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Martin Loetzsch

Assistant Researcher - PhD Student

language

2012

Open-ended Procedural Semantics

Topics:
Language
Authors
Michael Spranger , Simon Pauw , Martin Loetzsch , Luc Steels |

Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, New York, 2012. pp.153--172.

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Abstract

This chapter introduces the computational infrastructure that is used to bridge the gap between results from sensorimotor processing and language. It consists of a system called Incremental Recruitment Language (IRL) that is able to configure a network of cognitive operations to achieve a particular communicative goal. IRL contains mechanisms for finding such networks, chunking subnetworks for more efficient later reuse, and completing partial networks (as possibly derived from incomplete or only partially understood sentences).

2012

A Perceptual System for Language Game Experiments

Topics:
Language
Authors
Michael Spranger , Martin Loetzsch , Luc Steels |

Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, 2012. pp.89--110.

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Abstract

This chapter describes key aspects of a visual perception system as a key component for language game experiments on physical robots. The vision system is responsible for segmenting the continuous flow of incoming visual stimuli into segments and computing a variety of features for each segment. This happens by a combination of bottom-up way processing that work on the incoming signal and top-down processing based on expectations about what was seen before or objects stored in memory. This chapter consists of two parts. The first one is concerned with extracting and maintaining world models about spatial scenes, without any prior knowledge of the possible objects involved. The second part deals with the recognition of gestures and actions which establish the joint attention and pragmatic feedback that is an important aspect of language games.

2012

The Grounded Naming Game

Topics:
Language
Authors
Luc Steels , Martin Loetzsch |

Experiments in Cultural Language Evolution, edited by:Steels, Luc, John Benjamins, Amsterdam, 2012. pp.41--59.

2011

Syntactic indeterminacy and semantic ambiguity – A case study for German spatial phrases

Topics:
Language
Authors
Michael Spranger , Martin Loetzsch |

Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011. pp.265--298.

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Abstract

This chapter presents an operational grammar for German spatial language, in particular German locative phrases, as a case study for processing distributed information. It investigates the complex interplay of syntactic phenomena and spatial semantics, with a specific emphasis on efficient processing of syntactic indeterminacy and semantic ambiguity. Since FCG applies constructions in a sequence one after the other, the main challenge lies in mutual dependencies between constructions, that is, some constructions require pieces of information in order to make decisions that are only later on provided by other constructions. We present solutions and design patterns for dealing with these processing issues, which all have in common the strategy of postponing decisions as long as possible in processing until all the necessary information for making the decision is available.

2010

Open-ended semantics co-evolving with spatial language

Topics:
Language
Authors
Michael Spranger , Simon Pauw , Martin Loetzsch |

The Evolution of Language (EVOLANG 8), edited by:Smith, A.D.M. and Schouwstra, M. and de Boer, B. and Smith, K., World Scientific, Singapore, 2010. pp.297--304.

2010

Open-ended Grounded Semantics

Topics:
Language
Authors
Michael Spranger , Martin Loetzsch , Simon Pauw |

Proceedings of the 19th European Conference on Artificial Intelligence (ECAI 2010), edited by:Coelho, H. and Studer, R. and Woolridge, M., IOS Press, 2010. pp.929--934.

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Abstract

Artificial agents trying to achieve communicative goals in situated interactions in the real-world need powerful computational systems for conceptualizing their environment. In order to provide embodied artificial systems with rich semantics reminiscent of human language complexity, agents need ways of both conceptualizing complex compositional semantic structure and actively reconstructing semantic structure, due to uncertainty and ambiguity in transmission. Furthermore, the systems must be open-ended and adaptive and allow agents to adjust their semantic inventories in order to reach their goals. This paper presents recent progress in modeling open-ended, grounded semantics through a unified software system that addresses these problems.

2010

Why robots?

Topics:
Language
Authors
Martin Loetzsch , Michael Spranger |

The Evolution of Language (EVOLANG 8), edited by:Smith, A.D.M. and Schouwstra, M. and de Boer, B. and Smith, K., World Scientific, Singapore, 2010. pp.222--229.

2010

Babel: A Tool for Running Experiments on the Evolution of Language

Topics:
Language
Authors
Luc Steels , Martin Loetzsch |

Evolution of Communication and Language in Embodied Agents, edited by:Nolfi, S. and Mirolli, M., Springer, Berlin, 2010. pp.307--313.

2009

The Semantics of SIT, STAND, and LIE Embodied in Robots

Topics:
Language
Authors
Michael Spranger , Martin Loetzsch |

Proceedings of the 31th Annual Conference of the Cognitive Science Society (Cogsci09), edited by:Taatgen, N.A. and van Rijn, H., Cognitive Science Society, Austin, TX, 2009. pp.2546-2552.

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Abstract

In this paper we demonstrate (1) how a group of embodied artificial agents can learn to construct abstract conceptual representations of body postures from their continuous sensorimotor interaction with the environment, (2) how they can metaphorically extend these bodily concepts to visual experiences of external objects and (3) how they can use their acquired embodied meanings for self-organizing a communication system about postures and objects. For this, we endow the agents with cognitive mechanisms and structures that are instantiations of specific ideas in cognitive linguistics (namely image schema theory) about how humans relate motor and visual space. We show that the agents are indeed able to perform well in the task and thus the experiment offers a concrete operationalization of these theories and increases their explanatory power.

2009

The Grounded Color Naming Game

Topics:
Language
Authors
Joris Bleys , Martin Loetzsch , Michael Spranger , Luc Steels |

Proceedings of the 18th IEEE International Symposium on Robot and Human Interactive Communication (Ro-man 2009), 2009.

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Abstract

Colour naming games are idealised communicative interactions within a population of artificial agents in which a speaker uses a single colour term to draw the attention of a hearer to a particular object in a shared context. Through a series of such games, a colour lexicon can be developed that is sufficiently shared to allow for successful communication, even when the agents start out without any predefined categories. In previous models of colour naming games, the shared context was typically artificially generated from a set of colour stimuli and both agents in the interaction perceive this environment in an identical way. In this paper, we investigate the dynamics of the colour naming game in a robotic setup in which humanoid robots perceive a set of colourful objects from their own perspective. We compare the resulting colour ontologies to those found in human languages and show how these ontologies reflect the environment in which they were developed.

2008

Perspective Alignment in Spatial Language

Topics:
Language
Authors
Luc Steels , Martin Loetzsch |

Spatial Language and Dialogue, edited by:Coventry, K.R., Tenbrink, T. and Bateman, J.A., Oxford University Press, Oxford, 2008.

2008

Typological and Computational Investigations of Spatial Perspective

Topics:
Language
Authors
Martin Loetzsch , Remi van Trijp , Luc Steels |

Modeling Communication with Robots and Virtual Humans, edited by:Wachsmuth, I. and Knoblich, G., 4930, Springer, Berlin, 2008. pp.125--142.

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Abstract

This paper is part of an ongoing research program to understand the cognitive and functional bases for the origins and evolution of spatial language. Following a cognitive-functional approach, we first investigate the cross-linguistic variety in spatial language, with special attention for spatial perspective. Based on this language-typological data, we hypothesize which cognitive mechanisms are needed to explain this variety and argue for an interdisciplinary approach to test these hypotheses. We then explain how experiments in artificial language evolution can contribute to that and give a concrete example.

2008

Flexible Word Meanings in Embodied Agents

Topics:
Language
Authors
Wellens Pieter , Martin Loetzsch , Luc Steels |

Connection Science, 20, 2-3, 2008. pp.173--191.

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Abstract

Learning the meanings of words requires coping with referential uncertainty ? a learner hearing a novel word cannot be sure which aspects or properties of the referred object or event comprise the meaning of the word. Data from developmental psychology suggest that human learners grasp the important aspects of many novel words after just a few exposures, a phenomenon known as fast mapping. Traditionally, word learning is viewed as a mapping task, in which the learner has to map a set of forms onto a set of pre-existing concepts. We criticise this approach and argue instead for a flexible nature of the coupling between form and meanings as a solution to the problem of referential uncertainty. We implemented and tested the model in populations of humanoid robots that play situated language games about objects in their shared environment. Results show that the model can handle an exponential increase in uncertainty and allows scaling towards very large meaning spaces, while retaining the ability to grasp an operational meaning almost instantly for a great number of words. In addition, the model captures some aspects of the flexibility of form-meaning associations found in human languages. Meanings of words can shift between being very specific (names) and general (e.g. ?small?). We show that this specificity is biased not by the model itself but by the distribution of object properties in the world.

2008

The Babel2 Manual

Topics:
Language
Authors
Martin Loetzsch , Wellens Pieter , De Beule Joachim , Joris Bleys , Remi van Trijp |

AI-Memo 01-08, AI-Lab VUB, Brussels, 2008.