An interactive virtual prototyping platform considering environment effect described by fluid dynamics

Virtual prototyping (VP) technology has been regarded as a cost-effective way of envisaging real circumstances that enhance effective communication of designs and ideas, without manufacturing physical samples. Different from recent interactive VPs that are only based on multi-body systems, our VP platform is based on a multi-body coupled with fluid system, that is, the performance and functions of a VP will not be independent of environment factors or disturbances but interact with each other and constitute a whole system. Using this platform designers can simulate a robot through vacuum, air, water environments, etc., so it can provide a better support to the generality and quality of a VP. As for interactive manipulation, designers can modify the constraints between bodies, apply force/torque to interested bodies and change the parameters of forces/torques. Corresponding to user interaction, the platform automatically updates the dynamic behavior of the VP under current condition in the simulation loop. Furthermore, we implemented a virtual MiniBaja vehicle to verify the interactivity and effectiveness of this platform.     

Coupling dynamic simulation and interactive multiobjective optimization for complex problems: An APROS-NIMBUS case study

Dynamic process simulators for plant-wide process simulation and multiobjective optimization tools can be used by industries as a means to cut costs and enhance profitability. Specifically, dynamic process simulators are useful in the process plant design phase, as they provide several benefits such as savings in time and costs. On the other hand, multiobjective optimization tools are useful in obtaining the best possible process designs when multiple conflicting objectives are to be optimized simultaneously. Here we concentrate on interactive multiobjective optimization. When multiobjective optimization methods are used in process design, they need an access to dynamic process simulators, hence it is desirable for them to coexist on the same software platform. However, such a co-existence is not common. Hence, users need to couple multiobjective optimization software and simulators, which may not be trivial. In this paper, we consider APROS, a dynamic process simulator and couple it with IND-NIMBUS, an interactive multiobjective optimization software. Specifically, we: (a) study the coupling of interactive multiobjective optimization with a dynamic process simulator; (b) bring out the importance of utilizing interactive multiobjective optimization; (c) propose an augmented interactive multiobjective optimization algorithm; and (d) apply an APROS-NIMBUS coupling for solving a dynamic optimization problem in a two-stage separation process.     

Developing Multimodal Adaptation Algorithm for Mobility Impaired Users by Evaluating Their Hand Strength

Recent research on interactive electronic systems like computer, digital TV, smartphones can improve the quality of life of many disabled and elderly people by helping them to engage more fully to the world. Previously, a simulator was developed that reflects the effect of impairment on interaction with electronic devices and thus helps designers in developing accessible systems. In this article, the scope of the simulator has been extended to multiple pointing devices. The way that hand strength affects pointing performance of people with and without mobility impairment in graphical user interfaces was investigated for four different input modalities, and a set of linear equations to predict pointing time and average number of submovements for different devices was developed. These models were used to develop an adaptation algorithm to facilitate pointing in electronic interfaces by users with motor impairment using different pointing devices. The algorithm attracts a pointer when it is near a target and thus helps to reduce random movement during homing and clicking. The algorithm was optimized using the simulator and then tested on a real-life application with multiple distractors involving three different pointing devices. The algorithm significantly reduces pointing time for different input modalities.     

Haptic‐constraint modeling based on interactive metaballs

Adding interactive haptic‐constraint sensations is important in interactive computer gaming and 3D shape design. Usually constraints are set on vertices of the object to drive the deformation. How to simulate dynamic force constraints in interactive design is still a challenging task. In this paper, we propose a novel haptic‐constraint modeling method based on interactive metaballs, during which the haptic‐constraint tools are attracted to the target location and then control the touch‐enabled deformation within the constrained areas. The interactive force feedbacks facilitate designers to accurately deform the target regions and fine carve the details as their intention on the objects. Our work studies how to apply touch sensation in such constrained deformations using interactive metaballs, thus users can truly feel and control the soft‐touch objects during the deforming interactions. Experimental results show that the dynamic sense of touch during the haptic manipulation is intuitively simulated to users, via the interacting interface we have developed. Copyright © 2010 John Wiley & Sons, Ltd.     

20-sim software for hierarchical bond-graph/block-diagram models

We discuss the modeling and simulation package 20-sim, a tool for modeling and simulation of dynamic behavior of engineering systems. Engineering systems as application domain means that we focus on systems that span multiple physical domains and the information domain. The 20-sim software is an interactive tool, where model entry and model processing are fully integrated. This means that already during model entry and editing, models can be checked on their consistency. 20-sim has its own simulator, using sophisticated numerical integration methods, taken from. internationally accepted numerical libraries. The use of 20-sim is demonstrated by an example, in which a 3-dof scara robot with controller is modeled and simulated.     

IFAS: Interactive flexible ad hoc simulator

Ad hoc networks are characterized by fast, dynamic changes in the topology of the network. Introduction of new routing algorithms requires a deep and reliable evaluation process. In this paper, we describe an interactive flexible ad hoc simulator (IFAS) that presents a modern and novel approach to the family of ad hoc simulators. This simulator supports unique viewing, debugging, tuning and interactive capabilities that shorten significantly the design and debug process of new algorithms. The development of the IFAS is ongoing; however, we consider this new simulator as an innovative tool that will supplement traditional simulators.     

Touch-enabled haptic modeling of deformable multi-resolution surfaces

Currently, interactive data exploration in virtual environments is mainly focused on vision-based and non-contact sensory channels such as visual/auditory displays. The lack of tactile sensation in virtual environments removes an important source of information to be delivered to the users. In this paper, we propose the touch-enabled haptic modeling of deformable multi-resolution surfaces in real time. The 6-DOF haptic manipulation is based on a dynamic model of Loop surfaces, where the dynamic parameters are computed easily without subdividing the control mesh recursively. A local deforming scheme is developed to approximate the solution of the dynamics equations, thus the order of the linear equations is reduced greatly. During each of the haptic interaction loop, the contact point is traced and reflected to the rendering of updated graphics and haptics. The sense of touch against the deforming surface is calculated according to the surface properties and the damping-spring force profile. Our haptic system supports the dynamic modeling of deformable Loop surfaces intuitively through the touch-enabled interactive manipulation.     

Dynamic interactions in physically realistic collaborative virtual environments

This work describes our efforts in creating a general object interaction framework for dynamic collaborative virtual environments. Furthermore, we increase the realism of the interactive world by using a rigid body simulator to calculate all actor and object movements. The main idea behind our interactive platform is to construct a virtual world using only objects that contain their own interaction information. As a result, the object interactions are application independent and only a single scheme is required to handle all interactions in the virtual world. In order to have more dynamic interactions, we also created a new and efficient way for human users to dynamically interact within virtual worlds through their avatar. In particular, we show how inverse kinematics can be used to increase the interaction possibilities and realism in collaborative virtual environments. This results in a higher feeling of presence for connected users and allows for easy, on-the-fly creation of new interactions. For the distribution of both the interactive objects and the dynamic avatar interactions, we keep the network load as low as possible. To demonstrate the effectiveness of our techniques, we incorporate them into an existing CVE framework.     

基于Mechanism/Pro的汽车悬架系统运动仿真

为了解决多体动力学分析仿真过程中困扰仿真人员的模型建立和修改问题,以汽车独立悬架为研究对象,提出机械系统仿真一种比较理想的方法.首先应用多体动力学求解理论,从悬架物理模型中提取多体动力学求解模型.针对ADAMS/View建模能力较弱,通过三维建模软件Pro/E建模,采用Mechanism/Pro模块定义刚体、添加约束和驱动、调用ADAMS/Solver求解.可以很方便地建立复杂机械系统模型,并根据仿真结果及时对模型进行修改,实现机械系统多体动力学仿真的前处理、求解以及后处理均集成在Pro/E环境中.     

DYNAMIC DISPLAY OF PERSONALIZED SOFTWARE FUNCTIONS

Generalized software packages endowed with a large spectrum of functionalities are often underutilized because users are not always aware of all the functionalities. It is hence desirable to display personalized information about the package. Though popular in web-based applications, personalization as a field of research in the design of generalized software packages is rare. This article develops a semi-Markov model of user navigation and an adaptive dynamic programming formulation to select high-utility software functions (states) for dynamically displaying them to a user. The personalization algorithm considers the interests of the software designers, the past users, and the current user. Frequency of visit to a state and the holding time in the state together determines the utility of the state. The personalization algorithm considers the interests of the software designers, the past users, and the current user. The algorithm is built in a demo package of ActiveX Servers and Controls. Graduate students tested the package. Pareto analysis and tests of hypothesis conducted on the test results indicate that the users did utilize the information on the displayed personalized software functions.     

Parallel use of hand gestures and force‐input device for interacting with 3d and virtual reality environments

User interfaces of current 3D and virtual reality environments require highly interactive input/output (I/O) techniques and appropriate input devices, providing users with natural and intuitive ways of interacting. This paper presents an interaction model, some techniques, and some ways of using novel input devices for 3D user interfaces. The interaction model is based on a tool‐object syntax, where the interaction structure syntactically simulates an action sequence typical of a human's everyday life: One picks up a tool and then uses it on an object. Instead of using a conventional mouse, actions are input through two novel input devices, a hand‐ and a force‐input device. The devices can be used simultaneously or in sequence, and the information they convey can be processed in a combined or in an independent way by the system. The use of a hand‐input device allows the recognition of static poses and dynamic gestures performed by a user's hand. Hand gestures are used for selecting, or acting as, tools and for manipulating graphical objects. A system for teaching and recognizing dynamic gestures, and for providing graphical feedback for them, is described.     

How to model and prove hybrid systems with KeYmaera: a tutorial on safety

This paper is a tutorial on how to model hybrid systems as hybrid programs in differential dynamic logic and how to prove complex properties about these complex hybrid systems in KeYmaera, an automatic and interactive formal verification tool for hybrid systems. Hybrid systems can model highly nontrivial controllers of physical plants, whose behaviors are often safety critical such as trains, cars, airplanes, or medical devices. Formal methods can help design systems that work correctly. This paper illustrates how KeYmaera can be used to systematically model, validate, and verify hybrid systems. We develop tutorial examples that illustrate challenges arising in many real-world systems. In the context of this tutorial, we identify the impact that modeling decisions have on the suitability of the model for verification purposes. We show how the interactive features of KeYmaera can help users understand their system designs better and prove complex properties for which the automatic prover of KeYmaera still takes an impractical amount of time. We hope this paper is a helpful resource for designers of embedded and cyber–physical systems and that it illustrates how to master common practical challenges in hybrid systems verification.     

A case study of intended versus actual experience of adaptivity in a tangible storytelling system

This article presents a case study of an adaptive, tangible storytelling system called “The Reading Glove”. The research addresses a gap in the field of adaptivity for ubiquitous systems by taking a critical look at the notion of “adaptivity” and how users experience it. The Reading Glove is an interactive storytelling system featuring a wearable, glove-based interface and a set of narratively rich objects. A tabletop display provides adaptive recommendations which highlight objects to select next, functioning as an expert storytelling system. The recommendation engine can be run in three different configurations to examine the effects of different adaptive methods. The study of the design process as well as the user experience of the Reading Glove allows us to develop a deeper understanding of the experience of adaptivity that is useful for designers of intelligent systems, particularly those with ubiquitous and tangible forms of interaction.     

基于MFC和OpenGL的虚拟人体经络穴位模型实现方法

现有人体经络穴位模型较少具有触摸交互功能,本文基于OpenGL(Open Graphics Library)和MFC(Microsoft Foundation Classes)技术框架,仿真实现交互式虚拟人体经络穴位模型系统,并介绍其实现方法和过程。首先建立人体模型以及穴位点、经络线段。然后利用OpenGL和MFC对模型、穴位点、经络线加载和渲染。详细阐述系统实现的框架和流程,以及在开发过程中涉及的关键技术,如使用动态方向调整来显示穴位点名称,使用全局函数传递消息来提高模型加载响应的效率,给出触摸点坐标快速获取的方法。最后将模型成功部署到触摸式一体机上。模型系统具有较好的交互性,无需鼠标,仅用手指触摸即能实现模型的放大、缩小、旋转、定穴、经络循环等操作。模型能够帮助使用者学习经络知识,其穴位记忆功能能够测试使用者对穴位掌握情况,也为穴位爱好者提供较真实的经络穴位学习环境。     

Interaction model between elastic objects for haptic feedback considering collisions of soft tissue

The simulation of organ–organ interaction is indispensable for practical and advanced medical VR simulator such as open surgery and indirect palpation. This paper describes a method to represent real-time interaction between elastic objects for accurate force feedback in medical VR simulation. The proposed model defines boundary deformation of colliding elements based on temporary surface forces calculated by temporary deformation. The model produces accurate deformation and force feedback considering collisions of objects as well as prevents unrealistic overlap of objects. A prototype simulator of rectal palpation is constructed on general desktop PC with a haptic device, PHANToM. The system allows users to feel different stiffness of a rear elastic object located behind another elastic object. The results of experiments confirmed the method expresses organ–organ interaction in real-time and produces realistic and perceivable force feedback.     

基于反馈的交互式动态GIS景观评价模型

提出一种基于反馈的交互式动态GIS景观评价模型,并指出该模型与4D-GIS模型相比较的优点.该评价模型充分考虑景观的动态性,在规划中同时加入了景观规划设计师的交互行为和规划系统本身的交互功能.利用系统本身的交互能力提供的反馈功能,规划人员可以对景观评价系统进行实时控制和修正,以达到更好的景观规划效果.最后通过一个实例简要说明了应用基于该模型的景观评价系统进行规划设计的通用流程.     

DENIM: An Informal Web Site Design Tool Inspired by Observations of Practice

Through a study of Web site design practice, we observed that designers employ multiple representations of Web sites as they progress through the design process and that these representations allow them to focus on different aspects of the design. In particular, we observed that Web site designers focus their design efforts at 3 different levels of granularity-site map, storyboard, and individual page-and that designers sketch at all levels during the early stages of design. Sketching on paper is especially important during the early phases of a project, when designers wish to explore many design possibilities quickly without focusing on low-level details. Existing Web design tools do not support such exploration tasks well, nor do they adequately integrate multiple site representations. Informed by these observations we developed DENIM: an informal Web site design tool that supports early phase information and navigation design of Web sites. It supports sketching input, allows design at different levels of granularity, and unifies the levels through zooming. Designers are able to interact with their sketched designs as if in a Web browser, thus allowing rapid creation and exploration of interactive prototypes. Based on an evaluation with professional designers as well as usage feedback from users who have downloaded DENIM from the Internet, we have made numerous improvements to the system and have received many positive reactions from designers who would like to use a system like DENIM in their work.     

Real‐time haptic manipulation and cutting of hybrid soft tissue models by extended position‐based dynamics

This paper systematically describes an interactive dissection approach for hybrid soft tissue models governed by extended position‐based dynamics. Our framework makes use of a hybrid geometric model comprising both surface and volumetric meshes. The fine surface triangular mesh with high‐precision geometric structure and texture at the detailed level is employed to represent the exterior structure of soft tissue models. Meanwhile, the interior structure of soft tissues is constructed by coarser tetrahedral mesh, which is also employed as physical model participating in dynamic simulation. The less details of interior structure can effectively reduce the computational cost during simulation. For physical deformation, we design and implement an extended position‐based dynamics approach that supports topology modification and material heterogeneities of soft tissue. Besides stretching and volume conservation constraints, it enforces the energy preserving constraints, which take the different spring stiffness of material into account and improve the visual performance of soft tissue deformation. Furthermore, we develop mechanical modeling of dissection behavior and analyze the system stability. The experimental results have shown that our approach affords real‐time and robust cutting without sacrificing realistic visual performance. Our novel dissection technique has already been integrated into a virtual reality‐based laparoscopic surgery simulator. Copyright © 2015 John Wiley & Sons, Ltd.     

控制对象仿真系统的研究

用系统工程的分析方法建立了一系列常见的动态仿真模型。模型包括动态画面制作、对象参数的设定、脚本程序的编制、通信程序的编写及参数设置等内容，达到了动态模拟真实被控对象的效果。该仿真系统用VB语言开发并在Windows环境下运行，它为可编程序控制器的教学与培训提供了一套较为丰富、灵活的虚拟被控对象，利用它可以设置一些异常情况，以训练和提高操作员的编程技能和解决突发事故的能力。此外，该模型作为一种有效的训练手段可以大大节省培训设备的投资。