6,548 research outputs found
Meta-analysis of death and myocardial infarction in the DEFINE-FLAIR and iFR-SWEDEHEART trials: a hypothesis generating note of caution
In patients with coronary heart disease, revascularization can improve symptoms and in certain high-risk subgroups may improve prognosis. Coronary angiography provides anatomical information and the physiological significance of a stenosis can be determined using fractional flow reserve (FFR). Decisions on the need for and mode of revascularization can be optimized using FFR, however this involves administering adenosine to induce hyperemia. Generally, this test is well tolerated, but in some healthcare systems adenosine is either not licensed, unavailable, or expensive, limiting the use of FFR-guided management
From a Patent Market for Lemons to a Marketplace for Patents: Benchmarking IP in Its Evolution to Asset Class Status
The Binary Nature of the Subgiant CH Stars
Repeated radial velocities have been measured for a sample of 10 subgiant CH
(sgCH) stars over a period of about 15 years. Long-term velocity variations are
exhibited by all but one star, and spectroscopic orbits have been calculated
for six of them. The periods are long, ranging from 876 to 4144 days. The
distribution of eccentricities and mass functions for sgCH star orbits are
similar to those for giant barium and CH stars, exhibiting significant orbital
dissipation relative to normal late-type binaries. It is concluded that all
sgCH stars are binaries, and like the barium and CH stars, they have had mass
transferred from a former asymptotic giant-branch star.Comment: 10 Latex pages, including 2 figures. Accepted by PASP. Also available
at http://www.hia.nrc.ca/eprints.htm
Resolving depth measurement ambiguity with commercially available range imaging cameras
Time-of-flight range imaging is typically performed with the amplitude modulated continuous wave method. This involves illuminating a scene with amplitude modulated light. Reflected light from the scene is received by the sensor with the range to the scene encoded as a phase delay of the modulation envelope. Due to the cyclic nature of phase, an ambiguity in the measured range occurs every half wavelength in distance, thereby limiting the maximum useable range of the camera.
This paper proposes a procedure to resolve depth ambiguity using software post processing. First, the range data is processed to segment the scene into separate objects. The average intensity of each object can then be used to determine which pixels are beyond the non-ambiguous range. The results demonstrate that depth ambiguity can be resolved for various scenes using only the available depth and intensity information. This proposed method reduces the sensitivity to objects with very high and very low reflectance, normally a key problem with basic threshold approaches.
This approach is very flexible as it can be used with any range imaging camera. Furthermore, capture time is not extended, keeping the artifacts caused by moving objects at a minimum. This makes it suitable for applications such as robot vision where the camera may be moving during captures.
The key limitation of the method is its inability to distinguish between two overlapping objects that are separated by a distance of exactly one non-ambiguous range. Overall the reliability of this method is higher than the basic threshold approach, but not as high as the multiple frequency method of resolving ambiguity
The Joint Venture and Related Contract Laws of Mainland China and Taiwan: a Comparative Analysis
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