Analysis of the Impact of Decreasing the Width of Direct Stairs in Apartments on RSET for All Occupants in Korea

This study analyzed the RSETs for 11-story or less apartments where the building-related laws were not retroactively applied, with consideration of the decrease of direct stairs width due to obstacles piled up on the direct stairs. The RSET was shown to be 631.8 seconds when the width of the direct stairs was 1,260mm. The evacuation time exceeded 5 minutes even when there were no obstacles due to the delayed evacuation start time. The risk increased when the width of the direct stairs was decreased to 960mm, 760mm, and 560mm because of obstacles, and the RSETs were 768.8 seconds, 803.3 seconds, and 834.4 seconds respectively. There are various ways to eliminate the occurrence of obstacles on direct stairs which increase RSET : First, it is necessary to remove the exception that permits the placement of obstacles on the stairs. Second, penalties for the placement of obstacles on the direct stairs should be enforced as written. Third, the fire safety managers need the authority to act on behalf of the fire officials. Lastly, it is necessary to encourage residents to report instances of obstacle accumulation. Henceforth, more research is needed on the spread speed of smoke and toxic gases depending on whether fire doors are installed through fire simulation.

A stochastic approach to number of corona virus cases

This paper introduces a stochastic approach to case numbers of a pandemic disease. By defining the stochastic process random walk process is used. Some stochastic aspects for this disease are argued before stochastic study is started. During random walk process modeling new patients, recovering patients and dead conclusions are modelled and probabilities changes in some stages. Let the structure of this study includes vanishing process as a walk step, some wave happenings like big differences about spread speed as a big step in treatment- an effective vaccine or an influential chemical usage- a second corona virus pumping with virus mutation, a second global happening which bumping virus spread are defined as stages. This study only simulates a stochastic process of corona virus effects.

When Robots contribute to eradicate the COVID-19 spread in a context of containment

In the era of autonomous robots, multi-targets search methods inspired researchers to develop adapted algorithms to robot constraints, and with the rising of Swarm Intelligence (SI) approaches, Swarm Robotics (SRs) became a very popular topic. In this paper, the problem of searching for an exponentially increasing number of targets in a complex and unknown environment is addressed. Our main objective is to propose a Robotic target search strategy based on the EHO (Elephants Herding Optimization) algorithm, namely Robotic-EHO (REHO). The main additions were the collision-free path planning strategy, the velocity limitation, and the extension to the multi-target version in discrete environments. The proposed method has been the subject of many experiments, emulating the search of infected individuals by COVID-19 in a context of containment within complex and unknown random environments, as well as in the real case study of USA. The particularity of these environments is their increasing targets' number and the dynamic Containment Rate (CR) that we propose. The experimental results show that REHO reacts much better in high Containment Rate, early start search mission, and where the robots' speed is higher than the virus spread speed.

Characteristics of and Public Health Emergency Responses to COVID-19 and H1N1 Outbreaks: A Case-Comparison Study

Background: Recently, the novel coronavirus disease (COVID-19) has already spread rapidly as a global pandemic, just like the H1N1 swine influenza in 2009. Evidences have indicated that the efficiency of emergency response was considered crucial to curb the spread of the emerging infectious disease. However, studies of COVID-19 on this topic are relatively few. Methods: A qualitative comparative study was conducted to compare the timeline of emergency responses to H1N1 (2009) and COVID-19, by using a set of six key time nodes selected from international literature. Besides, we also explored the spread speed and peak time of COVID-19 and H1N1 swine influenza by comparing the confirmed cases in the same time interval. Results: The government’s entire emergency responses to the epidemic, H1N1 swine influenza (2009) completed in 28 days, and COVID-19 (2019) completed in 46 days. Emergency responses speed for H1N1 was 18 days faster. As for the epidemic spread speed, the peak time of H1N1 came about 4 weeks later than that of COVID-19, and the H1N1 curve in America was flatter than COVID-19 in China within the first four months after the disease emerged. Conclusions: The speed of the emergency responses to H1N1 was faster than COVID-19, which might be an important influential factor for slowing down the arrival of the peak time at the beginning of the epidemic. Although COVID-19 in China is coming to an end, the government should improve the public health emergency system, in order to control the spread of the epidemic and lessen the adverse social effects in possible future outbreaks.

Multi-message topic dissemination probabilistic model with memory attenuation based on Social–Messages Network

Current researches give priority to the diffusion of single message, but the diffusion of multi-messages at the same time in the actual network also exists. The diverse correlation of the messages will influence each other in the diffusion. It should be taken into consideration. This paper works to make a definition to the framework of Social–Messages Network. Based on it, a multi-message topic dissemination probabilistic model with memory attenuation is put forward, which introduces the correlation among messages. We adopt a simple learning strategy to gain the diverse correlation of messages. Then, the numerical simulation is utilized to analyze the model, whilst the relationship of the model parameter with the scope of the topic diffusion and the spread speed are studied and analyzed. With the related discussion data on Twitter, an empirical study is made to the model and the diffusion progress of the message is anticipated, which suggested that the anticipation is fundamentally in line with the actual data, and the estimated value of our model is closer to the reality than the classic diffusion model. Study on the topic diffusion will be conducive to the understanding and the anticipation of the multi–messages spread.

Accident at river-crossing underwater oil pipeline

The aim of this article is to present an approach enabling to define the flame spread velocity at spill fire on the river, taking into account the wind speed. Due to constant oil supply from the pipeline during the leakage, an oil slick will increase until its borders reach river banks. Formulas for determining the main parameters of oil spill on the river in case of an accident at underwater oil pipeline were suggested. The formulas include the initial data determined in the field, for instance, flow and wind speed, as well as water temperature. An example of the change of oil slick parameters on the river was demonstrated. The spread rate of spilled oil and the flame spread speed were calculated. It was shown that on narrow rivers, an oil slick takes the form of a river bed within a few minutes and moves in the direction of the flow. Determination of oil spill parameters given in the study is sufficient for accident response implementation: - spread rate of spilled oil allows for distance calculation in order to install oil booms; - flame spread speed in conjunction with the oil slick size will make it possible to calculate the fire extinguishing means. The obtained results, undoubtedly, require testing in experimental conditions, which is the purpose of further research.