Query processing over data lakes is a challenging task, often requiring extensive data pre-processing activities such as data cleaning, transformation, and loading. However, the advent of Large Language Models (LLMs) has illuminated a new pathway to address these complexities by offering a unified approach to understanding the diverse datasets submerged in data lakes. In this paper, we introduce QueryArtisan, a novel LLM-powered analytic tool specifically designed for data lakes. QueryArtisan transcends traditional ETL (Extract, Transform, Load) processes by generating just-intime code for dataset-specific queries. It eliminates the need for an intermediary schema, enabling users to query the data lake directly using natural language. To achieve this, we have developed a suite of heterogeneous operators capable of processing data across various modalities. Additionally, QueryArtisan incorporates a cost model-based query optimization technique, significantly enhancing its code generation capabilities for efficient query resolution. Our extensive experimental evaluations, conducted with real-life datasets, demonstrate that QueryArtisan markedly outperforms existing solutions in terms of effectiveness, efficiency and usability.

Recently, the learning-based models are shown to outperform the conventional methods for many database tasks such as cardinality estimation, join order selection and performance tuning. However, most existing learning-based methods adopt the one-hot encoding for SQL query representation, unable to catch complicated semantic context, e.g. structure of query, database schema definition and distribution variance of columns. To address such above problem, we propose a novel pre-trained SQL representation model, called PreQR, which extends the language representation approach to SQL queries. We propose an automaton to encode the query structures, and apply a graph neural network to encode database schema information conditioned on the query. A new SQL encoder is then established by adopting the attention mechanism to support on-the-fly query-aware schema linking. Experimental results on real datasets show that replacing the one-hot encoding with our query representation can significantly improve the performances of existing learning-based models on several database tasks.

Topic modeling is nowadays widely used in text archive analytics, to find significant topics in news articles and important aspects of product comments available on the Internet. While statistical approaches, e.g. Latent Dirichlet Allocation (LDA) and its variants, are effective on building topic models on long texts, it remains difficult to identify meaningful topics over short texts, e.g. news titles and social-media messages. With the emergence and prosperity of crowdsourcing platforms, it becomes possible and easier for analytical systems to incorporate human intelligence into text analytics. Different from traditional active learning techniques, the combination of crowdsourcing and machine learning poses new challenges on the design of simple tasks for non-experts to finish in seconds. In this paper, we design a new topic modeling technique, fully exploiting the basic intuitions of humans on short text reading. By requesting human labors to subjectively measure the similarity between short text pairs, the accuracy of the topic modeling algorithms could be greatly enhanced, regardless of the prior used in the graphical model. We present well-designed short text pair selection strategies for crowdsourcing and provide analysis on the convergence property of the inference algorithm. Empirical studies show that our proposed approaches improve the result topics on English tweets and Chinese microblogs, by requesting only a small number of labels from crowd.

Telecommunication companies possess mobility information of their phone users, containing accurate locations and velocities of commuters travelling in public transportation system. Although the value of telecommunication data is well believed under the smart city vision, there is no existing solution to transform the data into actionable items for better transportation, mainly due to the lack of appropriate data utilization scheme and the limited processing capability on massive data. This paper presents the first ever system implementation of real-time public transportation crowd prediction based on telecommunication data, relying on the analytical power of advanced neural network models and the computation power of parallel streaming analytic engines. By analyzing the feeds of caller detail record (CDR) from mobile users in interested regions, our system is able to predict the number of metro passengers entering stations, the number of waiting passengers on the platforms and other important metrics on the crowd density. New techniques, including geographical-spatial data processing, weight-sharing recurrent neural network, and parallel streaming analytical programming, are employed in the system. These new techniques enable accurate and efficient prediction outputs, to meet the real-world business requirements from public transportation system.

Semi-structured data are prevalent on the web, with formats such as XML and JSON soaring in popularity due to their generality, flexibility and easy customization. However, these very same features make semi-structured data prone to a range of data quality errors, from errors in content to errors in structure. While the former has been well studied, little attention has been paid to structural errors. In this demonstration, we present TreeScope, which analyzes semi-structured data sets with the goal of automatically identifyingstructural anomaliesfrom the data. Our techniques learn robust structural models that have high support, to identify potential errors in the structure. Identified structural anomalies are then concisely summarized to provide plausible explanations of the potential errors. The goal of this demonstration is to enable an interactive exploration of the process of identifying and summarizing structural anomalies in semi-structured data sets.

Semi-structured data such as XML are popular for data interchange and storage. However, many XML documents have improper nesting where open - and close-tags are unmatched. Since some semi-structured data (e.g., Latex) have a flexible grammar and since many XML documents lack an accompanying DTD or XSD, we focus on computing a syntactic repair via the edit distance. To solve this problem, we propose a dynamic programming algorithm which takes cubic time. While this algorithm is not scalable, well-formed substrings of the data can be pruned to enable faster computation. Unfortunately, there are still cases where the dynamic program could be very expensive; hence, we give branch-and-bound algorithms based on various combinations of two heuristics, called MinCost and MaxBenefit, that trade off between accuracy and efficiency. Finally, we experimentally demonstrate the performance of these algorithms on real data.

Graphs are popular models for representing complex structure data and similarity search for graphs has become a fundamental research problem. Many techniques have been proposed to support similarity search based on the graph edit distance. However, they all suffer from certain drawbacks: high computational complexity, poor scalability in terms of database size, or not taking full advantage of indexes. To address these problems, in this paper, we propose SEGOS, an indexing and query processing framework for graph similarity search. First, an effective two-level index is constructed off-line based on sub-unit decomposition of graphs. Then, a novel search strategy based on the index is proposed. Two algorithms adapted from TA and CA methods are seamlessly integrated into the proposed strategy to enhance graph search. More specially, the proposed framework is easy to be pipelined to support continuous graph pruning. Extensive experiments are conducted on two real datasets to evaluate the effectiveness and scalability of our approaches.

The online travel services and resources are far from well organized and integrated. Trip planning is still a laborious job requiring interaction with a combination of services such as travel guides, personal travel blogs, map services and public transportation to piece together an itinerary. To facilitate this process, we have designed a cross-service travel engine for trip planners. Our system seamlessly and semantically integrates various types of travel services and resources based on a geographical ontology. We also built a user-friendly visualization tool for travellers to conveniently browse and design personal itineraries on Google Maps.