A Gentle Introduction to Epistemic Planning: The DEL Approach

Epistemic planning can be used for decision making in multi-agent situations with distributed knowledge and capabilities. Dynamic Epistemic Logic (DEL) has been shown to provide a very natural and expressive framework for epistemic planning. In this paper, we aim to give an accessible introduction to DEL-based epistemic planning. The paper starts with the most classical framework for planning, STRIPS, and then moves towards epistemic planning in a number of smaller steps, where each step is motivated by the need to be able to model more complex planning scenarios.Comment: In Proceedings M4M9 2017, arXiv:1703.0173

Learning Action Models: Qualitative Approach

In dynamic epistemic logic, actions are described using action models. In this paper we introduce a framework for studying learnability of action models from observations. We present first results concerning propositional action models. First we check two basic learnability criteria: finite identifiability (conclusively inferring the appropriate action model in finite time) and identifiability in the limit (inconclusive convergence to the right action model). We show that deterministic actions are finitely identifiable, while non-deterministic actions require more learning power-they are identifiable in the limit. We then move on to a particular learning method, which proceeds via restriction of a space of events within a learning-specific action model. This way of learning closely resembles the well-known update method from dynamic epistemic logic. We introduce several different learning methods suited for finite identifiability of particular types of deterministic actions.Comment: 18 pages, accepted for LORI-V: The Fifth International Conference on Logic, Rationality and Interaction, October 28-31, 2015, National Taiwan University, Taipei, Taiwa

Three-Dimensional Network Model for Coupling~of~Fracture and Mass Transport in Quasi-Brittle Geomaterials

Dual three-dimensional networks of structural and transport elements were combined to model the effect of fracture on mass transport in quasi-brittle geomaterials. Element connectivity of the structural network, representing elasticity and fracture, was defined by the Delaunay tessellation of a random set of points. The connectivity of transport elements within the transport network was defined by the Voronoi tessellation of the same set of points. A new discretisation strategy for domain boundaries was developed to apply boundary conditions for the coupled analyses. The properties of transport elements were chosen to evolve with the crack opening values of neighbouring structural elements. Through benchmark comparisons involving non-stationary transport and fracture, the proposed dual network approach was shown to be objective with respect to element size and orientation

Cooperative Epistemic Multi-Agent Planning for Implicit Coordination

Epistemic planning can be used for decision making in multi-agent situations with distributed knowledge and capabilities. Recently, Dynamic Epistemic Logic (DEL) has been shown to provide a very natural and expressive framework for epistemic planning. We extend the DEL-based epistemic planning framework to include perspective shifts, allowing us to define new notions of sequential and conditional planning with implicit coordination. With these, it is possible to solve planning tasks with joint goals in a decentralized manner without the agents having to negotiate about and commit to a joint policy at plan time. First we define the central planning notions and sketch the implementation of a planning system built on those notions. Afterwards we provide some case studies in order to evaluate the planner empirically and to show that the concept is useful for multi-agent systems in practice.Comment: In Proceedings M4M9 2017, arXiv:1703.0173

Seeing is Believing: Formalising False-Belief Tasks in Dynamic Epistemic Logic

Abstract. In this paper we show how to formalise false-belief tasks like the Sally-Anne task and the second-order chocolate task in Dynamic Epistemic Logic (DEL). False-belief tasks are used to test the strength of the Theory of Mind (ToM) of humans, that is, a human’s ability to attribute mental states to other agents. Having a ToM is known to be essential to human social intelligence, and hence likely to be essential to social intelligence of artificial agents as well. It is therefore important to find ways of implementing a ToM in artificial agents, and to show that such agents can then solve false-belief tasks. In this paper, the approach is to use DEL as a formal framework for representing ToM, and use reasoning in DEL to solve false-belief tasks. In addition to formalising several false-belief tasks in DEL, the paper introduces some extensions of DEL itself: edge-conditioned event models and observability propositions. These extensions are introduced to provide better formalisations of the false-belief tasks, but expected to have independent future interest.

On the relevance of Bernstein for German-speaking Switzerland

This article assesses the relevance of Basil Bernstein for German-speaking Switzerland. It argues that Bernstein is potentially relevant for German-speaking Switzerland in light of contemporary studies which highlight a connection between social background and differential school achievement. After contextualising Bernstein's theoretical outlook and critically reflecting upon his use of a static concept of social class, it explores past and present applications of Bernstein. The paper thereby shows that the uptake of Bernstein's outlook was and continues to be minimal for the Swiss German context and reasons for this conclusion are explored. In the final sections of the article connections between social background and differential school achievement are explored for contemporary German-speaking Switzerland. On the basis of this analysis, the paper concludes by arguing that while aspects of Basil Bernstein's theoretical outlook are potentially relevant for the Swiss German context, they need to be reassessed in light of the awareness of the variety of interdependent factors which can and do influence the performance of children and adolescents at schoo

A multi-species analysis of biomechanical responses of the head to a shock wave

Shock wave induced brain injury remains a field of research that has great consequences for the rehabilitation of soldiers and civilians that are exposed to an explosion. As such, for the research to be successful in developing strategies to mitigate the effects of these injuries, appropriate research methods need to be developed. Animal models are currently employed to understand the brain\u27s response to a shock wave exposure. Unfortunately no criteria have been established that indicates in what way the mechanical inputs that the cells in an animal\u27s brain are subjected to are similar to a human. The purpose of this dissertation was to investigate these biomechanical responses. To address this question, the biomechanical responses of the rat, pig, and post mortem human subject were analyzed. Each of the species was exposed to multiple shock waves within a shock tube. Skull strain was measured using strain gages and intracranial pressure was measured using fiber optic pressure sensors. The effect of orientation was also addressed for the cadaver and the porcine. The results of the project indicate that for all three species, as the incident shock wave amplitude increases, the peak strain and ICP also increases. Also, the response of the head is unique to orientation. A front facing head will respond differently than a side facing head. The relationships between skull strain and ICP were also demonstrated. Skull flexure has a dominate effect on the ICP response. Additionally key characteristic waveforms describing the skull surface and ICP wave dynamics were identified. Overall this project provides much needed information in the field of blast biomechanics. The results of the study indicate that each species will experience pressure wave profiles in the brain partially by means of skull flexure. And that the intracranial pressure environment is dependent on intensity, orientation of the head, and species being tested. It is possible that the responses of each species can be simplified into relative contributions of the identified waveforms. This research provides a basis for further studies that will either investigate methods for mitigating the effects of shock wave exposure or investigating brain cell response to pressure waveforms that are generated within the brain when exposed to a shock wave

Alice\u27s Adventures in Wonderland Puzzle Book

A collection of puzzles corresponding to Alice in Wonderland