Online Convex Optimization with Binary Constraints

We consider online optimization with binary decision variables and convex loss functions. We design a new algorithm, binary online gradient descent (bOGD) and bound its expected dynamic regret. We provide a regret bound that holds for any time horizon and a specialized bound for finite time horizons. First, we present the regret as the sum of the relaxed, continuous round optimum tracking error and the rounding error of our update in which the former asymptomatically decreases with time under certain conditions. Then, we derive a finite-time bound that is sublinear in time and linear in the cumulative variation of the relaxed, continuous round optima. We apply bOGD to demand response with thermostatically controlled loads, in which binary constraints model discrete on/off settings. We also model uncertainty and varying load availability, which depend on temperature deadbands, lockout of cooling units and manual overrides. We test the performance of bOGD in several simulations based on demand response. The simulations corroborate that the use of randomization in bOGD does not significantly degrade performance while making the problem more tractable

American Anti-Welfare Right-Wing Populism: The Case of Bucktown

Is there support for voluntary sterilization incentives in the U.S.? Nine semi-structured interviews were conducted with a snowball sample of four families spanning three generations in Bucktown, a 95% white, middle-class neighborhood which sent David Duke, former Grand Wizard of the Ku Klux Klan, to the Louisiana House of Representatives in 1989. Interviews explain support and opposition to current Louisiana State Representative John LaBruzzo\u27s policy suggestion to end generational welfare by offering citizens $1000 in exchange for having their fallopian tubes tied or receiving vasectomies. Most respondents expressed that the sterilization proposal was targeted at low-income blacks. Although work ethic deficiency was used to frame poverty and welfare-dependency, support and opposition for the proposal was ultimately divided along racial ideological lines. Although Bucktonians have disassociated themselves from Duke and are upwardly mobile socio-economically, right-wing populist ideology remains salient

Novel Advancements for Improving Sprout Safety

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the sprouting environment, antimicrobial treatments, and the presence of pathogens on the microbiota of sprouts. Using a novel strain of Serratia plymuthica, the growth of Salmonella spp. or E. coli O157:H7 were either suppressed or inhibited on sprouts that were co-inoculated with S. plymuthica and either pathogen. A novel carvacrol nanoemulsion was developed and tested for its efficacy against contaminated sprouting seeds and storage stability. The initial formulation was able to inactive low levels (≤ 3 log CFU/g) of S. Enteritidis or E. coli O157:H7 on mung beans, alfalfa, and radish sprouting seeds, but not broccoli. It was found that pH and high levels (≥10% v/v) of organic load significantly influenced the antimicrobial properties of the emulsion. With the addition of 50 mM acetic or levulinic acid, the treatment was able to inactivate 4 log CFU/g and 2 log CFU/g of pathogens on mung beans or broccoli seeds, respectively. The emulsion was found to be stable and still effective up to 30 days of storage at room temperature. Microbial population studies, utilizing a terminal restricted fragment length polymorphism analysis, showed that the microbiota differed between sprouting seed varieties. During the course of aseptic germination, there was a population shift which resulted in a less diverse population, mainly compose of Pseudomonadaceae. Sprouts that were commercially germinated had a more diverse population than aseptically germinated sprouts when seeds from the same distributer were used, suggesting that the sprouting environment can influence the final microbiota. The presence of pathogens resulted in a microbiota predominantly composed of Pseudomonadaceae and Enterobacteriaceae. Sprouting seeds that were treated with the carvacrol nanoemulsion resulted in a population comprised of mostly Pseudomonadaceae. Seeds that were initially contaminated with S. Enteritidis and treated with the carvacrol nanoemulsion had no detectable Salmonella restricted fragments or viable cells, suggesting complete inactivation of the pathogen. Sprouts will continue to a food for health conscious consumers. They will also be scrutinized for their chronic correlation with foodborne pathogens such as Salmonella spp. and E. coli O157:H7. It is vital that research continues in the areas of prevention, disinfection, and detection of pathogens on produce

American Anti-Welfare Right-Wing Populism: The Case of Bucktown

Is there support for voluntary sterilization incentives in the U.S.? Nine semi-structured interviews were conducted with a snowball sample of four families spanning three generations in Bucktown, a 95% white, middle-class neighborhood which sent David Duke, former Grand Wizard of the Ku Klux Klan, to the Louisiana House of Representatives in 1989. Interviews explain support and opposition to current Louisiana State Representative John LaBruzzo\u27s policy suggestion to end generational welfare by offering citizens $1000 in exchange for having their fallopian tubes tied or receiving vasectomies. Most respondents expressed that the sterilization proposal was targeted at low-income blacks. Although work ethic deficiency was used to frame poverty and welfare-dependency, support and opposition for the proposal was ultimately divided along racial ideological lines. Although Bucktonians have disassociated themselves from Duke and are upwardly mobile socio-economically, right-wing populist ideology remains salient

An Application of M-matrices to Preserve Bounded Positive Solutions to the Evolution Equations of Biofilm Models

In this work, we design a linear, two step implicit finite difference method to approximate the solutions of a biological system that describes the interaction between a microbial colony and a surrounding substrate. Three separate models are analyzed, all of which can be described as systems of partial differential equations (PDE)s with nonlinear diffusion and reaction, where the biological colony grows and decays based on the substrate bioavailability. The systems under investigation are all complex models describing the dynamics of biological films. In view of the difficulties to calculate analytical solutions of the models, we design here a numerical technique to consistently approximate the system evolution dynamics, guaranteeing that nonnegative initial conditions will evolve uniquely into new, nonnegative approximations. This property of our technique is established using the theory of M-matrices, which are nonsingular matrices where all the entries of their inverses are positive numbers. We provide numerical simulations to evince the preservation of the nonnegative character of solutions under homogeneous Dirichlet and Neumann boundary conditions. The computational results suggest that the method proposed in this work is stable, and that it also preserves the bounded character of the discrete solutions

Phonon Band Structure and Thermal Transport Correlation in a Layered Diatomic Crystal

To elucidate the relationship between a crystal's structure, its thermal conductivity, and its phonon dispersion characteristics, an analysis is conducted on layered diatomic Lennard-Jones crystals with various mass ratios. Lattice dynamics theory and molecular dynamics simulations are used to predict the phonon dispersion curves and the thermal conductivity. The layered structure generates directionally dependent thermal conductivities lower than those predicted by density trends alone. The dispersion characteristics are quantified using a set of novel band diagram metrics, which are used to assess the contributions of acoustic phonons and optical phonons to the thermal conductivity. The thermal conductivity increases as the extent of the acoustic modes increases, and decreases as the extent of the stop bands increases. The sensitivity of the thermal conductivity to the band diagram metrics is highest at low temperatures, where there is less anharmonic scattering, indicating that dispersion plays a more prominent role in thermal transport in that regime. We propose that the dispersion metrics (i) provide an indirect measure of the relative contributions of dispersion and anharmonic scattering to the thermal transport, and (ii) uncouple the standard thermal conductivity structure-property relation to that of structure-dispersion and dispersion-property relations, providing opportunities for better understanding of the underlying physical mechanisms and a potential tool for material design.Comment: 30 pages, 10 figure

Granular packings with moving side walls

The effects of movement of the side walls of a confined granular packing are studied by discrete element, molecular dynamics simulations. The dynamical evolution of the stress is studied as a function of wall movement both in the direction of gravity as well as opposite to it. For all wall velocities explored, the stress in the final state of the system after wall movement is fundamentally different from the original state obtained by pouring particles into the container and letting them settle under the influence of gravity. The original packing possesses a hydrostatic-like region at the top of the container which crosses over to a depth-independent stress. As the walls are moved in the direction opposite to gravity, the saturation stress first reaches a minimum value independent of the wall velocity, then increases to a steady-state value dependent on the wall-velocity. After wall movement ceases and the packing reaches equilibrium, the stress profile fits the classic Janssen form for high wall velocities, while it has some deviations for low wall velocities. The wall movement greatly increases the number of particle-wall and particle-particle forces at the Coulomb criterion. Varying the wall velocity has only small effects on the particle structure of the final packing so long as the walls travel a similar distance.Comment: 11 pages, 10 figures, some figures in colo