3,717 research outputs found
A rule-based system for real-time analysis of control systems
An approach to automate the real-time analysis of flight critical health monitoring and system status is being developed and evaluated at the NASA Dryden Flight Research Facility. A software package was developed in-house and installed as part of the extended aircraft interrogation and display system. This design features a knowledge-base structure in the form of rules to formulate interpretation and decision logic of real-time data. This technique has been applied for ground verification and validation testing and flight testing monitoring where quick, real-time, safety-of-flight decisions can be very critical. In many cases post processing and manual analysis of flight system data are not required. The processing is described of real-time data for analysis along with the output format which features a message stack display. The development, construction, and testing of the rule-driven knowledge base, along with an application using the X-31A flight test program, are presented
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A new Lyropecten (Pectinidae, Bivalvia, Mollusca) from the central California Miocene, USA
A new pectinid, Lyropecten terrysmithae n. sp., has been recognized in middle to late Miocene rock units referred to as the Monterey Formation and Santa Margarita Sandstone in the southern Salinas Valley, central California. Previously, L. terrysmithae had been identified as a flat form belonging to either L. estrellanus or L. catalinae, then more recently to Argopecten sp. The earlier assignments were based on its moderate size and a radial rib count nearly identical to these taxa. However, its hinge, flat unledged valves, looped lamellar growth lines, and hinge crura set L. terrysmithae apart from Argopecten and all species of Lyropecten. Localities where it occurs in the Salinas Valley that can be accurately dated are from the late middle to middle late Miocene “Margaritan” California provincial molluscan stage. While L. terrysmithae has been collected at other sites, those localities lack diagnostic age-specific species necessary to determine an accurate geological age and maybe older
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My work explores the relationship of text and image to the creation and perception of our roles in the world, principally from a feminist point of view. I examine the influence of symbols and labels, both imposed and carefully chosen, on the identity women present to the world and ourselves. Through photography and design, I reflect on the roles I fill in my own life as an artist, wife, mother, and daughter and the symbols and words associated with such roles in the hope of revealing a larger truth about communication and relationships through words and images
Tiree Tales: A Co-operative Inquiry into the Poetics of Location-Based Narratives
In a location-based story a reader's movement through physical space is translated into movement through narrative space, typically by presenting them with text fragments on a smart device triggered by location changes. Despite the increasing popularity of such systems their poetics are poorly understood, meaning limited guidance for authors, and few authoring tools. To explore these poetics we present a co-operative inquiry into the authoring of an interactive location-based narrative, `The Isle of Brine', set on the island of Tiree. Our inquiry reveals both pragmatic and aesthetic considerations driven by the locations themselves, that affect the design of both the Story (narrative structure) and Fabula (events within the story). These include the importance of paths, bottlenecks, and junctions as a physical manifestation of calligraphic patterns, the need for coherent narrative areas, and the requirement to use evocative places and to manage thematic and tonal discord between the landscape and the narrative
Unexpected evolutionary proximity of eukaryotic and cyanobacterial enzymes responsible for biosynthesis of retinoic acid and its oxidation
Biosynthesis of retinoic acid from retinaldehyde (retinal) is catalysed by an aldehyde dehydrogenase (ALDH) and its oxidation by cytochrome P450 enzymes (CYPs). Herein we show by phylogenetic analysis that the ALDHs and CYPs in the retinoic acid pathway in animals are much closer in evolutionary terms to cyanobacterial orthologs than would be expected from the standard models of evolution
Virus isolation studies suggest short-term variations in abundance in natural cyanophage populations of the Indian Ocean
Cyanophage abundance has been shown to fluctuate over long timescales and with depth, but little is known about how it varies over short timescales. Previous short-term studies have relied on counting total virus numbers and therefore the phages which infect cyanobacteria cannot be distinguished from the total count.
In this study, an isolation-based approach was used to determine cyanophage abundance from water samples collected over a depth profile for a 24 h period from the Indian Ocean. Samples were used to infect Synechococcus sp. WH7803 and the number of plaque forming units (pfu) at each time point and depth were counted. At 10 m phage numbers were similar for most time-points, but there was a distinct peak in abundance at 0100 hours. Phage numbers were lower at 25 m and 50 m and did not show such strong temporal variation. No phages were found below this depth. Therefore, we conclude that only the abundance of phages in surface waters showed a clear temporal pattern over a short timescale. Fifty phages from a range of depths and time points were isolated and purified. The molecular diversity of these phages was estimated using a section of the phage-encoded psbD gene and the results from a phylogenetic analysis do not suggest that phages from the deeper waters form a distinct subgroup
Airborne observed solar elevation and row direction effects on the near-IR/red ratio of cotton
An airborne multispectral scanner was used to obtain data over two adjacent cotton fields having rows perpendicular to one another, at three times of day (different solar elevations), and on two dates (different plant size). The near IR/red ratios were displayed in image form, so that within-field variations and differences between fields could be easily assessed. The ratio varied with changing Sun elevation for north-south oriented rows, but no variation was detected for east-west oriented rows
Multilevel measurements of surface temperature over undulating terrain planted to barley
A ground and aircraft program was conducted to extend ground based methods for measuring soil moisture and crop water stress to aircraft and satellite altitudes. A 260ha agricultural field in California was used over the 1977-78 growing season. For cloud free days ground based temperature measurements over bare soil were related to soil moisture content. Water stress resulted from too much water, not from lack of it, as was expected. A theoretical examination of the canopy air temperature difference as affected by vapor pressure deficit and net radiation was developed. This analysis shows why surface temperatures delineate crop water stress under conditions of low humidity, but not under high humidity conditions. Multilevel temperatures acquired from the ground, low and high altitude aircraft, and the Heat Capacity Mapping Mission (HCMM) spacecraft were compared for two day and one night overpasses. The U-2 and low altitude temperatures were within 0.5 C. The HCMM data were analyzed using both the pre- and post-launch calibrations, with the former being considerably closer in agreement with the aircraft data than the latter
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