期刊文献+
共找到210,067篇文章
< 1 2 250 >
每页显示 20 50 100
Predicting Standardized Precipitation Evapotranspiration Index for Fada N’Gourma by 2050 Using CMPI-6 Outputs under SSPs Scenarios
1
作者 Tog-Noma Patricia Emma Bontogho Andrew Ireson +1 位作者 Dominic Boateng-Gyambiby Abdullahi Dini 《Journal of Environmental Science and Engineering(A)》 CAS 2025年第1期31-42,共12页
Extreme weather events,such as floods and droughts,are expected to rise significantly worldwide as a result of climate change.Investigating future drought patterns is therefore a key approach for elaborating anticipat... Extreme weather events,such as floods and droughts,are expected to rise significantly worldwide as a result of climate change.Investigating future drought patterns is therefore a key approach for elaborating anticipatory water resources management responses to climate change.In this paper,future meteorological drought conditions are investigated based on the SPEI(Standardised Precipitation Evapotranspiration Index).This study makes use of observed and projected data.The simulated data were retrieved from the CMIP6(Coupled Model Intercomparison Project Phase 6)over the period 2025-2050,and the Delta change method was adopted to remove the bias in the dataset.Then SPEI at various scales has been estimated under four future scenarios(SSP1-2.6,SSP2-4.5,SSP3-7.0 and SSP5-8.5).The trend analysis of the projected SPEI was performed at p<0.05 using the MMK(Modified Mann-Kendall)test in order to detect the statistically significant trend of the drought against the null hypothesis of no trend.Results show large variability in the magnitude of drought in the past and future.Based on SPEI at 24 months accumulation,the result shows that under SSP1-2.6,the basin will experience a wet period during the first decade(SPEI=0.60),the second decade will be dry(SPEI24=-0.43).The remaining years will be also dry(SPEI=-0.34).Under SSP2-4.5,SSP3-7.0 and SSP5-8.5 scenarios,the district will experience a wet period during the first two decades with SPEI ranging from 0.38 to 0.59.This wet period will be followed by a dry period under these scenarios ranging from-0.14 to-0.06.Overall,under SSPs scenarios,two main periods characterized by a rainfall recovery spanning from followed by a moderately prolonged drought are identified within the study area.The findings of this study may provide valuable information for developing proactive measures to reduce water insecurity in Fada N’Gourma through effective drought mitigation. 展开更多
关键词 Climate change drought index CMPI-6 Fada N’Gourma SSP-scenarios.
下载PDF
Impact of triglyceride-glucose index on the long-term prognosis of advanced gastric cancer patients receiving immunotherapy combined with chemotherapy
2
作者 Zhi-Yuan Yao Xiao Ma +3 位作者 Yong-Zheng Cui Jie Liu Zheng-Xiang Han Jun Song 《World Journal of Gastroenterology》 2025年第5期68-83,共16页
BACKGROUND Gastric cancer(GC)is the fifth most common malignancy and the third leading cause of death worldwide.Despite advancements in immunotherapies,patient prognosis remains poor,necessitating the identification o... BACKGROUND Gastric cancer(GC)is the fifth most common malignancy and the third leading cause of death worldwide.Despite advancements in immunotherapies,patient prognosis remains poor,necessitating the identification of key prognostic factors to optimize the treatment approaches.Insulin resistance,as indicated by the triglyceride glucose(TyG)index,is increasingly recognized for its impact on cancer progression and immune modulation,and its potential role in GC prognosis is of particular interest.AIM To investigate whether the TyG index,a surrogate marker of insulin resistance,can predict the prognosis of patients with advanced GC receiving immunotherapy combined with chemotherapy.METHODS This retrospective study included 300 patients with advanced GC who received sintilimab combined with chemotherapy.The patients were categorized into two groups according to high or low TyG index,and independent prognostic factors for overall survival(OS)were determined using Cox proportional hazards regression analysis,which led to the development of a nomogram model.RESULTS Of the included patients,136 had a high TyG index and 164 had a low TyG index.The median progression-free survival of the high TyG index group was significantly longer than that of the low TyG index group.Similarly,the median OS of the high TyG index group was significantly longer than that of the low TyG index group.The ob-jective response and disease control rates in the two groups were 18.38%vs 9.15%and 58.82%vs 46.95%,res-pectively.No significant difference was noted in the incidence of adverse reactions at any level between the two groups(P>0.05).In multivariate analysis,the Eastern Cooperative Oncology Group score,programmed cell death ligand 1 expression,and TyG index acted as independent prognostic factors for OS.Of these factors,the hazard ratio of the TyG index was 0.36(95%confidence interval:0.36-0.55,P<0.001),and the nomogram model re-emphasized its importance as the main predictor of patient prognosis,followed by programmed cell death ligand 1 expression and the Eastern Cooperative Oncology Group score.CONCLUSION The TyG index is a long-term predictor of the efficacy of immunotherapy combined with chemotherapy,and patients with a high index have a better prognosis. 展开更多
关键词 Triglyceride glucose index Gastric cancer Sintilimab Prognostic model Efficacy Safety
下载PDF
Prognostic roles nutritional index in patients with resectable and advanced biliary tract cancers
3
作者 Di Zeng Ning-Yuan Wen +2 位作者 Yao-Qun Wang Nan-Sheng Cheng Bei Li 《World Journal of Gastroenterology》 2025年第6期76-88,共13页
BACKGROUND Biliary tract cancer(BTC)is a rare,aggressive malignancy with increasing inci-dence and poor prognosis.Identifying preoperative prognostic factors is crucial for effective risk-benefit assessments and patie... BACKGROUND Biliary tract cancer(BTC)is a rare,aggressive malignancy with increasing inci-dence and poor prognosis.Identifying preoperative prognostic factors is crucial for effective risk-benefit assessments and patient stratification.The prognostic nutritional index(PNI),which reflects immune-inflammatory and nutritional status,has shown prognostic value in various cancers,but its significance in BTC remains unclear.AIM To assess the prognostic value of the preoperative PNI in BTC patients,with a focus on overall survival(OS)and disease-free survival(DFS).METHODS Comprehensive searches were conducted in the PubMed,EMBASE,and Web of Science databases from inception to April 2024.The primary outcomes of interest focused on the associations between the preoperative PNI and the prognosis of BTC patients,specifically OS and disease-free survival(DFS).Statistical analyses were conducted via STATA 17.0 software.RESULTS Seventeen studies encompassing 4645 patients met the inclusion criteria.Meta-analysis revealed that a low PNI was significantly associated with poorer OS[hazard ratio(HR)1.91,95%CI:1.59-2.29;P<0.001]and DFS(HR 1.93,95%CI:1.39-2.67;P<0.001).Subgroup analyses revealed consistent results across BTC subtypes(cholangiocarcinoma and gallbladder cancer)and stages(resectable and advanced).Sensitivity analyses confirmed the robustness of these findings,and no significant publication bias was detected.CONCLUSION This study demonstrated that a low preoperative PNI predicts poor OS and DFS in BTC patients,highlighting its potential as a valuable prognostic tool.Further prospective studies are needed to validate these findings and enhance BTC patient management. 展开更多
关键词 Biliary tract cancer Prognostic nutritional index Predictive marker META-ANALYSIS Survival outcomes
下载PDF
Diagnostic implications of neutrophil-to-lymphocyte ratio,platelet-tolymphocyte ratio,and systemic immune-inflammatory index for gastric carcinoma
4
作者 Huang-Min Wu Xiao-Xuan Ying +1 位作者 Li-Li Lv Jian-Wen Hu 《World Journal of Gastrointestinal Surgery》 2025年第1期139-146,共8页
BACKGROUND The diagnosis of gastric carcinoma(GC)is essential for improving clinical outcomes.However,the biomarkers currently used for GC screening are not ideal.AIM To explore the diagnostic implications of the neut... BACKGROUND The diagnosis of gastric carcinoma(GC)is essential for improving clinical outcomes.However,the biomarkers currently used for GC screening are not ideal.AIM To explore the diagnostic implications of the neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),and systemic immune-inflammatory index(SII)for GC.METHODS The baseline data of 133 patients with GC and 134 patients with precancerous gastric conditions admitted between January 2022 and December 2023 were retrospectively analyzed.The information on peripheral blood platelet,neutrophil,and lymphocyte counts in each patient was collected,and the NLR,PLR,and SII levels of both groups were calculated.Additionally,multivariate logistic regression analysis was conducted,and the diagnostic implications of NLR,PLR,and SII in differentiating patients with precancerous gastric conditions,compared with those with GC,were analyzed through receiver operating characteristic(ROC)curves.RESULTS The data indicated that NLR,PLR,and SII had abnormally increased levels in the patients with GC.Gender and body mass index were risk factors for the occurrence of GC.ROC data revealed that the areas under the curve of three patients with precancerous gastric conditions,who were differentiated from those with GC,were 0.824,0.787,and 0.842,respectively.CONCLUSION NLR,PLR,and SII are all abnormally expressed in GC and have diagnostic implications,especially when used as joint indicators,in distinguishing patients with precancerous gastric conditions from those with GC. 展开更多
关键词 Gastric carcinoma Neutrophil-to-lymphocyte ratio Platelet-to-lymphocyte ratio Precancerous gastric conditions Systemic immune-inflammatory index
下载PDF
Association between body mass index and lumbar spine volumetric bone mineral density in diabetic and non-diabetic patients
5
作者 Fang Lv Xiao-Ling Cai +4 位作者 Xiu-Ying Zhang Xiang-Hai Zhou Xue-Yao Han Yu-Feng Li Li-Nong Ji 《World Journal of Diabetes》 2025年第2期103-113,共11页
BACKGROUND The association between body mass index(BMI)and bone mineral density(BMD)has shown inconsistent results,varying by sex and skeletal site.Despite normal or elevated bone mass,individuals with type 2 diabetes... BACKGROUND The association between body mass index(BMI)and bone mineral density(BMD)has shown inconsistent results,varying by sex and skeletal site.Despite normal or elevated bone mass,individuals with type 2 diabetes have an increased risk of hip and vertebral fractures.AIM To assess lumbar spine trabecular volumetric BMD(vBMD)across different BMI categories in individuals with and without diabetes.METHODS This cross-sectional study included 966 men over 50 years old and 1001 postmenopausal women from the Pinggu Metabolic Disease Study.The vBMD of lumbar vertebrae 2 through 4 was measured using quantitative computed tomography.Total adipose tissue,subcutaneous adipose tissue(SAT),visceral adipose tissue(VAT),and lumbar skeletal muscle area were also quantified.RESULTS In men with obesity(P=0.038)and overweight(P=0.032),vBMD was significantly higher in the diabetes group compared to non-diabetic men.After adjusting for age and sex,no significant saturation effect between BMI and BMD was found in participants with diabetes or in women without diabetes.However,a BMI threshold of 22.33 kg/m²indicated a saturation point for vBMD in nondiabetic men.Independent predictors of vBMD in men included age(r=-0.387,P<0.001),BMI(r=0.130,P=0.004),and VAT(r=-0.145,P=0.001).For women,significant predictors were age(r=-0.594,P<0.001),BMI(r=0.157,P=0.004),VAT(r=-0.112,P=0.001),and SAT(r=-0.068,P=0.035).CONCLUSION The relationship between BMI and trabecular vBMD differs in individuals with and without diabetes.Overweight and obese men with diabetes exhibit higher vBMD. 展开更多
关键词 Obesity and overweight Body mass index DIABETES Lumbar spine volumetric bone mineral density Quantitative computed tomography
下载PDF
Cross-sectional study of the association between triglyceride glucose-body mass index and obstructive sleep apnea risk
6
作者 Li Gong Ming Su +9 位作者 Jing-Han Xu Zhen-Fei Peng Lin Du Ze-Yao Chen Yu-Zhou Liu Lu-Cia Chan Yin-Luan Huang Yu-Tian Chen Feng-Yi Huang Chun-Li Piao 《World Journal of Diabetes》 2025年第3期65-75,共11页
BACKGROUND The triglyceride glucose-body mass index(TyG-BMI)is a novel indicator of insulin resistance(IR).Obstructive sleep apnea(OSA)is a prevalent disorder characterized by recurrent complete or partial collapse of... BACKGROUND The triglyceride glucose-body mass index(TyG-BMI)is a novel indicator of insulin resistance(IR).Obstructive sleep apnea(OSA)is a prevalent disorder characterized by recurrent complete or partial collapse of the pharyngeal airway during sleep;however,the relationship between these two conditions remains unexplored.We hypothesized that a higher TyG-BMI is associated with the occurrence of OSA.AIM To assess the association between TyG-BMI and OSA in adults in the United States.METHODS A cross-sectional study was conducted utilizing data from the National Health and Nutrition Examination Surveys spanning from 2005-2008 to 2015-2018.TyGBMI was calculated as Ln[triglyceride(mg/dL)×fasting blood glucose(mg/dL)/2]×BMI.Restricted cubic splines were used to analyze the risk of TyG-BMI and OSA occurrence.To identify potential nonlinear relationships,we combined Cox proportional hazard regression with smooth curve fitting.We also conducted sensitivity and subgroup analyses to verify the robustness of our findings.RESULTS We included 16794 participants in the final analysis.Multivariate regression analysis showed that participants with a higher TyG-BMI had a higher OSA incidence.After adjusting for all covariates,TyG-BMI was positively correlated with the prevalence of OSA(odds ratio:1.28;95%confidence interval:1.17,1.40;P<0.001);no significant nonlinear relationship was observed.Subgroup analysis showed no strong correlation between TyG-BMI and OSA in patients with diabetes.The correlation between TyG-BMI and OSA was influenced by age,sex,smoking status,marital status,hypertensive stratification,and obesity;these subgroups played a moderating role between TyGBMI and OSA.Even after adjusting for all covariates,there was a positive association between TYG-BMI and OSA prevalence.CONCLUSION A higher TyG-BMI index is linked to higher chances of developing OSA.As TyG-BMI is an indicator of IR,managing IR may help reduce the risk of OSA. 展开更多
关键词 Obstructive sleep apnea Triglyceride glucose-body mass index Insulin resistance CROSS-SECTIONAL National Health and Nutrition Examination Surveys
下载PDF
A cross-sectional study of the association between dietary inflammatory index and glaucoma prevalence in a US population
7
作者 Wen-Li Chen Li-Xia Zhang 《International Journal of Ophthalmology(English edition)》 2025年第1期139-145,共7页
AIM:To assess the relationship between dietary inflammatory index(DII)and prevalence of glaucoma among individuals aged 40y and above in the United States.METHODS:Participants were drawn from 2 cycles of the National ... AIM:To assess the relationship between dietary inflammatory index(DII)and prevalence of glaucoma among individuals aged 40y and above in the United States.METHODS:Participants were drawn from 2 cycles of the National Health and Nutrition Examination Survey(NHANES,2005-2008)for a cross-sectional study.DII was calculated from 24-hour dietary recall questionnaire conducted by experienced researchers and data analyzed in R according to the NHANES user guide,“Stratified Multi-stage Probability Sampling”.The relationship between DII and glaucoma was evaluated by multi-factor logistic regression analysis and the existence of a non-linear association examined by restricted cubic spline(RCS)analysis.RESULTS:A total of 5359 subjects were included and the cross-sectional analysis weighted to represent the US population of 109 million.DII was elevated in glaucoma patients(P<0.001)and smoking and alcohol use contributed to significant differences(P<0.001).DII correlated negatively with Healthy Eating Index(HEI)-2015(Spearman rank correlation coefficient,r=-0.49).RCS analysis showed a linear relationship between DII and glaucoma risk(P of non-linear relationship=0.575).CONCLUSION:An increased DII is strongly associated with high risk of glaucoma and diet-induced inflammation should be controlled to delay glaucoma progression. 展开更多
关键词 glaucoma risk factors dietar y inflammatory index National Health and Nutrition Examination Survey restricted cubic spline regression cross-sectional study
下载PDF
基于改进Sparse Indexing的多负载消冗方法
8
作者 王灿 秦志光 +1 位作者 杨磊 杨皓 《电子科技大学学报》 EI CAS CSCD 北大核心 2013年第5期734-739,共6页
针对现有的Sparse Indexing方法不能有效处理小文件备份负载的问题,提出了一种以Broder扩展定理为理论依据的最小特征采样算法,该算法可以对不同形式的备份负载进行有效的特征采样。在此算法的基础上,设计了一种多负载重复数据消除方法... 针对现有的Sparse Indexing方法不能有效处理小文件备份负载的问题,提出了一种以Broder扩展定理为理论依据的最小特征采样算法,该算法可以对不同形式的备份负载进行有效的特征采样。在此算法的基础上,设计了一种多负载重复数据消除方法,该方法通过对备份负载进行特征采样,仅在内存中维护完整索引的一个很小的子集,并通过批量读入分块标识符,摊销了磁盘访问开销,提高了吞吐量。实验结果表明,该方法对混合备份负载的压缩比是Sparse Indexing的2.04倍,而吞吐量与Sparse Indexing相当。该方法适用于需要处理多种形式备份负载的高性能重复数据消除系统。 展开更多
关键词 重复数据消除 磁盘瓶颈 最小特征采样 稀疏索引 吞吐量
下载PDF
DYNAMIC RESPONSE OF ROLLER GEAR INDEXING CAM SYSTEM CONSIDERING CLEARANCE AND MOTOR CHARACTERISTIC 被引量:4
9
作者 Chang Zongyu Civil Aviation College,Nanjing University of Aeronautics and Astronautics Zhang Ce Yang Yuhu Wang Yuxin Tianjin University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2001年第2期189-192,共4页
The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexib... The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexibility are developed and solved.The results show that clearance affects primarily the response on turret,and has little effects on the responses on rotary table.At the same time,the velocity fluctuation of motor shaft is not serious for the existence of inertia of reducer,and the high frequency of velocity fluctuation of camshaft is related with the torsion stiffness of shaft and the clearance between pairs. 展开更多
关键词 Roller gear indexing cam mechanism CLEARANCE Motor characteristic Dynamic response
下载PDF
Compressive Sensing Approach in Multicarrier Sparsely Indexing Modulation Systems 被引量:1
10
作者 Mostafa Salah Osama A.Omer Usama S.Mohamed 《China Communications》 SCIE CSCD 2017年第11期151-166,共16页
recently the indexed modulation(IM) technique in conjunction with the multi-carrier modulation gains an increasing attention. It conveys additional information on the subcarrier indices by activating specific subcarri... recently the indexed modulation(IM) technique in conjunction with the multi-carrier modulation gains an increasing attention. It conveys additional information on the subcarrier indices by activating specific subcarriers in the frequency domain besides the conventional amplitude-phase modulation of the activated subcarriers. Orthogonal frequency division multiplexing(OFDM) with IM(OFDM-IM) is deeply compared with the classical OFDM. It leads to an attractive trade-off between the spectral efficiency(SE) and the energy efficiency(EE). In this paper, the concept of the combinatorial modulation is introduced from a new point of view. The sparsity mapping is suggested intentionally to enable the compressive sensing(CS) concept in the data recovery process to provide further performance and EE enhancement without SE loss. Generating artificial data sparsity in the frequency domain along with naturally embedded channel sparsity in the time domain allows joint data recovery and channel estimation in a double sparsity framework. Based on simulation results, the performance of the proposed approach agrees with the predicted CS superiority even under low signal-to-noise ratio without channel coding. Moreover, the proposed sparsely indexed modulation system outperforms the conventional OFDM system and the OFDM-IM system in terms of error performance, peak-to-average power ratio(PAPR) and energy efficiency under the same spectral efficiency. 展开更多
关键词 indexed modulation combinatorial modulation double sparsity critical sparsity sparsely indexed modulation OFDM-IM
下载PDF
A Parallel Indexing Cam Mechanism with Internal Placed Followers 被引量:1
11
作者 ZHANG Yuhua REN Guangfa (School of Mechanical Engineering,Anhui University of Technology,Ma’anshan 243002,China 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S2期533-537,共5页
A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The eq... A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The equations for working pro- file and pressure angle of the cam are derived based on the inverse model and the derivative of pitch curve of cams.An example is given and demonstrates that it is available to design the new mechanism using the derived expressions. 展开更多
关键词 CAM MECHANISM PARALLEL indexing CAM INTERNAL CAM MECHANISM synthesis INTERNAL placed FOLLOWERS
下载PDF
Structural Indexing for 3D Solid Digital Library 被引量:1
12
作者 Han Shui\|hua, Lu Zheng\|ding, Chen Chuan\|bo Department of Computer Engineering, Huazhong University of Science and Teclonogy, Wuhan 430074,Chian 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期438-442,共5页
In a very large digital library that support computer aided collaborative design, an indexing process is crucial whenever the retrieval process has to select among many possible designs. In this paper, we address the... In a very large digital library that support computer aided collaborative design, an indexing process is crucial whenever the retrieval process has to select among many possible designs. In this paper, we address the problem of retrieving important design and engineering information by structural indexing. A design is represented by a model dependency graph, therefor, the indexing problem is to determine whether a graph is present or absent in a database of model dependency graphs. we present a novel graph indexing method using polynomial characterization of a model dependency graph and on hashing. Such an approach is able to create an high efficient 3D solid digital library for retrieving and extracting solid geometric model and engineering information. 展开更多
关键词 digital library computer aided design model dependency graphs HASHING indexing
下载PDF
Melanophore Indexing:A New Bio-assay Technique for the Analysis of Acute Heavy Metal (HgCl_2) Toxicity 被引量:2
13
作者 M. T. RAJAN AND T. K. BANERJEE (Histochemistry and Histopathology Laboratory, Department of Zoology,Banaras Hindu University, Varanasi 221 005, India)(Corresponding author, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1995年第3期226-231,共6页
Toxicity of 0.3 ppm (96 h LC50 value) and 0.03 ppm of mercuric chloride on the melanophores of the skin at different time intervals has been studied. Mercury treatment causes immediate increase in the number and size ... Toxicity of 0.3 ppm (96 h LC50 value) and 0.03 ppm of mercuric chloride on the melanophores of the skin at different time intervals has been studied. Mercury treatment causes immediate increase in the number and size of the pigment cells. Subsequently these pigment cells form a dense matting of melanophore network with their cell processes intellacing with those of their neighbours. These cells later show degeneration and lysis releasing large quantity of pigment granules into the intercellular spaces in the dermis.Later the pigment cells regenerate several times each followed by degeneration in a cyclic manner. Prolonged treatment with subletha. concentration of mercuric chloride does not show significant alteration in the melanophore density and size. Statistical analysis and wide spread destruction of melanophores observed during 4-6 days of exPosure might help in testing water samples contaminated with lethal concentration of heavy metal salts 展开更多
关键词 In Melanophore indexing TOXICITY HgCl2
下载PDF
Analysis and Design of the Globoidal Indexing Cam Mechanism 被引量:3
14
作者 FU Yan ming School of Mechanical and Electronic Engineering and Automation, Shanghai University, Shanghai 200072, China 《Advances in Manufacturing》 2000年第1期54-59,共6页
We first design and analyze the contour surface of the globoidal indexing cam with the aid of computer, and then do optimum design according to the requirements of dynamics. Finally, we discuss the problem of the pres... We first design and analyze the contour surface of the globoidal indexing cam with the aid of computer, and then do optimum design according to the requirements of dynamics. Finally, we discuss the problem of the pressure angle of the globoidal indexing cam mechanism in detail and put forward a new concept of equivalent pressure angle. 展开更多
关键词 globoidal indexing cam analysis of cam mechanism design of cam mechanism dynamics of mechanism pressure angle
下载PDF
Spatial/temporal indexing and information visualization genre for environmental digital libraries 被引量:3
15
作者 CHEN Su-shing GRUNWALD Sabine 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第11期1235-1248,共14页
Protecting and preserving our environmental systems require the ability to understand the spatio-temporal distri- bution of soils, parent material, topography, and land cover as well as the effects of human activities... Protecting and preserving our environmental systems require the ability to understand the spatio-temporal distri- bution of soils, parent material, topography, and land cover as well as the effects of human activities on ecosystems. Space-time modelling of ecosystems in an environmental digital library is essential for visualizing past, present, and future impacts of changes occurring within such landscapes (e.g., shift in land use practices). In this paper, we describe three novel features, spa- tio-temporal indexing, visualization, and geostatistical genre, for the environmental digital library, Environmental Visualization and Geographic Enterprise System (ENVISAGE), currently in progress at the University of Florida. 展开更多
关键词 Spatio-temporal indexing GEOSTATISTICS GIS (Geographic Information System) Visualization Environmentaldigital library Spatio-temporal search
下载PDF
A new approach for effectively determining fracture network connec- tions in fractured rocks using R tree indexing 被引量:2
16
作者 LIU Hua-mei WANG Ming-yu SONG Xian-feng 《Journal of Coal Science & Engineering(China)》 2011年第4期401-407,共7页
Determinations of fracture network connections would help the investigators remove those "meaningless" no-flow-passing fractures, providing an updated and more effective fracture network that could considerably impr... Determinations of fracture network connections would help the investigators remove those "meaningless" no-flow-passing fractures, providing an updated and more effective fracture network that could considerably improve the computation efficiency in the pertinent numerical simulations of fluid flow and solute transport. The effective algorithms with higher computational efficiency are needed to accomplish this task in large-scale fractured rock masses. A new approach using R tree indexing was proposed for determining fracture connection in 3D stochastically distributed fracture network. By com- paring with the traditional exhaustion algorithm, it was observed that from the simulation results, this approach was much more effective; and the more the fractures were investigated, the more obvious the advantages of the approach were. Furthermore, it was indicated that the runtime used for creating the R tree indexing has a major part in the total of the runtime used for calculating Minimum Bounding Rectangles (MBRs), creating the R tree indexing, precisely finding out fracture intersections, and identifying flow paths, which are four important steps to determine fracture connections. This proposed approach for the determination of fracture connections in three-dimensional fractured rocks are expected to provide efficient preprocessing and critical database for practically accomplishing numerical computation of fluid flow and solute transport in large-scale fractured rock masses. 展开更多
关键词 fracture network connection fractured rooks R tree indexing
下载PDF
Study on semantic-oriented hybrid indexing strategy of resource metadata in peer-to-peer network 被引量:1
17
作者 LIU Zhen ZHOU Mao-wei +1 位作者 HUANG Hong-bin LUO Xue-shan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期88-94,共7页
Applying ontology to describe resource metadata richly in the peer-to-peer environment has become current research trend. In this semantic peer-to-peer environment, indexing semantic element of resource description to... Applying ontology to describe resource metadata richly in the peer-to-peer environment has become current research trend. In this semantic peer-to-peer environment, indexing semantic element of resource description to support efficient resource location is a difficult and challenging problem. This paper provided a hybrid indexing architecture, which combines local indexing and global indexing. It uses community strategy and semantic routing strategy to organize key layer metadata element and uses DHT (distributed hash table) to index extensional layer metadata element. Compared with related system, this approach is more efficient in resource location and more scalable. 展开更多
关键词 Peer-to-peer (P2P) ONTOLOGY METADATA Resource indexing
下载PDF
Prediction for Dynamic Characteristics of Ring-Plate Planetary Indexing Cam Mechanism 被引量:2
18
作者 宋轶民 田广才 +2 位作者 张俊 刘明涛 刘建平 《Transactions of Tianjin University》 EI CAS 2009年第4期249-254,共6页
This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmissio... This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmission structure. Firstly, the geometry and structure of the mechanism are discussed and the kinematic practicability is simulated with virtual prototype design. Then a 3D finite element model of the ring-plate planetary indexing cam mechanism is developed with the commercial software of MATLAB and ANSYS. Through the finite element analysis, the natural frequencies and the corresponding mode shapes are predicted in one motion cycle. On the basis of the virtual prototype design and finite element analysis, an experimental prototype is made and tested to validate the prediction of the dynamic characteristics. The agreement between experimental results and the finite element analysis testifies that the finite element model developed is applicable to the prediction of the dynamic characteristics of this type of mechanism. 展开更多
关键词 ring-plate planetary indexing cam mechanism virtual prototype design finite element mode analysis
下载PDF
Ambient Air Quality Surveillance and Indexing in and around Mining Clusters in Western Kachchh Region, Gujarat, India 被引量:1
19
作者 B. Anjan Kumar Prusty 《Open Journal of Air Pollution》 2012年第2期22-30,共9页
Generation of baseline information about ambient air quality of any given region assumes significance, when the area is 1) an active mine site, 2) proposed to be mined out in future, and 3) industrialization in the ar... Generation of baseline information about ambient air quality of any given region assumes significance, when the area is 1) an active mine site, 2) proposed to be mined out in future, and 3) industrialization in the area is in fast pace. Ambient air quality monitoring (with respect to SPM, RPM, SO2, NOx and CO) was carried out in and around two mining complexes in western parts of Kachchh district in Gujarat to generate baseline air quality status of the area. This area has two major mine complexes and various large scale industrial projects (thermal power plants, cement plants and several ports and jetties) are also in pipeline. Ambient air sampling was carried out in eight locations within five km radial distance from two major mine sites, i.e. Panandhro and Mata-na-Madh, with four locations for each mine site. Air Quality Indexing was done for all the locations, since it is a simplest way for the prediction of ambient air quality status of any region with respect to industrial, residential and rural areas. Of the eight locations studied the air quality for six locations fell under fairly clean (Light Air Pollution, AQI 25-50) category, while the rest (rural areas in the region), had relatively better air quality and fell under clean (Clean Air, AQI 10-25) category. 展开更多
关键词 AIR QUALITY index Ambient AIR QUALITY MINING WESTERN KACHCHH
下载PDF
Indexing of Content-Based Image Retrieval System with Image Understanding Approach
20
作者 李学龙 刘政凯 俞能海 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第2期63-68,共6页
This paper presents a novel efficient semantic image classification algorithm for high-level feature indexing of high-dimension image database. Experiments show that the algorithm performs well. The size of the train ... This paper presents a novel efficient semantic image classification algorithm for high-level feature indexing of high-dimension image database. Experiments show that the algorithm performs well. The size of the train set and the test set is 7 537 and 5 000 respectively. Based on this theory, another ground is built with 12,000 images, which are divided into three classes: city, landscape and person, the total result of the classifications is 88.92%, meanwhile, some preliminary results are presented for image understanding based on semantic image classification and low level features. The groundtruth for the experiments is built with the images from Corel database, photos and some famous face databases. 展开更多
关键词 Content-based image retrieval Image classification Image indexing.
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部