Alle Publikationen
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2017
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(2017): Event-based knowledge reconciliation using frame embeddings and frame similarity. In: KNOWLEDGE-BASED SYSTEMS 13, S. 192-203
Abstract: This paper proposes an evolution over MERGILO, a tool for reconciling knowledge graphs extracted from text, using graph alignment and word similarity. The reconciled knowledge graphs are typically used for multi-document summarization, or to detect knowledge evolution across document series. The main point of improvement focuses on event reconciliation i.e., reconciling knowledge graphs generated by text about two similar events described differently. In order to gather a complete semantic representation of events, we use FRED semantic web machine reader, jointly with Framester, a linguistic linked data hub represented using a novel formal semantics for frames. Framester is used to enhance the extracted event knowledge with semantic frames. We extend MERGILO with similarities based on the graph structure of semantic frames and the subsumption hierarchy of semantic roles as defined in Framester. With an effective evaluation strategy similarly as used for MERGILO, we show the improvement of the new approach (MERGILO plus semantic frame/role similarities) over the baseline.
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(2017): Event-based knowledge reconciliation using frame embeddings and frame similarity. In: KNOWLEDGE-BASED SYSTEMS 13, S. 192-203
Abstract: This paper proposes an evolution over MERGILO, a tool for reconciling knowledge graphs extracted from text, using graph alignment and word similarity. The reconciled knowledge graphs are typically used for multi-document summarization, or to detect knowledge evolution across document series. The main point of improvement focuses on event reconciliation i.e., reconciling knowledge graphs generated by text about two similar events described differently. In order to gather a complete semantic representation of events, we use FRED semantic web machine reader, jointly with Framester, a linguistic linked data hub represented using a novel formal semantics for frames. Framester is used to enhance the extracted event knowledge with semantic frames. We extend MERGILO with similarities based on the graph structure of semantic frames and the subsumption hierarchy of semantic roles as defined in Framester. With an effective evaluation strategy similarly as used for MERGILO, we show the improvement of the new approach (MERGILO plus semantic frame/role similarities) over the baseline.
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(2017): Online Recognition of Daily Activities by Color-Depth Sensing and Knowledge Models. In: SENSORS 17 (7)
Abstract: Visual activity recognition plays a fundamental role in several research fields as a way to extract semantic meaning of images and videos. Prior work has mostly focused on classification tasks, where a label is given for a video clip. However, real life scenarios require a method to browse a continuous video flow, automatically identify relevant temporal segments and classify them accordingly to target activities. This paper proposes a knowledge-driven event recognition framework to address this problem. The novelty of the method lies in the combination of a constraint-based ontology language for event modeling with robust algorithms to detect, track and re-identify people using color-depth sensing (Kinect® sensor). This combination enables to model and recognize longer and more complex events and to incorporate domain knowledge and 3D information into the same models. Moreover, the ontology-driven approach enables human understanding of system decisions and facilitates knowledge transfer across different scenes. The proposed framework is evaluated with real-world recordings of seniors carrying out unscripted, daily activities at hospital observation rooms and nursing homes. Results demonstrated that the proposed framework outperforms state-of-the-art methods in a variety of activities and datasets, and it is robust to variable and low-frame rate recordings. Further work will investigate how to extend the proposed framework with uncertainty management techniques to handle strong occlusion and ambiguous semantics, and how to exploit it to further support medicine on the timely diagnosis of cognitive disorders, such as Alzheimer’s disease.
Keywords: activities of daily living, activity recognition, assisted living, Bildsemantik, color-depth sensing, complex events, Ereigniserkennung, Ereignisverständnis, frame semantics, Informations- & Kommunikationstechnik, Knowledge representation, Kognitive Skills/Social Cognition, Mensch-Technik-Relationen (MTR), people detection and tracking, Realtechnik, senior monitoring, Sprachverstehen, Technik, Voraussetzungen für sozial angemessenes Verhalten, Weltwissen 2015
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(2015): Framing Event Variables. In: ERKENNTNIS 80, S. 31-60
Abstract: I find myself writing two papers that are due around the same time. This one develops an objection, based on Davidson’s (1967a) analysis of action reports, to truth-theoretic accounts of linguistic meaning. The other one is about the relevance of Liar Paradoxes for such accounts; see Pietroski (forthcoming). In both papers, the first numbered sentence is (1). (1) The first numbered sentence in “Framing Event Variables ” is false. But here, (1) is simply a reminder of a familiar difficulty for the idea that declarative sentences of a Human Language have truth conditions; where for these purposes, a Human Language is a spoken or signed language that any biologically normal child can acquire given an ordinary course of linguistic experience. In my view, (2) and (3) present further difficulties for this idea. (2) Alvin chased Theodore gleefully and athletically but not skillfully. (3) Theodore chased Alvin gleelessly and unathletically but skillfully. Following Davidson and others, I think action reports have “eventish ” logical forms like (2a-3a).
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