Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be...Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.展开更多
The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and e...The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and economic development. A new performance-based seismic design criterion that is composed of three components is presented in this paper. It can not only effectively control the economic losses and casualty, but also ensure the building's function in proper operation during earthquakes. The three components are: classification of seismic design for buildings, determination of seismic design intensity and/or seismic design ground motion for controlling seismic economic losses and casualties, and determination of the importance factors in terms of service periods of buildings. For controlling the seismic human losses, the idea of socially acceptable casualty level is presented and the 'Optimal Economic Decision Model' and 'Optimal Safe Decision Model' are established. Finally, a new method is recommended for calculating the importance factors of structures by adjusting structures service period on the base of more important structure with longer service period than the conventional ones. Therefore, the more important structure with longer service periods will be designed for higher seismic loads, in case the exceedance probability of seismic hazard in different service period is same.展开更多
为提高智能软开关(soft open point, SOP)接入配电网的综合效能,本文提出了一种计及重要用户失负荷风险的多端SOP优化配置方法。首先,采用数据包络分析和逆向数据包络分析方法建立了重要用户停电损失模型,并采用马尔可夫方法建立了SOP...为提高智能软开关(soft open point, SOP)接入配电网的综合效能,本文提出了一种计及重要用户失负荷风险的多端SOP优化配置方法。首先,采用数据包络分析和逆向数据包络分析方法建立了重要用户停电损失模型,并采用马尔可夫方法建立了SOP多状态可靠性模型。然后提出了重要用户转供优先级指标和故障恢复策略,并基于快速失负荷风险计算公式,建立了计及重要用户失负荷风险的SOP位置和容量双层规划模型,最后提出了多目标进化算法和锥规划相结合的混合优化算法对模型进行求解。算例仿真结果表明,所提模型可以降低SOP配置的年综合成本和重要用户停电损失;相比传统规划方法,解决了因配置的SOP容量较低而无法展现其不间断转供能力和故障恢复能力的问题;所提快速失负荷风险计算方法相比传统方法更高效。研究结果可为SOP在配电网中的实际应用提供理论和技术参考。展开更多
以山西省为研究对象,基于中国土壤流失方程(Chinese Soil Loss Equation)、遥感和GIS空间分析技术,通过合理选择CSLE中各土壤侵蚀因子的数据来源和计算方法,依据《土壤侵蚀分类分级标准》对2000—2010年山西省省市县3级行政体系的土壤...以山西省为研究对象,基于中国土壤流失方程(Chinese Soil Loss Equation)、遥感和GIS空间分析技术,通过合理选择CSLE中各土壤侵蚀因子的数据来源和计算方法,依据《土壤侵蚀分类分级标准》对2000—2010年山西省省市县3级行政体系的土壤侵蚀风险情况进行了分析,并运用地理加权回归分析方法,计算了土壤侵蚀模型中各因子对侵蚀量的贡献率。结果表明:(1)山西省年均土壤侵蚀总量达3.58×108t,平均土壤侵蚀模数为2 287t/(km^2·a)。若以土壤侵蚀强度高于微度为侵蚀风险地区,则山西省存在水土流失风险的地区约占全省面积的48%;(2)11个地级市中,轻度侵蚀城市依次为长治、晋中、晋城、太原、大同、运城和朔州,中度侵蚀依次为吕梁、临汾、阳泉和忻州。106个县级行政区中,微度侵蚀的县有14个,轻度侵蚀的县有61个,中度侵蚀的县有27个,强度侵蚀的县有4个;(3)地形因子对水力侵蚀引起的土壤侵蚀模数具有最高的贡献率,而因子取得最值的位置并不与贡献率最值的位置相一致。展开更多
目的:探讨退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)后路长节段固定融合术中大量失血的相关危险因素。方法:收集173例在我院行后路长节段(≥4节段)固定融合术的DLS患者的临床资料,根据术中失血量分为大量失血组(失血分数≥30%...目的:探讨退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)后路长节段固定融合术中大量失血的相关危险因素。方法:收集173例在我院行后路长节段(≥4节段)固定融合术的DLS患者的临床资料,根据术中失血量分为大量失血组(失血分数≥30%)和非大量失血组(失血分数<30%)。比较两组患者术前、术中及术后相关资料,患者人口学资料包括性别、年龄、体重指数(body mass index, BMI)、吸烟史、饮酒史、术前骨质状况、术前美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级等;影像学资料包括术前Cobb角、冠状面和矢状面失衡情况、顶椎偏移距离(apical vertebral translation,AVT)、腰椎前凸角(lumbar lordosis,LL)、Cobb角和LL矫正值;手术相关资料包括手术时间、固定节段、减压节段、椎间融合节段、术中截骨及截骨级别、固定骶骨、术中使用氨甲环酸(tranexamic acid,TXA)情况等、术中失血量、术中及术后输血资料和医疗费用。采用单因素分析及多因素Logistics回归分析导致术中大量失血的危险因素。结果:67例患者纳入大量失血组,106例患者纳入非大量失血组,单因素分析结果显示大量失血组相较非大量失血组,BMI较小(P=0.046)、术前Cobb角较大(P<0.001)、AVT较大(P=0.002)、Cobb角矫正值(P<0.001)较大、固定节段较多(P<0.001)、椎间融合节段较多(P=0.043)、截骨级别较高(P<0.001)、术中TXA使用比例更小(P=0.046),大量失血组在围手术期输血量(P=0.015)、输血率(P=0.035)、术后住院时间(P=0.035)、住院费用(P=0.023)显著高于非大量失血组。多因素Logistics二元回归分析结果显示BMI每增加1kg/m^2,术中大量失血风险降低9.3%;术中Cobb角矫正值每增加1°、固定节段每增加1个节段,术中大量失血风险分别增加5.9%、58.9%;椎间融合节段每增加一个节段,术中大量失血风险增加1.174倍;术中行三级及以上截骨使术中大量失血风险增加9.262倍;术中使用TXA使术中大量失血风险降低71.2%。结论:BMI较小,术前Cobb角和AVT较大,Cobb角矫正值增加、固定节段增加、椎间融合节段增加、术中截骨、截骨分级高、术中未使用TXA等因素是导致DLS患者长节段固定融合手术术中大量失血的潜在危险因素,其中,BMI较小、Cobb角矫正值增加、固定节段增加、椎间融合节段增加、行3级及以上截骨、术中未使用TXA是导致术中大量失血的独立危险因素。展开更多
基金Project(2011CB013804) supported by the National Basic Research Program of ChinaProject(50925828) supported by the National Natural Science Funds for Distinguished Young Scholars of China
文摘Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.
基金Chinese National Natural Science Foundation with the grant No.59895410the China Basic Research and Development Project:the Mechanism and Prediction of the Strong Earthquake of the Continental under the Grant No.95130603
文摘The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and economic development. A new performance-based seismic design criterion that is composed of three components is presented in this paper. It can not only effectively control the economic losses and casualty, but also ensure the building's function in proper operation during earthquakes. The three components are: classification of seismic design for buildings, determination of seismic design intensity and/or seismic design ground motion for controlling seismic economic losses and casualties, and determination of the importance factors in terms of service periods of buildings. For controlling the seismic human losses, the idea of socially acceptable casualty level is presented and the 'Optimal Economic Decision Model' and 'Optimal Safe Decision Model' are established. Finally, a new method is recommended for calculating the importance factors of structures by adjusting structures service period on the base of more important structure with longer service period than the conventional ones. Therefore, the more important structure with longer service periods will be designed for higher seismic loads, in case the exceedance probability of seismic hazard in different service period is same.
文摘为提高智能软开关(soft open point, SOP)接入配电网的综合效能,本文提出了一种计及重要用户失负荷风险的多端SOP优化配置方法。首先,采用数据包络分析和逆向数据包络分析方法建立了重要用户停电损失模型,并采用马尔可夫方法建立了SOP多状态可靠性模型。然后提出了重要用户转供优先级指标和故障恢复策略,并基于快速失负荷风险计算公式,建立了计及重要用户失负荷风险的SOP位置和容量双层规划模型,最后提出了多目标进化算法和锥规划相结合的混合优化算法对模型进行求解。算例仿真结果表明,所提模型可以降低SOP配置的年综合成本和重要用户停电损失;相比传统规划方法,解决了因配置的SOP容量较低而无法展现其不间断转供能力和故障恢复能力的问题;所提快速失负荷风险计算方法相比传统方法更高效。研究结果可为SOP在配电网中的实际应用提供理论和技术参考。
文摘以山西省为研究对象,基于中国土壤流失方程(Chinese Soil Loss Equation)、遥感和GIS空间分析技术,通过合理选择CSLE中各土壤侵蚀因子的数据来源和计算方法,依据《土壤侵蚀分类分级标准》对2000—2010年山西省省市县3级行政体系的土壤侵蚀风险情况进行了分析,并运用地理加权回归分析方法,计算了土壤侵蚀模型中各因子对侵蚀量的贡献率。结果表明:(1)山西省年均土壤侵蚀总量达3.58×108t,平均土壤侵蚀模数为2 287t/(km^2·a)。若以土壤侵蚀强度高于微度为侵蚀风险地区,则山西省存在水土流失风险的地区约占全省面积的48%;(2)11个地级市中,轻度侵蚀城市依次为长治、晋中、晋城、太原、大同、运城和朔州,中度侵蚀依次为吕梁、临汾、阳泉和忻州。106个县级行政区中,微度侵蚀的县有14个,轻度侵蚀的县有61个,中度侵蚀的县有27个,强度侵蚀的县有4个;(3)地形因子对水力侵蚀引起的土壤侵蚀模数具有最高的贡献率,而因子取得最值的位置并不与贡献率最值的位置相一致。
文摘目的:探讨退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)后路长节段固定融合术中大量失血的相关危险因素。方法:收集173例在我院行后路长节段(≥4节段)固定融合术的DLS患者的临床资料,根据术中失血量分为大量失血组(失血分数≥30%)和非大量失血组(失血分数<30%)。比较两组患者术前、术中及术后相关资料,患者人口学资料包括性别、年龄、体重指数(body mass index, BMI)、吸烟史、饮酒史、术前骨质状况、术前美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级等;影像学资料包括术前Cobb角、冠状面和矢状面失衡情况、顶椎偏移距离(apical vertebral translation,AVT)、腰椎前凸角(lumbar lordosis,LL)、Cobb角和LL矫正值;手术相关资料包括手术时间、固定节段、减压节段、椎间融合节段、术中截骨及截骨级别、固定骶骨、术中使用氨甲环酸(tranexamic acid,TXA)情况等、术中失血量、术中及术后输血资料和医疗费用。采用单因素分析及多因素Logistics回归分析导致术中大量失血的危险因素。结果:67例患者纳入大量失血组,106例患者纳入非大量失血组,单因素分析结果显示大量失血组相较非大量失血组,BMI较小(P=0.046)、术前Cobb角较大(P<0.001)、AVT较大(P=0.002)、Cobb角矫正值(P<0.001)较大、固定节段较多(P<0.001)、椎间融合节段较多(P=0.043)、截骨级别较高(P<0.001)、术中TXA使用比例更小(P=0.046),大量失血组在围手术期输血量(P=0.015)、输血率(P=0.035)、术后住院时间(P=0.035)、住院费用(P=0.023)显著高于非大量失血组。多因素Logistics二元回归分析结果显示BMI每增加1kg/m^2,术中大量失血风险降低9.3%;术中Cobb角矫正值每增加1°、固定节段每增加1个节段,术中大量失血风险分别增加5.9%、58.9%;椎间融合节段每增加一个节段,术中大量失血风险增加1.174倍;术中行三级及以上截骨使术中大量失血风险增加9.262倍;术中使用TXA使术中大量失血风险降低71.2%。结论:BMI较小,术前Cobb角和AVT较大,Cobb角矫正值增加、固定节段增加、椎间融合节段增加、术中截骨、截骨分级高、术中未使用TXA等因素是导致DLS患者长节段固定融合手术术中大量失血的潜在危险因素,其中,BMI较小、Cobb角矫正值增加、固定节段增加、椎间融合节段增加、行3级及以上截骨、术中未使用TXA是导致术中大量失血的独立危险因素。
