Special Issue on Highlights of ACM Intelligent User Interface (IUI) 2018

This special issue showcases ten (10) papers from the ACM Intelligent User Interface (IUI) 2018 international conference which was held in Tokyo, Japan, March 7–11th, 2018. The ACM Intelligent User Interface conference is the world-leading event on reporting outstanding research at the intersection of Human Computer Interaction (HCI) and Artificial Intelligence (AI). Along with the highest ever number of delegates attending, the IUI 2018 conference received a record number of 297 submissions, of which 68 were accepted by the international program committee (an acceptance rate of 23%). The program committee then selected seventeen (17) papers, considered among the best papers accepted into the program of ACM IUI 2018, to be invited to submit to this special issue. Each of the conference papers selected was invited to extend their work with at least 30% new material, for consideration for inclusion here. The extended versions of the papers have gone through a new review process by at least three reviewers. These extended versions allow the authors to elaborate on their excellent lines of research relevant to the ACM IUI community. As a result of this review process, we have selected ten (10) papers for this special issue, which we are pleased to introduce to the community. Members of the IUI community are interested in improving the symbiosis between humans and computers, and in making systems adapt to humans rather than the other way around. As a result, it is fitting that this special issue begins with two papers on adaptation. In the first paper “Exploring a Design Space of Graphical Adaptive Menus: Normal vs Small Screens”, the authors explore a design space based on Bertin’s eight visual variables for adaptive menus in GUIs on small screens. The case studies and experimental results with shape-changing and value-changing menus provide design guidelines for designers and practitioners seeking to realise adaptive graphical menus, such as “cloud menus”. In the paper “FourEyes: Leveraging Tool Diversity as a Means to