检索结果-内蒙古大学图书馆

spatial network disintegration based on spatial coverage

RELIABILITY ENGINEERING & SYSTEM SAFETY 2025年 253卷

作者： Deng, Ye Wang, Zhigang Xiao, Yu Shen, Xiaoda Kurths, Jurgen Wu, Jun Beijing Normal Univ Fac Arts & Sci Dept Syst Sci Zhuhai 519087 Peoples R China Beijing Normal Univ Int Acad Ctr Complex Syst Zhuhai 519087 Peoples R China Beijing Normal Univ Sch Syst Sci Beijing 100875 Peoples R China Potsdam Inst Climate Impact Res Res Domain Complex Sci D-14473 Potsdam Germany Humboldt Univ Dept Phys D-12489 Berlin Germany

The problem of network disintegration, such as interrupting rumor spreading networks and dismantling terrorist networks, involves evaluating changes in network performance. However, traditional metrics primarily focus on the topological structure and often neglect the crucial spatial attributes of nodes and edges, thereby failing to capture the spatial functional losses. Here we first introduce the concept of spatial coverage to evaluate the spatial network performance, which is defined as the convex hull area of the largest connected component. Then a greedy algorithm is proposed to maximize the reduction of the convex hull area through strategic node removals. Extensive experiments verified that the spatial coverage metric can effectively quantify changes in the performance of spatial networks, and the proposed algorithm can maximize the reduction of the convex hull area of the largest connected component compared to genetic algorithm and centrality strategies. Specifically, our algorithm reduces the convex hull area by up to 30% compared to the best-performing strategy. These results indicate that the critical nodes influencing network performance are a combination of numerous peripheral spatial leaf nodes and a few central spatial core nodes. This study substantially enhances our understanding of spatial network robustness and provides a novel perspective for network optimization.

关键词： spatial network Network disintegration Network performance spatial coverage Greedy algorithm Critical nodes

来源：评论

学校读者我要写书评

暂无评论

coverage vs frequency: Is spatial coverage or temporal frequency more impactful on transit ridership?

引用

JOURNAL OF TRANSPORT GEOGRAPHY 2025年 122卷

作者： Lyons, Torrey Ewing, Reid Tian, Guang Idaho Natl Lab 1955 Fremont Ave Idaho Falls ID 83415 USA Univ Utah Coll Architecture Planning 375 South 1530 East RM 235 AAC Salt Lake City UT 84112 USA Univ New Orleans Ctr Equitable Transit Oriented Communities Dept Planning & Urban Studies 378 Milneburg Hall2000 Lakeshore Dr New Orleans LA 70184 USA

Transit ridership has long been studied, and the findings are elucidated by Taylor and Fink (2003) when they say, "to sum, transit ridership is largely, though not completely, a product of factors outside the control of transit managers." Other than transit fare price, few studies have looked with much scrutiny at the factors that are within the purview of transit agencies. Transit service provision has been found to affect ridership, but "service provision" is often nebulously defined, shedding little light onto how transit managers can best provide service that will create returns in the form of transit ridership. This study examines the effects of spatial coverage and temporal frequency on transit ridership to determine just which lever is most effective. We use a cross-sectional study design with 152 regions around the United States. We employ structural equation modeling (SEM) to explain complex relationships that exist among interrelated variables. We find that both factors are strong predictors of transit ridership, with service frequency having a larger impact.

关键词： spatial coverage Temporal frequency Transit planning Performance measurement Transit ridership

来源：评论

学校读者我要写书评

暂无评论

Assessing Vertical Accuracy and spatial coverage of ICESat-2 and GEDI Spaceborne Lidar for Creating Global Terrain Models

引用

REMOTE SENSING 2024年第13期16卷 2259-2259页

作者： Pronk, Maarten Eleveld, Marieke Ledoux, Hugo Deltares POB 177 NL-2600 MH Delft Netherlands Delft Univ Technol Fac Architecture & Built Environm POB 5 NL-2600 AA Delft Netherlands

Digital Elevation Models (DEMs) are a necessity for modelling many large-scale environmental processes. In this study, we investigate the potential of data from two spaceborne lidar altimetry missions, ICESat-2 and GEDI-with respect to their vertical accuracies and planimetric data collection patterns-as sources for rasterisation towards creating global DEMs. We validate the terrain measurements of both missions against airborne lidar datasets over three areas in the Netherlands, Switzerland, and New Zealand and differentiate them using land-cover classes. For our experiments, we use five years of ICESat-2 ATL03 data and four years of GEDI L2A data for a total of 252 million measurements. The datasets are filtered using parameter flags provided by the higher-level products ICESat-2 ATL08 and GEDI L3A. For all areas and land-cover classes combined, ICESat-2 achieves a bias of -0.11 m, an MAE of 0.43 m, and an RMSE of 0.93 m. From our experiments, we find that GEDI is less accurate, with a bias of 0.09 m, an MAE of 0.98 m, and an RMSE of 2.96 m. Measurements in open land-cover classes, such as "Cropland" and "Grassland", result in the best accuracy for both missions. We also find that the slope of the terrain has a major influence on vertical accuracy, more so for GEDI than ICESat-2 because of its larger horizontal geolocation error. In contrast, we find little effect of either beam power or background solar radiation, nor do we find noticeable seasonal effects on accuracy. Furthermore, we investigate the spatial coverage of ICESat-2 and GEDI by deriving a DEM at different horizontal resolutions and latitudes. GEDI has higher spatial coverage than ICESat-2 at lower latitudes due to its beam pattern and lower inclination angle, and a derived DEM can achieve a resolution of 500 m. ICESat-2 only reaches a DEM resolution of 700 m at the equator, but it increases to almost 200 m at higher latitudes. When combined, a 500 m resolution lidar-based DEM can be achieved globally

关键词： ICESat-2 ATL03 GEDI L2A DTM lidar altimetry validation laser terrain vertical accuracy spatial coverage global

来源：评论

学校读者我要写书评

暂无评论

WSPTGAN for Global Ocean Surface Wind Speed Generation With High Temporal Resolution and spatial coverage

引用

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2024年 62卷 1页

作者： Li, Menglong Hou, Yonghong Song, Xiaowei Hou, Chunping Wang, Zhipeng Xiong, Zixiang Ma, Dan Tianjin Univ Sch Elect & Informat Engn Tianjin 300072 Peoples R China Zhongyuan Univ Technol Sch Informat & Commun Engn Sch Elect & Informat Engn Zhengzhou 450007 Henan Peoples R China China Elect Power Res Inst CEPRI Beijing 100000 Peoples R China Texas A&M Univ Dept Elect & Comp Engn College Stn TX 77843 USA

Obtaining global ocean surface wind speed data with high temporal resolution and spatial coverage is a challenging task. Due to the lack of widely applicable direct measurement methods and algorithms, current research and data products can only achieve good performance in a small spatial range or at low temporal resolution. In this article, a generative adversarial network (GAN) with a transformer structure called Wind Speed Prediction transformer-GAN (WSPTGAN) is proposed to generate wind speed data with good spatial coverage and high temporal resolution for areas. The WSPTGAN is trained with the proposed image-like wind speed data combined partial missing dataset (CPMD), which is combined with the fifth generation of the European Center for Medium-Range Weather Forecast (ECMWF) reanalysis data and Advanced Scatterometer (ASCAT) data from Meteorological Operational satellites. Thanks to the defective data learning mechanism (DDLM), sequential-wise multihead self-attention mechanism (SMSM), and sequence feature adaptive verification mechanism (SFAVM) in the proposed algorithm, the obtained model has good wind speed prediction accuracy with root mean square error (RMSE) of 0.8984 m/s and can achieve multistep 10-min wind speed data generation within the global ocean. After comparison with five state-of-the-art prediction models, it is confirmed that the algorithm in this article is able to make better use of the defective data for learning and prediction of wind field trends in global ocean regions.

关键词： Defective data self-attention spatial coverage temporal resolution transformer wind speed

来源：评论

学校读者我要写书评

暂无评论

A spatial coverage-Based Participant Recruitment Scheme for Mobile Crowdsourcing

引用

HUMAN-CENTRIC COMPUTING AND INFORMATION SCIENCES 2023年 13卷

作者： Yang, Jian Zhang, Di Hu, ChunMei Wang, KaiXuan Shanxi Univ Finance & Econ Sch Informat Taiyuan Peoples R China Jiangsu Coll Nursing Modern Educ Technol Ctr Huaian Peoples R China Qufu Normal Univ Sch Cyber Sci & Engn Qufu Peoples R China

A revolutionary distributed problem-solving model is being enabled by the increasing proliferation of mobile smart devices, namely mobile crowdsourcing, which employs ubiquitous mobile users to gather and analyze data beyond what was traditionally possible, while becoming a leading area for study in both academia and industry. However, how to recruit participants to provide high quality data with a limited budget is challenging for a crowdsourcing system. In contrast to traditional fixed sensors, participants are the general population with smart devices, which boast the unique advantage of predictable mobility. To address this problem, this article first studies the relationship between predictable mobility and spatial coverage, and proposes a new strategy to recruit the optimal subset of participants by jointly considering their current and future locations with the aim of ensuring that the recruited participants can provide high coverage sensory data. Secondly, participant recruitment proves to be a NP-hard problem, while a harmony search algorithm with annealing randomness (HSA-AR) is proposed as a trade-off between the quality of problem-solving and the computation time. Finally, through extensive simulations utilizing real-world and synthetic datasets, we demonstrate that HSA-AR outperforms other baseline methods under various settings.

关键词： Mobile Crowdsourcing Participant Recruitment spatial coverage NP-Hard HSA-AR

来源：评论

学校读者我要写书评

暂无评论

Decadal changes in the spatial coverage of Zostera noltei in two seagrass meadows (Ria de Vigo;NW Spain)

引用

REGIONAL STUDIES IN MARINE SCIENCE 2020年 36卷

作者： Roman, M. Fernandez, E. Zamborain-Mason, J. Martinez, L. Mendez, G. Univ Vigo Fac Marine Sci Ctr Marine Res Campus Univ Lagoas Marcosende Vigo 36310 Spain James Cook Univ ARC Ctr Excellence Coral Reef Studies Townsville Qld Australia

Seagrass meadows are influenced by anthropogenic activities occurring in the littoral, generally resulting in an intense regression in the last decades. This study examines the evolution of the Z. noltei coverage from 1989 to 2014 in two seagrass meadows located in the Ria de Vigo (Arcade and A Ramallosa), subjected to different degrees of coastline alteration, anthropogenic land cover, population growth and shellfishing activity. A spatial analysis of the distribution of Z. noltei was carried out using aerial photographs from 1989, 2004 and 2014 and field surveys. The results obtained showed that in Arcade, a meadow characterized by low watershed-scale anthropogenic pressure and absence of shellfishing on the seagrass, the Z. noltei coverage decreased by 48 % in the studied period. By contrast, in A Ramallosa, a meadow characterized by moderately watershed-scale anthropogenic pressure and presence of shellfishing on the seagrass, the Z. noltei coverage increased by 56%. The observed increase of Z. noltei coverage in A Ramallosa appears to be related to the combined effect of increase of finer sediment loads and a decrease of bivalve harvesting. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Seagrass spatial coverage Anthropogenic pressure Bivalve harvesting CORINE Land cover

来源：评论

学校读者我要写书评

暂无评论

Six scooter operators, six maps: spatial coverage and regulation of micromobility in Vienna, Austria

引用

CASE STUDIES ON TRANSPORT POLICY 2020年第2期8卷 658-671页

作者： Moran, Marcel E. Laa, Barbara Emberger, Guenter Univ Calif Berkeley Dept City & Reg Planning Berkeley CA 94720 USA Vienna Univ Technol Res Ctr Transport Planning & Traff Engn Inst Transportat Vienna Austria

Background and objective: Electric scooters in shared schemes bring benefits to users in the form of on-demand, point-to-point transport, but pose new challenges for municipal regulation, including access issues related to their geographic availability. The size and position of the geographic service areas, or 'geofences' of scooter-sharing schemes determine where users can locate vehicles to begin a ride and park them to conclude one. The purpose of this study is to understand the spatial variance in scooter geofences in Vienna, Austria and how those differences relate to existing municipal regulations, as well as what may be learned from this case for the benefit of cities worldwide which are also grappling with this mobility trend. Methods: Over the course of one summer, all scooter geofences and no-parking zones for the six operators in Vienna were tracked via smartphone applications and manually digitized on a weekly basis. This enables spatial analyses across scooter operators, and sheds light on such issues as differences in geofence size, shape, and placement, no-parking zone categories, and the frequency of geofence modification. Results: Across the six scooter operators in Vienna, geofence coverage differed sharply over this time period, as did where scooter parking was prohibited (via no-parking zones). Categorization of no-parking zones indicate that the bulk are located around parks, pedestrianized corridors, and cultural institutions. Moreover, all six scooter operators modified their geofences during the course of this study (adding neighborhoods and removing others), which took place without any type of municipal approval or standardized disclosure to users. Four operators expanded their geofences, while two contracted them. Conclusion: These observations combine to establish a scooter-sharing profile of Vienna (matching regulations against spatial outcomes) that can serve as the basis for future comparison cases worldwide. Moreover, they indicate th

关键词： Dockless scooters E-scooters Urban transport Geofences spatial coverage

来源：评论

学校读者我要写书评

暂无评论

An Analysis of Spatiotemporal Baseline and Effective spatial coverage for Lunar-Based SAR Repeat-Track Interferometry

引用

IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2019年第9期12卷 3458-3469页

作者： Dong, Jinglong Shen, Qiang Jiang, Liming Jiang, Houjun Li, Dewei Wang, Hansheng Mao, Song Chinese Acad Sci Inst Geodesy & Geophys State Key Lab Geodesy & Earths Dynam Wuhan 430077 Hubei Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Nanjing Univ Posts & Telecommun Dept Surveying & Geoinformat Nanjing 210023 Jiangsu Peoples R China

Lunar-based synthetic aperture radar repeat-track interferometry (LB-SAR RTI) is expected to play a significant role in addressing science issues pertaining to Earth dynamics because of its large-scale, long-term, and stable Earth observation (EO) ability. The distribution of the spatiotemporal baseline and effective spatial coverage are of great importance in the observation mode design and data acquisitions plan of LB-SAR RTI. Here, we describe the observation geometry and present the calculation method of the spatiotemporal baseline and effective spatial coverage of LB-SAR RTI. Using the Jet Propulsion Laboratory DE430 ephemeris, the results show that, first, the 1, 26, and 27 repeat cycles temporal baselines have the highest number of effective interferometric combinations, accounting for 50% of the effective observations;second, the optimal temporal baselines of LB-SAR RTI for large-scale EO are 26 and 27 repeat cycles, and the effective spatial coverage could reach up to 360 degrees x 40 degrees (longitudexlatitude) in one day;and third, LB-SAR RTI can be used to observe the Earth's surface between latitudes 80 degrees N and 80 degrees S with different frequencies of observation that reach a maximum at latitudes 40 degrees N and 40 degrees S and decrease gradually toward the polar and equator regions. The lunar-based observation plan should take into account the initial observation time, temporal baseline, and effective spatial coverage.

关键词： Lunar-based synthetic aperture radar (LB-SAR) repeat-track interferometry (RTI) spatial coverage spatiotemporal baseline

来源：评论

学校读者我要写书评

暂无评论

spatial coverage Measurement of Geo-Tagged Visual Data: A Database Approach 4

Spatial Coverage Measurement of Geo-Tagged Visual Data: A Da...

引用

4th IEEE International Conference on Multimedia Big Data (BigMM)

作者： Alfarrarjeh, Abdullah Kim, Seon Ho Deshmukh, Akshay Rajan, Shivnesh Lu, Ying Shahabi, Cyrus Univ Southern Calif Integrated Media Syst Ctr Los Angeles CA 90089 USA

ISBN: (纸本)9781538653210

Due to the popularity of GPS-equipped cameras such as smartphones, geo-tagged image datasets are widely available and they became a good source to record every corner of urban streets and to understand people's everyday life. However, even in the presence of such large visual datasets, a simple question is not yet answered about how much such data cover a certain area spatially. For example, when we have millions of geo-tagged images in San Francisco, how do we know if this dataset visually covers the city completely or not in an intuitive way? Do we have visual coverage of a specific region from all directions or from only a certain direction? This paper provides an answer to such a question by introducing new measurement models to collectively quantify the spatial and directional coverage of a geo-tagged image dataset for a given geographical region. Our experimental results using large real datasets demonstrate that our proposed models are able to well represent the spatial coverage of a geo-tagged image dataset, which is comparable to human perception.

关键词： geo-tagged image spatial coverage field of view directional coverage

来源：评论

学校读者我要写书评

暂无评论

Remote Sensing-Guided Sampling Design with Both Good spatial coverage and Feature Space coverage for Accurate Farm Field-Level Soil Mapping

引用

REMOTE SENSING 2019年第16期11卷 1946-1946页

作者： Wang, Yongji Jiang, Lili Qi, Qingwen Liu, Ying Wang, Jun Chinese Acad Sci Inst Geog Sci & Nat Resources Res State Key Lab Resources & Environm Informat Syst Beijing 100101 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Shandong Univ Sci & Technol Coll Geometr Qingdao 266590 Shandong Peoples R China

With the increasing requirements of precision agriculture for massive and various kinds of data, remote sensing technology has become indispensable in acquiring the necessary data for precision agriculture. Understanding the spatial variability of a target soil variable (i.e., soil mapping) is a critical issue in solving many agricultural problems. Field sampling is one of the most commonly used technologies for soil mapping, but sample sizes are restricted by resources, such as field labor, soil physicochemical analysis, and funding. In this paper, we proposed a sampling design method with both good spatial coverage and feature space coverage to achieve more precise spatial variability of farm field-level target soil variables for limited sample sizes. The proposed method used the super-grid to achieve good spatial coverage, and it took advantage of remote sensing products that were highly correlated with the target soil property (SOM content) to achieve good feature space coverage. For the experiments, we employed the ordinary kriging (OK) method to map the soil organic matter (SOM) content. The different sized super-grid comparison experiments showed that the 400 x 400 m(2) super-grid had the highest SOM content mapping accuracy. Then, we compared the proposed method to regular grid sampling (good spatial coverage) and k-means sampling (good feature space coverage), and the experimental results indicated that the proposed method had greater potential in the selection of representative samples that could improve the SOM content mapping accuracy.

关键词： soil sampling spatial coverage feature coverage farm field-level soil mapping super-grid limited sample size

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：