Simulation Analyses of End-Around Taxiway Operations under Four Different Runway and Taxiway Choices

Author(s):  
Yilin Feng ◽  
Mary E. Johnson

End-around taxiways (EAT) have been implemented at four major U.S. airports to increase the safety and throughput of parallel runway systems. This paper proposes two new runway and taxiway choices that become possible because of EATs. Instead of using the inboard runway to take off, the departing aircraft could use the outboard runway and use the EAT as the taxi-out path. A discrete-event stochastic simulation model simulates the operations of four different runway and taxiway choices. Two experiments compare the performance of the four choices on average taxi times, average fuel consumption per taxi, and number of runway crossings. In general, the results indicate that using the outboard runway to take off and the EAT as a taxi-out path would yield benefits in both taxi-in and taxi-out performance, as well as enhancing runway safety. Using the outboard runway to land and the EAT as a taxi-in path would yield benefit in taxi-out performance and runway safety at the expense of a longer taxi-in time. Concerns related to using the EAT as the taxi-out path, as well as potential future research topics, are discussed.

Author(s):  
Yuri Merkuryev ◽  
Vladimir Bardachenko ◽  
Andrey Solomennikov

Simulation of Pessimism Influence on Choice of Farming Strategy under Uncertainty Weather-related risks can substantially affect the crop volume depending on time and intensity of agricultural operations performed by the farmer. However, decisions under uncertainty are in some way also liable to another risk - that of excessively optimistic or pessimistic estimation of the decision maker. The paper presents results of optimistic and pessimistic farmer's agricultural operations efficiency based on the analysis of the developed discrete-event stochastic simulation model. The aim of the model is to obtain quantitative estimation of optimistic and pessimistic farmer's choice of agricultural operation strategy efficiency under fluctuation of weather conditions.


2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.


animal ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 145-154 ◽  
Author(s):  
P.F. Mostert ◽  
E.A.M. Bokkers ◽  
C.E. van Middelaar ◽  
H. Hogeveen ◽  
I.J.M. de Boer

Author(s):  
Anuj Srivastava

This article develops an agent-level stochastic simulation model, termed RAW-ALPS, for simulating the spread of an epidemic in a community. The mechanism of transmission is agent-to-agent contact, using parameters reported for the COVID-19 pandemic. When unconstrained, the agents follow independent random walks and catch infections due to physical proximity with infected agents. Under lockdown, an infected agent can only infect a coinhabitant, leading to a reduction in the spread. The main goal of the RAW-ALPS simulation is to help quantify the effects of preventive measures—timing and durations of lockdowns—on infections, fatalities, and recoveries. The model helps measure changes in infection rates and casualties due to the imposition and maintenance of restrictive measures. It considers three types of lockdowns: 1) whole population (except the essential workers), 2) only the infected agents, and 3) only the symptomatic agents. The results show that the most effective use of lockdown measures is when all infected agents, including both symptomatic and asymptomatic, are quarantined, while the uninfected agents are allowed to move freely. This result calls for regular and extensive testing of a population to isolate and restrict all infected agents.


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