28,572 research outputs found
Using Taint Analysis and Reinforcement Learning (TARL) to Repair Autonomous Robot Software
It is important to be able to establish formal performance bounds for
autonomous systems. However, formal verification techniques require a model of
the environment in which the system operates; a challenge for autonomous
systems, especially those expected to operate over longer timescales. This
paper describes work in progress to automate the monitor and repair of
ROS-based autonomous robot software written for an a-priori partially known and
possibly incorrect environment model. A taint analysis method is used to
automatically extract the data-flow sequence from input topic to publish topic,
and instrument that code. A unique reinforcement learning approximation of MDP
utility is calculated, an empirical and non-invasive characterization of the
inherent objectives of the software designers. By comparing off-line (a-priori)
utility with on-line (deployed system) utility, we show, using a small but real
ROS example, that it's possible to monitor a performance criterion and relate
violations of the criterion to parts of the software. The software is then
patched using automated software repair techniques and evaluated against the
original off-line utility.Comment: IEEE Workshop on Assured IEEE Workshop on Assured Autonomous Systems,
May, 202
Maximum stabilizer dimension for nonproduct states
Composite quantum states can be classified by how they behave under local
unitary transformations. Each quantum state has a stabilizer subgroup and a
corresponding Lie algebra, the structure of which is a local unitary invariant.
In this paper, we study the structure of the stabilizer subalgebra for n-qubit
pure states, and find its maximum dimension to be n-1 for nonproduct states of
three qubits and higher. The n-qubit Greenberger-Horne-Zeilinger state has a
stabilizer subalgebra that achieves the maximum possible dimension for pure
nonproduct states. The converse, however, is not true: we show examples of pure
4-qubit states that achieve the maximum nonproduct stabilizer dimension, but
have stabilizer subalgebra structures different from that of the n-qubit GHZ
state.Comment: 6 page
On the rough Gronwall lemma and its applications
We present a rough path analog of the classical Gronwall Lemma introduced
recently by A. Deya, M. Gubinelli, M. Hofmanov\'a, S. Tindel in
[arXiv:1604.00437] and discuss two of its applications. First, it is applied in
the framework of rough path driven PDEs in order to establish energy estimates
for weak solutions. Second, it is used in order to prove uniqueness for
reflected rough differential equations
A Remote Sensing Evaluation of Forest Resources in Indiana's Coastal Zone Management Area
No abstract availabl
Lightweight Multilingual Software Analysis
Developer preferences, language capabilities and the persistence of older
languages contribute to the trend that large software codebases are often
multilingual, that is, written in more than one computer language. While
developers can leverage monolingual software development tools to build
software components, companies are faced with the problem of managing the
resultant large, multilingual codebases to address issues with security,
efficiency, and quality metrics. The key challenge is to address the opaque
nature of the language interoperability interface: one language calling
procedures in a second (which may call a third, or even back to the first),
resulting in a potentially tangled, inefficient and insecure codebase. An
architecture is proposed for lightweight static analysis of large multilingual
codebases: the MLSA architecture. Its modular and table-oriented structure
addresses the open-ended nature of multiple languages and language
interoperability APIs. We focus here as an application on the construction of
call-graphs that capture both inter-language and intra-language calls. The
algorithms for extracting multilingual call-graphs from codebases are
presented, and several examples of multilingual software engineering analysis
are discussed. The state of the implementation and testing of MLSA is
presented, and the implications for future work are discussed.Comment: 15 page
Velocity profiles in laminar diffusion flames
Velocity profiles in vertical laminar diffusion flames were measured by using laser Doppler velocimetry (LDV). Four fuels were used: n-heptane, iso-octane, cyclohexane, and ethyl alcohol. The velocity profiles were similar for all the fuels, although there were some differences in the peak velocities. The data compared favorably with the theoretical velocity predictions. The differences could be attributed to errors in experimental positioning and in the prediction of temperature profiles. Error in the predicted temperature profiles are probably due to the difficulty in predicting the radiative heat losses from the flame
Lightweight Call-Graph Construction for Multilingual Software Analysis
Analysis of multilingual codebases is a topic of increasing importance. In
prior work, we have proposed the MLSA (MultiLingual Software Analysis)
architecture, an approach to the lightweight analysis of multilingual
codebases, and have shown how it can be used to address the challenge of
constructing a single call graph from multilingual software with mutual calls.
This paper addresses the challenge of constructing monolingual call graphs in a
lightweight manner (consistent with the objective of MLSA) which nonetheless
yields sufficient information for resolving language interoperability calls. A
novel approach is proposed which leverages information from a
compiler-generated AST to provide the quality of call graph necessary, while
the program itself is written using an Island Grammar that parses the AST
providing the lightweight aspect necessary. Performance results are presented
for a C/C++ implementation of the approach, PAIGE (Parsing AST using Island
Grammar Call Graph Emitter) showing that despite its lightweight nature, it
outperforms Doxgen, is robust to changes in the (Clang) AST, and is not
restricted to C/C++.Comment: 10 page
Propagation of Errors for Matrix Inversion
A formula is given for the propagation of errors during matrix inversion. An
explicit calculation for a 2 by 2 matrix using both the formula and a Monte
Carlo calculation are compared. A prescription is given to determine when a
matrix with uncertain elements is sufficiently nonsingular for the calculation
of the covariances of the inverted matrix elements to be reliable.Comment: 18 pages, 4 figures, figure 4 contains two eps file
Werner state structure and entanglement classification
We present applications of the representation theory of Lie groups to the
analysis of structure and local unitary classification of Werner states,
sometimes called the {\em decoherence-free} states, which are states of
quantum bits left unchanged by local transformations that are the same on each
particle. We introduce a multiqubit generalization of the singlet state, and a
construction that assembles these into Werner states.Comment: 9 pages, 2 figures, minor changes and corrections for version
Minimum orbit dimension for local unitary action on n-qubit pure states
The group of local unitary transformations partitions the space of n-qubit
quantum states into orbits, each of which is a differentiable manifold of some
dimension. We prove that all orbits of the n-qubit quantum state space have
dimension greater than or equal to 3n/2 for n even and greater than or equal to
(3n + 1)/2 for n odd. This lower bound on orbit dimension is sharp, since
n-qubit states composed of products of singlets achieve these lowest orbit
dimensions.Comment: 19 page
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