175,415 research outputs found
AI for public health: Self-screening for eye diseases
A software-based visual-field testing (perimetry) system is described which incorporates several AI components, including machine learning, an intelligent user interface and pattern discovery. This system has been successfully used for self-screening in several different public environment
A search algorithm for a class of optimal finite-precision controller realization problems with saddle points
With game theory, we review the optimal digital controller realization problems that maximize a finite word length (FWL) closed-loop stability measure. For a large class of these optimal FWL controller realization problems which have saddle points, a minimax-based search algorithm is derived for finding a global optimal solution. The algorithm consists of two stages. In the first stage, the closed form of a transformation set is constructed which contains global optimal solutions. In the second stage, a subgradient approach searches this transformation set to obtain a global optimal solution. This algorithm does not suffer from the usual drawbacks associated with using direct numerical optimization methods to tackle these FWL realization problems. Furthermore, for a small class of optimal FWL controller realization problems which have no saddle point, the proposed algorithm also provides useful information to help solve them
A multi-dimensional SRBM: Geometric views of its product form stationary distribution
We present a geometric interpretation of a product form stationary
distribution for a -dimensional semimartingale reflecting Brownian motion
(SRBM) that lives in the nonnegative orthant. The -dimensional SRBM data can
be equivalently specified by geometric objects: an ellipse and rays.
Using these geometric objects, we establish necessary and sufficient conditions
for characterizing product form stationary distribution. The key idea in the
characterization is that we decompose the -dimensional problem to
two-dimensional SRBMs, each of which is determined by an
ellipse and two rays. This characterization contrasts with the algebraic
condition of [14]. A -station tandem queue example is presented to
illustrate how the product form can be obtained using our characterization.
Drawing the two-dimensional results in [1,7], we discuss potential optimal
paths for a variational problem associated with the three-station tandem queue.
Except Appendix D, the rest of this paper is almost identical to the QUESTA
paper with the same title
Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K)
The specific heat of BaFeAs single crystal, electron-doped
BaLaFeAs and hole-doped BaKFeAs
polycrystals were measured. For undoped BaFeAs single crystal, a very
sharp specific heat peak was observed at 136 K. This is attributed to the
structural and antiferromagnetic transitions occurring at the same temperature.
of the electron-doped non-superconducting
BaLaFeAs also shows a small peak at 120 K, indicating a
similar but weaker structural/antiferromagnetic transition. For the hole-doped
superconducting BaKFeAs, a clear peak of was
observed at = 36 K, which is the highest peak seen at superconducting
transition for iron-based high- superconductors so far. The electronic
specific heat coefficient and Debye temperature of these
compounds were obtained from the low temperature data
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