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.     

Response of Multiwire Proportional Chambers to Relativistic Heavy Nuclei

Measurements have been carried out at the Lawrence Berkeley Laboratory Bevatron to investigate the response of multiwire proportional chambers to 2. 1 GeV/nucleon C12 and O16 nuclei. The relative gas gain as a function of high voltage was measured for three different gases: 80% Ar/20%CO2, 75% Ar/ 25%C4H10, and 81% Ar/14% Xe/5%CO2. The gas gain obtained with 5.9 KeV X-rays from Fe55 sources was also measured for comparison. Saturation characteristics of the chambers are analyzed and the implications of the results on the use of multiwire proportional chambers as spatial detectors in cosmic ray experiments are discussed. A summary of the results of delta ray calculations and their effect on spatial resolution is also presented.     

Characterization of polyvinyl chloride. Part III. An alternative GPC method for measuring the radii of gyration,and the degree of long-chain branching of polydispersed polymers

A method for measuring the unperturbed radius of gyration and the degree of long-chain branching in Gaussian-distribution polymers is proposed. Polyvinyl chloride (PVC) and polyvinyl acetate (PVAc) were selected to illustrate the method. It was observed that PVC samples prepared by homogeneous and heterogeneous polymerizations exhibit the same degree of long-chain branching. This conclusion is supported by viscometric data. The polydispersity ratios (M_w/M_n) indicate that both types of polymerizations would yield a very small amount of total branching (long chain and short chain.) The calculated unperturbed radius of gyration of linear PVC samples was found to be 0.185 \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\frac{{{\rm \dot A}^{\rm 2} {\rm mole}}}{{{\rm gm}}}} \right) $\end{document}, and that of PVAc was determined to be 0.107 \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\frac{{{\rm \dot A}^{\rm 2} {\rm mole}}}{{{\rm gm}}}} \right) $\end{document}. The value obtained for PVC is shown to be in agreement with the value determined from the viscometric method as described in our previous work.