19,622 research outputs found
Magnetic attachment mechanism
A magnetic attachment mechanism adapted for interfacing with the manipulator arm of a remote manipulator system and comprising a pair of permanent magnets of rare earth material are arranged in a stator-rotor relationship. The rotor magnet is journalled for rotation about its longitudinal axis between pole plates of the stator magnet, each of which includes an adhering surface. In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet is closely adjacent to a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces for attracting a ferrous magnetic plate, or the like, affixed to the payload. When the rotor magnet is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet is disposed closely adjacent to a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces, which permits the release of a payload. An actuator for selectively rotating the rotor magnet between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For affecting an optimal rigidized attachment the payload is provided with guide means cooperable with guide means on the housing of the mechanism for directing adhering surfaces of the polar plates to the ferrous plate
Privacy-Preserving Shortest Path Computation
Navigation is one of the most popular cloud computing services. But in
virtually all cloud-based navigation systems, the client must reveal her
location and destination to the cloud service provider in order to learn the
fastest route. In this work, we present a cryptographic protocol for navigation
on city streets that provides privacy for both the client's location and the
service provider's routing data. Our key ingredient is a novel method for
compressing the next-hop routing matrices in networks such as city street maps.
Applying our compression method to the map of Los Angeles, for example, we
achieve over tenfold reduction in the representation size. In conjunction with
other cryptographic techniques, this compressed representation results in an
efficient protocol suitable for fully-private real-time navigation on city
streets. We demonstrate the practicality of our protocol by benchmarking it on
real street map data for major cities such as San Francisco and Washington,
D.C.Comment: Extended version of NDSS 2016 pape
THE ENVIRONMENTAL EFFECTS OF FREEDOM TO FARM
The Federal Agriculture Improvement and Reform Act (FAIR) of 1996 ended commodity specific subsidies and resulted in a significant shift in corn and soybean production in 1997. While conservation compliance improved the environmental health of the Central U.S., changes in production due to the FAIR act have tempered these improvements.Agricultural and Food Policy, Environmental Economics and Policy,
SIMPEL: Circuit model for photonic spike processing laser neurons
We propose an equivalent circuit model for photonic spike processing laser
neurons with an embedded saturable absorber---a simulation model for photonic
excitable lasers (SIMPEL). We show that by mapping the laser neuron rate
equations into a circuit model, SPICE analysis can be used as an efficient and
accurate engine for numerical calculations, capable of generalization to a
variety of different laser neuron types found in literature. The development of
this model parallels the Hodgkin--Huxley model of neuron biophysics, a circuit
framework which brought efficiency, modularity, and generalizability to the
study of neural dynamics. We employ the model to study various
signal-processing effects such as excitability with excitatory and inhibitory
pulses, binary all-or-nothing response, and bistable dynamics.Comment: 16 pages, 7 figure
Design and experimental demonstration of optomechanical paddle nanocavities
We present the design, fabrication and initial characterization of a paddle
nanocavity consisting of a suspended sub-picogram nanomechanical resonator
optomechanically coupled to a photonic crystal nanocavity. The optical and
mechanical properties of the paddle nanocavity can be systematically designed
and optimized, and key characteristics including mechanical frequency easily
tailored. Measurements under ambient conditions of a silicon paddle nanocavity
demonstrate an optical mode with quality factor ~ 6000 near 1550 nm, and
optomechanical coupling to several mechanical resonances with frequencies
~ 12-64 MHz, effective masses ~ 350-650 fg, and
mechanical quality factors ~ 44-327. Paddle nanocavities are promising
for optomechanical sensing and nonlinear optomechanics experiments.Comment: 5 pages, 4 figure
Magnetic attachment mechanism
A magnetic attachment mechanism adapted for interfacing with the manipulator arm (11) of a remote manipulator system and comprising a pair of permanent magnets (31,32) of rare earth material which are arranged in a stator-rotor relationship. The rotor magnet (32), is journalled for rotation about its longitudinal axis between pole plates (35,36) of the stator magnet (31), each of which includes an adhering surface (35a,36a). In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet (32) is closely adjacent a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces (35a,36a) for attracting a ferrous magnetic plate 20, or the like, affixed to the payload (20 or 50). When the rotor magnet (32) is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet (31) is disposed closely adjacent a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces (35a,36a) which permits the release of a payload. An actuator (51 or 70) for selectively rotating the rotor magnet (32) between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For effecting an optimal rigidized attachment the payload is provided with guides (91,92) cooperable with guides (96,16,17) on the housing of the mechanism for directing adhering surfaces (35a,36a) of the polar plates to the ferrous plate (20)
Being Sherlock Holmes: Can we sense empathy from a brief sample of behaviour?
Mentalizing (otherwise known as ‘theory of mind’) involves a special process that is adapted for predicting and explaining the behaviour of others (targets) based on inferences about targets’ beliefs and character. This research investigated how well participants made inferences about an especially apposite aspect of character, empathy. Participants were invited to make inferences of self-rated empathy after watching or listening to an unfamiliar target for a few seconds telling a scripted joke (or answering questions about him/herself or reading aloud a paragraph of promotional material). Across three studies, participants were good at identifying targets with low and high self-rated empathy but not good at identifying those who are average. Such inferences, especially of high self-rated empathy, seemed to be based mainly on clues in the target's behaviour, presented either in a video, a still photograph or in an audio track. However, participants were not as effective in guessing which targets had low or average self-rated empathy from a still photograph showing a neutral pose or from an audio track. We conclude with discussion of the scope and the adaptive value of this inferential ability
System configuration, fault detection, location, isolation and restoration: a review on LVDC Microgrid protections
Low voltage direct current (LVDC) distribution has gained the significant interest of research due to the advancements in power conversion technologies. However, the use of converters has given rise to several technical issues regarding their protections and controls of such devices under faulty conditions. Post-fault behaviour of converter-fed LVDC system involves both active converter control and passive circuit transient of similar time scale, which makes the protection for LVDC distribution significantly different and more challenging than low voltage AC. These protection and operational issues have handicapped the practical applications of DC distribution. This paper presents state-of-the-art protection schemes developed for DC Microgrids. With a close look at practical limitations such as the dependency on modelling accuracy, requirement on communications and so forth, a comprehensive evaluation is carried out on those system approaches in terms of system configurations, fault detection, location, isolation and restoration
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