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Search Results: 1 - 10 of 120310 matches for " Yunfeng Wang "
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The Research of Event Detection and Characterization Technology of Ticket Gate in the Urban Rapid Rail Transit  [PDF]
Yunfeng Hou, Chaoli Wang, Yunfeng Ji
Journal of Software Engineering and Applications (JSEA) , 2015, DOI: 10.4236/jsea.2015.81002
Abstract: Making events recognition more reliable under complex environment is one of the most important challenges for the intelligent recognition system to the ticket gate in the urban rapid rail transit. The motion objects passing through the ticket gate could be described as a series of moving sequences got by sensors that located in the walkway side of the ticket gate. This paper presents a robust method to detect some classes of events of ticket gate in the urban rapid rail transit. Diffused reflectance infrared sensors are used to collect signals. In this paper, the motion objects are here referred to passenger(s) or (and) luggage(s), for which are of frequent occurrences in the ticket gate of the urban railway traffic. Specifically, this paper makes two main contributions: 1) The proposed recognition method could be used to identify several events, including the event of one person passing through the ticket gate, the event of two consecutive passengers passing through the ticket gate without a big gap between them, and the event of a passenger walking through the ticket gate pulling a suitcase; 2) The moving time sequence matrix is transformed into a one-dimensional vector as the feature descriptor. Deep learning (DL), back propagation neural network (BP), and support vector machine (SVM) are applied to recognize the events respectively. BP has been proved to have a higher recognition rate compared to other methods. In order to implement the three algorithms, a data set is built which includes 150 samples of all kinds of events from the practical tests. Experiments show the effectiveness of the proposed methods.
Improved Ladder Wave Modulation of Circulating Current Suppressing Control Strategy of MMC  [PDF]
Pinggang Song, Yunfeng Li, Lina Wang
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B223
Abstract: This paper partitions the arm current of MMC into uncontrollable current and controllable current. The former is determined by the load that can’t be controlled by taking any control strategy. The later caused by the unbalanced total inserted voltage of three arms can be controlled by some improved algorithms. The conclusion based on the researching the essence of circulating current is reached that change the number of the inserted sub-modules in each phase can suppress the circulating current. Combined with the improved ladder wave modulation, a novel circulating current suppression strategy particularly for the inverter station is developed. The improved strategy can adapt to load changes and reduce the circulating current and output voltage THD of MMC ac terminals greatly without increasing any peripheral circuits. Finally, the simulation model of 100 submodules in each phase is constructed in MATLAB and the simulation results verify the correctness and effectiveness of the modified control algorithm.
Radio Coverage Mapping in Wireless Sensor Networks  [PDF]
Yunfeng Nie, Chongyi Chen, Changsheng Wang
Wireless Sensor Network (WSN) , 2014, DOI: 10.4236/wsn.2014.610020
Abstract: Radio coverage directly affects the network connectivity, which is the foundational issue to ensure the normal operation of the network. Many efforts have been made to estimate the radio coverage of sensor nodes. The existing approaches (often RSSI measurement-based), however, suffer from heavy measurement cost and are not well suitable for the large-scale densely deployed WSNs. NRC-Map, a novel algorithm is put forward for sensor nodes radio coverage mapping. The algorithm is based on the RSSI values collected by the neighbor nodes. According to the spatial relationship, neighbor nodes are mapping to several overlapped sectors. By use of the least squares fitting method, a log-distance path loss model is established for each sector. Then, the max radius of each sector is computed according to the path loss model and the given signal attenuation threshold. Finally, all the sectors are overlapped to estimate the node radio coverage. Experimental results show that the method is simple and effectively improve the prediction accuracy of the sensor node radio coverage.
Sketch of Renewable Energy Production Simulation Platform  [PDF]
Jing Wang, Yunfeng Gao, Yuehui Huang, Yuefeng Wang, Jietan Zhang
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C010
Abstract:

Renewable Energy Production Simulation Platform (REPS) is developed by China Electric Power Research Institute (CEPRI) to simulate the operation of renewable energy in the power system. REPS takes into account the characteristics of China’s electric power system, it can assess the accommodation of renewable energy power and simulate the impact of different renewable energy capacity on the operation of power system. Assessment model and calculation process of REPS V1.3 is introduced in this article, and annual consumptive capacity in one provincial power grid of China is evaluated with the platform. REPS is of great guiding significance to electrical source planning. With the sustained and rapid growth of renewable energy in China, power system will be more and more dependent on REPS.

Studies on Enlightenment of China: Haier Group’s Transnational Operations to Chinese Enterprise
Yunfeng WANG,Jing SUN
Studies in Sociology of Science , 2012, DOI: 10.3968/j.sss.1923018420120302.1065
Abstract: After China joins World Trade Organization, enterprise carry on transnational operations is necessity; enterprise’s transnational operations are generally started from the export. Regarding the mature product, when after exporting develops certain stage, to follow the need of overseas market development, must carry on the comparison, by determined that which modes of business operation do serve the enterprise benefit. It must develop the transnational operations, the government should increase the support dynamics to the enterprise; The enterprise should raise own competitive advantage diligently; Speeds up the business management and the international trail connection step; Creates the new technology as circumstances permit; Pays special attention to the capital operation. Haier’s transnational operations have given Chinese Enterprise much enlightenment. Key words: Haier group; Transnational operations; Competitive; International
The Variational Assimilation Experiment of GPS Bending Angle
GPS折射角资料的变分同化试验

WANG Yunfeng,WANG Bin,
WANG Yunfeng
,WANG Bin

大气科学进展 , 2003,
Abstract: More and more new types of observational data provide many new opportunities for improving numericalweather forecasts. Among these, the GPS (Global Positioning System) bending angle is undoubtedly veryimportant. There are many advantages of the GPS bending angle, such as high resolution, availability inall weather conditions, and global data coverage. Thus it is very valuable to assimilate GPS bending angledata into numerical weather models. This paper introduces how to obtain and assimilate the GPS bendingangle. There are two methods of assimilation: the indirect method and direct method, and they are bothintroduced in this paper. During the minimizing process of variational assimilation, calculation efficiencyis very important and the optimal step size greatly influences the algorithm efficiency. Based on thecharacteristics of the minimizing algorithm, we obtain an adaptive method for calculating the optimizingstep suitable for all kinds of minimization algorithms through mathematical deduction. Finally, a numericalvariational assimilation experiment is performed using the GPS bending angle data of 11 October 1995.The numerical results indicate the validity of the variational assimilation method and the adaptive methodintroduced here.
CCR2 Regulates the Uptake of Bone Marrow-Derived Fibroblasts in Renal Fibrosis
Yunfeng Xia, Mark L. Entman, Yanlin Wang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077493
Abstract: Recent studies have shown that bone marrow-derived fibroblasts contribute significantly to the pathogenesis of renal fibrosis. However, the molecular mechanisms underlying the recruitment of bone marrow-derived fibroblasts into the kidney are incompletely understood. Bone marrow-derived fibroblasts express the chemokine receptor - CCR2. In this study, we tested the hypothesis that CCR2 participates in the recruitment of fibroblasts into the kidney during the development of renal fibrosis. Bone marrow-derived collagen-expressing GFP+ fibroblasts were detected in the obstructed kidneys of chimeric mice transplanted with donor bone marrow from collagen α1(I)-GFP reporter mice. These bone marrow-derived fibroblasts expressed PDGFR-β and CCR2. CCR2 knockout mice accumulated significantly fewer bone marrow-derived fibroblast precursors expressing the hematopoietic marker-CD45 and the mesenchymal markers-PDGFR-β or procollagen I in the obstructed kidneys compared with wild-type mice. Furthermore, CCR2 knockout mice displayed fewer bone marrow-derived myofibroblasts and expressed less α-SMA or FSP-1 in the obstructed kidneys compared with wild-type mice. Consistent with these findings, genetic deletion of CCR2 inhibited total collagen deposition and suppressed expression of collagen I and fibronectin. Moreover, genetic deletion of CCR2 inhibits MCP-1 and CXCL16 gene expression associated with a reduction of inflammatory cytokine expression and macrophage infiltration, suggesting a linear interaction between two chemokines/ligand receptors in tubular epithelial cells. Taken together, our results demonstrate that CCR2 signaling plays an important role in the pathogenesis of renal fibrosis through regulation of bone marrow-derived fibroblasts. These data suggest that inhibition of CCR2 signaling could constitute a novel therapeutic approach for fibrotic kidney disease.
Large-Scale Distributed Photovoltaic Power Dispatching and Operation Management Review  [PDF]
Nan Zhang, Yuefeng Wang, Yuehui Huang, Dewei Liu, Yunfeng Gao, Haifeng Li
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.34044
Abstract:

Distributed photovoltaic power (PV) is the main development model of distributed generation. It is necessary to research on dispatching and operation management with large-scale distributed PV connected. This paper analyzes development status, technical requirement and dispatching and operation management situation of distributed PV in Germany and China. Then introduce the preparation of distributed PV dispatching and operation management criterion. Through summarizing the experiences and lessons of large-scale distributed PV development in Germany, it gives advice to the development of distributed PV dispatching and operation management in China.

Research on Practical Teaching of Anatomy for Undergraduate Nursing Program under Information Technology Background in China  [PDF]
Yunfeng Wang, Wei Chen, Luqing Zhang, Lei Li, Lin Li, Zijian Ren, Kun Huang
Creative Education (CE) , 2019, DOI: 10.4236/ce.2019.104051
Abstract: Human anatomy is an important part of the foundation curriculum for undergraduate nursing program in China. Practical teaching of human anatomy plays a key role in consolidating the theoretical knowledge and cultivating students’ innovative spirit and practical abilities. With the development of information technology, the characteristics of the nursing specialties combined with information-based education need to be targeted in practical teaching of nursing anatomy. This paper describes a mode we have created for practical teaching, which combines the application of anatomical knowledge and clinical nursing skills in practical teaching; the improvements we have made to the nursing anatomy course are less rote learning, more independent learning, the provision of the online facilities for self-directed learning, the improvement in the quality of the practical laboratory facilities and the humanistic quality of the students’ education.These innovations will improve the quality and effectiveness of the nursing anatomy teaching, and promote the provision of high-quality practical personnel training for undergraduate nurses under information technology in China.
Evolution and frontogenesis of an imbalanced flow —the influence of vapor distribution and orographie forcing
Evolution and Frontogenesis of an Imbalanced Flow —the Influence of Vapor Distribution and Orographic Forcing

Wang Yunfeng,Wu Rongsheng,Pan Yinong,
Wang Yunfeng
,Wu Rongsheng,Pan Yinong

大气科学进展 , 2000,
Abstract: If the initial fields are not in geostrophic balance, the adjustment and evolution will occur in the stratified fluid, and the frontogenesis will occur under suitable conditions. The evolution is studied here with a nonhydrostatic fully compressible meso-scale model (Advanced Regional Prediction System, ARPS). Four cases are designed and compared: (i) control experiment; (ii) with different initial temperature gradient; (iii) with vapor distribution; (iv) with orographic forcing. The results show that: (1) there is an inertial oscillation in the evolution of the imbalanced flow with the frequency of the local Coriolis f, and with its amplitude de-creasing with time. The stationary balanced state can only be approached as it cannot be reached in the limit duration of time, The energy conversion ratio varies in the range of 0, 1 / 3]; (2) the stronger initial tempera-ture gradient can make the final energy conversion ratio higher, and vice versa; (3) suitable vapor distribu-tion is favorable for the frontogenesis. It will bring forward the time of the frontogenesis, strengthen the in-tensity of the cold front, and influence the final energy conversion ratio; (4) the orographic forcing has an ev-idently strengthening effect on the frontogenesis. The strengthening effect on the frontogenesis and the influ-ence on the final energy conversion ratio depend on the relative location of the mountain to the cold front.
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