Some Augmented Reality applications require tracking physical objects to anchor virtual elements to them. Despite significant progress in computer vision, achieving robust tracking of manipulated objects remains challenging, notably due to occlusions caused by the hands. Yet the hands carry valuable information: the way an object is grasped and moved is reflected in their shape and motion. We explore the following question: can we infer changes to an object’s position and orientation from the shape and movements of the hand manipulating it? We investigate this general approach, which we call Object-from-Hand (ObHa), building three probes, drawing on insights from experimental psychology research on grasping, on our own empirical studies, and on an analysis of the extensive HOT3D dataset of everyday object manipulations. We then discuss the approach’s potential either as a complement to vision-based pose tracking solutions or as a coarse standalone pose tracking solution.

Co-located collaboration often raises challenges related to physical constraints because of e.g., stationary display setups or limited possibilities of movement. We introduce DoubleMe, an Augmented Reality system that generates virtual duplicates of collaborators’ workspaces, comprising both their displays and avatars. With DoubleMe, users maintain the layout of their own physical workspace and can position the duplicate of their collaborator’s workspace nearby. This approach alleviates spatial constraints by enabling one user to join another’s workspace without leaving their own. We report on two experiments examining the effectiveness of this approach. The first experiment investigates how avatar appearance and interaction influence user comfort and relationship dynamics. The second experiment assesses the performance benefits of duplicates over traditional co-located setups for collaborative tasks. Our findings suggest that the addition of duplicates to physical presence can enhance co-located collaboration while improving comfort.

Cooperative gestures are gestures performed by multiple users to facilitate collaboration on large interactive surfaces, such as tabletops. While previous research suggested that such gestures enhance user experience, they overlooked important aspects of user experience and, in particular, the users’ sense of agency. This paper considers two types of cooperative gestures: (i) egalitarian, where both users have the same role, and (ii) hierarchical, where one user (the leader) leads the action, and the other user (the follower) follows the leader’s actions. In a user experiment, we evaluate these types of cooperative gestures by measuring the participants’ sense of agency using intentional binding and judgment of control. Results show a decrease in the sense of agency for the followers. By contrast, leaders and users with egalitarian roles maintained their agency at the implicit sensorimotor level. We conclude with “implications for design” of these findings.

Large vertical surfaces such as wall displays allow users to work with a very large and high-resolution workspace. Such displays promote physical navigation: users can step close to the display to see details, but also move away to get a wider view of the workspace. In terms of input, current solutions usually combine direct touch on the wall with input on a handheld device, disconnecting close and distant input rather than treating it as a continuum. We present SurfAirs, which are physical controllers that users can manipulate on screen (surface input), in the air (mid-air input), and transition from the surface to the air during a single manipulation (hybrid input). We report on two user studies that compare SurfAirs’ performance with bare-hand input for both mid-air and hybrid input. Participants prefer and perform better with SurfAirs.

Wall displays are well suited for collaborative work and are often placed in rooms with ample space in front of them that remains largely unused. Augmented Reality (AR) headsets can seamlessly extend the collaboration space around the Wall. Nevertheless, it is unclear if extending Walls with AR is effective and how it may affect collaboration. We first present a prototype combining a Wall and AR headsets to extend the Wall workspace. We then use this prototype to study how users utilize the virtual space created in AR. In an experiment with 24 participants, we compare how pairs solve collaborative tasks with the Wall alone and with Wall+AR. Our qualitative and quantitative results highlight that with Wall+AR, participants use the physical space in front and around the Wall extensively, and while this creates interaction overhead, it does not impact performance and improves the user experience.

Tangibles can enrich interaction with digital surfaces. Among others, they support eyes-free control or increase awareness of other users’ actions. Tangibles have been studied in combination with horizontal surfaces such as tabletops, but not with vertical screens such as wall displays. The obvious obstacle is gravity: tangibles cannot be placed on such surfaces without falling. We present WallTokens, easy-to-fabricate tangibles to interact with a vertical surface. A WallToken is a passive token whose footprint is recognized on a tactile surface. It is equipped with a push-handle that controls a suction cup. This makes it easy for users to switch between sliding the token or attaching it to the wall. We describe how to build such tokens and how to recognize them on a tactile surface. We report on a study showing the benefits of WallTokens for manipulating virtual objects over multi-touch gestures. This project is a step towards enabling tangible interaction in a wall display context.

Shared displays are well suited to public viewing and collaboration, however they lack personal space to view private information and act without disturbing others. Combining them with Augmented Reality (AR) headsets allows interaction without altering the context on the shared display. We study a set of such interaction techniques in the context of network navigation, in particular path following, an important network analysis task. Applications abound, for example planning private trips on a network map shown on a public display. The proposed techniques allow for hands-free interaction, rendering visual aids inside the headset, in order to help the viewer maintain a connection between the AR cursor and the network that is only shown on the shared display. In two experiments on path following, we found that adding persistent connections between the AR cursor and the network on the shared display works well for high precision tasks, but more transient connections work best for lower precision tasks. More broadly, we show that combining personal AR interaction with shared displays is feasible for network navigation.

Interacting efficiently and comfortably with Augmented Reality (AR) headsets remains a major issue. We investigate the concept of mid-air pads as an alternative to gaze or direct hand input to control a cursor in windows anchored in the environment. ARPads allow users to control the cursor displayed in the headset screen through movements on a mid-air plane, which is not spatially aligned with the headset screen. We investigate a design space for ARPads, which takes into account the position of the pad relative to the user's body, and the orientation of the pad relative to that of the headset screen. Our study suggests that 1) indirect input can achieve the same performance as direct input while causing less fatigue than hand raycast, 2) an ARPad should be attached to the wrist or waist rather than to the thigh, and 3) the ARPad and the screen should have the same orientation.

Supporting many gestures on small surfaces allows users to interact remotely with complex environments such as smart homes, large remote displays, or virtual reality environments, and switching between them (e.g., AR setup in a smart home). Providing eyes-free gestures in these contexts is important as this avoids disrupting the user's visual attention. However, very few techniques enable large sets of commands on small wearable devices supporting the user's mobility and even less provide eyes-free interaction. We present Side-Crossing Menus (SCM), a gestural technique enabling large sets of gestures on %small interactive surfaces like a smartwatch. Contrary to most gestural techniques, SCM relies on broad and shallow menus that favor small and rapid gestures. We demonstrate with a first experiment that users can efficiently perform these gestures eyes-free aided with tactile cues; 95% accuracy after training 20 minutes on a representative set of 30 gestures among 172. In a second experiment, we focus on the learning of SCM gestures and do not observe significant differences with conventional Multi-stroke Marking Menus in gesture accuracy and recall rate. As both techniques utilize contrasting menu structures, our results indicate that SCM is a compelling alternative for enhancing the input capabilities of small surfaces.

Previous studies have shown that spatial memory and semantic aids can help users learn and remember gestural commands. Using the body as a support to combine both dimensions has therefore been proposed, but no formal evaluations have yet been reported. In this paper, we compare an on-body interaction technique (BodyLoci) to mid-air Marking menus in a virtual reality context. We consider three levels of semantic aids: no aid, story-making, and story-making with background images. Our results show important improvement when story-making is used, especially for Marking menus (28.5% better retention). Both techniques performed similarly without semantic aids, but Marking menus outperformed BodyLoci when using them (17.3% better retention). While our study does not show a benefit in using body support, it suggests that inducing users to leverage simple learning techniques, such as story-making, can substantially improve recall, and thus make it easier to master gestural techniques. We also analyze the strategies used by the participants for creating mnemonics to provide guidelines for future work.

Multi-scale navigation interfaces were originally designed to enable single users to explore large visual information spaces on desktop workstations. These interfaces can also be quite useful on tabletops. However, their adaptation to co-located multi-user contexts is not straightforward. The literature describes different interfaces, that only offer a limited subset of navigation actions. In this paper, we first identify a comprehensive set of actions to effectively support multi-scale navigation. We report on a guessability study in which we elicited user-defined gestures for triggering these actions, showing that there is no natural design solution, but that users heavily rely on the now-ubiquitous slide, pinch and turn gestures. We then propose two interface designs based on this set of three basic gestures: one involves two-hand variations on these gestures, the other combines them with widgets. A comparative study suggests that users can easily learn both, and that the gesture-based, visually-minimalist design is a viable option, that saves display space for other controls.

Various techniques have been proposed to faster command selection. Many of them either rely on directional gestures (e.g. Marking menus) or pointing gestures using a spatially-stable arrangement of items (e.g. FastTap). Both types of techniques are known to leverage memorization, but not necessarily for the same reasons. In this paper, we investigate whether using directions or positions affects gesture learning. Our study shows that, while recall rates are not significantly different, participants used the novice mode more often and spent more time while learning commands with directional gestures, and they also reported more physical and mental efforts. Moreover, this study also highlights the importance of semantic relationships between gestural commands and reports on the memorization strategies that were elaborated by the participants.

In multi-display environments (MDEs) that include large shared displays and desktops, users can engage in both close collaboration and parallel or personal work. To transition between the displays can be challenging in complex settings, such as crisis management rooms. To provide workspace awareness and to factilitate these transitions, we design and implement three interactions techniques that display users' activities. We explore how and where to display this activity: briefly on the shared display, or more persistently on a peripheral floor display. In a user study, motivated by the context of a crisis room where multiple operators with different roles need to cooperate, we tested the usability of the techniques and provided insights on such transitions in systems running on MDEs.

We present MarkPad, a novel interaction technique taking advantage of the touchpad. MarkPad allows creating a large number of size-dependent gestural shortcuts that can be spatially organized as desired by the user. It relies on the idea of using visual or tactile marks on the touchpad or a combination of them. Gestures start from a mark on the border and end on another mark anywhere. MarkPad does not conflict with standard interactions and provides a novice mode that acts as a rehearsal of the expert mode. A first study showed that an accuracy of 95% could be achieved for a dense configuration of tactile and/or visual marks allowing many gestures. Performance was 5% lower in a second study where the marks were only on the borders. A last study showed that borders are rarely used, even when the users are unaware of the technique. Finally, we present a working prototype and briefly report on how it was used by two users for a few months.

Multi-touch wall-sized displays afford collaborative exploration of large datasets and re-organization of digital content. However, standard touch interactions, such as dragging to move content, do not scale well to large surfaces and were not designed to support collaboration, such as passing an object around. This paper introduces CoReach, a set of collaborative gestures that combine input from multiple users in order to manipulate content, facilitate data exchange and support communication. We conducted an observational study to inform the design of CoReach, and a controlled study showing that it reduced physical fatigue and facilitated collaboration when compared with traditional multi-touch gestures. A final study assessed the value of also allowing input through a handheld tablet to manipulate content from a distance.

Large vertical displays are considered well adapted for collaboration, due to their display surface and the space in front of them that can accommodate multiple people. However, there are few studies that empirically support this assertion, and they do not quantitatively assess the differences of collaboration in front of a shared display compared to a non-shared setup, such as multiple desktops with a common view. In this paper, we compare a large shared vertical display with two desktops, when pairs of users learn to perform a path-planning task. Our results did not indicate a significant difference in learning between the two setups, but found that participants adopted different task strategies. Moreover, while pairs were overall faster with the two desktops, quality was more consistent in the vertical shared display where pairs spent more time communicating, even though there is a-priori more implicit collaboration in this setup.

Wall-displays allow multiple users to simultaneously view and analyze large amounts of information, such as the increasingly complex graphs present in domains like biology or social network analysis. We focus on how pairs explore graphs on a touch enabled wall-display using two techniques, both adapted for collaboration: a basic localized selection, and a propagation selection technique that uses the idea of diffusion/transmission from an origin node. We assess in a controlled experiment the impact of selection technique on a shortest path identification task. Pairs consistently divided space even if the task is not spatially divisible, and for the basic selection technique that has a localized visual effect, it led to parallel work that negatively impacted accuracy. The large visual footprint of the propagation technique led to close coordination, improving speed and accuracy for complex graphs only. We then observed the use of propagation on additional graph topology tasks, confirming pair strategies on spatial division and coordination.

Wall-sized displays support small groups of users working together on large amounts of data. Observational studies of such settings have shown that users adopt a range of collaboration styles, from loosely to closely coupled. Shared interaction techniques, in which multiple users perform a command collaboratively, have also been introduced to support co-located collaborative work. In this paper, we operationalize five collaborative situations with increasing levels of coupling, and test the effects of providing shared interaction support for a data manipulation task in each situation. The results show the benefits of shared interaction for close collaboration: it encourages collaborative manipulation, it is more efficient and preferred by users, and it reduces physical navigation and fatigue. We also identify the time costs caused by disruption and communication in loose collaboration and analyze the trade-offs between parallelization and close collaboration. These findings inform the design of shared interaction techniques to support collaboration on wall-sized displays.

Road traffic control centers are of vital importance to modern cities. Interviews with controllers in two such centers identified the need to incorporate the visualization of results from predictive traffic models with real traffic, to help operators choose among different interventions on the network. We explore this idea in a prototype that runs on a wall display, and supports direct touch and input from workstations and mobile devices. Apart from basic functionality to manage the current traffic such as changing traffic light duration or speed limits, the prototype incorporates traffic simulations for forecasting results of possible actions, highlighting their differences to current traffic. Based on needs identified in our interviews, we offer two techniques that visually combine simulated and real situations, taking advantage of the large display space: multiple independent views and DragMagic, a variation of magic lenses. A preliminary laboratory experiment suggests that both techniques are viable design options, even for monitoring several simulations and areas of interest, contrary to expectations from previous work. However DragMagics are easier to master.

Drag-and-drop has become ubiquitous, both on desktop computers and touch-sensitive surfaces. It is used to move and edit the geometry of elements in graphics editors, to adjust parameters using controllers such as sliders, or to manage views (e.g., moving and resizing windows, panning maps). Reverting changes made via a drag-and-drop usually entails performing the reciprocal drag-and-drop action. This can be costly as users have to remember the previous position of the object and put it back precisely. We introduce the D n D −1 model that handles all past locations of graphical objects. We redesign the Dwell-and-Spring widget to interact with this history, and explain how applications can implement D n D −1 to enable users to perform reciprocal drag-and-drop to any past location for both individual objects and groups of objects. We report on two user studies, whose results show that users understand D n D −1 , and that Dwell-and-Spring enables them to interact with this model effectively.

Ultra-high resolution wall-sized displays (“ultra-walls”) are effective for presenting large datasets, but their size and resolution make traditional pointing techniques inadequate for precision pointing. We study mid-air pointing techniques that can be combined with other, domain-specific interactions. We first explore the limits of existing single-mode remote pointing techniques and demonstrate theoretically that they do not support high-precision pointing on ultra-walls. We then explore solutions to improve mid-air pointing efficiency: a tunable acceleration function and a framework for dual-precision (DP) techniques, both with precise tuning guidelines. We designed novel pointing techniques following these guidelines, several of which outperform existing techniques in controlled experiments that involve pointing difficulties never tested prior to this work. We discuss the strengths and weaknesses of our techniques to help interaction designers choose the best technique according to the task and equipment at hand. Finally, we discuss the cognitive mechanisms that affect pointing performance with these techniques.

Millions of people go to the Web to search for geographical itineraries. Inspecting those map itineraries remains tedious because they seldom fit on screen, requiring much panning & zooming to see details. Focus+context techniques address this problem by displaying routes at a scale that allows them to fully fit on screen: users see the entire route at once, and perform magnified steering using a lens to navigate along the path, revealing additional detail. Navigation based on magnified steering has been shown to outperform pan & zoom for large steering tasks. Yet, this task remains challenging, in part because paths have a tendency to "slip off" the side of the lens. RouteLenses automatically adjust their position based on the geometry of the path that users steer through. RouteLenses make it easier for users to follow a route, yet do not constrain movements too strictly, leaving them free to move the lens away from the path to explore its surroundings.

Wall-sized displays can support data visualization and collaboration, but making them interactive is challenging. Smarties allows wall application developers to easily add interactive support to their collaborative applications. It consists of an interface running on touch mobile devices for input, a communication protocol between devices and the wall, and a library that implements the protocol and handles synchronization, locking and input conflicts. The library presents the input as an event loop with callback functions. Each touch mobile has multiple cursor controllers, each associated with keyboards, widgets and clipboards. These controllers can be assigned to specific tasks, are persistent in nature, and can be shared by multiple collaborating users for sharing work. They can control simple cursors on the wall application, or specific content (objects or groups of them). The types of associated widgets are decided by the wall application, making the mobile interface customizable by the wall application it connects to.

The advent of ultra-high resolution wall-size displays and their use for complex tasks require a more systematic analysis and deeper understanding of their advantages and drawbacks compared with desktop monitors. While previous work has mostly addressed search, visualization and sense-making tasks, we have designed an abstract classification task that involves explicit data manipulation. Based on our observations of real uses of a wall display, this task represents a large category of applications. We report on a controlled experiment that uses this task to compare physical navigation in front of a wall-size display with virtual navigation using pan-and-zoom on the desktop. Our main finding is a robust interaction effect between display type and task difficulty: while the desktop can be faster than the wall for simple tasks, the wall gains a sizable advantage as the task becomes more difficult. A follow-up study shows that other desktop techniques (overview+detail, lens) do not perform better than pan-and-zoom and are therefore slower than the wall for difficult tasks.

Rich interaction with high-resolution wall displays is not limited to remotely pointing at targets. Other relevant types of interaction include virtual navigation, text entry, and direct manipulation of control widgets. However, most techniques for remotely acquiring targets with high precision have studied remote pointing in isolation, focusing on pointing efficiency and ignoring the need to support these other types of interaction. We investigate high-precision pointing techniques capable of acquiring targets as small as 4 millimeters on a 5.5 meters wide display while leaving up to 93 % of a typical tablet device's screen space available for task-specific widgets. We compare these techniques to state-of-the-art distant pointing techniques and show that two of our techniques, a purely relative one and one that uses head orientation, perform as well or better than the best pointing-only input techniques while using a fraction of the interaction resources.

Virtual navigation on a mobile touchscreen is usually performed using finger gestures: drag and flick to scroll or pan, pinch to zoom. While easy to learn and perform, these gestures cause significant occlusion of the display. They also require users to explicitly switch between navigation mode and edit mode to either change the viewport's position in the document, or manipulate the actual content displayed in that viewport, respectively. SidePress augments mobile devices with two continuous pressure sensors co-located on one of their sides. It provides users with generic bidirectional navigation capabilities at different levels of granularity, all seamlessly integrated to act as an alternative to traditional navigation techniques, including scrollbars, drag-and-flick, or pinch-to-zoom. We describe the hardware prototype, detail the associated interaction vocabulary for different applications, and report on two laboratory studies. The first shows that users can precisely and efficiently control SidePress; the second, that SidePress can be more efficient than drag-and-flick touch gestures when scrolling large documents.

The Power-up Button is a physical button that combines pressure and proximity sensing to enable gestural interaction with one thumb. Combined with a gesture recognizer that takes the hand's anatomy into account, the Power-up Button can recognize six different mid-air gestures performed on the side of a mobile device. This gives it, for instance, enough expressive power to provide full one-handed control of interface widgets displayed on screen. This technology can complement touch input, and can be particularly useful when interacting eyes-free. It also opens up a larger design space for widget organization on screen: the button enables a more compact layout of interface components than what touch input alone would allow. This can be useful when, e.g., filling the numerous fields of a long Web form, or for very small devices.

Complex 3D virtual scenes such as CAD models of airplanes and representations of the human body are notoriously hard to visualize. Those models are made of many parts, pieces and layers of varying size, that partially occlude or even fully surround one another. We introduce Gimlenses, a multi-view, detail-in-context visualization technique that enables users to navigate complex 3D models by interactively drilling holes into their outer layers to reveal objects that are buried, possibly deep, into the scene. Those holes get constantly adjusted so as to guarantee the visibility of objects of interest from the parent view. Gimlenses can be cascaded and constrained with respect to one another, providing synchronized, complementary viewpoints on the scene. Gimlenses enable users to quickly identify elements of interest, get detailed views of those elements, relate them, and put them in a broader spatial context.

In graphical user interfaces, direct manipulation consists in incremental actions that should be reversible. Typical examples include manipulating geometrical shapes in a vector graphics editor, navigating a document using a scrollbar, or moving and resizing windows on the desktop. As in many such cases, there will not be any mechanism to undo them, requiring users to manually revert to the previous state using a similar sequence of direct manipulation actions. The associated motor and cognitive costs can be high. We argue that proper and consistent mechanisms to support undo in this context are lacking, and present Dwell-and-Spring, an interaction technique that uses the metaphor of springs to enable users to undo direct manipulations. A spring widget pops up whenever the user dwells during a press-drag-release interaction, giving her the opportunity to either cancel the current manipulation or undo the last one. The technique is generic and can easily be implemented on top of existing applications to complement the traditional undo command. Empirical evaluation shows that users quickly adopt it as soon as they discover it.

While interaction techniques that use the temporal dimension have been used for a long time, such as multiple clicks or spring-loaded widgets, more advanced uses of rhythmic patterns have received little attention in HCI. Using such temporal structures to convey information can be particularly useful in situations where the visual channel is overloaded or even not available. In this paper we introduce Rhythmic Interaction as the use of rhythms for input. We report the results of two experiments that show that (i) rhythmic patterns can be efficiently reproduced by novice users and recognized by computer algorithms, and (ii) rhythmic patterns can be memorized as efficiently as traditional shortcuts when associating them with visual commands. Overall, these results demonstrate the potential of Rhythmic Interaction and open the way to a richer repertoire of interaction techniques.

Focus+context lens-based techniques smoothly integrate two levels of detail using spatial distortion to connect the magnified region and the context. Distortion guarantees visual continuity, but causes problems of interpretation and focus targeting, partly due to the fact that most techniques are based on statically-defined, regular lens shapes, that result in far-from-optimal magnification and distortion. JellyLenses dynamically adapt to the shape of the objects of interest, providing detail-in-context visualizations of higher relevance by optimizing what regions fall into the focus, context and spatially-distorted transition regions. This both improves the visibility of content in the focus region and preserves a larger part of the context region. We describe the approach and its implementation, and report on a controlled experiment that evaluates the usability of JellyLenses compared to regular fisheye lenses, showing clear performance improvements with the new technique for a multi-scale visual search task.

When pointing to a target on a computer desktop, we may think we are taking the shortest possible path. But new shortcuts become possible if we allow the mouse cursor to jump from one edge of the screen to the opposite one, i.e., if we turn the desktop into a torus. We discuss the design of TORUSDESKTOP, a pointing technique that allows to wrap the cursor around screen edges to open this pointing backdoor. A dead zone and an off-screen cursor feedback make the technique more usable and more compatible with everyday desktop usage. We report on three controlled experiments conducted to refine the design of the technique and evaluate its performance. The results suggest clear benefits of using the backdoor when target distance is more than 80% the screen size in our experimental conditions.

Very-high-resolution wall-sized displays offer new opportunities for interacting with large data sets. While pointing on this type of display has been studied extensively, higher-level, more complex tasks such as pan-zoom navigation have received little attention. It thus remains unclear which techniques are best suited to perform multiscale navigation in these environments. Building upon empirical data gathered from studies of pan-and-zoom on desktop computers and studies of remote pointing, we identified three key factors for the design of mid-air pan-and-zoom techniques: uni- vs. bimanual interaction, linear vs. circular movements, and level of guidance to accomplish the gestures in mid-air. After an extensive phase of iterative design and pilot testing, we ran a controlled experiment aimed at better understanding the influence of these factors on task performance. Significant effects were obtained for all three factors: bimanual interaction, linear gestures and a high level of guidance resulted in significantly improved performance. Moreover, the interaction effects among some of the dimensions suggest possible combinations for more complex, real-world tasks.

Targets of only a few pixels are notoriously difficult to acquire. Despite many attempts at facilitating pointing, the reasons for this difficulty are poorly understood. We confirm a strong departure from Fitts' Law for small target acquisition using a mouse and investigate three potential sources of problems: motor accuracy, legibility, and quantization. We find that quantization is not a problem, but both motor and visual sizes are limiting factors. This suggests that small targets should be magnified in both motor and visual space to facilitate pointing. Since performance degrades exponentially as targets get very small, we further advocate the exploration of uniform, target-agnostic magnification strategies. We also confirm Welford's 1969 proposal that motor inaccuracy can be modeled by subtracting a “tremor constant” from target size. We argue for the adoption of this model, rather than Fitts' law, when reflecting on small target acquisition.

Focus+context interfaces provide in-place magnification of a region of the display, smoothly integrating the focus of attention into its surroundings. Two representations of the data exist simultaneously at two different scales, providing an alternative to classical pan & zoom for navigating multi-scale interfaces. For many practical applications however, the magnification range of focus+context techniques is too limited. This paper addresses this limitation by exploring the quantization problem: the mismatch between visual and motor precision in the magnified region. We introduce three new interaction techniques that solve this problem by

This paper reports on the design and evaluation of UIMarks, a system that lets users specify on-screen targets and associated actions by means of a graphical marking language. UIMarks supplements traditional pointing by providing an alternative mode in which users can quickly activate these marks. Associated actions can range from basic pointing facilitation to complex sequences possibly involving user interaction: one can leave a mark on a palette to make it more reachable, but the mark can also be configured to wait for a click and then automatically move the pointer back to its original location, for example. The system has been implemented on two different platforms, Metisse and OS X. We compared it to traditional pointing on a set of elementary and composite tasks in an abstract setting. Although pure pointing was not improved, the programmable automation supported by the system proved very effective.

We present DynaSpot, a new technique for acquiring targets based on the area cursor. DynaSpot couples the cursor's activation area with its speed, behaving like a point cursor at low speed or when motionless. This technique minimizes visual distraction and allows pointing anywhere in empty space without requiring an explicit mode switch, thus enabling users to perform common interactions such as region selections seamlessly. The results of our controlled experiments show that the performance of DynaSpot can be modeled by Fitts' law, and that DynaSpot significantly outperforms the point cursor and achieves, in most conditions, the same level of performance as one of the most promising techniques to date, the Bubble cursor.

Copy and move operations have long been supported by interactive desktops through various means. But the growing number of on-screen objects makes these means harder to use. In this note, we present new tools and techniques to enhance the existing ones: a selection, copy and drag history manager; two techniques to expose the user's desk and leaf through stacks of overlapping windows; and a technique that integrates the previous two with conventional drag-and-drop.

International audience

Copy-and-paste, one of the fundamental operations of modern userinterfaces, can be performed through various means (e.g. using the keyboard, mouse-based direct manipulation or menus). When users copy-and-paste between two different windows, the process is complicated by window management tasks. In this paper, we propose two new window management techniques to facilitate these tasks in the particular case of partially overlapping windows. We describe an experiment comparing four commonly-used copy-and-paste techniques under four window management conditions -- non-overlapping windows, partially overlapping windows, and partially overlapping ones with one of our two window management techniques. Results show that our new window management techniques significantly reduce task completion time for all copy-and-paste techniques. They also show that X Window copy-and-paste is faster than the other three techniques under all four window management conditions.

This article pursues a two-fold goal. First we introduce degree of goal directedness (DGD), a novel quantitative dimension for the taxonomy of navigation tasks in general. As an attempt to operationalize the DGD concept in the context of electronic documents navigation, we introduce the serial target-acquisition (STA) experimental paradigm. We suggest that DGD and the STA paradigm may usefully enrich the conceptual toolkit of HCI research for the evaluation of navigation techniques. Our second goal is to illustrate the utility of the DGD concept by showing with a concrete example, Perspective Drag, the refinement it allows in evaluating navigation techniques. We report data obtained from two experiments with the STA paradigm that cast light on what Perspective Drag is specifically good for: it is particularly suitable in realistic task contexts where navigation is less than 100% directed by its terminal goal, that is, where the user wants not only to reach a particular item but also to pick up information from the document during document traversal.

Touchstone is an open-source experiment design platform designed to help establish a solid research foundation for HCI in the area of novel interaction techniques. Touchstone includes a design platform for exploring alternative designs of controlled laboratory experiments, a run platform for running subjects and a limited analysis platform for advice and access to on-line statistics packages. Designed for HCI researchers and their students, Touchstone facilitates the process of creating new experiments, as well as replicating and extending experiments in the research literature. We tested Touchstone by designing two controlled experiments. One illustrates how to create a new experiment from scratch. The other replicates and extends a previous study of multiscale pointing interaction techniques: OrthoZoom was fastest, followed by bi-manual Pan & Zoom; SDAZ and traditional Pan & Zoom were consistently slower.

The current GUI is like a flight simulator whose camera points fixedly at right angle to the document, thus preventing users from looking ahead while navigating. We argue that perspective viewing of usual planar documents can help navigation. We analyze the scale implosion problem that arises with tilted cameras and we report the data of a formal experiment on document navigation with perspective views.

User interfaces are becoming more and more complex. Adaptable and adaptive interfaces have been proposed to address this issue and previous studies have shown that users prefer interfaces that they can adapt to self-adjusting ones. However, most existing systems provide users with little support for adapting their interfaces. Interface customization techniques are still very primitive and usually constricted to particular applications. In this paper, we present User Interface Façades, a system that provides users with simple ways to adapt, reconfigure, and re-combine existing graphical interfaces, through the use of direct manipulation techniques. The paper describes the user's view of the system, provides some technical details, and presents several examples to illustrate its potential.

Twenty years after the general adoption of overlapping windows and the desktop metaphor, modern window systems differ mainly in minor details such as window decorations or mouse and keyboard bindings. While a number of innovative window management techniques have been proposed, few of them have been evaluated and fewer have made their way into real systems. We believe that one reason for this is that most of the proposed techniques have been designed using a low fidelity approach and were never made properly available. In this paper, we present Metisse, a fully functional window system specifically created to facilitate the design, the implementation and the evaluation of innovative window management techniques. We describe the architecture of the system, some of its implementation details and present several examples that illustrate its potential.

International audience

In 1965, during the first All-Union Symposium on Group Theory, Kargapolov presented the following two problems: (a) describe the universal theory of free nilpotent groups of class m; (b) describe the universal theory of free groups (see [18, 1.28 and 1.27]). The first of these problems is still open and it is known [25] that a positive solution of this problem for an m ≤ 2 should imply the decidability of the universal theory of the field of the rationals (this last problem is equivalent to Hilbert's tenth problem for the field of the rationals which is a difficult open problem; see [17] and [20] for discussions on this problem). Regarding the second problem, Makanin proved in 1985 that a free group has a decidable universal theory (see [15] for stronger results), however, the problem of deriving an explicit description of the universal theory of free groups is open. To try to solve this problem Remeslennikov gave different characterization of finitely generated groups with the same universal theory as a noncyclic free group (see [21] and [22] and also [11]). Recently, the author proved in [8] that a free metabelian group has a decidable universal theory, but the proof of [8] does not give an explicit description of the universal theory of free metabelian groups.