4,642 research outputs found
Computer Vision Based Object Detection and Tracking in Micro Aerial Vehicles
The ultimate goal of Computer Vision is to instruct a computer to understand and interpret visual signals and images in real time and to instruct a computer to react to the environment around them. In this work, we describe a system that allows a micro aerial vehicle (MAV), equipped with an onboard camera, to detect and track a moving target object. In an alternative implementation, the MAV instead searches the environment for the target object and flies to it. Due to the limited capability of the drone’s integrated processor, image processing is performed by a ground-based computer that also determines the necessary flight corrections and communicates them to the vehicle. The complete system, comprised of the MAV, off-board computer, and software, operates autonomously, a necessary condition for many of the applications for which such systems may be useful
Inter-Annual Variability in Pasture Herbage Accumulation in Temperate Dairy Regions: Causes, Consequences, and Management Tools
Inter-annual variation in pasture herbage accumulation rate (HAR) is common in temperate dairy regions, posing challenges for farmers in the management of dairy cow feeding and of pasture state. This paper reviews the biophysical factors that cause inter-annual variation, considers some of its consequences for the efficient harvest of pasture, and discusses the basis for decision rules and support tools that are available to assist New Zealand and Australian farmers to help manage the consequences of an imbalance between feed supply and demand. These tools are well-grounded in scientific research and farmer experience, but are not widely used in the Australasian dairy industries. Some of the reasons for this are discussed. Inter-annual variability in HAR cannot be removed, even with inputs such as irrigation, but reliable forecasts of pasture HAR for a month or more could greatly improve the effectiveness of operational and tactical decision-making. Various approaches to pasture forecasting, based on pasture growth simulation models, are presented and discussed. Some of these appear to have reasonable predictive ability. However, considerably more development work is needed to: (1) prove their effectiveness; and (2) build the systems required to capture real-time, on farm data for critical systems variables such as pasture herbage mass and soil water content to combine with daily weather data. This technology presents an opportunity for farmers to gain greater control over variability in pasture-based dairy systems and improve the efficiency of resource use for profit and environmental outcomes
Computer-Based Forage Management Tools: Historical, Current, and Future Applications
Forage management has been an important human activity since the beginning of civilization. By comparison, the personal computer has been available only in the immediate past. The software developed to deal with the complexity of climate, soil, plant, animal, and socioeconomic factors has seen huge changes in a few decades. Mainframe computers facilitated numerical calculations for exploring relationships among dozens of variables. Personal computers opened the door for more individual scientist creativity and routine communication. Web-based communication globalised the option for multidisciplinary teams to tackle problems. Forage-related computer applications abound, allowing farmers, ranchers, and others to more effectively manage the land. This paper describes historical, current, and future computer-based applications that improve understanding and efficiency leading to more economically and environmentally sustainable forage-livestock systems
Density Variations in the NW Star Stream of M31
The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the
M31-M33 system has found a star stream which extends about 120 kpc NW from the
center of M31. The great length of the stream, and the likelihood that it does
not significantly intersect the disk of M31, means that it is unusually well
suited for a measurement of stream gaps and clumps along its length as a test
for the predicted thousands of dark matter sub-halos. The main result of this
paper is that the density of the stream varies between zero and about three
times the mean along its length on scales of 2 to 20 kpc. The probability that
the variations are random fluctuations in the star density is less than 10^-5.
As a control sample we search for density variations at precisely the same
location in stars with metallicity higher than the stream, [Fe/H]=[0, -0.5] and
find no variations above the expected shot noise. The lumpiness of the stream
is not compatible with a low mass star stream in a smooth galactic potential,
nor is it readily compatible with the disturbance caused by the visible M31
satellite galaxies. The stream's density variations appear to be consistent
with the effects of a large population of steep mass function dark matter
sub-halos, such as found in LCDM simulations, acting on an approximately 10Gyr
old star stream. The effects of a single set of halo substructure realizations
are shown for illustration, reserving a statistical comparison for another
study.Comment: ApJ revised version submitte
Inhaler Devices for Delivery of LABA/LAMA Fixed-Dose Combinations in Patients with COPD
Published 13th March 2019. Issue Date June 2019. Funding. The preparation of this manuscript was funded by Novartis Pharma AG. No funding or sponsorship was recieved for the publication of this article. Medical Writing and Editorial Assistance The authors thank David Prefontaine, PhD and Rahul Lad, PhD (Novartis), and Praveen Kaul, PhD for providing medical writing and editorial support, which was funded by Novartis Pharma AG in accordance with Good Publication Practice (GPP3) guidelines.Peer reviewedPublisher PD
Ryegrass Seeding Rate Alters Plant Morphology and Size--Possible Implications for Pasture Persistence
Poor persistence of perennial ryegrass (Lolium perenne L.) is a major dairy industry issue in New Zealand and Australia. New ryegrass seed is often drilled at 18-30 kg/ha, although previous research indicated that pastures drilled at 10-12 kg/ha can be just as productive (Frame and Boyd 1986; Praat et al. 1996). High seeding rates increase competition between developing seedlings for light, water and nutrients, reduce plant size (Harris 1990) and potentially survival.
The experiment reported here investigated the effect of plant density (created by differences in seeding rate) on plant morphology and survival. The hypothesis was that plants established from high seeding rates will be smaller and, therefore, less likely to survive the first summer; a period of substantial environmental stress (e.g., high temperatures, low soil moisture, insect attack)
The PAndAS Field of Streams: stellar structures in the Milky Way halo toward Andromeda and Triangulum
We reveal the highly structured nature of the Milky Way stellar halo within
the footprint of the PAndAS photometric survey from blue main sequence and main
sequence turn-off stars. We map no fewer than five stellar structures within a
heliocentric range of ~5 to 30 kpc. Some of these are known (the Monoceros
Ring, the Pisces/Triangulum globular cluster stream), but we also uncover three
well-defined stellar structures that could be, at least partly, responsible for
the so-called Triangulum/Andromeda and Triangulum/Andromeda 2 features. In
particular, we trace a new faint stellar stream located at a heliocentric
distance of ~17 kpc. With a surface brightness of \Sigma_V ~ 32-32.5
mag/arcsec^2, it follows an orbit that is almost parallel to the Galactic plane
north of M31 and has so far eluded surveys of the Milky Way halo as these tend
to steer away from regions dominated by the Galactic disk. Investigating our
follow-up spectroscopic observations of PAndAS, we serendipitously uncover a
radial velocity signature from stars that have colors and magnitudes compatible
with the stream. From the velocity of eight likely member stars, we show that
this stellar structure is dynamically cold, with an unresolved velocity
dispersion that is lower than 7.1 km/s at the 90-percent confidence level.
Along with the width of the stream (300-650 pc), its dynamics points to a
dwarf-galaxy-accretion origin. The numerous stellar structures we can map in
the Milky Way stellar halo between 5 and 30 kpc and their varying morphology is
a testament to the complex nature of the stellar halo at these intermediate
distances.Comment: 11 pages, 8 figures, accepted for publication in the ApJ, Figure 3 is
the money plo
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