838 research outputs found
SmartBugs 2.0: An Execution Framework for Weakness Detection in Ethereum Smart Contracts
Smart contracts are blockchain programs that often handle valuable assets.
Writing secure smart contracts is far from trivial, and any vulnerability may
lead to significant financial losses. To support developers in identifying and
eliminating vulnerabilities, methods and tools for the automated analysis have
been proposed. However, the lack of commonly accepted benchmark suites and
performance metrics makes it difficult to compare and evaluate such tools.
Moreover, the tools are heterogeneous in their interfaces and reports as well
as their runtime requirements, and installing several tools is time-consuming.
In this paper, we present SmartBugs 2.0, a modular execution framework. It
provides a uniform interface to 19 tools aimed at smart contract analysis and
accepts both Solidity source code and EVM bytecode as input. After describing
its architecture, we highlight the features of the framework. We evaluate the
framework via its reception by the community and illustrate its scalability by
describing its role in a study involving 3.25 million analyses
Deep multiband surface photometry on star forming galaxies: II. A volume limited sample of 21 emission lines galaxies
We present deep surface photometry of a volume--limited sample of 21 UM
emission line galaxies in broadband optical UBVRI and near infra-red (NIR) HKs
filters. The sample comprises 19 blue compact galaxies (BCGs) and two spirals.
For some targets the exposure times are the deepest to date. For the BCG UM462
we observe a previously undetected second disk component beyond a surface
brightness level of mu_B=26 mag arcsec^{-2}. This is a true low surface
brightness component with central surface brightness mu_0=24.1 mag arcsec^{-2}
and scale length h_r=1.5 kpc. All BCGs are dwarfs, with M_B>=-18, and very
compact, with an average scale length of h_r~1 kpc. We separate the burst and
host populations for each galaxy and compare them to stellar evolutionary
models with and without nebular emission contribution. We also measure the
A_{180} asymmetry in all filters and detect a shift from optical to NIR in the
average asymmetry of the sample. This shift seems to be correlated with the
morphological class of the BCGs. Using the color-asymmetry relation, we
identify five BCGs in the sample as mergers, which is confirmed by their
morphological class. Though clearly separated from normal galaxies in the
concentration-asymmetry parameter space, we find that it is not possible to
distinguish luminous starbursting BCGs from the merely star forming low
luminosity BCGs.Comment: 48 pages, 39 figures, submitte
AGC 226067: A possible interacting low-mass system
We present Arecibo, GBT, VLA and WIYN/pODI observations of the ALFALFA source
AGC 226067. Originally identified as an ultra-compact high velocity cloud and
candidate Local Group galaxy, AGC 226067 is spatially and kinematically
coincident with the Virgo cluster, and the identification by multiple groups of
an optical counterpart with no resolved stars supports the interpretation that
this systems lies at the Virgo distance (D=17 Mpc). The combined observations
reveal that the system consists of multiple components: a central HI source
associated with the optical counterpart (AGC 226067), a smaller HI-only
component (AGC 229490), a second optical component (AGC 229491), and extended
low surface brightness HI. Only ~1/4 of the single-dish HI emission is
associated with AGC 226067; as a result, we find M_HI/L_g ~ 6 Msun/Lsun, which
is lower than previous work. At D=17 Mpc, AGC 226067 has an HI mass of 1.5 x
10^7 Msun and L_g = 2.4 x 10^6 Lsun, AGC 229490 (the HI-only component) has
M_HI = 3.6 x 10^6 Msun, and AGC 229491 (the second optical component) has L_g =
3.6 x 10^5 Lsun. The nature of this system of three sources is uncertain: AGC
226067 and AGC 229490 may be connected by an HI bridge, and AGC 229490 and AGC
229491 are separated by only 0.5'. The current data do not resolve the HI in
AGC 229490 and its origin is unclear. We discuss possible scenarios for this
system of objects: an interacting system of dwarf galaxies, accretion of
material onto AGC 226067, or stripping of material from AGC 226067.Comment: Accepted for publication in A&A. 6 pages, 4 figure
The Tully-Fisher Relation and H_not
The use of the Tully-Fisher (TF) relation for the determination of the Hubble
Constant relies on the availability of an adequate template TF relation and of
reliable primary distances. Here we use a TF template relation with the best
available kinematical zero-point, obtained from a sample of 24 clusters of
galaxies extending to cz ~ 9,000 km/s, and the most recent set of Cepheid
distances for galaxies fit for TF use. The combination of these two ingredients
yields H_not = 69+/-5 km/(s Mpc). The approach is significantly more accurate
than the more common application with single cluster (e.g. Virgo, Coma)
samples.Comment: 10 pages, including 2 figures and 1 table; uses AAS LaTex. Submitted
to ApJ Letter
The Hamburg/SAO survey for emission-line galaxies. VI. The sixth list of 126 galaxies
We present the sixth list with results of the Hamburg/SAO Survey for
Emission-Line Galaxies. The final list resulted from follow-up spectroscopy
conducted with the 4.5m MMT telescope in 1996, and with 2.2m CAHA and 6m SAO
telescopes in 2000 to 2003. The data of this snap-shot spectroscopy survey
confirmed 134 emission-line objects out of 182 observed candidates and allowed
their quantitative spectral classification and redshift determination. We
classify 73 emission-line objects as definite or probable blue compact or HII
galaxies (BCG), 8 as QSOs, 4 as Seyfert 1 and 2 galaxies. 30 low-excitation
objects were classified as definite or probable starburst nuclei (SBN), 3 as
dwarf amorphous nuclei starburst galaxies (DANS) and 2 as LINERs. Due to the
low signal-to-noise ratio we could not classify 14 ELGs (NON). For another 9
galaxies we did not detect any significant emission lines. For 98 emission-line
galaxies, the redshifts and/or line intensities are determined for the first
time. For the remaining 28 previously-known ELGs we give either improved data
the line intensities or some independent measurements. The detection rate of
ELGs is ~70%. This paper completes the classification of strong-lined ELGs
found in the zone of the Hamburg/SAO survey. Together with previously known
BCG/HII galaxies in this zone, this sample of ~500 objects is the largest to
date in a well bound region.Comment: 18 pages, including 8 tables and 1 figure. Plots of the spectra of
126 ELGs are in a separate 13-page Appendix. Accepted for publication in
Astron.Astrophys. Full paper with full-resolution figures is available at
http://www.eso.org/~akniaze
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