Dear Editor,Pose graph optimization(PGO)is a popular optimization approach that plays a crucial role in the simultaneous localization and mapping(SLAM)back-end.However,when incorrect loop closure constraints(referred ...Dear Editor,Pose graph optimization(PGO)is a popular optimization approach that plays a crucial role in the simultaneous localization and mapping(SLAM)back-end.However,when incorrect loop closure constraints(referred to as outliers)are present in the SLAM front-end,the standard PGO algorithm fails catastrophically and can not return an accurate map.To address this issue,this letter proposes a novel algorithm that leverages classical optimization methods to effectively handle outliers.The proposed algorithm introduces a new formulation that incorporates a credibility factor model,which improves the robustness of the optimization process.Additionally,an innovative consistency classification algorithm is developed to detect outliers.Extensive experiments are conducted on multiple benchmark datasets to evaluate the consistency and accuracy of the proposed algorithm.展开更多
Cropland abandonment has been a widespread phenomenon in mountainous areas due to the increasing number of natural disasters and the massive migration of rural labor in the process of rapid urbanization.Land transfer ...Cropland abandonment has been a widespread phenomenon in mountainous areas due to the increasing number of natural disasters and the massive migration of rural labor in the process of rapid urbanization.Land transfer is a crucial prerequisite for ensuring food security and fostering rural revitalization.How to promote land transfer in mountainous areas remains a challenging but important task.Nevertheless,there is a dearth of research examining land transfers among farm households that specifically address mountainous regions,and the influence of grassroots governance and geographic location has not been thoroughly elucidated within this particular context.Based on 895household samples collected in Dabie Mountainous Area in China,this study employs binary and ordinal logistic regression models to provide a more comprehensive analysis on land transfers among rural households and the determinants,including the decision to transfer land,the existence of land transfer rents,the channel of land transfer,the duration of the transfer,the pre-transfer cultivation situation,and the level of satisfaction with the land transfer rent.The findings reveal that grassroots governance,geographic location,livelihood capital,and demographic factors significantly influence land transfers among rural households.Specifically,villagers'public participation positively affects land transfer participation(β=0.235,p<0.05),while the operation of village rules and regulations negatively impacts it(β=-0.296,p<0.05).Village cadre satisfaction positively influences both land transfer rent(β=0.274,p<0.05)and rent satisfaction(β=0.303,p<0.05).Improved civil relations in the village correlate with lower land transfer rent(β=-0.511,p<0.05),while a better social atmosphere is associated with higher satisfaction with transfer rent(β=0.575,p<0.01).Households at higher elevations tend to prefer government-mediated land transfers with longer durations.The distances to the township and county centers have contrasting effects on land transfer rent,but their impacts on participation in land transfer,choice of transfer channel,and duration are consistent.The study also found that different types of livelihood capital,as well as the demographic characteristics of households,significantly affect various aspects of land transfer.These empirical findings can inform policymaking to promote more efficient land transfers in mountainous region.展开更多
The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS ...The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS factor always varies with the changing DEM resolution,i.e.,the LS factor scale effect.Previous studies have found the phenomenon of the LS factor scale effect,but the underlying causes of this phenomenon has not been well explored.Therefore,how the DEM resolution affects the LS factor and how the scale effect of the L and S factors influence the LS factor scale effect remains unclear.To address these problems,we collected 20 watersheds from the Guangdong Province with different topographic reliefs,and compared the corresponding L,S and LS factors at 10-m and 30-m resolution DEMs.Our results indicate that the S factor,heavily influenced by slope underestimation in coarse-resolution DEMs,makes a difference in the LS factor scale effect.In addition,the LS factor scale effect becomes less significant with increasing reliefs,suggesting the possibility of using 30-m DEM for LS calculation in rugged terrains.Our findings on the underlying mechanisms of the LS factor scale effect help to identify the uncertainty in the LS factor estimation,thereby enhancing the accuracy of soil erosion assessment,particularly in regions with different topographic characteristics and contribute to more effective soil conservation strategies and decision-making.展开更多
Objective:Intimate partner violence(IPV)among people living with the human immune deficiency virus(PLHIV)poses a significant threat to efforts to reduce the spread of human immune deficiency virus(HIV)and achieve the ...Objective:Intimate partner violence(IPV)among people living with the human immune deficiency virus(PLHIV)poses a significant threat to efforts to reduce the spread of human immune deficiency virus(HIV)and achieve the sustainable development goals.In Ghana,scholarly research on the forms and prevalence of IPV is available,however knowledge of the prevalence of IPV among PLHIV is limited.To understand the prevalence of IPV among PLHIV and the intersectional factors that contribute to it,this study examined the overall prevalence of IPV among PLHIV and the associated sociodemographic factors across ten regions of Ghana.Methods:We administered face-to-face survey questionnaires to 661 randomly selected antiretroviral therapy(ART)clients using Research Electronic Data Capture tools.We used descriptive statistics(mean,standard deviation,minimum,and maximum),pairwise correlation,and multivariate regression analysis to look at the data.Results:The clients of ART experienced various forms of IPV,including sexual,physical,emotional,and economic violence and controlling behaviour.The overall prevalence of IPV among PLHIV was 27.5%.This result,although on par with the global IPV average(27%),is 1.5%higher than the national rate(26%).The Upper West Region had the highest prevalence in all the categories of IPV analysed,followed by Oti Region in second place and the Upper East Region in third,except for the prevalence of sexual violence,where Greater Accra Region ranks second.In specific regions of Ghana,sociodemographic factors shaped by patriarchal and economic considerations contribute to a higher prevalence of IPV among people living with HIV.Conclusion:The findings have implications for developing policies and interventions that address the specific factors associated with HIV-induced IPV in different regions of Ghana.These interventions should also include screening PLHIV receiving ART for their IPV status regardless of gender and deploying culturally appropriate education at the community level to foster empathy towards intimate partners living with HIV.展开更多
The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by...The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.展开更多
Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the ...Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.展开更多
This study was to survey the relationship between semen values and demographics,comorbidities,and recreational substance use in a large cohort of adult men at the University of Chicago Medical Center Department of Uro...This study was to survey the relationship between semen values and demographics,comorbidities,and recreational substance use in a large cohort of adult men at the University of Chicago Medical Center Department of Urology(Chicago,IL,USA).We performed an analysis from January 2013 to December 2023 of semen samples obtained from adult patients at our institution and collected their demographics,comorbid medical conditions,and recreational substance use information.Patients were divided into categories of normozoospermia,oligozoospermia,and azoospermia on the basis of the 5th version of the World Health Organization(WHO)guidelines.Data were analyzed by univariate linear and logistic regression models,after which statistically significant variables were placed into multivariable models.Azoospermia and oligozoospermia were both associated with Caucasian or Black,Indigenous,and People of Color(BIPOC)race(both P<0.001),increasing age(P=0.005 and P<0.001,respectively),anemia(P<0.001 and P=0.02,respectively),lifetime tobacco use(both P<0.001),lifetime alcohol use(P=0.02 and P<0.001,respectively),and lifetime use of at least two recreational substances(P<0.001 and P=0.003,respectively)in multivariable models.Oligospermia was additionally associated with benign prostatic hyperplasia(BPH;P=0.003)in multivariable models.This study suggests that at-risk populations may benefit from additional early screening and workup for infertility.展开更多
Terrain can influence the spatial distribution of settlements. Studies on the terrain characteristics of settlements can help to understand the effects of the environment on human activities. This paper provides a qua...Terrain can influence the spatial distribution of settlements. Studies on the terrain characteristics of settlements can help to understand the effects of the environment on human activities. This paper provides a quantitative analysis of the relationship between settlements and topographical factors. A statistically significant sample of residential locations and ASTER GDEM V2 were used to investigate terrain traits and settlements distributions. We selected eight topographical factors and introduced a practical concept, distributive entropy, into assessing the aggregation extent of the settlements' spatial distribution. The study showed that topography varies within the study area, and distributive entropy indicates that settlements have distinctive distribution tendency in statistic approach. According to the results of this study, mountain inhabitants prefer to settle in valleys. Additionally, with distributive entropy, residential suitability was divided to three levels: suitable, normal, and unsuited. The results showed that suitable area is small in Sichuan Province, accounting for 8.2%～29.9%; however, unsuited area is large, accounting for 33%～63.3%.展开更多
The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. Th...The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.展开更多
Variability in vitamin A (VA) intake of pregnant women in Ngaoundere town according to geographic origin, socio-professional and demographic factors was studied. A total of 100 pregnant women attending ante natal visi...Variability in vitamin A (VA) intake of pregnant women in Ngaoundere town according to geographic origin, socio-professional and demographic factors was studied. A total of 100 pregnant women attending ante natal visits at the Regional Hospital in Ngaoundere were involved in the survey. A questionnaire was used to obtain information on geographic origin, socio-professional status, birth history, demographic and anthropometric factors. Dietary intake was assessed using 24-hour dietary recall. Meals potentially rich in VA consumed by these women were collected, their carotenoids contents quantified and VA activity determined by conversion. Results indicated that daily VA intake of these women varied significantly (p < 0.05) with geographic origin, level of education and age of pregnancy. VA intake of pregnant women of Northern origin (Adamawa, North and Far North Regions) was significantly (p < 0.05) lower (496 μg/day/woman) than that of women of Southern origin (588 μg/day/woman), although both were below the recommended intake of 800 μg/day/woman. The more educated a woman and the older her pregnancy, the higher her VA intake. VA consumption of pregnant women of Northern origin was significantly influenced by their age, whereas for pregnant women of Southern origin, BMI (Body Mass Index) equally had a significant influence on their VA intake. Socio-professional status, marital status and number of children did not significantly influence the daily VA intake of these women. Thus, a pregnant woman originating from the Northern part of the country and having no formal education, consumed less foods rich in carotenoids and therefore was more at risk for vitamin A deficiency.展开更多
Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlatio...Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.展开更多
Many cutting-edge methods are now possible in real-time commercial settings and are growing in popularity on cloud platforms.By incorporating new,cutting-edge technologies to a larger extent without using more infrast...Many cutting-edge methods are now possible in real-time commercial settings and are growing in popularity on cloud platforms.By incorporating new,cutting-edge technologies to a larger extent without using more infrastructures,the information technology platform is anticipating a completely new level of devel-opment.The following concepts are proposed in this research paper:1)A reliable authentication method Data replication that is optimised;graph-based data encryp-tion and packing colouring in Redundant Array of Independent Disks(RAID)sto-rage.At the data centre,data is encrypted using crypto keys called Key Streams.These keys are produced using the packing colouring method in the web graph’s jump graph.In order to achieve space efficiency,the replication is carried out on optimised many servers employing packing colours.It would be thought that more connections would provide better authentication.This study provides an innovative architecture with robust security,enhanced authentication,and low cost.展开更多
Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants ...Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.展开更多
The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation...The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation of historical transformations of state borders of Georgia throughout of XIX-XX centuries and identification the leading geographical factors. Special emphasis has been made on geographical and cartometric analysis of modern state border of Georgia. In order to identify the historical transformations of state border that have used different methods as well as GIS-technologies, the research is based on the historical, cartographical and statistical data. On the base of a lot of cartographic sources, it is concluded that the borderline in modem topographic maps is often plotted by ignoring the international practice related to plotting the state borders across the physical-geographical objects. This is why the geographical factor seems important in the historical transformations of the state border creating similarly a negative perspective in the future. The main results of research are： （1） classification of geographical factors causing the transformations of the state borders; （2） Evaluation of sensitivity of state border; and （3） creation of DB of the state border of Georgia, allowing continuing the studies in the future.展开更多
Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network...Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network. Since traffic flow data has complex spatio-temporal correlation and non-linearity, existing prediction methods are mainly accomplished through a combination of a Graph Convolutional Network (GCN) and a recurrent neural network. The combination strategy has an excellent performance in traffic prediction tasks. However, multi-step prediction error accumulates with the predicted step size. Some scholars use multiple sampling sequences to achieve more accurate prediction results. But it requires high hardware conditions and multiplied training time. Considering the spatiotemporal correlation of traffic flow and influence of external factors, we propose an Attention Based Spatio-Temporal Graph Convolutional Network considering External Factors (ABSTGCN-EF) for multi-step traffic flow prediction. This model models the traffic flow as diffusion on a digraph and extracts the spatial characteristics of traffic flow through GCN. We add meaningful time-slots attention to the encoder-decoder to form an Attention Encoder Network (AEN) to handle temporal correlation. The attention vector is used as a competitive choice to draw the correlation between predicted states and historical states. We considered the impact of three external factors (daytime, weekdays, and traffic accident markers) on the traffic flow prediction tasks. Experiments on two public data sets show that it makes sense to consider external factors. The prediction performance of our ABSTGCN-EF model achieves 7.2%–8.7% higher than the state-of-the-art baselines.展开更多
For forest ecosystem management to be effective, knowledge of the horizontal and vertical structural diversity of a forest is essential. The moist Afromontane highlands of Wondo Genet in south-central Ethiopia present...For forest ecosystem management to be effective, knowledge of the horizontal and vertical structural diversity of a forest is essential. The moist Afromontane highlands of Wondo Genet in south-central Ethiopia present an opportunity to restore and rehabilitate and enhance the ecosystem services to be obtained from this forest sustainably. We focused on the forest structural characteristics to better understand the current forest conditions to assist in the sustainable management of this resource. A total of 75 （20 m × 20 m） quadrats were sampled and diame- ter at breast height （DBH） 〉2 cm and stem height 〉2 m were measured. Species identity and abundance, elevation, slope, and aspect were recorded for each plot. Structural characteristics were computed for each plot. Relationship of topographic factors with vegetation characteristics was conducted using R-Software. A total of 72 woody species was re- corded. Whereas, the overall diameter distribution shows an inverted J-shaped curve, the basal area followed a bell-shaped pattern. Five types of population structures are revealed. The mean tree density and basal area was 397.3 stems.ha-1 and 31.4 m2.ha-1, respectively. Only 2.8% of the tree species have densities of 〉25 stems.ha^-1 and the percentage dis- tribution of trees show 56.2% in the DBH class 2-10 cm, indicating that the forest is dominated by medium-sized trees. Celtis africana （8.81 m2.ha^-1） and Pouteria adolfi-friederieii （5.13 m2.ha^-1） make the highest contribution to the basal area and species importance value index. The families/species with the highest importance value index are Ulmaceae, Fabacea and Sapotaceae. Species abundance （r2 = 0.32, p 〈0.001） and species richness （P =0.50, p 〈0.001） are positively related with tree density. Tree density is negatively related with elevation （~ = -0.36, p 〈0.001）, slope （r2 =-0.15, p 〈0.001） and aspect （r2 = -0.07, p 〈0.05）. While basal area is negatively related with elevation （r2 =-0.14, p 〈0.001）, it has a positive relationship with tree density （r2 =0.28, p 〈0.001 and species richness （r2 =0.098）. Species with poor population structure should be assisted by restoration tasks and further anthropogenic distur- bance such as illegal logging and fuel wood extraction should be re- stricted.展开更多
Rice planting patterns have changed dramatically over the past several decades in northeast China （NEC） due to the combined influence of global change and agricultural policy. Except for its great implications for e...Rice planting patterns have changed dramatically over the past several decades in northeast China （NEC） due to the combined influence of global change and agricultural policy. Except for its great implications for environmental protection and climate change adaption, the spatio-temporal changes of rice cultivation in NEC are not clear. In this study, we conducted spatio-temporal analyses of NEC＇s major rice production region, Heilongjiang Province, by using satellite-derived rice cultivation maps. We found that the total cultivated area of rice in Heilongjiang Province increased largely from 1993 to 2011 and it expanded spatially to the northern and eastern part of the Sanjiang Plain. The results also showed that rice cultivation areas experienced a larger increase in the region managed by the Reclamation Management Bureau （RMB） than that managed by the local provincial government. Rice cultivation changes were closely related with those geographic factors over the investigated periods, represented by the geomorphic （slope）, climatic （accumulated temperature）, and hydrological （watershed） variables. These findings provide clear evidence that crop cultivation in NEC has been modified to better cope with the global change.展开更多
Human factors are critical causes of modern aviation accidents. However, existing accident analysis methods encounter limitations in addressing aviation human factors, especially in complex accident scenarios. The exi...Human factors are critical causes of modern aviation accidents. However, existing accident analysis methods encounter limitations in addressing aviation human factors, especially in complex accident scenarios. The existing graphic approaches are effective for describing accident mechanisms within various categories of human factors, but cannot simultaneously describe inad- equate human-aircraft-environment interactions and organizational deficiencies effectively, and highly depend on analysts＇ skills and experiences. Moreover, the existing methods do not emphasize latent unsafe factors outside accidents. This paper focuses on the above three limitations and proposes an integrated graphi^taxonomic-associative approach. A new graphic model named accident tree （AceiTree）, with a two-mode structure and a reaction-based concept, is developed for accident modeling and safety defense identification. The AcciTree model is then integrated with the well-established human factors analysis and classification system （HFACS） to enhance both reliability of the graphic part and logicality of the taxonomic part for improving completeness of analysis. An associative hazard analysis technique is further put forward to extend analysis to fac- tors outside accidents, to form extended safety requirements for proactive accident prevention. Two crash examples, a research flight demonstrator by our team and an industrial unmanned aircraft, illustrate that the integrated approach is effective for identifying more unsafe factors and safety requirements.展开更多
Currently,functional connectomes constructed from neuroimaging data have emerged as a powerful tool in identifying brain disorders.If one brain disease just manifests as some cognitive dysfunction,it means that the di...Currently,functional connectomes constructed from neuroimaging data have emerged as a powerful tool in identifying brain disorders.If one brain disease just manifests as some cognitive dysfunction,it means that the disease may affect some local connectivity in the brain functional network.That is,there are functional abnormalities in the sub-network.Therefore,it is crucial to accurately identify them in pathological diagnosis.To solve these problems,we proposed a sub-network extraction method based on graph regularization nonnegative matrix factorization(GNMF).The dynamic functional networks of normal subjects and early mild cognitive impairment(eMCI)subjects were vectorized and the functional connection vectors(FCV)were assembled to aggregation matrices.Then GNMF was applied to factorize the aggregation matrix to get the base matrix,in which the column vectors were restored to a common sub-network and a distinctive sub-network,and visualization and statistical analysis were conducted on the two sub-networks,respectively.Experimental results demonstrated that,compared with other matrix factorization methods,the proposed method can more obviously reflect the similarity between the common subnetwork of eMCI subjects and normal subjects,as well as the difference between the distinctive sub-network of eMCI subjects and normal subjects,Therefore,the high-dimensional features in brain functional networks can be best represented locally in the lowdimensional space,which provides a new idea for studying brain functional connectomes.展开更多
Rubber plantation is the major land use type in Southeast Asia. Monitoring the spa- tial-temporal pattern of rubber plantation is significant for regional land resource development, eco-environmental protection, and m...Rubber plantation is the major land use type in Southeast Asia. Monitoring the spa- tial-temporal pattern of rubber plantation is significant for regional land resource development, eco-environmental protection, and maintaining border security. With remote sensing tech- nologies, we analyzed the rubber distribution pattern and spatial-temporal dynamic; with GIS and a newly proposed index of Planted Intensity （PI）, we further quantified the impacts and limits of topographical factors on rubber plantation in the border region of China, Laos and Myanmar （BRCLM） between 1980 and 2010. The results showed that： （1） As the dominant land use type in this border region, the acreage of rubber plantation was 6014 km2 in 2010, accounting for 8.17% of the total area. Viewing from the rubber plantation structure, the ratio of mature- （〉10 year） and young rubber plantation （〈 10 year） was 5：7. （2） From 1980 to 2010, rubber plantation expanded significantly in BRCLM, from 705 km2 to 6014 km2, nearly nine times. The distribution characteristics of rubber plantation varied from concentrated toward dispersed, from border inside to outside, and expanded further in all directions with Jinghong City as the center. （3） Restricted by the topographical factors, more than 4/5 proportion of rubber plantation concentrated in the appropriate elevation gradients between 600 and 1000 m, rarely occurred in elevations beyond 1200 m in BRCLM. Nearly 2/3 of rubber plantation concentrated on slopes of 8^-25~, rarely distributed on slopes above 35~. Rubber plantation was primarily distributed in south and east aspects, relatively few in north and west aspects. Rubber planted intensity displayed the similar distribution trend. （4） Comparative studies of rubber plantation in different countries showed that there was a remarkable increase in area at higher elevations and steeper slopes in China, while there were large appropriate topog- raphical gradients for rubber plantation in Laos and Myanmar which benefited China for rubber trans-boundary expansion. （5） Rubber plantation in BRCLM will definitely expend cross borders of China to the territories of Laos and Myanmar, and the continuous expansion in the border region of China will be inevitable.展开更多
基金supported in part by the National Nature Science Foundation of China(62273239,62103283).
文摘Dear Editor,Pose graph optimization(PGO)is a popular optimization approach that plays a crucial role in the simultaneous localization and mapping(SLAM)back-end.However,when incorrect loop closure constraints(referred to as outliers)are present in the SLAM front-end,the standard PGO algorithm fails catastrophically and can not return an accurate map.To address this issue,this letter proposes a novel algorithm that leverages classical optimization methods to effectively handle outliers.The proposed algorithm introduces a new formulation that incorporates a credibility factor model,which improves the robustness of the optimization process.Additionally,an innovative consistency classification algorithm is developed to detect outliers.Extensive experiments are conducted on multiple benchmark datasets to evaluate the consistency and accuracy of the proposed algorithm.
基金supported by the National Natural Science Foundation of China(Grant Nos.42371315,41901213)the Humanities and Social Sciences General Research Program of the Ministry of Education(Grant No.23YJC790141)。
文摘Cropland abandonment has been a widespread phenomenon in mountainous areas due to the increasing number of natural disasters and the massive migration of rural labor in the process of rapid urbanization.Land transfer is a crucial prerequisite for ensuring food security and fostering rural revitalization.How to promote land transfer in mountainous areas remains a challenging but important task.Nevertheless,there is a dearth of research examining land transfers among farm households that specifically address mountainous regions,and the influence of grassroots governance and geographic location has not been thoroughly elucidated within this particular context.Based on 895household samples collected in Dabie Mountainous Area in China,this study employs binary and ordinal logistic regression models to provide a more comprehensive analysis on land transfers among rural households and the determinants,including the decision to transfer land,the existence of land transfer rents,the channel of land transfer,the duration of the transfer,the pre-transfer cultivation situation,and the level of satisfaction with the land transfer rent.The findings reveal that grassroots governance,geographic location,livelihood capital,and demographic factors significantly influence land transfers among rural households.Specifically,villagers'public participation positively affects land transfer participation(β=0.235,p<0.05),while the operation of village rules and regulations negatively impacts it(β=-0.296,p<0.05).Village cadre satisfaction positively influences both land transfer rent(β=0.274,p<0.05)and rent satisfaction(β=0.303,p<0.05).Improved civil relations in the village correlate with lower land transfer rent(β=-0.511,p<0.05),while a better social atmosphere is associated with higher satisfaction with transfer rent(β=0.575,p<0.01).Households at higher elevations tend to prefer government-mediated land transfers with longer durations.The distances to the township and county centers have contrasting effects on land transfer rent,but their impacts on participation in land transfer,choice of transfer channel,and duration are consistent.The study also found that different types of livelihood capital,as well as the demographic characteristics of households,significantly affect various aspects of land transfer.These empirical findings can inform policymaking to promote more efficient land transfers in mountainous region.
基金funded by the Guangdong Major Project of Basic and Applied Basic Research(2021B0301030007)the Supplemental Funds for Major Scientific Research Projects of Beijing Normal University,Zhuhai(ZHPT2023013)+1 种基金the National Natural Science Foundation of China(42301387)the Science and Technology Program of Guangdong(No.2024B1212070012)。
文摘The topographic factor(LS factor),derived from the multiplication of the slope length(L)and slope steepness(S)factors,is a vital parameter in soil erosion models.Generated from the digital elevation model(DEM),the LS factor always varies with the changing DEM resolution,i.e.,the LS factor scale effect.Previous studies have found the phenomenon of the LS factor scale effect,but the underlying causes of this phenomenon has not been well explored.Therefore,how the DEM resolution affects the LS factor and how the scale effect of the L and S factors influence the LS factor scale effect remains unclear.To address these problems,we collected 20 watersheds from the Guangdong Province with different topographic reliefs,and compared the corresponding L,S and LS factors at 10-m and 30-m resolution DEMs.Our results indicate that the S factor,heavily influenced by slope underestimation in coarse-resolution DEMs,makes a difference in the LS factor scale effect.In addition,the LS factor scale effect becomes less significant with increasing reliefs,suggesting the possibility of using 30-m DEM for LS calculation in rugged terrains.Our findings on the underlying mechanisms of the LS factor scale effect help to identify the uncertainty in the LS factor estimation,thereby enhancing the accuracy of soil erosion assessment,particularly in regions with different topographic characteristics and contribute to more effective soil conservation strategies and decision-making.
基金supported by the Christian Health Association of Ghana under Global Fund New Funding Model 3(NFM 3)HIV/TB Community Systems Strengthening programme(CSS)。
文摘Objective:Intimate partner violence(IPV)among people living with the human immune deficiency virus(PLHIV)poses a significant threat to efforts to reduce the spread of human immune deficiency virus(HIV)and achieve the sustainable development goals.In Ghana,scholarly research on the forms and prevalence of IPV is available,however knowledge of the prevalence of IPV among PLHIV is limited.To understand the prevalence of IPV among PLHIV and the intersectional factors that contribute to it,this study examined the overall prevalence of IPV among PLHIV and the associated sociodemographic factors across ten regions of Ghana.Methods:We administered face-to-face survey questionnaires to 661 randomly selected antiretroviral therapy(ART)clients using Research Electronic Data Capture tools.We used descriptive statistics(mean,standard deviation,minimum,and maximum),pairwise correlation,and multivariate regression analysis to look at the data.Results:The clients of ART experienced various forms of IPV,including sexual,physical,emotional,and economic violence and controlling behaviour.The overall prevalence of IPV among PLHIV was 27.5%.This result,although on par with the global IPV average(27%),is 1.5%higher than the national rate(26%).The Upper West Region had the highest prevalence in all the categories of IPV analysed,followed by Oti Region in second place and the Upper East Region in third,except for the prevalence of sexual violence,where Greater Accra Region ranks second.In specific regions of Ghana,sociodemographic factors shaped by patriarchal and economic considerations contribute to a higher prevalence of IPV among people living with HIV.Conclusion:The findings have implications for developing policies and interventions that address the specific factors associated with HIV-induced IPV in different regions of Ghana.These interventions should also include screening PLHIV receiving ART for their IPV status regardless of gender and deploying culturally appropriate education at the community level to foster empathy towards intimate partners living with HIV.
基金supported by the National Natural Science Foundation of China(Grant No.41174117 and 41474109)the National Key Basic Research Development Program of China(Grant No.2013CB228606)
文摘The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.
基金Major Program of National Social Science Foundation of China,No.21&ZD107。
文摘Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.
文摘This study was to survey the relationship between semen values and demographics,comorbidities,and recreational substance use in a large cohort of adult men at the University of Chicago Medical Center Department of Urology(Chicago,IL,USA).We performed an analysis from January 2013 to December 2023 of semen samples obtained from adult patients at our institution and collected their demographics,comorbid medical conditions,and recreational substance use information.Patients were divided into categories of normozoospermia,oligozoospermia,and azoospermia on the basis of the 5th version of the World Health Organization(WHO)guidelines.Data were analyzed by univariate linear and logistic regression models,after which statistically significant variables were placed into multivariable models.Azoospermia and oligozoospermia were both associated with Caucasian or Black,Indigenous,and People of Color(BIPOC)race(both P<0.001),increasing age(P=0.005 and P<0.001,respectively),anemia(P<0.001 and P=0.02,respectively),lifetime tobacco use(both P<0.001),lifetime alcohol use(P=0.02 and P<0.001,respectively),and lifetime use of at least two recreational substances(P<0.001 and P=0.003,respectively)in multivariable models.Oligospermia was additionally associated with benign prostatic hyperplasia(BPH;P=0.003)in multivariable models.This study suggests that at-risk populations may benefit from additional early screening and workup for infertility.
基金funded by the National Natural Science Foundation of China(Grant No.41871294)
文摘Terrain can influence the spatial distribution of settlements. Studies on the terrain characteristics of settlements can help to understand the effects of the environment on human activities. This paper provides a quantitative analysis of the relationship between settlements and topographical factors. A statistically significant sample of residential locations and ASTER GDEM V2 were used to investigate terrain traits and settlements distributions. We selected eight topographical factors and introduced a practical concept, distributive entropy, into assessing the aggregation extent of the settlements' spatial distribution. The study showed that topography varies within the study area, and distributive entropy indicates that settlements have distinctive distribution tendency in statistic approach. According to the results of this study, mountain inhabitants prefer to settle in valleys. Additionally, with distributive entropy, residential suitability was divided to three levels: suitable, normal, and unsuited. The results showed that suitable area is small in Sichuan Province, accounting for 8.2%～29.9%; however, unsuited area is large, accounting for 33%～63.3%.
基金the National "11th Five Year" Plan of Science and technology (2006BAD26B06,2006BAD03A1205) Ecological Restore Project of Water Resources Ministry of China (2006-2008)
文摘The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.
文摘Variability in vitamin A (VA) intake of pregnant women in Ngaoundere town according to geographic origin, socio-professional and demographic factors was studied. A total of 100 pregnant women attending ante natal visits at the Regional Hospital in Ngaoundere were involved in the survey. A questionnaire was used to obtain information on geographic origin, socio-professional status, birth history, demographic and anthropometric factors. Dietary intake was assessed using 24-hour dietary recall. Meals potentially rich in VA consumed by these women were collected, their carotenoids contents quantified and VA activity determined by conversion. Results indicated that daily VA intake of these women varied significantly (p < 0.05) with geographic origin, level of education and age of pregnancy. VA intake of pregnant women of Northern origin (Adamawa, North and Far North Regions) was significantly (p < 0.05) lower (496 μg/day/woman) than that of women of Southern origin (588 μg/day/woman), although both were below the recommended intake of 800 μg/day/woman. The more educated a woman and the older her pregnancy, the higher her VA intake. VA consumption of pregnant women of Northern origin was significantly influenced by their age, whereas for pregnant women of Southern origin, BMI (Body Mass Index) equally had a significant influence on their VA intake. Socio-professional status, marital status and number of children did not significantly influence the daily VA intake of these women. Thus, a pregnant woman originating from the Northern part of the country and having no formal education, consumed less foods rich in carotenoids and therefore was more at risk for vitamin A deficiency.
基金This work was supported by the National Basic Research Program of China (2003CB415002) and the China Postdoctoral Science Foundation (No. 2003033486) and the Natural Science Research Fund of University in Jiangsu (04KJB150149)
文摘Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.
文摘Many cutting-edge methods are now possible in real-time commercial settings and are growing in popularity on cloud platforms.By incorporating new,cutting-edge technologies to a larger extent without using more infrastructures,the information technology platform is anticipating a completely new level of devel-opment.The following concepts are proposed in this research paper:1)A reliable authentication method Data replication that is optimised;graph-based data encryp-tion and packing colouring in Redundant Array of Independent Disks(RAID)sto-rage.At the data centre,data is encrypted using crypto keys called Key Streams.These keys are produced using the packing colouring method in the web graph’s jump graph.In order to achieve space efficiency,the replication is carried out on optimised many servers employing packing colours.It would be thought that more connections would provide better authentication.This study provides an innovative architecture with robust security,enhanced authentication,and low cost.
基金Ecological Restoration Cost Evaluation in Archipelago Ecosystems:A Case Study in Putuo,Zhoushan Archipelago,East China Sea.
文摘Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.
文摘The work deals with analysis of geographical factor as one of the main factor determining the historical change of a border on the example of Georgia. The research was conducted in two main directions： the evaluation of historical transformations of state borders of Georgia throughout of XIX-XX centuries and identification the leading geographical factors. Special emphasis has been made on geographical and cartometric analysis of modern state border of Georgia. In order to identify the historical transformations of state border that have used different methods as well as GIS-technologies, the research is based on the historical, cartographical and statistical data. On the base of a lot of cartographic sources, it is concluded that the borderline in modem topographic maps is often plotted by ignoring the international practice related to plotting the state borders across the physical-geographical objects. This is why the geographical factor seems important in the historical transformations of the state border creating similarly a negative perspective in the future. The main results of research are： （1） classification of geographical factors causing the transformations of the state borders; （2） Evaluation of sensitivity of state border; and （3） creation of DB of the state border of Georgia, allowing continuing the studies in the future.
基金supported by the Nation Natural Science Foundation of China(NSFC)under Grant No.61462042 and No.61966018.
文摘Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network. Since traffic flow data has complex spatio-temporal correlation and non-linearity, existing prediction methods are mainly accomplished through a combination of a Graph Convolutional Network (GCN) and a recurrent neural network. The combination strategy has an excellent performance in traffic prediction tasks. However, multi-step prediction error accumulates with the predicted step size. Some scholars use multiple sampling sequences to achieve more accurate prediction results. But it requires high hardware conditions and multiplied training time. Considering the spatiotemporal correlation of traffic flow and influence of external factors, we propose an Attention Based Spatio-Temporal Graph Convolutional Network considering External Factors (ABSTGCN-EF) for multi-step traffic flow prediction. This model models the traffic flow as diffusion on a digraph and extracts the spatial characteristics of traffic flow through GCN. We add meaningful time-slots attention to the encoder-decoder to form an Attention Encoder Network (AEN) to handle temporal correlation. The attention vector is used as a competitive choice to draw the correlation between predicted states and historical states. We considered the impact of three external factors (daytime, weekdays, and traffic accident markers) on the traffic flow prediction tasks. Experiments on two public data sets show that it makes sense to consider external factors. The prediction performance of our ABSTGCN-EF model achieves 7.2%–8.7% higher than the state-of-the-art baselines.
基金spported by the Swedish International Development Agency (SIDA)Center for International Mobility (CIMO,Finland)+1 种基金International Foundation for Science (IFS Grt. No.D/5053-1)for the first author’s financial support
文摘For forest ecosystem management to be effective, knowledge of the horizontal and vertical structural diversity of a forest is essential. The moist Afromontane highlands of Wondo Genet in south-central Ethiopia present an opportunity to restore and rehabilitate and enhance the ecosystem services to be obtained from this forest sustainably. We focused on the forest structural characteristics to better understand the current forest conditions to assist in the sustainable management of this resource. A total of 75 （20 m × 20 m） quadrats were sampled and diame- ter at breast height （DBH） 〉2 cm and stem height 〉2 m were measured. Species identity and abundance, elevation, slope, and aspect were recorded for each plot. Structural characteristics were computed for each plot. Relationship of topographic factors with vegetation characteristics was conducted using R-Software. A total of 72 woody species was re- corded. Whereas, the overall diameter distribution shows an inverted J-shaped curve, the basal area followed a bell-shaped pattern. Five types of population structures are revealed. The mean tree density and basal area was 397.3 stems.ha-1 and 31.4 m2.ha-1, respectively. Only 2.8% of the tree species have densities of 〉25 stems.ha^-1 and the percentage dis- tribution of trees show 56.2% in the DBH class 2-10 cm, indicating that the forest is dominated by medium-sized trees. Celtis africana （8.81 m2.ha^-1） and Pouteria adolfi-friederieii （5.13 m2.ha^-1） make the highest contribution to the basal area and species importance value index. The families/species with the highest importance value index are Ulmaceae, Fabacea and Sapotaceae. Species abundance （r2 = 0.32, p 〈0.001） and species richness （P =0.50, p 〈0.001） are positively related with tree density. Tree density is negatively related with elevation （~ = -0.36, p 〈0.001）, slope （r2 =-0.15, p 〈0.001） and aspect （r2 = -0.07, p 〈0.05）. While basal area is negatively related with elevation （r2 =-0.14, p 〈0.001）, it has a positive relationship with tree density （r2 =0.28, p 〈0.001 and species richness （r2 =0.098）. Species with poor population structure should be assisted by restoration tasks and further anthropogenic distur- bance such as illegal logging and fuel wood extraction should be re- stricted.
基金financially supported by the Opening Foundation of the Key Laboratory of Agricultural Information Technology,Ministry of Agriculture,China (2016009)the National Natural Science Foundation of China (41501111 and 41271112)
文摘Rice planting patterns have changed dramatically over the past several decades in northeast China （NEC） due to the combined influence of global change and agricultural policy. Except for its great implications for environmental protection and climate change adaption, the spatio-temporal changes of rice cultivation in NEC are not clear. In this study, we conducted spatio-temporal analyses of NEC＇s major rice production region, Heilongjiang Province, by using satellite-derived rice cultivation maps. We found that the total cultivated area of rice in Heilongjiang Province increased largely from 1993 to 2011 and it expanded spatially to the northern and eastern part of the Sanjiang Plain. The results also showed that rice cultivation areas experienced a larger increase in the region managed by the Reclamation Management Bureau （RMB） than that managed by the local provincial government. Rice cultivation changes were closely related with those geographic factors over the investigated periods, represented by the geomorphic （slope）, climatic （accumulated temperature）, and hydrological （watershed） variables. These findings provide clear evidence that crop cultivation in NEC has been modified to better cope with the global change.
基金co-supported by the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (IRT0905)the Step Program of Beijing Key Laboratory (No. Z121104002812053)
文摘Human factors are critical causes of modern aviation accidents. However, existing accident analysis methods encounter limitations in addressing aviation human factors, especially in complex accident scenarios. The existing graphic approaches are effective for describing accident mechanisms within various categories of human factors, but cannot simultaneously describe inad- equate human-aircraft-environment interactions and organizational deficiencies effectively, and highly depend on analysts＇ skills and experiences. Moreover, the existing methods do not emphasize latent unsafe factors outside accidents. This paper focuses on the above three limitations and proposes an integrated graphi^taxonomic-associative approach. A new graphic model named accident tree （AceiTree）, with a two-mode structure and a reaction-based concept, is developed for accident modeling and safety defense identification. The AcciTree model is then integrated with the well-established human factors analysis and classification system （HFACS） to enhance both reliability of the graphic part and logicality of the taxonomic part for improving completeness of analysis. An associative hazard analysis technique is further put forward to extend analysis to fac- tors outside accidents, to form extended safety requirements for proactive accident prevention. Two crash examples, a research flight demonstrator by our team and an industrial unmanned aircraft, illustrate that the integrated approach is effective for identifying more unsafe factors and safety requirements.
基金supported by the National Natural Science Foundation of China(No.51877013),(ZJ),(http://www.nsfc.gov.cn/)the Natural Science Foundation of Jiangsu Province(No.BK20181463),(ZJ),(http://kxjst.jiangsu.gov.cn/)sponsored by Qing Lan Project of Jiangsu Province(no specific grant number),(ZJ),(http://jyt.jiangsu.gov.cn/).
文摘Currently,functional connectomes constructed from neuroimaging data have emerged as a powerful tool in identifying brain disorders.If one brain disease just manifests as some cognitive dysfunction,it means that the disease may affect some local connectivity in the brain functional network.That is,there are functional abnormalities in the sub-network.Therefore,it is crucial to accurately identify them in pathological diagnosis.To solve these problems,we proposed a sub-network extraction method based on graph regularization nonnegative matrix factorization(GNMF).The dynamic functional networks of normal subjects and early mild cognitive impairment(eMCI)subjects were vectorized and the functional connection vectors(FCV)were assembled to aggregation matrices.Then GNMF was applied to factorize the aggregation matrix to get the base matrix,in which the column vectors were restored to a common sub-network and a distinctive sub-network,and visualization and statistical analysis were conducted on the two sub-networks,respectively.Experimental results demonstrated that,compared with other matrix factorization methods,the proposed method can more obviously reflect the similarity between the common subnetwork of eMCI subjects and normal subjects,as well as the difference between the distinctive sub-network of eMCI subjects and normal subjects,Therefore,the high-dimensional features in brain functional networks can be best represented locally in the lowdimensional space,which provides a new idea for studying brain functional connectomes.
基金National Natural Science Foundation of China, No.41271117 Strategy of Science and Technology Planning Project of Institute of Geographic Sciences and Natural Resources Research, CAS, No.2012SJ008
文摘Rubber plantation is the major land use type in Southeast Asia. Monitoring the spa- tial-temporal pattern of rubber plantation is significant for regional land resource development, eco-environmental protection, and maintaining border security. With remote sensing tech- nologies, we analyzed the rubber distribution pattern and spatial-temporal dynamic; with GIS and a newly proposed index of Planted Intensity （PI）, we further quantified the impacts and limits of topographical factors on rubber plantation in the border region of China, Laos and Myanmar （BRCLM） between 1980 and 2010. The results showed that： （1） As the dominant land use type in this border region, the acreage of rubber plantation was 6014 km2 in 2010, accounting for 8.17% of the total area. Viewing from the rubber plantation structure, the ratio of mature- （〉10 year） and young rubber plantation （〈 10 year） was 5：7. （2） From 1980 to 2010, rubber plantation expanded significantly in BRCLM, from 705 km2 to 6014 km2, nearly nine times. The distribution characteristics of rubber plantation varied from concentrated toward dispersed, from border inside to outside, and expanded further in all directions with Jinghong City as the center. （3） Restricted by the topographical factors, more than 4/5 proportion of rubber plantation concentrated in the appropriate elevation gradients between 600 and 1000 m, rarely occurred in elevations beyond 1200 m in BRCLM. Nearly 2/3 of rubber plantation concentrated on slopes of 8^-25~, rarely distributed on slopes above 35~. Rubber plantation was primarily distributed in south and east aspects, relatively few in north and west aspects. Rubber planted intensity displayed the similar distribution trend. （4） Comparative studies of rubber plantation in different countries showed that there was a remarkable increase in area at higher elevations and steeper slopes in China, while there were large appropriate topog- raphical gradients for rubber plantation in Laos and Myanmar which benefited China for rubber trans-boundary expansion. （5） Rubber plantation in BRCLM will definitely expend cross borders of China to the territories of Laos and Myanmar, and the continuous expansion in the border region of China will be inevitable.
