scholarly journals Real-Time Mode Switching and Beam Scanning of High-Gain OAM Waves Using a 1-Bit Reconfigurable Reflectarray Antenna

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2181
Author(s):  
Ziyang Wang ◽  
Xiaotian Pan ◽  
Fan Yang ◽  
Shenheng Xu ◽  
Maokun Li
Keyword(s):  
Real Time ◽  
Dimensional Space ◽  
Large Angle ◽  
High Gain ◽  
Mode Switching ◽  
Effective Control ◽  
Vortex Beam ◽  
Beam Scanning ◽  
The Future ◽  
Reflectarray Antenna

A reconfigurable electromagnetic surface has been studied to realize the adjustable orbital angular momentum (OAM) beams for real-time wireless communication and dynamic target detection in the future. OAM mode switching realized by many previous designs suffers from low gains without OAM beam scanning. In this article, a 1-bit reconfigurable reflectarray antenna is designed, fabricated, and tested for the real-time control of OAM mode switching and large-angle vortex beam scanning in three-dimensional space. The proposed reflectarray surface is composed of 1-bit electronically reconfigurable cells, and the size is 24 λ × 24 λ with 2304 units. The reconfigurable element is designed by using a radiation patch loading a PIN diode with effective control of two states, “ON” and “OFF”, for the demand of 180° phase difference. The reflectarray surface can be assigned to a code sequence of 0 or 1 by the Field-Programmable Gate Array (FPGA) in real time. Henceforth, the coding surface can dynamically control the generation of high-gain OAM beams, where only the optimized phase distributions on the surface need to be changed according to demand. To verify the concept, a large-scale reflectarray surface is fabricated and measured with an oblique feed at 15°. Different OAM-carrying phase distributions for different OAM beam states are calculated and tested. The test results show that the OAM mode switching between l = 1 and l = 2 is realized, and other variable modes such as l = 3 or l = 5 can also be achieved by modifying the phase encoding sequence. Furthermore, the direction of the vortex beams can be accurately controlled with gains over 20 dBi, and the large-angle vortex beam scanning is verified. Therefore, all results demonstrate that the proposed 1-bit reconfigurable reflectarray is efficient for the regulation and control of OAM-carrying beams for the demand of real-time dynamic wireless communications in the future.

The Design of a LED Illumination Control System Based on ARM, Infrared Technology and ZigBee

2013 ◽  
Vol 380-384 ◽  
pp. 384-387
Author(s):  
Min Li Yu ◽  
Yan Jun Bi ◽  
Ling Gang Meng
Keyword(s):  
Control System ◽  
Real Time ◽  
Effective Control ◽  
Infrared Sensor ◽  
Real Time Monitoring ◽  
The Core ◽  
Zigbee Technology ◽  
Infrared Technology ◽  
The Future

The design of a LED illumination control system based on ARM, infrared technology and ZigBee is described. With the core of S3C44B0X and the infrared sensor collecting the temperature information, the system uses ZigBee technology to do real time monitoring. Through the experiment, the system can make the safe, real time and effective control. It is meaning for the development of the future LED illumination.)

Design of a Bifocal Single Reflectarray Antenna with Improving Beam Scanning Performance

2015 ◽  
Vol 9 (1) ◽  
pp. 200-207
Author(s):  
Yan Qu ◽  
Chenjiang Guo ◽  
Wencan Peng ◽  
Jun Ding ◽  
Yuteng Gao ◽  
...  
Keyword(s):  
Side Lobe ◽  
High Gain ◽  
Field Of View ◽  
Circular Path ◽  
Side Lobe Level ◽  
Beam Scanning ◽  
Reflectarray Antenna ◽  
Gain Loss ◽  
Phase Design ◽  
Ku Band

A novel scheme is introduced to design the high gain beam scanning reflectarray antennas for limited scan range application. At first, various existing schemes for beam scanning reflectarray antennas design are reviewed and it is concluded that as a convenient design scheme, the feed displacement technique is preferred for limited scan range applications. In order to improve the scan range, a bifocal single reflector aperture phase is introduced for reflectarray aperture phase design, and in order to further improve the performance, a circular path for feed displacement is introduced to take the place of the conventional lateral path. Based on the introduced scheme, a Ku band bifocal single reflectarray antenna is designed for limited scan range application. The scan performances of the designed reflectarray are analyzed numerically and compared with conventional parabolic design. Numerical results show that the bifocal design shows significant improved scan performance with less 0.8 dB gain loss and lower than -13 dB side lobe level over entire scan range -30° to +30°, which illustrates that the bifocal design for limited field of view beam scanning reflectarray is a promising attempt.

Development and Application of Quality Control System for Highway Subgrade Construction

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Tong Wang
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Detection Method ◽  
System Development ◽  
Effective Control ◽  
Construction Process ◽  
Development Mode ◽  
The Road ◽  
Whole Process

The compaction quality of the subgrade is directly related to the service life of the road. Effective control of the subgrade construction process is the key to ensuring the compaction quality of the subgrade. Therefore, real-time, comprehensive, rapid and accurate prediction of construction compaction quality through informatization detection method is an important guarantee for speeding up construction progress and ensuring subgrade compaction quality. Based on the function of the system, this paper puts forward the principle of system development and the development mode used in system development, and displays the development system in real-time to achieve the whole process control of subgrade construction quality.

scholarly journals A palace fit for the future: Desirability in temporal work

2021 ◽  
pp. 147612702110120
Author(s):  
Siavash Alimadadi ◽  
Andrew Davies ◽  
Fredrik Tell
Keyword(s):  
Real Time ◽  
Crucial Role ◽  
The Past ◽  
Renewal Program ◽  
The Future ◽  
Depth Study ◽  
Future Events ◽  
Future Outcomes ◽  
Pluralistic Contexts

Research on the strategic organization of time often assumes that collective efforts are motivated by and oriented toward achieving desirable, although not necessarily well-defined, future states. In situations surrounded by uncertainty where work has to proceed urgently to avoid an impending disaster, however, temporal work is guided by engaging with both desirable and undesirable future outcomes. Drawing on a real-time, in-depth study of the inception of the Restoration and Renewal program of the Palace of Westminster, we investigate how organizational actors develop a strategy for an uncertain and highly contested future while safeguarding ongoing operations in the present and preserving the heritage of the past. Anticipation of undesirable future events played a crucial role in mobilizing collective efforts to move forward. We develop a model of future desirability in temporal work to identify how actors construct, link, and navigate interpretations of desirable and undesirable futures in their attempts to create a viable path of action. By conceptualizing temporal work based on the phenomenological quality of the future, we advance understanding of the strategic organization of time in pluralistic contexts characterized by uncertainty and urgency.

scholarly journals Molecular Survey of Vector-Borne Pathogens of Dogs and Cats in Two Regions of Saudi Arabia

Pathogens ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 25
Author(s):  
Abdullah D. Alanazi ◽  
Abdulaziz S. Alouffi ◽  
Mohamed S. Alyousif ◽  
Mohammad Y. Alshahrani ◽  
Hend H. A. M. Abdullah ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Real Time ◽  
Real Time Pcr ◽  
Bartonella Henselae ◽  
Public Awareness ◽  
Effective Control ◽  
Vector Borne Diseases ◽  
Babesia Vogeli ◽  
Vector Borne ◽  
First Time

Dogs and cats play an important role as reservoirs of vector-borne pathogens, yet reports of canine and feline vector-borne diseases in Saudi Arabia are scarce. Blood samples were collected from 188 free-roaming dogs and cats in Asir (70 dogs and 44 cats) and Riyadh (74 dogs), Saudi Arabia. The presence of Anaplasma spp., Bartonella spp., hemotropic Mycoplasma spp., Babesia spp., and Hepatozoon spp. was detected using a multiplex tandem real-time PCR. PCR-positive samples were further examined with specific conventional and real-time PCR followed by sequencing. Dogs from Riyadh tested negative for all pathogens, while 46 out of 70 dogs (65.7%) and 17 out of 44 cats (38.6%) from Asir were positive for at least one pathogen. Positive dogs were infected with Anaplasma platys (57.1%), Babesia vogeli (30%), Mycoplasma haemocanis (15.7%), and Bartonella henselae (1.4%), and cats were infected with Mycoplasma haemofelis (13.6%), Candidatus Mycoplasma haemominutum (13.6%), B. henselae (9.2%), and A. platys (2.27%), all of which are reported for the first time in Saudi Arabia. Co-infection with A. platys and B. vogeli was detected in 17 dogs (24.28%), while coinfections were not detected in cats. These results suggest that effective control and public awareness strategies for minimizing infection in animals are necessary.

scholarly journals Intuitive real-time control strategy for high-density myoelectric hand prosthesis using deep and transfer learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon Tam ◽  
Mounir Boukadoum ◽  
Alexandre Campeau-Lecours ◽  
Benoit Gosselin
Keyword(s):  
Real Time ◽  
Transfer Learning ◽  
Control Strategy ◽  
High Density ◽  
Fine Tuning ◽  
Mode Switching ◽  
Correct Prediction ◽  
Learning Approach ◽  
Predictive Values ◽  
Hand Prosthesis

AbstractMyoelectric hand prostheses offer a way for upper-limb amputees to recover gesture and prehensile abilities to ease rehabilitation and daily life activities. However, studies with prosthesis users found that a lack of intuitiveness and ease-of-use in the human-machine control interface are among the main driving factors in the low user acceptance of these devices. This paper proposes a highly intuitive, responsive and reliable real-time myoelectric hand prosthesis control strategy with an emphasis on the demonstration and report of real-time evaluation metrics. The presented solution leverages surface high-density electromyography (HD-EMG) and a convolutional neural network (CNN) to adapt itself to each unique user and his/her specific voluntary muscle contraction patterns. Furthermore, a transfer learning approach is presented to drastically reduce the training time and allow for easy installation and calibration processes. The CNN-based gesture recognition system was evaluated in real-time with a group of 12 able-bodied users. A real-time test for 6 classes/grip modes resulted in mean and median positive predictive values (PPV) of 93.43% and 100%, respectively. Each gesture state is instantly accessible from any other state, with no mode switching required for increased responsiveness and natural seamless control. The system is able to output a correct prediction within less than 116 ms latency. 100% PPV has been attained in many trials and is realistically achievable consistently with user practice and/or employing a thresholded majority vote inference. Using transfer learning, these results are achievable after a sensor installation, data recording and network training/fine-tuning routine taking less than 10 min to complete, a reduction of 89.4% in the setup time of the traditional, non-transfer learning approach.

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