The application of mobile computing is currently altering patterns of our behavior to a greater degree than perhaps any other invention. In combination with the introduction of power efficient wireless communication technologies, such as Bluetooth Low Energy (BLE), designers are today increasingly empowered to shape the way we interact with our physical surroundings and thus build entirely new experiences. However, our evaluations of BLE and its abilities to facilitate mobile location-based experiences in public environments revealed a number of potential problems. Most notably, the position and orientation of the user in combination with various environmental factors, such as crowds of people traversing the space, were found to cause major fluctuations of the received BLE signal strength. These issues are rendering a seamless functioning of any location-based application practically impossible. Instead of achieving seamlessness by eliminating these technical issues, we thus choose to advocate the use of a seamful approach, i.e. to reveal and exploit these problems and turn them into a part of the actual experience. In order to demonstrate the viability of this approach, we designed, implemented and evaluated the Ghost Detector - an educational location-based museum game for children. By presenting a qualitative evaluation of this game and by motivating our design decisions, this paper provides insight into some of the challenges and possible solutions connected to the process of developing location-based BLE-enabled experiences for public cultural spaces.
These deviations and discontinuities between what a mobile device observes and what actually happens, are by some researchers described as @cite_11 . Broll and Benford @cite_17 argue that seams are traditionally seen as a detracting element of user experience. As a result, developers are frequently putting significant effort into making systems as seamless as possible by eliminating or hiding any inconsistency. This is however often done at the cost of expensive investments into a better technology.
@cite_17 @cite_11
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In this paper, we question the assumption that seamless integration of computer system components is necessarily a design requirement for wearable computing and for ubiquitous computing. We explore Mark Weiser's notions of seamlessness and seamfulness', and use them in discussing the design and use of wearable and ubicomp systems. The physical nature of the systems we design reveals itself in, for example, uncertainty in sensing, limited coverage of communications infrastructure and the transformations needed to share data between heterogeneous tools and media. When such seams show through, as they inevitably do, users perceive and appropriate them for their own uses. We suggest that new opportunities for system design arise if we take fuller account of this process, and consider making it a deliberate policy to reveal and use seams. We offer examples of seams and some suggestions for seamful design, drawing from the Equator interdisciplinary research collaboration's work on ubiquitous computing and mixed reality systems. More particularly, we focus on our work in Equator's City project, on a system that lets a visitor using a PDA in a museum exhibition or cultural institution co-visit with people using virtual reality and Web versions of the same institution. Our work is strongly influenced by the vision of ubiquitous computing presented by Mark Weiser. Seamful design is a new approach to reveal and exploit inevitable technical limitations in Ubiquitous Computing technology rather than hiding them. In this paper we want to introduce its general ideas and apply them to the design of location-aware games for mobile phones. We introduce our own seamful trading-game called “Tycoon” to explore seams on this platform and show how to incorporate them into the design of mobile games. We want to evaluate how applications for the mobile phone platform which use cell-positioning can exploit seams for better interaction, gameplay and usability. In this paper, a novel content-preserving video stitching method is proposed. Video stitching has to deal with moving objects in the overlapped area (OA) which often cause problems of structural misalignment or ghost effect. To this end, the proposed method first finds an optimal seam that does not pass through the moving objects, by using the extended dynamic programing (DP) technique based on the energy minimization. Then the content-aware adaptive blending is performed which effectively reduces the color discontinuity while restricting the ghost effect caused by moving objects in the OA. In addition, to reduce the computational complexity, a partial seam-update (PSU) scheme is proposed, in which the seam is re-calculated only for a part of the seam passing through the moving object. Experimental results demonstrate that the proposed method is superior to the conventional ones in terms of both subjective quality and computational complexity. In addition, this method achieves real-time performance on mobile platform, making it applicable to consumer electronic devices. Touch screens are an increasingly common feature on personal computing devices, especially smartphones, where size and user interface advantages accrue from consolidating multiple hardware components (keyboard, number pad, etc.) into a single software definable user interface. Oily residues, or smudges, on the touch screen surface, are one side effect of touches from which frequently used patterns such as a graphical password might be inferred. In this paper we examine the feasibility of such smudge attacks on touch screens for smartphones, and focus our analysis on the Android password pattern. We first investigate the conditions (e.g., lighting and camera orientation) under which smudges are easily extracted. In the vast majority of settings, partial or complete patterns are easily retrieved. We also emulate usage situations that interfere with pattern identification, and show that pattern smudges continue to be recognizable. Finally, we provide a preliminary analysis of applying the information learned in a smudge attack to guessing an Android password pattern.