Manifold topological multi-resolution analysis method

In this paper, two significant weaknesses of locally linear embedding (LLE) applied to computer vision are addressed: “intrinsic dimension” and “eigenvector meanings”. “Topological embedding” and “multi-resolution nonlinearity capture” are introduced based on mathematical analysis of topological manifolds and LLE. The manifold topological analysis (MTA) method is described and is based on “topological embedding”. MTA is a more robust method to determine the “intrinsic dimension” of a manifold with typical topology, which is important for tracking and perception understanding. The manifold multi-resolution analysis (MMA) method is based on “multi-resolution nonlinearity capture”. MMA defines LLE eigenvectors as features for pattern recognition and dimension reduction. Both MTA and MMA are proved mathematically, and several examples are provided. Applications in 3D object recognition and 3D object viewpoint space partitioning are also described.     

Digital preservation and dissemination of ancient lithic technology with modern micro-CT

Flaked stone tools were first made and used by early humans from at least 2.6 mya. By analysing temporal, geographical and species-specific variations in tool morphology scientists attempt to understand the evolution of cognition, culture and human behaviour. However, the dispersal of artefact collections around the globe in a large number of institutions makes direct study and comparison of the artefacts problematic, and therefore dependant on published drawings and photographs. The present study aims to determine whether CT could be used to create computerised (“virtual”) artefacts, and data shared with scientists and the public. In particular this study assesses whether CT would be cost effective and capture the fine surface topology created by the knapping process. Scanning could cost as little as €2 per flake. It was found that micro-CT could produce accurate high-resolution “virtual” artefacts that resolve features greater than 50 μm. Importantly, it was possible to visualise the key features of percussion, which distinguish intentionally made flakes from natural breakage. Furthermore, it was possible to recreate missing flakes (or parts thereof) from refitted groups of material by visualising void spaces. Hence it is possible to obtain a better understanding of the knapping process and obtain a glimpse of the flakes that were actually used as tools. The virtual flint artefacts are completely interactive and can be manipulated, viewed, measured and analysed as though they were in the hand and more useful to researchers than 2D drawings or photographs. The models are only 20 MB in size and can easily be distributed online, widening access to collections and access to physical specimens could be replaced with rapid stereotypes (3D prints). In addition, micro-CT imaging technology may give rise to new online “Virtual Museums” where digital data are shared widely and freely around the world, but the original material is conserved in mint condition, only to be removed for new or improved non-destructive imaging techniques.     

Can avatar and self-referencing really increase the effects of online 2-D and 3-D advertising?

Previous studies have sought insights into how websites can effectively draw sustained attention from internet users. Do different types of information presentations on webpages have different influences on users’ perceptions of the information? More precisely, can combinations of an ever greater number of advertising elements on individual websites increase consumers’ purchase intentions? The aim of this study is to explore changes in web advertising’s verbal and visual stimulation of surfers’ cognitive process, and to provide valuable information for the successful matching of advertising elements to one another. We examine optimal website design according to the personality-trait theory and resource-matching theory. Study 1 addresses the effects that combinations of various types of online advertising can have on web design factor, and to this end, we use a 2 (visual complexity: 3D advertising with an avatar, 2D advertising) × 2 (verbal complexity: with or without self-referencing that is an advertising practice to express product claims in words) factorial design. Study 2 treats personality traits (i.e., need-for-cognition and sensation seeking) as moderating variables to build the optimal portfolio regarding the “online-advertising effects” hypothesis. Our results suggest that subjects prefer medium-complex advertising comprising “3D advertising elements with an avatar” or “2D advertising elements with self-referencing”: high-sensation seekers and low-need-for-cognition viewers prefer the former, whereas low-sensation seekers and high-need-for-cognition viewers prefer the latter.     

Application of the Boltzmann kinetic equation to the eddy problems

The main purpose of this work is to investigate the feasibility of applying a kinetic approach to the problem of modeling turbulent and unstable flows. First, initial value problems with the Taylor–Green (TG) type and isotropic velocity conditions for compressible flow in two-dimensional (2D) and three-dimensional (3D) periodic domains are considered. Further, 3D direct numerical simulation of decaying isotropic turbulence is performed. Macroscopic flow quantities of interest are examined. The simulation is based on the direct numerical solution of the Boltzmann kinetic equation using an explicit–implicit scheme for the relaxation stage. Comparison with the solution of the Bhatnagar–Gross–Krook (BGK) model equation obtained by using an implicit scheme is carried out for the decaying isotropic turbulence problem and demonstrates a small difference. For the TG initial condition results show a fragmentation of the large initial eddies and subsequently the full damping of the system. Numerical data are close to the analytic solution of TG problem. A dependence of the kinetic energy on the wave number is obtained by means of the Fourier expansion of velocity components. A power-law exponent for the kinetic energy spectrum tends to the theoretical value “−3” for 2D turbulence in 2D case and to the famous Kolmogorov value “−5/3” in 3D case.     

The effects of request formats on judgment-based effort estimation

In this paper we study the effects of a change from the traditional request “How much effort is required to complete X?” to the alternative “How much can be completed in Y work-hours?”. Studies 1 and 2 report that software professionals receiving the alternative format provided much lower, and presumably more optimistic, effort estimates of the same software development work than those receiving the traditional format. Studies 3 and 4 suggest that the effect belongs to the family of anchoring effects. An implication of our results is that project managers and clients should avoid the alternative estimation request format.     

Electronic delivery of lectures in the university environment: An empirical comparison of three delivery styles

The purpose of this study was to consider the efficacy and popularity of “Virtual Lectures” (text-based, structured electronic courseware with information presented in manageable “chunks”, interaction and multimedia) and “e-Lectures” (on-screen synchrony of PowerPoint slides and recorded voice) as alternatives to traditional lectures. We considered how three modes of delivery compare when increasingly deeper forms of learning are assessed and also student reaction to electronic delivery. Fifty-eight students in three groups took three topics of a human genetics module, one in each delivery style. Results indicated no overall greater efficacy of either delivery style when all question types were taken into account but significantly different delivery-specific results depending on which level of Bloom’s taxonomy was assessed. That is, overall, questions assessing knowledge consistently achieved the highest marks followed by analysis, comprehension, evaluation and application. Students receiving traditional lectures scored significantly lower marks for comprehension questions. Students receiving Virtual Lectures scored high for knowledge, comprehension and application but significantly lower for analysis and evaluation questions. The e-Lectures scored high for knowledge questions and were the median for all question types except application. Questionnaire analysis revealed a preference for traditional lectures over computer-based but nevertheless an appreciation of the advantages offered by them.     

Execution infrastructure for normative virtual environments

Virtual Institutions (VIs) have proven to be adequate to engineer applications where participants can be humans and software agents. VIs combine Electronic Institutions (EIs) and 3D Virtual Worlds (VWs). In this context, Electronic Institutions are used to establish the regulations that structure interactions and support software agent participation while Virtual Worlds facilitate human participation. In this paper we propose Virtual Institution eXEcution Environment (VIXEE) as an innovative communication infrastructure for VIs. Using VIXEE to connect Virtual Worlds and EI opens EI to humans, providing a fully operational and comprehensive environment. The main features of the infrastructure are (i) the causal connection between Virtual Worlds and Electronic Institutions, (ii) the automatic generation and update of the VIs' 3D visualization and (iii) the simultaneous participation of users from different virtual world platforms. We illustrate the execution of VIXEE system in a simple eAuction house example and use this example to evaluate the performance of our solution.     

A Virtual World Grammar for automatic generation of virtual worlds

Hybrid systems such as those that combine 3D virtual worlds and organization based multiagent systems add new visual and communication features for multiuser applications. The design of such hybrid and dynamic systems is a challenging task. In this paper, we propose a system that can automatically generate a 3D virtual world (VW) from an organization based multiagent system (MAS) specification that establishes the activities participants can engage on. Both shape grammar and virtual world paradigms inspired us to propose a Virtual World Grammar (VWG) to support the generation process of a virtual world design. A VWG includes semantic information about both MAS specification and shape grammar elements. This information, along with heuristics and validations, guides the VW generation producing functional designs. To support the definition and execution of a Virtual World Grammar, we have developed a so named Virtual World Builder Toolkit (VWBT). We illustrate this process by generating a 3D visualization of a virtual institution from its specification.     

The immersive impact of meta-media in a virtual world

With the increasing importance of virtual settings, we observe a complexification of the media used by members of the virtual communities. Using as the model the Star Wars Role-Play community of the virtual environment of Second Life, and a related news-styled blog, the “Galactic News Network”, we analysed here the impact of this media complexification on immersion process. Specifically, we analysed how meta-media can act on virtual community behavior, and on the immersive potential of the virtual world. We combined “out-of-world” analysis of the blog, and “in-world” qualitative and quantitative evaluation of meta-media-related social activities. Our results demonstrate that meta-media strongly contribute to reinforce the immersive potential of the virtual setting via several mechanisms: by increasing three parameters of the virtual world (cohesion, coherence, and commitment), by increasing the social density of the virtual community, and by acting on the perceived time factor. The combined “in-world” and “out-of-world” action of the meta-media increases the possibilities of inter-individual connections. The combination of 2D asynchronous media and 3D instantaneous virtual settings in a homogeneous and coherent immersive environment reinforces the immersive potential of the virtual world. Thus, meta-media seem to be a factor of long-term stabilization of social structures in virtual environments.     

VRML animated model watermarking scheme using geometry and interpolator nodes

Distinct from image and video watermarking, a watermarking scheme for 3D animation content is required in the 3D industry market for various applications. This paper develops a watermarking scheme for copyright protection and authentication of 3D animation content. A 3D animated model generally has a hierarchical structure with a number of transform nodes of a geometry node and an interpolator node for the timeline in contrast to a 3D polygon mesh model. The proposed scheme embeds not only a robust watermark into the geometry node for copyright protection but also a fragile watermark into the position and orientation interpolators for content authentication. We named the former “robust geometry watermarking” and the latter “fragile interpolator watermarking”. The proposed scheme performs the two watermarking schemes independently to realize simultaneously robust and fragile watermarked 3D animated model. Experimental results confirm that a watermark embedded by geometry watermarking robust to many attacks from commercial 3D editing tools while a watermark embedded by interpolator watermarking fragile to the same attacks.     

An Empirical Analysis of Using Text-to-Speech Software to Revise First-Year College Students’ Essays

Traditionally, composition experts have suggested reading drafts aloud as a means of revising essays; however, the method of reading drafts aloud is severely limited by a single factor: student writers do not always read what is on the page (Hartwell, 1985). Text-to-speech (TTS) software allows students to have their essays read to them so that the limiting factor of reading their own drafts aloud becomes minimized. TTS programs read what is written on the computer screen, and the result is that the students can “hear” the problems of their essays as opposed to simply “seeing” them. Nevertheless, composition researchers have not conducted any empirical studies to determine whether or not TTS is beneficial for “local” and “global” revision, nor have any studies been conducted to determine if TTS is beneficial for students above the fifth grade. This article documents an experimental study conducted at a southwestern university in the United States with fifty-one students to determine whether or not TTS software is useful in the revision process. The results show that users of TTS were as likely as users in the control group to make proofreading changes but less inclined to make local or global changes in the revision process, indicating that TTS possibly works well for proofreading but not necessarily as well for higher-order revision. Further research is recommended to determine TTS's effectiveness during a longitudinal study as well as for auditory learners and ESL students.     

Exploring Post-critical Composition: MEmorials for Afghanistan and the Lost Boys of Sudan*

This article seeks to extend the concept of “post-critical composition” through an analysis of two MEmorials, the post-critical genre Gregory Ulmer [Ulmer, Gregory L. (2005). Electronic monuments. Minneapolis: University of Minnesota Press] has been exploring for 15 years. I resist the tendency on the part of some post-critical theorists to reject the role of genres and models in favor of perpetual re-invention of genres and pedagogies with each composition. Through a combination of product analysis and process reflection, this article documents the necessary but flexible role the genre of MEmorial played in a student composition, “MEmorial for Afghanistan,” and in my own composition, “Strangers in Strange Lands: A MEmorial for the Lost Boys of Sudan*.” This essay is an extension of not only post-critical composition but also online memorialization, described by National Public Radio [National Public Radio. (2007, May 28). Online memorials to the war dead. Day to day. Retrieved June 5, 2007, from http://www.npr.org] as a “modern phenomenon” and identified by Joyce Walker [Walker, Joyce. (2007). Narratives in the database: Memorializing September 11th online. Computers and Composition 24(2), 121-153] as a potentially powerful means of encouraging “cyborg citizens.”     

The virtual library secretary: A user model-based software agent

A user model comprises knowledge of the user's past and present tasks, and is the essential element in adaptive user interfaces. Through the propagation of user models, we can take the user models into the world of software agents, and thus construct user model-based software agents. The user model approach reduces the threats of software agents penetrating a local host and the amount of data transferred. This paper presents the Virtual Library Secretary, which is a user model-based software agent system. The Virtual Library Secretary offers information retrieval and information filtering to the user. The system is part of the Virtual Secretary project. The user model is established by a simple neural network. In this way, the agent is able to learn and adapt to the user's behaviour. This paper discusses the user model concept, presents the Virtual Secretary system architecture and describes how this architecture works through the Virtual Library Secretary.The Virtual Secretary project is an on-going project at the University of Tromsø. It includes two phases: the first phase (ViSe) focuses on user model-based software agents for information filtering and agent control propagation; the second phase (ViSe2) concentrates on information integration via cooperative agents in a distributed environment. The project is partly supported by the Research Council of Norway (Grant no. 112577/431).     

Store selection criteria and sales prediction in virtual worlds

Virtual worlds (VWs) have emerged as a new context for gaming, collaboration, social networking but also commercial activity. This paper focuses on the latter, and investigates how consumers behave in this virtual context when selecting stores they visit or buy from. The paper explores store selection criteria in virtual world stores and extends earlier research in both offline and online commercial environments, taking into account the novel IT capabilities that VWs exploit. Theoretical insights drawn from the marketing and information systems literature have been used to guide the design of a survey conducted in the virtual world Second Life. In addition to identifying the factors influencing store selection, the paper investigates how these differ between shoppers and non-shoppers, and identifies the factors that affect the amount of money spent in virtual world shopping environments. The findings suggest that “Core Store Features” and “Security and Privacy” constitute the most important store selection factors in virtual environments and that sales in VWs are predicted by the frequency of visiting and the time spent within VWs’ stores. Building on these findings, the paper discusses theoretical and practical implications and further research perspectives in the context of (3D) online commerce.     

VELOS: A VR platform for ship-evacuation analysis

“Virtual Environment for Life On Ships” (VELOS) is a multi-user Virtual Reality (VR) system that aims to support designers to assess (early in the design process) passenger and crew activities on a ship for both normal and hectic conditions of operations and to improve ship design accordingly. This article focuses on presenting the novel features of VELOS related to both its VR and evacuation-specific functionalities. These features include: (i) capability of multiple users’ immersion and active participation in the evacuation process, (ii) real-time interactivity and capability for making on-the-fly alterations of environment events and crowd-behavior parameters, (iii) capability of agents and avatars to move continuously on decks, (iv) integrated framework for both the simplified and advanced method of analysis according to the IMO/MSC 1033 Circular, (v) enrichment of the ship geometrical model with a topological model suitable for evacuation analysis, (vi) efficient interfaces for the dynamic specification and handling of the required heterogeneous input data, and (vii) post-processing of the calculated agent trajectories for extracting useful information for the evacuation process. VELOS evacuation functionality is illustrated using three evacuation test cases for a ro-ro passenger ship.     

The geometry and dynamics of binary trees

The modeling of a fully populated 3D tree able to regulate dynamically remains a relatively unexplored field. A non-dimensional representation of “autoregulation” coupled with an asymmetric binary tree algorithm has been developed. The tree has a defined topology as well as a spatial representation in 3D. An analysis using a simple linearization shows the systems dynamics when perturbed away from equilibrium. Results, based on previously published work by Karch and Schreiner are presented for a variety of parameters which provide different shapes of the tree and indicate a possible mechanism for “growing” the tree in specified directions. In addition the tree, through the use of local tagging has the ability to vary its size locally via a coupled set of conservation and reverting differential equations.     

Visualizing processes on the web

In this paper, we describe 3WPS, a framework to build distributed systems that are able to monitor and interact with a process through a 3D interface that is accessible via the World Wide Web (WWW). The 3WPS is easily configurable, easily adaptable to different processes with high reuse of its software components and its distributed architecture leverages on off-the-shelf components of the WWW infrastructure such as Java applets and Virtual Reality Modeling Language (VRML) browsers. We describe the characteristics of 3WPS framework by mainly focusing on the issue of programmability and by contextually providing an example tour of its usage.     

An architectural approach to efficient 3D urban modeling

A 3D reconstruction of an urban area for Virtual Worlds (VWs) or Serious Games (SGs) requires a careful trade-off among the 3D models' realism, weight and development time. This has led us to the definition of an algorithm - the Architectonic Style Area (ASA) algorithm - for procedural generation of buildings in an urban area, based on the concept of “architectonic likelihood”, that intends to give players the sense of being in a particular city or even specific area of a city. This has a cognitive foundation in the fact that, after a visit, a tourist typically does not remember every single palace of a city, but remembers - beside the most important monuments and buildings - its general features and its architectonic styles. The algorithm extrudes 2D maps and composes façades by statistically assembling sample images of architectonic components from the target city. Components are classified in an ontology based on the classic principles of architecture. The algorithm relies on rules that encode the semantics of the ontology.The paper describes the algorithm and the related easy-to-use visual authoring tool. It also shows the results in two different projects: a SG for the promotion of the cultural heritage and a 3D movie. Results show that the approach allows keeping the realism of every single building at good detail and of the overall scene, while dropping a huge work of image collection and processing for the textures.Comparisons are investigated with regard to state of the art urban modeling methods, highlighting the differences and possible synergies.