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A three dimensional (3-D) channel model including both stationary and moving scatterers for high altitude platforms (HAPs) multiple-input multiple-output (MIMO) communication systems is proposed in this paper. An M-step 2-state Markov process is incorporated into this model to depict the reappearance behavior of both scatterers. The survival probabilities of scatterers are derived by using Chapman-Kolmogorov...
Based on the linear relationship of channel data between synthetic transmit aperture (STA) and apodized plane wave (PW) firings, we previously proposed compressed sensing (CS) based STA (CS-STA) for linear array, which achieves higher frame rate and higher contrast-to-noise ratio (CNR) than STA while maintaining its high resolution. Because diverging wave (DW) instead of PW is usually adopted in phased...
Recently plane wave compounding was developed for high resolution convex array (CA) imaging (Bae et al IUS 2015). However, only elements whose directivities cover the plane wave direction were activated in each firing, leading to a narrowed imaging area and reduced frame rate. To solve this issue, we proposed Archimedean spiral (AS) based compounding (ASC) method for high quality and high frame rate...
Based on the linear relationship of channel data between synthetic transmit aperture (STA) and apodized plane wave (PW) firing, we previously proposed compressed sensing (CS) based STA (CS-STA) for linear array (Liu et al, IEEE TMI 2017), which achieves higher frame rate and higher contrast-to-noise ratio (CNR) than STA while maintaining its high resolution. Because diverging wave (DW) instead of...
In various control strategies of servo drive system, PI controllers are still used due to their simplicity and ease of design. Unfortunately, PID controllers are not robust and their performance is deteriorated when the operating conditions change due to parameter variations of the motor. A position control method of servo motor based on sliding mode controller (SMC) is proposed in this paper, for...
The major goal of this research is to study the influence of welding parameters on parallel-gap welding heat. And the welding heat is investigated on gold ribbon bonded on gold plating pad. Calculation of minimum welding heat is based on Fourier thermal conduction theory. Calculation results shows there is obvious threshold of welding current, and the threshold current is proven during lab experiment...
Grey catastrophe prediction can predict the date of catastrophe, so that people can take precautions in advance to reduce losses. For example, the use of catastrophe forecasting methods can predict the occurrence of disasters such as droughts, floods, landslides, typhoons and coal mine accidents, which is conducive to the government, relevant departments and the public to take corresponding actions...
We demonstrated a Fabry-Perot (FP) fiber cavity for strain measurement. The cavity is fabricated by fusion splicing two etched single-mode fibers (SMFs) with core offset in X axis. It is found that the strain sensitivity can be increased from 1.67 to 3.14 pm/με by adopting offset splicing. Such FP cavity is of low cost, compact in size, simple in structure and easy in fabrication, and has high potential...
Cuffless technology for blood pressure (BP) measurement offers great potential for unobtrusive monitoring of hypertension. However, the accuracy is still a challenging issue probably owning to the inadequacy of existing noninvasive BP indicators in tracking BP changes, i.e., either the poor trackability of the indicators or the lack of relationship to map the indicators to BP. To figure out the covariation...
For modelling hybrid systems, we have extended Event B based on its framework with the differential event. The differential event describes continuous behaviors of hybrid systems by differential equations and evolution constraint, whose proof obligations provide dynamical properties of a model. In order to ensure the safety and reliability of a model, proof obligations should be proved. It is difficult...
To validate whether RESTful Web service systemscould provide available services, it is indispensable to perform efficient and effective functional testing before their large-scale deployment, where the pivotal and first step is to automatically generate valid test data. In this paper, we develop a parallelized and automated test data generation tool based on the Hadoop, where mutation testing and...
A new model for image segmentation based on the theory of curve evolution is proposed, which is an improvement of the region-based active contour models. A weighted area term is added into the RSF model, and the coefficient in the area term is changed to a weighted coefficient of robust adaptivity. We use the model to segment medical images. The results show that the new model can reflect the complicated...
In this paper, a fuzzy tracking control strategy for a quad-rotor unmanned aerial vehicle (UAV) with strongly coupling is put forward based on the Takagi-Sugeno(T — S) fuzzy error model. Firstly, The quad-rotor system is divided into altitude subsystem, position subsystem and attitude subsystem, selecting appropriate premise variables, the attitude, altitude and position T — S fuzzy error models are...
A full reconstruction method of focal-field distribution using compressed sensing (CS) is presented. Exploring focal-field distribution characteristics, a proper sparsifying basis is constructed via the Kronecker product. The full distribution data can be obtained by solving a l1-norm minimization problem. Three scenarios are set up to verify the effectiveness of the proposed method. Simulation results...
In this paper, a novel approach of direction of arrival (DOA) estimation for large parabolic reflector antenna based on focal-field distributions is proposed. First through simulation, we get the focal field distribution with different incident direction. And then the data received by the array feed is restored by interpolation algorithm. Finally the direction of incoming plane wave can be identified...
Providing fault tolerance services to cloud applications is significant. This paper proposes a novel fault tolerance service provisioning scheme. First, fault tolerant requirements is defined from the reliability of cloud application components, application response time and fault tolerance effects. Then, an optimal fault tolerance service provisioning method is developed based on replication, N-version...
Deep convolutional neural networks (CNN) have recently been shown to generate promising results for aesthetics assessment. However, the performance of these deep CNN methods is often compromised by the constraint that the neural network only takes the fixed-size input. To accommodate this requirement, input images need to be transformed via cropping, warping, or padding, which often alter image composition,...
With the increase of the imaging resolution, the resulting enormous amount of sampling raw data aggravates transmission and storage load for multi-channel synthetic aperture radar (SAR) system. Considering the fact that the correlation among the dual-channel SAR images is high, we propose a Bayesian compressive sensing (BCS) based SAR imaging algorithm for ground moving targets indication (GMTI) system,...
We present a novel joint detection and tracking algorithm using raw measurements, in a compressed sensing framework. The sparse vector representing the state space is directly reconstructed, which transforms the nonlinear estimation problem into a linear one through sparse representation. A number of significant grids are obtained based on the sparse vector, indicating the positions of multiple potential...
This paper presents a compressed sensing based sensor selection algorithm for direction-of-arrival estimation, in a large scale randomly distributed sensor array. First, a target tracker is employed for the prior information of target position. Second, according to the prior information, we reduce rank of sensing matrix by narrowing the interesting area. Third, a linear independence combination of...
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