scholarly journals A Rapid Beam Pointing Determination and Beam-Pointing Error Analysis Method for a Geostationary Orbiting Microwave Radiometer Antenna in Consideration of Antenna Thermal Distortions

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5943
Author(s):  
Hualong Hu ◽  
Xiaochong Tong ◽  
He Li
Keyword(s):  
Real Time ◽  
Electromechanical Coupling ◽  
Microwave Radiometer ◽  
Computation Time ◽  
Optical Path ◽  
Microwave Antenna ◽  
Analysis Method ◽  
Pointing Error ◽  
Computing Method ◽  
The Ideal

When observing the Earth’s radiation signal with a geostationary orbiting (GEO) mechanically scanned microwave radiometer, it is necessary to correct the antenna beam pointing (ABP) in real time for the deviation caused by thermal distortions of antenna reflectors with the help of the on-board Image Navigation and Registration (INR) system during scanning of the Earth. The traditional ABP determination and beam-pointing error (BPE) analysis method is based on the electromechanical coupling principle, which usurps time and computing resources and thus cannot meet the requirement for frequent real-time on-board INR operations needed by the GEO microwave radiometer. For this reason, matrix optics (MO), which is widely used in characterizing the optical path of the visible/infrared sensor, is extended to this study so that it can be applied to model the equivalent optical path of the microwave antenna with a much more complicated configuration. Based on the extended MO method, the ideal ABP determination model and the model for determining the actual ABP affected by reflector thermal distortions are deduced for China’s future GEO radiometer, and an MO-based BPE computing method, which establishes a direct connection between the reflector thermal distortion errors (TDEs) and the thermally induced BPE, is defined. To verify the overall performance of the extended MO method for rapid ABP determination, the outputs from the ideal ABP determination model were compared to calculations from GRASP 10.3 software. The experimental results show that the MO-based ABP determination model can achieve the same results as GRASP software with a significant advantage in computational efficiency (e.g., at the lowest frequency band of 54 GHz, our MO-based model yielded a 4,730,000 times faster computation time than the GRASP software). After validating the correctness of the extended MO method, the impacts of the reflector TDEs on the BPE were quantified on a case-by-case basis with the help of the defined BPE computing method, and those TDEs that had a significant impact on the BPE were therefore identified. The methods and results presented in this study are expected to set the basis for the further development of on-board INR systems to be used in China’s future GEO microwave radiometer and benefit the ABP determination and BEP analysis of other antenna configurations to a certain extent.

scholarly journals A geometric approach for follow-the-leader motion of serpentine manipulator

2019 ◽  
Vol 16 (5) ◽  
pp. 172988141987463 ◽  
Author(s):  
Haibo Xie ◽  
Cheng Wang ◽  
Shusen Li ◽  
Liang Hu ◽  
Huayong Yang
Keyword(s):  
Path Planning ◽  
Real Time ◽  
Obstacle Avoidance ◽  
Degrees Of Freedom ◽  
Mechanical Design ◽  
Computation Time ◽  
Geometric Approach ◽  
Real Time Control ◽  
Time Control ◽  
The Ideal

This article presents a geometric approach for path planning of serpentine manipulator for real-time control in confined spaces. Firstly, the mechanical design of a serpentine manipulator is introduced, and its kinematics is analyzed. As the serpentine manipulator usually has more than 10 degrees of freedom, the motion control and obstacle avoidance are difficult considering its inverse kinematics. Follow-the-leader is an ideal path planning method for serpentine manipulator, as the manipulator moves forward, all the sections follow the path that the tip of manipulator has passed, which simplifies the obstacle avoidance. The realization of follow-the-leader method is to find the new configurations of the manipulator that can fit the ideal path with small errors. In this article, a novel geometric approach for follow-the-leader motion is proposed to solve new configurations with high precision of location and less computation time. The method is validated through simulation and the deviation from the ideal path is analyzed, simulation results show that calculation time for per step is less than 0.5 ms for a serpentine manipulator with 10 sections. To verify the follow-the-leader method, a 13-degree-of-freedom serpentine manipulator system with 6 sections was built, and 12 magnetic rotary encoders were embedded into the universal joints to collect data of rotation angles of each section. Experimental results show that the manipulator can carry out follow-the-leader motion as expected in real time.

scholarly journals Effect Analysis of the Digital Spectrometer FFT Algorithm on THz Atmospheric Limb Sounder (TALIS) System Sensitivity

2021 ◽  
Vol 13 (15) ◽  
pp. 2921
Author(s):  
Haowen Xu ◽  
Hao Lu ◽  
Zhenzhan Wang ◽  
Wenming He ◽  
Wenyu Wang
Keyword(s):  
Chemical Constituents ◽  
Microwave Radiometer ◽  
Mean Value ◽  
Integration Time ◽  
Science Center ◽  
Effect Analysis ◽  
System Sensitivity ◽  
Full Band ◽  
Digital Spectrometer ◽  
The Ideal

THz Atmospheric Limb Sounder (TALIS) is a microwave radiometer designed by the National Space Science Center of the Chinese Academy of Sciences (NSSC, CAS) for measuring the vertical distribution of temperature and chemical constituents in the middle and upper atmosphere. The digital spectrometer is an important part of TALIS’ back end, which mainly realizes the function of spectral analysis. The radix 16 real-time complex fast Fourier transform (FFT) algorithm used in the digital spectrometer was obtained by improving and combining the parallel processing and complex processing of the FFT algorithm. In this study, the digital spectrometer parameter selection is systematically presented, and the effect of the digital spectrometer FFT algorithm on the TALIS system sensitivity is analyzed based on the TALIS system simulation model we established in the previous stage of this research. The results show that the actual full-band sensitivity obtained after using the FFT algorithm is consistent with the ideal full-band sensitivity of TALIS for different integration time, spectral resolutions, and quantization bits. However, the results of the comparison of the actual sub-band sensitivity after using the FFT algorithm with the ideal sub-band sensitivity show that the deterioration of the sub-band sensitivity will be caused by the FFT algorithm. The mean value of the deterioration ratio was found to be approximately 18%, and the maximum value of the deterioration ratio was approximately 33%.

GIS Based Multi-Criteria decision support system and machine learning for Hospital Site Selection case study Oran - Algeria

2022 ◽  
Vol 14 (1) ◽  
pp. 0-0
Keyword(s):  
Site Selection ◽  
Decision Makers ◽  
Analysis Method ◽  
Automatic Learning ◽  
Hospital Site ◽  
Set Up ◽  
High Level ◽  
Selection Of ◽  
The Ideal

The selection of hospital sites is one of the most important choice a decision maker has to take so as to resist the pandemic. The decision may considerably affect the outbreak transmission in terms of efficiency , budget, etc. The main targeted objective of this study is to find the ideal location where to set up a hospital in the willaya of Oran Alg. For this reason, we have used a geographic information system coupled to the multi-criteria analysis method AHP in order to evaluate diverse criteria of physiological positioning , environmental and economical. Another objective of this study is to evaluate the advanced techniques of the automatic learning . the method of the random forest (RF) for the patterning of the hospital site selection in the willaya of Oran. The result of our study may be useful to decision makers to know the suitability of the sites as it provides a high level of confidence and consequently accelerate the power to control the COVID19 pandemic.

scholarly journals HiBuffer: Buffer Analysis of 10-Million-Scale Spatial Data in Real Time

2018 ◽  
Vol 7 (12) ◽  
pp. 467 ◽  
Author(s):  
Mengyu Ma ◽  
Ye Wu ◽  
Wenze Luo ◽  
Luo Chen ◽  
Jun Li ◽  
...  
Keyword(s):  
Real Time ◽  
Spatial Data ◽  
High Performance ◽  
Large Scale ◽  
Computation Time ◽  
Buffer Analysis ◽  
Data Volume ◽  
Time Buffer ◽  
Real World Datasets ◽  
Spatial Indexes

Buffer analysis, a fundamental function in a geographic information system (GIS), identifies areas by the surrounding geographic features within a given distance. Real-time buffer analysis for large-scale spatial data remains a challenging problem since the computational scales of conventional data-oriented methods expand rapidly with increasing data volume. In this paper, we introduce HiBuffer, a visualization-oriented model for real-time buffer analysis. An efficient buffer generation method is proposed which introduces spatial indexes and a corresponding query strategy. Buffer results are organized into a tile-pyramid structure to enable stepless zooming. Moreover, a fully optimized hybrid parallel processing architecture is proposed for the real-time buffer analysis of large-scale spatial data. Experiments using real-world datasets show that our approach can reduce computation time by up to several orders of magnitude while preserving superior visualization effects. Additional experiments were conducted to analyze the influence of spatial data density, buffer radius, and request rate on HiBuffer performance, and the results demonstrate the adaptability and stability of HiBuffer. The parallel scalability of HiBuffer was also tested, showing that HiBuffer achieves high performance of parallel acceleration. Experimental results verify that HiBuffer is capable of handling 10-million-scale data.

Fast Motion Estimation Algorithm Based on Real Time Monitoring

2011 ◽  
Vol 383-390 ◽  
pp. 5028-5033
Author(s):  
Xue Mei Xu ◽  
Qin Mo ◽  
Lan Ni ◽  
Qiao Yun Guo ◽  
An Li
Keyword(s):  
Motion Estimation ◽  
Real Time ◽  
Computation Time ◽  
Estimation Algorithm ◽  
Video Encoding ◽  
Experimental Result ◽  
Fast Motion Estimation ◽  
Motion Activity ◽  
Search Patterns ◽  
Motion Estimation Algorithm

In the video encoding system, motion estimation plays an important role at the front-end of encoder, which can eliminate inter redundancy efficiently and improve encoding efficiency. However, traditional motion estimation algorithm can’t be used in real-time application like video monitoring due to its computational complexity. In order to improve real-time efficiency, an improved motion estimation algorithm is proposed in this paper. The essential ideas consist of early termination rules, prediction of initial search point, and determination of motion type. Furthermore, our algorithm adopts different search patterns for certain motion activity. Experimental result shows that the improved algorithm reduces the computation time significantly while maintaining the image quality, and satisfies real time requirement in monitoring system.

scholarly journals Space-time clustering-based method to optimize shareability in real-time ride-sharing

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262499
Author(s):  
Negin Alisoltani ◽  
Mostafa Ameli ◽  
Mahdi Zargayouna ◽  
Ludovic Leclercq
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Computation Time ◽  
Clustering Method ◽  
Matching Problem ◽  
Solution Quality ◽  
Mobility Service ◽  
Ride Sharing ◽  
Large Scale Problems ◽  
Spatio Temporal

Real-time ride-sharing has become popular in recent years. However, the underlying optimization problem for this service is highly complex. One of the most critical challenges when solving the problem is solution quality and computation time, especially in large-scale problems where the number of received requests is huge. In this paper, we rely on an exact solving method to ensure the quality of the solution, while using AI-based techniques to limit the number of requests that we feed to the solver. More precisely, we propose a clustering method based on a new shareability function to put the most shareable trips inside separate clusters. Previous studies only consider Spatio-temporal dependencies to do clustering on the mobility service requests, which is not efficient in finding the shareable trips. Here, we define the shareability function to consider all the different sharing states for each pair of trips. Each cluster is then managed with a proposed heuristic framework in order to solve the matching problem inside each cluster. As the method favors sharing, we present the number of sharing constraints to allow the service to choose the number of shared trips. To validate our proposal, we employ the proposed method on the network of Lyon city in France, with half-million requests in the morning peak from 6 to 10 AM. The results demonstrate that the algorithm can provide high-quality solutions in a short time for large-scale problems. The proposed clustering method can also be used for different mobility service problems such as car-sharing, bike-sharing, etc.

scholarly journals EXPLORATION OF E-LEARNING VS TRADITIONAL LEARNING IN INDIA

2020 ◽  
Vol 8 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Gulbir Singh ◽  
Vivek Bhatnagar ◽  
Rajeev Gupta ◽  
Gautam Kumar
Keyword(s):  
Comparative Analysis ◽  
Real Time ◽  
Real Life ◽  
Research Data ◽  
University Education ◽  
Traditional Learning ◽  
Analysis Method ◽  
The Real ◽  
Huge Impact ◽  
E Learning

Purpose of Study: The purpose of the study is to carry out the comparison of traditional learning and e-learning with reference to university education. Methodology: A comparative analysis method that has been selected to fulfill the purpose of the study. The research data has been collected by various sources internet, previous research studies published in the Journal, universities which offer different technical and nontechnical programs .and further analyzed by in-depth understanding approach. Result: The outcome of this study will show the effect of e-learning in the current era. As we have compared e-learning with traditional learning and the result shows us that e-learning has filled the gap between the universities and the real-life industries' demands. Main finding: The result of this study showed that e-learning is the need of the present era in order to fulfill the gap between the universities and the real-life industries' demands. Additionally, e-learning based courses will have more impact and provide more skill and exposure to students as compared to traditional learning mode. Implications/Applications: This article can help the different universities and students to introduce more e-learning courses in their curriculum and they can fill the real-time industries' demands. Novelty/originality of the study: Our research can ensure that e-learning has a huge impact on our students and can help to increase the skills and exposure of them according to the current demands.

scholarly journals Content Analysis of Shariah-Compliant Investment Equity Funds in KSA: Does Social Justice Matter?

2020 ◽  
Vol 15 (6) ◽  
pp. 1 ◽  
Author(s):  
Khaled O. Alotaibi ◽  
Mohammad M. Hariri
Keyword(s):  
Social Justice ◽  
Saudi Arabia ◽  
Content Analysis ◽  
Analysis Method ◽  
Kingdom Of Saudi Arabia ◽  
Investment Funds ◽  
Content Analysis Method ◽  
Equity Funds ◽  
The Ideal

This paper examines the influence of capitalism and globalisation on the role of Shariah-Compliant Investment Funds (SCIFs) in promoting social justice in the Kingdom of Saudi Arabia (KSA) using content analysis method. This is to analyse the Terms and Conditions (T&C) of SCIFs as they appear in Tadawul (Saudi stock market) in 2019 and compared with the findings in 2013. This research critically evaluates the findings of the content analysis through aspects of globalization and insights from the literature review. The content analysis shows that SCIFs in KSA are disjointed and decoupled from Islamic principles and do not fulfil the ideal social justice role in society.

scholarly journals Real-time optical path difference compensation at the Plateau de Calern I2T interferometer

2001 ◽  
Vol 365 (2) ◽  
pp. 301-313 ◽  
Author(s):  
B. Sorrente ◽  
F. Cassaing ◽  
G. Rousset ◽  
S. RobbeDubois ◽  
Y. Rabbia
Keyword(s):  
Real Time ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path

Global Fixed Priority Scheduling with Constructing Execution Dependency in Multiprocessor Real-Time Systems

2018 ◽  
Vol 27 (10) ◽  
pp. 1850165
Author(s):  
Meiling Han ◽  
Tianyu Zhang ◽  
Yuhan Lin ◽  
Zhiwei Feng ◽  
Qingxu Deng
Keyword(s):  
Real Time ◽  
Real Time Systems ◽  
Analysis Method ◽  
Priority Scheduling ◽  
Fixed Priority ◽  
Fixed Priority Scheduling ◽  
Lower Priority ◽  
Acceptance Ratio ◽  
Processor Performance ◽  
Time Systems

The increasing demands for processor performance are driving system designers to adopt multiprocessors. In this paper, we study global fixed priority scheduling in multiprocessor real-time systems and introduce a technique for improving the schedulability. The key idea is to construct execution dependency for selected tasks to leverage slack time and reduce the interference between high-priority and low-priority tasks. Thus, more lower-priority tasks are enabled to be scheduled. Further, we provide a response time analysis method which takes the execution constraint of tasks into consideration. Extensive simulation results indicate that the proposed approach outperforms existing work in terms of acceptance ratio.

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