Semantic Networks
A Survey on Graph Neural Networks for Knowledge Graph Completion
Knowledge Graphs are increasingly becoming popular for a variety of downstream tasks like Question Answering and Information Retrieval. However, the Knowledge Graphs are often incomplete, thus leading to poor performance. As a result, there has been a lot of interest in the task of Knowledge Base Completion. More recently, Graph Neural Networks have been used to capture structural information inherently stored in these Knowledge Graphs and have been shown to achieve SOTA performance across a variety of datasets. In this survey, we understand the various strengths and weaknesses of the proposed methodology and try to find new exciting research problems in this area that require further investigation.
KGCNs: Machine Learning over Knowledge Graphs with TensorFlow
This project introduces a novel model: the Knowledge Graph Convolutional Network (KGCN), available free to use from the GitHub repo under Apache licensing. It's written in Python, and available to install via pip from PyPi. The principal idea of this work is to forge a bridge between knowledge graphs, automated logical reasoning, and machine learning, using Grakn as the knowledge graph. A KGCN can be used to create vector representations, embeddings, of any labelled set of Grakn Things via supervised learning. There are many benefits to storing complex and interrelated data in a knowledge graph, not least that the context of each datapoint can be stored in full.
Time-aware Graph Embedding: A temporal smoothness and task-oriented approach
Xu, Yonghui, Sun, Shengjie, Miao, Yuan, Yang, Dong, Meng, Xiaonan, Hu, Yi, Wang, Ke, Song, Hengjie, Miao, Chuanyan
Knowledge graph embedding, which aims to learn the low-dimensional representations of entities and relationships, has attracted considerable research efforts recently. However, most knowledge graph embedding methods focus on the structural relationships in fixed triples while ignoring the temporal information. Currently, existing time-aware graph embedding methods only focus on the factual plausibility, while ignoring the temporal smoothness which models the interactions between a fact and its contexts, and thus can capture fine-granularity temporal relationships. This leads to the limited performance of embedding related applications. To solve this problem, this paper presents a Robustly Time-aware Graph Embedding (RTGE) method by incorporating temporal smoothness. Two major innovations of our paper are presented here. At first, RTGE integrates a measure of temporal smoothness in the learning process of the time-aware graph embedding. Via the proposed additional smoothing factor, RTGE can preserve both structural information and evolutionary patterns of a given graph. Secondly, RTGE provides a general task-oriented negative sampling strategy associated with temporally-aware information, which further improves the adaptive ability of the proposed algorithm and plays an essential role in obtaining superior performance in various tasks. Extensive experiments conducted on multiple benchmark tasks show that RTGE can increase performance in entity/relationship/temporal scoping prediction tasks.
COVID-19 Literature Knowledge Graph Construction and Drug Repurposing Report Generation
Wang, Qingyun, Li, Manling, Wang, Xuan, Parulian, Nikolaus, Han, Guangxing, Ma, Jiawei, Tu, Jingxuan, Lin, Ying, Zhang, Haoran, Liu, Weili, Chauhan, Aabhas, Guan, Yingjun, Li, Bangzheng, Li, Ruisong, Song, Xiangchen, Ji, Heng, Han, Jiawei, Chang, Shih-Fu, Pustejovsky, James, Rah, Jasmine, Liem, David, Elsayed, Ahmed, Palmer, Martha, Voss, Clare, Schneider, Cynthia, Onyshkevych, Boyan
To combat COVID-19, both clinicians and scientists need to digest the vast amount of relevant biomedical knowledge in literature to understand the disease mechanism and the related biological functions. We have developed a novel and comprehensive knowledge discovery framework, \textbf{COVID-KG} to extract fine-grained multimedia knowledge elements (entities, relations and events) from scientific literature. We then exploit the constructed multimedia knowledge graphs (KGs) for question answering and report generation, using drug repurposing as a case study. Our framework also provides detailed contextual sentences, subfigures and knowledge subgraphs as evidence. All of the data, KGs, reports, resources and shared services are publicly available.
Knowledge Graph Extraction from Videos
Mahon, Louis, Giunchiglia, Eleonora, Li, Bowen, Lukasiewicz, Thomas
Nearly all existing techniques for automated video annotation (or captioning) describe videos using natural language sentences. However, this has several shortcomings: (i) it is very hard to then further use the generated natural language annotations in automated data processing, (ii) generating natural language annotations requires to solve the hard subtask of generating semantically precise and syntactically correct natural language sentences, which is actually unrelated to the task of video annotation, (iii) it is difficult to quantitatively measure performance, as standard metrics (e.g., accuracy and F1-score) are inapplicable, and (iv) annotations are language-specific. In this paper, we propose the new task of knowledge graph extraction from videos, i.e., producing a description in the form of a knowledge graph of the contents of a given video. Since no datasets exist for this task, we also include a method to automatically generate them, starting from datasets where videos are annotated with natural language. We then describe an initial deep-learning model for knowledge graph extraction from videos, and report results on MSVD* and MSR-VTT*, two datasets obtained from MSVD and MSR-VTT using our method.
Software Engineering Event Modeling using Relative Time in Temporal Knowledge Graphs
Ahrabian, Kian, Tarlow, Daniel, Cheng, Hehuimin, Guo, Jin L. C.
We present a multi-relational temporal Knowledge Graph based on the daily interactions between artifacts in GitHub, one of the largest social coding platforms. Such representation enables posing many user-activity and project management questions as link prediction and time queries over the knowledge graph. In particular, we introduce two new datasets for i) interpolated time-conditioned link prediction and ii) extrapolated time-conditioned link/time prediction queries, each with distinguished properties. Our experiments on these datasets highlight the potential of adapting knowledge graphs to answer broad software engineering questions. Meanwhile, it also reveals the unsatisfactory performance of existing temporal models on extrapolated queries and time prediction queries in general. To overcome these shortcomings, we introduce an extension to current temporal models using relative temporal information with regards to past events.
Google starts displaying contextual info in image searches
The next time you search for and tap on an image on Google, you may see some helpful information related to what's on your screen. The company is now more deeply integrating its Knowledge Graph with pictures that it finds online. Say you're paging through photos of famous buildings as in the GIF above, you'll see a new element of the interface that highlights people, places or things related to the current picture. You can then tap on these to find out more information about them. As usual, you'll also see prompts for related searches. If you've ever searched for something and seen a panel to the side of the main interface that displays some facts related to your query, then you've seen the Knowledge Graph in action.
Coronavirus Knowledge Graph: A Case Study
Chen, Chongyan, Ebeid, Islam Akef, Bu, Yi, Ding, Ying
The emergence of the novel COVID-19 pandemic has had a significant impact on global healthcare and the economy over the past few months. The virus's rapid widespread has led to a proliferation in biomedical research addressing the pandemic and its related topics. One of the essential Knowledge Discovery tools that could help the biomedical research community understand and eventually find a cure for COVID-19 are Knowledge Graphs. The CORD-19 dataset is a collection of publicly available full-text research articles that have been recently published on COVID-19 and coronavirus topics. Here, we use several Machine Learning, Deep Learning, and Knowledge Graph construction and mining techniques to formalize and extract insights from the PubMed dataset and the CORD-19 dataset to identify COVID-19 related experts and bio-entities. Besides, we suggest possible techniques to predict related diseases, drug candidates, gene, gene mutations, and related compounds as part of a systematic effort to apply Knowledge Discovery methods to help biomedical researchers tackle the pandemic.
COVID-KG uses AI to scan thousands of studies to answer doctors' coronavirus questions
The number of studies about COVID-19 has risen exponentially from the start of the pandemic, from around 20,000 in early March to over 30,000 as of late June. In an effort to help clinicians digest the vast amount of biomedical knowledge in the literature, researchers affiliated with Columbia, Brandeis, Darpa, UCLA, and UIUC developed a framework -- COVID-KG -- that draws on papers to answer natural language questions about drug purposing and more. The sheer volume of COVID-19 research makes it difficult to sort the wheat from the chaff. Some false information has been promoted on social media and in publication venues like journals. And many results about the virus from different labs and sources are redundant, complementary, or would appear to conflict.
TransINT: Embedding Implication Rules in Knowledge Graphs with Isomorphic Intersections of Linear Subspaces
Min, So Yeon, Raghavan, Preethi, Szolovits, Peter
Knowledge Graphs (KG), composed of entities and relations, provide a structured representation of knowledge. For easy access to statistical approaches on relational data, multiple methods to embed a KG into f(KG) $\in$ R^d have been introduced. We propose TransINT, a novel and interpretable KG embedding method that isomorphically preserves the implication ordering among relations in the embedding space. Given implication rules, TransINT maps set of entities (tied by a relation) to continuous sets of vectors that are inclusion-ordered isomorphically to relation implications. With a novel parameter sharing scheme, TransINT enables automatic training on missing but implied facts without rule grounding. On a benchmark dataset, we outperform the best existing state-of-the-art rule integration embedding methods with significant margins in link Prediction and triple Classification. The angles between the continuous sets embedded by TransINT provide an interpretable way to mine semantic relatedness and implication rules among relations.