DPFNet: A Dual-branch Dilated Network with Phase-aware Fourier Convolution for Low-light Image Enhancement

Low-light image enhancement is a classical computer vision problem aiming to recover normal-exposure images from low-light images. However, convolutional neural networks commonly used in this field are good at sampling low-frequency local structural features in the spatial domain, which leads to unclear texture details of the reconstructed images. To alleviate this problem, we propose a novel module using the Fourier coefficients, which can recover high-quality texture details under the constraint of semantics in the frequency phase and supplement the spatial domain. In addition, we design a simple and efficient module for the image spatial domain using dilated convolutions with different receptive fields to alleviate the loss of detail caused by frequent downsampling. We integrate the above parts into an end-to-end dual branch network and design a novel loss committee and an adaptive fusion module to guide the network to flexibly combine spatial and frequency domain features to generate more pleasing visual effects. Finally, we evaluate the proposed network on public benchmarks. Extensive experimental results show that our method outperforms many existing state-of-the-art ones, showing outstanding performance and potential

Role of CaMKII and PKA in early afterdepolarization of human ventricular myocardium cell: A Computational model study

Early afterdepolarization (EAD) plays an important role in arrhythmogenesis. Many experimental studies have reported that Ca2+/calmodulin-dependent protein kinase II (CaMKII) and β-adrenergic signaling pathway are two important regulators. In this study, we developed a modified computational model of human ventricular myocyte to investigate the combined role of CaMKII and β-adrenergic signaling pathway on the occurrence of EADs. Our simulation results showed that () CaMKII overexpression facilitates EADs through the prolongation of late sodium current’s () deactivation progress; () the combined effect of CaMKII overexpression and activation of β-adrenergic signaling pathway further increases the risk of EADs, where EADs could occur at shorter cycle length (2000 ms versus 4000 ms) and lower rapid delayed rectifier K+ current () blockage (77% versus 85%). In summary, this study computationally demonstrated the combined role of CaMKII and β-adrenergic signaling pathway on the occurrence of EADs, which could be useful for searching for therapy strategies to treat EADs related arrhythmogenesis

Experiments on bright field and dark field high energy electron imaging with thick target material

Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Here we report on an electron radiography experiment using 45 MeV electrons from an S-band photo-injector, where scattered electrons, after interacting with a sample, are collected and imaged by a quadrupole imaging system. We achieved a few micrometers (about 4 micrometers) spatial resolution and about 10 micrometers thickness resolution for a silicon target of 300-600 micron thickness. With addition of dark field images that are captured by selecting electrons with large scattering angle, we show that more useful information in determining external details such as outlines, boundaries and defects can be obtained.Comment: 7pages, 7 figure

Optical Fiber LSPR Biosensor Prepared by Gold Nanoparticle Assembly on Polyelectrolyte Multilayer

This article provides a novel method of constructing an optical fiber localized surface plasmon resonance (LSPR) biosensor. A gold nanoparticle (NP) assembled film as the sensing layer was built on the polyelectrolyte (PE) multilayer modified sidewall of an unclad optical fiber. By using a trilayer PE structure, we obtained a monodisperse gold NP assembled film. The preparation procedure for this LSPR sensor is simple and time saving. The optical fiber LSPR sensor has higher sensitivity and outstanding reproducibility. The higher anti-interference ability for response to an antibody makes it a promising method in application as a portable immuno-sensor

Finite-horizon H∞ control for a class of time-varying nonlinear systems subject to sensor and actuator saturations

In this paper, a time-varying dynamic output feedback controller is designed, which aims to solve the finite-horizon H∞ control problem for a class of discrete-time time-varying nonlinear systems subject to actuator and sensor saturations. The nonlinearities of the system under consideration satisfy the sector conditions, which include the Lipschitz non-linearities as a special case. To effectively handle the saturation nonlinearities, a compact convex hull representation is utilized, which leads to less conservative conditions for the controller design than the existing results due to imposition of extra slack variables. The sufficient conditions derived are expressed in the form of a series of recursive linear matrix inequalities. By outlining an implementation algorithm, the finite-horizon H∞ controller can be designed online. Finally, a numerical example is presented to demonstrate the feasibility and efficacy of the proposed method

An efficient method for control of continuous-time systems subject to input saturation and external disturbance

In this paper the problem of control of continuous-time systems subject to input saturation and external disturbance is studied. The key idea is to construct a disturbance observer to enable the design of an efficient anti-disturbance controller. The new disturbance observer based controller can ensure asymptotical stability of the resulting closed-loop system. Moreover, an estimation of the domain of attraction is provided, and it can also be maximized by using an iterative algorithm. The theoretical findings are validated by a numerical example

Design of anti-windup gains for Markovian jump systems subject to parametric uncertainty and actuator saturation

The problem of design of anti-windup gains for Markovian jump systems subject to parametric uncertainty and actuator saturation is addressed in this paper. The system under study is assumed to have partially unknown transition rates. A set of anti-windup compensation gains are designed for dynamic output feedback controllers that have been designed in advance for stabilization in the absence of control saturation. It is shown that the redesigned controllers can achieve stabilization of the system regardless the presence or absence of actuator saturation. A convex optimization method is developed to obtain the largest possible estimation of the domain of attraction for the closed-loop system. Simulation results are presented to illustrate the effectiveness of the proposed method

Design of robust observer-based controller for uncertain time-delay systems with saturating actuators

This paper is concerned with designing robust observer-based controller for continuous-time time-delay systems with saturating actuators and subject to time-varying uncertainties. With the assumption that the system states are not available but detectable, the observer-based output feedback controller is designed under some delay-dependent conditions derived, and the controller thus designed guarantees that the system without perturbations on its input matrices can be stabilized together with the domain of attraction. In addition, an iterative optimization algorithm is developed to acquire a maximal estimate of the domain of attraction. Moreover, in the presence of perturbations on the system input matrices, the gain of the observer given by the above-mentioned controller design rules is adjusted in terms of some stabilization conditions derived. The theoretical findings are finally verified by an illustrative example along with computer simulations