6,356 research outputs found
Word-level Symbolic Trajectory Evaluation
Symbolic trajectory evaluation (STE) is a model checking technique that has
been successfully used to verify industrial designs. Existing implementations
of STE, however, reason at the level of bits, allowing signals to take values
in {0, 1, X}. This limits the amount of abstraction that can be achieved, and
presents inherent limitations to scaling. The main contribution of this paper
is to show how much more abstract lattices can be derived automatically from
RTL descriptions, and how a model checker for the general theory of STE
instantiated with such abstract lattices can be implemented in practice. This
gives us the first practical word-level STE engine, called STEWord. Experiments
on a set of designs similar to those used in industry show that STEWord scales
better than word-level BMC and also bit-level STE.Comment: 19 pages, 3 figures, 2 tables, full version of paper in International
Conference on Computer-Aided Verification (CAV) 201
A Faithful Semantics for Generalised Symbolic Trajectory Evaluation
Generalised Symbolic Trajectory Evaluation (GSTE) is a high-capacity formal
verification technique for hardware. GSTE uses abstraction, meaning that
details of the circuit behaviour are removed from the circuit model. A
semantics for GSTE can be used to predict and understand why certain circuit
properties can or cannot be proven by GSTE. Several semantics have been
described for GSTE. These semantics, however, are not faithful to the proving
power of GSTE-algorithms, that is, the GSTE-algorithms are incomplete with
respect to the semantics.
The abstraction used in GSTE makes it hard to understand why a specific
property can, or cannot, be proven by GSTE. The semantics mentioned above
cannot help the user in doing so. The contribution of this paper is a faithful
semantics for GSTE. That is, we give a simple formal theory that deems a
property to be true if-and-only-if the property can be proven by a GSTE-model
checker. We prove that the GSTE algorithm is sound and complete with respect to
this semantics
Coverage measurement for software application level verification using symbolic trajectory evaluation techniques
Copyright © 2004 IEEEDesign verification of a systems-on-a-chip is a bottleneck for hardware design projects. A new solution is a design verification methodology that applies coverage driven verification at the embedded software application level. This methodology currently lacks an appropriate coverage measurement technique. This paper proposes a new coverage model for the software application level. Using this coverage model, a novel technique to represent and measure coverage is described. This technique uses ideas such as control graph structures and checking algorithms to estimate the completeness of software application verification.Adriel Cheng, Atanas Parashkevov, Cheng-Chew Li
Reach Set Approximation through Decomposition with Low-dimensional Sets and High-dimensional Matrices
Approximating the set of reachable states of a dynamical system is an
algorithmic yet mathematically rigorous way to reason about its safety.
Although progress has been made in the development of efficient algorithms for
affine dynamical systems, available algorithms still lack scalability to ensure
their wide adoption in the industrial setting. While modern linear algebra
packages are efficient for matrices with tens of thousands of dimensions,
set-based image computations are limited to a few hundred. We propose to
decompose reach set computations such that set operations are performed in low
dimensions, while matrix operations like exponentiation are carried out in the
full dimension. Our method is applicable both in dense- and discrete-time
settings. For a set of standard benchmarks, it shows a speed-up of up to two
orders of magnitude compared to the respective state-of-the art tools, with
only modest losses in accuracy. For the dense-time case, we show an experiment
with more than 10.000 variables, roughly two orders of magnitude higher than
possible with previous approaches
On Model Based Synthesis of Embedded Control Software
Many Embedded Systems are indeed Software Based Control Systems (SBCSs), that
is control systems whose controller consists of control software running on a
microcontroller device. This motivates investigation on Formal Model Based
Design approaches for control software. Given the formal model of a plant as a
Discrete Time Linear Hybrid System and the implementation specifications (that
is, number of bits in the Analog-to-Digital (AD) conversion)
correct-by-construction control software can be automatically generated from
System Level Formal Specifications of the closed loop system (that is, safety
and liveness requirements), by computing a suitable finite abstraction of the
plant.
With respect to given implementation specifications, the automatically
generated code implements a time optimal control strategy (in terms of set-up
time), has a Worst Case Execution Time linear in the number of AD bits , but
unfortunately, its size grows exponentially with respect to . In many
embedded systems, there are severe restrictions on the computational resources
(such as memory or computational power) available to microcontroller devices.
This paper addresses model based synthesis of control software by trading
system level non-functional requirements (such us optimal set-up time, ripple)
with software non-functional requirements (its footprint). Our experimental
results show the effectiveness of our approach: for the inverted pendulum
benchmark, by using a quantization schema with 12 bits, the size of the small
controller is less than 6% of the size of the time optimal one.Comment: Accepted for publication by EMSOFT 2012. arXiv admin note:
substantial text overlap with arXiv:1107.5638,arXiv:1207.409
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