Sales tax as a source of federal and state revenue.

Thesis (M.B.A.)--Boston Universit

Incremental bounded model checking for embedded software

Program analysis is on the brink of mainstream usage in embedded systems development. Formal verification of behavioural requirements, finding runtime errors and test case generation are some of the most common applications of automated verification tools based on bounded model checking (BMC). Existing industrial tools for embedded software use an off-the-shelf bounded model checker and apply it iteratively to verify the program with an increasing number of unwindings. This approach unnecessarily wastes time repeating work that has already been done and fails to exploit the power of incremental SAT solving. This article reports on the extension of the software model checker CBMC to support incremental BMC and its successful integration with the industrial embedded software verification tool BTC EMBEDDED TESTER. We present an extensive evaluation over large industrial embedded programs, mainly from the automotive industry. We show that incremental BMC cuts runtimes by one order of magnitude in comparison to the standard non-incremental approach, enabling the application of formal verification to large and complex embedded software. We furthermore report promising results on analysing programs with arbitrary loop structure using incremental BMC, demonstrating its applicability and potential to verify general software beyond the embedded domain

A Cautionary Tale: MARVELS Brown Dwarf Candidate Reveals Itself To Be A Very Long Period, Highly Eccentric Spectroscopic Stellar Binary

We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV) measurements (R ~ <30,000), this particular stellar binary mimics a single-lined binary with an RV signal that would be induced by a brown dwarf companion (Msin(i)~50 M_Jup) to a solar-type primary. At least three properties of this system allow it to masquerade as a single star with a very low-mass companion: its large eccentricity (e~0.8), its relatively long period (P~238 days), and the approximately perpendicular orientation of the semi-major axis with respect to the line of sight (omega~189 degrees). As a result of these properties, for ~95% of the orbit the two sets of stellar spectral lines are completely blended, and the RV measurements based on centroiding on the apparently single-lined spectrum is very well fit by an orbit solution indicative of a brown dwarf companion on a more circular orbit (e~0.3). Only during the ~5% of the orbit near periastron passage does the true, double-lined nature and large RV amplitude of ~15 km/s reveal itself. The discovery of this binary system is an important lesson for RV surveys searching for substellar companions; at a given resolution and observing cadence, a survey will be susceptible to these kinds of astrophysical false positives for a range of orbital parameters. Finally, for surveys like MARVELS that lack the resolution for a useful line bisector analysis, it is imperative to monitor the peak of the cross-correlation function for suspicious changes in width or shape, so that such false positives can be flagged during the candidate vetting process.Comment: 16 pages, 11 figures, 6 table

A phenome-wide comparative analysis of genetic discordance between obesity and type 2 diabetes

Obesity and type 2 diabetes are causally related, yet there is considerable heterogeneity in the consequences of both conditions and the mechanisms of action are poorly defined. Here we show a genetic-driven approach defining two obesity profiles that convey highly concordant and discordant diabetogenic effects. We annotate and then compare association signals for these profiles across clinical and molecular phenotypic layers. Key differences are identified in a wide range of traits, including cardiovascular mortality, fat distribution, liver metabolism, blood pressure, specific lipid fractions and blood levels of proteins involved in extracellular matrix remodelling. We find marginal differences in abundance of Bacteroidetes and Firmicutes bacteria in the gut. Instrumental analyses reveal prominent causal roles for waist-to-hip ratio, blood pressure and cholesterol content of high-density lipoprotein particles in the development of diabetes in obesity. We prioritize 17 genes from the discordant signature that convey protection against type 2 diabetes in obesity, which may represent logical targets for precision medicine approaches.</p

Very Low-Mass Stellar and Substellar Companions to Solar-Like Stars from MARVELS I: A Low Mass Ratio Stellar Companion to TYC 4110-01037-1 in a 79-day Orbit

TYC 4110-01037-1 has a low-mass stellar companion, whose small mass ratio and short orbital period are atypical amongst solar-like (Teff ~< 6000 K) binary systems. Our analysis of TYC 4110-01037-1 reveals it to be a moderately aged (~<5 Gyr) solar-like star having a mass of 1.07 +/- 0.08 MSun and radius of 0.99 +/- 0.18 RSun. We analyze 32 radial velocity measurements from the SDSS-III MARVELS survey as well as 6 supporting radial velocity measurements from the SARG spectrograph on the 3.6m TNG telescope obtained over a period of ~2 years. The best Keplerian orbital fit parameters were found to have a period of 78.994 +/- 0.012 days, an eccentricity of 0.1095 +/- 0.0023, and a semi-amplitude of 4199 +/- 11 m/s. We determine the minimum companion mass (if sin i = 1) to be 97.7 +/- 5.8 MJup. The system's companion to host star mass ratio, >0.087 +/- 0.003, places it at the lowest end of observed values for short period stellar companions to solar-like (Teff ~< 6000 K) stars. One possible way to create such a system would be if a triple-component stellar multiple broke up into a short period, low q binary during the cluster dispersal phase of its lifetime. A candidate tertiary body has been identified in the system via single-epoch, high contrast imagery. If this object is confirmed to be co-moving, we estimate it would be a dM4 star. We present these results in the context of our larger-scale effort to constrain the statistics of low mass stellar and brown dwarf companions to FGK-type stars via the MARVELS survey.Comment: 22 pages; accepted in A

Very Low Mass Stellar and Substellar Companions to Solar-Like Stars From MARVELS V: A Low Eccentricity Brown Dwarf from the Driest Part of the Desert, MARVELS-6b

We describe the discovery of a likely brown dwarf (BD) companion with a minimum mass of 31.7 +/- 2.0 M_Jup to GSC 03546-01452 from the MARVELS radial velocity survey, which we designate as MARVELS-6b. For reasonable priors, our analysis gives a probability of 72% that MARVELS-6b has a mass below the hydrogen-burning limit of 0.072 M_Sun, and thus it is a high-confidence BD companion. It has a moderately long orbital period of 47.8929 +0.0063/-0.0062 days with a low eccentricty of 0.1442 +0.0078/-0.0073, and a semi-amplitude of 1644 +12/-13 m/s. Moderate resolution spectroscopy of the host star has determined the following parameters: T_eff = 5598 +/- 63, log g = 4.44 +/- 0.17, and [Fe/H] = +0.40 +/- 0.09. Based upon these measurements, GSC 03546-01452 has a probable mass and radius of M_star = 1.11 +/- 0.11 M_Sun and R_star = 1.06 +/- 0.23 R_Sun with an age consistent with less than ~6 Gyr at a distance of 219 +/- 21 pc from the Sun. Although MARVELS-6b is not observed to transit, we cannot definitively rule out a transiting configuration based on our observations. There is a visual companion detected with Lucky Imaging at 7.7 arcsec from the host star, but our analysis shows that it is not bound to this system. The minimum mass of MARVELS-6b exists at the minimum of the mass functions for both stars and planets, making this a rare object even compared to other BDs.Comment: 15 pages, 15 figures, 5 tables. Accepted for publication in The Astronomical Journa

Measurement of Exclusive π0\pi^0 Electroproduction Structure Functions and their Relationship to Transversity GPDs

Exclusive $\pi^0$ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in $Q^2$, $x_B$, $t$, and $\phi_\pi$, in the $Q^2$ range from 1.0 to 4.6 GeV$^2$,\ $-t$ up to 2 GeV$^2$, and $x_B$ from 0.1 to 0.58. Structure functions $\sigma_T +\epsilon \sigma_L, \sigma_{TT}$ and $\sigma_{LT}$ were extracted as functions of $t$ for each of 17 combinations of $Q^2$ and $x_B$. The data were compared directly with two handbag-based calculations including both longitudinal and transversity GPDs. Inclusion of only longitudinal GPDs very strongly underestimates $\sigma_T +\epsilon \sigma_L$ and fails to account for $\sigma_{TT}$ and $\sigma_{LT}$, while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity flip and helicity non-flip processes. The results confirm that exclusive $\pi^0$ electroproduction offers direct experimental access to the transversity GPDs.Comment: 6 pages, 2 figure

Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)

\We present the sixth catalog of Kepler candidate planets based on nearly 4 years of high precision photometry. This catalog builds on the legacy of previous catalogs released by the Kepler project and includes 1493 new Kepler Objects of Interest (KOIs) of which 554 are planet candidates, and 131 of these candidates have best fit radii <1.5 R_earth. This brings the total number of KOIs and planet candidates to 7305 and 4173 respectively. We suspect that many of these new candidates at the low signal-to-noise limit may be false alarms created by instrumental noise, and discuss our efforts to identify such objects. We re-evaluate all previously published KOIs with orbital periods of >50 days to provide a consistently vetted sample that can be used to improve planet occurrence rate calculations. We discuss the performance of our planet detection algorithms, and the consistency of our vetting products. The full catalog is publicly available at the NASA Exoplanet Archive.Comment: 18 pages, to be published in the Astrophysical Journal Supplement Serie