Allocation of freeway ramp metering volumes to optimize corridor performance

A simple macroscopic freeway traffic corridor model is formulated for the purpose of developing optimal allocations of freeway on-ramp metering volumes. The model represents a freeway and a single parallel "equivalent surface street," both unidirectional, which are interconnected by freeway on-ramps. Since a choice of routes is included in the problem formulation, the fairly standard methodology of "traffic assignment" is employed to predict how drivers will react to the on-ramp metering. An explicit traffic assignment algorithm which includes ramp queueing is developed. Both the corridor and traffic assignment models are restricted to stationary traffic patterns. Two specific corridor performance criteria, freeway travel rate and total travel-time rate, are formulated in terms of the model variables. Then the problem of choosing ramp metering volumes to optimize a performance criterion is posed. A computationally efficient suboptimal dynamic programming scheme is developed and illustrated by an example.     

A comparative analysis of pulmonary perfusion scans with pulmonary angiograms

Pulmonary angiograms and pulmonary lung perfusion scans on 162 patients with pulmonary embolism were comparatively analyzed. Among the expert angiographic panel members who independently evaluated the studies there was consistent agreement on the diagnosis, size of the emboli, and severity. Consistency of agreement among the expert pulmonary lung perfusion scan panelists was considerably less. These data demonstrate that, in addition to the lack of specificity of the lung perfusion scan for the diagnosis of pulmonary thromboemboli, there is a considerable problem of interpretation in this patient population.     

The relationship between overinclusive thinking, perceptual rigidity, and the discrimination learning of new concepts.

Compared 19 newly admitted psychiatric inpatients who showed overinclusive thinking on the Payne Object Classification Test with 24 patients matched for age, IQ, and abstraction ability who were not overinclusive. In a concept-attainment experiment, contrary to prediction, overinclusive Ss did not learn overinclusive concepts. There were no significant differences between the groups. However, overinclusive Ss, as predicted, showed an abnormal lack of "Einstellung" rigidity as measured by a flexibility score from the Brengelmann Picture Recognition Test. The overinclusion score of the object classification test correlated highly (.90) with this flexibility score. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction factors for the determination of optical-fibre refractive-index profiles by the near-field scanning technique

Numerical calculations are presented of the correction factor for use with the near-field scanning method of index profile determination. It is shown that a single curve can be applied to a range of possible profiles, and a numerically obtained average curve is given.     

Space psychology and the inner sanctums.

Comments that a report by Rohles in the "American Psychologist" (1960, 15, 668-669) describes a facility for training animals in order to obtain behavioral data in space flight. The present authors feel that such a facility is indeed potentially an important part of psychology's effort in manned space flight programs. However, Rohles's report is said to contain factual errors which create the impression that, up until now, psychology has been asleep on the launching pad. The authors refer primarily to the first two paragraphs of the report, and will comment on three points. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental measurements and empirical modelling of the regional deposition of inhaled particles in humans

Regional deposition of inhaled particles was studied experimentally in a hollow cast of the human larynx-tracheobronchial tree extending through the first six branching levels, and in twenty-six non-smoker human volunteers in vivo. Results of the hollow cast study indicated a linear dependence of particle deposition efficiency on the Stokes number for aerosols with aerodynamic diameters greater than 2 micrometers. Alveolar and total respiratory tract in vitro deposition in healthy non-smokers was minimal for particles of approximately 0.4 micrometers, and alveolar deposition for mouthpieces inhalations peaked for particles of approximately 3 micrometers. A new anatomic parameter, the bronchial deposition size (BDS), is introduced to permit the classification of various individuals and populations according to their tracheobronchial deposition efficiencies. The average BDS's were 1.20 cm for 26 healthy non-smokers, 1.02 cm for 46 cigarette smokers, 0.90 cm for 19 clinical patients being treated for obstructive lung disease and 0.60 cm for six severely disabled patients.