COGNITIVE ASPECTS OF COLLABORATION IN 3D VIRTUAL ENVIRONMENTS

Human-computer interaction has entered the 3D era. The most important models representing spatial information — maps — are transferred into 3D versions regarding the specific content to be displayed. Virtual worlds (VW) become promising area of interest because of possibility to dynamically modify content and multi-user cooperation when solving tasks regardless to physical presence. They can be used for sharing and elaborating information via virtual images or avatars. Attractiveness of VWs is emphasized also by possibility to measure operators’ actions and complex strategies. Collaboration in 3D environments is the crucial issue in many areas where the visualizations are important for the group cooperation. Within the specific 3D user interface the operators' ability to manipulate the displayed content is explored regarding such phenomena as situation awareness, cognitive workload and human error. For such purpose, the VWs offer a great number of tools for measuring the operators’ responses as recording virtual movement or spots of interest in the visual field. Study focuses on the methodological issues of measuring the usability of 3D VWs and comparing them with the existing principles of 2D maps. We explore operators’ strategies to reach and interpret information regarding the specific type of visualization and different level of immersion

Thermally induced wrinkling of Poly-L-lactic Acid with palladium nanolayers

Poly-L-lactic acid has lately attracted a lot of scientific interest as this material is capable of forming complex nanostructures by self organization due to wrinkling instability. This process is induced thermally on samples which were plasma-treated, sputtered with metal layers or both and therefore it offers many parameters for tweaking to achieve desired material properties. This paper focuses on poly-L-lactic acid samples coated with palladium nanolayers. After annealing these samples develop sharp wrinkles with size directly dependent on thickness of sputtered metal layer as observed by means of atomic force microscopy. Sheet resistance was also measured and has shown significant changes of electrical properties dependent both on palladium layer thickness and thermal treatment. X-ray photoelectron spectroscopy has shown that annealing does not change metal concentration on the surface of the sample it only causes rearrangement of the palladium. These data were important for choosing viable candidates for biocompatibility tests that are also presented in the paper. Annealed samples with thin palladium layers have shown significant improvement over polystyrene mock and even significant improvement of adhesion and short term proliferation (up to 60 hours) over pristine poly-L-lactic acid