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A comparative study of seismic tomography models of Southwest China 被引量:1
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作者 Xuezhen Zhang Xiaodong Song Feiyi Wang 《Earthquake Science》 2023年第1期15-39,共25页
The margin of the Tibetan Plateau of Southwest China is one of the most seismically active regions of China and is the location of the China Seismic Experimental Site(CSES).Many studies have developed seismic velocity... The margin of the Tibetan Plateau of Southwest China is one of the most seismically active regions of China and is the location of the China Seismic Experimental Site(CSES).Many studies have developed seismic velocity models of Southwest China,but few have compared and evaluated these models which is important for further model improvement.Thus,we compared six published seismic shear-wave velocity models of Southwest China on absolute velocity and velocity perturbation patterns.The models are derived from different types of data(e.g.,surface waves from ambient noise and earthquakes,body-wave travel times,receiver functions) and inversion methods.We interpolated the models into a uniform horizontal grid(0.5° × 0.5°) and vertically sampled them at 5,10,20,30,40,and 60 km depths.We found significant differences between the six models.Then,we selected three of them that showed greater consistency for further comparison.Our further comparisons revealed systematic biases between models in absolute velocity that may be related to different data types.The perturbation pattern of the model is especially divergent in the shallow part,but more consistent in the deep part.We conducted synthetic and inversion tests to explore possible causes and our results imply that systematic differences between the data,differences in methods,and other factors may directly affect the model.Therefore,the Southwest China velocity model still has considerable room for improvement,and the impact of inconsistency between different data types on the model needs further research.Finally,we proposed a new reference shear-wave velocity model of Southwest China(SwCM-S1.0) based on the three selected models with high consistency.We believe that this model is a better representation of more robust features of the models that are based on different data sets. 展开更多
关键词 model comparison shear-wave velocity model Southwest China
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Comparison on Winter Wheat Yield Estimating Models Based on Radarsat-2 and HJ Satellite in Huaihe River Region 被引量:1
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作者 范伟 陈磊 +2 位作者 陈娟 闫洪凯 刘韬 《Agricultural Science & Technology》 CAS 2016年第4期1019-1023,共5页
The establishment of crop yield estimating model based on microwave and optical satellite images can conduct the mutual verification of the accuracy of the reported crop yield and the precision of the estimating model... The establishment of crop yield estimating model based on microwave and optical satellite images can conduct the mutual verification of the accuracy of the reported crop yield and the precision of the estimating model. With Shou County and Huaiyuan County of Anhui Province as the experimental fields of winter wheat producing areas, the linear winter wheat yield estimating models were established by adopting backscattering coefficient and Normalized Difference Vegetation Index(NDVI) based on images from the synthetic aperture radar(SAR)—RDARSAT-2 and HJ satellite photographed in mid-April and early May, 2014, and then comparisons were conducted on the accuracy of the yield estimating models. The accuracies of the yield estimating models established using co-polarized(HH) and cross-polarized(HV) modes of SAR in Jiangou Town, Shou County were 68.37% and 74.01%, respectively, while the accuracies in Longkang Town, Huaiyuan County were 63.10%and 69.10%, respectively. Accuracies of yield estimating models established by HJ satellite data were 69.52% and 66.43% in Shou County and Huaiyuan County, respectively. Accuracies of winter yield estimating model based on HJ satellite data and that based on SAR were closed, and the yield difference of winter wheat in the lodging region was analyzed in detail. The model results laid the foundation and accumulated experience for the verification, parameters correction and promotion of the winter wheat yield estimating model. 展开更多
关键词 Winter wheat yield estimating model Synthetic aperture radar RADARSAT-2 HJ satellite model comparison
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Accuracy comparison of dry matter intake prediction models evaluated by a feeding trial of lactating dairy cows fed two total mixed rations with different forage source 被引量:4
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作者 PAN Xiao-hua YANG Liang +2 位作者 Yves Beckers XIONG Ben-hai JIANG Lin-shu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第4期921-929,共9页
Dry matter intake (DMI) prediction models of NRC (2001), Fox et aL (2004) and Fuentes-Pila et aL (2003) were targeted in the present study, and the objective was to evaluate their prediction accuracy with feed... Dry matter intake (DMI) prediction models of NRC (2001), Fox et aL (2004) and Fuentes-Pila et aL (2003) were targeted in the present study, and the objective was to evaluate their prediction accuracy with feeding trial data of 32 lactating Holstein cows fed two total mixed rations with different forage source. Thirty-two cows were randomly assigned to one of two total mixed ration groups: a ration containing a mixed forage (MF) of 3.7% Chinese wildrye, 28.4% alfalfa hay and 26.5% corn silage diet and another ration containing 33.8% corn stover (CS) as unique forage source. The actual DMI was greater in MF group than in CS group (P=0.064). The NRC model to predict DMI resulted in the lowest root mean square prediction error for both MF and CS groups (1.09 kg d-1 vs. 1.28 kg d-1) and the highest accuracy and precision based on concordance correlation coefficient for both MF and CS diet (0.89 vs. 0.87). Except the NRC model, the other two models presented mean and linear biases in both MF and CS diets when prediction residuals were plotted against predicted DMI values (P〈0.001). The DMI variation in MF was caused by week of lactation (55.6%), milk yield (13.9%), milk fat percentage (7.1%) and dietary neutral detergent fiber (13.3%), while the variation in CS was caused by week of lactation (50.9%), live body weight (28.2%), milk yield (8.4%), milk fat percentage (5.2%) and dietary neutral detergent fibre (3.8%). In a brief, the NRC model to predict DMI is comparatively acceptable for lactating dairy cows fed two total mixed rations with different forage source. 展开更多
关键词 dairy cows dry matter intake model comparison mixed forage corn stover
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Numerical model for homogeneous cohesive dam breaching due to overtopping failure 被引量:5
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作者 ZHONG Qi-ming CHEN Sheng-shui DENG Zhao 《Journal of Mountain Science》 SCIE CSCD 2017年第3期571-580,共10页
Based on the large-scale model tests, a simplified dam breach model for homogeneous cohesive dam due to overtopping failure is put forward. The model considers headcut erosion as one of the key homogeneous cohesive da... Based on the large-scale model tests, a simplified dam breach model for homogeneous cohesive dam due to overtopping failure is put forward. The model considers headcut erosion as one of the key homogeneous cohesive dam breaching mechanisms and we calculate the time-averaged headcut migration rate using an energy-based empirical formula. A numerical method is adopted to determine the initial scour position at the downstream slope in terms of the water head and dam height, and the broad-crested weir equation is utilized to simulate the breach flow. The limit equilibrium method is used to analyze the stability of breach slope during the breach process. An iterative method is developed to simulate the coupling process of soil and water at each time step. The calculated results of three dam breach cases testify the reasonability of the model, and the sensitivity studies of soil erodibility show that sensitivity is dependent on each test case's soil conditions. In addition, three typical dam breach models, NWS BREACH, WinDAM B, and HR BREACH, are also chosen to compare with the proposed model. It is found that NWS BREACH may have large errors for cohesive dams, since it uses a noncohesive sediment transport model and does notconsider headcut erosion, WinDAM B and HR BREACH consider headcut erosion as the breaching mechanism and handle well homogeneous cohesive dam overtopping failure, but overall, the proposed model has the best performance. 展开更多
关键词 KeHomogeneous cohesive dam OVERTOPPING Headcut Initial scour position Sensitivity analysis models comparison
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A comparative study of seismic tomography models of the Chinese continental lithosphere 被引量:5
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作者 Xuezhen Zhang Xiaodong Song Jiangtao Li 《Earthquake Science》 2022年第3期161-185,共25页
The Chinese mainland is subject to complicated plate interactions that give rise to its complex structure and tectonics. While several seismic velocity models have been developed for the Chinese mainland, apparent dis... The Chinese mainland is subject to complicated plate interactions that give rise to its complex structure and tectonics. While several seismic velocity models have been developed for the Chinese mainland, apparent discrepancies exist and, so far, little effort has been made to evaluate their reliability and consistency. Such evaluations are important not only for the application and interpretation of model results but also for future model improvement. To address this problem, here we compare five published shear-wave velocity models with a focus on model consistency. The five models were derived from different datasets and methods (i.e., body waves, surface waves from earthquakes, surface waves from noise interferometry, and full waves) and interpolated into uniform horizontal grids (0.5° × 0.5°) with vertical sampling points at 5 km, 10 km, and then 20 km intervals to a depth of 160 km below the surface, from which we constructed an averaged model (AM) as a common reference for comparative study. We compare both the absolute velocity values and perturbation patterns of these models. Our comparisons show that the models have large (> 4%) differences in absolute values, and these differences are independent of data coverage and model resolution. The perturbation patterns of the models also show large differences, although some of the models show a high degree of consistency within certain depth ranges. The observed inconsistencies may reflect limited model resolution but, more importantly, systematic differences in the datasets and methods employed. Thus, despite several seismic models being published for this region, there is significant room for improvement. In particular, the inconsistencies in both data and methodologies need to be resolved in future research. Finally, we constructed a merged model (ChinaM-S1.0) that incorporates the more robust features of the five published models. As the existing models are constrained by different datasets and methods, the merged model serves as a new type of reference model that incorporates the common features from the joint datasets and methods for the shear-wave velocity structure of the Chinese mainland lithosphere. 展开更多
关键词 Chinese mainland shear-wave velocity model model comparison continental lithosphere
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Comparison of three mathematical prediction models in patients with a solitary pulmonary nodule 被引量:9
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作者 Xuan Zhang Hong-Hong Yan +4 位作者 Jun-Tao Lin Ze-Hua Wu Jia Liu Xu-Wei Cao Xue-Ning Yang 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2014年第6期647-652,共6页
Background: Effective methods for managing patients with solitary pulmonary nodules(SPNs) depend critically on the predictive probability of malignancy.Methods: Between July 2009 and June 2011, data on gender, age... Background: Effective methods for managing patients with solitary pulmonary nodules(SPNs) depend critically on the predictive probability of malignancy.Methods: Between July 2009 and June 2011, data on gender, age, cancer history, tumor familial history, smoking status, tumor location, nodule size, spiculation, calcification, the tumor border, and the final pathological diagnosis were collected retrospectively from 154 surgical patients with an SPN measuring 3-30 mm. Each final diagnosis was compared with the probability calculated by three predicted models—the Mayo, VA, and Peking University(PU) models. The accuracy of each model was assessed using area under the receiver operating characteristics(ROC) and calibration curves.Results: The area under the ROC curve of the PU model [0.800; 95% confidence interval(CI): 0.708-0.891] was higher than that of the Mayo model(0.753; 95% CI: 0.650-0.857) or VA model(0.728; 95% CI: 0.623-0.833); however, this finding was not statistically significant. To varying degrees, calibration curves showed that all three models overestimated malignancy.Conclusions: The three predicted models have similar accuracy for prediction of SPN malignancy, although the accuracy is not sufficient. For Chinese patients, the PU model may has greater predictive power.Background: Here, we introduced our short experience on the application of a new CUSA Excel ultrasonic aspiration system, which was provided by Integra Lifesciences corporation, in skull base meningiomas resection.Methods: Ten patients with anterior, middle skull base and sphenoid ridge meningioma were operated using the CUSA Excel ultrasonic aspiration system at the Neurosurgery Department of Shanghai Huashan Hospital from August 2014 to October 2014. There were six male and four female patients, aged from 38 to 61 years old(the mean age was 48.5 years old). Five cases with tumor located at anterior skull base, three cases with tumor on middle skull base, and two cases with tumor on sphenoid ridge.Results: All the patents received total resection of meningiomas with the help of this new tool, and the critical brain vessels and nerves were preserved during operations. All the patients recovered well after operation.Conclusions: This new CUSA Excel ultrasonic aspiration system has the advantage of preserving vital brain arteries and cranial nerves during skull base meningioma resection, which is very important for skull base tumor operations. This key step would ensure a well prognosis for patients. We hope the neurosurgeons would benefit from this kind of technique.Background: The purposes of this study were to explore the effects of high mobility group protein box 1(HMGB1) gene on the growth, proliferation, apoptosis, invasion, and metastasis of glioma cells, with an attempt to provide potential therapeutic targets for the treatment of glioma. Methods: The expressions of HMGB1 in glioma cells(U251, U-87 MG and LN-18) and one control cell line(SVG p12) were detected by real time PCR and Western blotting, respectively. Then, the effects of HMGB1 on the biological behaviors of glioma cells were detected: the expression of HMGB1 in human glioma cell lines U251 and U-87 MG were suppressed using RNAi technique, then the influences of HMGB1 on the viability, cycle, apoptosis, and invasion abilities of U251 and U-87 MG cells were analyzed using in a Transwell invasion chamber. Also, the effects of HMGB1 on the expressions of cyclin D1, Bax, Bcl-2, and MMP 9 were detected. Results: As shown by real-time PCR and Western blotting, the expression of HMGB1 significantly increased in glioma cells(U251, U-87 MG, and LN-18) in comparison with the control cell line(SVG p12); the vitality, proliferation and invasive capabilities of U251 and U-87 MG cells in the HMGB1 siR NA-transfected group were significantly lower than those in the blank control group and negative control(NC) siR NA group(P〈0.05) but showed no significant difference between the blank control group and NC siR NA group. The percentage of apoptotic U251 and U-87 MG cells was significantly higher in the HMGB1 siR NA-transfected group than in the blank control group and NC siR NA group(P〈0.05) but was similar between the latter two groups. The HMGB1 siR NA-transfected group had significantly lower expression levels of Cyclin D1, Bcl-2, and MMP-9 protein in U251 and U-87 MG cells and significantly higher expression of Bax protein than in the blank control group and NC siR NA group(P〈0.05); the expression profiles of cyclin D1, Bax, Bcl-2, and MMP 9 showed no significant change in both blank control group and NC siR NA group. Conclusions: HMGB1 gene may promote the proliferation and migration of glioma cells and suppress its effects of apoptosis. Inhibition of the expression of HMGB1 gene can suppress the proliferation and migration of glioma cells and promote their apoptosis. Our observations provided a new target for intervention and treatment of glioma. 展开更多
关键词 Solitary pulmonary nodule(SPN) benign and malignant model comparison
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Comparison of Ten Potential Evapotranspiration Models and Their Attribution Analyses for Ten Chinese Drainage Basins 被引量:2
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作者 Ruiheng XIE Aihui WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2020年第9期959-974,共16页
Potential evapotranspiration(EPET)is usually calculated by empirical methods from surface meteorological variables,such as temperature,radiation and wind speed.The in-situ measured pan evaporation(ETpan)can also be us... Potential evapotranspiration(EPET)is usually calculated by empirical methods from surface meteorological variables,such as temperature,radiation and wind speed.The in-situ measured pan evaporation(ETpan)can also be used as a proxy for EPET.In this study,EPET values computed from ten models are compared with observed ETpan data in ten Chinese river basins for the period 1961−2013.The daily observed meteorological variables at 2267 stations are used as the input to those models,and a ranking scheme is applied to rank the statistical quantities(ratio of standard deviations,correlation coefficient,and ratio of trends)between ETpan and modeled EPET in different river basins.There are large deviations between the modeled EPET and the ETpan in both the magnitude and the annual trend at most stations.In eight of the basins(except for Southeast and Southwest China),ETpan shows decreasing trends with magnitudes ranging between−0.01 mm d−1 yr−1 and−0.03 mm d−1 yr−1,while the decreasing trends in modeled EPET are less than−0.01 mm d−1 yr−1.Inter comparisons among different models in different river basins suggest that PETHam1 is the best model in the Pearl River basin,PETHam2 outperforms other models in the Huaihe River,Yangtze River and Yellow River basins,and PETFAO is the best model for the remaining basins.Sensitivity analyses reveal that wind speed and sunshine duration are two important factors for decreasing EPET in most basins except in Southeast and Southwest China.The increasing EPET trend in Southeast China is mainly attributed to the reduced relative humidity. 展开更多
关键词 potential evapotranspiration model pan evaporation model comparison sensitivity analysis China
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Analysis of the Resolution of Crime Using Predictive Modeling 被引量:1
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作者 Keshab R. Dahal Jiba N. Dahal +1 位作者 Kenneth R. Goward Oluremi Abayami 《Open Journal of Statistics》 2020年第3期600-610,共11页
There has been evidence of crime in the US since colonization. In this article, we analyze the crime statistics of San Francisco and its resolution of crime recorded from January to September of the year 2018. We defi... There has been evidence of crime in the US since colonization. In this article, we analyze the crime statistics of San Francisco and its resolution of crime recorded from January to September of the year 2018. We define resolution of crime as a target variable and study its relationship with other variables. We make several classification models to predict resolution of crime using several data mining techniques and suggest the best model for predicting resolution. 展开更多
关键词 Machine Learning Classification model Comparison Predictive modeling Resolution of Crime
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A Model Comparison Study of Fragment Production in 140 A MeV 58,64Ni+9Be Reactions
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作者 马春旺 张艳丽 +1 位作者 王闪闪 乔春源 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期29-33,共5页
The cross sections of fragments produced in the 140 A MeV58,64Ni+9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics (AMD) model, the modified statistical abrasion... The cross sections of fragments produced in the 140 A MeV58,64Ni+9 Be projectile fragmentation reactions are calculated by using the antisymmetrized molecular dynamics (AMD) model, the modified statistical abrasion- ablation (SAA) model, and the empirical EPAX2/EPAX3 formulae. The Gogny-gO interaction is taken as the effective nucleon-nucleon interaction in the AMD calculation, and the decays of fragments obtained from the AMD results are calculated by using the GEMINI code. The calculated cross sections of fragments are compared. 展开更多
关键词 BE A model Comparison Study of Fragment Production in 140 A MeV REACTIONS AMD NI
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Comparison of coupled and uncoupled models in simulating Monsoon Intraseasonal Oscillation from CMIP6
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作者 Baosheng Li Dake Chen +1 位作者 Tao Lian Jianhuang Qin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第10期100-108,共9页
The monsoon intraseasonal oscillation(MISO)is the dominant variability over the Indian Ocean during the Indian summer monsoon(ISM)season and is characterized by pronounced northward propagation.Previous studies have s... The monsoon intraseasonal oscillation(MISO)is the dominant variability over the Indian Ocean during the Indian summer monsoon(ISM)season and is characterized by pronounced northward propagation.Previous studies have shown that general circulation models(GCMs)still have difficulty in simulating the northwardpropagating MISO,and that the role of air-sea interaction in MISO is unclear.In this study,14 atmosphere-ocean coupled GCMs(CGCMs)and the corresponding atmosphere-only GCMs(AGCMs)are selected from Phase 6 of the Coupled Model Intercomparison Project(CMIP6)to assess their performance in reproducing MISO and the associated vortex tilting mechanism.The results show that both CGCMs and AGCMs are able to well simulate the significant relationship between MISO and vortex tilting.However,80%of CGCMs show better simulation skills for MISO than AGCMs in CMIP6.In AGCMs,the poor model fidelity in MISO is due to the failure simulation of vortex tilting.Moreover,it is found that failure to simulate the downward motion to the north of convection is responsible for the poor simulation of vortex tilting in AGCMs.In addition,it is observed that there is a significant relationship between the simulated sea surface temperature gradient and simulated vertical velocity shear in the meridional direction.These findings indicate that air-sea interaction may play a vital role in simulating vertical motions in tilting and MISO processes.This work offers us a specific target to improve the MISO simulation and further studies are needed to elucidate the physical processes of this air-sea interaction coupling with vortex tilting. 展开更多
关键词 monsoon intraseasonal oscillation(MISO) model comparison vortex tilting CMIP6
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Software Testing Method Based on Model Comparison
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作者 谢晓东 卢炎生 毛澄印 《Journal of Southwest Jiaotong University(English Edition)》 2008年第2期99-108,共10页
A model comparison based software testing method (MCST) is proposed. In this method, the requirements aria programs or software under test are transformed into the ones in the same form, and described by the same mo... A model comparison based software testing method (MCST) is proposed. In this method, the requirements aria programs or software under test are transformed into the ones in the same form, and described by the same model describe language (MDL). Then, the requirements are transformed into a specification model and the programs into an implementation model. Thus, the elements and structures of the two models are compared, and the differences between them are obtained. Based on the diffrences, a test suite is generated. Different MDLs can be chosen for the software under test. The usages of two classical MDLs in MCST, the equivalence classes model and the extended finite state machine (EFSM) model, are described with example applications. The results show that the test suites generated by MCST are more efficient and smaller than some other testing methods, such as the pathcoverage testing method, the object state diagram testing method, etc. 展开更多
关键词 Software testing Test suite generation model comparison
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Classification of Acupuncture Points Based on the Bert Model*
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作者 Xi Zhong Yangli Jia +1 位作者 Dekui Li Xiangliang Zhang 《Journal of Data Analysis and Information Processing》 2021年第3期123-135,共13页
In this paper, we explore the multi-classification problem of acupuncture acupoints bas</span><span><span style="font-family:Verdana;">ed on </span><span style="font-family:Ve... In this paper, we explore the multi-classification problem of acupuncture acupoints bas</span><span><span style="font-family:Verdana;">ed on </span><span style="font-family:Verdana;">Bert</span><span style="font-family:Verdana;"> model, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;">, we try to recommend the best main acupuncture point for treating the disease by classifying and predicting the main acupuncture point for the disease, and further explore its acupuncture point grouping to provide the medical practitioner with the optimal solution for treating the disease and improv</span></span></span><span style="font-family:Verdana;">ing</span><span style="font-family:""><span style="font-family:Verdana;"> the clinical decision-making ability. The Bert-Chinese-Acupoint model was constructed by retraining </span><span style="font-family:Verdana;">on the basis of</span><span style="font-family:Verdana;"> the Bert model, and the semantic features in terms of acupuncture points were added to the acupunctu</span></span><span style="font-family:""><span style="font-family:Verdana;">re point corpus in the fine-tuning process to increase the semantic features in terms of acupuncture </span><span style="font-family:Verdana;">points,</span><span style="font-family:Verdana;"> and compared with the machine learning method. The results show that the Bert-Chinese Acupoint model proposed in this paper has a 3% improvement in accuracy compared to the </span><span style="font-family:Verdana;">best performing</span><span style="font-family:Verdana;"> model in the machine learning approach. 展开更多
关键词 Bert model Machine Learning Classification model Comparison
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Applicability of Waterside Corrosion Models in Range of IFPE Database
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作者 Jun Wang Tong Liu Yuemin Zhou 《Journal of Energy and Power Engineering》 2014年第2期318-325,共8页
Fuel rod cladding waterside corrosion is one of the phenomena that limit the life time of nuclear fuel. Corrosion performance depends on the cladding material properties as well as operating conditions during the irra... Fuel rod cladding waterside corrosion is one of the phenomena that limit the life time of nuclear fuel. Corrosion performance depends on the cladding material properties as well as operating conditions during the irradiation of the fuel. As a function of temperature, power history, water chemistry, time, etc., waterside corrosion is of great concern in fuel performance evaluation, especially for high burnup fuels. This paper is dedicated to the study of the waterside corrosion phenomenon using the IFPE database by COPERNIC, which is developed for the analysis of fuel rod behaviors in normal operation and transient conditions. Different models, MATPRO, FRAMATOME and EPRI models, for example, are adopted in the simulations. The results derived from the models are compared and the unconformities are analyzed. Based on the comparative analysis, reasonable models are chosen to simulate certain irradiated fuel rods. Our analyses indicate that potential affecting factors which are not considered in COPERNIC code, such as water chemistry and alloy composition, should be responsible for discrepancies of certain rod predictions. 展开更多
关键词 Waterside corrosion model comparison influencing factors IFPE database.
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A New Activity-Based Cost (ABC) Mathematical Model
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作者 JIANG Shuo, SONG Lei Management School, Shenyang University of Technology, Shenyang 110023, P.R.China 《International Journal of Plant Engineering and Management》 2003年第4期210-214,共5页
Along with the product price competition growing intensely, it is apparently important for reasonably distributing and counting cost. But, in sharing indirect cost, traditional cost accounting unveils the limitations ... Along with the product price competition growing intensely, it is apparently important for reasonably distributing and counting cost. But, in sharing indirect cost, traditional cost accounting unveils the limitations increasingly, especially in authenticity of cost information. And the accounting theory circles and industry circles begin seeking one kind of new accurate cost calculation method, and the activity based cost (ABC) method emerges as the times require. In this paper, we will build its mathematical model by the basic principle of ABC, and will improve its mathematical model further. We will establish its comparison mathematical model and make the ABC method go a step further to its practical application. 展开更多
关键词 cost management comparison mathematical model activity based cost(ABC) cost driver cost pool
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Evaluation of Spring Persistent Rainfall over East Asia in CMIP3/CMIP5 AGCM Simulations 被引量:6
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作者 张洁 Laurent LI +1 位作者 周天军 辛晓歌 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第6期1587-1600,共14页
The progress made fi'om Phase 3 to Phase 5 of the Coupled Model Intercomparison Project (CMIP3 to CMIP5) in simulating spring persistent rainfall (SPR) over East Asia was examined from the outputs of nine atmosph... The progress made fi'om Phase 3 to Phase 5 of the Coupled Model Intercomparison Project (CMIP3 to CMIP5) in simulating spring persistent rainfall (SPR) over East Asia was examined from the outputs of nine atmospheric general circulation models (AGCMs). The majority of the models overestimated the precipitation over the SPR domain, with the mean latitude of the SPR belt shifting to the north. The overestimation was about 1mm d-1 in the CMIP3 ensemble, and the northward displacement was about 3°, while in the CMIP5 ensemble the overestimation was suppressed to 0.7 mm d-i and the northward shift decreased to 2.5°. The SPR features a northeast-southwest extended rain belt with a slope of 0.4°N/°E. The CMIP5 ensemble yielded a smaller slope (0.2°N/°E), whereas the CMIP3 ensemble featured an unre- alistic zonally-distributed slope. The CMIP5 models also showed better skill in simulating the interannual variability of SPR. Previous studies have suggested that the zonal land-sea thermal contrast and sensible heat flux over the southeastern Tibetan Plateau are important for the existence of SPR. These two ther- mal factors were captured well in the CMIP5 ensemble, but underestimated in the CMIP3 ensemble. The variability of zonal land-sea thermal contrast is positively correlated with the rainfall amount over the main SPR center, but it was found that an overestimated thermal contrast between East Asia and South China Sea is a common problem in most of the CMIP3 and CMIP5 models. Simulation of the meridional thermal contrast is therefore important for the future improvement of current AGCMs. 展开更多
关键词 model comparison CMIP3 CMIP5 spring persistent rainfall (SPR) atmospheric general circulation model (AGCM)
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The Investigation of Atmospheric Angular Momentum as a Contributor to Polar Wobble and Length of Day Change with AMIP II GCM Data 被引量:1
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作者 钟敏 闫昊明 朱耀仲 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2002年第2期287-296,共10页
The atmospheric angular momentum (AAM) functions in terms of contribution to polar wobble and length of day change, are calculated from the output data of GSM9603 global circulation model (GCM) of Japan Meteorological... The atmospheric angular momentum (AAM) functions in terms of contribution to polar wobble and length of day change, are calculated from the output data of GSM9603 global circulation model (GCM) of Japan Meteorological Agency (JMA), from the reanalysis data of the National Centers for the Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR), and from the operational objective analysis data of JMA, respectively. The comparison shows that during the period from 1985 to 1995, the values of the pressure terms in the equatorial components of AAM functions calculated from three data sets agree with each other better along 90°E longitude than along Greenwich meridian direction. The axial component of relative AAM function estimated from GSM 9603 agrees well with those from the other two data sets in terms of seasonal variations with the moderate amplitudes, but not so well with the composite axial component of relative AAM functions estimated from 23 GCM models anticipating in the first phase of AMIP. In addition, its interannual variation from 1979 to 1996 shows the main characteristics of ENSO evolution, just as does the axial component of relative AAM function estimated from NCEP reanalysis data except for the period of anomalous ENSO from 1991 to 1993. 展开更多
关键词 Atmospheric model Inter–comparison Project (AMIP) Atmospheric Angular Momentum (AAM) Earth rotation
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Argumentative Comparative Analysis of Machine Learning on Coronary Artery Disease 被引量:1
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作者 Keshab R. Dahal Yadu Gautam 《Open Journal of Statistics》 2020年第4期694-705,共12页
Cardiovascular disease (CVD) is a leading cause of death across the globe. Approximately 17.9 million of people die globally each year due to CVD, </span><span style="font-family:Verdana;">which ... Cardiovascular disease (CVD) is a leading cause of death across the globe. Approximately 17.9 million of people die globally each year due to CVD, </span><span style="font-family:Verdana;">which comprises 31% of all death. Coronary Artery Disease (CAD) is a common</span><span style="font-family:Verdana;"> type of CVD and is considered fatal.</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">Predictive models that use machine learning algorithms may assist health workers in timely detection of CAD which ultimately reduce</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the mortality.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">The main purpose of this study is to build a predictive model that provides doctors and health care providers with personalized information to implement better and more personalized treat</span><span style="font-family:Verdana;">ments for their patients. In</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">this study, we use the publicly available Z-Alizadeh</span><span style="font-family:Verdana;"> Sani dataset which contains random samples of 216 cases with CAD and 87 normal controls with 56 different features. The binary variable “Cath” which represents case-control status, is used the target variable. We study its relationship with other predictors and develop classification models using the five different supervised classification machine learning algorithms: Logistic Regression (LR), Classification Tree</span><span style="font-family:""> </span><span style="font-family:Verdana;">with</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">Bagging (Bagging CART), </span><span style="font-family:Verdana;">Random </span><span style="font-family:Verdana;">Forest (RF), Support Vector Machine (SVM), and K-Nearest Neighbors (KNN).</span><span style="font-family:Verdana;"> These five classification models are used to investigate the detection of CAD. Finally, the performance of the machine learning algorithms is compared,</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">and the best model is selected. Our results indicate that the SVM model is able to predict the presence of CAD more effectively and accurately than other models with an accuracy of 0.8947, sensitivity of 0.9434, specificity of 0.7826, and AUC of 0.8868. 展开更多
关键词 Machine Learning Classification model Comparison Coronary Artery Disease Data Mining
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Modeling the distribution of Populus euphratica in the Heihe River Basin, an inland river basin in an arid region of China 被引量:15
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作者 Yanlong GUO Xin LI +1 位作者 Zefang ZHAO Haiyan WEI 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第11期1669-1684,共16页
Populus euphratica is a dominant tree species in riparian Tugai forests and forms a natural barrier that maintains the stability of local oases in arid inland river basins. Despite being critical information for local... Populus euphratica is a dominant tree species in riparian Tugai forests and forms a natural barrier that maintains the stability of local oases in arid inland river basins. Despite being critical information for local environmental protection and recovery, establishing the specific spatial distribution of P. euphratica has rarely been attempted via precise and reliable species distribution models in such areas. In this research, the potential geographic distribution of P. euphratica in the Heihe River Basin was simulated with MaxEnt software based on species occurrence data and 29 environmental variables. The result showed that in the Heihe River Basin, 820 km^2 of land primarily distributed along the banks of the lower reaches of the river is a suitable habitat for P. euphratica. We built other MaxEnt models based on different environmental variables and another eight models employing different mathematical algorithms based on the same 29 environmental variables to demonstrate the superiority of this method.MaxEnt based on 29 environmental variables performed the best among these models, as it precisely described the essential characteristics of the distribution of P. euphratica forest land. This study verified that MaxEnt can serve as an effective tool for species distribution in extremely arid regions with sufficient and reliable environmental variables. The results suggest that there may be a larger area of P. euphratica forest distribution in the study area and that ecological conservation and management of P.euphratica should prioritize suitable habitat. This research provides valuable insights for the conservation and management of degraded P. euphratica riparian forests. 展开更多
关键词 Populus euphratica MAXENT Species distribution models model comparison Inland river basin
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Flux Footprint Climatology Estimated by Three Analytical Models over a Subtropical Coniferous Plantation in Southeast China 被引量:8
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作者 张慧 温学发 《Journal of Meteorological Research》 SCIE CSCD 2015年第4期654-666,共13页
Spatial heterogeneity poses a major challenge for the appropriate interpretation of eddy covariance data. The quantification of footprint climatology is fundamental to improving our understanding of carbon budgets, as... Spatial heterogeneity poses a major challenge for the appropriate interpretation of eddy covariance data. The quantification of footprint climatology is fundamental to improving our understanding of carbon budgets, assessing the quality of eddy covariance data, and upscaling the representativeness of a tower flux to regional or global scales. In this study, we elucidated the seasonal variation of flux footprint climatologies and the major factors that influence them using the analytical FSAM (Flux Source Area Model), KM (Kormann and Meixner, 2001), and H (Hsieh et al., 2000) models based on eddy covariance measurements at two and three times the canopy height at the Qianyanzhou site of ChinaFLUX in 2003. The differences in footprints among the three models resulted from different underlying theories used to construct the models. A comparison demonstrated that atmospheric stability was the main factor leading to differences among the three models. In neutral and stable conditions,the KM and FSAM values agreed with each other, but they were both lower than the H values. In unstable conditions, the agreement among the three models for rough surfaces was better than that for smooth surfaces, and the models showed greater agreement for a low measurement height than for a high measurement height. The seasonal flux footprint climatologies were asymmetrically distributed around the tower and corresponded well to the prevailing wind direction, which was north-northwest in winter and south-southeast in summer. The average sizes of the 90% flux footprint climatologies were 0.36 0.74 and 1.5-3.2 kin2 at altitudes of two and three times the canopy height, respectively. The average sizes were ranked by season as follows: spring 〉 summer 〉 winter 〉 autumn. The footprint climatology depended more on atmospheric stability on daily scale than on seasonal scale, and it increased with the increasing standard deviation of the lateral wind fluctuations. 展开更多
关键词 eddy covariance flux footprint flux footprint climatology model comparison
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ON THE RELATIONSHIP BETWEEN PLANETARY AND SURFACE ALBEDO:MODEL'S COMPARISON AND VALIDATION 被引量:3
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作者 钟强 吴艾笙 《Acta meteorologica Sinica》 SCIE 1995年第4期402-411,共10页
The simple linear relationship between clear-sky planetary and surface albedo can be adopted for certain accuracy.There are different parameterization schemes of atmospheric correction for different retrieval models.I... The simple linear relationship between clear-sky planetary and surface albedo can be adopted for certain accuracy.There are different parameterization schemes of atmospheric correction for different retrieval models.In this paper,several representative retrieval models are compared and tested with observational data from HEIhe basin Field Experiment (HEIFE) in western China.Some evaluations and suggestions on improvement are proposed for models which would be more applicable to plateau and arid areas. 展开更多
关键词 planetary albedo surface albedo modelling comparison
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