The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform

Chunxi Zhang - One of the best experts on this subject based on the ideXlab platform.

  • High Precision Tri-Axial Quartz Flexible Accelerometers Resolution Measurement Method Based on Tri-Axial Turntable
    IEEE Access, 2020
    Co-Authors: Chunxi Zhang, Dai Minpeng
    Abstract:

    Aiming at the high requirements of the experimental equipment for the measurement of high precision quartz flexible accelerometer resolution, the gravity measured by high precision tri-axial accelerometers was subdivided by the tri-axial turntable. Tri-axial quartz flexible accelerometers resolution measurement model was established and general mathematical expression for the resolution measurement was derived. Based on the mathematical expression, the Effective Angle range that satisfied the measurement condition was given out. Besides, the tri-axial quartz flexible accelerometers resolution measurement process was designed. Within the Effective Angle range, numerical simulations were performed and the simulation results showed that: the proposed method can theoretically measure tri-axial quartz flexible accelerometers of which the resolution was about 10−6g. Then the tri-axial quartz flexible accelerometers resolution repetitive measurement experiments were carried out and the experimental results illustrated that: the difference between the measured value with the theoretical value is within $1~\mu \text{g}$ , which met the requirements for use. In addition, the resolution of tri-axial quartz flexible accelerometers can be measured at one time based on the designed process, demonstrating that the proposed method was valid.

  • High Precision Tri-Axial Quartz Flexible Accelerometers Resolution Measurement Method Based on Tri-Axial Turntable
    IEEE Access, 2020
    Co-Authors: Chunxi Zhang
    Abstract:

    Aiming at the high requirements of the experimental equipment for the measurement of high precision quartz flexible accelerometer resolution, the gravity measured by high precision tri-axial accelerometers was subdivided by the tri-axial turntable. Tri-axial quartz flexible accelerometers resolution measurement model was established and general mathematical expression for the resolution measurement was derived. Based on the mathematical expression, the Effective Angle range that satisfied the measurement condition was given out. Besides, the tri-axial quartz flexible accelerometers resolution measurement process was designed. Within the Effective Angle range, numerical simulations were performed and the simulation results showed that: the proposed method can theoretically measure tri-axial quartz flexible accelerometers of which the resolution was about 10-6g. Then the tri-axial quartz flexible accelerometers resolution repetitive measurement experiments were carried out and the experimental results illustrated that: the difference between the measured value with the theoretical value is within 1μ, which met the requirements for use. In addition, the resolution of tri-axial quartz flexible accelerometers can be measured at one time based on the designed process, demonstrating that the proposed method was valid.

Yen-da Chen - One of the best experts on this subject based on the ideXlab platform.

  • On Full-View Area Coverage by Rotatable Cameras in Wireless Camera Sensor Networks
    2017 IEEE 31st International Conference on Advanced Information Networking and Applications (AINA), 2017
    Co-Authors: Yang-pu Hsiao, Kuei-ping Shih, Yen-da Chen
    Abstract:

    The paper addresses an area coverage problem by using rotatable cameras in wireless camera sensor networks. It has been recognized as an important issue not only to Effectively cover an area of interest without holes but also to identify the object invaded the area by cameras in wireless camera sensor networks. Therefore, this paper presents a Full-View Area Coverage (FVAC) scheme to Effectively deploy rotatable camera sensors and tune their directions such that not only the area can be covered completely but also the object can be identified. In FVAC, the sizes of safe and unsafe regions with Effective Angle are derived. Moreover, a grid deployment model is investigated to deploy and rotate the camera sensors in accordance with the safe and unsafe regions in order not only to cover the area but also to identify the object. The grid size, that is, the distance among camera sensors, is also derived according to the Effective Angle and the sensing radius of camera sensors. Performance results show that the proposed scheme can reduce the number of deployed camera sensors and successfully identify objects against the related work in cases of a small Effective Angle or a short sensing radius.

  • AINA - On Full-View Area Coverage by Rotatable Cameras in Wireless Camera Sensor Networks
    2017 IEEE 31st International Conference on Advanced Information Networking and Applications (AINA), 2017
    Co-Authors: Yang-pu Hsiao, Kuei-ping Shih, Yen-da Chen
    Abstract:

    The paper addresses an area coverage problem by using rotatable cameras in wireless camera sensor networks. It has been recognized as an important issue not only to Effectively cover an area of interest without holes but also to identify the object invaded the area by cameras in wireless camera sensor networks. Therefore, this paper presents a Full-View Area Coverage (FVAC) scheme to Effectively deploy rotatable camera sensors and tune their directions such that not only the area can be covered completely but also the object can be identified. In FVAC, the sizes of safe and unsafe regions with Effective Angle are derived. Moreover, a grid deployment model is investigated to deploy and rotate the camera sensors in accordance with the safe and unsafe regions in order not only to cover the area but also to identify the object. The grid size, that is, the distance among camera sensors, is also derived according to the Effective Angle and the sensing radius of camera sensors. Performance results show that the proposed scheme can reduce the number of deployed camera sensors and successfully identify objects against the related work in cases of a small Effective Angle or a short sensing radius.

R Willingale - One of the best experts on this subject based on the ideXlab platform.

  • Effective collecting area of lobster eye optics and optimal value of Effective Angle
    Experimental Astronomy, 2019
    Co-Authors: V Tichý, M Barbera, R Hudec, R Willingale
    Abstract:

    Effective collecting area represents one of principal parameters of optical systems. The common requirement is to obtain as large Effective collecting area as it is possible. The paper presents an analytical method of calculating Effective collecting length and its maximization for lobster eye optics. The results are applicable for a Schmidt as well as for an Angel lobster eye geometry used in an astronomical telescope where the source is at infinity such that the incoming rays are parallel. The dependence of Effective collecting area vs. geometrical parameters is presented in a form of a simple compact equation. We show that the optimal ratio between mirrors depth and distance (Effective Angle) does not depend on other geometrical parameters and it is determined only by reflectivity function, i.e. by mirrors (or their coating) material and photon energy. The results can be also used for approximate but fast estimation of performance and for finding the initial point for consequent optimization by ray-tracing simulations.

Yang-pu Hsiao - One of the best experts on this subject based on the ideXlab platform.

  • On Full-View Area Coverage by Rotatable Cameras in Wireless Camera Sensor Networks
    2017 IEEE 31st International Conference on Advanced Information Networking and Applications (AINA), 2017
    Co-Authors: Yang-pu Hsiao, Kuei-ping Shih, Yen-da Chen
    Abstract:

    The paper addresses an area coverage problem by using rotatable cameras in wireless camera sensor networks. It has been recognized as an important issue not only to Effectively cover an area of interest without holes but also to identify the object invaded the area by cameras in wireless camera sensor networks. Therefore, this paper presents a Full-View Area Coverage (FVAC) scheme to Effectively deploy rotatable camera sensors and tune their directions such that not only the area can be covered completely but also the object can be identified. In FVAC, the sizes of safe and unsafe regions with Effective Angle are derived. Moreover, a grid deployment model is investigated to deploy and rotate the camera sensors in accordance with the safe and unsafe regions in order not only to cover the area but also to identify the object. The grid size, that is, the distance among camera sensors, is also derived according to the Effective Angle and the sensing radius of camera sensors. Performance results show that the proposed scheme can reduce the number of deployed camera sensors and successfully identify objects against the related work in cases of a small Effective Angle or a short sensing radius.

  • AINA - On Full-View Area Coverage by Rotatable Cameras in Wireless Camera Sensor Networks
    2017 IEEE 31st International Conference on Advanced Information Networking and Applications (AINA), 2017
    Co-Authors: Yang-pu Hsiao, Kuei-ping Shih, Yen-da Chen
    Abstract:

    The paper addresses an area coverage problem by using rotatable cameras in wireless camera sensor networks. It has been recognized as an important issue not only to Effectively cover an area of interest without holes but also to identify the object invaded the area by cameras in wireless camera sensor networks. Therefore, this paper presents a Full-View Area Coverage (FVAC) scheme to Effectively deploy rotatable camera sensors and tune their directions such that not only the area can be covered completely but also the object can be identified. In FVAC, the sizes of safe and unsafe regions with Effective Angle are derived. Moreover, a grid deployment model is investigated to deploy and rotate the camera sensors in accordance with the safe and unsafe regions in order not only to cover the area but also to identify the object. The grid size, that is, the distance among camera sensors, is also derived according to the Effective Angle and the sensing radius of camera sensors. Performance results show that the proposed scheme can reduce the number of deployed camera sensors and successfully identify objects against the related work in cases of a small Effective Angle or a short sensing radius.

Ki-Jung Kwon - One of the best experts on this subject based on the ideXlab platform.

  • Wind tunnel tests for a flapping wing model with a changeable camber using macro-fiber composite actuators
    Smart Materials and Structures, 2009
    Co-Authors: Dae-Kwan Kim, Jae-hung Han, Ki-Jung Kwon
    Abstract:

    In the present study, a biomimetic flexible flapping wing was developed on a real ornithopter scale by using macro-fiber composite (MFC) actuators. With the actuators, the maximum camber of the wing can be linearly changed from ?2.6% to +4.4% of the maximum chord length. Aerodynamic tests were carried out in a low-speed wind tunnel to investigate the aerodynamic characteristics, particularly the camber effect, the chordwise flexibility effect and the unsteady effect. Although the chordwise wing flexibility reduces the Effective Angle of attack, the maximum lift coefficient can be increased by the MFC actuators up to 24.4% in a static condition. Note also that the mean values of the perpendicular force coefficient rise to a value of considerably more than 3 in an unsteady aerodynamic flow region. Additionally, particle image velocimetry (PIV) tests were performed in static and dynamic test conditions to validate the flexibility and unsteady effects. The static PIV results confirm that the Effective Angle of attack is reduced by the coupling of the chordwise flexibility and the aerodynamic force, resulting in a delay in the stall phenomena. In contrast to the quasi-steady flow condition of a relatively high advance ratio, the unsteady aerodynamic effect due to a leading edge vortex can be found along the wing span in a low advance ratio region. The overall results show that the chordwise wing flexibility can produce a positive effect on flapping aerodynamic characteristics in quasi-steady and unsteady flow regions; thus, wing flexibility should be considered in the design of efficient flapping wings.