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Intelligent Multivariable Modeling of Blast Furnace Molten Iron Quality Based on Dynamic AGA-ANN and PCA 被引量:4
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作者 Meng YUAN Ping ZHOU +3 位作者 Ming-liang LI Rui-feng LI Hong WANG Tian-you CHAI 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2015年第6期487-495,共9页
Blast furnace (BF) ironmaking process has complex and nonlinear dynamic characteristics. The molten iron temperature (MIT) as well as Si, P and S contents of molten iron is difficult to be directly measured online... Blast furnace (BF) ironmaking process has complex and nonlinear dynamic characteristics. The molten iron temperature (MIT) as well as Si, P and S contents of molten iron is difficult to be directly measured online, and large-time delay exists in offline analysis through laboratory sampling. A nonlinear multivariate intelligent modeling method was proposed for molten iron quality (MIQ) based on principal component analysis (PCA) and dynamic ge- netic neural network. The modeling method used the practical data processed by PCA dimension reduction as inputs of the dynamic artificial neural network (ANN). A dynamic feedback link was introduced to produce a dynamic neu- ral network on the basis of traditional back propagation ANN. The proposed model improved the dynamic adaptabili- ty of networks and solved the strong fluctuation and resistance problem in a nonlinear dynamic system. Moreover, a new hybrid training method was presented where adaptive genetic algorithms (AGA) and ANN were integrated, which could improve network convergence speed and avoid network into local minima. The proposed method made it easier for operators to understand the inside status of blast furnace and offered real-time and reliable feedback infor- mation for realizing close-loop control for MIQ. Industrial experiments were made through the proposed model based on data collected from a practical steel company. The accuracy could meet the requirements of actual operation. 展开更多
关键词 molten iron quality blast furnace nonlinear multivariate modeling dynamic neural network principalcomponent analysis adaptive genetic algorithm
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Solid fuel use and heart disease in middle-aged and older Chinese populations:a prospective cohort study
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作者 Jun-Wen WANG Ke-Xin CHEN +8 位作者 Teng HU Yu-Yang YE Yi-Fei ZHAO Xin-Ru HU Jiang YU Simayi Abulikemu Mai-Lin WEI Jun MA Yong PENG 《Journal of Geriatric Cardiology》 2026年第2期100-112,共13页
BACKGROUND Solid fuel use for cooking and heating is a major environmental risk factor,yet its association with new-onset heart disease(HD)remains unclear.The aim of this study was to investigate the relationship betw... BACKGROUND Solid fuel use for cooking and heating is a major environmental risk factor,yet its association with new-onset heart disease(HD)remains unclear.The aim of this study was to investigate the relationship between solid fuel exposure and new-onset HD in a large cohort.METHODS Multivariable logistic regression models assessed associations between cooking/heating fuel types(coal,crop residue/wood,liquefied petroleum gas,natural gas,and others)and new-onset HD.Subgroup analyses explored effect modification by age,sex,education,smoking,alcohol use,and region.RESULTS A prospective cohort study included 5915 participants,with 781 participants(13.2%)developing new-onset HD.Coal use for cooking showed an initial association with new-onset HD risk(OR=1.41,95%CI:1.06–1.86,P=0.02),which attenuated after full adjustment(OR=1.28,95%CI:0.96–1.72,P=0.10).Coal use for heating demonstrated robust associations across all models(OR=1.86,95%CI:1.42–2.43,P<0.001).Crop residue/wood burning for heating was also significant(Model 2:OR=1.40,95%CI:1.06–1.86,P=0.02).Subgroup analyses revealed stronger associations among females,non-smokers,non-drinkers,and less-educated participants.Geographic stratification showed significant associations in southern but not northern regions.CONCLUSIONS Solid fuel use,particularly coal for heating,is associated with increased new-onset HD risk.Reducing solid fuel exposure is crucial for HD prevention in low-resource settings. 展开更多
关键词 petroleum gasnatural gasand solid fuel multivariable logistic regression models older populations middle aged heart disease prospective cohort study effect modificatio
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Evaluation and forecast of the regional marine innovation ecosystem’s competitiveness:A systematic multivariate grey interval model with spatial proximity effects
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作者 LI Xuemei LI Na DING Song 《Journal of Geographical Sciences》 2026年第2期363-398,共36页
Establishing a Regional Marine Innovation Ecosystem(RMIE)is crucial for advancing China’s maritime power strategy.Concurrently,developing a competitive RMIE serves as a strategic lever to enhance the global competiti... Establishing a Regional Marine Innovation Ecosystem(RMIE)is crucial for advancing China’s maritime power strategy.Concurrently,developing a competitive RMIE serves as a strategic lever to enhance the global competitiveness of China’s marine science sector.However,research on the competitiveness of RMIE is limited.To this end,this study constructs an evaluation index system based on ecological niche theory to assess the competitiveness of RMIE in China from 2008 to 2020.The findings indicate generally fluctuating upward trends in RMIE’s competitiveness,with Shandong,Jiangsu,and Guangdong showing relatively strong positions.Notably,there are significant intra-regional imbalances and inter-regional asynchrony in RMIE’s competitiveness across China’s three major marine economic circles.Recognizing that forecasting RMIE competitiveness can inform policy formulation,this paper proposes a systematic multivariate grey interval prediction model that incorporates spatial proximity effects.This model effectively captures the interval and uncertainty characteristics of RMIE’s competitiveness while considering spatial relationships among regions.Results from comparative analysis,robustness tests,and sensitivity analysis demonstrate its superior applicability and forecasting accuracy.Additionally,interval forecasts and scenario analyses suggest that RMIE competitiveness will maintain stable growth,although unbalanced and unsynchronized development is likely to persist.Overall,the approach developed for evaluating and forecasting RMIE competitiveness offers valuable insights for effective policy formulation. 展开更多
关键词 grey model regional marine innovation ecosystem ecological niche theory multivariate grey interval prediction model spatial proximity effects
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Fractional derivative multivariable grey model for nonstationary sequence and its application 被引量:4
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作者 KANG Yuxiao MAO Shuhua +1 位作者 ZHANG Yonghong ZHU Huimin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第5期1009-1018,共10页
Most of the existing multivariable grey models are based on the 1-order derivative and 1-order accumulation, which makes the parameters unable to be adjusted according to the data characteristics of the actual problem... Most of the existing multivariable grey models are based on the 1-order derivative and 1-order accumulation, which makes the parameters unable to be adjusted according to the data characteristics of the actual problems. The results about fractional derivative multivariable grey models are very few at present. In this paper, a multivariable Caputo fractional derivative grey model with convolution integral CFGMC(q, N) is proposed. First, the Caputo fractional difference is used to discretize the model, and the least square method is used to solve the parameters. The orders of accumulations and differential equations are determined by using particle swarm optimization(PSO). Then, the analytical solution of the model is obtained by using the Laplace transform, and the convergence and divergence of series in analytical solutions are also discussed. Finally, the CFGMC(q, N) model is used to predict the municipal solid waste(MSW). Compared with other competition models, the model has the best prediction effect. This study enriches the model form of the multivariable grey model, expands the scope of application, and provides a new idea for the development of fractional derivative grey model. 展开更多
关键词 fractional derivative of Caputo type fractional accumulation generating operation(FAGO) Laplace transform multivariable grey prediction model particle swarm optimization(PSO)
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Nonlinear multilevel seemingly unrelated height-diameter and crown length mixed-effects models for the southern Transylvanian forests,Romania
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作者 Albert Ciceu Stefan Leca +1 位作者 Ovidiu Badea Lauri Mehtatalo 《Forest Ecosystems》 2025年第4期630-641,共12页
In this study,we used an extensive sampling network established in central Romania to develop tree height and crown length models.Our analysis included more than 18,000 tree measurements from five different species.In... In this study,we used an extensive sampling network established in central Romania to develop tree height and crown length models.Our analysis included more than 18,000 tree measurements from five different species.Instead of building univariate models for each response variable,we employed a multivariate approach using seemingly unrelated mixed-effects models.These models incorporated variables related to species mixture,tree and stand size,competition,and stand structure.With the inclusion of additional variables in the multivariate seemingly unrelated mixed-effects models,the accuracy of the height prediction models improved by over 10% for all species,whereas the improvement in the crown length models was considerably smaller.Our findings indicate that trees in mixed stands tend to have shorter heights but longer crowns than those in pure stands.We also observed that trees in homogeneous stand structures have shorter crown lengths than those in heterogeneous stands.By employing a multivariate mixed-effects modelling framework,we were able to perform cross-model random-effect predictions,leading to a significant increase in accuracy when both responses were used to calibrate the model.In contrast,the improvement in accuracy was marginal when only height was used for calibration.We demonstrate how multivariate mixed-effects models can be effectively used to develop multi-response allometric models that can be easily calibrated with a limited number of observations while simultaneously achieving better-aligned projections. 展开更多
关键词 Multivariate model Cross-model calibration Crown allometry Multilevel model Mixed stands Heterogeneous stand structure
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Quantifying and categorizing development paths of poverty-elimination counties in China:Based on the perspective of population-land-industry
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作者 Qianxi Zhang Zhi Cao +1 位作者 Sixin Su Xuanchang Zhang 《Geography and Sustainability》 2025年第2期44-56,共13页
China has achieved the poverty reduction goal of the United Nations 2030 Agenda for Sustainable Development 10 years ahead of schedule,contributing significantly to global poverty reduction.Despite extended efforts in... China has achieved the poverty reduction goal of the United Nations 2030 Agenda for Sustainable Development 10 years ahead of schedule,contributing significantly to global poverty reduction.Despite extended efforts in poverty elimination,there is a lack of quantitative studies categorizing and comparing poverty-elimination counties(PECs)based on their processes.This study proposes an innovative framework for analyzing PECs’development paths from the perspective of population-land-industry(PLI).We quantify the PLI matching degree of PECs in China during the critical phase of the battle against poverty through a multivariate matching model,classify PECs via K-means clustering according to the consistency in PLI matching degree evolution,and summarize the typical development patterns of PECs.Results indicate that the PLI matching degree of PECs in China increased substantially from 2015 to 2020,particularly in eastern areas,while the western region,including the Qinghai-Xizang Plateau and southwestern Xinjiang,shows untapped potential for improvement.Five types of PECs are identified,with the majority(30.1%)showing sustained moderate PLI matching and a minority(9.6%)experiencing long-term PLI mismatch.Industry is the shortfall of various PECs,and effective strategies to facilitate all types of PECs include the development of emerging businesses and the expansion of secondary and tertiary industries.Additionally,enriching rural labor force and increasing farmland use efficiency are essential for optimal PLI matching and positive interaction,ultimately ensuring poverty elimination and sustainable development. 展开更多
关键词 Poverty elimination Multivariate matching model Spatial pattern Sustainable development patterns Sustainable Development Goals
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Multivariate natural gas price forecasting model with feature selection,machine learning and chernobyl disaster optimizer
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作者 Pei Du Xuan-Kai Zhang +1 位作者 Jun-Tao Du Jian-Zhou Wang 《Petroleum Science》 2025年第11期4823-4837,共15页
The significance of accurately forecasting natural gas prices is far-reaching and significant,not only for the stable operation of the energy market,but also as a key element in promoting sustainable development and a... The significance of accurately forecasting natural gas prices is far-reaching and significant,not only for the stable operation of the energy market,but also as a key element in promoting sustainable development and addressing environmental challenges.However,natural gas prices are affected by multiple source factors,presenting complex,unstable nonlinear characteristics hindering the improvement of the prediction accuracy of existing models.To address this issue,this study proposes an innovative multivariate combined forecasting model for natural gas prices.Initially,the study meticulously identifies and introduces 16 variables impacting natural gas prices across five crucial dimensions:the production,marketing,commodities,political and economic indicators of the United States and temperature.Subsequently,this study employs the least absolute shrinkage and selection operator,grey relation analysis,and random forest for dimensionality reduction,effectively screening out the most influential key variables to serve as input features for the subsequent learning model.Building upon this foundation,a suite of machine learning models is constructed to ensure precise natural gas price prediction.To further elevate the predictive performance,an intelligent algorithm for parameter optimization is incorporated,addressing potential limitations of individual models.To thoroughly assess the prediction accuracy of the proposed model,this study conducts three experiments using monthly natural gas trading prices.These experiments incorporate 19 benchmark models for comparative analysis,utilizing five evaluation metrics to quantify forecasting effectiveness.Furthermore,this study conducts in-depth validation of the proposed model's effectiveness through hypothesis testing,discussions on the improvement ratio of forecasting performance,and case studies on other energy prices.The empirical results demonstrate that the multivariate combined forecasting method developed in this study surpasses other comparative models in forecasting accuracy.It offers new perspectives and methodologies for natural gas price forecasting while also providing valuable insights for other energy price forecasting studies. 展开更多
关键词 Natural gas price forecasting Multivariate forecasting model Machine learning Chernobyl disaster optimizer
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Tumor Displacement Prediction and Augmented Reality Visualization in Brain Tumor Resection Surgery
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作者 WANG Jiayu WANG Shuyi +4 位作者 WEI Yongxu LIAO Chencong SHANG Hanbing WANG Xue KANG Ning 《Journal of Shanghai Jiaotong university(Science)》 2025年第4期733-743,共11页
The purpose of this study is to establish a multivariate nonlinear regression mathematical model to predict the displacement of tumor during brain tumor resection surgery.And the study will be integrated with augmente... The purpose of this study is to establish a multivariate nonlinear regression mathematical model to predict the displacement of tumor during brain tumor resection surgery.And the study will be integrated with augmented reality technology to achieve three-dimensional visualization,thereby enhancing the complete resection rate of tumor and the success rate of surgery.Based on the preoperative MRI data of the patients,a 3D virtual model is reconstructed and 3D printed.A brain biomimetic model is created using gel injection molding.By considering cerebrospinal fluid loss and tumor cyst fluid loss as independent variables,the highest point displacement in the vertical bone window direction is determined as the dependent variable after positioning the patient for surgery.An orthogonal experiment is conducted on the biomimetic model to establish a predictive model,and this model is incorporated into the augmented reality navigation system.To validate the predictive model,five participants wore HoloLens2 devices,overlaying the patient’s 3D virtual model onto the physical head model.Subsequently,the spatial coordinates of the tumor’s highest point after displacement were measured on both the physical and virtual models(actual coordinates and predicted coordinates,respectively).The difference between these coordinates represents the model’s prediction error.The results indicate that the measured and predicted errors for the displacement of the tumor’s highest point on the X and Y axes range from−0.6787 mm to 0.2957 mm and−0.4314 mm to 0.2253 mm,respectively.The relative errors for each experimental group are within 10%,demonstrating a good fit of the model.This method of establishing a regression model represents a preliminary attempt to predict brain tumor displacement in specific situations.It also provides a new approach for surgeons.By combining augmented reality visualization,it addresses the need for predicting tumor displacement and precisely locating brain anatomical structures in a simple and cost-effective manner. 展开更多
关键词 brain tumor intraoperative displacement biomimetic model multivariate nonlinear regression model augmented reality prediction error
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Preventive of deep vein thrombosis in cancer patients after peripherally inserted central catheter catheterization using a diversified comprehensive teaching model
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作者 Xiao-Ying Zhao Yan-Yu Lu +2 位作者 Xian Hong Xiao-Yan Wu Mei-Fang Ruan 《World Journal of Gastrointestinal Surgery》 2025年第11期308-315,共8页
BACKGROUND Peripherally inserted central catheter(PICC)is the preferred intravenous route for chemotherapy in patients with cancer,but its complications,especially deep vein thrombosis(DVT),are becoming increasingly p... BACKGROUND Peripherally inserted central catheter(PICC)is the preferred intravenous route for chemotherapy in patients with cancer,but its complications,especially deep vein thrombosis(DVT),are becoming increasingly prevalent.Medical staff proficient in intubation and maintenance techniques can reduce complications.The multivariate integration teaching model applies the integration of“teaching learning application”to medical training,which helps shift the prevention of complications from“passive management of complications”to“active construction of risk immunity”,thereby ensuring foundational competency for PICC in patients with cancer.AIM To investigate the efficacy of the multivariate integration teaching model in patients with gastric cancer and concurrent DVT after PICC intubation and analyze its effect on patients’quality of life index(QLI)and satisfaction.METHODS A retrospective analysis of medical records of 100 patients with gastric cancer and PICC treated at Zhejiang Provincial People’s Hospital from May 2019 to November 2020 was conducted.According to the different treatment methods and teaching modes received by medical staff,they were divided into a control group and an experimental group,with 50 cases in each group.The routine clinical teaching model and the multivariate integration teaching model were administered to the medical staff for the control group and the experimental group,respectively,to compare the incidence rates of DVT and other adverse reactions,QLI scores,Karnofsky Performance Scale scores,Mental Status Scale in Non-Psychiatric Settings scores,patient satisfaction,medical staff’s test marks,and satisfaction evaluation of the teaching model.RESULTS Compared with the control group,the experimental group exhibited significantly lower incidence rates of DVT and other adverse reactions and MSSNS scores but significantly higher QLI scores,KPS scores,patient satisfaction,medical staff’s test marks,and their satisfaction evaluations of the teaching model(P<0.05).CONCLUSION In a single-center practice,performing the multivariate integration teaching model for medical staff may effectively improve the patients’QLI and satisfaction and may have certain application value in preventing DVT in patients with gastric cancer and PICC. 展开更多
关键词 Multivariate integration teaching model Gastric cancer peripherally inserted central catheter intubation Deep vein thrombosis Quality of life SATISFACTION
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Diagnostic value evaluation of trefoil factors family 3 for the early detection of colorectal cancer 被引量:7
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作者 Hui Xie Jian-Hai Guo +5 位作者 Wei-Min An Sheng-Tao Tian Hai-Peng Yu Xue-Ling Yang Hua-Ming Wang Zhi Guo 《World Journal of Gastroenterology》 SCIE CAS 2017年第12期2159-2167,共9页
AIM The purpose of this study was to evaluate the diagnostic value of trefoil factor family 3(TFF3) for the early detection of colorectal cancer(CC). METHODS Serum TFF3 and carcino-embryonic antigen(CEA) were detected... AIM The purpose of this study was to evaluate the diagnostic value of trefoil factor family 3(TFF3) for the early detection of colorectal cancer(CC). METHODS Serum TFF3 and carcino-embryonic antigen(CEA) were detected in 527 individuals, including 115 healthy control(HC), 198 colorectal adenoma(CA), and 214 CC individuals in the training group. RESULTS Serum TFF3 showed no significant correlation with age, gender, or tumor location but showed significant correlation with the tumor stage. Serum TFF3 in the CC group was significantly higher than in the HC or CA group. The AUC values of TFF3 for discriminating between HC and CC and between CA and CC were 0.930(0.903, 0.958) and 0.834(0.796, 0.873). A multivariate model combining TFF3 and CEA was built. Compared to TFF3 or CEA alone, the multivariate model showed significant improvement(P < 0.001). For discriminating between HC and CC, HC and early stage CC, HC and advanced stage CC, CA and CC, CA and early stage CC, and CA and advanced stage CC in the training group, the sensitivities were 92.99%, 91.46%, 93.18%, 73.83%, 76.83%, and 81.82%, and the specificities were 91.30%, 91.30%, 93.91%, 88.38%, 77.27%, and 88.38%, respectively. After validation, the sensitivities were 89.39%, 85.71%, 90.79%, 72.73%, 71.43%, and 78.95%, and the specificities were 87.85%, 87.85%, 2.52%, 87.85%, 80.77%, and 87.50%, respectively. CONCLUSION The multivariate diagnostic model that included TFF3 and CEA showed significant improvement over the conventional biomarker CEA and might provide a potential method for the early detection of CC. 展开更多
关键词 Trefoil factor family 3 Colorectal cancer Colorectal adenoma Multivariate model Diagnostic value
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Multivariate predictive model for asymptomatic spontaneous bacterial peritonitis in patients with liver cirrhosis 被引量:10
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作者 Bo Tu Yue-Ning Zhang +6 位作者 Jing-Feng Bi Zhe Xu Peng Zhao Lei Shi Xin Zhang Guang Yang En-Qiang Qin 《World Journal of Gastroenterology》 SCIE CAS 2020年第29期4316-4326,共11页
BACKGROUNDSpontaneous bacterial peritonitis (SBP) is a detrimental infection of the asciticfluid in liver cirrhosis patients, with high mortality and morbidity. Earlydiagnosis and timely antibiotic administration have... BACKGROUNDSpontaneous bacterial peritonitis (SBP) is a detrimental infection of the asciticfluid in liver cirrhosis patients, with high mortality and morbidity. Earlydiagnosis and timely antibiotic administration have successfully decreased themortality rate to 20%-25%. However, many patients cannot be diagnosed in theearly stages due to the absence of classical SBP symptoms. Early diagnosis ofasymptomatic SBP remains a great challenge in the clinic.AIMTo establish a multivariate predictive model for early diagnosis of asymptomaticSBP using positive microbial cultures from liver cirrhosis patients with ascites.METHODSA total of 98 asymptomatic SBP patients and 98 ascites liver cirrhosis patients withnegative microbial cultures were included in the case and control groups,respectively. Multiple linear stepwise regression analysis was performed toidentify potential indicators for asymptomatic SBP diagnosis. The diagnosticperformance of the model was estimated using the receiver operatingcharacteristic curve.RESULTSPatients in the case group were more likely to have advanced disease stages,cirrhosis related-complications, worsened hematology and ascites, and higher mortality. Based on multivariate analysis, the predictive model was as follows: y (P) = 0.018 + 0.312 × MELD (model of end-stage liver disease) + 0.263 × PMN(ascites polymorphonuclear) + 0.184 × N (blood neutrophil percentage) + 0.233 ×HCC (hepatocellular carcinoma) + 0.189 × renal dysfunction. The area under thecurve value of the established model was 0.872, revealing its high diagnosticpotential. The diagnostic sensitivity was 73.5% (72/98), the specificity was 86.7%(85/98), and the diagnostic efficacy was 80.1%.CONCLUSIONOur predictive model is based on the MELD score, polymorphonuclear cells,blood N, hepatocellular carcinoma, and renal dysfunction. This model mayimprove the early diagnosis of asymptomatic SBP. 展开更多
关键词 Spontaneous bacterial peritonitis ASYMPTOMATIC ASCITES Multivariate predictive model Liver cirrhosis
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Studies on Heavy Metal Pollution in Soil-Plant System:A Review 被引量:9
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作者 Wang Haiyan Sun XiangyangCollege of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P.R. China 《Forestry Studies in China》 CAS 2003年第1期55-62,共8页
Heavy metal pollution in soil-plant system is of major environmental concern on a world scale and in China in particular with the rapid development of industry. The heavy metal pollution status in soil-plant system in... Heavy metal pollution in soil-plant system is of major environmental concern on a world scale and in China in particular with the rapid development of industry. The heavy metal pollution status in soil-plant system in China, the research progress on the bioavailability of heavy metals (affecting factors, extraction methods, free-ion activity model, adsorption model, multivariate regression model, Q-I relationship, and compound pollution), and soil remediation are reviewed in the paper. Future research and monitoring is also discussed. 展开更多
关键词 heavy metal pollution soil-plant system BIOAVAILABILITY free-ion activity model adsorption model multivariate regression model compound pollution soil remediation
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Artificial neural network models predicting the leaf area index:a case study in pure even-aged Crimean pine forests from Turkey 被引量:4
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作者 ilker Ercanli Alkan Gunlu +1 位作者 Muammer Senyurt Sedat Keles 《Forest Ecosystems》 SCIE CSCD 2018年第4期400-411,共12页
Background: Leaf Area Index(LAI) is an important parameter used in monitoring and modeling of forest ecosystems. The aim of this study was to evaluate performance of the artificial neural network(ANN) models to predic... Background: Leaf Area Index(LAI) is an important parameter used in monitoring and modeling of forest ecosystems. The aim of this study was to evaluate performance of the artificial neural network(ANN) models to predict the LAI by comparing the regression analysis models as the classical method in these pure and even-aged Crimean pine forest stands.Methods: One hundred eight temporary sample plots were collected from Crimean pine forest stands to estimate stand parameters. Each sample plot was imaged with hemispherical photographs to detect the LAI. The partial correlation analysis was used to assess the relationships between the stand LAI values and stand parameters, and the multivariate linear regression analysis was used to predict the LAI from stand parameters. Different artificial neural network models comprising different number of neuron and transfer functions were trained and used to predict the LAI of forest stands.Results: The correlation coefficients between LAI and stand parameters(stand number of trees, basal area, the quadratic mean diameter, stand density and stand age) were significant at the level of 0.01. The stand age, number of trees, site index, and basal area were independent parameters in the most successful regression model predicted LAI values using stand parameters(R_(adj)~2=0.5431). As corresponding method to predict the interactions between the stand LAI values and stand parameters, the neural network architecture based on the RBF 4-19-1 with Gaussian activation function in hidden layer and the identity activation function in output layer performed better in predicting LAI(SSE(12.1040), MSE(0.1223), RMSE(0.3497), AIC(0.1040), BIC(-77.7310) and R^2(0.6392)) compared to the other studied techniques.Conclusion: The ANN outperformed the multivariate regression techniques in predicting LAI from stand parameters. The ANN models, developed in this study, may aid in making forest management planning in study forest stands. 展开更多
关键词 Leaf area index Multivariate linear regression model Artificial neural network modeling Crimean pine Stand parameters
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Transcriptomic analysis reveals key lnc RNAs associated with ribosomal biogenesis and epidermis differentiation in head and neck squamous cell carcinoma 被引量:3
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作者 Yu-zhu GUO Hui-hui SUN +1 位作者 Xiang-ting WANG Mei-ting WANG 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2018年第9期674-688,共15页
Objective: In this study, we aimed to expand current knowledge of head and neck squamous cell carcinoma (HNSCC)-associated long noncoding RNAs (IncRNAs), and to discover potential IncRNA prognostic biomarkers for... Objective: In this study, we aimed to expand current knowledge of head and neck squamous cell carcinoma (HNSCC)-associated long noncoding RNAs (IncRNAs), and to discover potential IncRNA prognostic biomarkers for HNSCC based on next-generation RNA-seq. Methods: RNA-seq data of 546 samples from patients with HNSCC were downloaded from The Cancer Genome Atlas (TCGA), including 43 paired samples of tumor tissue and adjacent normal tissue. An integrated analysis incorporating differential expression, weighted gene co-expression networks, functional enrichment, clinical parameters, and survival analysis was conducted to discover HNSCC-associated IncRNAs. The function of CYTOR was verified by cell-based experiments. To further identify IncRNAs with prognostic significance, a multivariate Cox proportional hazard regression analysis was performed. The identified IncRNAs were validated with an independent cohort using clinical feature relevance analysis and multivariate Cox regression analysis. Results: We identified nine HNSCC-relevant IncRNAs likely to play pivotal roles in HNSCC onset and development. By functional enrichment analysis, we revealed that CYTOR might participate in the multistep pathological processes of cancer, such as ribosome biogenesis and maintenance of genomic stability. CY-I-OR was identified to be positively correlated with lymph node metastasis, and significantly negatively correlated with overall survival (OS) and disease free survival (DFS) of HNSCC patients. Moreover, CYTOR inhibited cell apoptosis following treatment with the chemotherapeutic drug diamminedichloroplatinum (DDP). HCG22, the most dramatically down-regulated IncRNA in tumor tissue, may function in epidermis differentiation. It was also significantly associated with several clinical features of patients with HNSCC, and positively correlated with patient survival. CYTOR and HCG22 maintained their prognostic values in- dependent of several clinical features in multivariate Cox hazards analysis. Notably, validation either based on an independent HNSCC cohort or by laboratory experiments confirmed these findings. Conclusions: Our transcriptomic analysis suggested that dysregulation of these HNSCC-associated IncRNAs might be involved in HNSCC oncogenesis and progression. Moreover, CYTOR and HCG22 were confirmed as two independent prognostic factors for HNSCC patient survival, providing new insights into the roles of these IncRNAs in HNSCC as well as clinical applications. 展开更多
关键词 Head and neck squamous cell carcinoma Long noncoding RNA (IncRNA) Weighted gene co-expressionnetwork analysis (WGCNA) Clinicopathological feature Multivariate Cox regression model
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Improving reservoir volumetric estimations in petroleum resource assessment using discovery process models 被引量:2
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作者 Osadetz Kirk G. 《Petroleum Science》 SCIE CAS CSCD 2009年第2期105-118,共14页
The reservoir volumetric approach represents a widely accepted, but flawed method of petroleum play resource calculation. In this paper, we propose a combination of techniques that can improve the applicability and qu... The reservoir volumetric approach represents a widely accepted, but flawed method of petroleum play resource calculation. In this paper, we propose a combination of techniques that can improve the applicability and quality of the resource estimation. These techniques include: 1) the use of the Multivariate Discovery Process model (MDP) to derive unbiased distribution parameters of reservoir volumetric variables and to reveal correlations among the variables; 2) the use of the Geo-anchored method to estimate simultaneously the number of oil and gas pools in the same play; and 3) the crossvalidation of assessment results from different methods. These techniques are illustrated by using an example of crude oil and natural gas resource assessment of the Sverdrup Basin, Canadian Archipelago. The example shows that when direct volumetric measurements of the untested prospects are not available, the MDP model can help derive unbiased estimates of the distribution parameters by using information from the discovered oil and gas accumulations. It also shows that an estimation of the number of oil and gas accumulations and associated size ranges from a discovery process model can provide an alternative and efficient approach when inadequate geological data hinder the estimation. Cross-examination of assessment results derived using different methods allows one to focus on and analyze the causes for the major differences, thus providing a more reliable assessment outcome. 展开更多
关键词 Multivariate Discovery Process model sampling bias correction cross-validation Geoanchored method
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Formidable females redux:male social integration into female networks and the value of dynamic multilayer networks 被引量:1
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作者 Tyler R.BONNELL ChloéVILETTE +2 位作者 Christopher YOUNG Stephanus Peter HENZI ouise BARRETT 《Current Zoology》 SCIE CAS CSCD 2021年第1期49-57,共9页
The development of multilayer network techniques is a boon for researchers who wish to understand how different interaction layers might influence each other,and how these in turn might influence group dynamics.Here,w... The development of multilayer network techniques is a boon for researchers who wish to understand how different interaction layers might influence each other,and how these in turn might influence group dynamics.Here,we investigate how integration between male and female grooming and aggression interaction networks influences male power trajectories in vervet monkeys Chlorocebus pygerythrus.Our previous analyses of this phenomenon used a monolayer approach,and our aim here is to extend these analyses using a dynamic multilayer approach.To do so,we constructed a temporal series of male and female interaction layers.We then used a multivariate multilevel autoregression model to compare cross-lagged associations between a male's centrality in the female grooming layer and changes in male Elo ratings.Our results confirmed our original findings:changes in male centrality within the female grooming network were weakly but positively tied to changes in their Elo ratings.However,the multilayer network approach offered additional insights into this social process,identifying how changes in a male's centrality cascade through the other network layers.This dynamic view indicates that the changes in Elo ratings are likely to be short-lived,but that male centrality within the female network had a much stronger impact throughout the multilayer network as a whole,especially on reducing intermale aggression(i.e.,aggression directed by males toward other males).We suggest that multilayer social network approaches can take advantage of increased amounts of social data that are more commonly collected these days,using a variety of methods.Such data are inherently multilevel and multilayered,and thus offer the ability to quantify more precisely the dynamics of animal social behaviors. 展开更多
关键词 multilayer networks multilevel multivariate autoregressive model primate social dynamics social networks SOCIALITY time-aggregated networks vervet monkeys
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Some Asymptotic Properties for Multivariate Partially Linear Models 被引量:2
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作者 ZHOU Xing-cai HU Shu-he 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期270-274,共5页
The paper considers a multivariate partially linear model under independent errors,and investigates the asymptotic bias and variance-covariance for parametric component βand nonparametric component F(·)by the ... The paper considers a multivariate partially linear model under independent errors,and investigates the asymptotic bias and variance-covariance for parametric component βand nonparametric component F(·)by the GJS estimator and Kernel estimation. 展开更多
关键词 multivariate partially linear models GJS estimator asymptotic properties
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N4SID and MOESP Algorithms to Highlight the Ill-conditioning into Subspace Identification 被引量:4
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作者 Slim Hachicha Maher Kharrat Abdessattar Chaari 《International Journal of Automation and computing》 EI CSCD 2014年第1期30-38,共9页
In this paper,an analysis for ill conditioning problem in subspace identifcation method is provided.The subspace identifcation technique presents a satisfactory robustness in the parameter estimation of process model ... In this paper,an analysis for ill conditioning problem in subspace identifcation method is provided.The subspace identifcation technique presents a satisfactory robustness in the parameter estimation of process model which performs control.As a frst step,the main geometric and mathematical tools used in subspace identifcation are briefly presented.In the second step,the problem of analyzing ill-conditioning matrices in the subspace identifcation method is considered.To illustrate this situation,a simulation study of an example is introduced to show the ill-conditioning in subspace identifcation.Algorithms numerical subspace state space system identifcation(N4SID)and multivariable output error state space model identifcation(MOESP)are considered to study,the parameters estimation while using the induction motor model,in simulation(Matlab environment).Finally,we show the inadequacy of the oblique projection and validate the efectiveness of the orthogonal projection approach which is needed in ill-conditioning;a real application dealing with induction motor parameters estimation has been experimented.The obtained results proved that the algorithm based on orthogonal projection MOESP,overcomes the situation of ill-conditioning in the Hankel s block,and thereby improving the estimation of parameters. 展开更多
关键词 Subspace identification ILL-CONDITIONING oblique projection orthogonal projection algorithms numerical subspace state space system identification (N4SID) multivariable output error state space model identification (MOESP) induction motor
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All Admissible Linear Estimators under Quadratic Loss in Multivariate Model 被引量:1
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作者 邓起荣 陈建宝 《Northeastern Mathematical Journal》 CSCD 2000年第1期1-9,共9页
For multivariate linear model Y=XΘ+ε, ~N(0, σ 2ΣV), this paper is concerned with the admissibility of linear estimators of estimable function SXΘ in the class of all estimators. All admissible linear estimators ... For multivariate linear model Y=XΘ+ε, ~N(0, σ 2ΣV), this paper is concerned with the admissibility of linear estimators of estimable function SXΘ in the class of all estimators. All admissible linear estimators of SXΘ are given under each of four definitions of admissibility. 展开更多
关键词 multivariate linear model quadratic loss admissible estimator
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Prediction of wetting pattern dimensions under moistube irrigation with a multivariate nonlinear model 被引量:1
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作者 Yan-wei Fan Chong Ren +2 位作者 Zhi-wei Yang Chang-yan Zhang Wei-fan Yin 《Water Science and Engineering》 CSCD 2024年第3期217-225,共9页
Moistube irrigation is a new micro-irrigation technology.Accurately estimating its wetting pattern dimensions presents a challenge.Therefore,it is necessary to develop models for efficient assessment of the wetting tr... Moistube irrigation is a new micro-irrigation technology.Accurately estimating its wetting pattern dimensions presents a challenge.Therefore,it is necessary to develop models for efficient assessment of the wetting transport pattern in order to design a cost-effective moistube irrigation system.To achieve this goal,this study developed a multivariate nonlinear regression model and compared it with a dimensional model.HYDRUS-2D was used to perform numerical simulations of 56 irrigation scenarios with different factors.The experiments showed that the shape of the wetting soil body approximated a cylinder and was mainly affected by soil texture,pressure head,and matric potential.A multivariate nonlinear model using a power function relationship between wetting size and irrigation time was developed,with a determination coefficient greater than 0.99.The model was validated for cases with six soil texture types,with mean average absolute errors of 0.43-0.90 cm,root mean square errors of 0.51-0.95 cm,and mean deviation percentage values of 3.23%-6.27%.The multivariate nonlinear regression model outperformed the dimensional model.It can therefore provide a scientific foundation for the development of moistube irrigation systems. 展开更多
关键词 Moistube irrigation Wetting pattern dimensions Multivariate nonlinear regression model Dimensional model HYDRUS-2D
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