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In this paper, a dynamic entry pedestrian flow assignment problem is investigated. The problem concerns a scenario, i.e. a number of pedestrians enter a public place with multiple entrances and internal obstacles, and then get to their destinations in the public place. The problem aims at determining the access entrance, moving route, and destination position choice of pedestrians so as to minimize the total entry time of all pedestrians. A mesoscopic model is developed to formulate the dynamic entry process of pedestrians in the scenario and a heuristic algorithm is proposed to solve the dynamic entry pedestrian flow assignment problem. Moreover, a set of numerical investigations are provided to demonstrate the applications of the model and the effectiveness of the algorithm, especially to a case with a larger number of entry pedestrians. [ABSTRACT FROM AUTHOR]

Suitable information of routes and exits can help guide evacuees to approach the expected destinations more efficiently in case of emergencies, such as fire accidents, terrorist attacks and power failures. Therefore, the purpose of this paper is to provide an overview of the dynamics of two patterns of guided crowd evacuation. One is source-guided crowd evacuation, and the other is leader-guided crowd evacuation. In source-guided crowd evacuation, sources located in fixed positions diffuse information to evacuees around them in a certain form such as light, sound and smell. However, in the leader-guided crowd evacuation, leaders convey information to evacuees they encounter along their trajectories by means of word-of-mouth communication. First, considering wall-following, herding, and inertia behaviors, a mesoscopic model is established to formulate the movement of uninformed pedestrians without information guidance. Then, considering information guidance, a set of movement rules are constructed to describe the evolution dynamics of crowds comprising uninformed and informed pedestrians. Further, the implementation of the simulation models reveals the subtle effects of the initial position of information sources, the propagation velocity of information sources, and the initial distribution of leaders on the evacuation efficiency of crowds. This study gives new insights into the design of information guidance systems in pedestrian walking facilities. [ABSTRACT FROM AUTHOR]

We consider a bottleneck system in a state of disequilibrium, in which commuters are heterogeneous in the values of travel time and schedule delays. Three representative dynamical systems are used to formulate the day-to-day departure time choice of commuters, and a Walrasian toll charge scheme is utilized to control the evolutionary process of traffic flows. The toll charge scheme is anonymous; that is, toll charges are identical for all user classes, and the scheme's implementation does not need to resort to information on the values of travel time and schedule delays. We find that the system optimum (SO) flow pattern can be achieved at the stationary state under the implementation of the toll charge scheme. The equivalence between the stationary state and the SO, the existence of the toll charge for achieving the SO, and the convergence of day-to-day traffic flows to the SO under the implementation of the toll charge scheme are theoretically proved. The distributions of traffic flows and toll charges at the SO state during morning rush hour are analytically shown. The application of the toll charge scheme to a network with multiple trip origins is presented. The effectiveness of the toll charge scheme for achieving the SO is also examined by numerical analyses. Funding: This work was supported by the National Natural Science Foundation of China [Grants 72171007, 71890972/71890970, and 72021001]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2022.1191. [ABSTRACT FROM AUTHOR]

In this study, we conducted a series of experiments to investigate child behavior during self-evacuation and guided evacuation under non-emergency and emergency situations. The properties of child flow dynamics are obtained through analysis of the experimental video recordings. It is found that under a non-emergency situation, the evacuation processes are orderly, and group and waiting behavior can be observed. Under an emergency situation, the evacuation processes become disorder, and running and pushing behaviors can be observed. Our analyses showed that the exit use is imbalanced under an emergency situation and that the guidance of teachers plays a positive role in the exit choice of children during an emergency evacuation process. The emergency degree has significant effects on the exit choice of children in self-evacuation. Our results also showed that the average evacuation time of children, flow rate, and average headway of the exit are less affected by the guidance of teachers and more affected by the emergency degree. The guidance of teachers affects some children's individual evacuation time. The findings can assist in improvements in the daily management and evacuation strategies for children, as well as the development and validation of child simulation models. [ABSTRACT FROM AUTHOR]

This paper studies the impact of route choice set of networks on the day-to-day traffic dynamics through conducting a group of experiments, in which four traffic networks with different sets for choice are used. It is observed that a deterministic user equilibrium (DUE) state is difficult to sustain and the probability of reaching DUE is larger in a network with smaller route choice set. Three day-to-day models are calibrated by using the experimental data. Results reveal that (1) there are linear relationships between traffic volume/flow changes obtained from the experiments and models; (2) when the same model is applied to different networks, the calibrated adjustment parameters are statistically different; and (3) the same model reveals different performances for different networks. Besides, it is shown the participants are more likely to change route choices in a network with larger route choice set and tend to switch away after experiencing a longer travel time. [ABSTRACT FROM AUTHOR]

Background: The statistical association between a short-term rise in low-density lipoprotein cholesterol (LDL-C) levels and the short-term outcome of acute ischemic stroke remains unknown. We aimed to evaluate the association in acute ischemic stroke patients during hospitalization. Methods: Patients with acute ischemic stroke who received statin at discharge were enrolled in this multicenter registry study. LDL-C values were measured on the first day after admission and on the day before discharge to determine the rise in LDL-C levels. Poor outcome was defined as a modified Ranking Scale score ≥2 at discharge. The National Institutes of Health Stroke Scale increase from admission to discharge by 2 points was defined as clinical deterioration. Logistic regression analyses were used to analyze the relationship between LDL-C rise during hospitalization and poor outcome at discharge. Variables that were significantly different between the LDL-C rise and LDL-C fall groups were considered in adjustment for confounding variables in model 1. Age, sex, and those variables in model 1 were considered in adjustment for confounding variables in model 2. Results: Among the 676 patients, 110 (16.3%) showed a rise in LDL-C levels during hospitalization. Multivariate analyses showed that LDL-C at admission <1.6 mmol/L was significantly correlated with LDL-C rise during hospitalization (p < 0.001). There were significantly more patients with a poor outcome in the "LDL-C rise" group than in the "LDL-fall" group (p = 0.002). Multiple models consistently showed that LDL-C rise increased the risk of a poor outcome at discharge in model 1 (OR [95% CI] 1.351 [1.059–1.723], p = 0.016) and model 2 (OR [95% CI] 1.370 [1.071–1.751], p = 0.012). LDL-C rise also increased the risk of clinical deterioration, although its p value only was 0.043 in model 1 and 0.048 in model 2. Conclusions: Rise in LDL-C during hospitalization from acute ischemic stroke is an independent predictor of poor outcome at discharge. In particular, patients with lower LDL-C values at admission are a higher at risk, and LDL-C in these patients should thus be monitored while in hospital. [ABSTRACT FROM AUTHOR]

The efficacy of the principal–agent contract in supply-chain quality control depends not only on contract parameters but also such noncontract parameters as cost of a high-quality effort and the diagnostic error of the inspection policy. The noncontract parameters usually fluctuate and are unobservable during contract execution, which may hinder suppliers' high-quality effort, or, in other words, result in a lower efficacy for the contract. This article proposes an ontology-based approach to facilitating a principal–agent contract by monitoring the contract's loss of efficacy. The approach consists of ontology-based models and data-centric algorithms. The ontology-based models not only formally represent concepts and relations between concepts involved in predicting whether a contract is efficient, but also organise multichannel data such as news, marketplace reports and industry databases containing information of factors impacting the unobservable noncontract parameters' fluctuations. Based on the ontology-based models and multichannel data, the data-centric algorithms are developed to predict whether a contract will lose efficacy. We evaluate our approach through case study, simulation and comparison against related approaches to supply-chain quality control. The case study proves that our approach is appropriate. In the simulation evaluation, a combination of our approach and principal–agent contract is more efficient than just a principal–agent contract. The comparison results against related approaches show that our approach is a novel, inexpensive and directly applicable tool for reducing both asymmetric information and moral hazard in supply-chain quality control. [ABSTRACT FROM AUTHOR]

We study a class of pedestrian evacuation process in rooms without visibility by analytical and simulative methods. First, the moving distance of pedestrians for leaving the rooms is analyzed using the mean and variance theory. A microscopic pedestrian model is then extended to simulate pedestrian evacuation in the rooms. By numerical examples, the distributions of single individual’s evacuation efficiency in the rooms and the improvement by increasing the number of exits for the individual’s evacuation efficiency are demonstrated. Pedestrians’ moving distances obtained by analytical and simulative methods are also compared. The study is helpful for assessing the efficiency of evacuation and the safety of buildings under conditions of invisibility. [ABSTRACT FROM PUBLISHER]

We propose a pedestrian position update rule, which is added to a microscopic pedestrian model to avoid pedestrian overlap. In the rule, the step size of a pedestrian moving in a selected direction at each update is in inverse proportion to the repulsive actions imposed by other pedestrians moving in a direction with an exponential rate. The positions of the pedestrians are then updated in each small time interval. In this way, a barrier between the pedestrians can be generated, and after updating their positions the pedestrians do not overlap with each other. The modified model is compared to the original model through a simulation of the evacuation process of pedestrians in a closed area. The simulation results indicate that the modified model is superior to the original model in several aspects. [ABSTRACT FROM AUTHOR]

A modified floor field model is proposed to simulate pedestrian evacuation in rooms with internal obstacles and multiple exits. The modifications lie in developing a method to calculate the static floor field for every lattice site, which is determined by the most feasible distance to an exit, and employing a logit-based discrete choice principle to govern the exit selection. Simulation results show that the evacuation time is sensitive to the exit position and some model parameters. For pedestrians unfamiliar with the exit location, additional doors may not be necessary and can cause a negative effect on evacuation time. It is also found that unfamiliarity with the room's inner configuration and blindly following others will lead to an increase of the evacuation time.