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A complementary approach to quantify the basic GSI chart considering scale effect on rock structure
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作者 Harun Sonmez Gulseren Dagdelenler +1 位作者 Yilmaz Ozcelik Murat Ercanoglu 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第1期154-167,共14页
Geological strength index(GSI)has been widely used as an input parameter in predicting the strength and deformation properties of rock masses.This study derived a series of equations to satisfy the original GSI lines ... Geological strength index(GSI)has been widely used as an input parameter in predicting the strength and deformation properties of rock masses.This study derived a series of equations to satisfy the original GSI lines on the basic GSI chart.Two axes ranging from 0 to 100 were employed for surface conditions of the discontinuities and the structure of rock mass,which are independent of the input parameters.The derived equations can analyze GSI values ranging from 0 to 100 within±5%error.The engineering dimensions(EDs)such as the slope height,tunnel width,and foundation width were used together with representative elementary volume(REV)in jointed rock mass to define scale factor(sf)from 0.2 to 1 in evaluating the rock mass structure including joint pattern.The transformation of GSI into a scaledependent parameter based on engineering scale addresses a crucial requirement in various engineering applications.The improvements proposed in this study were applied to a real slope which was close to the time of failure.The results of stability assessments show that the new proposals have sufficient capability to define rock mass quality considering EDs. 展开更多
关键词 Basic GSI chart Engineering dimension(ED) Hoek and Brown failure criterion Quantification of GSI Quantitative GSI chart Scale effect
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Average Run Length in TEWMA Control Charts:Analytical Solutions for AR(p)Processes and Real Data Applications
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作者 Sirawit Makaew Yupaporn Areepong Saowanit Sukparungsee 《Computer Modeling in Engineering & Sciences》 2025年第5期1617-1634,共18页
This study aims to examine the explicit solution for calculating the Average Run Length(ARL)on the triple exponentially weighted moving average(TEWMA)control chart applied to autoregressive model(AR(p)),where AR(p)is ... This study aims to examine the explicit solution for calculating the Average Run Length(ARL)on the triple exponentially weighted moving average(TEWMA)control chart applied to autoregressive model(AR(p)),where AR(p)is an autoregressive model of order p,representing a time series with dependencies on its p previous values.Additionally,the study evaluates the accuracy of both explicit and numerical integral equation(NIE)solutions for AR(p)using the TEWMA control chart,focusing on the absolute percentage relative error.The results indicate that the explicit and approximate solutions are in close agreement.Furthermore,the study investigates the performance of exponentially weighted moving average(EWMA)and TEWMA control charts in detecting changes in the process,using the relative mean index(RMI)as a measure.The findings demonstrate that the TEWMA control chart outperforms the EWMA control chart in detecting process changes,especially when the value ofλis sufficiently large.In addition,an analysis using historical data from the SET index between January 2024 and May 2024 and historical data of global annual plastic production,the results of both data sets also emphasize the superior performance of the TEWMA control chart. 展开更多
关键词 EWMA control chart TEWMA control charts average run length shift detection explicit formula Fredholm integral equation Banach’s fixed-point theorem AR(p)process
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Rethinking Chart Understanding Using Multimodal Large Language Models
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作者 Andreea-Maria Tanasa Simona-Vasilica Oprea 《Computers, Materials & Continua》 2025年第8期2905-2933,共29页
Extracting data from visually rich documents and charts using traditional methods that rely on OCR-based parsing poses multiple challenges,including layout complexity in unstructured formats,limitations in recognizing... Extracting data from visually rich documents and charts using traditional methods that rely on OCR-based parsing poses multiple challenges,including layout complexity in unstructured formats,limitations in recognizing visual elements,and the correlation between different parts of the documents,as well as domain-specific semantics.Simply extracting text is not sufficient;advanced reasoning capabilities are proving to be essential to analyze content and answer questions accurately.This paper aims to evaluate the ability of the Large Language Models(LLMs)to correctly answer questions about various types of charts,comparing their performance when using images as input versus directly parsing PDF files.To retrieve the images from the PDF,ColPali,a model leveraging state-of-the-art visual languagemodels,is used to identify the relevant page containing the appropriate chart for each question.Google’s Gemini multimodal models were used to answer a set of questions through two approaches:1)processing images derived from PDF documents and 2)directly utilizing the content of the same PDFs.Our findings underscore the limitations of traditional OCR-based approaches in visual document understanding(VrDU)and demonstrate the advantages of multimodal methods in both data extraction and reasoning tasks.Through structured benchmarking of chart question answering(CQA)across input formats,our work contributes to the advancement of chart understanding(CU)and the broader field of multimodal document analysis.Using two diverse and information-rich sources:the World Health Statistics 2024 report by theWorld Health Organisation and the Global Banking Annual Review 2024 by McKinsey&Company,we examine the performance ofmultimodal LLMs across different input modalities,comparing their effectiveness in processing charts as images versus parsing directly from PDF content.These documents were selected due to their multimodal nature,combining dense textual analysis with varied visual representations,thus presenting realistic challenges for vision-language models.This comparison is aimed at assessing how advanced models perform with different input formats and to determine if an image-based approach enhances chart comprehension in terms of accurate data extraction and reasoning capabilities. 展开更多
关键词 chart understanding large language models multimodal models PDF extraction
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Application of Fructo-oligosaccharides Quality Control Chart in Milk Powder
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作者 Guoxia DUAN Lijun LIU +5 位作者 Ruilong XIE Xue HU Lunwei WU Jing CHEN Huili GONG Chunxia LIU 《Asian Agricultural Research》 2025年第1期35-37,共3页
The quality control chart of fructo-oligosaccharides in milk powder was established to determine whether the detection process and results are in control state.The content of fructo-oligosaccharides in milk powder con... The quality control chart of fructo-oligosaccharides in milk powder was established to determine whether the detection process and results are in control state.The content of fructo-oligosaccharides in milk powder control samples was determined by ion chromatography,and the quality control chart of fructo-oligosaccharides was established to analyze the controlled state.The results indicate that the median of the quality control chart is 1613.14 mg/100 g,and the standard deviation is 85.57 mg/100 g.The new quality control points were evaluated and analyzed,and the precision changed,but the mean value did not change.Further F test was conducted to determine that the precision did not change significantly,indicating that the test was in a statistical control state,and the detection process,method and results were controlled. 展开更多
关键词 Quality control chart FRUCTO-OLIGOSACCHARIDES Milk powder
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The ICS international chronostratigraphic chart this decade
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作者 Kim Cohen David Harper +1 位作者 Philip Gibbard Nicholas Car 《Episodes》 2025年第1期105-115,共11页
The International Commission on Stratigraphy(ICS)has been producing and updating its International Chro-nostratigraphic Chart for several decades.The chart communicates higher-order divisions of geological time and ac... The International Commission on Stratigraphy(ICS)has been producing and updating its International Chro-nostratigraphic Chart for several decades.The chart communicates higher-order divisions of geological time and actual knowledge on the numerical ages of their bound-aries.Distributed via the ICS website www.stratigraphy.org the chart promotes use in graphic,tabulated and further digital forms in multiple languages.This paper is a status update,eleven years since the last such publication,cov-ering activities between 2012 and 2024.Chart updates during the past decade have echoed the ICS’s primary objective of precisely defining a global standard set of time-correlative units(Systems,Series,Stages)for stratigraphic successions worldwide.These units are,in turn,the basis for the Periods,Epochs,and Ages of the Geological Time Scale.Their standardization is fundamental for expressing geological knowledge,in application and education,out-reach and continuing research.The chart offers a frame-work through which regional-scale higher-resolution divisions can be linked,equated and collated.Likewise it offers a framework for digital representation of the Geological Time Scale.Maintenance and distribution of chart versions on the web has been a manual endeavour,a process that ICS is upgrading to serve an increasingly digital world. 展开更多
关键词 digital representation geological knowledge education standard time correlative units commission stratigraphy ics chronostratigraphic chart geological time scale international commission stratigraphy
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Effects of herbal medicines containing Paeoniae Radix on patients with restless legs syndrome:A retrospective chart review study
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作者 Young Seon Lee Han-Gyul Lee +6 位作者 Seungwon Kwon Seung-Yeon Cho Woo-Sang Jung Seong-Uk Park Sang-Kwan Moon Jung-Mi Park Chang-Nam Ko 《World Journal of Clinical Cases》 2025年第25期35-45,共11页
BACKGROUND Restless legs syndrome(RLS)is a neurological disorder characterized by an uncontrollable urge to move the legs during rest.Standard treatments may provide short-term relief but are limited by long-term adve... BACKGROUND Restless legs syndrome(RLS)is a neurological disorder characterized by an uncontrollable urge to move the legs during rest.Standard treatments may provide short-term relief but are limited by long-term adverse effects.Herbal medicine containing Paeoniae Radix(HCP)has traditionally been used in Korean medicine to treat RLS symptoms.AIM To investigate the clinical effectiveness and safety of HCP in treating RLS.METHODS This retrospective chart review study included 15 patients with RLS who were treated with HCP between September 2017 and August 2022 at the Kyung Hee University Korean Medicine Hospital.The demographic,disease-related,and treatment-related characteristics,as well as the impressions of each patient,were analyzed.The study also evaluated the changes in the subjective complaints of RLS symptoms,the Korean version of the International Restless Legs Scale(KIRLS)scores before and after treatment,and the adverse events after HCP administration.RESULTS Following HCP administration,14 patients(93.3%)experienced a decrease in the degree of discomfort associated with their symptoms,with an average reduction to 44.7±35.1%compared to their discomfort levels before taking the drug.After treatment,the mean total K-IRLS score decreased significantly from 23.00±9.75 to 13.93±10.9(P=0.005).Among the HCP,a significant reduction in the K-IRLS score was observed in the Gyejibokryeonghwan(26.0±9.7 to 10.0±9.4,P=0.028)and Jakyakgamchotang(23.2±12.6 to 6.6±4.2,P=0.042)groups.Additionally,no adverse events were reported.CONCLUSION HCP improved symptoms in RLS patients.These results suggest that HCP may be an effective and safe alternative for RLS.A randomized controlled trial is required to confirm these findings. 展开更多
关键词 Paeoniae Radix Restless legs syndrome International restless legs scale Herbal medicine Retrospective chart review study
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Clinical usefulness of the baby vision test in young children and its correlation with the Snellen chart
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作者 Ya-Lan Wang Jia-Jun Wang +2 位作者 Xi-Cong Lou Han Zou Yun-E Zhao 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第2期348-352,共5页
AIM:To investigate the efficacy of a new visual acuity(VA)screening method,the baby vision test for young children.METHODS:A total 105 eyes of 65 children aged 2-8y were included in the study.Acuity testing was conduc... AIM:To investigate the efficacy of a new visual acuity(VA)screening method,the baby vision test for young children.METHODS:A total 105 eyes of 65 children aged 2-8y were included in the study.Acuity testing was conducted using a standardized recognition acuity chart(Snellen visual chart:at 3 m)and the baby vision model assessment.The baby vision device includes a screen,a near infrared camera and a computer.Children were seated at a measured distance of 33-40 cm from a display for testing.VA was estimated according to the highest resolution the children could follow.Decimal VA data were converted to logarithm of the minimum angle of resolution(logMAR)for statistical analysis.The VA results for each child were recorded and analyzed for consistency.RESULTS:The mean VA measured using the Snellen visual chart was 0.62±0.32,and that assessed using the baby vision test was 0.66±0.27.The 95%limit of agreement was-0.609 to 0.695,with 95.2%(100/105)plots within the 95%limits of agreement.VA values of the baby vision test were significantly correlated with those of the Snellen chart(R=0.274,P=0.005).CONCLUSION:The baby vision test can be used as a relatively reliable method for estimating VA in young children.This new acuity assessment might be a valid predictor of optotype-measured acuity later in preverbal children. 展开更多
关键词 baby vision test acuity assessment fix-and-follow system Snellen chart
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Modified DS np Chart Using Generalized Multiple Dependent State Sampling under Time Truncated Life Test
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作者 Wimonmas Bamrungsetthapong Pramote Charongrattanasakul 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2471-2495,共25页
This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of t... This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data. 展开更多
关键词 Modified DS np chart generalizedmultiple dependent state sampling time truncated life test Weibull distribution average run length average sample size
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Exploring Variability in Sea Level at a Tide Gauge Station through Control Charts
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作者 H.Bâkiİz 《Journal of Environmental & Earth Sciences》 CAS 2024年第1期11-18,共8页
Monitoring temporal changes in sea level is important in assessing coastal risk.Sea level anomalies at a tide gauge station,if kinematically conceived,include systematic variations such as trend,acceleration,periodic ... Monitoring temporal changes in sea level is important in assessing coastal risk.Sea level anomalies at a tide gauge station,if kinematically conceived,include systematic variations such as trend,acceleration,periodic oscillations,and random disturbances.Among them,the non-stationary nature of the random sea level variations of known or unknown origin at coastal regions has been long recognized by the sea level community.This study proposes the analyses of subgroups of random residual statistics of a rigorously formulated kinematic model solution of tide gauge variations using X-bar and S control charts.The approach is demonstrated using Key West,Florida tide gauge records.The mean and standard errors of 5-year-long subgroups of the residuals revealed that sea level changes at this location have been progressively intensifying from 1913 to the present.Increasing oscillations in sea level at this locality may be attributed partly to the thermal expansion of seawater with increasing temperatures causing larger buoyancy-related sea level fluctuations as well as the intensification of atmospheric events including wind patterns and the impact of changes in inverted barometer effects that will alter coastal risk assessments for the future. 展开更多
关键词 Climate change Sea level variance X-bar S control charts
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Chart features,data quality,and scale in cartographic sounding selection from composite bathymetric data
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作者 Noel Dyer Christos Kastrisios Leila De Floriani 《Geo-Spatial Information Science》 CSCD 2024年第5期1542-1567,共26页
Cartographic sounding selection is a constraint-based bathymetric generalization process for identifying navigationally relevant soundings for nautical chart display.Electronic Navigational Charts(ENCs)are the premier... Cartographic sounding selection is a constraint-based bathymetric generalization process for identifying navigationally relevant soundings for nautical chart display.Electronic Navigational Charts(ENCs)are the premier maritime navigation medium and are produced according to international standards and distributed around the world.Cartographic generalization for ENCs is a major bottleneck in the chart creation and update process,where high volumes of data collected from constantly changing seafloor topographies require tedious examination.Moreover,these data are provided by multiple sources from various collection platforms at different levels of quality,further complicating the generalization process.Therefore,in this work,a comprehensive sounding selection algorithm is presented that focuses on safe navigation,leveraging both the Digital Surface Model(DSM)of multi-source bathymetry and the cartographic portrayal of the ENC.A taxonomy and hierarchy of soundings found on ENCs are defined and methods to identify these soundings are employed.Furthermore,the significant impact of depth contour generalization on sounding selection distribution is explored.Incorporating additional ENC bathymetric features(rocks,wrecks,and obstructions)affecting sounding distribution,calculating metrics from current chart products,and introducing procedures to correct cartographic constraint violations ensures a shoal-bias and mariner-readable output.This results in a selection that is near navigationally ready and complementary to the specific waterways of the area,contributing to the complete automation of the ENC creation and update process for safer maritime navigation. 展开更多
关键词 BATHYMETRY GENERALIZATION CARTOGRAPHY hydrography navigation nautical AUTOMATION Electronic Navigational charts(ENC)
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Establishment and Evaluation of Quality Control Chart of DHA in Milk Powder
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作者 Lijun LIU Guoxia DUAN +4 位作者 Xue HU Chunxia LIU Huili GONG Jing CHEN Lunwei WU 《Asian Agricultural Research》 2024年第12期40-42,共3页
[Objectives]To establish a quality control chart of DHA in milk powder and determine whether the detection process and results are in control state.[Methods]The content of DHA in milk powder control samples was determ... [Objectives]To establish a quality control chart of DHA in milk powder and determine whether the detection process and results are in control state.[Methods]The content of DHA in milk powder control samples was determined by gas chromatography,and the quality control chart of DHA was established to analyze the controlled state.[Results]the median of the quality control chart was 23.85 mg/100 g,and the standard deviation was 1.00 mg/100 g.In the evaluation and analysis of the new quality control points,it can be seen that the point beyond the warning limit was 1,and the outlier value was not beyond the action line,and the mean value did not change,indicating that the detection is in the statistical control state,and the detection process,method and results are controlled.[Conclusions]The establishment and review of the control chart in this study are expected to provide a reference for other subsequent quality controls. 展开更多
关键词 Quality control chart DHA Milk powder
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Japanese candlestick charts for diabetes
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作者 Diana Boj-Carceller 《World Journal of Methodology》 2024年第2期167-171,共5页
Continuous glucose monitoring(CGM)is a popular technology among the diabetic population,especially in patients with type 1 diabetes and those with type 2 diabetes treated with insulin.The American Diabetes Association... Continuous glucose monitoring(CGM)is a popular technology among the diabetic population,especially in patients with type 1 diabetes and those with type 2 diabetes treated with insulin.The American Diabetes Association recommends standardization of CGM reports with visual cues,such as the ambulatory glucose profile.Nevertheless,interpreting this report requires training and time for CGM to be cost-efficient.In this work it has been proposed to incorporate Japanese candlestick charts in glucose monitoring.These graphs are used in price analysis in financial markets and are easier to view.Each candle provides extra information to make prudent decisions since it reports the opening,maximum,minimum and closing glucose levels of the chosen time frame,usually the daily one.The Japanese candlestick chart is an interesting tool to be considered in glucose control.This graphic representation allows identification of glucose trends easily through the colors of the candles and maximum and minimum glucose values. 展开更多
关键词 Japanese candlestick chart Candlestick chart Ambulatory glucose profile Glucose monitoring Continuous glucose monitoring HYPOGLYCEMIA
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包含多维度评价指标的实验设备定量优化配置模型设计 被引量:1
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作者 赵建勇 陈磊磊 +3 位作者 吴敏 年珩 于彦雪 孙丹 《实验室研究与探索》 北大核心 2025年第3期195-200,共6页
针对现阶段实验室建设规划主要以经验法为主、在实验设备配置上缺乏量化建模分析方法的缺点,提出了一种适用于教学实验设备定量规划的多目标优化配置方法。建立的基于改进雷达图的优化配置模型,得到投资成本、运维成本、学生覆盖面、学... 针对现阶段实验室建设规划主要以经验法为主、在实验设备配置上缺乏量化建模分析方法的缺点,提出了一种适用于教学实验设备定量规划的多目标优化配置方法。建立的基于改进雷达图的优化配置模型,得到投资成本、运维成本、学生覆盖面、学生受益率、设备利用率等多个实验室规划建设中重要评价目标综合最优的实验设备配置结果。通过配置与经验法对比结果表明:除运维成本略有增加外,在学生覆盖面、学生受益指数、设备利用率等方面均有明显优势;其多目标优化模型的综合指标取得了最优规划效果。该模型对高校的实验室建设规划提供了参考借鉴。 展开更多
关键词 新工科 实验室规划 多层级实验装置 优化配置 雷达图模型
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基于AHP层次分析法的盘龙城遗址文化基因提取及信息图表设计研究 被引量:6
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作者 张姝 罗静懿 《包装工程》 北大核心 2025年第2期251-260,共10页
目的 旨在依托文化基因理念,探究物质文化遗产的传播方式,助力盘龙城遗址活态化传承,增强人们对盘龙城遗址的关注度与认同感。方法 通过探究文化基因的定义、研究综述与分类方式,以“十四五”时期确定的湖北省武汉市盘龙城遗址为例,提... 目的 旨在依托文化基因理念,探究物质文化遗产的传播方式,助力盘龙城遗址活态化传承,增强人们对盘龙城遗址的关注度与认同感。方法 通过探究文化基因的定义、研究综述与分类方式,以“十四五”时期确定的湖北省武汉市盘龙城遗址为例,提取盘龙城遗址的文化基因,构建盘龙城文化基因谱系图,采用AHP层次分析法进行文化基因评价。结果 运用文化基因理论有效实现了盘龙城遗址文化基因的提取与评价,为盘龙城遗址信息图表设计提供依据。结论 所提出的文化基因提取方法和信息图表设计能够帮助公众快速了解遗址并参与到遗址文化的传承中去。二者结合不仅为其他遗址的传播与推广提供了借鉴,也对未来文化遗产推广的发展方向提出展望。 展开更多
关键词 文化基因 盘龙城遗址 文化基因提取 AHP层次分析法 信息图表设计
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A structural VAR and VECM modeling method for open-high-low-close data contained in candlestick chart
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作者 Wenyang Huang Huiwen Wang Shanshan Wang 《Financial Innovation》 2024年第1期2017-2045,共29页
The structural modeling of open-high-low-close(OHLC)data contained within the candlestick chart is crucial to financial practice.However,the inherent constraints in OHLC data pose immense challenges to its structural ... The structural modeling of open-high-low-close(OHLC)data contained within the candlestick chart is crucial to financial practice.However,the inherent constraints in OHLC data pose immense challenges to its structural modeling.Models that fail to process these constraints may yield results deviating from those of the original OHLC data structure.To address this issue,a novel unconstrained transformation method,along with its explicit inverse transformation,is proposed to properly handle the inherent constraints of OHLC data.A flexible and effective framework for structurally modeling OHLC data is designed,and the detailed procedure for modeling OHLC data through the vector autoregression and vector error correction model are provided as an example of multivariate time-series analysis.Extensive simulations and three authentic financial datasets from the Kweichow Moutai,CSI 100 index,and 50 ETF of the Chinese stock market demonstrate the effectiveness and stability of the proposed modeling approach.The modeling results of support vector regression provide further evidence that the proposed unconstrained transformation not only ensures structural forecasting of OHLC data but also is an effective feature-extraction method that can effectively improve the forecasting accuracy of machine-learning models for close prices. 展开更多
关键词 OHLC data Structural modeling Unconstrained transformation Candlestick chart VAR VECM
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基于无参数聚类和改进支持向量机多特征融合的控制图模式识别 被引量:1
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作者 潘柏松 邱敏鹏 钱丽娟 《计算机集成制造系统》 北大核心 2025年第3期855-868,共14页
为提升智能制造中产品质量管控的准确性和及时性,提出一种基于无参数聚类和改进支持向量机多特征融合的控制图模式识别方法。采用蒙特卡洛法生成模拟数据集,考虑了质量特征均值微动的情况。将无参数聚类提取的历史数据信息特征,与统计... 为提升智能制造中产品质量管控的准确性和及时性,提出一种基于无参数聚类和改进支持向量机多特征融合的控制图模式识别方法。采用蒙特卡洛法生成模拟数据集,考虑了质量特征均值微动的情况。将无参数聚类提取的历史数据信息特征,与统计特征以及形状特征进行融合,通过交叉实验获取最优特征组合。借助白鲸算法改进支持向量机分类器,实现对控制图异常模式的准确高效识别。通过仿真实验比较了不同分类器在不同数据集复杂程度下的识别准确性和效率,结果显示,所提出的分类模型对数据集复杂程度的影响较小,即使在复杂数据集上也能保持98.63%以上的识别精度,并具备训练速度快、计算复杂度低的优点。 展开更多
关键词 控制图 模式识别 特征融合 无参数聚类
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老年下肢骨折术后尿路感染的危险因素分析及列线图预测模型构建 被引量:2
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作者 张爱东 曹雪霞 +1 位作者 陆海荣 李秀婷 《中国医刊》 2025年第1期48-52,共5页
目的分析老年下肢骨折术后尿路感染的独立危险因素,构建列线图预测模型并对其应用价值进行验证。方法回顾性选取2020年1月至2023年12月在河北医科大学第三医院行手术治疗的550例老年下肢骨折患者,根据术后是否发生尿路感染分为感染组(n=... 目的分析老年下肢骨折术后尿路感染的独立危险因素,构建列线图预测模型并对其应用价值进行验证。方法回顾性选取2020年1月至2023年12月在河北医科大学第三医院行手术治疗的550例老年下肢骨折患者,根据术后是否发生尿路感染分为感染组(n=60)与无感染组(n=490)。采用Logistic-Lasso回归分析筛选老年下肢骨折术后尿路感染的独立危险因素并构建列线图预测模型,使用受试者操作特征(ROC)曲线、校正曲线、临床决策曲线(DCA)验证该模型的价值。另选取2024年1—6月收治的113例老年下肢骨折手术患者作为外部验证样本进行外部验证。结果Logistic-Lasso回归分析显示,女性、糖尿病、低蛋白血症、手术时间、尿路结石、留置尿管时间是老年下肢骨折术后尿路感染的独立危险因素(P<0.05),据此构建列线图风险预测模型,该模型预测老年下肢骨折术后尿路感染的ROC曲线下面积(AUC)为0.809(95%CI 0.753~0.866),校准度为0.618,C-index为0.791,DCA验证显示其临床效用性较高。通过113例患者对该模型进行外部验证,结果显示AUC为0.769(95%CI 0.593~0.946),提示该模型在外部验证中仍具有较好的预测价值。结论女性、糖尿病、低蛋白血症、手术时间、尿路结石、留置尿管时间是老年下肢骨折术后尿路感染的独立危险因素,据此构建的列线图预测模型具有较好的预测价值,对早期发现老年下肢骨折术后尿路感染的高风险人群并制订针对性的围手术期管理措施具有一定指导意义。 展开更多
关键词 下肢骨折 老年人 尿路感染 危险因素 列线图预测模型
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工字钢外包薄层UHPC组合梁抗剪性价比分析 被引量:1
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作者 范学明 周晓鹏 +1 位作者 叶小杭 赵坤 《华南理工大学学报(自然科学版)》 北大核心 2025年第4期40-49,共10页
钢结构具有低碳环保、轻质高强和抗震性能卓越等多重优势,目前已经广泛应用在高层建筑、大跨度建筑和一些民用建筑;但是其固有的易发生屈曲、腐蚀以及成本较高等问题阻碍了钢结构的进一步应用。目前关于钢结构防屈曲和防腐蚀的措施会大... 钢结构具有低碳环保、轻质高强和抗震性能卓越等多重优势,目前已经广泛应用在高层建筑、大跨度建筑和一些民用建筑;但是其固有的易发生屈曲、腐蚀以及成本较高等问题阻碍了钢结构的进一步应用。目前关于钢结构防屈曲和防腐蚀的措施会大大提高结构的成本并对结构承载能力带来一定的负面影响。超高性能混凝土(UHPC)是一种基于最大堆积密度理论的新型纤维增强水泥基复合材料,具有较高的强度和较强的变形能力,并且在抗水渗透性、抗氯离子渗透性以及抗冻融性等耐久性方面有着优异的性能。如今UHPC已经广泛应用于各种结构的力学加固以及耐久加固之中。近期的研究工作表明,将钢结构与UHPC结合使用,可以有效地实现两者的优势互补,在发挥钢结构轻质高强优异特征的同时,极大地减缓了疲劳、腐蚀和失稳对钢结构的危害。该文研究了一种已经广泛投入使用的工字钢外包薄层UHPC新型组合梁,并通过Abaqus有限元软件进行仿真分析建立样本数据库。同时利用雷达图法提出组合梁抗剪性能和抗剪性价比综合评价指标,采用响应面-蒙特卡罗法,共设计4种响应面对组合梁腹板尺寸参数进行分析。分析结果表明,组合梁的抗剪性能与其性价比之间存在显著的正相关性。此外,随着工字钢腹板厚度的增加,抗剪性能和性价比先增加后降低,并在某一特定厚度处达到峰值。该研究对于优化工字钢外包UHPC组合梁的设计具有重要的工程意义。 展开更多
关键词 钢-UHPC组合梁 性价比 有限元仿真分析 雷达图法 响应面-蒙特卡罗法
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顺北裂缝型储集层油水两相相对渗透率实验
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作者 云露 汪洋 +2 位作者 曹飞 潘琳 王婋 《新疆石油地质》 北大核心 2025年第4期485-491,共7页
顺北断控裂缝型油藏非均质性强,油水运动规律复杂,传统均质模型难以准确表征相对渗透率,提出模块化裂缝网络物理模拟方法。基于天然碳酸盐岩储集层裂缝结构特征,设计不同裂缝复杂程度的天然碳酸盐岩模块物理裂缝模型,开展油水驱替实验,... 顺北断控裂缝型油藏非均质性强,油水运动规律复杂,传统均质模型难以准确表征相对渗透率,提出模块化裂缝网络物理模拟方法。基于天然碳酸盐岩储集层裂缝结构特征,设计不同裂缝复杂程度的天然碳酸盐岩模块物理裂缝模型,开展油水驱替实验,获取不同结构裂缝模型的驱替参数,计算油水两相相对渗透率,建立相渗图版,并根据顺北裂缝型储集层生产井生产情况对油水两相相对渗透率曲线分析验证,掌握油藏动态变化规律。 展开更多
关键词 顺北油田 裂缝型油藏 碳酸盐岩 相对渗透率 相渗图版 水驱效果
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航海智能仿真技术及应用研究综述
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作者 刘涛 李瀚熙 +1 位作者 尹勇 刘佳仑 《系统仿真学报》 北大核心 2025年第7期1684-1709,共26页
航海仿真通过构建船舶航行环境和行为模型,模拟不同场景下的船舶响应,用于预判复杂干扰条件下的行为特征。随着计算机图形学、虚拟现实和人工智能技术的发展,尤其是无人船技术的发展,航海仿真技术出现了新的研究内容和应用。介绍了航海... 航海仿真通过构建船舶航行环境和行为模型,模拟不同场景下的船舶响应,用于预判复杂干扰条件下的行为特征。随着计算机图形学、虚拟现实和人工智能技术的发展,尤其是无人船技术的发展,航海仿真技术出现了新的研究内容和应用。介绍了航海仿真技术的研究现状和发展趋势,从典型场景、关键技术和发展趋势三方面对航海仿真技术进行研究综述;剖析了多维电子海图、智能电子海图、船舶运动数学模型、航海模拟器等技术的发展趋势和重点;明确了以“数字孪生”和“虚实融合测试验证”技术为重要发展方向的未来航海智能仿真新趋势。关键技术攻关与产品研发是持续推进航海智能仿真技术发展的基础。该研究为航海智能仿真技术的研究与应用提供了系统参考。 展开更多
关键词 航海仿真 电子海图 船舶运动数学模型 数字孪生 虚实融合测试 航海模拟器
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