A weighted mean velocity feedback strategy in intelligent two-route traffic systems

Information feedback strategies can influence the traffic efficiency of intelligent traffic systems greatly.Based on the more practical symmetrical two-route scenario with one entrance and one exit,an improved weighted mean velocity feedback strategy（WMVFS） is proposed,which is not sensitive to the precision of global position system（GPS） devices.The applicability of WMVFS to different weight factors,aggressive probabilities,densities of dynamic vehicles,and different two-route scenarios（symmetrical scenario and asymmetrical scenario with a speed limit bottleneck） is analyzed.Results show that WMVFS achieves the best performance compared with three other information feedback strategies when considering the traffic flux and stability.

Feasibility of the 2-point method to determine the load-velocity relationship variables during the countermovement jump exercise

Purpose:This study aimed to examine the reliability and validity of load-velocity(L-V)relationship variables obtained through the 2-point method using different load combinations and velocity variables.Methods:Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads(20 kg,40 kg,60 kg,and80 kg)and a heavy squat against a load linked to a mean velocity(MV)of 0.55 m/s(load_(0.55)).The L-V relationship variables(load-axis intercept(L_(0)),velocity-axis intercept(v_(0)),and area under the L-V relationship line(A_(line)))were obtained using 3 velocity variables(MV,mean propulsive velocity(MPV),and peak velocity)by the multiple-point method including(20-40-60-80-load_(0.55))and excluding(20-40-60-80)the heavy squat,as well as from their respective 2-point methods(20-load_(0.55)and 20-80).Results:The L-V relationship variables were obtained with an acceptable reliability(coefncient of variation(CV)≤7.30%;intra-class correlation coefficient>0.63).The reliability of L_(0)and v_(0)was comparable for both methods(CV_(ratio)(calculated as higher value/lower value):1.11-1.12),but the multiple-point method provided Al_(ine)with a greater reliability(CV_(ratio)=1.26).The use of a heavy squat provided the L-V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load(CV_(ratio):1.06-1.19).The peak velocity provided the load-velocity relationship variables with the greatest reliability(CV_(ratio):1.15-1.86)followed by the MV(CV_(ratio):1.07-1.18),and finally the MPV.The 2-point methods only revealed an acceptable validity for the MV and MPV(effect size≤0.19;Pearson s product-moment correlation coefficient≥0.96;Lin's concordance correlation coefficient≥0.94).Conclusion:The 2-point method obtained from a heavy squat load and MV or MPV is a quick,safe,and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L-V relationship.

Close Correlations Between Carotid Arterial Mean Blood Flow Velocity,Body Mass Index,and Temperature in Normal Individuals

Objective:Assessing carotid and radial pulses is an essential sphygmology method in traditional Chinese medicine(TCM).It is believed in TCM and by doctors that pulse force is markedly linked with the physiological state of a human,including body mass index(BMI)and temperature.However,comprehensive analysis elucidating these potential correlations remains undetermined.Therefore,this investigation aimed to assess the association of pulse strength with human metabolism.Materials and Methods:The mean blood flow velocity(MBFV)of the carotid artery and pulse force of 122 healthy adults included in this investigation were assessed using ultrasound and manual palpation.Their thermal texture map was also acquired.Results:No substantial variation was observed in the carotid arterial MBFV among normal individuals(P>0.05)regardless of body side and gender.However,young individuals had higher blood velocity than middle-aged individuals(P<0.05).Furthermore,it was identified that MBFV was negatively associated with BMI and torso temperature;however,it was positively linked with hand temperature.Conclusions:This investigation revealed that carotid arterial MBFV could indicate the physical state of humans,including BMI and temperature,and therefore,is valuable for elucidating the effect of TCM on yin–yang.The data validated some TCM beliefs and supported the implementation of sphygmology in TCM.

Experiment on the Effect of Sediment Concentration on Flow Structure

The paper studies on the sediment-laden flow by using MicroADV.Laboratory calibration has been conducted to determine the relationship between backscattered signal strength and sediment concentration. Based on the experimental data,the interactions between sediment and fluid in open channel flow are investi- gated.The experiment shows that there exist inner relation between sediment concentration and turbulence, and the relationship is distinctry related to the diameter of particle as well as the flow co...

Forest Canopy Flow Analysis Using Turbulence Model with Source/Sink Terms

A computational fluid dynamics( CFD) model was presented to simulate wind flow over a forest canopy for analyzing the wind flow within and above forest canopies. Unlike previous studies on the canopy flow,the effect of canopy contour on the canopy was considered to develop the simulation method into a more general but complex case of wind flow over a forest canopy,using cedrus deodara and cinnamomum camphora. The desire of this work is mainly motivated to provide a rational way for predicting the wind flow within and above vegetation canopies. The model of canopy is not incorporated in the geometrical model,and it uses a porous domain combined with k-ε two-equation turbulence model with source / sink terms. The objectives of this paper are to analyze the contour of pressure and velocity and compare the simulation results with other works and field measurements. Results are encouraging,as the model profiles of mean velocity( u) qualitatively agree well with other works compared with and quantitatively have similar explanations as several authors. In conclusion, it is demonstrated that the adoption turbulence model with source / sink terms for forest canopies is proved to be a physically accurate and numerically robust method. The model and method are recommended for future use in simulating turbulent flows in forest canopies.

Transverse radius dependence for transverse velocity and elliptic flow in intermediate energy HIC

The mean transverse velocity and elliptic flow of light fragments （A≤2） as a function of transverse radius are studied for 25 MeV/nucleon 64Cu＋64Cu collisions with impact parameters 3–5 fm by the isospin- dependent quantum molecular dynamics model. By comparison between the in-plane and the out-of-plane transverse velocities, the elliptic flow dependence on the transverse radius can be understood qualitatively, and variation of the direction of the resultant force on the fragments can be investigated qualitatively.

Slowing down critical transitions via Gaussian white noise and periodic force

Stochastic perturbations and periodic excitations are generally regarded as sources to induce critical transitions in complex systems. However, we find that they are also able to slow down an imminent critical transition. To illustrate this phenomenon, a periodically driven bistable eutrophication model with Gaussian white noise is introduced as a prototype class of real systems.The residence probability(RP) is presented to measure the possibility that the given system stays in the oligotrophic state versus Gaussian white noise and periodic force. Variations in the mean first passage time(MFPT) and the mean velocity(MV) of the first right-crossing process are also calculated respectively. We show that the frequency of the periodic force can increase the MFPT while reduce the MV under different control parameters. Nevertheless, the noise intensity or the amplitude may result in an increase of the RP only in the case of control parameters approaching the critical values. Furthermore, for an impending critical transition, an increase of the RP appears with the interaction between the amplitude and noise intensity or the combination of the noise intensity and frequency, while the interaction of the frequency and amplitude leads to an extension of the MFPT or a decrease of the MV. As a result, an increase of the RP and MFPT, and a decrease of the MVobtained from our results claim that it is possible to slow down an imminent critical transition via Gaussian white noise and periodic force.

Discrete particle simulation of mixed sand transport

An Eulerian/Lagrangian numerical simulation is performed on mixed sand transport. Volume averaged Navier-Stokes equations are solved to calculate gas motion, and particle motion is calculated using Newton＇s equation, involving a hard sphere model to describe particle-to-particle and particle-to-wall collisions. The influence of wall characteristics, size distribution of sand particles and boundary layer depth on vertical distribution of sand mass flux and particle mean horizontal velocity is analyzed, suggesting that all these three factors affect sand transport at different levels. In all cases, for small size groups, sand mass flux first increases with height and then decreases while for large size groups, it decreases exponen- tially with height and for middle size groups the behavior is in-between. The mean horizontal velocity for all size groups well fits experimental data, that is, increasing logarithmically with height in the middle height region. Wall characteristics greatly affects particle to wall collision and makes the fiat bed similar to a Gobi surface and the rough bed similar to a sandy surface. Particle size distribution largely affects the sand mass flux and the highest heights they can reach especially for larger particles.

Study on the flow structure around discontinued vertically layered vegetation in an open channel

The flow structure and geomorphology of rivers are significantly affected by vegetation patterns. In the present study, the effect of vegetation in the form of discontinuous and vertically double layered patches particularly on the resulting flow turbulence was examined computationally in an open channel. A k-ɛ model was implemented in this research work which was developed using 3-D numerical code FLUENT (ANSYS). After the validation process of numerical model, the impact of discontinuous layered vegetation patches on the flow turbulence was investigated against varying vegetation density and patch length. The mean stream-wise velocities at specified positions showed larger spatial fluctuations directly upstream and downstream of vegetation elements, whereas sharp inflections in the profiles were witnessed at the top of smaller submerged elements i.e. z/hs= 1 (where z is the flow depth and hs is the smaller vegetation height). The reduction in flow velocity due to tall vegetation structure was more as compared with that of short vegetation. The mean velocity in the patch regions was visibly higher than that in the gap regions. The profiles of turbulent flow properties showed more rise and fall within the patches with a high vegetation density i.e. Ss/d= 4;and St/d= 8 (where Ss/d and St/d are the smaller and taller vegetation spacing, while d is the vegetation diameter) as compared with low vegetation density i.e. Ss/d= 8;and St/d= 16. The turbulent flow structure in the large patch and gap regions was found to be more stable than that in the small patches and gaps;whereas, due to the variation in distribution form of the patch, turbulence is relatively unaffected, and the flow structure variation is low. Turbulence was observed to be large, followed by a saw-tooth distribution within the patches;whereas, low turbulence is observed in the non-vegetation regions. The turbulent intensity acquired maximum of 13% turbulence for dense vegetation arrangement as compared to that of sparse arrangement having maximum of 9% turbulent intensity. A noteworthy rise in turbulent kinetic energy and turbulent intensity was witnessed as the flow passed through the vegetated regions. Hence, a non-uniform flow was observed through discontinuous and double layered vegetation patches.