431 research outputs found
Scaling Bounded Model Checking By Transforming Programs With Arrays
Bounded Model Checking is one the most successful techniques for finding bugs
in program. However, model checkers are resource hungry and are often unable to
verify programs with loops iterating over large arrays.We present a
transformation that enables bounded model checkers to verify a certain class of
array properties. Our technique transforms an array-manipulating (ANSI-C)
program to an array-free and loop-free (ANSI-C) program thereby reducing the
resource requirements of a model checker significantly. Model checking of the
transformed program using an off-the-shelf bounded model checker simulates the
loop iterations efficiently. Thus, our transformed program is a sound
abstraction of the original program and is also precise in a large number of
cases - we formally characterize the class of programs for which it is
guaranteed to be precise. We demonstrate the applicability and usefulness of
our technique on both industry code as well as academic benchmarks
Rich Counter-Examples for Temporal-Epistemic Logic Model Checking
Model checking verifies that a model of a system satisfies a given property,
and otherwise produces a counter-example explaining the violation. The verified
properties are formally expressed in temporal logics. Some temporal logics,
such as CTL, are branching: they allow to express facts about the whole
computation tree of the model, rather than on each single linear computation.
This branching aspect is even more critical when dealing with multi-modal
logics, i.e. logics expressing facts about systems with several transition
relations. A prominent example is CTLK, a logic that reasons about temporal and
epistemic properties of multi-agent systems. In general, model checkers produce
linear counter-examples for failed properties, composed of a single computation
path of the model. But some branching properties are only poorly and partially
explained by a linear counter-example.
This paper proposes richer counter-example structures called tree-like
annotated counter-examples (TLACEs), for properties in Action-Restricted CTL
(ARCTL), an extension of CTL quantifying paths restricted in terms of actions
labeling transitions of the model. These counter-examples have a branching
structure that supports more complete description of property violations.
Elements of these counter-examples are annotated with parts of the property to
give a better understanding of their structure. Visualization and browsing of
these richer counter-examples become a critical issue, as the number of
branches and states can grow exponentially for deeply-nested properties.
This paper formally defines the structure of TLACEs, characterizes adequate
counter-examples w.r.t. models and failed properties, and gives a generation
algorithm for ARCTL properties. It also illustrates the approach with examples
in CTLK, using a reduction of CTLK to ARCTL. The proposed approach has been
implemented, first by extending the NuSMV model checker to generate and export
branching counter-examples, secondly by providing an interactive graphical
interface to visualize and browse them.Comment: In Proceedings IWIGP 2012, arXiv:1202.422
Analysis of hadronic transitions in Υ(3S) decays
This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.49.40.Using the CLEO II detector, we have measured the branching fractions for Υ(3S)→ππΥ(1S), Υ(3S)→ππΥ(2S), and the cascade Υ(3S)→Υ(2S)+X, Υ(2S)→π+π−Υ(1S), analyzing the exclusive mode where the daughter Υ state decays to a e(+)e(−) or μ(+)μ(−) pair, as well as the inclusive π(+)π(−) transitions where the final Υ state decays into hadrons. Properties of the ππ system are analyzed. Searches for the cascade decay Υ(3S)→π+π−h(b), h(b)→γη(b) and Υ(3S)→π0h(b) were also performed
Thermal based remediation technologies for soil and groundwater: a review
Thermal remediation technologies are fast and effective tools for the remediation of contaminated soils and sediments. Nevertheless, the high energy consumption and the effect of high temperature on the soil properties may hinder the wide applications of thermal remediation methods. This review highlights the recent studies focused on thermal remediation. Eight types of thermal remediation processes are discussed, including incineration, thermal desorption, stream enhanced extraction, electrical resistance heating, microwave heating, smoldering, vitrification, and pyrol-ysis. In addition, the combination of thermal remediation with other remediation technologies is presented. Finally, thermal remediation sustainability is evaluated in terms of energy efficiency and their impact on soil properties. The developments of the past decade show that thermal-based technologies are quite effective in terms of contaminant removal but that these technologies are associated with high energy use and costs and can has an adverse impact on soil properties. Nonetheless, it is anticipated that continued research on thermally based technologies can increase their sustainability and expand their applications. Low temperature thermal desorption is a prom-ising remediation technology in terms of land use and energy cost as it has no adverse effect on soil function after treatment and low temperature is required. Overall, selecting the sustainable remediation technology depends on the contaminant properties, soil properties and predicted risk level. © 2022 Desalination Publications. All rights reserved
Search for CP violation in D0 and D+ decays
A high statistics sample of photoproduced charm particles from the FOCUS
(E831) experiment at Fermilab has been used to search for CP violation in the
Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We
have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/-
0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) =
+0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second
error is systematic. These asymmetries are consistent with zero with smaller
errors than previous measurements.Comment: 12 pages, 4 figure
New FOCUS results on charm mixing and CP violation
We present a summary of recent results on CP violation and mixing in the
charm quark sector based on a high statistics sample collected by
photoproduction experiment FOCUS (E831 at Fermilab). We have measured the
difference in lifetimes for the decays: and . This translates into a measurement of the mixing parameter in
the \d0d0 system, under the assumptions that is an equal mixture of
CP odd and CP even eigenstates, and CP violation is negligible in the neutral
charm meson system. We verified the latter assumption by searching for a CP
violating asymmetry in the Cabibbo suppressed decay modes , and . We show preliminary
results on a measurement of the branching ratio .Comment: 9 pages, 6 figures, requires espcrc2.sty. Presented by S.Bianco at
CPConf2000, September 2000, Ferrara (Italy). In this revision, fixed several
stylistic flaws, add two significant references, fixed a typo in Tab.
The Target Silicon Detector for the FOCUS Spectrometer
We describe a silicon microstrip detector interleaved with segments of a
beryllium oxide target which was used in the FOCUS photoproduction experiment
at Fermilab. The detector was designed to improve the vertex resolution and to
enhance the reconstruction efficiency of short-lived charm particles.Comment: 18 pages, 14 figure
Experimental evidence for a light and broad scalar resonance in decay
From a sample of decay, we find
. Using a coherent amplitude analysis
to fit the Dalitz plot of this decays, we find strong evidence that a scalar
resonance of mass MeV/ and width MeV/ accounts for approximately half of all decays.Comment: 10 pages, 3 eps figure
Measurement of the Ds Lifetime
We report the results of a precise measurement of the Ds meson lifetime based
on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm
hadroproduction experiment E791 at Fermilab. Using an unbinned maximum
likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps.
The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25
+/- 0.04. This result differs from unity by six standard deviations, indicating
significantly different lifetimes for the Ds and the D0.Comment: 12 pages, 3 figures, 2 table. LaTe
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