Modern control concepts in hydrology

Two approaches to an identification problem in hydrology are presented based upon concepts from modern control and estimation theory. The first approach treats the identification of unknown parameters in a hydrologic system subject to noisy inputs as an adaptive linear stochastic control problem; the second approach alters the model equation to account for the random part in the inputs, and then uses a nonlinear estimation scheme to estimate the unknown parameters. Both approaches use state-space concepts. The identification schemes are sequential and adaptive and can handle either time invariant or time dependent parameters. They are used to identify parameters in the Prasad model of rainfall-runoff. The results obtained are encouraging and conform with results from two previous studies; the first using numerical integration of the model equation along with a trial-and-error procedure, and the second, by using a quasi-linearization technique. The proposed approaches offer a systematic way of analyzing the rainfall-runoff process when the input data are imbedded in noise

Up-Down Unification, Neutrino Masses and Rare Lepton Decays

In a recent paper, we showed that tree level up-down unification of fermion Yukawa couplings is a natural consequence of a large class of supersymmetric models. They can lead to viable quark masses and mixings for moderately large values of $\tan\beta$ with interesting and testable predictions for CP violation in the hadronic sector. In this letter, we extend our discussion to the leptonic sector focusing on one particular class of these models, the supersymmetric left-right model with the seesaw mechanism for neutrino masses. We show that fitting the solar and the atmospheric neutrino data considerably restricts the Majorana-Yukawa couplings of the leptons in this model and leads to predictions for the decay $\tau\to \mu +\gamma$, which is found to be accessible to the next generation of rare decay searches. We also show that the resulting parameter space of the model is consistent with the requirements of generating adequate baryon asymmetry through lepton-number violating decays of the right-handed neutrino.Comment: 16 pages, latex, 6 figures, typos correcte

Simulation of Leksell Gamma Knife-4C System with Different Phantoms Using PHITS and Geant4

This study used PHITS and Geant4 code packages to simulate a Leksell Gamma Knife system in order to determine radiation dose distribution in two types of phantoms. The results observed in the water phantom with configurations of single source and 201 sources are in good accord with the prior research, including both simulation and experiment. Several characteristics of Leksell Gamma Knife 4C, such as dose profiles, output factor, FWHM, and penumbra size, are calculated based on Monte Carlo simulations, which show the best consistency with other results. The output factors for collimators of 14 mm, 8 mm, and 4 mm are 0.984, 0.949, and 0.872, respectively. The simulation results with an adult mesh-type reference phantom reveal considerable similarities with the established radiosurgery plans. It indicates that the absorbed dose in brain tumors was highest when utilizing the 18 mm collimator and subsequently reduced with collimator size to 0.65, 0.25, and 0.5 with the 14 mm, 8 mm, and 4 mm collimators, respectively. The absorbed dose has a very low value for other essential organs and decreases with distance from the brain tumor. These findings may explain why the dose to organs decreases linearly as target distance, volume, and collimator size increase

Modeling and parameter estimation in a PO3G Polyether process with time delay

A new model is developed to describe batch polycondensation of bio-based 1,3-propanediol (PO3G) to produce a polyether commercialized by DuPont as Cerenol® (see Figure 1). Cerenol® is valued for its biodegradability and low toxicity, as well as high end-group reactivity, low viscosity, low melting point and superior oxidative stability[1]. The proposed model provides an improved fit to the available data compared to the previous model of Cui et al. [2] The main reason for this improvement is that the revised model equations and parameter estimation methodologies that were used account for time delay and accumulation of evaporated water, monomer and linear oligomers in the overhead condenser system. To handle this time delay, existing parameter ranking, subset selection and estimation methods[3-5] were extended to treat the delay associated with the overhead piping as an additional unknown model parameter. Although, the resulting parameter estimates lead to better predictions on average compared to the model of Cui et al., there is still noticeable mismatch between the data and the model predictions. For example, Figure 2 shows dynamic model predictions and data for linear dimer and tetramer concentrations in the reactor obtained using a super-acid catalyst. Further parameter estimation studies are underway to determine whether current estimates correspond only to a local minimum for the optimization problem. In future, the model will be extended to account for formation and evaporation of cyclic oligomers. Please click Additional Files below to see the full abstract

A team effort: natural killer cells on the first leg of the tumor immunity relay race

Recent work by Böttcher and colleagues defines a new role for Natural Killer cells in the anti-tumor immune response, arriving early into the tumor microenvironment before passing the baton to DC1 dendritic cells. DC1 dendritic cells subsequently activate CD8+ T cells resulting in effective anti-tumor immunity. This work highlights the cooperative nature of anti-tumor immunity set in motion by Natural Killer cells, and immune evasion by tumors through their exclusion.National Cancer Institute (U.S.) (R00CA204595

Ist Fairer Handel Wirklich Fair?

Organisationen des Fairen Handels verfolgen das Ziel benachteiligten Produzenten in Entwicklungsländern faire Preise für deren Erzeugnisse zu zahlen. Dennoch ist es aus makro- und mikroökonomischer Sicht fraglich, ob die Zahlung eines Preisaufschlags wirklich effektiv für die betroffenen Produzenten ist. Am Beispiel des Bananenmarktes soll anhand einer Kosten-Nutzen-Analyse und der Analyse möglicher negativer Externalitäten des Fairen Handels auf nichtteilnehmende Produzenten die Frage erörtert werden, inwieweit dieses alternative Handelsmodell als „fair“ bezeichnet werden kann.Fairer Handel, Bananenmarkt, Kosten-Nutzen-Analyse, Verteilungsaspekte, negative Externalitäten

Navya3DSeg -- Navya 3D Semantic Segmentation Dataset & split generation for autonomous vehicles

Autonomous driving (AD) perception today relies heavily on deep learning based architectures requiring large scale annotated datasets with their associated costs for curation and annotation. The 3D semantic data are useful for core perception tasks such as obstacle detection and ego-vehicle localization. We propose a new dataset, Navya 3D Segmentation (Navya3DSeg), with a diverse label space corresponding to a large scale production grade operational domain, including rural, urban, industrial sites and universities from 13 countries. It contains 23 labeled sequences and 25 supplementary sequences without labels, designed to explore self-supervised and semi-supervised semantic segmentation benchmarks on point clouds. We also propose a novel method for sequential dataset split generation based on iterative multi-label stratification, and demonstrated to achieve a +1.2% mIoU improvement over the original split proposed by SemanticKITTI dataset. A complete benchmark for semantic segmentation task was performed, with state of the art methods. Finally, we demonstrate an active learning (AL) based dataset distillation framework. We introduce a novel heuristic-free sampling method called distance sampling in the context of AL. A detailed presentation on the dataset is available at https://www.youtube.com/watch?v=5m6ALIs-s20 .Comment: Submitted to RA-L. Version with supplementary material

Particle distribution and nuclear stopping in Au-Au collisions at sNN\sqrt{s_{NN}}=200 GeV

The transverse momentum distribution of produced charged particles is investigated for gold-gold collisions at $\sqrt{s_{NN}}=200$ GeV. A simple parameterization is suggested for the particle distribution based on the nuclear stopping effect. The model can fit very well both the transverse momentum distributions at different pseudo-rapidities and the pseudo-rapidity distributions at different centralities. The ratio of rapidity distributions for peripheral and central collisions is calculated and compared with the data.Comment: 5 pages in RevTeX, 3 eps figure

Brownian Motion in an N-scale periodic Potential

We study the problem of Brownian motion in a multiscale potential. The potential is assumed to have N+1 scales (i.e. N small scales and one macroscale) and to depend periodically on all the small scales. We show that for nonseparable potentials, i.e. potentials in which the microscales and the macroscale are fully coupled, the homogenized equation is an overdamped Langevin equation with multiplicative noise driven by the free energy, for which the detailed balance condition still holds. This means, in particular, that homogenized dynamics is reversible and that the coarse-grained Fokker–Planck equation is still a Wasserstein gradient flow with respect to the coarse-grained free energy. The calculation of the effective diffusion tensor requires the solution of a system of N coupled Poisson equations

Membrane distillation and membrane electrolysis of coal seam gas reverse osmosis brine for clean water extraction and NaOH production

Membrane distillation (MD) and membrane electrolysis (ME) were evaluated for simultaneous fresh water extraction and NaOH production from a mixture of NaCl and NaHCO3 to simulate the composition of coal seam gas (CSG) reverse osmosis (RO) brine. Experimental results demonstrate the potential of MD for producing fresh water and simultaneously concentrating CSG RO brine prior to the ME process. MD water flux was slightly reduced by the increased feed salinity and the decomposition of bicarbonate to CO2 during the concentration of CSG RO brine. MD operation of CSG RO brine at a concentration factor of 10 (90% water recovery) was achieved with distillate conductivity as low as 18 μS/cm, and without any observable membrane scaling. Exceeding the concentration factor of 10 could lead to deterioration in both water flux and distillate quality due to the precipitation of NaCl, NaHCO3, and Na2CO3 on the membrane. With respect to ME, current density and water circulation rates exerted strong influences on the ME process performance. Combining ME with MD reduced the thermal energy requirement of ME by 3 MJ per kg of NaOH produced and the thermal energy consumption of MD by 22 MJ per m3 of clean water extracted