3,072 research outputs found
The Guppy Effect as Interference
People use conjunctions and disjunctions of concepts in ways that violate the
rules of classical logic, such as the law of compositionality. Specifically,
they overextend conjunctions of concepts, a phenomenon referred to as the Guppy
Effect. We build on previous efforts to develop a quantum model that explains
the Guppy Effect in terms of interference. Using a well-studied data set with
16 exemplars that exhibit the Guppy Effect, we developed a 17-dimensional
complex Hilbert space H that models the data and demonstrates the relationship
between overextension and interference. We view the interference effect as, not
a logical fallacy on the conjunction, but a signal that out of the two
constituent concepts, a new concept has emerged.Comment: 10 page
Modeling Concept Combinations in a Quantum-theoretic Framework
We present modeling for conceptual combinations which uses the mathematical
formalism of quantum theory. Our model faithfully describes a large amount of
experimental data collected by different scholars on concept conjunctions and
disjunctions. Furthermore, our approach sheds a new light on long standing
drawbacks connected with vagueness, or fuzziness, of concepts, and puts forward
a completely novel possible solution to the 'combination problem' in concept
theory. Additionally, we introduce an explanation for the occurrence of quantum
structures in the mechanisms and dynamics of concepts and, more generally, in
cognitive and decision processes, according to which human thought is a well
structured superposition of a 'logical thought' and a 'conceptual thought', and
the latter usually prevails over the former, at variance with some widespread
beliefsComment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1311.605
Microgravity vibration isolation: An optimal control law for the one-dimensional case
Certain experiments contemplated for space platforms must be isolated from the accelerations of the platforms. An optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator (LQR) approach) along with constant feedforward (preview) gains. The quadratic cost function for this control algorithm effectively weights external accelerations of the platform disturbances by a factor proportional to (1/omega)(exp 4). Low frequency accelerations (less than 50 Hz) are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feedforward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and velocities and the absolute accelerations of the experiment and space platform are available
Control issues of microgravity vibration isolation
Active vibration isolation systems contemplated for microgravity space experiments may be designed to reach given performance requirements in a variety of ways. An analogy to passive isolation systems proves to be illustrative but lacks the flexibility as a design tool of a control systems approach and may lead to poor design. Control theory as applied to vibration isolation is reviewed and passive analogies discussed
Pruning Algorithms for Pretropisms of Newton Polytopes
Pretropisms are candidates for the leading exponents of Puiseux series that
represent solutions of polynomial systems. To find pretropisms, we propose an
exact gift wrapping algorithm to prune the tree of edges of a tuple of Newton
polytopes. We prefer exact arithmetic not only because of the exact input and
the degrees of the output, but because of the often unpredictable growth of the
coordinates in the face normals, even for polytopes in generic position. We
provide experimental results with our preliminary implementation in Sage that
compare favorably with the pruning method that relies only on cone
intersections.Comment: exact, gift wrapping, Newton polytope, pretropism, tree pruning,
accepted for presentation at Computer Algebra in Scientific Computing, CASC
201
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Effects of classification context on categorization in natural categories
The patterns of classification of borderline instances of eight common taxonomic categories were examined under three different instructional conditions to test two predictions: first, that lack of a specified context contributes to vagueness in categorization, and second, that altering the purpose of classification can lead to greater or lesser dependence on similarity in classification. The instructional conditions contrasted purely pragmatic with more technical/quasi-legal contexts as purposes for classification, and these were compared with a no-context control. The measures of category vagueness were between-subjects disagreement and within-subjects consistency, and the measures of similarity based categorization were category breadth and the correlation of instance categorization probability with mean rated typicality, independently measured in a neutral context. Contrary to predictions, none of the measures of vagueness, reliability, category breadth, or correlation with typicality were generally affected by the instructional setting as a function of pragmatic versus technical purposes. Only one subcondition, in which a situational context was implied in addition to a purposive context, produced a significant change in categorization. Further experiments demonstrated that the effect of context was not increased when participants talked their way through the task, and that a technical context did not elicit more all-or-none categorization than did a pragmatic context. These findings place an important boundary condition on the effects of instructional context on conceptual categorization
A "Kane's Dynamics" Model for the Active Rack Isolation System
In the late 1980s, microgravity researchers began to voice their concern that umbilical-transmitted energy could significantly degrade the acceleration environment of microgravity space science experiments onboard manned spacecraft. Since umbilicals are necessary for many experiments, control designers began to seek ways to compensate for these "indirect" disturbances. Hampton, et al., used the Kane s method to develop a model of the active rack isolation system (ARIS) that includes (1) actuator control forces, (2) direct disturbance forces, and (3) indirect, actuator-transmitted disturbances. Their model does not, however, include the indirect, umbilical-transmitted disturbances. Since the umbilical stiffnesses are not negligible, these indirect disturbances must be included in the model. Until the umbilicals have been appropriately included, the model will be incomplete. This Technical Memorandum presents a nonlinear model of ARIS with umbilicals included. Model verification was achieved by utilizing two commercial-off-the-shelf software tools. Various forces and moments were applied to the model to yield simulated responses of the system. Plots of the simulation results show how various critical points on an ARIS-outfitted international standard payload rack behave under the application of direct disturbances, indirect disturbances, and control forces. Simulations also show system response to a variety of initial conditions
Feature integration in natural language concepts
Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts
Normal versus abnormal structure: considerations in morphologic responses of teleosts to pollutants.
Consideration of newer more quantitative morphologic approaches to the study of aquatic pollutants can provide opportunity for collaborative/integrated studies with other subdisciplines in toxicology. Current commonly employed morphologic approaches result largely in subjective findings difficult to analyze statistically and often are directed at levels of structural organization inconsistent with biochemical and physiological approaches. We review some of the methods and approaches available for correlated structure/function studies and present examples from normal and altered skin, gill, and liver of teleosts
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