26 research outputs found
Time-varying effect in the competing risks based on restricted mean time lost
Patients with breast cancer tend to die from other diseases, so for studies
that focus on breast cancer, a competing risks model is more appropriate.
Considering subdistribution hazard ratio, which is used often, limited to model
assumptions and clinical interpretation, we aimed to quantify the effects of
prognostic factors by an absolute indicator, the difference in restricted mean
time lost (RMTL), which is more intuitive. Additionally, prognostic factors may
have dynamic effects (time-varying effects) in long-term follow-up. However,
existing competing risks regression models only provide a static view of
covariate effects, leading to a distorted assessment of the prognostic factor.
To address this issue, we proposed a dynamic effect RMTL regression that can
explore the between-group cumulative difference in mean life lost over a period
of time and obtain the real-time effect by the speed of accumulation, as well
as personalized predictions on a time scale. Through Monte Carlo simulation, we
validated the dynamic effects estimated by the proposed regression having low
bias and a coverage rate of around 95%. Applying this model to an elderly
early-stage breast cancer cohort, we found that most factors had different
patterns of dynamic effects, revealing meaningful physiological mechanisms
underlying diseases. Moreover, from the perspective of prediction, the mean
C-index in external validation reached 0.78. Dynamic effect RMTL regression can
analyze both dynamic cumulative effects and real-time effects of covariates,
providing a more comprehensive prognosis and better prediction when competing
risks exist
Recommended from our members
Deterministic stabilization of eight-way 2D diffractive beam combining using pattern recognition.
We demonstrate a new method for controlling diffractive, high-power beam combination, sensing phase errors by analyzing the intensity pattern of uncombined side beams at the output. A square array of eight beams is combined with <0.3% stability and 84.6% efficiency. As the channel count is increased, so does the usable information, enabling scaling to large channel counts without significant slowing of control loop response time, an advantage over single-input algorithms
Recommended from our members
Stabilization of the 81-channel coherent beam combination using machine learning.
We develop a rapidly converging algorithm for stabilizing a large channel-count diffractive optical coherent beam combination. An 81-beam combiner is controlled by a novel, machine-learning based, iterative method to correct the optical phases, operating on an experimentally calibrated numerical model. A neural-network is trained to detect phase errors based on interference pattern recognition of uncombined beams adjacent to the combined one. Due to the non-uniqueness of solutions in the full space of possible phases, the network is trained within a limited phase perturbation/error range. This also reduces the number of samples needed for training. Simulations have proven that the network can converge in one step for small phase perturbations. When the trained neural-network is applied to a realistic case of 360 degree full range, an iterative scheme exploits random walking at the beginning, with the accuracy of prediction on phase feedback direction, to allow the neural-network to step into the training range for fast convergence. This neural-network-based iterative method of phase detection works tens of times faster than the commonly used stochastic parallel gradient descent approach (SPGD) using a single-detector and random dither when both are tested with random phase perturbations
Recommended from our members
81-beam coherent combination using a programmable array generator.
We have generated 81 independently controllable beams using a spatial light modulator and combined them on a diffractive combiner, to characterize the combiner and develop a fast phase error detection scheme. A key parameter of the diffractive combiner is measured in a new way, enabling an efficient combination when programming calibrated phases of each beam. This testbed provides a platform for development of advanced feedback phase control of high channel-count beam combination
Recommended from our members
81-beam coherent combination using a programmable array generator.
We have generated 81 independently controllable beams using a spatial light modulator and combined them on a diffractive combiner, to characterize the combiner and develop a fast phase error detection scheme. A key parameter of the diffractive combiner is measured in a new way, enabling an efficient combination when programming calibrated phases of each beam. This testbed provides a platform for development of advanced feedback phase control of high channel-count beam combination
Design of Intelligent Sorting Trash Dustbin Based on STM32
—Garbage sorting is related to many issues such as living environment, resource conservation and social civilization. Aiming at the problem of garbage sorting, an intelligent sorting trash dustbin was designed on the mechanical structure designed by ourselves, using the STM32F103ZET6 chip, the LD3320 speech recognition module, and the ultrasonic module. The garbage dustbin realizes the identification of garbage types, the compressed storage of recyclable garbage, and automatic bag sealing. This design not only protects the environment, reduces the risk of disease, but also makes resources recyclable, which indirectly brings unexpected benefits to humans
Recommended from our members
Stabilization of the 81-channel coherent beam combination using machine learning.
We develop a rapidly converging algorithm for stabilizing a large channel-count diffractive optical coherent beam combination. An 81-beam combiner is controlled by a novel, machine-learning based, iterative method to correct the optical phases, operating on an experimentally calibrated numerical model. A neural-network is trained to detect phase errors based on interference pattern recognition of uncombined beams adjacent to the combined one. Due to the non-uniqueness of solutions in the full space of possible phases, the network is trained within a limited phase perturbation/error range. This also reduces the number of samples needed for training. Simulations have proven that the network can converge in one step for small phase perturbations. When the trained neural-network is applied to a realistic case of 360 degree full range, an iterative scheme exploits random walking at the beginning, with the accuracy of prediction on phase feedback direction, to allow the neural-network to step into the training range for fast convergence. This neural-network-based iterative method of phase detection works tens of times faster than the commonly used stochastic parallel gradient descent approach (SPGD) using a single-detector and random dither when both are tested with random phase perturbations
Deterministic stabilization of eight-way 2D diffractive beam combining using pattern recognition
Recommended from our members
Experimental beam combining stabilization using machine learning trained while phases drift.
An 8-beam, diffractive coherent beam combiner is phase controlled by a learning algorithm trained while optical phases drift, using a differential mapping technique. Combined output power is stable to 0.4% with 95% of theoretical maximum efficiency, limited by the diffractive element
Recommended from our members
Deterministic stabilization of eight-way 2D diffractive beam combining using pattern recognition.
We demonstrate a new method for controlling diffractive, high-power beam combination, sensing phase errors by analyzing the intensity pattern of uncombined side beams at the output. A square array of eight beams is combined with <0.3% stability and 84.6% efficiency. As the channel count is increased, so does the usable information, enabling scaling to large channel counts without significant slowing of control loop response time, an advantage over single-input algorithms