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

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

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

A Remote Sensing Evaluation of Forest Resources in Indiana's Coastal Zone Management Area

No abstract availabl

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

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 $n$ 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

High-Precision Entropy Values for Spanning Trees in Lattices

Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the accuracy. In particular, the new values resolve one of their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed slightly. 2nd revision corrects first displayed equatio

Determination of combustion gas temperatures by infrared radiometry in sooting and nonsooting flames

Flame temperatures in nonsooting and sooting environments were successfully measured by radiometry for pre-mixed propane-oxygen laminar flames stabilized on a water-cooled, porous sintered-bronze burner. The measured temperatures in the nonsooting flames were compared with fine-wire thermocouple measurements. The results show excellent agreement below 1700 K, and when the thermocouple measurements were corrected for radiation effects, the agreement was good for even higher temperatures. The benefits of radiometry are: (1) the flow is not disturbed by an intruding probe, (2) calibration is easily done using a blackbody source, and (3) measurements can be made even with soot present. The theory involved in the radiometry measurements and the energy balance calculations used to correct the thermocouple temperature measurements are discussed