Dissertations / Theses on the topic 'Searching behavior – Mathematical models'
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Oleś, Katarzyna A. "Searching for the optimal control strategy of epidemics spreading on different types of networks." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21199.
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The main goal of my studies has been to search for the optimal control strategy of controlling epidemics when taking into account both economical and social costs of the disease. Three control scenarios emerge with treating the whole population (global strategy, GS), treating a small number of individuals in a well-defined neighbourhood of a detected case (local strategy, LS) and allowing the disease to spread unchecked (null strategy, NS). The choice of the optimal strategy is governed mainly by a relative cost of palliative and preventive treatments. Although the properties of the pathogen might not be known in advance for emerging diseases, the prediction of the optimal strategy can be made based on economic analysis only. The details of the local strategy and in particular the size of the optimal treatment neighbourhood weakly depends on disease infectivity but strongly depends on other epidemiological factors (rate of occurring the symptoms, spontaneously recovery). The required extent of prevention is proportional to the size of the infection neighbourhood, but this relationship depends on time till detection and time till treatment in a non-nonlinear (power) law. The spontaneous recovery also affects the choice of the control strategy. I have extended my results to two contrasting and yet complementary models, in which individuals that have been through the disease can either be treated or not. Whether the removed individuals (i.e., those who have been through the disease but then spontaneously recover or die) are part of the treatment plan depends on the type of the disease agent. The key factor in choosing the right model is whether it is possible - and desirable - to distinguish such individuals from those who are susceptible. If the removed class is identified with dead individuals, the distinction is very clear. However, if the removal means recovery and immunity, it might not be possible to identify those who are immune. The models are similar in their epidemiological part, but differ in how the removed/recovered individuals are treated. The differences in models affect choice of the strategy only for very cheap treatment and slow spreading disease. However for the combinations of parameters that are important from the epidemiological perspective (high infectiousness and expensive treatment) the models give similar results. Moreover, even where the choice of the strategy is different, the total cost spent on controlling the epidemic is very similar for both models. Although regular and small-world networks capture some aspects of the structure of real networks of contacts between people, animals or plants, they do not include the effect of clustering noted in many real-life applications. The use of random clustered networks in epidemiological modelling takes an impor- tant step towards application of the modelling framework to realistic systems. Network topology and in particular clustering also affects the applicability of the control strategy.
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Stocco, Aaron B. "Predicting Democratic Peace (DP) Breakdown, a new game-theoretic model of democratic crisis behavior." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0023/MQ50575.pdf.
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Oh, Joung Hoon. "Behavior of an ion in a bubble in the ground state." PDXScholar, 1991. https://pdxscholar.library.pdx.edu/open_access_etds/4193.
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Deuterons might be trapped in a bubble embryo which occur s due to statistical fluctuation in heavy water. The size of the bubble embryo is expected to be an order of a small molecule. The ground state energy level which the deuteron may occupy in the bubble is calculated by solving the Schroedinger equation, and by considering the interaction between the trapped deuteron by a spherical bubble and the surrounding polarized liquid medium (heavy water). From the dependence of the energy eigenvalue of the ground state on the bubble radius, the pressure exerted on the bubble wall is obtained. It is found that the pressure is negatively very large if the bubble radius is about the molecular size (3 to 7 Å). From extrapolating this result to larger sizes, we expect that a bubble would quickly collapse if enough energy is supplied and never grows to a stable bubble when the deuteron is trapped in the ground state.
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Mtundu, Nangantani Davies Godfrey. "The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models." PDXScholar, 1987. https://pdxscholar.library.pdx.edu/open_access_etds/527.
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The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture.
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Chang, Kwangpil. "Essays on heterogeneity in choice modeling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34537.pdf.
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TONELLATO, PETER JOHN. "CRITICAL BEHAVIOR OF AN IGNITION MODEL IN CHEMICAL COMBUSTION." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188056.
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A model for the hot slab ignition problem is analyzed to determine critical conditions based on the parameters of the system. Activation energy asymptotics, a singular perturbation approach, is applied to the governing equation resulting in a Volterra integral equation of the second kind whose solution represents the temperature perturbation at the surface of the hot slab. The system is said to be supercritical for given parameter values when the temperature perturbation blows up in small finite time, an indication of ignition, or subcritical when the blow up time is large, indicating that heat loss effects overcome the hot slab ignition mechanisms. Comparison principles for integral equations are used to construct upper and lower solutions of the equation. The exact solution as well as the upper and lower solutions depend on two parameters ε, the Zeldovich number a measure of the heat release and λ, the scaled hot slab size. Upper and lower bounds on the transition region, delineating the super-critical from the sub-critical region, are derived based upon the lower and upper solution behavior. The product integration method is used to compute solutions of the Volterra equation for values of ε and λ in the transition region. The computations indicate that a critical curve, λ(c) lying between the analytic bounds, exists.
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Mao, Wen. "Essays on bargaining theory and voting behavior." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/38561.
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Alegre, Sanahuja Juan. "Mathematical network models applied to the analysis of mobile applications behavior." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/67389.
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[EN] The network topologies are present in different social, political, economic and technological phenomena. These network structures allow to share information, alliances generation, behavior influence, opinion spread and virus transmission, among other aspects.
Online networks are a reflection of the offline world and they also show these kind of network structures, in such a way that they allow the information transmission, social circle or community detection, affinity prediction between individuals, generation of recommendations, detection of influence people and generation of viral phenomena. Although all of these networks exhibit heterogeneity, they have enough underlying structure to allow their modelization for the study and analysis of all the listed phenomena.
Nowadays, the line between the offline world and the online world is becoming more diffuse and there are network structures where both natures are mixed: There are almost as many mobile phones as individuals and in developed societies, the pervasiveness of smartphones on day-to-day is unquestionable in such a way that almost everybody is almost always connected everywhere. This permanent connection means that the individual, simultaneously and in a continuous mode, is a node belonging to its social network and its social network online.
A key aspect of smartphones are the mobile applications that can be downloaded to the device. There are many applications for a host of different uses and the user behavior with these applications is the factor that determines how these applications behave. Also, mobile applications are the main source of infection of viruses on smartphones and, in this case, also the user behavior is what determines the transmission of these viruses. That is, the number of downloads of the application, the retention time of the application without being uninstalled, weekly minutes of usage, the popularity of the application, the transmission of viruses between smartphones, etc., depend on user behavior and, since the user is part of a social "offline" network and a social online network, in which the information is shared, communities are generated, behavior is influenced, opinion is spread and viruses are transmitted, we can intuit that the application behaviors can be modeled considering the network structure which user belongs to, so it is possible to analyze and study issues such as predicting the retention and download of applications and/or the transmission of viruses between smartphones.
The purpose of this thesis is to analyze the behavior of mobile applications through mathematical network models. The behavior of mobile applications will be defined by the network of the users, taking into account parameters such as user behavior and technical issues of the mobile devices, so for model the networks both factors will be taken into account.[ES] Las estructuras de redes están presentes en multitud de fenómenos sociales, políticos, económicos y tecnológicos. Estas estructuras permiten compartir información, constituir alianzas, influir en comportamientos, generar corrientes de opinión, y transmitir virus, entre otros aspectos. Las redes online son un reflejo del mundo "analógico" y también presentan este tipo de estructura de red, de tal forma que permiten transmitir información, detectar comunidades, predecir afinidades entre individuos, generar recomendaciones, identificar individuos influyentes o producir fenómenos virales. Aunque todas estas redes son de naturaleza heterogénea, la estructura subyacente que presentan permiten su modelización para el estudio y análisis de los fenómenos indicados. Actualmente, la línea que divide el mundo "analógico" y el mundo online es cada vez más difusa produciéndose estructuras de redes donde se entremezclan ambas naturalezas: Existen casi tantos teléfonos móviles como individuos y, en las sociedades desarrolladas, la omnipresencia de los smartphones en el día día es incuestionable de tal forma que cualquier persona está conectada casi en todo momento y lugar. Esta conexión permanente conlleva que el individuo constituya simultáneamente y de un modo continuo un nodo de su estructura de red social y de su red social online. Una parte fundamental de los smartphones son las aplicaciones que se pueden descargar en el dispositivo. Existen multitud de aplicaciones para infinidad de utilidades distintas y el comportamiento del usuario frente a esas aplicaciones es el que determina cómo se comportan dichas aplicaciones. Asimismo, las aplicaciones móviles son la principal fuente de contagio de virus en los smartphones y en este caso, también el comportamiento del usuario es el que determina la transmisión de esos virus. Es decir, el número de descargas de la aplicación, el tiempo de retención de la aplicación sin ser desinstalada, los minutos semanales de uso, la popularidad de la aplicación, la transmisión de virus en smartphones, etc., dependen del comportamiento del usuario y, puesto que el usuario forma parte de una red social "offline" y una red social online, en las cuales se comparte y transmite información, se constituyen comunidades, se influye en los comportamientos, se generan corrientes de opinión y se transmiten virus, podemos intuir que los comportamientos de las aplicaciones pueden ser modelizados considerando la estructura de red de la que el usuario forma parte, de tal forma que sea posible analizar y estudiar aspectos tales como predecir la descarga y retención de aplicaciones y/o la transmisión de virus entre smartphones. El propósito de la presente tesis doctoral es modelizar y analizar el comportamiento de las aplicaciones móviles mediante estructuras de red. El comportamiento de las aplicaciones móviles vendrá definido por la red formada por los usuarios, teniendo en cuenta tanto parámetros de comportamiento de los usuarios como parámetros relacionados con aspectos técnicos de los dispositivos móviles, por lo que para la modelización de las redes se tendrán en cuenta ambos factores.
[CAT] Les estructures de xarxes estàn presents en multitud de fenòmens socials, pol'itics, econòmics i tecnològics. Estes estructures permeten compartir informació, constituir aliances, influir en comportaments, generar corrents d'opinió, i transmetre virus, entre altres aspectes. Les xarxes online són un reflex del món analògic i també presenten este tipus d'estructura de xarxa, de tal forma que permet transmetre informació, detectar comunitats, predir afinitats entre individus, generar recomanacions, identificar individus influents o produir fenòmens virals. Encara que totes estes xarxes són de naturalesa heterogènia, l'estructura subjacent que presenten permeten la seua modelització per a l'estudi i anàlisi dels fenòmens indicats. Actualment, la línia que dividix el món analògic i el món online és cada vegada més difusa produintse estructures de xarxes on s'entremesclen ambós naturaleses: Existixen quasi tants telèfons mòbils com individus i, en les societats desenvolupades, l'omnipresència dels smartphones en el dia a dia és inqüestionable de tal forma que qualsevol persona està connectada quasi en tot moment i lloc. Esta connexió permanent comporta que l'individu constituïsca simultàniament i d'una manera contínua un node de la seua estructura de xarxa social i de la seua xarxa social online. Una part fonamental dels smartphones són les aplicacions que es poden descarregar en el dispositiu. Hi ha multitud d'aplicacions per a infinitat d'utilitats distintes i el comportament de l'usuari enfront d'eixes aplicacions és el que determina com es comporten aquestes aplicacions. Així mateix, les aplicacions mòbils són la principal font de contagi de virus en els smartphones i en este cas, també el comportament de l'usuari és el que determina la transmissió d'eixos virus. És a dir, el nombre de descàrregues de l'aplicació, el temps de retenció de l'aplicació sense ser esborrada, els minuts setmanals d'ús, la popularitat de l'aplicació, la transmissió de virus entre smartphones, etc., depenen del comportament de l'usuari i, ja que l'usuari forma part d'una xarxa social "offline" i una xarxa social online, en les quals es compartix i es transmet informació, es constituïxen comunitats, s'influïx en els comportaments, es generen corrents d'opinió i es transmeten virus, podem intuir que els comportaments de les aplicacions poden ser modelitzats considerant l'estructura de xarxa de què l'usuari forma part, de tal forma que siga possible analitzar i estudiar aspectes com ara predir la descàrrega i retenció d'aplicacions i/o la transmissió de virus entre smartphones. El propòsit de la present tesi doctoral és modelitzar i analitzar el comportament de les aplicacions mòbils per mitjà d'estructures de xarxa. El comportament de les aplicacions mòbils vindrà definit per la xarxa formada pels usuaris, tenint en compte tant paràmetres de comportament dels usuaris com paràmetres relacionats amb aspectes tècnics dels dispositius mòbils, per la qual cosa per a la modelització de les xarxes es tindràn en compte ambdós factors.
Alegre Sanahuja, J. (2016). Mathematical network models applied to the analysis of mobile applications behavior [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/67389
TESIS
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Goldberg, Ilfra Charlotte. "Why is there fast-track promotion?" Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56909.
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This thesis seeks an explanation for the existence of corporate "fast tracks". Part One surveys four existing fast track models from the literature. In tournament theory, fast tracks have been viewed as a response to the adverse selection problem. In models where the firm uses junior positions for on-the-job screening, they may be a possibility permitted by a particular technology. Alternatively, they may arise from the signalling engaged in by workers when there is asymmetric information. Finally, they can be used as a way of overcoming a lack of precise information on worker ability.In the second part of the thesis an alternative explanation is proposed. A firm is considered to consist of two levels: production workers and managerial workers. If a worker is an able manager, the firm will lose valuable production time by slow promotion. However, slower promotion allows more information to be revealed for a given expenditure. Different track lengths are created depending on the firm's initial assessment of managerial competence.
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Van, Zyl Verena Helen. "Searching for histogram patterns due to macroscopic fluctuations in financial time series." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/3078.
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Thesis (MComm (Business Management))--University of Stellenbosch, 2007.ENGLISH ABSTRACT: his study aims to investigate whether the phenomena found by Shnoll et al. when applying histogram pattern analysis techniques to stochastic processes from chemistry and physics are also present in financial time series, particularly exchange rate and index data. The phenomena are related to fine structure of non-smoothed frequency distributions drawn from statistically insufficient samples of changes and their patterns in time. Shnoll et al. use the notion of macroscopic fluctuations to explain the behaviour of sequences of histograms. Histogram patterns in time adhere to several laws that could not be detected when using time series analysis methods. In this study general approaches are reviewed that may be used to model financial markets and the volatility of price processes in particular. Special emphasis is placed on the modelling of highfrequency data sets and exchange rate data. Following previous studies of the Shnoll phenomena from other fields, different steps of the histogram sequence analysis are carried out to determine whether the findings of Shnoll et al. could also be applied to financial market data. The findings of this thesis widen the understanding of time varying volatility and can aid in financial risk measurement and management. Outcomes of the study include an investigation of time series characteristics in terms of the formation of discrete states, the detection of the near zone effect as proclaimed by Shnoll et al., the periodic recurrence of histogram shapes as well as the synchronous variation in data sets measured in the same time intervals.
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Gayley, Todd Warwick. "Genetic models of two-phenotype frequency-dependent selection." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184883.
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The aim of this study is to place a wide variety of two-phenotype frequency-dependent selection models into a unified population-genetic framework. This work is used to illuminate the possible genetic constraints that may exist in such models, and to address the question of evolutionary modification of these constraints. The first part of Chapter 1 synthesizes from the literature a general framework for applying a genetic structure to a simple class of two-phenotype models. It shows that genetic constraints may prevent the population from achieving a predicted phenotypic equilibrium, but the population will equilibrate at a point that is as close as possible to the phenotypic equilibrium. The second part of Chapter 1 goes on to ask whether evolutionary modification of the genetic system might be expected to remove these constraints. Chapter 2 provides an example of the application of the framework developed in Chapter 1. It presents re-analysis of a model for the evolution of social behavior by reciprocation (Brown et al. 1982). The genetic results of Chapter 1 apply to this model without modification. I show that Brown et al. were unnecessarily restrictive in their assumptions about the types of genetic systems that support their conclusions. Chapter 3 discusses some models for the evolution of altruism that do not fit the assumptions of Chapter 1, despite their two-phenotype structure. These models violate the fundamental assumption of Chapter 1, this being the way in which individual fitness is derived from the behavioral fitnesses. The first part is a complete, in-depth analysis of diploid sib-sib kin selection. I show that some results from the basic model can be used, provided the behavioral inclusive fitness functions are substituted for the true behavioral fitnesses. The second part is an analysis of the validity of the concept of behavioral structure, as introduced by Michod and Sanderson (1985). I show that this concept is flawed as a general principle. Chapter 4 extends the basic model to the case of sex-allocation evolution. I show how many of the central results of sex-allocation theory can be derived more simply using a two-phenotype framework.
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SOMASUNDARAM, SUJITHAN. "CONSTITUTIVE MODELLING FOR ANISOTROPIC HARDENING BEHAVIOR WITH APPLICATIONS TO COHESIONLESS SOILS (INDUCED, KINEMATIC, NON-ASSOCIATIVENESS)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/188165.
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A constitutive model based on rate-independent elastoplasticity concepts is developed to simulate the behavior of geologic materials under arbitrary three-dimensional stress paths, stress reversals and cyclic loading. The model accounts for the various factors such as friction, stress path, stress history, induced anisotropy and initial anisotropy that influence the behavior of geologic materials. A hierarchical approach is adapted whereby models of progressively increasing sophistication are developed from a basic isotropic-hardening associative model. The influence of the above factors is captured by modifying the basic model for anisotropic (kinematic) hardening and deviation from normality (nonassociativeness). Both anisotropic hardening and deviation from normality are incorporated by introducing into the formulation a second order tensor whose evolution is governed by the level of induced anisotropy in the material. In the stress-space this formulation may be interpreted as a translating potential surface Q that moves in a fixed field of isotropic yield surfaces. The location of the translating surface in the stress-space, at any stage of the deformation, is given by the 'induced anisotropy' tensor. A measure to represent the level of induced anisotropy in the material is defined. The validity of this representation is investigated based on a series of special stress path tests in the cubical triaxial device on samples of Leighton Buzzard sand. The significant parameters of the models are defined and determined for three sands based on results of conventional laboratory test results. The model is verified with respect to laboratory multiaxial test data under various paths of loading, unloading, reloading and cyclic loading.
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Ng, Desmond. "Micro-economic evolution of the firm : an organizational ecology perspective." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27383.
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Selection and adaptation paradigms have been jointly employed in the derivation of a theoretical model of firm evolution. This construct enabled researchers to explore: "why are there so many different kinds of organizations?". In that, evolutionary influences and adaptive firm behaviour were simultaneous forces that shape the survival of organizational forms over time. Such a notion was applied towards a dynamic programming context. This dynamic programming model was translated into a computer simulation such that an empirical representation of firm evolution was depicted.The results from four computer simulations confirmed the selection and adaptation propositions described in this research. The simulations found evolutionary forces to be significant determinants to differentiating firm survival. While, adaptive firm behaviour only served to prolong organizational survivability with in the confines of the selection forces of the market.
Future organizational research should focus on expanding the dimensions of strategic adaptation, strategic, voluntarism, niche width dynamics, organizational inertia theory and organizational slack. By addressing these areas, a more comprehensive depiction of organizational evolution could be attained.
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Ho, Yeu Chuan. "Stability and elastohydrodynamic behavior of rotary lip seals." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185433.
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Mathematical models for rotary lip seals is developed to study the basic stability and dynamic response of the lip seals. In this thesis, a linear stability analysis is performed to find the stability characteristics of such a mechanical system. Then, a finite element algorithm for the numerical integration of the system of coupled differential equations governing the dynamic behavior of the lip seals is presented.
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Freedland, Graham. "Investigation of Jet Dynamics in Cross-Flow: Quantifying Volcanic Plume Behavior." PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/3314.
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Volcanic eruption columns inject high concentrations of ash into the atmosphere. Some of this ash is carried downwind forming ash clouds in the atmosphere that are hazardous for private and commercial aviation. Current models rely on inputs such as plume height, duration, eruption rate, and meteorological wind fields. Eruption rate is estimated from plume height using relations that depend on the rate of air entrainment into the plume, which is not well quantified. A wind tunnel experiment has been designed to investigate these models by injecting a vertical air jet into a cross-flow. The ratio of the cross-flow and jet velocities is varied to simulate a weak plume, and flow response is measured using particle image velocimetry. The plumes are characterized and flow data relative to the centerline is examined to measure the growth of weak plumes and the entrainment velocity along its trajectory. It was found that cross-flow recirculates behind the jet and entrainment occurs both up and downstream of the jet. Analysis of the generation of turbulence enhanced results by identifying the transition point to bending plume and the growth of the shear layer in a bending plume. This provides information that can be used to improve models of volcanic ash concentration changes in the atmosphere.
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Ozturk, Hande Isik. "Parametric Study On Selected Mathematical Models For Dynamic Creep Behavior Of Asphalt Concrete." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609023/index.pdf.
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Rut formation has long been recognized as a distress mechanism in flexible pavements. One of the causes of rut formation in flexible pavements is permanent deformation of uppermost asphalt concrete layers due to repeatedly applied traffic loading. The long term permanent deformation of asphalt concrete under repeated load is commonly called as dynamic creep. The primary objective of this thesis is to examine dynamic creep behavior of asphalt concrete specimens tested in laboratory and also study some suitable mathematical models for representing dynamic creep behavior.
In this study, a set of uniaxial repeated load creep tests were performed on standard Marshall specimens prepared at three different bitumen contents. The effects of bitumen content and test condition parameters on dynamic creep behavior are examined. Among several mathematical creep models suggested by researchers, two well known models and a model proposed by the author are selected for representing the laboratory creep behavior. For each of these models, the interactions of the model parameters with varying bitumen content and test conditions are studied to detect probable definite trends, and to evaluate whether some relations for the model parameters as functions of bitumen content and test conditions can be developed or not.
The results of analyses showed that all three mathematical models used in this study are successful in representing the laboratory dynamic creep behavior of asphalt concrete. The Power Model which has only two parameters is found to be the most stable and suitable model for parametric study among the three selected models. More consistent and definite interactions are observed between the parameters of this model and test conditions. However, within the scope of this study, no relations could be developed for the parameters of selected models as functions of bitumen content and test conditions because of limited test data.
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Xing, Yang. "Asymptotic behavior of Bayesian nonparametric procedures /." Umeå : Dept. of Forest Economics, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200935.pdf.
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Cai, Qin. "Detecting Chaotic Signals with Nonlinear Models." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4564.
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In this thesis we apply chaotic dynamic data analysis to the area of discrete time signal processing. A newly developed Hidden Filter Hidden Markov Model is introduced in detection of chaotic signals. Numerical experiments have verified that this novel nonlinear model outperforms linear AR model in detecting chaotic signals buried by noise having similar power spectra. A simple Histogram Model is proposed which can also be used to do detection on the data sets with chaotic behavior. Receiver Operating Characteristics for a variety of noise levels and model classes are reported.
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Gillis, Darren Michael. "Animal aggregation, interference and the ideal free distribution." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63332.
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Wong, Shing-tat, and 黃承達. "Disaggregate analyses of stated preference data for capturing parking choice behavior." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36393678.
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Witkowski, Walter Roy 1961. "SIMULATION ROUTINE FOR THE STUDY OF TRANSIENT BEHAVIOR OF CHEMICAL PROCESSES." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276537.
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Chow, Fung-kiu, and 鄒鳳嬌. "Modeling the minority-seeking behavior in complex adaptive systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29367487.
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Xiao, Feng, and 萧峰. "Hydrodynamic property and breakage behavior of particle aggregates in water: theoretical modeling, CFD simulationand PIV investigation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4284146X.
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Li, Jiukun, and 李久坤. "Equilibrium models in supply chains." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38523589.
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Collins, Kevin Ralph. "The effect of cracks on the dynamic behavior of bars and shafts." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44112.
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Nondestructive methods of detecting cracks in structural components and machinery are important,
both in preventing failures and in establishing maintenance procedures. This thesis considers how
the vibration behavior of cracked members can be modelled mathematically and how these mathematical
models may lead to advancements in crack detection procedures. Two separate cases are
considered: the longitudinal vibration of a cracked bar and the coupled vibrations of a cracked rotating
shaft.
In the longitudinal vibration study, the equation of motion is developed for a cantilevered bar with
a symmetric surface crack. Next, Galerkin's Method is used to obtain one- and two-term approximate
solutions. Both forced and free vibrations of the bar are analyzed. Graphical results showing
the relationships between displacement and crack size, crack position, and forcing frequency are
presented and discussed. Spectral analysis is used to compare uncracked and cracked bar behavior.
Finally, a sensitivity analysis of the forced vibration case is conducted to observe how the forcing
frequency affects the rate of change of steady-state response at the onset of cracking.
In the second part of the thesis, a similar analysis is conducted for a cracked, simply-supported
Timoshenko shaft rotating at a constant angular speed. The equations of motion derived by Wauer
(b) are used as the basis of the study. Again, Galerkin's Method is applied to obtain approximate
solutions. Time histories and spectra are used to observe how changes in various parameters influence
the vibration behavior. The effects of mass eccentricity and gravity are studied. Finally, the
effect of a periodic axial impact load is considered.Master of Science
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Martínez, Saturno José Gregorio. "Some mathematical models to describe the dynamic behavior of the B-10 free-piston stirling engine." Ohio University / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1178133279.
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Lanzas, Lourdes Eneida 1962. "A parametric study on the behavior of slender reinforced concrete frames." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276945.
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By using a nonlinear computer analysis, a parametric study is developed in order to examine the accuracy of the Moment Magnifier Method of the American Concrete Institute Code (ACI 318-83). The variables used in the parametric study are: axial load intensity, P/Po; column reinforcement ratio, rho; slenderness ratio, klu; shape of column cross section, flexural stiffness ratio, and distribution of axial loads. In the parametric study, 216 cases of single bay fixed-base portal frames are examined. The higher moment for each one of these frames at failure are then compared with the design moment predicted by the Moment Magnifier Method of the American Concrete Institute Code (ACI 318-83). The Moment Magnifier Method proved to be very conservative when the columns are subjected to high level of axial loads and when the slenderness ratio is increased.
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Hoelzer, Guy Andrew. "Sexual selection and reproductive behavior in the Cortez damselfish (Stegastes rectifraenum)." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184781.
Full textAbstract:
The evolutionary processes of sexual selection are investigated in this study by developing a new model for the evolution of epigamic traits and examining the effects of male-male competition, female choice and filial cannibalism in a field population of the Cortez damselfish (Stegastes rectifraenum). Two general processes have been proposed to explain the evolution of epigamic traits: the good genes process and the Fisherian process. A third process leading to the evolution of epigamic traits is presented here: the good parent process. Epigamic traits arise through this process by clarifying the differences in non-heritable parental quality among potential mates. A population genetic model is developed, which further suggests that increases in the frequency of good fathers in the population and phenotypic plasticity enhance the evolution of a good parent trait. The relative strengths of female choice and male-male competition were studied in S. rectifraenum by direct observation of reproductive behavior, and through field experiments. Male body size was found to be the single most important correlate of male reproductive success. Males were removed from their territories to determine the extent to which the vacant territories were valued by other local males. All of the territories were quickly recolonized by new males and sites that initially showed the highest reproductive success continued to be the most successful when new residents were present. A second experiment involved standardizing nests in 30 territories. Under these conditions male body size was no longer correlated with reproductive success, indicating that females are strongly influenced by variance in natural nest sites. Consequently, male-male competition over territories containing high quality nest sites, in combination with female choice of those sites, generates the observed correlation between male body size and reproductive success. Partial clutch filial cannibalism by male S. rectifraenum was studied in the same population. A group of custodial males were fed eggs, while controls remained unfed. Both groups were dissected on the next day to determine the number of eggs in their stomachs. Fed males had significantly fewer eggs in their guts, indicating that they indeed feed on the eggs they guard, rather than take them incidently during nest maintenance activities. A second egg feeding experiment showed that male behaviour and reproductive success are little affected by filial cannibalism; thus it is hypothesized that the energy gained by this behaviour is channelled primarily into growth and survival.
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He, Yuesheng. "The intelligent behavior of 3D graphical avatars based on machine learning methods." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1404.
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Bottomley, Gregory Edward. "Modeling the dynamic behavior of rain attenuation." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90918.
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This thesis addresses the problem of predicting satellite path rain fade duration statistics for an arbitrary location, frequency, elevation angle and polarization. It summarizes the development of a dynamic stochastic model. From this model a technique is derived for predicting fade duration statistics for one site using measured attenuation data at another site. This technique is evaluated by comparing predicted and experimental results for several locations, frequencies, elevation angles and polarizations.M.S.
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Wells, Casandra. "An integrative model of psychological and economic factors to better predict consumer saving behavior : theoretical foundations and an empirical investigation." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/29985.
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Dell'Orfano, Michael E. "Fire Behavior and Fuel Modeling of Flammable Shrub Understories in Northeastern Pine-Oak Forests." Digital WPI, 2004. https://digitalcommons.wpi.edu/etd-theses/1070.
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"This thesis evaluates the effectiveness of BEHAVE: Fire Behavior Prediction and Fuel Modeling System in predicting fire behavior in the Northeastern pine-oak forest. This fuel complex is composed primarily of a litter and huckleberry shrub understory with a pitch pine and oak overstory. Measurements of fuel bed physical characteristics, weather and fire behavior are taken from a series of prescribed burn studies in Cape Cod National Seashore in Massachusetts. Site-specific fuel models are constructed which provide the necessary inputs for fire predictions. Observed spread rates and flame lengths are over-predicted by BEHAVE for burns conducted during the winter (dormant season) and under-predicted for burns conducted during the summer (growing season). Attempts to improve winter predictions are successful when the litter moisture is adjusted in order to account for the live wintergreen which increases the overall moisture content of the surface fuels. A sensitivity study is performed where each input parameter is varied over a reasonable interval in order to view its impact on predictions. The model’s high sensitivity to fuel bed depth and 1-hr surface-area-to-volume ratio appear to be the cause for fire prediction deviations during the winter, while the high live fuel moisture contents appear to overwhelm and suppress fire behavior predictions during the summer. It is concluded to overwhelm and suppress fire behavior predictions during the summer. It is concluded that BEHAVE’s representation of fuel complexes as a homogeneous fuel bed with constant properties does not take into account the unique features of the litter and shrub components. An alternative, simple model of fire spread is developed which treats each component as a separate fuel bed. The model is based on a measurement of the heat release rate which can be determined directly through the principle of oxygen consumption calorimetry. Future work using small- and large- scale testing apparatus will help determine the ignition process of the live shrubs and the effect of parameters such as moisture content on the burning characteristics of the fuels. "
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Yang, Yu-Wen. "Behavior of three-span braced columns with equal and unequal spans." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07292009-090428/.
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Francisco, Monica T. "Evaluation of absolute and relative reinforcer value using progressive ratio schedules." Scholarly Commons, 2007. https://scholarlycommons.pacific.edu/uop_etds/672.
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We evaluated behavior exhibited by individuals with developmental disabilities using progressive ratio schedules. High- and low-preferred stimuli were determined based on the results of a paired-stimulus preference assessment and were evaluated in subsequent reinforcer and progressive ratio assessments using concurrent- and single-operant schedules of presentation in a modified reversal design. Results showed that for two participants, stimuli determined to be low-preferred via a preference assessment functioned as reinforcers when evaluated independently of high-preferred stimuli and under gradually increasing response requirements. The results suggest that for cases in which a high-preferred stimulus is unavailable or unfeasible, the contingent delivery of relatively less-preferred stimuli may maintain appropriate behavior, even as response effort is increased. In addition, results of the progressive ratio evaluation are suggestive of stimulus value.
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Trapp, Donald R. "The Development of a Predictive Model of Pretrial Misconduct." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4574.
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The problem of jail overcrowding has forced corrections officials and jail administrators to examine ways in which to better manage available jail space. Pretrial release and detention policies have been a target of this examination as pretrial defendants typically account for 50% of a jail's population. Standards for pretrial release exist, but their administration varies by jurisdiction. The impact of jail overcrowding on pretrial release policies has been to decrease the time available to render a decision. Recent efforts to standardize pretrial release standards in Oregon have not addressed the issue of expediency. The current study examines pretrial misconduct (failure to appear in court and rearrest) with regard to information that is available to jail personnel and release office personnel at the time of arrest, with the specific intent to develop a predictive model of pretrial misconduct that will function as an initial risk assessment. Six hundred defendants arrested in Washington County, Oregon during 1991 served as subjects. The results indicated that 90.9% of all defendants arrested are released pending trial/ and that 22.7% of those released engaged in pretrial misconduct. The results of the loglinear model-building indicated that the variables prior failure-to-appears/ employment, and age were the best predictors of pretrial misconduct. The construction sample (n = 395) accurately predicted 94.5% of the observed pretrial misconduct compared to 90.7% for the validation sample (n = 150). The loglinear analysis yielded 16 typologies (based on the variables included in the model) by which defendants could be ranked as to their risk of pretrial misconduct. Spearman Rank Order coefficents for the construction and validation samples were .847 and .626 respectively. Data were also collected on detained subjects. A Chi-Square test using detained with released ?Ubjects by typology indicated that the categories are not independent (p < .01). Further examination indicated that the detained subjects did represent higher risks of pretrial misconduct as estimated by the typologies. The results also indicated that defendants currently on probation or parole were more likely to detained than other defendants. The results do not reject the assumptions by Sturz {1962), whose Manhattan Bail Project is the basis for pretrial release, that persons with strong ties to the community may pose the least risk of pretrial misconduct. The results also found sex and ethnic differences with regard to pretrial misconduct. The sex differences may have been confounded by age and crime type; however, the ethnic differences may reflect a systemic inability to communicate with Hispanic offenders.
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Calbert, Gregory. "Information, game theory and patch defence in the parasitic wasp Trissolcus basalis Wollaston (Hymenoptera : Scelionidae) /." Title page, contents and summary only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phc143.pdf.
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Patra, Anirban. "Modeling the mechanical behavior and deformed microstructure of irradiated BCC materials using continuum crystal plasticity." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50366.
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The mechanical behavior of structural materials used in nuclear applications is significantly degraded as a result of irradiation, typically characterized by an increase in yield stress, localization of inelastic deformation along narrow dislocation channels, and considerably reduced strains to failure. Further, creep rates are accelerated under irradiation. These changes in mechanical properties can be traced back to the irradiated microstructure which shows the formation of a large number of material defects, e.g., point defect clusters, dislocation loops, and complex dislocation networks. Interaction of dislocations with the irradiation-induced defects governs the mechanical behavior of irradiated metals. However, the mechanical properties are seldom systematically correlated to the underlying irradiated microstructure. Further, the current state of modeling of deformation behavior is mostly phenomenological and typically does not incorporate the effects of microstructure or defect densities.
The present research develops a continuum constitutive crystal plasticity framework to model the mechanical behavior and deformed microstructure of bcc ferritic/martensitic steels exposed to irradiation. Physically-based constitutive models for various plasticity-induced dislocation migration processes such as climb and cross-slip are developed. We have also developed models for the interaction of dislocations with the irradiation-induced defects. A rate theory based approach is used to model the evolution of point defects generated due to irradiation, and coupled to the mechanical behavior. A void nucleation and growth based damage framework is also developed to model failure initiation in these irradiated materials. The framework is used to simulate the following major features of inelastic deformation in bcc ferritic/martensitic steels: irradiation hardening, flow localization due to dislocation channel formation, failure initiation at the interfaces of these dislocation channels and grain boundaries, irradiation creep deformation, and temperature-dependent non-Schmid yield behavior. Model results are compared to available experimental data.
This framework represents the state-of-the-art in constitutive modeling of the deformation behavior of irradiated materials.
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Muliana, Anastasia Hanifah. "Integrated Micromechanical-Structural Framework for the Nonlinear Viscoelastic Behavior of Laminated and Pultruded Composite Materials and Structures." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5142.
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This study introduces a new three-dimensional (3D) multi-scale constitutive framework for the nonlinear viscoelastic analysis of laminated and pultruded composites. Two previously developed nonlinear micromechanical models for unidirectional and in-plane random composite layers are modified to include time-dependent and nonlinear behavior. A new recursive-iterative numerical integration method is introduced for the Schapery nonlinear viscoelastic model and is used to model the isotropic matrix subcells in the two micromodels. In addition, a sublaminate model is used to provide for a through-thickness 3D nonlinear equivalent continuum of a layered medium. The fiber medium is considered as transversely isotropic and linear elastic. Incremental micromechanical formulations of the above three micromodels are geared towards the time integration scheme in the matrix phase. New iterative numerical algorithms with predictor-corrector type steps are derived and implemented for each micromodel to satisfy both the constitutive and homogenization equations. Experimental creep tests are performed for off-axis pultruded specimens in order to calibrate and examine the predictions of the constitutive framework for the multi-axial nonlinear viscoelastic response. Experimental creep data, available in the literature, is also used to validate the micromodel formulation for laminated composite materials. Nonlinear viscoelastic effects at the matrix level, such as aging, temperature, and moisture effects can be easily incorporated in the constitutive framework. The multi-scale constitutive framework is implemented in a displacement-based finite element (FE) code for the analysis of laminated and pultruded structures. Several examples are presented to demonstrate the coupled multi-scale material and structural analysis.
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Verdy, Ariane. "Dynamics of marine zooplankton : social behavior, ecological interactions, and physically-induced variability." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43158.
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Thesis (Ph. D.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2008.Includes bibliographical references (p. [221]-232).
Marine ecosystems reflect the physical structure of their environment and the biological processes they carry out. This leads to spatial heterogeneity and temporal variability, some of which is imposed externally and some of which emerges from the ecological mechanisms themselves. The main focus of this thesis is on the formation of spatial patterns in the distribution of zooplankton arising from social interactions between individuals. In the Southern Ocean, krill often assemble in swarms and schools, the dynamics of which have important ecological consequences. Mathematical and numerical models are employed to study the interplay of biological and physical processes that contribute to the observed patchiness. The evolution of social behavior is simulated in a theoretical framework that includes zooplankton population dynamics, swimming behavior, and some aspects of the variability inherent to fluid environments. First, I formulate a model of resource utilization by a stage-structured predator population with density-dependent reproduction. Second, I incorporate the predator-prey dynamics into a spatially-explicit model, in which aggregations develop spontaneously as a result of linear instability of the uniform distribution. In this idealized ecosystem, benefits related to the local abundance of mates are offset by the cost of having to share resources with other group members. Third, I derive a weakly nonlinear approximation for the steady-state distributions of predator and prey biomass that captures the spatial patterns driven by social tendencies. Fourth, I simulate the schooling behavior of zooplankton in a variable environment; when turbulent flows generate patchiness in the resource field, schools can forage more efficiently than individuals.
(cont.) Taken together, these chapters demonstrate that aggregation/ schooling can indeed be the favored behavior when (i) reproduction (or other survival measures) increases with density in part of the range and (ii) mixing of prey into patches is rapid enough to offset the depletion. In the final two chapters, I consider sources of temporal variability in marine ecosystems. External perturbations amplified by nonlinear ecological interactions induce transient ex-cursions away from equilibrium; in predator-prey dynamics the amplitude and duration of these transients are controlled by biological processes such as growth and mortality. In the Southern Ocean, large-scale winds associated with ENSO and the Southern Annular Mode cause convective mixing, which in turn drives air-sea fluxes of carbon dioxide and oxygen. Whether driven by stochastic fluctuations or by climatic phenomena, variability of the biogeochemical/physical environment has implications for ecosystem dynamics.
by Ariane Verdy.
Ph.D.
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Widjaja, Budi R. "Analytical investigation of composite diaphragms strength and behavior." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07112009-040307/.
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Effertz, Cary Marshall. "A Reference Price Model of Sugar Consumption with Implications on Obesity." Thesis, North Dakota State University, 2007. https://hdl.handle.net/10365/29853.
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Obesity has increased dramatically in the past 25 years. The consumption of added sugar has increased significantly during the same time period. Previous research indicates a direct correlation between the consumption of added sugar and the prevalence of obesity. Sugar has been identified in multiple studies as having addictive or opiate-like qualities. Unquestionably, added sugar consumption has contributed to the current obesity epidemic. Here, we apply a reference price economic model to attempt to describe sugar consumption. Using consumption and price data from the Economic Research Service of the United
States Department of Agriculture, we made a reference price estimation of domestic refined sugar (sucrose) consumption. Using time-series econometric techniques, we tested the effects of internal and external reference prices, in the form of first differenced own price and price of other nutrient classes, respectively, on sugar demand. Results indicate that internal and, particularly, external reference prices do indeed play a role in consumption decisions. However, the model lacks socioeconomic variables that may help to provide a more complete consumption picture.
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Gutierrez, Louis Michael. "Agent-based simulation of disease spread aboard ship." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FGutierrez.pdf.
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Thesis (M.S. in Modeling, Virtual Environments and Simulations (MOVES))--Naval Postgraduate School, March 2005.Thesis Advisor(s): Chris Darken. Includes bibliographical references (p. 47-48). Also available online.
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MacFarlane, Gregory Stuart. "Using big data to model travel behavior: applications to vehicle ownership and willingness-to-pay for transit accessibility." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51804.
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The transportation community is exploring how new "big'' databases constructed by companies or public administrative agencies can be used to better understand travelers' behaviors and better predict travelers' responses to various transportation policies. This thesis explores how a large targeted marketing database containing information about individuals’ socio-demographic characteristics, current residence attributes, and previous residential locations can be used to investigate research questions related to individuals' transportation preferences and the built environment. The first study examines how household vehicle ownership may be shaped by, or inferred from, previous behavior. Results show that individuals who have previously lived in dense ZIP codes or ZIP codes with more non-automobile commuting options are more likely to own fewer vehicles, all else equal. The second study uses autoregressive models that control for spatial dependence, correlation, and endogeneity to
investigate whether investments in public transit infrastructure are associated
with higher home values. Results show that willingness-to-pay estimates obtained from the general spatial Durbin model are less certain than comparable estimates obtained through ordinary least squares. The final study develops an empirical framework to examine a housing market's resilience to price volatility as a function of transportation accessibility. Two key modeling frameworks are considered. The first uses a spatial autoregressive model to investigate the relationship between a home's value, appreciation, and price stability while controlling for endogenous missing regressors. The second uses a latent class model that considers all these attributes simultaneously, but cannot control for endogeneity.
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Panidi, Ksenia. "Essays to the application of behavioral economic concepts to the analysis of health behavior." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209674.
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In this thesis I apply the concepts of Behavioral Economics to the analysis of the individual health care behavior. In the first chapter I provide a theoretical explanation of the link between loss aversion and health anxiety leading to infrequent preventive testing. In the second chapter I analyze this link empirically based on the general population questionnaire study. In the third chapter I theoretically explore the effects of motivational crowding-in and crowding-out induced by external or self-rewards for the self-control involving tasks such as weight loss or smoking cessation.Understanding psychological factors behind the reluctance to use preventive testing is a significant step towards a more efficient health care policy. Some people visit doctors very rarely because of a fear to receive negative results of medical inspection, others prefer to resort to medical services in order to prevent any diseases. Recent research in the field of Behavioral Economics suggests that human's preferences may be significantly influenced by the choice of a reference point. In the first chapter I study the link between loss aversion and the frequently observed tendency to avoid useful but negative information (the ostrich effect) in the context of preventive health care choices. I consider a model with reference-dependent utility that allows to characterize how people choose their health care strategy, namely, the frequency of preventive checkups. In this model an individual lives for two periods and faces a trade-off. She makes a choice between delaying testing until the second period with the risk of a more costly treatment in the future, or learning a possibly unpleasant diagnosis today, that implies an emotional loss but prevents an illness from further development. The model shows that high loss aversion decreases the frequency of preventive testing due to the fear of a bad diagnosis. Moreover, I show that under certain conditions increasing risk of illness discourages testing.
In the second chapter I provide empirical support for the model predictions. I use a questionnaire study of a representative sample of the Dutch population to measure variables such as loss aversion, testing frequency and subjective risk. I consider the undiagnosed non-symptomatic population and concentrate on medical tests for four illnesses that include hypertension, diabetes, chronic lung disease and cancer. To measure loss aversion I employ a sequence of lottery questions formulated in terms of gains and losses of life years with respect to the current subjective life expectancy. To relate this measure of loss aversion to the testing frequency I use a two-part modeling approach. This approach distinguishes between the likelihood of participation in testing and the frequency of tests for those who decided to participate. The main findings confirm that loss aversion, as measured by lottery choices in terms of life expectancy, is significantly and negatively associated with the decision to participate in preventive testing for hypertension, diabetes and lung disease. Higher loss aversion also leads to lower frequency of self-tests for cancer among women. The effect is more pronounced in magnitude for people with higher subjective risk of illness.
In the third chapter I explore the phenomena of crowding-out and crowding-in of motivation to exercise self-control. Various health care choices, such as keeping a diet, reducing sugar consumption (e.g. in case of diabetes) or abstaining from smoking, require costly self-control efforts. I study the long-run and short-run influence of external and self-rewards offered to stimulate self-control. In particular, I develop a theoretical model based on the combination of the dual-self approach to the analysis of the time-inconsistency problem with the principal-agent framework. I show that the psychological property of disappointment aversion (represented as loss aversion with respect to the expected outcome) helps to explain the differences in the effects of rewards when a person does not perfectly know her self-control costs. The model is based on two main assumptions. First, a person learns her abstention costs only if she exerts effort. Second, observing high abstention costs brings disutility due to disappointment (loss) aversion. The model shows that in the absence of external reward an individual will exercise self-control only when her confidence in successful abstention is high enough. However, observing high abstention costs will discourage the individual from exerting effort in the second period, i.e. will lead to the crowding-out of motivation. On the contrary, choosing zero effort in period 1 does not reveal the self-control costs. Hence, this preserves the person's self-confidence helping her to abstain in the second period. Such crowding-in of motivation is observed for the intermediate level of self-confidence. I compare this situation to the case when an external reward is offered in the first period. The model shows that given a sufficiently low self-confidence external reward may lead to abstention in both periods. At the same time, without it a person would not abstain in any period. However, for an intermediate self-confidence, external reward may lead to the crowding-out of motivation. For the same level of self-confidence, the absence of such reward may cause crowding-in. Overall, the model generates testable predictions and helps to explain contradictory empirical findings on the motivational effects of different types of rewards.
Doctorat en Sciences économiques et de gestion
info:eu-repo/semantics/nonPublished
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Limbu, Dilip Kumar. "Contextual information retrieval from the WWW." Click here to access this resource online, 2008. http://hdl.handle.net/10292/450.
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Contextual information retrieval (CIR) is a critical technique for today’s search engines in terms of facilitating queries and returning relevant information. Despite its importance, little progress has been made in its application, due to the difficulty of capturing and representing contextual information about users. This thesis details the development and evaluation of the contextual SERL search, designed to tackle some of the challenges associated with CIR from the World Wide Web. The contextual SERL search utilises a rich contextual model that exploits implicit and explicit data to modify queries to more accurately reflect the user’s interests as well as to continually build the user’s contextual profile and a shared contextual knowledge base. These profiles are used to filter results from a standard search engine to improve the relevance of the pages displayed to the user. The contextual SERL search has been tested in an observational study that has captured both qualitative and quantitative data about the ability of the framework to improve the user’s web search experience. A total of 30 subjects, with different levels of search experience, participated in the observational study experiment. The results demonstrate that when the contextual profile and the shared contextual knowledge base are used, the contextual SERL search improves search effectiveness, efficiency and subjective satisfaction. The effectiveness improves as subjects have actually entered fewer queries to reach the target information in comparison to the contemporary search engine. In the case of a particularly complex search task, the efficiency improves as subjects have browsed fewer hits, visited fewer URLs, made fewer clicks and have taken less time to reach the target information when compared to the contemporary search engine. Finally, subjects have expressed a higher degree of satisfaction on the quality of contextual support when using the shared contextual knowledge base in comparison to using their contextual profile. These results suggest that integration of a user’s contextual factors and information seeking behaviours are very important for successful development of the CIR framework. It is believed that this framework and other similar projects will help provide the basis for the next generation of contextual information retrieval from the Web.
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Hu, Wei Shu. "Mining product features from online reviews." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2148259.
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Granovskiy, Boris. "Modeling Collective Decision-Making in Animal Groups." Doctoral thesis, Uppsala universitet, Matematiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-180972.
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Many animal groups benefit from making decisions collectively. For example, colonies of many ant species are able to select the best possible nest to move into without every ant needing to visit each available nest site. Similarly, honey bee colonies can focus their foraging resources on the best possible food sources in their environment by sharing information with each other. In the same way, groups of human individuals are often able to make better decisions together than each individual group member can on his or her own. This phenomenon is known as "collective intelligence", or "wisdom of crowds." What unites all these examples is the fact that there is no centralized organization dictating how animal groups make their decisions. Instead, these successful decisions emerge from interactions and information transfer between individual members of the group and between individuals and their environment. In this thesis, I apply mathematical modeling techniques in order to better understand how groups of social animals make important decisions in situations where no single individual has complete information. This thesis consists of five papers, in which I collaborate with biologists and sociologists to simulate the results of their experiments on group decision-making in animals. The goal of the modeling process is to better understand the underlying mechanisms of interaction that allow animal groups to make accurate decisions that are vital to their survival. Mathematical models also allow us to make predictions about collective decisions made by animal groups that have not yet been studied experimentally or that cannot be easily studied. The combination of mathematical modeling and experimentation gives us a better insight into the benefits and drawbacks of collective decision making, and into the variety of mechanisms that are responsible for collective intelligence in animals. The models that I use in the thesis include differential equation models, agent-based models, stochastic models, and spatially explicit models. The biological systems studied included foraging honey bee colonies, house-hunting ants, and humans answering trivia questions.
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Cuzziol, Marcos Fernandez. "Estados superpostos: proposta de modelo matemático para games 3D." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/27/27159/tde-13052013-093444/.
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O comportamento de personagens de games 3D em geral apresenta-se de modo repetitivo e previsível. No presente trabalho, avalia-se que o principal motivo para essa previsibilidade não está numa limitação intrínseca da programação desses comportamentos, mas, antes, no modelo matemático utilizado como base para a construção do programa. Através de estudos de caso, identifica-se o modelo mais comum empregado em games e mostra-se que esse modelo não precisa ser necessariamente respeitado. Exemplos de comportamentos de personagens de games e de outras criaturas virtuais são apresentados como demonstração de que é possível obter-se comportamentos não previsíveis e, ao mesmo tempo, não aleatórios, mas orientados a objetivos pré-estabelecidos, a partir de sequências de instruções programadas. Para avaliar um modelo matemático alternativo, apresentase primeiro uma breve descrição da mecânica quântica e das implicações que o desenvolvimento dessa teoria teve sobre a compreensão do real. O trabalho apresenta então propostas para a criação de um novo modelo matemático para games 3D, inspiradas na interpretação de Everett da mecânica quântica. Mostra-se a seguir como esse novo modelo poderia gerar games 3D que se adaptariam automaticamente às habilidades específicas do usuário, e como esse novo modelo poderia facilitar a criação de enredos realmente interativos.The behavior of 3D game\'s characters is usually repetitive and predictable. In this work, it is estimated that the main reason for this predictability is not due to an intrinsic limitation of the programming of these behaviors, but rather to the mathematical model applied for building the program. Through case studies, the most common model used in games is identified, and it\'s shown that this model does not necessarily have to be followed. Examples of behaviors of game characters and other virtual creatures are presented as a demonstration that it is possible to create unpredictable and, at the same time, not random, but rather oriented to preestablished goals, behaviors merely from programmed instruction sequences. To evaluate an alternative mathematical model, a brief description of quantum mechanics is presented, as well as the implications that the development of this theory had on our understanding of the real. The work then presents proposals for the creation of a new mathematical model for 3D games, inspired by the Everett interpretation of quantum mechanics. Following, it\'s shown how this new model could generate 3D games that adapt automatically to user-specific skills, and how this new model could facilitate the creation of truly interactive storylines.
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Marciniuk, Fernanda Ledo. "Uma aplicação do algoritmo colonia de formigas no problema de corte ordenado." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306264.
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Orientadores: Antonio Carlos Moretti, Luis Leduino de Salles NetoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: O problema de corte de estoque ordenado, um problema relativamente novo na literatura, e uma adaptação do problema de corte de estoque tradicional onde algumas restrições quanto a limitação do numero de ordens de produção em processamento são adicionadas. Esta dissertação tem como objetivo estudar uma nova abordagem deste problema utilizando uma aplicação da metaheurística colônia de formigas. Esta metaheurística utiliza os princípios de auto-organização de uma população de formigas visando a resolução de problemas de otimização combinatorial
Abstract: The Ordered Cutting Stock Problem (OCSP), a relatively recent problem in technical literarture, is a variant of the more well-known Cutting Stock Problem (CSP). This variant includes some new constraints in the mathematical formulation, regarding the number of production orders being processed simultaneously. This work studies a new approach to solve the OCSP, applying the Ant Colony Optimization (ACO) metaheurisitic. This metaheuristic is based in the self-organizing principles that govern ant population's behaviour, solving combinatorial optimization problems
Mestrado
Pesquisa Operacional
Mestre em Matemática Aplicada
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Aarts, Geert. "Modelling space-use and habitat preference from wildlife telemetry data." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/327.
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