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Gan W, Su L, Chu Z. Trajectory Planning of Autonomous Underwater Vehicles Based on Gauss Pseudospectral Method. Sensors (Basel) 2023; 23:2350. [PMID: 36850948 PMCID: PMC9968012 DOI: 10.3390/s23042350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/15/2023] [Accepted: 02/18/2023] [Indexed: 06/18/2023]
Abstract
This paper aims to address the obstacle avoidance problem of autonomous underwater vehicles (AUVs) in complex environments by proposing a trajectory planning method based on the Gauss pseudospectral method (GPM). According to the kinematics and dynamics constraints, and the obstacle avoidance requirement in AUV navigation, a multi-constraint trajectory planning model is established. The model takes energy consumption and sailing time as optimization objectives. The optimal control problem is transformed into a nonlinear programming problem by the GPM. The trajectory satisfying the optimization objective can be obtained by solving the problem with a sequential quadratic programming (SQP) algorithm. For the optimization of calculation parameters, the cubic spline interpolation method is proposed to generate initial value. Finally, through comparison with the linear fitting method, the rapidity of the solution of the cubic spline interpolation method is verified. The simulation results show that the cubic spline interpolation method improves the operation performance by 49.35% compared with the linear fitting method, which verifies the effectiveness of the cubic spline interpolation method in solving the optimal control problem.
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Affiliation(s)
- Wenyang Gan
- Logistics Engineering College, Shanghai Maritime University, Shanghai 201306, China
| | - Lixia Su
- Logistics Engineering College, Shanghai Maritime University, Shanghai 201306, China
| | - Zhenzhong Chu
- School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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2
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Duan G, Su Y, Fu J. Landslide Displacement Prediction Based on Multivariate LSTM Model. Int J Environ Res Public Health 2023; 20:1167. [PMID: 36673921 PMCID: PMC9859347 DOI: 10.3390/ijerph20021167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/31/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
There are many frequent landslide areas in China, which badly affect local people. Since the 1980s, there have been more than 200 landslides in China with a death toll of 30 or more people at a time, economic losses of more than CNY 10 million or significant social impact. Therefore, the study of landslide displacement prediction is very important. The traditional ARIMA and LSTM models are commonly used for forecasting time series data. In our study, a multivariable LSTM landslide displacement prediction model is proposed based on the traditional LSTM model, which integrates rainfall and reservoir water level data. Taking the Baijiabao landslide in the Three Gorges Reservoir area as an example, the data of displacement, rainfall and reservoir water level of monitoring point ZG323 from November 2006 to December 2012 were selected for this study. Our results show that the displacement prediction results of the multivariable LSTM model are more accurate than those of the ARIMA and the univariate LSTM models, and the mean square, root mean square and mean absolute errors are the smallest, which are 0.64223, 0.8014 and 0.50453 mm, respectively. Therefore, the multivariable LSTM model method has higher accuracy and better application prospects in the displacement prediction of the Baijiabao landslide, which can provide a certain reference for the displacement prediction of the same type of landslide.
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Affiliation(s)
- Gonghao Duan
- School of Computer Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, China
- Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan 430074, China
- Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan 430074, China
| | - Yangwei Su
- School of Computer Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, China
- Hubei Provincial Key Laboratory of Intelligent Robot, Wuhan 430205, China
| | - Jie Fu
- Center For Hydrogeology and Environmental Geology Survey, China Geological Survey, Baoding 071051, China
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Pang Y, Liu H, Zhou C, Huang J, Gu H, Zhang Z. Pretreatment of Ultra-Weak Fiber Bragg Grating Hydrophone Array Based on Cubic Spline Interpolation Using Intensity Compensation. Sensors (Basel) 2022; 22:6814. [PMID: 36146165 PMCID: PMC9501917 DOI: 10.3390/s22186814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/03/2022] [Accepted: 07/06/2022] [Indexed: 06/16/2023]
Abstract
The demodulation algorithm based on 3 × 3 coupler in a fiber-optic hydrophone array has gained extensive attention in recent years. The traditional method uses a circulator to construct the normal path-match interferometry; however, the problem of increasing the asymmetry of the three-way signal to be demodulated is easily overlooked. To provide a solution, we report a pretreatment method for hydrophone array based on 3 × 3 coupler demodulation. We use cubic spline interpolation to perform nonlinear fitting to the reflected pulse train and calculate the peak-to-peak values of the single pulse to determine the light intensity compensation coefficient of the interference signal, so as to demodulate the corrected three-way interference signal. For experimental verification, ultra-weak fiber Bragg gratings (uwFBGs) with reflectivity of -50 dB are applied to construct a hydrophone array with 800 sensors, and a vibratory liquid column method is set up to generate a low-frequency hydroacoustic signal. Compared to the traditional demodulation algorithm based on a 3 × 3 coupler, the pretreatment method can improve the consistency of interference signals. The Lissajous figures show that cubic spline interpolation can improve the accuracy of monopulse peak seeking results by about 1 dB, and intensity compensation can further lead to a much lower noise density level for the interference pulse amplitude-specifically, more than 7 dB at 5~50 Hz-and the signal-to-noise ratio is improved by approximately 10 dB at 10 Hz. The distinct advantages of the proposed pretreatment method make it an excellent candidate for a hydrophone array system based on path-match interferometry.
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Affiliation(s)
- Yandong Pang
- Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China
| | - Hanjie Liu
- National Engineering Laboratory for Fiber Optic Sensor Technology, Wuhan University of Technology, Wuhan 430032, China
| | - Ciming Zhou
- National Engineering Laboratory for Fiber Optic Sensor Technology, Wuhan University of Technology, Wuhan 430032, China
| | - Junbin Huang
- Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China
| | - Hongcan Gu
- Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China
| | - Zhiqiang Zhang
- Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China
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Lin Q, Yao K, Zhao N, Jiao Y, Wang Z, Tian B, Zhao L, Peng G, Jiang Z. Finger Bending Sensing Based on Series-Connected Fiber Bragg Gratings. Materials (Basel) 2022; 15:ma15103472. [PMID: 35629500 PMCID: PMC9145747 DOI: 10.3390/ma15103472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/03/2022] [Accepted: 05/10/2022] [Indexed: 12/10/2022]
Abstract
Smart wearable devices are occupying an increasingly important position in scientific research and people's life fields. As an indispensable component of smart wearable devices, sensors play a crucial role in their sensing and feedback capabilities. In this paper, we investigate the bending gesture sensing for the most dexterous part of human anatomy, the finger. Based on series-connected fiber Bragg gratings (FBGs), recognition of finger bending posture is achieved by MATLAB modeling and the cubic spline interpolation.
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Affiliation(s)
- Qijing Lin
- Collaborative Innovation Center of High-End Manufacturing Equipment, Xi’an Jiaotong University, Xi’an 710049, China;
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
- School of Mechanical and Manufacturing Engineering, Xiamen Institute of Technology, Xiamen 361021, China
- Chongqing Key Laboratory of Micro-Nano Systems and Intelligent Sensing, Chongqing Academician Workstation, Chongqing 2011 Collaborative Innovation Center of Micro/Nano Sensing and Intelligent Ecological Internet of Things, Chongqing Technology and Business University, Chongqing 400067, China
| | - Kun Yao
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney 2052, Australia;
- Correspondence:
| | - Na Zhao
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
| | - Yunjing Jiao
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
| | - Zelin Wang
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
| | - Bian Tian
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
| | - Libo Zhao
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
| | - Gangding Peng
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney 2052, Australia;
| | - Zhuangde Jiang
- State Key Laboratory of Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (N.Z.); (Y.J.); (Z.W.); (B.T.); (L.Z.); (Z.J.)
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Zhou J, Ye J, Zhang X. [Development of Respiratory Signal Extraction System Based on Photoplethysmography]. Zhongguo Yi Liao Qi Xie Za Zhi 2021; 45:136-140. [PMID: 33825370 DOI: 10.3969/j.issn.1671-7104.2021.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oxygen saturation and respiratory signals are important physiological signals of human body, respiratory monitoring plays an important role in clinical and daily life. A system was established to extract respiratory signals from photoplethysmography in this study. Including the collection of pulse wave signal, the extraction of respiratory signal, and the calculation of respiratory rate and pulse rate transmitted from the slave computer to the host computer in real time.
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Affiliation(s)
- Jingjing Zhou
- School of Biomedical Engineering, Shenzhen University, Shenzhen, 518060
- Shenzhen Key Lab for Biomedical Engineering, Shenzhen, 518060
| | - Jilun Ye
- School of Biomedical Engineering, Shenzhen University, Shenzhen, 518060. E-mail:
- Shenzhen Key Lab for Biomedical Engineering, Shenzhen, 518060
- Guangdong Key Lab for Biomedical Measurements and Ultrasound Imaging, Shenzhen, 518060
| | - Xu Zhang
- School of Biomedical Engineering, Shenzhen University, Shenzhen, 518060
- Shenzhen Key Lab for Biomedical Engineering, Shenzhen, 518060
- Guangdong Key Lab for Biomedical Measurements and Ultrasound Imaging, Shenzhen, 518060
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George UZ, Moon KS, Lee SQ. Extraction and Analysis of Respiratory Motion Using a Comprehensive Wearable Health Monitoring System. Sensors (Basel) 2021; 21:1393. [PMID: 33671202 PMCID: PMC7923104 DOI: 10.3390/s21041393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 12/22/2022]
Abstract
Respiratory activity is an important vital sign of life that can indicate health status. Diseases such as bronchitis, emphysema, pneumonia and coronavirus cause respiratory disorders that affect the respiratory systems. Typically, the diagnosis of these diseases is facilitated by pulmonary auscultation using a stethoscope. We present a new attempt to develop a lightweight, comprehensive wearable sensor system to monitor respiration using a multi-sensor approach. We employed new wearable sensor technology using a novel integration of acoustics and biopotentials to monitor various vital signs on two volunteers. In this study, a new method to monitor lung function, such as respiration rate and tidal volume, is presented using the multi-sensor approach. Using the new sensor, we obtained lung sound, electrocardiogram (ECG), and electromyogram (EMG) measurements at the external intercostal muscles (EIM) and at the diaphragm during breathing cycles with 500 mL, 625 mL, 750 mL, 875 mL, and 1000 mL tidal volume. The tidal volumes were controlled with a spirometer. The duration of each breathing cycle was 8 s and was timed using a metronome. For each of the different tidal volumes, the EMG data was plotted against time and the area under the curve (AUC) was calculated. The AUC calculated from EMG data obtained at the diaphragm and EIM represent the expansion of the diaphragm and EIM respectively. AUC obtained from EMG data collected at the diaphragm had a lower variance between samples per tidal volume compared to those monitored at the EIM. Using cubic spline interpolation, we built a model for computing tidal volume from EMG data at the diaphragm. Our findings show that the new sensor can be used to measure respiration rate and variations thereof and holds potential to estimate tidal lung volume from EMG measurements obtained from the diaphragm.
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Affiliation(s)
- Uduak Z. George
- Department of Mathematics and Statistics, San Diego State University, San Diego, CA 92182, USA;
| | - Kee S. Moon
- Department of Mechanical Engineering, San Diego State University, San Diego, CA 92182, USA
| | - Sung Q. Lee
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea;
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Garner DM, Vanderlei FM, Valenti VE, Vanderlei LCM. Non-linear regulation of cardiac autonomic modulation in obese youths: interpolation of ultra-short time series. Cardiol Young 2019; 29:1196-201. [PMID: 31451125 DOI: 10.1017/S1047951119001951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND In this study, we applied ultra-short time series of interbeat intervals (RR-intervals) to evaluate heart rate variability through default chaotic global techniques with the purpose of discriminating obese youths from non-obese youth patients. METHOD Chaotic global analysis of the RR-intervals from the electrocardiogram and pre-processing adjustments was undertaken. The effect of cubic spline interpolations was assessed, while the spectral parameters remained fixed. Exactly, 125 RR-intervals of data were recorded. RESULTS CFP1, CFP3, and CFP6 were the only significant combinations of chaotic globals when the standard conditions were enforced and at the level p<0.01 (or <1%). These significances were acheived via Kruskal-Wallis and Cohen's ds effects sizes tests of significance after Anderson-Darling and Lilliefors statistical tests indicated non-normal distributions in the majority of cases. Adjustments of the cubic spline interpolation from 1 to 13 Hz were revealed to be inconsequential when measured by Kruskal-Wallis and Cohen's ds, regarding the outcome between the two datasets. CONCLUSION Chaotic global analysis was offered as a robust technique to distinguish autonomic dysfunction in obese youths. It can discriminate the two different groups using ultra-short data lengths, and no cubic spline interpolations need be applied.
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Wang W, Zheng B, Chen B, An Y, Jiang X, Li Z. [Research on Kalman interpolation prediction model based on micro-region PM2.5 concentration]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2018; 35:64-69. [PMID: 29745603 PMCID: PMC10307556 DOI: 10.7507/1001-5515.201609050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 11/03/2022]
Abstract
In recent years, the pollution problem of particulate matter, especially PM2.5, is becoming more and more serious, which has attracted many people's attention from all over the world. In this paper, a Kalman prediction model combined with cubic spline interpolation is proposed, which is applied to predict the concentration of PM2.5 in the micro-regional environment of campus, and to realize interpolation simulation diagram of concentration of PM2.5 and simulate the spatial distribution of PM2.5. The experiment data are based on the environmental information monitoring system which has been set up by our laboratory. And the predicted and actual values of PM2.5 concentration data have been checked by the way of Wilcoxon signed-rank test. We find that the value of bilateral progressive significance probability was 0.527, which is much greater than the significant level α = 0.05. The mean absolute error (MEA) of Kalman prediction model was 1.8 μg/m 3, the average relative error (MER) was 6%, and the correlation coefficient R was 0.87. Thus, the Kalman prediction model has a better effect on the prediction of concentration of PM2.5 than those of the back propagation (BP) prediction and support vector machine (SVM) prediction. In addition, with the combination of Kalman prediction model and the spline interpolation method, the spatial distribution and local pollution characteristics of PM2.5 can be simulated.
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Affiliation(s)
- Wei Wang
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, P.R.China
| | - Bin Zheng
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, P.R.China
| | - Binlin Chen
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, P.R.China
| | - Yaoming An
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, P.R.China
| | - Xiaoming Jiang
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, P.R.China
| | - Zhangyong Li
- Research Center of Biomedical Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065,
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Kiani MA, Sim KS, Nia ME, Tso CP. Signal-to-noise ratio enhancement on SEM images using a cubic spline interpolation with Savitzky-Golay filters and weighted least squares error. J Microsc 2015; 258:140-50. [PMID: 25676007 DOI: 10.1111/jmi.12227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 12/28/2014] [Indexed: 11/27/2022]
Abstract
A new technique based on cubic spline interpolation with Savitzky-Golay smoothing using weighted least squares error filter is enhanced for scanning electron microscope (SEM) images. A diversity of sample images is captured and the performance is found to be better when compared with the moving average and the standard median filters, with respect to eliminating noise. This technique can be implemented efficiently on real-time SEM images, with all mandatory data for processing obtained from a single image. Noise in images, and particularly in SEM images, are undesirable. A new noise reduction technique, based on cubic spline interpolation with Savitzky-Golay and weighted least squares error method, is developed. We apply the combined technique to single image signal-to-noise ratio estimation and noise reduction for SEM imaging system. This autocorrelation-based technique requires image details to be correlated over a few pixels, whereas the noise is assumed to be uncorrelated from pixel to pixel. The noise component is derived from the difference between the image autocorrelation at zero offset, and the estimation of the corresponding original autocorrelation. In the few test cases involving different images, the efficiency of the developed noise reduction filter is proved to be significantly better than those obtained from the other methods. Noise can be reduced efficiently with appropriate choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time.
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Affiliation(s)
- M A Kiani
- Faculty of Engineering and Technology, Multimedia University, Melaka, Malaysia
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