Conceptual bias

Example 3-8 The hypothesis space is often supposed to be constrained by a conceptual bias and a syntactic bias an acceptable hypothesis satisfies both biases. A hypothesis is characteristic for a set of examples iff it is satisfied by all the positive examples of A hypothesis is discriminant for iff its negation is satisfied by all the negative examples of . An acceptable hypothesis is admissible consistent) for iff it is characteristic for E and discriminant for The version space for a set of examples is the set of all admissible hypotheses (versions) for . 

The presence of properties (whose actual language is application-specific, and thus left unspecified in this part) is meant to overcome the problems of ambiguity and limited expressive power of specifications by examples, while still preserving the virtues of naturalness and conciseness of such specifications. The predicates used in the properties constitute a partial basis set, and thus a partial conceptual bias for synthesis. 

Every one of us working in the held has some bias or other. One of mine concerns the question of macromolecular sequences. The bias is, that the bottom-up approach to the origin of life will never be close to a solution - both conceptually and experimentally - unhl the problem of the onset of macromolecular sequences is clarihed. Obviously the origin of the specihc macromolecular sequences (as opposed to simple polymerizahon) is not an easy queshon to answer, as it is linked to the general problem of structure regulahon. 

We have reviewed current conceptual and modeling approaches in mixture eco-toxicology as well as current experimental evidence to derive practical risk assessment protocols for species and species assemblages. From the review of conceptual approaches in mixture ecotoxicology, it appears that there is a difference between a mechanistic view of joint action from a compound mixture and a probabilistic perspective on combined toxicity and mixture risk. A mechanistic view leads to emphasis on the distinction of modes of action and physicochemical properties first, then on the choice of the appropriate joint toxicity model, followed by a comparison of the models prediction with experimental observations. A probabilistic orientation leads to the observation that concentration addition often yields a relatively satisfactory quantitative prediction of observations for the integral level of effects as observed in individual organisms or populations. In these applications, concentration addition is frequently connected with a slight bias to conservatism, especially for compounds with different modes of action (Backhaus et al. 2000,2004 Faust et al. 2003). 

This part provides a conceptual understanding of stochastic, bias, and fitting errors m frequency-domain measurements. A major advantage of frequency-domain measurements is that real and imaginary parts of the response must be internally consistent. The expression of this consistency takes different forms that are known collectively as the Kramers-Kronig relations. The Kramers-Kronig relations and their application to spectroscopy measurements are described. Measurement models, used to assess the error structure, are described and compared with process models used to extract physical properties. 

The appropriateness of each LoE and the criteria used to establish a linkage approach should be considered in the problem formulation and the conceptual model development. In this manner, the rules for accepting a potential stressor as a cause can be set before the analysis begins. It is critical that these rules be established and not altered unless there is compelling evidence to do so. This process prevents a post-hoc WoE approach and the introduction of investigator bias. 

Klee G. A conceptual model for establishing tolerance limits for analytical bias and imprecision based on variations in population test distributions. Clin Chim Acta 1997 260 175-88. 

Akaike s criterion and its derivations has been called by some [see Verbeke and Molenberghs (2000) for example] as a minimization function plus a penalty term for the number of parameters being estimated. As more model parameters are added to a model, 2LL tends to decrease but 2 p increases. Hence, AIC may decrease to a point as more parameters are added to a model but eventually the penalty term dominates the equation and AIC begins to increase. Conceptually this fits into the concept of bias-variance trade-off or the trade-off between overfitting and underfitting. 

The paper is not meant to be a scholarly review of DFT, but rather an informal guide to its conceptual basis and some recent developments and advances. The Hohenberg-Kohn theorem and the Kohn-Sham equations are discussed in some detail. Approximate density functionals, selected aspects of applications of DFT, and a variety of extensions of standard DFT are also discussed, albeit in less detail. Throughout it is attempted to provide a balanced treatment of aspects that are relevant for chemistry and aspects relevant for physics, but with a strong bias towards conceptual foundations. The text is intended to be read before (or in parallel with) one of the many excellent more technical reviews available in the literature. The author apologizes to all researchers whose work has not received proper consideration. The limits of the author s knowledge, as well as the limits of the available space and the nature of the intended audience, have from the outset prohibited any attempt at comprehensiveness.1... 

Another important role of an electronic structure theory is to provide a conceptual framework in which to think and organize [1,2]. In this role theoretical predictions need not be quantitative but should provide a bias toward correct thinking about further experimental and theoretical studies. When combined with the ideas of symmetry and overlap, the concepts of perturbation, orbital interaction, orbital mixing and orbital occupation have been indispensable not only in understanding structure-property... 

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