Accurate detection of moving targets via random sensor arrays and Kerdock codes

The detection and parameter estimation of moving targets is one of the most important tasks in radar. Arrays of randomly distributed antennas have been popular for this purpose for about half a century. Yet, surprisingly little rigorous mathematical theory exists for random arrays that addresses fundamental question such as how many targets can be recovered, at what resolution, at which noise level, and with which algorithm. In a different line of research in radar, mathematicians and engineers have invested significant effort into the design of radar transmission waveforms which satisfy various desirable properties. In this paper we bring these two seemingly unrelated areas together. Using tools from compressive sensing we derive a theoretical framework for the recovery of targets in the azimuth-range-Doppler domain via random antennas arrays. In one manifestation of our theory we use Kerdock codes as transmission waveforms and exploit some of their peculiar properties in our analysis. Our paper provides two main contributions: (i) We derive the first rigorous mathematical theory for the detection of moving targets using random sensor arrays. (ii) The transmitted waveforms satisfy a variety of properties that are very desirable and important from a practical viewpoint. Thus our approach does not just lead to useful theoretical insights, but is also of practical importance. Various extensions of our results are derived and numerical simulations confirming our theory are presented

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 203

This bibliography lists 150 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980

Data bases and data base systems related to NASA's Aerospace Program: A bibliography with indexes

This bibliography lists 641 reports, articles, and other documents introduced into the NASA scientific and technical information system during the period January 1, 1981 through June 30, 1982. The directory was compiled to assist in the location of numerical and factual data bases and data base handling and management systems

Aeronautical engineering: A continuing bibliography with indexes (supplement 255)

This bibliography lists 529 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1990. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Farmers' preferences for East African highland cooking banana 'Matooke' hybrids and local cultivars

BackgroundAn understanding of farmers' preferences of new banana cultivars and their characteristics is critical for developing and selecting cultivars that meet consumer needs. Therefore, phenotypic selection in a genetically variable population remains an important aspect of plant breeding.MethodsThe participatory varietal selection approach for preference ranking was used on 31 'Matooke' secondary and primary triploid hybrids and local banana cultivars evaluated between 2016 and 2019 in Uganda and Tanzania to investigate how farmers' preference attributes could help breeders identify superior cultivars. The quantitative data were analyzed using the Statistical Package for Social Sciences (SPSS). The qualitative data from farmers' focus group discussions (FGDs) were described using content analysis. The Mann–Whitney U test and Wilcoxon's signed-rank test were used to confirm the difference in farmers' preferences between groups.ResultsFarmers' approaches for defining characteristics were multivariate, and their preferences varied by site and country. Large fruit, a large bunch, market acceptability of the banana bunch, a sturdy stem, and an attractive appearance of the banana plant were the characteristics most preferred by farmers in Tanzania and Uganda. Tanzanian farmers preferred large bunches over other characteristics like bunch marketability and robust stem. Large fruit, drought tolerance, a strong stem, and phenotypic similarity to local cultivars were prioritized by Ugandan farmers. Both men and women farmers were more concerned with production-related characteristics, but the former valued marketing-related characteristics more, while the latter preferred use-related characteristics. Their preferences did not differ statistically, but the relative importance assigned by each group to the selected attributes was different.ConclusionFarmers' varietal preferences are frequently based on some assumed requirements, resulting in cultivar rejection or non-adoption. Therefore, determining the value attributed to each characteristic by various farmer groups is crucial in developing 'Matooke' banana cultivars with desired attributes that will boost the rate of adoption on-farms. Breeding initiatives that establish a system of integrated approaches and rely on thorough diagnosis of both production and consumption characteristics will best serve farmers' diverse preferences. To accomplish this, planning for varietal improvement initiatives at various levels—including internationally, regionally, nationally, and locally—would require a strong participatory structure that is gender inclusive

Characterization of Xylella fastidiosa in rabbiteye blueberry

Xylella fastidiosa colonizes the xylem of a wide range of plants and causes symptoms in many of them. It was of interest to determine how widespread X. fastidiosa was and what its potential impact might be in rabbiteye blueberry. X. fastidiosa was detected from two of 17 Louisiana orchards from which samples were collected. A yield study was conducted at one of these orchards, and mean yields of X. fastidiosa-positive plants were 55% and 62% less than those of X. fastidiosa-negative plants in 2013 and 2014, respectively. Average berry weight was also lower in X. fastidiosa-positive plants. However, plants that were X. fastidiosa-negative in 2013 remained so until 2015, suggesting that the bacterium does not spread rapidly in established orchards. Regular testing of plants that had tested positive for X. fastidiosa revealed that root sap was more reliable than stem sap for detection by real-time PCR. Detection by ELISA using leaf petiole/midrib tissue or, in the winter, shoot terminals, was not as consistent as detection in root sap by real-time PCR. However, it was comparable or better in some months and was consistently as good as or better than detection in stem sap by real-time PCR, except in April, when detection by ELISA in petiole/midrib tissue cannot be relied upon. Genotypes of X. fastidiosa identified from rabbiteye blueberry in Louisiana include combinations of alleles that are believed to have resulted from recombination between X. fastidiosa subspecies multiplex and fastidiosa. One genotype (ST 42) found at two Louisiana orchards was previously identified from southern highbush blueberry in Georgia. Inoculation of seven rabbiteye cultivars and one southern highbush cultivar with an X. fastidiosa isolate from rabbiteye blueberry did not result in detected infection within nine months. X. fastidiosa warrants awareness as a possible cause of yield loss and plant decline in rabbiteye blueberry. Rabbiteye blueberry likely harbors a genotype of X. fastidiosa that is pathogenic to southern highbush blueberry, so growers should take care to use clean planting material if introducing rabbiteye plants into an orchard that contains susceptible southern highbush cultivars

Information resources management, 1984-1989: A bibliography with indexes

This bibliography contains 768 annotated references to reports and journal articles entered into the NASA scientific and technical information database 1984 to 1989