278 research outputs found
Optimal energy management for a flywheel-based hybrid vehicle
This paper presents the modeling and design of an optimal Energy Management Strategy (EMS) for a flywheel-based hybrid vehicle, that does not use any electrical motor/generator, or a battery, for its hybrid functionalities. The hybrid drive train consists of only low-cost components, such as a flywheel module and a continuously variable transmission. This hybrid drive train is characterized by a relatively small energy capacity (flywheel) and discrete shifts between operation modes, due to the use of clutches. The main design criterion of the optimized EMS is the minimization of the overall fuel consumption, over a pre-defined driving cycle. In addition, comfort criteria are formulated as constraints, e.g., to avoid high-frequent shifting between driving modes. The criteria are used to find the optimal sequence of driving modes and the generated engine torque. Simulations show a fuel saving potential of 20% to 39%, dependent on the chosen driving cycle
Kinetics of Eotaxin Generation and Its Relationship to Eosinophil Accumulation in Allergic Airways Disease: Analysis in a Guinea Pig Model In Vivo
Challenge of the airways of sensitized guinea pigs with aerosolized ovalbumin resulted in an early phase of microvascular protein leakage and a delayed phase of eosinophil accumulation in the airway lumen, as measured using bronchoalveolar lavage (BAL). Immunoreactive eotaxin levels rose in airway tissue and BAL fluid to a peak at 6 h falling to low levels by 12 h. Eosinophil numbers in the tissue correlated with eotaxin levels until 6 h but eosinophils persisted until the last measurement time point at 24 h. In contrast, few eosinophils appeared in BAL over the first 12 h, major trafficking through the airway epithelium occurring at 12–24 h when eotaxin levels were low. Constitutive eotaxin was present in BAL fluid. Both constitutive and allergen-induced eosinophil chemoattractant activity in BAL fluid was neutralized by an antibody to eotaxin. Allergen-induced eotaxin appeared to be mainly in airway epithelium and macrophages, as detected by immunostaining. Allergen challenge of the lung resulted in a rapid release of bone marrow eosinophils into the blood. An antibody to IL-5 suppressed bone marrow eosinophil release and lung eosinophilia, without affecting lung eotaxin levels. Thus, IL-5 and eotaxin appear to cooperate in mediating a rapid transfer of eosinophils from the bone marrow to the lung in response to allergen challenge
Binary Willshaw learning yields high synaptic capacity for long-term familiarity memory
We investigate from a computational perspective the efficiency of the
Willshaw synaptic update rule in the context of familiarity discrimination, a
binary-answer, memory-related task that has been linked through psychophysical
experiments with modified neural activity patterns in the prefrontal and
perirhinal cortex regions. Our motivation for recovering this well-known
learning prescription is two-fold: first, the switch-like nature of the induced
synaptic bonds, as there is evidence that biological synaptic transitions might
occur in a discrete stepwise fashion. Second, the possibility that in the
mammalian brain, unused, silent synapses might be pruned in the long-term.
Besides the usual pattern and network capacities, we calculate the synaptic
capacity of the model, a recently proposed measure where only the functional
subset of synapses is taken into account. We find that in terms of network
capacity, Willshaw learning is strongly affected by the pattern coding rates,
which have to be kept fixed and very low at any time to achieve a non-zero
capacity in the large network limit. The information carried per functional
synapse, however, diverges and is comparable to that of the pattern association
case, even for more realistic moderately low activity levels that are a
function of network size.Comment: 20 pages, 4 figure
Kinetics of Eotaxin Generation and Its Relationship to Eosinophil Accumulation in Allergic Airways Disease: Analysis in a Guinea Pig Model In Vivo
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