首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
In [W. Burr, Functional interpretation of Aczel's constructive set theory, Annals of Pure and Applied Logic 104 (2000) 31–73] Wolfgang Burr presents a functional interpretation of constructive set theory in all finite types, , in a theory of constructive set functionals. is a subtheory of , containing bounded quantifiers only. His interpretation theorem reduces the consistency problem of (and certain extensions thereof) to the consistency problem of .We want to study admissible rules in , i.e. rules under which is closed. To do so, we study a Troelstra-style q-hybrid of, in fact, a modification × of Burr's translation. We introduce this modification in order to close a minor gap in Burr's proof of the functional interpretation of the schema of (Strong Collection).First of all, but surely after a short introduction, we analyse the less complex translation of modified realisation mr and its hybrids mq and mrt.  相似文献   

2.
In standard treatments of probability, is defined as the ratio of to , provided that . This account of conditional probability suggests a psychological question, namely, whether estimates of arise in the mind via implicit calculation of . We tested this hypothesis (Experiment 1) by presenting brief visual scenes composed of forms, and collecting estimates of relevant probabilities. Direct estimates of conditional probability were not well predicted by . Direct estimates were also closer to the objective probabilities defined by the stimuli, compared to estimates computed from the foregoing ratio. The hypothesis that arises from the ratio fared better (Experiment 2). In a third experiment, the same hypotheses were evaluated in the context of subjective estimates of the chance of future events.  相似文献   

3.
This study investigated age-related differences in working memory and inhibitory control (WMIC) in -, 4-, and -year-olds and how these differences were associated with differences in regulatory aspects of temperament, language comprehension, and brain electrical activity. A series of cognitive control tasks was administered to measure WMIC ability, including the Stroop-like day–night and the yes–no tasks. Baseline and task electroencephalographic data were collected. The Children's Behavior Questionnaire was used to assess caregiver perceptions of temperament with a particular interest in the effortful control and surgency factors, and language comprehension was measured with the Peabody-Picture Vocabulary Test-III. The results of this study demonstrated differential temperament-cognition relations for the three age groups, as positive associations were found between WMIC and effortful control for the - and 4-year-olds and negative associations were found between WMIC and surgency for the -year-olds. An increasingly robust relation between WMIC and language comprehension was demonstrated across the three age groups, as well as differential patterns of task-related brain electrical activity.  相似文献   

4.
A discrimination probability function obtained in the “same-different” paradigm assigns to every ordered pair of stimuli the probability with which they are judged to be different. This function is said to possess the regular minimality property if, for any stimulus pair ,
  相似文献   

5.
6.
7.
Fin swimming performance can be divided into underwater and surface water races. World records are about 10% faster for underwater swimming vs. surface swimming, but little is known about the advantage of underwater swimming for monofin swimming. Some authors reported that the air–water interface influences the kinematics and leads to a narrow vertical amplitude of the fin. On the one hand, surface swimming is expected to affect drag parameters (cross-sectional area (S) and active drag (AD)) when compared to underwater swimming. On the other hand, the surface swimming technique may also affect efficiency (ηF). The aim of this study is therefore to evaluate and compare drag parameters and efficiency during underwater and surface swimming. To this end, 12 international level monofin swimmers were measured during both underwater and surface swimming. Kinematic parameters (both dimensional and non-dimensional), ηF (calculated according to the Elongated-Body Theory), and AD (computed with Velocity Perturbation Method) were calculated for an underwater and a surface fin swimming trial, performed at maximal speed. As expected, results showed significantly lower velocities during surface swimming vs. underwater  = 2.5 m s−1 vs.  = 2.36 m s−1, p < .01). Velocities during underwater and surface swimming were strongly correlated (r = .97, p < .01). Underwater swimming was also associated with higher vertical amplitudes of the fin compared to surface swimming ( = 0.55 m vs. ) = 0.46 m, p < .01). Length-specific amplitudes (Aunder/Lb) were in the order of 20% during underwater swimming as for undulating fish, and significantly higher than during surface swimming (Asurf/Lb = 17%, p < .01). Efficiency for surface swimming was about 6% lower than for underwater swimming ( = 0.79 vs.  = 0.74, p < .01). This decrease could be associated with an increase in swimming frequency for surface swimming ( = 2.15 Hz vs.  = 2.08 Hz, p < .01). Active drag during surface swimming was about 7% higher than for underwater swimming ( = 78.9 N vs.  = 84.7 N, p < .01). A significantly smaller cross-sectional area for surface swimming ( = 0.053 m2 vs.  = 0.044 m2, p < .01) and higher drag coefficient for surface swimming ( = 0.47 vs.  = 0.69, p < .01) were measured. Finally, correlation between cross-sectional area and vertical amplitude of the fin was reported for both underwater and surface swimming. These results suggest that the performance improvement during underwater swimming is not only linked to a wave drag reduction effect but also to a specific swimming technique due to the free surface.  相似文献   

8.
Threshold autoregressive models can be used to study processes that are characterized by recurrent switches between two or more regimes, where switching is triggered by a manifest threshold variable. In this paper the performance of diverse information criteria for selecting the number of regimes in small to moderate sample sizes (i.e., n=50,100,200) is investigated. In addition it is investigated whether these information criteria can be used to determine whether the residual variances are identical across the regimes. It is concluded that for small sample sizes should be preferred, while for larger sample sizes either BIC or should be considered: The latter is the only information criterion that includes a penalty for the unknown threshold parameters.  相似文献   

9.
This paper continues the development of the Dissimilarity Cumulation theory and its main psychological application, Universal Fechnerian Scaling [Dzhafarov, E.N and Colonius, H. (2007). Dissimilarity Cumulation theory and subjective metrics. Journal of Mathematical Psychology, 51, 290-304]. In arc-connected spaces the notion of a chain length (the sum of the dissimilarities between the chain’s successive elements) can be used to define the notion of a path length, as the limit inferior of the lengths of chains converging to the path in some well-defined sense. The class of converging chains is broader than that of converging inscribed chains. Most of the fundamental results of the metric-based path length theory (additivity, lower semicontinuity, etc.) turn out to hold in the general dissimilarity-based path length theory. This shows that the triangle inequality and symmetry are not essential for these results, provided one goes beyond the traditional scheme of approximating paths by inscribed chains. We introduce the notion of a space with intermediate points which generalizes (and specializes to when the dissimilarity is a metric) the notion of a convex space in the sense of Menger. A space is with intermediate points if for any distinct there is a different point such that (where D is dissimilarity). In such spaces the metric G induced by D is intrinsic: coincides with the infimum of lengths of all arcs connecting to In Universal Fechnerian Scaling D stands for either of the two canonical psychometric increments and (ψ denoting discrimination probability). The choice between the two makes no difference for the notions of arc-connectedness, convergence of chains and paths, intermediate points, and other notions of the Dissimilarity Cumulation theory.  相似文献   

10.
A general Thurstonian-type representation (with stochastically interdependent images and probabilistic decisions) for a “same-different” discrimination probability function is a model in which the two stimuli are mapped into two generally interdependent random images and taking on their values in some “perceptual” space; and the realizations of these two random images in a given trial determine the probability with which and in this trial are judged to be different. While stochastically interdependent, and are selectively attributed to (influenced by), respectively, and , which is understood as the possibility of conditioning and on some random variable R that renders them stochastically independent, with their conditional distributions selectively depending on, respectively, and . A general Thurstonian-type representation is considered “well-behaved” if the conditional probability with which and , given a value of the conditioning random variable R, fall within two given subsets of the perceptual space, possess appropriately defined bounded directional derivatives with respect to and . It is shown that no such well-behaved Thurstonian-type representation can account for possessing two basic properties: regular minimality and nonconstant self-similarity. At the same time, an alternative to Thurstonian-type modeling (a model employing “uncertainty blobs” in stimulus spaces instead of random variables in perceptual spaces) is readily available that predicts these two properties “automatically”.  相似文献   

11.
The four personality type combinations derived from high and low extraversion () and high and low neuroticism () have been related to response patterns composed of three symptoms (affective disturbances, thinking disturbances, and blackouts) scored as present (+) or absent (−) after a single oral dose of the hallucinogenic drug LSD-25. Hypotheses for expected response patterns for each personality group were derived from a data set obtained by Kohnen and Lienert (1987). Significance of associations was tested by two strategies of polyprediction configural frequency analysis (CFA): multiple uniprediction and biprediction CFA. Both strategies yielded a significant hyperpresentation of all three symptoms present in E+N+ (hysterics), merely thinking disorders in dysthymics (E−N+), merely affective symptoms in E+N− (stable extraverts), and merely blackouts in N−E− (stable introverts). Authors tried to relate these symptoms to Kretschmer's temperament types and could afterwards show by a chessboard modification of prediction CFA, that by applying two combined hypotheses for two personality types each, the significance of the predicted associations could be increased.  相似文献   

12.
Deduction chains represent a syntactic and in a certain sense constructive method for proving completeness of a formal system. Given a formula , the deduction chains of are built up by systematically decomposing into its subformulae. In the case where is a valid formula, the decomposition yields a (usually cut-free) proof of . If is not valid, the decomposition produces a countermodel for . In the current paper, we extend this technique to a semiformal system for the Logic of Common Knowledge. The presence of fixed point constructs in this logic leads to potentially infinite-length deduction chains of a non-valid formula, in which case fairness of decomposition requires special attention. An adequate order of decomposition also plays an important role in the reconstruction of the proof of a valid formula from the set of its deduction chains.  相似文献   

13.
The temporal context model (TCM) has been extensively applied to recall phenomena from episodic memory. Here we use the same formulation of temporal context to construct a sequential learning model called the predictive temporal context model (pTCM) to extract the generating function of a language from sequentially-presented words. In pTCM, temporal context is used to generate a prediction vector at each step of learning and these prediction vectors are in turn used to construct semantic representations of words on the fly. The semantic representation of a word is defined as the superposition of prediction vectors that occur prior to the presentation of the word in the sequence. Here we create a formal framework for pTCM and prove several useful results. We explore the effect of manipulating the parameters of the model on learning a sequence of words generated by a bi-gram generating function. In this simple case, we demonstrate that feeding back the constructed semantic representation into the temporal context during learning improves the performance of the model when trained with a finite training sequence from a language with equivalence classes among some words. We also describe , a variant of the model that is identical to pTCM at steady state. has significant computational advantages over pTCM and can improve the quality of its prediction for some training sequences.  相似文献   

14.
Generalized Pexider equation on a restricted domain   总被引:1,自引:0,他引:1  
Let X be a normed space and D be a nonempty, open and connected subset of X×X. Inspired by a problem of J. Aczél, we study the functional equation
  相似文献   

15.
This study investigated the roles of problem structure and strategy use in problem encoding. Fourth-grade students solved and explained a set of typical addition problems (e.g., ) and mathematical equivalence problems (e.g., or ). Next, they completed an encoding task in which they reconstructed addition and equivalence problems after viewing each for 5 s. Equivalence problems of the form overlap with a perceptual pattern found in traditional arithmetic problems (i.e., answer blank in final position), and students’ encoding was poorest on problems of this type. Individual differences in encoding the equivalence problems were related to variations in strategy use. Some students solved blank-final equivalence problems using the standard arithmetic strategy of performing all given operations on all given numbers. These students made more errors in encoding problem structure, but fewer errors in encoding the numbers, than did students who solved the problems using correct or other incorrect strategies. Moreover, students who expressed many strategies for solving the blank-final equivalence problems made fewer errors in encoding problem structure, but more errors in encoding the numbers, than did students who expressed only a single strategy. Results highlight that encoding is intended to guide action and that prior experience can simultaneously facilitate and interfere with accurate encoding.  相似文献   

16.
17.
Samoan youths are critically under-studied in research on youth violence prevention and adolescent development. When Samoan adolescents are included in research investigations, they are typically obscured into the much larger aggregated categories of “Pacific Islanders” or “Asian Americans and Pacific Islanders.” The present study is one of the first to examine Samoans exclusively and compare the differences between Samoan youths residing in American Samoa and those residing in Hawaii. In an effort to gauge the acculturative processes of adolescents in American Samoan and Hawaii, the present study compared these two groups' self-reports of violence, substance use, grade-point average, scholastic aspirations, importance of religion, ethnic identity, parenting discipline style, and family support. Overall, the results indicated higher rates among Samoan adolescents in Hawaii as compared to those in American Samoa on one violence item and on substance use indicators (i.e., alcohol and marijuana). Samoan adolescents in American Samoa also reported higher levels of protective factors related to the importance of religion (especially for girls), ethnic identity, and family support. However, Samoan adolescents in Hawaii had higher scholastic aspirations than those in American Samoa, despite having lower grade-point averages. In general, Samoan students who did not self-report engaging in violence had higher rates of protective factors as compared to those who indicated engaging in violence. Statistically significant interactions reflected more complex effects. The implications of these findings in conjunction with the results of the Youth Risk Behavior Survey (YRBS) are discussed in the context of Samoan culture, acculturation, and youth development.  相似文献   

18.
-Cycloserine (DCS), a partial agonist of the glycine recognition site of the N-methyl -aspartate receptor, has beneficial effects on learning and memory. In order to investigate its potential to influence learning and memory of both the response and the stimulus attributes of training, male Sprague-Dawley albino rats were trained in a one-trial inhibitory avoidance task following an acute intraperitoneal injection of DCS (3 mg/kg) or an equal volume of saline. In order to measure memory for stimulus attributes, testing involved a context shift paradigm, in which subjects are tested in either the environment of training or a different one. Good memory for the contextual attributes of training is indicated by poor performance in the alternate context. Retention was assessed either 1, 7, or 14 days after training. At 1 day, Saline subjects were affected by a change in context, while DCS subjects were not. In subjects tested 1 week following training, Saline subjects were no longer affected by a change in context, in that they performed the avoidance response in both contexts. This indicates the forgetting of stimulus attributes in Saline subjects. DCS subjects did show the context shift effect at 1 week, indicating the retention of stimulus attributes. Finally, Saline subjects demonstrated the context shift rebound at 14 days, while DCS subjects performed equivalently in both contexts. Taken together, these data suggest that DCS may enhance retention of fear and slow the forgetting of stimulus attributes.  相似文献   

19.
We present a new mathematical notion, dissimilarity function, and based on it, a radical extension of Fechnerian Scaling, a theory dealing with the computation of subjective distances from pairwise discrimination probabilities. The new theory is applicable to all possible stimulus spaces subject to the following two assumptions: (A) that discrimination probabilities satisfy the Regular Minimality law and (B) that the canonical psychometric increments of the first and second kind are dissimilarity functions. A dissimilarity function Dab for pairs of stimuli in a canonical representation is defined by the following properties: (1) ab?Dab>0; (2) Daa=0; (3) If and , then ; and (4) for any sequence {anXnbn}nN, where Xn is a chain of stimuli, DanXnbn→0?Danbn→0. The expression DaXb refers to the dissimilarity value cumulated along successive links of the chain aXb. The subjective (Fechnerian) distance between a and b is defined as the infimum of DaXb+DbYa across all possible chains X and Y inserted between a and b.  相似文献   

20.
This study employed conservation of resources (CORs) theory to propose and test relationships between resources possessed by employees, their coping strategies, and emotional exhaustion. The participants consisted of 600 full-time government employees. An OLS regression showed that, in general and consistent with COR theory, resource levels were positively associated with the use of active coping strategies (i.e., positive orientation, working harder, and seeking advice and assistance) and negatively associated with avoidance. With the exception of task complexity, resources were associated with lower levels of emotional exhaustion. Although a positive orientation was negatively associated with emotional exhaustion, another active coping strategy, namely, working harder, was positively associated with emotional exhaustion. We discuss the several complexities predicted and found, and how COR may be used elaborate the exhaustion model.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号