969 research outputs found
A Fokker-Planck Feedback Control-Constrained Approach for Modeling Crowd Motion
No full textA Fokker–Planck control approach to model crowd motion is investigated. This strategy is formulated as a bilinear optimal control-constrained problem governed by the Fokker–Planck equation modeling the evolution of the probability density function of the stochastic motion of the crowd. Theoretical results on existence and regularity of controls are provided. For computational purposes, the resulting optimality system is discretized using an alternate-direction implicit Chang–Cooper scheme that guarantees conservativeness, positivity, L2 stability, and second-order accuracy of the forward solution. A projected non-linear conjugate gradient scheme is used to solve the optimality system. Results of numerical experiments demonstrate the efficiency of the proposed control framework
A Fokker-Planck approach to control collective motion
No full textA Fokker-Planck control strategy for collective motion is investigated. This strategy is formulated as the minimisation of an expectation objective with a bilinear optimal control problem governed by the Fokker-Planck equation modelling the evolution of the probability density function of the stochastic motion. Theoretical results on existence and regularity of optimal controls are provided. The resulting optimality system is discretized using an alternate-direction implicit Chang-Cooper scheme that guarantees conservativeness, positivity, (Formula presented.) stability, and second-order accuracy of the forward solution. A projected non-linear conjugate gradient scheme is used to solve the optimality system. Results of numerical experiments validate the theoretical accuracy estimates and demonstrate the efficiency of the proposed control framework
Editorial: Light-Assisted Molecular and Hybrid Systems for Artificial Photosynthesis
No full textEditorial on the Research Topic Light-Assisted Molecular and Hybrid Systems for Artificial Photosynthesi
Performance Benefits of Fiber-Reinforced Thin Concrete Pavement and Overlays
No full textThis study investigates the performance benefits of synthetic structural fibers in mitigating distresses in thin concrete pavements and overlays. In this study, two ultra-thin (3 and 4 inches thick) and four thin (5 and 6 inches thick) concrete pavements placed on a gravel base along with two thin unbonded concrete overlay cells (5 inches thick) placed on an existing concrete pavement were constructed at the Minnesota Road Research (MnROAD) facility in 2017. This report discusses the objectives and methodology of the research, including the construction of the test cells, instrumentation, traffic load application, and data collection and analysis procedures. The structural responses and distresses observed over three years, such as fatigue cracking and faulting, as well as the joint performance measured in each cell, were discussed and compared in this report.The National Road Research Alliance (NRRA) is a pooled fund project administered by the Minnesota Department of Transportation.Barman, Manik; Roy, Souvik; Tiwari, Amarjeet; Burnham, Tom. (2021). Performance Benefits of Fiber-Reinforced Thin Concrete Pavement and Overlays. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/225059
Synthetic Macro-Fibers for Mitigating Distresses in Thin Concrete Pavements
No full textUniversity of Minnesota M.S. thesis. July 2021. Major: Civil Engineering. Advisor: Manik Barman. 1 computer file (PDF); vii, 94 pages.Application of Fiber Reinforced Concrete (FRC) in constructing concrete pavement overlaysand new concrete pavements is gaining more attention. However, there has been limited
research on quantifying the performance benefits of fiber and its dosage in concrete
pavements, specifically in thin concrete pavements. The present study focused on determining
the influence of synthetic macro-fibers in keeping the joint performance high for a longer
duration of pavement service life and in mitigating thin concrete pavement distresses such as
transverse joint faulting and fatigue cracking. Field data was collected from fiber reinforced
in-service test sections at the MnROAD test facility, located on I-94 westbound, 35 miles
north-west of the twin cities metropolitan area, Minnesota. Field data included, falling weight
deflectometer (FWD), environmental strain, transverse joint faulting, international roughness
index (IRI), and crack survey data. It was found that joint performance was significantly
affected by the inclusion of fibers. High fiber dosage resulted in greater LTE, lower
differential displacement, and lower loaded-side displacement. A faulting prediction equation
was proposed on the basis of faulting data and statistical relationships. A relationship was also
established between the joint faulting and IRI. The distress data analysis indicated that fatigue
cracking may not be the dominant distress of the thin fiber reinforced pavements, but the
transverse joint faulting is.Roy, Souvik. (2021). Synthetic Macro-Fibers for Mitigating Distresses in Thin Concrete Pavements. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/224502
Review: Videogames in the Indian Subcontinent: Development, Culture(s) and Representations
No full textReview: Videogames in the Indian Subcontinent: Development, Culture(s) and Representations, by Souvik Mukherjee. 2022. Bloomsbury. 256 pp
Review: Videogames in the Indian Subcontinent: Development, Culture(s) and Representations
No full textReview: Videogames in the Indian Subcontinent: Development, Culture(s) and Representations, by Souvik Mukherjee. 2022. Bloomsbury. 256 pp
Catalytic Hydrogen Evolution by Fe(II) Carbonyls Featuring a Dithiolate and a Chelating Phosphine
No full textabstract: Two pentacoordinate mononuclear iron carbonyls of the form (bdt)Fe(CO)P[subscript 2] [bdt = benzene-1,2-dithiolate; P[subscript 2] = 1,1′-diphenylphosphinoferrocene (1) or methyl-2-{bis(diphenylphosphinomethyl)amino}acetate (2)] were prepared as functional, biomimetic models for the distal iron (Fe[subscript d]) of the active site of [FeFe]-hydrogenase. X-ray crystal structures of the complexes reveal that, despite similar ν(CO) stretching band frequencies, the two complexes have different coordination geometries. In X-ray crystal structures, the iron center of 1 is in a distorted trigonal bipyramidal arrangement, and that of 2 is in a distorted square pyramidal geometry. Electrochemical investigation shows that both complexes catalyze electrochemical proton reduction from acetic acid at mild overpotential, 0.17 and 0.38 V for 1 and 2, respectively. Although coordinatively unsaturated, the complexes display only weak, reversible binding affinity toward CO (1 bar). However, ligand centered protonation by the strong acid, HBF[subscript 4]·OEt[subscript 2], triggers quantitative CO uptake by 1 to form a dicarbonyl analogue [1(H)-CO][superscript +] that can be reversibly converted back to 1 by deprotonation using NEt[subscript 3]. Both crystallographically determined distances within the bdt ligand and density functional theory calculations suggest that the iron centers in both 1 and 2 are partially reduced at the expense of partial oxidation of the bdt ligand. Ligand protonation interrupts this extensive electronic delocalization between the Fe and bdt making 1(H)[superscript +] susceptible to external CO binding
Oxytate kanishkai
No full textOxytate kanishkai (Gajbe, 2008) Dieta kanishkai Gajbe, 2008: 59, figs 1–3 (description and illustrations of female). Type material. Holotype female from INDIA: Madhya Pradesh: Jabalpur, Tilwaraghat, 02 September 2006, leg. U.A. Gajbe, not examined. Remarks. O. kanishkai was described based on a single female specimen collected from Jabalpur, Madhya Pradesh, and was neither recollected nor re-described after its original description. We were unable to trace the type specimen in the National Zoological Collection of ZSI, even though the author mentioned that the type would be deposited there. We inquired about the availability of the type at the Zoological Survey of India, Central Zone Regional Centre, Jabalpur, Madhya Pradesh because the author was working there at that time. Unfortunately, we couldn’t find the type specimen from there as well. Therefore, the type material of O. kanishkai is currently considered lost. The female copulatory organ of this species is quite distinct from other Oxytate species reported in India. Although the illustrations are poor, the laterally oriented spermathecae, and the lack of anterior hood cannot be seen in any other Indian congeners (cf. Figs 1C, G–H, 2C–D, G–H, 4 D–F, 5A–E, and 6C–D with figs 2–3 in Gajbe 2008). The available description and the illustrations might help in the identifications of freshly collected specimens from the type locality (Gajbe 2008: figs 1–3). Therefore, we refrain to suggest this name as a nomen dubium.Published as part of Sudhin, Puthoor Pattammal & Sen, Souvik, 2023, Taxonomic notes on the crab spider genus Oxytate L. Koch, 1878 (Araneae: Thomisidae) from India, pp. 549-558 in Zootaxa 5315 (6) on page 553, DOI: 10.11646/zootaxa.5315.6.2, http://zenodo.org/record/814246
Restructuring Wireless Systems using PHY Layer Information
No full textWireless and mobile systems play an increasingly important role in our lives. Fueled by an array of innovative services and applications, mobile data traffic is surging rapidly. Traditionally, wireless traffic growth is met by acquiring new spectrum. However, wireless spectrum demand is soon going to surpass it's availability. Thus, there is an urgent need for major innovations in wireless network architecture, so that our spectrum utilization can achieve its full potential. Motivated by this problem, we explore an alternative design of physical layer aware wireless systems.Typical approaches towards improving wireless performance is confined within the physical (PHY) or link layers of the networking stack, providing only partial so- lutions. In this thesis, we advocate to consider the entire network architecture holis- tically. We show how rich PHY layer information can be utilized to address existing challenges in wireless networking - contention resolution, rate control, interference management, etc. We design, implement, and experimentally evaluate protocols to understand network-wide implications of PHY-aware systems. We also pursue the observation that PHY layer not only encode bits but also contain rich information about the ambience, and hence can be viewed as a sensor. This sensing informa- tion can be further coupled with other phone sensors, thereby benefitting pervasive mobile services and applications. We demonstrate how this synergy can contribute towards designing precise indoor localization systems, an important building block for next generation mobile applications.</p
- …
