Browsing by Author "Lin, Yuan"

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    Bat swarming as an inspiration for multi-agent systems: predation success, active sensing, and collision avoidance
    Lin, Yuan (Virginia Tech, 2016-02-22)
    Many species of bats primarily use echolocation, a type of active sensing wherein bats emit ultrasonic pulses and listen to echoes, for guidance and navigation. Swarms of such bats are a unique type of multi-agent systems that feature bats's echolocation and flight behaviors. In the work of this dissertation, we used bat swarming as an inspiration for multi-agent systems to study various topics which include predation success, active sensing, and collision avoidance. To investigate the predation success, we modeled a group of bats hunting a number of collectively behaving prey. The modeling results demonstrated the benefit of localized grouping of prey in avoiding predation by bats. In the topics regarding active sensing and collision avoidance, we studied individual behavior in swarms as bats could potentially benefit from information sharing while suffering from frequency jamming, i.e., bats having difficulty in distinguishing between self and peers's information. We conducted field experiments in a cave and found that individual bat increased biosonar output as swarm size increased. The experimental finding indicated that individual bat acquired more sensory information in larger swarms even though there could be frequency jamming risk. In a simulation wherein we modeled bats flying through a tunnel, we showed the increasing collision risk in larger swarms for bats either sharing information or flying independently. Thus, we hypothesized that individual bat increased pulse emissions for more sensory information for collision avoidance while possibly taking advantage of information sharing and coping with frequency jamming during swarming.
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    Cooperative Adaptive Cruise Control With Adaptive Kalman Filter Subject to Temporary Communication Loss
    Wu, Chaoxian; Lin, Yuan; Eskandarian, Azim (IEEE, 2019)
    Cooperative adaptive cruise control (CACC) communicates the relevant preceding vehicle state data to the follower (ego) vehicle to improve the vehicle following capabilities. In general, the CACC utilizes the preceding vehicle's desired acceleration from wireless communication as a feedforward term in the controller of the ego vehicle, which dominantly determines the total control input. However, communication loss would degrade CACC to adaptive cruise control (ACC), where the lack of the feedforward term during communication loss would increase the inter-vehicular distance or, otherwise, may lead to collision during vehicle emergency braking. This paper proposes a control algorithm with an adaptive Kalman filter estimating the acceleration of a preceding vehicle, and the estimated acceleration is implemented as a feedforward signal in the ego-vehicle CACC controller in case of communication loss. The proposed control algorithm is evaluated by the experiments using mobile robots that emulate driving. In addition, the simulations of real vehicles are also conducted. The results of simulations and robot experiments show that the performance of implementing the adaptive Kalman filter during communication loss is better than fallback to ACC and the normal Kalman filter based on the Singer model.
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    Plant-Produced Asialo-Erythropoietin Restores Pancreatic Beta-Cell Function by Suppressing Mammalian Sterile-20-like Kinase (MST1) and Caspase-3 Activation
    Arthur, Elena; Kittur, Farooqahmed S.; Lin, Yuan; Hung, Chiu-Yueh; Sane, David C.; Xie, Jiahua (Frontiers, 2017-04-19)
    Pancreatic beta-cell death adversely contributes to the progression of both type I and II diabetes by undermining beta-cell mass and subsequently diminishing endogenous insulin production. Therapeutics to impede or even reverse the apoptosis and dysfunction of beta-cells are urgently needed. Asialo-rhuEPO, an enzymatically desialylated form of recombinant human erythropoietin (rhuEPO), has been shown to have cardioprotective and neuroprotective functions but with no adverse effects like that of sialylated rhuEPO. Heretofore, the anti-apoptotic effect of asialo-rhuEPO on pancreatic beta-cells has not been reported. In the current study, we investigated the cytoprotective properties of plant-produced asialo-rhuEPO (asialo-rhuEPO(P)) against staurosporine-induced cell death in the pancreatic beta-cell line RIN-m5F. Our results showed that 60 IU/ml asialo-rhuEPO(P) provided 41% cytoprotection while 60 IU/ml rhuEPO yielded no effect. Western blotting results showed that asialo-rhuEPO(P) treatment inhibited both MST1 and caspase-3 activation with the retention of PDX1 and insulin levels close to untreated control cells. Our study provides the first evidence indicating that asialo-rhuEPO(P)-mediated protection involves the reduction of MST1 activation, which is considered a key mediator of apoptotic signaling in beta-cells. Considering the many advantages its plant-based expression, asialo-rhuEPO(P) could be potentially developed as a novel and inexpensive agent to treat or prevent diabetes after further performing studies in cell-based and animal models of diabetes.