The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Kemal S Turker - One of the best experts on this subject based on the ideXlab platform.
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estimates of epsp amplitude based on changes in motoneuron Discharge Rate and probability
Experimental Brain Research, 2010Co-Authors: Randall K Powers, Kemal S TurkerAbstract:When motor units are discharging tonically, transient excitatory synaptic inputs produce an increase in the probability of spike occurrence and also increase the instantaneous Discharge Rate. Several researchers have proposed that these induced changes in Discharge Rate and probability can be used to estimate the amplitude of the underlying excitatory post-synaptic potential (EPSP). We tested two different methods of estimating EPSP amplitude by comparing the amplitude of simulated EPSPs with their effects on the Discharge of rat hypoglossal motoneurons recorded in an in vitro brainstem slice preparation. The first estimation method (simplified-trajectory method) is based on the assumptions that the membrane potential trajectory between spikes can be approximated by a 10 mV post-spike hyperpolarization followed by a linear rise to the next spike and that EPSPs sum linearly with this trajectory. We hypothesized that this estimation method would not be accuRate due to interspike variations in membrane conductance and firing threshold that are not included in the model and that an alternative method based on estimating the effective distance to threshold would provide more accuRate estimates of EPSP amplitude. This second method (distance-to-threshold method) uses interspike interval statistics to estimate the effective distance to threshold throughout the interspike interval and incorpoRates this distance-to-threshold trajectory into a threshold-crossing model. We found that the first method systematically overestimated the amplitude of small ( 5 mV EPSPs). For large EPSPs, the degree of underestimation increased with increasing background Discharge Rate. Estimates based on the second method were more accuRate for small EPSPs than those based on the first model, but estimation errors were still large for large EPSPs. These errors were likely due to two factors: (1) the distance to threshold can only be directly estimated over a limited portion of the interspike interval and (2) the distance to threshold can be affected by the EPSP itself. Both methods provide the most accuRate EPSP estimates for EPSP amplitudes less than 5 mV and modeRate background Discharge Rates (~15 imp/s).
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EMG, force and Discharge Rate analysis of human jaw reflexes in response to axial stimulation of the incisor
Experimental Brain Research, 2005Co-Authors: Russell S. A. Brinkworth, Kemal S TurkerAbstract:Reflex studies utilising controlled stimulation along the long axis of human incisors are relatively new, and the effects that various stimulus parameters have on the elicited reflexes are not fully understood. Twelve subjects were recruited to determine the effects that contraction level, stimulus force and amount of constant force applied between stimuli have on the reflex response of the masseter muscle. Multi-unit intramuscular electromyogram (EMG) was recorded alongside surface EMG to determine whether any differences existed between the two. Furthermore, cumulative peri-stimulus “Dischargegrams” were constructed to determine whether events seen in the EMG corresponded to changes in the Discharge Rates of the underlying motor units. Axial stimulation of the incisor induced a response in the EMG comprising of peak–trough–peak, with the trough being the most dominant. The bite force record showed only a reduction (relaxation) in response to the stimulation. The most significant experimental factor affecting the reflex occurrence and strength was the stimulus force. Although the latency, duration and occurrence Rates were not significantly different, the strength of the responses was greater in intramuscular recordings compared with the surface recordings. Discharge Rate analysis showed that approximately two-thirds of the late peaks detected in the EMG did not correspond to an increase in the Discharge Rates of the underlying units; hence they were due to the clustering of action potentials following the trough and not to a change in the membrane potential of the motoneurone. It was also found that the duration of the trough, as seen by the reduced cumulative Discharge Rate of the underlying units, was longer than indicated by the EMG.
Serge P. Hoogendoorn - One of the best experts on this subject based on the ideXlab platform.
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Capacity drop: A relation between the speed in congestion and the queue Discharge Rate
2020Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:It has been empirically observed for years that the queue Discharge Rate is lower than the pre-queue capacity. This is called the capacity drop. The magnitude of capacity drop varies over a wide range depending on the local traffic conditions. However, up to now it is unknown what determines the capacity drop value. In fact, there is still no thorough empirical analysis revealing a reliable relation between the congestion level and the capacity drop. This paper tries to fill in the gap by revealing the relation between the vehicle speed in congestion and the queue Discharge Rate through empirical analysis. The queue Discharge Rate is shown to increase considerably with increasing speed in the congestion. This finding indicates a promising speed-control scheme for increasing queue Discharge Rates.
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Capacity Drop: Relationship Between Speed in Congestion and the Queue Discharge Rate
Transportation Research Record, 2019Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:It has been empirically observed for years that the queue Discharge Rate is lower than the prequeue capacity. This difference is called the capacity drop. The magnitude of capacity drop varies over...
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A Microscopic Investigation Into the Capacity Drop: Impacts of Longitudinal Behavior on the Queue Discharge Rate
Transportation Science, 2017Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:The capacity drop indicates that the queue Discharge Rate is lower than the free-flow capacity. Studies show that the queue Discharge Rate varies under different traffic conditions. Empirical data show that the queue Discharge Rate increases as the speed in congestion increases. Insights into the underlying behavioral mechanisms that cause these variable queue Discharge Rates can help minimize traffic delays and eliminate congestion. However, to our knowledge, few efforts have been devoted to testing impacts of traffic behaviors on the queue Discharge Rate. This paper tries to fill this gap. We investigate to what extent the acceleration spread and reaction time can influence the queue Discharge Rate. It is found that the (interdriver) acceleration spread does not reduce the queue Discharge Rates as much as found empirically. Modeling reaction time might be more important than modeling acceleration for capacity drop in car-following models. A speed-dependent reaction time mechanism for giving variable que...
Yang Shaohorn - One of the best experts on this subject based on the ideXlab platform.
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the Discharge Rate capability of rechargeable li o2 batteries
Energy and Environmental Science, 2011Co-Authors: Yichun Lu, David G Kwabi, Jonathon R Harding, Jigang Zhou, Lucia Zuin, Yang ShaohornAbstract:The O2electrode in Li–O2cells was shown to exhibit gravimetric energy densities (considering the total weight of oxygen electrode in the Discharged state) four times that of LiCoO2 with comparable gravimetric power. The Discharge Rate capability of Au-catalyzed Vulcan carbon and pure Vulcan carbon (VC) as the O2electrode was studied in the range of 100 to 2000 mA gcarbon−1. The Discharge voltage and capacity of the Li−O2 cells were shown to decrease with increasing Rates. Unlike propylene carbonate based electrolytes, the Rate capability of Li−O2 cells tested with 1,2-dimethoxyethane was found not to be limited by oxygen transport in the electrolyte. X-Ray diffraction (XRD) showed lithium peroxide as the Discharge product and no evidence of Li2CO3 and LiOH was found. It is hypothesized that higher Discharge voltages of cells with Au/C than VC at low Rates could have originated from higher oxygen reduction activity of Au/C. At high Rates, higher Discharge voltages with Au/C than VC could be attributed to faster lithium transport in nonstoichiometric and defective lithium peroxide formed upon Discharge, which is supported by XRD and X-ray absorption near edge structure O and Li K edge data.
Prakash Ranjitkar - One of the best experts on this subject based on the ideXlab platform.
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Traffic Signal Design with an Increasing Queue Discharge Rate
Asian transport studies, 2020Co-Authors: Mohsin Shahzad Chaudhry, Prakash RanjitkarAbstract:The traditional method of traffic signal design is based on the assumption of a constant queue Discharge Rate, also termed the saturation flow Rate. However, a number of field studies conducted in Taiwan and the USA contradict this assumption because they reported a marginally increasing trend observed for the queue Discharge Rate toward the back of the queue. This paper reports on a field study conducted in Auckland, New Zealand at six signalized intersections. The field observations confirm the findings of previous research, namely that the queue Discharge Rate increases toward the back of the queue. Two empirical models are proposed to reflect the observed queue Discharge behavior. One of them is implemented to calculate the capacity and signal timings. The proposed model shows the potential to overcome the shortcomings of the traditional method in practical applications.
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Delay Estimation at Signalized Intersections with Variable Queue Discharge Rate
Journal of the Eastern Asia Society for Transportation Studies, 2020Co-Authors: Mohsin Sahzad Chaudhry, Prakash RanjitkarAbstract:The techniques developed for delay estimation in most traffic signal design guidelines are based on the assumption that queue Discharge Rate at signalized intersections becomes stable after a few vehicles pass through the stop line, which is termed as saturation flow Rate. This assumption has been challenged in recent times as a number of field observations in different parts of the world reported an increasing queue Discharge Rate observed along the back of the queue. This paper proposes an empirical model that is capable of capturing the queue Discharge behavior observed at signalized intersections. The model is implemented to estimate delay and compared with the existing delay models. The results revealed that the proposed model can overcome the deficiencies of the existing models and can estimate delay more accuRately.
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Estimation of Delay at Signalized Intersections with an Increasing Discharge Rate
2020Co-Authors: Mohsin Shahzad Chaudhry, Prakash RanjitkarAbstract:Delay is an important measure widely used traffic engineering to measure the operational efficiency of traffic control systems as well as to optimize them. A reasonable number of literatures have claimed an increasing Discharge Rate observed at signalized intersections. These results contradict with a widely accepted traditional concept of a constant saturation flow Rate adopted in the most commonly used traffic signal design guidelines such as highway capacity manual (HCM) (2010) and ARR 123 by Akcelik (1981). This paper proposes an empirical model incorporating an increasing queue Discharge Rate based on what observed in the field data collected from Auckland, New Zealand. The model is implemented to estimate delay at signalized intersections and then compared with the existing methods of delay estimation. The results revealed some prospects for this model to improve delay estimation at signalized intersections.
Kai Yuan - One of the best experts on this subject based on the ideXlab platform.
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Capacity drop: A relation between the speed in congestion and the queue Discharge Rate
2020Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:It has been empirically observed for years that the queue Discharge Rate is lower than the pre-queue capacity. This is called the capacity drop. The magnitude of capacity drop varies over a wide range depending on the local traffic conditions. However, up to now it is unknown what determines the capacity drop value. In fact, there is still no thorough empirical analysis revealing a reliable relation between the congestion level and the capacity drop. This paper tries to fill in the gap by revealing the relation between the vehicle speed in congestion and the queue Discharge Rate through empirical analysis. The queue Discharge Rate is shown to increase considerably with increasing speed in the congestion. This finding indicates a promising speed-control scheme for increasing queue Discharge Rates.
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Capacity Drop: Relationship Between Speed in Congestion and the Queue Discharge Rate
Transportation Research Record, 2019Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:It has been empirically observed for years that the queue Discharge Rate is lower than the prequeue capacity. This difference is called the capacity drop. The magnitude of capacity drop varies over...
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A Microscopic Investigation Into the Capacity Drop: Impacts of Longitudinal Behavior on the Queue Discharge Rate
Transportation Science, 2017Co-Authors: Kai Yuan, Victor L. Knoop, Serge P. HoogendoornAbstract:The capacity drop indicates that the queue Discharge Rate is lower than the free-flow capacity. Studies show that the queue Discharge Rate varies under different traffic conditions. Empirical data show that the queue Discharge Rate increases as the speed in congestion increases. Insights into the underlying behavioral mechanisms that cause these variable queue Discharge Rates can help minimize traffic delays and eliminate congestion. However, to our knowledge, few efforts have been devoted to testing impacts of traffic behaviors on the queue Discharge Rate. This paper tries to fill this gap. We investigate to what extent the acceleration spread and reaction time can influence the queue Discharge Rate. It is found that the (interdriver) acceleration spread does not reduce the queue Discharge Rates as much as found empirically. Modeling reaction time might be more important than modeling acceleration for capacity drop in car-following models. A speed-dependent reaction time mechanism for giving variable que...