Stochastic Multi-class Traffic Assignment for Autonomous and Regular Vehicles in a Transportation Network

A transition period from regular vehicles (RVs) to autonomous vehicles (AVs) is imperative. This article explores both types of vehicles using a route choice model, formulated as a stochastic multi-class traffic assignment (SMTA) problem. In RVs, cross-nested logit (CNL) models are used since drivers do not have complete information and the unique characteristics of CNL. AVs, however, are considered to behave in a user equilibrium (UE) due to complete information about the network. The main innovation of this article includes the introduction of three solution methods for SMTA. Depending on the size of the network, each method can be used. These methods include solving the nonlinear complementary problem (NCP) with GAMS software, the decomposition-assignment algorithm, and the modified Wang's algorithm. Through the modification of Wang's algorithm, we have increased the convergence speed of Wang's algorithm and shown its numerical results for the Nguyen and Sioux Falls networks. As it is not possible to consider all paths in the traffic assignment, we proposed a creative path generation-assignment (PGA) algorithm. This algorithm generates several attractive paths for each origin-destination (OD), and the modified Wang's algorithm assigns traffic flow. Keywords: Autonomous Vehicles, Stochastic Multi-class Traffic Assignment, Cross-Nested Logit Mode

Breathing as a Fundamental Rhythm of Brain Function

Ongoing fluctuations of neuronal activity have long been considered intrinsic noise that introduces unavoidable and unwanted variability into neuronal processing, which the brain eliminates by averaging across population activity (Georgopoulos et al., 1986; Lee et al., 1988; Shadlen and Newsome, 1994; Maynard et al., 1999). It is now understood, that the seemingly random fluctuations of cortical activity form highly structured patterns, including oscillations at various frequencies, that modulate evoked neuronal responses (Arieli et al., 1996; Poulet and Petersen, 2008; He, 2013) and affect sensory perception (Linkenkaer-Hansen et al., 2004; Boly et al., 2007; Sadaghiani et al., 2009; Vinnik et al., 2012; Palva et al., 2013). Ongoing cortical activity is driven by proprioceptive and interoceptive inputs. In addition, it is partially intrinsically generated in which case it may be related to mental processes (Fox and Raichle, 2007; Deco et al., 2011). Here we argue that respiration, via multiple sensory pathways, contributes a rhythmic component to the ongoing cortical activity. We suggest that this rhythmic activity modulates the temporal organization of cortical neurodynamics, thereby linking higher cortical functions to the process of breathing

Effect of deep brain stimulation on vocal motor control mechanisms in Parkinson's disease

Published online: March 07, 2019motor symptoms in Parkinson's disease (PD); however, its effect on vocal motor function has yielded conflicted and highly variable results. The present study investigated the effects of STN-DBS on the mechanisms of vocal production and motor control. Methods: A total of 10 PD subjects with bilateral STN-DBS implantation were tested with DBS ON and OFF while they performed steady vowel vocalizations and received randomized upward or downward pitch-shift stimuli (±100 cents) in their voice auditory feedback. Results: Data showed that the magnitude of vocal compensation responses to pitch-shift stimuli was significantly attenuated during DBS ON vs. OFF (p = 0.012). This effect was direction-specific and was only observed when subjects raised their voice fundamental frequency (F0) in the opposite direction to downward stimuli (p = 0.019). In addition, we found that voice F0 perturbation (i.e. jitter) was significantly reduced during DBS ON vs. OFF (p = 0.022), and this DBS-induced modulation was positively correlated with the attenuation of vocal compensation responses to downward pitch-shift stimuli (r = +0.57, p = 0.028). Conclusions: These findings provide the first data supporting the role of STN in vocal F0 motor control in response to altered auditory feedback. The DBS-induced attenuation of vocal compensation responses may result from increased inhibitory effects of the subcortical hyperdirect (fronto-subthalamic) pathways on the vocal motor cortex, which can help stabilize voice F0 and ameliorate vocal motor symptoms by impeding PD subjects’ abnormal (i.e. overshooting) vocal responses to alterations in the auditory feedback

HAVOK Model Predictive Control for Time-Delay Systems with Applications to District Heating

A computationally efficient Model-Predictive Control (MPC) approach is proposed for systems with unknown delay using only input/output data. We use the Koopman operator framework and the related Hankel Alternative View of Koopman (HAVOK) algorithm to identify a model in a basis of projected time-delay coordinates and demonstrate a novel MPC structure that reduces and bounds the computational complexity. The proposed HAVOK-MPC approach is validated experimentally on a laboratory-scale District Heating System (DHS), demonstrating excellent prediction and tracking performance while only requiring knowledge of a conservative upper bound on the system delay.Comment: This work has been accepted for publication at IFAC World Congress 202

Evaluation of the Fouling Phenomenon During Membrane Clarification of Apple Juice Using Scraped Surface Membrane Unit

Introduction As a useful fruit for humans, apple (Malus domestica) is a good sourceof antioxidants, minerals, ascorbic acid, vitamins, polyphenols, fibers and other essential elements with medicinal properties. Improving the storage time of apple juice and maintaining the stability of extracts with high Brix value (during transportation and storage) and its marketability by removing the remaining water as well as reducing the turbidity, viscosity and brown color caused by colloidal suspended solids. Large (pectin, protopectin, pigments, polymeric carbohydrates, tannin, starch, cellulose, hemicellulose, fibers, etc.) is of great importance. Due to the presence of colloidal suspended solid particles and compounds that settle over time (mold, bacteria, plant cell fragments, pectin-tannin complex), apple juice must be clarified before concentration. Due to the high-energy consumption, time-consuming, degradation of thermo-sensitive components, and reduction of nutritional value in traditional methods, recently, the use of membrane concentration in food and beverage production holds great potential.. Despite all the benefits of membrane processes, one of the critical problems is permeate flux decline due to the concentration polarization and membrane fouling. In this study, an innovative mechanical motion was developed to remove the cake deposits on the membrane surface towards mitigating adverse effects of polarization and fouling.   Materials and Methods Membrane scraped surface module was designed and made with polyethylene material. The membrane was enclosed between the lower and upper parts of the module. These two parts are connected with screws and create a cylindrical part. Also, two caps are pressed axially to this cylindrical part by a metal frame to eliminate any unwanted leakage. The rotor shaft was coupled with an electric motor and the rotation of the output shaft was regulated by an inverter. A pump transferred the fresh fruit juice to the module through the inlet port and then it was divided into two output streams, permeate and retentate. The permeate was collected from the bottom of the module for further investigation and the retentate was returned to the juice tank. A polyethersulfone (PES) membrane with molecular weight cut-off (MWCO) of 4 kDa was used to clarify apple juice. Effects of the blade rotation speed (0, 600, 1400 and 2200 rpm), transmembrane pressure (TMP) (0.5, 1 and 1.5 bar), feed flow rate (FFR) (10, 15 and 20 ml/s) and the distance of the blade from the membrane surface (2 and 5 mm) on volumetric concentration factor (VCF) and fouling phenomenon were evaluated. Hermia model was used to study the main fouling mechanism and it was verified by scanning electron microscopy (SEM) images.   Results and Discussion  Results showed that rotating the blade with speed of 600 rpm at TMP of 0.5 bar, FFR of 10 ml/s and 2 mm distance from the membrane surface had the best performance in VCF and reducing fouling. The main mechanism of fouling was cake formation. Rotation of the blade decreases the intensity of cake formation and its thickness on the membrane surface and enhances the standard pore blocking. Also increasing the blade rotation speed changes the main fouling mechanism to the standard pore blocking due to the cake disintegration on the membrane surface and the penetration of fine particles into the membrane pores. As a result, the rotation of blade had a significant positive effect on increasing the VCF. On the other hand, the total resistance decreased with the rotation of the blade and by increasing the distance of blade from the membrane surface, the intensity of cake formation reduced. Also, the SEM images showed that in without blade rotation mode, the accumulation of cake particles on the membrane surface is thicker and denser than in with blade rotation mode. On the other hand, the low thickness of the cake layer formed on the membrane surface in the process of blade rotation is due to the turbulences resulting from the rotating blade. These observations confirm the results of the Hermia model in the previous sections.   Conclusion  In conclusion, the TMP 0.5 bar, FFR of 10 ml/s, blade rotation speed of 600 rpm with a distance of 2 mm from membrane surface were considered as the best conditions for ultrafiltration of apple juice using scraped-surface membrane unit

Do people who load their feet differently need insoles that have different stiffness?

Background: Plantar pressure reduction is an important aspect of diabetic foot management. However little information exists about the optimum cushioning properties of materials used in diabetic footwear as insoles/foot-beds. Numerical analyses have indicated that optimizing the material properties of footwear materials can improve their ability to reduce pressure. Aim: To investigate if the optimal insole stiffness would vary based on patients’ body mass (BM) in people with diabetic neuropathy. Method: Custom PU foams were produced using different ratios of chemical components to achieve a range of different stiffness. Uniform thickness (400 mm × 400 mm × 10 mm) foam sheets were produced with shore-A hardness between 3 and 45 and average(±stdev) increments of 5(±3). Standardized compression tests were performed for all 10 custom materials as well as for 3 commercially available foam materials used in diabetic footwear. Plantar pressure was measured during balanced standing on all custom material sheets for 4 diabetic neuropathic volunteers: 2 with BM of 49 kg ± 1 kg and 2 with BM of 73 kg ± 2 kg. Results: The maximum compressive force for 50% compression of the commercially available foams was similar to custom foams with 11–28 shore-A hardness. Peak plantar pressure was minimised for materials with shore-A hardness 6 and 11 in subjects with BM of 49 kg ± 1 kg and 73 kg ± 2 kg respectively. In all cases using softer or stiffer material (by 1 shore hardness increment) increased pressure by 24% ± 26% and 32% ± 34% respectively. Conclusions: Careful selection of insole/foot-bed stiffness can improve the pressure reduction capacity of diabetic footwear. Optimum material stiffness increased with the BM of the volunteers

Highly catalytically active CeO2-x-based heterojunction nanostructures with mixed micro/meso-porous architectures

Achieving high densities of accessible active sites in catalysts, which depend principally on the architecture of nanostructures, is critical to obtain enhanced performance. The present work introduces a template-free, high-yield, and flexible approach to fabricate 3D, mesoporous, CeO2-x nanostructures in centimeter-scale that are comprised of extremely thin holey 2D nanosheets. The method involves conversion of a stacked, 2D, Ce-based coordination polymer by controlling the removal kinetics of organic species. The resultant polycrystalline 2D-3D CeO2-x exhibits a large density of defects as well as outstanding surface areas of 251 m2 g-1. This mesoporous nanomaterial yields superior CO conversion performance (T90% = 148°C). Further improvements in catalysis were attained by synthesis CeO2-x -based transition metal oxides (TMOs) hetero-nanostructures, for which structural analyses and first principles simulations revealed active sites associated with the TMOs. This versatile fabrication technique delivers new pathways to engineer nanostructures and advance their functionalities for catalysis.Peer ReviewedPostprint (author's final draft