The analysis of slope earthquake stability is one of the most important research subjects in geotechnical engineering and earthquake engineering.Two different concepts of slope earthquake stability are put forward：st...The analysis of slope earthquake stability is one of the most important research subjects in geotechnical engineering and earthquake engineering.Two different concepts of slope earthquake stability are put forward：strength reserve stability and dynamic overloading stability.The first concept of slope earthquake stability has been widely accepted,and relative analysis methods are also well de-veloped;the second one,however,is seldom mentioned until now,and the failure criterion and the analysis method based on this concept are yet to be explored.What are researched are just the failure criterion and the analysis method of dynamic overloading earthquake stability.The criterion of critical earthquake peak acceleration for the dynamic overloading stability of a slope and its analysis method,the load increasing method（LIM）,are put forward.The dynamic overloading earthquake stability of a loess slope at Changshougou（长寿沟） in Baoji（宝鸡） City,Shaanxi（陕西） Province,China,is analyzed with LIM.The analysis result reveals that the dynamic overloading earthquake stability of the slope is quite high to the action of the earthquake ground motion,with exceeding probability of 10% in the next 50 years.展开更多
The ability of a pavement structure in carrying out its function reduces in line with the increase of traffic load, especially if there are overloaded heavy vehicle passing through the road. This study was done to kno...The ability of a pavement structure in carrying out its function reduces in line with the increase of traffic load, especially if there are overloaded heavy vehicle passing through the road. This study was done to know the effect of overloading vehicles on the road pavement and remaining service life of the pavement. In this study, the service life of pavement due to overloaded vehicles was analyzed using the AASHTO 1993. In Narayanghat-Mugling road the composition of traffic seems to be 83.76% heavy vehicles, 9.18% medium vehicle and 7.05% light vehicle. For the direction of Narayanghat-Mugling, the pavement service life might be reduced by 59.90% due to overloading condition, while for the opposite direction, the service life would not reduced caused by the same factor. The impact of overload conditions on the road pavement showed premature failure;that is, a condition which the damage reduced the life of roads before the design life of the road is reached. From the results, it can be concluded that overloaded vehicles on the road are very influential to the reduction in pavement service life. Therefore, it is expected that road users to comply with existing regulations in the conduct of transportation. As overloading is increasing, it has to be controlled by rules and regulations with penalty to control the overloading. So fines must be associated with intensified enforcement when considered in further strategy. Regular monitoring, inspection and enforcement are the effective ways to control overloading. Use of technology (Automatic overloading information system) may be the effective way to control the overloading.展开更多
The effect of proportional and non-proportional overloading on mode l fatigue crack growth have been studied,and the influences of crack tip plastic zone,crack tip blunting as well as crack closure were discussed.Prop...The effect of proportional and non-proportional overloading on mode l fatigue crack growth have been studied,and the influences of crack tip plastic zone,crack tip blunting as well as crack closure were discussed.Proportional(model I)overloading may cause more serious crack growth retardation than non-proportional(mixed mode)overloading.Therefore,for estimating the fatigue life of engineering structures to simplify a real overload which may of- ten be non-proportional as a proportional one is not always safe.展开更多
In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation...In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation results show that the performance of our presented mechanism in this paper is greatly improved, much better than that of the other three mechanisms： earliest deadline first （EDF）, highest value first （HVF） and highest density first （HDF）, under the same conditions of all nominal loads and task type proportions.展开更多
车载信息系统(in-vehicle information system,IVIS)通过多功能整合提升驾驶便利性,但多模态信息过载可能加剧认知负荷超额并威胁行车安全。为探究信息过载对危险驾驶行为的动态影响机制,基于刺激-有机体-反应(Stimulus-Organism-Respon...车载信息系统(in-vehicle information system,IVIS)通过多功能整合提升驾驶便利性,但多模态信息过载可能加剧认知负荷超额并威胁行车安全。为探究信息过载对危险驾驶行为的动态影响机制,基于刺激-有机体-反应(Stimulus-Organism-Response,SOR)模型引入驾驶信息需求作为调节变量,在此基础上构建视觉/听觉信息过载、认知负荷、驾驶意图与行为的理论框架。基于438名中国电动汽车用户的横断面调查数据并结合结构方程建模的数据分析表明,视觉与听觉信息过载显著正向影响认知负荷,且直接驱动不安全驾驶意图。同时,中介分析表明,信息过载可以通过认知负荷和驾驶意图间接影响驾驶行为。驾驶信息需求负向调节不安全驾驶意图向行为的转化,驾驶信息需求越高的驾驶员,越易主动抑制危险驾驶行为的外化。本研究将驾驶信息需求纳入SOR框架,揭示了多模态信息过载的差异化机制,弥补了个体差异研究的不足,也为IVIS开发方与整车制造商提供了可行的优化路径,包括抬头显示屏(head-up display,HUD)信息筛选优先级策略、认知负荷监测。展开更多
基金supported by the National Natural Science Foundation of China (No. 40902086)
文摘The analysis of slope earthquake stability is one of the most important research subjects in geotechnical engineering and earthquake engineering.Two different concepts of slope earthquake stability are put forward：strength reserve stability and dynamic overloading stability.The first concept of slope earthquake stability has been widely accepted,and relative analysis methods are also well de-veloped;the second one,however,is seldom mentioned until now,and the failure criterion and the analysis method based on this concept are yet to be explored.What are researched are just the failure criterion and the analysis method of dynamic overloading earthquake stability.The criterion of critical earthquake peak acceleration for the dynamic overloading stability of a slope and its analysis method,the load increasing method（LIM）,are put forward.The dynamic overloading earthquake stability of a loess slope at Changshougou（长寿沟） in Baoji（宝鸡） City,Shaanxi（陕西） Province,China,is analyzed with LIM.The analysis result reveals that the dynamic overloading earthquake stability of the slope is quite high to the action of the earthquake ground motion,with exceeding probability of 10% in the next 50 years.
文摘The ability of a pavement structure in carrying out its function reduces in line with the increase of traffic load, especially if there are overloaded heavy vehicle passing through the road. This study was done to know the effect of overloading vehicles on the road pavement and remaining service life of the pavement. In this study, the service life of pavement due to overloaded vehicles was analyzed using the AASHTO 1993. In Narayanghat-Mugling road the composition of traffic seems to be 83.76% heavy vehicles, 9.18% medium vehicle and 7.05% light vehicle. For the direction of Narayanghat-Mugling, the pavement service life might be reduced by 59.90% due to overloading condition, while for the opposite direction, the service life would not reduced caused by the same factor. The impact of overload conditions on the road pavement showed premature failure;that is, a condition which the damage reduced the life of roads before the design life of the road is reached. From the results, it can be concluded that overloaded vehicles on the road are very influential to the reduction in pavement service life. Therefore, it is expected that road users to comply with existing regulations in the conduct of transportation. As overloading is increasing, it has to be controlled by rules and regulations with penalty to control the overloading. So fines must be associated with intensified enforcement when considered in further strategy. Regular monitoring, inspection and enforcement are the effective ways to control overloading. Use of technology (Automatic overloading information system) may be the effective way to control the overloading.
文摘The effect of proportional and non-proportional overloading on mode l fatigue crack growth have been studied,and the influences of crack tip plastic zone,crack tip blunting as well as crack closure were discussed.Proportional(model I)overloading may cause more serious crack growth retardation than non-proportional(mixed mode)overloading.Therefore,for estimating the fatigue life of engineering structures to simplify a real overload which may of- ten be non-proportional as a proportional one is not always safe.
基金supported by the Shanghai Applied Materials Foundation (Grant No.06SA18)
文摘In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks： the soft, the hard and the imprecise tasks. The simulation results show that the performance of our presented mechanism in this paper is greatly improved, much better than that of the other three mechanisms： earliest deadline first （EDF）, highest value first （HVF） and highest density first （HDF）, under the same conditions of all nominal loads and task type proportions.
文摘车载信息系统(in-vehicle information system,IVIS)通过多功能整合提升驾驶便利性,但多模态信息过载可能加剧认知负荷超额并威胁行车安全。为探究信息过载对危险驾驶行为的动态影响机制,基于刺激-有机体-反应(Stimulus-Organism-Response,SOR)模型引入驾驶信息需求作为调节变量,在此基础上构建视觉/听觉信息过载、认知负荷、驾驶意图与行为的理论框架。基于438名中国电动汽车用户的横断面调查数据并结合结构方程建模的数据分析表明,视觉与听觉信息过载显著正向影响认知负荷,且直接驱动不安全驾驶意图。同时,中介分析表明,信息过载可以通过认知负荷和驾驶意图间接影响驾驶行为。驾驶信息需求负向调节不安全驾驶意图向行为的转化,驾驶信息需求越高的驾驶员,越易主动抑制危险驾驶行为的外化。本研究将驾驶信息需求纳入SOR框架,揭示了多模态信息过载的差异化机制,弥补了个体差异研究的不足,也为IVIS开发方与整车制造商提供了可行的优化路径,包括抬头显示屏(head-up display,HUD)信息筛选优先级策略、认知负荷监测。
文摘为应对新能源机组随机波动导致的外送断面过载约束复杂多变的问题,提出一种计及新能源特性的自动发电控制(automatic generation control,AGC)断面越限预防和校正控制方法。首先,提出计及新能源特性、涵盖主站-厂站-机组三级架构的AGC断面功率越限控制模型;其次,基于潮流转移比矩阵快速计算N-1故障后线路负载率矩阵,快速评估AGC断面功率越限风险;最后,推导线路N-1故障后负载率相对发电机组出力的灵敏度,明确不同机组功率调节对断面功率的差异化影响,以新能源机组消纳最大、AGC机组调节量最小为控制原则,提出基于线路负载率灵敏度的AGC断面越限校正控制方法。在PSD Power Tools中搭建实际电网仿真算例验证了所提方法的正确性和有效性。
