Charlotte Gerritsen

Model-Based Reasoning Methods within an Ambient Intelligent Agent Model

Ambient agents react on humans on the basis of their information obtained by sensoring and their knowledge about human functioning. Appropriate types of reactions depend on in how far an ambient agent understands the human. On the one hand, such an understanding requires that the agent has knowledge to a certain depth about the human’s physiological and mental processes in the form of an explicitly represented model of the causal and dynamic relations describing these processes. On the other hand, given such a model representation, the agent needs reasoning methods to derive conclusions from the model and the information available by sensoring. This paper presents a number of such model-based reasoning methods. They have been formally specified in an executable temporal format, which allows for simulation of reasoning traces and automated verification in a dedicated software environment. A number of such simulation experiments and their formal analysis are described.

Comparison of Agent-Based and Population-Based Simulations of Displacement of Crime

Within criminology, the process of crime displacement is usually explained by referring to the interaction of three types of agents: criminals, passers-by, and guardians. Most existing simulation models of this process are agent-based. However, when the number of agents considered becomes large, population-based simulation has computational advantages over agent-based simulation. This paper presents both an agent-based and a population-based simulation model of crime displacement, and reports a comparative evaluation of the two models. In addition, an approach is put forward to analyse the behaviour of both models by means of formal techniques.

Cognitive and social simulation of criminal behaviour: the intermittent explosive disorder case

Criminal behaviour often involves a combination of physical, mental, social and environmental (multi-)agent aspects, such as neurological deviations, hormones, arousal, (non)empathy, targets and social control. This paper contributes a dynamical agent-based approach for analysis and simulation of criminal behaviour, covering the above aspects, illustrated for the case of an Intermittent Explosive Disorder. It involves dynamically generated desires and beliefs in opportunities within the social environment, both based on literature on criminal behaviour.

Agent-based vs. population-based simulation of displacement of crime: A comparative study

Central research questions addressed within Criminology are how the geographical displacement of crime can be understood, explained, and predicted. The process of crime displacement is usually explained by referring to the interaction of three types of agents: criminals, passers-by, and guardians. Most existing simulation models of this process take a ‘local’ perspective, i.e., they are agent-based. However, when the number of agents considered becomes large, more ‘global’ approaches, such as population-based simulation have computational advantages over agent-based simulation. This article presents both an agent-based and a population-based simulation model of crime displacement, and reports a comparative evaluation of the two models. In addition, an approach is put forward to analyse the behaviour of both models by means of formal techniques. The results suggest that under certain conditions, population-based models approximate agent-based models, at least in the domain under investigation.

Towards Integration of Biological, Psychological and Social Aspects in Agent-Based Simulation of Violent Offenders

In the analysis of criminal behavior, a combination of biological, psychological and social aspects may be taken into account. Dynamical modeling methods developed in recent years often address biological, psychological or social dynamical systems separately. This paper makes the first step in the development of an agent-based modeling approach for criminal behavior in which these aspects are integrated in one dynamical system. It is shown how within a certain (multi-agent) social context, biological factors, such as certain brain deviations, testosterone levels and serotonin levels, affect cognitive and emotional functioning in such a way that a crime is committed when the perceived opportunity is there. This paper presents one generic model for the behavior of violent offenders with parameters that can be set to obtain simulation traces for three known types of offenders.

Methods for model-based reasoning within agent-based Ambient Intelligence applications

Within agent-based Ambient Intelligence applications agents react to humans based on information obtained by sensoring and their knowledge about human functioning. Appropriate types of reactions depend on the extent to which an agent understands the human and is able to interpret the available information (which is often incomplete, and hence multi-interpretable) in order to create a more complete internal image of the environment, including humans. Such an understanding requires that the agent has knowledge to a certain depth about the humans physiological and mental processes in the form of an explicitly represented model of the causal and dynamic relations describing these processes. In addition, given such a model representation, the agent needs reasoning methods to derive conclusions from the model and interpret the (partial) information available by sensoring. This paper presents the development of a toolbox that can be used by a modeller to design Ambient Intelligence applications. This toolbox contains a number of model-based reasoning methods and approaches to control such reasoning methods. Formal specifications in an executable temporal format are offered, which allows for simulation of reasoning processes and automated verification of the resulting reasoning traces in a dedicated software environment. A number of such simulation experiments and their formal analysis are described. The main contribution of this paper is that the reasoning methods in the toolbox have the possibility to reason using both quantitative and qualitative aspects in combination with a temporal dimension, and the possibility to perform focused reasoning based upon certain heuristic information.

Combining rational and biological factors in virtual agent decision making

To enhance believability of virtual agents, this paper presents an agent-based modelling approach for decision making, which integrates rational reasoning based on means-end analysis with personal psychological and biological aspects. The agent model developed is a combination of a BDI-model and a utility-based decision model in the context of specific desires and beliefs. The approach is illustrated by addressing the behaviour of violent criminals, thereby creating a model for virtual criminals. Within a number of simulation experiments, the model has been tested in the context of a street robbery scenario. In addition, a user study has been performed, which confirms the fact that the model enhances believability of virtual agents.

Comparing Crime Prevention Strategies by Agent-Based Simulation

Within the field of Criminology, an important challenge is to investigate the spatio-temporal dynamics of crime. Typical questions in this area are how the emergence of criminal hot spots can be predicted and prevented. This paper presents an agent-based simulation approach that is able to address such questions. More specifically, the approach can be used to compare different strategies for guardian movement in terms of their effectiveness. To illustrate the approach, a number of simulation experiments have been performed, and the results are discussed.

On the relation between cognitive and biological modelling of criminal behaviour

This article discusses how a cognitive modelling approach for criminal behaviour can be related to a biological modelling approach. The discussion is illustrated by a case study for the behaviour of three types of violent criminals as known from literature within the area of Criminology. A cognitive model is discussed that can show each of the behaviours of these types of criminals, depending on the characteristics set and inputs in terms of stimuli from the environment. Based on literature in Criminology about motivations and opportunities and their underlying biological factors, it is shown by a formal interpretation mapping how the model can be related to a biological grounding. This formal mapping covers ontology elements for states and dynamic properties for processes, and thus shows how the cognitive model can be biologically grounded.

Integration of Biological, Psychological, and Social Aspects in Agent-Based Simulation of a Violent Psychopath

In the analysis of criminal behaviour, a combination of biological, psychological and social aspects may be taken into account. Dynamical modelling methods developed in recent years often address these aspects separately. This paper contributes an agent-based modelling approach for behaviour of a certain criminal type, the violent psychopath, in which these aspects are integrated in one dynamical system. It is shown how within a certain social context, an interaction between biological factors and cognitive and emotional factors can lead to a crime committed when an opportunity is perceived.