC) for wireless networks can significantly improve the network throughput compared with single channel MAC protocols since concurrent transmissions can take place simultaneously on distinct non-overlapping channels without interfering. However, due to the multi-channel environment, a novel issue must be addressed in MAC protocols, which is called "the channel assignment mechanism" in order to coordinate the channels access. The role of this mechanism is to enable nodes to agree on which channel should be used and when for data transmission in a distributed way. The absence of this mechanism or a bad coordination of the channel usage can incur the opposite effect to that intended. Thus, the efficiency of a multi-channel MAC protocol depends strictly on the efficiency of the channel assignment mechanism, which also must provide the guarantees necessary to the good behavior of the multi-channel communications. In this thesis, we focus on the modeling, analysis, and design of new multi-channel MAC protocols in wireless networks. Firstly, we focus on the formal specification and verification of fundamental properties inherent to the activities of the channel assignment and its impact on the data transfer for the main multi-channel MAC approaches proposed in the literature. Secondly, we aim to propose, model and analyze formally two new multichannel MAC protocols, resulting from the qualitative analysis conducted. Finally, a quantitative and comparative study is conducted to analyze the performance of the proposed protocols in terms of the throughput and the impact of the switching time between channels.
190

Alimentação do lactente com fissura labiopalatina no primeiro ano de vida

Luiz, Aline Godoi January 2017 (has links)
Orientador: Maria Antonieta de Barros Leite Carvalhaes / Resumo: Objective: To analyze feeding history and maternal experience with breastfeeding infants with cleft lip and palate. Method: descriptive, cross - sectional, double - approach study: quantitative and qualitative, performed at the outpatient clinic of a reference hospital. Data were collected through structured interviews with 150 mothers; 6 mothers participated in the qualitative study. Univariate and multiple logistic regression analyzes were used, adopting as criterion for inclusion in the multiple model p≤0.20. To consider a factor as associated to the outcome, p was considered critical <0.05, in the multiple analysis. These analyzes were performed in the SPSS program. For the qualitative approach the sample was selected for convenience. The statements of the mothers were transcribed in their entirety and analyzed according to the theoretical framework of content analysis according to the steps proposed by Graneheim and Lundman. After analyzing all the qualitative interviews, a framework was constructed with the themes found from the testimonies, being categorized in themes and sub-themes. Results: Less than half of the mothers knew of the prenatal diagnosis and this factor was associated with exclusive breastfeeding in the first week of life, the physician was responsible for the prenatal guidelines. The prevalent type of fissure was unilateral incisive transforamen and on nutritional status, eutrophy prevailed. The strengths, difficulties and challenges faced by the birth ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

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