This article addresses the adaptive tracking control problem for switched uncertain nonlinear systems with state constraints via multiple Lyapunov function approach. The system functions are considered unknown and approximated by radial basis neural networks (RBFNNs). For constraint problem, barrier (BLFs) chosen to ensure satisfaction of constrained properties. Moreover, a state-dependent switching law is designed, which does not require stability individual subsystems. Then, using...

Abstract Underwater acoustic navigation is extensively utilized across many industries due to its exceptional dependability and continuous real-time functionality. Due the swift advancement of technology in recent years, velocity autonomous underwater vehicles (AUVs) has progressively increased. A high frame rate required for system order precisely obtain trajectory AUV. Nevertheless, discrepancy lies fact that unambiguous measurement could be seen as contradictory. Higher rates greatly...

Motivation: The emergence of single-cell RNA sequencing (scRNA-seq) technology has paved the way for measuring levels at resolution to study precise biological functions. However, presence a large number missing values in its data will affect downstream analysis. This paper presents AdImpute: an imputation method based on semi-supervised autoencoders. uses another (DrImpute is used as example) fill results weights autoencoder, and applies cost function with learn latent information achieve...

We investigate the tracking control problem for a non-strict feedback nonlinear system with external disturbance and time-varying asymmetric full state constraints. Firstly, unknown term in are estimated by fuzzy logic system. The backstepping method is applied to design of adaptive controller. However, prevent that constraints overstepped introducing an improved log-type barrier Lyapunov function (TABLF) each step design. Secondly, dynamic surface (DSC) introduced designed algorithm solve...

This paper concerns the control algorithm oriented to nonparallel-ground-track-imaging for agile optical satellite. Firstly, obtaining desired trajectory, mapping relationship between satellite attitude and ground stripe is established by using space vector method. According function, an adjustment strategy via constant scanning velocity proposed. Then, considering exact information of external disturbance cannot be obtained input saturation problem, a robust anti-saturation tracking...

Abstract Uniform linear array (ULA) is commonly used for collecting underwater acoustic signals, and the direction-of-arrival (DOA) obtained by signal processing methods. The ULA-based multi-source DOA tracking suffers from performance degradation caused presence of false tracks port-starboard ambiguity. To address this problem, we propose a bearing ambiguity discrimination algorithm. Firstly, sum real motion velocity between truth ambiguous targets established with Gaussian distribution....

The dynamics of valve train is influenced by stiffness, size, and mass distribution its components initial clearance so on. All the factors should be taken into consideration correctly dynamic model described qualitatively quantitatively through mathematical variables. This paper proposes a new simplified method for components, namely, mode matching (MMM) camshaft, pushrod, rocker arm, valve, spring. In this method, amount lumped masses each flexible component determined based on natural...

The engine vibration and noise induced by a valve train element are analyzed through the modeling experiment method. dynamics first studied to make clear sources of noise. component flexibility inertia mass all taken into consideration as well contact or impact behaviors. forces applied on combined model structure. resulting responses at outer surfaces considered be boundary conditions acoustic model. is built analysis results show that mainly in 500–800 Hz 1/3 octave bands. this frequency...

Aiming at a long-term formation-keeping problem for the satellite swarm, concept of loosely displaced formation is proposed in this article. On basis, continuous low-thrust control strategy maintaining designed. The objective to reduce more fuel consumption during formation-keeping. For achieving that, we forward-feedback by using pseudo-spectral method and sliding mode theory. To be specific, includes two parts: forward feedback control. control, numerical optimization with Legendre...

This study proposes a nonsingular fast terminal sliding mode control strategy based on an adaptive finite time disturbance observer for trajectory tracking of uncertain rigid manipulators with external disturbances. Firstly, (AFTSMDO) is designed to suppress and compensate the total caused by uncertainty manipulator model interference. The introduced law can estimate centralized perturbation in real time, parameters are set independent specific value Secondly, new non-singular surface...

Absorbing boundary conditions (ABCs) play a critical role in the simulation of sound or wave propagation problems. This paper proposes technique space-time transformed perfectly matched layer (PML) condition implemented widely used mesh-free method called smoothed particle hydrodynamic (SPH) method, to absorb outgoing waves with oblique shear mean flow. Special consideration is given features SPH, and PMLs are formulated correct truncation error SPH at same time, aiming reduce storage...

Abstract With the deepening of related research, relevant theories signal processing and final acquisition method have made significant achievements, which been widely applied to image processing, radar other fields, promoting continuous improvement technology. A series facts show that progress can effectively promote development disciplines. The combination ADCP data technology is relatively late, but now it has become an important information continues develop towards systematization...