IVAS (Improving Visual Analytics Systems) was first created when Min Chen (University of Oxford, UK) and David S. Ebert (Purdue University) were working on a research paper, in which they proposed the methodology for abstract reasoning in the design, development, evaluation, and optimization of visual analytics (VA) processes, systems, and workflows. The paper is to appear in Computer Graphics Forum and we hope that it will soon become available in the public domain.
See also: M. Chen and D. S. Ebert, "An ontological framework for supporting the design and evaluation of visual analytics systems." Computer Graphics Forum, 38(3):131-144, 2019. DOI: http://dx.doi.org/10.1111/cgf.13677. (Presented at EuroVis 2019.)
IVAS is currently maintained by Min Chen (University of Oxford, UK), who is hoping to gain more support and participation of the VA and visualization community in order for IVAS to become an ontology with a reasonably comprehensive coverage of symptoms, causes, remedies, and side-effects discovered or considered by many VA researchers and practitioners.