Perspectives of visualization onboarding and guidance in VA

A typical problem in Visual Analytics(VA)is that users are highly trained experts in their application domains,but have mostly no experience in using VA systems.Thus,users often have difficulties interpreting and working with visual representations.To overcome these problems,user assistance can be incorporated into VA systems to guide experts through the analysis while closing their knowledge gaps.Different types of user assistance can be applied to extend the power of VA,enhance the user’s experience,and broaden the audience for VA.Although different approaches to visualization onboarding and guidance in VA already exist,there is a lack of research on how to design and integrate them in effective and efficient ways.Therefore,we aim at putting together the pieces of the mosaic to form a coherent whole.Based on the Knowledge-Assisted Visual Analytics model,we contribute a conceptual model of user assistance for VA by integrating the process of visualization onboarding and guidance as the two main approaches in this direction.As a result,we clarify and discuss the commonalities and differences between visualization onboarding and guidance,and discuss how they benefit from the integration of knowledge extraction and exploration.Finally,we discuss our descriptive model by applying it to VA tools integrating visualization onboarding and guidance,and showing how they should be utilized in different phases of the analysis in order to be effective and accepted by the user.

TBSSvis:Visual analytics for Temporal Blind Source Separation

Temporal Blind Source Separation(TBSS)is used to obtain the true underlying processes from noisy temporal multivariate data,such as electrocardiograms.TBSS has similarities to Principal Component Analysis(PCA)as it separates the input data into univariate components and is applicable to suitable datasets from various domains,such as medicine,finance,or civil engineering.Despite TBSS’s broad applicability,the involved tasks are not well supported in current tools,which offer only text-based interactions and single static images.Analysts are limited in analyzing and comparing obtained results,which consist of diverse data such as matrices and sets of time series.Additionally,parameter settings have a big impact on separation performance,but as a consequence of improper tooling,analysts currently do not consider the whole parameter space.We propose to solve these problems by applying visual analytics(VA)principles.Our primary contribution is a design study for TBSS,which so far has not been explored by the visualization community.We developed a task abstraction and visualization design in a user-centered design process.Task-specific assembling of well-established visualization techniques and algorithms to gain insights in the TBSS processes is our secondary contribution.We present TBSSvis,an interactive web-based VA prototype,which we evaluated extensively in two interviews with five TBSS experts.Feedback and observations from these interviews show that TBSSvis supports the actual workflow and combination of interactive visualizations that facilitate the tasks involved in analyzing TBSS results.