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1
Freney, Peter J., and n/a. "A tale of two schools : two organizational patterns for catering for the gifted." University of Canberra. Education, 1990. http://erl.canberra.edu.au./public/adt-AUC20060710.143917.
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During the past decade, an increase in activity associated
with the education of the gifted has been evident. This
study provides a social and evaluative framework from
which to view two organizational means of making
educational provision for gifted students. In-class
provision in one school is compared statistically and
descriptively with a partial withdrawal system in another.
The Stake evaluation model was used to provide a focus and
classification system for the collection and processing of
naturalistic data. Group tests of ability, attainment
and attitudes were administered in order to obtain some
more objective data.
Evolutionary changes in the schools during the twelve
month period make for difficulties in comparison; the
reasons for the changes occuring highlight the
difficulties which classroom teachers have in
understanding and coming to grips with teaching gifted
students. Any advantage in terms of student outcomes was
weighted towards the school with in-class provision. The
writer postulates that this was due to the collective
responsibility, or ownership of the program, assumed by
the teachers in this school, as opposed to the situation
in the other school, where only one teacher, the
withdrawal teacher, was prepared to assume this
responsibility. This study will provide valuable insight
for any professionals who wish to undertake similar
programs.
2
Lundström, Johanna. "Professional development for inquiry-based science education in a low stake high support environment : The French ASTEP-program." Thesis, Stockholms universitet, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-146203.
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This work examines the learning outcomes of a French professional development program for science education in primary school, ASTEP. The program is based on a partnership between a primary school teacher on one hand and a subject expert on the other. Its uniqueness lies in the fact that the subject expert is a young university student who is challenged to be assessed on his/her learning for academic credits. Compared to most other professional development programs, ASTEP displays an alternative knowledge hierarchy, it is neither top down nor bottom up, but rather a form of knowledge exchange. Data on students´ and teachers´ reflections on the collaboration were analyzed through a grounded theory approach and subsequently organized within the interconnected model of teacher professional growth (IMTPG). Although the analyses indicated significant changes in the practice of the teachers, the learners who individually seem to benefit the most were the university students. The ASTEP program appears to provide a low stake high support scaffold for the students to refine their values and beliefs about a professional life and develop a professional identity.
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Titman, Andrew Charles. "Model diagnostics in multi-state models of biological systems." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612189.
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li, yiwen. "Predicting Hearing Loss Using Auditory Steady-State Responses." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/84.
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Auditory Steady-State Response (ASSR) is a promising tool for detecting hearing loss. In this project, we analyzed hearing threshold data obtained from two ASSR methods and a gold standard, pure tone audiometry, applied to both normal and hearing-impaired subjects. We constructed a repeated measures linear model to identify factors that show significant differences in the mean response. The analysis shows that there are significant differences due to hearing status (normal or impaired) and ASSR method, and that there is a significant interaction between hearing status and test signal frequency. The second task of this project was to predict the PTA threshold (gold standard) from the ASSR-A and ASSR-B thresholds separately at each frequency, in order to measure how accurate the ASSR measurements are and to obtain a ¡°correction function¡± to correct the bias in the ASSR measurements. We used two approaches. In the first, we modeled the relation of the PTA responses to the ASSR values for the two hearing status groups as a mixture model and tried two prediction methods. The mixture modeling was successful, but the predictions gave disappointing results. A second approach, using logistic regression to predict group membership based on ASSR value and then using those predictions to obtain a predictor of the PTA value, gave successful results.
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Ehlers, Ricardo Sandes. "Bayesian model discrimination for time series and state space models." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/843599/.
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In this thesis, a Bayesian approach is adopted to handle parameter estimation and model uncertainty in autoregressive moving average (ARMA) time series models and dynamic linear models (DLM). Bayesian model uncertainty is handled in a parametric fashion through the use of posterior model probabilities computed via Markov chain Monte Carlo (MCMC) simulation techniques. Attention is focused on reversible jump Markov chain Monte Carlo (RJMCMC) samplers, which can move between models of different dimensions, to address the problem of model order uncertainty and strategies for proposing efficient sampling schemes in autoregressive moving average time series models and dynamic linear models are developed. The general problem of assessing convergence of the sampler in a dimension-changing context is addressed by computing estimates of the probabilities of moving to higher and lower dimensional spaces. Graphical and numerical techniques are used to compare different updating schemes. The methodology is illustrated by applying it to both simulated and real data sets and the results for the Bayesian model selection and parameter estimation procedures are compared with the classical model selection criteria and maximum likelihood estimation.
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Uren, Kenneth Richard. "State space model extraction of thermohydraulic systems / Kenneth R. Uren." Thesis, North-West University, 2009. http://hdl.handle.net/10394/3838.
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Many hours are spent by systemand control engineers deriving reduced order dynamicmodels
portraying the dominant systemdynamics of thermohydraulic systems. A need therefore exists
to develop a method that will automate the model derivation process. The model format
preferred for control system design and analysis during preliminary system design is the state
space format. The aim of this study is therefore to develop an automated and generic state
space model extraction method that can be applied to thermohydraulic systems.
Well developed system identification methods exist for obtaining state space models from
input-output data, but these models are not transparent, meaning the parameters do not
have any physical meaning. For example one cannot identify system parameters such
as heat or mass transfer coefficients. Another approach is needed to derive state space
models automatically. Many commercial thermohydraulic simulation codes follow a network
approach towards the representation of thermohydraulic systems. This approach is probably
one of the most advanced approaches in terms of technical development. It would therefore be
useful to develop a state space extraction algorithm that would be able to derive reduced order
state space models from network representations of thermohydraulic systems. In this regard a
network approach is followed in the development of the state space extraction algorithm. The
advantage of using a network-based extraction method is that the extracted state space model
is transparent and the algorithm can be embedded in existing simulation software that follow
a network approach.
In this study an existing state space extraction algorithm, used for electrical network analysis, is
modified and applied in a new way to extract state space models of thermohydraulic systems.
A thermohydraulic system is partitioned into its respective physical domains which, unlike
electrical systems, have multiple variables. Network representations are derived for each
domain. The state space algorithm is applied to these network representations to extract
symbolic state spacemodels. The symbolic parametersmay then be substitutedwith numerical
values. The state space extraction algorithm is applied to small scale thermohydraulic systems
such as a U-tube and a heat exchanger, but also to a larger, more complex system such
as the Pebble Bed Modular Reactor Power Conversion Unit (PBMR PCU). It is also shown
that the algorithm can extract linear, nonlinear, time-varying and time-invariant state space
models. The extracted state space models are validated by solving the state space models
and comparing the solutions with Flownex results. Flownex is an advanced and extensively
validated thermo-fluid simulation code. The state space models compared well with Flownex
results.
The usefulness of the state space model extraction algorithm in model-based control system
design is illustrated by extracting a linear time-invariant state space model of the PBMR PCU.
This model is embedded in an optimal model-based control scheme called Model-Predictive
Control (MPC). The controller is compared with standard optimised control schemes such as
PID and Fuzzy PID control. The MPC controller shows superior performance compared to
these control schemes.
This study succeeded in developing an automated state space model extraction method that
can be applied to thermohydraulic networks. Hours spent on writing down equations from
first principles to derive reduced order models for control purposes can now be replaced
with a click of a button. The need for an automated state space model extraction method for
thermohydraulic systems has therefore been resolvedThesis (Ph.D. (Computer and Electronical Engineering)--North-West University, Potchefstroom Campus, 2009.
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Alsaeedi, Abdullah. "Improving software model inference by combining state merging and Markov models." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/13645/.
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Labelled-transition systems (LTS) are widely used by developers and testers to model software systems in terms of their sequential behaviour. They provide an overview of the behaviour of the system and their reaction to different inputs. LTS models are the foundation for various automated verification techniques such as model-checking and model-based testing. These techniques require up-to-date models to be meaningful. Unfortunately, software models are rare in practice. Due to the effort and time required to build these models manually, a software engineer would want to infer them automatically from traces (sequences of events or function calls). Many techniques have focused on inferring LTS models from given traces of system execution, where these traces are produced by running a system on a series of tests. State-merging is the foundation of some of the most successful LTS inference techniques to construct LTS models. Passive inference approaches such as k-tail and Evidence-Driven State Merging (EDSM) can infer LTS models from these traces. Moreover, the best-performing methods of inferring LTS models rely on the availability of negatives, i.e. traces that are not permitted from specific states and such information is not usually available. The long-standing challenge for such inference approaches is constructing models well from very few traces and without negatives. Active inference techniques such as Query-driven State Merging (QSM) can learn LTSs from traces by asking queries as tests to a system being learnt. It may lead to infer inaccurate LTSs since the performance of QSM relies on the availability of traces. The challenge for such inference approaches is inferring LTSs well from very few traces and with fewer queries asked. In this thesis, investigations of the existing techniques are presented to the challenge of inferring LTS models from few positive traces. These techniques fail to find correct LTS models in cases of insufficient training data. This thesis focuses on finding better solutions to this problem by using evidence obtained from the Markov models to bias the EDSM learner towards merging states that are more likely to correspond to the same state in a model. Markov models are used to capture the dependencies between event sequences in the collected traces. Those dependencies rely on whether elements of event permitted or prohibited to follow short sequences appear in the traces. This thesis proposed EDSM-Markov a passive inference technique that aimed to improve the existing ones in the absence of negative traces and to prevent the over-generalization problem. In this thesis, improvements obtained by the proposed learners are demonstrated by a series of experiments using randomly-generated labelled-transition systems and case studies. The results obtained from the conducted experiments showed that EDSM-Markov can infer better LTSs compared to other techniques. This thesis also proposes modifications to the QSM learner to improve the accuracy of the inferred LTSs. This results in a new learner, which is named ModifiedQSM. This includes considering more tests to the system being inferred in order to avoid the over-generalization problem. It includes investigations of using Markov models to reduce the number of queries consumed by the ModifiedQSM learner. Hence, this thesis introduces a new LTS inference technique, which is called MarkovQSM. Moreover, enhancements of LTSs inferred by ModifiedQSM and MarkovQSM learners are demonstrated by a series of experiments. The results from the experiments demonstrate that ModifiedQSM can infer better LTSs compared to other techniques. Moreover, MarkovQSM has proven to significantly reduce the number of membership queries consumed compared to ModifiedQSM with a very small loss of accuracy.
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Lampka, Kai. "A symbolic approach to the state graph based analysis of high-level Markov reward models." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985513926.
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Frühwirth-Schnatter, Sylvia. "Recursive Residuals and Model Diagnostics for Normal and Non-Normal State Space Models." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 1994. http://epub.wu.ac.at/1540/1/document.pdf.
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Model diagnostics for normal and non-normal state space models is based on recursive residuals which are defined from the one-step ahead predictive distribution. Routine calculation of these residuals is discussed in detail. Various tools of diagnostics are suggested to check e.g. for wrong observation distributions and for autocorrelation. The paper also covers such topics as model diagnostics for discrete time series, model diagnostics for generalized linear models, and model discrimination via Bayes factors. (author's abstract)Series: Forschungsberichte / Institut für Statistik
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Frühwirth-Schnatter, Sylvia. "Fully Bayesian Analysis of Switching Gaussian State Space Models." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2000. http://epub.wu.ac.at/812/1/document.pdf.
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In the present paper we study switching state space models from a Bayesian point of view. For estimation, the model is reformulated as a hierarchical model. We discuss various MCMC methods for Bayesian estimation, among them unconstrained Gibbs sampling, constrained sampling and permutation sampling. We address in detail the problem of unidentifiability, and discuss potential information available from an unidentified model. Furthermore the paper discusses issues in model selection such as selecting the number of states or testing for the presence of Markov switching heterogeneity. The model likelihoods of all possible hypotheses are estimated by using the method of bridge sampling. We conclude the paper with applications to simulated data as well as to modelling the U.S./U.K. real exchange rate. (author's abstract)Series: Forschungsberichte / Institut für Statistik
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Frühwirth-Schnatter, Sylvia. "Bayesian Model Discrimination and Bayes Factors for Normal Linear State Space Models." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 1993. http://epub.wu.ac.at/108/1/document.pdf.
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It is suggested to discriminate between different state space models for a given time series by means of a Bayesian approach which chooses the model that minimizes the expected loss. Practical implementation of this procedures requires a fully Bayesian analysis for both the state vector and the unknown hyperparameters which is carried out by Markov chain Monte Carlo methods. Application to some non-standard situations such as testing hypotheses on the boundary of the parameter space, discriminating non-nested models and discrimination of more than two models is discussed in detail. (author's abstract)Series: Forschungsberichte / Institut für Statistik
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Subramanian, Sankaranarayanan [Verfasser]. "Tube-enhanced Multi-stage Model Predictive Control : Robust State and Output Feedback Control / Sankaranarayanan Subramanian." Düren : Shaker, 2021. http://d-nb.info/1229779698/34.
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CARLOS, MAURO LAWALL EVARISTO. "A STATISTICAL INVESTIGATION ON TIME SERIES MODELS FOR COUNT DATA: GARMA MODEL AND THE STATE SPACE POISSON GAMMA MODEL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10009@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO presente trabalho tem como objetivo principal investigar por meio de simulação Monte Carlo algumas propriedades estatísticas dos modelos GARMA (Generalized Autoregressive Moving Average) para séries temporais de dados de contagem. Os modelos GARMA são uma extensão dos Modelos Lineares Generalizados de McCullagh e Nelder para situações de dados dependentes, caracterizando-se pela adição de um termo extra ao preditor linear, o qual passa a incorporar termos autoregressivos (AR) e de médias móveis (MA). As propriedades estatísticas investigadas foram às condições de estacionariedade dos modelos GARMA e os critérios de identificação da ordem (p,q) dos polinômios AR e MA que definem o modelo. Os resultados encontrados indicam que os critérios AIC BIC e Hannan-Quin utilizados foram razoavelmente eficazes na identificação da ordem dos modelos e que as condições de estacionariedade estabelecidas empiricamente em termo de restrições no espaço paramétrico são bastante complexas exigindo um estudo mais detalhado. Como objetivo secundário testamos os modelo GARMA em séries reais, ajustando os modelos GARMA- Poissson e GARMA-Binomial Negativa ao número de caso de poliomielite nos EUA e ao número de infartos do miocárdio no município do Rio de Janeiro. Os resultados indicam que os modelos foram capazes de explicar, de forma econômica, a variação destas séries.
The main objective of this dissertation is to investigate, using Monte Carlo simulations, some statistical properties of GARMA (Generalized Autoregressive Moving Average ) models for time series of count data. GARMA models are extensions of the Generalized Linear Models to dependent data, in which autoregressive (AR) and/or moving average (MA) terms are incorporated into the linear predictor. The statistical properties targeted in our investigation were the model stationarity conditions and the identification criteria for selection of model orders, the lag structure (p,q) associated with the AR and MA terms. Our results suggest that AIC, BIC and Hann-Quinn criteria worked relatively well in identifying the model order, and that the conditions for stationarity established empirically in terms of parameter space restrictions were not totally conclusive, requiring further investigation. As a secondary objective we tested the model against real data, by fitting both a GARMA-Poisson and a GARMA-Negative Binomial to the series of number of cases of poliomyelitis on the US and the number of heart-attacks in Rio de Janeiro city. The results we found indicate that these models were able to explain, in a parsimonious way, the variation of both series.
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Mavrakakis, Miltiadis C. "State space models : univariate representation of a multivariate model, partial interpolation and periodic convergence." Thesis, London School of Economics and Political Science (University of London), 2008. http://etheses.lse.ac.uk/2341/.
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This thesis examines several issues that arise from the state space representation of a multivariate time series model. Original proofs of the algorithms for obtaining interpolated estimates of the state and observation vectors from the Kalman filter smoother (KFS) output are presented, particularly for the formulae for which rigorous proofs do not appear in the existing literature. The notion of partially interpolated estimates is introduced and algorithms for constructing these estimates are established. An existing method for constructing a univariate representation (UR) of a multivariate model is developed further, and applied to a wider class of state space models. The computational benefits of filtering and smoothing with the UR, rather than the original multivariate model, are discussed. The UR KFS recursions produce useful quantities that cannot be obtained from the original multivariate model. The mathematical properties of these quantities are examined and the process of reconstructing the original multivariate KFS output is demonstrated By reversing the UR process, a time-invariant state space form (SSF) is proposed for models with periodic system matrices. This SSF is used to explore the novel concept of periodic convergence of the KFS. Necessary and sufficient conditions for periodic convergence are asserted and proved. The techniques developed are then applied to the problem of missing- value estimation in long multivariate temperature series, which can arise due to gaps in the historical records. These missing values are a hindrance to the study of weather risk and pricing of weather derivatives, as well as the development of climate-dependent models. The proposed model-based techniques are compared to existing methods in the field, as well as an original ad hoc approach. The relative performance of these methods is assessed by their application to data from weather stations in the state of Texas, for daily maximum temperatures from 1950 to 2001.
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Winter, Kirsten. "Model checking abstract state machines." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963050001.
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Bae, Kyungcho. "Energy consumption forecasting: Econometric model vs state space model." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/187010.
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This study examines the forecasting performance of two major multivariate methodologies: econometric modeling and multivariate state space modeling. The same variables are used in both models to facilitate comparison. They are evaluated by both expost and exante accuracy of U.S. energy consumption forecasts. Econometric models are highly simplified and a model selection procedure is applied to the models. Two different formats of multivariate state space models are examined: economic structure and identity structure. Goodrich's algorithm is employed to estimate the state space models. The state space models in both the econometric structure and the identity structure provided generally good estimates, usually, but not always, these forecasts were more accurate than those by the single econometric models.
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Khan, Muhammad Alam Z. "Transient engine model for calibration using two-stage regression approach." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8456.
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Engine mapping is the process of empirically modelling engine behaviour as a function of adjustable engine parameters, predicting the output of the engine. The aim is to calibrate the electronic engine controller to meet decreasing emission requirements and increasing fuel economy demands. Modern engines have an increasing number of control parameters that are having a dramatic impact on time and e ort required to obtain optimal engine calibrations. These are further complicated due to transient engine operating mode. A new model-based transient calibration method has been built on the application of hierarchical statistical modelling methods, and analysis of repeated experiments for the application of engine mapping. The methodology is based on two-stage regression approach, which organise the engine data for the mapping process in sweeps. The introduction of time-dependent covariates in the hierarchy of the modelling led to the development of a new approach for the problem of transient engine calibration. This new approach for transient engine modelling is analysed using a small designed data set for a throttle body inferred air ow phenomenon. The data collection for the model was performed on a transient engine test bed as a part of this work, with sophisticated software and hardware installed on it. Models and their associated experimental design protocols have been identi ed that permits the models capable of accurately predicting the desired response features over the whole region of operability. Further, during the course of the work, the utility of multi-layer perceptron (MLP) neural network based model for the multi-covariate case has been demonstrated. The MLP neural network performs slightly better than the radial basis function (RBF) model. The basis of this comparison is made on assessing relevant model selection criteria, as well as internal and external validation ts. Finally, the general ability of the model was demonstrated through the implementation of this methodology for use in the calibration process, for populating the electronic engine control module lookup tables.
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naz, saima. "Forecasting daily maximum temperature of Umeå." Thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112404.
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The aim of this study is to get some approach which can help in improving the predictions of daily temperature of Umeå. Weather forecasts are available through various sources nowadays. There are various software and methods available for time series forecasting. Our aim is to investigate the daily maximum temperatures of Umeå, and compare the performance of some methods in forecasting these temperatures. Here we analyse the data of daily maximum temperatures and find the predictions for some local period using methods of autoregressive integrated moving average (ARIMA), exponential smoothing (ETS), and cubic splines. The forecast package in R is used for this purpose and automatic forecasting methods available in the package are applied for modelling with ARIMA, ETS, and cubic splines. The thesis begins with some initial modelling on univariate time series of daily maximum temperatures. The data of daily maximum temperatures of Umeå from 2008 to 2013 are used to compare the methods using various lengths of training period. On the basis of accuracy measures we try to choose the best method. Keeping in mind the fact that there are various factors which can cause the variability in daily temperature, we try to improve the forecasts in the next part of thesis by using multivariate time series forecasting method on the time series of maximum temperatures together with some other variables. Vector auto regressive (VAR) model from the vars package in R is used to analyse the multivariate time series. Results: ARIMA is selected as the best method in comparison with ETS and cubic smoothing splines to forecast one-step-ahead daily maximum temperature of Umeå, with the training period of one year. It is observed that ARIMA also provides better forecasts of daily temperatures for the next two or three days. On the basis of this study, VAR (for multivariate time series) does not help to improve the forecasts significantly. The proposed ARIMA with one year training period is compatible with the forecasts of daily maximum temperature of Umeå obtained from Swedish Meteorological and Hydrological Institute (SMHI).
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Krus, Kristofer. "Wave Model and Watercraft Model for Simulation of Sea State." Thesis, Linköpings universitet, Teoretisk Fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102959.
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The problem of real-time simulation of ocean surface waves, ship movement and the coupling in between is tackled, and a number of different methods are covered and discussed. Among these methods, the finite volume method has been implemented in an attempt to solve the problem, along with the compressible Euler equations, an octree based staggered grid which allows for easy adaptive mesh refinement, the volume of fluid method and a variant of the Hyper-C advection scheme for compressible flows for advection of the phase fraction field. The process of implementing the methods that were chosen proved to be tricky in many ways, as they involve a large number of advanced topics, and the implementation that was implemented in this thesis work suffered from numerous issues. There were for example problems with keeping the interface intact, as well as a harsh restriction on the time step size due to the CFL condition. Improvements required to make the method sustainable for real-time applications are discussed, and a few suggestions on alternative approaches that are already in use for similar purposes are also given and discussed. Furthermore, a method for compensating for gain/loss of mass when solving the incompressible flow equations with an inaccurately solved pressure Poisson equation is presented and discussed. A momentum conservative method for transporting the velocity field on staggered grids without introducing unnecessary smearing is also presented and implemented. A simple, physically based illumination model for sea surfaces is derived, discussed and compared to the Blinn–Phong shading model, although it is never implemented. Finally, a two-dimensional partial differential equation in the spatial domain for simulating water surface waves for mildly varying bottom topography is derived and discussed, although it is deemed to be too slow for real-time purposes and is therefore never implemented.This publication differs from the printed version of the report in the sense that links are blue in this version and black in the printed version.
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Wan, Lijie. "CONTINUOUS TIME MULTI-STATE MODELS FOR INTERVAL CENSORED DATA." UKnowledge, 2016. http://uknowledge.uky.edu/statistics_etds/19.
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Continuous-time multi-state models are widely used in modeling longitudinal data of disease processes with multiple transient states, yet the analysis is complex when subjects are observed periodically, resulting in interval censored data. Recently, most studies focused on modeling the true disease progression as a discrete time stationary Markov chain, and only a few studies have been carried out regarding non-homogenous multi-state models in the presence of interval-censored data. In this dissertation, several likelihood-based methodologies were proposed to deal with interval censored data in multi-state models.
Firstly, a continuous time version of a homogenous Markov multi-state model with backward transitions was proposed to handle uneven follow-up assessments or skipped visits, resulting in the interval censored data. Simulations were used to compare the performance of the proposed model with the traditional discrete time stationary Markov chain under different types of observation schemes. We applied these two methods to the well-known Nun study, a longitudinal study of 672 participants aged ≥ 75 years at baseline and followed longitudinally with up to ten cognitive assessments per participant.
Secondly, we constructed a non-homogenous Markov model for this type of panel data. The baseline intensity was assumed to be Weibull distributed to accommodate the non-homogenous property. The proportional hazards method was used to incorporate risk factors into the transition intensities. Simulation studies showed that the Weibull assumption does not affect the accuracy of the parameter estimates for the risk factors. We applied our model to data from the BRAiNS study, a longitudinal cohort of 531 subjects each cognitively intact at baseline.
Last, we presented a parametric method of fitting semi-Markov models based on Weibull transition intensities with interval censored cognitive data with death as a competing risk. We relaxed the Markov assumption and took interval censoring into account by integrating out all possible unobserved transitions. The proposed model also allowed for incorporating time-dependent covariates. We provided a goodness-of-fit assessment for the proposed model by the means of prevalence counts. To illustrate the methods, we applied our model to the BRAiNS study.
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Yousef, Mohammed A. "Two-Stage SCAD Lasso for Linear Mixed Model Selection." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1558431514460879.
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Tippa, Anthony. "A state space model for inflation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ47802.pdf.
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Seneviratne, Vidura Priyaranjana. "The hidden vector state language model." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613351.
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Kopciuk, Karen. "Modelling Issues in Three-state Progressive Processes." Thesis, University of Waterloo, 2001. http://hdl.handle.net/10012/1114.
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This dissertation focuses on several issues pertaining to three-state progressive stochastic processes. Casting survival data within a three-state framework is an effective way to incorporate intermediate events into an analysis. These events can yield valuable insights into treatment interventions and the natural history of a process, especially when the right censoring is heavy. Exploiting the uni-directional nature of these processes allows for more effective modelling of the types of incomplete data commonly encountered in practice, as well as time-dependent explanatory variables and different time scales. In Chapter 2, we extend the model developed by Frydman (1995) by incorporating explanatory variables and by permitting interval censoring for the time to the terminal event. The resulting model is quite general and combines features of the models proposed by Frydman (1995) and Kim et al. (1993). The decomposition theorem of Gu (1996) is used to show that all of the estimating equations arising from Frydman's log likelihood function are self-consistent. An AIDS data set analyzed by these authors is used to illustrate our regression approach. Estimating the standard errors of our regression model parameters, by adopting a piecewise constant approach for the baseline intensity parameters, is the focus of Chapter 3. We also develop data-driven algorithms which select changepoints for the intervals of support, based on the Akaike and Schwarz Information Criteria. A sensitivity study is conducted to evaluate these algorithms. The AIDS example is considered here once more; standard errors are estimated for several piecewise constant regression models selected by the model criteria. Our results indicate that for both the example and the sensitivity study, the resulting estimated standard errors of certain model parameters can be quite large. Chapter 4 evaluates the goodness-of-link function for the transition intensity between states 2 and 3 in the regression model we introduced in chapter 2. By embedding this hazard function in a one-parameter family of hazard functions, we can assess its dependence on the specific parametric form adopted. In a simulation study, the goodness-of-link parameter is estimated and its impact on the regression parameters is assessed. The logistic specification of the hazard function from state 2 to state 3 is appropriate for the discrete, parametric-based data sets considered, as well as for the AIDS data. We also investigate the uniqueness and consistency of the maximum likelihood estimates based on our regression model for these AIDS data. In Chapter 5 we consider the possible efficiency gains realized in estimating the survivor function when an intermediate auxiliary variable is incorporated into a time-to-event analysis. Both Markov and hybrid time scale frameworks are adopted in the resulting progressive three-state model. We consider three cases for the amount of information available about the auxiliary variable: the observation is completely unknown, known exactly, or known to be within an interval of time. In the Markov framework, our results suggest that observing subjects at just two time points provides as much information about the survivor function as knowing the exact time of the intermediate event. There was generally a greater loss of efficiency in the hybrid time setting. The final chapter identifies some directions for future research.
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Marx, Alton Cadle. "Determining appropriate loss coefficients for use in the nozzle-model of a stage-by-stage turbine model." Master's thesis, Faculty of Engineering and the Built Environment, 2019. https://hdl.handle.net/11427/31619.
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A previously developed turbine modelling methodology, requiring minimal blade passage information, produced a customizable turbine stage component. This stage-by-stage turbine nozzlemodel component was derived from the synthesis of classical turbine theory and classical nozzle theory enabling the component to accurately model a turbine stage. Utilizing Flownex, a thermohydraulic network solver, the turbine stage component can be expanded to accurately model any arrangement and category of turbine. This project focused on incorporating turbine blade passage geometrical information, as it relates to the turbine specific loss coefficients, into the turbine stage component to allow for the development of turbine models capable of predicting turbine performance for various structural changes, anomalies and operating conditions. The development of turbine loss coefficient algorithms as they relate to specific blade geometry data clusters required the investigation of several turbine loss calculation methodologies. A stage-by-stage turbine nozzle-model incorporating turbine loss coefficient algorithms was developed and validated against real turbine test cases obtained from literature. Several turbine models were developed using the loss coefficient governed turbine stage component illustrating its array of capabilities. The incorporation of the turbine loss coefficient algorithms clearly illustrates the correlation between turbine performance deviations and changes in specific blade geometry data clusters.
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Reed, Joseph A. "Minding the Reflexive Stage of the Temporal Need-Threat Model: State and Trait Mindfulness as Moderators of the Immediate Effects of Social Exclusion." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525449500278843.
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Camargos, Jos? Lucas de. "Modelagem do crescimento e produ??o florestal com n?mero vari?vel de parcelas mensuradas." UFVJM, 2017. http://acervo.ufvjm.edu.br/jspui/handle/1/1384.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)
O objetivo deste trabalho foi avaliar a influ?ncia da redu??o de parcelas em algumas medi??es de invent?rio florestal cont?nuo na modelagem do crescimento e produ??o de um povoamento de Eucalyptus sp. O modelo de Clutter foi utilizado na modelagem do crescimento e da produ??o florestal, a partir de dados selecionados de 374 parcelas distribu?das em 172 talh?es. Foram utilizadas tr?s alternativas de modelagem: sem estratifica??o do povoamento, com estratifica??o do povoamento e um conjunto de 30 simula??es. Estas simula??es foram amostras de 40 parcelas aleat?rias cada, sem estratifica??o, com o objetivo de possibilitar uma an?lise geral dos efeitos do fen?meno estudado. Em todas as alternativas, foi realizada a modelagem do crescimento e da produ??o sem considerar redu??es nas medi??es de invent?rio florestal cont?nuo e considerando tr?s situa??es de redu??o. As situa??es consideradas foram medi??es de 25%, 50% e 75% das parcelas do invent?rio florestal cont?nuo nas medi??es dois e quatro, e 100% nas medi??es um, tr?s e cinco. Esta mesma metodologia foi repetida, por?m com a utiliza??o do modelo de regress?o n?o linear Log?stico, acrescido de um fator de corre??o. Ambos os modelos apresentaram boa precis?o para a predi??o e proje??o do volume do povoamento em idades futuras. O modelo Log?stico com fator de corre??o, entretanto, foi mais preciso que o modelo de Clutter. Para ambos os modelos foi constatado que n?o houveram perdas significativas de precis?o acarretadas pelas redu??es no n?mero de parcelas em algumas medi??es do invent?rio florestal cont?nuo. Para a modelagem do crescimento e da produ??o, ? recomendado que estas redu??es sejam criteriosas e que preferencialmente a ?ltima medi??o n?o seja reduzida.
Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017.
This study had as object to evaluate the influence of the reduction of plots at some measurements of continuous forest inventory in the growth and yield modeling of a Eucalyptus sp. forest stand. The Clutter model was used in forest growth and yield modeling, using selected data of 374 distributed plots in 172 forest compartments. It were used three modeling alternatives: without stratification of the forest stand, with stratification of the forest stand and a set of 30 simulations. These simulations were samples of 40 plots each one, without stratification, objectifying a general analysis about the studied phenomenon. To all the alternatives, it was made the forest growth and yield modeling without considering reductions in continuous forest inventory measurements and considering three reduction situations. The considered situations were measurements of 25%, 50% and 75% of the continuous forest inventory plots in the measures two and four, and 100% in the measures one, three and five. This same methodology was repeated, but using the Logistic nonlinear regression model, plus a correction factor. Both models had good precision to predicting and projecting the forest stand volume at future ages. The Logistic model with a correcting factor, however, had best precision than the Clutter model. For both models it was found that there was not significant losses of accuracy caused by reductions in the number of plots at some continuous forest inventory measurements. To forest growth and yield modeling, it is recommended for these reductions to be judicious and preferably the last measurement to not be reduced.
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Aljamaan, Hamoud. "Model-Oriented Tracing Language: Producing Execution Traces from Tracepoints Injected into Code Generated from UML Models." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33419.
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This thesis investigates the building of a textual tracing language that operates at the model level to allow trace specification of textually modeled UML constructs. Current tracing approaches focus on manually injecting tracepoints into targeted systems at the source code level. Such approaches are useful in code-centric development styles where the majority of the code is handwritten. However, in the case of Model Driven Development (MDD), where models are utilized to generate some or all of the code, current tracing technology results in low level trace specification and generation of execution traces that are not aware of or linked to the originating model-level constructs. Dynamic analysis hence becomes harder for a modeler adopting an MDD approach. This field, which we call model-oriented tracing, is currently immature, with little pre-existing research.
In this thesis, we present a textual model-level tracing language, implemented as part of Umple, that overcomes some of the limitations of existing tracing methods. The language facilitates model-level tracing, in a fashion very similar to code tracing. The language, which we call MOTL (Model-Oriented Tracing Language) allows tracing of UML associations, attributes and state machines. Constraints can be imposed to limit the scope of tracing.
As a result of this work, modelers will gain the ability to specify traces of UML constructs at the model level without the need to modify the generated code, and then generate execution traces when the generated system is run. The resulting trace links back to the model constructs. Modelers can choose from among several tracing technologies including basic file or console output, Java logging framework, Log4J and LTTng.
This thesis defines the language syntactically and semantically. Model-Driven Development (MDD) and Test-Driven Development (TDD) were followed to implement the language architecture to ensure high quality code generation. MOTL was used in the development in two of Umple subprojects. An empirical evaluation was conducted to evaluate the language’s usability.
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Steckenrider, John Josiah. "Simultaneous Estimation and Modeling of State-Space Systems Using Multi-Gaussian Belief Fusion." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97583.
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This work describes a framework for simultaneous estimation and modeling (SEAM) of dynamic systems using non-Gaussian belief fusion by first presenting the relevant fundamental formulations, then building upon these formulations incrementally towards a more general and ubiquitous framework. Multi-Gaussian belief fusion (MBF) is introduced as a natural and effective method of fusing non-Gaussian probability distribution functions (PDFs) in arbitrary dimensions efficiently and with no loss of accuracy. Construction of some multi-Gaussian structures for potential use in MBF is addressed. Furthermore, recursive Bayesian estimation (RBE) is developed for linearized systems with uncertainty in model parameters, and a rudimentary motion model correction stage is introduced. A subsequent improvement to motion model correction for arbitrarily non-Gaussian belief is developed, followed by application to observation models. Finally, SEAM is generalized to fully nonlinear and non-Gaussian systems. Several parametric studies were performed on simulated experiments in order to assess the various dependencies of the SEAM framework and validate its effectiveness in both estimation and modeling. The results of these studies show that SEAM is capable of improving estimation when uncertainty is present in motion and observation models as compared to existing methods. Furthermore, uncertainty in model parameters is consistently reduced as these parameters are updated throughout the estimation process. SEAM and its constituents have potential uses in robotics, target tracking and localization, state estimation, and more.Doctor of Philosophy
The simultaneous estimation and modeling (SEAM) framework and its constituents described in this dissertation aim to improve estimation of signals where significant uncertainty would normally introduce error. Such signals could be electrical (e.g. voltages, currents, etc.), mechanical (e.g. accelerations, forces, etc.), or the like. Estimation is accomplished by addressing the problem probabilistically through information fusion. The proposed techniques not only improve state estimation, but also effectively "learn" about the system of interest in order to further refine estimation. Potential uses of such methods could be found in search-and-rescue robotics, robust control algorithms, and the like. The proposed framework is well-suited for any context where traditional estimation methods have difficulty handling heightened uncertainty.
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Baltas, Evangelos A. "A state space model for river routing." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/21266.
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Olivares, Espinosa Hugo. "Steady-state model of neutron star crust." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21975.
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The advent of X-ray astronomy has turned the study of compact objects into one of the most active research fields in modern-day physics. Diverse luminosity phenomena have been remarked upon in neutron stars and it is believed that in many of them the neutron star crust plays a critical role. This work presents a steady-state model for the neutron star crust that describes, in particular, the profiles of temperature and flux along this region. It is divided as follows: First, a review of observational phenomena in neutron stars, where crust characteristics are thought to be crucial, are presented, alongside general aspects of the theoretical models applied. Second, the different elements that are needed to construct this model are considered. Third, the set of structure equations to be resolved and the calculations of the components of these equations are provided. Finally, the results are shown and discussed and the conclusion is presented.L'avènement de l'astronomie des rayons X a transformé l'étude des objets compacts en un des champs de recherche des plus actifs en physique moderne. Divers phénomènes de luminosité ont été observés dans les étoiles neutron et on estime que la croûte de l'étoile neutron joue un rôle important dans beaucoup de ces phénomènes. Cet ouvrage présente un modèle d'équilibre stable pour la croûte de l'étoile neutron qui décrit, en particulier, les profiles de température et flux dans cette région. L'ouvrage est divisé comme suit: Premièrement, une révision des phénomènes observés dans les étoiles neutron, où les caractéristiques de la croûte sont supposées être cruciaux, est présentée, avec les aspects généraux des modèles théoriques utilisés. Deuxièmement, les différents éléments nécessaires pour construire ce modèle sont examinés. Troisièmement, l'ensemble des équations de structure à résoudre et les calculs des composantes de ces équations sont présentés. Finalement, les résultats sont montrés et discutés et la conclusion est présentée.
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Putrus, G. A. "A laboratory model solid-state VAR compensator." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534766.
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Beattie, Valerie L. "Hidden Markov Model state-based noise compensation." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259519.
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Kumar, Rahul. "Load Balancing Parallel Explicit State Model Checking." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd455.pdf.
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Neff, Angela R. "Bayesian Two Stage Design Under Model Uncertainty." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30303.
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Traditional single stage design optimality procedures can be used to efficiently generate data for an assumed model y = f(x(m),b) + ε. The model assumptions include the form of f, the set of regressors, x(m) , and the distribution of ε. The nature of the response, y, often provides information about the model form (f) and the error distribution. It is more difficult to know, apriori, the specific set of regressors which will best explain the relationship between the response and a set of design (control) variables x. Misspecification of x(m) will result in a design which is efficient, but for the wrong model.
A Bayesian two stage design approach makes it possible to efficiently design experiments when initial knowledge of x(m) is poor. This is accomplished by using a Bayesian optimality criterion in the first stage which is robust to model uncertainty. Bayesian analysis of first stage data reduces uncertainty associated with x(m), enabling the remaining design points (second stage design) to be chosen with greater efficiency. The second stage design is then generated from an optimality procedure which incorporates the improved model knowledge. Using this approach, numerous two stage design procedures have been developed for the normal linear model. Extending this concept, a Bayesian design augmentation procedure has been developed for the purpose of efficiently obtaining data for variance modeling, when initial knowledge of the variance model is poor.Ph. D.
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Brammer, Kenneth W. "A transient state maintenance requirements planning model." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/74512.
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A model is developed for use by logistics planners in determining period by period maintenance requirements for repairable item populations. The model generates maintenance requirements with respect to manpower and facility requirements and spare parts requirements. The model is capable of capturing nonsteady-state failure behavior of populations of repairable items. Each item within the population is broken down into one or more families of components and subcomponents that can have different failure/repair characteristics. Probability of component failure may be generally distributed. A specific data requirement for the model is established. The model is structured to allow the user to conduct various"what if gaming" through an iterative procedure on a personal computer.
This research document includes a literature review that establishes a history of logistics modeling. The literature review provides impetus to the proposed research by defining a need for a transient state model for maintenance requirements planning. The model is validated by a case study involving the generation of maintenance requirements for a case population.Master of Science
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Samara, Marko. "Limit Theorems for the Rotational Isomeric State Model." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322578686.
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Ånstrand, Melina. "State of mind." Thesis, Konstfack, Textil, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-3563.
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Den här uppsatsen är uppbygd så att den följer min konsnärliga och personliga utveckling under tiden på konstfack. Den första delen innehåller en teoridel som sedan följs upp av beskrivningar av mina arbeten. Parallellt med detta löper en berättande text om mitt liv och min relation till kläder som jag haft innan jag började på Konstfack.Textil formgivning / Master 2009 Textile in the Expanded Field
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Frühwirth-Schnatter, Sylvia. "Data Augmentation and Dynamic Linear Models." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 1992. http://epub.wu.ac.at/392/1/document.pdf.
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We define a subclass of dynamic linear models with unknown hyperparameters called d-inverse-gamma models. We then approximate the marginal p.d.f.s of the hyperparameter and the state vector by the data augmentation algorithm of Tanner/Wong. We prove that the regularity conditions for convergence hold. A sampling based scheme for practical implementation is discussed. Finally, we illustrate how to obtain an iterative importance sampling estimate of the model likelihood. (author's abstract)Series: Forschungsberichte / Institut für Statistik
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González, Jorge, and Francisco Casacuberta. "Phrase-based finite state models." Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2008/2720/.
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In the last years, statistical machine translation has already demonstrated its usefulness within a wide variety of translation applications. In this line, phrase-based alignment models have become the reference to follow in order to build competitive systems. Finite state models are always an interesting framework because there are well-known efficient algorithms for their representation and manipulation. This document is a contribution to the evolution of finite state models towards a phrase-based approach. The inference of stochastic transducers that are based on bilingual phrases is carefully analysed from a finite state point of view. Indeed, the algorithmic phenomena that have to be taken into account in order to deal with such phrase-based finite state models when in decoding time are also in-depth detailed.
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Hemmati, Sahar. "Steady-State Co-Kriging Models." Thesis, West Virginia University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10614907.
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In deterministic computer experiments, a computer code can often be run at different levels of complexity/fidelity and a hierarchy of levels of code can be obtained. The higher the fidelity and hence the computational cost, the more accurate output data can be obtained. Methods based on the co-kriging methodology Cressie (2015) for predicting the output of a high-fidelity computer code by combining data generated to varying levels of fidelity have become popular over the last two decades. For instance, Kennedy and O’Hagan (2000) first propose to build a metamodel for multi-level computer codes by using an auto-regressive model structure. Forrester et al. (2007) provide details on estimation of the model parameters and further investigate the use of co-kriging for multi-fidelity optimization based on the efficient global optimization algorithm Jones et al. (1998). Qian and Wu (2008) propose a Bayesian hierarchical modeling approach for combining low-accuracy and high-accuracy experiments. More recently, Gratiet and Cannamela (2015) propose sequential design strategies using fast cross-validation techniques for multi-fidelity computer codes.
This research intends to extend the co-kriging metamodeling methodology to study steady-state simulation experiments. First, the mathematical structure of co-kriging is extended to take into account heterogeneous simulation output variances. Next, efficient steady-state simulation experimental designs are investigated for co-kriging to achieve a high prediction accuracy for estimation of steady-state parameters. Specifically, designs consisting of replicated longer simulation runs at a few design points and replicated shorter simulation runs at a larger set of design points will be considered. Also, design with no replicated simulation runs at long simulation is studied, along with different methods for calculating the output variance in absence of replicated outputs.
Stochastic co-kriging (SCK) method is applied to an M/M/1, as well as an M/M/5 queueing system. In both examples, the prediction performance of the SCK model is promising. It is also shown that the SCK method provides better response surfaces compared to the SK method.
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Huang, Xin, and 黃昕. "Exploring critical-state behaviour using DEM." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206742.
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The critical state soil mechanics (CSSM) framework originally proposed by Schofield & Wroth (1968) has been shown to capture the mechanical behaviour of soils effectively. The particulate implementation of the discrete element method (DEM) can replicate many of the complex mechanical characteristics associated with sand. This research firstly shows that the CSSM framework is useful to assess whether a DEM simulation gives a response that is representative of a real soil. The research then explores the capacity of DEM to extend understanding of soil behaviour within the CSSM framework.
The influence of sample size on the critical-state response observed in DEM simulations that use rigid-wall boundaries was examined. The observed sensitivity was shown to be caused by higher void ratios and lower contact densities adjacent to the boundaries. When the void ratio (e) and mean stress (p’) of the homogeneous interior regions were considered, the influence of sample size on the position of the critical state line (CSL) in e-log(p’) space diminished.
A parametric study on the influence of the interparticle friction (μ) on the load-deformation response was carried out. The macro-scale stress-deformation characteristics were nonlinearly related to μ and the particle-scale measures (fabric, contact force distribution, etc.) varied systematically with μ. The limited effect of increases in μ on the overall strength at high μ values (μ>0.5) is attributable to transition from sliding-dominant to rolling-dominant contact behaviour. A μ value higher than 0.5 leads to a CSL in e-log(p’) space that does not capture real soil response.
True-triaxial simulations with different intermediate stress ratios (b) were performed. The dependency of strength on b agreed with empirical failure criteria for sands and was related to a change of buckling modes of the strong force chains as b increased. DEM simulations showed that the position of the CSL in e-log(p’) space depends on the intermediate stress ratio b. This sensitivity seems to be related to the dependency of the directional fabric anisotropy on b. The link between the state parameter and both soil strength and dilatancy proposed by Jefferies & Been (2006) was reproduced in DEM simulations.
A new rotational resistance model was proposed and it was shown that the new model can qualitatively capture the influence of particle shape on the mechanical behaviour of sand. However, it was shown that the effect of rotational resistance is limited and to quantitatively compare the DEM simulation results with laboratory testing data, e.g., the critical-state loci, it is necessary to use non-spherical particles.published_or_final_version
Civil Engineering
Doctoral
Doctor of Philosophy
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Smrčka, Pavel. "Analýza efektivnosti poboček cestovní kanceláře pomocí DEA modelů." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-72260.
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In today's fiercely competitive environment, not only in the tourism sector, we see a rise in the need to identify the weak and strong sides of the performance of the entire branch network of a travel agency, as well as of its components, the particular branches. This problem can be approached using the process of benchmarking. This method is currently widely used to compare the similarly behaving systems and processes in all areas of human activity. Data envelopment analysis models can be used as one of the methods of benchmarking. This thesis deals first with the theoretical description of the basic models of data envelopment analysis. It then moves on to concentrate on the description of the network-based models, which are then used in the practical part of the thesis. In this last part, it compares selected travel agency branches and identifies the deficiencies in particular areas of their performance.
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Yan, Jun. "Constrained model predictive control, state estimation and coordination." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3206875.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed May 3, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 106-110).
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Sudharatna, Yuraporn. "Towards a stage model of learning organization development." Title page, table of contents and abstract only, 2004. http://hdl.handle.net/2440/37968.
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Becoming a Learning Organization (LO) is widely recognized as a process through which organizations can develop characteristics that enable them to be competitive in an increasingly competitive business environment. While there is an assumption that LOs have the ability to manage change, few empirical studies are available to prove whether an organization with strong LO characteristics also has a high level of change readiness. In developing itself into an LO, an organization seems to gain possession of relevant characteristics through knowledge acquisition, knowledge sharing and knowledge utilization. There is, however, a lack of clarity on what LO characteristics are developed at each of the three stages. The relationship among these stages is also confusing. The purpose of this research is to confirm whether organizations with a high level of LO characteristics also have a high level of readiness-to-change. It also attempts to verify the relationship among the LO development stages of knowledge acquisition, knowledge sharing and knowledge utilization. A questionnaire has been designed following an extensive review. It incorporates "an Inventory of LO Characteristics" to measure the level of LO characteristics formed in an organization. There are also questionnaire to gauge the level readiness-to-change. The questionnaire has been distributed to employees in two leading mobile phone service companies in Thailand. The industry is selected because of its changing business environment. Thailand has been chosen for as the location for the research because few studies in LO have been conducted outside the more developed economies. The findings demonstrate two major insights. Firstly, the correlation coefficient between the six categories of LO characteristics - cultural values, leadership commitment and empowerment, communication, knowledge transfer, employee characteristics and performance upgrading - and readiness-to-change confirms that if an organization has a high level of LO characteristics, it will also have a high level of readiness-to-change. Secondly, the correlation coefficient between the three LO development stages - of knowledge acquisition, knowledge sharing and knowledge utilization - and readiness-to-change, support the hypothesis that they follow a sequential order. Results of the research are analysed and discussed, providing valuable contributions to both research and practice in the area.Thesis (Ph.D.)--Adelaide Graduate School of Business, 2004.
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Jorgensen, Joni Renee. "Ground verification of a multi-stage deployment model." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433470.
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Xu, Bing. "A discrete nonlinear model of state-structured populations." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187276.
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We consider in this dissertation a general class of nonlinear matrix models for stage-structured populations competing for a single (unstructured) resource. Individuals in such a population are characterized by a scalar variable (e.g., age, size) and are classified into a finite number of classes. The models are treated with sufficient generality so that transitions between any two classes are permitted (the sole constraint being that all newborns lie in the same class). The nonlinearities, which arise from the density dependence of fertility rates, survival rates and transition probabilities between classes, are introduced by assuming that the class-specific birth rates and survival rates are functions of the total population density and the number of individuals in higher or lower ranking classes. This assumption enables us to derive a scalar difference equation for the total population size. The proposed models are used to study intra-competition and intra-predation (cannibalism) populations with constant or varying resources. In both cases, we study the existence and stability of equilibria for the total population size when by means the bifurcation parameter π, known as the inherent net reproduction value, varies. The intra-specific competition models include contest and scramble competitions as two extreme cases. We show that contest competition is always "more stable" than scramble competition in the sense that it yields higher equilibrium levels and larger stability regions (all other factors being identical). We also show, under certain restrictions, that near π = 1 scramble competition has higher equilibrium resilience than contest competition. The size-structured model for the dynamics of a cannibalistic population is derived under the assumption that cannibals attack only smaller victims, as is generally the case in the biological world. By incorporating the positive-negative feedback mechanism resulting from cannibalism, our analysis yields many dynamical features that have been attributed to cannibalism in the literature, including density self-regulation, a "life-boat strategy" phenomenon and multiple stable positive equilibrium states and hysteresis.
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Van, Huyssteen Petrus. "An implementation model for inter-state peacekeeping operations." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53266.
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Thesis (MPA)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Since the advent of democracy in 1994, domestic and international expectations have steadily grown regarding the role of a new South African as a responsible and respected member of the international community. These expectations have included the hope that South Africa will playa leading role in a variety of international, regional and sub-regional forums and that the country will become an active participant in attempts to resolve various regional and international conflicts. The nature of international activities aimed at international conflict prevention, management and resolution has changed dramatically over the past decade. A radically post-Cold War security environment has seen the transformation of classical peacekeeping operations into complex, multi-dimensional conflict management activities with a political focus in which the military is but one of many participants. Whilst South Africa has, as a member of bodies such as the United Nations, the Organisation of African Unity, the African Union and the Southern African Development Community, begun to play an active role in diplomatic resolution initiatives, the country is also expected to contribute to wider multi-national peace missions. Contemporary peace missions are fundamentally political initiatives, despite the complex mixture of political, humanitarian and military concerns and means. South Africa must therefore make a careful appraisal of the political and strategic environment within which peace missions are to be launched and the principles governing South African participation in such efforts. A clear understanding is required of the type of mandate, which governs peace missions in order to facilitate a detailed articulation of acceptable entry and exit criteria and to determine the scope, level and type of resources that South Africa is willing to commit to future peace missions. This will provide a clear indication to the international community and the regional and sub-regional partners of South Africa's stance on participation in peace operations. South Africa has limited but valuable resources to offer the international community for the conduct of peace missions. These include civilians with a diverse range of skills and experience appropriate to peace processes, professional and experienced police officers and well trained and disciplined military capacity. If these resources are to be utilised by the international community in the cause of peace, their approximate nature and size must be defined through an appropriate readiness system for each component. On the other hand, a number of key conditions must be met before these potential resources are deployed in support of a particular peace mission. Some of the responsibility for meeting these conditions lies at the level of the international community - such as the formulation of a clear and realistic mandate. On the other hand, it is a national obligation to support and budget for such participation. After an assessment of the South African National Defence Force, operation BOLEAS in Lesotho, a clearly articulated Aide de Memoire is recommended as a model for Peace Support Operations, which will cover all aspects in relation to South African National Defence (SANDF) participation in peace initiatives. This Aide De Memoire aim to set conditions that should be met before any peacekeeping operation can be implemented. It will provide clarity on matters relating to the scope of South African peace missions; the question of mandates, joint task organisation and legal responsibilities.
AFRIKAANSE OPSOMMING: Sedert die aanvang van demokrasie in 1994 was daar 'n stelselmatige groei in eie en internasionale verwagtinge oor die rol van 'n nuwe Suid-Afrika as verantwoordelike en gerespekteerde lid van die internasionale gemeenskap. Hierdie verwagtinge het die hoop ingesluit dat Suid-Afrika "n leidende rol sou speel in 'n verskeidenheid van internasionale, streek en sub-streek forums en dat die land 'n aktiewe rolspeler sal word in pogings om oplossings te vind vir verskeie streeks- en internasionale konflikte. Die aard van internasionale bedrywighede, wat gemik was op die voorkoming van internasionale konflik, bestuur en besluitneming, het oor die laaste dekade drasties verander. 'n Radikale post-koue oorlogse sekerheidsomgewing het die transformasie beleef vanaf klassieke vredesoperasies na komplekse, multi-dimensionele konflikhanteringsaktiwiteite met 'n politieke fokus waarin die militêre arm van die staat maar een van baie deelnemers is. Terwyl Suid-Afrika, as lid van organisasies soos die Verenigde Nasies, die Organisasie van Afrika Eenheid en die Suider-Afrikaanse Ontwikkelingsgemeenskap, 'n meer aktiewe rol begin speel het in diplomatieke besluitnemingsinisiatiewe, word daar ook van die land verwag om 'n bydrae te lewer by groter multi-nasionale vredesendings. Kontemporêre vredesendings is in beginsel politieke inisiatiewe, ten spyte van die komplekse mengsel van politieke, humanitêre en militêre belange en middele. Suid- Afrika is dus verplig om 'n versigtige beoordeling te maak van die politieke en strategiese omgewing waarin vredesoperasies hul afspeel, asook die beginsels wat Suid-Afrikaanse deelname aan hierdie pogings vereis. 'n Juiste begrip van die tipe mandaat wat vredesendings beheer, word vereis sodat 'n gedetailleerde uitspraak van aanvaarbare toetree- en uittreemaatstawwe vergemaklik kan word. Ook die bestek, vlak en tipe van hulpbronne waartoe Suid-Afrika bereid is om homself in die toekoms te verbind moet bepaal word. Dit sal 'n duidelike aanduiding vir die internasionale gemeenskap, streek en substreekvennote gee van wat Suid-Afrika se standpunt ten opsigte van deelname aan vredesoperasies is. Suid-Afrika het beperkte maar waardevolle hulpbronne wat aan die internasionale gemeenskap gebied kan word vir die uitvoering van vredesendings. Dit sluit in: burgerlikes met 'n verskeidenheid van vaardighede en ondervinding wat geskik is vir vredesprosesse; ervare en professionele beleidmakers, asook goed opgeleide en gedissiplineerde militêre vermoëns. Indien hierdie bronne deur die internasionale gemeenskap in die bevordering van vrede aangewend sou word, moet die beraamde aard en omvang daarvan vasgestel word met behulp van 'n toepaslike gereedheidstelsel vir elke komponent. Aan die ander kant moet 'n aantal sleutelvereistes nagekom word voordat hierdie potensiële hulpbronne as steun vir 'n spesifieke vredesending ontplooi word. Sekere verantwoordelikhede om by die beginsels te hou, berus op die vlak van die internasionale gemeenskap - soos die formulering van 'n duidelike en realistiese mandaat. Dit is egter 'n nasionale verantwoordelikheid om vir so 'n deelname te begroot en dit te ondersteun. Na die beoordeling van OPERASIE BOLEAS deur die Suid-Afrikaanse Nasionale Weermag, stel die navorsing 'n duidelik geartikuleerde Aide de Memoire vir Vredesteunoperasies voor wat alle aspekte in verband met die Suid-Afrikaanse Weermag se deelname aan vredesinisiatiewe sal insluit. Hierdie Aide de Memoire beoog om voorwaardes te stel wat nagekom moet word voordat enige vredesoperasies geïmplimenteer kan word. Dit sal duidelikheid verskaf oor aangeleenthede rakende die bestek van Suid-Afrikaanse vredesendings; die kwessie van mandate; gesamentlike taakorganisasie en regsverantwoordelikhede.
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Saouma, Sophie M. "Lebanon and Hizbullah: Investigating the Failed State Model." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/scripps_theses/504.
Full textAbstract:
This thesis investigates the failed state label on Lebanon. The thesis explores how Lebanon falls under the paradigm and how Lebanon contradicts, at times, the failed state model with the inclusion of Hizbullah.
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Melo, Andrés Felipe. "A state-action model for design process planning." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619610.
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