Results 71 to 80 of about 993,247 (318)
Sensors, 2018 Finding a target quickly is one of the most important tasks in drone operations. In particular, rapid target detection is a critical issue for tasks such as finding rescue victims during the golden period, environmental monitoring, locating military ...
Il-Kyu Ha, You-Ze Cho
doaj +1 more source
A low sidelobe asymmetric beam antenna for high altitude platform communications [PDF]
, 2004 In a communications network served by a high altitude platform, the antenna beams illuminating each cell require minimized sidelobe powers. Asymmetric beams are advantageous so that cell footprints remain circular.
Thornton, J.
core +1 more source
Advanced Science, EarlyView.Ovarian macrophage depletion reverses OHSS resistance in estrildid finches and exacerbates OHSS symptoms in rats. Activating macrophage GPR183 alleviates OHSS by reducing pro‐inflammatory factors, increasing immunomodulatory molecules, remodeling CD44/SDC4‐mediated communication, and restoring immune homeostasis.
Xiaofei Yan +11 more
wiley +1 more source
Semi-analytical guidance algorithm for autonomous close approach to non-cooperative low-gravity targets [PDF]
, 2014 An adaptive guidance algorithm for close approach to and precision landing on uncooperative low-gravity objects (e.g. asteroids) is proposed. The trajectory, updated by means of a minimum fuel optimal control problem solving, is expressed in a polynomial
Armellin, Roberto +2 more
core
Metasurface‐Enabled Active‐Like Passive Radar
Advanced Science, EarlyView.A programmable space‐time‐coding metasurface embeds distinct spatiotemporal tags into ambient wireless signals, allowing passive radar to operate in an active‐like manner. By enabling code‐correlated reconstruction under interference, the approach supports robust real‐time UAV tracking in complex environments and points to intelligent, low‐power ...
Mingyi Li +7 more
wiley +1 more source
Low-altitude small target detection in sea clutter background based on improved CEEMDAN-IZOA-ELM
HeliyonTo effectively detect low-altitude small targets under complex sea surface environment, an innovative method has been developed. This method harnesses the chaotic characteristics of sea clutter and employs a combination of Adaptive Noise Complete ...
S. Shang +4 more
semanticscholar +1 more source
Ascent trajectory optimisation for a single-stage-to-orbit vehicle with hybrid propulsion [PDF]
, 2012 This paper addresses the design of ascent trajectories for a hybrid-engine, high performance, unmanned, single-stage-to-orbit vehicle for payload deployment into low Earth orbit. A hybrid optimisation technique that couples a population-based, stochastic
Brown, Richard +4 more
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Applied Economic Perspectives and Policy, EarlyView.ABSTRACT Rice is the main staple food for more than half of the world's population and the income from rice is an essential source for livelihoods of millions of households. We examine whether direct seed in rice production is an adaptation of rice farmers to rainfall changes and farm labor scarcity.
Manh Hung Do
wiley +1 more source
LEO space debris mitigation using laser ablation [PDF]
, 2014 Since the first spacecraft was launched in 1957 a great number of spacecraft have been put into orbit and a significant fraction of these are still orbiting the Earth as inert vehicles or space debris.
Birch, Philip +3 more
core
The Bitter Taste of Brazil's Temporary Import Ban on Robusta Coffee
Agribusiness, EarlyView.ABSTRACT Brazil, a leading Robusta coffee producer and exporter, faced a significant drought in 2016–2017, which drastically reduced production and depleted stocks. Consequently, Brazil temporarily permitted the import of one million 60‐kg bags of Robusta coffee in the spring 2017. An import ban was imposed shortly afterward due to lobbying by domestic
Hanifi Otgun +2 more
wiley +1 more source