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Search Results: 1 - 10 of 21080 matches for " GAO Shuang "
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Inertial Aided Cycle Slip Detection and Identification for Integrated PPP GPS and INS
Shuang Du,Yang Gao
Sensors , 2012, DOI: 10.3390/s121114344
Abstract: The recently developed integrated Precise Point Positioning (PPP) GPS/INS system can be useful to many applications, such as UAV navigation systems, land vehicle/machine automation and mobile mapping systems. Since carrier phase measurements are the primary observables in PPP GPS, cycle slips, which often occur due to high dynamics, signal obstructions and low satellite elevation, must be detected and repaired in order to ensure the navigation performance. In this research, a new algorithm of cycle slip detection and identification has been developed. With the aiding from INS, the proposed method jointly uses WL and EWL phase combinations to uniquely determine cycle slips in the L1 and L2 frequencies. To verify the efficiency of the algorithm, both tactical-grade and consumer-grade IMUs are tested by using a real dataset collected from two field tests. The results indicate that the proposed algorithm can efficiently detect and identify the cycle slips and subsequently improve the navigation performance of the integrated system.
Post Evaluation of Wind Resource Assessment and Micro-Siting  [PDF]
Shuang Han, Linyue Gao, Yongqian Liu, Wei Yang
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24040
Abstract: The design energy productions deviate from the actual situation, which are affected by the accuracy of two significant factors - the wind resource assessment and wind farm micro-siting. A running wind farm in northern China was taken as the object in this investigation. The measured data obtained in operation phase and the relevant information in design phase were integrated and a post evaluation of wind resource assessment, micro-siting and generating capacity reduction factors of the wind farm in design phase was provided. The results indicate that the representative year wind regimes of the wind farm in design phase can basically reflect the wind conditions in the wind farm without the consideration of the trends of long-term changes in wind speed; micro-siting project in design phase is superior to that in practical; generating capacity reduction factors, overall on the high side, should be further optimized considering 20-year operation period.
Study on Effect of UHV Power Grid Construction Schemes on Short Circuit Current  [PDF]
Zaihua Li, Feng Gao, Qing Wang, Shuang Zhang, Hongmei Luo, Jian Liang
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.34028
Abstract:

The commissioning of Southern Hami-Zhengzhou ±800 kV UHVDC transmission project has important significance to heighten operation reliability, transfer capability and supply electric ability of Henan power grid. However, short circuit currents of 500 kV buses in the Center of Henan are almost close to the operation upper limitation. In order to decrease the short circuit currents effectively, it’s necessary to strengthen the network structure of Center of Henan power grid and calculate short circuit currents. Two schemes of strengthening the network structure of Center of Henan power grid are studied. The calculated values of short circuit currents of some important 500 kV buses in the two schemes are still bigger than excepted. According to the latest Plan of State Grid, Yubei UHV substation and Zhumadian UHV substation located in Henan power grid. The calculated values of short circuit currents of some important 500 kV buses with the commissioning of Yubei UHV and Zhumadian UHV are qualified. So, reasonable network structure with UHV is suitable to heighten transfer capability and supply electric ability of Henan power grid.

Simulation Study on Series Capacitor Compensation to Improve the Voltage Quality of Rural Power Distribution Network  [PDF]
Hongqiang Li, Feng Gao, Xutao Li, Shaogui Ai, Shuang Zhang, Bei Tian
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C027
Abstract:

In order to improve the voltage quality of rural power distribution network, the series capacitor in distribution lines is proposed. The principle of series capacitor compensation technology to improve the quality of rural power distribution lines voltage is analyzed. The real rural power distribution network simulation model is established by Power System Power System Analysis Software Package (PSASP). Simulation analysis the effect of series capacitor compensation technology to improve the voltage quality of rural power distribution network, The simulation results show that the series capacitor compensation can effectively improve the voltage quality and reduce network losses and improve the transmission capacity of rural power distribution network.

Optimal quantum measurement of finite-dimensional systems and coherent anti-Stokes Raman spectroscopy
Fang Gao,YaoXiong Wang,Feng Shuang
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5182-3
Abstract: Quantum measurement is a fundamental problem in quantum control theory and experiments. It can obtain unknown information of quantum systems, and can also change state of the systems inevitably. Both the outcome and back action could be used to control quantum systems. This paper presents recent research progress about optimal control of state transformation in finite-dimensional quantum systems by back action of non-selective quantum measurement, and optimal control of signal and background of CARS (coherent anti-Stokes Raman spectroscopy) by phase shaping technique. In measurement sequence control of finite-dimensional quantum systems, the necessary condition for critical points of the underlying state transformation objective is found to be a highly symmetric form as a chain of equalities, and analytical and numerical solutions in several cases are explored. In the CARS control, it is found that the maximal resonant signal and minimal background at a specific frequency can be achieved by shaping the probe pulse only while keeping pump and Stokes pulses in transform limited forms (TLFs). An arctan-type phase function is obtained for the probe pulse to simultaneously enhance the resonant signal and suppress the background. For broadband background elimination, we find that the optimal phase shaping scheme of probe pulse is quasi-time-delay while keeping the pump and Stokes pulses in TLFs. These conclusions could help design control strategies of quantum devices.
A Comparison of Two Similarity Measures in Intensity-based Ultrasound Image Registration
两种基于灰度相似性测度的超声波图像配准方法的比较

GAO Shuang,XIAO Yang,
高爽
,肖扬

中国图象图形学报 , 2006,
Abstract: Image registration is a basic problem during image analysis and image processing. Image registration has been widely applied in the fields of medical image, remote sensing and computer vision. This paper investigates two registration methods for ultrasound image relying on the intensity-based similarity measure. In tiw first method intensity information is provided by feature points which have been extracted using Harris corner detector. The registration similarity measure is then defined as a cost-function-error cost function. In the latter method the same cost-function is employed, but uniqueness control and region correspondence are different from the first method. Given this similarity measure, parametric ultrasound image registration is stated as a minimization issue. The experiment even exploits polynomial technique to transform the whole image dataset and estimates the sum of square error in the first method. Image quality is one of the most important issues in ultrasound imaging. Ultrasound images tend to be noisy due to the presence of speckle. Speckle originates from the constructive-destructive interference of the ultrasound pulses, and is produced to some extent by all ultrasound machines. This paper shows that it is possible to perform accurate registration on data from in-vivo examinations. The result indicates that the two methods are robust and meet our requirements, but the latter outperforms the first one. It can match B-scans and areas with certain angel, severe deformation and even with plus noise.
Higher Dimensional Reissner-Nordstr?m-FRW metric
Chang Jun Gao,Shuang Nan Zhang
Physics , 2004, DOI: 10.1007/s10714-005-0207-8
Abstract: By inspecting some known solutions to Einstein equations, we present the metric of higher dimensional Reissner-Nordstr$\ddot{o}$m black hole in the background of Friedman-Robertson-Walker universe. Then we verify the solution with a perfect fluid. The discussion of the event horizon of the black hole reveals that the scale of the black hole would increase with the expansion of the universe and decrease with the contraction of the universe.
Reissner-Nordstr?m Metric in the Friedman-Robertson-Walker Universe
Chang Jun Gao,Shuang Nan Zhang
Physics , 2004, DOI: 10.1016/j.physletb.2004.05.076
Abstract: The metric for a Reissner-Nordstr$\ddot{o}$m black hole in the background of the Friedman-Robertson-Walker universe is obtained. Then we verified it and discussed the influence of the evolution of the universe on the size of the black hole. To study the problem of the orbits of a planet in the expanding universe, we rewrote the metric in the Schwarzschild coordinates system and deduced the equation of motion for a planet.
Towards a fully consistent Milky Way disc model - II. The local disc model and SDSS data of the NGP region
Andreas Just,Shuang Gao,Simon Vidrih
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.17866.x
Abstract: We have used the self-consistent vertical disc models of the solar neighbourhood presented in Just & Jahreiss (2010), which are based on different star formation histories (SFR) and fit the local kinematics of main sequence stars equally well, to predict star counts towards the North Galactic Pole (NGP). We combined these four different models with the local main sequence in the filter system of the SDSS and predicted the star counts in the NGP field with b>80deg. All models fit the Hess diagrams in the F-K dwarf regime better than 20 percent and the star number densities in the solar neighbourhood are consistent with the observed values. The chi^2 analysis shows that model A is clearly preferred with systematic deviations of a few percent only. The SFR of model A is characterised by a maximum at an age of 10Gyr and a decline by a factor of four to the present day value of 1.4Msun/pc^2/Gyr. The thick disc can be modelled very well by an old isothermal simple stellar population. The density profile can be approximated by a sech^(alpha_t) function. We found a power law index alpha_t=1.16 and a scale height of 800pc corresponding to a vertical velocity dispersion of 45.3km/s. About 6 percent of the stars in the solar neighbourhood are thick disc stars.
Detailed comparison of Milky Way models based on stellar population synthesis and SDSS star counts at the north Galactic pole
Shuang Gao,Andreas Just,Eva K. Grebel
Physics , 2012, DOI: 10.1051/0004-6361/201118243
Abstract: We test the ability of the TRILEGAL and Besancon models to reproduce the CMD of SDSS data at the north Galactic pole (NGP). We show that a Hess diagram analysis of colour-magnitude diagrams is much more powerful than luminosity functions (LFs) in determining the Milky Way structure. We derive a best-fitting TRILEGAL model to simulate the NGP field in the (g-r, g) CMD of SDSS filters via Hess diagrams. For the Besancon model, we simulate the LFs and Hess diagrams in all SDSS filters. We use a chi2 analysis and determine the median of the relative deviations in the Hess diagrams to quantify the quality of the fits by the TRILEGAL models and the Besancon model in comparison and compare this with the Just-Jahreiss model. The input isochrones in the colour-absolute magnitude diagrams of the thick disc and halo are tested via the observed fiducial isochrones of globular clusters (GCs). We find that the default parameter set lacking a thick disc component gives the best representation of the LF in TRILEGAL. The Hess diagram reveals that a metal-poor thick disc is needed. In the Hess diagram, the median relative deviation of the TRILEGAL model and the SDSS data amounts to 25 percent, whereas for the Just-Jahreiss model the deviation is only 5.6 percent. The isochrone analysis shows that the representation of the MS of (at least metal-poor) stellar populations in the SDSS system is reliable. In contrast, the RGBs fail to match the observed fiducial sequences of GCs. The Besancon model shows a similar median relative deviation of 26 percent in (g-r, g). In the u band, the deviations are larger. There are significant offsets between the isochrone set used in the Besancon model and the observed fiducial isochrones. In contrast to Hess diagrams, LFs are insensitive to the detailed structure of the Milky Way components due to the extended spatial distribution along the line of sight.
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