We walk the line: Icons provisional appearances on virtual whiteboards trigger elaborative dialogue and creativity

Collaborative groupwork is a key creativity tool in industry. Digital Creativity Support Systems (CSS) have become a critical catalyst of distributed creative processes. Under laboratory conditions, this interaction design study uses an experiment to investigate the impact of apparent icon finishedness as a social affordance for elaborative dialogue, and enhanced creativity. The experiment examines the idea generation processes of 37 pairs of active managers using a synchronous CSS. Apparent finishedness is a purely presentational factor - it is completely separate from the actual substance of an idea. The results show that presenting ideas with icons made of sketchy natural lines with low perceived finishedness encourages elaborative dialogue and creativity. Low perceived finishedness icons functioned as a social affordance - they afforded the social behaviour of building upon each other’s ideas as well as more creative idea generation. This is the first study to quantitatively examine the perceived finishedness of icons. This study shows that minor changes in visual treatments significantly impact creative processes and outcomes. As co-constructive interaction is central to many collaborative behaviours across working and learning, this study has clear implications for the subtle encouragement of co-construction in computer-mediated communication.     

Using visualisation as a tool for model-based recognition

The aim of the work reported here is to build a useful toolset for 3D model-based vision on an SIMD parallel machine, the AMT DAP. Included in the toolset are facilities for model specification, manipulation and rendering using a ray-tracing approach as well as model recognition and validation using a geometrical-matching approach. In particular, an SIMD parallel version of a ray tracer and an SIMD parallel version of a bottom-up geometrical matcher are described. The ray tracer can render constructive solid geometry models and incorporates spatial subdivision of the scene. The matcher uses edge primitives recovered from scenes to match to model edges using local constraints and deals with spurious data using bin assignments. The overall toolset is illustrated by its use in closed-form testing and refinement, where the models, camera geometry and frame-to-frame motion in an image sequence generated by the ray tracer are known, but are checked and validated using geometrical matching, recognition and localisation.     

Full-range approximation of triangulated polyhedra.

We propose a new algorithm for automatically computing approximations of a given polyhedral object at different levels of details. The application for this algorithm is the display of very complex scenes. where many objects are seen with a range of varying levels of detail. Our approach is similar to the region-merging method used for image segmentation. We iteratively collapse edges, based on a measure of the geometric deviation from the initial shape. When edges are merged in the right order, this strategy produces a continuum of valid approximations of the original object, which can be used for faster rendering at vastly different scales.     

MLP Based Linear Fea ure Ex rac ion for Nonlinearly Separable Data

A novel approach to linear feature extraction is presented. Most supervised feature extraction algorithms use mean square error or other measures based on the difference between expected and actual output values as a performance criterion. The novel approach presented here uses data visualisation together with an empirical classification error (percentage of cases classified incorrectly) as performance criterion. To find the optimal data transformation weights, the Multilayer Perceptron cost function with a special regularisation term is applied. The technique proposed is verified and compared with five competing mapping techniques with respect to visualisation and different classification error criteria. For comparison, two artificial and 12 real world data sets are used.     

一种融合WebGIS和Web3D技术的实时定位系统可视化框架

随着基于位置感知技术的实时定位系统深入发展和应用,其对可视化技术的要求越来越高。如何在主流架构模式下实现复杂室内外静、动态场景目标的二三维实时可视化是其首要任务之一。分析了实时定位可视化技术的特点,结合Web GIS和Web3D技术,设计并实现了一种基于B/S架构的实时定位二三维可视化框架。按照该框架构建了体育馆人员定位系统,结合定位实验中场景渲染和目标运动轨迹效果,对该框架进行了验证。实验结果表明,该框架具有良好的实时性、双向交互性和可扩展性。     

A multi-material virtual prototyping system

This paper proposes a multi-material virtual prototyping system for digital fabrication of heterogeneous prototypes. It consists mainly of a topological hierarchy-sorting algorithm for processing slice contours, and a virtual simulation system for visualisation and optimisation of multi-material layered manufacturing (MMLM) processes. The topological hierarchy-sorting algorithm processes the hierarchy relationship of complex slice contours. It builds a parent-and-child list that defines the containment relationship of the slice contours, and subsequently arranges the contours in an appropriate sequence, which facilitates toolpath planning for MMLM by avoiding redundant tool movements. The virtual simulation system simulates MMLM processes and provides stereoscopic visualisation of the resulting multi-material prototypes for quality analysis and optimisation of the processes.     

Dynamic simulation and visualisation of coastal erosion

A key requirement for effective coastal zone management is good knowledge and prediction of land erosion rates due to encroachment of the sea. However, in addition to demarcation of the hazard through modelling and mapping, a policy of risk mitigation necessitates significant attention should also be addressed to communicating the transient behaviour of the predictions and associated uncertainty. With climate change and sea level rise implying that historical rates of change may not be a reliable guide for the future, enhanced visualisation of the evolving coastline has the potential to improve awareness of this changing risk. This visual content is developed by linking scientific modelling with the transformation of digital elevation models, and then using GIS to integrate other spatiotemporal content. The resulting high-resolution visualisations may meet demands from decision-makers for tools to communicate scientific results more effectively, due to their realism and apparent authenticity. Nevertheless they can also produces a tension with the underlying scientific content because of the necessary extrapolation of extra detail, and the lack of established procedures to communicate the resulting uncertainty in the visualisation. Coastal managers also have concerns about releasing the visualisations to the general public. These issues are explored through analysis of future cliff erosion in Norfolk on the eastern coast of Great Britain.     

Predictive Modelling of Heterogeneous Sequence Collections by Topographic Ordering of Histories

We propose a model-based approach to the twofold problem of prediction and exploratory analysis of heterogeneous symbolic sequence collections. Our model is based on seeking low entropy local representations joined together with a smooth nonlinear mixing process. Low entropy components are desirable, as they tend to be both more interpretable and more predictable. The nonlinear mixing in turn acts as a regulariser, and in addition, it creates a topographic ordering of the sequence histories, which is useful for exploratory purposes. The combination of these two modelling elements is performed through the generative probabilistic formalism, which ensures a flexible and technically sound predictive modelling framework. Unlike previous generative topographic modelling approaches for discrete data, the estimation algorithm associated with our model is designed to scale to large data sets by exploiting data sparseness. In addition, local convergence is guaranteed without the need for tuning optimisation parameters or making approximations to the non-Gaussian likelihood. These characteristics make it the first generative topographic model for discrete symbolic data with large scale real-world applicability. We analyse and discuss the relationship of our approach with a number of models and methods. We empirically demonstrate robustness against varying sample sizes, leading to significant improvements in terms of predictive performance over the state of the art. Finally we detail an application to the prediction and exploratory analysis of a large real-world web navigation sequence collection. Editor: Zoubin Ghahramani.     

Cognitive ability and information retrieval: When less is more

This paper is concerned with the use of virtual environments as a means of conveying semantic information relating to the contents of computerised textual databases. two empirical studies are reported that investigated the influence of individual differences in cognitive ability on search task performance. In the first experiment, objects (each representing a type of animal) were placed ordinally in a three-dimensional cube arrangement based on ratings of semantic similarity. Participants were required to locate a series of randomly selected objects. Contrary to prediction, participants with high associative memory were comparatively poorer performers. In a second experiment true rating distances were used to locate objects in virtual space. High spatial ability was associated with better performance and, in contrast with the results of Experiment 1, this pattern also was replicated for associative memory. Implications are discussed.     

Data Intermixing and Multi-volume Rendering

The main difference between multi-volume rendering and mono-volume rendering is data intermixing. In this paper, we present three levels of data intermixing and their rendering pipelines in direct multi-volume rendering, which discriminate image level intensity intermixing, accumulation level opacity intermixing, and illumination model level parameter intermixing. In the context of radiotherapy treatment planning, different data intermixing methods are applied to three volumes, including CT volume, Dose volume, and Segmentation volume, to compare the features of different data intermixing methods.