Interactive graphical querying of time series and linear sequence data sets

• Authors: Harry Hochheiser;Ben Shneiderman
• Venue: Interactive graphical querying of time series and linear sequence data sets
• Year: 2003

Numerous analytic domains involve the study of measurable quantities that change over time. This widespread interest in time series data sets has led to substantial work in algorithmic strategies for querying and indexing data. Much less work has been done in the development of interactive tools for identifying patterns in these data sets.This dissertation uses a graphical mechanism for specifying queries on time series data to provide the basis for an exploration of the algorithmic and semantic issues surrounding interactive querying of time series data. Contributions of this dissertation include: (1) The definition of timeboxes—rectangular widgets that can be used in direct-manipulation Graphical User Interfaces (GUIs) to specify query constraints on time series data sets. Timeboxes are used to simultaneously specify two sets of constraints: given a set of N time series profiles, a timebox covering time periods x1…x2 (x 1 ≤ x2) and values y 1…y2 (y1 ≤ y2) will retrieve only those n ∈ N that have values y1 ≤ y ≤ y2 during all times x 1 ≤ x ≤ x2. (2) The TimeSearcher information visualization tool, which is based on the time-box query model. TimeSearcher's object-oriented architecture can easily be extended to support variants of the timebox model that provide additional expressive power. (3) The design and implementation of query models and widgets that extend the timebox model, including variable-time timeboxes (VTTs), angular queries, leaders & laggards queries, multiple search attributes, and query inversion. (4) Analysis of algorithmic issues: A comparison of multiple alternative search algorithms found that simple sequential scans outperformed geometric indices for processing timebox queries. (5) Empirical evaluation of timeboxes: Two empirical studies, each with 12 subjects, provided preliminary insight into the utility of timeboxes and led to design improvements for input and display. (6) Validation through case studies: TimeSearcher has been used by molecular biologists to explore gene expression data and nucleotide frequencies. This work has validated the utility of the tool and identified design suggestions and opportunities. (7) A framework for extending the timebox model, including the description of numerous possible extensions.