Brain-Inspired Search Engine Assistant Based on Knowledge Graph.

Search engines can quickly respond to a hyperlink list according to query keywords. However, when a query is complex, developers need to repeatedly refine search keywords and open a large number of web pages to find and summarize answers. Many research works of question and answering (Q&A) system attempt to assist search engines by providing simple, accurate, and understandable answers. However, without original semantic contexts, these answers lack explainability, making them difficult for users to trust and adopt. In this article, a brain-inspired search engine assistant named DeveloperBot based on knowledge graph is proposed, which aligns to the cognitive process of humans and has the capacity to answer complex queries with explainability. Specifically, DeveloperBot first constructs a multilayer query graph by splitting a complex multiconstraint query into several ordered constraints. Then, it models a constraint reasoning process as a subgraph search process inspired by a spreading activation model of cognitive science. In the end, novel features of the subgraph are extracted for decision-making. The corresponding reasoning subgraph and answer confidence are derived as explanations. The results of the decision-making demonstrate that DeveloperBot can estimate answers and answer confidences with high accuracy. We implement a prototype and conduct a user study to evaluate whether and how the direct answers and the explanations provided by DeveloperBot can assist developers' information needs.

Search like an expert: Reducing expertise disparity using a hybrid neural index for COVID-19 queries.

Consumers from non-medical backgrounds often look for information regarding a specific medical information need; however, they are limited by their lack of medical knowledge and may not be able to find reputable resources. As a case study, we investigate reducing this knowledge barrier to allow consumers to achieve search effectiveness comparable to that of an expert, or a medical professional, for COVID-19 related questions. We introduce and evaluate a hybrid index model that allows a consumer to formulate queries using consumer language to find relevant answers to COVID-19 questions. Our aim is to reduce performance degradation between medical professional queries and those of a consumer. We use a universal sentence embedding model to project consumer queries into the same semantic space as professional queries. We then incorporate sentence embeddings into a search framework alongside an inverted index. Documents from this index are retrieved using a novel scoring function that considers sentence embeddings and BM25 scoring. We find that our framework alleviates the expertise disparity, which we validate using an additional set of crowdsourced-consumer-queries even in an unsupervised setting. We also propose an extension of our method, where the sentence encoder is optimised in a supervised setup. Our framework allows for a consumer to search using consumer queries to match the search performance with that of a professional.

Enriching query semantics for code search with reinforcement learning.

Code search is a common practice for developers during software implementation. The challenges of accurate code search mainly lie in the knowledge gap between source code and natural language (i.e., queries). Due to the limited code-query pairs and large code-description pairs available, the prior studies based on deep learning techniques focus on learning the semantic matching relation between source code and corresponding description texts for the task, and hypothesize that the semantic gap between descriptions and user queries is marginal. In this work, we found that the code search models trained on code-description pairs may not perform well on user queries, which indicates the semantic distance between queries and code descriptions. To mitigate the semantic distance for more effective code search, we propose QueCos, a Query-enriched Code search model. QueCos learns to generate semantic enriched queries to capture the key semantics of given queries with reinforcement learning (RL). With RL, the code search performance is considered as a reward for producing accurate semantic enriched queries. The enriched queries are finally employed for code search. Experiments on the benchmark datasets show that QueCos can significantly outperform the state-of-the-art code search models.