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Efficient ECG classification based on Chi-square distance for arrhythmia detection
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作者 Dhiah Al-Shammary Mustafa Noaman Kadhim +2 位作者 Ahmed M.Mahdi Ayman Ibaida Khandakar Ahmedb 《Journal of Electronic Science and Technology》 EI CAS CSCD 2024年第2期1-15,共15页
This study introduces a new classifier tailored to address the limitations inherent in conventional classifiers such as K-nearest neighbor(KNN),random forest(RF),decision tree(DT),and support vector machine(SVM)for ar... This study introduces a new classifier tailored to address the limitations inherent in conventional classifiers such as K-nearest neighbor(KNN),random forest(RF),decision tree(DT),and support vector machine(SVM)for arrhythmia detection.The proposed classifier leverages the Chi-square distance as a primary metric,providing a specialized and original approach for precise arrhythmia detection.To optimize feature selection and refine the classifier’s performance,particle swarm optimization(PSO)is integrated with the Chi-square distance as a fitness function.This synergistic integration enhances the classifier’s capabilities,resulting in a substantial improvement in accuracy for arrhythmia detection.Experimental results demonstrate the efficacy of the proposed method,achieving a noteworthy accuracy rate of 98% with PSO,higher than 89% achieved without any previous optimization.The classifier outperforms machine learning(ML)and deep learning(DL)techniques,underscoring its reliability and superiority in the realm of arrhythmia classification.The promising results render it an effective method to support both academic and medical communities,offering an advanced and precise solution for arrhythmia detection in electrocardiogram(ECG)data. 展开更多
关键词 Arrhythmia classification chi-square distance Electrocardiogram(ECG)signal Particle swarm optimization(PSO)
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Chi-Square and PCA Based Feature Selection for Diabetes Detection with Ensemble Classifier
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作者 Vaibhav Rupapara Furqan Rustam +2 位作者 Abid Ishaq Ernesto Lee Imran Ashraf 《Intelligent Automation & Soft Computing》 SCIE 2023年第5期1931-1949,共19页
Diabetes mellitus is a metabolic disease that is ranked among the top 10 causes of death by the world health organization.During the last few years,an alarming increase is observed worldwide with a 70%rise in the dise... Diabetes mellitus is a metabolic disease that is ranked among the top 10 causes of death by the world health organization.During the last few years,an alarming increase is observed worldwide with a 70%rise in the disease since 2000 and an 80%rise in male deaths.If untreated,it results in complications of many vital organs of the human body which may lead to fatality.Early detection of diabetes is a task of significant importance to start timely treatment.This study introduces a methodology for the classification of diabetic and normal people using an ensemble machine learning model and feature fusion of Chi-square and principal component analysis.An ensemble model,logistic tree classifier(LTC),is proposed which incorporates logistic regression and extra tree classifier through a soft voting mechanism.Experiments are also performed using several well-known machine learning algorithms to analyze their performance including logistic regression,extra tree classifier,AdaBoost,Gaussian naive Bayes,decision tree,random forest,and k nearest neighbor.In addition,several experiments are carried out using principal component analysis(PCA)and Chi-square(Chi-2)fea-tures to analyze the influence of feature selection on the performance of machine learning classifiers.Results indicate that Chi-2 features show high performance than both PCA features and original features.However,the highest accuracy is obtained when the proposed ensemble model LTC is used with the proposed fea-ture fusion framework-work which achieves a 0.85 accuracy score which is the highest of the available approaches for diabetes prediction.In addition,the statis-tical T-test proves the statistical significance of the proposed approach over other approaches. 展开更多
关键词 Diabetes mellitus prediction feature fusion ensemble classifier principal component analysis chi-square
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Efficacy of fexuprazan compared with rebamipide in Korean patients with gastritis:A matching-adjusted indirect comparison
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作者 Gwang Ha Kim Hang Lak Lee 《World Journal of Clinical Cases》 SCIE 2024年第19期3890-3897,共8页
BACKGROUND Gastritis is one of the most frequently diagnosed diseases requiring medical treatment in South Korea.Fexuprazan,a novel potassium-competitive acid blocker,has been approved for treating gastritis and erosi... BACKGROUND Gastritis is one of the most frequently diagnosed diseases requiring medical treatment in South Korea.Fexuprazan,a novel potassium-competitive acid blocker,has been approved for treating gastritis and erosive esophagitis.Meanwhile,rebamipide is the most commonly used mucoprotective agent for acute and chronic gastritis in real-world settings in South Korea.However,there have been no studies comparing the efficacy of these two drugs yet.AIM To compare the efficacy of fexuprazan with that of rebamipide for acute and chronic gastritis.METHODS This was a matching-adjusted indirect comparison.Individual patient data from a phase III study of fexuprazan(10 mg BID)were compared with cumulative data from two matching studies of rebamipide(100 mg TID).Erosion improvement and healing rates were compared between two weeks of fexurapan,two weeks of rebamipide,and four weeks of rebamipide.The two main outcome variables were presented as percentages,and the risk differences(RD)and 95%confidence intervals(CI)were calculated for the relative treatment effects.RESULTS In the primary analysis,the erosion improvement and healing rates after a twoweek treatment with fexuprazan were 64.5%and 53.2%,respectively,while a twoweek treatment with rebamipide resulted in erosion improvement and healing rates of 43.6%(RD:21.0%;95%CI:9.6-32.3;P<0.01)and 35.6%(RD:17.6%;95%CI:6.1-29.2;P=0.003),respectively.In the additional analysis,the erosion improvement and healing rates for the two-week fexuprazan treatment(64.2%and 51.2%,respectively)were similar to those obtained during a four-week treatment with rebamipide(60.6%;RD:3.6%;95%CI:-9.8,17.0;P=0.600 and 53.5%;RD:-2.3%;95%CI:-16.1,11.5;P=0.744,respectively).CONCLUSION The two-week fexuprazan treatment was superior to the two-week rebamipide treatment and similar to the fourweek rebamipide treatment for patients with gastritis. 展开更多
关键词 GASTRITIS Erosive gastritis Fexuprazan REBAMIPIDE Matching-adjusted indirect comparison Indirect treatment comparison
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Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering
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作者 Xingjun Li Dan Yu +1 位作者 Søren Byg Vilsen Daniel Ioan Stroe 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期591-604,共14页
State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging pro... State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application. 展开更多
关键词 Feature engineering Dynamic forklift aging profile State of health comparison Machine learning Lithium-ion batteries
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Efficacy comparison of multipoint and single point scanning panretinal laser photocoagulation in non-proliferative diabetic retinopathy treatment
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作者 Yang-Zhou Zhang Hua Gong +2 位作者 Juan Yang Ji-Pu Bu Hui-Ling Yang 《World Journal of Diabetes》 SCIE 2024年第8期1734-1741,共8页
BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate... BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate the risk of progressing to proliferative diabetic retinopathy(PDR).AIM To compare the efficacy and safety of multi-spot vs single-spot scanning panretinal laser photocoagulation in NPDR patients.METHODS Forty-nine NPDR patients(86 eyes)treated between September 2020 and July 2022 were included.They were randomly allocated into single-spot(n=23,40 eyes)and multi-spot(n=26,46 eyes)groups.Treatment outcomes,including bestcorrected visual acuity(BCVA),central macular thickness(CMT),and mean threshold sensitivity,were assessed at predetermined intervals over 12 months.Adverse reactions were also recorded.RESULTS Energy levels did not significantly differ between groups(P>0.05),but the multi-spot group exhibited lower energy density(P<0.05).BCVA and CMT improvements were noted in the multi-spot group at one-month posttreatment(P<0.05).Adverse reaction incidence was similar between groups(P>0.05).CONCLUSION While energy intensity and safety were comparable between modalities,multi-spot scanning demonstrated lower energy density and showed superior short-term improvements in BCVA and CMT for NPDR patients,with reduced laser-induced damage. 展开更多
关键词 Panretinal laser photocoagulation Non-proliferative diabetic retinopathy Efficacy comparison Multipoint Single point Treatment assessment
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Global Research Progress on Municipal Waste and Future Prospect Based on the Cross-national Comparisons
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作者 ZHANG Yuxin LIU Xiaoqian +2 位作者 YAN Xiaoxia MA Sike MAO Weiyun 《Chinese Geographical Science》 SCIE CSCD 2024年第2期250-264,共15页
Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an sustainability.To elucidate historical trends,current focal points,and future directions in MW ... Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an sustainability.To elucidate historical trends,current focal points,and future directions in MW research,we conducted a bibliometric analysis and employed knowledge graph visualization to scrutinize a total of 34212 articles,which were published between 1991 and 2021 in the Web of Science(WoS)core database.The results indicated that current major research themes encompass waste classifica-tion and recycling,waste management and public behavior,waste disposal methods and technologies,as well as environmental impact and evaluation.There has been a shift in the research focus from the environmental impacts of waste incineration to sustainable manage-ment related issues.A comparison of research from six typical countries revealed the differences in research priorities and techniques advantages.Scholars from the USA and Britain initiated MW research earlier than other countries and investigated management issues in depth,such as public behavior and willingness to pay.Meanwhile,Japanese,German,and Swedish scholars conducted extensive studies on advanced waste treatment technologies,such as disposal and recycling,risk assessment,and waste-to-energy techniques.Chinese scholars placed particular emphasis on end-of-pipe treatments and their associated environmental impacts.Hotspots and poten-tial future frontiers were identified by burst detection analysis.Keywords with high value of burst index(BI)worldwide are food waste and circular economy.Chinese scholars have put great efforts on waste environmental impact and its recycling technologies,while we’re expecting to further investigating vulnerable population.Furthermore,this study contributes to bridging the regional gap of scientific research among different countries and fostering international collaboration. 展开更多
关键词 BIBLIOMETRICS municipal waste(MW) CiteSpace hotspot prediction burst index(BI) SUSTAINABILITY cross-national comparison Web of Science(WoS)
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Comparison and Selection of Water Restoration Techniques for Artificial Landscape Lakes in Nantong City
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作者 Shengrong YAN Yuyue MA +2 位作者 Yi'an CHEN Jiafeng SUN Mingqing CHEN 《Agricultural Biotechnology》 2024年第3期90-92,95,共4页
As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable... As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable homes.Taking the urban water system of Nantong as an example,Nantong Water Resources Bureau issued R evision of Nantong Urban Water System Planning in 2017,and put forward the construction of the"two circles,eight lakes and nine veins"water system layout,giving new vitality to the urban water system.In view of problems existing in newly excavated artificial landscape lakes,such as fragile water ecosystem,strong eutrophication trend,poor environmental sensory effect and unsatisfactory water landscape effect,it is urgent to study the in-situ water ecological restoration technique of"algae-controlling zooplankton+submerged plant community"to build a"grass-type clear water"ecosystem for artificial landscape lakes,so as to improve the water sensory index and self-purification ability and finally realize the double improvement of"sensory effect and water quality"of artificial landscape lakes. 展开更多
关键词 Water body remediation technique Artificial landscape lake comparison and selection Nantong City
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Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen
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作者 Troy Myers Michael A.Sutton +2 位作者 Hubert Schreier Alistair Tofts Sreehari Rajan Kattil 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1263-1298,共36页
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is... To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process. 展开更多
关键词 StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation
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Does US Dollar Supply Trigger House Price Fluctuations?An International Comparison
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作者 Zihan Wang Yikun Huang 《Proceedings of Business and Economic Studies》 2024年第5期55-60,共6页
Cyclical fluctuations in asset prices are closely related to the overall stability of the macroeconomy and have thus become a significant topic in academic and professional exploration.Among these fluctuations,changes... Cyclical fluctuations in asset prices are closely related to the overall stability of the macroeconomy and have thus become a significant topic in academic and professional exploration.Among these fluctuations,changes in the supply of the U.S.dollar,the global reserve,and primary settlement currency have a broad and far-reaching impact on international financial markets.Since COVID-19,asset prices across various countries have shown differing trends due to fluctuations in the U.S.dollar supply.Housing prices,a key focus in asset pricing research,have been affected to varying degrees.This thesis utilizes seven house price indices from representative cities worldwide from 2020 to 2023 to compare the differential impacts across various countries using an empirical approach.The results indicate that the impact of the U.S.dollar money supply(M2)diminishes in a gradient from the U.S.to East Asia,and then to Europe. 展开更多
关键词 Dollar supply Quantitative easing Property prices International comparisons
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Comparison of the Development of CDMO at Home and Abroad and Its Enlightment to China
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作者 Zhao Meng Huang Zhe 《Asian Journal of Social Pharmacy》 2024年第3期244-250,共7页
Objective To analyze the development status of contract development manufacturing organization(CDMO)at home and abroad,and to make some suggestions for the development of CDMO in China.Methods The relevant literature ... Objective To analyze the development status of contract development manufacturing organization(CDMO)at home and abroad,and to make some suggestions for the development of CDMO in China.Methods The relevant literature was searched and reviewed,and the development status of CDMOs in the United States,France,Japan and China was compared from the aspects of market scale,development process,development focus,advantages and disadvantages,and policy support.Then,some suggestions for the development of CDMO enterprises in China were summarized.Results and Conclusion Through the comparison of CDMO development at home and abroad,it can be seen that China started CDMO late,there were many technical barriers and its globalization layout were not sufficient.However,the development trend was good and it focused on the field of chemical drugs and biological drugs to constantly develop innovative drugs.China needs to continuously improve its own technical capabilities to carry out innovative research.Therefore,cost reduction and efficiency increase will be the key elements for the development of CDMOs,and they are expected to have a rapid and comprehensive development in the future. 展开更多
关键词 CDMO current situation of enterprise development domestic and international comparison policy implications
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单值分解和Chi-square技术在生化反应过程控制中的应用
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作者 李延科 张淑芬 杨锦宗 《化工学报》 EI CAS CSCD 北大核心 2003年第9期1326-1329,共4页
In this paper Singular Decompositon Value (SVD) formula and modified Chi-square solution are provided, and the modified Chi-square is combined with FT-IR instrument to control biochemical reaction process. Using the m... In this paper Singular Decompositon Value (SVD) formula and modified Chi-square solution are provided, and the modified Chi-square is combined with FT-IR instrument to control biochemical reaction process. Using the modified Chi-square technique, the unknown concentration of reactants and products in test samples withdrawn from the process is determined. The technique avoids the need for the spectral data to conform to Beer’s Law and the best spectral range is determined automatically. 展开更多
关键词 单值分解 chi-square FT-IR波谱仪 过程控制
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基于Chi-square检验的分布式网络入侵检测系统
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作者 张明辉 李俭 张秋芳 《微计算机信息》 2010年第15期98-99,92,共3页
针对网络攻击的新特点,本文提出了一种基于Chi-square检验的分布式网络入侵检测系统模型CTDIDS。设计并实现了一个基于异常检测的入侵分析引擎。通过对网络数据包的分析,运用Chi-square值比较对系统的行为进行检测。与现有的入侵检测方... 针对网络攻击的新特点,本文提出了一种基于Chi-square检验的分布式网络入侵检测系统模型CTDIDS。设计并实现了一个基于异常检测的入侵分析引擎。通过对网络数据包的分析,运用Chi-square值比较对系统的行为进行检测。与现有的入侵检测方法相比,本文提出的方法具有更好的环境适应性和数据协同分析能力。实验证明,分布式入侵检测系统CTDIDS具有更高的准确性和扩展性。 展开更多
关键词 入侵检测 分布式 chi-square检验
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Visualising data distributions with kernel density estimation and reduced chi-squared statistic 被引量:8
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作者 C.J.Spencer C.Yakymchuk M.Ghaznavi 《Geoscience Frontiers》 SCIE CAS CSCD 2017年第6期1247-1252,共6页
The application of frequency distribution statistics to data provides objective means to assess the nature of the data distribution and viability of numerical models that are used to visualize and interpret data.Two c... The application of frequency distribution statistics to data provides objective means to assess the nature of the data distribution and viability of numerical models that are used to visualize and interpret data.Two commonly used tools are the kernel density estimation and reduced chi-squared statistic used in combination with a weighted mean.Due to the wide applicability of these tools,we present a Java-based computer application called KDX to facilitate the visualization of data and the utilization of these numerical tools. 展开更多
关键词 Data visualisation KERNEL DENSITY estimation REDUCED chi-squared statistic Mean SQUARE WEIGHTED deviation GEOSTATISTICS
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平“语”近人中课程思政元素comparison的应用及分析
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作者 武悦 《海外英语》 2023年第13期85-87,共3页
文章的研究目的是理解平“语”近人中comparison(比喻)的用法,平“语”近人中课程思政的内容和其背后的真实含义具有重要的教育意义。文章以话语中课程思政元素的comparison主要例子作为研究对象,来探讨和研究平“语”近人话语中的关于c... 文章的研究目的是理解平“语”近人中comparison(比喻)的用法,平“语”近人中课程思政的内容和其背后的真实含义具有重要的教育意义。文章以话语中课程思政元素的comparison主要例子作为研究对象,来探讨和研究平“语”近人话语中的关于comparison的应用并且加以分析。 展开更多
关键词 平“语”近人 课程思政元素 comparison应用分析
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大锻件统计学Chi-square test的研究和应用 被引量:3
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作者 齐作玉 吕亚臣 任运来 《大型铸锻件》 2011年第1期9-11,25,共4页
根据大锻件生产的特点和统计学的基本理论方法,首次深入浅出地论述了大锻件的Chi-square test,即X2检验,并给出了具体应用示例。该方法可用于大锻件工艺参数的科学分析和生产验证,可用于大锻件质量分析和判断,可帮助逐步建立起大锻件的... 根据大锻件生产的特点和统计学的基本理论方法,首次深入浅出地论述了大锻件的Chi-square test,即X2检验,并给出了具体应用示例。该方法可用于大锻件工艺参数的科学分析和生产验证,可用于大锻件质量分析和判断,可帮助逐步建立起大锻件的工序能力,帮助实现稳定并提升大锻件工艺和质量控制水平。 展开更多
关键词 大锻件 chi-square TEST 统计学
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Optimization Method of Suspected Electricity Theft Topic Model Based on Chi-square Test and Logistic Regression 被引量:1
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作者 Jian Dou Ye Aliaosha 《国际计算机前沿大会会议论文集》 2018年第2期32-32,共1页
关键词 Anti-electricity THEFT chi-square test LOGISTIC regressionPower consumption inspection
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Multiomics comparison among populations of three plant sources of Amomi Fructus 被引量:1
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作者 Xinlian Chen Shichao Sun +15 位作者 Xiaoxu Han Cheng Li Fengjiao Wang Bao Nie Zhuangwei Hou Song Yang Jiaojiao Ji Ge Li Yanqian Wang Xiaoyu Han Jianjun Yue Cui Li Wei Li Lixia Zhang Depo Yang Li Wang 《Horticulture Research》 SCIE CSCD 2023年第8期129-142,共14页
Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV... Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV has been transplanted from its top-geoherb region,Guangdong,to its current main production area,Yunnan,for>50 years in China.However,the genetic and transcriptomic differentiation among multiple AF source species(or varieties)and between the origin and transplanted populations of WVV is unknown.In our study,the observed overall higher expression of terpenoid biosynthesis genes in WVV than in WVX provided possible evidence for the better pharmacological effect of WVV.We also screened six candidate borneol dehydrogenases(BDHs)that potentially catalyzed borneol into camphor in WVV and functionally verified them.Highly expressed genes at the P2 stage of WVV,Wv05G1424 and Wv05G1438,were capable of catalyzing the formation of camphor from(+)-borneol,(-)-borneol and DL-isoborneol.Moreover,the BDH genes may experience independent evolution after acquiring the ancestral copies,and the following tandem duplications might account for the abundant camphor content in WVV.Furthermore,four populations of WVV,WVX,and WL are genetically differentiated,and the gene flow from WVX to WVV in Yunnan contributed to the greater genetic diversity in the introduced population(WVV-JH)than in its top-geoherb region(WVV-YC),which showed the lowest genetic diversity and might undergo genetic degradation.In addition,terpene synthesis(TPS)and BDH genes were selected among populations of multiple AF source species(or varieties)and between the top-and non-top-geoherb regions,which might explain the difference in metabolites between these populations.Our findings provide important guidance for the conservation,genetic improvement,and industrial development of the three source species(or varieties)and for identifying top-geoherbalism with molecular markers,and proper clinical application of AF. 展开更多
关键词 HERBAL AMONG comparison
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Large Deviations and Moderate Deviations for the Chi-Square Test in Type Ⅱ Error
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作者 JIANG Hui GAO Fuqing 《Wuhan University Journal of Natural Sciences》 CAS 2008年第2期129-132,共4页
We study the asymptotics tot the statistic of chi-square in type Ⅱ error. By the contraction principle, the large deviations and moderate deviations are obtained, and the rate function of moderate deviations can be c... We study the asymptotics tot the statistic of chi-square in type Ⅱ error. By the contraction principle, the large deviations and moderate deviations are obtained, and the rate function of moderate deviations can be calculated explicitly which is a squared function. 展开更多
关键词 large deviations moderate deviations chi-square test
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First acceptance testing of multiple A10 absolute gravimeters in China and analysis of the comparison results 被引量:2
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作者 Xiaotong Zhang Hao Zhou +4 位作者 Ying Jiang Dulin Zhai Gongzhe Wei Hui Li Ziwei Liu 《Geodesy and Geodynamics》 EI CSCD 2023年第4期401-410,共10页
Three A10 absolute gravimeters(AGs) were first acquired in China by the Hubei Earthquake Agency under the Belt and Road Seismic Monitoring Network Project. Although AG measuring and testing technique is not new, the p... Three A10 absolute gravimeters(AGs) were first acquired in China by the Hubei Earthquake Agency under the Belt and Road Seismic Monitoring Network Project. Although AG measuring and testing technique is not new, the purchase and simultaneous testing of 3 A10 absolute gravimeters is unprecedented in China. This study conducted the first acceptance testing of the AGs at 3 locations(the Jiufengshan Gravity Observation Station, the Global Navigation Satellite System Observation Station in Wuhan, and the Jiugongshan Observation Station in Xianning). The results were compared using a method based on expert validation, and the acceptance testing scheme was formulated by referring to the Technical Regulations for Tectonic Environment Monitoring Networks in China and Specifications for Gravimetry Control. Based on the repeatability, precision, and consistency of the measured g values, the results from each instrument were evaluated using the air pressure precision test. Comparing the instrument reference values, the final test results can identify the indicator parameters for 3 A10 AGs, the effects of the surrounding environment, and the related parameters on measurement precision. The precision of A10-059, A10-058, and A10-057 exceeded 0.78 μGal, 0.79 μGal, and 0.42 μGal, respectively.This testing scheme can be used as a reference for conducting acceptance testing of AGs in the future and obtaining absolute gravimetric measurements. 展开更多
关键词 Gravitational acceleration comparison of absolute gravimeters A10 absolute gravimeters Instrument precision
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Natural gas characteristics and gas-source comparisons of the Lower Triassic Feixianguan Formation,Eastern Sichuan Basin,China 被引量:1
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作者 Zi-Yun Zheng Yin-Hui Zuo +5 位作者 Hua-Guo Wen De-Ming Li Yang Luo Jia-Zhen Zhang Mei-Hua Yang Jian-Cheng Zeng 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1458-1470,共13页
There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Fe... There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Feixianguan Formation and thus hampers natural gas exploration in the region,so further study is urgently required.Using experimental tests of natural gas composition,stable isotopes,and noble gas isotopes with gas chromatography(GC)and mass spectrometry(MS)studies of source rock and reservoir asphalt saturated hydrocarbons,the natural gas geochemical characteristics,the genetic identification and a gas-source comparison of the Feixianguan Formation were studied.Then,con-strained by the thermal history,the histories of gas generation and expulsion were restored by basin simulation technology.Finally,a gas accumulation model was established for the Feixianguan Formation.The results showed that(1)the H_(2)S-rich and H2S-poor gas reservoirs of the Feixianguan Formation are distributed on the east and west sides of the Kaijiang-Liangping trough in the Eastern Sichuan Basin,respectively.The carbon and hydrogen isotope compositions of the natural gas in the gas reservoirs are generally heavy and have typical characteristics of high-maturity dry gas reservoirs.(2)The natural gas of the Feixianguan Formation is organic thermogenic gas,which is mainly oil-type gas generated by the secondary cracking of crude oil.The gas-generating parent material is mainly type II kerogen.(3)The natural gas of the Feixianguan Formation in the Eastern Sichuan Basin was mainly generated by argil-laceous source rocks of the Upper Permian Longtan Formation.(4)Natural gas accumulation occurred as follows:the paleo-structure heights were filled with crude oil in the Early Jurassic,and paleo-oil res-ervoirs were formed in the Feixianguan Formation;during the Middle-Late Jurassic,the paleo-oil res-ervoirs were cracked when the reservoir temperatures rose above 160 C,and paleo-gas reservoirs were formed.Since the end of the Late Jurassic,the paleo-gas reservoirs have been adjusted and reformed to form the present-day natural gas reservoirs.These results provide a basis for studying natural gas accumulation dynamics of the Feixianguan Formation in the Eastern Sichuan Basin. 展开更多
关键词 Eastern Sichuan Basin Feixianguan Formation Natural gas origin Gas-source comparison Longtan Formation
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