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1. A path planning algorithm for human evacuations with an environment dependent motion

   https://doi.org/10.1109/CDC40024.2019.9028931  

   Demetriou, Michael A.; Kontopyrgos, Marios (December 2019, 2019 IEEE 58th Conference on Decision and Control (CDC))

   This work proposes an algorithm for the optimal guidance of evacuees in indoor environments. The proposed work examines the path-dependent accumulation of hazardous substances inhaled, such as carbon monoxide, and provides an optimal path that ensures that evacuees can survive to emergency exits by guaranteeing the accumulated inhalation of carbon monoxide is below life-threatening levels. The spatiotemporal variation of the hazardous and toxic field, as described by either Poisson or advection-diffusion partial differential equation, is used to compute the accumulated amount of carbon monoxide inhaled. The accumulated amount is given in terms of the line integral of the hazardous field along the escape paths. The effects of carbon monoxide on evacuee speed are considered. To ensure a path with lower carbon monoxide inhalation levels as well as reduced flight times, level sets are used to generate the set of angles for each path. This is done using a coefficient that changes the direction of motion based on the instantaneous carbon monoxide concentration. This coefficient varies based on the level set with a specific critical level set declared such that it is never crossed. The optimization scheme provides the optimal path among all admissible paths having the smallest value below the tolerance levels of the substance. Simulation studies considering both spatially and spatiotemporally varying functions of carbon monoxide in an indoor environment representing a floor of an office building, are provided to further demonstrate evacuation policies in contaminated indoor environments. 

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2. A Psychological Approach for the Path Planning of Human Evacuations in Contaminated Indoor Environments

   Amanda C. Dings, Constantina M. (July 2020, 21st IFAC World Congress)

   This work considers a level-set based algorithm for guiding evacuees in indoor environments. The algorithm considers the accumulated inhalation of a hazardous substance such as carbon monoxide and attempts to provide an optimal path to ensure survivability. The algorithm also considers psychological decision making of evacuees. The most significant psychological contribution to overall evacuation time is the tendency of evacuees to underreact, causing decision making delays. During an emergency, evacuees with high risk perception will be directly incentivized to make evacuation decisions, while those with low risk perception will likely continue to delay decision making. This work models this phenomenon by simulating an initial accumulated concentration before the evacuee begins moving. Earlier work has shown that level-set based paths are much more likely to lead an evacuee to safety than a constant angle path, because they ensure the evacuee’s peak exposure to the hazardous substance remains low. After including the psychological delay, this work supports these results. Additionally, a higher initial concentration (i.e. a longer psychological delay) decreases the chances of survival more significantly than does a higher instantaneous concentration of the field itself. 

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3. Optimal navigation over spatiotemporally varying hazardous fields

   https://doi.org/10.1109/CDC45484.2021.9682802  

   Demetriou, Michael A.; Bakolas, Efstathios (December 2021, 2021 60th IEEE Conference on Decision and Control)

   This paper considers the optimal navigation problem wherein the agent has to traverse a spatiotemporally varying hazardous field that has severely lethal effects on the agent. The accumulated effects of the value of the spatiotemporally varying field along the path, represented by the line integral of the spatial field along the chosen trajectory, constitutes the destructive effects of the hazardous field. When this accumulated amount exceeds a prescribed threshold, the agent is incapacitated and can no longer move. We formulate the navigation problem as an optimal control problem in which the agent has to traverse a 2D enclosed domain and reach its goal destination at a free final time while minimizing the cumulative exposure to the hazardous field. Due to practical considerations, the solution to the optimal control problem is admissible only if the accumulated exposure of the agent when it reaches the final destination is well below the deadly threshold. The evolution of the spatiotemporally varying field is described by a 2D advection-diffusion PDE with a moving source that realistically captures rapidly evolving hazardous fields. Extensive numerical studies are included to highlight the various aspects of the proposed constrained navigation problem. 

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4. Quantitative Analysis of Honey Bee Blood-Ethanol Levels Following Exposure to Ethanol Vapors

   https://doi.org/10.46867/ijcp.25002  

   Stauch, Kiri; LeBlanc, Gabriel; Wells, Harrington; Wincheski, Riley; Grossner, Laura M; Abramson, Charles I (January 2025, International Journal of Comparative Psychology)

   The use of invertebrate models has allowed researchers to examine the mechanisms behind alcoholism and its effects with a cost-effective system. In that respect, the honey bee is an ideal model species to study the effects of ethanol (EtOH) due to the behavioral and physiological similarities of honey bees with humans when alcohol is consumed. Although both ingestion and inhalation methods are used to dose subjects in insect EtOH model systems, there is little literature on the use of the EtOH vapor-exposure method for experiments using honey bees. The experiment presented here provides baseline data for a dose EtOH-hemolymph response curve when using EtOH vapor-inhalation dosing with honey bees (Apis mellifera). Bees were exposed to EtOH vapors for 0, 1, 2.5, or 5 min, and hemolymph was collected 1 min post EtOH exposure. Hemolymph samples were analyzed using gas chromatography (GC) for hemolymph EtOH concentration. The ethanol-hemolymph level of the bees increased linearly with exposure time. The results provide a dosing guide for hemolymph EtOH level in the honey bee model ethanol-inhalation system, and thus makes the honey bee model more robust. 

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5. Synergistic AUV Navigation through Deployed Surface Buoys

   https://doi.org/10.1109/IRC.2020.00020  

   Alam, Tauhidul; Gandy, Logan; Bobadilla, Leonardo; Smith, Ryan N. (November 2020, 2020 Fourth IEEE International Conference on Robotic Computing (IRC))

   null (Ed.)

   In this paper, we present a navigation method for an Autonomous Underwater Vehicle (AUV) in an underwater environment making use of a deployed set of static water surface platforms called buoys on the environment. Our method has the following steps: 1) Communication regions of buoys are computed from their communication capabilities; 2) A set of feasible paths through buoys between given initial and goal locations is calculated using the preimages of the buoys' communication regions; 3) An AUV navigation path that utilizes the least number of buoys for state estimation is chosen from the calculated feasible paths. Through extensive simulations, we validated our method which demonstrates its applicability. 

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