Measurement of frequency characteristics of disturbance torque in the process of satellite antenna rotation

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1563-1569
Author(s):  
Bo Gao ◽  
Minglong Xu
Keyword(s):  
Real Time ◽  
Signal Transmission ◽  
Frequency Characteristics ◽  
Structural Vibration ◽  
Driving Mechanism ◽  
Satellite Antenna ◽  
Satellite Applications ◽  
Study Characteristics ◽  
Satellite Signal ◽  
Disturbance Torque

As an important equipment for satellite signal reception and transmission, the satellite antenna needs to be rotated in real time to achieve real-time tracking of the target and complete signal transmission during applications. Antenna driving mechanism is generally composed of motor and other components, which will cause some structural vibration during rotation. For high-stability satellite applications, the vibration disturbance torque is a major factor affecting the satellite stability. In order to study characteristics of the disturbance torque, the disturbance data from the antenna under different rotation conditions should be measured. In this paper, the frequency characteristics of disturbance torque of a rotating satellite antenna using stepper motor as driving motor is tested and discussed.

Use of real-time videoconferencing to deliver physical therapy services: A scoping review of published and emerging evidence

2019 ◽  
Vol 26 (10) ◽  
pp. 581-589 ◽  
Author(s):  
Stephanie Horsley ◽  
Gunnar Schock ◽  
Stacey L Grona ◽  
Kara Montieth ◽  
Bryttnee Mowat ◽  
...  
Keyword(s):  
Physical Therapy ◽  
Real Time ◽  
English Language ◽  
Data Extraction ◽  
Therapy Assessment ◽  
Process Outcomes ◽  
Study Characteristics ◽  
Therapy Services ◽  
Videoconferencing Technology ◽  
Physical Therapy Services

Introduction Telehealth may be a viable means to deliver physical therapy services across a range of practice settings and health conditions; however, there is limited uptake of telehealth in clinical practice. The purpose of this study is to examine and describe trends, gaps and opportunities in published and emerging evidence regarding the use of real-time videoconferencing to deliver physical therapy services. Methods Four databases and three trial registries were searched using terms for physical therapy and telehealth. Inclusion criteria were primary studies, systematic reviews and published trial registries that had the following features: physical therapy assessment and/or treatment, real-time videoconferencing and English language. Title/abstract, full text screening and data extraction were completed by pairs of independent reviewers. Descriptive statistics stratified by published research and trial registry records were used to summarize study characteristics. Results A total of 100 studies (80 published and 20 trial registries) were included. Australia, Canada and the US have the highest proportion of published and emerging research (63%). The majority of conditions studied were musculoskeletal (42%). Computers were the most common videoconferencing technology used (31%) and only 14% of studies reported using a secure platform. The majority of studies examined health outcomes (64%) and process outcomes (65%), while only 32% reported system outcomes. Discussion Research in the field of telehealth and physical therapy is growing and becoming increasingly diverse with the advancements in technology.

scholarly journals Groundwater Monitoring Systems to Understand Sea Water Intrusion Dynamics in the Mediterranean: The Neretva Valley and the Southern Venice Coastal Aquifers Case Studies

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 561
Author(s):  
Ivan Lovrinović ◽  
Alessandro Bergamasco ◽  
Veljko Srzić ◽  
Chiara Cavallina ◽  
Danko Holjević ◽  
...  
Keyword(s):  
Real Time ◽  
Coastal Aquifers ◽  
Sea Water ◽  
Quantitative Information ◽  
Water Dynamics ◽  
Monitoring Systems ◽  
Driving Mechanism ◽  
Sea Water Intrusion ◽  
Water Intrusion ◽  
Aquifer Systems

Sea water intrusion (SWI) has been widely recognized as a global problem, significantly influencing coastal aquifers, mostly through reduced water quality and agricultural production indicators. In this paper, we present the outcomes of the implementation of two independent real-time monitoring systems, planned and installed to get insights on groundwater dynamics within the adjacent coastal aquifer systems, one located in the Neretva Valley, southeastern Croatia, the other located south of the Venice lagoon, northeastern Italy. Both systems are presented with technical details and the capacity to observe, store, and transmit (Neretva site) observed values in real-time. Analysis of time series reveals the significant influence of the sea level oscillations onto the observed groundwater electrical conductivity (EC) and piezometric head values, while precipitation rate is detected as a driving mechanism for groundwater parameters in shallow geological units. The installed monitoring systems are shown to be of great importance to provide qualitative and quantitative information on the processes influencing groundwater and surface water dynamics within two coastal systems.

scholarly journals Real-time experimental demonstration of
low-cost VCSEL intensity-modulated 1125Gb/s optical OFDM signal transmission over 25km PON systems

2011 ◽  
Vol 19 (4) ◽  
pp. 2979 ◽  
Author(s):  
E. Hugues-Salas ◽  
R.P. Giddings ◽  
X.Q. Jin ◽  
J. L. Wei ◽  
X. Zheng ◽  
...  
Keyword(s):  
Real Time ◽  
Low Cost ◽  
Signal Transmission ◽  
Experimental Demonstration ◽  
Intensity Modulated ◽  
Ofdm Signal ◽  
Optical Ofdm

scholarly journals Applying innovative technologies for road surfaces monitoring

2021 ◽  
Vol 334 ◽  
pp. 01017
Author(s):  
Rustem Sakhapov ◽  
Marat Makhmutov
Keyword(s):  
Dielectric Constant ◽  
Signal Transmission ◽  
Frequency Characteristics ◽  
Repair Work ◽  
Innovative Technologies ◽  
Computer Equipment ◽  
Road Surfaces ◽  
Destructive Methods

The paper considers the advantages and nature of georadar monitoring of road surfaces comparing to traditional destructive methods of road exploration. The authors checked the thickness of the structural layers of pavement to determine appropriate repair work using the amplitude-frequency characteristics and the dielectric constant (the speed of signal transmission). The article examined the section of the highway and the examination data was recorded in a file, which allows further study and documentation of the material with the help of computer equipment.

Asynchronous Hard Real Time Signals Transmission in Embedded Networks

2014 ◽  
Vol 5 (4) ◽  
pp. 24-44 ◽  
Author(s):  
Liudmila Koblyakova ◽  
Yuriy Sheynin ◽  
Elena Suvorova
Keyword(s):  
Real Time ◽  
Signal Transmission ◽  
Aerospace Industry ◽  
Propagation Mechanism ◽  
Time Code ◽  
Embedded Networks ◽  
Control Information ◽  
Performance Requirements ◽  
Time Signals ◽  
Hard Real Time

Nowadays in the aerospace industry the router-based onboard embedded networks gradually replacing bus-based networks because they are already not satisfy the aerospace performance requirements. The SpaceWire, GigaSpaceWire and SpaceFibre standards are developing to meet the increasing aerospace requirements. The important requirement for any aerospace embedded onboard network is a transmission of control information and system signals in hard real time. These signals can be synchronous and asynchronous, periodic and aperiodic, with or without acknowledges. The distributed interrupt mechanism is used for asynchronous signal transmission and it is included into the second edition of SpaceWire standard. The Time-code propagation mechanism is used for synchronous signal transmission in SpaceWire. The broadcast messages mechanism is used for transmission of different system signal in SpaceFibre but it does not quite meet the requirements of hard real time. In this paper the authors consider the asynchronous signals transmission with and without acknowledges. The aims of this paper are following: 1) theoretically investigate the distributed interrupt mechanism; 2) to prove its properties; 3) to specify parameters and limitations; 4) to derive the time characteristics. For these purpose the authors developed the analytical model which describe the distributed interrupt propagation mechanism in terms of the graph theory.

Application Research of Intelligent Monitoring System Based on Abnormal Events

2015 ◽  
Vol 713-715 ◽  
pp. 471-474 ◽  
Author(s):  
Shuo Mei Wu ◽  
Jian Wei Song ◽  
Xu Ning Liu
Keyword(s):  
Real Time ◽  
Video Compression ◽  
Video Surveillance ◽  
New Technologies ◽  
Signal Transmission ◽  
Mobile Video ◽  
Information Industry ◽  
Application Research ◽  
Intelligent Monitoring ◽  
Smart Cameras

In order to meet the needs of the construction information industry base, enhance their ability to serve the community, and improve scientific research projects of market-oriented level, then develop family-oriented and school-based intelligent monitoring software system, the development of new products in the smart camera and mobile video surveillance and development of new technologies are developed. It is considered that the electronic information industry needs to develop intelligent monitoring technology industry, the video compression technology and the use of mobile and existing wireless networks are made, such as efforts are used to complete the smart cameras and mobile video surveillance system development, so the development of application research has implemented the front of video surveillance intelligence information collection, transmission of video signals in real time, real-time wireless video signal transmission and other tasks.

Research and Optimization on Media Access Control Delay of CAN

2012 ◽  
Vol 263-266 ◽  
pp. 1447-1452
Author(s):  
Hong Wei Zhang ◽  
Wen Juan Zhang ◽  
Xue Feng Han
Keyword(s):  
Access Control ◽  
Real Time ◽  
Signal Transmission ◽  
Influence Factors ◽  
Data Communication ◽  
Mathematical Expression ◽  
Media Access Control ◽  
Media Access ◽  
Control Delay ◽  
Transmission Period

With data quantity increasing dramatically and signal transmission period becoming more and more fast, the media access control delay has proved to be one of the main influence factors of CAN network real-time. Firstly, an equivalent numerical simulation model of CAN bus network is built to derivate the mathematical expression of media access control delay. Secondly, optimization measures are further proposed to improve the data communication real-time. At last, the optimization measures tested by experiments are proved to be correct and effective.

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