Three-dimensional fading channel models: A survey of elevation angle research

2014 ◽  
Vol 52 (6) ◽  
pp. 218-226 ◽  
Author(s):  
Jianhua Zhang ◽  
Chun Pan ◽  
Feng Pei ◽  
Guangyi Liu ◽  
Xiang Cheng
Keyword(s):  
Fading Channel ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Channel Models

scholarly journals Retrieving 3D Wind Field from Phased Array Radar Rapid Scans

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Xiaobin Qiu ◽  
Qin Xu ◽  
Chongjian Qiu ◽  
Kang Nai ◽  
Pengfei Zhang
Keyword(s):  
Wind Field ◽  
Adjoint Method ◽  
Phased Array ◽  
Elevation Angle ◽  
Three Dimensional ◽  
New Method ◽  
Horizontal Wind ◽  
Phased Array Radar ◽  
Temporal And Spatial ◽  
Vertical Winds

The previous two-dimensional simple adjoint method for retrieving horizontal wind field from a time sequence of single-Doppler scans of reflectivity and/or radial velocity is further developed into a new method to retrieve both horizontal and vertical winds at high temporal and spatial resolutions. This new method performs two steps. First, the horizontal wind field is retrieved on the conical surface at each tilt (elevation angle) of radar scan. Second, the vertical velocity field is retrieved in a vertical cross-section along the radar beam with the horizontal velocity given from the first step. The method is applied to phased array radar (PAR) rapid scans of the storm winds and reflectivity in a strong microburst event and is shown to be able to retrieve the three-dimensional wind field around a targeted downdraft within the storm that subsequently produced a damaging microburst. The method is computationally very efficient and can be used for real-time applications with PAR rapid scans.

Research on Total Error of Anti-Radiation Missile against Target Radiation Source Shutdown

2011 ◽  
Vol 63-64 ◽  
pp. 47-50
Author(s):  
Long Jie Zhang ◽  
Xiao Fang Xie ◽  
Jie Liang ◽  
De Dong Li ◽  
Jian Cao
Keyword(s):  
Navigation System ◽  
Radiation Source ◽  
Inertial Navigation System ◽  
Total Error ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Error Model ◽  
Location Error ◽  
Passive Location ◽  
Stationary Observer

This paper established the total error model of Anti-Radiation Missile under condition of target radiation source shutdown, which includes three dimensional passive location error model using information of azimuth and elevation angle as well as their changing rates, and gyroscope drift error model of Strap-down Inertial Navigation System. By analyzing the three dimensional passive location method to moving emitter using single stationary observer, the paper had a research to the hit probability of Anti-Radiation Missile under various flying conditions. If higher hit probability is required, the missile should increase its azimuth and elevation angle as much as possible while not to overstep its attack angle. Simulation result showed that the shutdown occasion of radiation source did much influence to the hit probability of Anti-Radiation Missile, which has great meaning to improve he bat efficiency of Anti-Radiation Missile.

Movement Coordination During Humeral Elevation in Individuals With Newly Acquired Spinal Cord Injury

2020 ◽  
Vol 36 (5) ◽  
pp. 345-350
Author(s):  
Margaret A. Finley ◽  
Elizabeth Euiler ◽  
Shivayogi V. Hiremath ◽  
Joseph Sarver
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Linear Relationship ◽  
Thoracic Kyphosis ◽  
External Rotation ◽  
Weight Bearing ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Movement Coordination ◽  
Cord Injury

Humeral elevation is a critical motion for individuals who use a manual wheelchair given that, in a typical day, wheelchair users reach overhead 5 times more often than able-bodied controls. Kinematic analyses in individuals with chronic spinal cord injury (SCI) have focused on weight-bearing tasks rather than overhead reaching. This technical report presents shoulder movement coordination during overhead reaching in individuals with newly acquired SCI. Eight volunteers with acute SCI and 8 matched, uninjured controls participated. Three-dimensional kinematics were collected during seated, humeral elevation. Scapular and thoracic rotations during humeral elevation were averaged across repetitions. The linear relationship of scapular upward rotation to humeral elevation provided movement coordination analysis. Maximal elevation was reduced in SCI with increased thoracic kyphosis. Medium to large effect sizes were found at each elevation angle, with reduced scapular external rotation, posterior tilt, and increased thoracic kyphosis for those with SCI. The linear relationship occurred later and within a significantly (P = .02) smaller range of humeral elevation in SCI. Altered movement coordination, including a diminished linear association of scapular upward rotation and humeral elevation (scapulohumeral rhythm), is found with reduced maximal elevation and increased thoracic kyphosis during overhead reaching tasks in those with acute SCI.

Weighted Spherical Sampling of Point Clouds for Forested Scenes

2020 ◽  
Vol 86 (10) ◽  
pp. 619-625 ◽  
Author(s):  
Alex Fafard ◽  
Ali Rouzbeh Kargar ◽  
Jan van Aardt
Keyword(s):  
Laser Scanning ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Sampling Bias ◽  
Volume Measurement ◽  
Stem Volume ◽  
Spherical Coordinate ◽  
Volume Assessment

Terrestrial laser scanning systems are characterized by a sampling pattern which varies in point density across the hemisphere. Additionally, close objects are over-sampled relative to objects that are farther away. These two effects compound to potentially bias the three-dimensional statistics of measured scenes. Previous methods of sampling have resulted in a loss of structural coherence. In this article, a method of sampling is proposed to optimally sample points while preserving the structure of a scene. Points are sampled along a spherical coordinate system, with probabilities modulated by elevation angle and squared distance from the origin. The proposed approach is validated through visual comparison and stem-volume assessment in a challenging mangrove forest in Micronesia. Compared to several well-known sampling techniques, the proposed approach reduces sampling bias and shows strong performance in stem-reconstruction measurement. The proposed sampling method matched or exceeded the stem-volume measurement accuracy across a variety of tested decimation levels. On average it achieved 3.0% higher accuracy at estimating stem volume than the closest competitor. This approach shows promise for improving the evaluation of terrestrial laser-scanning data in complex scenes.

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