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Day-to-day traffic user equilibrium model considering influence of intelligent highways and advanced traveler information systems 被引量:1
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作者 SUN Chao CHU Zhao-ming +1 位作者 ZHANG Peng CHANG Yu-lin 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第4期1376-1388,共13页
To explore the influence of intelligent highways and advanced traveler information systems(ATIS)on path choice behavior,a day-to-day(DTD)traffic flow evolution model with information from intelligent highways and ATIS... To explore the influence of intelligent highways and advanced traveler information systems(ATIS)on path choice behavior,a day-to-day(DTD)traffic flow evolution model with information from intelligent highways and ATIS is proposed,whereby the network reliability and experiential learning theory are introduced into the decision process for the travelers’route choice.The intelligent highway serves all the travelers who drive on it,whereas ATIS serves vehicles equipped with information systems.Travelers who drive on intelligent highways or vehicles equipped with ATIS determine their trip routes based on real-time traffic information,whereas other travelers use both the road network conditions from the previous day and historical travel experience to choose a route.Both roadway capacity degradation and travel demand fluctuations are considered to demonstrate the uncertainties in the network.The theory of traffic network flow is developed to build a DTD model considering information from intelligent highway and ATIS.The fixed point theorem is adopted to investigate the equivalence,existence and stability of the proposed DTD model.Numerical examples illustrate that using a high confidence level and weight parameter for the traffic flow reduces the stability of the proposed model.The traffic flow reaches a steady state as travelers’routes shift with repetitive learning of road conditions.The proposed model can be used to formulate scientific traffic organization and diversion schemes during road expansion or reconstruction. 展开更多
关键词 day-to-day model intelligent highway advanced traveler information systems UNCERTAINTY
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Trends in day-to-day variability of surface air temperature in China during 1961-2012
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作者 LI Shang-Feng JIANG Da-Bang +1 位作者 LIAN Yi YAO Yao-Xian 《Atmospheric and Oceanic Science Letters》 CSCD 2017年第2期122-129,共8页
Using daily mean, maximum, and minimum surface air temperature (abbreviated as Tmean, Tmax, and Tmin, respectively) data from CN05.2 and the Met Office Hadley Centre observation data-sets for 1961-2012, the trends i... Using daily mean, maximum, and minimum surface air temperature (abbreviated as Tmean, Tmax, and Tmin, respectively) data from CN05.2 and the Met Office Hadley Centre observation data-sets for 1961-2012, the trends in day-to-day variability of Tmean, Tmax, and Tmin (abbreviated as DVTFmean, DVTTmax, and DVTTmin, respectively) are examined. It is revealed that the annual trends of DVTTmean, DVTTmax, and DVTTmin are all negative in Northeast China (NEC), and more obvious in North China than in South China. Seasonal trends of DVTTmean are also negative in NEC, except in summer. For DVTTmax, trends are generally more obvious than DVTTmin in all seasons in NEC; moreover, trends in spring are obvious in both the north and the south, but trends in summer and winter are more obvious in the southern region than in the northern part. As far as DVTT-Fmin is concerned, except in autumn, seasonal trends are more obvious in the north than in other regions of the country. 展开更多
关键词 day-to-day variability TEMPERATURE TREND China
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Compared with insulin glargine, insulin degludec narrows the day-to-day variability in the glucose-lowering effect rather than lowering blood glucose levels
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作者 Susumu Ogawa Kazuhiro Nako +3 位作者 Masashi Okamura Miho Senda Takuya Sakamoto Sadayoshi Ito 《Journal of Diabetes Mellitus》 2013年第4期244-251,共8页
Background: Changes in the day-to-day variability in the glucose-lowering effect of insulin [fluctuations of blood glucose levels (BG) seen during the same time period] that occur when insulin glargine (glargine) is r... Background: Changes in the day-to-day variability in the glucose-lowering effect of insulin [fluctuations of blood glucose levels (BG) seen during the same time period] that occur when insulin glargine (glargine) is replaced with insulin degludec (degludec) have not been sufficiently evaluated. Subjects: Five diabetics with unstable BG undergoing basal-bolus treatment using insulin glargine as basal insulin. Methods: Basal insulin was changed from glargine to same-dose degludec. The subjects’ HbA1c, glycoalbumin, and 1.5-anhydro-D-glucitol were measured before and after the switchover. Fasting blood glucose concentration (FBG) and predinner blood glucose concentration (PDBG) were measured continuously for 28 days immediately before the switchover, and 28 days immediately thereafter, to compare and evaluate 1) the changes in their mean values and standard deviations (SDs) before and after the switchover, and 2) the frequency of appearance of BG of over 180 mg/dL (BG ≥ 180) and under 70 mg/dL (BG Results: The levels of HbA1c, glycoalbumin, FBG’s mean value, SDs, BG ≥ 180 and BG Conclusion: The possibility was shown that degludec, to a greater extent than glargine, suppressed daily fluctuations of FBG and PDBG, suppressed the occurrence frequency of hyperglycemia and hypoglycemia, and exerted more steady hypoglycemic actions. 展开更多
关键词 Degludec GLARGINE Hyperglycemia HYPOGLYCEMIA The day-to-day VARIABILITY in the Glucose-Lowering EFFECT of Insulin
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Investigating day-to-day route choices based on multi-scenario laboratory experiments, Part Ⅱ: Route-dependent attraction-based stochastic process model
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作者 Hang Qi Ning Ji +1 位作者 Xiaobo Qu Zhengbing He 《Communications in Transportation Research》 2024年第1期92-107,共16页
Laboratory experiments are one of the important means used to investigate travel choice behavior under strategic uncertainty.Many experiment-based studies have shown that the Nash equilibrium can predict aggregated ro... Laboratory experiments are one of the important means used to investigate travel choice behavior under strategic uncertainty.Many experiment-based studies have shown that the Nash equilibrium can predict aggregated route choices,while the fluctuations,whose mechanisms are still unclear,continue to exist until the end.To understand the fluctuations,this paper proposes a route-dependent attraction-based stochastic process model,which shares exactly the same behavioral foundation introduced in Part I of the study(Qi et al.,2023),i.e.,route-dependent inertia and route-dependent preference.The model predictions are carefully compared with the experimental observations obtained from the congestible parallel-route laboratory experiments containing 312 subjects and eight decision-making scenarios(Qi et al.,2023).The results show that the proposed stochastic process model can precisely reproduce the random oscillations both in terms of flow switching and route flow evolution.Subsequently,an approximated model is developed to enhance the efficiency in evaluating the equilibrium distribution,providing a practical tool to evaluate the impacts of transportation policies in both long-and short-term runs.To the best of our knowledge,this paper is the first attempt to model and explain experimental phenomena by introducing stochastic process theories,as well as a successful example of applying experimental economics methodology to improve our understanding of human travel choice behavior. 展开更多
关键词 day-to-day dynamics Route choice behavior Markov process Stochastic process
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A topology-based bounded rationality day-to-day traffic assignment model 被引量:4
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作者 Enrico Siri Silvia Siri Simona Sacone 《Communications in Transportation Research》 2022年第1期298-313,共16页
This paper analyzes the day-to-day adjustment process of users’behaviors in a transport network which is affected by relevant alterations such as disruptions due to critical events which cause the impossibility to us... This paper analyzes the day-to-day adjustment process of users’behaviors in a transport network which is affected by relevant alterations such as disruptions due to critical events which cause the impossibility to use one or more links.For representing the progressive adjustment of the flows on the network to reach a new equilibrium,a dayto-day discrete-time model is proposed,based on the idea that people are bounded rational in their choices,i.e.they often do not behave according to the optimal solution but they accept solutions they consider satisfying.Users,in their choice process,are influenced by the topological similarity between the route they are currently using and others.This means that they tend to prefer the solutions that are more similar to the one they are already using.In parallel,users exhibit a myopic behavior,i.e.,they tend to overestimate the goodness of a route if,when using it,they suddenly experience a significant reduction in travel time compared to what they are used to.In the paper it is shown that such route choice behaviour implies that the steady state of the system corresponds to a Bounded Rational User Equilibrium,i.e.,a state that does not diverge from the user equilibrium more than a certain value which increases when the relative importance given to the topological similarity grows.The model also assumes that these biases vanish,at least with respect to those routes that are most frequently used by users,after a sufficient amount of time.Under certain conditions,it is then shown that the steady state can eventually collapse into a User Equilibrium.The effectiveness of the proposed model is assessed via simulation results in which two test networks are analyzed in detail to show the evolution of the users’behaviour in a transport network after a disruption. 展开更多
关键词 Traffic Assignment day-to-day traffic assignment Bounded rationality
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Assessing the Performance of a Dynamical Downscaling Simulation Driven by a Bias-Corrected CMIP6 Dataset for Asian Climate 被引量:1
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作者 Zhongfeng XU Ying HAN +4 位作者 Meng-Zhuo ZHANG Chi-Yung TAM Zong-Liang YANG Ahmed M.EL KENAWY Congbin FU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第5期974-988,共15页
In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three... In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three simulations were conducted with a 25-km grid spacing for the period 1980–2014.The first simulation(WRF_ERA5)was driven by the European Centre for Medium-Range Weather Forecasts Reanalysis 5(ERA5)dataset and served as the validation dataset.The original GCM dataset(MPI-ESM1-2-HR model)was used to drive the second simulation(WRF_GCM),while the third simulation(WRF_GCMbc)was driven by the bias-corrected GCM dataset.The bias-corrected GCM data has an ERA5-based mean and interannual variance and long-term trends derived from the ensemble mean of 18 CMIP6 models.Results demonstrate that the WRF_GCMbc significantly reduced the root-mean-square errors(RMSEs)of the climatological mean of downscaled variables,including temperature,precipitation,snow,wind,relative humidity,and planetary boundary layer height by 50%–90%compared to the WRF_GCM.Similarly,the RMSEs of interannual-tointerdecadal variances of downscaled variables were reduced by 30%–60%.Furthermore,the WRF_GCMbc better captured the annual cycle of the monsoon circulation and intraseasonal and day-to-day variabilities.The leading empirical orthogonal function(EOF)shows a monopole precipitation mode in the WRF_GCM.In contrast,the WRF_GCMbc successfully reproduced the observed tri-pole mode of summer precipitation over eastern China.This improvement could be attributed to a better-simulated location of the western North Pacific subtropical high in the WRF_GCMbc after GCM bias correction. 展开更多
关键词 bias correction multi-model ensemble mean dynamical downscaling interannual variability day-to-day variability validation
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A self-regulating pairwise swapping algorithm to search reliability-based user equilibrium 被引量:3
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作者 ZHANG Wen-yi GUAN Wei FAN Ling-ling 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第8期2002-2013,共12页
The violation of monotonicity on reliability measures(RMs)usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium(RUE)problem.The swapping algorithms prov... The violation of monotonicity on reliability measures(RMs)usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium(RUE)problem.The swapping algorithms provide a simple and convenient alternative to search traffic equilibrium since they are derivative-free and require weaker monotonicity.However,the existing swapping algorithms are usually based on linear swapping processes which cannot naturally avoid overswapping,and the step-size parameter update methods do not take the swapping feature into account.In this paper,we suggest a self-regulating pairwise swapping algorithm(SRPSA)to search RUE.SRPSA comprises an RM-based pairwise swapping process(RMPSP),a parameter self-diminishing operator and a termination criterion.SRPSA does not need to check the feasibility of either solutions or step-size parameter.It is suggested from the numerical analyses that SRPSA is effective and can swap to the quasi-RUE very fast.Therefore,SRPSA offers a good approach to generate initial points for those superior local search algorithms. 展开更多
关键词 travel time reliability reliability-based user equilibrium day-to-day dynamics route swapping
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A Trend towards a Stable Warm and Windless State of the Surface Weather Conditions in Northern and Northeastern China during 1961–2014 被引量:2
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作者 Bo SUN Huijun WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第6期713-726,共14页
This study investigates the trends in the mean state and the day-to-day variability (DDV) of the surface weather conditions over northern and northeastern China (NNEC) during 1961-2014 using CN05.1 observational d... This study investigates the trends in the mean state and the day-to-day variability (DDV) of the surface weather conditions over northern and northeastern China (NNEC) during 1961-2014 using CN05.1 observational data. In this study, we show that the surface temperature (wind speed) has increased (decreased) over NNEC and that the DDV of the surface temperatures and wind speeds has decreased, indicating a trend towards a stable warm and windless state of the surface weather conditions over NNEC. This finding implies a trend towards more persistent hot and windless episodes, which threaten human health and aggravate environmental problems. The trends are also examined in reanalysis data. Both the ERA-40 and the NCEP data show an increasing (decreasing) trend in the mean state of the surface temperatures (wind speeds). However, the reanalysis data show a consistent decreasing trend in the DDV of the surface weather conditions only in the spring. The underlying reason for the decreased DDV of the surface weather conditions is further analyzed, focusing on the spring season. Essentially, the decreased DDV of the surface weather conditions can be attributed to a decrease in synoptic-scale wave activity, which is caused by a decrease in the baroclinic instability. There is a contrasting change in the baroclinic instability over East Asia, showing a decreasing (increasing) trend north (south) of 40°N. This contrasting change in the baroclinic instability is primarily caused by a tropospheric cooling zone over East Asia at approximately 40°N, which influences the meridional temperature gradient over East Asia. 展开更多
关键词 day-to-day variability surface weather condition TREND northern and northeastern China
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The Stability of Multi-modal Traffic Network
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作者 HAN Ling-Hui Sun Hui-Jun +2 位作者 ZHU Cheng-Juan WU Jian-Jun JIA Bin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第7期48-54,共7页
There is an explicit and implicit assumption in multimodal traffic equilibrium models, that is, if the equilibrium exists, then it will also occur. The assumption is very idealized; in fact, it may be shown that the q... There is an explicit and implicit assumption in multimodal traffic equilibrium models, that is, if the equilibrium exists, then it will also occur. The assumption is very idealized; in fact, it may be shown that the quite contrary could happen, because in multimodal traffic network, especially in mixed traffic conditions the interaction among traffic modes is asymmetric and the asymmetric interaction may result in the instability of traffic system. In this paper, to study the stability of multimodal traffic system, we respectively present the travel cost function in mixed traffic conditions and in traffic network with dedicated bus lanes. Based on a day-to-day dynamical model, we study the evolution of daily route choice of travelers in multimodal traffic network using 10000 random initial values for different cases. From the results of simulation, it can be concluded that the asymmetric interaction between the cars and buses in mixed traffic conditions can lead the traffic system to instability when traffic demand is larger. We also study the effect of travelers' perception error on the stability of multimodal traffic network. Although the larger perception error can alleviate the effect of interaction between cars and buses and improve the stability of traffic system in mixed traffic conditions, the traffic system also become instable when the traffic demand is larger than a number. For all cases simulated in this study, with the same parameters, traffic system with dedicated bus lane has better stability for traffic demand than that in mixed traffic conditions. We also find that the network with dedicated bus lane has higher portion of travelers by bus than it of mixed traffic network. So it can be concluded that building dedicated bus lane can improve the stability of traffic system and attract more travelers to choose bus reducing the traffic congestion. 展开更多
关键词 multi-modal traffic network day-to-day dynamical model STABILITY
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