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An Ontology-Enabled Approach For User-Centered and Knowledge-Enabled Explanations of AI Systems

Shruthi Chari

TL;DR

An explanation ontology (EO) is created to represent literature-derived explanation types via their supporting components via their supporting components and a knowledge-augmented question-answering (QA) pipeline is implemented to support contextual explanations in a clinical setting.

Abstract

Explainable Artificial Intelligence (AI) focuses on helping humans understand the working of AI systems or their decisions and has been a cornerstone of AI for decades. Recent research in explainability has focused on explaining the workings of AI models or model explainability. There have also been several position statements and review papers detailing the needs of end-users for user-centered explainability but fewer implementations. Hence, this thesis seeks to bridge some gaps between model and user-centered explainability. We create an explanation ontology (EO) to represent literature-derived explanation types via their supporting components. We implement a knowledge-augmented question-answering (QA) pipeline to support contextual explanations in a clinical setting. Finally, we are implementing a system to combine explanations from different AI methods and data modalities. Within the EO, we can represent fifteen different explanation types, and we have tested these representations in six exemplar use cases. We find that knowledge augmentations improve the performance of base large language models in the contextualized QA, and the performance is variable across disease groups. In the same setting, clinicians also indicated that they prefer to see actionability as one of the main foci in explanations. In our explanations combination method, we plan to use similarity metrics to determine the similarity of explanations in a chronic disease detection setting. Overall, through this thesis, we design methods that can support knowledge-enabled explanations across different use cases, accounting for the methods in today's AI era that can generate the supporting components of these explanations and domain knowledge sources that can enhance them.

An Ontology-Enabled Approach For User-Centered and Knowledge-Enabled Explanations of AI Systems

TL;DR

An explanation ontology (EO) is created to represent literature-derived explanation types via their supporting components via their supporting components and a knowledge-augmented question-answering (QA) pipeline is implemented to support contextual explanations in a clinical setting.

Abstract

Explainable Artificial Intelligence (AI) focuses on helping humans understand the working of AI systems or their decisions and has been a cornerstone of AI for decades. Recent research in explainability has focused on explaining the workings of AI models or model explainability. There have also been several position statements and review papers detailing the needs of end-users for user-centered explainability but fewer implementations. Hence, this thesis seeks to bridge some gaps between model and user-centered explainability. We create an explanation ontology (EO) to represent literature-derived explanation types via their supporting components. We implement a knowledge-augmented question-answering (QA) pipeline to support contextual explanations in a clinical setting. Finally, we are implementing a system to combine explanations from different AI methods and data modalities. Within the EO, we can represent fifteen different explanation types, and we have tested these representations in six exemplar use cases. We find that knowledge augmentations improve the performance of base large language models in the contextualized QA, and the performance is variable across disease groups. In the same setting, clinicians also indicated that they prefer to see actionability as one of the main foci in explanations. In our explanations combination method, we plan to use similarity metrics to determine the similarity of explanations in a chronic disease detection setting. Overall, through this thesis, we design methods that can support knowledge-enabled explanations across different use cases, accounting for the methods in today's AI era that can generate the supporting components of these explanations and domain knowledge sources that can enhance them.

Paper Structure

This paper contains 100 sections, 35 figures, 45 tables, 4 algorithms.

Figures (35)

  • Figure 1: Users needs for explainability are diverse and depend on the use case and question being asked by domain experts / end-users in that use case. Illustrated here is different needs for explanations by two different user groups of A) Customer and B) Loan Officer, and also seen is how an explanation interface, C) needs to be tailored for different explanation types to show for these two user groups. Reproduced from: S. Chari, O. Seneviratne, M. Ghalwash, S. Shirai, D.M. Gruen, P. Meyer, P. Chakraborty and D.L. McGuinness, "Explanation ontology: A general-purpose, semantic representation for supporting user-centered explanations," Semantic Web J., vol. pre-press, pp. 1 - 31, May 2023, doi: 10.3233/SW-233282, with permission from IOS Press. ©2023
  • Figure 2: Core model of the Explanation Ontology that ties together system-, interface- and user- dependencies of explanations. Reproduced from S. Chari, O. Seneviratne, M. Ghalwash, S. Shirai, D.M. Gruen, P. Meyer, P. Chakraborty and D.L. McGuinness, "Explanation ontology: A general-purpose, semantic representation for supporting user-centered explanations," Semantic Web J., vol. Pre-press, pp. 1 - 31, May 2023, doi: 10.3233/SW-233282, with permission from IOS Press. © 2023
  • Figure 3: Model explanations and their linked methods supported within the EO. Shown here in A) is the dependency of explanation methods (model explainers) on other classes in the EO model, B) the variety of model explainers and the explanation outputs they generate (e.g., saliency methods provide local explanations) and finally C) the dependence of a user-centered explanation, contrastive explanation, on the model explanation outputs. Reproduced from S. Chari, O. Seneviratne, M. Ghalwash, S. Shirai, D.M. Gruen, P. Meyer, P. Chakraborty and D.L. McGuinness, "Explanation ontology: A general-purpose, semantic representation for supporting user-centered explanations," Semantic Web J., vol. Pre-press, pp. 1 - 31, May 2023, doi: 10.3233/SW-233282, with permission from IOS Press. © 2023
  • Figure 4: A scientific explanation for drug recommendation modelled by the EO.
  • Figure 5: A contextual explanation in a food recommender system modelled by the EO. Reproduced from S. Chari, O. Seneviratne, M. Ghalwash, S. Shirai, D.M. Gruen, P. Meyer, P. Chakraborty and D.L. McGuinness, "Explanation ontology: A general-purpose, semantic representation for supporting user-centered explanations," Semantic Web J., vol. Pre-press, pp. 1 - 31, May 2023, doi: 10.3233/SW-233282, with permission from IOS Press. © 2023
  • ...and 30 more figures

Theorems & Definitions (1)

  • Definition 4.1.1: Contextual Explanation