Development of Adaptive Feed-Forward Cancellation With Frequency Estimation Algorithm for Compensation of Periodic Disturbance at Arbitrary Frequency

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Shota Yabui ◽  
Tsuyoshi Inoue
Keyword(s):  
Real Time ◽  
Frequency Estimation ◽  
Estimation Algorithm ◽  
Open Loop ◽  
Fixed Frequency ◽  
Nyquist Diagram ◽  
Feed Forward ◽  
Periodic Disturbance ◽  
Arbitrary Frequency ◽  
The Stability

Abstract In this study, an adaptive feed-forward cancellation (AFC) with frequency estimation algorithm has been developed to compensate for periodic disturbance at an arbitrary frequency. Conventional AFC was developed to compensate for periodic disturbance at a fixed frequency and cannot compensate for the disturbance in which the frequency varies in real-time. The proposed method can estimate the frequency of the disturbance in real-time by using the input and output signals of the AFC. It can compensate for the periodic disturbance at an arbitrary frequency. In addition, the stability of the feedback control system with the proposed AFC can be optimized at any frequency based on the vector locus of the open-loop characteristic on the Nyquist diagram. The effectiveness of the proposed AFC was confirmed in experiments compensating for whirling vibration, whose frequency varies in real-time in rotating machinery. The proposed AFC can estimate the frequency of the disturbance automatically and compensate for this adequately.

A Real-Time Transient Model of CF6 Turbofan Engine

2012 ◽  
Vol 241-244 ◽  
pp. 1573-1585 ◽  
Author(s):  
Hua Ting Yao ◽  
Xi Wang ◽  
Xiang Xing Kong
Keyword(s):  
Real Time ◽  
Nonlinear Equations ◽  
Volume Effect ◽  
Open Loop ◽  
Transient Model ◽  
Turbine Engine ◽  
Engine Model ◽  
Iterative Model ◽  
The Stability ◽  
Stability And Accuracy

In traditional aeroengine modeling, the nonlinear equations of engine model are generally solved through iterative algorithm. However, due to the strong nonlinear characteristics of the equations, the iterative model often fails to converge at some points of the full envelope and has a poor real time performance. In order to solve the problems, this paper proposes a non-iterative modeling method based on volume effect. In this method, several variables and differential equations of volume dynamics in aeroengine are introduced to the nonlinear equations, as a result, the whole set of equations becomes closed-form and can be solved without iteration. The non-iterative model of a gas turbine engine is written in matlab code. Furthermore, an open-loop simulation is carried out in matlab/simulink, both under groud and altitude condition. Meanwhile, the non-iterative model is verified by GSP11. The results illustrate that the non-iterative model provides good performance both in the stability and accuracy of solutions.

scholarly journals A Real-Time Harmonic Extraction Approach for Distorted Grid

Mathematics ◽  
2021 ◽  
Vol 9 (18) ◽  
pp. 2245
Author(s):  
Po Li ◽  
Xiang Li ◽  
Jinghui Li ◽  
Yimin You ◽  
Zhongqing Sang
Keyword(s):  
Power System ◽  
Real Time ◽  
Frequency Estimation ◽  
Harmonic Component ◽  
Estimation Algorithm ◽  
Phase Variable ◽  
Current Frequency ◽  
Zero Crossing ◽  
Grid Current ◽  
Harmonic Extraction

Harmonic interference is a major hazard in the current power system that affects power quality. How to extract harmonics quickly and accurately is the premise to ensure the sustainable operation of power system, which is particularly important in the field of new energy power generation. In this paper, a harmonic extraction method based on a time-varying observer is proposed. Firstly, a frequency estimation algorithm is used to estimate the power grid current frequency, which can estimate the frequency in real time. Then, applying the zero-crossing detection method to convert the frequency into a phase variable. Finally, using the phase variable and integral current signal as input, a observer is modeled to extract each order harmonic component. The proposed method is evaluated on a FGPA test platform, which shows that the method can extract the harmonic components of the grid current and converge within 80 ms even in the presence of grid distortions. In the verification case, the relative errors of the 1st, 5th, 7th and 11th harmonics are 0.005%, −0.003%, 0.251% and 0.620%, respectively, which are sufficiently small.

RPS24c Isoform Facilitates Tumor Angiogenesis Via Promoting the Stability of MVIH in Colorectal Cancer

2020 ◽  
Vol 20 (5) ◽  
pp. 388-395 ◽  
Author(s):  
Yue Wang ◽  
Youjun Wu ◽  
Kun Xiao ◽  
Yingjie Zhao ◽  
Gang Lv ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Ribosomal Protein ◽  
Real Time ◽  
Tumor Angiogenesis ◽  
Real Time Pcr ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Binding Interaction ◽  
Tubule Formation ◽  
The Stability

Background: Colorectal cancer (CRC) is the second leading cause of death worldwide, and distant metastasis is responsible for the poor prognosis in patients with advanced-stage CRC. RPS24 (ribosomal protein S24) as a ribosomal protein, multiple transcript variant encoding different isoforms have been found for this gene. Our previous studies have demonstrated that RPS24 is overexpressed in CRC. However, the mechanisms underlying the role of RPS24 in tumor development have not been fully defined. Methods: Expression of RPS24 isoforms and lncRNA MVIH in CRC tissues and cell lines were quantified by real-time PCR or western blotting assay. Endothelial tube formation assay was performed to determine the effect of RPS24 on tumor angiogenesis. The cell viability of HUVEC was determined by MTT assay, and the migration and invasion ability of HUVEC were detected by transwell assay. PGK1 secretion was tested with a specific ELISA kit. Results: Here, we found that RPS24c isoform was a major contributor to tumor angiogenesis, a vital process in tumor growth and metastasis. Real-time PCR revealed that RPS24c isoform was highly expressed in CRC tissues, while other isoforms are present in both normal and CRC tissues with no statistical difference. Moreover the change of RPS24 protein level is mainly due to the fluctuation of RPS24c. Furthermore, we observed that silencing RPS24c could decrease angiogenesis by inhibiting tubule formation, HUVEC cell proliferation and migration. Additionally, we investigated the molecular mechanisms and demonstrated that RPS24c mRNA interacted with lncRNA MVIH, the binding-interaction enhanced the stability of each other, thereby activated angiogenesis by inhibiting the secretion of PGK1. Conclusion: RPS24c facilitates tumor angiogenesis via the RPS24c/MVIH/PGK1 pathway in CRC. RPS24c inhibition may be a novel option for anti-vascular treatment in CRC.

scholarly journals A Prototype Quantitative Precipitation Estimation Algorithm for Operational S-Band Polarimetric Radar Utilizing Specific Attenuation and Specific Differential Phase. Part II: Performance Verification and Case Study Analysis

2019 ◽  
Vol 20 (5) ◽  
pp. 999-1014 ◽  
Author(s):  
Stephen B. Cocks ◽  
Lin Tang ◽  
Pengfei Zhang ◽  
Alexander Ryzhkov ◽  
Brian Kaney ◽  
...  
Keyword(s):  
Real Time ◽  
Heavy Precipitation ◽  
Estimation Algorithm ◽  
Differential Phase ◽  
Specific Attenuation ◽  
Quantitative Precipitation Estimation ◽  
Precipitation Estimation ◽  
Bias Ratio ◽  
Using Data ◽  
Precipitation Events

Abstract The quantitative precipitation estimate (QPE) algorithm developed and described in Part I was validated using data collected from 33 Weather Surveillance Radar 1988-Doppler (WSR-88D) radars on 37 calendar days east of the Rocky Mountains. A key physical parameter to the algorithm is the parameter alpha α, defined as the ratio of specific attenuation A to specific differential phase KDP. Examination of a significant sample of tropical and continental precipitation events indicated that α was sensitive to changes in drop size distribution and exhibited lower (higher) values when there were lower (higher) concentrations of larger (smaller) rain drops. As part of the performance assessment, the prototype algorithm generated QPEs utilizing a real-time estimated and a fixed α were created and evaluated. The results clearly indicated ~26% lower errors and a 26% better bias ratio with the QPE utilizing a real-time estimated α as opposed to using a fixed value as was done in previous studies. Comparisons between the QPE utilizing a real-time estimated α and the operational dual-polarization (dual-pol) QPE used on the WSR-88D radar network showed the former exhibited ~22% lower errors, 7% less bias, and 5% higher correlation coefficient when compared to quality controlled gauge totals. The new QPE also provided much better estimates for moderate to heavy precipitation events and performed better in regions of partial beam blockage than the operational dual-pol QPE.

scholarly journals Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song
Keyword(s):  
Sensor Networks ◽  
Real Time ◽  
Information Needs ◽  
Localization Algorithm ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Microseismic Events ◽  
The Stability ◽  
Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

scholarly journals Optimizations for identifying reference genes in bone and cartilage bioengineering

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Fei Xiong ◽  
Xiangyun Cheng ◽  
Chao Zhang ◽  
Roland Manfred Klar ◽  
Tao He
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Real Time ◽  
Reference Gene ◽  
Muscle Tissue ◽  
Reference Genes ◽  
Target Genes ◽  
The Stability ◽  
And Cartilage

Abstract Background Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) remains one of the best-established techniques to assess gene expression patterns. However, appropriate reference gene(s) selection remains a critical and challenging subject in which inappropriate reference gene selction can distort results leading to false interpretations. To date, mixed opinions still exist in how to choose the most optimal reference gene sets in accodrance to the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guideline. Therefore, the purpose of this study was to investigate which schemes were the most feasible for the identification of reference genes in a bone and cartilage bioengineering experimental setting. In this study, rat bone mesenchymal stem cells (rBMSCs), skeletal muscle tissue and adipose tissue were utilized, undergoing either chondrogenic or osteogenic induction, to investigate the optimal reference gene set identification scheme that would subsequently ensure stable and accurate interpretation of gene expression in bone and cartilage bioengineering. Results The stability and pairwise variance of eight candidate reference genes were analyzed using geNorm. The V0.15- vs. Vmin-based normalization scheme in rBMSCs had no significant effect on the eventual normalization of target genes. In terms of the muscle tissue, the results of the correlation of NF values between the V0.15 and Vmin schemes and the variance of target genes expression levels generated by these two schemes showed that different schemes do indeed have a significant effect on the eventual normalization of target genes. Three selection schemes were adopted in terms of the adipose tissue, including the three optimal reference genes (Opt3), V0.20 and Vmin schemes, and the analysis of NF values with eventual normalization of target genes showed that the different selection schemes also have a significant effect on the eventual normalization of target genes. Conclusions Based on these results, the proposed cut-off value of Vn/n + 1 under 0.15, according to the geNorm algorithm, should be considered with caution. For cell only experiments, at least rBMSCs, a Vn/n + 1 under 0.15 is sufficient in RT-qPCR studies. However, when using certain tissue types such as skeletal muscle and adipose tissue the minimum Vn/n + 1 should be used instead as this provides a far superior mode of generating accurate gene expression results. We thus recommended that when the stability and variation of a candidate reference genes in a specific study is unclear the minimum Vn/n + 1 should always be used as this ensures the best and most accurate gene expression value is achieved during RT-qPCR assays.

High-precision roll attitude estimation of decoupled canards relative to the projectile body using bipolar hall-effect sensors

2021 ◽  
pp. 1-9
Author(s):  
Tingting Yin ◽  
Zhong Yang ◽  
Youlong Wu ◽  
Fangxiu Jia
Keyword(s):  
Hall Effect ◽  
Real Time ◽  
High Precision ◽  
Solution Method ◽  
Estimation Method ◽  
Estimation Algorithm ◽  
Attitude Estimation ◽  
Fuzzy Algorithms ◽  
Positioning Method ◽  
Hall Effect Sensors

The high-precision roll attitude estimation of the decoupled canards relative to the projectile body based on the bipolar hall-effect sensors is proposed. Firstly, the basis engineering positioning method based on the edge detection is introduced. Secondly, the simplified dynamic relative roll model is established where the feature parameters are identified by fuzzy algorithms, while the high-precision real-time relative roll attitude estimation algorithm is proposed. Finally, the trajectory simulations and grounded experiments have been conducted to evaluate the advantages of the proposed method. The positioning error is compared with the engineering solution method, and it is proved that the proposed estimation method has the advantages of the high accuracy and good real-time performance.

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