Empirical development of a heuristic evaluation methodology for shared workspace groupware

Good real time groupware products are hard to develop, in part because evaluating their support for basic teamwork activities is difficult and costly. To address this problem, we are developing discount evaluation methods that look for groupware-specific usability problems. In a previous paper, we detailed a new set of usability heuristics that evaluators can use to inspect shared workspace groupware to see how they support teamwork. We wanted to determine whether the new heuristics could be integrated into a low-cost methodology that parallels Nielsen’s traditional heuristic evaluation (HE). To this end, we examined 27 evaluations of two shared workspace groupware systems and analysed the inspectors ’ relative performance and variability. Similar to Nielsen’s findings for traditional HE, individual inspectors discovered about a fifth of the total known teamwork problems, and that there was only modest overlap in the problems they found. Groups of three to five inspectors would report about 40– 60 % of the total known teamwork problems. These results suggest that heuristic evaluation using our groupware heuristics can be an effective and efficient method for identifying teamwork problems in shared workspace groupware systems

All across the circle : using auto-ordering to improve object transfer between mobile devices

People frequently form small groups in many social and professional situations: from conference attendees meeting at a coffee break, to siblings gathering at a family barbecue. These ad-hoc gatherings typically form into predictable geometries based on circles or circular arcs (called F-Formations). Because our lives are increasingly stored and represented by data on handheld devices, the desire to be able to share digital objects while in these groupings has increased. Using the relative position in these groups to facilitate file sharing can enable intuitive techniques such as passing or flicking. However, there is no reliable, lightweight, ad-hoc technology for detecting and representing relative locations around a circle. In this paper, we present two systems that can auto-order locations about a circle based on sensors that are standard on commodity smartphones. We tested these systems using an object-passing task in a laboratory environment against unordered and proximity-based systems, and show that our techniques are faster, are more accurate, and are preferred by users.Postprin

The effects of changing projection geometry on perception of 3D objects on and around tabletops

Funding: Natural Sciences and Engineering Research Council of Canada Networks of Centres of Excellence of Canada.Displaying 3D objects on horizontal displays can cause problems in the way that the virtual scene is presented on the 2D surface; inappropriate choices in how 3D is represented can lead to distorted images and incorrect object interpretations. We present four experiments that test 3D perception. We varied projection geometry in three ways: type of projection (perspective/parallel), separation between the observer’s point of view and the projection’s center (discrepancy), and the presence of motion parallax (with/without parallax). Projection geometry had strong effects different for each task. Reducing discrepancy is desirable for orientation judgments, but not for object recognition or internal angle judgments. Using a fixed center of projection above the table reduces error and improves accuracy in most tasks. The results have far-reaching implications for the design of 3D views on tables, in particular for multi-user applications where projections that appear correct for one person will not be perceived correctly by another.PostprintPeer reviewe

Réduire l'Aversion aux Erreurs pour Aider la Transition Novice-Expert avec Fast Tap

National audienceExpert interaction techniques such as gestures or hotkeys are more efficient than traditional WIMP techniques because it is often faster to recall a command than to navigate to it. However, many users seem to be reluctant to switch to expert interaction. We hypothesize the cause might be the aversion of making errors. To test this, we designed two intermediate modes for the FastTap interaction technique, allowing quick confirmation of what the user has retrieved from memory, and quick adjustment if she has made an error. We investigated the impact of these modes and of various error costs in a controlled study (N=36). We found that participants adopted the intermediate modes, that these modes reduced error rate when error cost was high, and that they did not substantially change selection times. However, while it validates the design of our intermediate modes, we found no evidence of greater switch to memory-based interaction, suggesting that reducing the error rate is not sufficient to promote expert use of techniques.Les techniques d'interaction expertes comme les vocabulaires gestuels ou les raccourcis clavier sont plus efficaces que les techniques WIMP traditionnelles. Il est en effet plus rapide de se rappeler une commande plutôt que de la retrouver dans des menus. Cependant, la plupart des utilisateurs semblent réticents à passer aux interactions qui se basent sur leur mémoire. Nous pensons que la cause pourrait être due à leur aversion à faire des erreurs. Pour tester cette hypothèse, nous avons conçu deux modes intermédiaires pour la technique d'interaction FastTap, qui permet de rapidement confirmer ce que l'utilisateur s'est rappelé de mémoire, et d'ajuster si une erreur a été faite. Nous avons étudié l'impact de ces deux modes intermédiaires et de différents coûts d'erreur dans une étude contrôlée (N=36). Nous avons trouvé que les participants ont adopté les modes intermédiaires, que ces modes réduisaient le taux d'erreur quand le coût de l'erreur était important, et qu'ils n'ont pas affecté de manière significative les temps de sélection. Cependant, bien que les résultats valident la conception de nos modes intermédiaires, nous n'avons pas trouvé de preuve sur un plus grand passage aux interactions qui se basent sur la mémoire. Cela suggère que réduire le taux d'erreur n'est pas suffisant pour promouvoir l'utilisation experte des techniques

Multicoil2: predicting coiled coils and their oligomerization States from sequence in the twilight zone

The alpha-helical coiled coil can adopt a variety of topologies, among the most common of which are parallel and antiparallel dimers and trimers. We present Multicoil2, an algorithm that predicts both the location and oligomerization state (two versus three helices) of coiled coils in protein sequences. Multicoil2 combines the pairwise correlations of the previous Multicoil method with the flexibility of Hidden Markov Models (HMMs) in a Markov Random Field (MRF). The resulting algorithm integrates sequence features, including pairwise interactions, through multinomial logistic regression to devise an optimized scoring function for distinguishing dimer, trimer and non-coiled-coil oligomerization states; this scoring function is used to produce Markov Random Field potentials that incorporate pairwise correlations localized in sequence. Multicoil2 significantly improves both coiled-coil detection and dimer versus trimer state prediction over the original Multicoil algorithm retrained on a newly-constructed database of coiled-coil sequences. The new database, comprised of 2,105 sequences containing 124,088 residues, includes reliable structural annotations based on experimental data in the literature. Notably, the enhanced performance of Multicoil2 is evident when tested in stringent leave-family-out cross-validation on the new database, reflecting expected performance on challenging new prediction targets that have minimal sequence similarity to known coiled-coil families. The Multicoil2 program and training database are available for download from http://multicoil2.csail.mit.edu.National Institutes of Health (U.S.) (Grant 1R01GM081871)National Science Foundation (U.S.) (Grant MCB-0347203)National Science Foundation (U.S.) (Grant 0821391

iVoLVER : Interactive Visual Language for Visualization Extraction and Reconstruction

We present the design and implementation of iVoLVER, a tool that allows users to create visualizations without textual programming. iVoLVER is designed to enable flexible acquisition of many types of data (text, colors, shapes, quantities, dates) from multiple source types (bitmap charts, webpages, photographs, SVGs, CSV files) and, within the same canvas, supports transformation of that data through simple widgets to construct interactive animated visuals. Aside from the tool, which is web-based and designed for pen and touch, we contribute the design of the interactive visual language and widgets for extraction, transformation, and representation of data. We demonstrate the flexibility and expressive power of the tool through a set of scenarios, and discuss some of the challenges encountered and how the tool fits within the current infovis tool landscape.Postprin

Thermal decomposition of allantoin as probed by matrix isolation FTIR spectroscopy

The optimized geometries, energies of the possible conformers of allantoin (2,5-dioxo-4-imidazolidinyl urea, the diureide of glyoxylic acid) as well as the barriers for conformational interconversion have been calculated using the density functional theory [DFT(B3LYP)/6-311++G(d,p)] method. The calculations predicted the existence of four conformers (gC, tT, g′C, and g′T; where the first and second symbols in the name of the conformers designate the conformation around the exocyclic NHC–NHCO and CNH–CO axes, respectively), with the gC form contributing to more than 98% of the population in gas phase at room temperature. This conformer is different from that corresponding to the monomeric unit found in crystalline RS-allantoin (g′C; Mootz, D. Acta Crystallogr.1965, 19, 726), stressing the importance of intermolecular H-bonding in determining the structure of the crystal. Upon sublimation under vacuum (10−6 mbar), the compound was found to undergo extensive decomposition to urea, isocyanic acid, NH3, and carbon. The identification of the decomposition products was made by using matrix isolation infrared spectroscopy. In consonance with the theoretical predictions, the allantoin molecules surviving thermal decomposition were found to undergo conformational isomerization and be present in the cryogenic argon matrix in both the gC and g′C conformations. The solid state room temperature infrared spectrum of allantoin was also investigated and assigned