Interactive Selective and Adaptive Clustering for Detection of Microcalcifications in Mammograms

Estevez, L., Kehtarnavaz, N., and Wendt, R. III, Interactive Selective and Adaptive Clustering for Detection of Microcalcifications in Mammograms,Digital Signal Processing6(1996), 224–232.This paper presents a clustering algorithm, called interactive selective and adaptive clustering (Isaac), to assist radiologists in looking for small clusters of microcalcifications in mammograms. Isaac is developed to identify suspicious microcalcification regions which are missed by other classification techniques due to false positive samples in the feature space. It comprises two parts: (i) selective clustering and (ii) interactive adaptation. The first part reduces the number of false positives by identifying the microcalcification subspace or domains in the feature space. The second part allows the radiologist to improve results by interactively identifying additional false positive or true negative samples. Clinical evaluations of mammograms indicate the potential of using this algorithm as an effective tool to bring microcalcification areas to the attention of the radiologist during a routine reading session of mammograms.     

Effect of low-volatile additives on the structure and strength of cokes

Blends of medium-volatile or high-volatile coals have been carbonized in a 7 kg oven with low-volatile coals (6–16% VM, dmmf). A comparison is made of the strength and structural properties of these cokes with those of the cokes made under corresponding conditions from the medium or high-volatile coals alone. With increasing levels of addition of the low-volatile coals the tensile strength of the blend cokes generally attains a maximum and then decreases. These strength changes are related to changes in porosity, pore-wall thickness and pore dimensions. Coals which display some degree of plasticity and which are weakly caking improve coke quality by altering the pore-structure due to the combined effects of decreasing the pore diameter and slightly increasing the wall thickness. Those additives which are non-caking act primarily as wall thickeners.     

Ignitability of decomposed transformer fluids

The effects of an electrical field (12 KV/cm) and elevated temperature (300°C) on the ignition potential of transformer fluids, which are candidate replacements for polychlorinated biphenyls (PCBs), have been studied. The combined results indicate that the chemical composition of the fluids were alerted, often in such a manner as to increase the ease of ignition. Exploratory Fire Research Center for Fire Research national Bureau of Standards     

Dynamic Network Flow Modelling of Fixed Path Material Handling Systems

A time expanded network flow model and software for analyzing the flow traffic in dynamically loaded material handling systems with fixed paths and blocking are described. An illustration of the capabilities and limitations of the approach for evaluating alternative system concepts is provided.     

Classification of Spectral Patterns Obtained from Eustachian Tube Sonometry

Spectral patterns of sound transmission through the Eustachian tube (ET) have been obtained in a series of experiments designed to identify ET dysfunction. Previous studies of ET function using sonometry have relied on heuristic and somewhat arbitrary methods in interpreting the data. In this study, an automated classification algorithm was developed to separate these sonograms into three distinct groups. From a total of 150 sample spectra, 75 were used in the formation of learning sets. The remaining spectra were classified into these three groups using standard Bayesian techniques. Both parametric and nonparametric methods were applied in estimating conditional probability density functions. Results of classification are compared with an independent test of ET function. Agreement between our classifier and the results of the independent test was as good as 97.3 percent. The results of this study indicate that an automated classification procedure can effectively distinguish among the three major types of sonograms obtained from ET sonometry.     

Advance organizers that compensate for the organization of text.

In Exp I, 56 college students with no computer experience read a 24-frame text on computer programing that was presented in logical or random order. For random organization, Ss given an advance organizer performed better on a posttest than controls, but the opposite pattern obtained for logical organization. In Exp II, 96 students read a 4-paragraph text concerning imaginary countries that was presented in name or attribute organization. Low-ability (determined by questionnaire data on academic background and test scores) Ss given an organizer prior to reading performed better on questions that required integrating across different paragraphs of the presented text, and Ss given the organizer after reading performed relatively better on questions concerning information they had read within the same paragraph. Apparently, advance organizers served as an assimilative context for unfamiliar organizations. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multidimensional scaling analysis of schizophrenics' and normals' perceptions of verbal similarity.

Compared the judgments of similarity of words by 14 paranoid and 14 nonparanoid schizophrenics (mean ages, 29.43 and 30.64 yrs, respectively) with those by 14 normals (mean age, 32.79 yrs). The judgments were analyzed using an individual-differences multidimensional scaling procedure. A greater judgmental consistency was obtained among the normals than among the paranoid schizophrenics and larger differences among stimulus dimensions, in their contributions to predictable judgmental variance, were obtained for the normals as compared with the schizophrenics, especially the paranoid schizophrenics. Stimulus dimensions resembling the potency, activity, and evaluative dimensions of the semantic differential were less influential in the judgments of the schizophrenics, especially those classified as paranoid, than in the judgments of the normals. Results are discussed in terms of overinclusiveness among schizophrenics in multidimensional similarity judgments, as well as in terms of the potential importance to schizophrenics' deficiencies in semantic interpretations of the reduced influence of relevant dimensions of meaning. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perspectives on human performance modelling

An overview of, and perspective on, human performance modelling is presented. The role of human performance models in the design process for complex man-machine systems is discussed. Then psychologically-based models and a control-theoretic approach to modelling are reviewed. Finally, a recently developed model that illustrates how features of the two approaches may be synthesized to analyze a wider range of supervisory control problems is described and discussed.