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@@ -1,5 +1,27 @@ |
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Abductive Learning |
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.. contents:: Table of Contents |
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Traditional supervised machine learning, e.g. classification, is predominantly data-driven. Here, a set of training examples \left\{\left(x_1, y_1\right), \ldots,\left(x_m, y_m\right)\right\} is given, where x_i \in \mathcal{X} is the i-th training instance, y_i \in \mathcal{Y} is the corresponding ground-truth label. These data are then used to train a classifier model f: \mathcal{X} \mapsto \mathcal{Y} to accurately predict the unseen data. |
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(可能加一张图,比如左边是ML,右边是ML+KB) |
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In Abductive Learning (ABL), we assume that, in addition to data as examples, there is also a knowledge base \mathcal{KB} containing domain knowledge at our disposal. We aim for the classifier f: \mathcal{X} \mapsto \mathcal{Y} to make correct predictions on unseen data, and meanwhile, the logical facts grounded by \left\{f(\boldsymbol{x}_1), \ldots, f(\boldsymbol{x}_m)\right\} should be compatible with \mathcal{KB}. |
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The process of ABL is as follows: |
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1. Upon receiving data inputs \left\{x_1,\dots,x_m\right\}, pseudo-labels \left\{f(\boldsymbol{x}_1), \ldots, f(\boldsymbol{x}_m)\right\} are obtained, predicted by a data-driven classifier model. |
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2. These pseudo-labels are then converted into logical facts \mathcal{O} that are acceptable for logical reasoning. |
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3. Conduct joint reasoning with \mathcal{KB} to find any inconsistencies. |
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4. If found, the logical facts contributing to minimal inconsistency can be identified and then modified through abductive reasoning, returning modified logical facts \Delta(\mathcal{O}) compatible with \mathcal{KB}. |
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5. These modified logical facts are converted back to the form of pseudo-labels, and used for further learning of the classifier. |
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6. As a result, the classifier is updated and replaces the previous one in the next iteration. |
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This process is repeated until the classifier is no longer updated, or the logical facts \mathcal{O} are compatible with the knowledge base. |
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The following figure illustrates this process: |
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一张图 |
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We can observe that in the above figure, the left half involves machine learning, while the right half involves logical reasoning. Thus, the entire abductive learning process is a continuous cycle of machine learning and logical reasoning. This effectively form a dual-driven (data & knowledge driven) learning system, integrating and balancing the use of machine learning and logical reasoning in a unified model. |
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