Belief systems for persuasive discourse planning

This thesis is concerned with the problem of construction of the logical structure of a persuasive discourse. A persuasive discourse can be defined as a monodirectional form of communication, generated by a speaker in order to convince a hearer about the validity (or fallacy) of a specific belief The construction of the structure of a persuasive discourse is realized, in this work, through the adoption of two basic elements: a belief system and a planning system. The planning system is used as a tool for the automatic generation of the discourse structure (or plan), obtained through the decomposition of the assigned (communicative) goals of persuasion, aimed at producing specific effects on the hearer’s beliefs. The belief system is adopted in order to endow the planning process with a formal language of beliefs for the representation of such goals, and with the mechanisms which govern the propagation of their (expected) effects on the rest of the hearer's belief state. The main results presented consist of the formalization of a paradigm for specification of belief systems, and of a method — whose correctness is formally proved — for their integration with planning systems. The formalization of a belief system for discourse structure representation (defined in accordance with the theoretical paradigm) is also given, together with the description of its implementation and integration with a specific planner, which resulted in the actual completion of a system for the automatic generation of persuasive discourse plans

Aberrant methylation patterns in colorectal cancer: A meta-analysis

Colorectal cancer is among the leading causes of cancer death worldwide. Despite numerous molecular characterizations of the phenomenon, the exact dynamics of its onset and progression remain elusive. Colorectal cancer onset has been characterized by changes in DNA methylation profiles, that, owing to the stability of their patterns, are promising candidates to shed light on the molecular events laying at the base of this phenomenon. To exploit this stability and reinforce it, we conducted a meta-analysis on publicly available DNA methylation datasets generated on: normal colorectal, adenoma (ADE) and adenocarcinoma (CRC) samples using the Illumina 450k array, in the systems medicine frame, searching for tumor gene episignatures, to produce a carefully selected list of potential drivers, markers and targets of the disease. The analysis proceeds from a differential meta-analysis of the methylation profiles using an analytical pipeline recently developed by our group [1], through network reconstruction, topological and functional analyses, to finally highlight relevant epigenomic features. Our results show that genes already highlighted for their genetic or transcriptional alteration in colorectal cancer are also differentially methylated, reinforcing -regardless of the level of cellular control- their role in the complex of alterations involved in tumorigenesis. These findings were finally validated in an independent cohort from The Cancer Genome Atlas (TCGA)

Belief Systems and Plans for Communication

Communication between rational agents can be seen as an exchange of internal concepts expressed using a shared language. Most of the communication acts between humans are performed through Natural Language (NL), and the meaning of the expressions of the language adopted is assumed to be known and properly understood by all of the participants. This suggests that the process of communication using NL requires the source-agent (‘speaker’) to hypothesise a model of its audience’s (‘hearer’) knowledge and beliefs. Moreover, the initial reasons which originate the intention (or need) to communicate (and which may or may not be included in the message) might consist of more abstract perlocutionary goals, such as the induction of a specific reasoning process (inference) within the hearer’s mind producing the change of one or more of his/her beliefs. Since these goals play an important role in the process of determining the content and the structure of a discourse, it becomes necessary for the speaker not only to hypothesise and maintain a model of the hearer’s beliefs, but also to plan the structure of the message according to the effects that the utterances will have upon them. Whilst research in modal logics has produced many theoretical results on the subject of belief systems

To my Grandfather Acknowledgments

When, back in 1994, I first saw, on the departmental board of the University of Bologna, the notice publicizing the research which was being carried out at Durham, I had no idea whatsoever of what the acronym "Ph.D. " meant. Five years have passed since, and many people have helped me through this long path. With these thanks I intend to reach them all, even those who, for reasons of space, could not be mentioned here. First of all, I wish to express my gratitude to my partner Grazia and my family, who have been constant and unreplaceable sources of support and encouragement. My most special thanks go also to Maria and Derek, who have guided me through the arduous paths of the research with intuition, enthusiasm and competence. Secondly, I am grateful to all of my school and university teachers, whose effort has contributed towards my education as a student, researcher and individual. In particular, I would like to thank Prof. Donatiello, for his encouragement and support, and Prof. Zaccarini, for her enjoyable classes and for dedicating me one of her poems

Belief Systems for Conflict Resolution

. In a multiagent system, conflicts may arise because of two basic reasons: 1) different agents have contrasting goals; 2) different agents have inconsistent knowledge. This situation can originate when agents are autonomous and strongly motivated by their own interests, and when heterogeneous agents, with different skills, `histories' and beliefs, coexist in a dynamic environment. This paper is focused on the representation of two agents' epistemic conflicts, originated by the presence of contrasting beliefs. In such a situation, for an agent `S' to agree on a cooperative plan with another agent `H' it is necessary to communicate and solve the conflicts which could prevent the realisation of the specific plan identified. In order to do this, S must be able to reason about H's beliefs and goals. This requires S to maintain an adequate representation of H's mental states and to use this model to develop a plan for communication which will persuade H to adopt the cooperati..