Mining for aerosols and other particles

Klaus Mueller’s latest n-dimensional visualization work capitalizes on a decade-long collaboration with Department of Energy atmospheric chemist Alla Zelenyuk, work aimed at seeing the proverbial forest amidst trees of data.

At DOE’s Pacific Northwest National Laboratory, Zelenyuk specializes in using single-particle mass spectrometry to analyze the real-time transformations of nanoparticles. This includes atmospheric particles, such as aerosols, crucial to determining climate. Her experimental runs produce a jungle of spectral data in 450 dimensions for millions of particles.

Automated methods to analyze data with multiple variables often fail when the number of variables exceeds a dozen, Zelenyuk says. “So with 450-dimensional spectral data we needed new tools for visualizing and analyzing our data.”

Mueller, Zelenyuk and collaborators developed a two-part interactive data mining and visual analytics software package. SpectraMiner creates a unique hierarchical dynamical tree or cluster dendogram that can incorporate hundreds of clusters. Data then can be exported to ClusterSculptor so scientist can tune and explore parameters in search of important relationships.

“At each step the scientist is in control of the level of detail and the visualization format,” Mueller says, noting that the visualization tools are now used daily. “This allows them to refine, steer and control the data-mining process.”