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Sound wave is the only medium that can propagate effectively over long distances in the ocean. Underwater acoustic data plays an important role in the study of computational ocean acoustics. But the computation in three-dimensional underwater acoustic propagation is time-consuming, which is difficult to meet the real-time demand. In this paper, we put forward parallelization and performance optimization...
Magnetic resonance wireless power transfer (WPT) in the marine environment can be employed in the charging system for underwater vehicles. Seawater submersion of a WPT system results in additional energy loss through eddy current generation. In this paper, by equating the input power to the summation of power delivered to the load, consumed by transmitter and receiver coil resistances, and consumed...
The rain-fed agriculture dominates the agricultural production in Northeast China, which leads to the drought risk for crops growing. To assess the yields and necessity of irrigation for maize in the Three Northeast Provinces of China, the calibrated and validated WOrld FOod STudies (WOFOST) model was used to estimate maize yieldss in the regional scale after it was optimized by assimilating leaf...
The article introduces an actinomorphic soft robot that possesses a flattened body with a number of arms radially symmetric distributing and extending from robot central disc. Hence, mimicking radially symmetric musculature animals like starfish. The robot arm system, consisted of arm and smart material alloy (SMA) springs is the support structure as well as the robot propulsion device. A novel approach...
Playing a vital role, saliency has been widely applied for various image analysis tasks, such as content-aware image retargeting, image retrieval and object detection. It is generally accepted that saliency detection can benefit from the integration of multiple visual features. However, most of the existing literatures fuse multiple features at saliency map level without considering cross-feature...
This paper proposed a control strategy of differential steering specialized for four wheel independent driving (4WID) EVs. Different from traditional single torque-based control method, this strategy is designed to use the advantage of fast speed control of in-wheel motor. Four wheels are regulated to desired differential speed based on the reference vehicle velocity. Combined with Ackermann-Jeantand...
The increasing prospect of electric drive vehicles has led many different control schemes to apply on the driving system. Differential speed steering which do not use traditional steering mechanism is studied on a four-wheel-driving vehicle. By comparison with the traditional Ackerman-steered vehicle, differential-steered method shown its advantage on the simple structure. However, since the steering...
Torque is one of the most important control factors for a vehicle's motion. Compared with internal combustion engine, electric motors can have a more accurate torque feedback. In electric vehicles, direct torque control of the permanent magnet synchronous motor has been studied. However, because of non-ideal back EMF phenomenon, direct torque control of brushless DC motors has not been widely used...
This paper describes a greatly simplified model for the prediction of phase noise in oscillators which use a negative resistance as the active element. It is based on a simple circuit consisting of the parallel addition of a noise current, a negative admittance/resistance, and a parallel (Qlimited) resonant circuit. The transfer function is calculated as a forward trans-resistance (VOUT/IIN) and then...
Travelling wave fault location is the most common method for HVDC transmission line fault locating, the accuracy of which is of great importance for the fast recovery of HVDC transmission line faults. However, the accuracy further improvement is seriously obstructed by the coordination problem of the wavefront and the wave speed applied in existing fault location devices. To solve the problem, a novel...
Vegetation fractional cover which defines the amount of vegetation on the surface of the land, is a key parameter in land surface models. Based on a geometric-optical model in combination with linear spectral mixture analysis, this paper discusses the estimation of shrub fractional cover in Wushen Banner of Inner Mongolia in the Mu Us Sandland using HJ-1B image. Firstly, we acquire the surface reflectance...
This paper presents an in-depth modeling of a pressure-compensated flow control valve (PC valve) by making its physical meaning more understandable and analysable. Proper simplification is used to describe the internal principles of control laws. Theoretical analysis of the relation between the design parameter and the performance based on the valve model is described. The result of this method is...
In this paper an extended Kalman filter for real-time estimation of micro flight vehicle body attitude by using MEMS gyros, accelerometers, and magnetometers is presented. The algorithm uses quaternions to represent rotation, which can avoid the singularity problem caused by using Euler angles. Attitude quaternion errors and drift bias of gyros were selected to construct a state vector. The state...
The main goal of this paper is to analyze the flutter boundary and dynamic load of a supersonic fin. Reduced order mode (ROM) based on Volterra Series is presented to calculate the flutter boundary, and CFD/CSD coupling is used to compute the transient aerodynamic load. The Volterra-based ROM is obtained using the derivative of unsteady aerodynamic step-response, and the infinite plate spline is used...
A new nonlinear variable structure guidance law considering missile dynamics of autopilot against the space maneuver target is presented. Considering the target maneuverability as a disturbance with boundary, this guidance law constructs the switching surface by adding a nonlinear function which is confirmed by feedback optimization theory at the linear switching surface based on the proportional...
In this paper, radio frequency (RF) through-silicon via (TSV) designs and models are proposed to achieve high-frequency vertical connectivity for three dimensional (3D) multi-core and heterogeneous ICs. Specifically, coaxial dielectric and novel air-gap-based TSVs are designed and simulated to reduce signal degradation during RF operations. The simulation results demonstrate that these RF TSVs can...
Nonlinear aeroelasticity, caused by the interaction between transonic nonlinear fluid and geometrically nonlinear structure, is studied by coupling solution of the two fields. A predictor-corrector procedure with an approximately energy conservation is developed to obtain nonlinear structure response. Finite volume method with dual-time implicit technology is utilized to solve Reynolds averaged Navier-Stokes...
Space rendezvous is the foundation of space operation and application. In this paper, mission planning of long distance guidance stage for space rendezvous is discussed. Two-impulse rendezvous is solved by analyzing Gauss problem. Based on Battin-Vaughan algorithm, ergodic calculation is performed for different combination of initial position and transfer time. To carry out the mission planning for...
Computational structural dynamics (CSD) and Computational fluid dynamics (CFD) referring to aeroelasticity are highly nonlinear problems in time domain. Euler equation is solved by finite volume method with dual-time technology to obtain nonlinear unsteady aerodynamic load; the finite element co-rotational theory is applied to model geometric nonlinear structure, and an approximate energy conservation...
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