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Figure 1. The presence of an audience impacts the user's behavior in front of a public display. High audience cardinality, glances towards the user and close physical distance between the audience and the display, contribute to increasing user-display distance, decreasing interaction time and discouraging interaction in general.

Public displays have lately become ubiquitous thanks to the decreasing cost of such technology and public policies supporting the future development of smart cities. Depending on form factor, those displays might use touchless gestural interfaces that therefore are becoming more often the object of public and private research. In this paper, we focus on touchless interactions with situated public displays, and introduce a pilot study on comparing two interfaces: an interface based on the Microsoft Human Interface Guidelines (HIG), a de facto standard in the field, and a novel interface, designed by us. Differently from the HIG, our interface displays an avatar, which does not require an activation gesture to trigger actions. Our aim is to study how the two interfaces address the so-called interaction blindness -the inability of the users to recognize the interactive capabilities of those displays. According to our pilot study, although providing a different approach, both interfaces proven effective in the proposed scenario: a public display in a campus building's hall. CCS Concepts• Human-centered computing → Interaction design → Interaction design process and methods → User interface design.

The increasing complexity of patented mechanical designs means that their novelty and inventive steps increasingly rely on interacting geometric features and how they contribute to device functions. These features and interactions are normally incorporated in patents through clear patent claims. However, patents can be difficult to interpret and understand for designers due to their legal terminologies. This suggests there is a need for greater awareness of relevant prior art amongst designers in terms of avoiding potential conflict. This paper presents a framework that helps designers obtain insight on relevant prior art and enables emerging design-prior art comparison. The framework mainly contains development of a patent graphical functional representation, a domain-specific ontology and a semantic database. The graphical representation presenting the functional reasoning of patents in terms of interacting geometric features. A domain-specific ontology enables knowledge sharing and conceptualisation, providing a standardised vocabulary for describing patented designs. By formulating patent data into a semantic database, commonality of working principles between an emerging design and prior art can be identified. This enables early identification of potential conflict and thereby could help designers steer their emerging designs away from protected solutions. A computer tool being developed based on this approach is also described.

In recent years, touchless-enabling technologies have been more and more adopted for providing public displays with gestural interactivity. This has led to the need for novel visual interfaces aimed at solving issues such as communicating interactivity to users, as well as supporting immediate usability and "natural" interactions. In this paper, we focus our investigation on a visual interface based only on the use of in-air direct manipulations. Our study aims at evaluating whether and how the presence of an Avatar that replays user's movements may decrease the perceived cognitive workload during interactions. Moreover, we conducted a brief evaluation of the relationship between the presence of the Avatar and the use of one or two hands during the interactions. To this end, we compared two versions of the same interface, differing only for the presence/absence of the user's Avatar. Our results showed that the Avatar contributes to lower the perceived cognitive workload during the interactions.