Дисертації з теми "Multi-Group models"
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1
Jin, Shaobo. "Essays on Estimation Methods for Factor Models and Structural Equation Models." Doctoral thesis, Uppsala universitet, Statistiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-247292.
Анотація:
This thesis which consists of four papers is concerned with estimation methods in factor analysis and structural equation models. New estimation methods are proposed and investigated. In paper I an approximation of the penalized maximum likelihood (ML) is introduced to fit an exploratory factor analysis model. Approximated penalized ML continuously and efficiently shrinks the factor loadings towards zero. It naturally factorizes a covariance matrix or a correlation matrix. It is also applicable to an orthogonal or an oblique structure. Paper II, a simulation study, investigates the properties of approximated penalized ML with an orthogonal factor model. Different combinations of penalty terms and tuning parameter selection methods are examined. Differences in factorizing a covariance matrix and factorizing a correlation matrix are also explored. It is shown that the approximated penalized ML frequently improves the traditional estimation-rotation procedure. In Paper III we focus on pseudo ML for multi-group data. Data from different groups are pooled and normal theory is used to fit the model. It is shown that pseudo ML produces consistent estimators of factor loadings and that it is numerically easier than multi-group ML. In addition, normal theory is not applicable to estimate standard errors. A sandwich-type estimator of standard errors is derived. Paper IV examines properties of the recently proposed polychoric instrumental variable (PIV) estimators for ordinal data through a simulation study. PIV is compared with conventional estimation methods (unweighted least squares and diagonally weighted least squares). PIV produces accurate estimates of factor loadings and factor covariances in the correctly specified confirmatory factor analysis model and accurate estimates of loadings and coefficient matrices in the correctly specified structure equation model. If the model is misspecified, robustness of PIV depends on model complexity, underlying distribution, and instrumental variables.
2
Li, Fengfeng. "Multi-criteria optimization of group replacement schedules for distributed water pipeline assets." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/66195/1/Fengfeng_Li_Thesis.pdf.
Анотація:
This thesis presents a multi-criteria optimisation study of group replacement schedules for water pipelines, which is a capital-intensive and service critical decision. A new mathematical model was developed, which minimises total replacement costs while maintaining a satisfactory level of services. The research outcomes are expected to enrich the body of knowledge of multi-criteria decision optimisation, where group scheduling is required. The model has the potential to optimise replacement planning for other types of linear asset networks resulting in bottom-line benefits for end users and communities. The results of a real case study show that the new model can effectively reduced the total costs and service interruptions.
3
Qi, Hui, University of Western Sydney, of Science Technology and Environment College, and School of Computing and Information Technology. "Multi-polynomial higher order neural network group models for financial data and rainfall data simulation and prediction." THESIS_CSTE_CIT_Qi_H.xml, 2001. http://handle.uws.edu.au:8081/1959.7/343.
Анотація:
Multi-Polynomial Higher Order Neural Network Group Models (MPHONNG) program developed by the author will be studied in this thesis. The thesis also investigates the use of MPHONNG for financial data and rainfall data simulation and prediction. The MPHONNG is combined with characteristics of Polynomial function, Trigonometric polynomial function and Sigmoid polynomial function. The models are constructed with three layers Multi-Polynomial Higher Order Neural Network and the weights of the models are derived directly from the coefficents of the Polynomial form, Trignometric polynomial form and Sigmoid polynomial form. To the best of the authors knowledge, it is the first attempt to use MPHONNG for financial data and rainfall data simulation and prediction. Results proved satisfactory, and confirmed that MPHONNG is capable of handling high frequency, high order nonlinear and discontinuous data.Master of Science (Hons)
4
Qi, Hui. "Multi-polynomial higher order neural network group models for financial data and rainfall data simulation and prediction." Thesis, View thesis View thesis, 2001. http://handle.uws.edu.au:8081/1959.7/343.
Анотація:
Multi-Polynomial Higher Order Neural Network Group Models (MPHONNG) program developed by the author will be studied in this thesis. The thesis also investigates the use of MPHONNG for financial data and rainfall data simulation and prediction. The MPHONNG is combined with characteristics of Polynomial function, Trigonometric polynomial function and Sigmoid polynomial function. The models are constructed with three layers Multi-Polynomial Higher Order Neural Network and the weights of the models are derived directly from the coefficents of the Polynomial form, Trignometric polynomial form and Sigmoid polynomial form. To the best of the authors knowledge, it is the first attempt to use MPHONNG for financial data and rainfall data simulation and prediction. Results proved satisfactory, and confirmed that MPHONNG is capable of handling high frequency, high order nonlinear and discontinuous data.
5
Qi, Hui. "Multi-polynomial higher order neural network group models for financial data and rainfall data simulation & prediction /." View thesis View thesis, 2001. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030328.121924/index.html.
Анотація:
Thesis (M.Sc. (Hons.))--University of Western Sydney, 2001."A thesis presented to the Department of Computing and Information Systems, University of Western Sydney, Macarthur in partial fulfilment of the requirements for the degree of Master of Science (Honours)" Bibliography : leaves 129-139.
6
Yacheur, Souâd. "Modélisation et étude mathématique de la propagation d’une maladie vectorielle (paludisme) au sein d’une population." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0311.
Анотація:
L’objectif de cette thèse est l’étude d’une classe de modèles mathématiques décrivant quelques problèmes relatifs à l’infection par le parasite Plasmodium falciparum qui cause le paludisme et dont le vecteur est le moustique.On divise le travail en trois grandes parties, la première partie concerne l’analyse de la propagation du paludisme au sein d’une population isolé. On a étudié la stabilité globale de l'équilibre sans maladie en fonction des différents paramètres épidémiologiques quand nombre de reproduction de base est inférieur à un. Quand ce nombre est supérieur à on a prouvé l’existence d’un unique équilibre endémique. En s'inspirant de l'approche géométrique introduite par Li et Muldowney, on a donné une condition suffisante pour que cet équilibre endémique soit globalement asymptotiquement stable.Un estimateur d'état est construit dans le but d'estimer la taille des différentes classes des populations humaines en utilisant la mesure du nombre de nouveaux humains infectés par unité de temps. Nous avons aussi proposé deux stratégies de contrôle pour éradiquer la maladie. Enfin pour mieux comprendre la dynamique de propagation de la maladie et pour désigner les paramètres les plus influençant, nous avons fait l'étude de la sensibilité locale du nombre de reproduction de base par rapport à chaque paramètre. La deuxième partie est dédiée à l’étude d’un modèle qui décrit l’interaction et la propagation de la maladie au sein d’une population humaine divisée en deux sous-population locaux et non-locaux, la première sous-population suit une croissance linéaire quant à la population des non-locaux suit une croissance logistique au sein de la première. Nous faisons le choix d'étudier l'impact de la migration des personnes d'un pays endémique vers un autre pays déclaré sans maladie ou vers l'éradication de la maladie. Notre analyse a donné des conditions de la persistance de la maladie, nous avons étudié la possibilité de contrôle de la maladie dans un premier temps à travers le contrôle de la capacité limite, puis nous avons développé une méthode basée sur une matrice dite matrice de transmission vectorielle qui a servi à déterminer le lien entre les deux sous-populations et la population des moustiques, et en fonction des valeurs d'entrée de cette dernière dans le but de contrôler la maladie. Par ailleurs une étude de sensibilité locale et globale du niveau d'infecté locaux et non-locaux a été faite pour déterminer les paramètres d'entrées du modèle les plus influençant. La dernière partie est consacrée à l’étude de la dynamique globale des modèles avec de multiples sous-populations qui sont supposés faiblement inter-connectées. Notre travail met en évidence une procédure qui permet d'avoir une analyse complète de beaucoup de systèmes dynamiques modélisant la propagation d'une maladie qui fait intervenir différentes populations. Le but est de pouvoir déterminer la stabilité globale de l'équilibre sans maladie quand le nombre de reproduction de base est inférieur à un ainsi que la stabilité globale des différents types (intérieurs ou frontière) des équilibres endémiques en fonction des différents nombres de reproduction de base locaux et de la nature des interconnexions entre les composantes du réseauThe main purpose of this thesis is to study a class of mathematical models describing some problems related to the infection by the Plasmodium falciparum parasite which causes malaria and whose vector is the mosquito.The work is divided into three main parts, the first part is related to the analysis of the spread of malaria in an isolated population. The global stability of the disease-free equilibrium is studied according to the different epidemiological parameters when the number of basic reproduction is lower than one. When this number is higher than one, the existence of a unique endemic equilibrium is proved. Inspired by the geometric approach introduced by Li and Muldowney, we provided a sufficient condition for this endemic equilibrium to be globally asymptotically stable.A state estimator was constructed to estimate the size of human populations based on the measurement of the number of newly infected humans per unit time. We also proposed two control strategies to eradicate the disease.Finally, to better understand the dynamics of the spread of the disease and to identify the most influential parameters, we have studied the local sensitivity of the number of basic reproduction with respect to each parameter.The second part is about the study of a model that describes the interaction and the spread of the disease within a human population that is divided into two subpopulations, local and non-local. The first subpopulation follows a linear growth while the non-local population follows a logistic growth among the first. We choose to study the impact of the migration of people from an endemic country to another country declared free of the disease or towards the eradication of the disease.Our analysis yielded conditions of the persistence of the disease, we studied the possibility of controlling the disease in a first step through the control of the carrying capacity, then we developed a method based on a matrix called matrix of vectorial transmission which was used to determine the link between the two subpopulations and the population of mosquitoes, according to the values of this matrix entries in order to ensure the control of the disease spread. In addition, a local and global sensitivity study of the level of local and non-local infection was performed to determine the most influential model input parameters.The last part is devoted to the study of the global dynamics of models with multiple subpopulations that are assumed to be weakly interconnected. Our work highlights a process that allows us to perform a complete analysis of many dynamical systems modeling the spread of a disease that involves different populations. The objective is to be able to determine the global stability of the disease-free equilibrium when the basic reproduction number is less than one as well as the global stability of the different types (interior or frontier) of endemic equilibria as a function of the different local basic reproduction numbers and the nature of the interconnections between the network components
7
Porst, Roland. "A new transit system and conceptual models with associated findings to improve urban transport." Thesis, Queensland University of Technology, 2002.
8
Hall, William S. "The Battle Group Logistics Comparative Analysis Model (BGLCAM) : a comparative analysis tool for multi-battle group logistics support." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA341120.
Анотація:
Thesis (M.S. in Operations Research) Naval Postgraduate School, September 1997."September 1997." Thesis advisor(s): Mark A. Youngren. Includes bibliographical references (p. 33). Also available online.
9
Shi, Jun-Mei, Ulrich Rohde, and Horst-Michael Prasser. "Validation of the multiple velocity multiple size group (CFX10.0 N x M MUSIG) model for polydispersed multiphase flows." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28031.
Анотація:
To simulate dispersed two-phase flows CFD tools for predicting the local particle number density and the size distribution are required. These quantities do not only have a significant effect on rates of mixing, heterogeneous chemical reaction rates or interfacial heat and mass transfers, but also a direct relevance to the hydrodynamics of the total system, such as the flow pattern and flow regime. The Multiple Size Group (MUSIG) model available in the commercial codes CFX-4 and CFX-5 was developed for this purpose. Mathematically, this model is based on the population balance method and the two-fluid modeling approach. The dispersed phase is divided into N size classes. In order to reduce the computational cost, all size groups are assumed to share the same velocity field. This model allows to use a sufficient number of particle size groups required for the coalescence and breakup calculation. Nevertheless, the assumption also restricts its applicability to homogeneous dispersed flows. We refer to the CFX MUSIG model mentioned above as the homogeneous model, which fails to predict the correct phase distribution when heterogeneous particle motion becomes important. In many flows the non-drag forces play an essential role with respect to the bubble motion. Especially, the lift force acting on large deformed bubbles, which is dominated by the asymmetrical wake, has a direction opposite to the shear induced lift force on a small bubble. This bubble separation cannot be predicted by the homogeneous MUSIG model. In order to overcome this shortcoming we developed an efficient inhomogeneous MUSIG model in cooperation with ANSYS CFX. A novel multiple velocity multiple size group model, which incorporates the population balance equation into the multi-fluid modeling framework, was proposed. The validation of this new model is discussed in this report.
10
Shi, Jun-Mei, Ulrich Rohde, and Horst-Michael Prasser. "Validation of the multiple velocity multiple size group (CFX10.0 N x M MUSIG) model for polydispersed multiphase flows." Forschungszentrum Dresden-Rossendorf, 2007. https://hzdr.qucosa.de/id/qucosa%3A21630.
Анотація:
To simulate dispersed two-phase flows CFD tools for predicting the local particle number density and the size distribution are required. These quantities do not only have a significant effect on rates of mixing, heterogeneous chemical reaction rates or interfacial heat and mass transfers, but also a direct relevance to the hydrodynamics of the total system, such as the flow pattern and flow regime. The Multiple Size Group (MUSIG) model available in the commercial codes CFX-4 and CFX-5 was developed for this purpose. Mathematically, this model is based on the population balance method and the two-fluid modeling approach. The dispersed phase is divided into N size classes. In order to reduce the computational cost, all size groups are assumed to share the same velocity field. This model allows to use a sufficient number of particle size groups required for the coalescence and breakup calculation. Nevertheless, the assumption also restricts its applicability to homogeneous dispersed flows. We refer to the CFX MUSIG model mentioned above as the homogeneous model, which fails to predict the correct phase distribution when heterogeneous particle motion becomes important. In many flows the non-drag forces play an essential role with respect to the bubble motion. Especially, the lift force acting on large deformed bubbles, which is dominated by the asymmetrical wake, has a direction opposite to the shear induced lift force on a small bubble. This bubble separation cannot be predicted by the homogeneous MUSIG model. In order to overcome this shortcoming we developed an efficient inhomogeneous MUSIG model in cooperation with ANSYS CFX. A novel multiple velocity multiple size group model, which incorporates the population balance equation into the multi-fluid modeling framework, was proposed. The validation of this new model is discussed in this report.
11
Almulhim, Tarifa Saleh M. "Development of a hybrid fuzzy multi-criteria decision making model for selection of group health insurance plans." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/development-of-a-hybrid-fuzzy-multicriteria-decision-making-model-for-selection-of-group-health-insurance-plans(9e687f14-38df-45dd-9315-70d18aac6455).html.
Анотація:
A group health insurance plan is an insurance plan that provides healthcare coverage to a selected group of people. In various countries, group health insurance plans are one of the major benefits offered through employers in the private sector. In recent years, the numbers of group health insurance plans offered in the market of health insurance have been increasing rapidly. This is due to compulsory government policies, which are imposed on employers in the private sector leading to an increasing demand for this insurance plan. Accordingly, employers may face a wide variety of available group health insurance plan alternatives. Despite the fact that employers in the private sector have a crucial and significant role in the health insurance market all over the world, little is known about how employers evaluate and choose group health insurance plans to cover their employees against the payments of benefits as a result of sickness or injury. Therefore, the primary concern in this research is to propose a model to assist employers within the private sector to evaluate alternative group health insurance plans and to select the most appropriate, in order to provide the perfect health care environment for their employees. In this research, a new hybrid Fuzzy Multiple Criteria Decision Making (MCDM) model is proposed for the selection problem. The proposed model tackles some issues that may be associated with the selection of the group health insurance plan, such as modelling uncertainty, studying the dependence among decision attributes, deriving decision attributes importance weights and ranking various alternatives. In the proposed hybrid model, four extension approaches based on the Fuzzy Delphi, Fuzzy Decision Making Trial and Evaluation Laboratory (DEMATEL), Fuzzy Group Prioritisation and Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods are developed. Unlike the existing methods, the four proposed approaches, a new extended Fuzzy Delphi (FDE) method, a new extended Fuzzy DEMATEL method, a new Fuzzy Group Prioritisation (FGP) method and a new extended Fuzzy TOPSIS method, consider the importance weight of each member in group decision making since the selection problem needs evaluations from decision makers (DMs) with different levels of expertise and different perceptions. In the literature, there is some work on these methods, but to our knowledge, no research exists that combines these four methods. Moreover, the proposed model might be applied, due to its novelty, to any MCDM problem uncertainty in different. Furthermore, four new prototype decision support tools, termed Fuzzy Delphi Solver, Fuzzy DEMATEL Solver, Fuzzy Group Prioritisation Solver and Fuzzy TOPSIS Solver were developed in this study, based on the concepts of the four proposed approaches, in order to provide user-friendly interfaces for facilitating the application of these approaches. MATLAB software Version R2013a was adopted as a development environment for prototyping these new decision support tools in this study. The tools developed were validated internally by using hypothetical examples and checking the correctness of the results obtained by comparing them to other results generated from other software, such as Microsoft Excel or LINGO V13.0 software. In addition, a practical validation of the proposed hybrid Fuzzy MCDM model was investigated through conducting a case study of the Saudi health insurance industry. The main objectives of the case study were: 1) investigation of the evaluation process of selecting a group health insurance plan, including identifying the selection criteria and alternatives, studying the dependency issue, deriving the criteria weights, and ranking available alternatives; 2) application of the new decision support tools developed. In this case study, a group of nine DMs, Human Resources (HR) managers at nine different private companies in Saudi Arabia, were selected to take part of this case study. Their involvement achieved the first objective of the case study. At the end of the case study, a sensitivity analysis was conducted to indicate the robustness and the reliability of the results obtained. It is concluded that the proposed model is indeed beneficial. Finally, areas for further research were identified.
12
Pearce, Christopher. "Analysis of heterogeneity in the early and late stages of disease spread for a multi-group SIS model." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576951.
Анотація:
Chapter 1 gives a brief introduction to modelling epidemics in both a deterministic and stochastic framework. Chapter 2 gives a brief introduction to the single-group Susceptible-Infected-Susceptible (SIS) model and we mention and establish all the necessary background theory we apply to the model with the aim of extending these theories and techniques to our own multi-group SIS model in order to obtain results concerning the short and long-term behaviour of the epidemic. In Chapter 3 we define a k-group SIS model which will allow us to examine the effects of heterogeneity in three different categories - the infectivity of infectious individuals, their mixing behaviour and an individual's susceptibility to the disease. In doing this, we describe the dynamics of the model including how to represent it in a deterministic framework, the quasi-stationary distribution and the time to extinction. We apply a branching process approximation to the model, viable for the early stages of a disease, using well established theory. In Chapter 4 we look specifically at the early stages of the epidemic based on the branching process approximation and produce numerical results on how the probability of disease emergence behaves as the basic reproduction number Ra increases. We contrast 2-group heterogeneous models against a homogeneous model, for epidemics assuming either an exponential or constant infectious period. We then analyse these results with an iterative and inductive proof showing that the emergence probability for a heterogeneous model will always be less than that for a homogeneous model, not just in the limit but at all stages of iterative convergence. Next we provide a proof which shows that for the non-separable general model this ordering exists for any given infectious period. We then go on to look at comparing two heterogeneous models to one another under various sets of parameters and use majorization theory as a tool for doing so. We use orderings referred to as ordinary majorization, p-majorization and pq-majorization to show that there is an inferred ordering of emergence probabilities when comparing multi-group he- terogeneous models to one another. In Chapter 5 we study the long-term behaviour of the stochastic multi-group SIS model. We begin by formulating conditions for the general model under which feasible equilibria exist and conditions where either the disease-free or endemic equilibria are stable. For a 2-group version, we calculate numerically the determi- nistic equilibrium values, stochastic means and quasi-stationary distributions for a range of Ra values. We use an Ornstein-Uhlenbeck process to approximate the quasi-stationary distribution and assess the accuracy of the approximation. We then calculate the expected time to extinction and use a coefficient of variation approximation as a proxy for this and discuss the suitability of such an approxi- mation to the exact results. These analyses are all carried out for models which exhibit heterogeneity in infectivity, mixing or susceptibility.
13
Calder, J. A. "Developing multi-family group therapy in schools : an evaluation of the Marlborough Model as a collaborative TAMHS intervention." Thesis, University of Essex, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542356.
14
Johnston-Fisher, Jessica. "Testing a Multi-Level Mediation Model of Workgroup Incivility: The Role of Civility Climate and Group Norms for Civility." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1332.
Анотація:
The purpose of this study was to test a multi-level mediation model of incivility. Specifically, it was proposed that predictors of workplace incivility at the individual, group, and organizational level would be related to each other and negative individual outcomes. It was also proposed that the relationship between these predictors and outcomes would be mediated by workplace incivility victimization. Two hundred twenty eight participants completed an online survey through Amazon’s Mechanical Turk. Results indicated that variables at all three levels (i.e., civility climate, group norms for civility, and individual characteristics) were related to one another and predictive of negative individual outcomes. Results also indicated preliminary support for the mediating role of workplace incivility experiences in these relationships and the overall model. Workplace incivility significantly moderated all of the relationships between predictor and criterion variables. Implications and limitations of these findings are discussed, and several directions for future research on workplace incivility are explored.
15
Baik, Ok Mi. "The Longitudinal Association between Depressive Symptoms and Alcohol Use in Middle-Aged and Older Adults: Comparison by Retirement Status." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1291412716.
16
Mickelson, Bryan K. "Client Change in Multi-Model Treatment: A Comparison of Change Trajectories in Group, Individual, and Conjoint Formats in a Counseling Center." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2758.pdf.
17
Rawat, Rakesh. "User behaviour modelling in a multi-dimensional environment for personalization and recommendation." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/48135/1/Rakesh_Rawat_Thesis.pdf.
Анотація:
Handling information overload online, from the user's point of view is a big challenge, especially when the number of websites is growing rapidly due to growth in e-commerce and other related activities. Personalization based on user needs is the key to solving the problem of information overload. Personalization methods help in identifying relevant information, which may be liked by a user. User profile and object profile are the important elements of a personalization system. When creating user and object profiles, most of the existing methods adopt two-dimensional similarity methods based on vector or matrix models in order to find inter-user and inter-object similarity. Moreover, for recommending similar objects to users, personalization systems use the users-users, items-items and users-items similarity measures. In most cases similarity measures such as Euclidian, Manhattan, cosine and many others based on vector or matrix methods are used to find the similarities. Web logs are high-dimensional datasets, consisting of multiple users, multiple searches with many attributes to each. Two-dimensional data analysis methods may often overlook latent relationships that may exist between users and items. In contrast to other studies, this thesis utilises tensors, the high-dimensional data models, to build user and object profiles and to find the inter-relationships between users-users and users-items. To create an improved personalized Web system, this thesis proposes to build three types of profiles: individual user, group users and object profiles utilising decomposition factors of tensor data models. A hybrid recommendation approach utilising group profiles (forming the basis of a collaborative filtering method) and object profiles (forming the basis of a content-based method) in conjunction with individual user profiles (forming the basis of a model based approach) is proposed for making effective recommendations. A tensor-based clustering method is proposed that utilises the outcomes of popular tensor decomposition techniques such as PARAFAC, Tucker and HOSVD to group similar instances. An individual user profile, showing the user's highest interest, is represented by the top dimension values, extracted from the component matrix obtained after tensor decomposition. A group profile, showing similar users and their highest interest, is built by clustering similar users based on tensor decomposed values. A group profile is represented by the top association rules (containing various unique object combinations) that are derived from the searches made by the users of the cluster. An object profile is created to represent similar objects clustered on the basis of their similarity of features. Depending on the category of a user (known, anonymous or frequent visitor to the website), any of the profiles or their combinations is used for making personalized recommendations. A ranking algorithm is also proposed that utilizes the personalized information to order and rank the recommendations. The proposed methodology is evaluated on data collected from a real life car website. Empirical analysis confirms the effectiveness of recommendations made by the proposed approach over other collaborative filtering and content-based recommendation approaches based on two-dimensional data analysis methods.
18
Gorantla, Malakondayya Choudary. "Design and analysis of group key exchange protocols." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/37664/1/Malakondayya_Gorantla_Thesis.pdf.
Анотація:
A group key exchange (GKE) protocol allows a set of parties to agree upon a common secret session key over a public network. In this thesis, we focus on designing efficient GKE protocols using public key techniques and appropriately revising security models for GKE protocols. For the purpose of modelling and analysing the security of GKE protocols we apply the widely accepted computational complexity approach. The contributions of the thesis to the area of GKE protocols are manifold. We propose the first GKE protocol that requires only one round of communication and is proven secure in the standard model. Our protocol is generically constructed from a key encapsulation mechanism (KEM). We also suggest an efficient KEM from the literature, which satisfies the underlying security notion, to instantiate the generic protocol. We then concentrate on enhancing the security of one-round GKE protocols. A new model of security for forward secure GKE protocols is introduced and a generic one-round GKE protocol with forward security is then presented. The security of this protocol is also proven in the standard model. We also propose an efficient forward secure encryption scheme that can be used to instantiate the generic GKE protocol. Our next contributions are to the security models of GKE protocols. We observe that the analysis of GKE protocols has not been as extensive as that of two-party key exchange protocols. Particularly, the security attribute of key compromise impersonation (KCI) resilience has so far been ignored for GKE protocols. We model the security of GKE protocols addressing KCI attacks by both outsider and insider adversaries. We then show that a few existing protocols are not secure against KCI attacks. A new proof of security for an existing GKE protocol is given under the revised model assuming random oracles. Subsequently, we treat the security of GKE protocols in the universal composability (UC) framework. We present a new UC ideal functionality for GKE protocols capturing the security attribute of contributiveness. An existing protocol with minor revisions is then shown to realize our functionality in the random oracle model. Finally, we explore the possibility of constructing GKE protocols in the attribute-based setting. We introduce the concept of attribute-based group key exchange (AB-GKE). A security model for AB-GKE and a one-round AB-GKE protocol satisfying our security notion are presented. The protocol is generically constructed from a new cryptographic primitive called encapsulation policy attribute-based KEM (EP-AB-KEM), which we introduce in this thesis. We also present a new EP-AB-KEM with a proof of security assuming generic groups and random oracles. The EP-AB-KEM can be used to instantiate our generic AB-GKE protocol.
19
Stadler, Katharina Maria [Verfasser], and Jan von [Akademischer Betreuer] Delft. "A model study of strong correlations in Hund metals : the Numerical Renormalization Group as efficient multi-band impurity solver for Dynamical Mean-Field Theory / Katharina Maria Stadler ; Betreuer: Jan von Delft." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1182228690/34.
20
Platino, Vincenzo. "Contributions sur les économies avec externalités." Thesis, Paris 1, 2014. http://www.theses.fr/2014PA010016.
Анотація:
La thèse porte sur des modèles économiques en présence d’externalités. En suivant Laffont (1988), nous donnons la définition suivante d’externalité.“Effet indirect” signifie que l’effet est créé par un agent économique différent de celui qui est affecté, et que l’effet n’est pas produit par l’intermédiaire du système de prix. Par conséquence, le système des prix ne joue que le rôle d’égaler à l’équilibre l’offre globale et la demande globale. La définition ci-dessus montre que la présence d’effets externes nécessite une nouvelle description des caractéristiques des agents, c’est-à-dire des préférences individuelles, des ensembles de consommation et des ensembles de production des producteurs. La thèse se compose de trois chapitres. Le premier chapitre étudie les restrictions de testabilité d’un modèle spécifique avec des externalités et des biens publics. Dans le deuxième chapitre et le troisième chapitre, nous considérons un modèle d’équilibre général avec des externalités au niveau des préférences individuelles et des ensembles de production des producteurs. Dans le deuxième chapitre nous traitons l’existence d’un équilibre concurrentiel en utilisant un approche différentiable, et dans le troisième chapitre nous donnons un résultat de régularité. Dans le Chapitre 2, nous considérons un modèle d’économie de propriété privée avec des externalités de consommation et de production. En utilisant une approche différentiable, nous prouvons que l’ensemble des équilibres concurrentiels avec des consommations et des prix strictement positifs est non vide et compact. Dans le Chapitre 3, nous considérons des économies de propriété privée avec externalités de consommation et de production. Nous étudions des conditions suffisantes pour la régularité générique de ces économiesWe study the testability implications of public versus private consumption in col-lective models of group consumption. The distinguishing feature of our approach is that we start from a revealed preference characterization of collectively rational behavior. Remarkably, we find that assumptions regarding the public or private nature of specific goods do have testability implications, even if one only observes the aggregate group consumption. In fact, these testability implications apply as soon as the analysis includes three goods and four observations. This stands in sharp contrast with existing results that start from a differential characterization of collectively rational behavior. In our opinion, our revealed preference approach obtains stronger testability conclusions because it focuses on a global characterization of collective rationality, whereas the differential approach starts from a local characterization.We consider a general model of private ownership economies with consumption and production externalities. Each firm is characterized by a technology described by a transformation function. Each household is characterized by a utility function, the shares on firms’ profit and an initial endowment of commodities. Describing equlib-ria in terms of first order conditions and market clearing conditions, and using a homotopy approach based on the seminal work by Smale (1974), under differentiability and boundary conditions, we prove the non-emptiness and the compactness of the set of competitive equilibria with consumptions and prices strictly positive.We consider a general equilibrium model of private ownership economy with con-sumption and production externalities. Each firm is owned by the households and it is characterized by a technology described by a transformation function. Each household is characterized by a utility function, the shares on the firms profits and an endowment of commodities. The choices of all agents (households and firms) affect utility functions and production technologies. Showing by an example that basic assumptions are not enough to guarantee a regularity result in the space of initial endowments, we provide sufficient conditions for the regularity in the space of endowments and perturbations of the transformation functions
21
Scott, Heather Marie. "Parent Involvement in Children's Schooling: An Investigation of Measurement Equivalence across Ethnic Groups." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3339.
Анотація:
Epstein et al.'s Theory of Overlapping Spheres of Influence focuses on the interaction and communication, or partnerships, among families, schools, and the community to bring the three closer together. The theory works in conjunction with Epstein's typology of parental involvement, which focuses on six types of involvement that are instrumental to a child's development and his/her school and educational success. These serve as the framework for the study and support the construct of parent's involvement in children's schooling.
The purpose of the current study was to conduct further validation analyses of an inventory designed to measure the construct of parent involvement in their children's schooling through the investigation of measurement invariance to determine if the measurement properties of the inventory varied by race/ethnicity. The study compared the responses of 126 Hispanic parents/guardians with 116 White/non-Hispanic parents/guardians to investigate if these two groups were interpreting the items on the inventory in the same manner. The inventory was administered to a sample of parents/guardians of children in grades 3 through 5 in a local school district.
Findings indicated that the measurement model was misspecified for the White/non-Hispanic group and the Hispanic group and further measurement invariance testing was not conducted. Exploratory factor analyses were conducted in order to investigate which models would best fit the data for both groups. Feedback also was obtained from parents/guardians about the clarity of the inventory, which revealed their confusion with the response scale and the wording of particular items. In addition, they supplied issues or aspects of parent involvement that they found important but missing from the inventory. Results from the psychometric analyses and qualitative feedback indicated that the inventory requires modification and further psychometric investigation. In addition, caution should be exercised for anyone who may be considering utilizing the inventory. Results of the study were interpreted in terms of contributions to the parent involvement literature, as well as recommendations for the improvement of the inventory.
22
Galo, Nadya Regina. "Proposta de modelo de decisão para avaliação de fornecedores baseado no ELECTRE TRI para categorização e na teoria dos conjuntos fuzzy para a modelagem da incerteza e hesitação de múltiplos tomadores de decisão." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18156/tde-16072018-105923/.
Анотація:
A gestão eficaz dos processos que envolvem os fornecedores tem grande influência na melhoria do desempenho organizacional, sendo, portanto, fundamental para desenvolver capacidades das operações de produção que podem gerar vantagem competitiva, tais como qualidade, preço e tempo de entrega. A gestão de fornecedores inclui as atividades de qualificação, seleção, avaliação e desenvolvimento de fornecedores, além da alocação de pedido quando múltiplas fontes de fornecimento são selecionadas. A qualificação é um processo importante para assegurar que os fornecedores atendam requisitos mínimos de desempenho e, idealmente, deve ser realizada com métodos não compensatórios de categorização das alternativas. Entretanto, na literatura há poucos estudos que abordam a qualificação de fornecedores. Dentre aqueles que abordam, a maioria utiliza técnicas multicritério que são compensatórias e de ordenação. Outros aspectos importantes da gestão de fornecedores é a possível presença vários tomadores de decisão, caracterizando um processo de tomada de decisão em grupo, além da subjetividade de alguns critérios que gera incerteza nos julgamentos e hesitação. Ao se considerar essas questões na gestão de fornecedores, nenhuma pesquisa na literatura apresenta uma abordagem que contemple todos as características simultaneamente. Além disso, poucas pesquisas abordam os processos da gestão de fornecedores sob uma perspectiva integrada. Com vista a estas lacunas, esta pesquisa tem por objetivo a proposição de dois modelos de decisão que consideram os processos de qualificação, seleção e avaliação de fornecedores, em um cenário de tomada de decisão em grupo, considerando a incerteza e hesitação. Os modelos propostos têm por finalidade elicitar as preferências, agregar os julgamentos e categorizar os fornecedores. O primeiro modelo utiliza a representação linguística Triangular Hesitant Fuzzy Sets, para lidar com a hesitação nos julgamentos dos tomadores de decisão, além da técnica ELECTRE TRI para a categorização dos fornecedores. O segundo modelo se baseia na aplicação representação linguística Intuitionistic Fuzzy Sets para modelar a hesitação na parametrização das variáveis linguísticas e no ELECTRE TRI para a categorização. A elicitação é realizada com o uso do Fuzzy Delphi combinado com operadores de agregação do Triangular Hesitant Fuzzy Sets e Intuitionistic Fuzzy Sets. Os modelos de decisão foram detalhados e implementados no Matlab©. Após a proposição dos métodos, dois casos ilustrativos, obtidos a partir da coleta em campo, foram apresentados para analisar o desempenho dos modelos. Os casos ilustrativos mostraram resultados de categorização consistentes, especialmente para o procedimento pessimista do ELECTRE TRI. Testes com a hesitação nos julgamentos dos tomadores de decisão evidenciaram a importância da modelagem da hesitação, pois ela tem o potencial de alterar a categorização das alternativas. Testes com os parâmetros do ELECTRE TRI, confirmaram o efeito não compensatório da técnica e que a variação do nível de corte tem o potencial de tornar a categorização mais flexível. Assim, esta tese apresenta uma revisão de literatura sobre os processos de gestão de fornecedores e sobre tomada de decisão multicritério e em grupo, a proposição de métodos de apoio à tomada de decisão, casos ilustrativos para ilustrar o modelo, análises de sensibilidade dos métodos, além das conclusões e propostas para trabalhos futuros.Effective management of the processes that involving suppliers has a major influence on improving organizational performance and is therefore fundamental to develop production operations capabilities that can generate competitive advantage, such as quality, price and delivery time. Supplier management includes qualification, selection, evaluation and development of suppliers, as well as allocation of orders when multiple sources of supply are selected. Qualification is an important process to ensure that suppliers meet minimum performance requirements and ideally must be performed with non-compensatory methods of categorization. However, in the literature there are few studies that consider the process of supplier qualification. Among the studies that consider the qualification, most use multicriteria techniques that are compensatory and for ranking. Other important aspects of supplier management are the possible presence of several decision makers, characterizing a process of group decision making, as well as the subjectivity of some criteria that generates uncertainty in judgments and hesitation. When considering these issues in supplier management, none of the studies found in the literature presents an approach that contemplates all features simultaneously. In addition, few researches deal with supplier management processes from an integrated perspective. In view of these gaps, this research aims to propose two decision models that consider the processes of qualification, selection and evaluation of suppliers, in a scenario of group decision making, considering the uncertainty and hesitation. The proposed models have the purpose the elicitation of the preferences, the aggregation of the judgments and the categorization of the suppliers. The first model uses the linguistic representation Triangular Hesitant Fuzzy Sets, to deal with the hesitation in the judgments of the decision makers, in addition to the ELECTRE TRI technique for the categorization of the suppliers. The second model is based on the application of the linguistic representation Intuitionistic Fuzzy Sets to model the hesitation in the parameterization of the linguistic variables and in the ELECTRE TRI for categorization. Elicitation is performed with the use of Fuzzy Delphi combined with aggregation operators of the Triangular Hesitant Fuzzy Sets and Intuitionistic Fuzzy Sets. The decision models were detailed and implemented in Matlab©. Two illustrative cases, obtained from the field collection, were presented to analyze the performance of the models. The illustrative cases showed consistent categorization results, especially for the pessimistic procedure of ELECTRE TRI. Tests with hesitation in the judgments of decision makers highlighted the importance of modeling hesitation, since it has the potential to change the categorization of alternatives. Tests with the ELECTRE TRI parameters confirmed the non-compensatory effect of the technique and that the variation of the cut level has the potential to make categorization more flexible. Thus, this thesis presents a review of the literature on supplier management processes and on multicriteria and group decision making, the proposition of methods to support decision making, illustrative cases to illustrate the model, method sensitivity analyzes, besides the conclusions and proposals for future works.
23
Maku, Vyambwera Sibaliwe. "Mathematical modeling of TB disease dynamics in a crowded population." University of the Western Cape, 2020. http://hdl.handle.net/11394/7357.
Анотація:
Philosophiae Doctor - PhDTuberculosis is a bacterial infection which is a major cause of death worldwide. TB is a curable disease, however the bacterium can become resistant to the first line treatment against the disease. This leads to a disease called drug resistant TB that is difficult and expensive to treat. It is well-known that TB disease thrives in communities in overcrowded environments with poor ventilation, weak nutrition, inadequate or inaccessible medical care, etc, such as in some prisons or some refugee camps. In particular, the World Health Organization discovered that a number of prisoners come from socio-economic disadvantaged population where the burden of TB disease may be already high and access to medical care may be limited. In this dissertation we propose compartmental models of systems of differential equations to describe the population dynamics of TB disease under conditions of crowding. Such models can be used to make quantitative projections of TB prevalence and to measure the effect of interventions. Indeed we apply these models to specific regions and for specific purposes. The models are more widely applicable, however in this dissertation we calibrate and apply the models to prison populations.
24
Zou, Yuanyuan. "The Effects of Parceling on Testing Group Differences in Second-Order CFA Models: A Comparison between Multi-Group CFA and MIMIC Models." 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-850.
Анотація:
Using multi-group confirmatory factor analysis (MCFA) and multiple-indicator-multiple-cause (MIMIC) to investigate group difference in the context of the second-order factor model with either the unparceled or parceled data had never been thoroughly examined. The present study investigated (1) the difference of MCFA and MIMIC in terms of Type I error rate and power when testing the mean difference of the higher-order latent factor (delta kappa) in a second-order confirmatory factor analysis (CFA) model; and (2) the impact of data parceling on the test of (delta kappa) between groups by using the two approaches. The methods were introduced, including the design of the models, the design of Monte Carlo simulation, the calculation of empirical Type I Error and empirical power, the two parceling strategies, and the adjustment of the random error variance.
The results suggested that MCFA should be favored when the compared groups were when the different group sizes were paired with the different generalized variances, and MIMIC should be favored when the groups were balanced (i.e., have equal group sizes) in social science and education disciplines. This study also provided the evidence that parceling could improve the power for both MCFA and MIMIC when the factor loadings were low without bringing bias into the solution when the first-order factors were collapsed. However, parceling strategies might not be necessary when the factor loadings were high. The results also indicated that the two approaches were equally favored when domain representative parceling strategy was applied.
25
Huang, Shih-Pu, and 黃世溥. "Group Sequential Comparison for Linear Mixed Models with Polynomial Trend in Multi-Armed Trials." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/78366312494520623221.
Анотація:
碩士淡江大學
統計學系碩士班
97
For ethical, economical and administrative considerations, group sequential methods are frequently applied for possibly early determination clinical trials. For cross-sectional data, three common group sequential methods for comparing means between two treatments are proposed by Pocock (1977), O''Brien and Fleming (1979) and Lan and DeMets (1983). For longitudinal data, Lee and DeMets (1991) proposed a sequential comparison for testing the rates of change with linear trend between two treatments. In this article, a group sequential method for multi-armed trials is proposed, which is a generalization of Lee and DeMets'' method, for testing responses changes with time in polynomial trend. The asymptotic joint distribution of proposed test statistics is a multivariate chi-squared distribution. Boundaries of the proposed methods based on Pocock-type and O''Brien and Fleming-type are provided for practical use. The proposed testing procedure is illustrated by a clinical example.
26
Bose, Biswajit, Xiaogang Wang, and Eric Grimson. "Detecting and tracking multiple interacting objects without class-specific models." 2006. http://hdl.handle.net/1721.1/32536.
Анотація:
We propose a framework for detecting and tracking multiple interacting objects from a single, static, uncalibrated camera. The number of objects is variable and unknown, and object-class-specific models are not available. We use background subtraction results as measurements for object detection and tracking. Given these constraints, the main challenge is to associate pixel measurements with (possibly interacting) object targets. We first track clusters of pixels, and note when they merge or split. We then build an inference graph, representing relations between the tracked clusters. Using this graph and a generic object model based on spatial connectedness and coherent motion, we label the tracked clusters as whole objects, fragments of objects or groups of interacting objects. The outputs of our algorithm are entire tracks of objects, which may include corresponding tracks from groups of objects during interactions. Experimental results on multiple video sequences are shown.
27
Darbyshire, Paul. "Modeling Group Communication in a Complex System for Achieving Group Goals." Thesis, 2013. https://vuir.vu.edu.au/25840/.
Анотація:
This thesis investigates the effect of communication as a function of time on a
multi-agent simulation based on a military distillation utilizing reinforcement learning
for a group of agents. The original contribution to knowledge is a new model of
cooperative learning developed as an enhanced Q-learning update function which also
includes learning events communicated by other agents. Further contributions lie in the
detailed analysis of simulation results establishing evidence of the cause-effect
relationship between communication and improved performance. The improvement in
performance is visualized by utilizing surface plot diagrams of the agents state-action
matrix. These diagrams show the how group communications reinforce effective
actions for the agents at an early stage in the simulation.
28
Greenlaw, Keelin. "A Bayesian Group Sparse Multi-Task Regression Model for Imaging Genomics." Thesis, 2015. http://hdl.handle.net/1828/6577.
Анотація:
Recent advances in technology for brain imaging and high-throughput genotyping have motivated studies examining the influence of genetic variation on brain structure. In this setting, high-dimensional regression for multi-SNP association analysis is challenging as the brain imaging phenotypes are multivariate and there is a desire to incorporate a biological group structure among SNPs based on their belonging genes. Wang et al. (Bioinformatics, 2012) have recently developed an approach for simultaneous estimation and SNP selection based on penalized regression with regularization based on a novel group l_{2,1}-norm penalty, which encourages sparsity at the gene level. A problem with the proposed approach is that it only provides a point estimate. We solve this problem by developing a corresponding Bayesian formulation based on a three-level hierarchical model that allows for full posterior inference using Gibbs sampling. For the selection of tuning parameters, we consider techniques based on: (i) a fully Bayes approach with hyperpriors, (ii) empirical Bayes with implementation based on a Monte Carlo EM algorithm, and (iii) cross-validation (CV). When the number of SNPs is greater than the number of observations we find that both the fully Bayes and empirical Bayes approaches overestimate the tuning parameters, leading to overshrinkage of regression coefficients. To understand this problem we derive an approximation to the marginal likelihood and investigate its shape under different settings. Our investigation sheds some light on the problem and suggests the use of cross-validation or its approximation with WAIC (Watanabe, 2010) when the number of SNPs is relatively large. Properties of our Gibbs-WAIC approach are investigated using a simulation study and we apply the methodology to a large dataset collected as part of the Alzheimer's Disease Neuroimaging Initiative.Graduate
29
HSU, HSIN-HUI, and 徐心蕙. "The Research of Customer Loyalty Model of Taroko Gorge in 2017 and 2018 with Multi-Group Comparison." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/yeu2vv.
Анотація:
碩士大仁科技大學
休閒事業管理研究所
106
The purpose of this study is to verify the measurement equivalence of the customer loyalty model of Taroko Park across multiple groups between 2017 and 2018, as well as to explore the relationship between corporate image, service quality, customer satisfaction, and customer loyalty of Taroko Park. Based on the analysis mentioned above, a specific strategie that is able to enhance the consumer loyalty of Taroko Park was propsed. In this study, a survey was conducted on the consumers of the Taroko Park: there were 308 valid samples in 2017 and 329 valid samples in 2018 respectively. SPSS 12.0 was utilized to perfom the data processing and descriptive statistics, and AMOS 20.0 was used to do the structural equation model (SEM) analysis of samples across varied years. Thus we can verify the validity of the study models of the two groups of samples by using Multi-group analysis. Results were obtained as follows: (1) The service quality of Taroko Park significantly affected the satisfaction. (2) Satisfaction of Taroko Park significantly affected loyalty. (3) Corporate image of Taroko Park significantly affects loyalty. (4) The loyalty model of Taroko Park between 2017 and 2018 was met for measurement equivalence. Based on the results mentioned above, specific suggestion for enhancing customer loyalty by enhancing corporate image, service quality and satisfaction are proposed: (a) Increase the exposur frequency of corporate image advertisements through. (b) Holding charity activities. (c) make good use of the power of the Internet. (d) more configuration rest space. (e) Improve service facilities and parking space. (f) improve the space marking.
30
HUANG, YU-HSUAN, and 黃雨璇. "The Research Of Customer Loyalty Model Of E-DA WORLD In 2017 And 2018 With Multi-group Comparison." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3wwgzn.
Анотація:
碩士大仁科技大學
休閒事業管理研究所
106
The purpose of this research aim to explore customer loyalty model of E-DA WORLD. The sampling questionnaire for consumers was for April 2017 and April 2018 sample of 350 Consumers at E-DA WORLD.In April 2017,total 350 questionnaires were handed out which, 327 questionnaires were effective,giving a recycling rate of 93.43 %. In April 2018,total 350 questionnaires were handed out which, 325 questionnaires were effective,giving a recycling rate of 92.86 %. A total of 652 valid questionnaires in two years. The research method adopts statistical software Amos 21.0 to analyze the SEM model.Results:1. Corporate image, switching cost and customer satisfaction have a significant affect customer loyalty.2. Service quality have a significant affect on customer satisfaction.3. Corporate image have not a significant affect on customer satisfaction in 2017, corporate image have a significant affect on customer satisfaction in 2018.4. Customer loyalty model of E-DA WORLD has Measurement Equivalence in 2017 and 2018.According the results,this study shows following suggests:1. Well-designed circulation planning for direct consumption at the counter.2. Effectively deal with app issues to enhance customer satisfaction.3. Enhance corporate exposure to increase corporate profits.4. Hire staff with language expertise to grab international tourists.5. Strengthen staff training and enhance overall morale.6. Provide consumers with creative goods and services.
31
Yen, Ming-Fang, and 嚴明芳. "A Markov chain model to assess a multi-centered screening project for breast cancer in Taiwan － high risk group approach." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/10799581791652764527.
32
Tsai, Han-Chung, and 蔡漢忠. "A Study on Multi-Group Analysis of Behavioral Model in the Fan Page of Jeremy Lin between 2014 and 2015." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/31381657329362611218.
Анотація:
碩士大仁科技大學
休閒事業管理研究所
103
The purpose of the multi-group study was to apply Technology Acceptance Model (TAM) and Structural Equation Modeling (SEM) to analyze behavioral model in the Fan Page of Jeremy Lin between 2014 and 2015. The study subjects that joined the fan page of Jeremy Lin were chosen by using convenience sampling from the website, YouthWant. To explore the model fit between sample covariance matrix and model covariance matrix, the study analyzed the behavioral model in the Fan Page of Jeremy Lin; in addition, the multi-group analysis was also applied in the study to discuss the relation to various factors and analyze the measurement invariance of behavioral model in Fan Page of Jeremy Lin between 2014 and 2015. According to the data analysis, the results showed that “ perceived ease of use on perceived usefulness,” “perceived ease of use on attitude,” “attitude on behavioral intention,” “perceived usefulness on attitude,” and “ perceived usefulness on behavioral intention” were significantly different. The researcher suggested that the fan page should catch users’ first sight, increase the specifics, and make it easy to use. As to the contents of the fan page, variablity was also necessary. Besides, soliciting nice articles, designing some interesting activities for users and understanding users’ need were helpful to increase their motivation to surf the fan page more often. Furthermore, enhancing the interaction and entertainment and creating a friendly fan page environment could raise and reinforce users’ interest in the fan page. Keywords: Technology Acceptance Model, Jeremy Lin, Fan Page, Multi-Group Analysis
33
Justice, Morgan. "Social Support and Mental Health Among Homeless Youth: A Multi-Group SEM Model of Non-LGBT*, LGB, and Trans* Youth in Metro-Atlanta." 2016. http://scholarworks.gsu.edu/sociology_theses/60.
Анотація:
LGBT* youth are over-represented among homeless youth and they face unique circumstances from their non-LGBT* homeless peers, such as increased risks of psychological distress (Fredriksen-Goldsen et al. 2014). Through multi-group, structural equation modeling, I compare the effects of time homeless on mental health outcomes (e.g., psychological distress) as measured by the Kessler 6 (K6) scale mediated by social support across non-LGBT*, LGB, and trans* groups. Findings indicate that social support is a significant mediator between the time a youth is homeless and their mental health outcomes, regardless of LGBT* status. Youth who are homeless six months or longer have worse mental health and fewer social supports than youth who are homeless less than six months. Additionally, the more social support a youth has, the higher their mental health is; however, individuals assigned female at birth have fewer social supports than males.
34
Teques, Pedro Humberto Araújo. "Envolvimento parental no desporto." Doctoral thesis, 2015. http://hdl.handle.net/10400.5/11565.
Анотація:
O presente conjunto de investigações pretendeu estudar o envolvimento parental na competição desportiva de crianças e jovens. Baseado no modelo do envolvimento parental no desporto (Teques & Serpa, 2009), o estudo permitiu concretizar dois objectivos fundamentais. Primeiro, desenvolver um conjunto de escalas válidas e fidedignas para aceder aos constructos incluídos no modelo teórico. Segundo, testar as hipóteses fundamentadas na estrutura conceptual do modelo com o propósito de compreender (1) a razão porque os pais se envolvem no desporto dos filhos, (2) quais os comportamentos utilizados pelos pais durante o envolvimento, e (3) como é que o envolvimento influencia o contexto de realização do jovem atleta. No total, participaram voluntariamente 1620 pais e 1665 jovens atletas de vários desportos individuais e coletivos, com idades compreendidas entre os 9 e os 18 anos. A prossecução dos objectivos teve por base uma série de três estudos independentes. Os resultados do primeiro estudo sugerem que as crenças do papel parental, a auto-eficácia, a perceção das invocações oriundas do treinador e do jovem atleta, o tempo e energia disponíveis, e os conhecimentos e competências relacionam-se com as atividades de envolvimento dos pais. No segundo estudo, os resultados demonstraram que as perceções dos comportamentos parentais de encorajamento, reforço, instrução, e modelagem medeiam a relação entre os comportamentos reportados pelos pais e as variáveis psicológicas de auto-eficácia, auto-eficácia social, motivação intrínseca, e estratégias de autorregulação dos jovens. Os resultados do terceiro estudo indicam que as perceções dos comportamentos dos pais relacionam-se com a realização desportiva através dos efeitos de mediação da auto-eficácia, autoeficácia social e das estratégias de autorregulação. Implicações para a intervenção, limitações e direções futuras para a investigação são também discutidas.The present investigation focused on parental involvement in youth competitive sport. Based on the model of parental involvement in sport (Teques & Serpa, 2009), the study was designed to accomplish two major goals. The first was to develop valid and reliable measures for assessing constructs included in the model. The second was to test model-driven hypotheses about the relationships between the variables of the model with the purpose to examine (1) the reason parents decide to become involved in youth sport, (2) the mechanisms they use during their involvement, and (3) how their involvement influence youth achievement in sport. In total, 1620 parents and 1665 youth athletes, aged between 9 and 18 years from various competitive sports, volunteered for the study. The investigation was completed in a series of three independent studies. In the first study, a structural equation model demonstrated that the parental role beliefs, parental self-efficacy, perceptions of child and coach invitations, self-perceived time and energy, and knowledge and skills predicted parents’ involvement activities. In the second study, results supported the hypothesized model in which athletes’ perceptions of parents’ encouragement, reinforcement, instruction, and modelling mediated the relationship between parents’ reported behaviors and the athletes’ self-efficacy, social self-efficacy, intrinsic motivation, and self-regulation. The results of the third study revealed that perceptions of parenting practices appear to be related to both motivational and self-regulated behaviours, which, in turn, were associated with youth achievement in sport. Implications for the practice, limitations and future directions for the research are discussed.
35
Islam, Rubaiyat. "Theory and Applications of Microstrip/Negative-refractive-index Transmission Line (MS/NRI-TL) Coupled-line Couplers." Thesis, 2011. http://hdl.handle.net/1807/31789.
Анотація:
The electromagnetic coupling of a microstrip transmission line (MS-TL) to a metamaterial backward wave Negative-Refractive-Index transmission line (NRI-TL) is the primary investigation of this dissertation. The coupling of forward waves in the MS-TL to the backward waves in the NRI-TL results in the formation of complex modes, characterized by simultaneous phase progression and attenuation along the lossless lines.
Through network-theoretic considerations, we investigate the properties of these modes in the complex-frequency plane of the Laplace domain to help unravel the confusion that has existed in the literature regarding the independent excitation of a pair of conjugate complex modes. We show that it is possible to arbitrarily suppress one of the modes over a finite bandwidth and completely eliminate it at a discrete set of frequencies using proper source and load impedances. Hence we use conjugate modes with independent amplitudes in our eigenmode expansion when we analyse various coupling configurations between the two types of lines (MS/NRI-TL coupler).
We derive approximate closed-form expression for the scattering parameters of the MS/NRI-TL coupler and these are complemented by design charts that allow the synthesis of a wide range of specifications. Moreover, these expressions reveal that such couplers allow for arbitrary backward coupling levels along with very high-isolation when they are made half a guided wavelength long. The MS/NRI-TL coupler offers some interesting applications which we highlight through the design and testing of a 3-dB power splitter, a high-directivity signal monitor and a compact corporate power divider. We have included design, simulation and experimental data for the fabricated prototypes exhibiting good agreement and thereby justifying the theory that has been developed in this work to explain the coupling between a right-handed MS-TL and a left-handed NRI-TL.