Suna Bensch

Algorithmic properties of millstream systems

Millstream systems have recently been proposed as a formalization of the linguistic idea that natural language should be described as a combination of different modules related by interfaces. In this paper we investigate algorithmic properties of Millstream systems having regular tree grammars as modules and MSO logic as interface logic. We focus on the so-called completion problem: Given trees generated by a subset of the modules, can they be completed into a valid configuration of the Millstream system?

On input-revolving deterministic and nondeterministic finite automata

We introduce and investigate input-revolving finite automata, which are (nondeterministic) finite state automata with the additional ability to shift the remaining part of the input. Three different modes of shifting are considered, namely revolving to the left, revolving to the right, and circular interchanging. We investigate the computational capacities of these three types of automata and their deterministic variants, comparing any of the six classes of automata with each other and with further classes of well-known automata. In particular, it is shown that nondeterminism is better than determinism, that is, for all three modes of shifting there is a language accepted by the nondeterministic model but not accepted by any deterministic automaton of the same type. Concerning the closure properties most of the deterministic language families studied are not closed under standard operations. For example, we show that the family of languages accepted by deterministic right-revolving finite automata is an anti-AFL which is not closed under reversal and intersection.

Input-Driven stack automata

We introduce and investigate input-driven stack automata, which are a generalization of input-driven pushdown automata that recently became popular under the name visibly pushdown automata. Basically, the idea is that the input letters uniquely determine the operations on the pushdown store. This can nicely be generalized to stack automata by further types of input letters which are responsible for moving the stack pointer up or down. While visibly pushdown languages share many desirable properties with regular languages, input-driven stack automata languages do not necessarily so. We prove that deterministic and nondeterministic input-driven stack automata have different computational power, which shows in passing that one cannot construct a deterministic input-driven stack automaton from a nondeterministic one. We study the computational capacity of these devices. Moreover, it is shown that the membership problem for nondeterministic input-driven stack automata languages is NP-complete.

Deterministic Stack Transducers

We introduce and investigate stack transducers, which are one-way stack automata with an output tape. A one-way stack automaton is a classical pushdown automaton with the additional ability to move ...

Graph transformation for incremental natural language analysis

Millstream systems have been proposed as a non-hierarchical method for modelling natural language. Millstream configurations represent and connect multiple structural aspects of sentences. We prese ...

Towards proactive robot behavior based on incremental language analysis

This paper describes ongoing and planned work on incremental language processing coupled to inference of expected robot actions. Utterances are processed word-by-word, simultaneously with inference of expected robot actions, thus enabling the robot to prepare and act proactively to human utterances. We believe that such a model results in more natural human-robot communication since proactive behavior is a feature of human-human communication.

Deterministic Input-Reversal and Input-Revolving Finite Automata

Extended finite automata are finite state machines with the additional ability to manipulate the remaining part of the input. We investigate three types of deterministic extended automata, namely left-revolving, right-revolving, and input reversal finite automata. Concerning their computational capacity it is shown that nondeterminism is better than determinism, that is, for all three types of automata there is a language accepted by the nondeterministic versions but not accepted by any deterministic automaton of the same type. Concerning the closure properties most of the language families studied are not closed under standard operations. In particular, we show that the family of languages accepted by deterministic right-revolving finite automata is an anti-AFL which is not closed under reversal and intersection.

On interaction quality in human-robot interaction

In many complex robotics systems, interaction takes place in all directions between human, robot, and environment. Performance of such a system depends on this interaction, and a proper evaluation ...

Understandable robots - What, Why, and How

Abstract As robots become more and more capable and autonomous, there is an increasing need for humans to understand what the robots do and think. In this paper, we investigate what such understanding means and includes, and how robots can be designed to support understanding. After an in-depth survey of related earlier work, we discuss examples showing that understanding includes not only the intentions of the robot, but also desires, knowledge, beliefs, emotions, perceptions, capabilities, and limitations of the robot. The term understanding is formally defined, and the term communicative actions is defined to denote the various ways in which a robot may support a human’s understanding of the robot. A novel model of interaction for understanding is presented. The model describes how both human and robot may utilize a first or higher-order theory of mind to understand each other and perform communicative actions in order to support the other’s understanding. It also describes simpler cases in which the robot performs static communicative actions in order to support the human’s understanding of the robot. In general, communicative actions performed by the robot aim at reducing the mismatch between the mind of the robot, and the robot’s inferred model of the human’s model of the mind of the robot. Based on the proposed model, a set of questions are formulated, to serve as support when developing and implementing the model in real interacting robots.

Modelling the Formation of Virtual Buying Cooperatives with Grammars of Regulated Rewriting

In this paper we model virtual buying cooperatives (VBC) with grammars of regulated rewriting and show that, if VBC relevant information is distributed over several successive VBC processes and mus ...