arXiv subjects

Paul Graham

Publications and source records attributed to Paul Graham.

3 recordsLinked to original sources

arXiv2023

VidereX: A Navigational Application inspired by ants

Navigation is a crucial element in any person's life, whether for work, education, social living or any other miscellaneous reason; naturally, the importance of it is universally recognised and valued. One of the critical components of navigation is vision, which facilitates movement from one place to another. Navigating unfamiliar settings, especially for the blind or visually impaired, can pose significant challenges, impacting their independence and quality of life. Current assistive travel solutions have shortcomings, including GPS limitations and a demand for an efficient, user-friendly, and portable model. Addressing these concerns, this paper presents VidereX: a smartphone-based solution using an ant-inspired navigation algorithm. Emulating ants' ability to learn a route between nest and feeding grounds after a single traversal, VidereX enables users to rapidly acquire navigational data using a one/few-shot learning strategy. A key component of VidereX is its emphasis on active user engagement. Like ants with a scanning behaviour to actively investigate their environment, users wield the camera, actively exploring the visual landscape. Far from the passive reception of data, this process constitutes a dynamic exploration, echoing nature's navigational mechanisms.

cs.HC↗

arXiv1993

$Π$ in the Sky ? Microwave Anisotropies from Cosmic Defects

High resolution maps of the anisotropy of the microwave sky will yield invaluable clues as to the mechanisms involved in cosmic structure formation. One fundamental question they should answer is whether the fluctuations were Gaussian random noise, as predicted in inflationary models, or were nonGaussian as in theories based on symmetry breaking and cosmic defects. In the latter case there is the prospect of obtaining information regarding symmetry breaking at high energy scales, specifically the homotopy classes $Π_n$ of the vacuum manifold. In this paper we report on detailed calculations of the degree scale anisotropies predicted in the cosmic string, monopole texture and nontopological texture theories of structure formation, emphasising their distinct character from those predicted by inflation, and the bright prospects for experimental tests.

hep-ph↗

arXiv1993

A Simple Test for Non-Gaussianity in CMBR Measurements

We propose a set of statistics $S_q$ for detecting non-gaussianity in CMBR anisotropy data sets. These statistics are both simple and, according to calculations over a space of linear combinations of three-point functions, nearly optimal at detecting certain types of non-gaussian features. We apply $S_3$ to the UCSB SP91 experiment and find that the mean of the four frequency channels is by this criterion strongly non-gaussian. Such an observation would be highly unlikely in a gaussian theory with a small coherence angle, such as standard ($n=1$, $Ω_b = .05$, $h = .5$) inflation. We cannot conclude that the non-gaussianity is cosmological in origin, but if we assume it due instead to foreground contamination or instrumental effects, and remove the points which are clearly responsible for the non-gaussian behavior, the rms of the remaining fluctuations is too small for consistency with standard inflation. Further data are needed before definitive conclusions may be drawn. Finally, we generalize the ideas behind this statistic to other types of non-gaussian behavior that might be detected in other experimental schemes.

hep-ph↗