我国股市波动的ARCH类模型分析

股票价格的频繁波动是股票市场最明显的特征之一。 ARCH类模型可以成功地预测金融资产收益率的方差。通过对我国股价指数的统计描述 ,表明我国金融资产收益率存在自回归条件异方差特征 ,并表现出非正态性。利用 ARCH类模型对深圳成份指数的波动进行拟合 ,结果表明 。

Recent Construction Technology Innovations and Practices for Large-Span Arch Bridges in China

Arch bridges provide significant technical and economic benefits under suitable conditions.In particular,concrete-filled steel tubular(CFST)arch bridges and steel-reinforced concrete(SRC)arch bridges are two types of arch bridges that have gained great economic competitiveness and span growth potential due to advancements in construction technology,engineering materials,and construction equipment over the past 30 years.Under the leadership of the author,two record-breaking arch bridges—that is,the Pingnan Third Bridge(a CFST arch bridge),with a span of 560 m,and the Tian’e Longtan Bridge(an SRC arch bridge),with a span of 600 m—have been built in the past five years,embodying great technological breakthroughs in the construction of these two types of arch bridges.This paper takes these two arch bridges as examples to systematically summarize the latest technological innovations and practices in the construction of CFST arch bridges and SRC arch bridges in China.The technological innovations of CFST arch bridges include cable-stayed fastening-hanging cantilevered assembly methods,new in-tube concrete materials,in-tube concrete pouring techniques,a novel thrust abutment foundation for nonrocky terrain,and measures to reduce the quantity of temporary facilities.The technological innovations of SRC arch bridges involve arch skeleton stiffness selection,the development of encasing concrete materials,encasing concrete pouring,arch rib stress mitigation,and longitudinal reinforcement optimization.To conclude,future research focuses and development directions for these two types of arch bridges are proposed.

ESMO2023:恩扎卢胺联合雄激素剥夺治疗对比安慰剂联合雄激素剥夺治疗在中国转移性激素敏感性前列腺癌患者中的疗效和安全性(中国ARCHES)

2019年发表的全球ARCHES试验(NCT02677896)结果显示,与安慰剂(placebo,PBO)+雄激素剥夺治疗(androgen deprivation therapy,ADT)相比,恩扎卢胺+ADT延长了转移性激素敏感性前列腺癌(metastatic hormone-sensitive prostate cancer,mHSPC)患者的总生存期和放射影像学无进展生存期(radiographic progression-free survival,rPFS)^([1])。然而,该试验无中国患者入组。欧洲肿瘤内科学会(European Society for Medical Oncology,ESMO)2023年会议报道了中国ARCHES研究(NCT04076059)的初步结果,这是一项评估恩扎卢胺+ADTvs.PBO+ADT在中国m HSPC患者中的疗效和安全性的多中心、随机、双盲、PBO对照的Ⅲ期试验^([2])。

Numerical Simulation Analysis of Welded Joints in Arch Ribs of Large Span Steel Pipe Arch Bridges

In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.

中国汽油价格波动基于ARCH模型的分析研究

本文采用ARCH模型,并使用Eviews10统计学软件,利用2014年到2024年近11年的92号汽油价格,分析中国汽油市场价格的波动性。通过分析北京、上海、广州三个地区的92号汽油价格,表明中国汽油价格残差序列具有明显的“尖峰厚尾”特征,也具有显著的波动性特性。同时也印证了ARCH模型能够很好地描述中国汽油价格市场的波动性特性。本文最后根据实证分析结果,对中国应积极应对国际油价的变化,提出可操作性建议。

基于ARMA-EGARCH-M模型的沪深股市波动性分析

文章讨论了ARCH模型族的拟合波动性的优缺点,建立ARMA-EGARCH-M模型,简要说明了此模型的优点;以2000年1月11日-2006年3月15日上证综指和深证成指收盘价为样本,对我国沪深股市收益率分布用ARMA-EGARCH-M模型进行拟合分析,结果表明该模型能更有效地拟合我国沪深股市的波动性;最后解释实证结果和分析了我国股市的行为。

ARCH类模型研究及其在沪市A股中的应用

本文主要介绍ARCH(AutoregressiveConditionalHeteroskedasticity)模型、GARCH模型和E GARCH模型 ,分析这些模型的特点和适用范围 ,并在模型中引入t分布取代正态分布假设 ,最后利用这些模型对上证指数进行了实证分析。

基于比较视角的我国股票市场波动ARCH效应研究

我国同期的主板市场不存在ARCH效应,中小板市场存在弱势ARCH效应,创业板市场存在明显的ARCH效应;GARCH(1,2)模型能较好地刻画中小板指数,GARCH(1,1)模型能较好地刻画创业板指数;EGARCH(1,2)能较好地刻画中小板市场波动的非对称性,EGARCH(1,1)模型能较好地刻画创业板市场波动的非对称性;GARCH(1,2)-M模型不能有效刻画中小板指数,GARCH(1,1)-M也不能有效刻画创业板指数,表明中小板市场及创业板市场日收益序列对风险溢价的敏感性不强。

我国创业板市场波动的ARCH效应研究

相对于主板市场而言,创业板上市公司具有明显的高科技、高成长、波动性大等特点。ARCH类模型较好地拟合了资本市场中资产收益的"尖峰厚尾"、"波动率集聚"等一系列的特征,广泛应用于资产收益与波动率的分析。选取2010/6/1—2012/5/31的创业板指数日收盘价,运用GARCH族模型对我国创业板指数的日收益及波动率进行研究的结果表明,我国创业板市场存在明显的ARCH效应,且GARCH(1,1)、EGARCH(1,1)模型都能较好地拟合,而GARCH(1,1)-M在验证指数波动对收益影响却不显著,表明创业板市场收益与波动关联性不强。

Health diagnosis of ultrahigh arch dam performance using heterogeneous spatial panel vector model

Currently,more than ten ultrahigh arch dams have been constructed or are being constructed in China.Safety control is essential to long-term operation of these dams.This study employed the flexibility coefficient and plastic complementary energy norm to assess the structural safety of arch dams.A comprehensive analysis was conducted,focusing on differences among conventional methods in characterizing the structural behavior of the Xiaowan arch dam in China.Subsequently,the spatiotemporal characteristics of the measured performance of the Xiaowan dam were explored,including periodicity,convergence,and time-effect characteristics.These findings revealed the governing mechanism of main factors.Furthermore,a heterogeneous spatial panel vector model was developed,considering both common factors and specific factors affecting the safety and performance of arch dams.This model aims to comprehensively illustrate spatial heterogeneity between the entire structure and local regions,introducing a specific effect quantity to characterize local deformation differences.Ultimately,the proposed model was applied to the Xiaowan arch dam,accurately quantifying the spatiotemporal heterogeneity of dam performance.Additionally,the spatiotemporal distri-bution characteristics of environmental load effects on different parts of the dam were reasonably interpreted.Validation of the model prediction enhances its credibility,leading to the formulation of health diagnosis criteria for future long-term operation of the Xiaowan dam.The findings not only enhance the predictive ability and timely control of ultrahigh arch dams'performance but also provide a crucial basis for assessing the effectiveness of engineering treatment measures.

深证成指周收益率波动及预测实证研究——基于ARCH模型

文章以1996—2012年深证成指(399001)周收盘价为对象,就我国股市波动情况进行实证研究。研究结果表明,我国深成指周收益率序列不存在自相关;对比GARCH(1,1)模型和GARCH-M(1,1)模型,不含常数项的GARCH-M(1,1)模型优于捕捉深成指周收益率的波动性。文章最后对其波动性进行了预测分析。

汇率波动非对称效应的计量检验—基于非对称ARCH类模型

本文利用非对称ARCH类模型对1994年1月1日至2007年8月24日的人民币/美元的日汇率序列的波动特性进行了计量检验,检验结果表明在此期间汇率序列的波动存在显著的条件异方差性和波动过程的非对称性,利空消息引起的汇率波动大于利好消息引起的汇率波动。

The Comparison of Different Degree of Convexity and 3D Modeling of Involute Hyperbolic Arch Dam

Because of good quality of compressive resistance, the hyperbolic arch dam is being increasingly applied to engineering projects. In order to satisfy the needs of compressive resistance under the conditions of high water pressure, a stress analysis is required for the dam. During the stress analysis process however, due to the complexity of the three-dimensional modeling, it is very hard to form a model. Therefore, the stress analysis process is a barrier for the arch dam. In this article, based on the research of the new line-type arch dam, a mathematical model in different degree of convexity conditions of the dam is established; using the C ＋ ＋ language program, a computer three-dimensional model simulation is realized on AutoCAD. The accurate three-dimensional model is providing a finite element optimization design of the involute hyperbolic arch dam for the next step.

A Nonlinear Explicit Model of A Non-Circular Subsea Tunnel-Liner System with An FGM Inverted Arch Under Mechanical Loading and Fire Fields

This paper proposes an explicit scheme to analyze the failure of a subsea polyhedral tunnel-liner system with an inverted arch under mechanical loading and fire fields.The thin-walled liner is made of Functionally Graded Materials(FGMs),which may improve the stability behavior of the tunnel-liner system.Hydrostatic pressure is inevitable in the liner since underground water may penetrate the cracks of the tunnel,and reach the outer surface of the liner.In addition,an elevated temperature loading is taken into account,considering that fire may occur in the tunnel-liner system.Under the combination of mechanical loading and thermal loading,the liner deforms into a single-lobe shape,which is depicted by a trigonometric function.The total potential energy is expressed quantitatively after the energy approach and thin-walled shell theory are used.The minimum potential energy is obtained when the critical buckling occurs.The critical buckling pressure is calculated,which considers the effect of the thermal field.The present analytical prediction is subsequently compared precisely with other closed-form solutions.Finally,the effects of several parameters,such as the geometric shapes,temperature variations,and volume fraction indices,are discussed to further survey the buckling performance of the nonlinear buckling of an FGM polyhedral liner with an inverted arch.One may address a polyhedral liner with fewer polyhedral sides,and a lower volume fraction index is recommended to rehabilitate cracked tunnels in engineering applications.

Effects of comprehensive nursing with cognitive behavioral therapy in orthodontic osteodilated arch treatment

BACKGROUND This work explored the effects of cognitive behavior therapy(CBT)-based comprehensive nursing intervention(CNI)mode in arch expansion to treat patients with orthodontic osteodilated arch(OOA).AIM To explore the application effect of CBT-based CNI model in orthodontic expansion arch treatment.METHODS Using convenient sampling method,81 patients with OOA were selected and rolled into a control group(Ctrl group,40 cases)and an observation group(Obs group,41 cases).During the treatment,patients in the Ctrl group received routine nursing intervention mode,and the those in the Obs group received CBT mode on the basis of this.Before and after intervention,the incidence of oral mucositis,the mastery rate of correct arch expansion method,self-rating anxiety scale score,soft scale index,and plaque index were compared for patients in different groups.In addition,satisfaction and complications were comparatively analyzed.RESULTS Incidence of oral mucositis in the Obs group was lower(14.6%vs 38.5%),and the mastery rate of correct arch expansion method was obviously higher(90.2%vs 55.0%)was obviously higher(all P<0.05).Meanwhile,the soft scale index and plaque index in the Obs group were much lower(P<0.05).The compliance(90.24%)and satisfaction(95.12%)in the Obs group were greatly higher(P<0.05).CONCLUSION The CBT-based CNI mode greatly improved the mastery rate of correct arch expansion method during arch expansion in treating patients with OOA and enhanced the therapeutic effect of arch expansion and the oral health of patients,improving the patient compliance.

Prediction model of surrounding rock deformation in doublecontinuous-arch tunnel based on the ABC-WNN

Purpose–The wavelet neural network(WNN)has the drawbacks of slow convergence speed and easy falling into local optima in data prediction.Although the artificial bee colony(ABC)algorithm has strong global optimization ability and fast convergence speed,it also has the drawbacks of slow speed while finding the optimal solution and weak optimization ability in the later stage.Design/methodology/approach–This article uses an ABC algorithm to optimize the WNN and establishes an ABC-WNN analysis model.Based on the example of the Jinan Yuhan underground tunnel project,the deformation of the surrounding rock of the double-arch tunnel crossing the fault fracture zone is predicted and analyzed,and the analysis results are compared with the actual detection amount.Findings–The comparison results show that the predicted values of the ABC-WNN model have a high degree of fitting with the actual engineering data,with a maximum relative error of only 4.73%.On this basis,the results show that the statistical features of ABC-WNN are the lowest,with the errors at 0.566 and 0.573,compared with the single back propagation(BP)neural network model and WNN model.Therefore,it can be derived that the ABC-WNN model has higher prediction accuracy,better computational stability and faster convergence speed for deformation.Originality/value–This article uses firstly the ABC-WNN for the deformation analysis of double-arch tunnels.This attempt laid the foundation for artificial intelligence prediction in deformation analysis of multiarch tunnels and small clearance tunnels.It can provide a new and effective way for deformation prediction in similar projects.

基于ARMA-GARCH模型的超短期风功率预测研究

风功率预测对提高电能质量和电力系统的安全运行具有重要意义。基于时间序列的方法,对内蒙古赤峰地区某风场的风功率数据进行了超短期预测,通过对数据平稳性检验的结果,建立了时间序列的ARMA模型,利用拉格朗日乘子检验的方法,检验ARMA模型具有ARCH效应,并建立适合的ARMA-GARCH模型。结论通过对比ARMA模型,ARMA-ARCH模型和ARMA-GARCH模型的风功率预测精度可知,在解决数据的残差序列异方差函数具有长期相关性时,ARMA-GARCH模型能够有效的提高预测精度。

BP算法和对称ARCH类模型对股市波动性预测的实证比较

利用我国深圳股票市场的实际数据,建立了相应的BP算法网络预测模型和ARCH(1),GARCH(1,1)预测模型,分别用来对深成指数每个周末收盘价的波动性进行预测．研究表明,BP算法对样本外观测值的上凸曲线拟合得较好,对下凸曲线的拟合效果较差;ARCH(1)和GARCH(1,1)则反之,其预测曲线对样本外观测值的下凸曲线拟合效果都较好,但对上凸曲线的拟合效果都较差．通过采用6种常用的预测误差统计量:平均误差、平均绝对误差、均方根误差、平均绝对比率误差、Akaike信息准则、Baves信息准则对样本外数据的预测结果进行检验,BP算法的预测效果最好,ARCH(1)模型次之,GARcH(1,1)模型偏差．

基于GED-GARCH类模型的我国原油现货市场波动性的研究

选取2005年1月3日至2011年7月28日大庆原油现货日平均价格,以广义误差分布代替正态分布以反映金融资产的尖峰厚尾性,建立了GARCH(1,1)、GARCH-M、TARCH(1,1)、EGARCH(1,1)等多个模型,实证研究了我国原油现货市场收益率的波动特征。实证结果表明:大庆原油现货价格收益率具有波动集聚性;大庆原油现货市场收益率存在ARCH效应,在拟合大庆原油现货市场的ARCH效应时,GARCH(1,1)能较GARCH-M更好地消除ARCH效应;大庆原油现货市场存在明显的杠杆效应,利空消息对大庆原油市场的冲击是利好消息对原油市场的冲击的1.66倍,在描述大庆原油现货市场杠杆效应时,EGARCH(1,1)模型比TARCH(1,1)模型拟合效果好。