Дисертації з теми "Computer experimental analysis"
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Kang, Lulu. "Computer and physical experiments: design, modeling, and multivariate interpolation." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34805.
Повний текст джерелаKharechko, Andriy. "Linear and ellipsoidal pattern separation : theoretical aspects and experimental analysis." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/195011/.
Повний текст джерелаWoods, Duncan E. "The experimental analysis and computer simulation of bielectrical referencing systems." Thesis, University of Surrey, 1994. http://epubs.surrey.ac.uk/843128/.
Повний текст джерелаWood, Duncan E. "The experimental analysis and computer simulation of bioelectric referencing systems." Thesis, University of Surrey, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308638.
Повний текст джерелаHoeke, Marilynn Carol. "A computer instructional support environment for information literacy: An experimental analysis." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184375.
Повний текст джерелаBoulos, Emile T. "Experimental Analysis of Probabilistic Smart Terrain in Unity." Youngstown State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525432760403556.
Повний текст джерелаBrubaker, Briana. "Experimental Evaluation and Computer Analysis of Multi-Spiral Confinement in Reinforced Concrete Columns." Kansas State University, 2017. http://hdl.handle.net/2097/35324.
Повний текст джерелаDepartment of Civil Engineering
Asadollah Esmaeily
Bridge and building construction in areas that sustain frequent seismic activity require the use of heavy lateral steel reinforcement within concrete columns to handle the lateral loads. Multi-spiral lateral reinforcement has been recently introduced to the construction field to offer an alternative to the traditional hoop and tie reinforcement. This report evaluates the experimental data observed in multiple experimental studies done on different concrete specimens. These specimens include multiple rectilinear reinforcement and several multi-spiral configurations in both rectangular and oblong columns. Due to multi-spiral reinforcement being a relatively new design, traditional computer programs have yet to include design analysis for this type of reinforcement in computer programs. Dr. Asad Esmaeily developed the program KSU RC 2.0 that can implement multiple analytical models to evaluate different multi-spiral configurations, as well as traditional hoop and tie confinement, that may be compared with experimental data. This report illustrates the comparative data from several different reinforced concrete column models. The data clearly indicates that multi-spiral reinforced columns exhibit higher compressive strength in the axial direction as well as higher ductility capabilities when compared to traditional rectilinear reinforcement of similar lateral steel reinforcement ratios. The use of multi-spiral reinforcement is also shown to lower costs for both the work time needed to install the structures as well as lowering the required steel ratio; all while maintaining the structural integrity of the columns.
Sahama, Tony. "Some practical issues in the design and analysis of computer experiments." Thesis, Victoria University, Melbourne, 2003. https://eprints.qut.edu.au/60715/1/Sahama_2003compressed.pdf.
Повний текст джерелаMuthitacharoen, Athicha 1976. "An experimental analysis of exception handling services for multi-agent systems." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86529.
Повний текст джерелаIncludes bibliographical references (leaves 43-45).
by Athicha Muthitacharoen.
S.B.and M.Eng.
Hung, Ying. "Contributions to computer experiments and binary time series." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24707.
Повний текст джерелаCommittee Chair: C. F. Jeff Wu; Committee Co-Chair: Roshan Joseph Vengazhiyil; Committee Member: Kwok L. Tsui; Committee Member: Ming Yuan; Committee Member: Shreyes N. Melkote
Duncan, Tyler Baxter. "Theoretical analysis and experimental investigation of a "tower" heat pipe for desktop computer cooling /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426054.
Повний текст джерелаPapaioannou, Ioannis. "Theoretical and experimental analysis for optimizing the performance of a SLPP." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63388.
Повний текст джерелаKiraly, Bret D. "An Experimental Application of Formal Concept Analysis to Research Communities." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1228497076.
Повний текст джерелаGanatra, Nirmal Kirtikumar. "Validation of computer-generated results with experimental data obtained for torsional vibration of synchronous motor-driven turbomachinery." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/499.
Повний текст джерелаRamos-Murguialday, Ander [Verfasser], and Niels [Akademischer Betreuer] Birbaumer. "Afferent effects on brain computer interfaces : an experimental analysis / Ander Ramos-Murguialday ; Betreuer: Niels Birbaumer." Tübingen : Universitätsbibliothek Tübingen, 2011. http://d-nb.info/1161735232/34.
Повний текст джерелаZhang, Yulei. "Computer Experiments with Both Quantitative and Qualitative Inputs." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408042133.
Повний текст джерелаAdiga, Nagesh. "Contributions to variable selection for mean modeling and variance modeling in computer experiments." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43592.
Повний текст джерелаChaaban, Farid B. "Computer aided analysis, modelling and experimental assessment of permanent magnet synchronous machines with rare earth magnets." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293710.
Повний текст джерелаWu, Sichao. "Computational Framework for Uncertainty Quantification, Sensitivity Analysis and Experimental Design of Network-based Computer Simulation Models." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78764.
Повний текст джерелаPh. D.
Lasisi, Ramoni Olaoluwa. "Experimental Analysis of the Effects of Manipulations in Weighted Voting Games." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1771.
Повний текст джерелаHenning, Gustav. "Visualization of neural data : Dynamic representation and analysis of accumulated experimental data." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166770.
Повний текст джерелаDen vetenskapliga metoden är en integral del av undersökningen och utforskandet av hypoteser. Medan procedurer varierar mellan fält liknar de varandra i stora drag. Idag finns det ingen brist på verktyg som visualiserar data i olika grafiska kontexter. Istället fokuserar denna tes på de typ av verktyg som forskare använder för att undersöka integriteten av hypoteser. När tillräckligt med data samlats finns det olika sätt att presentera denna på ett meningsfullt sätt för att demonstrera mönster och avvikelser som skulle förbli osedda i endast siffror. Hurvida användbar statisk visualisering av data är som grafik till vetenskapliga rapporter gäller nödvändigtvis inte samma sak vid analys på grund av de många kombinationer av visualisering som ofta finns. Mjukvara kommer att introduceras för att demonstrera behovet av dynamisk representation vid analys av ackumulerad data för att påskynda upptäckten av mönster och avvikelser.
Gounder, James Dakshina. "An experimental investigation of non-reacting and reacting spray jets." Phd thesis, School of Aerospace, Mechanical and Mechatronic Engineering, 2009. http://hdl.handle.net/2123/14424.
Повний текст джерелаSehgal, Rahul. "Greedy routing in a graph by aid of its spanning tree experimental results and analysis /." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1232166476.
Повний текст джерелаSadjadee, Sahand. "Meteor framework, a new approach to webdevelopment: an experimental analysis." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-103802.
Повний текст джерелаLaitakari, J. (Jaakko). "Computer-assisted quantitative image analysis of cell proliferation, angiogenesis and stromal markers in experimental and laryngeal tumor development." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269497.
Повний текст джерелаKamineni, Surya Bharat. "Experimental Analysis on the Feasibility of Voice Based Symmetric Key Generation for Embedded Devices." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6874.
Повний текст джерелаCondict, Nahlah. "EXPERIMENTAL ANALYSIS OF MULTI-PURPOSE UWB RF SYSTEM FOR AD-HOC RADAR SENSOR NETWORK APPLICATIONS." Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1533915320524546.
Повний текст джерелаLiu, Kwong Ip. "Digital net experimental designs, function interpolations using low discrepancy sequence and goodness of fit tests by discrepancy." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/807.
Повний текст джерелаSinclair, James A. "Establishing a New Paradigm in Engineering and Technology education: An Experimental Analysis of Multiple Learning Methodologies and Examination of Cognitive Profiles of Continuing Education Students." NSUWorks, 2006. http://nsuworks.nova.edu/gscis_etd/843.
Повний текст джерелаXie, Huizhi. "Some contributions to latin hypercube design, irregular region smoothing and uncertainty quantification." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44770.
Повний текст джерелаRekanar, Kaavya. "Text Classification of Legitimate and Rogue online Privacy Policies : Manual Analysis and a Machine Learning Experimental Approach." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13363.
Повний текст джерелаMuller, Sandra, and n/a. "Poetics in the digital age : media-specific analysis of experimental poetry on and off the screen." University of Otago. Department of English, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090501.132423.
Повний текст джерелаRothwell, Clayton D. "Recurrence Quantification Models of Human Conversational Grounding Processes: Informing Natural Language Human-Computer Interaction." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1527591081613424.
Повний текст джерелаGiedt, Randy James. "Mitochondrial Network Dynamics in Vascular Endothelial Cells Exposed to Mechanochemical Stimuli: Experimental and Mathematical Analysis." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1333985787.
Повний текст джерелаSilversved, Nicklas, and Hampus Runesson. "A comparison of the security in ZigBee and the IEEE 802.15.9 standard and an experimental analysis of communication over IEEE 802.15.4." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157762.
Повний текст джерелаKim, Yoonhwak. "The Effects of Assumption on Subspace Identification using Simulation and Experiment Data." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5666.
Повний текст джерелаM.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering; Structures and Geotechnical Engineering
Mitchell, John C. "A use-wear analysis of selected British Lower Palaeolithic handaxes with special reference to the site of Boxgrove (West Sussex) : a study incorporating optical microscopy, computer aided image analysis and experimental archaeology." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285553.
Повний текст джерелаRodrigues, Fábio Rodrigo Mandello. "Análise numérica tridimensional e experimental do comportamento mecânico de alças ortodônticas delta." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1012.
Повний текст джерелаThis study analyzed numerically and experimentally the mechanical characteristics of orthodontic springs with delta geometry with and without an upper loop. To our knowledge this kind of study of delta springs without an upper loop has not yet been described in the literature. The material used to make the springs was a titanium-molybdenum alloy commonly used in orthodontic applications. Numerical simulations were performed with finite element modeling (FEM) using three-dimensional elements and large-displacement analysis, unlike the analyses found in the literature to date for this type of spring, which are exclusively two-dimensional. The springs were simulated to reflect a real clinical situation with horizontal activation (in the x direction). In the experimental analysis to determine the reactive forces and moments, a platform with strain gauges mounted on a full Wheatstone bridge whose output voltages corresponded to the strain applied to the spring (the test specimen) was used. The voltage variations were read with the aid of a National Instruments data acquisition system, which, when used with the LabVIEW program, provides voltage values which are converted into forces and moments to calibrate the platform. Each value of force and reactive moment was recorded in a table, from zero activation to the maximum value, i.e., just before the yield strength of the material was reached. In addition to the reactive forces and moments, the moment-to-force ratios (M:F) were measured. According to the literature, these ratios define the type of tooth movement in a clinical case. The results show that the reactive forces along the x-axis in the springs without a loop were greater than in the springs with a loop. In contrast, the reactive intrusive/extrusive forces in the y-axis, which were very small and could be neglected in this study because they had little influence on the results, were similar for both types of spring. A curve showing the change in stress along the spring as a function of activation was plotted. This showed that springs without a loop had higher stresses for a given activation value and therefore a greater tendency to deform plastically. The predominant M:F ratio in this study was the Mz/Fx ratio, which is the moment-to-force ratio that produces most types of tooth movements described in the literature and is to date the only moment-to-force ratio described in the literature for the delta spring. The tooth movements in the xy-plane as a result of the Mz/Fx moment-to-force ratio produced by delta springs with and without a loop are root rotation, crown rotation and translation. Based on the values of My/Fx observed, it can be inferred that this type of spring does not produce any tooth movement in the xz-plane. Another factor that is not explored in the literature but that was considered here is the variation in the angle between the extremities of the spring and its impact on the final forces, moments and M:F ratio.
Pivatto, Amanda Brandenburg. "Análise experimental e computacional de vigas biapoiadas de concreto armado reforçadas com CRFC." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2660.
Повний текст джерелаA falta de manutenção, a mudança de carregamentos, as deficiências de projeto, de execução e até mesmo dos materiais constituintes de uma peça estrutural podem levar à necessidade de aplicação de um reforço estrutural. Dentre estes métodos se destaca o reforço estrutural com Compósitos Reforçados com Fibra de Carbono (CRFC). Este trabalho tem como objetivo analisar o comportamento estrutural por meio de métodos experimentais e modelagem numérica de vigas biapoiadas de concreto armado reforçadas à flexão com CRFC, além de analisar a influência da adição de incrementos de ancoragem no comportamento da peça. O modelo computacional foi desenvolvido no software comercial ANSYS, por meio da utilização do Método dos Elementos Finitos. Foi avaliado o ganho de resistência com a implantação de uma e duas camadas de CRFC em comparação à viga sem reforço. A interface concreto – reforço foi considerada na simulação computacional, uma vez que os esforços atuantes nesta região geralmente são a causa da ruptura neste tipo de peça. Para isso, foi utilizado o Modelo da Zona de Coesão como método de representação da interface. Em relação ao programa experimental, além da variação do número de camadas de reforço, também foi avaliada a influência da adição de incrementos de ancoragem lateral no comportamento das vigas estudadas. Como resultados, foi alcançada uma boa acurácia entre os modelos computacionais e a análise experimental em relação ao valor da carga última de cada situação analisada, bem como em relação ao valor de deslocamento encontrado para as vigas reforçadas. Entretanto, percebeu-se que os valores das deformações obtidos no modelo computacional foram superiores à média dos valores encontrados na análise experimental. Além disso, observou-se também que as vigas tiveram sua rigidez aumentada com o acréscimo de camadas de reforço. Ademais, foi verificado que a adição de incrementos de ancoragem levou a um acréscimo na resistência das peças, mais efetivo que o aumento do número de camadas, para o caso deste trabalho.
The lack of maintenance, the change in loadings, project and execution failures, and even failures of constituent materials of a structural part lead to the necessity of applying a structural reinforcement. Among these methods highlights the structural reinforcement with Carbon Fiber Reinforced Polymer (CFRP). This research has the objective to examine whether there is a good relationship between laboratory tests and a simulation model of reinforced concrete beams strengthened in bending with CFRP, in addition to analyze the influence of anchorage increments application in the structural behavior. The computacional model was developed in the comercial software ANSYS, by the utilization of the Finite Element Modeling for the structural analysis. The resistance gain with the implementation of one and two layers of CFRP was evaluated compared with the reference beam. The concrete – reinforce interface was considered in the computacional simulation, since the active efforts in this area are the reason of this type of structure failure. Thus, the Cohesive Zone Model was used for the interface representation. In relation to the experimental tests, beyond the number of layers variation, it was also evaluated the influence of anchorage increments application in the structural behavior. As results, it was obtained a good accuracy of the computacional models and the experimental tests in relation to the rupture load, in addition to the displacements values for the reinforced beams. However, the strain values achieved by the computacional model were higher than the experimental analysis rate values. Besides, it was also noticed that the beams had an increase of the stiffness with the addition of the reinforced layers. Furthermore, it was verified that the anchorage increments application caused an increase of the resistance, even more efficient than the addition of layers, for this case of study.
Heimisson, Gudmundur Torfi. "The importance of program-delivered differential reinforcement in the development of classical music auditory discrimination." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000440.
Повний текст джерелаKaruri, Stella. "Integration in Computer Experiments and Bayesian Analysis." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1187.
Повний текст джерелаOne modelling approach in dealing with deterministic output from computer experiments is to assume that the output is composed of a drift component and systematic errors, which are stationary Gaussian stochastic processes. A Bayesian approach is desirable as it takes into account all sources of model uncertainty. Apart from prior specification, one of the main challenges in a complete Bayesian model is integration. We take a Bayesian approach with a Jeffreys prior on the model parameters. To integrate over the posterior, we use two approximation techniques on the log scaled posterior of the correlation parameters. First we approximate the Jeffreys on the untransformed parameters, this enables us to specify a uniform prior on the transformed parameters. This makes Markov Chain Monte Carlo (MCMC) simulations run faster. For the second approach, we approximate the posterior with a Normal density.
A large part of the thesis is focused on the problem of integration. Integration is often a goal in computer experiments and as previously mentioned, necessary for inference in Bayesian analysis. Sampling strategies are more challenging in computer experiments particularly when dealing with computationally expensive functions. We focus on the problem of integration by using a sampling approach which we refer to as "GaSP integration". This approach assumes that the integrand over some domain is a Gaussian random variable. It follows that the integral itself is a Gaussian random variable and the Best Linear Unbiased Predictor (BLUP) can be used as an estimator of the integral. We show that the integration estimates from GaSP integration have lower absolute errors. We also develop the Adaptive Sub-region Sampling Integration Algorithm (ASSIA) to improve GaSP integration estimates. The algorithm recursively partitions the integration domain into sub-regions in which GaSP integration can be applied more effectively. As a result of the adaptive partitioning of the integration domain, the adaptive algorithm varies sampling to suit the variation of the integrand. This "strategic sampling" can be used to explore the structure of functions in computer experiments.
Rodriguez, George IV. "Finite Element Modeling of Delamination Damage in Carbon Fiber Laminates Subject to Low-Velocity Impact and Comparison with Experimental Impact Tests Using Nondestructive Vibrothermography Evaluation." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1583.
Повний текст джерелаPekar, Marek. "Modální analýza lopatek oběžného kola vírové turbíny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231288.
Повний текст джерелаSun, Fangfang. "On A-optimal Designs for Discrete Choice Experiments and Sensitivity Analysis for Computer Experiments." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345231162.
Повний текст джерелаDrozdzal, Michal. "Sequential image analysis for computer-aided wireless endoscopy." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/145614.
Повний текст джерелаNagy, Béla. "Valid estimation and prediction inference in analysis of a computer model." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1561.
Повний текст джерелаHardas, Manas Sudhakar. "SEGMENTATION AND INTEGRATION IN TEXT COMPREHENSION: A MODEL OF CONCEPT NETWORK GROWTH." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1334593269.
Повний текст джерелаTamrakar, Anjila. "SPICE: A Software Tool for Studying End-user’s Insecure Cyber Behavior and Personality-traits." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2236.
Повний текст джерелаGupta, Abhishek. "Robust design using sequential computer experiments." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/492.
Повний текст джерелаSánchez, Secades Juan María. "Multiple feature temporal models for the characterization of semantic video contents." Doctoral thesis, Universitat Autònoma de Barcelona, 2003. http://hdl.handle.net/10803/3036.
Повний текст джерелаLa semántica de nivel medio se encuentra implícita en las características de bajo nivel, dado que un concepto semántico concreto genera una combinación específica de valores de las mismas. El problema consiste en "tender un puente sobre el vacío" entre las características de bajo nivel que se observan y sus correspondientes conceptos semánticos de nivel medio ocultos. Para establecer relaciones entre estos dos niveles, se utilizan técnicas de visión por computador y procesamiento de imágenes. Otras disciplinas como la cinematografía y la semiótica también proporcionan pistas importantes para determinar como se usan las características de bajo nivel para crear conceptos semánticos. Una descripción adecuada de las características de bajo nivel puede proporcionar una representación de sus correspondientes contenidos semánticos. Más en concreto, el color resumido en un histograma se utiliza para representar la apariencia de los objetos. Cuando el objeto es el fondo de la escena, su color aporta información sobre la localización. De la misma manera, en esta tesis se analiza la semántica que transmite una descripción del movimiento. Las características de movimiento resumidas en una matriz de coocurrencias temporales proporcionan información sobre las operaciones de la cámara y el tipo de toma (primer plano, etc.) en función de la distancia relativa entre la cámara y los objetos filmados.
La principal contribución de esta tesis es una representación de los contenidos visuales del vídeo basada en el resumen del comportamiento dinámico de las características de bajo nivel como procesos temporales descritos por cadenas de Markov. Los estados de la cadena de Markov vienen dados por los valores observados de una característica de bajo nivel. A diferencia de las representaciones de los shots basadas en keyframes, el modelo de cadena de Markov considera información de todos los frames del shot en la misma representación. Las medidas de similitud naturales en un marco probabilístico, como la divergencia de Kullback-Leibler, pueden ser utilizadas para comparar cadenas de Markov y, por tanto, el contenido de los shots que representan. En la misma representación se pueden combinar múltiples características de las imágenes mediante el acoplamiento de sus correspondientes cadenas. Esta tesis presenta diferentes formas de acoplar cadenas de Markov, y en particular la llamada Cadenas Acopladas de Markov (Coupled Markov Chains, CMC). También se detalla un método para encontrar la estructura de acoplamiento óptima en términos de coste mínimo y mínima pérdida de información, ya que esta merma se relaciona directamente con la pérdida de precisión de la estructura acoplada para representar contenidos de vídeo. Durante el proceso de cálculo de las representaciones de los shots se detectan las fronteras entre éstos usando el mismo modelo y medidas de similitud.
Cuando las características de color y movimiento se combinan, la representación en cadenas acopladas de Markov proporciona un descriptor semántico de nivel medio que contiene información implícita sobre objetos (sus identidades, tamaños y patrones de movimiento), movimiento de cámara, localización, tipo de toma, relaciones temporales entre los elementos que componen la escena y actividad global, entendida como la cantidad de acción. Conceptos semánticos más complejos emergen de la unión de estos descriptores de nivel medio, tales como "cabeza parlante", que surge de la combinación de un primer plano con el color de la piel de la cara. Añadiendo el componente de localización en el dominio de Noticiarios, las cabezas parlantes se pueden subclasificar en "presentadores" (localizados en estudio) y "corresponsales" (localizados en exteriores). Estas y otras categorías semánticamente significativas aparecen cuando los shots representados usando el modelo CMC se agrupan de forma no supervisada. Los conceptos mejor definidos se corresponden con grupos compactos, que pueden ser detectados usando una medida de densidad. Conocimiento de alto nivel sobre el dominio se puede definir mediante simples reglas basadas en estos conceptos, que establecen fronteras en la estructura semántica del vídeo. El modelado de contenidos de vídeo por cadenas acopladas de Markov unifica los primeros pasos del proceso de análisis semántico de vídeo y proporciona una representación de nivel medio semánticamente significativa sin necesidad de detectar previamente las fronteras entre shots.
The high-level structure of a video can be obtained once we have knowledge about the domain plus a representation of the contents that provides semantic information. In this context, intermediate-level semantic representations are defined in terms of low-level features and the information they convey about the contents of the video. Intermediate-level representations allow us to obtain semantically meaningful clusterings of shots, which are then used together with high-level domain-specific knowledge in order to obtain the structure of the video. Intermediate-level representations are usually domain-dependent as well. The descriptors involved in the representation are specifically tailored for the application, taking into account the requirements of the domain and the knowledge we have about it. This thesis proposes an intermediate-level representation of video contents that allows us to obtain semantically meaningful clusterings of shots. This representation does not depend on the domain, but still provides enough information to obtain the high-level structure of the video by combining the contributions of different low-level image features to the intermediate-level semantics.
Intermediate-level semantics are implicitly supplied by low-level features, given that a specific semantic concept generates some particular combination of feature values. The problem is to bridge the gap between observed low-level features and their corresponding hidden intermediate-level semantic concepts. Computer vision and image processing techniques are used to establish relationships between them. Other disciplines such as filmmaking and semiotics also provide important clues to discover how low-level features are used to create semantic concepts. A proper descriptor of low-level features can provide a representation of their corresponding semantic contents. Particularly, color summarized as a histogram is used to represent the appearance of objects. When this object is the background, color provides information about location. In the same way, the semantics conveyed by a description of motion have been analyzed in this thesis. A summary of motion features as a temporal cooccurrence matrix provides information about camera operation and the type of shot in terms of relative distance of the camera to the subject matter.
The main contribution of this thesis is a representation of visual contents in video based on summarizing the dynamic behavior of low-level features as temporal processes described by Markov chains (MC). The states of the MC are given by the values of an observed low-level feature. Unlike keyframe-based representations of shots, information from all the frames is considered in the MC modeling. Natural similarity measures such as likelihood ratios and Kullback-Leibler divergence are used to compare MC's, and thus the contents of the shots they are representing. In this framework, multiple image features can be combined in the same representation by coupling their corresponding MC's. Different ways of coupling MC's are presented, particularly the one called Coupled Markov Chains (CMC). A method to find the optimal coupling structure in terms of minimal cost and minimal loss of information is detailed in this dissertation. The loss of information is directly related to the loss of accuracy of the coupled structure to represent video contents. During the same process of computing shot representations, the boundaries between shots are detected using the same modeling of contents and similarity measures.
When color and motion features are combined, the CMC representation provides an intermediate-level semantic descriptor that implicitly contains information about objects (their identities, sizes and motion patterns), camera operation, location, type of shot, temporal relationships between elements of the scene and global activity understood as the amount of action. More complex semantic concepts emerge from the combination of these intermediate-level descriptors, such as a "talking head" that combines a close-up with the skin color of a face. Adding the location component in the News domain, talking heads can be further classified into "anchors" (located in the studio) and "correspondents" (located outdoors). These and many other semantically meaningful categories are discovered when shots represented using the CMC model are clustered in an unsupervised way. Well-defined concepts are given by compact clusters, which can be determined by a measure of their density. High-level domain knowledge can then be defined by simple rules on these salient concepts, which will establish boundaries in the semantic structure of the video. The CMC modeling of video shots unifies the first steps of the video analysis process providing an intermediate-level semantically meaningful representation of contents without prior shot boundary detection.