Seeing the mean: Ensemble coding for sets of faces.

We frequently encounter groups of similar objects in our visual environment: a bed of flowers, a basket of oranges, a crowd of people. How does the visual system process such redundancy? Research shows that rather than code every element in a texture, the visual system favors a summary statistical representation of all the elements. The authors demonstrate that although it may facilitate texture perception, ensemble coding also occurs for faces—a level of processing well beyond that of textures. Observers viewed sets of faces varying in emotionality (e.g., happy to sad) and assessed the mean emotion of each set. Although observers retained little information about the individual set members, they had a remarkably precise representation of the mean emotion. Observers continued to discriminate the mean emotion accurately even when they viewed sets of 16 faces for 500 ms or less. Modeling revealed that perceiving the average facial expression in groups of faces was not due to noisy representation or noisy discrimination. These findings support the hypothesis that ensemble coding occurs extremely fast at multiple levels of visual analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of surface roughness anisotropy on mismatched InAIAs/lnP heterostructures

We have studied surface roughness on mismatched In_0.65Al_0.35As epilayers of various thicknesses on (001) InP. The sample set spans the entire range from coherently strained to completely relaxed epilayers. As characterization tools, we have used atomic force microscopy (AFM), laser light scattering (LLS), and variable azimuthal angle ellipsometry (VAAE). AFM reveals that the surfaces are covered by densely packed ellipsoidal islands elongated along the [1-10] direction. The island size increases with layer thickness. Island anisotropy and the root mean square of the surface roughness increase with increasing thickness but decrease upon full lattice relaxation. LLS intensity displays a prominent azimuthal dependence that correlates well with the two-dimensional power spectrum of the surface topography, as predicted by theory. VAAE reveals a sinusoidal dependence of the ellipsometric parameter Δ on azimuthal angle. The amplitude of A correlates well with the short wavelength anisotropy of the surface power spectrum. Our work suggests that LLS and VAAE are fast, nondestructive, sensitive techniques for characterization of surface roughness in mismatched III-V heterostructures.     

Criteria for obtaining and interpreting breast thermagrams

The thermal and graphic criteria which should be used to evaluate breast thermograms are outlined. Thermograms are then categorized as normal, suspicious, or abnormal on the basis of the criteria outlined. It is hoped that these criteria can be used widely to standardize breast thermographic evaluation.     

Relation of social competence to scores on two scales of psychosis proneness.

Predicted that college students who were high on physical anhedonia and perceptual aberration would have poor social competence. The prediction followed from clinical reports that these characteristics are found in psychosis-prone individuals, a group also described as having poor social competence. Anhedonia and perceptual aberration were measured by the true–false scales of L. J. Chapman et al (1976), and social competence was measured by the Interpersonal Behavior Role-Playing Test (J. B. Goldsmith and R. M. McFall, 1975). The 16 anhedonic Ss were less socially skilled than the 19 control Ss (p?     

Mobile technology, compensatory aids, and usability evaluations

The article describes two different research projects. The first one explores the challenges of using mobile wireless devices to develop compensatory aids for people with cognitive impairments. The second contribution presents a research effort aimed at developing and evaluating context-aware mobile services.     

Key Challenges of Military Tactical Networking and the Elusive Promise of MANET Technology

Mobile ad hoc networks (MANETs) are considered by many as fundamental to realizing the global information grid (GIG) and the vision of network-centric warfare. Indeed, a fully realized MANET would be powerful in enabling highly mobile, highly responsive, and quickly deployable tactical forces. However, significant technical challenges remain before this realization is viable. Addressing these deficiencies is a significant task that will require the invention and adoption of new technology. The goal of this article is not to declare these capabilities impossible to achieve. Rather, it is to manage the expectation of the capabilities achievable in the foreseeable future through edification on the technical difficulties standing between current technology and the desired capabilities. This article provides an overview of the military MANET problem space, describing the ideal military MANET solution. Several deficiencies are highlighted that exist between MANET technologies and the desired capability. Identified technical issues include system-level architecture, routing (both interior and exterior), management, security, and medium access control (MAC), with an emphasis on the former two areas     

On the mechanism of catalysis of the Boudouard reaction by alkali-metal compounds

The mechanism of catalysis of the Boudouard (C-CO₂) reaction by the alkali-metal compounds appears to involve gaseous intermediates M(g), CO(g) and CO₂(g) where M(g) may be Li, K, Na, etc. The cyclical mechanism M(g)→ M₂CO₃→ M(g) withstood the rigorous thermodynamic analysis presented here and may be regarded as the most likely mechanism. Detailed calculations showed that formation of intercalation compounds of the type C_2nM is not very likely except at very high temperatures (1400 K and above) and under nearly pure CO environments. Thus the likelihood of intercalation compound mechanism being valid is not substantial except under stringent conditions as noted. The electrochemical mechanism probably operates parallel to the cyclic mechanism; and its relative contribution to the overall reaction is not known at this time.     

A comparison of impression and compression creep behavior of polycrystalline Sn

This paper reports on the application of a miniaturized impression creep test to measure the creep behavior of pure polycrystalline Sn, and compares the results to compression creep data on the same sample, in order to experimentally determine a scaling constant to formulate the equivalent uniaxial creep constitutive law from the impression creep data. The creep parameters determined via impression and compression creep are found to be identical, with n ∼ 5 and Q ∼ 42 kJ/mol, indicating that over the tested stress–temperature range, the mechanism is core diffusion controlled dislocation creep. In conjunction with results from previous modeling work, a single conversion factor, κⁿ/C, which depends on material properties, is shown to be usable for converting the impression creep relation to the equivalent uniaxial creep relation, and the experimentally determined value of κⁿ/C for polycrystalline Sn is very close to that obtained via modeling.

---