1,664 research outputs found
CFVS: Coarse-to-Fine Visual Servoing for 6-DoF Object-Agnostic Peg-In-Hole Assembly
Robotic peg-in-hole assembly remains a challenging task due to its high
accuracy demand. Previous work tends to simplify the problem by restricting the
degree of freedom of the end-effector, or limiting the distance between the
target and the initial pose position, which prevents them from being deployed
in real-world manufacturing. Thus, we present a Coarse-to-Fine Visual Servoing
(CFVS) peg-in-hole method, achieving 6-DoF end-effector motion control based on
3D visual feedback. CFVS can handle arbitrary tilt angles and large initial
alignment errors through a fast pose estimation before refinement. Furthermore,
by introducing a confidence map to ignore the irrelevant contour of objects,
CFVS is robust against noise and can deal with various targets beyond training
data. Extensive experiments show CFVS outperforms state-of-the-art methods and
obtains 100%, 91%, and 82% average success rates in 3-DoF, 4-DoF, and 6-DoF
peg-in-hole, respectively
Kinetic model of disinfection using novel Chitosan-N-Doped TiO2 photocatalyst derived from fishery waste
Discovery of a New Member of the Inner Oort Cloud from The Next Generation Virgo Cluster Survey
We report the discovery of 2010 GB, a likely new member of the Inner
Oort Cloud (IOC). 2010 GB is one of 91 Trans Neptunian Objects (TNOs)
and Centaurs discovered in a 76 deg contiguous region imaged as part of the
Next Generation Virgo Cluster Survey (NGVS) --- a moderate ecliptic latitude
survey reaching a mean limiting magnitude of --- using
MegaPrime on the 3.6m Canada France Hawaii Telescope. 2010 GB is found
to have an orbit with semi-major axis AU, inclination and pericentre AU. This is the second largest
perihelion distance among known solar system objects. Based on the sky coverage
and depth of the NGVS, we estimate the number of IOC members with sizes larger
than 300 km ( mag) to be . A comparison of the
detection rate from the NGVS and the PDSSS (a characterized survey that
`re-discovered' the IOC object Sedna) gives, for an assumed a power-law LF for
IOC objects, a slope of , with only two detections
in this region this slope estimate is highly uncertain.Comment: 20 pages, 3 figures, 1 table. Accepted for publication in The
Astrophysical Journal Letter
Torsion of right middle lobe after a right upper lobectomy
Lobar torsion after lung resection is a quite rare complication. A 50-year-old woman presented typical features on chest radiographs and CT(computed tomography) scan of lobar torsion after a right upper lobectomy. After emergency lobectomy of right middle lobe, the patient recovered well and discharged 10 days after the second operation
Antioxidant Activities and Phytochemical Study of Leaf Extracts from 18 Indigenous Tree Species in Taiwan
The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species, Acer oliverianum exhibited the best free radical scavenging activities. The IC50 values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition, A. oliverianum also exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isolation principle, the resulting methanolic crude extracts of A. oliverianum leaves were fractionated to yield soluble fractions of hexane, EtOAc, BuOH, and water. Of these, the EtOAc fraction had the best antioxidant activity. Furthermore, 8 specific phytochemicals were isolated and identified from the EtOAc fraction. Among them, 1,2,3,4,6-O-penta-galloyl-β-D-glucopyranose had the best free radical scavenging activity. These results demonstrate that methanolic extracts and their derived phytochemicals of A. oliverianum leaves have excellent antioxidant activities and thus they have great potential as sources for natural health products
OSSOS VI. Striking Biases in the detection of large semimajor axis Trans-Neptunian Objects
The accumulating, but small, set of large semi-major axis trans-Neptunian
objects (TNOs) shows an apparent clustering in the orientations of their
orbits. This clustering must either be representative of the intrinsic
distribution of these TNOs, or else arise as a result of observation biases
and/or statistically expected variations for such a small set of detected
objects. The clustered TNOs were detected across different and independent
surveys, which has led to claims that the detections are therefore free of
observational bias. This apparent clustering has led to the so-called "Planet
9" hypothesis that a super-Earth currently resides in the distant solar system
and causes this clustering. The Outer Solar System Origins Survey (OSSOS) is a
large program that ran on the Canada-France-Hawaii Telescope from 2013--2017,
discovering more than 800 new TNOs. One of the primary design goals of OSSOS
was the careful determination of observational biases that would manifest
within the detected sample. We demonstrate the striking and non-intuitive
biases that exist for the detection of TNOs with large semi-major axes. The
eight large semi-major axis OSSOS detections are an independent dataset, of
comparable size to the conglomerate samples used in previous studies. We
conclude that the orbital distribution of the OSSOS sample is consistent with
being detected from a uniform underlying angular distribution.Comment: Accepted for publicatio
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