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Search Results: 1 - 10 of 126810 matches for " Chao Wang "
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Contention-Based Beaconless Real-Time Routing Protocol for Wireless Sensor Networks  [PDF]
Chao Huang, Guoli Wang
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.201027065
Abstract: This paper presents a novel real-time routing protocol, called CBRR, with less energy consumption for wireless sensor networks (WSNs). End-to-End real-time requirements are fulfilled with speed or delay constraint at each hop through integrating the contention and neighbor table mechanisms. More precisely, CBRR maintains a neighbor table via the contention mechanism being dependent on wireless broadcast instead of beacons. Comprehensive simulations show that CBRR can not only achieve higher performance in static networks, but also work well for dynamic networks.
On consistency and ranking of alternatives in uncertain AHP  [PDF]
Liang Lin, Chao Wang
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.45047
Abstract: This paper introduces uncertainty theory to deal with non-deterministic factors in ranking alternatives. The uncertain variable method (UVM) and the definition of consistency for uncertainty comparison matrices are proposed. A simple yet pragmatic approach for testing whether or not an uncertainty comparison matrix is consistent is put forward. In cases where an uncertainty comparison matrix is inconsistent, an algorithm is used to generate consistent matrix. And then the consistent uncertainty comparison matrix can derive the uncertainty weights. The final ranking is given by uncertainty weighs if they are acceptable; otherwise we rely on the ranks of expected values of uncertainty weights instead. Three numerical examples including a hierarchical (AHP) decision problem are examined to illustrate the validity and practicality of the proposed methods.
SAR Imaging of Moving Target Based on Quadratic Phase Function  [PDF]
Chao Wang, Shaobin Li
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.43B003

In this paper, a novel signal processing technique hasbeen developed to refocus moving targets image from their smeared responses in the Synthetic Aperture Radar (SAR) image according to the characteristics of the received signals for moving targets. Quadratic Phase Function is introduced to the parameters estimation for moving target echo and SAR imaging. Our method is available even under a low SNR environment and acquiring an exact SAR image of moving targets. The simulated results demonstrated the validity of the algorithm proposed.

The Role of the Composition of the Human Capital on the Economic Growth: With the Spatial Effect among Provinces in China  [PDF]
Ying Wang, Chao Ni
Modern Economy (ME) , 2015, DOI: 10.4236/me.2015.66073
Abstract: Based on the data of China’s 28 provinces and regions during 1987-2007, this paper is trying to explore the role of the composition of the human capital on the economic growth with the spatial effect among provinces. The results indicate that there are significant spatial effects of human capital and economic growth in China; there is a significant positive correlation between the GDP per capita and the average schooling years; when the education of human capital is divided into primary education, secondary education and higher education, only the higher education and the primary education show significantly positive correlation with the GDP per capita.
The Impact of Perceived Organizational Support and Core Self-Evaluation on Employee’s Psychological Well-Being  [PDF]
Chao Ni, Ying Wang
Journal of Human Resource and Sustainability Studies (JHRSS) , 2015, DOI: 10.4236/jhrss.2015.32011
Abstract: Psychological well-being (PWB) is a concept different from subjective well-being in positive psychology. PWB is conceptualized as a construct which includes the happy emotional experience and the realization of individual potential. This paper assumes that employee’s core self-evaluation and their perceived organizational support have a positive effect on psychological well-being. The result based on 441 valid questionnaires supports our hypothesis that employee’s core self-evaluation and their perceived organizational support are positively related to their reported psychological well-being. Core self-evaluation is also found to moderate the association of perceived organizational support with PWB in such that POS is more strongly related to PWB for employees who are higher, compared with those lower in CSE.
Combined Focusing and Flat-Field Spectrometer System for Extreme Ultraviolet Pulse  [PDF]
Yifan Kang, Chao Wang
Optics and Photonics Journal (OPJ) , 2017, DOI: 10.4236/opj.2017.78B003
For reducing both extreme ultraviolet attosecond pulses energy loss in the focusing reflection process and measurement error caused by pulse focusing aberration, as well as improving the operability of pulse spectroscopy monitoring, a combined focusing and flat-field spectrometer analysis system for attosecond pulse is proposed and designed through step-by-step performance optimization. The focusing and spectrum-analyzing components are gold- coated grazing incidence to roidal mirror and grazing incidence concave focusing grating, respectively. The characteristic parameters of the system are given in details. The system proposed can find application in research platform of attosecond spectroscopy using high energy short attosecond pulse as basic probe tool.
Compressing Electron Pulse with Alternating Electric Field  [PDF]
Chao Wang, Yifan Kang
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.611192
A novel technique of symmetric type quasi-linear electron pulse duration modulation is proposed. The salient feature from the conventional photoelectron gun is the introduction of the alternating electric field resonator. The electric field that results is synchronously controlled to generate the desired quasi-linear differential energy modulation on the electron pulse passing through. The effect resulted directly is that the leading electrons undergo negative energy modulation and decelerate, while the rear ones positive energy modulation and accelerate, which eventually leads to electron-pulse-duration modulation. The technical details are demonstrated.
Collision free autonomous navigation and formation building for non-holonomic ground robots
Chao Wang
Mathematics , 2014,
Abstract: The primary objective of a safe navigation algorithm is to guide the object from its current position to the target position while avoiding any collision with the en-route obstacles, and the appropriate obstacle avoidance strategies are the key factors to ensure safe navigation tasks in dynamic environments. In this report, three different obstacle avoidance strategies for safe navigation in dynamic environments have been presented. The biologically-inspired navigation algorithm (BINA) is efficient in terms of avoidance time. The equidistant based navigation algorithm (ENA) is able to achieve navigation task with in uncertain dynamic environments. The navigation algorithm algorithm based on an integrated environment representation (NAIER) allows the object to seek a safe path through obstacles in unknown dynamic environment in a human-like fashion. The performances and features of the proposed navigation algorithms are confirmed by extensive simulation results and experiments with a real non-holonomic mobile robot. The algorithms have been implemented on two real control systems: intelligent wheelchair and robotic hospital bed. The performance of the proposed algorithms with SAM and Flexbed demonstrate their capabilities to achieve navigation tasks in complicated real time scenarios. The proposed algorithms are easy to be implemented in real time and costly efficient. An extra study on networked multi-robots formation building algorithm is presented in this paper. A constructive and easy-to-implement decentralised control is proposed for a formation building of a group of random positioned objects. Furthermore, the problem of formation building with anonymous objects is addressed. This randomised decentralised navigation algorithm achieves the convergence to a desired configuration with probability 1.
Head Frontal-View Identification Using Extended LLE
Chao Wang
Computer Science , 2012,
Abstract: Automatic head frontal-view identification is challenging due to appearance variations caused by pose changes, especially without any training samples. In this paper, we present an unsupervised algorithm for identifying frontal view among multiple facial images under various yaw poses (derived from the same person). Our approach is based on Locally Linear Embedding (LLE), with the assumption that with yaw pose being the only variable, the facial images should lie in a smooth and low dimensional manifold. We horizontally flip the facial images and present two K-nearest neighbor protocols for the original images and the flipped images, respectively. In the proposed extended LLE, for any facial image (original or flipped one), we search (1) the Ko nearest neighbors among the original facial images and (2) the Kf nearest neighbors among the flipped facial images to construct the same neighborhood graph. The extended LLE eliminates the differences (because of background, face position and scale in the whole image and some asymmetry of left-right face) between the original facial image and the flipped facial image at the same yaw pose so that the flipped facial images can be used effectively. Our approach does not need any training samples as prior information. The experimental results show that the frontal view of head can be identified reliably around the lowest point of the pose manifold for multiple facial images, especially the cropped facial images (little background and centered face).
Uncertainty Weight Generation Approach Based on Uncertainty Comparison Matrices  [PDF]
Chao Wang, Liang Lin, Jiajun Liu
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.35075
Abstract: In practical application of AHP, non-deterministic factors are frequently encountered. This paper employs uncertainty theory to deal with non-deterministic factors in problems of ranking alternatives. The concepts of uncertainty comparison matrix and uncertainty weights are proposed in this paper. It also gives the uncertain variable method to calculate uncertainty weights from uncertainty comparison matrices, which can be either consistent or inconsistent. The proposed uncertain variable method (UVM) is also applicable to interval comparison matrices and fuzzy comparison ma-trices when they are transformed into uncertainty comparison matrices using linear uncertainty distribution or zigzag uncertainty distribution. The proposed approach is computationally efficient as it consists of solving only inverse uncertainty distribution. At the end of this paper, five numerical examples are given to illustrate the method.
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