Cent Of Signal Research Articles

OUP accepted manuscript

ABSTRACT Citizen science is a powerful analysis tool, capable of processing large amounts of data in a very short time. To bridge the gap between classification data products from web-based citizen science platforms to statistically robust signal significance scores, we present the Search Algorithm for Transits in the Citizen science Hunt for Exoplanets in Light curves (satchel) pipeline. This open source, customizable pipeline was constructed to identify and assign significance estimates to one-dimensional features marked by volunteers. We describe the functional capabilities of the satchel pipeline through application to features in photometric time-series data from the Kepler Space Telescope, classified by volunteers as part of the Planet Hunters citizen science project hosted on the Zooniverse platform. We evaluate the satchel pipeline’s overall performance based on recovery of known signals (both simulations and signals corresponding to official Kepler Objects of Interest) and relative contamination by spurious features. We find that, for a range of pipeline hyperparameters and with a reasonable score cutoff, satchel is able to recover volunteer identifications of over 98 per cent of signals from simulations corresponding to exoplanets >2 R⊕ in radius and about 85 per cent of signals corresponding to the same size range of KOIs. satchel is transparently adaptable to other citizen science classification data sets and available on GitHub.

Objective assessment of the NOAA global vegetation index data product

Abstract For the last 10 years the U.S. National Oceanic and Atmospheric Administration has produced an experimental Global Vegetation Index (GVI) data set for terrestrial vegetation research. These data, sampled from advanced very high resolution radiometer (AVHRR) observations, have served as a primary stimulus for global-scale vegetation research but have, so far, not been adequately evaluated. This study reviews the GVI production procedures and compares the resultant observations with a more comprehensive compilation of the AVHRR data being produced at the NASA Goddard Space Flight Center. There are many aspects of the GVI production procedures which could be improved to achieve the desired objectives. In particular, the mapping and sampling procedures employed provide measurements which only approximate the observed GAC measurements. The GVI NDVI record varies more than ±NDVI units (∼ 7 per cent of signal) from the GAC record and, in general, seriously underestimates the GAC NDVI measurements. The N...

Characteristics of a selectively shielded p-Si detector in 60Co and 8 and 16 MV roentgen radiation.

A p-silicon semiconductor detector with a filter of wolfram powder mixed with epoxy, that entirely covered the back of the detector, was investigated and compared with ionization chambers and an unshielded semiconductor detector. Relative depth and profile distributions obtained as signals from the semiconductors were compared with corresponding dose distributions measured with the ionization chambers in 60Co, 8 and 16 MV roentgen radiation of different field sizes. It was found that relative signal distributions from the shielded semiconductor detector agreed, within 1 per cent of the maximum signal, to the depth dose curves and that the relative signal in profile distributions also agreed, within 1 mm or 1 per cent of the signal at the central axis, as compared with dose measurements with a cylindrical, thimble ionization chamber. The relative signal in the building-up region was compared with a plane parallel ionization chamber with a deviation corresponding to a position of less than 1 mm.

Monitoring of Complex Visual Displays— II. Effects of Visual Load and Response Complexity on Human Vigilance

A vigilance experiment was performed on the characteristics of visual monitoring behavior in complex tasks like those found in modern semi-automatic systems. The activationist hypothesis, which contends that human alertness is a function of stimulation level, served as framework for the experiment. Under investigation were sources of environmental and response-produced stimulation that might he related to hitman alertness. A. simulated semi-automatic air defense surveillance task was used. Environmental stimulation was manipulated by requiring six or thirty-six visual stimulus sources to be monitored for a 3-hr observation period. Response-produced stimulation was a function of response complexity. No vigilance decrement was found for per cent of signals correctly detected. Response latency declined significantly, but slightly, for groups that had simple response conditions but not for groups with complex response requirements. Results were discussed in terms of issues in operationally defining sources of stimulation for the activationist hypothesis, and the cautions that must be observed in generalising from the simple tasks of most vigilance experiments to the complex tasks of semi-automatic systems.