scholarly journals Pedestrian Evacuation Time Model for Urban Metro Hubs Based on Multiple Video Sequences Data

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Ji-biao Zhou ◽  
Hong Chen ◽  
Jing Yang ◽  
Jiao Yan
Keyword(s):  
Density Variation ◽  
Video Sequences ◽  
Pedestrian Flow ◽  
Time Model ◽  
Evacuation Time ◽  
Safety Coefficient ◽  
Pedestrian Evacuation ◽  
Proposed Model ◽  
Off Time ◽  
Reasonable Model

Evacuation time is a significant safety coefficient for Urban Metro Hubs (UMHs). Usually, a reasonable model for evacuation time will effectively promote the safety for pedestrian when emergency incidents occur in UMHs. In this paper, we propose a pedestrian evacuation time model for UMHs to improve the accuracy and reliability of its evacuation time. Firstly, we design an experiment survey based on the multiple video sequences to analyze the characteristics of pedestrian flow. Then, we decompose the evacuation process on the basis of the parameters, which involve the evacuation characteristics, the speed-density variation law, the pedestrian drop-off time, the platform evacuation time, and the channel evacuation time. Finally, we take the Bei Da-jie metro hub in Xi’an as an example, and verify the feasibility of the proposed pedestrian evacuation time model. The results show that the relative error for the evacuation time between the experiment result and the actual data is only 1.90%, where the experiment time is 169.87 s and the actual time is 166.64 s. Moreover, the proposed model strictly follows the Code for Design of Metro (GB 50157-003) and hence it can provide a good theoretical guidance for innovating the evacuation efficiency and the design reasonability of UMHs.

Pedestrian evacuation behavior analysis and simulation in multi-exits case

2017 ◽  
Vol 28 (10) ◽  
pp. 1750128 ◽  
Author(s):  
Yongxing Li ◽  
Hongfei Jia ◽  
Jun Li ◽  
Jian Gong ◽  
Kechao Sun
Keyword(s):  
Cellular Automata ◽  
Choice Model ◽  
Current Position ◽  
Time Model ◽  
Evacuation Time ◽  
Pedestrian Evacuation ◽  
Shortest Distance ◽  
Evacuation Behavior ◽  
Exit Choice ◽  
Pedestrian Simulation

Considering the process of pedestrian evacuation as pedestrian walking freely from current position to exit and queuing at the exit, estimated evacuation time model for single pedestrian is established. Based on estimated evacuation time and shortest distance, pedestrian exit choice model is established considering pedestrian preference. Pedestrian exit choice model is added into pedestrian simulation model which is built based on cellular automata. Pedestrian evacuation behavior in multi-exits case is simulated. The simulations indicate that pedestrian evacuation model built in our work describes the pedestrian evacuation behavior well.

Reliability Analysis of Relevant Radom Variables in Pedestrian Evacuation Study in Underground Transportation Hub

2014 ◽  
Vol 1020 ◽  
pp. 741-746
Author(s):  
Dong Fu Zhao ◽  
Xiao Lin Zhang ◽  
Yu Su
Keyword(s):  
Limit State ◽  
State Equation ◽  
Flow Coefficient ◽  
Research Model ◽  
Pedestrian Flow ◽  
Evacuation Time ◽  
Absolute Value ◽  
Pedestrian Evacuation ◽  
Underground Transportation ◽  
Export Flow

In this study reliability theory was applied in evacuation time of pedestrians in the subway, especially taking the correlation of pedestrian speed and pedestrian flow coefficient into account. Firstly, the traditional evacuation time design formula was regarded as research model. Statistical distribution of pedestrian speed and pedestrian flow coefficient in the model was analyzed .Thus the reliability limit state equation was built. Then the evacuation time’s reliability probability was obtained according to the checking point method of generalized random space. At last the process of how different factors influence the reliability was analyzed. Results show that we should consider the correlation between pedestrian speed and export flow rate when correlation is big (absolute value is greater than 0.5, for example).Our conclusions will contribute to related research and the formulation of actual planning.

scholarly journals A Stairs Evacuation Model Considering the Pedestrian Merging Flows

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xia Zhong Zheng ◽  
Dan Tian ◽  
Ming Zhang ◽  
Chaoran Hu ◽  
Liyang Tong
Keyword(s):  
Pedestrian Flow ◽  
Output Rate ◽  
Evacuation Time ◽  
Building Evacuation ◽  
Complex Interactions ◽  
Proposed Model ◽  
Three Stages ◽  
Evacuation Model ◽  
The Impact

Pedestrian merging flows are common in a stairs evacuation process, which involves complex interactions among pedestrians that substantially restrict the efficiency of the stairs evacuation process. Analyzing the pedestrian merging flows process and improving the efficiency of stairs evacuation are urgent and essential tasks. A novel simplified stairs evacuation model for simulating and analyzing the stairs evacuation process, which considers the impact of merging flows, is proposed in this process. The dynamic pedestrian output rate of a floor platform is calculated by the number of pedestrians on the floor platform. The merging ratio determined by the design size of stairs is adopted to determine the ratio between the stairs pedestrian flow and the floor pedestrian flow in the pedestrian output rate of the floor platform. To evaluate the stairs evacuation process is divided into three stages based on the pedestrian merging flows process, and the evacuation time at each stage is computed by the dynamic pedestrian output rate of the floor platform. The stairs evacuation capacity is calculated by the evacuation time and the number of pedestrians. A case study of a six-floor building evacuation is investigated, and the reliability and feasibility of the proposed model is verified. By establishing different merging ratios, the optimal merging ratio is obtained by comparing the evacuation capacities of different merging ratios, which provides a reference of stairs design for designers.

scholarly journals Adaptive Reservation of Network Resources According to Video Classification Scenes

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1949
Author(s):  
Lukas Sevcik ◽  
Miroslav Voznak
Keyword(s):  
User Satisfaction ◽  
Quality Evaluation ◽  
Spatial Information ◽  
Service Providers ◽  
Video Quality ◽  
Subjective Assessment ◽  
Video Sequences ◽  
Network Resources ◽  
Proposed Model

Video quality evaluation needs a combined approach that includes subjective and objective metrics, testing, and monitoring of the network. This paper deals with the novel approach of mapping quality of service (QoS) to quality of experience (QoE) using QoE metrics to determine user satisfaction limits, and applying QoS tools to provide the minimum QoE expected by users. Our aim was to connect objective estimations of video quality with the subjective estimations. A comprehensive tool for the estimation of the subjective evaluation is proposed. This new idea is based on the evaluation and marking of video sequences using the sentinel flag derived from spatial information (SI) and temporal information (TI) in individual video frames. The authors of this paper created a video database for quality evaluation, and derived SI and TI from each video sequence for classifying the scenes. Video scenes from the database were evaluated by objective and subjective assessment. Based on the results, a new model for prediction of subjective quality is defined and presented in this paper. This quality is predicted using an artificial neural network based on the objective evaluation and the type of video sequences defined by qualitative parameters such as resolution, compression standard, and bitstream. Furthermore, the authors created an optimum mapping function to define the threshold for the variable bitrate setting based on the flag in the video, determining the type of scene in the proposed model. This function allows one to allocate a bitrate dynamically for a particular segment of the scene and maintains the desired quality. Our proposed model can help video service providers with the increasing the comfort of the end users. The variable bitstream ensures consistent video quality and customer satisfaction, while network resources are used effectively. The proposed model can also predict the appropriate bitrate based on the required quality of video sequences, defined using either objective or subjective assessment.

scholarly journals Analysis of the Evacuation Capacity of Parallel Double Running Stairs in Different Merging Form Based on Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Xia-zhong Zheng ◽  
Xue-ling Xie ◽  
Dan Tian ◽  
Jian-lan Zhou ◽  
Ming Zhang
Keyword(s):  
Computer Simulation ◽  
Evaluation Model ◽  
Pedestrian Flow ◽  
Agent Based Model ◽  
Evacuation Time ◽  
Agent Based ◽  
Positive Correlation ◽  
Model Based ◽  
Evacuation Model ◽  
Merging Behavior

In order to analyze the evacuation capacity of parallel double running stairs, a dozen stairs merging forms are set by investigation and statistics, and the improved agent-based evacuation model that considers the merging behavior is used to simulate the process of merging and evacuation in the stairs. The stairs evacuation capacity is related to the evacuation time and the robustness of stairs, and the evacuation time can be calculated by using the improved agent-based model based on computer simulation. The robustness of each merging form can be obtained according to the fluctuation degree of evacuation time under the different pedestrian flow. The evaluation model of stairs evacuation capacity is established by fusing the evacuation time and the robustness of stairs. Combined with the specific example to calculate the evacuation capacity of each stairs form, it is found that every merging form has different evacuation time and different robustness, and the evacuation time has not positive correlation with the robustness for the same form stairs. Meanwhile, the evacuation capacity of stairs is not related to the number of the floor entrances. Finally, the results show that the evacuation capacity of stairs is optimal when the floor entrances are close to out stairs in parallel double running stairs and suitable to the case where pedestrian flow and the change of pedestrian flow are large.

Experimental Evaluation on Corner Accuracy in WEDM for Aluminium 6061 Alloy

2021 ◽  
pp. 96-113
Author(s):  
Debal Pramanik ◽  
Dipankar Bose
Keyword(s):  
Electrical Discharge ◽  
Thermal Process ◽  
Electrical Discharge Machining ◽  
Sharp Corner ◽  
Proposed Model ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time ◽  
Wire Feed ◽  
Time Pulse

An important electro-thermal process known as wire electrical discharge machining (WEDM) is applied for machining of conductive materials to generate most precisely. All cutting inaccuracies of WEDM arise out of the major cause of wire bending. At the time of cutting a sharp corner or cut profile, bending of the wire leads to a geometrical error on the workpiece. Though this type of error may be of a few hundred microns, it is not suitable for micro applications. In this research study, an experimental investigation based on response surface methodology (RSM) has been done on wire EDM of Aluminium 6061 t6 alloy. This chapter studies the outcome of input process variables (i.e., wire feed rate, pulse on time, pulse off time, and gap voltage) on machining output responses (i.e., corner inaccuracy) extensively. Experimental validation of the proposed model shows that corner inaccuracy value may be reduced by modification of input parameters.

The Influence of Evacuation Signs on Evacuation for Bad Visibility

2014 ◽  
Vol 472 ◽  
pp. 574-578 ◽  
Author(s):  
Hai Tao Chen ◽  
Peng Yang ◽  
Run Cang Yu
Keyword(s):  
Programming Language ◽  
The Novel ◽  
Evacuation Time ◽  
Time Ratio ◽  
Pedestrian Evacuation ◽  
Calculation Results ◽  
Evacuation Model ◽  
Theoretical Results

In emergencies such as fire, pedestrian evacuation for bad visibility is significantly different to the evacuation for normal visibility. In the novel evacuation model, the strategies of pedestrian evacuation and the moving rules are proposed. Then the formulas of the evacuation time are achieved and the time ratio is 0.63. More, using the programming language, pedestrian evacuation is simulated and reproduced. The studies shows that the proposed evacuation model can well reflect the process of pedestrian evacuation; and the evacuation signs of reasonable design can significantly optimize the process. The calculation results also show that the ratio of evacuation time between considering evacuation signs and no evacuation signs is close to 0.63 that is the theoretical results.

Macroscopic Modeling of Pedestrian Flow Considering the Herd Behavior

2013 ◽  
Vol 444-445 ◽  
pp. 906-911
Author(s):  
Yan Qun Jiang
Keyword(s):  
Numerical Experiments ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Behavioral Characteristics ◽  
Herd Behavior ◽  
Pedestrian Flow ◽  
Evacuation Time ◽  
Macroscopic Modeling ◽  
Pedestrian Simulation ◽  
Mass Conservation Equation

This paper aims to mimic the herd behavior of pedestrian flow, i.e., the tendency towards majority when a congestion occurs, by macroscopic modeling approach. The macroscopic pedestrian simulation model is composed of a mass-conservation equation and a simple model to reflect behavioral characteristics of pedestrians based on a specific traffic situation. Numerical experiments are designed to show some preliminary results, e.g. the beneficial effect of herding on evacuation time in some situations.

scholarly journals Reduced-complexity representation of the human arm active endpoint stiffness for supervisory control of remote manipulation

2017 ◽  
Vol 37 (1) ◽  
pp. 155-167 ◽  
Author(s):  
Arash Ajoudani ◽  
Cheng Fang ◽  
Nikos Tsagarakis ◽  
Antonio Bicchi
Keyword(s):  
Robotic Arm ◽  
Model Parameters ◽  
Time Model ◽  
Remote Manipulation ◽  
Proposed Model ◽  
Human Arm ◽  
Human Motor ◽  
Reduced Complexity ◽  
Stiffness Profile ◽  
Endpoint Stiffness

In this paper, a reduced-complexity model of the human arm endpoint stiffness is introduced and experimentally evaluated for the teleimpedance control of a compliant robotic arm. The modeling of the human arm endpoint stiffness behavior is inspired by human motor control principles on the predominant use of the arm configuration in directional adjustments of the endpoint stiffness profile, and the synergistic effect of muscular activations, which contributes to a coordinated modification of the task stiffness in all Cartesian directions. Calibration and identification of the model parameters are carried out experimentally, using perturbation-based arm endpoint stiffness measurements in different arm configurations and cocontraction levels of the chosen muscles. Consequently, the real-time model is used for the remote control of a compliant robotic arm while executing a drilling task, a representative example of tool use in environments with constraints and dynamic uncertainties. The results of this study illustrate that the proposed model enables the master to execute the remote task by modulation of the directions of the major axes of the endpoint stiffness ellipsoid and its volume using natural arm configurations and the cocontraction of the involved muscles, respectively.

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