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The effect of topographic density variations on the geoid and orthometric heights in Hong Kong

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geodesy and geodynamics 2024年第5期15卷 495-503页

作者： Albertini Nsiah Ababio department of Land Surveying and geo-informatics Hong Kong Polytechnic UniversityHong KongChina

Utilizing the adopted average topographic density of 2670 kg/m^(3)in the reduction of gravity anomalies introduces errors attributed to topographic density variations,which consequently affect geoid modeling ***,the mean gravity along the plumbline within the topography in the definition of Helmert orthometric heights is computed approximately by applying the Poincar e-Prey gravity reduction where the topographic density variations are *** Helmert orthometric heights of benchmarks are then affected by *** errors could be random or systematic depending on the specific geological setting of the region where the leveling network is physically established and/or the geoid model is *** example of systematic errors in orthometric heights can be given for large regions characterized by sediment or volcanic deposits,the density of which is substantially lower than the adopted topographic density used in Helmert's definition of *** same applies to geoid modeling *** this study,we investigate these errors in the Hong Kong territory,where topographic density is about 20%lower than the density of 2670 kg/m^(3).We use the digital rock density model to estimate the effect of topographic density variations on the geoid and orthometric *** results show that this effect on the geoid and Helmert orthometric heights reach maxima of about 2.1 and 0.5 cm,*** results provide clear evidence that rock density models are essential in physical geodesy applications involving gravimetric geoid modeling and orthometric height determination despite some criticism that could be raised regarding the reliability of these density ***,in regions dominated by sedimentary and igneous rocks,the geological information is essential in these applications because topographic densities are substantially lower than the average density of 2670 kg/m^(3),thus introducing large systematic errors in geoid and orthometric

关键词： Rock density geoid Topography Heights Leveling network

Comparative Analysis of Metro Passengers’Mobility Patterns and Jobs-housing Balance of Metropolitan

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Journal of geodesy and geoinformation Science 2024年第2期7卷 1-17页

作者： HUANG Yiman ZHANG Anshu SU Yuezhu SHI Wenzhong department of Land Surveying and geo-informatics The Hong Kong Polytechnic UniversityHong Kong 999077China Otto Poon Charitable Foundation Smart Cities Research Institute and department of and Land Surveying and geo-informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

The advent of the big data era has provided many types of transportation datasets,such as metro smart card data,for studying residents’mobility and understanding how their mobility has been shaped and is shaping the urban *** this paper,we use metro smart card data from two Chinese metropolises,Shanghai and *** metro mobility indicators are introduced,and association rules are established to explore the mobility *** proportion of people entering and exiting the station is used to measure the jobs-housing *** is found that the average travel distance and duration of Shanghai passengers are higher than those of Shenzhen,and the proportion of metro commuters in Shanghai is higher than that of *** jobs-housing spatial relationship in Shenzhen based on metro travel is more balanced than that in *** fundamental reason for the differences between the two cities is the difference in urban *** with the monocentric structure of Shanghai,the polycentric structure of Shenzhen results in more scattered travel hotspots and more diverse travel routes,which helps Shenzhen to have a better jobs-housing *** paper fills a gap in comparative research among Chinese cities based on transportation big data *** results provide support for planning metro routes,adjusting urban structure and land use to form a more reasonable metro network,and balancing the jobs-housing spatial relationship.

关键词： metro smart card data mobility patterns association rules jobs-housing balance

Hybrid pedestrian positioning system using wearable inertial sensors and ultrasonic ranging

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Defence Technology（防务技术） 2024年第3期33卷 327-338页

作者： Lin Qi Yu Liu Chuanshun Gao Tao Feng Yue Yu School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China department of Land Surveying and geo-informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,*** performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration *** paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint *** addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial ***,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall *** results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.

关键词： Pedestrian positioning system Wearable inertial sensors Ultrasonic ranging Deep-learning Data and model dual-driven

Reassessing the contributions of terrestrial waters to sea level variations in the South China Sea and its response to alternating ENSO events

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Science China Earth Sciences 2024年第7期67卷 2253-2267页

作者： Pengfei YANG Hok Sum FOK Zhongtian MA MOE Key Laboratory of geospace Environment and geodesy&MNR Key Laboratory of geophysical geodesy School of Geodesy and GeomaticsWuhan UniversityWuhan 430079China Hubei Luojia Laboratory Wuhan 730079China department of Land Surveying and geo-informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

Regional sea level variability is linked to regional terrestrial water and the El Ni?o-Southern Oscillation(ENSO).This study assessed the relationships between the sea level variations in the South China Sea(SCS)and ENSO,the impact of terrestrial water storage(TWS)on non-steric sea level(NSSL),and the contributions of steric sea level(SSL)and NSSL to sea level anomaly(SLA),*** 2003 to 2015,the SLAs exhibited a long-term trend of 6.65±0.78 mm/yr,which was primarily attributed to the ***,during 2003-2015,ENSO events alternating with varying intensities might also be responsible for the unusually high SLA *** to the SSLs,the NSSLs contributed the seasonal signals to the SLAs,while the NSSLs changes were largely explained by the TWS in the Mekong River Basin at the seasonal scale and in the Pearl River Basin and Red River Basin at other time *** contrast to the TWS,the contributions of precipitation and evapotranspiration were relatively minor.A negative correlation between the sea level variations and ENSO was also found,with cross-correlation coefficients between the oceanic Ni?o index and SLAs/SSLs/NSSLs of -0.36/-0.37/-0.62 with lags of 2/3/2 months,*** findings systematically reassessed the contributions of different components to the sea level *** study provided a benchmark for in-depth analysis of the impacts of terrestrial water and other potential causes on sea level rise in the SCS.

关键词： South China Sea Sea level variations Terrestrial water storage ENSO

A joint model of infrastructure planning and smart charging strategies for shared electric vehicles

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Green Energy and Intelligent Transportation 2024年第4期3卷 44-58页

作者： Junbei Liu Xiong Yang Chengxiang Zhuge department of Land Surveying and geo-informatics The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina The Hong Kong Polytechnic University Shenzhen Research Institute ShenzhenChina Smart Cities Research Institute The Hong Kong Polytechnic UniversityHong KongChina

This paper presents a data-driven joint model designed to simultaneously deploy and operate infrastructure for shared electric vehicles(SEVs).The model takes into account two prevalent smart charging strategies:the Time-of-Use(TOU)tariff and Vehicle-to-Grid(V2G)*** specifically quantify infrastructural demand and simulate the travel and charging behaviors of SEV users,utilizing spatiotemporal and behavioral data extracted from a SEV trajectory *** findings indicate that the most cost-effective strategy is to deploy slow chargers exclusively at rental *** SEV operators,the use of TOU and V2G strategies could potentially reduce charging costs by 17.93%and 34.97%*** the scenarios with V2G applied,the average discharging demand is 2.15kWh per day per SEV,which accounts for 42.02%of the actual average charging demand of *** findings are anticipated to provide valuable insights for SEV operators and electricity companies in their infrastructure investment decisions and policy formulation.

关键词： Electric carsharing Charging infrastructure Smart charging Big data Micro-simulation

Detecting Malicious Uniform Resource Locators Using an Applied Intelligence Framework

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Computers, Materials & Continua 2024年第6期79卷 3827-3853页

作者： Simona-Vasilica Oprea Adela Bara department of Economic informatics and Cybernetics Bucharest University of Economic StudiesBucharest010572Romania

The potential of text analytics is revealed by Machine Learning(ML)and Natural Language Processing(NLP)*** this paper,we propose an NLP framework that is applied to multiple datasets to detect malicious Uniform Resource Locators(URLs).Three categories of features,both ML and Deep Learning(DL)algorithms and a ranking schema are included in the proposed *** apply frequency and prediction-based embeddings,such as hash vectorizer,Term Frequency-Inverse Dense Frequency(TF-IDF)and predictors,word to vector-word2vec(continuous bag of words,skip-gram)from Google,to extract features from ***,we apply more state-of-the-art methods to create vectorized features,such as ***,feature engineering that is specific to URL structure is deployed to detect scams and other *** framework assessment,four ranking indicators are weighted:computational time and performance as accuracy,F1 score and type error *** the computational time,we propose a new metric-Feature Building Time(FBT)as the cutting-edge feature builders(like doc2vec or GloVe)require more *** applying the proposed assessment step,the skip-gram algorithm of word2vec surpasses other feature builders in ***,eXtreme Gradient Boost(XGB)outperforms other *** this setup,we attain an accuracy of 99.5%and an F1 score of 0.99.

关键词： Detecting malicious URL classifiers text to feature deep learning ranking algorithms feature building time

Solute flow and particle transport in aquatic ecosystems: A review on the effect of emergent and rigid vegetation

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Environmental Science and Ecotechnology 2024年第5期21卷 77-91页

作者： Judy Q.Yang St.Anthony Falls Laboratory Department of CivilEnvironmentaland Geo-EngineeringUniversity of Minnesota Twin CitiesMNUSA

In-channel vegetation is ubiquitous in aquatic environments and plays a critical role in the fate and transport of solutes and particles in aquatic *** studies have advanced our understanding of the role of vegetation in solute flow and particle transport in aquatic *** review summarizes these papers and discusses the impacts of emergent and rigid vegetation on the surface flow,the advection and dispersion of solutes,suspended load transport,bedload transport,and hyporheic *** two competing effects of emergent vegetation on the above transport processes are *** the one hand,emergent vegetation reduces mean flow velocity at the same surface slope,which reduces mass *** the other hand,at the same mean flow velocity,vegetation generates turbulence,which enhances mass *** understanding of these two competing effects and predictive equations derived from laboratory experiments are *** equations for the mean flow velocity and turbulent kinetic energy inside an emergent vegetation canopy are derived based on force and energy *** impacts of emergent vegetation on the advection-dispersion process,the suspended load and bedload transport,and the hyporheic exchange are *** impacts of other vegetation-related factors,such as vegetation morphology,submergence,and flexibility,are briefly *** role of vegetation in transporting other particles,such as micro-and macro-plastics,is also briefly ***,suggestions for future research directions are proposed to advance the understanding of the dynamic interplays among natural vegetation,flow dynamics,and sedimentary processes.

关键词： transport load flow

Factors Impacting Participatory Post‑Disaster Relocation and Housing Reconstruction:The Case of Tsholotsho District,Zimbabwe

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International Journal of Disaster Risk Science 2024年第1期15卷 58-72页

作者： Nombulelo Kitsepile Ngulube Hirokazu Tatano Subhajyoti Samaddar department of Social informatics Graduate School of InformaticsKyoto UniversityKyoto 606-8507Japan Disaster Prevention Research Institute(DPRI) Kyoto UniversityKyoto 611-0011Japan

Relocation is not typically considered the best planning option for post-disaster reconstruction and rehabilitation,but it may be necessary if the site has suffered severe damage or is at imminent *** is a growing recognition that strong community participation is necessary in the post-disaster relocation decision-making process since relocation can have detrimental effects on a community’s livelihood,cultural system,and way of life,among ***,the realization of this still needs to be *** of yet,few studies have examined a comprehensive account of meaningful community engagement in post-disaster relocation and reconstruction,particularly in developing *** study investigated what factors influenced local communities’ participation in post-disaster relocation and reconstruction works after the 2017Cyclone Dineo flood disaster in the Tsholotsho District of *** research methods such as face-to-face interviews,observations,and focus groups were used to collect qualitative data from a purposive sample of 25 community members and 6 *** empirical investigation showed that despite the fact that the relocation project was conceived as a community-centered project,there was no meaningful community engagement,due to the absence of a participatory framework or planning guidelines for stakeholder engagement,as well as the lack of political willingness among government *** study concluded that the lack of community involvement led to local communities abandoning the reconstruction sites because relocation projects failed to accommodate the cultural beliefs,place attachments,and livelihood concerns of local *** study suggested that it is imperative to enhance the awareness of government officials and other stakeholders about the importance of community participation for the effective implementation of post-disaster relocation *** community participation can also provide avenues fo

关键词： Community rehabilitation Housing reconstruction-Participatory relocation Zimbabwe

Assessment of SoilGrids data for soil erosion estimation at watershed scale: A case study in northern Thailand

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Pedosphere 2024年第4期34卷 797-813页

作者： Chike Onyeka MADUEKE Dhruba Pikha SHRESTHA Panagiotis NYKTAS department of Natural Resources Faculty of Geo-information Science and Earth Observation(ITC)University of TwenteEnschede 7500 AEthe Netherlands department of Applied Earth Sciences Faculty of Geo-information Science and Earth Observation(ITC)University of TwenteEnschede 7500 AEthe Netherlands department of Soil Science and Land Resources Management Nnamdi Azikiwe UniversityP.M.B.5025AwkaAnambra State 420110Nigeria

Soil erosion has been identified as one of the most destructive forms of land degradation,posing a threat to the sustainability of global economic,social and environmental *** underscores the need for sustainable land management that takes erosion control and prevention into *** requires the use of state-of-the-art erosion prediction *** models often require extensive input of detailed spatial and temporal data,some of which are not readily available in many developing countries,particularly detailed soil *** soil dataset Global Gridded Soil Information(SoilGrids)could potentially fill the data ***,its value and accuracy for soil erosion modelling in the humid tropics is still unknown,necessitating the need to assess its value vis-à-vis field-based *** major objective of this study was to conduct a comparative assessment of the value of SoilGrids and field-based soil data for estimating soil *** samples were collected from five physiographic positions(summit,shoulder,back slope,foot slope,and toe slope)using the soil catena *** were collected using a 5-cm steel sample ring(undisturbed)and a spade(disturbed).Data of the landform,predominant vegetation types,canopy cover,average plant height,land use,soil depth,shear strength,and soil color were recorded for each *** soil samples were subjected to laboratory analysis for saturated hydraulic conductivity,bulk density,particle size distribution,and organic matter *** functions were applied on the SoilGrids and field-based data to generate soil hydrological *** resultant field-based data were compared with the SoilGrids data for corresponding points/areas to determine the potential similarities of the two *** datasets were then used as inputs for soil erosion assessment using the revised Morgan-Morgan-Finney *** results from both datasets were again compared to determine the degree of *** r

关键词： hillslope modelling pedotransfer function similarity assessment soil erosion modelling soil loss soil survey