Semantic Networks
How to build a Knowledge Graph from Text Using spaCy
Lionel Messi needs no introduction. Even folks who don't follow football have heard about the brilliance of one of the greatest players to have graced the sport. We have text, tons of hyperlinks, and even an audio clip. The possibilities of putting this into a use case are endless. However, there is a slight problem. This is not an ideal source of data to feed to our machines.
Dow Jones is Reimagining the News as a Knowledge Graph with Stardog
Stardog really means it when they say you can act as if the walls of the silos are not there. Debuting in version 7 is what they call Virtual Transparency, which appropriately abstracts away from the user, whether that's an application developer, a business analyst, data scientist, or anyone else who needs data, the unnecessary details of where the data is or how it's stored. Data consumers simple write a logical query, i.e. "get all purchases made in the last 30 days in the mid-atlantic, within the Electronics department for more than $100" and Stardog's platform handles the details of accessing the data where it resides and returning a single, coherent, and most important, complete result.
Learning High-order Structural and Attribute information by Knowledge Graph Attention Networks for Enhancing Knowledge Graph Embedding
Liu, Wenqiang, Cai, Hongyun, Cheng, Xu, Xie, Sifa, Yu, Yipeng, Zhang, Hanyu
The goal of representation learning of knowledge graph is to encode both entities and relations into a low-dimensional embedding spaces. Many recent works have demonstrated the benefits of knowledge graph embedding on knowledge graph completion task, such as relation extraction. However, we observe that: 1) existing method just take direct relations between entities into consideration and fails to express high-order structural relationship between entities; 2) these methods just leverage relation triples of KGs while ignoring a large number of attribute triples that encoding rich semantic information. To overcome these limitations, this paper propose a novel knowledge graph embedding method, named KANE, which is inspired by the recent developments of graph convolutional networks (GCN). KANE can capture both high-order structural and attribute information of KGs in an efficient, explicit and unified manner under the graph convolutional networks framework. Empirical results on three datasets show that KANE significantly outperforms seven state-of-arts methods. Further analysis verify the efficiency of our method and the benefits brought by the attention mechanism.
Exploiting Structural and Semantic Context for Commonsense Knowledge Base Completion
Malaviya, Chaitanya, Bhagavatula, Chandra, Bosselut, Antoine, Choi, Yejin
Automatic KB completion for commonsense knowledge graphs (e.g., ATOMIC and ConceptNet) poses unique challenges compared to the much studied conventional knowledge bases (e.g., Freebase). Commonsense knowledge graphs use free-form text to represent nodes, resulting in orders of magnitude more nodes compared to conventional KBs (18x more nodes in ATOMIC compared to Freebase (FB15K-237)). Importantly, this implies significantly sparser graph structures - a major challenge for existing KB completion methods that assume densely connected graphs over a relatively smaller set of nodes. In this paper, we present novel KB completion models that can address these challenges by exploiting the structural and semantic context of nodes. Specifically, we investigate two key ideas: (1) learning from local graph structure, using graph convolutional networks and automatic graph densification and (2) transfer learning from pre-trained language models to knowledge graphs for enhanced contextual representation of knowledge. We describe our method to incorporate information from both these sources in a joint model and provide the first empirical results for KB completion on ATOMIC and evaluation with ranking metrics on ConceptNet. Our results demonstrate the effectiveness of language model representations in boosting link prediction performance and the advantages of learning from local graph structure (+1.5 points in MRR for ConceptNet) when training on subgraphs for computational efficiency. Further analysis on model predictions shines light on the types of commonsense knowledge that language models capture well.
Beyond research data infrastructures: exploiting artificial & crowd i…
Web pages indexed by Google (plus gazillion of temporal snapshots) Embedded markup (RDFa, Microdata, Microformats) for annotation of Web pages Supports Web search & interpretation Pushed by Google, Yahoo, Bing et al (schema.org Factual errors, annotation errors (see also [Meusel et al, ESWC2015]) o Ambiguity & coreferences. Relevance: supervised coreference resolution 2.) Quality & redundancy: data fusion through supervised fact classification (SVM, knn, RF, LR, NB), diverse feature set (authority, relevance etc), considering source- (eg PageRank), entity-, & fact-level KnowMore: data fusion on markup 02/10/19 11 1. Relevance: supervised coreference resolution 2.) Quality & redundancy: data fusion through supervised fact classification (SVM, knn, RF, LR, NB), diverse feature set (authority, relevance etc), considering source- (eg PageRank), entity-, & fact-level KnowMore: data fusion on markup 02/10/19 12 1. Rich Context & Coleridge Initiative building (yet another) KG of scholarly resources & datasets 13Stefan Dietze Context/corpus: publications (currently: social sciences, SAGE Publishing) Tasks: I. Extraction/disambiguation of dataset mentions II.
DyKgChat: Benchmarking Dialogue Generation Grounding on Dynamic Knowledge Graphs
Tuan, Yi-Lin, Chen, Yun-Nung, Lee, Hung-yi
Data-driven, knowledge-grounded neural conversation models are capable of generating more informative responses. However, these models have not yet demonstrated that they can zero-shot adapt to updated, unseen knowledge graphs. This paper proposes a new task about how to apply dynamic knowledge graphs in neural conversation model and presents a novel TV series conversation corpus (DyKgChat) for the task. Also, we propose a preliminary model that selects an output from two networks at each time step: a sequence-to-sequence model (Seq2Seq) and a multi-hop reasoning model, in order to support dynamic knowledge graphs. To benchmark this new task and evaluate the capability of adaptation, we introduce several evaluation metrics and the experiments show that our proposed approach outperforms previous knowledge-grounded conversation models. The proposed corpus and model can motivate the future research directions 1 . 1 Introduction In the chitchat dialogue generation, neural conversation models (Sutskever et al., 2014; Sordoni et al., 2015; Vinyals and Le, 2015) have emerged for its capability to be fully data-driven and end-to-end trained. While the generated responses are often reasonable but general (without useful information), recent work proposed knowledge-grounded models (Eric et al., 2017; Ghazvinine-jad et al., 2018; Zhou et al., 2018b; Qian et al., 2018) to incorporate external facts in an end-to- end fashion without handcrafted slot filling. Effectively combining text and external knowledge1 The data and code are available in https://github. Nonetheless, prior work rarely analyzed the model capability of zero-shot adaptation to dynamic knowledge graphs, where the states/entities and their relations are temporal and evolve as a single time scale process.
Robustly Extracting Medical Knowledge from EHRs: A Case Study of Learning a Health Knowledge Graph
Chen, Irene Y., Agrawal, Monica, Horng, Steven, Sontag, David
Increasingly large electronic health records (EHRs) provide an opportunity to algorithmically learn medical knowledge. In one prominent example, a causal health knowledge graph could learn relationships between diseases and symptoms and then serve as a diagnostic tool to be refined with additional clinical input. Prior research has demonstrated the ability to construct such a graph from over 270,000 emergency department patient visits. In this work, we describe methods to evaluate a health knowledge graph for robustness. Moving beyond precision and recall, we analyze for which diseases and for which patients the graph is most accurate. We identify sample size and unmeasured confounders as major sources of error in the health knowledge graph. We introduce a method to leverage non-linear functions in building the causal graph to better understand existing model assumptions. Finally, to assess model generalizability, we extend to a larger set of complete patient visits within a hospital system. We conclude with a discussion on how to robustly extract medical knowledge from EHRs.
Representation Learning with Ordered Relation Paths for Knowledge Graph Completion
Zhu, Yao, Liu, Hongzhi, Wu, Zhonghai, Song, Yang, Zhang, Tao
Incompleteness is a common problem for existing knowledge graphs (KGs), and the completion of KG which aims to predict links between entities is challenging. Most existing KG completion methods only consider the direct relation between nodes and ignore the relation paths which contain useful information for link prediction. Recently, a few methods take relation paths into consideration but pay less attention to the order of relations in paths which is important for reasoning. In addition, these path-based models always ignore nonlinear contributions of path features for link prediction. To solve these problems, we propose a novel KG completion method named OPTransE. Instead of embedding both entities of a relation into the same latent space as in previous methods, we project the head entity and the tail entity of each relation into different spaces to guarantee the order of relations in the path. Meanwhile, we adopt a pooling strategy to extract nonlinear and complex features of different paths to further improve the performance of link prediction. Experimental results on two benchmark datasets show that the proposed model OPTransE performs better than state-of-the-art methods.
On Understanding Knowledge Graph Representation
Allen, Carl, Balazevic, Ivana, Hospedales, Timothy M.
Many methods have been developed to represent knowledge graph data, which implicitly exploit low-rank latent structure in the data to encode known information and enable unknown facts to be inferred. To predict whether a relationship holds between entities, their embeddings are typically compared in the latent space following a relation-specific mapping. Whilst link prediction has steadily improved, the latent structure, and hence why such models capture semantic information, remains unexplained. We build on recent theoretical interpretation of word embeddings as a basis to consider an explicit structure for representations of relations between entities. For identifiable relation types, we are able to predict properties and justify the relative performance of leading knowledge graph representation methods, including their often overlooked ability to make independent predictions.