33,540 research outputs found
Threat perception while viewing single intruder conflicts on a cockpit display of traffic information
Subjective estimates of the threat posed by a single intruder aircraft were determined by showing pilots photographs of a cockpit display of traffic information. The time the intruder was away from the point of minimum separation was found to be the major determinant of the perception of threat. When asked to choose a maneuver to reduce the conflict, pilots selected maneuvers with a bias toward those that would have kept the intruders in sight had they been visible out the cockpit window
Successive Combination Jet Algorithm For Hadron Collisions
Jet finding algorithms, as they are used in and hadron collisions,
are reviewed and compared. It is suggested that a successive combination style
algorithm, similar to that used in physics, might be useful also in
hadron collisions, where cone style algorithms have been used previously.Comment: 18 pages plus four uuencoded postscript figures, REVTEX 3.0,
CERN-TH.6860/9
Jet Investigations Using the Radial Moment
We define the radial moment, , for jets produced in hadron-hadron
collisions. It can be used as a tool for studying, as a function of the jet
transverse energy and pseudorapidity, radiation within the jet and the quality
of a perturbative description of the jet shape. We also discuss how
non-perturbative corrections to the jet transverse energy affect .Comment: 14 pages, LaTeX, 6 figure
Effect of field of view and monocular viewing on angular size judgements in an outdoor scene
Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators
Neutrino Masses, Mixing Angles and the Unification of Couplings in the MSSM
In the light of the gathering evidence for neutrino
oscillations, coming in particular from the Super-Kamiokande data on
atmospheric neutrinos, we re-analyze the unification of gauge and Yukawa
couplings within the minimal supersymmetric extension of the Standard Model
(MSSM). Guided by a range of different grand-unified models, we stress the
relevance of large mixing in the lepton sector for the question of bottom-tau
Yukawa coupling unification. We also discuss the dependence of the favoured
value of on the characteristics of the high-energy quark and lepton
mass matrices. In particular, we find that, in the presence of large lepton
mixing, Yukawa unification can be achieved for intermediate values of
that were previously disfavoured. The renormalization-group
sensitivity to the structures of different mass matrices may enable Yukawa
unification to serve as a useful probe of GUT models.Comment: 29 pages, latex, 5 figure
Avoidance maneuevers selected while viewing cockpit traffic displays
Ten airline pilots rates the collision danger of air traffic presented on cockpit displays of traffic information while they monitored simulated departures from Denver. They selected avoidance maneuvers when necessary for separation. Most evasive maneuvers were turns rather than vertical maneuvers. Evasive maneuvers chosen for encounters with low or moderate collision danger were generally toward the intruding aircraft. This tendency lessened as the perceived threat level increased. In the highest threst situations pilots turned toward the intruder only at chance levels. Intruders coming from positions in front of the pilot's own ship were more frequently avoided by turns toward than when intruders approached laterally or from behind. Some of the implications of the pilots' turning-toward tendencies are discussed with respect to automatic collision avoidance systems and coordination of avoidance maneuvers of conflicting aircraft
Dynamical Formation of Horizons in Recoiling D Branes
A toy calculation of string/D-particle interactions within a world-sheet
approach indicates that quantum recoil effects - reflecting the gravitational
back-reaction on space-time foam due to the propagation of energetic particles
- induces the appearance of a microscopic event horizon, or `bubble', inside
which stable matter can exist. The scattering event causes this horizon to
expand, but we expect quantum effects to cause it to contract again, in a
`bounce' solution. Within such `bubbles', massless matter propagates with an
effective velocity that is less than the velocity of light in vacuo, which may
lead to observable violations of Lorentz symmetry that may be tested
experimentally. The conformal invariance conditions in the interior geometry of
the bubbles select preferentially three for the number of the spatial
dimensions, corresponding to a consistent formulation of the interaction of D3
branes with recoiling D particles, which are allowed to fluctuate independently
only on the D3-brane hypersurface.Comment: 25 pages LaTeX, 4 eps figures include
Compactification and Supersymmetry Breaking in M-theory
Keeping N=1 supersymmetry in 4-dimension and in the leading order, we disuss
the various orbifold compactifications of M-theory suggested by Horava and
Witten on , , , and the compactification by
keeping singlets under symmetry, then the compactification
on . We also discuss the next to leading order K\"ahler potential,
superpotential, and gauge kinetic function in the case. In addition,
we calculate the SUSY breaking soft terms and find out that the universality of
the scalar masses will be violated, but the violation might be very small.Comment: 16 pages, latex, no figure
Synchrotron Radiation and Quantum Gravity
Photons may evade a synchrotron radiation constraint on quantum gravity by
violating the equivalence principle.Comment: 4 pages. Comment on Jacobson et al astro-ph/0212190. Presentation
revised for brief communication to Nature with extended bibliograph
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