Service in Your Neighborhood: Fairness in Center Location

When selecting locations for a set of centers, standard clustering algorithms may place unfair burden on some individuals and neighborhoods. We formulate a fairness concept that takes local population densities into account. In particular, given k centers to locate and a population of size n, we define the "neighborhood radius" of an individual i as the minimum radius of a ball centered at i that contains at least n/k individuals. Our objective is to ensure that each individual has a center that is within at most a small constant factor of her neighborhood radius. We present several theoretical results: We show that optimizing this factor is NP-hard; we give an approximation algorithm that guarantees a factor of at most 2 in all metric spaces; and we prove matching lower bounds in some metric spaces. We apply a variant of this algorithm to real-world address data, showing that it is quite different from standard clustering algorithms and outperforms them on our objective function and balances the load between centers more evenly

Grid Computing for LHC and Methods for W Boson Mass Measurement at CMS

The W boson mass is an important parameter of the Standard Model (SM) of particle physics. The experiments at the Large Hadron Collider (LHC) focus, amongst other goals, on checking the consistency of the SM; for this, the W boson mass is a vital parameter. This thesis presents a feasibility study of two methods for measuring the W boson mass with the Compact Muon Solenoid (CMS) detector; the simulation of proton-proton collisions was performed using grid computing tools

A Causal-Comparative Study of Strategies Designed to Decrease Discipline Incidents in Urban Elementary Schools

Urban schools have struggled to overcome the achievement gap, including the most recent issue of inequity of discipline within the schools. A causal-comparative design was used to find whether the varying strategies alleged to successfully decrease discipline issues are as effective within urban elementary schools as in suburban schools. The sample included 790 public, elementary, urban or suburban schools within the state of Ohio that drew on ex post facto data of discipline incidents and enrollment from the school years of 2017-2018 and 2018-2019 acquired from the Ohio Department of Education. The large sample of schools in both urban and suburban groups allowed for stronger validity. The researcher used an independent samples t-test as the main analysis procedure, but there was a violation of Levene’s test of homogeneity of variance. For this reason, the Mann-Whitney U test was used to verify the t-test results. In both analyses, a comparison of the urban schools and the suburban schools was shown to have no statistically significant differences in the decline of discipline incidents per student between the two groups. From these results, the conclusion was that the urban schools have success similar to suburban schools using the state mandated PBIS strategies. Further research should include a closer examination of which strategies are the most effective

In-Medium Spectral Functions of Vector- and Axial-Vector Mesons from the Functional Renormalization Group

In this work we present first results on vector and axial-vector meson spectral functions as obtained by applying the non-perturbative functional renormalization group approach to an effective low-energy theory motivated by the gauged linear sigma model. By using a recently proposed analytic continuation method, we study the in-medium behavior of the spectral functions of the $\rho$ and $a_1$ mesons in different regimes of the phase diagram. In particular, we demonstrate explicitly how these spectral functions degenerate at high temperatures as well as at large chemical potentials, as a consequence of the restoration of chiral symmetry. In addition, we also compute the momentum dependence of the $\rho$ and $a_1$ spectral functions and discuss the various time-like and space-like processes that can occur.Comment: 18 pages, 13 figures, 1 tabl

Spectral Functions from the Functional Renormalization Group

We present results for in-medium spectral functions obtained within the Functional Renormalization Group framework. The analytic continuation from imaginary to real time is performed in a well-defined way on the level of the flow equations. Based on this recently developed method, results for the sigma and the pion spectral function for the quark-meson model are shown at finite temperature, finite quark-chemical potential and finite spatial momentum. It is shown how these spectral function become degenreate at high temperatures due to the restoration of chiral symmetry. In addition, results for vector- and axial-vector meson spectral functions are shown using a gauged linear sigma model with quarks. The degeneration of the $\rho$ and the $a_1$ spectral function as well as the behavior of their pole masses is discussed.Comment: CPOD 2017 Proceeding