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PubMed1985

A program for machine learning of counting criteria: empirical induction of logic-based classification rules.

A program has been developed which derives classification rules from empirical observations and expresses these rules in a knowledge representation format called 'counting criteria'. Decision rules derived in this format are often more comprehensible than rules derived by existing machine learning programs such as AQ11. Use of the program is illustrated by the inference of discrimination criteria for certain types of bacteria based upon their biochemical characteristics. The program may be useful for the conceptual analysis of data and for the automatic generation of prototype knowledge bases for expert systems.

Artificial Intelligence↗
PubMed1986

Creativity in illness: methodological linkages to the logic and language of science in folk pursuit of health in central Italy.

Field research in a rural section of central Italy provides the basis for this paper on the structuring of information about health and illness. Here a population is presently engaged in creating a grammar and rhetoric of health culture and life style that begins to link its own traditions to what it learns of medical scientific method, both in praxis and from media fare on the 'discourse' of medical science. We follow this thought modality in exploration of therapeutic choices and the evolving of ethnotherapies.

Attitude to Health↗
PubMed1988

Autopoiesis: the status of its system logic.

The concept of autopoiesis, amended as a system theory, is necessary and sufficient to provide an operational definition of life, a set of criteria by which the living are categorically distinguished from the non-living. Limitations are placed on the domains in which autopoiesis may be exhibited.

Biology↗
PubMed2005

Information leakage from logically equivalent frames.

Framing effects are said to occur when equivalent frames lead to different choices. However, the equivalence in question has been incompletely conceptualized. In a new normative analysis of framing effects, we complete the conceptualization by introducing the notion of information equivalence. Information equivalence obtains when no choice-relevant inferences can be drawn from the speaker's choice of frame. We show that, to support the normative implications traditionally attributed to framing effects, frames must be equivalent in this sense. We also present new evidence for McKenzie and Nelson's (2003) reference point hypothesis, which posits a tendency to cast descriptions in terms of what has increased relative to the reference point. This leakage of information about relative state violates information equivalence, and gives rise to a normative account of the most robust finding in the attribute framing literature - the valence-consistency of preference shifts. We argue that, more generally, valenced descriptions leak information about perceived valence. Such "implicit recommendations" may generalize the reference point explanation of the valence-consistent shift. Normative and psychological implications of the information leakage framework are discussed.

Choice Behavior↗
PubMed2006

Is this a dax which I see before me? Use of the logical argument disjunctive syllogism supports word-learning in children and adults.

Many authors have argued that word-learning constraints help guide a word-learner's hypotheses as to the meaning of a newly heard word. One such class of constraints derives from the observation that word-learners of all ages prefer to map novel labels to novel objects in situations of referential ambiguity. In this paper I use eye-tracking to document the mental computations that support this word-learning strategy. Adults and preschoolers saw images of known and novel objects, and were asked to find the referent of known and novel labels. Experiment 1 shows that adults systematically reject a known distractor (e.g. brush) before mapping a novel label (e.g. "dax") to a novel object. This is consistent with the proposal that participants worked through a Disjunctive Syllogism (i.e. Process-of-Elimination) to motivate the mapping of the novel label to the novel object. Experiment 2 shows that processing is similar for adults performing an implicit Disjunctive Syllogism (e.g. "the winner is the dax") and an explicit Disjunctive Syllogism (e.g. "the winner is not the iron"). Experiment 3 reveals that similar processes govern preschoolers' mapping of novel labels. Taken together, these results suggest that word-learners use Disjunctive Syllogism to motivate the mapping of novel labels to novel objects.

Adolescent↗
PubMed2004

Perception of disability in a public health perspective: a model based on fuzzy logic.

Measures of functional levels, commonly used to assess the safety and quality of life of individuals and populations, have not yet been derived from a fuzzy framework. The aim of this study is to estimate the degree of disability associated with varying functional levels, through a model based on fuzzy sets theory. A fuzzy linguistic model was developed to measure varying levels of functional disability, in accordance with the definitions of an individual's social and physical activities and mobility. One year of an adult's life whose mobility, social and physical activities were somewhat limited, was judged to be equivalent to 0.575 years free of functional disability. Results obtained from the fuzzy model approach those obtained with the quality of well-being scale (QWB), used as a conceptual framework. Such findings are encouraging, since the QWB is considered a consistent and valid approach for disability assessment and quality-of-life evaluation.

Adolescent↗
PubMed2004

The logic of reprobation: assessment and action rules for indirect reciprocation.

Ever since image-based models for indirect reciprocity were introduced, the relative merits of scoring vs. standing have been discussed to find out how important it is to differentiate between justified and non-justified defections. This is analogous to the question whether punishment can sustain cooperation even when it is costly. We show that an answer to this question can depend on details of the model, for instance concerning the probability distribution of the number of interactions experienced per player. We use extensive individual-based simulations to compare scoring, standing and other forms of assessing defections, and show that several forms of indirect reciprocation can robustly sustain cooperation. By most standards, standing is better than scoring, but nevertheless scoring is able to sustain cooperation in the presence of errors. The model presented here is based on three specifications: each player has a personal list of images of all co-players, a specific way of judging an observed situation, and a specific strategy to decide whether to cooperate or not.

Biological Evolution↗
PubMed2004

Automated human frontal lobe identification in MR images based on fuzzy-logic encoded expert anatomic knowledge.

Identification of human brain structures in MR images comprises an area of increasing interest, which also presents numerous methodological challenges. Here we describe a new knowledge-based automated method designed to identify several major brain sulci and then to define the frontal lobes by using the identified sulci as landmarks. To identify brain sulci, sulcal images were generated by morphologic operations and then separated into different components based on connectivity analysis. Subsequently, the individual anatomic features were evaluated by using fuzzy membership functions. The crisp decisions, i.e., the identification of sulci, were made by taking the maximum of the summation of all the membership functions. The identification was designed in a hierarchical order. The longitudinal fissure was extracted first. The left and right central sulci were then identified based on the left and right hemispheres. Next, the lateral sulci were identified based on the central sulci and hemispheres. Finally, the left and right frontal lobes were defined from the two hemispheres. The method was evaluated by visual inspection, comparison with manual segmentation, and comparison with manually volumetric results in references. The average Jaccard similarities of left and right frontal lobes between the automated and manual segmentation were 0.89 and 0.91, respectively. The average Kappa indices of left and right frontal lobes between the automated and manual segmentation were 0.94 and 0.95, respectively. These results show relatively high accuracy of using this novel method for human frontal lobe identification and segmentation.

Algorithms↗
PubMed2006

The causal psycho-logic of choice.

Choices do not merely identify one option among a set of possibilities; choosing is an intervention, an action that changes the world. As a result, good decision making generally requires a model specifying how actions are causally related to outcomes. Interventions license different inferences than observations because an event whose state has been determined by intervention is not diagnostic of the normal causes of that event. We integrate these ideas into a causal framework for decision making based on causal Bayes nets theory, and suggest that deliberate decision making is based on simplified causal models and imaginary interventions. The framework is consistent with what we know so far about how people make decisions.

Bayes Theorem↗
PubMed1998

Fuzzy logic and inflammatory protein variations.

This tutorial style paper has been written for physicians and biologists who are not necessarily familiar with fuzzy set theory and biomedical applications. The field is introduced in the framework of medical diagnosis problems and illustrated with an application to inflammatory protein variations. The model is of special interest in the processing of borderline cases, allowing a graded assignment of diagnoses to patients. Relationships between signs and diagnoses are interpreted as labels of fuzzy sets and it is shown how diagnoses can be derived from soft matching processes. In cases of poor diagnostic classification, appropriate weights are introduced, acting on characterizations of signs, in order to decrease their relative influence. As a consequence, when pattern matching is achieved, the final ranking of inflammatory syndromes assigned to a given patient might change to better fit the actual classification.

Acute-Phase Proteins↗
PubMed1999

Clinical and laboratory logic.

After elucidating the controversy that accompanied the birth of laboratory medicine, the Authors define and examine the concepts underlying clinical methodology. The mental operations of the clinician are analyzed, a distinction being made between the processes of: a) "categorization" of the patient's disease, and b) "explanation" for pathologic phenomena. The diagnostic procedure is usually based above all on categorization. In the first phase of this procedure the clinician searches for data that are of the greatest possible "informative value", and then goes works out a certain number of "syndromic complexes". In the second phase, on the basis of these "groups of signs", the physician must formulate a certain number of diagnostic hypotheses and evaluate the probability of the presence of a particular disease, in view of the presence of particular signs. Finally, two fundamental arguments of clinician are dealt with: "the confirmatory argument" and "the falsifying argument", and the value of these two inferences in conferring certainty or a certain grade of reliability on clinical judgement is analyzed and discussed.

Bayes Theorem↗
PubMed2003

Where's the logic in neurologic education?

Current practices in neurologic education, and medical education in general, are based largely on intuition and tradition rather than empiric evidence. Educational practices can and should be rigorously evaluated. The topics to be investigated fall into one or more of three broad categories: What should we teach? How should we teach it? How do we know what they have learned? This paper presents examples of research in each of these categories.

Education, Medical↗
PubMed2003

New approach based on fuzzy logic and principal component analysis for the classification of two-dimensional maps in health and disease. Application to lymphomas.

Two-dimensional (2D) electrophoresis is the most wide spread technique for the separation of proteins in biological systems. This technique produces 2D maps of high complexity, which creates difficulties in the comparison of different samples. The method proposed in this paper for the comparison of different 2D maps can be summarised in four steps: (a) digitalisation of the image; (b) fuzzyfication of the digitalised map in order to consider the variability of the two-dimensional electrophoretic separation; (c) decoding by principal component analysis of the previously obtained fuzzy maps, in order to reduce the system dimensionality; (d) classification analysis (linear discriminant analysis), in order to separate the samples contained in the dataset according to the classes present in said dataset. This method was applied to a dataset constituted by eight samples: four belonging to healthy human lymph-nodes and four deriving from non-Hodgkin lymphomas. The amount of fuzzyfication of the original map is governed by the sigma parameter. The larger the value, the more fuzzy theresulting transformed map. The effect of the fuzzyfication parameter was investigated, the optimal results being obtained for sigma = 1.75 and 2.25. Principal component analysis and linear discriminant analysis allowed the separation of the two classes of samples without any misclassification.

Electrophoresis, Gel, Two-Dimensional↗