83 research outputs found
Syntactic Reasoning with Conditional Probabilities in Deductive Argumentation
Evidence from studies, such as in science or medicine, often corresponds to conditional probability statements. Furthermore, evidence can conflict, in particular when coming from multiple studies. Whilst it is natural to make sense of such evidence using arguments, there is a lack of a systematic formalism for representing and reasoning with conditional probability statements in computational argumentation. We address this shortcoming by providing a formalization of conditional probabilistic argumentation based on probabilistic conditional logic. We provide a semantics and a collection of comprehensible inference rules that give different insights into evidence. We show how arguments constructed from proofs and attacks between them can be analyzed as arguments graphs using dialectical semantics and via the epistemic approach to probabilistic argumentation. Our approach allows for a transparent and systematic way of handling uncertainty that often arises in evidence
Fuzzy expert systems in civil engineering
Imperial Users onl
Syntactic reasoning with conditional probabilities in deductive argumentation
Evidence from studies, such as in science or medicine, often corresponds to conditional probability statements. Furthermore, evidence can conflict, in particular when coming from multiple studies. Whilst it is natural to make sense of such evidence using arguments, there is a lack of a systematic formalism for representing and reasoning with conditional probability statements in computational argumentation. We address this shortcoming by providing a formalization of conditional probabilistic argumentation based on probabilistic conditional logic. We provide a semantics and a collection of comprehensible inference rules that give different insights into evidence. We show how arguments constructed from proofs and attacks between them can be analyzed as arguments graphs using dialectical semantics and via the epistemic approach to probabilistic argumentation. Our approach allows for a transparent and systematic way of handling uncertainty that often arises in evidence
INTELLIGENT TECHNIQUES FOR HANDLING UNCERTAINTY IN THE ASSESSMENT OF NEONATAL OUTCOME
Objective assessment of the neonatal outcome of labour is important, but it is a difficult
and challenging problem. It is an invaluable source of information which can be used to
provide feedback to clinicians, to audit a unit's overall performance, and can guide subsequent
neonatal care. Current methods are inadequate as they fail to distinguish damage that
occurred during labour from damage that occurred before or after labour. Analysis of the
chemical acid-base status of blood taken from the umbilical cord of an infant immediately
after delivery provides information on any damage suffered by the infant due to lack of oxygen
during labour. However, this process is complex and error prone, and requires expertise
which is not always available on labour wards.
A model of clinical expertise required for the accurate interpretation of umbilical acid-base
status was developed, and encapsulated in a rule-based expert system. This expert system
checks results to ensure their consistency, identifies whether the results come from arterial
or venous vessels, and then produces an interpretation of their meaning. This 'crisp' expert
system was validated, verified and commercially released, and has since been installed at
twenty two hospitals all around the United Kingdom.
The assessment of umbilical acid-base status is characterised by uncertainty in both the basic
data and the knowledge required for its interpretation. Fuzzy logic provides a technique
for representing both these forms of uncertainty in a single framework. A 'preliminary'
fuzzy-logic based expert system to interpret error-free results was developed, based on the
knowledge embedded in the crisp expert system. Its performance was compared against clinicians
in a validation test, but initially its performance was found to be poor in comparison
with the clinicians and inferior to the crisp expert system. An automatic tuning algorithm
was developed to modify the behaviour of the fuzzy model utilised in the expert system.
Sub-normal membership functions were used to weight terms in the fuzzy expert system in
a novel manner. This resulted in an improvement in the performance of the fuzzy expert
system to a level comparable to the clinicians, and superior to the crisp expert system.
Experimental work was carried out to evaluate the imprecision in umbilical cord acid-base
parameters. This information, in conjunction with fresh knowledge elicitation sessions, allowed
the creation of a more comprehensive fuzzy expert system, to validate and interpret
all acid-base data. This 'integrated' fuzzy expert system was tuned using the comparison
data obtained previously, and incorporated vessel identification rules and interpretation rules,
with numeric and linguistic outputs for each. The performance of each of the outputs was
evaluated in a rigorous validation study. This demonstrated excellent agreement with the
experts for the numeric outputs, and agreement on a par with the experts for the linguistic
outputs. The numeric interpretation produced by the fuzzy expert system is a novel single
dimensional measure that accurately represents the severity of acid-base results.
The development of the crisp and fuzzy expert systems represents a major achievement and
constitutes a significant contribution to the assessment of neonatal outcome.Plymouth Postgraduate Medical Schoo
Logic-based Technologies for Intelligent Systems: State of the Art and Perspectives
Together with the disruptive development of modern sub-symbolic approaches to artificial intelligence (AI), symbolic approaches to classical AI are re-gaining momentum, as more and more researchers exploit their potential to make AI more comprehensible, explainable, and therefore trustworthy. Since logic-based approaches lay at the core of symbolic AI, summarizing their state of the art is of paramount importance now more than ever, in order to identify trends, benefits, key features, gaps, and limitations of the techniques proposed so far, as well as to identify promising research perspectives. Along this line, this paper provides an overview of logic-based approaches and technologies by sketching their evolution and pointing out their main application areas. Future perspectives for exploitation of logic-based technologies are discussed as well, in order to identify those research fields that deserve more attention, considering the areas that already exploit logic-based approaches as well as those that are more likely to adopt logic-based approaches in the future
Knowledge-Based Aircraft Automation: Managers Guide on the use of Artificial Intelligence for Aircraft Automation and Verification and Validation Approach for a Neural-Based Flight Controller
The ultimate goal of this report was to integrate the powerful tools of artificial intelligence into the traditional process of software development. To maintain the US aerospace competitive advantage, traditional aerospace and software engineers need to more easily incorporate the technology of artificial intelligence into the advanced aerospace systems being designed today. The future goal was to transition artificial intelligence from an emerging technology to a standard technology that is considered early in the life cycle process to develop state-of-the-art aircraft automation systems. This report addressed the future goal in two ways. First, it provided a matrix that identified typical aircraft automation applications conducive to various artificial intelligence methods. The purpose of this matrix was to provide top-level guidance to managers contemplating the possible use of artificial intelligence in the development of aircraft automation. Second, the report provided a methodology to formally evaluate neural networks as part of the traditional process of software development. The matrix was developed by organizing the discipline of artificial intelligence into the following six methods: logical, object representation-based, distributed, uncertainty management, temporal and neurocomputing. Next, a study of existing aircraft automation applications that have been conducive to artificial intelligence implementation resulted in the following five categories: pilot-vehicle interface, system status and diagnosis, situation assessment, automatic flight planning, and aircraft flight control. The resulting matrix provided management guidance to understand artificial intelligence as it applied to aircraft automation. The approach taken to develop a methodology to formally evaluate neural networks as part of the software engineering life cycle was to start with the existing software quality assurance standards and to change these standards to include neural network development. The changes were to include evaluation tools that can be applied to neural networks at each phase of the software engineering life cycle. The result was a formal evaluation approach to increase the product quality of systems that use neural networks for their implementation
Fuzzy Logic Based Software Product Quality Model for Execution Tracing
This report presents the research carried out in the area of software product quality modelling. Its main endeavour is to consider software product quality with regard to maintainability. Supporting this aim, execution tracing quality, which is a neglected property of the software product quality at present in the quality frameworks under investigation, needs to be described by a model that offers possibilities to link to the overall software product quality frameworks.
The report includes concise description of the research objectives: (1) the thorough investigation of software product quality frameworks from the point of view of the quality property analysability with regard to execution tracing; (2) moreover, extension possibilities of software product quality frameworks, and (3) a pilot quality model developed for execution tracing quality, which is capable to capture subjective uncertainty associated with the software quality measurement.
The report closes with concluding remarks: (1) the present software quality frameworks do not exhibit any property to describe execution tracing quality, (2) execution tracing has a significant impact on the analysability of software systems that increases with the complexity, and (3) the uncertainty associated with execution tracing quality can adequately be expressed by type-1 fuzzy logic. The section potential future work outlines directions into which the research could be continued.
Findings of the research were summarized in two research reports, which were also incorporated in the thesis, and submitted for publication:
1. Tamas Galli, Francisco Chiclana, Jenny Carter, Helge Janicke, “Towards Introducing Execution Tracing to Software Product Quality Frameworks,” Acta Polytechnica Hungarica, vol. 11, no. 3, pp. 5-24, 2014. doi: 10.12700/APH.11.03.2014.03.1
2. Tamas Galli, Francisco Chiclana, Jenny Carter, Helge Janicke “Modelling Execution Tracing Quality by Means of Type-1 Fuzzy Logic,” Acta Polytechnica Hungarica, vol. 10, no. 8, pp. 49-67, 2013. doi: 10.12700/APH.10.08.2013.8.
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