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Now showing items 1 - 16 of 158


    A media file placing method and device, storage medium and virtual reality apparatus. The method comprises: acquiring first location information of a viewing focus area of a target object in a virtual three-dimensional space for respective first predetermined time periods (S202); acquiring, in a second predetermined time period and according to the first location information, viewing distribution information of the target object in the virtual three-dimensional space (S204), wherein the second predetermined time period comprises the first predetermined time period; generating a target placement location in the virtual three-dimensional space according to the viewing distribution information (S206); and placing a media file at the target placement location in the virtual three-dimensional space (S208). The present solution addresses the technical problem in the art of low placement efficiency of a media file.
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  • Multi-Model Predictive Control with Kalman Filter on DC/DC Converter

    Zeng, Chen   Zhang, Li Yan   Zeng, Ling Hui  

    In this paper, a new kind of Multi-model Predictive Controller (MMPC) is presented. Multiple models switch MMPC with Kalman filter based on neural network optimization was implemented in a DC/DC converter. Multiple models direct switch was used according to the two modes of the Boost-Buck circuit and different loads condition. Kalman filter was successfully added to the MMPC to transfer the optimal state value to MMPC from the output of the DC/DC circuit. Parameters optimization method is also discussed in the paper when the controller was applied to real model simulation. Simulation result demonstrates that the good performance of MMPC compared with single model predictive control and PID control. With the help of high speed FPGA, it is possible to apply this method to hardware simulation.
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  • Predictive Control of DC/DC Converter Based on State Observer

    Zeng, Chen   Pan, Deng Min   Zhang, Li Yan  

    In this paper, we present an advanced way to control the DC/DC converter by using predictive control. As the current state of the circuit must be known while using the predictive control, state observer is applied to solve the problem that some variables of DC/DC converter can not be observed. Neural network optimization is used to solve the QP problems in single sample step of predictive control. Simulation results show that this approach can utilize fast converge property of neural network and the new control strategy turns out to be very efficiency.
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  • Spatially explicit assessment on urban vitality: Case studies in Chicago and Wuhan

    Zeng, Chen   Song, Yan   He, Qingsong   Shen, Feixue  

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  • Administrative restructuring and land-use intensity—A spatial explicit perspective

    Zeng, Chen   Zhang, Anlu   Liu, Lian   Liu, Yu  

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  • An ENVI+IDL+ArcEngine Tool for Detecting Harmful Algal Blooms in East China Sea

    Zeng, Chen   Xu, Hui Ping   Zhang, He Xia  

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  • Views on the Development of E-Commerce of Chinese Clothing Industry

    Zeng, Chen   Xu, Dong  

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    A control method and apparatus based on virtual reality. The method gives a prompt regarding a movable region to a first object by means of generating the movable region according to the movement request and the positions of other objects in a scene where the first object is located, so that the first object moves according to the prompt, thereby achieving the objective of the first object moving in the movable region of the scene. Since the movable region does not comprise security regions of the other objects in the scene, when moving in the movable region, the first object does not move to the security regions of the other objects in the scene, thereby achieving the technical effect that in a virtual reality system, the first object moves according to the positions of the other objects in the scene, and thus solving the technical problem that in the virtual reality system, due to the movement of the first object to the security regions of the other objects, the first object is too close to the other objects in the scene, such that the first object causes interference on the other objects.
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  • Monitoring and modeling urban expansion—A spatially explicit and multi-scale perspective

    Zeng, Chen   Zhang, Mengdi   Cui, Jiaxing   He, Sanwei  

    In the context of promoting new urbanization in China, urban expansion has been the subject of a consolidated line of research in the past two decades. In this study, we integrate remote sensing, a geographical information system, and spatial analysis techniques to monitor and model urban expansion with a spatially explicit and multi-scale perspective in Wuhan, the megacity in central China. We first extract urban built-up land from medium to high resolution images from 1995 to 2010 and analyze the expansion dynamics at the parcel level. For the exploration of the driving mechanisms underlying urban expansion, 20 explanatory variables are then categorized into three groups: characteristics, density, and proximity. A kernel window is then utilized to filter the extracted urban built-up land map at multiple scales. Moran's I is later used to test the spatial autocorrelation in the percentage of urban built-up land area and the residuals. Finally, a spatial lag model and a spatial error model are applied, to explore the causal factors of urban built-up land. It is revealed that the area of transportation land in Wuhan has increased tremendously, and urban built-up land is less scattered at the micro-scales. Regardless of the scale or model, housing density and gross domestic product (GDP) are positively correlated with the urban built-up land area, whereas the influence of other factors is shown to vary along with the scale or model. The results also confirm the superiority of the spatial regression models, and better fitting is produced with the increase in the scale. In the future, it is anticipated that the interpretation of remote sensing images and spatial analysis techniques will be optimized for better manifestation of intra-urban spatial interaction. In this process, the scale effect is an issue that should not be neglected in future studies of urban expansion. (C) 2014 Elsevier Ltd. All rights reserved.
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    A channel multiplexing method for reading array detector signals comprises: dividing array detectors into a number M of groups, at least two detectors being in each group; array coding the read channel to read a number M of row signals and a number N of column signals, which means when a signal is outputted at the detector in row a, column b, the signals of row a and column b are outputted correspondingly; connecting the readout signals of the row and the column to different positions of two transmission lines respectively; determining the source row number and column number of the signal on the basis of the time difference between the time of signal reaching two ends of the transmission line, and marking the source detector from which the signal is generated on the basis of two time differences of the row signal and the column signal. The method avoids the use of multiple electronic channels and thereby reduces the cost of electronic system and technical difficulty of implementation; meanwhile in the channel multiplexing process the use of the weighted resistor network is avoided, so that the replication of the multiplexed signal does not change greatly at different signal connecting points and the requirement of the dynamic range of the back-end readout circuit is lowered.
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  • Ecological Citizenship and Green Burial in China

    Zeng, Chen   Sweet, William   Cheng, Qian  

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    An array crystal module comprises a plurality of unit crystal strips (10). The exterior three-dimensional shape of the array crystal module is a frustum (12) or a combination of a right quadrangular prism (11) and the frustum (12), and the frustum (12) is used to be coupled with a photoelectric device (20). The frustum (12) comprises a first bottom face coupled with the photoelectric device (20) and a first top face opposed to the first bottom face, and the area of the first bottom face is smaller than that of the first top face. A fabrication method of the array crystal module includes: fabricating a crystal strip blank to obtain a unit crystal strip, performing the die cutting to obtain a unit crystal strip in the shape of a frustum or a unit crystal strip in the shape of a combination of a right quadrangular prism and a frustum according to a set obliquity and the thickness of the right quadrangular prism part, and assembling the unit crystal strips together to form an array crystal module. The above array crystal module, on the premise that the detection efficiency is guaranteed, can solve the problem of the light output loss of the crystal caused by the fact that the effective detection area of a photoelectric conversion device is smaller than a packaging area, thereby guaranteeing the sensitivity and performance of a detector.
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  • Management of urban land expansion in China through intensity assessment: A big data perspective

    Zeng, Chen   Yang, Ludi   Dong, Jianing  

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  • Application of polynomial algorithms to a random elastic medium

    Zeng, Chen   Leath, P.L.  

    A randomly pinned elastic medium in two dimensions is modeled by a disordered fully-packed loop model. The energetics of disorder-induced dislocations is studied using exact and polynomial algorithms from combinatorial optimization. Dislocations are found to become unbound at large scale, and the elastic phase is thus unstable giving evidence for the absence of a Bragg glass in two dimensions.
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  • Ground-State Roughness of the Disordered Substrate and Flux Lines in

    Zeng, Chen   Middleton, A. Alan   Shapir, Y.  

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  • Improving sediment load estimations: The case of the Yarlung Zangbo River (the upper Brahmaputra, Tibet Plateau)

    Zeng, Chen   Zhang, Fan   Lu, Xixi   Wang, Guanxing   Gong, Tongliang  

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