Knowledge graphs (KGs) have rapidly emerged as an important area in AI over the last ten years. Building on a storied tradition of graphs in the AI community, a KG may be simply defined as a directed, labeled, multi-relational graph with some form of semantics. In part, this has been fueled by increased publication of structured datasets on the Web, and well-publicized successes of large-scale projects such as the Google Knowledge Graph and the Amazon Product Graph. However, another factor that is less discussed, but which has been equally instrumental in the success of KGs, is the cross-disciplinary nature of academic KG research. Arguably, because of the diversity of this research, a synthesis of how different KG research strands all tie together could serve a useful role in enabling more ‘moonshot’ research and large-scale collaborations. This review of the KG research landscape attempts to provide such a synthesis by first showing what the major strands of research are, and how those strands map to different communities, such as Natural Language Processing, Databases and Semantic Web. A unified framework is suggested in which to view the distinct, but overlapping, foci of KG research within these communities.

Equitable coverage and reliable operation of electric vehicle charging stations (EVCSs) are crucial for a just transition to a carbon-free future. Yet, a comprehensive national analysis of public EVCSs across different communities is lacking in the United States. Here, we utilize real-world reviews (n = 470,142) from a user-generated content platform to analyze public EVCSs at the census tract level. We find that disadvantaged communities (DACs) have 64% fewer public EVCSs per capita than non-DACs. This disparity rises to 73% when considering renters in multi-dwelling units. Additionally, EVCS users in DACs and urban areas experience significantly more reliability issues compared to those in non-DACs and rural areas, primarily related to hardware and technical failures. Given the limited access to home charging in DACs and their underserved public infrastructure, these findings highlight critical equity concerns and call for targeted investment in EVCS infrastructure and reliability improvements, particularly in DACs.

Web advertising related to Human Trafficking (HT) activity has been on the rise in recent years. Answering entity-centric questions over crawled HT Web corpora to assist investigators in the real world is an important social problem, involving many technical challenges. This paper describes a recent entity-centric knowledge graph effort that resulted in a semantic search engine to assist analysts and investigative experts in the HT domain. The overall approach takes as input a large corpus of advertisements crawled from the Web, structures it into an indexed knowledge graph, and enables investigators to satisfy their information needs by posing investigative search queries to a special-purpose semantic execution engine. We evaluated the search engine on real-world data collected from over 90,000 webpages, a significant fraction of which correlates with HT activity. Performance on four relevant categories of questions on a mean average precision metric were found to be promising, outperforming a learning-to-rank approach on three of the four categories. The prototype uses open-source components and scales to terabyte-scale corpora. Principles of the prototype have also been independently replicated, with similarly successful results.