12,741 research outputs found

    Optimal periodic binary codes of lengths 28 to 64

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    Results from computer searches performed to find repeated binary phase coded waveforms with optimal periodic autocorrelation functions are discussed. The best results for lengths 28 to 64 are given. The code features of major concern are where (1) the peak sidelobe in the autocorrelation function is small and (2) the sum of the squares of the sidelobes in the autocorrelation function is small

    A trajectory preprocessor for antenna pointing

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    A trajectory-preprocessing algorithm has been devised which matches antenna angular position, velocity, and acceleration to those of a target. This eliminates vibrations of the antenna structure caused by discontinuities in velocity and acceleration commands, and improves antenna-pointing performance by constraining antenna motion to a linear regime. The algorithm permits faster acquisition times and preserves antenna-tracking capability in situations where there would otherwise be an unacceptably sudden change in antenna velocity or acceleration. A simulation of DSS 13 shows that this preprocessor would reduce servo error to 1 mdeg during acquisition of a low-Earth-orbiting satellite

    Three dimensional tracking with misalignment between display and control axes

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    Human operators confronted with misaligned display and control frames of reference performed three dimensional, pursuit tracking in virtual environment and virtual space simulations. Analysis of the components of the tracking errors in the perspective displays presenting virtual space showed that components of the error due to visual motor misalignment may be linearly separated from those associated with the mismatch between display and control coordinate systems. Tracking performance improved with several hours practice despite previous reports that such improvement did not take place

    Nutritive Value of South-Central Kentucky Forbs

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    South Central Kentucky pastures serve as a host for a plethora of forbs found throughout the Upper South and Midwest United States. In this region, forbs can be numerous within pastures that are under- managed. Many producers view forbs as unwanted or weedy species and may not fully understand the value that some of these forbs provide to beef cattle. With little scientific information found on the subject for the specific geographic area, the purpose of this study was to determine what types of forbs will provide adequate nutrition for lactating beef cows. Three pastures from separate farms were used for this study. Botanical composition was assessed monthly starting in March and continuing through October 2022. Vegetative material from the five most numerous forbs was collected along with tall fescue, a predominate perennial forage, and submitted to a forage lab for quality testing using wet chemistry. Crude protein (CP), total digestible nutrients (TDN), sodium (Na), and copper (Cu) were reported for this presentation. The forbs were classified as palatable and non-palatable and compared to tall fescue. The results showed indicate the palatable forbs and tall fescue generally supported the nutritional requirement of a lactating beef cow. Overall, palatable forbs showed a higher TDN, CP, and Cu levels in comparison to tall fescue and the non-palatable forbs. In summary, it was found palatable forbs retained higher nutritive value than tall fescue and non-palatable forbs and met the nutritional requirements for a lactating beef cow apart from Na

    Researching trust in the police and trust in justice: a UK perspective

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    This paper describes the immediate and more distant origins of a programme of comparative research that is examining cross-national variations in public trust in justice and in the police. The programme is built around a module of the fifth European Social Survey, and evolved from a study funded by the European Commission. The paper describes the conceptual framework within which we are operating – developed in large measure from theories of procedural justice. It reviews some of the methodological issues raised by the use of sample surveys to research issues of public trust in the police, public perceptions of institutional legitimacy and compliance with the law. Finally it gives a flavour of some of the early findings emerging from the programme
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