Measurement accuracy in control of segmented-mirror telescopes

Design concepts for future large optical telescopes have highly segmented primary mirrors, with the out-of-plane degrees of freedom actively controlled. We estimate the contribution to errors in controlling the primary mirror that results from sensor noise and, in particular, compare mechanical measurements of relative segment motion with optical wave-front information. Data from the Keck telescopes are used to obtain realistic estimates of the achievable noise due to mechanical sensors. On the basis of these estimates, mechanical sensors will be more accurate than wave-front information for any of the telescope design concepts currently under consideration, and therefore supplemental wave-front sensors are not required for real-time figure control. Furthermore, control system errors due to sensor noise will not significantly degrade either seeing-limited or diffraction-limited observations.     

Digital filtering implementations for the detection of broad spectral features by direct analysis of passive Fourier transform infrared interferograms

Finite impulse response (FIR) filters and finite impulse response matrix (FIRM) filters are evaluated for use in the detection of volatile organic compounds with wide spectral bands by direct analysis of interferogram data obtained from passive Fourier transform infrared (FT-IR) measurements. Short segments of filtered interferogram points are classified by support vector machines (SVMs) to implement the automated detection of heated plumes of the target analyte, ethanol. The interferograms employed in this study were acquired with a downward-looking passive FT-IR spectrometer mounted on a fixed-wing aircraft. Classifiers are trained with data collected on the ground and subsequently used for the airborne detection. The success of the automated detection depends on the effective removal of background contributions from the interferogram segments. Removing the background signature is complicated when the analyte spectral bands are broad because there is significant overlap between the interferogram representations of the analyte and background. Methods to implement the FIR and FIRM filters while excluding background contributions are explored in this work. When properly optimized, both filtering procedures provide satisfactory classification results for the airborne data. Missed detection rates of 8% or smaller for ethanol and false positive rates of at most 0.8% are realized. The optimization of filter design parameters, the starting interferogram point for filtering, and the length of the interferogram segments used in the pattern recognition is discussed.     

A unified modeling and solution framework for combinatorial optimization problems

Combinatorial optimization problems are often too complex to be solved within reasonable time limits by exact methods, in spite of the theoretical guarantee that such methods will ultimately obtain an optimal solution. Instead, heuristic methods, which do not offer a convergence guarantee, but which have greater flexibility to take advantage of special properties of the search space, are commonly a preferred alternative. The standard procedure is to craft a heuristic method to suit the particular characteristics of the problem at hand, exploiting to the extent possible the structure available. Such tailored methods, however, typically have limited usefulness in other problems domains.An alternative to this problem specific solution approach is a more general methodology that recasts a given problem into a common modeling format, permitting solutions to be derived by a common, rather than tailor-made, heuristic method. Because such general purpose heuristic approaches forego the opportunity to capitalize on domain-specific knowledge, they are characteristically unable to provide the effectiveness or efficiency of special purpose approaches. Indeed, they are typically regarded to have little value except for dealing with small or simple problems.This paper reports on recent work that calls this commonly held view into question. We describe how a particular unified modeling framework, coupled with latest advances in heuristic search methods, makes it possible to solve problems from a wide range of important model classes.Correspondence to: Gary A. Kochenberger.This research was supported in part by ONR grants N000140010598 and N000140310621.     

Computer vision techniques for traffic flow computation

This paper describes an application of computer vision techniques to road surveillance. It reports on a project undertaken in collaboration with the Research and Innovation group at the Ordnance Survey. The project aims to produce a system that detects and tracks vehicles in real traffic scenes to generate meaningful parameters for use in traffic management. The system has now been implemented using two different approaches: a feature-based approach that detects and groups corner features in a scene into potential vehicle objects, and an appearance-based approach that trains a cascade of classifiers to learn the appearances of vehicles as an arrangement of a set of pre-defined simple Haar features. Potential vehicles detected are then tracked through an image sequence, using the Kalman filter motion tracker. Experimental results of the algorithms are presented in this paper.     

Effects of cerebellar lesions on activity, social interactions, and other motivated behaviors in the rat.

In a total of 36 male rats, lesions of the cerebellar fastigial nucleus, but not lateral nuclear lesions or cerebellar cortical lesions, resulted in significant reductions in activity, open-field exploratory behavior, and social interactions. These deficits showed no recovery over a 4-wk testing period and were not related to the motor effects of the lesions. Other motivated behaviors (e.g., eating, grooming, gnawing, and pain responsiveness) were minimally affected. Results suggest the existence of 2 separate fastigial output pathways to neurobehavioral substrates: (a) the direct fastigio-bulbar pathway, which mediates the eating, grooming, and gnawing behaviors elicited by fastigial stimulation, and (b) the ascending fastigial projection to limbic structures, which may mediate fastigial influences on activity and social interaction. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An examination of common concerns about rational–emotive therapy.

Examines some of the more frequent concerns and criticisms about rational–emotive therapy, including issues of relationship factors, emotive aspects, values, religious concerns, and intervention techniques and styles in therapy. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locus of control and mastery in a reformatory: A field study of defensive externality.

145 males (mean age 21.9 yrs) enrolled in an incentive-based reformatory were administered Rotter's Internal–External Locus of Control (LOC) Scale, Marlowe–Crowne Social Desirability Scale, and several measures of expectancy/importance of success and failure. After success or failure at mastery attempts, Ss made causal attributions derived from both J. B. Rotter's (1966) and B. Weiner's (1972) theories. Results show that internal LOC inmates, relative to externals, demonstrated greater mastery and attributed more responsibility to themselves for success, even with social desirability controlled. Defensive externality hypotheses involving both major moderators of LOC, interpersonal trust and action taking, as well as 4 proposed aspects of defensive externality were not supported. Contrary to predictions, trust-defensive externals made more internal nondefensive attributions after failure than trust-congruent externals did. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A developmental study of learned helplessness.

Examined susceptibility to learned helplessness among 20 children from each of kindergarten, Grade 1, Grade 3, and Grade 5 classes by exposing groups of Ss to either repeated failure or repeated success on hidden figures problems. Helplessness was measured by Ss' persistence in looking for hidden figures and their capacity to find them following repeated success or failure. It was hypothesized that younger Ss would be less susceptible to helplessness than older ones, due to age-related differences in causal attributions for success and failure. Results confirm the hypothesis in that failure, relative to success, had significantly less influence on the level of helplessness in younger Ss' behavior. It is suggested that the development of attributional capabilities during the preschool and early elementary school years has important ramifications for cognitive theories of motivation. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On finding minimal-length test sets for diagnosing faults in combinational circuits

A fault-detection matrix contains sufficient information for finding minimal-length, fault-diagnosis test sets. The necessary and sufficient condition is that the submatrix of the fault-detection matrix must not contain equal rows. Cited examples demonstrate that characteristics in the fault-detection matrix can be used to facilitate the search for tests.