Currently, I think of my research in the two categories below.
Usability and User experience
One part of my research has concerned usability and user experience. These notions are indispensable in human-computer interaction, yet quite difficult to define and measure. Several of my publications have concerned this difficulty (e.g., IJHCS 2006, CHI 2007, CHI 2012). The main results document conceptual problems in measuring usability and the relations between various measures of usability. I have also worked on the relation between culture and usability, which exacerbate the above mentioned conceptual problems (see for instance CHI 2009 and IJHCI 2011).
I have also developed methods for working with usability in software engineering, in particularly usability evaluation methods. I have been involved in proposing and evaluating some new methods (e.g., TOCHI 2008, Interact 2007). Much of this work departs from studies of how evaluation techniques are used in practice (e.g., DIS 2006, CHI 2012). A recent paper (BIT 2010) sums up my view of the main methodological issues in usability research.
Novel Interaction Techniques
I have been particularly interested in information visualization, that is, the use of interactive computer graphics to amplify cognition. My research in this area has been on so-called overview+detail, fisheye and zoomable user interfaces, combining the implementation of novel interfaces with empirical evaluation (e.g., CHI 2006, TOCHI 2007). We have also worked on the relation of visualizations and display space (e.g., CHI 2011).
Another part of the work has emphasized developing new interaction styles and evaluating them carefully. Examples include active tangibles for table interfaces (CHI 2011) and a growing interest in shape-changing interfaces (CHI 2012).