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Distributed event region fault-tolerance based on weighted distance for wireless sensor networks 被引量:2
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作者 Li Ping Li Hong Wu Min 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第6期1351-1360,共10页
Event region detection is the important application for wireless sensor networks(WSNs), where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment n... Event region detection is the important application for wireless sensor networks(WSNs), where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment nodes fault-tolerance, a novel distributed fault-tolerant detection algorithm named distributed fault-tolerance based on weighted distance(DFWD) is proposed, which exploits the spatial correlation among sensor nodes and their redundant information.In sensor networks, neighborhood sensor nodes will be endowed with different relative weights respectively according to the distances between them and the central node.Having syncretized the weighted information of dual-neighborhood nodes appropriately, it is reasonable to decide the ultimate status of the central sensor node.Simultaneously, readings of faulty sensors would be corrected during this process.Simulation results demonstrate that the DFWD has a higher fault detection accuracy compared with other algorithms, and when the sensor fault probability is 10%, the DFWD can still correct more than 91% faulty sensor nodes, which significantly improves the performance of the whole sensor network. 展开更多
关键词 event region detection weighted distance distributed fault-tolerance wireless sensor network.
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ORDERED WEIGHTED DISTANCE MEASURE 被引量:16
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作者 Zeshui XU Jian CHEN 《Journal of Systems Science and Systems Engineering》 SCIE EI CSCD 2008年第4期432-445,共14页
The aim of this paper is to develop an ordered weighted distance (OWD) measure, which is the generalization of some widely used distance measures, including the normalized Hamming distance, the normalized Euclidean ... The aim of this paper is to develop an ordered weighted distance (OWD) measure, which is the generalization of some widely used distance measures, including the normalized Hamming distance, the normalized Euclidean distance, the normalized geometric distance, the max distance, the median distance and the rain distance, etc. Moreover, the ordered weighted averaging operator, the generalized ordered weighted aggregation operator, the ordered weighted geometric operator, the averaging operator, the geometric mean operator, the ordered weighted square root operator, the square root operator, the max operator, the median operator and the rain operator are also the special cases of the OWD measure. Some methods depending on the input arguments are given to determine the weights associated with the OWD measure. The prominent characteristic of the OWD measure is that it can relieve (or intensify) the influence of unduly large or unduly small deviations on the aggregation results by assigning them low (or high) weights. This desirable characteristic makes the OWD measure very suitable to be used in many actual fields, including group decision making, medical diagnosis, data mining, and pattern recognition, etc. Finally, based on the OWD measure, we develop a group decision making approach, and illustrate it with a numerical example. 展开更多
关键词 Group decision making ordered weighted distance (OWD) measure aggregation operator
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Prediction-Based Distance Weighted Algorithm for Target Tracking in Binary Sensor Network
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作者 SUN Xiaoyan LI Jiandong +1 位作者 CHEN Yanhui HUANG Pengyu 《China Communications》 SCIE CSCD 2010年第4期41-50,共10页
Binary sensor network(BSN) are becoming more attractive due to the low cost deployment,small size,low energy consumption and simple operation.There are two different ways for target tracking in BSN,the weighted algori... Binary sensor network(BSN) are becoming more attractive due to the low cost deployment,small size,low energy consumption and simple operation.There are two different ways for target tracking in BSN,the weighted algorithms and particle filtering algorithm.The weighted algorithms have good realtime property,however have poor estimation property and some of them does not suit for target’s variable velocity model.The particle filtering algorithm can estimate target's position more accurately with poor realtime property and is not suitable for target’s constant velocity model.In this paper distance weight is adopted to estimate the target’s position,which is different from the existing distance weight in other papers.On the analysis of principle of distance weight (DW),prediction-based distance weighted(PDW) algorithm for target tracking in BSN is proposed.Simulation results proved PDW fits for target's constant and variable velocity models with accurate estimation and good realtime property. 展开更多
关键词 Binary Sensor Network weighted Algorithm Particle Filter distance Weight Recursive Least Squre(RLS)
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Mapping Distribution of Precipitation, Temperature and Evaporation in Seydisuyu Basin with the Help of Distance Related Estimation Methods
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作者 Yildirim Bayazit Recep Bakiş Cengiz Koç 《Journal of Geographic Information System》 2016年第2期224-237,共14页
In this research, distributions of precipitation, temperature and evaporation in Seydisuyu basin were analyzed with the help of inverse distance weighted (IDW) method. Because real meteorological data of the basin (pr... In this research, distributions of precipitation, temperature and evaporation in Seydisuyu basin were analyzed with the help of inverse distance weighted (IDW) method. Because real meteorological data of the basin (precipitation, temperature and evaporation) do not have normal distribution, precipitation, temperature and evaporation distribution maps are drawn after normalization process. The number of meteorological stations, in other words the number of samples, is low, so only IDW method is used in this research. In addition to the research, reliability of the results obtained with the help of inverse distance weighting method was examined with accuracy analysis. The purpose of this study, the spatial distribution of meteorological data on a basin or areas is to demonstrate the applicability of the statistical basis. 展开更多
关键词 Inverse distance weighted (IDW) Geographic Information Systems (GIS) METEOROLOGY Seydisuyu-Basin
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Water Quality Evaluation of Chapurson Valley in Hunza Nagar, Gilgit Baltistan, Pakistan, Based on Statistical Analysis and Water Quality Index
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作者 Syeda Urooj Fatima Moazzam Ali Khan +4 位作者 Aamir Alamgir Nasir Sulman Tariq Masood Ali Khan Faisal Ahmed Khan Muhammad Azhar Khan 《Health》 CAS 2023年第5期379-396,共18页
Water borne ailments are of serious public health concern in Gilgit Baltistan’s (GB) region of Pakistan. The pollution load on the glacio-fluvial streams and surface water resources of the Chapurson Valley in the Hun... Water borne ailments are of serious public health concern in Gilgit Baltistan’s (GB) region of Pakistan. The pollution load on the glacio-fluvial streams and surface water resources of the Chapurson Valley in the Hunza Nagar area of the GB is increasing as a result of anthropogenic activities and tourism. The present study focuses on the public health quality of drinking water of Chapurson valley. The study addressed the fundamental drinking water quality criteria in order to understand the state of the public health in the valley. To ascertain the current status of physico-chemical, metals, and bacteriological parameters, 25 water samples were collected through deterministic sampling strategy and examined accordingly. The physico-chemical parameters of the water samples collected from the valley were found to meet the World Health Organization (WHO) guidelines of drinking water. The water samples showed a pattern of mean metal concentrations in order of Arsenic (As) > Lead (Pb) > Iron (Fe) > Zinc (Zn) > Copper (Cu) > Magnesium (Mg) > Calcium (Ca). As, Cu, Zn, Ca and Mg concentration were under the WHO guidelines range. However, results showed that Pb and Fe are present at much higher concentrations than recommended WHO guidelines. Similarly, the results of the bacteriological analysis indicate that the water samples are heavily contaminated with the organisms of public health importance (including total coliforms (TCC), total faecal coliforms (TFC) and total fecal streptococci (TFS) are more than 3 MPN/100mL). Three principal components, accounting for 48.44% of the total variance, were revealed using principal component analysis (PCA). Bacteriological parameters were shown to be the main determinants of the water quality as depicted by the PCA analysis. The dendrogram of Cluster analysis using the Ward’s method validated the same traits of the sampling locations that were found to be contaminated during geospatial analysis using the Inverse Distance Weight (IDW) method. Based on these findings, it is most likely that those anthropogenic activities and essentially the tourism results in pollution load from upstream channels. Metals may be released into surface and groundwater from a few underlying sources as a result of weathering and erosion. This study suggests that the valley water resources are more susceptible to bacteriological contamination and as such no water treatment facilities or protective measure have been taken to encounter the pollution load. People are drinking the contaminated water without questioning about the quality. It is recommended that the water resources of the valley should be monitored using standard protocol so as to protect not only the public health but to safe guard sustainable tourism in the valley. 展开更多
关键词 Chapurson Valley Water Quality PHYSICO-CHEMICAL Principal Component Analysis (PCA) Inverse distance Weight (IDW)
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Using WGM2012 to Compute Gravity Anomaly Corrections of Leveling Observations in China
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作者 Yanhui CAI Li ZHANG Xu MA 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第1期88-94,共7页
Gravity Anomaly Correction(GAC)is a very important term in leveling data processing.In most cases,it is troublesome for field surveyors to measure gravity when leveling.In this paper,based on the complete Bouguer Grav... Gravity Anomaly Correction(GAC)is a very important term in leveling data processing.In most cases,it is troublesome for field surveyors to measure gravity when leveling.In this paper,based on the complete Bouguer Gravity Anomaly(BGA)map of WGM2012,the feasibility of replacing in-situ gravity surveying in China is investigated.For leveling application,that is to evaluate the accuracy of WGM2012 in China.Because WGM2012 is organized with a standard rectangle grid,two interpolation methods,bilinear interpolating and Inverse Distance Weighted(IDW)interpolating,are proposed.Four sample areas in China,i.e.,Hanzhong,Chengdu,Linzhi and Shantou,are selected to evaluate the systems bias and precision of WGM2012.Numerical results show the average system bias of WGM2012 BGA in west China is about-100.1 mGal(1 mGal=10^(-5) m/s^(2))and the standard deviation is about 30.7 mGal.Tests in Shantou indicate the system bias in plain areas is about-130.4 mGal and standard deviation is about 6.8 mGal.All these experiments means the accuracy of WGM2012 is limited in high mountain areas of western China,but in plain areas,such as Shantou,WGM2012 BGA map is quite good for most leveling applications after calibrating the system bias. 展开更多
关键词 Bouguer Gravity Anomaly(BGA) Gravity Anomaly Correction(GAC) precise leveling WGM2012 bilinear Interpolation Inverse distance weighted(IDW)interpolation
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GIS Mapping, Biomonitoring and Distribution of Heavy Metal Concentrations Using Neem (Azadirachta indica) Bark in Makurdi Town, Benue State, Nigeria
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作者 Ada Florence Ogli Mohammed Ahmed +2 位作者 Adams Udoji Itodo Raymond Ahulle Wuana Rufus Sha’Ato 《Journal of Geoscience and Environment Protection》 2023年第7期213-226,共14页
The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific obje... The present work determined the concentration and spatial distribution of heavy metals (As, Hg, Cr, Cd and Pb) in soil samples from Makurdi and its environs using geographic information system (GIS). The specific objective is to produce the spatial distribution maps showing the spatial distribution of toxic heavy metals in the study area. Inverse Distance Weighting (IDW), a GIS technique was used to produce dotted maps showing the spatial distribution of heavy metals in neem bark for better visualization of contamination zones and non-contamination zones. The map reveals few hotspot areas showing areas of high concentrations of the heavy metals investigated which were identified in red colours, the following concentration ranges were obtained;As (4.71 - 6.43 mg/kg), Cd (13.9 - 16.84 mg/kg), Cr (46.3 - 60.84 mg/kg), Hg (3.70 - 5.05 mg/kg) and Pb (24.02 - 31.34 mg/kg). These hotspot areas were found close to business outlets, fuel filling and service stations, farm sites where the application of fertilizers and pesticides were persistent coupled with heavy traffic of vehicles and other machinery which was associated with As, Hg, Cd, Pb and Cr been released into the environment thus, suggesting anthropogenic activities controlling the concentration of these heavy metals in the study areas. The cumulative effect of these heavy metals into the barks of neem could pose as danger, because this plant is used as herbs in folk medicine. 展开更多
关键词 Heavy Metal Contamination Spatial Distribution Inverse distance Weighting Folk Medicine Makurdi
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Identification and spatial patterns of coastal water pollution sources based on GIS and chemometric approach 被引量:3
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作者 ZHOU Feng GUO Huai-cheng LIU Yong HAO Ze-jia 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期805-810,共6页
Comprehensive and joint applications of GIS and chemometric approach were applied in identification and spatial patterns of coastal water pollution sources with a large data set (5 years (2000-2004), 17 parameters... Comprehensive and joint applications of GIS and chemometric approach were applied in identification and spatial patterns of coastal water pollution sources with a large data set (5 years (2000-2004), 17 parameters) obtained through coastal water monitoring of Southern Water Control Zone in Hong Kong. According to cluster analysis the pollution degree was significantly different between September-next May (the 1st period) and June-August (the 2nd period). Based on these results, four potential pollution sources, such as organic/eutrophication pollution, natural pollution, mineral/anthropic pollution and fecal pollution were identified by factor analysis/principal component analysis. Then the factor scores of each monitoring site were analyzed using inverse distance weighting method, and the results indicated degree of the influence by various potential pollution sources differed among the monitoring sites. This study indicated that hybrid approach was useful and effective for identification of coastal water pollution source and spatial patterns. 展开更多
关键词 source identification spatial pattern cluster analysis (CA) principal component analysis (PCA) inverse distance weighting (IDW) Hong Kong
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Phishing Detection with Image Retrieval Based on Improved Texton Correlation Descriptor 被引量:2
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作者 Guoyuan Lin Bowen Liu +2 位作者 Pengcheng Xiao Min Lei Wei Bi 《Computers, Materials & Continua》 SCIE EI 2018年第12期533-547,共15页
Anti-detection is becoming as an emerging challenge for anti-phishing.This paper solves the threats of anti-detection from the threshold setting condition.Enough webpages are considered to complicate threshold setting... Anti-detection is becoming as an emerging challenge for anti-phishing.This paper solves the threats of anti-detection from the threshold setting condition.Enough webpages are considered to complicate threshold setting condition when the threshold is settled.According to the common visual behavior which is easily attracted by the salient region of webpages,image retrieval methods based on texton correlation descriptor(TCD)are improved to obtain enough webpages which have similarity in the salient region for the images of webpages.There are two steps for improving TCD which has advantage of recognizing the salient region of images:(1)This paper proposed Weighted Euclidean Distance based on neighborhood location(NLW-Euclidean distance)and double cross windows,and combine them to solve the problems in TCD;(2)Space structure is introduced to map the image set to Euclid space so that similarity relation among images can be used to complicate threshold setting conditions.Experimental results show that the proposed method can improve the effectiveness of anti-phishing and make the system more stable,and significantly reduce the possibilities of being hacked to be used as mining systems for blockchain. 展开更多
关键词 ANTI-PHISHING blockchain texton correlation descriptor weighted euclidean distance image retrieval
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Large-scale deformation monitoring in mining area by D-InSAR and 3D laser scanning technology integration 被引量:13
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作者 Chen Bingqian Deng Kazhong +1 位作者 Fan Hongdong Hao Ming 《International Journal of Mining Science and Technology》 SCIE EI 2013年第4期545-551,共7页
Large-scale deformation can not be detected by traditional D-InSAR technique because of the limit of its detectable deformation gradient,we propose a method that combines SAR data with point cloud data obtained by 3D ... Large-scale deformation can not be detected by traditional D-InSAR technique because of the limit of its detectable deformation gradient,we propose a method that combines SAR data with point cloud data obtained by 3D laser scanning to improve the gradient of deformation detection.The proposed method takes advantage of high-density of 3D laser scanning point cloud data and its high precision of point positioning after 3D modeling.The specifc process can be described as follows:frst,large-scale deformation points in the interferogram are masked out based on interferometric coherence;second,the interferogram with holes is unwrapped to obtain a deformation map with holes,and last,the holes in the deformation map are flled with point cloud data using inverse distance weighting algorithm,which will achieve seamless connection of monitoring region.We took the embankment dam above working face of a certain mining area in Shandong province as an example to study large-scale deformation in mining area using the proposed method.The results show that the maximum absolute error is 64 mm,relative error of maximum subsidence value is 4.95%,and they are consistent with leveling data of ground observation stations,which confrms the feasibility of this method.The method we presented provides new ways and means for achieving large-scale deformation monitoring by D-InSAR in mining area. 展开更多
关键词 D-InSAR 3D laser scanning Inverse distance weighting Subsidence monitoring TerraSAR-X
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Identifying G-protein Coupled Receptors Using Weighted Levenshtein Distance and Nearest Neighbor Method 被引量:1
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作者 Jian-Hua Xu 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2005年第4期252-257,共6页
G-protein coupled receptors (GPCRs) are a class of seven-helix transmembrane proteins that have been used in bioinformatics as the targets to facilitate drug discovery for human diseases. Although thousands of GPCR ... G-protein coupled receptors (GPCRs) are a class of seven-helix transmembrane proteins that have been used in bioinformatics as the targets to facilitate drug discovery for human diseases. Although thousands of GPCR sequences have been collected, the ligand specificity of many GPCRs is still unknown and only one crystal structure of the rhodopsin-like family has been solved. Therefore, identifying GPCR types only from sequence data has become an important research issue. In this study, a novel technique for identifying GPCR types based on the weighted Levenshtein distance between two receptor sequences and the nearest neighbor method (NNM) is introduced, which can deal with receptor sequences with different lengths directly. In our experiments for classifying four classes (acetylcholine, adrenoceptor, dopamine, and serotonin) of the rhodopsin-like family of GPCRs, the error rates from the leave-one-out procedure and the leave-half-out procedure were 0.62% and 1.24%, respectively. These results are prior to those of the covariant discriminant algorithm, the support vector machine method, and the NNM with Euclidean distance. 展开更多
关键词 GPCR weighted Levenshtein distance nearest neighbor method
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Industrial Green Spatial Pattern Evolution of Yangtze River Economic Belt in China 被引量:3
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作者 LI Lin LIU Ying 《Chinese Geographical Science》 SCIE CSCD 2017年第4期660-672,共13页
We use the directional slacks-based measure of efficiency and inverse distance weighting method to analyze the spatial pattern evolution of the industrial green total factor productivity of 108 cities in the Yangtze R... We use the directional slacks-based measure of efficiency and inverse distance weighting method to analyze the spatial pattern evolution of the industrial green total factor productivity of 108 cities in the Yangtze River Economic Belt in 2003–2013.Results show that both the subprime mortgage crisis and ‘the new normal' had significant negative effects on productivity growth,leading to the different spatial patterns between 2003–2008 and 2009–2013.Before 2008,green poles had gathered around some capital cities and formed a tripartite pattern,which was a typical core-periphery pattern.Due to a combination of the polarization and the diffusion effects,capital cities became the growth poles and ‘core' regions,while surrounding areas became the ‘periphery'.This was mainly caused by the innate advantage of capital cities and ‘the rise of central China' strategy.After 2008,the tripartite pattern changed to a multi-poles pattern where green poles continuously and densely spread in the midstream and downstream areas.This is due to the regional difference in the leading effect of green poles.The leading effect of green poles in midstream and downstream areas has changed from polarization to diffusion,while the polarization effect still leads in the upstream area. 展开更多
关键词 Yangtze River Economic Belt industrial green total factor productivity directional slacks-based measure of efficiency inverse distance weighting spatial pattern evolution
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Correcting Non-Word Errors Using a Combined Method
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作者 曹元大 周杰龙 《Journal of Beijing Institute of Technology》 EI CAS 2005年第3期250-254,共5页
The weighted edit distance and metaphone+ algorithm are combined to correct the non-word errors. The speed is also optimized based on the observation that people rarely make mistakes in the initial letter of a word. ... The weighted edit distance and metaphone+ algorithm are combined to correct the non-word errors. The speed is also optimized based on the observation that people rarely make mistakes in the initial letter of a word. A spelling checker is designed for an automatic detection and correction system for student essays. To evaluate the algorithm it is compared to some famous systems (MS Word2000, Aspell, winEdt). The resuits show that our approach is superior to the alternative approaches. 展开更多
关键词 weighted edit distance metaphone+ initial letter unchanged spelling checker
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A Log-Index Weighted Cepstral Distance Measure for Speech Recognition
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作者 郑方 吴文虎 方棣棠 《Journal of Computer Science & Technology》 SCIE EI CSCD 1997年第2期177-184,共8页
A log-index weighted cepstral distance measure is proposed and tested in speaker-independent and speaker-dependent isolated word recognition systems using statistic techniques. The weights for the cepstral coefficient... A log-index weighted cepstral distance measure is proposed and tested in speaker-independent and speaker-dependent isolated word recognition systems using statistic techniques. The weights for the cepstral coefficients of this measure equal the logarithm of the corresponding indices. The experimental results show that this kind of measure works better than any other weighted Euclidean cepstral distance measures on three speech databases. The error rate obtained using this measure is about 1.8 percent for three databases on average, which is a 25% reduction from that obtained using other measures, and a 40% reduction from that obtained using Log Likelihood Ratio (LLR) measure. The experimental results also show that this kind of distance measure works well in both speaker-dependent and speaker-independent speech recognition systems. 展开更多
关键词 Log-index weighted cepstral distance measure speech recognition
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Analysis on Change Characteristics of PCD and PCP in Beijiang River Basin
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作者 Liu Zhanming 《Meteorological and Environmental Research》 CAS 2018年第6期1-4,共4页
Based on the daily precipitation data between 1965 and 2009 from 18 rainfall stations in Guangdong Beijiang River basin and the definitions of Precipitation Concentration Degree(PCD) and Precipitation Concentration Pe... Based on the daily precipitation data between 1965 and 2009 from 18 rainfall stations in Guangdong Beijiang River basin and the definitions of Precipitation Concentration Degree(PCD) and Precipitation Concentration Period(PCP),the inhomogeneous distribution characteristics of interannual precipitation were analyzed by introducing the spatial distribution of annual mean values,variable coefficients,correlation coefficients between annual precipitation,change trends and composite analysis. The results showed that(1) PCD mainly decreased from south to north in spatial distribution; PCP was earlier in most of north-central basin,but relatively later in southern basin.(2) Annual precipitation would increase if PCD decreased in most of river basin,and annual precipitation would decrease as PCP lagged in southern basin,but the change trend was the opposite in northern basin.(3) PCD and PCP mainly showed insignificant upward trend in the entire basin by Mann-Kendall test. 展开更多
关键词 Precipitation concentration degree Precipitation concentration period Beijiang River basin Inverse distance weighted interpolation
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Analysis of Intra-annual Heterogeneous Characteristics of Precipitation in Shaoguan City
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作者 Liu Zhanming 《Meteorological and Environmental Research》 CAS 2018年第1期15-19,共5页
Based on the daily precipitation data between 1965 and 2009 from 8 rainfall stations in Shaoguan City,the indexes of precipitation concentration degree( PCD) and precipitation concentration period( PCP) were calcu... Based on the daily precipitation data between 1965 and 2009 from 8 rainfall stations in Shaoguan City,the indexes of precipitation concentration degree( PCD) and precipitation concentration period( PCP) were calculated. And then inverse distance weighted( IDW) interpolation method was used to analyze the heterogeneous distribution characteristics of inter-annual precipitation by introducing the spatial distribution of annual mean values,variable coefficients,correlation coefficients with annual precipitation,change trends and composite analysis. The results showed that PCD was mainly decreasing from southeast to northwest in spatial distribution,long-term average annual values of PCP were distributed in the first ten days of June at most region. Annual precipitation increased as PCD increased in southern region,but the change trend was the opposite in northern region. Annual precipitation increased as PCP lagged in most region. PCD and PCP mainly appeared upward trend. Composite analysis of PCD in more-precipitation years was similar to less-precipitation years in spatial distribution,but the PCD in less-precipitation years was higher.Seen from the mean in the whole region,PCP in more-precipitation years lagged about 20 days behind those in less-precipitation years. The research can provide basis for the production of agriculture and industry as well as disaster prevention and reduction. 展开更多
关键词 HETEROGENEITY Precipitation concentration degree Precipitation concentration period Shaoguan City Inverse distance weighted interpolation
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Spatial variability of soil chemical properties of Moso bamboo forests of China
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作者 Regassa Terefe Kun-yong Yu +3 位作者 Yangbo Deng Xiong Yao Fan Wang Jian Liu 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第6期2599-2608,共10页
This study investigates the spatial variability of soil organic matter(SOM),soil organic carbon(SOC)and pH in the upper 20-cm layer and 20-40 cm layer in Moso bamboo(Phyllostachys pubescens Pradelle)forests using a ge... This study investigates the spatial variability of soil organic matter(SOM),soil organic carbon(SOC)and pH in the upper 20-cm layer and 20-40 cm layer in Moso bamboo(Phyllostachys pubescens Pradelle)forests using a geostatistics model.Interpolation maps of SOM,SOC,and pH were developed using ordinary kriging(OK)and inverse distance weighted(IDW)methods.The pH,SOC,and SOM of the two soil layers ranged from 4.6 to 4.7,from 1.5 to 2.7 g kg^(-1)and from 20.3 to 22.4 g kg^(-1),respectively.The coefficient of variation for SOM and SOC was 29.9-43.3%while a weak variability was found for pH.Gaussian and exponential models performed well in describing the spatial variability of SOC contents with R^(2)varying from 0.95 to 0.90.The nugget/sill values of pH are less than 25%,which indicates a strong spatial correlation,while the nugget/sill values of SOC and SOM fall under moderate spatial correlation.Interpolation using ordinary kriging and inverse distance weighted methods revealed that the spatial distribution of SOM,SOC,and pH was inconsistent due to external and internal factors across the plots.Regarding the cross-validation results,the ordinary kriging method performed better than inverse distance weighted method for selected soil properties.This study suggests that the spatial variability of soil chemical properties revealed by geostatistics modeling will help decision-makers improve the management of soil properties. 展开更多
关键词 Cross-validation Geostatistics Inverse distance weighted Ordinary kriging Semi-variance
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Trends and Geostatistical Interpolation of Spatio-Temporal Variability of Precipitation in Northern Cameroon
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作者 Elisabeth Fita Dassou Auguste Ombolo +3 位作者 Steven Chouto Guillaume Ewodo Mboudou Jean Marcel Abate Essi Etienne Bineli 《American Journal of Climate Change》 2016年第2期229-244,共16页
This paper examines the spatial and temporal variability of the mean annual precipitation in the Northern Cameroon on the context of climate change during the time period 1950-2013. The study used homogeneous monthly ... This paper examines the spatial and temporal variability of the mean annual precipitation in the Northern Cameroon on the context of climate change during the time period 1950-2013. The study used homogeneous monthly and annual precipitations database of twenty-five stations located in the Northern Cameroon and Southern Chad Republic. Geostatisticals interpolation methods (Kriging and Inverse Distance Weighting method) associated with Digital Elevation Model were used to establish the spatial distribution of annuals precipitations. The non-parametric Mann- Kendall test and Sen’s slope method were performed to determine respectively trend and magnitude. The result indicates a spatial distribution of precipitation mainly determined by the topography and the geography of the study area. The trend analysis shows a decrease of annual average precipitation across the Northern Cameroon at a rate of ?0.568 mm/year over the time period 1950-2013. The magnitude of decreasing trends ranged between 0.11 and 3.92 mm/year. Statistically significant decreasing trends at the 95% level of confidence were noted at 10% while 5% of stations showed statistically significant increasing. However, 60% of stations indicate a decreasing trend. Monthly analysis of rainfall shows a decreasing trend during June and September while July and August present an increasing trend. 展开更多
关键词 PRECIPITATION KRIGING Inverse distance Weighting Mann-Kendall Test TRENDS Northern Cameroon
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Spatio-Temporal Air Pollutant Characterization for Urban Areas
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作者 Nurainshafika Sahak Arnis Asmat Noor Zaitun Yahaya 《Journal of Geoscience and Environment Protection》 2022年第1期218-237,共20页
Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been ad... Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been adequately addressed in the data Spatio-temporal time series. Thus, this study was intended to characterize the effect of urbanization on air pollution for an urbanized Klang Valley, Malaysia using Spatio-temporal data from 2008 to 2017. The Air Pollution Index (API) data and local pollutant concentration were employed to establish the links between urban air pollution. The analysis will be supported by determining the source of pollutants during the study period using</span></span><span><span><span style="font-family:""> Principal Component Analysis (PCA)</span></span></span><span><span><span style="font-family:"">.</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">The study identified </span></span></span><span><span><span style="font-family:"">that Carbon monoxide (CO), Nitrogen Dioxide (NO<sub>2</sub>), and Ozone (O<sub>3</sub>) are </span></span></span><span><span><span style="font-family:"">the major air pollution that has contributed to degrading air quality in the Klang Valley due to the vehicles, combustion process, and industries. 展开更多
关键词 Urban Pollution Air Pollution Index (API) Spatio-Temporal Characterization Source of Pollutants Inverse distance weighted (IDW) Principal Component Analysis (PCA)
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Mapping of Precipitation, Temperature and Evaporation Distributions in the Porsuk Basin Using Distant Forecasting Methods
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作者 Recep Bakis Yildirim Bayazit +1 位作者 Hakan Uygucgil Cengiz Koc 《Computational Water, Energy, and Environmental Engineering》 2017年第4期321-350,共30页
Geographical data are of great importance in meteorology and climate science. These data can create the areal distribution models analyzed by spatial interpolation methods. The values of the areas without measurement ... Geographical data are of great importance in meteorology and climate science. These data can create the areal distribution models analyzed by spatial interpolation methods. The values of the areas without measurement data are estimated with these distribution models. In this study, distribution of meteorological parameters such as precipitation, temperature and evaporation in Porsuk basin, which is determined as research area, was investigated by Inverse Distance Weighting (IDW) and Ordinary Kriging methods. Actual meteorological data analyzed of the basin do not show a normal distribution statistically. Therefore, the data were firstly subjected to normalization and then analyzed according to the IDW and Ordinary Kriging methods to create distribution maps of precipitation, temperature and evaporation data. Quadratic mean error values were compared to investigate the reliability of analyzes. In this study, the analysis results of precipitation, temperature and evaporation data have been calculated by two different methods. Ordinary Kriging method has been determined as the method making the most accurate estimation. 展开更多
关键词 Geographical Information Systems Inverse distance Weighting Ordinary Kriging METEOROLOGY Porsuk Basin TURKEY
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