From I-Awareness to We-Awareness in CSCW

Awareness is one of the central concepts in Computer Supported Cooperative Work, though it has often been used in several different senses. Recently, researchers have begun to provide a clearer conceptualization of awareness that provides concrete guidance for the structuring of empirical studies of awareness and the development of tools to support awareness. Such conceptions, however, do not take into account newer understandings of shared intentionality among cooperating actors that recently have been defined by philosophers and empirically investigated by psychologists and psycho-linguists. These newer conceptions highlight the common ground and socially recursive inference that underwrites cooperative behavior. And it is this inference that is often seamlessly carried out in collocated work, so easy to take for granted and hence overlook, that will require computer support if such work is to be partially automated or carried out at a distance. Ignoring the inferences required in achieving common ground may thus focus a researcher or designer on surface forms of “heeding” that miss the underlying processes of intention shared in and through activity that are critical for cooperation to succeed. Shared intentionality thus provides a basis for reconceptualizing awareness in CSCW research, building on and augmenting existing notions. In this paper, we provide a philosophically grounded conception of awareness based on shared intentionality, demonstrate how it accounts for behavior in an empirical study of two individuals in collocated, tightly-coupled work, and provide implications of this conception for the design of computational systems to support tightly-coupled collaborative work.     

Distributed Job Scheduling in Rings

We give a distributed approximation algorithm for job scheduling in a ring architecture. In contrast to many other parallel scheduling models, the model we consider captures the influence of the underlying communications network by specifying that task migration from one processor to another takes time proportional to the distance between those two processors in the network. As a result, our algorithm must balance computational load and communication time. The algorithm is simple, requires no global control, and yields schedules of length at most 4.22 times optimal. We also give a lower bound on the performance of any distributed algorithm and the results of simulation experiments which suggest better performance than does our worst-case analysis.     

A Pilot Study of the VirtuSphere as a Virtual Reality Enhancement

This pilot study assessed the utility and acceptability of the VirtuSphere, a cutting edge navigation platform designed to enhance presence in virtual environments. The VirtuSphere includes a 12-ft hollow sphere within which the user stands, and it rolls within a wheeled platform, in any direction, according to the user's steps. The pilot was a within-subject crossover design comparing the VirtuSphere to standard game controller navigation. The comparison was based on locomotion in Virtual Iraq, a virtual world resembling Iraqi war zones. Participants were 10 active duty soldiers not suffering from posttraumatic stress disorder. Results indicated that there were negligible differences in sense of presence, simulator sickness, and satisfaction across the two navigation systems. Although the VirtuSphere may provide entertainment value, these results do not provide initial support for the use of the VirtuSphere to improve constructs thought to be important to behavioral health applications of virtual reality. Potential improvements to the design of the VirtuSphere are discussed.     

About the creep-fatigue interaction on the fatigue behaviour of off-axis woven-ply thermoplastic laminates at temperatures higher than Tg

The influence of plasticity and viscous effects on the fatigue behaviour of off-axis C/PPS laminates was investigated at temperatures higher than glass transition temperature. The obtained results clearly show that creep and fatigue are mutually influencing phenomena. Compared to the reference fatigue behaviour (with no prior loading), the fatigue life can be significantly extended with prior creep depending on loading conditions. Indeed, the strain accumulation seems to slow down after a long time creep preload, as if the time-dependent mechanisms were “evacuated” during this preload. The same conclusion can be drawn for the damage accumulation when the prior creep stresses are higher than the damage threshold or when the hold time is long enough, inducing significant plastic deformations. In angle-ply laminates, such deformations are associated with the reorientation of fibres. They contribute to the reduction of stress intensities, which results in increasing both fatigue life and maximum strain ɛ_max at failure during fatigue loadings.     

Marketplace substitution of Atlantic salmon for Pacific salmon in Washington State detected by DNA barcoding

Accurate identification of seafood in the marketplace is an issue of international concern, due to high rates of market substitution of cheaper or more widely available species for expensive or high-demand species. Salmon samples from stores and restaurants throughout western Washington, USA were tested using DNA sequencing of a short section of the mitochondrial cytochrome c oxidase I (COI) gene (DNA barcoding) to identify Atlantic salmon substituted for Pacific salmon. Of 99 salmon samples, 11 (11%) were Atlantic salmon sold as Pacific salmon. More than 38% of restaurant samples were mislabeled to species, while only 7% of store samples were mislabeled. Market substitution rates were significantly greater in restaurants compared to stores, and consistently greater in winter compared to spring, although not significantly. The high market substitution rate in restaurants documents a pressing need for more monitoring and enforcement specifically in restaurants. DNA barcoding is a valuable tool for rapid and definitive authentication of salmon in the marketplace, and should be more widely adopted to discourage market substitution.     

Historical photography-based computer-aided architectural design: Demolished buildings information modeling with reverse engineering functionality

This paper is about single three-point perspective historical photography-based CAAD modeling (amateur camera calibration, pose and 3-d reconstruction) of man-made environments, buildings and monuments, rich in geometrical regularity. The proposed method, gains profit from the presence in the image (historical photography) of three vanishing directions and two orthogonal object edges with known length ration, and then focuses on the graphical estimation of the skew intrinsic parameter of the uncalibrated camera (i.e. the angle of dot's x and y optical axes, in photography plane), dealing in this way even with the skew presence case (non-rectangle dot). The presence of skew is not a negligible factor in historical photography of early 20th century years, due to dot optical axes failure (carelessness manufacturing) or collapse, as well as the twist effect (distortion) from the undocumented film development process in 1920s. The graphical recovery of the skew factor is the main contribution of the paper to the pose and CAAD literature. It is shown that a single three-point perspective amateur photography, even with the presence of skew, is adequate for calibration, pose and planar structure (building façades) recovery, if the usual in building's architecture geometric clues are present (i.e. planarity, orthogonality and parallelism) and some metric data (e.g. length and width of demolished building's dimensions) are available. The proposed method was validated on a simulated cuboid and demonstrated on a number of demolished historical buildings for which only one uncalibrated (and skewed) photography was available. The accuracy evaluation shows that the method is suitable for CAAD modeling applications regarding demolished buildings and monuments of the early 20th century years (2% relative accuracy, i.e. 40 cm for a 20 m façade, included the metric data inaccuracy). The method is of interest for architecture, archaeology, reverse engineering and virtual reality.     

INTRODUCTION TO THE SPECIAL ISSUE ON CASE-BASED REASONING IN THE HEALTH SCIENCES

There has been an explosion of interest in health sciences applications of case-based reasoning (CBR), not only in the traditional CBR in medicine domain, but also in bioinformatics, enabling home health-care technologies, CBR integration, and synergies between CBR and knowledge discovery. This special issue features the best papers from the third workshop on CBR in the health sciences, held at ICCBR-05 in Madrid. It is the third in a series of exciting workshops, the first two of which were held at ICCBR-03, in Trondheim, Norway, and at ECCBR-04, in Madrid, Spain. The nine high-quality papers introduced here represent the research and experience of twenty-two authors working in eight different countries on a wide range of problems and projects. These papers illustrate some of the major trends of current research in CBR in the health sciences, and represent overall an excellent sample of the most recent advances of CBR in the health sciences.