No Arabic abstract
Exploratory data science largely happens in computational notebooks with dataframe API, such as pandas, that support flexible means to transform, clean, and analyze data. Yet, visually exploring data in dataframes remains tedious, requiring substantial programming effort for visualization and mental effort to determine what analysis to perform next. We propose Lux, an always-on framework for accelerating visual insight discovery in data science workflows. When users print a dataframe in their notebooks, Lux recommends visualizations to provide a quick overview of the patterns and trends and suggests promising analysis directions. Lux features a high-level language for generating visualizations on-demand to encourage rapid visual experimentation with data. We demonstrate that through the use of a careful design and three system optimizations, Lux adds no more than two seconds of overhead on top of pandas for over 98% of datasets in the UCI repository. We evaluate Lux in terms of usability via a controlled first-use study and interviews with early adopters, finding that Lux helps fulfill the needs of data scientists for visualization support within their dataframe workflows. Lux has already been embraced by data science practitioners, with over 1.9k stars on Github within its first 15 months.
As the rate of data collection continues to grow rapidly, developing visualization tools that scale to immense data sets is a serious and ever-increasing challenge. Existing approaches generally seek to decouple storage and visualization systems, performing just-in-time data reduction to transparently avoid overloading the visualizer. We present a new architecture in which the visualizer and data store are tightly coupled. Unlike systems that read raw data from storage, the performance of our system scales linearly with the size of the final visualization, essentially independent of the size of the data. Thus, it scales to massive data sets while supporting interactive performance (sub-100 ms query latency). This enables a new class of visualization clients that automatically manage data, quickly and transparently requesting data from the underlying database without requiring the user to explicitly initiate queries. It lays a groundwork for supporting truly interactive exploration of big data and opens new directions for research on scalable information visualization systems.
Data exploration systems that provide differential privacy must manage a privacy budget that measures the amount of privacy lost across multiple queries. One effective strategy to manage the privacy budget is to compute a one-time private synopsis of the data, to which users can make an unlimited number of queries. However, existing systems using synopses are built for offline use cases, where a set of queries is known ahead of time and the system carefully optimizes a synopsis for it. The synopses that these systems build are costly to compute and may also be costly to store. We introduce Overlook, a system that enables private data exploration at interactive latencies for both data analysts and data curators. The key idea in Overlook is a virtual synopsis that can be evaluated incrementally, without extra space storage or expensive precomputation. Overlook simply executes queries using an existing engine, such as a SQL DBMS, and adds noise to their results. Because Overlooks synopses do not require costly precomputation or storage, data curators can also use Overlook to explore the impact of privacy parameters interactively. Overlook offers a rich visual query interface based on the open source Hillview system. Overlook achieves accuracy comparable to existing synopsis-based systems, while offering better performance and removing the need for extra storage.
Visual query systems (VQSs) empower users to interactively search for line charts with desired visual patterns, typically specified using intuitive sketch-based interfaces. Despite decades of past work on VQSs, these efforts have not translated to adoption in practice, possibly because VQSs are largely evaluated in unrealistic lab-based settings. To remedy this gap in adoption, we collaborated with experts from three diverse domains---astronomy, genetics, and material science---via a year-long user-centered design process to develop a VQS that supports their workflow and analytical needs, and evaluate how VQSs can be used in practice. Our study results reveal that ad-hoc sketch-only querying is not as commonly used as prior work suggests, since analysts are often unable to precisely express their patterns of interest. In addition, we characterize three essential sensemaking processes supported by our enhanced VQS. We discover that participants employ all three processes, but in different proportions, depending on the analytical needs in each domain. Our findings suggest that all three sensemaking processes must be integrated in order to make future VQSs useful for a wide range of analytical inquiries.
This paper proposes a composable Just in Time Architecture for Data Science (DS) Pipelines named JITA-4DS and associated resource management techniques for configuring disaggregated data centers (DCs). DCs under our approach are composable based on vertical integration of the application, middleware/operating system, and hardware layers customized dynamically to meet application Service Level Objectives (SLO - application-aware management). Thereby, pipelines utilize a set of flexible building blocks that can be dynamically and automatically assembled and re-assembled to meet the dynamic changes in the workloads SLOs. To assess disaggregated DCs, we study how to model and validate their performance in large-scale settings.
Data scientists across disciplines are increasingly in need of exploratory analysis tools for data sets with a high volume of features. We expand upon graph mining approaches for exploratory analysis of high-dimensional data to introduce Sirius, a visualization package for researchers to explore feature relationships among mixed data types using mutual information and network backbone sparsification. Visualizations of feature relationships aid data scientists in finding meaningful dependence among features, which can engender further analysis for feature selection, feature extraction, projection, identification of proxy variables, or insight into temporal variation at the macro scale. Graph mining approaches for feature analysis exist, such as association networks of binary features, or correlation networks of quantitative features, but mixed data types present a unique challenge for developing comprehensive feature networks for exploratory analysis. Using an information theoretic approach, Sirius supports heterogeneous data sets consisting of binary, continuous quantitative, and discrete categorical data types, and provides a user interface exploring feature pairs with high mutual information scores. We leverage a backbone sparsification approach from network theory as a dimensionality reduction technique, which probabilistically trims edges according to the local network context. Sirius is an open source Python package and Django web application for exploratory visualization, which can be deployed in data analysis pipelines. The Sirius codebase and exemplary data sets can be found at: https://github.com/compstorylab/sirius