911 resultados para Symbolic and Algebraic Manipulation


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This paper is a contribution to Mathematical fuzzy logic, in particular to the algebraic study of t-norm based fuzzy logics. In the general framework of propositional core and ?-core fuzzy logics we consider three properties of completeness with respect to any semantics of linearly ordered algebras. Useful algebraic characterizations of these completeness properties are obtained and their relations are studied. Moreover, we concentrate on five kinds of distinguished semantics for these logics-namely the class of algebras defined over the real unit interval, the rational unit interval, the hyperreals (all ultrapowers of the real unit interval), the strict hyperreals (only ultrapowers giving a proper extension of the real unit interval) and finite chains, respectively-and we survey the known completeness methods and results for prominent logics. We also obtain new interesting relations between the real, rational and (strict) hyperreal semantics, and good characterizations for the completeness with respect to the semantics of finite chains. Finally, all completeness properties and distinguished semantics are also considered for the first-order versions of the logics where a number of new results are proved. © 2009 Elsevier B.V. All rights reserved.

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We investigate the differences --- conceptually and algorithmically --- between affine and projective frameworks for the tasks of visual recognition and reconstruction from perspective views. It is shown that an affine invariant exists between any view and a fixed view chosen as a reference view. This implies that for tasks for which a reference view can be chosen, such as in alignment schemes for visual recognition, projective invariants are not really necessary. We then use the affine invariant to derive new algebraic connections between perspective views. It is shown that three perspective views of an object are connected by certain algebraic functions of image coordinates alone (no structure or camera geometry needs to be involved).

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The Kineticist's Workbench is a program that simulates chemical reaction mechanisms by predicting, generating, and interpreting numerical data. Prior to simulation, it analyzes a given mechanism to predict that mechanism's behavior; it then simulates the mechanism numerically; and afterward, it interprets and summarizes the data it has generated. In performing these tasks, the Workbench uses a variety of techniques: graph- theoretic algorithms (for analyzing mechanisms), traditional numerical simulation methods, and algorithms that examine simulation results and reinterpret them in qualitative terms. The Workbench thus serves as a prototype for a new class of scientific computational tools---tools that provide symbiotic collaborations between qualitative and quantitative methods.

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This article gives an overview of presuppositions and explanations posed by behaviorist psychology (particularly its radical branch), cognitive–nativist sciences (i.e. psycholinguistics and a branch of cognitive psychology) and other disciplines regarding important psychological events such as anxiety, stress, fear, mood states and language. In relation to the discussion of environment versus genetics, contributions from behavioral neurobiology and neuropsychology are added, showing evidence of traits that can be multigenerationally inherited in a non-genetic way, which have an impact thought the life of organisms and on their way of interacting with the environment; ways in which behavior can be altered by recently unsuspected environmental agents or events, and the overlooked role of prenatal experiences in the explanation of behavior. The evidence calls into question presuppositions made by the academic disciplines listed above, and suggests alternative behavior reinterpretations and explanations

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This paper investigates the impact of price consciousness, perceived risk, and ethical obligation on attitude and intention towards counterfeit products. Data were collected from a sample of 200 respondents via an online questionnaire. A conceptual model was derived and tested via structural equation modelling in the contexts of symbolic and experiential counterfeit products. Findings show differences in the factors (and weight thereof) impacting attitude and purchase intention in the two product contexts. Specifically, ethical obligation and perceived risk are found to be significant predictors of attitude towards both symbolic and counterfeit products, while price consciousness is found to predict only attitude towards experiential products, but not purchase intention in either counterfeit product context.

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The study explores the influence of the independent and interdependent self-construals on actual purchase behavior and the mediating role of consumer preferences for symbolic and hedonic meanings. Data were collected through a survey of about 1,000 respondents. Results indicate that independent consumers draw on the self/hedonic- and status-symbolic resources of clothing in the construction and expression of their identities. Regarding the interdependent consumers, they show no interest in clothing affiliation and status symbolism. The degree of preference for status-symbolic meaning mediates all effects of the independent and interdependent self-construals on actual purchase behavior; self-expressive/hedonic preferences mediate two of the three effects of the independent self on actual purchase behavior when accounting for suppression effects, whereas the expected mediation of preference for affiliation meaning is not supported.

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This study investigates the numerical simulation of three-dimensional time-dependent viscoelastic free surface flows using the Upper-Convected Maxwell (UCM) constitutive equation and an algebraic explicit model. This investigation was carried out to develop a simplified approach that can be applied to the extrudate swell problem. The relevant physics of this flow phenomenon is discussed in the paper and an algebraic model to predict the extrudate swell problem is presented. It is based on an explicit algebraic representation of the non-Newtonian extra-stress through a kinematic tensor formed with the scaled dyadic product of the velocity field. The elasticity of the fluid is governed by a single transport equation for a scalar quantity which has dimension of strain rate. Mass and momentum conservations, and the constitutive equation (UCM and algebraic model) were solved by a three-dimensional time-dependent finite difference method. The free surface of the fluid was modeled using a marker-and-cell approach. The algebraic model was validated by comparing the numerical predictions with analytic solutions for pipe flow. In comparison with the classical UCM model, one advantage of this approach is that computational workload is substantially reduced: the UCM model employs six differential equations while the algebraic model uses only one. The results showed stable flows with very large extrudate growths beyond those usually obtained with standard differential viscoelastic models. (C) 2010 Elsevier Ltd. All rights reserved.

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Changes in dietary macronutrient intake alter muscle and blood substrate availability and are important for regulating gene expression. However, few studies have examined the effects of diet manipulation on gene expression in human skeletal muscle. The aim of this study was to quantify the extent to which altering substrate availability impacts on subsequent mRNA abundance of a subset of carbohydrate (CHO)- and fat-related genes. Seven subjects consumed either a low- (LOW; 0.7 g/kg body mass CHO) or high- (HIGH; 10 g/kg body mass CHO) CHO diet for 48 h after performing an exhaustive exercise bout to deplete muscle glycogen stores. After intervention, resting muscle and blood samples were taken. Muscle was analyzed for the gene abundances of GLUT4, glycogenin, pyruvate dehydrogenase kinase-4 (PDK-4), fatty acid translocase (FAT/CD36), carnitine palmitoyltransferase I (CPT I), hormone-sensitive lipase (HSL), β-hydroxyacyl-CoA dehydrogenase (΄β-HAD), and uncoupling binding protein-3 (UCP3), and blood samples for glucose, insulin, and free fatty acid (FFA) concentrations. Glycogen-depleting exercise and HIGH-CHO resulted in a 300% increase in muscle glycogen content (P < 0.001) relative to the LOW-CHO condition. FFA concentrations were twofold higher after LOW- vs. HIGH-CHO (P < 0.05). The exercise-diet manipulation exerted a significant effect on transcription of all carbohydrate-related genes, with an increase in GLUT4 and glycogenin mRNA abundance and a reduction in PDK-4 transcription after HIGH-CHO (all P < 0.05). FAT/CD36 (P < 0.05) and UCP3 (P < 0.01) gene transcriptions were increased following LOW-CHO. We conclude that 1) there was a rapid capacity for a short-term exercise and diet intervention to exert coordinated changes in the mRNA transcription of metabolic related genes, and 2) genes involved in glucose regulation are increased following a high-carbohydrate diet.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)