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Many challenges of modeling and control exist in the tail-sitter aircraft, including parameter uncertainty, highly coupling, nonlinearity, and external disturbance. In this paper, the model of a tail-sitter aircraft is simplified at the nominal condition to obtain the nominal linear invariant model. Then a robust controller based on the H∞ control theory is proposed to deal with the attitude tracking...
We present a method to improve the isolation bandwidth of electromagnetic soft surfaces based on the inclusion of non-Foster components between metallic strips. Compared with the design of traditional soft surfaces, the proposed method exhibits not only a broader bandgap but also a lower stopband frequency for broadband and miniaturization purposes. Thus, this new method is attractive for reducing...
This research introduces a low-power, light-weight wearable powered waist exoskeleton with mechanical clutch. By processing the signals from multiple sensors, the human movement intention can be precisely identified and estimated. The exoskeleton can help reduce the work done by human muscle and has a loading capacity up to 20kg. Through the mechanical clutches applied, the exoskeleton can lock the...
In this paper, we design a novel knee exoskeleton. The designed exoskeleton has a 1 DOF with knee joint actuated in the sagittal plane. The exoskeleton is actuated base on Series Elastic Actuator (SEA) instead of traditonal stiff actuator. SEA is a compliant actuator, having the advantages of low output impedance, low friction, high quality force control and backdrivability. Thanks to these nice characteristics,...
The detection and extraction of buildings using high resolution synthetic aperture radar (SAR) images has been the topic of recent discussions. In this paper, a framework for building extraction and classification is proposed. Buildings are classified into three kinds: commercial architecture, residential building and Industrial building, by the fusion of structure features (point-like, linear and...
We have theoretically analyzed the diffractive characteristics of radiation mode of 45° tilted fiber gratings. The simulated angular dispersion for the 45 ° TFG with 748nm period at 1550nm is around 0.053°/nm, which is quite close to the experimental result.
This paper displays a case study which accomplishes crop classification of simulated compact polarimetric (CP) SAR and fully polarimetric (FP) SAR images with Random Forest. Since the potential of CP SAR in classification has been illustrated by various researches, we intend to find out which of the polarimetric features are more superior in crop classification, through the importance rank of Random...
Ship classification with spaceborne high resolution synthetic aperture radar (SAR) has wide applications in maritime traffic monitoring, fishing law-enforcement operation, marine security, etc. Deep learning, which has the ability of learning features itself, is successfully used in computer vision and artificial intelligence, and introduced into remote sensing field in recent years. In this study,...
Change detection is a hot issue and is of great significance in remote sensing. The logarithm operation is a valid way to reduce the influence of multiplicative noise in the Synthetic Aperture Radar (SAR) image. However, changed areas with high gray level values will be weakened due to the nature of the logarithmic function. In this paper, a SAR image change detection framework based on visual attention...
Ship detection using synthetic aperture radar (SAR) is an important application in maritime transportation monitoring. However, azimuth ambiguities are inevitably caused by the undersampling of the echo signals, which can be easily mistaken as ship targets in the detection result. To solve the problem mentioned above, a fast object-oriented method for azimuth ambiguities removal based on quantitative...
To explore the capability of quad polarimetric SAR images from a new pursuit monostatic mode of TerraSAR-X and TanDEM-X, a novel process chain for ship detection and velocity estimation is proposed in this paper. Compared with the classic processing chain used for single SAR image, more efficient techniques are integrated into this novel chain, which take advantage of the new image mode and its excellent...
Owing to its advantages of being closed-loop and online as well as small memory storage length, adaptive extended Kalman filter (AEKF) based state of charge (SOC) estimation method for lithium batteries in electric vehicles (EVs) has been widely used. However, EVs often have to operate under complex conditions, such as sudden acceleration and deceleration. Under the strong nonlinear input, the AEKF...
We propose and investigate an ultra-compact dual-parameter sensor for simultaneous detection of concentration and temperature using the 0th-order and the 1st-order modes of a single photonic crystal rectangular holes nanobeam multimode microcavity (PC-RNMC).
We design highly sensitive one chip multichannel sensor array by using a 1×8 power splitter, eight one dimensional photonic crystal slot nanobeam cavities connected by additional bandgap filters, and an 8×1 coupler. The structure is lying on top of a 2 μm buried SiOi layer, while remaining high sensitivities (over 400 nm/RIU) of all sensors.
The hydrologic monitoring is of great importance to the water resources management, ecological environment protection. The equipment and methods used in hydrological monitoring are various, the data types are complex and diverse. There are various causes of the hydrological disasters, and they are interrelated and interactional. This paper summarizes the main hydrological monitoring sensors, observations...
Data compressed photonic time stretch optical coherence tomography system enables high speed signal detection with reduced bandwidth requirement for backend electronic and digitizers. However, the measurement resolution is inherently dependent on the repetition rate of mode-locked laser. This work reports a new approach to improve depth profile resolution based on dual pulse integration. In our experimental...
Synonyms extraction is a fundamental research, which is helpful to text mining and information retrieval. In this paper, we propose method to extract synonymy from text, the method employs spectral clustering and word2vec. First, the word2vec model is trained by a large-scale English Wikipedia corpus. Then, we extract keywords from a text and use the trained model to generate similarities among these...
Cognitive radio (CR) is the enabling technology for supporting dynamic spectrum access. This sort of communication paradigm can utilize increasingly scarce spectrum resources more efficiently and has become one of the the hot issues of wireless communication in recent years. With in-depth research, some unique security risks of the CR network has been revealed. A new method named RF "Distinct...
A smart ternary strategy was designed to improve the performance of ternary polymer solar cells (TPSCs) by doping high-mobility conjugated polymer poly{2, 2'-(2,5-bis(2-octyldodecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3, 4-c]pyrrole-1, 4-diyl)dithieno[3, 2-b]thiophene-5,5'-diyl-alt-thiophen-2,5-diyl} (PDPPBTT) into the dominating poly({4,8-bis[(2-ethylhexyl)oxy] benzo[1,2-b:4,5-b′] dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethy-lhexyl)carbonyl]thieno[3,4-b]thiophenediyl})...
With the development of deep learning and artificial intelligence, more and more research apply neural networks to natural language processing tasks. However, while the majority of these research take English corpus as the dataset, few studies have been done using Chinese corpus. Meanwhile, Existing Chinese processing algorithms typically regard Chinese word or Chinese character as the basic unit...
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