Using Markov Models and Statistics to Learn, Extract, Fuse, and Detect Patterns in Raw Data

Many systems are partially stochastic in nature. We have derived data driven approaches for extracting stochastic state machines (Markov models) directly from observed data. This chapter provides an overview of our approach with numerous practical applications. We have used this approach for inferring shipping patterns, exploiting computer system side-channel information, and detecting botnet activities. For contrast, we include a related data-driven statistical inferencing approach that detects and localizes radiation sources.Comment: Accepted by 2017 International Symposium on Sensor Networks, Systems and Securit

Real world experience of response to pirfenidone in patients with idiopathic pulmonary fibrosis: a two centre retrospective study

Introduction: Pirfenidone has been shown to reduce the decline in forced vital capacity (FVC) compared to placebo in patients with idiopathic pulmonary fibrosis (IPF). Previous studies have suggested that patients with a more rapid decline in FVC during the period before starting pirfenidone experience the greatest benefit from treatment. The purpose of this retrospective observational study was to investigate the response to pirfenidone in IPF patients, comparing two groups stratified by the annual rate of decline in FVC % predicted prior to treatment. Methods: Using the rate of decline in FVC % predicted in the 12 months prior to pirfenidone, patients were stratified into slow (<5%) or rapid (≥5%) decliner groups. Comparisons in the lung function response to pirfenidone in these two groups were performed. Results: Pirfenidone resulted in no statistically significant reduction in the median annual rate of decline in FVC or FVC % predicted. In the rapid decliners, pirfenidone significantly reduced the median (IQR) annual rate of decline in FVC % predicted (-8.7 (-14.2 - -7.0) %/yr vs 2.0 (-7.1 - 6.0) %/yr; n=17; p<0.01). In the slow decliners, pirfenidone did not reduce the median (IQR) annual rate of decline in FVC % predicted (-1.3 (-3.2 - 1.3) %/yr vs -5.0 (-8.3 - -0.35) %/yr; n=17; p=0.028). Conclusions: We demonstrate the greater net effect of pirfenidone in IPF patients declining rapidly. We suggest that using an annual rate of decline in FVC of <5% and ≥5% may be useful in counselling patients with regard to pirfenidone treatment

Multicritical microscopic spectral correlators of hermitian and complex matrices

We find the microscopic spectral densities and the spectral correlators associated with multicritical behavior for both hermitian and complex matrix ensembles, and show their universality. We conjecture that microscopic spectral densities of Dirac operators in certain theories without spontaneous chiral symmetry breaking may belong to these new universality classes

A high stability semiconductor laser system for a 88^{88}Sr-based optical lattice clock

We describe a frequency stabilized diode laser at 698 nm used for high resolution spectroscopy of the 1S0-3P0 strontium clock transition. For the laser stabilization we use state-of-the-art symmetrically suspended optical cavities optimized for very low thermal noise at room temperature. Two-stage frequency stabilization to high finesse optical cavities results in measured laser frequency noise about a factor of three above the cavity thermal noise between 2 Hz and 11 Hz. With this system, we demonstrate high resolution remote spectroscopy on the 88Sr clock transition by transferring the laser output over a phase-noise-compensated 200 m-long fiber link between two separated laboratories. Our dedicated fiber link ensures a transfer of the optical carrier with frequency stability of 7 \cdot 10^{-18} after 100 s integration time, which could enable the observation of the strontium clock transition with an atomic Q of 10^{14}. Furthermore, with an eye towards the development of transportable optical clocks, we investigate how the complete laser system (laser+optics+cavity) can be influenced by environmental disturbances in terms of both short- and long-term frequency stability.Comment: 9 pages, 9 figures, submitted to Appl. Phys.

All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: minor corrections to some figures and captions, clarification of some points in the text, added references, added new paragraph with results on atom-resonator interactio

Theory of Two-Dimensional Quantum Heisenberg Antiferromagnets with a Nearly Critical Ground State

We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range N\'{e}el order. For N\'{e}el-ordered states, `nearly-critical' means that the ground state spin-stiffness, $\rho_s$, satisfies $\rho_s \ll J$, where $J$ is the nearest-neighbor exchange constant, while `nearly-critical' quantum-disordered ground states have a energy-gap, $\Delta$, towards excitations with spin-1, which satisfies $\Delta \ll J$. Under these circumstances, we show that the wavevector/frequency-dependent uniform and staggered spin susceptibilities, and the specific heat, are completely universal functions of just three thermodynamic parameters. Explicit results for the universal scaling functions are obtained by a $1/N$ expansion on the $O(N)$ quantum non-linear sigma model, and by Monte Carlo simulations. These calculations lead to a variety of testable predictions for neutron scattering, NMR, and magnetization measurements. Our results are in good agreement with a number of numerical simulations and experiments on undoped and lightly-doped $La_{2-\delta} Sr_{\delta}Cu O_4$.Comment: 81 pages, REVTEX 3.0, smaller updated version, YCTP-xxx

Sex Segregation and Salary Structure in Academia

This article reports a study of aggregate unit salary levels, within a major research university. We analyze these salary levels, as they are influenced by unit sex composition, and modified by unit attainment levels—where unit refers to the departments, colleges and schools, and other academic divisions of the university. We investigate three central issues of sex and salary, previously overlooked in salary studies of academic employees: Do high proportions of women depress men's unit salary levels ("competition" hypothesis)? Are women's salary levels higher in male-dominated, and lower in female-dominated, units ("concentration" hypothesis)? Are men salary-compensated for working with women ("compensation" hypothesis)? The findings support none of these hypotheses. Rather, the relationship between unit sex composition and salary rests upon the connection between units' composition and attainment levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69126/2/10.1177_073088848100800103.pd

Search for Colour Singlet and Colour Reconnection Effects in Hadronic Z Decays at LEP

A search is performed in symmetric 3-jet hadronic Z decay events for evidence of colour singlet production or colour reconnection effects. Asymmetries in the angular separation of particles are found to be sensitive indicators of such effects. Upper limits on the level of colour singlet production and colour reconnection effects are established for a variety of models