Ambient intelligence platform using multi-agent system and mobile ubiquitous hardware

In this paper, a novel ambient intelligence (AmI) platform is proposed to facilitate fast integration of different control algorithms, device networks and user interfaces. This platform defines the overall hardware/software architecture and communication standards. It consists of four layers, namely the ubiquitous environment, middleware, multi-agent system and application layer. The multi-agent system is implemented using Java Agent DEvelopment (JADE) framework and allows users to incorporate multiple control algorithms as agents for managing different tasks. The Universal Plug and Play (UPnP) device discovery protocol is used as a middleware, which isolates the multi-agent system and physical ubiquitous environment while providing a standard communication channel between the two. An XML content language has been designed to provide standard communication between various user interfaces and the multi-agent system. A mobile ubiquitous setup box is designed to allow fast construction of ubiquitous environments in any physical space. The real time performance analysis shows the potential of the proposed AmI platform to be used in real-life AmI applications. A case study has also been carried out to demonstrate the possibility of integrating multiple control algorithms in the multi-agent system and achieving a significant improvement on the overall offline learning performance.     

A Flexible Architecture for Virtual Humans in Networked Collaborative Virtual Environments

Complex virtual human representation provides more natural interaction and communication among participants in networked virtual environments, hence it is expected to increase the sense of being together within the same virtual world. We present a flexible framework for the integration of virtual humans in networked collaborative virtual environments. A modular architecture allows flexible representation and control of the virtual humans, whether they are controlled by a physical user using all sorts of tracking and other devices, or by an intelligent control program turning them into autonomous actors. The modularity of the system allows for fairly easy extensions and integration with new techniques making it interesting also as a testbed for various domains from “classic” VR to psychological experiments. We present results in terms of functionalities, example applications and measurements of performance and network traffic with an increasing number of participants in the simulation.     

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.     

A causal modelling framework for the simulation and explanation of the behaviour of structures

An approach to the modelling of systems in civil engineering is presented. It allows the integration of quantitative relations in a qualitative causal framework which uses objects and Petri nets to represent the device and process ontologies. This approach supports the modelling and simulation of the behaviour of a physical system and causal explanations of it. The explanations are customisable depending on the needs of different users. The approach is shown by modelling the seismic behaviour of a masonry building, simulating it and generating causal explanations tailored for the needs of different users. An example application is presented through IGOR, a decision support system for seismic assessment of buildings and planning of precautionary operations.     

Magic Touch: A Simple Object Location Tracking System Enabling the Development of Physical-Virtual Artefacts in Office Environments

A novel method for tracking physical activities is presented. The method is based on the assumption that all changes to the physical environment are done by users themselves, and that these actions can be tracked using wearable computer technology placed on human hands. Various limitations of the proposed method are discussed. Acknowledging these limitations, a range of possible applications are presented, e.g. a set of Physical-Virtual Artefacts intended to decrease the gap between the physical and virtual environments within offices. Also, some aspects of the modelling of user actions in office environments are discussed.     

Untethered gesture acquisition and recognition for virtual world manipulation

Humans use a combination of gesture and speech to interact with objects and usually do so more naturally without holding a device or pointer. We present a system that incorporates user body-pose estimation, gesture recognition and speech recognition for interaction in virtual reality environments. We describe a vision-based method for tracking the pose of a user in real time and introduce a technique that provides parameterized gesture recognition. More precisely, we train a support vector classifier to model the boundary of the space of possible gestures, and train Hidden Markov Models (HMM) on specific gestures. Given a sequence, we can find the start and end of various gestures using a support vector classifier, and find gesture likelihoods and parameters with a HMM. A multimodal recognition process is performed using rank-order fusion to merge speech and vision hypotheses. Finally we describe the use of our multimodal framework in a virtual world application that allows users to interact using gestures and speech.     

Storytelling in virtual environments from a virtual guide perspective

This paper describes our proposal for storytelling in virtual environments from a virtual guide perspective, detailing the involved knowledge representation and algorithms. In our model the guide begins at a particular location and starts to navigate the world telling the user stories related to the places she visits. Our guide tries to emulate a real guides behaviour in such a situation. In particular, she behaves as a spontaneous real guide who knows stories about the places in the virtual world but has not prepared an exhaustive tour nor a storyline.     

An overview of physically-based modelling techniques for virtual environments

A class of virtual environments is concerned with the representation of behaviour that is apparent in the real world. In order to model this behaviour, sophisticated physical models are required. The development of these models, classed asphysically-based modelling, is based upon the fundamental concepts of Newtonian dynamics. Considerable research into physically-based modelling has already been conducted by the computer graphics community, permitting realistic animation of object motion. The application of physical models to virtual environments poses further problems, not least that of real-time execution in a fully interactive environment. This paper gives an overview of the existing computer graphics research concerned with physically-based modelling, discussing the merits and problems of various techniques in terms of the requirements of virtual environment.     

Representing older and disabled people in virtual user trials: data collection methods

A database was developed to support the creation of a computer-based tool which will support design teams in evaluating the usability of a design during early prototyping and indicate which individuals are effectively excluded or designed out. Methods are described for the collection of multivariate data on 100 real individuals covering a range of physical characteristics and capabilities. These data were tested to ensure a breadth of representation of individuals (particularly older and disabled people) in terms of anthropometry, joint constraints, postural capabilities and task behaviours. The concept of the design tool itself is explored by conducting virtual user trials in the computer-aided design environment. The novel approach of the research encourages empathy with individual users and allows generic abilities, such as bending, reaching and lifting to be assessed.     

Characteristics and usage patterns of older people in a 3D online multi-user virtual environment

3D online multi-user virtual environments (MUVEs) have a lot of potential in supporting older people in their daily lives, yet little research has been conducted to explore how older people engage with this type of technology. This paper aims to investigate the characteristics, user groups and activity patterns (particularly social networks and gift giving behaviour) of older users within a 3D online multi-user virtual environment. Data from approximately 5000 online user profiles of older and younger users from a 3D MUVE, namely IMVU, was collected for analysis. Overall, we identified several distinct patterns of use (e.g. size of social ties, level of reciprocity, etc.) among older users when compared with younger users. We also found that despite the capabilities of 3D MUVEs to provide the users immersion in alternative realities, a feature well embraced by younger users in this study, older users seemed more interested in activities which serve as an extension to their physical life.     

回旋加速器虚拟控制系统框架设计

回旋加速器虚拟控制系统是用来模拟回旋加速器控制系统,进行控制算法的验证。通过三维模型形象直观的显示系统的运行,为回旋加速器虚拟样机的整机设计提供帮助,从而减少系统硬件实现阶段的修改。该系统采用三层分布式设计结构,最上层为中央控制台和三维显示系统,中间层主要由数据库和仿真程序组成。最下层是回旋加速器的数字模型。系统在LabVIEW、MATLAB、OpenGL和VC环境中初步开发,具有良好的可靠性和可扩展性。     

GBLT-VG for High User Densities by User Group Behavior and Hot Point in MMO Virtual Environment

Massively Multiplayer Online (MMO) games have large-scale virtual environments. Here, we propose a load distribution technique called the Group Based Load-distribution Technique with Virtual Group (GBLT-VG) that utilizes Peer-to-Peer (P2P) communication to maintain scalability under high user density conditions in MMO virtual environments. A common problem of P2P virtual environments is that user group behavior frequently generates high user density conditions. Existing techniques to manage the virtual environment cannot maintain performance in such high user density situations. The proposed technique, GBLT-VG, reduces area management loads of manager peers by introducing a new manager who manages a user neighbor group. GBLT-VG forms the user neighbor group efficiently by using party function under high user density conditions caused by users?? cooperative behaviors. In addition, GBLT-VG reduce the management load by using a virtual group when a number of parties is small, thereby decreasing the existing managers?? loads dynamically. This paper also presents simulation results demonstrating how GBLT-VG can reduce the average number of users managed by the server.     

Tangled reality

Leonardo da Vinci was a strong advocate for using sketches to stimulate the human imagination. Sketching is often considered to be integral to the process of design, providing an open workspace for ideas. For these same reasons, children use sketching as a simple way to express visual ideas. By merging the abstraction of human drawings and the freedom of virtual reality with the tangibility of physical tokens, Tangled Reality creates a rich mixed reality workspace. Tangled Reality allows users to build virtual environments based on simple colored sketches and traverse them using physical vehicles overlayed with virtual imagery. This setup allows the user to “build” and “experience” mixed reality simulations without ever touching a standard computer interface.     

Grasping,communicating, understanding: Connecting reality and virtuality

Several simulation projects in the area of production and logistics indicated that, although we have sophisticated input and output devices for computer supported modelling, physical models still play an important role for cognition and communication. We therefore introduce the concept of a Graspable User Interface that aims at combining two model worlds, the one inside the computer and a corresponding physical one in the outside world. Sensored user hands will couple physical objects of the real world with virtual objects, thus allowing fairly unrestricted manipulation and expression. In this way modelling with real physical objects can create an abstract virtual model. Some applications of this concept are presented. A further perspective for a new action oriented communication and learning with artifacts is envisioned.     

AIR-MODELLING: A tool for gesture-based solid modelling in context during early design stages in AR environments

Augmented reality (AR) technologies are just being used as interface in CAD tools allowing the user to perceive 3D models over a real environment. The influence of the use of AR in the conceptualization of products whose configuration, shape and dimensions depend mainly on the context remains unexplored. We aimed to prove that modelling in AR environments allows to use the context in real-time as an information input for making the iterative design process more efficient. In order to prove that, we developed a tool called AIR-MODELLING in which the designer is able to create virtual conceptual products by hand gestures meanwhile he/she is interacting directly with the real scenario. We conducted a test for comparing designers’ performance using AIR-MODELLING and a traditional CAD system. We obtained an average reduction of 44% on the modeling time in 76% of the cases. We found that modelling in AR environments using the hands as interface allows the designer to quickly and efficiently conceptualize potential solutions using the spatial restrictions of the context as an information input in real-time. Additionally, modelling in a natural scale, directly over the real scene, prevents the designer from drawing his/her attention on dimensional details and allows him/her to focus on the product itself and its relation with the environment.     

Estimation of Detection Thresholds for Redirected Walking Techniques

In immersive virtual environments (IVEs), users can control their virtual viewpoint by moving their tracked head and walking through the real world. Usually, movements in the real world are mapped one-to-one to virtual camera motions. With redirection techniques, the virtual camera is manipulated by applying gains to user motion so that the virtual world moves differently than the real world. Thus, users can walk through large-scale IVEs while physically remaining in a reasonably small workspace. In psychophysical experiments with a two-alternative forced-choice task, we have quantified how much humans can unknowingly be redirected on physical paths that are different from the visually perceived paths. We tested 12 subjects in three different experiments: (E1) discrimination between virtual and physical rotations, (E2) discrimination between virtual and physical straightforward movements, and (E3) discrimination of path curvature. In experiment E1, subjects performed rotations with different gains, and then had to choose whether the visually perceived rotation was smaller or greater than the physical rotation. In experiment E2, subjects chose whether the physical walk was shorter or longer than the visually perceived scaled travel distance. In experiment E3, subjects estimate the path curvature when walking a curved path in the real world while the visual display shows a straight path in the virtual world. Our results show that users can be turned physically about 49 percent more or 20 percent less than the perceived virtual rotation, distances can be downscaled by 14 percent and upscaled by 26 percent, and users can be redirected on a circular arc with a radius greater than 22 m while they believe that they are walking straight.     

Virtual prototyping of automated manufacturing systems with Geometry-driven Petri nets

The design process of automated manufacturing systems typically involves physical prototypes to validate the interactions between hardware and software components. However, physical prototyping is expensive and time consuming, which often leads to insufficient opportunities for testing early during the development cycle. Our objective is to improve this situation by providing a method to develop realistic prototypes using virtual reality technology that can be applied during earlier development stages. Our approach combines a virtual reality engine capable of enacting the laws of rigid body physics with a new hybrid software modelling language to control the simulated hardware using virtual sensors and actuators as they would be present in a physical prototype. The new modelling language is called Geometry-driven Petri nets (GPN) and combines a class of timed, high-level Petri nets with data structures used in state-of-the-art VR environments. This article describes the new GPN approach, applies it to a case study of an automated manufacturing line, and compares it with related approaches.     

From early virtual garment simulation to interactive fashion design

Virtual garment design and simulation involves a combination of a large range of techniques, involving mechanical simulation, collision detection, and user interface techniques for creating garments. Here, we perform an extensive review of the evolution of these techniques made in the last decade to bring virtual garments to the reach of computer applications not only aimed at graphics, but also at CAD techniques for the garment industry.As a result of the advances in the developments of virtual garment simulation technologies, we then detail a framework which fits the needs of the garment industry of virtual garment design and prototyping, concentrating on interactive design, simulation and visualization features. The framework integrates innovative tools aimed towards efficiency and quality in the process of garment design and prototyping, taking advantage of state-of-the-art algorithms from the field of mechanical simulation, animation and rendering.     

基于可视外部力/力矩隐喻工具的虚拟样机动力学交互分析方法

在虚拟样机动力学分析中，对施加的外部力／力矩的属性和作用进行了分析，实现了力／力矩隐喻(metaphor)工具在虚拟环境中的直观定义，并基于多刚体Lagrange动力学模型提出直观驱动的交互仿真方法，建立了可视化隐喻工具同虚拟样机间交互分析过程的动力学广义模型．简化了虚拟环境中用户同虚拟对象间的交互行为模型．最后．通过对汽车发动机曲柄活塞部分建立Lagrange动力学模型．并以建立的隐喻工具进行交互分析的实例论证了该方法的有效性以及隐喻工具的直观性．     

SnakeSIM: a ROS-based control and simulation framework for perception-driven obstacle-aided locomotion of snake robots

Biological snakes are capable of exploiting roughness in the terrain for locomotion. This feature allows them to adapt to different types of environments. Snake robots that can mimic this behaviour could be fitted with sensors and used for transporting tools to hazardous or confined areas that other robots and humans are unable to access. Snake robot locomotion in a cluttered environment where the snake robot utilises a sensory–perceptual system to perceive the surrounding operational environment for means of propulsion can be defined as perception-driven obstacle-aided locomotion (POAL). The initial testing of new control methods for POAL in a physical environment using a real snake robot imposes challenging requirements on both the robot and the test environment in terms of robustness and predictability. This paper introduces SnakeSIM, a virtual rapid-prototyping framework that allows researchers for the design and simulation of POAL more safely, rapidly and efficiently. SnakeSIM is based on the robot operating system (ROS) and it allows for simulating the snake robot model in a virtual environment cluttered with obstacles. The simulated robot can be equipped with different sensors. Tactile perception can be achieved using contact sensors to retrieve forces, torques, contact positions and contact normals. A depth camera can be attached to the snake robot head for visual perception purposes. Furthermore, SnakeSIM allows for exploiting the large variety of robotics sensors that are supported by ROS. The framework can be transparently integrated with a real robot. To demonstrate the potential of SnakeSIM, a possible control approach for POAL is considered as a case study.