The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Retrieving a small set of relevant and interesting objects from a large background class is challenging because classifiers can easily be overwhelmed by the large class. Classifiers have been developed that are more sensitive to the small class, and typically they optimize a ranking, or precision at the top. These measures can be costly because they often look at pairwise rankings. The classical approach...
Feature selection is an effective technique for dimensionality reduction to get the most useful information from huge raw data. Many spectral feature selection algorithms have been proposed to address the unsupervised feature selection problem, but most of them fail to pay attention to the noises induced during the feature selection process. In this paper, we not only consider the feature structural...
In this paper, we develop the robust transceiver optimization for the multiple-input single-output (MISO) interference channels where each transmitter (Tx) is equipped with multiple antennas and each single-antenna receiver performs simultaneous wireless information and power transfer (SWIPT) based on a power-splitting architecture. Assuming imperfect channel state information (CSI) at the Txs, we...
Secret sharing is a very important branch in the field of modern cryptography. Secret image sharing technology is the expansion of secret sharing in terms of image. When using this technology to share images, it can ensure the integrity and security of the image. In this paper, secret image used random shadow image which is generated from (t, n) threshold secret image sharing scheme. This paper adopted...
We consider the transmit beamforming design for a multi-user downlink with multiple transmit antennas at the base station. Different from the conventional sum-power constraint across the transmit antennas, we assume individual power constraints per antenna. Assuming that perfect channel state information (CSI) is available at the base station, we develop an efficient algorithm to find the optimal...
The correspondence between key points is an important problem in lunar surface image processing, and further lays the foundation for the navigation of a rover and the terrain reconstruction of the lunar surface. However, the problem is still challenging due to the existence of large scale and rotation transformations, reflected view of the same scenery, and different illumination conditions between...
A robust nonlinear controller is developed for the formation flying system. Using a nonlinear model directly, the Polynomial Eigenstructure Assignment approach is applied to complete controller design. The resulting controller can produce a closed-loop system with invariant performance over a wide range of conditions. Taking two sources of uncertainty, the robust D-stability is assessed by using the...
For the disadvantage of the low flux's observational accuracy of induction motor direct torque control system when it runs in a low velocity, the full order flux observer is used to achieve the stator flux observation.Based on the analysis of four full order flux observer pole placement methods,The impact on observational accuracy and convergence rate was researched with different parameters of the...
Visual attention model is a hotspot in the field of multimedia understanding. It is quite helpful for multimedia processing especially in the case that the human vision should be considered. In this paper, a novel information hiding algorithm based on Stentiford visual attention model is proposed. By embedding less information in sensitive region, the invisibility of image with hidden information...
Voronoi diagram(VD) is a fundamental data structure in computational geometry. With the rapid development of programmable graphics programmable units, utilizing GPU to construct VD has been an optimal strategy. Considering the bridles of state-of-art algorithms, a seed flooding algorithm(SFA) is presented to achieve both robustness and high performance. The experimental results shows that SFA can...
This paper presents a parameter identification method of nonlinear Hammerstein model with two-segment piecewise nonlinearities. Its basic idea is that: First of all, expressing the output of the Hammerstein nonlinear models as a regressive equation in all parameters based on the key term separation principle and separating key term from linear block and nonlinear block. Then, the unknown true outputs...
A nonlinear controller is designed for a L2 formation flying control system, and robust stability is investigated for the closed-loop system with uncertainties. The L2 formation flying is modeled as a second-order quasi-linear parameter-varying model, which is obtain from the nonlinear formation flying model with Barbashin method by including explicit dependence of the dynamic derivatives on states...
A nonlinear controller based on polynomial eigen-structure assignment (PEA) is presented for a class of nonlinear systems. In this paper, the PEA approach used for LTI and LPV models is extended to QLTV model to realize the desired control performance of closed-loop system. With PEA approach, the eigenstructure assignment for the controller can be completed without imposing any particular eigenvalues...
Inverted pendulum is a control system, with the feature of high order, muti-variable, non-linearity and unstable naturally. It is quite important for us to study its balance and stability in control engineering field. In this paper, a flywheel inverted pendulum, as an object to be controlled, the dynamic model has been established, and the mathematical model which established has been certificated...
A new centralized and decentralized mixture control via virtual structure (VS) approach for the large number of spacecrafts formation flying is presented in this paper. To describe the formation clearly, the entire formation is considered as a main VS including several sub-VSs and every sub-VS includes several single spacecrafts. In this mixture control architecture, the decentralized architecture...
This paper presents active disturbance rejection control system for toggle-motor coupling servomechanism system. Genetic algorithm and mixed H2/Hinfin norm index are utilized to optimize the system parameters; Monte-Carlo method is applied to evaluate the robustness of the control system. Simulation results show that under the condition of external disturbance, parameters perturbation and coupling,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.