Weighted Voronoi Diagram Research Articles

Visual simulation of opal using bond percolation through the weighted Voronoi diagram and the Ewald construction

Visual simulation of opal using bond percolation through the weighted Voronoi diagram and the Ewald construction

Towards Resilient Cities: Optimizing Shelter Site Selection and Disaster Prevention Life Circle Construction Using GIS and Supply-Demand Considerations

City health examinations are integral to China’s urban planning, construction, and management. They effectively identify potential risks and vulnerabilities in urban development, ensuring safety resilience—a critical component. This resilience enhances the city’s ability to withstand internal and external shocks, promoting the safety of urban residents and fostering sustainable city development. Drawing on the Japanese disaster prevention strategy, the disaster prevention life circle emerges as a rescue and protection system during urban disasters, fortifying urban safety resilience. However, smaller and mid-sized cities, constrained by limited resources, significantly need to catch up in disaster prevention planning. Consequently, bolstering safety resilience in these cities becomes a pressing concern. This study focuses on Lindian County in Heilongjiang Province as the urban area under consideration for resilient city objectives. Leveraging the ArcGIS network analysis tool, we optimize the placement of emergency shelters, aligning with urban disaster assessments and the equilibrium of disaster prevention facility supply and demand. Accessibility analysis of emergency shelters was conducted using the Gaussian two-step floating catchment area method. Ultimately, we integrate the range of demand points assigned to each shelter, along with the effective land area reflecting the supply of shelters, as weights into a weighted Voronoi diagram. This diagram is combined with a reference to the entire region to delineate the disaster prevention life circle. Findings reveal that, under the premise of minimizing government construction costs while maximizing coverage and evacuation utilization rates, the optimal resident emergency congregate shelters in the study area are 8, with 98 emergency evacuation and embarkation shelters. Striking a balance between disaster prevention facility supply and demand and regional accessibility, the urban area of Lindian County is segmented into 3 resident disaster prevention life circles and 24 emergency disaster prevention life circles. The objective of this study is to optimize shelter siting and establish disaster prevention life circles in diverse urban areas. This endeavor aims to bolster urban resilience and foster sustainable urban development.

Vector-Based Realization of Area-Weight Proportional Multiplicatively Weighted Voronoi Diagrams With the ArcGIS Engine

In the geographical field, the studies have been on service areas using the Voronoi diagram and its derived models is extensive, but there is a lack of effective methods to achieve a good area-weight proportionality between generators and their exclusive regions. As a famous visualizing method, adaptive multiplicatively weighted Voronoi diagrams are able to achieve it, but are limited to displaying non-spatial data. The approach of the area-weight proportional multiplicatively weighted Voronoi diagram is proposed to solve these problems by allowing for spatial division with a point-fixed iteration approach and a vector-based multiplicatively weighted Voronoi diagram construction method from point features with spatial coordinates and references in GIS environments. It enables one to create a set of regions that is proportional to the weights of the generators. The method is successfully tested on a series of cases. The approach aims to establish a kind of spatial data model to represent demand and supply situations in real life.

Site selection and capacity determination of charging stations considering the uncertainty of users’ dynamic charging demands

Aiming at the problems of high investment and low efficiency in the planning and construction of electric vehicle (EV) charging stations in cities, an optimization model for site selection and capacity determination of charging stations considering the uncertainty of users’ dynamic charging demands is proposed. Firstly, based on the travel chain theory and the Origin-Destination (OD) matrix, the travel characteristics of EVs are studied, and the spatial and temporal distribution prediction model of EV charging load is established through the dynamic Dijkstra algorithm combined with the Monte Carlo method. Secondly, a site selection model for the charging station is established which takes the minimum annualized cost of the charging station operator and the annualized economic loss of the EV users as the goal. At the same time, the weighted Voronoi diagram and Adaptive Simulated Annealing Particle Swarm Optimization algorithm (ASPSO) are adopted to determine the optimal number/site selection and service scope of charging stations. Finally, an uncertain scenario set is introduced into the capacity determination model to describe the uncertainty of the users’ dynamic charging demands, and the robust optimization theory is utilized to solve the capacity of the charging station. A case study is carried out for the EV charging station planning problem in some urban areas of a northern city, and the validity of the model is verified.

Evaluation of route choice for walking commutes to school and street space optimization in old urban areas of China based on a child‐friendly orientation: The case of the Wuyi Park area in Zhengzhou

AbstractWalking to school promotes the health of school‐aged children. The safety and comfort of the walking environment are lacking in China due to the prioritization of motorized traffic. This paper focuses on the choice of walking routes for school‐aged children commuting in old urban areas of China. A walking route choice model is constructed by combining a weighted Voronoi diagram and the closest facility analysis in ArcMap. The walking route choices of school‐aged children from home to school and the flows along routes are analysed. Based on the model results, targeted design suggestions for updating existing street spaces are proposed.

Examining Changes in Consumer Spatial Structure and Sustainable Development Issues in Beijing before and after the Outbreak of COVID-19

Urban consumption spatial structure has a direct impact on the sustainable development and quality of life of urban residents. This study investigates the impact of COVID-19 on Beijing’s urban consumption spatial structure within the Sixth Ring Road. Utilizing POI (Point of Interest) data and the Kernel Density method, the spatial distribution of commercial centers is analyzed. Consumption data from China UnionPay for 2019 and 2020, along with the Weighted Voronoi diagram method, are employed to assess changes in the radiation range of commercial centers. The findings indicate that: (1) owing to the pandemic’s repercussions, commercial centers at different levels and locations have different changes. (2) There is an overarching decline in UnionPay consumer spending across diverse streets in Beijing. (3) Following the epidemic, large-scale consumption hubs have maintained their dominance, ensuring the overall stability of the city’s consumption spatial pattern. In conclusion, the changes in commercial centers and the significant decrease in consumer spending underscore the dynamic interplay between urban consumption and external shocks like the pandemic. These insights are crucial for urban planning strategies aiming to enhance both resilience and sustainability in the face of unforeseen challenges. The spatial restructuring of traditional commercial centers requires nuanced urban planning. Recognizing the resilience and expansion of smaller centers suggests the importance of fostering localized economic activities. Policymakers could incentivize their development to promote community engagement and economic sustainability.

Research on Spatial Restructuring of Farmers’ Homestead Based on the “Point-Line-Surface” Characteristics of Mountain Villages

The spatial restructuring of rural settlements is conducive to the realization of rural transition and development. This study constructed a “point-line-surface” framework for the spatial reconstruction of the homestead in a typical mountain village and used the weighted Voronoi diagram and buffer analysis method to analyze. The results are as follows. (1) The development capacity of rural homesteads in Longfeng Village was divided into three levels: high, medium, and low. Among them, the high-level homesteads clustered in the north and south of the village in the form of a “T” and a long strip, respectively; the medium-level homesteads are mostly aggregated in the middle of the village; the low-level homesteads are mainly distributed along the Fenghuang Mountain. (2) The layout of homesteads in Longfeng Village was axis-oriented, which is manifested by the number and scale being in a gradient-decreasing pattern with the main road axis as the centerline. (3) According to the principle of “maximum” development capacity of the homestead, nine reconstruction units are divided. By calculating the location entropy, it is found that the dominant functions of each reconstruction unit mainly include supporting life services, operational production, ecological agricultural production, and traditional agricultural production, and there are obvious differences in the development patterns of homesteads in different functional units. (4) Based on the “point-line-surface” characteristics of the homestead, four reconstruction modes, namely, modern community type, field and garden integration type, road-pointing type, and traditional residential type, are summarized, and the reconstruction strategies are proposed accordingly. The “point-line-surface” framework of rural settlements is of practical significance and theoretical value, which can provide a decision-making reference for the optimization and reorganization of residential land space in villages of the same type in mountain areas. Moreover, the integrated and innovative framework proposed in the paper has also international significance, thanks to the possibility of replicating the research strategy and methodological approach in other contexts.

A novel model to evaluate spatial structure in thinned conifer-broadleaved mixed natural forests

In order to ensure the effective analysis and reconstruction of forests, it is key to ensure the quantitative description of their spatial structure. In this paper, a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed. In particular, we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans. The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests. The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height. Moreover, the influence of crown length is greater than that of tree height. There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree, with an average intersection of neighboring crowns reaching 80%. The rank rating of natural forest sample plots is correlated with the optimal solution distance model, and their results are generally consistent for natural forests. However, the rank rating is not able to provide a quantitative assessment. The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands. It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point, and accurately assesses the forest spatial structure. The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.

Spatio-temporal evolution of resources and environmental carrying capacity and its influencing factors: A case study of Shandong Peninsula urban agglomeration

Promoting ecological conservation and high-quality development in the Yellow River basin is an important objective in China's 14th Five-Year Plan. Understanding the spatio-temporal evolution of and factors affecting the resources and environmental carrying capacity (RECC) of the urban agglomerations is critical for boosting high-quality green-oriented development. We first combined the Driver-Pressure-State-Impact-Response (DPSIR) framework and the improved Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) model to evaluate the RECC of Shandong Peninsula urban agglomeration in 2000, 2010 and 2020; we then used trend analysis and spatial autocorrelation analysis to understand the spatio-temporal evolution and distribution pattern of RECC. Furthermore, we employed Geodetector to detect the influencing factors and classified the urban agglomeration into six zones based on the weighted Voronoi diagram of RECC as well as specific conditions of the study area. The results show that the RECC of Shandong Peninsula urban agglomeration increased consistently over time, from 0.3887 in 2000 to 0.4952 in 2010 and 0.6097 in 2020, respectively. Geographically, RECC decreased gradually from the northeast coast to the southwest inland. Globally, only in 2010 the RECC presented a significant spatial positive correlation, and that in the other years were not significant. The high-high cluster was mainly located in Weifang, while the low-low cluster in Jining. Furthermore, our study reveals three key factors—advancement of industrial structure, resident consumption level, and water consumption per ten thousand yuan of industrial added value—that affected the distribution of RECC. Other factors, including the interactions between residents’ consumption level and environmental regulation, residents’ consumption level and advancement of industrial structure, as well as between the proportion of R&D expenditure in GDP and resident consumption level also played important roles resulting in the variation of RECC among different cities within the urban agglomeration. Accordingly, we proposed suggestions for achieving high-quality development for different zones.

Meshless power diagrams

The computation of power diagrams (or weighted Voronoi diagrams) is a fundamental task in computational geometry and computer graphics. To accomplish the computation, we provide a different way from the existing ones for lifting the weighted seeds to a set of points in the space of one dimension higher, then the power cells can be directly obtained by computing the intersections of the Voronoi cells of these lifting points and the original space. This property enables us to apply the method based on the k-nearest neighbors query to the generation of power diagrams. Each power cell is obtained by sequentially clipping the input domain using the bisectors between its seed and the k-nearest neighbors. Experimental results demonstrate that our method outperforms the state-of-the-art one based on regular triangulation in terms of efficiency for general cases in the 2D and 3D spaces.

Dynamic domain decomposition method based on weighted Voronoi diagrams

Dynamic load balancing during the high performance computing is an important part of parallel workflow. An efficient way to achieve the desired distribution of load during computation is to use the Voronoi diagram (VD) for the domain decomposition. The advantage of this approach is that it can be used in conjunction with various numerical methods and balancing strategies. Domain decomposition based on Voronoi diagrams can be used together with Eulerian meshes, Lagrangian meshes, and meshfree methods, such as molecular dynamic or smoothed-particle hydrodynamics (SPH). However, for the basic VD decomposition it may be difficult to obtain load balance when the adaptive mesh refinement (AMR) is used: because of the high heterogeneity of the load on the adapted mesh, the balancing algorithms may be unstable or have poor convergence.In the present study we propose an improvement of the ordinary VD domain decomposition method with using the weighted Voronoi diagrams. We demonstrate the possibilities of such domain decomposition to achieve a better balanced configuration on two- and three-dimensional problems using mesh configurations typical for computational fluid dynamics.

Compact storage of additively weighted Voronoi diagrams

Compact storage of additively weighted Voronoi diagrams

A willingness-aware user recruitment strategy based on the task attributes in mobile crowdsensing

With the powerful sensing, computing capabilities of mobile devices, large-scale users with smart devices throughout the city would be the perfect carrier for the people-centric scheme, namely, mobile crowdsensing. Mobile crowdsensing has become a versatile platform for many Internet of things applications in urban scenarios. So how to select the appropriate users to complete the tasks and ensure the quality of the tasks has been a huge challenge for mobile crowdsensing. In this article, we propose a willingness-aware user recruitment strategy based on the task attributes to solve this problem. First, we divide the whole sensing region based on task attributes by a weighted Voronoi diagram and conduct the assessment about the sub-regions according to several parameters, and then categorize sub-regions as hot regions and blank regions. Moreover, we analyze the influence of user willingness on user recruitment and the task completion rate and assess the coverage ability of the users. Finally, we use the greedy method to optimize the user recruitment for each task to select the most suitable users for the tasks. Simulation results show that the willingness-aware user recruitment approach can significantly improve the task completion rate and achieve higher task coverage quality compared with other algorithms.

On the recognition and reconstruction of weighted Voronoi diagrams and bisector graphs

A weighted bisector graph is a geometric graph whose faces are bounded by edges that are portions of multiplicatively weighted bisectors of pairs of (point) sites such that each of its faces is defined by exactly one site. A prominent example of a bisector graph is the multiplicatively weighted Voronoi diagram of a finite set of points which induces a tessellation of the plane into Voronoi faces bounded by circular arcs and straight-line segments. Several algorithms for computing various types of bisector graphs are known. In this paper we reverse the problem: Given a partition G of the plane into faces, find a set of points and suitable weights such that G is a bisector graph of the weighted points, if a solution exists. If G is a graph that is regular of degree three then we can decide in O(m) time whether it is a bisector graph, where m denotes the combinatorial complexity of G. In the same time we can identify up to two candidate solutions such that G could be their multiplicatively weighted Voronoi diagram. Additionally, we show that it is possible to recognize G as a multiplicatively weighted Voronoi diagram and find all possible solutions in O(mlog⁡m) time if G is given by a set of disconnected lines and circles.

Spatially explicit restructuring of rural settlements: A dual-scale coupling approach

Rapid urbanization has had a profound impact on rural socioeconomic development, which has driven the spatial restructuring of rural settlements. Numerous studies have analyzed the spatial restructuring of rural settlements, yet socioeconomic factors and their impacts on villages and rural settlements have been ignored. This paper implemented a dual-scale coupling approach to identify the restructuring direction of rural settlements in Tingzu Town, Hubei Province, China. At the village scale, a population-land-industry evaluation index system was constructed to calculate the development potential of villages. The advanced gravity model was used to measure the intervillage connections, and K-means clustering was applied to divide the village groups, both approaches were used to identify the central villages. At the patch scale, kernel density estimation and accessibility analysis were applied to identify the spatial distribution characteristics of rural settlements, and rural settlements were classified into nine types based on the analysis of density-accessibility spatial combination characteristics. Four types, including relocation and evacuation, characteristic protection, suburban integration, and agglomeration and upgrading were proposed to restructure rural settlements. The restructuring direction and strategies of each type were determined by combining the influence scope of each central village, delineated by the weighted Voronoi diagram and the actual development needs of rural settlements. This study contributes to our understanding of the relationship involved in the restructuring of rural settlements and is of great practical significance for guiding the optimization of rural settlement layouts.

Coverage Control of Mobile Robots With Different Maximum Speeds for Time-Sensitive Applications

This letter presents a coverage control algorithm for robots with different maximum speeds to effectively cover an area in terms of time of travel. In order to utilize the different speeds of the robots, the region of dominance of a robot is approximated by the set of points where the robot can arrive faster than any other robots in the team by cruising at its maximum speed. Multiplicatively weighted Voronoi diagrams are used to express these speed weighted regions of dominance of the robots. The new cost function of the system takes time instead of distance as its basis, and it is interpreted as the summation of time for robots to reach all weighted points in the coverage domain. We use a controller that drives the robots towards the weighted centroids of their cells, which locally minimizes the new cost function. The resulting final configuration of the robots is shown to provide a temporally optimal coverage instead of a spatially optimal coverage over a domain.

Multiplicatively weighted Voronoi-based sensor collaborative redeployment in software-defined wireless sensor networks

Large-scale deployment of mobile wireless sensor networks has been widely used in some dangerous and hostile urban security surveillance scenarios. As a new network architecture, software-defined networks was introduced into wireless sensor networks to form a new software-defined wireless sensor networks to solve the problem of balanced large-scale deployment of sensor networks and simplify the complexity of network management. In this article, we first develop an original confident information coverage–based multiplicatively weighted Voronoi diagram through sensor clustering and sensor collaborative sensing. And then, we propose two sensor collaborative redeployment algorithms based on the novel confident information coverage–based multiplicatively weighted Voronoi diagram and software-defined wireless sensor networks architecture to provide high-confidence coverage and improve the coverage ratio. Finally, we demonstrate the superiority of the confident information coverage–based multiplicatively weighted Voronoi diagram and the effectiveness and efficiency of our proposed algorithms via a series of experiments.

基于享乐价格-结构方程双模型的西宁城市湿地生态系统服务价值及影响因素研究

PDF HTML阅读 XML下载 导出引用 引用提醒 基于享乐价格-结构方程双模型的西宁城市湿地生态系统服务价值及影响因素研究 DOI: 10.5846/stxb202108042132 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（51669028）；中国科学院"西部青年学者"项目"青海典型城市湿地生态系统服务时空格局及其增溢机制研究"资助；青海省创新平台建设专项青海省自然地理与环境过程重点实验室（2020-ZJ-Y06） A Hedonic-Price and Structural-Equation Model based value assessment and factors of ecosystem services of urban wetlands in the Xining City Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:湿地为城市发展提供巨大的生态系统服务，但其被市场"认可"的经济价值难以准确评估。以青海省西宁市城市湿地为例，筛选房屋结构、可达性、环境、湿地等10个因子，采用享乐价格模型对110个湿地周边社区样点的因子数据（2020年）进行分析，定量分析城市湿地被市场"认可"的价值量。采用断裂点理论和加权Voronoi图模型方法等，分析了湿地生态系统服务价值的空间影响范围；构建了湿地生态系统服务价值影响因素的结构方程模型，探究了影响湿地生态系统服务价值的主要因素。结果表明：（1）2020年湟水城市湿地的总价值达到3.367亿元，约有54.3%的生态系统服务通过房产被市场转化；（2）湟水湿地单位面积的生态系统服务价值为151.916元/m2，生态系统服务价值由大到小排列：火烧沟（1.632亿元）>海湖湿地（0.710亿元）>宁海湿地（0.629亿元）>北川湿地（0.330亿元）；（3）湿地生态系统服务价值占房产总价值的比例达到2.04%，位列10个因素中的第7位；线性函数模型结果显示，购买者对湿地的边际支付意愿是0.12元/m2，即购买者愿意为房产与湿地之间的距离每缩小1m而多支付0.12元。（4）购房者对湿地生态系统服务的支付意愿主要体现在文化服务上（47.19%）。 Abstract:Wetlands provide huge ecosystem services for urban development, but its market-realized economic value is difficult to evaluate accurately. Taking the urban wetland of the Xining City as an example, this study utilized the Hedonic Price Modeling (HPM) to analyze the data from 10 selected factors, of 110 wetland-surrounding community sample sites in 2020, and quantitatively analyzed of the "realized" value of urban wetland by the market. Based on Breakpoint model and the Weighted Voronoi Diagram model method, the spatial influence range of wetland ecosystem services were analyzed. The Structural Equation Model was constructed to explore the major factors affecting wetland ecosystem service values. The results showed that:(1) in 2020, the total value of Huangshui urban wetlands reached 336.7 million yuan, and about 54.3% of the ecosystem services were transformed by the market through real estate; (2) The ecosystem service value per unit area of Huangshui Wetland was 151.916 yuan/m2. Ecosystem service value ranged from large to small as Huoshaogou Wetland (163.2 million yuan)> Haihu Wetland (71.0 million yuan)> Ninghu Wetland (62.9 million yuan)> Beichuan Wetland (33.0 million yuan); (3) The Xining urban wetland ecosystem service value accounted for 2.04% of the total value of the property, ranking 7th out of the 10 factors. Linear function model results showed that the purchaser's marginal willingness to pay to these wetlands was $ 0.12/m2. These households were willing to pay $ 0.12 more for every 1 m distance reduction between their property and these wetlands. (4) Homebuyers' willingness to pay for wetland ecosystem services was mainly reflected in cultural services (47.19%). 参考文献 相似文献 引证文献

Simulation of Permeation of Saturated Cement Paste Based on a New Meso-scale Pore Network Model

This paper presents the simulation of the permeation of saturated cement paste based on a novel pore network model. First, a 2D hydration model of cement particles was developed by extending the work of Zheng et al. 2005 to provide the background for the network construction. Secondly, the establishment of the pore network model and simulation of permeation of saturated cement paste were carried out. The irregular pores between any two hydrated cement particles were linearized with clear distances as the diameters of pores. The straight tubular pores were interconnected with one another to form the network model. During this process, the weighted Voronoi diagram was employed to operate on the graphical expression of the hydrated cement particles. Water permeation in saturated cement paste was simulated to verify the pore network model. Finally, the factors including water–cement ratio, reaction temperature, reaction time and cement particle size that would influence water permeation were numerically investigated.

Analysis of the spatial range of service and accessibility of hospitals designated for coronavirus disease 2019 in Yunnan Province, China

COVID-19 poses a major threat to global health care systems, and the recent surge in mortality rates confirms the importance of timely access to care. The capacity of medical service providers is reflected both in the spatial accessibility of medical institutions and in the spatial scope of their services. Therefore, this study aims to investigate the spatial scope of services and spatial accessibility of COVID-19-designated hospitals in Yunnan Province, China. Data are collected from multiple sources and included COVID-19 case data, road data, and data from designated hospitals for COVID-19 in Yunnan Province. The optimal spatial service range for designated hospitals is delineated using a weighted Voronoi diagram that takes into account the number of medical staff and the number of beds in the hospital. Traffic accessibility coefficients are introduced to analyze the spatial accessibility of COVID-19-designated hospitals, and the spatial accessibility of each designated hospital is visualized using the inverse distance weighting interpolation algorithm. The results show the following: (1) COVID-19 cases in Yunnan Province are concentrated in the central and northern regions. The largest single cells in the weighted Voronoi diagram are mainly Pu'er (59168 km2), Honghe (35569 km2), and Baoshan (46795 km2), and the time cost of attainting medical treatment is greater for residents in marginal areas. (2) Within the service space of designated hospitals, 90.24% of patients could obtain medical assistance within 2 h. Those in 52 (36.36%) counties within a municipal jurisdiction could obtain medical services within 2 h, and 76.47% of counties have above-average spatial accessibility. (3) Medical resources in Yunnan Province should be shifted toward the high-risk east-central region and the less spatially accessible in southern and western regions.