A New Fractional Order Dynamic Model for Human Crowd Stampede System

2015 ◽  
Author(s):  
Ke-Cai Cao ◽  
YangQuan Chen ◽  
Dan Stuart
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Collective Behavior ◽  
Modeling Framework ◽  
Evacuation Time ◽  
Microscopic Scale ◽  
Long Range Interactions ◽  
Dynamic Description ◽  
Human Crowd ◽  
Pedestrian System

Tragedies due to people’s crushing or trampling have been observed in recent years. In order to understand the reasons that lead to these accidents, a lot of research has been conducted in modeling or predicting the behavior of crowd pedestrians. A new kind of fractional order dynamic description for crowd-pedestrian system has been developed in microscopic scale in this paper for a better understanding of human collective behavior where fractional order in time domain has been introduced. Due to the freedom provided by Fractional Calculus, a lot of characters of pedestrians can be considered in this fractional order modeling framework, such as memory effects, long range interactions and heterogeneity of each individual. Simulations results using Matlab in microscopic are also presented to show the effects of integer order and fractional order on evacuation time which is useful in evaluating the evacuation process or predicting crowd stampede that is going to occur.

scholarly journals Social Collective Attack Model and Procedures for Large-Scale Cyber-Physical Systems

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 991
Author(s):  
Peidong Zhu ◽  
Peng Xun ◽  
Yifan Hu ◽  
Yinqiao Xiong
Keyword(s):  
Smart Grid ◽  
Collective Behavior ◽  
Physical System ◽  
Large Scale ◽  
Public Utility ◽  
Modeling Framework ◽  
Vast Number ◽  
Attack Model ◽  
The Social ◽  
Social Collective

A large-scale Cyber-Physical System (CPS) such as a smart grid usually provides service to a vast number of users as a public utility. Security is one of the most vital aspects in such critical infrastructures. The existing CPS security usually considers the attack from the information domain to the physical domain, such as injecting false data to damage sensing. Social Collective Attack on CPS (SCAC) is proposed as a new kind of attack that intrudes into the social domain and manipulates the collective behavior of social users to disrupt the physical subsystem. To provide a systematic description framework for such threats, we extend MITRE ATT&CK, the most used cyber adversary behavior modeling framework, to cover social, cyber, and physical domains. We discuss how the disinformation may be constructed and eventually leads to physical system malfunction through the social-cyber-physical interfaces, and we analyze how the adversaries launch disinformation attacks to better manipulate collective behavior. Finally, simulation analysis of SCAC in a smart grid is provided to demonstrate the possibility of such an attack.

scholarly journals A Comparison of Time-Domain Implementation Methods for Fractional-Order Battery Impedance Models

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4415
Author(s):  
Brian Ospina Agudelo ◽  
Walter Zamboni ◽  
Eric Monmasson
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Li Ion Batteries ◽  
Simulation Framework ◽  
Frequency Range ◽  
Interesting Approach ◽  
Li Ion ◽  
Impedance Parameters ◽  
Impedance Models ◽  
Made In

This paper is a comparative study of the multiple RC, Oustaloup and Grünwald–Letnikov approaches for time domain implementations of fractional-order battery models. The comparisons are made in terms of accuracy, computational burden and suitability for the identification of impedance parameters from time-domain measurements. The study was performed in a simulation framework and focused on a set of ZARC elements, representing the middle frequency range of Li-ion batteries’ impedance. It was found that the multiple RC approach offers the best accuracy–complexity compromise, making it the most interesting approach for real-time battery simulation applications. As for applications requiring the identification of impedance parameters, the Oustaloup approach offers the best compromise between the goodness of the obtained frequency response and the accuracy–complexity requirements.

scholarly journals A microscopic look at the Johari-Goldstein relaxation in a hydrogen-bonded glass-former

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
F. Caporaletti ◽  
S. Capaccioli ◽  
S. Valenti ◽  
M. Mikolasek ◽  
A. I. Chumakov ◽  
...  
Keyword(s):  
Time Domain ◽  
Glassy State ◽  
Center Of Mass ◽  
Relaxation Processes ◽  
Undercooled Liquid ◽  
Microscopic Scale ◽  
Glass Forming ◽  
Full Explanation ◽  
Molecular Scale ◽  
Hydrogen Bonded

Abstract Understanding the glass transition requires getting the picture of the dynamical processes that intervene in it. Glass-forming liquids show a characteristic decoupling of relaxation processes when they are cooled down towards the glassy state. The faster (βJG) process is still under scrutiny, and its full explanation necessitates information at the microscopic scale. To this aim, nuclear γ-resonance time-domain interferometry (TDI) has been utilized to investigate 5-methyl-2-hexanol, a hydrogen-bonded liquid with a pronounced βJG process as measured by dielectric spectroscopy. TDI probes in fact the center-of-mass, molecular dynamics at scattering-vectors corresponding to both inter- and intra-molecular distances. Our measurements demonstrate that, in the undercooled liquid phase, the βJG relaxation can be visualized as a spatially-restricted rearrangement of molecules within the cage of their closest neighbours accompanied by larger excursions which reach out at least the inter-molecular scale and are related to cage-breaking events. In-cage rattling and cage-breaking processes therefore coexist in the βJG relaxation.

scholarly journals A bilinear identification‐modeling framework from time domain data

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Dimitrios S. Karachalios ◽  
Ion Victor Gosea ◽  
Athanasios C. Antoulas
Keyword(s):  
Time Domain ◽  
Modeling Framework ◽  
Time Domain Data

Improving the time domain response of fractional order digital differentiators by windowing

2015 ◽  
Vol 107 ◽  
pp. 282-289 ◽  
Author(s):  
Chengyan Peng ◽  
Xiaochuan Ma ◽  
Geping Lin ◽  
Min Wang
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Time Domain Response ◽  
The Time Domain

scholarly journals Analysis of Flood Evacuation Process in Vulnerable Community with Mutual Aid Mechanism: An Agent-Based Simulation Framework

2020 ◽  
Vol 17 (2) ◽  
pp. 560 ◽  
Author(s):  
Zhiqiang Wang ◽  
Jing Huang ◽  
Huimin Wang ◽  
Jinle Kang ◽  
Weiwei Cao
Keyword(s):  
Urban Communities ◽  
Flood Risk ◽  
Emergency Evacuation ◽  
Risk Tolerance ◽  
Low Density ◽  
Mutual Aid ◽  
Modeling Framework ◽  
Evacuation Time ◽  
Agent Based ◽  
Evacuation Management

Timely and secure evacuation of residents during flood disasters or other emergency events is an important issue in urban community flood risk management, especially in vulnerable communities. An agent-based modeling framework was proposed in order to indicate how the community properties (e.g., community density and percentage of vulnerable residents), residents’ psychological attributes (e.g., flood risk tolerance threshold) and mutual aid mechanism affect the flood evacuation process. Results indicated that: (1) The community density negatively affected the flood evacuation efficiency. The greater the density of the community, the longer the evacuation time. (2) There was a negative correlation between the flood risk tolerance threshold of residents and evacuation efficiency. (3) The proportion of vulnerable resident agents had opposite effects on the evacuation efficiency of different types of communities, which was to negatively affect low-density communities and positively affect high-density communities. (4) Mutual aid mechanism can reduce evacuation time in low-density communities, and the effect was more pronounced with a higher proportion of vulnerable resident agents in the community. These findings can help managers to develop better emergency evacuation management for urban communities.

scholarly journals Time domain diffusion parameters identification of electrochemical impedance models using fractional order system

2018 ◽  
Vol 51 (15) ◽  
pp. 377-382 ◽  
Author(s):  
Achraf Nasser Eddine ◽  
Benoît Huard ◽  
Jean-Denis Gabano ◽  
Thierry Poinot ◽  
Anthony Thomas ◽  
...  
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Electrochemical Impedance ◽  
Parameters Identification ◽  
Fractional Order System ◽  
Order System ◽  
Diffusion Parameters ◽  
Impedance Models
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