Reducing casualties and property losses through effective evacuation route planning has been a key focus for researchers in recent years.As part of this effort, an enhanced sparrow search algorithm (MSSA) was proposed.Firstly, the Golden Sine nonlinear weight factor optimization strategy were added discoverer position update stage SSA algorithm.Secondly, Cauchy-Gaussian perturbation applied to optimal improve its ability jump out local optima.Finally, mechanism based on mountain climbing...

Intersecting pedestrian flows especially multi-directional ones are complicated in dynamics. People will face unavoidable head-on conflicts and obstruct each other. In this paper, controlled experiments of a four-directional intersecting flow were conducted. Up to 364 university students took part the their trajectories extracted by mean-shift algorithm. The global density–velocity relations cross area different scenarios compared. Moreover, local density-flow investigated. order adapt study...

Satellite remote sensing provides global observations of the Earth’s surface and useful information for monitoring smoke plumes emitted from forest fires. The aim this study is to automatically separate background by analyzing MODIS data. An identification algorithm was improved based on spectral analysis among smoke, cloud underlying surface. In order get satisfactory results, a multi-threshold method used extracting training sample sets train back-propagation neural network (BPNN)...

Underground coalbed methane extraction is an important way for preventing coal mine gas disasters and reducing greenhouse emission, but air leakage around boreholes a critical factor that limits efficient extraction. Dynamically filling plugging fractures can prevent leakage. Due to the invisibility complexity of underground geological formations, observing process effectiveness extremely challenging. To visualize quantitatively characterize performances in coal. First, experiments are...

Current research on pedestrian dynamics mainly focuses the interactions among isolated individuals, impact of presence groups is not fully considered. In recent 5 years, researchers have started to investigate group movement. The aim this work explore local behavior by questionnaires and field observation. Survey study focused pedestrians' psychology when walking in groups, which included five parts: size, interpersonal distance, spatial relationship members, speed adjustment information...

In the face of fire in buildings, people need to quickly plan their escape routes. Intelligent optimization algorithms can achieve this goal, including sparrow search algorithm (SSA). Despite powerful ability SSA, there are still some areas that improvements. Aiming at problem reduces population diversity and is easy fall into local optimum when solving optimal solution objective function, a hybrid improved proposed. First, logistic-tent mapping used initialize enhance population. Also, an...

In this study, while aiming at the prevention of fire accidents in underground commercial streets, an street is selected as a research object, and building numerically simulated using PyroSim software. Fire simulation scenarios are divided according to different zones by analyzing temperature, carbon monoxide (CO) concentration, visibility smoke layer inside building. The available safe evacuation time calculated critical hazard judgment conditions. We found that when flue gas temperature CO...

The research of human crowd dynamic is significant for the building designers and emergency guiders. However, current researches mainly focus on interactions among isolated individuals, influence social pedestrian needed to take into consideration in study. In this manuscript we carried out observed experiments movement group used optical flow algorithm extract pedestrian's trajectory from video. Then characteristics members were analyzed discussed, which include angle, distance, velocity,...

In this paper, a simple velocity-headway relation is used to describe the pedestrian following behavior in single-file passageway. Single-file movement experiment was conducted obtain distance headway-velocity data and nonlinear curve fitting are executed gain good form of equation. Referring ideas car-following models, velocity- headway as fundamental optimal velocity function then we adopts model study behavior. Linear stability analyses give phase diagram headway-sensitivity....

In this study, a very basic experiment of single-file bicycles moving in circle passage was conducted. A video processing method used to extract the relevant data such as trajectories, velocity, density, flow rate, time headway and so on. Afterwards, relations between them were explained detail. The relation rate density indicated that is proportion with before congestion appears. It also found interval two long but decreased increased when can move freely, while situation opposite occurs....

To thoroughly study the extinguishing effect of a high-pressure water mist fire system when transformer occurs, 3D experimental model is established in this work by employing Fire Dynamics Simulator (FDS) software. More specifically, setting different parameters, process with presence both diverse ambient temperatures and sprinkler laying conditions simulated. In addition, employed implementation strategies systematically analyzed. The extracted results show that source farther away from...

Abstract Emergency rescue is an important measure to save people's lives and reduce the loss. Choosing effective route has a great effect on process. In previous research, planning routes were usually chosen in advance little attention was paid unexpected accident happened road network during Under condition of accident, whether change which choose are crucial for work. this paper, we concentrate problem use modified Dijistra algorithm obtain time-shortest network. Moreover give simple...

Recently trample and other disasters concerning mass crowd frequently happened in public places the evacuation safety draws whole society's attention. Hospital is such a special place that study on it rare. So this paper chooses hospital as object of resets velocity pedestrians software FDS+Evac by means collecting data related to real velocities different pedestrian groups hospital, investigates how parameters exit familiarity influence results. The results show large difference leads...

Fire accidents due to oil-immersed transformers seriously threaten the safe operation of power systems. In this paper, similarity principle was used design a high-pressure water mist fire-extinguishing test platform for small-scale transformer fire, and method achieved good fire extinguishing effect. The results indicate that deflagration phenomenon, lasting about 2–4 s, could be observed after activating system; flame temperature rose rapidly at first, then dropped sharply, finally cooled...

In the context of a fire emergency, safe and efficient exits are paramount importance for pedestrian evacuation. The recent rapid development in construction industry has rendered exit structures more diverse complex. However, little attention been paid to influence on efficiency crowd evacuation processes. this paper, tentative experiment was designed preliminarily reveal effects five (Exit 1, Exit 2, 4, 5, 3 as examples comparison) 1 door leaves opening outward. 2 inward. no leaves. 4...

In order to cope with limited land availability and the increasing urban population, more high-rise buildings are being built throughout cities, but this has also led new challenges in emergency evacuation of people. Therefore, we conducted an experiment a group people stairwells explore movement law groups stairwells. The had 18 scenes, including independent crowd different groups. Analyzing groups’ showed that regardless type group, average speed was than 1.2 m/s, which longer previous...

The combustion of lithium-ion batteries is characterized by fast ignition, prolonged duration, high temperature, release significant energy, and generation a large number toxic gases. Fine water mist has characteristics such as fire extinguishing efficiency environmental friendliness. In order to thoroughly investigate the temperature control effect fine on battery fires. This study employs numerical simulation methods, utilizing PyroSim software simulate process in energy storage...

The ceiling structure in a long-narrow space has significant impact on the thickness of fire smoke layer. This paper mainly studies influence height layer before structure. Firstly, theoretical analysis is conducted relationship between critical that affects flow state and directly below structure, formula for calculating under gradient conditions derived. Then small-scale experimental platform was built to study deviation actual relative calculations. Experimental results show due cannot...

In order to study the influence of wind direction on fire spread building facades, a three-dimensional model high-rise was built with PyroSim software. Numerical simulations were conducted five directions (0°, 45°, 90°, 135° and 180°) reference speed 3 m/s. The results show that facade most significant leeward side, followed by upwind condition. horizontal promoted crosswinds at 90° 135°, while its vertical inhibited. Among these, inhibitory effect 45° crosswind greatest. area under...