To reduce the risk of traffic accidents significantly caused by the speeding behavior of electric bicycles,this study focuses on the Beijing Yizhuang Economic and Tech-nological Development Zone.This work relies on hi...To reduce the risk of traffic accidents significantly caused by the speeding behavior of electric bicycles,this study focuses on the Beijing Yizhuang Economic and Tech-nological Development Zone.This work relies on high-precision shared electric bicycle Global Positioning System trajectory data,integrating a spatiotemporal analysis model and geographic information system(GIS)technol-ogy to explore the spatial and temporal variability law and formation mechanism of speeding behavior.Through data preprocessing,speeding events are identified,and weekday features are extracted.Four periods are identified:morning peak,midday minipeak,evening peak,and nighttime flat peak.Using the GIS platform,global spatial autocorrela-tion and local clustering analysis are conducted to identify the spatial clustering characteristics of speeding behaviors and hotspot areas.The coldspot and hotspot patterns of speeding events and the dynamic trajectories of their evolu-tion are analyzed using spatiotemporal cube technology.The results show that speeding behaviors are strongly corre-lated with the commuting peak in time and spatially concen-trated in the intersections of urban main roads,the periphery of commercial complexes,and industrial parks,with a dif-fusion tendency.The results of this study provide novel in-sights into the research and analysis of the spatial and tempo-ral characteristics of speeding risk behaviors of electric bi-cycles and effective technical support for nonmotorized traf-fic safety management.展开更多
Multi-frictional disks are employed to transmit the torque in speeding wetclutch, and the oil thickness within frictional disks could be adjusted for practical outputspeeding. As oil combined with alpha-hydrocarbon or...Multi-frictional disks are employed to transmit the torque in speeding wetclutch, and the oil thickness within frictional disks could be adjusted for practical outputspeeding. As oil combined with alpha-hydrocarbon or polyester is getting widely used as lubricantand the speeding wet clutch works within hydrodynamic lubrication, mixture lubrication, boundarylubrication and contact situation, established the thermal analysis model for investigating thebehavior of frictional disks in speeding wet clutch, which covers the power-law fluid model,Patir-Cheng average flow model, GT asperity contact model, oil film inertia and heat effects, meanenergy equation, and heat conduction equation. The formulas in the model are deduced. The numeralcalculation and analysis for hydrodynamic lubrication and mixture lubrication are executed.Relationships and variations among transmitting torque, mean push pressure, output speed, and loadare presented. Thermal effect should be considered during the hydrodynamic lubrication and largertransmitting torque makes earlier entrance to mixture lubrication.展开更多
China is the main silk producer in the world, whose RSS (Raw Silk Standard)is widely approved in international trade. After entering WTO, China needs to revise the RSSaccording to the changes of silk industry and deve...China is the main silk producer in the world, whose RSS (Raw Silk Standard)is widely approved in international trade. After entering WTO, China needs to revise the RSSaccording to the changes of silk industry and develop advanced electronic testing system and improvetesting means, so as to promote the internationlization of the RSS. 1. The international standingof Chinese silk The silk consisting of 18 amino acids has the similar protein structure to people'sskin. It is enjoyed by most people for it' s comfortable, magnificent and noble features and ispraised to be the second skin for its unique effects on health and adjusting the body water. In the21st century, silk is the main international fashion as the representative of green products.展开更多
In recent years, the subcontracting production for foreign trade of the Xi’an Aviation Engine Company (XAEC), a foreign trade production base of China, has achieved rapid development. In 1994, the company’s export e...In recent years, the subcontracting production for foreign trade of the Xi’an Aviation Engine Company (XAEC), a foreign trade production base of China, has achieved rapid development. In 1994, the company’s export earnings from foreign trade made a breakthrough at US$11 million, and it was commended by the State Economic展开更多
To introduce foreign capital for the municipal highway construction is a great measure to meet the development of the socialist market economy and to reform the investment system for the municipal highway construction...To introduce foreign capital for the municipal highway construction is a great measure to meet the development of the socialist market economy and to reform the investment system for the municipal highway construction. The aim of the reform lies in taking the construction and management of the municipal highway facilities as an industry to operate, widening the investment channel of the municipal highway construction and gradually forming a benign cycle of investment-construc-展开更多
According to customs statistics, China’s exports of machinery and electric products in 1996 were worth US$ 48.21 billion, an increase of 9.9 percent over the preceding year, and 8.4 percent higher than the growth rat...According to customs statistics, China’s exports of machinery and electric products in 1996 were worth US$ 48.21 billion, an increase of 9.9 percent over the preceding year, and 8.4 percent higher than the growth rate of the nation’s total exports. The proportion of machinery and electric product exports in the nation’s total foreign trade volume\ increased from 29.5 percent in 1995 to 31.9 percent in 1996, a growth at 2.4 percent.展开更多
Housing isone of the necessities of humansfor existence and development.The Chinese government hasalways attached great importanceto housing construction;especially in recent years,thepriority development of housingco...Housing isone of the necessities of humansfor existence and development.The Chinese government hasalways attached great importanceto housing construction;especially in recent years,thepriority development of housingconstruction has been seen inthe real estate and propertiesindustry.Hou Jie,Minister ofConstruction,not long ago wrotean article summarizing theachievements made in this sectorand drawing a blueprint forspeedup of housing constructionand the improvement of livingconditions in the future.It willprovide a vast vista for thedevelopment of China’s buildingindustry and its internationalcooperation.展开更多
High-speed railways have the merits of high speed, high transport capacity, low consumption of energy, less pollution, less occupation of land, and greater safety. The development of high-speed railways is suitable fo...High-speed railways have the merits of high speed, high transport capacity, low consumption of energy, less pollution, less occupation of land, and greater safety. The development of high-speed railways is suitable for the national conditions in China.The authors suggest that, with the Hu-Ning (Shanghai-Nanjing) section of the Jing-Hu (Beijing-Shanghai) Railway as the starting point, a high-speed dedicated passenger railway line be built to realize the separate transportation of passengers and goods, thus easing the strain on transport in East China, accumulating experience for the future development of high-speed railways, and bringing along the development of high and new technology industries.展开更多
This paper discusses the urgency to further develop China’s space technological industry;analyzes the gaps between China and other advanced countries in space industry,including technological level,development scale,...This paper discusses the urgency to further develop China’s space technological industry;analyzes the gaps between China and other advanced countries in space industry,including technological level,development scale,application scope and investment;describes the current severe situation that the China’s space industry is faced with and proposes the overall objective,guiding principles and major tasks of China’s space technological sector in the Ninth-Five Year Plan and the coming decade.Finally,it proposes some policies and effective measures to speed up the development of China’s space industry to meet the challenge in the 21st century.展开更多
Speeding in a work zone needs to be tackled effectively to enhance work zone safety. This study evaluates the influence of three different work zone signs—speed photo enforced signs, dynamic speed display signs and r...Speeding in a work zone needs to be tackled effectively to enhance work zone safety. This study evaluates the influence of three different work zone signs—speed photo enforced signs, dynamic speed display signs and reduced speed limit signs—on driver speeding behavior using a medium-fidelity driving simulator. The speed photo enforced and reduced speed limit signs were placed at intervals before the start of the work zone and in the work zone. A virtual work zone network was built to replicate the Baltimore–Washington Parkway(MD-295). A total of 66 participants from different socioeconomic backgrounds participated in 264 driving simulation sessions. The speeds were measured over four phases: initial speed area, sign visible area, sign readable area and post sign area. An analysis of variance and post hoc analysis showed that the speed photo enforced sign was the most effective of the three signs. The second speed photo enforced sign within the work zone was more effective at reducing speed than the sign before the start of the work zone, especially in the post sign area. It was observed that female participants tend to slow down more when encountering a speed photo enforcement sign.展开更多
Over-speeding is a pivotal factor in fatal traffic crashes globally,necessitating robust speed management strategies to augment road safety.In 2021,the National Highway Traffic Safety Administration reported over 1200...Over-speeding is a pivotal factor in fatal traffic crashes globally,necessitating robust speed management strategies to augment road safety.In 2021,the National Highway Traffic Safety Administration reported over 12000 speed-related fatalities in the United States alone.Previous studies aggregated over-speeding tendencies;however,the extent of over-speeding has a significant implication on the crash outcome.This study delves into the prevalence and magnitude of over-speeding in various scenarios,utilizing data from traffic cameras in Edmonton,Canada,and employing a negative binomial statistical model for analysis.The model elucidates the significance and likelihood of over-speeding tenden-cies by incorporating temporal and built environment variables,i.e.,year,month,number of lanes,dwelling unit types,school-related,and open green space.Study results indicated that the aggregation of the over-speeding data tends to underestimate the influence of var-ious factors.Notably,the estimated impact of the posted speed limit for the disaggregated models is up to over two times that for the aggregated model.Further,the summer months exhibit a roughly 25%uptick in speed limit violations for aggregated models while about a 40%uptick in the speed limit violations for disaggregated approaches.Conversely,a dis-cernible decline in over-speeding tendencies is observed with camera enforcement,show-casing a 25%reduction over four years.Built environment variables presented mixed results,with one-unit dwellings associated with a 12%increase in over-speeding,while proximity to schools indicated a 10%decrease.These pivotal findings provide policymakers and practitioners with valuable insights to formulate targeted interventions and counter-measures to curtail speed limit violations and bolster overall road safety conditions.展开更多
Speeding likelihood is usually used to measure drivers'propensity of committing speeding.Albeit some studies have analyzed speeding likelihood,most of them are inadequate in considering spatial effects when analyz...Speeding likelihood is usually used to measure drivers'propensity of committing speeding.Albeit some studies have analyzed speeding likelihood,most of them are inadequate in considering spatial effects when analyzing speeding behaviors on urban road networks.This study aims to fill this knowledge gap by modeling speeding likelihood with spatial models and then evaluate the influence of contributing factors.The percent of speeding observations(PSO)is adopted to represent the speeding likelihood.The speeding behaviors and PSO of each floating car(i.e.,taxi)are extracted from the GPS trajectories in Chengdu,China.PSO is modeled by several Bayesian beta general linear models with spatial effects,namely the beta model,beta logit-normal model,beta intrinsic conditional autoregressive(ICAR)model,beta Besag-York-Molli e(BYM)model,and beta BYM2 model.Results show that the beta BYM2 model performs better than other models in terms of data-fitting.According to the estimates from the beta BYM2,spatial correlation is the main reason for the model variability.The roads with more lanes and roads linked by elevated roads are found to increase the speeding likelihood,while higher speed limits,intersection density,traffic congestion,and roadside parking are associated with lower speeding likelihood.These findings provide valuable insights for designing effective anti-speeding countermeasures on urban road networks.展开更多
The present research aimed to identify critical factors that affect speeding behavior.For that purpose,high-resolution smartphone data collected from a naturalistic driving experiment of 88 drivers were utilized,augme...The present research aimed to identify critical factors that affect speeding behavior.For that purpose,high-resolution smartphone data collected from a naturalistic driving experiment of 88 drivers were utilized,augmented with data from self-reported questionnaires.Using risk exposure and driving behavior indicators calculated from smartphone sensor data,as well as demographic characteristics and self-reported driving performance,statistical analysis was carried out for modelling the percentage of driving time over the speed limit,namely by means of generalized linear mixed-effects models.More precisely,an overall model was developed for all road environments,and additional separate models were developed for driving on urban and rural roads.The results from the interpretation of the estimated parameters of the models can be summarized as follows:the parameters of trip distance and mobile phone use while driving have been determined as statistically significant and positively correlated with the percentage of speeding time during a driver's trip.In the same context,male drivers and drivers in the age group of18-34 also increase the percentages of speeding instances while driving.Regarding driving behavior as stated on the questionnaire,it seems that low frequencies of self-declared speeding(never or rarely)are statistically significant and negatively correlated with the percentage of speeding time.It is expected that this research can provide considerable gains to society,since the stakeholders including policy makers and industry could rely on the results and recommendations regarding risk factors that appear to be critical for safe driving.展开更多
Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybr...Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.展开更多
In this study,tropical cyclone(TC)translation speed was introduced as a new similarity factor within the generalized initial value(GIV)framework,enhancing the disaster preassessment capability of the dynamical statist...In this study,tropical cyclone(TC)translation speed was introduced as a new similarity factor within the generalized initial value(GIV)framework,enhancing the disaster preassessment capability of the dynamical statistical analog ensemble forecast model for landfalling TC disasters(DSAEF_LTD model).Three TC translation speed indicators most relevant to TC precipitation were incorporated:the maximum speed on Day 1(the first day of TC-induced precipitation and wind occurring on land)and the average and minimum speeds over All Days(all days of TC-induced precipitation and wind occurring on land),all classified using the Kmeans clustering algorithm.Simulation experiments showed that integrating TC translation speed enhanced the model's performance.The model provided a better optimal common scheme,with the TSS UM(sum of threat scores for severe and above and extremely severe and above disasters)increasing by 2.66%(from 0.5117 to 0.5253)compared with the original model.More importantly,its preassessment ability improved significantly,with the average TSS UM for independent samples increasing by 6.43%(from 0.6488 to0.6905).The modified model demonstrated greater accuracy in capturing disaster severity and distribution of TCs with significant speed characteristics or with regular tracks.This improvement stemmed from reduced false alarms due to the selection of analogs that are more similar to the target TC.The enhanced preassessment ability can be attributed to the key role of TC translation speed,which significantly influences TC precipitation patterns and improves TC precipitation forecasting.Since precipitation is one of the most crucial disaster-causing factors,better TC precipitation forecasting leads to improved disaster preassessment outcomes.These findings emphasize the promising potential of the DSAEF_LTD model for future TC disaster research and management,contributing to the achievement of the Sustainable Development Goals set by the United Nations 2030 Agenda by strengthening coastal resilience.展开更多
During the hoisting process of the offshore substation,changes in the hoisting speed can affect the hoisting system.Therefore,this study set four different speed conditions for the lifting and lowering stages of the i...During the hoisting process of the offshore substation,changes in the hoisting speed can affect the hoisting system.Therefore,this study set four different speed conditions for the lifting and lowering stages of the installation process,and studied the impact of different lifting and lowering speeds on the hoisting system under the same environmental conditions through numerical simulation.The results show that during the lifting operation,as the lifting speed increases,the swing motion of the substation and the installation vessel tends to decrease,and the faster the hoisting speed,the more obvious the swing suppression of the substation and the installation vessel,and the smaller the fluctuation in the tension amplitude of the slings and mooring lines.In contrast,during the lowering operation,as the lowering speed increases,the swing motion of the substation and the installation vessel tends to increase,and the faster the lowering speed,the more obvious the swing amplification effect of the substation and the installation vessel.Therefore,during hoisting operations,increasing the lifting speed and reducing the lowering speed can mitigate the motion performance of the hoisting coupling system,reduce the tension amplitude variation of the sling and mooring,and ensure the smooth progress of the hoisting operation.展开更多
This study aims to explore the impact of combined health education and dietary guidance on the speed of postoperative recovery in patients with gastrointestinal polyps.A specific number of patients who underwent gastr...This study aims to explore the impact of combined health education and dietary guidance on the speed of postoperative recovery in patients with gastrointestinal polyps.A specific number of patients who underwent gastrointestinal polyp resection were selected and randomly divided into a control group and an experimental group.The control group received routine nursing,while the experimental group implemented combined health education and dietary guidance on this basis.By comparing the recovery indicators of the two groups,it was found that the recovery speed of the experimental group was significantly faster than that of the control group,indicating that this combined intervention method can effectively promote patient recovery.展开更多
Wind speed is a crucial parameter affecting wind energy utilization.However,its volatility leads to time-varying power output.Herein,a novel Seq2Seq model integrating deep learning,data denoising,and a shape-aware los...Wind speed is a crucial parameter affecting wind energy utilization.However,its volatility leads to time-varying power output.Herein,a novel Seq2Seq model integrating deep learning,data denoising,and a shape-aware loss function is proposed for accurate multistep wind speed forecasting.In this model,the wind speed data is first denoised using the maximal overlap discrete wavelet transform.Next,an encoder-decoder network based on a temporal convolutional network,bidirectional gated recurrent unit,and multihead self-attention is employed for forecasting.Additionally,to enhance the ability of the model to identify temporal dynamics,a shape-aware loss function,ITILDE-Q,is employed in the model.To verify the effectiveness of the proposed model,a comparative experiment and an ablation experiment were conducted using three datasets of measured wind speeds.Three error metrics and a similarity metric were adopted for comprehensive evaluation.The experimental results showed that the proposed model consistently outperforms benchmark models in all tested forecasting scenarios,with particularly pronounced differences in performance over longer forecast horizons.Furthermore,the synergistic interaction of the three key components contributes to the extraordinary performance of the proposed model.展开更多
基金The National Natural Science Foundation of China(No. 52072012)。
文摘To reduce the risk of traffic accidents significantly caused by the speeding behavior of electric bicycles,this study focuses on the Beijing Yizhuang Economic and Tech-nological Development Zone.This work relies on high-precision shared electric bicycle Global Positioning System trajectory data,integrating a spatiotemporal analysis model and geographic information system(GIS)technol-ogy to explore the spatial and temporal variability law and formation mechanism of speeding behavior.Through data preprocessing,speeding events are identified,and weekday features are extracted.Four periods are identified:morning peak,midday minipeak,evening peak,and nighttime flat peak.Using the GIS platform,global spatial autocorrela-tion and local clustering analysis are conducted to identify the spatial clustering characteristics of speeding behaviors and hotspot areas.The coldspot and hotspot patterns of speeding events and the dynamic trajectories of their evolu-tion are analyzed using spatiotemporal cube technology.The results show that speeding behaviors are strongly corre-lated with the commuting peak in time and spatially concen-trated in the intersections of urban main roads,the periphery of commercial complexes,and industrial parks,with a dif-fusion tendency.The results of this study provide novel in-sights into the research and analysis of the spatial and tempo-ral characteristics of speeding risk behaviors of electric bi-cycles and effective technical support for nonmotorized traf-fic safety management.
文摘Multi-frictional disks are employed to transmit the torque in speeding wetclutch, and the oil thickness within frictional disks could be adjusted for practical outputspeeding. As oil combined with alpha-hydrocarbon or polyester is getting widely used as lubricantand the speeding wet clutch works within hydrodynamic lubrication, mixture lubrication, boundarylubrication and contact situation, established the thermal analysis model for investigating thebehavior of frictional disks in speeding wet clutch, which covers the power-law fluid model,Patir-Cheng average flow model, GT asperity contact model, oil film inertia and heat effects, meanenergy equation, and heat conduction equation. The formulas in the model are deduced. The numeralcalculation and analysis for hydrodynamic lubrication and mixture lubrication are executed.Relationships and variations among transmitting torque, mean push pressure, output speed, and loadare presented. Thermal effect should be considered during the hydrodynamic lubrication and largertransmitting torque makes earlier entrance to mixture lubrication.
文摘China is the main silk producer in the world, whose RSS (Raw Silk Standard)is widely approved in international trade. After entering WTO, China needs to revise the RSSaccording to the changes of silk industry and develop advanced electronic testing system and improvetesting means, so as to promote the internationlization of the RSS. 1. The international standingof Chinese silk The silk consisting of 18 amino acids has the similar protein structure to people'sskin. It is enjoyed by most people for it' s comfortable, magnificent and noble features and ispraised to be the second skin for its unique effects on health and adjusting the body water. In the21st century, silk is the main international fashion as the representative of green products.
文摘In recent years, the subcontracting production for foreign trade of the Xi’an Aviation Engine Company (XAEC), a foreign trade production base of China, has achieved rapid development. In 1994, the company’s export earnings from foreign trade made a breakthrough at US$11 million, and it was commended by the State Economic
文摘To introduce foreign capital for the municipal highway construction is a great measure to meet the development of the socialist market economy and to reform the investment system for the municipal highway construction. The aim of the reform lies in taking the construction and management of the municipal highway facilities as an industry to operate, widening the investment channel of the municipal highway construction and gradually forming a benign cycle of investment-construc-
文摘According to customs statistics, China’s exports of machinery and electric products in 1996 were worth US$ 48.21 billion, an increase of 9.9 percent over the preceding year, and 8.4 percent higher than the growth rate of the nation’s total exports. The proportion of machinery and electric product exports in the nation’s total foreign trade volume\ increased from 29.5 percent in 1995 to 31.9 percent in 1996, a growth at 2.4 percent.
文摘Housing isone of the necessities of humansfor existence and development.The Chinese government hasalways attached great importanceto housing construction;especially in recent years,thepriority development of housingconstruction has been seen inthe real estate and propertiesindustry.Hou Jie,Minister ofConstruction,not long ago wrotean article summarizing theachievements made in this sectorand drawing a blueprint forspeedup of housing constructionand the improvement of livingconditions in the future.It willprovide a vast vista for thedevelopment of China’s buildingindustry and its internationalcooperation.
文摘High-speed railways have the merits of high speed, high transport capacity, low consumption of energy, less pollution, less occupation of land, and greater safety. The development of high-speed railways is suitable for the national conditions in China.The authors suggest that, with the Hu-Ning (Shanghai-Nanjing) section of the Jing-Hu (Beijing-Shanghai) Railway as the starting point, a high-speed dedicated passenger railway line be built to realize the separate transportation of passengers and goods, thus easing the strain on transport in East China, accumulating experience for the future development of high-speed railways, and bringing along the development of high and new technology industries.
文摘This paper discusses the urgency to further develop China’s space technological industry;analyzes the gaps between China and other advanced countries in space industry,including technological level,development scale,application scope and investment;describes the current severe situation that the China’s space industry is faced with and proposes the overall objective,guiding principles and major tasks of China’s space technological sector in the Ninth-Five Year Plan and the coming decade.Finally,it proposes some policies and effective measures to speed up the development of China’s space industry to meet the challenge in the 21st century.
基金the Maryland State Highway Association (SHA) for its funding support throughout the study
文摘Speeding in a work zone needs to be tackled effectively to enhance work zone safety. This study evaluates the influence of three different work zone signs—speed photo enforced signs, dynamic speed display signs and reduced speed limit signs—on driver speeding behavior using a medium-fidelity driving simulator. The speed photo enforced and reduced speed limit signs were placed at intervals before the start of the work zone and in the work zone. A virtual work zone network was built to replicate the Baltimore–Washington Parkway(MD-295). A total of 66 participants from different socioeconomic backgrounds participated in 264 driving simulation sessions. The speeds were measured over four phases: initial speed area, sign visible area, sign readable area and post sign area. An analysis of variance and post hoc analysis showed that the speed photo enforced sign was the most effective of the three signs. The second speed photo enforced sign within the work zone was more effective at reducing speed than the sign before the start of the work zone, especially in the post sign area. It was observed that female participants tend to slow down more when encountering a speed photo enforcement sign.
文摘Over-speeding is a pivotal factor in fatal traffic crashes globally,necessitating robust speed management strategies to augment road safety.In 2021,the National Highway Traffic Safety Administration reported over 12000 speed-related fatalities in the United States alone.Previous studies aggregated over-speeding tendencies;however,the extent of over-speeding has a significant implication on the crash outcome.This study delves into the prevalence and magnitude of over-speeding in various scenarios,utilizing data from traffic cameras in Edmonton,Canada,and employing a negative binomial statistical model for analysis.The model elucidates the significance and likelihood of over-speeding tenden-cies by incorporating temporal and built environment variables,i.e.,year,month,number of lanes,dwelling unit types,school-related,and open green space.Study results indicated that the aggregation of the over-speeding data tends to underestimate the influence of var-ious factors.Notably,the estimated impact of the posted speed limit for the disaggregated models is up to over two times that for the aggregated model.Further,the summer months exhibit a roughly 25%uptick in speed limit violations for aggregated models while about a 40%uptick in the speed limit violations for disaggregated approaches.Conversely,a dis-cernible decline in over-speeding tendencies is observed with camera enforcement,show-casing a 25%reduction over four years.Built environment variables presented mixed results,with one-unit dwellings associated with a 12%increase in over-speeding,while proximity to schools indicated a 10%decrease.These pivotal findings provide policymakers and practitioners with valuable insights to formulate targeted interventions and counter-measures to curtail speed limit violations and bolster overall road safety conditions.
基金supported by the Open Fund of Key Laboratory of Flight Techniques and Flight Safety(FZ2021KF05)the National Natural Science Foundation of China(71801182)+3 种基金the Fundamental Research Funds for the Central Universities(AUGA5710010222)the Opening Project of Intelligent Policing Key Laboratory of Sichuan Province(ZNJW2023KFZD001)the Natural Science Foundation of Heilongjiang Province of China(LH2022E074)the Smart Transportation Safety International Joint Lab Program。
文摘Speeding likelihood is usually used to measure drivers'propensity of committing speeding.Albeit some studies have analyzed speeding likelihood,most of them are inadequate in considering spatial effects when analyzing speeding behaviors on urban road networks.This study aims to fill this knowledge gap by modeling speeding likelihood with spatial models and then evaluate the influence of contributing factors.The percent of speeding observations(PSO)is adopted to represent the speeding likelihood.The speeding behaviors and PSO of each floating car(i.e.,taxi)are extracted from the GPS trajectories in Chengdu,China.PSO is modeled by several Bayesian beta general linear models with spatial effects,namely the beta model,beta logit-normal model,beta intrinsic conditional autoregressive(ICAR)model,beta Besag-York-Molli e(BYM)model,and beta BYM2 model.Results show that the beta BYM2 model performs better than other models in terms of data-fitting.According to the estimates from the beta BYM2,spatial correlation is the main reason for the model variability.The roads with more lanes and roads linked by elevated roads are found to increase the speeding likelihood,while higher speed limits,intersection density,traffic congestion,and roadside parking are associated with lower speeding likelihood.These findings provide valuable insights for designing effective anti-speeding countermeasures on urban road networks.
基金co-financed by the European Union-European Regional Development Fund (ERDF)and Greek national funds through the Operational Program“Competitiveness,Entrepreneurship and Innovation” (EPAnEK)of the National Strategic Reference Framework (NSRF)-Research Funding Program:BeSmart-multi-modal driver behavior and safety support system on the basis of smartphone applications。
文摘The present research aimed to identify critical factors that affect speeding behavior.For that purpose,high-resolution smartphone data collected from a naturalistic driving experiment of 88 drivers were utilized,augmented with data from self-reported questionnaires.Using risk exposure and driving behavior indicators calculated from smartphone sensor data,as well as demographic characteristics and self-reported driving performance,statistical analysis was carried out for modelling the percentage of driving time over the speed limit,namely by means of generalized linear mixed-effects models.More precisely,an overall model was developed for all road environments,and additional separate models were developed for driving on urban and rural roads.The results from the interpretation of the estimated parameters of the models can be summarized as follows:the parameters of trip distance and mobile phone use while driving have been determined as statistically significant and positively correlated with the percentage of speeding time during a driver's trip.In the same context,male drivers and drivers in the age group of18-34 also increase the percentages of speeding instances while driving.Regarding driving behavior as stated on the questionnaire,it seems that low frequencies of self-declared speeding(never or rarely)are statistically significant and negatively correlated with the percentage of speeding time.It is expected that this research can provide considerable gains to society,since the stakeholders including policy makers and industry could rely on the results and recommendations regarding risk factors that appear to be critical for safe driving.
文摘Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.
基金supported by the Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province(No.SCSF202307)the Basic Research Fund of CAMS(No.2023Z016)+1 种基金the National Natural Scientific Foundation of China(No.42275037)the Jiangsu Collaborative Innovation Center for Climate Change。
文摘In this study,tropical cyclone(TC)translation speed was introduced as a new similarity factor within the generalized initial value(GIV)framework,enhancing the disaster preassessment capability of the dynamical statistical analog ensemble forecast model for landfalling TC disasters(DSAEF_LTD model).Three TC translation speed indicators most relevant to TC precipitation were incorporated:the maximum speed on Day 1(the first day of TC-induced precipitation and wind occurring on land)and the average and minimum speeds over All Days(all days of TC-induced precipitation and wind occurring on land),all classified using the Kmeans clustering algorithm.Simulation experiments showed that integrating TC translation speed enhanced the model's performance.The model provided a better optimal common scheme,with the TSS UM(sum of threat scores for severe and above and extremely severe and above disasters)increasing by 2.66%(from 0.5117 to 0.5253)compared with the original model.More importantly,its preassessment ability improved significantly,with the average TSS UM for independent samples increasing by 6.43%(from 0.6488 to0.6905).The modified model demonstrated greater accuracy in capturing disaster severity and distribution of TCs with significant speed characteristics or with regular tracks.This improvement stemmed from reduced false alarms due to the selection of analogs that are more similar to the target TC.The enhanced preassessment ability can be attributed to the key role of TC translation speed,which significantly influences TC precipitation patterns and improves TC precipitation forecasting.Since precipitation is one of the most crucial disaster-causing factors,better TC precipitation forecasting leads to improved disaster preassessment outcomes.These findings emphasize the promising potential of the DSAEF_LTD model for future TC disaster research and management,contributing to the achievement of the Sustainable Development Goals set by the United Nations 2030 Agenda by strengthening coastal resilience.
基金support from the National Natural Science Foundation of China(No.52271287)funding from the State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation,Tianjin University。
文摘During the hoisting process of the offshore substation,changes in the hoisting speed can affect the hoisting system.Therefore,this study set four different speed conditions for the lifting and lowering stages of the installation process,and studied the impact of different lifting and lowering speeds on the hoisting system under the same environmental conditions through numerical simulation.The results show that during the lifting operation,as the lifting speed increases,the swing motion of the substation and the installation vessel tends to decrease,and the faster the hoisting speed,the more obvious the swing suppression of the substation and the installation vessel,and the smaller the fluctuation in the tension amplitude of the slings and mooring lines.In contrast,during the lowering operation,as the lowering speed increases,the swing motion of the substation and the installation vessel tends to increase,and the faster the lowering speed,the more obvious the swing amplification effect of the substation and the installation vessel.Therefore,during hoisting operations,increasing the lifting speed and reducing the lowering speed can mitigate the motion performance of the hoisting coupling system,reduce the tension amplitude variation of the sling and mooring,and ensure the smooth progress of the hoisting operation.
文摘This study aims to explore the impact of combined health education and dietary guidance on the speed of postoperative recovery in patients with gastrointestinal polyps.A specific number of patients who underwent gastrointestinal polyp resection were selected and randomly divided into a control group and an experimental group.The control group received routine nursing,while the experimental group implemented combined health education and dietary guidance on this basis.By comparing the recovery indicators of the two groups,it was found that the recovery speed of the experimental group was significantly faster than that of the control group,indicating that this combined intervention method can effectively promote patient recovery.
基金supported by the National Natural Science Foundation of China(No.52171284)。
文摘Wind speed is a crucial parameter affecting wind energy utilization.However,its volatility leads to time-varying power output.Herein,a novel Seq2Seq model integrating deep learning,data denoising,and a shape-aware loss function is proposed for accurate multistep wind speed forecasting.In this model,the wind speed data is first denoised using the maximal overlap discrete wavelet transform.Next,an encoder-decoder network based on a temporal convolutional network,bidirectional gated recurrent unit,and multihead self-attention is employed for forecasting.Additionally,to enhance the ability of the model to identify temporal dynamics,a shape-aware loss function,ITILDE-Q,is employed in the model.To verify the effectiveness of the proposed model,a comparative experiment and an ablation experiment were conducted using three datasets of measured wind speeds.Three error metrics and a similarity metric were adopted for comprehensive evaluation.The experimental results showed that the proposed model consistently outperforms benchmark models in all tested forecasting scenarios,with particularly pronounced differences in performance over longer forecast horizons.Furthermore,the synergistic interaction of the three key components contributes to the extraordinary performance of the proposed model.
