24 research outputs found
NegVSR: Augmenting Negatives for Generalized Noise Modeling in Real-World Video Super-Resolution
The capability of video super-resolution (VSR) to synthesize high-resolution
(HR) video from ideal datasets has been demonstrated in many works. However,
applying the VSR model to real-world video with unknown and complex degradation
remains a challenging task. First, existing degradation metrics in most VSR
methods are not able to effectively simulate real-world noise and blur. On the
contrary, simple combinations of classical degradation are used for real-world
noise modeling, which led to the VSR model often being violated by
out-of-distribution noise. Second, many SR models focus on noise simulation and
transfer. Nevertheless, the sampled noise is monotonous and limited. To address
the aforementioned problems, we propose a Negatives augmentation strategy for
generalized noise modeling in Video Super-Resolution (NegVSR) task.
Specifically, we first propose sequential noise generation toward real-world
data to extract practical noise sequences. Then, the degeneration domain is
widely expanded by negative augmentation to build up various yet challenging
real-world noise sets. We further propose the augmented negative guidance loss
to learn robust features among augmented negatives effectively. Extensive
experiments on real-world datasets (e.g., VideoLQ and FLIR) show that our
method outperforms state-of-the-art methods with clear margins, especially in
visual quality
Deep learning facilitates fully automated brain image registration of optoacoustic tomography and magnetic resonance imaging
Multispectral optoacoustic tomography (MSOT) is an emerging optical imaging method providing multiplex molecular and functional information from the rodent brain. It can be greatly augmented by magnetic resonance imaging (MRI) which offers excellent soft-tissue contrast and high-resolution brain anatomy. Nevertheless, registration of MSOT-MRI images remains challenging, chiefly due to the entirely different image contrast rendered by these two modalities. Previously reported registration algorithms mostly relied on manual user-dependent brain segmentation, which compromised data interpretation and quantification. Here we propose a fully automated registration method for MSOT-MRI multimodal imaging empowered by deep learning. The automated workflow includes neural network-based image segmentation to generate suitable masks, which are subsequently registered using an additional neural network. The performance of the algorithm is showcased with datasets acquired by cross-sectional MSOT and high-field MRI preclinical scanners. The automated registration method is further validated with manual and half-automated registration, demonstrating its robustness and accuracy
Crystal Structure of the Caenorhabditis elegans Apoptosome Reveals an Octameric Assembly of CED-4
SummaryThe CED-4 homo-oligomer or apoptosome is required for initiation of programmed cell death in Caenorhabditis elegans by facilitating autocatalytic activation of the CED-3 caspase zymogen. How the CED-4 apoptosome assembles and activates CED-3 remains enigmatic. Here we report the crystal structure of the complete CED-4 apoptosome and show that it consists of eight CED-4 molecules, organized as a tetramer of an asymmetric dimer via a previously unreported interface among AAA+ ATPases. These eight CED-4 molecules form a funnel-shaped structure. The mature CED-3 protease is monomeric in solution and forms an active holoenzyme with the CED-4 apoptosome, within which the protease activity of CED-3 is markedly stimulated. Unexpectedly, the octameric CED-4 apoptosome appears to bind only two, not eight, molecules of mature CED-3. The structure of the CED-4 apoptosome reveals shared principles for the NB-ARC family of AAA+ ATPases and suggests a mechanism for the activation of CED-3
Backstepping Sliding Mode Control for Radar Seeker Servo System Considering Guidance and Control System
This paper investigates the design of a missile seeker servo system combined with a guidance and control system. Firstly, a complete model containing a missile seeker servo system, missile guidance system, and missile control system (SGCS) was creatively proposed. Secondly, a designed high-order tracking differentiator (HTD) was used to estimate states of systems in real time, which guarantees the feasibility of the designed algorithm. To guarantee tracking precision and robustness, backstepping sliding-mode control was adopted. Aiming at the main problem of projectile motion disturbance, an adaptive radial basis function neural network (RBFNN) was proposed to compensate for disturbance. Adaptive RBFNN especially achieves online adjustment of residual error, which promotes estimation precision and eliminates the “chattering phenomenon”. The boundedness of all signals, including estimation error of high-order tracking differentiator, was especially proved via the Lyapunov stability theory, which is more rigorous. Finally, in considered scenarios, line of sight angle (LOSA)-tracking simulations were carried out to verify the tracking performance, and a Monte Carlo miss-distance simulation is presented to validate the effectiveness of the proposed method
Spatiotemporal Distribution and Risk Assessment of Heat Waves Based on Apparent Temperature in the One Belt and One Road Region
Heat waves seriously affect the productivity and daily life of human beings. Therefore, they bring great risks and uncertainties for the further development of countries in the One Belt and One Road (OBOR) region. In this study, we used daily meteorological monitoring data to calculate the daily apparent temperature and annual heat wave dataset for 1989–2018 in the OBOR region. Then, we studied their spatiotemporal distribution patterns. Additionally, multi-source data were used to assess heat wave risk in the OBOR region. The main results are as follows: (1) The daily apparent temperature dataset and annual heat wave dataset for 1989–2018 in the OBOR region at 0.1° × 0.1° gridded resolution were calculated. China, South Asia and Southeast Asia are suffering the most serious heat waves in the OBOR region, with an average of more than six heat waves, lasting for more than 60 days and the extreme apparent temperature has reached over 40 °C. Additionally, the frequency, duration and intensity of heat waves have been confirmed to increase continuously. (2) The heat wave risk in the OBOR region was assessed. Results show that the high heat wave risk areas are distributed in eastern China, northern South Asia and some cities. The main conclusion is that the heat wave risk in most areas along the OBOR route is relatively high. In the process of deepening the development of countries in the OBOR region, heat wave risk should be fully considered
Backstepping Sliding Mode Control for Radar Seeker Servo System Considering Guidance and Control System
This paper investigates the design of a missile seeker servo system combined with a guidance and control system. Firstly, a complete model containing a missile seeker servo system, missile guidance system, and missile control system (SGCS) was creatively proposed. Secondly, a designed high-order tracking differentiator (HTD) was used to estimate states of systems in real time, which guarantees the feasibility of the designed algorithm. To guarantee tracking precision and robustness, backstepping sliding-mode control was adopted. Aiming at the main problem of projectile motion disturbance, an adaptive radial basis function neural network (RBFNN) was proposed to compensate for disturbance. Adaptive RBFNN especially achieves online adjustment of residual error, which promotes estimation precision and eliminates the “chattering phenomenon”. The boundedness of all signals, including estimation error of high-order tracking differentiator, was especially proved via the Lyapunov stability theory, which is more rigorous. Finally, in considered scenarios, line of sight angle (LOSA)-tracking simulations were carried out to verify the tracking performance, and a Monte Carlo miss-distance simulation is presented to validate the effectiveness of the proposed method
Prescribed Performance Control for Two-axis Optronic Stabilized Platform
Aiming at improving the tracking and stabilizing performance of two-axis optronic stabilized platform with Stribeck friction and uncertain velocity disturbance, a prescribed performance control strategy with unknown initial errors is designed. By designing a new performance function, the limit of traditional prescribed control that the initial error has to be known accurately is broken through. The strategy possesses strong robustness against unknown disturbance, and the state error is restrained to a predefined arbitrary small residual. It is guaranteed that the closed-loop system is uniformly ultimately bounded. The simulation results demonstrate the effectiveness of proposed strategy
Progress Preservation Techniques Loquat Harvest
This paper describes the major physiological changes after the loquat harvest, and the most recent year delay on postharvest technologies and principles to reduce postharvest loquat fruit quality made elaborate
Preliminary Study on The Control Method of
From 2018 to 2019, the control methods of Prunus americanc fruit were tested with Prunus americanc as experimental material. The fruit cracking rate of fruit trees was reduced by using comprehensive technical measures such as orchard grass, plastic film mulching, spraying gibberellin and spraying calcium fertilizer. The results showed that all treatments could reduce the fruit cracking rate of American plum fruit, and the effect of spraying gibberellin was the best
Prescribed Performance Control for Two-axis Optronic Stabilized Platform
Aiming at improving the tracking and stabilizing performance of two-axis optronic stabilized platform with Stribeck friction and uncertain velocity disturbance, a prescribed performance control strategy with unknown initial errors is designed. By designing a new performance function, the limit of traditional prescribed control that the initial error has to be known accurately is broken through. The strategy possesses strong robustness against unknown disturbance, and the state error is restrained to a predefined arbitrary small residual. It is guaranteed that the closed-loop system is uniformly ultimately bounded. The simulation results demonstrate the effectiveness of proposed strategy