An Error-Dependent Model of Instrument-Scanning Behavior in Commercial Airline Pilots

Since the work of Fitts and his colleagues, researchers have been using eye-movement data to evaluate various aspects of pilot instrument scanning behavior. Although Senders\u27 work indicated that link values and transitional probabilities could be accurately predicted using a random sampling process, several investigators have recently suggested that pilot scanning behavior was deterministic. However, there has been no clear empirical evidence to support a deterministic hypothesis. The present research presents a new flexible model of pilot instrument scanning behavior which assumes that the pilot uses a set of deterministic scanning patterns on (1) the pilot\u27s perception of error in the state of the aircraft, and (2) the pilot\u27s knowledge of the interactive nature of the aircraft\u27s systems. Statistical analyses revealed that a three-stage Markov process composed of the pilot\u27s three predicted lookpoints, occurring 1/30, 2/30, and 3/30 of a second prior to each LP, accurately modelled the scanning behavior of 14 commercial airline pilots while flying steep turn maneuvers in a Boeing 737 flight simulator. Furthermore, the modelled scanning data for each pilot were not statistically different from the observed scanning data in comparisons of mean dwell time, entropy, and entropy rate. These findings represent the first direct evidence that pilots are using deterministic scanning patterns during instrument flight. The results are interpreted as direct support for the error-dependent model and suggestions are made for further research that could allow for identification of the specific scanning patterns suggested by the model

A CD-ROM Based Agricultural Information Retrieval System

An information retrieval system for agricultural extension was developed using CD-ROM technology as the primary medium for information delivery. Object-oriented database techniques were used to organize the information. Conventional retrieval techniques including hypertext, fulltext searching, and relational databases, and decision support programs such as expert systems were integrated into a complete package for accessing information stored on the CDROM. A multimedia user interface was developed to provide a variety of capabilities including computer graphics and high-resolution digitized images. Information for the disk was gathered and entered using extension publications which were tagged using an SGML-based document markup language. The fully operational CD-ROM system has been implemented in all 67 county extension offices in Flori

Topology of the Spin-polarized Charge Density in bcc and fcc Iron

We investigate the topology of the spin-polarized charge density in bcc and fcc iron. While the total spin-density is found to possess the topology of the non-magnetic prototypical structures, in some cases the spin-polarized densities are characterized by unique topologies; for example, the spin-polarized charge densities of bcc and high-spin fcc iron are atypical of any known for non-magnetic materials. In these cases, the two spin-densities are correlated: the spin-minority electrons have directional bond paths with deep minima in the minority density, while the spin-majority electrons fill these holes, reducing bond directionality. The presence of two distinct spin topologies suggests that a well-known magnetic phase transition in iron can be fruitfully reexamined in light of these topological changes. We show that the two phase changes seen in fcc iron (paramagnetic to low-spin and low-spin to high-spin) are different. The former follows the Landau symmetry-breaking paradigm and proceeds without a topological transformation, while the latter also involves a topological catastrophe.Comment: 5 pages, 3 figures. Phys. Rev. Lett. (in press

Tribology: The Story of Lubrication and Wear

Topics addressed include: lubrication and design of high speed rolling element bearings, high speed gears, and traction drives

A direct empirical proof of the existence of dark matter

We present new weak lensing observations of 1E0657-558 (z=0.296), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the dissipationless stellar component and the fluid-like X-ray emitting plasma are spatially segregated. By using both wide-field ground based images and HST/ACS images of the cluster cores, we create gravitational lensing maps which show that the gravitational potential does not trace the plasma distribution, the dominant baryonic mass component, but rather approximately traces the distribution of galaxies. An 8-sigma significance spatial offset of the center of the total mass from the center of the baryonic mass peaks cannot be explained with an alteration of the gravitational force law, and thus proves that the majority of the matter in the system is unseen.Comment: Accepted for publication in ApJ

Metalinguistic tactics in the Hong Kong protest movement

This paper explores the metalinguistic tactics used by Hong Kong protesters in 2014 and 2019 and how they reflected and exploited a range of dominant ideologies about language in the city. These tactics are considered both in terms of their rhetorical utility in the “message war” between protesters and authorities, and their significance in the broader sociolinguistic context of Hong Kong. The analysis reveals how such tactics entailed both opportunities and risks, allowing protesters to create shareable discursive artifacts that spread quickly over social media and to promote in-group solidarity and distrust of their political opponents, but also limiting their ability to broaden the appeal of their messages to certain segments of the population and implicating them in upholding language ideologies that promote exclusion and marginalization

Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56

The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass distribution from both strong and weak gravitational lensing data. Multi-color, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely-calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe et al. (2004,2006a).Comment: Accepted for publication in ApJ; Version with full-resolution figures available at http://www.slac.stanford.edu/~marusa/Work/bradac_strong_weak_III.pd

Dust and Stellar Populations in the Large Magellanic Cloud

We present an analysis of line-of-sight extinction measurements obtained using data from the Magellanic Clouds Photometric Survey, which provides 4-filter photometry for millions of stars in the Large Magellanic Cloud. We find that visual extinctions are typically larger by several tenths of a magnitude for stars with effective temperatures > 12000 K, than for stars with effective temperatures between 5500 K and 6500 K. Several repercussions of this population-dependent extinction are discussed. In particular, LMC distance measurements that utilize old stellar populations (such as red clump stars), but use extinctions derived from OB stars, may be biased low. Population-dependent extinction affects the interpretation of color-magnitude diagrams and results in an effective absorption law that is steeper than that intrinsic to the dust for unresolved stellar systems. We further explore the relation between the stellar populations and dust by comparing our extinction map to the 100mu image of the region and identifying potential heating sources of the dust. We conclude that 100mu flux should be used with caution as a star formation tracer, particularly for studies of star formation within galaxies. Finally, we reproduce the observed extinction variation between the hot and cold stellar populations with a simple model of the distribution of the stars and dust where the scaleheight of the cooler stars is >> than that of the dust (which is twice that of the OB stars). (Abridged Abstract)Comment: Accepted for publication in AJ (scheduled for Dec. 1999). 31 pgs (including Figures

First Results from the High-Brightness X-Ray Spectroscopy Beamline 9.3.1 at ALS

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1–6 keV photon energy range. This beamline is designed to achieve the goal of high brightness at the sample for use in the x‐ray atomic and molecular spectroscopy (XAMS) science, surface and interface science, biology and x‐ray optical development programs at ALS. X‐ray absorption and time‐of‐flight photoemission measurements in 2–5 keV photon energy range along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented

The Ursinus Weekly, January 15, 1962

Shadowy figure of Ursinus\u27 past publishes volume of 66 poems • Dr. Snyder, Forum speaker, outlines seven strong forces in Africa today • Spontaneous fun object of new social committee • Prof casts critical eye over Lantern; Discovers sound creative instincts • Bursting water pipe sends Alumni Office to 620 Main • Student teachers\u27 light-hearted talk explains what\u27s not in the Ed. book • Best-dressed co-ed sought by Weekly • Shares of the pecuniary pie • Pre-medders hear about corneal transplant work • Editorial: Appeal of wrestling • Ursinus in the past • Letters to the editor • Obituary for a timid intellectual • Dryfoos sets two Ursinus cage marks; Dean ties record with quick pin • Pair of heartbreaking losses catch grapplers last week • Basketball begins • Frymen flounder; Lose to PMC, 92-80; Drop thriller to Swarthmore, 89 to 85 • Greek gleaningshttps://digitalcommons.ursinus.edu/weekly/1309/thumbnail.jp