235 research outputs found

    Energy-efficient Reactive and Predictive Connected Cruise Control

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    In this paper, we propose a framework for the longitudinal control of connected and automated vehicles traveling in mixed traffic consisting of connected and non-connected human-driven vehicles. Reactive and predictive controllers are proposed. Reactive controllers are given by explicit feedback control laws. In predictive controllers, the control input is optimized in a receding-horizon fashion, which depends on the predictions of motions of preceding vehicles. Beyond-line-of-sight information is obtained via vehicle-to-vehicle (V2V) communication, and is utilized in the proposed reactive and predictive controllers. Simulations utilizing real traffic data are used to show that connectivity can bring significant energy savings.Comment: 18 pages, 12 figures, submitted to Transportation Research Part C: Emerging Technologie

    Opinions of an Iranian nursing faculty on barriers to implementing problem-based learning

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    ABSTRACT We investigated the opinions of all 53 lecturers in the nursing faculty of Tabriz University of Medical Sciences about barriers to implementation of problem-based learning (PBL). A 13-item ques--tionnaire was used which included questions on number and preparedness of students and lecturers, educational space and course content. We found that 95% of the respondents believed that the most important barrier was the students' lack of knowledge and skills in group work and active interaction; 94% also believed that the change in their role from lecturer to facilitator would not reduce their motiva--tion but it could be a potential barrier. The majority (98%) indicated that the cost of implementation and maintenance of PBL, too many students and a shortage of lecturers competent in PBL were among the barriers that needed to be considered. L'avis d'une facultĂ© de soins infirmiers iranienne sur les obstacles Ă  la mise en oeuvre de l'apprentissage par problĂšmes RÉSUMÉ Nous avons sondĂ© l'opinion de l'ensemble des 53 chargĂ©s d'enseignement de la facultĂ© des soins infirmiers de l'UniversitĂ© des Sciences mĂ©dicales de Tabriz sur les obstacles que rencontre la mise en oeuvre de la mĂ©thode d'apprentissage dite problem-based learning (PBL), ou approche par problĂšmes (APP). Pour ce faire, nous avons utilisĂ© un questionnaire en 13 points visant Ă  dĂ©terminer le nombre et l'Ă©tat de prĂ©paration des Ă©tudiants et des chargĂ©s d'enseignement, l'espace pĂ©dagogique et le contenu de l'enseignement. Il nous est apparu que 95 % des personnes interrogĂ©es estiment que l'obstacle primordial rĂ©side dans la carence des connaissances des Ă©tudiants et leurs difficultĂ©s d'adaptation aux mĂ©thodes de travail de groupe et d'interaction active. En outre, 94 % pensent que leur mutation du statut de chargĂ© d'enseignement au rĂŽle d'animateur-formateur ne devrait pas entamer leur motivation, mais qu'elle pourrait Ă©ventuellement ĂȘtre perçue comme un obstacle. La majoritĂ© (98 %) souligne que le coĂ»t de la mise en application de l'APP comme de son maintien, l'effectif trop impor--tant des Ă©tudiants et la pĂ©nurie d'enseignants APP sont autant d'obstacles qu'il convient de ne pas nĂ©gliger

    Zinc modulates several transcription-factor regulated pathways in mouse skeletal muscle cells

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    Zinc is an essential metal ion involved in many biological processes. Studies have shown that zinc can activate several molecules in the insulin signalling pathway and the concomitant uptake of glucose in skeletal muscle cells. However, there is limited information on other potential pathways that zinc can activate in skeletal muscle. Accordingly, this study aimed to identify other zinc-activating pathways in skeletal muscle cells to further delineate the role of this metal ion in cellular processes. Mouse C2C12 skeletal muscle cells were treated with insulin (10 nM), zinc (20 ”M), and the zinc chelator TPEN (various concentrations) over 60 min. Western blots were performed for the zinc-activation of pAkt, pErk, and pCreb. A Cignal 45-Reporter Array that targets 45 signalling pathways was utilised to test the ability of zinc to activate pathways that have not yet been described. Zinc and insulin activated pAkt over 60 min as expected. Moreover, the treatment of C2C12 skeletal muscle cells with TPEN reduced the ability of zinc to activate pAkt and pErk. Zinc also activated several associated novel transcription factor pathways including Nrf1/Nrf2, ATF6, CREB, EGR1, STAT1, AP-1, PPAR, and TCF/LEF, and pCREB protein over 120 min of zinc treatment. These studies have shown that zinc’s activity extends beyond that of insulin signalling and plays a role in modulating novel transcription factor activated pathways. Further studies to determine the exact role of zinc in the activation of transcription factor pathways will provide novel insights into this metal ion actions

    Reactive direction control for a mobile robot: A locust-like control of escape direction emerges when a bilateral pair of model locust visual neurons are integrated

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    Locusts possess a bilateral pair of uniquely identifiable visual neurons that respond vigorously to the image of an approaching object. These neurons are called the lobula giant movement detectors (LGMDs). The locust LGMDs have been extensively studied and this has lead to the development of an LGMD model for use as an artificial collision detector in robotic applications. To date, robots have been equipped with only a single, central artificial LGMD sensor, and this triggers a non-directional stop or rotation when a potentially colliding object is detected. Clearly, for a robot to behave autonomously, it must react differently to stimuli approaching from different directions. In this study, we implement a bilateral pair of LGMD models in Khepera robots equipped with normal and panoramic cameras. We integrate the responses of these LGMD models using methodologies inspired by research on escape direction control in cockroaches. Using ‘randomised winner-take-all’ or ‘steering wheel’ algorithms for LGMD model integration, the khepera robots could escape an approaching threat in real time and with a similar distribution of escape directions as real locusts. We also found that by optimising these algorithms, we could use them to integrate the left and right DCMD responses of real jumping locusts offline and reproduce the actual escape directions that the locusts took in a particular trial. Our results significantly advance the development of an artificial collision detection and evasion system based on the locust LGMD by allowing it reactive control over robot behaviour. The success of this approach may also indicate some important areas to be pursued in future biological research

    A computational model of ureteral peristalsis and an investigation into ureteral reflux.

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    The aim of this study is to create a computational model of the human ureteral system that accurately replicates the peristaltic movement of the ureter for a variety of physiological and pathological functions. The objectives of this research are met using our in-house fluid-structural dynamics code (CgLes-Y code). A realistic peristaltic motion of the ureter is modelled using a novel piecewise linear force model. The urodynamic responses are investigated under two conditions of a healthy and a depressed contraction force. A ureteral pressure during the contraction shows a very good agreement with corresponding clinical data. The results also show a dependency of the wall shear stresses on the contraction velocity and it confirms the presence of a high shear stress at the proximal part of the ureter. Additionally, it is shown that an inefficient lumen contraction can increase the possibility of a continuous reflux during the propagation of peristalsis

    A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

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    In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios
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