Model checking learning agent systems using Promela with embedded C code and abstraction

As autonomous systems become more prevalent, methods for their verification will become more widely used. Model checking is a formal verification technique that can help ensure the safety of autonomous systems, but in most cases it cannot be applied by novices, or in its straight \off-the-shelf" form. In order to be more widely applicable it is crucial that more sophisticated techniques are used, and are presented in a way that is reproducible by engineers and verifiers alike. In this paper we demonstrate in detail two techniques that are used to increase the power of model checking using the model checker SPIN. The first of these is the use of embedded C code within Promela specifications, in order to accurately re ect robot movement. The second is to use abstraction together with a simulation relation to allow us to verify multiple environments simultaneously. We apply these techniques to a fairly simple system in which a robot moves about a fixed circular environment and learns to avoid obstacles. The learning algorithm is inspired by the way that insects learn to avoid obstacles in response to pain signals received from their antennae. Crucially, we prove that our abstraction is sound for our example system { a step that is often omitted but is vital if formal verification is to be widely accepted as a useful and meaningful approach

GraphDraw—A Tool for the Represention of Graphs Using Inherent Symmetry

No abstract available

Whose impartiality? An experimental study of veiled stakeholders, impartial spectators and ideal observers

This article defines in a precise manner three different mechanisms to achieve impartiality in distributive justice and studies them experimentally. We consider a first-person procedure, the Rawlsian veil of ignorance, and two third-party procedures, the impartial spectator and the ideal observer. As a result, we find striking differences in the chosen outcome distributions by the three methods. Ideal observers that do not have a stake in the allocation problem nor information about their position in society propose significantly more egalitarian distributions than veiled stakeholders or impartial spectators. Risk preferences seem to explain why participants that have a stake in the final allocation propose less egalitarian distributions. Impartial spectators that are informed about their position in society tend to favor stakeholders holding the same position.impartiality, veil of ignorance, impartial spectator, distributive justice

Solving Graph Coloring Problems with Abstraction and Symmetry

This paper introduces a general methodology, based on abstraction and symmetry, that applies to solve hard graph edge-coloring problems and demonstrates its use to provide further evidence that the Ramsey number $R(4,3,3)=30$. The number $R(4,3,3)$ is often presented as the unknown Ramsey number with the best chances of being found "soon". Yet, its precise value has remained unknown for more than 50 years. We illustrate our approach by showing that: (1) there are precisely 78{,}892 $(3,3,3;13)$ Ramsey colorings; and (2) if there exists a $(4,3,3;30)$ Ramsey coloring then it is (13,8,8) regular. Specifically each node has 13 edges in the first color, 8 in the second, and 8 in the third. We conjecture that these two results will help provide a proof that no $(4,3,3;30)$ Ramsey coloring exists implying that $R(4,3,3)=30$

Hu Jintao’s “Concession” on Human Rights

Chinese President and CCP General Secretary Hu Jintao’s remarks on human rights during his joint press conference with President Obama in Washington on 19 January have been widely regarded in foreign media as a grudging concession that broke new ground in Beijing’s position on the issue. Specifically, confronted by a persistent Washington press corps, Hu for the first time acknowledged “the universality of human rights” in international politics and conceded that “a lot still needs to be done in China in terms of human rights.

Timed Fault Tree Models of the China Yongwen Railway Accident

Safety is an essential requirement for railway transportation. There are many methods that have been developed to predict, prevent and mitigate accidents in this context. All of these methods have their own purpose and limitations. This paper presents a new useful analysis technique: timed fault tree analysis. This method extends traditional fault tree analysis with temporal events and fault characteristics. Timed Fault Trees (TFTs) can determine which faults need to be eliminated urgently, and it can also provide a safe time window to repair them. They can also be used to determine the time taken for railway maintenance requirements, and thereby improve maintenance efficiency, and reduce risks. In this paper, we present the features and functionality of a railway transportation system based on timed fault tree models. We demonstrate the applicability of our framework via a case study of the China Yongwen line railway accident