Yiyuan Sun

Mr. Yiyuan Sun

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 September 2020 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Sana UllahSana Ullah
Sana Ullah
ZZZhengkang Zuo
Zhengkang Zuo
FZFeiZhou Zhang
FeiZhou Zhang
JZjianghua Zheng
jianghua Zheng
SHShifeng Huang
Shifeng Huang
LYLei Yan
Lei Yan
To obtain the high-resolution multitemporal precipitation using spatial downscaling technique on a precipitation dataset may provide a better representation of the spatial variability of precipitation to be used for different purposes. In this research, a new downscaling methodology such as the global precipitation mission (GPM)-based multitemporal weighted precipitation analysis (GMWPA) at 0.05° resolution is developed and applied in the humid region of Mainland China by employing the GPM dataset at 0.1° and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) 30 m DEM-based geospatial predictors, i.e., elevation, longitude, and latitude in empirical distribution-based framework (EDBF) algorithm. The proposed methodology is a two-stepped process in which a scale-dependent regression analysis between each individual precipitation variable and the EDBF-based weighted precipitation with geospatial predictor(s), and to downscale the predicted multitemporal weighted precipitation at a refined scale is developed for the downscaling of GMWPA. While comparing results, it shows that the weighted precipitation outperformed all precipitation variables in terms of the coefficient of determination (R2) value, whereas they outperformed the annual precipitation variables and underperformed as compared to the seasonal and the monthly variables in terms of the calculated root mean square error (RMSE) value. Based on the achieved results, the weighted precipitation at the low-resolution (e.g., at 0.75° resolution) along-with the original resolution (e.g., at 0.1° resolution) is employed in the downscaling process to predict the average multitemporal precipitation, the annual total precipitation for the year 2001 and 2004, and the average annual precipitation (2001–2015) at 0.05° resolution, respectively. The downscaling approach resulting through proposed methodology captured the spatial patterns with greater accuracy at higher spatial resolution. This work showed that it is feasible to increase the spatial resolution of a precipitation variable(s) with greater accuracy on an annual basis or as an average from the multitemporal precipitation dataset using a geospatial predictor as the proxy of precipitation through the weighted precipitation in EDBF environment.

Verified
Journal Article
Open access
PDF file
YSYiyuan Sun
Yiyuan Sun
QWQiang WANG
Qiang WANG
Kevin TanseyKevin Tansey
Kevin Tansey
Sana UllahSana Ullah
Sana Ullah
FLFan Liu
Fan Liu
LYLei Yan
Lei Yan
Image-based line segment extraction plays an important role in a wide range of applications. Traditional line segment extraction algorithms focus on the accuracy and efficiency, without considering the integrity. Serious line segmentation fracture problems caused by image quality will result in poor subsequent applications. To solve this problem, a multi-constrained line segment extraction method, based on multi-scale image space, is presented. Firstly, using Gaussian down-sampling with a classical line segment detection method, a multi-scale image space is constructed to extract line segments in each image scale and all line segments are projected onto the original image. Then, a new line segment optimization and purification strategy is proposed with the horizontal and vertical distances and angle geometric constraint relationships between line segments to merge fracture line segments and delete redundant line segments. Finally, line segments with adjacent positions are optimized using the grayscale constraint relationship, based on normalized cross-correlation similarity criterion for realizing the second optimization of fracture line segments. Compared with mainstream line segment detector and edge drawing lines methods, experimental results (i.e., indoor, outdoor, and aerial images) indicate the validity and superiority of our proposed methods which can extract longer and more complete line segments.

5 April 2021 in Earth's Future
Verified
Journal Article
Open access
PDF file
ZZZhengkang Zuo
Zhengkang Zuo
SUSana Ullah
Sana Ullah
LYLei Yan
Lei Yan
YSYiyuan Sun
Yiyuan Sun
FPFei Peng
Fei Peng
HZHongying Zhao
Hongying Zhao
Natural and non‐natural factors have combined effects on the trajectory of COVID‐19 pandemic, but it is difficult to make them separate. To address this problem, a two‐stepped methodology is proposed. First, a compound natural factor (CNF) model is developed via assigning weight to each of seven investigated natural factors, that is temperature, humidity, visibility, wind speed, barometric pressure, aerosol, and vegetation in order to show their coupling relationship with the COVID‐19 trajectory. Onward, the empirical distribution based framework (EDBF) is employed to iteratively optimize the coupling relationship between trajectory and CNF to express the real interaction. In addition, the collected data is considered from the backdate, that is about 23 days—which contains 14‐days incubation period and 9‐days invalid human response time—due to the nonavailability of prior information about the natural spreading of virus without any human intervention(s), and also lag effects of the weather change and social interventions on the observed trajectory due to the COVID‐19 incubation period; Second, the optimized CNF‐plus‐polynomial model is used to predict the future trajectory of COVID‐19. Results revealed that aerosol and visibility show the higher contribution to transmission, wind speed to death, and humidity followed by barometric pressure dominate the recovery rates, respectively. Consequently, the average effect of environmental change to COVID‐19 trajectory in China is minor in all variables, that is about −0.3%, +0.3%, and +0.1%, respectively. In this research, the response analysis of COVID‐19 trajectory to the compound natural interactions presents a new prospect on the part of global pandemic trajectory to environmental changes.

26 September 2020
Verified
Conference Paper
Closed access
ZZZhengkang Zuo
Zhengkang Zuo
YSYiyuan Sun
Yiyuan Sun
RZRuihua Zhang
Ruihua Zhang
LYLei Yan
Lei Yan
In this work, a Constraint Law method (CLM) based Genetic Algorithm (CLM-GA) is proposed for Nonlinear Least Square (LS) Regression and Normal Optimization Problems (NOP). Numerical experimental results show that CLM-GA is more robust than traditional methods (Gauss Newton, Levernberg Marquardt, EM-GA, EDBF-GA) for both LS and NOP problems in three aspects: 1) efficiency; 2) accuracy; 3) astringency. There are many LS and NOP applications in the physical world, such as military, economics, industry, photogrammetry and so on. Research of this paper can be easily implemented and applied for those applications.

12 September 2017 in The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Verified
Journal Article
Open access
PDF file
XTX. Tan
X. Tan
XJXin Jing
Xin Jing
RCR. Chen
R. Chen
ZMZ. Ming
Z. Ming
HLHe Liqin
He Liqin
LYLei Yan
Lei Yan
Keywords: Remote Sensing, Spatial Information, Cybernetics, System Practice, Closed-loop control Cybernetics provides a new set of ideas and methods for the study of modern science, and it has been fully applied in many areas. However, few people have introduced cybernetics into the field of remote sensing. The paper is based on the imaging process of remote sensing system, introducing cybernetics into the field of remote sensing, establishing a space-time closed-loop control theory for the actual operation of remote sensing. The paper made the process of spatial information coherently, and improved the comprehensive efficiency of the space information from acquisition, procession, transformation to application. We not only describes the application of cybernetics in remote sensing platform control, sensor control, data processing control, but also in whole system of remote sensing imaging process control. We achieve the information of output back to the input to control the efficient operation of the entire system. This breakthrough combination of cybernetics science and remote sensing science will improve remote sensing science to a higher level.

12 June 2020 in medRxiv
Verified
Preprint
Open access
PDF file
Sana UllahSana Ullah
Sana Ullah
ZJZheng Jianghua
Zheng Jianghua
ZZZhengkang Zuo
Zhengkang Zuo
FZFeiZhou Zhang
FeiZhou Zhang
Ke ShangKe Shang
Ke Shang
LYLei Yan
Lei Yan
Since mid-March 2020, global COVID-19 pandemic has experienced an exponential growth in process from sporadic to sudden outbreaks. This paper selects the 8-day surge data of daily cases, death and recovery rates (March 19-26, 2020) from 18 countries with severe pandemic situation to discuss the impact of 9 factors of both socioeconomic and natural on the pathogen outbreak. Moreover, the paper also elaborates analysis and comparison of relatively slow 4-week (February 1-29, 2020) data of China’s surge cases to determine the relationship between social and natural factors and on the spread of pandemic, which provides an effective reference for delaying and controlling the pandemic development.