Zhaoyuan Yu

Nanjing Normal University · Key Laboratory of Virtual Geographic Environment Ministry of Education

A new Clifford algebra-based vector field filtering method, which combines amplitude similarity and direction difference synchronously, is proposed. Firstly, a modified correlation product is defined by combining the amplitude similarity and direction difference. Then, a structure filtering algorithm is constructed based on the modified correlation...

Principle Tensor Analysis of Rank 3 Method (PTA3) was applied to Equatorial Pacific satellite altimetry data during 1993 to 2008. The coupling process of the zonal and meridional sea level changes were reconstructed by the first two principle tensor components and compared using the longtidue and latitude components indexes during six typical perio...

Classical topological relation expressions and computations are primarily based on abstract algebra. In this article, the representation and computation of geometry-oriented topological relations (GOTR) are developed. GOTR is the integration of geometry and topology. The geometries are represented by blades, which contain both algebraic expressions...

In this paper, conformal geometric algebra (CGA) is introduced to construct a Delaunay–Triangulated Irregular Network (DTIN) intersection for change detection with 3D vector data. A multivector-based representation model is first constructed to unify the representation and organization of the multidimensional objects of DTIN. The intersection relat...

Aiming at the modeling and analysis of the multi-layer, multi-temporal geographical model simulation data, the geometric algebra (GA) is introduced to design methods for data modeling, spatio-temporal queries and dynamic visualization. Algorithms, including the slices and cross-section, area and volume computation, morphology characteristics comput...

Existing intervisibility analysis methods suffer from computational inefficiency due to redundant sampling points. To address this issue, we propose a new approximate method called line-of-sight (LoS) zoning, which leverages continuous terrain relief to identify potentially obscuring zones (POZ) of LoS. By limiting the sampling range to a much smal...

As a kind of first aid healthcare service, emergency medical services (EMSs) present high spatiotemporal sensitivity due to significant changes in the time-dependent urban environment. Taking full advantage of big spatiotemporal data to realize multiperiod relocation optimization of EMSs can reduce idle resources and improve service utilization eff...

The accurate simulation of climate is always critically important and also a challenge. This study introduces an improved method of the Globally Resolved Energy Balance (GREB) model by the Bayesian networks based on the concept of a coarse-fine model. The improved method constructs a coarse-fine structure that combines a dynamical model with a stat...

Combustion-driven particulate black carbon (PBC) is a crucial slow-cycling pool in the organic carbon flux from rivers to oceans. Since the refractoriness of PBC stems from the association of non-homologous char and soot, the composition and source of char and soot must be considered when investigating riverine PBC. Samples along the Yangtze River...

Digital twin (DT) has been applied to increasingly complex systems, including environments, energy, and digital cities, due to advancement of data collecting, high-speed networks, big data, artificial intelligence, and other technologies. Because of the complexity of the actual world and newly suggested criteria for the construction of the linkage...

The challenging geological conditions in hilly mountainous areas, combined with intensive human engineering activities, have led to a high frequency of landslide disasters. This is particularly true in karst mountainous areas where the geology is complex and characterized by distinct karst phenomena influenced by stratigraphy and severe terrain cut...

Research on healthcare accessibility is developing with a focus on multimodal transport modes (MTMs) and multiple time-series variations. A dynamic traffic environment leads travelers to make distinct decisions at different time slots, which impacts spatiotemporal accessibility markedly. Our article proposes a methodological framework to measure sp...

Assessing the trade network connectivity is essential for understanding the trade network structure, optimizing trade development patterns, and improving uneven trade development along the "Belt and Road" (BRI). From the perspective of connectivity, this paper integrates the frontier algorithms in network science and constructs an analytical framew...

Introduction: Although academic entrepreneurship has received considerable attention over the last decades, little attention has been devoted to discussing the formation process of academic entrepreneurial intention underlying the push-pull perspective. This study attempts to explore the mechanism of how academic entrepreneurial intention is shape...

Accurate and robust fine-grained expressway traffic volume simulation is a critical issue in intelligent transportation systems and real-time traffic-related applications. However, the fine-grained expressway traffic volumes aggregated from vehicle trajectories heavily rely on individual heterogeneity, making it challenging for modeling and accurat...

At small granularity (e.g., 10-minutes to hourly), expressway traffic volumes rely heavily on drivers’ driving habits heterogeneity and decision randomness, making it challenging for accurate modeling. In this paper, we propose a small granularity simulation model named Small-Granularity Expressway Traffic Volumes with Quantum Walks (SGETV-QW). The...

There is increasing demand for multi-level declassification of geographic vector field data in the big data era. Different from traditional encryption, declassification does not aim at making the original data unavailable through perturbation and transformation. During declassification process, the general geospatial features are usually retained b...

This study introduces an improved method of the Globally Resolved Energy Balance Model(GREB) by the Bayes network. Starting from the climate elements relationship included in the GREB model, we reconstruct the model by the Bayes network to solve the problem of low model accuracy due to over-reliance on boundary conditions and initial conditions and...

The study of urban functional zoning is not only important for analyzing urban spatial structure but also for optimizing urban management and promoting scientific urban planning. Different areas undertaking different urban functions correspond to different traffic patterns and specific cycles. Here, a method named Urban Functional Zoning based on t...

Geography is a comprehensive discipline that studies spatial–temporal patterns, evolution processes, and interaction mechanisms of geographic objects and phenomena. With the evolution of the world from a binary space to a ternary space, it is urgent to deepen and expand the understanding, expression, and mining of geographic information. Most curre...

Irregular geographic spatio-temporal-field data have been rapidly accumulating; however, data organizations and operations for different irregular types are often segregated, leading to systematic drawbacks, such as interface expansion difficulty and high coupling codes in GIS implementations. The paper proposes a unified approach to organizing and...

The multi‐scale characteristic of online car‐hailing traffic volume can reflect the implied distribution pattern, which is crucial for traffic management and even urban planning. Nevertheless, the spatio‐temporal heterogeneity of online car‐hailing traffic volume makes it challenging to analyze its multi‐scale characteristics effectively. Here, a m...

The traditional landslide risk research mostly focuses on the spatial distribution of landslide occurrence probability, but the research on the time distribution of landslide occurrence probability is not in-depth, and there is no effective professional management advice for specific risk areas, so it has great limitations. This paper takes the lan...

Remote sensing image watermarking algorithm has weak resistance to geometric attacks; therefore, paper proposes a reversible watermarking algorithm based on SURF (Speeded Up Robust Features) feature points to select ROI and embed mid and low-frequency subbands, respectively, which can effectively resist geometric attack. The algorithm first extract...

Considering the embarrassments related to inadequate safety monitoring detection and chaotic development order during the current ecological development of coastal tidal mudflat, we put forward a remote sensing image-based comprehensive monitoring detection platform integrating image data acquisition, mechanism analysis, comprehensive evaluation, a...

In intercity expressway traffic, the multiplicity of available routes leads to randomness in exit selection. Random exit selection by drivers is hard to observe, and thus it is a challenge to model intercity expressway traffic sufficiently. In this paper, we developed a Random Quantum Traffic Model (RQTM), which modeled the stochastic traffic fluct...

The development trend of ternary space requires the construction of the information space for information mapping, transmission and transformation of geographic elements and social-human elements. Relevant researches of Information Geography from the perspective of Geographic Information Science and Human Geography are reviewed in this paper, then...

Roadside trees alter biotic and abiotic factors of plants diversity in an ecosystem. Rows of plants grow along the roadside due to the interplay between the arrival of propagule and seedling establishment, which depends on the road’s specifications, land pattern, and road administration and protection practices. A field study was conducted to measu...

Global geodetic stations are the basis for the study of International Terrestrial Reference Frame (ITRF) and crustal plate motion. This paper has collected a total of 288 global geodetic stations calculated by four spatial geodetic technologies. Because different types of geodetic stations use different spatial references, the data of different typ...

Following the outbreak of the novel coronavirus in early 2020, to effectively prevent the spread of the disease, major cities across China suspended work and production. While the rest of the world struggles to control COVID-19, China has managed to control the pandemic rapidly and effectively with strong lockdown policies. This study investigates...

Currently, the different deep neural network (DNN) learning approaches have done much for the classification of hyperspectral images (HSIs), especially most of them use the convolutional neural network (CNN). HSI data have the characteristics of multidimensionality, correlation, nonlinearity, and a large amount of data. Therefore, it is particularl...

Predicting entry-traffic flows synchronously could enable inferences about the changing trends and spatial structure of dynamic traffic flows in an expressway network. This research develops a synchronized entry-traffic flow prediction method for regional expressway systems. The new method first organizes numerous entry-traffic flows as a three-dim...

The accessibility of electric vehicle charging stations (EVCS) is one of the critical factors affecting energy vehicles’ development. It is also the root cause restricting the replacement of fuel vehicles by new energy vehicles. All kinds of dynamic factors in the city, such as population and traffic, will directly affect the spatiotemporal accessi...

Traffic congestion in expressway networks has a strong negative influence on regional development. Understanding the spatiotemporal patterns of traffic congestion in expressway networks is critical for improving the exchange of products in regional production and promoting regional economic development. Nevertheless, existing studies pay less atten...

Roads have a great impact on the structure and functioning of the diversity pattern in an ecological environment and play the role of altering biotic and abiotic factors. Clusters of plants grow along the roadside due to the interplay between the arrival of propagule and seedling establishment, which depends on the road’s specifications, land patte...

Digital watermarking technology, as a powerful tool for copyright protection and content authentication of multimedia works, has received increasing attention, and the current image watermarking technology has developed significantly. Generally, embedding a watermark is done in grayscale images, mainly due to the fact that grayscale images are easi...

Fast and precise querying in a given set of trajectory points is an important issue of trajectory query. Typically, there are massive trajectory data in the database, yet the query sets only have a few points, which is a challenge for the superior performance of trajectory querying. The current trajectory query methods commonly use the tree-based i...

Periodic behaviors are essential to understanding objects’ movements. In real world situations, the collective movement of moving objects hides useful periodic patterns that people are more interested in. Discovering such periodic patterns is helpful in exploring human mobility, which can benefit many applications, such as urban planning, traffic m...

Quantitative measurement of the heterogeneity in the intensity of human interference is key to accurately assessing the impact of human activity. The same human activities in different landscape configurations should have different impacts. This study constructed a weighted analysis to describe and measure heterogeneity under the Hemeroby index mod...

Current development of Pakistan’s economy, transportation and industry with the improvement of urbanization, environmental pollution problems have gradually become prominent, but this is contrary to people’s vision of pursuing a high-quality life. Now the problem of haze, photochemical problems in the air, and global warming is already a key issue...

Edge detection is widely used for image processing to improve the detection and classification of objects, segmentation, and extraction of other features. Satellite images are rich in information about objects with different color intensity and have a large amount of noise, so it is difficult to achieve recognition, classification, and feature extr...

Lossy compression has been applied to the data compression of large-scale Earth system model data (ESMD) due to its advantages of a high compression ratio. However, few lossy compression methods consider both global and local multidimensional coupling correlations, which could lead to information loss in data approximation of lossy compression. Her...

Healthcare diseases are spreading all around the globe day to day. Hospital datasets are full from the data with much information. It's an urgent requirement to use that data perfectly and efficiently. We propose a novel algorithm for predictive model for eye diseases using KNN with machine learning algorithms and artificial intelligence (AI). The...

The diversity of GIS application patterns leads to the demand for multilevel GIS data declassification. For example, Publicly used data must be declassified to hide confidential spatial information. The reversion process is not a common data permutation like the conventional encryption method does. The reverted data should also keep the general geo...

A group event such as human and traffic congestion can be very roughly divided into three stages: converging stage before congestion, gathered stage when congestion happens, and dispersing stage that congestion disappears. It is of great interest in modeling and identifying converging behaviors before gathered events actually happen, which helps to...

With the increasing demand for multidimensional data processing, Geometric algebra (GA) has attracted more and more attention in the field of geographical information systems. GA unifies and generalizes real numbers and complex, quaternion, and vector algebra, and converts complicated relations and operations into intuitive algebra independent of c...

Accessibility research of healthcare facilities is developing towards multiple transportation modes (MTM), which are influenced by residential transportation choices and preferences. Due to differences in travel impact factors such as traffic conditions, origin location, distance to the destination, and economic cost, residents’ daily travel presen...

Background: Healthcare accessibility research is developing towards a focus on multimodal transport modes (MTM) and spatiotemporal variation. Dynamic traffic conditions lead residents to make distinct traveling decisions in different timepoints, which has an impact on the spatiotemporal accessibility of healthcare. Pediatric clinic services (PCS) a...

Abstract. Lossy compression has been applied to large-scale experimental model data compression due to its advantages of a high compression ratio. However, few methods consider the uneven distribution of compression errors affecting compression quality. Here we develop an adaptive lossy compression method with the stable compression error for earth...

With the widespread use of color images, the copyright protection of those images using watermarks is one of the latest research topics. The use of color images as watermarks has advantages over binary and irreplaceable grayscale images. Color images are intuitive, rich, and lively; they have large amounts of copyright protection information and mo...

In intercity expressway traffic, a driver frequently makes decisions to adjust driving behavior according to time, location and traffic conditions, which further affects when and where the driver will leave away from the expressway traffic. Spontaneous exit choices by drivers are hard to observe and thus it is a challenge to model intercity express...

Abstract Heterogeneity is an essential characteristic of the geographic phenomenon. However, most existing researches concerning heterogeneity are based on the matrix. The bidimensional nature of the matrix cannot well support the multidimensional analysis of spatiotemporal field data. Here, we introduce an improved tensor‐based feature analysis me...

A semantic trajectory is a combination of a spatiotemporal trajectory and semantic information. Besides spatiotemporal information, a semantic trajectory comprises movement states (e.g. speed, direction), external contextual information (e.g. temperature, spatial topological relationships), and social relationships (e.g. friend relationships, socia...

Digital watermarking is important for protecting the intellectual property of remote sensing images. Unlike watermarking in ordinary colour images, in colour remote sensing images, watermarking has an important requirement: robustness. In this paper, a robust nonblind watermarking scheme for colour remote sensing images, which considers both freque...

Due to the increasing complexity of GIS data and service modes, there is an urgent need for the next generation of GIS with new representation and computation methods. A number of spatiotemporal models, analytical and visualization methods, as well as system architectures have been proposed. However, previous studies failed to integrate basic geogr...

Feature analysis of weak nonlinear signals from geographic spatiotemporal data has received increasing attention. Most existing signal processing methods cannot effectively perform comprehensive feature analysis because of the multiple dimensions and unbalance of spatiotemporal data. We developed a divide–aggregate–explore method for the feature an...

In this paper, a tensor-based interpolation method for spatio-temporal field data is proposed. The observed data are organized as a sparse tensor, which is then represented as the decomposition of a canonical polyadic (CP) model. The latent factors, abstracting the underlying structure of sparse data, are exploited by introducing a weighted optimiz...

This paper presents an approach for indoor reconstruction using smartphones. The smartphones sensors are used for measuring the azimuth angle and pitch angle. With these angles, the rooms of the indoor scene are effectively reconstructed. Then the separately reconstructed models are aligned together to form a complete model. Meanwhile, the conforma...