The Experts below are selected from a list of 3888 Experts worldwide ranked by ideXlab platform

Vladimir Lipovac - One of the best experts on this subject based on the ideXlab platform.

  • projective approach in determining homogeneous hyperspherical geometrically based stochastic channel model s statistics Angle of Departure Angle of arrival and time of arrival
    IEEE Transactions on Wireless Communications, 2020
    Co-Authors: Almir Maric, Enio Kaljic, Pamela Njemcevic, Vladimir Lipovac
    Abstract:

    This article proposes geometrically-based stochastic channel model with scatterers homogeneously distributed within $N$ -dimensional ( $N$ -D) hyperspherical-shaped scattering region for single-bounce propagation scenario, with arbitrary positions of base station (BS) and mobile station (MS). For such defined geometrically-based stochastic channel model, the angular and temporal statistics are determined by introducing the projective approach. Accordingly, azimuthal Angle and time of arrival marginal PDFs are derived in closed form, while the elevation Angle PDF can be delivered numerically in general, and in closed-form for specific environmental parameters. The fidelity of the analytically obtained results is evaluated by their comparison to the corresponding normalized histograms. Also, it is shown that the proposed $N$ -D model can be used to analyze some of the existing channel models like 2-D uniform disk and 3-D uniform (hemi)sphere models. Additionally, by introducing the mentioned projective approach, it is shown that the angular statistics of the proposed $N$ -D model are the same as the angular statistics of some nonuniform 2-D and 3-D models, which is an important property of the proposed model. Such observation enabled us, for the first time in the literature, to determinate angular statistics for geometrically-based stochastic channel models such as inverted parabolic scattering model, 2-D Gaussian model and 3-D Gaussian hemisphere model, for arbitrary positions of BS and MS. Such angular characteristics of proposed channel model are validated through several empirical datasets.

Almir Maric - One of the best experts on this subject based on the ideXlab platform.

  • projective approach in determining homogeneous hyperspherical geometrically based stochastic channel model s statistics Angle of Departure Angle of arrival and time of arrival
    IEEE Transactions on Wireless Communications, 2020
    Co-Authors: Almir Maric, Enio Kaljic, Pamela Njemcevic, Vladimir Lipovac
    Abstract:

    This article proposes geometrically-based stochastic channel model with scatterers homogeneously distributed within $N$ -dimensional ( $N$ -D) hyperspherical-shaped scattering region for single-bounce propagation scenario, with arbitrary positions of base station (BS) and mobile station (MS). For such defined geometrically-based stochastic channel model, the angular and temporal statistics are determined by introducing the projective approach. Accordingly, azimuthal Angle and time of arrival marginal PDFs are derived in closed form, while the elevation Angle PDF can be delivered numerically in general, and in closed-form for specific environmental parameters. The fidelity of the analytically obtained results is evaluated by their comparison to the corresponding normalized histograms. Also, it is shown that the proposed $N$ -D model can be used to analyze some of the existing channel models like 2-D uniform disk and 3-D uniform (hemi)sphere models. Additionally, by introducing the mentioned projective approach, it is shown that the angular statistics of the proposed $N$ -D model are the same as the angular statistics of some nonuniform 2-D and 3-D models, which is an important property of the proposed model. Such observation enabled us, for the first time in the literature, to determinate angular statistics for geometrically-based stochastic channel models such as inverted parabolic scattering model, 2-D Gaussian model and 3-D Gaussian hemisphere model, for arbitrary positions of BS and MS. Such angular characteristics of proposed channel model are validated through several empirical datasets.

Jianxin Zhu - One of the best experts on this subject based on the ideXlab platform.

  • air curtain dust collecting technology a simulation study on air jet distribution and Departure Angle of air curtain generator
    Environmental Technology and Innovation, 2021
    Co-Authors: Yefeng Jiang, Zhenchang Fang, Xinli Zhao, Mingrui Zhang, Duolei Zhu, Jifeng Jia, Jianxin Zhu
    Abstract:

    Abstract The application of long air curtain generators in dust collection for hard-to-seal dust sources is in increasing demand, while the systematical investigation of their performance parameters is very topical. In this study, the FLUENT software package was used to simulate the effects of three structural parameters, namely the air supply groove length, air curtain diameter, and spacing between guide vanes, on the air curtain performance. The first two parameters were found to influence the air supply uniformity directly. Besides, the difference between internal and external pressures was related to the air curtain generator’s critical diameter with specific length: to ensure the required jet power of the air curtain, its actual diameter should exceed this critical value. The spacing adjustment between guide vanes could improve the air curtain skewness by changing the ratio of areas occupied by mechanically and nonmechanically deflected airflows, thereby enhancing the effective air supply length. Finally, the arc-shaped symmetrical guide vanes were shown to outperform folded asymmetrical guide vanes.

Zhenchang Fang - One of the best experts on this subject based on the ideXlab platform.

  • air curtain dust collecting technology a simulation study on air jet distribution and Departure Angle of air curtain generator
    Environmental Technology and Innovation, 2021
    Co-Authors: Yefeng Jiang, Zhenchang Fang, Xinli Zhao, Mingrui Zhang, Duolei Zhu, Jifeng Jia, Jianxin Zhu
    Abstract:

    Abstract The application of long air curtain generators in dust collection for hard-to-seal dust sources is in increasing demand, while the systematical investigation of their performance parameters is very topical. In this study, the FLUENT software package was used to simulate the effects of three structural parameters, namely the air supply groove length, air curtain diameter, and spacing between guide vanes, on the air curtain performance. The first two parameters were found to influence the air supply uniformity directly. Besides, the difference between internal and external pressures was related to the air curtain generator’s critical diameter with specific length: to ensure the required jet power of the air curtain, its actual diameter should exceed this critical value. The spacing adjustment between guide vanes could improve the air curtain skewness by changing the ratio of areas occupied by mechanically and nonmechanically deflected airflows, thereby enhancing the effective air supply length. Finally, the arc-shaped symmetrical guide vanes were shown to outperform folded asymmetrical guide vanes.

Liying Tan - One of the best experts on this subject based on the ideXlab platform.

  • research on the modification of Departure Angle detection for free space optical communications
    International Conference on Instrumentation and Measurement Computer Communication and Control, 2011
    Co-Authors: Shiqi Jiang, Liying Tan
    Abstract:

    Atmospheric turbulence leads to a stochastic process of optical intensity and phase of beam. Thus, errors of Departure Angle detection are induced. In the paper, a new method to modify of Departure Angle detection is introduced to Free Space Optical Communications. Based on the phase retrieval, the new method only needs the intensity of the image on the focal plane to calculate the revising phase. The complexity of the algorithm is reduced. The performance and its validity have been simulated in the paper. The results show that the errors of Departure Angle induced by the atmospheric turbulence become smaller.

  • Research on real time detection of Departure Angle for the laser beam through atmospheric channels
    Applied Optics, 2011
    Co-Authors: Jing Ma, Qingbo Yang, Shiqi Jiang, Siyuan Yu, Liying Tan, Qinglong Yang
    Abstract:

    The precision of Departure Angle detection for the laser beam can be improved by optimizing algorithms by which the high precision and stability of the laser beam pointing and tracking would be obtained, namely, improving the performance and accommodation of the free space optical communications. Atmospheric turbulence-induced optical intensity scintillations have a strong impact on the location precision of the laser spot through the atmospheric channels. Consequently, new requests come into view for the optimization of the algorithms. In the paper, the advantages and disadvantages of the traditional centroid method are analyzed. In terms of variations of laser spot, combined with the requests for real-time detection of Departure Angle, we proposed a new detection method. The edge of the laser spot on the detection sensor was redefined, and then the redefined spot was used to calculate the Departure Angle of the laser beam. The results of the simulations and experiments show that the precision of Departure Angle detection has been improved by more than 16%, which could reduce the effect of detection errors on the tracking procedure.