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Characterizing quality for science data products

December 30th, 2011

Characterizing quality for a science data product is hard. We have been working on this issue in our Multi-Sensor Data Synergy Advisor (MDSA) project with Greg Leptoukh and Chris Lynnes from the NASA Goddard Space Flight Center (GSFC). The following is my opinion on what product quality means and how it can be characterized. This work was presented as a poster at the AGU FM 2011 meeting.

Science product quality is hard to define, characterize, and act upon. Product quality reflects a comparison against standard products of a similiar kind, but it is also reflective of the fitness-for-use of the product for the end-user. Users weigh quality characteristics (e.g. accuracy, completeness, coverage, consistency, representativeness) based on their intended use for the data, and therefore quality of a product can be different based on different users’ needs and interests.  Despite the subjective nature of quality assertions, and their sensitivity to users fitness-for-use, most quality information is provided by the product producer and the subjective criteria used to determine quality is opaque, if available at all.

If users are given product quality information at all, this information usually comes in one of two forms:

  • tech reports where extensive statistical analysis is reported on very specific characteristics of the product
  • in the form of subjective and unexplained statements such as ‘good’, ‘marginal’, ‘bad’.

This is either information overload that is not easy for the user to quickly assess or a near lack of the type of information that a user needs to make their own subjective quality assessment.

Is there a smilar scenario in common-day life where users are presented with quality information that they can readily understand and act upon?

There is, and you see it every day in the supermarket.

a common application of information used to make subjective quality assessments

Nutrition Facts labels provide nutrition per serving information (e.g. amount of Total Fat, Total Carbohydrates, Protein) and how the the listed amounts per serving compare to a perspective daily diet.

The comparison to a standard 2,000 calorie diet provides the user with a simple assessment tool for the usefulness of food item in their unique diet. Quality assertions, such as whether this food is ‘good’, or ‘bad’ for the consumer’s diet are left to the consumer – but are relatively easy to make with the available information.

A ‘quality facts’ label for a scientific data product, showing computed values for community-recognized quality indicators, would go a long way towards enabling a nutrition label-like presentation of quality that is easy for science users to consume and act upon.

an early mockup of a presentation of quality information for a science data product

We have begun working on mockups of what such a presentation of quality could look like, and have constructed a basic quality model that would allow us to express in RDF the information that would be used to construct a quality facts label.

Our quality model primer presents our high-level quality model and its application to an aerosol satellite data product in detail.

Our poster presentation was a hit at AGU, where we received a great deal of positive feedback on it.  This nutrition label-like presentation is immediately familiar, and supports the metaphor of science users ‘shopping’ for the best data product to fit their needs.

We still have a long way to go on developing our presentation, but the feedback from discussions at AGU tells me that our message resonated with our intended audience.

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Fall 2010 TWC Undergraduate Research Summary

December 20th, 2010

The Fall 2010 semester marked the beginning of the Tetherless World Constellation’s undergraduate research program at Rensselaer Polytechnic Institute (RPI). Although TWC has enjoyed significant contributions from RPI undergrads since its inception, this term we stepped up our game by more “formally” incorporating a group of undergrads into TWC’s research programs, established regular meetings for the group, and with input from the students began outfitting their own space in RPI’s Winslow Building.

Patrick West, my fellow TWC undergrad research coordinator and I asked the students to blog about their work throughout the semester; with the end of term, we asked them to post summary descriptions of their work and their thoughts about the fledgling TWC undergrad research program itself. We’ve provided short summaries and links to those blogs below…

  • Cameron Helm began the term coming up to speed on SPARQL and RDF, experimented with several of the public TWC endpoints, and then worked with Phillip on basic visualizations. He then slashed his way through the tutorials on TWC’s LOGD Portal, eventually creating impressive visualizations such as this earthquake map. Cameron is very interested in the subject of data visualization and looks to do more work in this area in the future.
  • After a short TWC learning period, Dan Souza began helping doctoral candidate Evan Patton create an Android version of the Mobile Wine Agent application, with all the amazing visualization and data integration required, including Twitter and Facebook integration. Mid-semester Dan also responded to the call to help with the crash” development of the Android/iPhone TalkTracker app, in time for ISWC 2010 in early November. Dan continues to work with Evan and others for early 2011 releases of Android, iPhone/iPad Touch and iPad versions of the Mobile Wine Agent.
  • David Molik reports that he learned web coding skills, ontology creation, server installation and administration. David contributed to the development and operation of a test site for the new, semantic web savvy website for the Biological and Chemical Oceanography Data Management Office BCO-DMO of the Woods Hole Oceanographic Institute.
  • Jay Chamberlin spent much of his time working on the OPeNDAP Project, an open source server to distribute scientific data that is stored in various formats. His involvement included everything from learning his way around the OPeNAP server, to working with infrastructure such as TWC’s LDAP services, to helping migrate documentation from the previous Wiki to the new Drupal site, to actually implementing required changes to the OPeNDAP code base.
  • Phillip Ng worked on a wide variety of projects this fall, starting with basic visualizations, helping with ISWC applications, and including iPad development for the Mobile Wine Agent. Phillip’s blog is fascinating to read as he works his way through the challenges of creating applications, including his multi-part series on implementing the social media features.
  • Alexei Bulazel began working with Dominic DiFranzo on a health-related mashup using Data.gov datasets and is now working on a research paper with David on “human flesh search engine” techniques, a topic that top thinkers including Tetherless World Senior Constellation Professor Jim Hendler have explored in recent talks. Note: For more background on this phenomena, see e.g. China’s Cyberposse, NY Times (03 Mar 2010)

Many of these students will be continuing on with these or other projects at TWC in 2011; we also expect several new students to be joining the group. The entire team at the Tetherless World Constellation thanks them for their efforts and many important contributions this fall, and looks forward to being amazed by their continued great work in the coming year!

John S. Erickson, Ph.D.

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