基于HLA的多agent虚拟环境表现机制

高层体系结构（HLA）是美国国防部提出的新一代仿真技术框架,它具有高度的互操作性和可重用性。为大规模、分布式的具有复杂交互行为的多agent虚拟环境提供了良好的底层框架。本文针对基于HLA／RTI规范的多agent虚拟战场环境（MAVE－HLA）,提出了基于层次结构的动态实体的多媒体表现框架和相应的行为表现机制,它支持可重用、可扩展,同时实时性和交互性易于实现。     

A declarative approach to procedural modeling of virtual worlds

With the ever increasing costs of manual content creation for virtual worlds, the potential of creating it automatically becomes too attractive to ignore. However, for most designers, traditional procedural content generation methods are complex and unintuitive to use, hard to control, and generated results are not easily integrated into a complete and consistent virtual world.We introduce a novel declarative modeling approach that enables designers to concentrate on stating what they want to create instead of on describing how they should model it. It aims at reducing the complexity of virtual world modeling by combining the strengths of semantics-based modeling with manual and procedural approaches. This article describes two of its main contributions to procedural modeling of virtual worlds: interactive procedural sketching and virtual world consistency maintenance. We discuss how these techniques, integrated in our modeling framework SketchaWorld, build up to enable designers to create a complete 3D virtual world in minutes. Procedural sketching provides a fast and more intuitive way to model virtual worlds, by letting designers interactively sketch their virtual world using high-level terrain features, which are then procedurally expanded using a variety of integrated procedural methods. Consistency maintenance guarantees that the semantics of all terrain features is preserved throughout the modeling process. In particular, it automatically solves conflicts possibly emerging from interactions between terrain features.We believe that these contributions together represent a significant step towards providing more user control and flexibility in procedural modeling of virtual worlds. It can therefore be expected that by further reducing its complexity, virtual world modeling will become accessible to an increasingly broad group of users.     

VDVAS：一个集成的虚拟设计与虚拟装配系统

随着虚拟现实技术的逐渐成熟，研究者们已将其引入到工程领域，为实现虚拟设计与虚拟装配过程的集成，避免现有的虚拟装配系统中，虚拟环境与CAD系统间所必需进行的复杂的、无谓的数据传输，描述了一个基于多通道的、集成的虚拟设计与虚拟装配系统VDVAS。在该系统中，设计得可以通过直接三维操作和语音命令直观方便地建立机械零件及其装配模型，并通过交互拆装来得到零件的装配顺序和装配路径等信息，VDVAS的一个重要特征在于，可通过集成虚拟设计与虚拟装配过程，使设计者能在一个集成的虚拟环境中修改零件几何（假如在装配过程中发现零件存在设计缺陷的话）。     

具有协同交流功能的虚拟物理实验室

为解决虚拟实验中师生不能有效交流的问题,采用VRML-JS-Java通信机制实现了一种具有交流功能的虚拟物理实验室.介绍了实验室总体设计和场景层次结构,阐述了三维场景的建模过程和流程,重点对交互功能的服务器端、客户端、用户间的交互与感知,以及VRML虚拟场景与Java接口等关键技术进行实现.经过发布与测试,表明虚拟物理实验室具有良好的层次性、可重用性和互操作性,在大学实验教学改革中具有较高的实用价值.     

Manipulating Objects in Virtual Worlds: Categorization and Empirical Evaluation of Interaction Techniques

The acceptance of virtual environment (VE) technology requires scrupulous optimization of the most basic interactions to maximize user performance and provide efficient and enjoyable virtual interfaces. Motivated by insufficient understanding of human factors implications in the design of interaction techniques for object manipulation in virtual worlds, this paper presents results of a formal study that evaluated two basic interaction metaphors for virtual manipulation—virtual pointer and virtual hand—in object selection and positioning tasks. In this work, we survey and categorize current virtual manipulation techniques according to their basic design metaphors, conduct experimental studies of the most basic techniques, and derive guidelines to aid designers in the practical development of VE applications.     

A simulation modelling tool for Distributed Virtual Environments

Distributed Virtual Environments simulate the behaviour and activities of a great number of users interacting in a virtual world over a wide area network. The size of the virtual worlds and the tremendous number of users that these environments are called to support require additional bandwidth and computational resources. For supporting large-scale Distributed Virtual Environments, extended infrastructure is needed in terms of both hardware and software. However, both researchers and application designers do not always have access to such an extended infrastructure and the assessment and evaluation of developed performance improvement techniques becomes extremely difficult. To address this issue, this paper presents a simulation modelling tool, called STEADiVE for networked servers Distributed Virtual Environments that could be used by designers for evaluating the performance of their approaches under different scenarios and system settings. The validation of the simulation modelling tool has showed that it achieves high accuracy in representing a real DVE system. STEADiVE comes to fill in the gap in the area of simulation tools for these systems.     

Increasing student engagement through virtual interactions: How?

Our ongoing research is focusing on identifying and taxonomising the elements and the factors that affect learner engagement with virtual worlds when hybrid virtual learning models are used. Our main hypothesis links learner engagement with interactions, both in the virtual world and in the physical classroom. In order to examine this subject, there is an elaboration on and consideration of aspects such as the learners’ prior experiences in the use of virtual worlds, their preconceptions about using them as a learning tool and the impact that the instructional designers’ choices have on enhancing the opportunities for interactions. In this paper, we examine the impact that the orientation process has on university students who study computer science and have almost no experience in the use of virtual worlds. Our findings suggest that the orientation process contributed positively to students’ smooth induction and that resulted in having meaningful and engaging interactions. Furthermore, students’ simultaneous coexistence in both environments eliminated the drawbacks of each educational approach and broadened the network of interactions.     

Virtual world teaching,experiential learning,and assessment: An interdisciplinary communication course in Second Life

While many reports espouse the potential impact that 3-D virtual worlds are expected to have on teaching and learning in higher education in a few years, there are few empirical studies that inform instructional design and learning assessment in virtual worlds. This study explores the nature and process of learning in Second Life in a graduate interdisciplinary communication course in fall 2007. Literature suggests that 3-D virtual worlds can be well suited for experiential learning environments. In this study, the actual instructional effectiveness of Second Life as an experiential learning environment for interdisciplinary communication is empirically examined using mixed research methods of journal content analysis, surveys, focus group, and virtual world snapshots and video.     

Dwelling in Second Life? A phenomenological evaluation of online virtual worlds

In previous research on virtual worlds, the question of whether virtual space can be evaluated just like “real world” space has not been fully addressed. This paper challenges the perceived commonsensical set of assumptions through which virtual world activities are usually unpacked and proposes a new method of evaluating virtual worlds based on Martin Heidegger’s phenomenology. Various focus groups conducted in the virtual world Second Life confirmed that a phenomenological paradigm is more appropriate to fully make sense of and leverage this new medium. Besides questioning the relevancy of dealing with virtual worlds as if they were parallel spaces, this paper, by leveraging a new conceptualization of virtual worlds, also offers suggestions for new online qualitative methodologies.     

Virtual Worlds: A New Reality for Treating Post-Traumatic Stress Disorder

Science does not follow a linear path. Yet, persistence counts in research, and that's the case with virtual worlds. In the 1990s, many people perceived virtual worlds as a fad. Researchers and developers had to wait until innovations in networking, computer graphics, and haptics made the basic elements of VR inexpensive and ubiquitous. The Nintendo Wii is a great example of how technology has progressed in 15 years, with 100 times the performance and 1/100 the cost of high-end workstations from the '90s. Suddenly, a new virtual world is appearing on the Internet each week. Just as suddenly, many researchers can afford to expose many people to the technology, test hypotheses, and explore new problems. Modern society's problems aren't linear either and can appear almost from nowhere. In the 1980s, HIV caused governments everywhere to respond with huge new research programs, which are having an impact. Today's challenge is almost as pernicious because identifying and treating it is difficult - and its cost to society can be just as devastating. That challenge is post-traumatic stress disorder (PTSD), and the science of virtual worlds might well be a major factor in meeting it.     

Scaling Virtual Worlds with a Physical Metaphor

Online virtual worlds have long been an anticipated medium for digital communications. They provide a compelling substrate for shared, networked environments where people can communicate, shop, socialize, collaborate, and learn. However, today's systems fall short of their imagined potential. The Meru project is designing and implementing an architecture for virtual worlds of the future. Our key insight is that a virtual model of the real world is a comfortable metaphor which addresses a wide range of issues including security, scalability, and federation. This symmetry between real and virtual worlds also permits a natural interaction between the two.     

可定制的虚拟展厅

虚拟展厅具有信息容量大、多向演示、模拟生动、身临其境等优势,被广泛应用于展示、宣传、教育等领域。针对目前虚拟展厅改动困难,可重用性、通用性差的缺点,提出一种新的设计思路,将展厅设计为用户可定制,为用户配置展厅模型、展品和说明信息等留出接口,根据用户的参数设定和手动调整生成虚拟展厅。首先分析系统的功能需求,并给出对应的模块划分,从底层、中层、高层对系统进行说明;然后阐明系统的设计思路和总体框架以及遇到的技术难题和解决方案,用户可以根据自己的意愿对展厅进行调整而不需要改动程序。系统增加了虚拟展厅的通用性和可重用性,有利于虚拟展厅的推广和发展。     

A reference architecture for social robots

Social robotics poses tough challenges to software designers who are required to take care of difficult architectural drivers like acceptability, trust of robots as well as to guarantee that robots establish a personalized interaction with their users. Moreover, in this context recurrent software design issues such as ensuring interoperability, improving reusability and customizability of software components also arise. Designing and implementing social robotic software architectures is a time-intensive activity requiring multi-disciplinary expertise: this makes it difficult to rapidly develop, customize, and personalize robotic solutions. These challenges may be mitigated at design time by choosing certain architectural styles, implementing specific architectural patterns and using particular technologies. Leveraging on our experience in the MARIO project, in this paper we propose a series of principles that social robots may benefit from. These principles lay also the foundations for the design of a reference software architecture for social robots. The goal of this work is twofold: (i) Establishing a reference architecture whose components are unambiguously characterized by an ontology thus allowing to easily reuse them in order to implement and personalize social robots; (ii) Introducing a series of standardized software components for social robots architecture (mostly relying on ontologies and semantic technologies) to enhance interoperability, to improve explainability, and to favor rapid prototyping.     

Cognitive revolution, virtuality and good life

We are living in an era when the focus of human relationships with the world is shifting from execution and physical impact to control and cognitive/informational interaction. This emerging, increasingly informational world is our new ecology, an infosphere that presents the grounds for a cognitive revolution based on interactions in networks of biological and artificial, intelligent agents. After the industrial revolution, which extended the human body through mechanical machinery, the cognitive revolution extends the human mind/cognition through information-processing machinery. These novel circumstances come with new qualities and preferences demanding new conceptualizations. We have some work ahead of us to establish value systems and practices extended from the real to the increasingly virtual/info-computational. This paper first presents a current view of the virtual versus the real and then offers an interpretation framework based on an info-computational understanding of cognition in which agency implies computational processing of informational structures of the world as an infosphere. The notion of “good life” is discussed in light of different ideals of well-being in the infosphere, connecting virtuality as a space of potential and alternative worlds for an agent for whom the reality is a space of actual experiences, in the sense of Deleuze. Even though info-computational framework enables us to see both the real world and the diversity of virtual worlds in terms of computational processes on informational structures, based on a distinct layered cognitive architecture of all physical agents, there is clear difference between potential worlds of the virtual and actual agent’s experiences made in the real. Info-computationalism enables insight into the mechanisms of infosphere and elucidates its importance as cognitively predominant environment and communication media. The conclusion is that by cocooning ourselves in an elaborate info-computational infrastructure of the virtual, we may be increasingly isolating ourselves from the reality of direct experience of the world. The biggest challenges of the cognitive revolution may not be technological but ethical. They are about the nature of being human and its values.     

VWRAP for Virtual Worlds Interoperability

The IETF has chartered a Virtual World Region Agent Protocol Working Group (VWRAP WG). This article briefly describes the history of virtual worlds, the architecture, protocols, and operation of Second Life (a currently prominent virtual world), and the emergence of standards efforts within the virtual world space. The authors detail the current efforts and timeline of the VWRAP WG.     

A domain-oriented end-user design environment for generating interactive 3D virtual chemistry experiments

Three-dimensional virtual worlds are potentially feasible for building virtual educational environments. However, educators face technical challenges to apply these technologies because creating virtual educational environments based on virtual worlds demands 3D modeling and programming skills. This paper proposes a method to lower the technical barriers through domain-oriented interfaces with languages and environments that are familiar to educators. A domain-oriented end-user design environment, iVirtualWorld, is designed and developed to implement the proposed method in a specific educational domain, namely introductory chemistry experiments. This web-based environment provides end-users with domain-oriented building blocks, which can be assembled to create 3D virtual chemistry experiments. A usability evaluation and a comparative case study are designed to evaluate the system among chemistry educators, who are the target audience. The usability evaluation contains a task requiring participants to create a 3D virtual chemistry experiment and a voluntary semi-structured interview. The case study compares a virtual experiment generated using iVirtualWorld with an experiment in a commercial virtual chemistry laboratory system. The results show that 1) the domain-oriented end-user design environment enables participants to generate the 3D virtual chemistry experiment within 30 min; 2) participants gain confidence on creating 3D virtual experiments by themselves using iVirtualWorld; 3) participants confirm the usefulness of applying the system in introductory chemistry education; and 4) iVirtualWorld is considered more intuitive and straightforward for students to focus on finishing the experiment without being distracted than the commercial virtual chemistry laboratory system. Areas that can benefit from the system most and areas where the system is less effective are identified by participants. The responses also reveal the limitations of the current system and suggest directions for future improvement.     

Virtual goods,real goals: Exploring means-end goal structures of consumers in social virtual worlds

The aim of this study is to understand consumer goals for virtual consumption in social virtual worlds. Using a means-end chain approach, interviews with 93 users were analyzed to produce a hierarchical goal map, revealing that virtual consumption enables a diversity of goals beyond the previously identified experiential goals. The article's theoretical contributions include: (1) extending our understanding of user goals/goal relationships for virtual activities and (2) developing virtual liminoid theory, which describes transitions between users’ real-world and virtual identities and virtual consumption as a transition catalyst. The study illustrates the value of a goal focus for future research on user behavior in virtual worlds.