Simplest Flow Queuing Models for LEO Satellite System

The relevance of the work is associated with the active deployment of low-orbit communication systems and the expansion of research in the field of corresponding satellite systems. A promising low-orbit communication system based on relay satellites with the function (RSRFs) of routing message packets is considered. The low earth orbit communications systems use the BGP protocol and the AAA functionality at the ground station. For assessing the characteristics of RSRF inter-satellite paths, a scenario was created for the message packets arrival from a group of inter-satellite paths to one subscriber path. The corresponding analytical models have been developed using the mathematical apparatus of queuing systems with the simplest flows of requests and exponential distribution of the service time. The RSRF characteristics of a promising low-orbit communication system are predicted. It is proposed to make the mathematical apparatus of analytical models more complicated to take into account the dynamics of displacements and failures of the RSRF in a low-orbit communication system.

Extension of Aspiration Level Model for Optimal Planning of Fast Charging Stations

Electric vehicles will play a dominant role in future transportation due to their friendliness towards the present day environment. The battery which drives the vehicle can be refilled using battery charging and battery swapping techniques. Fast charging stations provide faster service to the customers. Though battery swapping method outperforms battery charging in many ways, the heavy infrastructure requirement of the former requires time in integrating with the real world. Queuing models are used to depict the real-time behavior of service stations. The aspiration level model provides the optimal value of charging piles for the given system capacity in a fast-charging station. The parameters in the aspiration level model can be formulated to an optimization problem. In the present work, the optimal planning for an fast charging station in Beijing is carried out using genetic algorithm. The simulation work is carried out in MATLAB/Simulink.

Construction and Analysis of Queuing and Reliability Models Using Random Graphs

In this paper, the use of the construction of random processes on graphs allows us to expand the models of the theory of queuing and reliability by constructing. These problems are important because the emphasis on the legal component largely determines functioning of these models. The considered models are reliability and queuing. Reliability models arranged according to the modular principle and reliability networks in the form of planar graphs. The queuing models considered here are queuing networks with multi server nodes and failures, changing the parameters of the queuing system in a random environment with absorbing states, and the process of growth of a random network. This is determined by the possibility of using, as traditional probability methods, mathematical logic theorems, geometric images of a queuing network, dual graphs to planar graphs, and a solution to the Dirichlet problem.

Hospital selection in emergency medical service systems: A literature review

Emergency medical service (EMS) systems play a fundamental role in society by providing a vital service in initial emergency care. The purpose of this research is to present the first literature review of hospital selection operational decision within the context of the EMS system. The main findings were the following: The hospital selection problem is integrated with the location, dispatch, routing, and size of the ambulance fleet. The main selection criteria were closeness, hospital care capacities and the shortest queue or greatest number of free beds. The most used performance measures were the shortest transport and waiting time. Solution techniques include discrete event simulation, queuing models, mixed linear integer programming, and CPLEX and Arena software. The application of metaheuristics is scarce; mobile applications and Internet information systems have been implemented for real-time decision making. It is recommended that the design of hospital selection methods be implemented as well as the technological developments, considering the participation of the actors of the EMS system.

Hospital selection in emergency medical service systems: A literature review

Emergency medical service (EMS) systems play a fundamental role in society by providing a vital service in initial emergency care. The purpose of this research is to present the first literature review of hospital selection operational decision within the context of the EMS system. The main findings were the following: The hospital selection problem is integrated with the location, dispatch, routing, and size of the ambulance fleet. The main selection criteria were closeness, hospital care capacities and the shortest queue or greatest number of free beds. The most used performance measures were the shortest transport and waiting time. Solution techniques include discrete event simulation, queuing models, mixed linear integer programming, and CPLEX and Arena software. The application of metaheuristics is scarce; mobile applications and Internet information systems have been implemented for real-time decision making. It is recommended that the design of hospital selection methods be implemented as well as the technological developments, considering the participation of the actors of the EMS system.