Tversky

Asymmetry in a similarity measure is the result of asymmetrical weighing of a dissimilarity component - multiplication is commutative by definition, difference is not. By weighing a and h, one obtains asymmetric similarity measures, including the Tversky similarity measure c j aa 4- fih + c), where a and fi are user-defined constants. The Tversky measure can be regarded as a generalization of the Tanimoto and Dice similarity measures like them, it does not consider the absence matches d. A particular case is c(a + c), which measures the number of common features relative to all the features present in A, and gives zero weight to h. 

A generalisation of the similarity formulae for binary data can be derived, based on the work of Tversky [Tversky 1977 Bradshaw 1997]. This takes the form ... 

Bradshaw J 1997. Introduction to Tversky Similarity Measure. At http //www.daylight.com meetings / mu g97 / Bradshaw / MUG97 / tv tversky.html. 

The pragmatic beauty of the chemical fingerprint is that the more common features of two molecules that there are, the more common bits are set. The mathematic approach used to translate the fingerprint comparison data into a measure of similarity tunes the molecular comparison [5]. The Tanimoto similarity index works well when a relatively sparse fingerprint is used and when the molecules to be compared are broadly comparable in size and complexity [5]. If the nature of the molecules or the comparison desired is not adequately met by the Tanimoto index, multiple other indices are available to the researcher. For example, the Daylight software offers the user over ten similarity metrics, and the Pipeline Pilot as distributed offers at least three. Some of these metrics (e.g., Tversky, Cosine) offer better behavior if the query molecule is significantly smaller than the molecule compared to it. 

Consumers accept technology for medicinal purposes, but not necessarily for foods. These different attitudes toward medicine and food can be explained by the way the situation is framed—or perceived—by consumers. As Kahneman and Tversky (1986) have shown, people show a risk-taking tendency when the outcome is seen as the reduction of a loss ( I do not want to be sick ), but show a risk-aversive tendency when the outcome is identified as a gain ( I want to be healthy ). 

Tait, J. 1988. Public perceptions of biotechnology hazards. J. Chem. Technol. Biotechnol. 43, 363-372. Tversky, A. and Kahneman, D. 1981. The framing of decisions and the rationality of choice. Science 211, 453 158. 

Tuz Golu (lake), 5 784 Tversky similarity, 6 8 T vessicant agent, 5 816 physical properties, 5 817t Twaron fiber, 13 373 Tween surfactants, 24 150 12-membered ring macrolides, 15 272, 275t 2,6-TDI, reaction with a polyether triol, 25 459. See also Toluene diisocyanate (TDI)... 

A similarity index called subsimilaritywhich is short for substructure similarity, has been developed by developed by Hagadone (37). In form it is identical to one of the family of asymmetric similarity indices developed by Tversky (6) that is discussed in Subheading 2.2.2.,... 

Most similarity measures for binary-valued feature vectors in use today are symmetric Tversky (6), however, has defined an infinite family of asymmetric measures... 

The extreme forms, but not the intermediate forms, of asymmetric similarity defined by Tversky (6) given in Eqs. 2.26 and 2.27 can be transformed into two symmetric measures by taking the maximum and minimum of the set cardinalities in the denominators of the two equations. The forms of these equations are obtained in analogy to those developed by Petke (33) for vectors and field-based functions (see Subheadings 2.3. and 2.4. for further details) ... 

Fig. 4. (A) The other asymmetric Tversky similarity index, S VC, has a value of 0.69. Exchanging the roles of the query and target molecules (Q<=>T) gives (B), which shows that smaller target molecules are more likely to be retrieved from a large query structure using the asymmetric Tversky similarity index than the Tanimoto similarity index.

Shafir, Eldar, 1. Simonson, and Amos Tversky. 1993. "Reason-Based Choice." Cognition 49 11-36. 

However, as economics examines individual human behaviours more closely, it discovers examples of apparent irrationality that are not accounted for by existing theory. This is true even of purely monetary transactions. For instance, people value sunk costs more than the equivalent opportunity costs, and in experimental gambling situations frequently do not maximize expected value (Thaler 1980 Tversky and Kahneman 1981). In the real world, of course, any gambling reduces one s expected income, and yet gambling is a popular activity. 

Fredrik Barth Amartya Sen Arthur Stinchcombe Amos Tversky Bernard Williams... 

Amos Tversky is Professor of Psychology at Stanford University... 

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