85 results on '"Hanqing Shi"'
Search Results
2. Rock breaking performance of the newly proposed unsubmerged cavitating abrasive waterjet
- Author
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Chenxing Fan, Haitao Zhang, Yong Kang, Hanqing Shi, and Deng Li
- Subjects
Rock breaking ,Abrasive waterjet ,Unsubmerged cavitation ,Erosion ,Specific energy consumption ,Mining engineering. Metallurgy ,TN1-997 - Abstract
To improve the rock breaking ability, cavitating waterjet and abrasive waterjet are combined by using a coaxial low-speed waterjet generated around the periphery of a high-speed abrasive waterjet, and a new type of waterjet called unsubmerged cavitating abrasive waterjet (UCAWJ) is thus produced. The rock breaking performance of UCAWJ was compared with submerged cavitating abrasive waterjet (SCAWJ) and unsubmerged abrasive waterjet (UAWJ) by impinging sandstone specimens. Moreover, the effects of jet pressure, standoff distance, abrasive flow rate and concentration were studied by evaluating the specific energy consumption, and the area, depth, and mass loss of the eroded specimen. The results show that the artificially generated submerged environment in UCAWJ is able to enhance the rock breaking performance under the same operating parameters. Furthermore, the rock breaking performance of UCAWJ is much better at higher jet pressures and smaller standoff distances when compared with UAWJ. The greatest rock breaking ability of UCAWJ appears at jet pressure of 50 MPa and standoff distance of 32 mm, with the mass loss of sandstone increased by 370.6% and the energy dissipation decreased by 75.8%. In addition, under the experimental conditions the optimal abrasive flow rate and concentration are 76.5 mL/min and 3%, respectively.
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- 2023
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3. A Long-Term Power Supply Risk Evaluation Method for China Regional Power System Based on Probabilistic Production Simulation
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Jianzu Hu, Yuefeng Wang, Fan Cheng, and Hanqing Shi
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long-term power supply risk ,power system transformation ,extreme weather ,probability evaluation ,probabilistic production simulation ,Technology - Abstract
To qualify the risk of extreme weather events for power supply security during the long-term power system transformation process, this paper proposes a risk probability evaluation method based on probabilistic production simulation. Firstly, the internal relationship of extreme weather intensity and duration is depicted using the copula function, and the influences of extreme weather on power security are described using the guaranteed power output ability coefficient, which can provide the extreme scenario basis for probabilistic production simulation. Then, a probabilistic production simulation method is proposed, which includes a typical-year scenario and extreme weather events. Meanwhile, an index system is proposed to qualify the power security level, which applies the loss of load expectation (LOLE) and time of loss of load expectation (TOLE) under different scenarios and other indices to reveal the long-term power security trend. Finally, the long-term power supply risks for the Yunnan provincial power system are analyzed using the proposed method, validating that the proposed method is capable of characterizing the influences of extreme weather on power security. The security level of different long-term power transformation schemes is evaluated.
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- 2024
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4. Characteristics of Oscillation in Cavity of Helmholtz Nozzle Generating Self-excited Pulsed Waterjet
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Miao Yuan, Deng Li, Yong Kang, Hanqing Shi, and Haizeng Pan
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Self-excited cavitation waterjet ,Flow-excited oscillations ,Frequency characteristics ,Vibration analysis ,Ocean engineering ,TC1501-1800 ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Abstract Cavity flow oscillations in the axisymmetric cavity are critical to the operating efficiency of self-excited pulsed waterjets, which are widely employed in many practical applications. In this study, the behaviors of a turbulent flow in axisymmetric cavities causing cavity flow oscillations are investigated based on wall pressure characteristics. Experiments are performed using four Helmholtz nozzles with varying length-to-radius ratios at flow velocities of 20–80 m/s. Three orders of hydrodynamic modes in axisymmetric cavity are obtained through the spectral analysis of wall pressure. Based on the experimental results, the empirical coefficient of Rossiter’s formula is modified, and the values of the parameter phase lag and the ratio of convection velocity to free stream velocity are obtained as 0.061 and 0.511, respectively. In addition, the spectral peak with a relatively constant frequency shows that the flow-acoustic resonance is excited significantly. A modified model is introduced based on the fluidic networks to predict the lock-on frequency. The results obtained can provide a basis for the structural optimization of the nozzle to improve the performance of self-excited pulsed waterjets.
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- 2022
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5. Non-Destructive Detection of Chicken Freshness Based on Electronic Nose Technology and Transfer Learning
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Yunwei Xiong, Yuhua Li, Chenyang Wang, Hanqing Shi, Sunyuan Wang, Cheng Yong, Yan Gong, Wentian Zhang, and Xiuguo Zou
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chicken freshness detection ,electronic nose ,transfer learning ,convolutional neural network ,Agriculture (General) ,S1-972 - Abstract
As a non-destructive detection method, an electronic nose can be used to assess the freshness of meats by collecting and analyzing their odor information. Deep learning can automatically extract features and uncover potential patterns in data, minimizing the influence of subjective factors such as selecting features artificially. A transfer-learning-based model was proposed for the electronic nose to detect the freshness of chicken breasts in this study. First, a 3D-printed electronic nose system is used to collect the odor data from chicken breast samples stored at 4 °C for 1–7 d. Then, three conversion to images methods are used to feed the recorded time series data into the convolutional neural network. Finally, the pre-trained AlexNet, GoogLeNet, and ResNet models are retrained in the last three layers while being compared to classic machine learning methods such as K Nearest Neighbors (KNN), Random Forest (RF), and Support Vector Machines (SVM). The final accuracy of ResNet is 99.70%, which is higher than the 94.33% correct rate of the popular machine learning model SVM. Therefore, the electronic nose combined with conversion to images shows great potential for using deep transfer learning methods for chicken freshness classification.
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- 2023
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6. A New Short-Term Prediction Method for Estimation of the Evaporation Duct Height
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Yanbo Mai, Zheng Sheng, Hanqing Shi, Chaolei Li, Qixiang Liao, and Jun Bao
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Evaporation duct ,nonlinear chaotic time series ,Darwinian evolutionary algorithm ,support vector regression ,back propagation neural network ,short-term prediction ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Evaporation duct is a kind of chaotic phenomenon over the ocean. In this paper, a new nonlinear prediction algorithm, the Darwinian evolutionary algorithm (DEA), is introduced to obtain the specific nonlinear formula P(·) of the chaotic phenomenon. Based on Darwinian natural selection and survival theory, the method first selects a suitable training set of samples, and then produces an initial population before going through an evolutionary process of selection, reproduction and mutation until the optimal individual is found. Finally, a specific expression for a nonlinear chaotic time series is obtained, which can realize the short-term prediction of evaporation duct height (EDH) quickly and accurately. After that, the DEA, the support vector regression (SVR), and the back propagation (BP) neural network were applied to predict the EDH which were formed over the ocean by using sounding data. After interpolation and smoothing of the original data, we selected the first 250 data as training samples and the last 115 data as test samples to test the effect of the EDA algorithm. The results showed that the root mean squared error (RMSE) for the DEA was about 7% less than that of the SVR and 10% less than that of BP neural network; the mean absolute percent error (MAPE) for the DEA was about 9% less than that of the SVR and 15% less than that of BP neural network. In addition, the DEA obtained, for the first time, a nonlinear expression for EDH, which provides an important reference for future research on the evaporation ducts.
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- 2020
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7. A New Estimation Algorithm for Frequency and Amplitude in Harmonic Signal Processing
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Yanbo Mai, Zheng Sheng, Hanqing Shi, Qixiang Liao, and Deli Liang
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Low-rank matrix recovery ,IALM ,improved strategy ,HR ,diagonal sparse matrix ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Low-rank matrix recovery is a large-scale data analysis and processing technology; its related theory has been widely used in image restoration, image denoising, video background modeling, signal recovery and other fields. This paper proposes an improved inexact augmented Lagrange multiplier (IALM) method to solve the harmonic recovery (HR) problem. After that, the performance of the original IALM and the improved IALM are compared when the sparse matrix is a diagonal sparse matrix satisfying certain conditions, and the results show that the improved IALM algorithm is more stable than the original algorithm. Then the improved strategy of the algorithm is extended to two kinds of occasions in which the positions of non-zero elements in sparse matrix are fixed or random, which provides a way to improve the algorithm in different application scenarios. Finally, the original IALM algorithm and the improved IALM algorithm are used to solve the HR problem, and the experimental results show that the improved IALM algorithm has better solution performance.
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- 2020
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8. Using Improved XGBoost Algorithm to Obtain Modified Atmospheric Refractive Index
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Yanbo Mai, Zheng Sheng, Hanqing Shi, and Qixiang Liao
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Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Cellular telephone services industry. Wireless telephone industry ,HE9713-9715 - Abstract
Atmospheric refraction is a special meteorological phenomenon mainly caused by gas molecules and aerosol particles in the atmosphere, which can change the propagation direction of electromagnetic waves in the atmospheric environment. Atmospheric refractive index, an index to measure atmospheric refraction, is an important parameter for electromagnetic wave. Given that it is difficult to obtain the atmospheric refractive index of 100 meters (m)–3000°m over the ocean, this paper proposes an improved extreme gradient boosting (XGBoost) algorithm based on comprehensive learning particle swarm optimization (CLPSO) operator to obtain them. Finally, the mean absolute percentage error (MAPE) and root mean-squared error (RMSE) are used as evaluation criteria to compare the prediction results of improved XGBoost algorithm with backpropagation (BP) neural network and traditional XGBoost algorithm. The results show that the MAPE and RMSE of the improved XGBoost algorithm are 39% less than those of BP neural network and 32% less than those of the traditional XGBoost. Besides, the improved XGBoost algorithm has the strongest learning and generalization capability to calculate missing values of atmospheric refractive index among the three algorithms. The results of this paper provide a new method to obtain atmospheric refractive index, which will be of great reference significance to further study the atmospheric refraction.
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- 2021
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9. Optimal Interpolation Model for Synthetic Aperture Radar Wind Retrieval
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Wei Zhang, Zhuhui Jiang, Jie Xiang, and Hanqing Shi
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synthetic aperture radar ,sea surface wind ,optimal interpolation ,variational model inversion ,C-band model direct wind retrieval ,Science - Abstract
The variational model inversion (VAR) method for synthetic aperture radar (SAR) wind retrieval based on the Bayesian theory can overcome the limitations of the traditional wind streak algorithm by introducing background wind and considering all sources of error, but its optimal solution is unstable and the time latency is long. In this article, we propose a new wind retrieval method by applying the optimal interpolation (OI) theory to construct a formula that considers the SAR information, background information coming from the numerical prediction model, and their associated well-characterized errors. The retrieved wind vector can be acquired by the analytic solution of the OI formula. The results from the simulation data show that the error of the OI-retrieved wind is smaller than that of background wind in all considered cases; in particular, the accuracy of the OI-retrieved wind speed is significantly improved. Experiments on the Sentinel-1 SAR data show that the root mean square error of the OI-retrieved wind speed and direction are 1.4 m/s and 35°, respectively. Compared with other methods, the retrieved wind speed accuracy of the OI method is similar to that of the VAR method but higher than that of the direct wind retrieval method. The time latency of the OI method is the shortest, and the calculation efficiency is much higher than that of the VAR method. The results indicate that the OI method can be effectively applied to SAR wind retrieval.
- Published
- 2020
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10. Experimental Investigation on the Characteristic of Hydrodynamic-Acoustic Cavitation (HAC)
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Miao Yuan, Yong Kang, Hanqing Shi, Dezheng Li, and Hongchao Li
- Subjects
Hydrodynamic-Acoustic Cavitation (HAC) ,high-speed photography ,cavitation dynamics ,The Proper Orthogonal Decomposition method (POD) ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
This study aimed to investigate the Cavitation dynamics of Hydrodynamic-acoustic cavitation by employing experimental methods. The spatial distribution of cavitation clouds, the temporal and spatial distribution achieved by cavitation clouds, and the main flow structure in the flow field were extracted and analyzed by complying with the cavitating flow image captured with the high-speed camera. As indicated from the results, the widened cavitation region and the strength of cavitation under the synergy of ultrasound were reported. When the inlet pressure is 2 MPa, the average value of the volume-averaging cavitation intensity variable is 0.029, 0.058, and 0.092, respectively, and the corresponding growth rate is 95% and 58.5%. By adopting the Proper Orthogonal Decomposition method (POD), the ultrasound was revealed to primarily enhance the cavitation intensity by downregulating the cavitation threshold other than altering the large-scale vortex structure in the flow field. The high-frequency pressure pulsation of ultrasound strengthened the instability exhibited by the shear layer and induced small-scale vortex structures at the shear layer, which was suggested to be the more violently shed and collapse.
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- 2022
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11. A New Diagnostic Model and Improved Prediction Algorithm for the Heights of Evaporation Ducts
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Yanbo Mai, Zheng Sheng, Hanqing Shi, Chaolei Li, Lihang Liu, Qixiang Liao, Wei Zhang, and Shudao Zhou
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evaporation duct heights ,new diagnostic height model ,AR algorithm ,improved SVR algorithm ,time series ,Science - Abstract
This paper develops a new method for the diagnosis and prediction of the evaporation duct heights on the sea, which has certain reference significance for the study of the evaporation ducts. Based on traditional diagnostic and predictive models of evaporation duct heights, a new diagnostic model is proposed. By determining the overall Richardson number Rib, the Monin-Obukhov (M-O) length L and the wind speed characteristic parameter u∗, temperature characteristic parameter θ∗ and humidity characteristic parameters q∗ are calculated, and then the evaporation duct height is diagnosed. Taking the diagnosed heights as a time series, and using the support vector regression (SVR) algorithm improved by a simulated annealing operator, then the time series is analyzed by taking three consecutive sample steps as input and the next sample step as output in order to develop an algorithm for predicting future heights. Finally, the prediction results are compared with those from the traditional auto-regressive (AR) algorithm and classical SVR algorithm to identify the advantages and disadvantages of the improved SVR algorithm. The results show that the root-mean-square error (RMSE) of the traditional AR, the classical SVR and the improved SVR algorithms is 0.60, 0.45, and 0.38, and the mean absolute percentage error (MAPE) of the three algorithms is 7.79%, 6.10% and 4.78%, respectively. The prediction error of the improved SVR algorithm is 37% less than that of the traditional AR algorithm and 15% less than that of the classical SVR algorithm, signifying an improvement in its prediction capability.
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- 2020
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12. Spatiotemporal Distribution of Atmospheric Ducts in Alaska and Its Relationship with the Arctic Vortex
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Yanbo Mai, Zheng Sheng, Hanqing Shi, Qixiang Liao, and Wei Zhang
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Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Cellular telephone services industry. Wireless telephone industry ,HE9713-9715 - Abstract
In this paper, global position system high-resolution sounding data from 1998 to 2008 were used to statistically analyze the spatiotemporal distribution and determine the probability, thickness, and intensity of atmospheric ducts at 12 stations in Alaska. In addition, the singular value decomposition (SVD) was used to examine the relationship between the Arctic vortex and atmospheric ducts. The annual average probability of atmospheric ducts, primarily surface and elevation ducts, was approximately 30% in Alaska. The probability of elevation ducts was greater than that of surface ducts. The Arctic vortex area and intensity index of each subarea were significantly negatively correlated with the occurrence of atmospheric ducts. Thus, when the area of the Arctic vortex increased and the intensity index of each subarea strengthened, the probability of atmospheric ducts decreased and their characteristics weakened.
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- 2020
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13. Using the Decomposition-Based Multi-Objective Evolutionary Algorithm with Adaptive Neighborhood Sizes and Dynamic Constraint Strategies to Retrieve Atmospheric Ducts
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Yanbo Mai, Hanqing Shi, Qixiang Liao, Zheng Sheng, Shuai Zhao, Qingjian Ni, and Wei Zhang
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special sensor ,GNSS ,new algorithm ,balance the diversity and convergence of the population ,atmospheric ducts ,Chemical technology ,TP1-1185 - Abstract
The traditional method of retrieving atmospheric ducts is to use the special sensor of weather balloons or rocket soundings to obtain information intelligently, and it is very expensive. Today, with the development of technology, it is very convenient to retrieve the atmospheric ducts from Global Navigation Satellite System (GNSS) phase delay and propagation loss observation data, and then the GNSS receiver on the ground forms an automatic receiving sensor. This paper proposes a hybrid decomposition-based multi-objective evolutionary algorithm with adaptive neighborhood sizes (EN-MOEA/ACD-NS), which dynamically imposes some constraints on the objectives. The decomposition-based multi-objective evolutionary algorithm (MOEA/D) updates the solutions through neighboring objectives, the number of which affects the quality of the optimal solution. Properly constraining the optimization objectives can effectively balance the diversity and convergence of the population. The experimental results from the Congress on Evolutionary Computation (CEC) 2009 on test instances with hypervolume (HV), inverted generational distance (IGD), and average Hausdorff distance ∆2 metrics show that the new method performs similarly to the evolutionary algorithm MOEA/ACD-NS, which considers only the dynamic change of the neighborhood sizes. The improved algorithm is applied to the practical problem of jointly retrieving atmospheric ducts with GNSS signals, and its performance further demonstrates its feasibility and practicability.
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- 2020
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14. A Comparative Study on Evolutionary Multi-objective Optimization Algorithms Estimating Surface Duct
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Qixiang Liao, Zheng Sheng, Hanqing Shi, Lei Zhang, Lesong Zhou, Wei Ge, and Zhiyong Long
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multi-objective optimization algorithm ,atmospheric duct ,GPS, hypervolume ,inverted generational distance ,Chemical technology ,TP1-1185 - Abstract
The problem of atmospheric duct inversion is usually solved as a single objective optimization problem. Based on ground-based Global Positioning System (GPS) phase delay and propagation loss, this paper develops a multi-objective method including the effect of source frequency and receiving antenna height. The diversity and convergence of solution sets are evaluated for seven multi-objective evolutionary algorithms with three performance metrics: Hypervolume (HV), Inverted Generational Distance (IGD), and the averaged Hausdorff distance ( Δ 2 ). The inversion results are compared with the simulation results, and the experimental comparison is conducted on three groups of test situations. The results demonstrate that the ranking of algorithm performance varies because of the different methods used to calculate performance metrics. Moreover, when the algorithms show overwhelming performance using performance metrics, the inversion result is not more close to the real value. In the comparison of computational experiments, it was found that, as the retrieved parameter dimension increases, the inversion result becomes more unstable. When the observed data are sufficient, the inversion result seems to be improved.
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- 2018
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15. Estimation of Surface Duct Using Ground-Based GPS Phase Delay and Propagation Loss
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Qixiang Liao, Zheng Sheng, Hanqing Shi, Jie Xiang, and Hong Yu
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surface duct ,refractivity structure ,GPS ,remote sensing ,NSGA-II ,matched-field processing ,Science - Abstract
The propagation of Global Positioning System (GPS) signals at low-elevation angles is significantly affected by a surface duct. In this paper, we present an improved algorithm known as NSSAGA, in which simulated annealing (SA) is combined with the non-dominated sorting genetic algorithm II (NSGA-II). Matched-field processing was used to remotely sense the refractivity structure by using the data of ground-based GPS phase delay and propagation loss from multiple antenna heights. The performance was checked by simulation data with and without noise. In comparison with NSGA-II, the new hybrid algorithm retrieved the refractivity structure more efficiently under various noise conditions. We then modified the objective function and found that matched-field processing is more effective than the conventional least-squares method for inferring the refractivity parameters. Comparing the inversion results and in situ sounding data suggests that the improved method presented herein can capture refractivity characteristics in realistic environments.
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- 2018
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16. Comparison of Wind Speeds from Spaceborne Microwave Radiometers with In Situ Observations and ECMWF Data over the Global Ocean
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Lei Zhang, Hanqing Shi, Zhenzhan Wang, Hong Yu, Xiaobin Yin, and Qixiang Liao
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microwave radiometer ,wind speed ,remote sensing ,ECMWF ,validation ,Science - Abstract
This study compares wind speeds derived from five satellite microwave radiometers with those directly observed by buoy-mounted anemometers and the global analyses produced by the European Center for Medium-Range Weather Forecasts (ECMWF) model. Buoy comparisons yield wind speed root mean square errors of 0.82 m/s for WindSat, 1.45 m/s for SSMIS F16, 1.39 m/s for SSMIS F17, 1.43 m/s for AMSR-E, and 1.45 m/s for AMSR2. The overall mean bias for each satellite is typically
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- 2018
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17. An Integrated Convective Cloud Detection Method Using FY-2 VISSR Data
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Kuai Liang, Hanqing Shi, Pinglv Yang, and Xiaoran Zhao
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convective cloud ,VISSR ,integrated method ,detection ,Meteorology. Climatology ,QC851-999 - Abstract
The characteristics of convective clouds on infrared brightness temperature (BTIR) and brightness temperature difference (BTD) image were analyzed using successive Infrared and Visible Spin-Scan Radiometer (VISSR) data of FY-2, and an integrated detection method of convective clouds using infrared multi-thresholds in combination with tracking techniques was implemented. In this method, BT and BTD thresholds are used to detect severe convection and uncertain clouds, then the tracking technique including overlap ratio, minimum BT change and cross-correlation coefficient is used to detect convection activities in uncertain clouds. The Application test results show that our integrated detection method can effectively detect convective clouds in different life periods, which show a better performance than any single step in it. The statistical results show that the α-type clouds are mostly large-scale systems, and the β- and γ-type clouds have the highest proportion of general type. However, the proportion of weak convective cloud is higher than that of severe ones in γ-type cloud, and an opposite result is found in the β-type.
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- 2017
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18. Properties of the Long-Term Oscillations in the Middle Atmosphere Based on Observations from TIMED/SABER Instrument and FPI over Kelan
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Yiyao Zhang, Zheng Sheng, Hanqing Shi, Shudao Zhou, Weilai Shi, Huadong Du, and Zhiqiang Fan
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SAO ,TO ,MIL ,amplitude ,phase ,Meteorology. Climatology ,QC851-999 - Abstract
The properties of the long-term oscillations in the middle atmosphere have been investigated using the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature data and Fabry–Perot interferometer (FPI) data. Results for SABER temperature show that the semiannual oscillation (SAO) has three amplitude maxima at altitudes of 45, 75, and 85 km, respectively, and shows prominent seasonal asymmetries there. The SAOs in the upper mesosphere (75 km) are out of phase with those in the mesopause (85 km) in the tropical regions, which can generate an enhancement of 11 K on average at each equinox, contributing to the lower mesospheric inversion layer (MIL). It is shown that stronger enhancement can be found at the spring equinox than at the autumn equinox. The triennial oscillation (TO) is significant in the tropical region. The spectral peak of the TO is probably a sub-peak of the quasi-biennial oscillation (QBO) and is due to modulation of QBO. In addition, there may be potential interaction of the TO with SAO at 85 km at the equator. The relation between ENSO and TO has also been discussed. The ENSO signal may modulate the amplitude of the TO, mainly in the lower stratosphere. The annual oscillation (AO) and SAO are analyzed over Kelan by FPI data. Generally, the amplitudes of FPI wind are smaller than those of the Horizontal Wind Model (HWM07). The comparison between FPI and TIMED Doppler Interferometer (TIDI) winds shows relatively large discrepancy. This may be due to the tidal aliasing in the nighttime results derived from the FPI data. Results also show that the algorithm to derive FPI temperature needs improvements.
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- 2017
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19. Inversion of Nighttime PM2.5 Mass Concentration in Beijing Based on the VIIRS Day-Night Band
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Xiaoran Zhao, Hanqing Shi, Hong Yu, and Pinglv Yang
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low-light ,nighttime PM2.5 ,VIIRS/DNB ,BP neural network ,Meteorology. Climatology ,QC851-999 - Abstract
In order to monitor nighttime particular matter (PM) air quality in urban area, a back propagation neural network (BP neural network) inversion model is established, using low-light radiation data from the day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (S-NPP) satellite. The study focuses on the moonless and cloudless nights in Beijing during March–May 2015. A test is carried out by selecting surface PM2.5 data from 12 PM2.5 automatic monitoring stations and the corresponding night city light intensity from DNB. As indicated by the results, the linear correlation coefficient (R) between the results and the corresponding measured surface PM2.5 concentration is 0.91, and the root-mean-square error (RMSE) is 14.02 μg/m3 with the average of 59.39 μg/m3. Furthermore, the BP neural network model shows better accuracy when air relative humility ranges from 40% to 80% and surface PM2.5 concentration exceeds 40 μg/m3. The study provides a superiority approach for monitoring PM2.5 air quality from space with visible light remote sensing data at night.
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- 2016
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20. Joint Inversion of Atmospheric Refractivity Profile Based on Ground-Based GPS Phase Delay and Propagation Loss
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Qixiang Liao, Zheng Sheng, and Hanqing Shi
- Subjects
atmospheric duct ,global positioning system (GPS) ,joint inversion ,refractivity profile ,remote sensing ,Meteorology. Climatology ,QC851-999 - Abstract
In this paper, we present a new estimation of the atmospheric refractivity profile combining the scattering signal (electromagnetic wave propagation loss) and the direct signal (phase delay). The refractivity profile is modeled using four parameters, i.e., the gradient of the refractivity profile (c1, c2) and the vertical altitude (h1, h2). We apply the NSGA-II (Non-dominated Sorting Genetic Algorithm II), a multiobjective optimization algorithm, to achieve the goals of joint optimization inversion in the inverting process, and compare this method with traditional individual inversion methods. The anti-noise ability of joint inversion is investigated under the noiseless condition and adding noise condition, respectively. The numerical experiments demonstrate that joint inversion is superior to individual inversion. The adding noise test further suggests that this method can estimate synthesized parameters more efficiently and accurately in different conditions. Finally, a set of measured data is tested in the new way and the consequence of inversion shows the joint optimization inversion algorithm has feasibility, effectiveness and superiority in the retrieval of the refractivity profile.
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- 2016
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21. Configuration Design and Evaluation of Bionic Grinding Manipulator Based on Human Upper Limb.
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Jinzhu Zhang, Hanqing Shi, Tao Wang 0045, Xinjun Liu, Li Jiang, and Qingxue Huang
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- 2021
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22. Cavitation cloud dynamic characteristics of dual-chamber self-excited oscillatory waterjet
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Dezheng Li, Yong Kang, Hanqing Shi, Yi Hu, Qi Liu, Hongchao Li, Jincheng Hu, and Jiamin Li
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General Chemical Engineering ,General Chemistry - Published
- 2022
23. Parameter Estimation of Nonlinear Systems by Dynamic Cuckoo Search.
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Qixiang Liao, Shudao Zhou, Hanqing Shi, and Weilai Shi
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- 2017
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24. Configuration Design of Lower-Mobility Parallel Driving Mechanisms
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Jinzhu Zhang, Xinjun Liu, Hanqing Shi, Yangyang Huang, and Qingxue Huang
- Published
- 2023
25. Inversion for Refractivity Parameters Using a Dynamic Adaptive Cuckoo Search with Crossover Operator Algorithm.
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Zhihua Zhang, Sheng Zheng, Hanqing Shi, and Zhiqiang Fan
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- 2016
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26. Segmentation for remote sensing image with shape and spectrum prior.
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Pinglv Yang, Zeming Zhou, Sixun Huang, and Hanqing Shi
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- 2016
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27. Nuclear localization of human MEIOB requires its NLS in the OB domain and interaction with SPATA22
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Yating Xu, Zhen Chen, Panfeng Wu, Wei Qu, Hanqing Shi, Muyang Cheng, Yumin Xu, Tingyu Jin, Cong Liu, Yi Li, and Mengcheng Luo
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Biophysics ,General Medicine ,Biochemistry - Abstract
MEIOB is a vital protein in meiotic homologous recombination and plays an indispensable role in human gametogenesis. In mammals, MEIOB and its partner SPATA22 form a heterodimer, ensuring their effective localization on single-strand DNA (ssDNA) and proper synapsis processes. Mutations in human MEIOB (hMEIOB) cause human infertility attributed to the failure of its interaction with human SPATA22 (hSPATA22) and ssDNA binding. However, the detailed mechanism is still unclear. In our study, truncated or full-length hMEIOB and hSPATA22 are traced by fused expression with fluorescent proteins (i.e., copGFP or mCherry), and the live cell imaging system is used to observe the expression and localization of the proteins. When transfected alone, hMEIOB accumulates in the cytoplasm. Interestingly, a covered NLS in the OB domain of hMEIOB is identified, which can be exposed by hSPATA22 and is necessary for the nuclear localization of hMEIOB. When hSPATA22 loses its hMEIOB interacting domain or NLS, the nuclear localization of hMEIOB is aborted. Collectively, our results prove that the NLS in the OB domain of hMEIOB and interaction with hSPATA22 are required for hMEIOB nuclear localization.
- Published
- 2022
28. Construction and Performance Evaluation of Dual-Metabolite Oil-Producing Engineering Bacteria Suitable for Low-Permeability Reservoir
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Yang, Zhao, primary, Zhihua, Guo, additional, JingChun, Wu, additional, and Hanqing, Shi, additional
- Published
- 2022
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29. Mechanism design and kinematic analysis of a bioinspired 5-DOF parallel driving mechanism
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Hanqing Shi, Jinzhu Zhang, Tao Wang, Ran Li, and Qingxue Huang
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Mechanics of Materials ,Mechanical Engineering ,Bioengineering ,Computer Science Applications - Published
- 2023
30. Pan-sharpening: a fast variational fusion approach.
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Zeming Zhou, Yuanxiang Li, Hanqing Shi, Ning Ma, and Ji Shen
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- 2012
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31. Nuclear localization of human MEIOB requires its NLS in the OB domain and interaction with SPATA22.
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Yating Xu, Zhen Chen, Panfeng Wu, Wei Qu, Hanqing Shi, Muyang Cheng, Yumin Xu, Tingyu Jin, Cong Liu, Yi Li, and Mengcheng Luo
- Published
- 2023
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32. Experimental investigation on penetration performance of larger volume needle-free injection device
- Author
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Lei Qian, Hanqing Shi, Wu Ni, Yong Kang, and Dongping Zeng
- Subjects
0209 industrial biotechnology ,Materials science ,Small volume ,Liquid jet ,Mechanical Engineering ,02 engineering and technology ,Penetration (firestop) ,Needle Free Injection ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Mechanics of Materials ,Response surface methodology ,Body orifice ,Critical volume ,Biomedical engineering ,Transdermal - Abstract
The injection performance of a small volume of needle-free injection (up to 0.3 mL) has proven to be controllable and satisfactory in transdermal drug delivery. However, no comprehensive research on the behavior of larger volume injections with different requirements for clinical applications exists. This study aims to present the penetration characteristics of larger volume injections, including dynamic properties, dispersion pattern, and percent delivery. The researchers conduct impact and injection experiments with injection volumes from 0.1–1.0 mL, driving pressures of 0.5–1.75 MPa, and orifice diameters of 0.17–0.5 mm. This study uses high-speed photography and impact experiments to capture the dynamic properties of the liquid jet. The researchers observe the dispersion patterns of liquid penetration into the gels in the gel injection experiments and investigate the percentages of liquid delivered to the skin tissues in porcine tissues injection experiments. Moreover, this study uses the response surface methodology (RSM) to analyze the interactive effect between various injection parameters on the injection performance. Results describe the differences in penetration performance between larger volume injections and small volume injections, and the critical volume of the mentioned injections is approximately 0.6 mL.
- Published
- 2020
33. A Novel Controllable Pneumatic Needle-Free Injection System for Larger-Volume Drug Delivery
- Author
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Lei Qian, Wu Ni, Hanqing Shi, Yong Kang, and Dongping Zeng
- Subjects
Materials science ,Pharmaceutical Science ,02 engineering and technology ,030226 pharmacology & pharmacy ,03 medical and health sciences ,Drug Delivery Systems ,0302 clinical medicine ,Jet velocity ,Animals ,Skin ,Transdermal ,Reproducibility of Results ,Equipment Design ,021001 nanoscience & nanotechnology ,Needle Free Injection ,Rats ,Pharmaceutical Preparations ,Volume (thermodynamics) ,Needles ,Drug delivery ,Injection volume ,Lateral diffusion ,Injections, Jet ,0210 nano-technology ,Control methods ,Biomedical engineering - Abstract
Hypodermic needles and syringes are currently the main route of the transdermal administration. Many complaints associated with needle-stick injuries, needle phobia, and needle abuse have motivated the development of alternative drug delivery strategies. Pneumatic needle-free injections stand out from various alternative strategies because of the convenience in adjusting the driving pressure and the injection volume. This study proposed a novel control method of the pneumatic needle-free injection for delivering larger volume drugs to the target sites at desired rates and time by controlling the driving pressure. The dynamic characteristics of this injection mode were evaluated in the impact experiments and the results confirmed the reliability of this controllable system in controlling the outlet pressure and jet velocity. The injection performances of it were compared with that of other injection modes through in vivo and in vitro experiments. This controllable system was able to control the injection depth and it was more conducive to the lateral diffusion of the liquid jets in gelatin. Moreover, it could not only enlarge the diffusion of diclofenac solution in rats, but also accelerate the metabolism of diclofenac solution in rats. All experimental results confirmed the reliability of this controllable injection system.
- Published
- 2020
34. The P2RY12 receptor promotes VSMC-derived foam cell formation by inhibiting autophagy in advanced atherosclerosis
- Author
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Yuanyuan Li, Yanan Li, Yiliang Miao, Hui He, Yu Hu, Jianyong Liu, Huijuan Jin, Jiefang Chen, Bo Hu, Hanqing Shi, Yiping Dang, Yuxiao Liu, Yuan-Peng Xia, Shulan Pi, Xiaoqing Guo, Ling Mao, Zhenyu Yue, Lian Zhou, Quan-Wei He, and Cheng Yu
- Subjects
Male ,0301 basic medicine ,Vascular smooth muscle ,Lipolysis ,Myocytes, Smooth Muscle ,Biology ,Muscle, Smooth, Vascular ,Mice ,Phosphatidylinositol 3-Kinases ,03 medical and health sciences ,Atorvastatin ,Autophagy ,Animals ,Humans ,cardiovascular diseases ,Receptor ,Molecular Biology ,Foam cell ,030102 biochemistry & molecular biology ,Mechanism (biology) ,TOR Serine-Threonine Kinases ,Drug Synergism ,Cell Biology ,Middle Aged ,Atherosclerosis ,musculoskeletal system ,Receptors, Purinergic P2Y12 ,Clopidogrel ,Cell biology ,Cholesterol ,030104 developmental biology ,cardiovascular system ,Female ,lipids (amino acids, peptides, and proteins) ,Lysosomes ,Proto-Oncogene Proteins c-akt ,tissues ,Research Paper ,Foam Cells ,Signal Transduction - Abstract
Vascular smooth muscle cells (VSMCs) are an important source of foam cells in atherosclerosis. The mechanism for VSMC-derived foam cell formation is, however, poorly understood. Here, we demonstrate that the P2RY12/P2Y12 receptor is important in regulating macroautophagy/autophagy and VSMC-derived foam cell formation in advanced atherosclerosis. Inhibition of the P2RY12 receptor ameliorated lipid accumulation and VSMC-derived foam cell formation in high-fat diet-fed apoe(-/-) mice (atherosclerosis model) independent of LDL-c levels. Activation of the P2RY12 receptor blocked cholesterol efflux via PI3K-AKT, while genetic knockdown or pharmacological inhibition of the P2RY12 receptor inhibited this effect in VSMCs. Phosphoproteomic analysis showed that the P2RY12 receptor regulated the autophagy pathway in VSMCs. Additionally, activation of the P2RY12 receptor inhibited MAP1LC3/LC3 maturation, SQSTM1 degradation, and autophagosome formation in VSMCs. Genetic knockdown of the essential autophagy gene Atg5 significantly attenuated P2RY12 receptor inhibitor-induced cholesterol efflux in VSMCs. Furthermore, activation of the P2RY12 receptor led to the activation of MTOR through PI3K-AKT in VSMCs, whereas blocking MTOR activity (rapamycin) or reducing MTOR expression reversed the inhibition of cholesterol efflux mediated by the P2RY12 receptor in VSMCs. In vivo, inhibition of the P2RY12 receptor promoted autophagy of VSMCs through PI3K-AKT-MTOR in advanced atherosclerosis in apoe(-/-) mice, which could be impeded by an autophagy inhibitor (chloroquine). Therefore, we conclude that activation of the P2RY12 receptor decreases cholesterol efflux and promotes VSMC-derived foam cell formation by blocking autophagy in advanced atherosclerosis. Our study thus suggests that the P2RY12 receptor is a therapeutic target for treating atherosclerosis. Abbreviations: 2-MeSAMP: 2-methylthioadenosine 5′-monophosphate; 8-CPT-cAMP: 8-(4-chlorophenylthio)-adenosine-3ʹ,5ʹ-cyclic-monophosphate; ABCA1: ATP binding cassette subfamily A member 1; ABCG1: ATP binding cassette subfamily G member 1; ACTB: actin beta; ADPβs: adenosine 5′-(alpha, beta-methylene) diphosphate; ALs: autolysosomes; AMPK: AMP-activated protein kinase; APOA1: apolipoprotein A1; APs: autophagosomes; ATG5: autophagy related 5; ATV: atorvastatin; AVs: autophagic vacuoles; CD: chow diet; CDL: clopidogrel; CQ: chloroquine; DAPI: 4ʹ,6-diamidino-2-phenylindole; dbcAMP: dibutyryl-cAMP; DIL-oxLDL: dioctadecyl-3,3,3,3-tetramethylin docarbocyanine-oxLDL; EIF4EBP1/4E-BP1: eukaryotic translation initiation factor 4E binding protein 1; EVG: elastic van gieson; HE: hematoxylin-eosin; HDL: high-density lipoprotein; HFD: high-fat diet; KEGG: Kyoto Encyclopedia of Genes and Genomes; LDL-c: low-density lipoprotein cholesterol; LDs: lipid droplets; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; Masson: masson trichrome; MCPT: maximal carotid plaque thickness; MK2206: MK-2206 2HCL; NBD-cholesterol: 22-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl] amino)-23,24-bisnor-5-cholen-3β-ol; OLR1/LOX-1: oxidized low density lipoprotein receptor 1; ORO: oil Red O; ox-LDL: oxidized low-density lipoprotein; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; TIC: ticagrelor; ULK1: unc-51 like autophagy activating kinase 1; VSMCs: vascular smooth muscle cells
- Published
- 2020
35. A New Short-Term Prediction Method for Estimation of the Evaporation Duct Height
- Author
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Chaolei Li, Hanqing Shi, Jun Bao, Yanbo Mai, Zheng Sheng, and Qixiang Liao
- Subjects
010504 meteorology & atmospheric sciences ,General Computer Science ,Mean squared error ,Population ,0211 other engineering and technologies ,Evolutionary algorithm ,Chaotic ,Evaporation duct ,02 engineering and technology ,short-term prediction ,01 natural sciences ,General Materials Science ,Time series ,support vector regression ,education ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Mathematics ,education.field_of_study ,Artificial neural network ,General Engineering ,Darwinian evolutionary algorithm ,Mean absolute percentage error ,nonlinear chaotic time series ,back propagation neural network ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Algorithm ,lcsh:TK1-9971 ,Smoothing - Abstract
Evaporation duct is a kind of chaotic phenomenon over the ocean. In this paper, a new nonlinear prediction algorithm, the Darwinian evolutionary algorithm (DEA), is introduced to obtain the specific nonlinear formula $P(\cdot)$ of the chaotic phenomenon. Based on Darwinian natural selection and survival theory, the method first selects a suitable training set of samples, and then produces an initial population before going through an evolutionary process of selection, reproduction and mutation until the optimal individual is found. Finally, a specific expression for a nonlinear chaotic time series is obtained, which can realize the short-term prediction of evaporation duct height (EDH) quickly and accurately. After that, the DEA, the support vector regression (SVR), and the back propagation (BP) neural network were applied to predict the EDH which were formed over the ocean by using sounding data. After interpolation and smoothing of the original data, we selected the first 250 data as training samples and the last 115 data as test samples to test the effect of the EDA algorithm. The results showed that the root mean squared error (RMSE) for the DEA was about 7% less than that of the SVR and 10% less than that of BP neural network; the mean absolute percent error (MAPE) for the DEA was about 9% less than that of the SVR and 15% less than that of BP neural network. In addition, the DEA obtained, for the first time, a nonlinear expression for EDH, which provides an important reference for future research on the evaporation ducts.
- Published
- 2020
36. Experimental study on the effect of dissolved CO2 on cavitation erosion intensity by submerged waterjet
- Author
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Hanqing Shi, Yong Kang, Dongping Zeng, Deng Li, Yi Hu, and Qi Liu
- Subjects
Mechanics of Materials ,Materials Chemistry ,Surfaces and Interfaces ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2022
37. Long‐Term Trends and Solar Responses of the Mesopause Temperatures Observed by SABER During the 2002–2019 Period
- Author
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Xiaofeng Zhao, Hanqing Shi, Qianfeng Liao, Libin Weng, and Zheng Sheng
- Subjects
Physics ,Atmospheric Science ,Geophysics ,Space and Planetary Science ,Climatology ,Mesopause ,Earth and Planetary Sciences (miscellaneous) ,Period (geology) ,Term (time) - Published
- 2020
38. sLRP1 (Soluble Low-Density Lipoprotein Receptor-Related Protein 1): A Novel Biomarker for P2Y12 (P2Y Purinoceptor 12) Receptor Expression in Atherosclerotic Plaques
- Author
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Hui He, Hanqing Shi, Jiefang Chen, Yuan-Peng Xia, Yuxiao Liu, Bo Hu, Xiaoqing Guo, Yuanyuan Li, Cheng Yu, Shulan Pi, Ling Mao, and Lian Zhou
- Subjects
Male ,Vascular smooth muscle ,Receptor expression ,P2Y Purinoceptor ,Gene Expression ,Diet, High-Fat ,Muscle, Smooth, Vascular ,Mice ,P2Y12 ,Apolipoproteins E ,medicine ,Cyclic AMP ,Animals ,Receptor ,Mice, Knockout ,Chemistry ,Clopidogrel ,Cyclic AMP-Dependent Protein Kinases ,Actins ,Plaque, Atherosclerotic ,Receptors, Purinergic P2Y12 ,Mice, Inbred C57BL ,Gene Knockdown Techniques ,LDL receptor ,Cancer research ,Purinergic P2Y Receptor Antagonists ,Biomarker (medicine) ,Cardiology and Cardiovascular Medicine ,Biomarkers ,Low Density Lipoprotein Receptor-Related Protein-1 ,medicine.drug ,Signal Transduction ,Sterol Regulatory Element Binding Protein 2 - Abstract
Objective: Recent studies suggest that the P2Y12 (P2Y purinoceptor 12) receptor of vascular smooth muscle cells in atherosclerotic plaques aggravates atherosclerosis, and P2Y12 receptor inhibitors such as CDL (clopidogrel) may effectively treat atherosclerosis. It is imperative to identify an effective biomarker for reflecting the P2Y12 receptor expression on vascular smooth muscle cells in plaques. Approach and Results: We found that there was a positive correlation between the level of circulating sLRP1 (soluble low-density lipoprotein receptor-related protein 1) and the number of LRP1 + α-SMA + (α-smooth muscle actin), P2Y12 + , or P2Y12 + LRP1 + cells in plaques from apoE −/− mice fed a high-fat diet. Furthermore, activation of the P2Y12 receptor increased the expression and shedding of LRP1 in vascular smooth muscle cells by inhibiting cAMP (3'-5'-cyclic adenosine monophosphate)/PKA (protein kinase A)/SREBP-2 (sterol regulatory element binding transcription factor 2). Conversely, genetic knockdown or pharmacological inhibition of the P2Y12 receptor had the opposite effects. Additionally, CDL decreased the number of lesional LRP1 + α-SMA + cells and the levels of circulating sLRP1 by activating cAMP/PKA/SREBP-2 in apoE −/− mice fed a high-fat diet. Conclusions: Our study suggests that sLRP1 may be a biomarker that reflects the P2Y12 receptor level in plaques and has the potential to be an indicator for administering P2Y12 receptor inhibitors for patients with atherosclerosis.
- Published
- 2020
39. A New Diagnostic Model and Improved Prediction Algorithm for the Heights of Evaporation Ducts
- Author
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Hanqing Shi, Chaolei Li, Wei Zhang, Yanbo Mai, Shudao Zhou, Zheng Sheng, Qixiang Liao, and Lihang Liu
- Subjects
Richardson number ,010504 meteorology & atmospheric sciences ,Series (mathematics) ,Mean squared error ,AR algorithm ,Evaporation ,010502 geochemistry & geophysics ,01 natural sciences ,Wind speed ,Support vector machine ,new diagnostic height model ,evaporation duct heights ,Mean absolute percentage error ,Simulated annealing ,General Earth and Planetary Sciences ,lcsh:Q ,time series ,lcsh:Science ,improved SVR algorithm ,Algorithm ,0105 earth and related environmental sciences ,Mathematics - Abstract
This paper develops a new method for the diagnosis and prediction of the evaporation duct heights on the sea, which has certain reference significance for the study of the evaporation ducts. Based on traditional diagnostic and predictive models of evaporation duct heights, a new diagnostic model is proposed. By determining the overall Richardson number Rib, the Monin-Obukhov (M-O) length L and the wind speed characteristic parameter u∗, temperature characteristic parameter θ∗ and humidity characteristic parameters q∗ are calculated, and then the evaporation duct height is diagnosed. Taking the diagnosed heights as a time series, and using the support vector regression (SVR) algorithm improved by a simulated annealing operator, then the time series is analyzed by taking three consecutive sample steps as input and the next sample step as output in order to develop an algorithm for predicting future heights. Finally, the prediction results are compared with those from the traditional auto-regressive (AR) algorithm and classical SVR algorithm to identify the advantages and disadvantages of the improved SVR algorithm. The results show that the root-mean-square error (RMSE) of the traditional AR, the classical SVR and the improved SVR algorithms is 0.60, 0.45, and 0.38, and the mean absolute percentage error (MAPE) of the three algorithms is 7.79%, 6.10% and 4.78%, respectively. The prediction error of the improved SVR algorithm is 37% less than that of the traditional AR algorithm and 15% less than that of the classical SVR algorithm, signifying an improvement in its prediction capability.
- Published
- 2020
40. Long-term trends and solar response of the mesopause temperatures observed by TIMED/SABER during the 2002-2019 period
- Author
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Xiaoran Zhao, Zheng Sheng, Hanqing Shi, Libin Weng, and Qixiang Liao
- Published
- 2020
41. An Idealized Method of Simulating Residual Ionospheric Errors in Radio Occultation
- Author
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Zheng Sheng, Zhiqiang Fan, Hanqing Shi, and Peng Guo
- Subjects
Physics ,Daytime ,Multidisciplinary ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,lcsh:R ,Magnitude (mathematics) ,lcsh:Medicine ,Residual ,01 natural sciences ,Asymmetry ,Article ,Computational physics ,Latitude ,Physics::Geophysics ,0103 physical sciences ,Physics::Space Physics ,Radio occultation ,lcsh:Q ,Ionosphere ,lcsh:Science ,010303 astronomy & astrophysics ,Noise (radio) ,0105 earth and related environmental sciences ,media_common - Abstract
An idealized model is used to simulate radio occultation bending angles and residual ionospheric errors. The test results of the proposed simulation method agree with those of previous studies that use end-to-end simulation tools. Also, a new residual ionospheric error model proposed by Healy and Culverwell (2015) is verified in this letter by characterizing the key parameter, κ. A simple model, κ(a) = A − B × (a − 20)/60, is used to estimate the values of κ, where A and B are constants that indicate the magnitude and variation of the values of κ, respectively, and a represents the impact height. When the modelled values of κ are applied in performing ionospheric corrections, the residual ionospheric errors decrease from approximately 5 × 10−8 rad to 1 × 10−9 rad at a latitude of 40°N during the daytime and at a solar activity level of F10.7 = 210. Though the proposed model does not assess other error terms, such as those associated with asymmetry and noise, it will likely prove to be an effective tool for describing idealized residual ionospheric errors in radio occultation, and the features of the κ values identified in this study may be helpful in improving ionospheric correction methods.
- Published
- 2017
42. Middle Atmosphere Temperature Changes Derived from SABER Observations during 2002-2020
- Author
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Y. He, Hanqing Shi, Zheng Sheng, Xiaofeng Zhao, and Libin Weng
- Subjects
Atmospheric Science ,Climatology ,Environmental science ,Atmospheric temperature - Abstract
Using temperature data measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument from February 2002 to March 2020, the temperature linear trend and temperature responses to the solar cycle (SC), Quasi-Biennial Oscillation (QBO), and El Niño-Southern Oscillation (ENSO) were investigated from 20 km to 110 km for the latitude range of 50°S-50°N. A four-component harmonic fit was used to remove the seasonal variation from the observed monthly temperature series. Multiple linear regression (MLR) was applied to analyze the linear trend, SC, QBO, and ENSO terms. In this study, the near-global mean temperature shows consistent cooling trends throughout the entire middle atmosphere, ranging from -0.28 to -0.97 K/decade. Additionally, it shows positive responses to the solar cycle, varying from -0.05 to 4.53 K/100sfu. A solar temperature response boundary between 50°S and 50°N is given, above which the atmospheric temperature is strongly affected by solar activity. The boundary penetrates deep below the stratopause to ~ 42 km over the tropical region and rises to higher altitudes with latitude. Temperature responses to the QBO and ENSO can be observed up to the upper mesosphere and lower thermosphere. In the equatorial region, 40%-70% of the total variance is explained by QBO signals in the stratosphere and 30%-50% is explained by the solar signal in the upper middle atmosphere. Our results, obtained from 18-year SABER observations, are expected to be an updated reliable estimation of the middle atmosphere temperature variability for the stratospheric ozone recovery period.
- Published
- 2021
43. An evaluation of new satellite-derived latent and sensible heat fluxes with moored buoy data, OAFlux and NCEP2 reanalysis products
- Author
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Lei Zhang and Hanqing Shi
- Subjects
010504 meteorology & atmospheric sciences ,Buoy ,Weather forecasting ,Aquatic Science ,Sensible heat ,010502 geochemistry & geophysics ,Oceanography ,computer.software_genre ,Atmospheric sciences ,01 natural sciences ,WINDSAT ,Wind speed ,Sea surface temperature ,Flux (metallurgy) ,Climatology ,Latent heat ,Environmental science ,computer ,0105 earth and related environmental sciences - Abstract
New satellite-derived latent and sensible heat fluxes are performed by using WindSat wind speed, WindSat sea surface temperature, the European Centre for Medium-range Weather Forecasting (ECMWF) air humidity, and ECMWF air temperature from 2004 to 2014. The 55 moored buoys are used to validate them by using the 30 min and 25 km collocation window. Furthermore, the objectively analyzed air-sea heat fluxes (OAFlux) products and the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis 2 (NCEP2) products are also used for global comparisons. The mean biases of sensible and latent heat fluxes between WindSat flux results and buoy flux data are–0.39 and–8.09 W/m2, respectively. In addition, the root-mean-square (RMS) errors of the sensible and latent heat fluxes between them are 5.53 and 24.69 W/m2, respectively. The RMS errors of sensible and latent heat fluxes are observed to gradually increase with an increasing buoy wind speed. The difference shows different characteristics with an increasing sea surface temperature, air humidity, and air temperature. The zonal average latent fluxes have some high regions which are mainly located in the trade wind zones where strong winds carry dry air in January, and the maximum value centers are found in the eastern waters of Japan and on the US east coast. Overall, the seasonal variability is pronounced in the Indian Ocean, the Pacific Ocean, and the Atlantic Ocean. The three sensible and latent heat fluxes have similar latitudinal dependencies; however, some differences are found in some local regions.
- Published
- 2017
44. Auroral oval segmentation using dual level set based on local information
- Author
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Hanqing Shi, Zeming Zhou, Pinglv Yang, and Yong Meng
- Subjects
010504 meteorology & atmospheric sciences ,Computer science ,business.industry ,Boundary (topology) ,02 engineering and technology ,01 natural sciences ,Term (time) ,Constraint (information theory) ,Distribution (mathematics) ,Level set ,Optics ,Feature (computer vision) ,Physics::Space Physics ,0202 electrical engineering, electronic engineering, information engineering ,Earth and Planetary Sciences (miscellaneous) ,020201 artificial intelligence & image processing ,Segmentation ,Astrophysics::Earth and Planetary Astrophysics ,Electrical and Electronic Engineering ,business ,Algorithm ,Intensity (heat transfer) ,0105 earth and related environmental sciences - Abstract
The extraction of auroral ovals from images acquired by the Ultraviolet Imager is notoriously difficult due to low contrast, inhomogeneity and the presence of dayglow. In this paper, to address these issues, we propose an improved level set segmentation algorithm by incorporating the shape feature and intensity distribution of the auroral oval into the variational framework. The shape term is proposed to keep the annular ring appearance of the auroral oval and avoid the boundary leak by imposing a distance constraint on the inner and outer boundaries. The local information term tackles the difficulty of intensity inhomogeneity by utilizing the statistical distribution in the local window. Experimental results demonstrate that the proposed method obtains more accurate inner and outer boundaries of the auroral oval, comparing to the existing pixel based and level set based methods.
- Published
- 2017
45. A Comparative Study on Evolutionary Multi-objective Optimization Algorithms Estimating Surface Duct
- Author
-
Wei Ge, Lei Zhang, Zheng Sheng, Qixiang Liao, Zhiyong Long, Hanqing Shi, and Lesong Zhou
- Subjects
atmospheric duct ,GPS, hypervolume ,010401 analytical chemistry ,Evolutionary algorithm ,Solution set ,02 engineering and technology ,inverted generational distance ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Multi-objective optimization ,Atomic and Molecular Physics, and Optics ,Article ,0104 chemical sciences ,Analytical Chemistry ,Hausdorff distance ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,lcsh:TP1-1185 ,multi-objective optimization algorithm ,Electrical and Electronic Engineering ,Instrumentation ,Algorithm ,Mathematics - Abstract
The problem of atmospheric duct inversion is usually solved as a single objective optimization problem. Based on ground-based Global Positioning System (GPS) phase delay and propagation loss, this paper develops a multi-objective method including the effect of source frequency and receiving antenna height. The diversity and convergence of solution sets are evaluated for seven multi-objective evolutionary algorithms with three performance metrics: Hypervolume (HV), Inverted Generational Distance (IGD), and the averaged Hausdorff distance ( Δ 2 ). The inversion results are compared with the simulation results, and the experimental comparison is conducted on three groups of test situations. The results demonstrate that the ranking of algorithm performance varies because of the different methods used to calculate performance metrics. Moreover, when the algorithms show overwhelming performance using performance metrics, the inversion result is not more close to the real value. In the comparison of computational experiments, it was found that, as the retrieved parameter dimension increases, the inversion result becomes more unstable. When the observed data are sufficient, the inversion result seems to be improved.
- Published
- 2018
46. Chaos particle swarm optimization combined with circular median filtering for geophysical parameters retrieval from Windsat
- Author
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Zhenzhan Wang, Lei Zhang, Zhiyong Long, Huadong Du, and Hanqing Shi
- Subjects
010504 meteorology & atmospheric sciences ,Meteorology ,Buoy ,Microwave radiometer ,0211 other engineering and technologies ,Particle swarm optimization ,Ocean Engineering ,02 engineering and technology ,Geophysics ,Wind direction ,Oceanography ,01 natural sciences ,WINDSAT ,Wind speed ,Sea surface temperature ,SSMIS ,Astrophysics::Solar and Stellar Astrophysics ,Environmental science ,Physics::Atmospheric and Oceanic Physics ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
This paper established a geophysical retrieval algorithm for sea surface wind vector, sea surface temperature, columnar atmospheric water vapor, and columnar cloud liquid water from WindSat, using the measured brightness temperatures and a matchup database. To retrieve the wind vector, a chaotic particle swarm approach was used to determine a set of possible wind vector solutions which minimize the difference between the forward model and the WindSat observations. An adjusted circular median filtering function was adopted to remove wind direction ambiguity. The validation of the wind speed, wind direction, sea surface temperature, columnar atmospheric water vapor, and columnar liquid cloud water indicates that this algorithm is feasible and reasonable and can be used to retrieve these atmospheric and oceanic parameters. Compared with moored buoy data, the RMS errors for wind speed and sea surface temperature were 0.92 m s−1 and 0.88°C, respectively. The RMS errors for columnar atmospheric water vapor and columnar liquid cloud water were 0.62 mm and 0.01 mm, respectively, compared with F17 SSMIS results. In addition, monthly average results indicated that these parameters are in good agreement with AMSR-E results. Wind direction retrieval was studied under various wind speed conditions and validated by comparing to the QuikSCAT measurements, and the RMS error was 13.3°. This paper offers a new approach to the study of ocean wind vector retrieval using a polarimetric microwave radiometer.
- Published
- 2016
47. WindSat satellite comparisons with nearshore buoy wind data near the U.S. west and east coasts
- Author
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Hanqing Shi, Xin Yi, Hong Yu, and Lei Zhang
- Subjects
Shore ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Meteorology ,Buoy ,Microwave radiometer ,0211 other engineering and technologies ,02 engineering and technology ,Aquatic Science ,Scatterometer ,Oceanography ,01 natural sciences ,WINDSAT ,Wind speed ,Climatology ,Satellite ,Longitude ,Geology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
Nearshore wind speeds retrieved by WindSat are validated by a comparison with the moored buoy observations near the U.S. west and east coasts. A 30 min and 25 km collection window is used for the WindSat wind data and buoy measurements from January 2004 to December 2014. Comparisons show that the overall root-mean-square error is better than 1.44 m/s near the U.S. coasts, and the result for the east coast is better than that for the west coast. The retrieval accuracy of the descending portions is slightly better than that of the ascending portions. Most buoy-to-buoy variations are not significantly correlated with the coastal topography, the longitude and the distance from the shore or satellite-buoy separation distance. In addition, comparisons between a polarimetric microwave radiometer and a microwave scatterometer are accomplished with the nearshore buoy observations from 2007 to 2008. The WindSat-derived winds tend to be lower than the buoy observations near the U.S. coasts. In contrast, the QuikSCAT-derived winds tend to be higher than the buoy observations. Overall, the retrieval accuracy of WindSat is slightly better than that of QuikSCAT, and these satellite-derived winds are sufficiently accurate for scientific studies.
- Published
- 2016
48. Comparison of WindSat and buoy-measured ocean products from 2004 to 2013
- Author
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Hanqing Shi, Xun Fang, Zhihua Zhang, Huadong Du, Enze Zhu, and Lei Zhang
- Subjects
010504 meteorology & atmospheric sciences ,Buoy ,Meteorology ,0211 other engineering and technologies ,02 engineering and technology ,Aquatic Science ,Wind direction ,Oceanography ,01 natural sciences ,WINDSAT ,Wind speed ,Latitude ,Sea surface temperature ,Climatology ,Environmental science ,Submarine pipeline ,Water vapor ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
To evaluate the ocean surface wind vector and the sea surface temperature obtained from WindSat, we compare these quantities over the time period from January 2004 to December 2013 with moored buoy measurements. The mean bias between the WindSat wind speed and the buoy wind speed is low for the low frequency wind speed product (WSPD_LF), ranging from–0.07 to 0.08 m/s in different selected areas. The overall RMS error is 0.98 m/s for WSPD_LF, ranging from 0.82 to 1.16 m/s in different selected regions. The wind speed retrieval result in the tropical Ocean is better than that of the coastal and offshore waters of the United States. In addition, the wind speed retrieval accuracy of WSPD_LF is better than that of the medium frequency wind speed product. The crosstalk analysis indicates that the WindSat wind speed retrieval contains some cross influences from the other geophysical parameters, such as sea surface temperature, water vapor and cloud liquid water. The mean bias between the WindSat wind direction and the buoy wind direction ranges from–0.46° to 1.19° in different selected regions. The overall RMS error is 19.59° when the wind speed is greater than 6 m/s. Measurements of the tropical ocean region have a better accuracy than those of the US west and east coasts. Very good agreement is obtained between sea surface temperatures of WindSat and buoy measurements in the tropical Pacific Ocean; the overall RMS error is only 0.36°C, and the retrieval accuracy of the low latitudes is better than that of the middle and high latitudes.
- Published
- 2016
49. Using the Decomposition-Based Multi-Objective Evolutionary Algorithm with Adaptive Neighborhood Sizes and Dynamic Constraint Strategies to Retrieve Atmospheric Ducts
- Author
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Wei Zhang, Shuai Zhao, Yanbo Mai, Zheng Sheng, Qingjian Ni, Qixiang Liao, and Hanqing Shi
- Subjects
010504 meteorology & atmospheric sciences ,Computer science ,Population ,atmospheric ducts ,Evolutionary algorithm ,new algorithm ,02 engineering and technology ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Article ,Evolutionary computation ,Analytical Chemistry ,0202 electrical engineering, electronic engineering, information engineering ,balance the diversity and convergence of the population ,lcsh:TP1-1185 ,Electrical and Electronic Engineering ,education ,Instrumentation ,0105 earth and related environmental sciences ,education.field_of_study ,GNSS ,special sensor ,Atomic and Molecular Physics, and Optics ,Hausdorff distance ,020201 artificial intelligence & image processing ,Algorithm - Abstract
The traditional method of retrieving atmospheric ducts is to use the special sensor of weather balloons or rocket soundings to obtain information intelligently, and it is very expensive. Today, with the development of technology, it is very convenient to retrieve the atmospheric ducts from Global Navigation Satellite System (GNSS) phase delay and propagation loss observation data, and then the GNSS receiver on the ground forms an automatic receiving sensor. This paper proposes a hybrid decomposition-based multi-objective evolutionary algorithm with adaptive neighborhood sizes (EN-MOEA/ACD-NS), which dynamically imposes some constraints on the objectives. The decomposition-based multi-objective evolutionary algorithm (MOEA/D) updates the solutions through neighboring objectives, the number of which affects the quality of the optimal solution. Properly constraining the optimization objectives can effectively balance the diversity and convergence of the population. The experimental results from the Congress on Evolutionary Computation (CEC) 2009 on test instances with hypervolume (HV), inverted generational distance (IGD), and average Hausdorff distance ∆2 metrics show that the new method performs similarly to the evolutionary algorithm MOEA/ACD-NS, which considers only the dynamic change of the neighborhood sizes. The improved algorithm is applied to the practical problem of jointly retrieving atmospheric ducts with GNSS signals, and its performance further demonstrates its feasibility and practicability.
- Published
- 2020
50. Estimation of Surface Duct Using Ground-Based GPS Phase Delay and Propagation Loss
- Author
-
Zheng Sheng, Qixiang Liao, Hanqing Shi, Hong Yu, and Jie Xiang
- Subjects
surface duct ,refractivity structure ,GPS ,remote sensing ,NSGA-II ,matched-field processing ,010504 meteorology & atmospheric sciences ,Computer science ,business.industry ,Science ,020206 networking & telecommunications ,Inversion (meteorology) ,02 engineering and technology ,01 natural sciences ,0202 electrical engineering, electronic engineering, information engineering ,Global Positioning System ,General Earth and Planetary Sciences ,Duct (flow) ,business ,Algorithm ,0105 earth and related environmental sciences ,Group delay and phase delay - Abstract
The propagation of Global Positioning System (GPS) signals at low-elevation angles is significantly affected by a surface duct. In this paper, we present an improved algorithm known as NSSAGA, in which simulated annealing (SA) is combined with the non-dominated sorting genetic algorithm II (NSGA-II). Matched-field processing was used to remotely sense the refractivity structure by using the data of ground-based GPS phase delay and propagation loss from multiple antenna heights. The performance was checked by simulation data with and without noise. In comparison with NSGA-II, the new hybrid algorithm retrieved the refractivity structure more efficiently under various noise conditions. We then modified the objective function and found that matched-field processing is more effective than the conventional least-squares method for inferring the refractivity parameters. Comparing the inversion results and in situ sounding data suggests that the improved method presented herein can capture refractivity characteristics in realistic environments.
- Published
- 2018
- Full Text
- View/download PDF
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