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The vertical electron density distribution can have a significant impact on ionospheric measurements of Total Electron Content (TEC) derived from estimates of Faraday rotation (FR) with spaceborne low-frequency SAR data. Using vertical electron density data and the IGRF-12 magnetic field model, simulations of FR under different vertical electron density distributions for an L-band SAR have been performed...
SAR image segmentation is the pre-process for SAR image application. This paper presents a new SAR image segmentation algorithm combining both the the bias field and Markov random field(MRF) characteristic with fuzzy clustering model(FCM) called BMFCM. The MRF characteristic of an image includes the spatial information of the image and the bias filed estimation is introduced to deal with the grey...
Comparing with the traditional global navigation satellite system (GNSS) based Bistatic SAR (GNSS-based BiSAR), the BiSAR based on GPS-L5 signal plays a superior role in remote sensing applications, as for its feature of stronger power and larger bandwidth. In applying this method, the consequent problems, yet, such as long dwell time and large range cell migration (RCM) are inevitably leading the...
The multi-azimuth-angle (MAA) UAV SAR is introduced in this paper. Compared with the traditional TomoSAR that rebuilds the 3-D scene only from the boresight aspect, the MAA UAV SAR can rebuild the 3-D scene from different multi azimuth angles and then provide multiple or even full aspects 3-D image by the novel 3-D image formation algorithm presented in this paper. Firstly, the MAA UAV SAR is introduced,...
Recently, electromagnetic (EM) vortex with orbital angular momentum (OAM) attracts more attention in radar imaging fields, which needs a variety of OAM modes. However, most of them are based on motion relative static. In this paper, we propose a novel SAR imaging method based on electromagnetic vortex with OAM. The geometry model of synthetic aperture radar (SAR) is utilized for EM vortex with OAM...
Time-sequential SAR image is product of multi-angle observation mode, which is widely used in moving targets detection and multi-directional information extraction. Utilizing the long integration time in spotlight/sliding spotlight SAR, it can generate a series of images of one scene during different periods of time. Focusing on the problem of high data redundancy and low efficiency in the process,...
Supercapacitors (SCs) are widely utilized as energy storage units (ESUs) to compensate the transient power fluctuations. In this paper, an improved virtual impedance based coordinated control strategy for distributed SCs is proposed to achieve accurate power distribution. Unlike the existed strategy which can hardly adjust the output power of each SC if the energy storage system contains several distributed...
Imbalanced dataset problem may occur when the number of instances of a certain class is much lower than others, resulting in a drop in the classification result of minority class. We propose the method of generating images from 3D modeling by some softwares to get enough images of minority class and supplement the dataset to re-balance it. Several deep networks are trained on these datasets. The experiment...
In this paper, we concentrate on multi-target fusion and tracking problems in wireless sensor network (WSN) based on distributed clustering consensus filter. In particular, for the sake of the network lifetime and the tracking accuracy in multi-target cases, a distributed target-based clustering algorithm is proposed, which consists of the cluster member selection, the cluster head competition and...
There are four main steps in the flying object hitting problem. Firstly, the position and velocity of the object need to be accurately predicted ahead of time. Secondly, feasible hitting poses need to be calculated. Thirdly, a fast motion planning algorithm for the robot needs to be implemented. Lastly, the inverse kinematics of the robot needs to be derived. In this paper, a six degrees-of-freedom...
Decentralized decision making with uncertainty is one of the fundamental challenges in multi-agent systems. Current approaches for multi-agent coordination which rely on continuous communication of team members, cannot be applied in the practical applications where loss of communication frequently occurs. For this problem, a role-based multi-agent model is presented for implicit coordination. The...
A method of improving the location accuracy of a target when imaged from an unmanned aerial vehicle (UAV) is described. This method focuses on improving estimation of heading angle bias to then improve geolocation performance. A Particle Swarm Optimization (PSO) algorithm is employed to derive an expression of optimal flight path, which can be a guide for trajectory planning. The aircraft is commanded...
This paper first investigates the challenging graph theoretic problem of constructing universally rigid tensegrity frameworks given any generic configuration. We design a numerical algorithm to construct a universally rigid tensegrity framework, such that the resulted eigenvalues of the stress matrix of the tensegrity framework can be selected beforehand. As one application, we then consider the formation...
Over the last decades, robots have been moved from industries to domestic environments. Robot Learning from Demonstration (LfD) is one of the most significant methods to facilitate this trend. In this work, we first discuss details about a efficient motion planning strategy, e.g., Stable Estimator of Dynamical Systems (SEDS). A human first demonstrates reaching tasks several times, and Gaussian Mixture...
Clustering techniques that group samples based on their attribute similarity have been widely used in many fields such as pattern recognition, feature extraction and malicious behavior characterization. Due to its importance, various clustering techniques have been developed with distributed frameworks such as K-means with Hadoop in Apache Mahout for scalable computation. While K-means requires the...
Ultrafast fiber lasers have been recognized as the efficient ultrashort pulse sources, which can be applied to various practical fields, such as material processing, fiber sensing, optical communication and medicine. To generate ultrashort pulse, the most efficient approach is the use of passive mode-locking techniques. So far, the passively mode-locked pulse duration ranging from femtosecond to picosecond...
While selecting a proper power system architecture for a more electric aircraft (MEA), it is the system volume and weight that is treated as the most important criterion by researchers. However, with the increased use of power electronics converters and motor drive systems, the system stability would be deteriorated. Therefore, the system stability issue should also be considered besides system volume...
The weapon target assignment (WTA) problem is a fundamental problem arising in defense-related applications of operations research. The multi-stage weapon target assignment (MWTA) problem is the basis of the dynamic weapon target assignment (DWTA) problem which commonly exists in practice. The MWTA problem considered in this paper is formulated as a multi-objective constrained combinatorial optimization...
Can venture capital (VC) firms transform a weak innovation ecosystem into a productive and robust one? While the literature has found VC firms' catalyst role in innovation in developed markets, we know little about whether and how they affect innovation in an emerging market, where formal legal- and market institutions and networks of professional intermediaries for them to play a catalyst role are...
Interactive multiobjective optimization (IMO) methods aim at supporting human decision makers (DMs) to find their most preferred solutions in solving multiobjective optimization problems. Due to the subjectivity of human DMs, human fatigue, or other limiting factors, it is hard to design experiments involving human DMs to evaluate and compare IMO methods. In this paper, we propose a framework of a...
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