3,042 research outputs found
How many laypeople holding a popular opinion are needed to counter an expert opinion?
In everyday situations, people regularly receive information from large groups of (lay) people and from single experts. Although lay opinions and expert opinions have been studied extensively in isolation, the present study examined the relationship between the two by asking how many laypeople are needed to counter an expert opinion. A Bayesian formalisation allowed the prescription of this quantity. Participants were subsequently asked to assess how many laypeople are needed in different situations. The results demonstrate that people are sensitive to the relevant factors identified for determining how many lay opinions are required to counteract a single expert opinion. People's assessments were fairly good in line with Bayesian predictions
Meta-level argumentation framework for representing and reasoning about disagreement
The contribution of this thesis is to the field of Artificial Intelligence (AI), specifically
to the sub-field called knowledge engineering. Knowledge engineering involves the
computer representation and use of the knowledge and opinions of human experts.In real world controversies, disagreements can be treated as opportunities for
exploring the beliefs and reasoning of experts via a process called argumentation.
The central claim of this thesis is that a formal computer-based framework for
argumentation is a useful solution to the problem of representing and reasoning with
multiple conflicting viewpoints.The problem which this thesis addresses is how to represent arguments in domains in
which there is controversy and disagreement between many relevant points of view.
The reason that this is a problem is that most knowledge based systems are founded in
logics, such as first order predicate logic, in which inconsistencies must be eliminated
from a
theory in order for meaningful inference to be possible from it.I argue that it is possible to devise an argumentation framework by describing one
(FORA : Framework for Opposition and Reasoning about Arguments). FORA
contains a language for representing the views of multiple experts who disagree or
have differing opinions. FORA also contains a suite of software tools which can
facilitate debate, exploration of multiple viewpoints, and construction and revision of
knowledge bases which are challenged by opposing opinions or evidence.A fundamental part of this thesis is the claim that arguments are meta-level structures
which describe the relationships between statements contained in knowledge bases. It
is important to make a clear distinction between representations in knowledge bases
(the object-level) and representations of the arguments implicit in knowledge bases
(the meta-level). FORA has been developed to make this distinction clear and its main
benefit is that the argument representations are independent of the object-level
representation language. This is useful because it facilitates integration of arguments
from multiple sources using different representation languages, and because it enables
knowledge engineering decisions to be made about how to structure arguments and
chains of reasoning, independently of object-level representation decisions.I argue that abstract argument representations are useful because they can facilitate a
variety of knowledge engineering tasks. These include knowledge acquisition;
automatic abstraction from existing formal knowledge bases; and construction, rerepresentation,
evaluation and criticism of object-level knowledge bases. Examples
of software tools contained within FORA are used to illustrate these uses of
argumentation structures. The utility of a meta-level framework for argumentation,
and FORA in particular, is demonstrated in terms of an important real world
controversy concerning the health risks of a group of toxic compounds called
aflatoxins
Collaboration in the Semantic Grid: a Basis for e-Learning
The CoAKTinG project aims to advance the state of the art in collaborative mediated spaces for the Semantic Grid. This paper presents an overview of the hypertext and knowledge based tools which have been deployed to augment existing collaborative environments, and the ontology which is used to exchange structure, promote enhanced process tracking, and aid navigation of resources before, after, and while a collaboration occurs. While the primary focus of the project has been supporting e-Science, this paper also explores the similarities and application of CoAKTinG technologies as part of a human-centred design approach to e-Learning
A Labelling Framework for Probabilistic Argumentation
The combination of argumentation and probability paves the way to new
accounts of qualitative and quantitative uncertainty, thereby offering new
theoretical and applicative opportunities. Due to a variety of interests,
probabilistic argumentation is approached in the literature with different
frameworks, pertaining to structured and abstract argumentation, and with
respect to diverse types of uncertainty, in particular the uncertainty on the
credibility of the premises, the uncertainty about which arguments to consider,
and the uncertainty on the acceptance status of arguments or statements.
Towards a general framework for probabilistic argumentation, we investigate a
labelling-oriented framework encompassing a basic setting for rule-based
argumentation and its (semi-) abstract account, along with diverse types of
uncertainty. Our framework provides a systematic treatment of various kinds of
uncertainty and of their relationships and allows us to back or question
assertions from the literature
Designing Normative Theories for Ethical and Legal Reasoning: LogiKEy Framework, Methodology, and Tool Support
A framework and methodology---termed LogiKEy---for the design and engineering
of ethical reasoners, normative theories and deontic logics is presented. The
overall motivation is the development of suitable means for the control and
governance of intelligent autonomous systems. LogiKEy's unifying formal
framework is based on semantical embeddings of deontic logics, logic
combinations and ethico-legal domain theories in expressive classic
higher-order logic (HOL). This meta-logical approach enables the provision of
powerful tool support in LogiKEy: off-the-shelf theorem provers and model
finders for HOL are assisting the LogiKEy designer of ethical intelligent
agents to flexibly experiment with underlying logics and their combinations,
with ethico-legal domain theories, and with concrete examples---all at the same
time. Continuous improvements of these off-the-shelf provers, without further
ado, leverage the reasoning performance in LogiKEy. Case studies, in which the
LogiKEy framework and methodology has been applied and tested, give evidence
that HOL's undecidability often does not hinder efficient experimentation.Comment: 50 pages; 10 figure
ProCLAIM: an argument-based model for deliberating over safety critical actions
In this Thesis we present an argument-based model – ProCLAIM – intended to provide a setting for heterogeneous agents to deliberate on whether a proposed action is safe. That is, whether or not a proposed action is expected to cause some undesirable side effect that
will justify not to undertake the proposed action. This is particularly relevant in safetycritical environments where the consequences ensuing from an inappropriate action may be catastrophic.
For the practical realisation of the deliberations the model features a mediator agent with three main tasks: 1) guide the participating agents in what their valid argumentation moves are at each stage of the deliberation; 2) decide whether submitted arguments should be accepted on the basis of their relevance; and finally, 3) evaluate the accepted arguments in order to provide an assessment on whether the proposed action should or should not be undertaken, where the argument evaluation is based on domain consented knowledge (e.g guidelines and regulations), evidence and the decision makers’ expertise.
To motivate ProCLAIM’s practical value and generality the model is applied in two scenarios: human organ transplantation and industrial wastewater. In the former scenario, ProCLAIM is used to facilitate the deliberation between two medical doctors on whether an available organ for transplantation is or is not suitable for a particular potential recipient (i.e. whether it is safe to transplant the organ). In the later scenario, a number of agents deliberate on whether an industrial discharge is environmentally safe.En esta tesis se presenta un modelo basado en la Argumentación –ProCLAIM– cuyo n es proporcionar un entorno para la deliberación sobre acciones críticas para la seguridad entre agentes heterogéneos. En particular, el propósito de la deliberación es decidir si los efectos secundario indeseables de una acción justi can no llevarla a cabo. Esto es particularmente relevante en entornos críticos para la seguridad, donde las consecuencias que se derivan de una acción inadecuada puede ser catastró cas.
Para la realización práctica de las deliberaciones propuestas, el modelo cuenta con un agente mediador con tres tareas principales: 1) guiar a los agentes participantes indicando cuales son las líneas argumentación válidas en cada etapa de la deliberación; 2) decidir si los argumentos presentados deben ser aceptadas sobre la base de su relevancia y, por último, 3) evaluar los argumentos aceptados con el n de proporcionar una valoración sobre la seguridad de la acción propuesta. Esta valoración se basa en guías y regulaciones del dominio de aplicación, en evidencia y en la opinión de los expertos responsables de la decisión.
Para motivar el valor práctico y la generalidad de ProCLAIM, este modelo se aplica en dos escenarios distintos: el trasplante de órganos y la gestión de aguas residuales. En el primer escenario el modelo se utiliza para facilitar la deliberación entre dos médicos sobre la viabilidad del transplante de un órgano para un receptor potencial (es decir, si el transplante es seguro). En el segundo escenario varios agentes deliberan sobre si los efectos de un vertido industrial con el propósito de minimizar su impacto medioambiental
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