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WANG Xinzhou,XU Chengquan 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-
Based on the possibility theory and the fuzzy set, the Maximum Possibility Estimation method and its applications in kinematic GPS positioning are presented in this paper. Firstly, the principle and the optimal criterion of the Maximum Possibility Estimation method are explained. Secondly, the kinematic GPS positioning model of single epoch single frequency with baseline length constraint is developed. Then, the authors introduce the artificial immune results of some examples show that the method is efficient for kinematic GPS positioning.
Traveling Wave Based Differential Protection for Renewable Energy Penetrated Power System
Wang Haozong,Dong Xinzhou 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3
Renewable sources such as solar and wind is the ideal solution for sustainable development. However, protection methods for renewable energy penetrated power systems still faces a lot of challenges. We claim that the performance of the diff erential protection is highly related to the model accuracy. Using a detailed distributed parameter line model, this paper developed a novel diff erential protection method for renewable energy penetrated power systems based on traveling waves with high rapidity and reliability. The optimal diff erential point is also discussed to enhance protection rapidity. Experiments demonstrate that the proposed protection could soon detect internal faults with high fault resistance while maintaining reliability when external faults occur.
Gate-tunable current partition in graphene-based topological zero lines
Wang, Ke,Ren, Yafei,Deng, Xinzhou,Yang, Shengyuan A.,Jung, Jeil,Qiao, Zhenhua American Physical Society 2017 Physical Review B Vol.95 No.24
<P>We demonstrate new mechanisms for gate-tunable current partition at topological zero-line intersections in a graphene-based current splitter. Based on numerical calculations of the nonequilibrium Green's functions and Landauer-Buttiker formula, we show that the presence of a perpendicular magnetic field on the order of a few Teslas allows for carrier sign dependent current routing. In the zero-field limit the control on current routing and partition can be achieved within a range of 10-90% of the total incoming current by tuning the carrier density at tilted intersections or by modifying the relative magnitude of the bulk band gaps via gate voltage. We discuss the implications of our findings in the design of topological zero-line networks where finite orbital magnetic moments are expected when the current partition is asymmetric.</P>
AC and DC Microgrids: A Review on Protection Issues and Approaches
Sohrab Mirsaeidi,Xinzhou Dong,Shenxing Shi,Bin Wang 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.6
Microgrid is a convenient, reliable, and eco-friendly approach for the integration of Distributed Generation (DG) sources into the utility power systems. To date, AC microgrids have been the most common architecture, but DC microgrids are gaining an increasing interest owing to the provision of numerous benefits in comparison with AC ones. These benefits encompass higher reliability, power quality and transmission capacity, non-complex control as well as direct connection to some DG sources, loads and Energy Storage Systems (ESSs). In this paper, main challenges and available approaches for the protection of AC and DC microgrids are discussed. After description, analysis and classification of the existing schemes, some research directions including coordination between AC and DC protective devices as well as development of combined control and protection schemes for the realization of future hybrid AC/DC microgrids are pointed out.
Xingsheng Deng,Xinzhou Wang 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-
The geoidal undulations are needed for determining the orthometric heights from the Global Positioning System GPS-derived ellipsoidal heights. There are several methods for geoidal undulation determination. The paper presents a method employing a simple architecture Two Layer Multiquadric-Biharmonic Artificial Neural Network (TLMB-ANN) to approximate an area of 4200 square kilometres quasigeoid surface with GPS-levelling data. Hardy’s Multiquadric-Biharmonic functions is used as the hidden layer neurons’ activation function and Levenberg-Marquardt algorithm is used to train the artificial neural network. In numerical examples five surfaces were compared: the gravimetric geometry hybrid quasigeoid, Support Vector Machine (SVM) model, Hybrid Fuzzy Neural Network (HFNN) model, Traditional Three Layer Artificial Neural Network (ANN) with tanh activation function and TLMB-ANN surface approximation. The effectiveness of TLMB-ANN surface approximation depends on the number of control points. If the number of well-distributed control points is sufficiently large, the results are similar with those obtained by gravity and geometry hybrid method. Importantly, TLMB-ANN surface approximation model possesses good extrapolation performance with high precision.
Study on the Application of GPS to Monitoring Land Subsidence
Cheng Shu,Wang Xinzhou 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-
There are many problems which takes long time and lots of work to monitor land subsidence by traditional method. These problems can be solved by GPS. Combining with the field example, this paper studies the application of GPS to monitoring land subsidence, analyses the advantages and errors of GPS survey method, and puts forth the suitable conditions of monitoring land subsidence by GPS.
AC and DC Microgrids: A Review on Protection Issues and Approaches
Mirsaeidi, Sohrab,Dong, Xinzhou,Shi, Shenxing,Wang, Bin The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.6
Microgrid is a convenient, reliable, and eco-friendly approach for the integration of Distributed Generation (DG) sources into the utility power systems. To date, AC microgrids have been the most common architecture, but DC microgrids are gaining an increasing interest owing to the provision of numerous benefits in comparison with AC ones. These benefits encompass higher reliability, power quality and transmission capacity, non-complex control as well as direct connection to some DG sources, loads and Energy Storage Systems (ESSs). In this paper, main challenges and available approaches for the protection of AC and DC microgrids are discussed. After description, analysis and classification of the existing schemes, some research directions including coordination between AC and DC protective devices as well as development of combined control and protection schemes for the realization of future hybrid AC/DC microgrids are pointed out.
GPS phase measurement cycle-slip detection based on a new wavelet function
ZHENG Zuoya,LU Xiushan,WANG Xinzhou,CHEN Chuanfa 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2 No.-
Presently, cycle-slip detection is done between adjacent two points in many cycle-slip methods. Inherently, it is simple wavelet analysis. A new idea is put forward that the number of difference point can adjust by a parameter factor; we study this method to smooth raw data and detect cycle-slip with wavelet analysis. Taking CHAMP satellite data for example, we get some significant conclusions. It is showed that it is valid to detect cycle-slip in GPS phase measurement based on this wavelet function, and it is helpful to improve the precision of GPS data pre-processing and positioning.
A Longitunal Study on Young Children's Development of the Representation of Written Number Symbols
Xin Zhou,Jianhong Wang 한국유아교육학회 2006 INTERNATIONAL JOURNAL OF EARLY CHILDHOOD EDUCATION Vol.12 No.1
Young children’s representation of written number symbols was examined at 4 time points during two years (mean age=55, 64, 70 & 76 months). Measurements were Number Symbol Representation Task; Cardinal Concept Task; Written Addition and Subtraction Task and Written Arithmetic Formula Representation Task. The results indicated children’s rapid development in the ability to represent written number symbols. Scores on Written Number Symbolic Tasks, Cardinal Concept and Written Addition and Subtraction Task were significantly correlated. Performance of children in university affiliated childcare center surpassed that of the center serving working families at Time 1, but the advantage of the center faded at Time 3 and Time 4. A multiple regression analysis identified 2 significant predictors for children’s representation of written number symbols at the end of kindergarten: written number symbol representation score at Time 1 and the type of kindergarten.