Дисертації з теми "Computational model of emotion"
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1
Warner, Robert L. "A computational model of human emotion." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12302008-063852/.
2
Lewis, Suzanne Carole. "Computational models of emotion and affect." Thesis, University of Hull, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417166.
3
Du, Shichuan. "A Computational Model of the Production and Perception ofFacial Expressions of Basic and Compound Emotions." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405989041.
4
Fröcklin, Henry. "Computational model for morality and emotions in EmoBN." Thesis, Linköpings universitet, Medie- och Informationsteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-112096.
Анотація:
This master thesis presents an approach on how to design moral behaviour in a scenario with een. een is an iteration of emobn which is based on bn, an action selection system with activation dynamics among modules, goal oriented and capable of prediction and planing. The design is based on current research from prominent psychologist like Haidt and uses Mikhial’s umg framework for causal and intentional validation. Also Roseman’s appraisal model and Haidt’s mft is used for determining moral emotions in a moral context. The design is tested against empirical results from philosophical experiment know as the trol- ley problem, a well known moral dilemma.
5
Allen, Stephen Richard. "Concern processing in autonomous agents." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369169.
6
Srinivasan, Ramprakash. "Computational Models of the Production and Perception of Facial Expressions." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531239299392184.
7
Velásquez, Juan David. "Cathexis--a computational model for the generation of emotions and their influence in the behavior of autonomous agents." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10651.
Анотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 93-98).
by Juan David Velásquez.
M.S.
8
Monteith, Kristine Perry. "Automatic Generation of Music for Inducing Emotive and Physiological Responses." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3753.
Анотація:
Music and emotion are two realms traditionally considered to be unique to human intelligence. This dissertation focuses on furthering artificial intelligence research, specifically in the area of computational creativity, by investigating methods of composing music that elicits desired emotional and physiological responses. It includes the following: an algorithm for generating original musical selections that effectively elicit targeted emotional and physiological responses; a description of some of the musical features that contribute to the conveyance of a given emotion or the elicitation of a given physiological response; and an account of how this algorithm can be used effectively in two different situations, the generation of soundtracks for fairy tales and the generation of melodic accompaniments for lyrics. This dissertation also presents research on more general machine learning topics. These include a method of combining output from base classifiers in an ensemble that improves accuracy over a number of different baseline strategies and a description of some of the problems inherent in the Bayesian model averaging strategy and a novel algorithm for improving it.
9
Guan, Jinyan. "Bayesian Generative Modeling of Complex Dynamical Systems." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612950.
Анотація:
This dissertation presents a Bayesian generative modeling approach for complex dynamical systems for emotion-interaction patterns within multivariate data collected in social psychology studies. While dynamical models have been used by social psychologists to study complex psychological and behavior patterns in recent years, most of these studies have been limited by using regression methods to fit the model parameters from noisy observations. These regression methods mostly rely on the estimates of the derivatives from the noisy observation, thus easily result in overfitting and fail to predict future outcomes. A Bayesian generative model solves the problem by integrating the prior knowledge of where the data comes from with the observed data through posterior distributions. It allows the development of theoretical ideas and mathematical models to be independent of the inference concerns. Besides, Bayesian generative statistical modeling allows evaluation of the model based on its predictive power instead of the model residual error reduction in regression methods to prevent overfitting in social psychology data analysis. In the proposed Bayesian generative modeling approach, this dissertation uses the State Space Model (SSM) to model the dynamics of emotion interactions. Specifically, it tests the approach in a class of psychological models aimed at explaining the emotional dynamics of interacting couples in committed relationships. The latent states of the SSM are composed of continuous real numbers that represent the level of the true emotional states of both partners. One can obtain the latent states at all subsequent time points by evolving a differential equation (typically a coupled linear oscillator (CLO)) forward in time with some known initial state at the starting time. The multivariate observed states include self-reported emotional experiences and physiological measurements of both partners during the interactions. To test whether well-being factors, such as body weight, can help to predict emotion-interaction patterns, we construct functions that determine the prior distributions of the CLO parameters of individual couples based on existing emotion theories. Besides, we allow a single latent state to generate multivariate observations and learn the group-shared coefficients that specify the relationship between the latent states and the multivariate observations. Furthermore, we model the nonlinearity of the emotional interaction by allowing smooth changes (drift) in the model parameters. By restricting the stochasticity to the parameter level, the proposed approach models the dynamics in longer periods of social interactions assuming that the interaction dynamics slowly and smoothly vary over time. The proposed approach achieves this by applying Gaussian Process (GP) priors with smooth covariance functions to the CLO parameters. Also, we propose to model the emotion regulation patterns as clusters of the dynamical parameters. To infer the parameters of the proposed Bayesian generative model from noisy experimental data, we develop a Gibbs sampler to learn the parameters of the patterns using a set of training couples. To evaluate the fitted model, we develop a multi-level cross-validation procedure for learning the group-shared parameters and distributions from training data and testing the learned models on held-out testing data. During testing, we use the learned shared model parameters to fit the individual CLO parameters to the first 80% of the time points of the testing data by Monte Carlo sampling and then predict the states of the last 20% of the time points. By evaluating models with cross-validation, one can estimate whether complex models are overfitted to noisy observations and fail to generalize to unseen data. I test our approach on both synthetic data that was generated by the generative model and real data that was collected in multiple social psychology experiments. The proposed approach has the potential to model other complex behavior since the generative model is not restricted to the forms of the underlying dynamics.
10
Antos, Dimitrios. "Deploying Affect-Inspired Mechanisms to Enhance Agent Decision-Making and Communication." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10107.
Анотація:
Computer agents are required to make appropriate decisions quickly and efficiently. As the environments in which they act become increasingly complex, efficient decision-making becomes significantly more challenging. This thesis examines the positive ways in which human emotions influence people’s ability to make good decisions in complex, uncertain contexts, and develops computational analogues of these beneficial functions, demonstrating their usefulness in agent decision-making and communication. For decision-making by a single agent in large-scale environments with stochasticity and high uncertainty, the thesis presents GRUE (Goal Re-prioritization Using Emotion), a decision-making technique that deploys emotion-inspired computational operators to dynamically re-prioritize the agent’s goals. In two complex domains, GRUE is shown to result in improved agent performance over many existing techniques. Agents working in groups benefit from communicating and sharing information that would otherwise be unobservable. The thesis defines an affective signaling mechanism, inspired by the beneficial communicative functions of human emotion, that increases coordination. In two studies, agents using the mechanism are shown to make faster and more accurate inferences than agents that do not signal, resulting in improved performance. Moreover, affective signals confer performance increases equivalent to those achieved by broadcasting agents’ entire private state information. Emotions are also useful signals in agents’ interactions with people, influencing people’s perceptions of them. A computer-human negotiation study is presented, in which virtual agents expressed emotion. Agents whose emotion expressions matched their negotiation strategy were perceived as more trustworthy, and they were more likely to be selected for future interactions. In addition, to address similar limitations in strategic environments, this thesis uses the theory of reasoning patters in complex game-theoretic settings. An algorithm is presented that speeds up equilibrium computation in certain classes of games. For Bayesian games, with and without a common prior, the thesis also discusses a novel graphical formalism that allows agents’ possibly inconsistent beliefs to be succinctly represented, and for reasoning patterns to be defined in such games. Finally, the thesis presents a technique for generating advice from a game’s reasoning patterns for human decision-makers, and demonstrates empirically that such advice helps people make better decisions in a complex game.Engineering and Applied Sciences
11
Parsapoor, Mahboobeh. "Towards Emotion inspired Computational Intelligence (EiCI)." Doctoral thesis, Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-30106.
Анотація:
One of the main challenges in the computational intelligence (CI) community is to develop nature-inspired algorithms that can efficiently solve real-world problems such as the prediction of space weather phenomena. An early example in this context is taking inspiration from the biological neurons in the mammal’s nervous system and developing an artificial neuron. This work laid the foundation for artificial neural networks (ANNs) that aim to mimic the connections between neurons in the mammal’s nervous system and to develop an artificial model of the brain. ANNs are well-known CI models that have shown high generalization capability when solving real-world problems, e.g., chaotic time-series prediction problems. However, ANNs mostly tend to suffer from long computation time and high model complexity. This thesis presents a new category of CI paradigms by taking inspiration from emotions, and these CI models are referred to as emotion-inspired computational intelligence models (EiCIs). In the thesis, I have outlined the preliminary steps that have been taken to develop EiCIs. These steps include studying different emotional theories and hypotheses, designing and implementing CI models for two specific applications in artificial intelligence (prediction and optimization), evaluating the performance of the new CI models, and comparing the obtained results with the results of well-known CI models (e.g., ANNs) and discussing the potential improvement that can be achieved. The first step, and a significant contribution of this thesis, is to review the various definitions of emotions and to investigate which emotional theories that are the most relevant for developing a CI model. Amongst different theories and hypotheses of emotions, the fear conditioning hypothesis as well as affect theory have been two main sources of inspiration in the development of the EiCIs proposed in this thesis. The fear conditioning hypothesis that was first proposed by LeDoux reveals some important characteristics of the underlying neural structure of fear conditioning behavior in biological systems. Based on the features of such networks, it could be an applicable hypothesis to be the basis of the development of a subgroup of EiCIs that could be used for prediction applications, e.g. BELIMs (Brain Emotional Learning Inspired Models), and as emotion-inspired engines for decision-making applications.The second emotional theory of the thesis is the affect theory (which was first suggested by Silvan Tomkins) that describes what the basic emotions are and how they can be associated with facial expressions. A mechanism to express the basic emotional feelings is also useful in designing another category of EiCIs that are referred to as emotion-inspired optimization methods. The fundamental hypotheses of the thesis, have led to developing EiCIs, can be presented as follows. The first hypothesis is that the neural structure of fear conditioning can be considered to be a nature-based system with the capability to show intelligent behavior through its functionality. This hypothesis is stated on the basis of the three main characteristics of the neural structure of fear conditioning behavior.The first characteristic is that the amygdala is the main center for processing fear-induced stimuli and that it provides the fear reaction through its interaction with other regions of the brain such as the sensory cortex, the thalamus, and the hippocampus. The second characteristic is that the procedure of processing of fearful stimuli and the provision of emotional reactions is simple and quick. The third aspect is that the amygdala not only provides fear responses but also learns to predict aversive events by interacting with other regions of the brain, which means that an intelligent behavior emerges.The second hypothesis is that the system in which the three monoamines neurotransmitters serotonin, dopamine, and noradrenalin and thus produces emotional behaviors, can be viewed as a biological system associated with the emergence of intelligent behavior.The above hypotheses state that a suitable way to develop new CI models is to take inspiration from the neural structure of fear conditioning and the natural system of three monoamine neurotransmitters. A significant contribution of this thesis is the evaluation of the ability of EiCIs by examining them to solve real-world problems such as the prediction of space weather phenomena (e.g., predicting real time-series such as sunspot number, auroral electrojet index, and disturbance time index) and the optimization of some central procedures in network communications. These evaluations have led to that comparable results have been obtained, which in turn supports the conclusion that EiCIs have acceptable and reasonable performance regarding computation time and model complexity. However, to achieve the final goal of the research study (i.e., to develop a CI model with low computation time and low model complexity), some enhancements of EiCIs are necessary. Moreover, new designs and implementations of these models can be developed by taking inspiration from other theories.
12
Davis, Felecia. "Softbuilt : computational textiles and augmenting space through emotion." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113943.
Анотація:
Thesis: Ph. D. in the field of Architecture: Design and Computation, Massachusetts Institute of Technology, Department of Architecture, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 270-284).
When we inhabit, wear, and make textiles we are in conversation with our pre-historical and historical past and in a sense already connected to what is to come by the structure of fabric that operates as a mode of understanding the world. Textiles bind us together as a species in every culture on the planet, though we humans may use and make this material in different ways. In architecture, textiles made of animal skins or plant fibres were probably used to make the first shelters, as both protective clothing and enclosing space. As a liminal space between the body and environment these textiles became places of exchange and communication of information between people and their communities through shelter and clothing. This communication is an expression of personality and mood which makes an impression on those who would look upon the shelter or clothing. This communication is directly related to the expression of the material. The hypothesis of this dissertation is that textiles communicate emotion through material expression via vision and touch. Furthermore, computation augments what designers can communicate about emotion to people by the evocative power of transforming textile expressions. I present four experiments in this dissertation that explore the emotional and expressive attributes of computational textiles - textiles that respond to their environment via programming and sensors. Two experiments begin to define computational textiles through the acts of making the textiles. Two experiments with architectural textile panels begin to look at emotions communicated to people through vision and touch using computational textiles. Softbuilt refers to things and places made using methods that connect computational material expression, space and emotion. The contributions of the dissertation are the framework, Softbuilt, for understanding what computational textiles are, methods of fabrication for computational textiles, and an understanding of emotions communicated to people from computational textile expression.
by Felecia A. Davis.
Ph. D. in the field of Architecture: Design and Computation
13
Al-Dahoud, Ahmad. "The computational face for facial emotion analysis: Computer based emotion analysis from the face." Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/17384.
Анотація:
Facial expressions are considered to be the most revealing way of understanding the human psychological state during face-to-face communication. It is believed that a more natural interaction between humans and machines can be undertaken through the detailed understanding of the different facial expressions which imitate the manner by which humans communicate with each other.
In this research, we study the different aspects of facial emotion detection, analysis and investigate possible hidden identity clues within the facial expressions. We study a deeper aspect of facial expressions whereby we try to identify gender and human identity - which can be considered as a form of emotional biometric - using only the dynamic characteristics of the smile expressions. Further, we present a statistical model for analysing the relationship between facial features and Duchenne (real) and non-Duchenne (posed) smiles. Thus, we identify that the expressions in the eyes contain discriminating features between Duchenne and non-Duchenne smiles.
Our results indicate that facial expressions can be identified through facial movement analysis models where we get an accuracy rate of 86% for classifying the six universal facial expressions and 94% for classifying the common 18 facial action units. Further, we successfully identify the gender using only the dynamic characteristics of the smile expression whereby we obtain an 86% classification rate. Likewise, we present a framework to study the possibility of using the smile as a biometric whereby we show that the human smile is unique and stable.Al-Zaytoonah University
14
King, Christopher Paul. "Emotion and adventure therapy : A model." Thesis, University of Canterbury. Psychology, 1998. http://hdl.handle.net/10092/6967.
Анотація:
The cognitive zeitgeist within the psychotherapy literature of the last decades has tended to obscure the role of emotion, emphasising instead the role of cognition and behaviour in psychotherapeutic change. It seems anomalous that clinically oriented psychologists should have neglected emotion to such a degree, as emotional distress of one type or another is the currency of psychotherapy. Concurrent with the neglect of emotion in the psychotherapy literature, within general psychology there has been a resurgence of interest in emotion as a fundamental aspect of human experience. Following the course set by Jeremy Safran & Leslie Greenberg, the individuals who have alerted the psychotherapeutic community to the need for cognisance of the general psychology work on emotion, an attempt has been made to form an amalgam which acknowledges both the therapeutic and academic knowledge about emotion. That is the first element of the discussion presented below.
The second major element is Adventure Therapy. Adventure Therapy, as a means of addressing difficulties of various sorts, has been a part of the therapeutic landscape for almost one hundred years. There has been a recent resurgence of interest in
Adventure Therapy, particularly as the need for alternatives to traditional ‘talking’ therapies for some populations has been recognised. The view taken here is that Adventure Therapy is indeed a form of psychotherapy and not merely a specialised form of recreation undertaken with particular populations.
In much the same way as many other forms of therapy, Adventure Therapy is partially defined by the environment, procedures and techniques which constitute the practical aspect of the approach. Behind this is the theory that provides the rationale for the more tangible aspects. For instance, classical psychoanalysis has the unconscious, free association, and the ubiquitous couch, while Adventure Therapy has the outdoors and activities such as climbing, abseiling, kayaking, and tramping. As will become apparent, for Adventure Therapy, it is the activities and the environment within which they take place that is crucial to the therapeutic effect.
Most psychotherapeutic schools, to greater or lesser degrees, have attempted, in the course of their theorising, to say something about the role of emotion. This does not appear to be the case for Adventure Therapy. By way of redressing this notable deficiency, the discussion below draws on the implications that stem from a synthesis emerging from both the therapeutic and academic literatures.
Chapter 1 is an introduction to Adventure Therapy with particular emphasis on the existing theoretical models which have been applied to Adventure Therapy. Also discussed are the types of programs which exist and the populations to which they are directed. Similarly, Chapter 2 delineates a number of features of emotion drawing on the general academic research and theory.
Chapter 3 outlines the ways in which various psychotherapeutic schools have conceptualised emotion. The emotional change processes which contribute to the purported psychotherapeutic effect are also examined. Chapter 4 describes the general therapeutic implications that emerge from the synthesis of the therapeutic and academic literatures.
Chapter 5 is an examination of two particular bodies of research that relate to both emotion and adventure; coping and risk-taking. The purpose of this chapter is to demonstrate that the academic research provides some useful signposts as to the role of emotion in Adventure Therapy particularly with regard to the complexity of the factors which may need to be considered when examining adventure specifically. However, what also becomes apparent are the limitations of scope and methodology that will need to be addressed for research within the Adventure Therapy context.
Chapter 6 presents a model of the role of emotion in Adventure Therapy. The model, essentially an ecological constructivist analysis, draws on the preceding chapters and is designed to provide a starting point from which a research program can be undertaken. It suggests that the activities and processes which are inherent parts of Adventure Therapy provide an adaptive context within which emotion plays a central therapeutic role by way of its ability to penetrate multiple aspects of being.
15
Cheng, Jia Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Computational model of epirentinal stimulation." Awarded by:University of New South Wales. Graduate School of Biomedical Engineering, 2005. http://handle.unsw.edu.au/1959.4/23960.
Анотація:
The quality of visual perception with epiretinal electric stimulation strongly depends on the configuration of electrode arrays. Such arrays at the surface of the retina should excite only cells within a local area, but in practice, they exhibit some cross-talk, possibly leading to a smearing of focal activation of the retina. In this study, a passive model of extracellular voltage distribution arising from epiretinal stimulation is solved using the method of finite differences, in order to explore the voltage and current distributions of a hexagonal electrode array configuration. Results of this study suggest that the hexagonal electrode arrangement is effective in providing targeted focal activation of retinal tissue. Cross-talk between hexagonal clusters may be minimized by stimulus paradigms which utilize six return (or guard) electrodes around each stimulus electrode.
16
Bin, Muhammad Ibrahim Israr. "Computational Model of Pitting Corrosion." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3167.
Анотація:
Pitting corrosion is a form of highly localized corrosion that can lead to crack and failure of a structure. Study on pitting corrosion is necessary in order to predict and prevent the risk of failure of structure susceptible to corrosion. In this thesis, a combination of Cellular Automata (CA) and Boundary Element Method (BEM) was developed to simulate pitting corrosion growth under certain environment. It is assumed that pitting corrosion can be simplified to electrochemical corrosion cell. The distribution of potential around this corrosion cell can then be simulated by BEM. This distribution potential represents cathodic and anodic reactions around the corrosion cell. A CA model was developed that uses transition rules reflecting mechanism of pitting corrosion. The CA model has two types of cell states, one reflecting BEM simulation results and the other reflecting the status of corrosion cell (anode, cathode, and passive metal’s surface). For every CA iteration, the CA decides the state of the corrosion cells (the location and size of anode, cathode) while BEM simulate the level of electrochemical activity at discrete location on the surface (represented by potential distribution). In order to demonstrate the methodology, a simple case of rectangular corrosion cell with varied dimensions and under different polarization functions is considered. Results show certain shapes tend to grow at certain type environment and these pits are comparable to commonly observed pit shapes. In addition, stress analysis was carried out to investigate the severity of corrosion pits of varying shapes and sizes. Results show that certain pits induced highly varying stress concentration as it grows over time, while others have more steady increase of stress concentration.
17
Hempinstall, Susan. "Computational Model of Human Memory." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35096.
Анотація:
Theories of Extended Mind have evolved in waves to reach the present state of disagreement with regard to whether or not external artefacts become part of the mind when used for memory purposes. A four-step approach has been used to address and resolve this disagreement. First, a new component for models of mind which provides a saliency function is provided. This saliency function corresponds to computational elements found necessary in large mainframe computer systems for handling rich data environments. Second, there is introduced a Computational Model of Memory containing the new component which models the operation of human memory. The Computational Model of Memory contains four interoperative elements including the new component, short-term memory, long-term memory, and a cross-reference associator. Third, the work of Marcin Milkowski is drawn upon to obtain a general method of assessing a computational model’s well-formedness, and the method is applied to prove the adequacy of the Computational Model of Memory. According to Milkowski’s schema, the model satisfies most criteria for a well-formed computational model, including in particular a separation between conceptual elements of the model, and constitutive elements of the model, which while explicitly related, are required to subsist at separate logical conceptual levels. Fourth, the Computational Model of Memory is applied to outstanding arguments in Extended Mind to clarify and resolve several of these arguments. The model serves to highlight where the nature of the disagreement depends upon a category error of reference, and further resolves a key disagreement by demonstrating that the mind may treat external artefacts as an alternative realizable constitutive element of short-term and long-term memory.
18
Sessions, Blake A. "A computational bow-spring model." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/65303.
Анотація:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2011."May 2010." Cataloged from PDF version of thesis.
Bow-springs find few applications in industry. Principally, they are used in archery. In addition, they have found some use in a compression-spring mode in the field of biomechatronics, to emulate elastic human legs. The mechanical behavior (characterized by deflected shape and deformation force) is difficult to model, because internal forces and moments and the geometry are both unknown. The only closed-form solutions to such systems are relatively useless to a mechanical engineer. This work comprises an iterative model developed in MATLAB that computes the mechanical behavior of buckled beam (or bow-spring) sections, over a range of parameters and geometries, to be used in the development and testing of compression bow-springs as parallel loading systems to the human leg.
by Blake A. Sessions.
S.B.
19
Vorobtsova, Natalya. "Computational model of coronary tortuosity." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/51267.
Анотація:
Coronary tortuosity is the abnormal curving and twisting of the coronary arteries. Although the phenomenon of coronary tortuosity is frequently encountered by cardiologists its clinical significance is unclear. It is known that coronary tortuosity has significant influence on the hemodynamics inside the coronary arteries, but it is difficult to draw definite conclusions due to the lack of patient-specific studies and an absence of a clear definition of tortuosity.
In this work, in order to investigate a relation of coronary tortuosity to such diseases as atherosclerosis, ischemia, and angina, a numerical investigation of coronary tortuosity was performed. First, we studied a correlation between a degree of tortuosity and flow parameters in three simplified vessels with curvature and zero torsion. Next, a statistical analysis based on flow calculations of 23 patient-based real tortuous arteries was performed in order to investigate a correlation between tortuosity and flow parameters, such as pressure drop, wall shear stress distribution, and a strength of helical flow, represented by a helicity intensity, and concomitant risks.
Results of both idealized and patient-specific studies indicate that a risk of perfusion defects grows with an increased degree of tortuosity due to an increased pressure drop downstream an artery. According to the results of the patient-specific study, a risk of atherosclerosis decreases in more tortuous arteries - a result different from an outcome of the idealized study of arteries with zero torsion. Consequently, a modeling of coronary tortuosity should take into account all aspects of tortuosity including a heart shape that introduces additional torsion to arteries. Moreover, strength of a helical flow was shown to depend strongly on a degree of tortuosity and affect flow alterations and accompanying risks of developing atherosclerosis and perfusion defects. A corresponding quantity, helicity intensity, might have a potential to be implemented in future studies as a universal single parameter to describe tortuosity and assess congruent impact on the health of a patient.Master of Science
20
Keshtkar, Fazel. "A Computational Approach to the Analysis and Generation of Emotion in Text." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20137.
Анотація:
Sentiment analysis is a field of computational linguistics involving identification,
extraction, and classification of opinions, sentiments, and emotions expressed in
natural language. Sentiment classification algorithms aim to identify whether the author of a text has a positive or a negative opinion about a topic. One of the main indicators which help to detect the opinion are the words used in the texts. Needless to say, the sentiments expressed in the texts also depend on the syntactic structure and the discourse context. Supervised machine learning approaches to sentiment classification were shown to achieve good results. Classifying texts by emotions requires finer-grained analysis than sentiment classification. In this thesis, we explore the task of emotion and mood classification for blog postings. We propose a
novel approach that uses the hierarchy of possible moods to achieve better results than
a standard flat classification approach. We also show that using sentiment orientation features improves the performance of classification. We used the LiveJournal blog corpus as a dataset to train and evaluate our method.
Another contribution of this work is extracting paraphrases for emotion terms based on the six basics emotions proposed by Ekman (\textit{happiness, anger, sadness, disgust, surprise, fear}). Paraphrases are different ways to express the same information. Algorithms to extract and automatically identify paraphrases are of interest from both linguistic and practical points of view. Our paraphrase extraction method is based on a bootstrapping algorithms that starts with seed words. Unlike in previous work, our algorithm does not need a parallel corpus.
In Natural Language Generation (NLG), paraphrasing is employed to create more varied and natural text. In our research, we extract paraphrases for emotions, with the goal of using them to automatically generate emotional texts (such as friendly or hostile texts) for conversations between intelligent agents and characters in educational games.
Nowadays, online services are popular in many disciplines such as: e-learning, interactive games, educational games, stock market, chat rooms and so on. NLG methods can be used in order to generate more interesting and normal texts for such applications. Generating text with emotions is one of the contributions of our work.
In the last part of this thesis, we give an overview of NLG from an applied
system's points of view. We discuss when NLG techniques can be used; we explained the requirements analysis and specification of NLG systems. We also, describe the main NLG tasks of content determination, discourse planning, sentence aggregation, lexicalization, referring expression generation, and linguistic realisation. Moreover, we describe our Authoring Tool that we developed in order to allow writers without programming skills to automatically generate texts for educational games.
We develop an NLG system that can generate text with different emotions. To do this, we introduce our pattern-based model for generation. We show our model starts with initial patterns, then constructs extended patterns from which we choose ``final'' patterns that are suitable for generating emotion sentences. A user can generate sentences to express the desired emotions by using our patterns. Alternatively, the user can use our Authoring Tool to generate sentences with emotions. Our acquired paraphrases will be employed by the tool in order to generate more varied outputs.
21
Otwell-Dove, Rebecca. "Adverse Childhood Experiences, Familial Emotion Socialization, and Adult Emotion Regulation: A Moderation Model." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3677.
Анотація:
Adverse childhood experiences (ACEs) have been associated with maladaptive outcomes, including difficulties with emotion regulation (ER). ER difficulties, in turn, increase risk for experiencing physical and mental health problems. Parental emotion socialization is one factor that has been associated with ER skills across development. No known studies, however, have examined whether parental emotion socialization moderates the relationship between ACEs and ER difficulties. In the current study, undergraduates (N = 678) completed questionnaires about their history of ACEs, parental emotion socialization experiences, and current ER difficulties. Correlational results indicated a positive correlation between ACEs and ER difficulties. Results of the hierarchical multiple regression analyses found a significant moderation effect only within the context of distress reaction (DR) parenting. Results suggested that the link between ACEs and adult ER difficulties was stronger in the context of low to moderate DR parenting and relatively weak in circumstances of high DR parenting.
22
Zhang, Shibingfeng. "Emotion Identification in Italian Opera." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23510/.
Анотація:
This work aims to develop classification models able to automatically perform the task of emotion identification on Italian arias. These models enable the musicologists and the public interested in opera to investigate the emotion of Italian aria in a systematical way.
An aria can be seen as an independent unit of opera that is sung by one character. Each aria contains 1 to 8 verses. Considering an aria may transmit more than one emotion, a lower level granularity is adopted: the identification of the emotion transmitted at the verse level. On the basis of a manually labelled corpus comprised of 2,500 aria verses with their corresponding emotion,
the �first part of this work investigates different text representations and classification approaches.
Building on the results of the exploration in the �first part, the second part investigates emotion identification at the aria level. The size of supervised data is expanded by means of self-learning. The verse-level annotation is converted into aria-level annotation and each aria is assigned up to two emotion
labels. I experimented with pre-trained character trigram embeddings and convolutional neural network.
For the emotion identification at the verse level, the combination of character trigram based TF-IDF and neural network with 2 hidden layers outperformed other combinations, achieving an accuracy of 0.47 on the test set. As for the emotion identification at the aria level, a convolutional neural network combined with character trigram based embeddings developed based on a corpus of Italian arias achieved an accuracy of 0:68.
23
Mayo, Bruce. "A computational model of derivational morphology." [S.l. : s.n.], 1999. http://www.sub.uni-hamburg.de/disse/386/Disse.pdf.
24
Johansson, Björn. "Model management for computational system design /." Linköping : Univ, 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/tek857s.pdf.
25
D'Iverno, Mark Paul. "Social agency : a formal computational model." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300509.
26
Bowker, Timothy J. "A computational model for thrombus prediction." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558527.
Анотація:
The haemostatic system stops the loss of blood, thereby maintaining the integrity of the circulatory network. Whilst haemostasis is necessary for survival, thrombosis - haemostasis in the wrong place - is the most common cause of mortality in the West. The presence of a thrombus is governed by the triad of endothelial injury, blood constitution and flow. The central protein involved in this process is thrombin which is formed through a reaction network known as the coagulation cascade. Cerebral saccular aneurysms are balloon like dilations of the cerebral vasculature that are estimated to be present in 2-6% of the population. The currently preferred treatment method for such aneurysms is the deliberate initiation of thrombus formation (leading to occlusion) through the placement of platinum coils within the aneurysm. An emerging alternative is the use of a stent which is deployed across the aneurysm neck, reducing the rate at which flow enters the aneurysm, leading again to the controlled formation of a thrombus. A comprehensive model of thrombus formation within cerebral aneurysms should simulate the reduction to flow as the thrombus grows within the aneurysm. The model must capture the spatial and temporal regulators of thrombus formation - incorporating both biological and mechanical factors. This first part of this thesis examines the sensitivity of flow conditions within cerebral aneurysms to changes in boundary conditions (simulated exercise) and geometrical changes (stent placement). The main contribution of this thesis is the development of frameworks which enable examination of thrombus formation. First, an idealised arteriole is used to examine the impact of flow upon two approaches to computational modelling of thrombin generation. The second framework uses the Level Set technique to track the position of a thrombus surface within a patient specific aneurysmal geometry.
27
Oberholtzer, Josiah W. "A Computational Model of Music Composition." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17463123.
Анотація:
This thesis documents my research into formalized score control, in order to demonstrate a computational model of music composition. When working computationally, models provide an explicit formal description of what objects exist within a given domain, how they behave, and what transformations they afford. The clearer the model becomes, the easier it is to extend and to construct increasingly higher-order abstractions around that model. In other words, a clear computational model of music notation affords the development of a clear model of music composition. The Abjad API for Formalized Score Control, an open-source software library written in the Python programming language and making use of the LilyPond automated typesetting system for graphical output, is presented as such a computational model of music notation. My own compositional modeling work, extending Abjad, is introduced and analyzed in the Python library Consort. A collection of five scores, each implemented as Python packages extending these software libraries, are included. Three of these scores, "Zaira," "Armilla" and "Ersilia," rely on Consort as their compositional engine, and are presented along with their complete sources. These scores demonstrate my development as a composer investigating the role of computation in music, and display a variety of large-scale structures and musical textures made possible when working with such modeling tools.Music
28
McGarrity, Sarah. "A computational model of thiopurine metabolism." Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2963.
Анотація:
A computational model of thiopurine metabolism The thiopurines, azathioprine, mercaptopurine (MP) and thioguanine are used as immunosuppressants and in the treatment of leukaemia. These drugs undergo extensive metabolism to form their cytotoxic metabolites that correlate with drug efficacy and the likelihood of side effects. Although these inexpensive drugs are effective in many patients, a deeper understanding of thiopurine metabolism would enable better individualisation of therapy resulting in increased efficacy and safety. A computational model of MP metabolism using data generated from mercaptopurine treated MOLT-4 (human T-ALL cell line) by a novel liquid chromatography mass spectrometry assay was built in CoPaSi. The model qualitatively reproduced published data about the effects of changes in thiopurine methyltransferase activity on MP metabolism. In vitro studies showed that high concentrations of allopurinol, a xanthine oxidase inhibitor, reduced the sensitivity of MOLT-4 cells to MP from 2.9 μM to 43 μM (P<0.001), whereas lower concentrations of allopurinol slightly but not significantly increased the sensitivity of MOLT-4 cells to MP. Combination of MP and allopurinol treatment of MOLT-4 cells resulted in lower concentrations of thioguanine nucleotides and methylated thioinosine monophosphate metabolites compared to MP only treatment, as determined by liquid chromatography mass spectrometry. These data were used to extend the model of MP metabolism to test hypotheses that addition of allopurinol decreased methylated thioinosine monophosphate and increased the concentration of TGNs. The computational model suggested that the mechanism by which allopurinol interacts with MP metabolism is by inhibiting hypoxanthine guanine phosphoribosyl transferase resulting in altered levels of MeTIMP and TGNs.
29
Chilukamari, Jayachandra. "A computational model of visual attention." Thesis, Robert Gordon University, 2017. http://hdl.handle.net/10059/2443.
Анотація:
Visual attention is a process by which the Human Visual System (HVS) selects most important information from a scene. Visual attention models are computational or mathematical models developed to predict this information. The performance of the state-of-the-art visual attention models is limited in terms of prediction accuracy and computational complexity. In spite of significant amount of active research in this area, modelling visual attention is still an open research challenge. This thesis proposes a novel computational model of visual attention that achieves higher prediction accuracy with low computational complexity. A new bottom-up visual attention model based on in-focus regions is proposed. To develop the model, an image dataset is created by capturing images with in-focus and out-of-focus regions. The Discrete Cosine Transform (DCT) spectrum of these images is investigated qualitatively and quantitatively to discover the key frequency coefficients that correspond to the in-focus regions. The model detects these key coefficients by formulating a novel relation between the in-focus and out-of-focus regions in the frequency domain. These frequency coefficients are used to detect the salient in-focus regions. The simulation results show that this attention model achieves good prediction accuracy with low complexity. The prediction accuracy of the proposed in-focus visual attention model is further improved by incorporating sensitivity of the HVS towards the image centre and the human faces. Moreover, the computational complexity is further reduced by using Integer Cosine Transform (ICT). The model is parameter tuned using the hill climbing approach to optimise the accuracy. The performance has been analysed qualitatively and quantitatively using two large image datasets with eye tracking fixation ground truth. The results show that the model achieves higher prediction accuracy with a lower computational complexity compared to the state-of-the-art visual attention models. The proposed model is useful in predicting human fixations in computationally constrained environments. Mainly it is useful in applications such as perceptual video coding, image quality assessment, object recognition and image segmentation.
30
Martin, Keith Dana. "A computational model of spatial hearing." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36573.
Анотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 60-62).
by Keith Dana Martin.
M.S.
31
De, Biswas Kaustuv Kanti. "A computational model of visual interpretation." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35129.
Анотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2006.Includes bibliographical references (leaves 48-50).
From the very early phases of design conception, designers use sketches as a powerful design tool. Sketches are however ambiguous. Meanings are associated on fly as the designer 'comes up' with certain ideas while working with it. There is no hierarchy in a sketch. In fact 'structure' is established only after meanings are applied to the sketch. However even in such structurally and conceptually fluid territory, the designer solves most of his design problems and very often comes to quick resolutions. To understand this fascinating tool and how the designer interacts with it, we need to understand how we visually interpret sketches. The process of design is also a reflective act. The designer keeps changing his perspectives and focus based on the unexpected opportunities that emerge from such reflection. Computational systems used today in design exploration are not capable of doing so. On the contrary these systems model the world in a very rigid structured way and cannot produce design ideas beyond what their preset description anticipates.
(cont.) From this perspective there is no novelty, or surprise, in such systems. As a step forward, this thesis proposes the following: 1. Visual Schemas as procedural units of visual memory. They schematically store real world knowledge (courtyard) and form the basis for interpretation. 2. Separation of Shape and Visual Concepts. This thesis suggests that shapes are flat and abstract collection of parts, while visual concepts are subjective and hierarchic ideas, which are formed from the shapes through interpretation. A LISP machine is presented as a basic computational framework for implementing and establishing the model that is proposed. It observes a relatively simple architectural sketch, interprets it reflectively through the activation of potential, alternative contexts, and then gives a collection of concepts that it manages to 'see' in the sketch.
by Kaustuv Kanti de Biswas.
S.M.
32
Boucaud, Fabien. "Un agent touchant : modélisation du toucher social dans les interactions humain-agent en environnement immersif." Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2666.
Анотація:
Malgré la puissance de nos technologies de communication actuelles pour maintenir du contact social dans des situations extrêmes, elles restent insuffisantes pour totalement combler les sentiments de solitude et d'isolement. Le toucher social, est essentiel au bien-être humain, nous permet de développer et raffermir nos liens relationnels et est un puissant canal de communication des émotions. Le présent travail de thèse s'intéresse à la façon dont on peut munir des agents artificiels de capacités de toucher social. Qu'il s'agisse de robots ou de personnages virtuels, ces nouvelles entités sociales sont déjà équipées de nombreuses modalités d'interaction (paroles, gestes, expressions faciales, etc.), et munir ces nouveaux types d’entités sociales de capacités de toucher pourrait améliorer encore leurs capacités émotionnelles et relationnelles. Plus particulièrement, notre principale question de recherche est de déterminer quand et comment toucher u and allowsn humain de manière utile, autonome et respectueuse. A cet effet, nous proposons une structure théorique et une implémentation fonctionnelle d'un agent touchant capable d'interagir dynamiquement avec un humain en temps réel, au sein d'un environnement immersif. En particulier, nous décrivons un module de perception des comportements de l'humain, un modèle de décision qui prenne en compte la cohérence et l'acceptabilité du toucher en contexte, et une interface haptique SOFTLY qui puisse être utilisée en immersion dans un environnement virtuel. Les évaluations de ces développements mettent en lumière les capacités prometteuses de ce framework, ainsi que ses limites actuelles et perspectives d'amélioration pour des travaux futursDespite the current abilities of our communication technologies, they remain unable to completely counterbalance feelings of isolation and loneliness. Social touch is essential to human well-being and allows us to develop and strenghten our relationships. It is also powerful channel of emotional communication. This thesis work is aimed at endowing artificial agents with social touch abilities. Whether they are robotic or virtual artificial agents represent new kinds of social entities and are already equipped with many interactional modalities (speech, gestures, facial expressions, etc.). Endowing them with touching abilities could further enhance their abilities to communicate emotions and to bond with humans. More specifically, our main research question is to determine when and how to touch a human is meaningful, autonomous and respectful way. To answer this question, we propose a theoretical structure and a functional implementation of a touching agent, able to dynamically interact with a human in real-time in an immersive environment. We describe a perception module to detect the human’s behaviour, a decision model able to take coherence and acceptability of touch into account, and a haptic interface (SOFTLY) that can be used in the immersive setup to generate haptic feedback. Evaluations of this framework are discussed and hightlight that its abilities are promising, althought there are still clear avenues of improvement for the model
33
Yako, Mary. "Emotional Content in Novels for Literary Genre Prediction : And Impact of Feature Selection on Text Classification Models." Thesis, Uppsala universitet, Institutionen för lingvistik och filologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447148.
Анотація:
Automatic literary genre classification presents a challenging task for Natural Language Processing (NLP) systems, mainly because literary texts have deeper levels of meanings, hold distinctive themes, and communicate certain messages and emotions. We conduct a study where we experiment with building literary genre classifiers based on emotions in novels, to investigate the effects that features pertinent to emotions have on models of genre prediction. We begin by performing an analysis of emotions describing emotional composition and density in the dataset. The experiments are carried out on a dataset consisting of novels categorized in eight different genres. Genre prediction models are built using three algorithms: Random Forest, Support Vector Machine, and k-Nearest Neighbor. We build models based on emotion-words counts and emotional words in a novel, and compare them to models of commonly used features, the bag-of-words and the TF-IDF features. Moreover, we use a feature selection dimensionality reduction procedure on the TF-IDF feature set and study its impact on classification performance. Finally, we train and test the classifiers on a combination of the two most optimal emotion-related feature sets, and compare them on classifiers trained and tested on a combination of bag-of-words and the reduced TF-IDF features. Our results confirm that: using features of emotional content in novels improves classification performance a 75% F1 compared to a bag-of-words baseline of 71% F1; TF-IDF feature filtering method positively impacts genre classification performance on literary texts.
34
Scibilia, Francesco. "Explicit Model Predictive Control:Solutions Via Computational Geometry." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11627.
Анотація:
The thesis is mainly focused on issues involved with explicit model predictive control approaches. Conventional model predictive control (MPC) implementation requires at each sampling time the solution of an open-loop optimal control problem with the current state as the initial condition of the optimization. Formulating the MPC problem as a multi-parametric programming problem, the online optimization effort can be moved offline and the optimal control law given as an explicitly defined piecewise affine (PWA) function with dependence on the current state. The domain where the PWA function is defined corresponds to the feasible set which is partitioned into convex regions. This makes explicit MPC solutions into promising approaches to extend the scope of applicability of MPC schemes. The online computation reduces to simple evaluations of a PWA function, allowing implementations on simple hardware and with fast sampling rates. Furthermore, the closed form of the MPC solutions allows offline analysis of the performance, providing additional insight of the controller behavior. However, explicit MPC implementations may still be prohibitively costly for large optimization problems. The offline computational effort needed to solve the multiparametric optimization problem may be discouraging, and even the online computation needed to evaluate a complex PWA controller may cause difficulties if low-cost hardware is used. The first contribution of this thesis is to propose a technique for computing approximate explicit MPC solutions for the cases where optimal explicit MPC solutions are impractical due to the offline computational effort needed and their complexity for online evaluations. This technique is based on computational geometry, a branch of computer science which focuses heavily on computational complexity since the algorithms are intended to be used on large data-sets. The approximate solution is suboptimal only over the subregion of the feasible set where constraints are active. In this subregion, the ineffective optimal explicit MPC solution is replaced by an approximation based on Delaunay tessellations and is computed from a finite number of samples of the exact solution. Finer tessellations can be obtained in order to achieve a desired level of accuracy Successively, the thesis presents a twofold contribution concerned with the computation of feasible sets for MPC and their suitable approximations. First, an alternative approach is suggested for computing the feasible set which uses set relations instead of the conventional orthogonal projection. The approach can be implemented incrementally on the length of the MPC prediction horizon, and proves to be computationally less demanding than the standard approach. Thereafter, an algorithm for computing suitable inner approximations of the feasible set is proposed, which constitutes the main contribution. Such approximations are characterized by simpler representations and preserve the essential properties of the feasible set as convexity, positive invariance, inclusion of the set of expected initial states. This contribution is particularly important in the context of finding less complex suboptimal explicit MPC solutions, where the complexity of the feasible set plays a decisive role. The last part of the thesis is concerned with robustness of nominal explicit MPC solutions to model uncertainty. In the presence of model mismatch, when the controller designed using the nominal model is applied to the real plant, the feasible set may lose its invariance property, and this means violation of constraints. Also, since the PWA control law is designed only over the feasible set, there is the technical problem that the control action is undefined if the state moves outside of this set. To deal with this issue, a tool is proposed to analyze how uncertainty on the model affects the PWA control law computed using the nominal model. Given the linear system describing the plant and the PWA control law, the algorithm presented considers the polytopic model uncertainty and constructs the maximal robust feasible set, i.e. the largest subset of the feasible set which is guaranteed to be feasible for any model in the family of models described by the polytopic uncertainty. The appendix of the thesis contains two additional contributions which are only marginally related to the main theme of the thesis. MPC approaches are often implemented as state feedback controllers. The state variables are not always measured, and in these cases a state estimation approach has to be adopted to obtain the state from the measurements. The two contributions deal with state estimation in two different applications, but not with the explicit goal of being used in MPC approaches.
35
Silva, Araujo Monteiro Virginia. "Computational model of the human urinary bladder." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/128923.
Анотація:
La propuesta de una vejiga artificial es un obstáculo a trasponer. El cáncer de vejiga está entre los casos más frecuentes de enfermedades oncológicas en Estados Unidos y Europa. Ese cáncer es considerado un problema médico importante una vez que esa enfermedad presenta altas tasas de re-ocurrencia, muchas veces llevando a la remoción del órgano. La solución más sofisticada para remplazar ese órgano es la vejiga ileal, que consiste en una neovejiga hecha de tejido intestinal del enfermo. Desafortunadamente, esa solución presenta no solo problemas mecánicos funcionales, descritos en la literatura como problemas de vaciado y fuga, peo también problemas de orden biológica (como ejemplo pérdida ósea, debido a la absorción por el intestino de substancias que necesitan ser eliminadas del organismo).
A través de la solicitación de la comunidad urológica del Hospital Clínico de Barcelona y con su experiencia en modelos numéricos para estructuras biomédicas, el Centro de Métodos Numéricos en Ingeniería (CIMNE) ha tenido la iniciativa de proporcionar actividad investigadora de la mecánica de la vejiga urinaria y de la simulación de interacción fluidoestructura para reproducir el llenado y vaciado de ese órgano con la orina.
La simulación de la vejiga humana por el Método de los Elementos Finitos (FEM) y un completo entendimiento de la mecánica de ese órgano y de su interacción con la orina dará la posibilidad de proponer mejora en la geometría y de analizar materiales para la solución artificial en caso de remplazamiento de la vejiga. Para lograr ese objetivo, primeramente procedemos a una revisión bibliográfica de los modelos matemáticos del aparato urinario y un estudio comprehensivo de la fisiología y dinámica de la vejiga. Presentamos una revisión de las principales estructuras urológicas, riñón, uréter y uretra. Las estructuras anexas también son consideradas para entender las condiciones de contorno del problema estudiado.
Posteriormente, proponemos el modelo constitutivo para estudiar la vejiga urinaria humana. El comportamiento del musculo detrusor durante llenado y vaciado de la vejiga con orina, su habilidad de retención de orina a baja presión debe ser correctamente representada por medio
de la implementación de un modelo constitutivo no-lineal. El modelo matemático necesita representar las variables mecánicas que gobiernan ese órgano, y también las propiedades de la orina. El comportamiento no-lineal de tejidos vivos es implementado y validado con ejemplos de
la literatura. La propiedad quasi-incompressible de la orina y las ecuaciones Navier-Stokes son consideradas para análisis del fluido.
Para representar la geometría de la vejiga, implementamos un modelo computacional 3D a partir de imágenes de tomografía computadorizada de un cadáver adulto. Los datos son tratados para considerar las condiciones de contorno. Hemos construido dos modelos de malla: un
mallado con tetrahedos de cuatro nodos y otro mallado con elementos de membrana de tres nodos.
El esquema utilizado para calcular la interacción fluido-estructura debe ser adecuado para materiales de densidad muy parecidas. El análisis numérico de llenado y vaciado de la vejiga humana es validada con tests urodinámicos estandarizados. La parte final de la tesis, presentamos una simulación de una neo-vejiga, siendo el primer paso para representar numéricamente materiales artificiales para remplazamiento de la vejiga.The proposal of an artificial bladder is still a challenge to overcome. Bladder cancer is among the most frequent cases of oncologic diseases in United States and Europe. It is considered a major medical problem once this disease has high rates of reoccurrence, often leading to the extirpation of this organ. The most refined solution to replace this organ is the ileal bladder, which consists of a neobladder made of the patient’s intestinal tissue. Unfortunately this solution presents not only functional mechanical problems, described on the literature as voiding and leaking problems, but also biological ones (i.e. bone loss, given the absorption by the intestine of substances that should be eliminated from the organism). Urged by the urological community of the Hospital Clinic de Barcelona and backgrounded by its experience in the numerical simulation of biomedical structures, the Center of Numerical Methods in Engineering (CIMNE) had the initiative to provide the research of the mechanics of the urinary bladder and the simulation of fluid structure interaction (FSI) to account for the filling and voiding of this organ with urine. The Finite Element Method (FEM) simulation of the real bladder and the comprehensive understanding of the mechanics of this organ and its interaction with urine will give the possibility to propose geometrical improvements and study suitable materials for an artificial solution to address the cases on which the bladder needs to be removed. To reach this goal, first we proceeded to the bibliographic review of mathematical models of the urinary apparatus and to a comprehensive study of the physiology and dynamics of the bladder. A review of the major urological structures, kidney, ureter and urethra, takes place. To consider boundary conditions other surrounding structures to the urinary system are also studied. In the second part of the thesis, we propose the numerical model to study the human urinary bladder. The behavior of the detrusor muscle during filling and voiding of the bladder with urine and its ability to promote the storage of urine under low pressure need to be accurately represented, requiring the implementation of a non-linear constitutive model. The mathematical model needs to be capable to simulate the mechanical variables that govern this organ and the properties of the urine. The nonlinear behavior of living tissues is implemented and validated with examples from the literature. The quasi-incompressibility property of urine and the navierstokes equations for the fluid are taken into account. The geometry of the bladder needs to be taken into account, and the implementation of a 3D computational model obtained from the computerized tomography of a cadaver male adult is considered. The data has been treated to consider boundary conditions. Two models have been conceived: one meshed with four nodes tetrahedral and another meshed with shell elements. FSI must work for the simulation of filling and voiding of the bladder. Due to the close densities of the materials the scheme used to solve fluid-structure needs to be carefully selected. The proposed numerical model and the filling and voiding analysis are finally validated with standardized urodynamic tests. The final part of the thesis, the simulation of a neobladder is presented, being the first step to simulate numerically artificial materials for bladder replacement.
36
Benavente, Vidal Robert. "A Parametric Model for Computational Colour Naming." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/5781.
Анотація:
El color és una font d'informació visual molt important i àmpliament utilitzada en els darrers anys en la visió per computador. La majoria dels mètodes desenvolupats fins ara tenen com objectiu extreure característiques de baix nivell de les imatges i aquesta informació no té un lligam directe amb la semàntica d'alt nivell que utilitzem els humans. La falta d'aquesta relació directa, que es coneix com -semantic gap', és encara més significativa per algunes aplicacions com la recuperació d'imatges de bases de dades on els usuaris requereixen sistemes que permetin realitzar cerques en llenguatge natural o almenys en un llenguatge d'alt nivell. Per tant, el principal objectiu d'aquesta tesi és fer un avanç en la línia de reduir el -semantic gap' en la tasca de donar noms als colors de les imatges.La principal contribució d'aquesta tesi és un model paramètric d'assignació de noms de colors en imatges. El problema s'ha emmarcat en la teoria dels conjunts difusos en la que cadascuna de les 11 categories bàsiques de color (blanc, negre, vermell, verd,
groc, blau, marró, morat, rosa, taronja i gris) està caracteritzada per una funció de pertinença.
Donat que l'objectiu d'aquest model és obtenir els mateixos noms que proporcionaria un observador humà, es necessita un conjunt de judicis fets per persones com a punt de partida pel procés de modelat. Per obtenir aquest conjunt de dades es proposa una metodologia basada en lògica difusa per experiments psicofísics que ha permès obtenir un conjunt de judicis difusos. La metodologia i els resultats són validats a partir del càlcul d'alguns estadístics habituals que són comparats amb experiments previs per mostrar l'equivalència entre els resultats obtinguts amb la nova metodologia i els d'experiments anteriors. El conjunt de dades obtingut s'ha posat a disposició de la comunitat científica a través d'Internet.
L'anàlisi dels resultats de l'experiment permet definir les propietats que les funcions de pertinença haurien de complir. Proposarem i avaluarem diverses funcions per arribar finalment al model Triple Sigmoid amb centre El·líptic (TSE) que proporciona un bon ajust al conjunt d'aprenentatge i una classificació de l'espai de color Munsell que és consistent amb els treballs previs. El resultat del procés d'ajust és el conjunt de paràmetres del model que permeten calcular la pertinença de qualsevol mostra de color a les 11 categories de color considerades, amb tots els avantatges d'una implementació paramètrica.
La darrera part de la tesi està dedicada a l'anàlisi de les condicions necessàries per aplicar el model en imatges reals sota condicions no calibrades on no es coneix cap informació sobre les condicions d'adquisició. Aquesta anàlisi mostra que el model pot funcionar amb un error acceptable en aplicacions de visió per computador en les que és necessària una representació perceptiva de la informació de color. El model s'avalua en una d'aquestes aplicacions per un problema real d'anotació automàtica de bases de dades d'imatges. Els resultats en els experiments mostren la potencialitat del model d'assignació de noms de color per diferents aplicacions futures i obren noves possibilitats de recerca en aquest camp.
Colour is an important visual cue widely used in computer vision in the last years. Most of the methods developed so far aim to extract low-level colour features from images and such information do not have a direct link to the high-level semantics that humans use. The lack of this direct link, known as the semantic gap, is even more significant for some applications such as image retrieval where users require systems able to support queries in natural language or, at least, in a high-level language. Hence, the main goal of this thesis is to make a further step in the way of reducing the semantic gap in the task of giving names to colours in images.
The main contribution of this thesis is a parametric colour-naming model for images. The problem is framed on the fuzzy set theory where each one of the 11 basic colour categories (white, black, red, green, yellow, blue, brown, purple, pink, orange, and grey) is characterized by a membership function.
Since the goal of such a model is to obtain the same name assignments as a human observer would provide, a set of human judgements is needed as starting point for the modelling process. To obtain such a data set we propose a methodology for fuzzy psychophysical experiments and a set of fuzzy judgements are obtained. The methodology and the results are validated by computing some usual statistics which are compared to previous experiments to show the equivalence of the results obtained with the new methodology and the ones from former experiments. The data set obtained has been made available online on the Internet for the research community.
The analysis of the results from the experiment allows defining the properties that the membership functions should fulfil. Several functions are proposed and evaluated to achieve the final Triple-Sigmoid with Elliptical centre (TSE) model which provides good fitting to the learning data and a categorization of the Munsell colour space which is consistent with previous works. The result of the fitting process is the set of parameters of the model which allows computing the membership of any given colour sample to the 11 colour categories considered, with all the advantages of a parametric implementation.
The last part of the thesis is devoted to analyse the conditions needed to apply the model on real images under uncalibrated conditions where no information about the acquisition conditions is known. This analysis shows that the model can work with an acceptable error on computer vision applications where a perceptual representation of colour information is needed. The model is tested in one of these applications on a real problem where automatic image annotation is used for image retrieval. The results on the experiments show the potentiality of the colour-naming model for different future applications and open new research possibilities in this field.
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Struckmeier, Vera. "A computational model for seismically induced liquefaction." Braunschweig Mechanik-Zentrum der Techn. Univ, 2007. http://d-nb.info/997386584/34.
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Heller, Collin M. "A computational model of engineering decision making." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50272.
Анотація:
The research objective of this thesis is to formulate and demonstrate a computational framework for modeling the design decisions of engineers. This framework is intended to be descriptive in nature as opposed to prescriptive or normative; the output of the model represents a plausible result of a designer's decision making process. The framework decomposes the decision into three elements: the problem statement, the designer's beliefs about the alternatives, and the designer's preferences. Multi-attribute utility theory is used to capture designer preferences for multiple objectives under uncertainty. Machine-learning techniques are used to store the designer's knowledge and to make Bayesian inferences regarding the attributes of alternatives. These models are integrated into the framework of a Markov decision process to simulate multiple sequential decisions. The overall framework enables the designer's decision problem to be transformed into an optimization problem statement; the simulated designer selects the alternative with the maximum expected utility. Although utility theory is typically viewed as a normative decision framework, the perspective in this research is that the approach can be used in a descriptive context for modeling rational and non-time critical decisions by engineering designers. This approach is intended to enable the formalisms of utility theory to be used to design human subjects experiments involving engineers in design organizations based on pairwise lotteries and other methods for preference elicitation. The results of these experiments would substantiate the selection of parameters in the model to enable it to be used to diagnose potential problems in engineering design projects.
The purpose of the decision-making framework is to enable the development of a design process simulation of an organization involved in the development of a large-scale complex engineered system such as an aircraft or spacecraft. The decision model will allow researchers to determine the broader effects of individual engineering decisions on the aggregate dynamics of the design process and the resulting performance of the designed artifact itself. To illustrate the model's applicability in this context, the framework is demonstrated on three example problems: a one-dimensional decision problem, a multidimensional turbojet design problem, and a variable fidelity analysis problem. Individual utility functions are developed for designers in a requirements-driven design problem and then combined into a multi-attribute utility function. Gaussian process models are used to represent the designer's beliefs about the alternatives, and a custom covariance function is formulated to more accurately represent a designer's uncertainty in beliefs about the design attributes.
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Heiberg, Andrea Jeanine. "Features in optimality theory: A computational model." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/288983.
Анотація:
This dissertation presents a computational model of Optimality Theory (OT) (Prince and Smolensky 1993). The model provides an efficient solution to the problem of candidate generation and evaluation, and is demonstrated for the realm of phonological features. Explicit object-oriented implementations are proposed for autosegmental representations (Goldsmith 1976 and many others) and violable OT constraints and Gen operations on autosegmental representations. Previous computational models of OT (Ellison 1995, Tesar 1995, Eisner 1997, Hammond 1997, Karttunen 1998) have not dealt in depth with autosegmental representations. The proposed model provides a full treatment of autosegmental representations and constraints on autosegmental representations (Akinlabi 1996, Archangeli and Pulleyblank 1994, Ito, Mester, and Padgett 1995, Kirchner 1993, Padgett 1995, Pulleyblank 1993, 1996, 1998). Implementing Gen, the candidate generation component of OT, is a seemingly intractable problem. Gen in principle performs unlimited insertion; therefore, it may produce an infinite candidate set. For autosegmental representations, however, it is not necessary to think of Gen as infinite. The Obligatory Contour Principle (Leben 1973, McCarthy 1979, 1986) restricts the number of tokens of any one feature type in a single representation; hence, Gen for autosegmental features is finite. However, a finite Gen may produce a candidate set of exponential size. Consider an input representation with four anchors for each of five features: there are (2⁴ + 1)⁵, more than one million, candidates for such an input. The proposed model implements a method for significantly reducing the exponential size of the candidate set. Instead of first creating all candidates (Gen) and then evaluating them against the constraint hierarchy (Eval), candidate creation and evaluation are interleaved (cf. Eisner 1997, Hammond 1997) in a Gen-Eval loop. At each pass through the Gen-Eval loop, Gen operations apply to create the minimal number of candidates needed for constraint evaluation; this candidate set is evaluated and culled, and the set of Gen operations is reduced. The loop continues until the hierarchy is exhausted; the remaining candidate(s) are optimal. In providing explicit implementations of autosegmental representations, constraints, and Gen operations, the model provides a coherent view of autosegmental theory, Optimality Theory, and the interaction between the two.
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Lee, KangWoo. "Computational model of visual attention : integrative approach." Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289231.
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McElhone, Charles Gerard. "A constrained computational model for flexible scheduling." Thesis, University of York, 1996. http://etheses.whiterose.ac.uk/10900/.
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Ribeiro, Paulo Justiniano. "Model based geostatistics, applications and computational implementation." Thesis, Lancaster University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418853.
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Chuang, Wei Kuo. "Computational model for engineering design and development." Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263496.
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Elliot, Mark James. "A computational model of task oriented discourse." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284055.
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Follett, Stephen James. "A computational model of learning in Go." Thesis, University of South Wales, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343412.
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Szumski, Ronald. "A new computational model for optical analysis." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299480.
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Gartenberg, Daniel. "A Comprehensive Computational Model of Sustained Attention." Thesis, George Mason University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10130797.
Анотація:
The vigilance decrement is the decline in performance over time that characterizes tasks requiring sustained attention. Resource Theory proposes that the vigilance decrement is due to information processing assets that become depleted with use. Resource theorists must thus identify these assets and the process of how resources are depleted and replenished. The Microlapse Theory of Fatigue (MTF) identifies the resource that is depleted when performing a sustained attention task as the central executive attentional network. The depletion of the central executive network resource results in microlapses or brief gaps in attention that prevent the perception and processing of information. The MTF can explain various effects in the sustained attention literature regarding how resources are depleted. However, the MTF alone cannot explain the event rate effect or the motivation effect because it does not include replenishment mechanisms that can occur during a sustained attention task. To better understand the process of replenishment, participants were assigned to varying event rate and external motivation conditions in a novel paradigm that could measure the perceptual processing of a trial over time. These stages of processing included when participants looked at the first stimulus, looked at the second stimulus, and responded. In Experiment 1, it was found that the vigilance decrement was more severe for faster event rates, consistent with Resource Theory and counter to the MTF. In Experiment 2, the event rate effect was replicated, but unexpectedly, external motivation did not impact the vigilance decrement. In both experiments it was found that for the stages of processing that involved looking at the stimuli, more slowing was found as event rate increased. Additionally, more slowing was detected earlier in the processing of a trial than later. These results supported the process of microlapses inducing the vigilance decrement due to not having enough time to perceive, encode, and respond to stimuli, as described by the MTF. It was interpreted that the interaction between time-on-task and event rate was due to opportunistic breaks that occurred more frequently in slower event rate conditions. The finding that more slowing occurred earlier in processing was interpreted as evidence for internal rewards related to learning impacting the speed of processing a trial. To explain these findings, I propose the Microlapse Theory of Fatigue with Replenishment (MTFR) a process model similar to MTF, but that includes additional replenishment mechanisms related to opportunistic rest periods and internal rewards. The Microlapse Theory of Fatigue with Replenishment (MTFR) closely correlates to the empirical data and is an important step forward in the effort to build a comprehensive model of sustained attention.
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Ziehm, Matthias Fritz. "Computational biology of longevity in model organisms." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648888.
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Mitchell, Simon. "A computational model of human iron metabolism." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/a-computational-model-of-human-iron-metabolism(c3afe167-4a40-42aa-8fd8-a65e47dfe7eb).html.
Анотація:
Iron is essential for virtually all organisms, yet it can be highly toxic if not properly regulated. Only the Lyme disease pathogen Borrelia burgdorferi has evolved to not require iron (Aguirre et al., 2013).Recent findings have characterised elements of the iron metabolism network, but understanding of systemic iron regulation remains poor. To improve understanding and provide a tool for in silico experimentation, a computational model of human iron metabolism has been constructed. COPASI was utilised to construct a model that included detailed modelling of iron metabolism in liver and intestinal cells. Inter-cellular interactions and dietary iron absorption were included to create a systemic computational model. Parameterisation was performed using a wide variety of literature data. Validation of the model was performed using published experimental and clinical findings, and the model was found to recreate quantitatively and accurately many results. Analysis of sensitivities in the model showed that, despite enterocytes being the only route of iron uptake, almost all control over the system is provided by reactions in the liver. Metabolic control analysis identified key regulatory factors and potential therapeutic targets. A virtual haemochromatosis patient was created and compared to a simulation of a healthy human. The redistribution of control in haemochromatosis was analysed in order to improve our understanding of the condition and identify promising therapeutic targets. Cellular prion protein (PrP) is an enigmatic protein, implicated in disease when misfolded, but its physiological role remains a mystery. PrP was recently found to have ferric-reductase capacity. Potential sites of ferric reduction were simulated and the findings compared to PrP knockout mice experiments. I propose that the physiological role of PrP is in the chemical reduction of endocytosed ferric iron to its ferrous form following transferrin receptor-mediated uptake.
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Martinez, Baca Velasco Carlos. "Computational model of a PEM fuel cell." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/11519.