WSC 2005 Final Abstracts

Visualization of Construction Graphics in Outdoor Augmented Reality
Amir H. Behzadan and Vineet R. Kamat (University of Michigan)

Abstract:
This paper describes research that investigates the application of Augmented Reality (AR) in 3D animation of simulated construction operations. The objective is an AR-based platform that can be used together with corresponding equipment (HMD, GPS receiver, and a portable computer) to generate a mixed view of the real world and superimposed virtual simulation objects in an outdoor environment. The characteristic that distinguishes the presented work from indoor AR applications is the capability to produce real time updated output as the user moves around while applying minimum constraints over the user’s position and orientation. The ability to operate independently of environmental factors (e.g. lighting conditions and terrain variations) makes the described framework a powerful tool for outdoor AR applications. This paper presents initial results and an AR platform prototype (UM-AR-GPS-ROVER) that is able to place 3D graphical objects at any desired location in outdoor augmented space.

Multi-User Support and Motion Planning of Humans and Humans Driven Vehicles in Interactive 3D Material Flow Simulations
Matthias Fischer and Bengt Mueck (Heinz Nixdorf Institut, University of Paderborn), Kiran Mahajan (University of Paderborn) and Michael Kortenjan, Christoph Laroque, and Wilhelm Dangelmaier (Heinz Nixdorf Institut, University of Paderborn)

Abstract:
The visualization of simulated production processes is used for their analysis. Huge plants are normally planned by a team. So a solution for many users who are modeling and interacting with a running model in an immersive 3D environment is required. We discuss an approach where several users work cooperatively on one simulation model. To optimize their work, the users need some guidance. For this we suggest small maps and arrows to guide the user to significant objects (machines). In many production scenarios, objects (forklifts, workers) are moving in an unguided fashion. In actual implementations these paths have to be modeled manually. In spite of taking these efforts, we are presenting an automated approach which is based on the 3D layout of the plant. If the user as part of the simulation is standing in the way of the object, the object stops in our approach (as hopefully in reality).

Programming Using Dynamic System Modeling via a 3D-Based Multimodeling Framework
Hyunju Shim and Paul Fishwick (University of Florida)

Abstract:
We propose a new approach to visual programming which adopts principles and elements from dynamic multimodeling for structured procedural programming, especially graphics programming. Unlike most traditional visual programming languages which simply replace syntactic parts of program with graphical objects, we applied the principles of dynamic model types in modeling and simulation to create program models and execute/simulate them. With this approach, computer programs are constructed by visual modeling instead of textual writing. The motivation for a method using dynamic model types in graphics programming is also tied to several emerging research areas: novice user interfaces, programming visualization, customized icons, and a broader view of aesthetics within programming. Metaphoric icons are extensively used for the visual representation of program model elements. Rube, a Web- and XML-based modeling and simulation framework, provides the necessary environment for the construction, visualization and execution of program models.

A Two-tier Method for Evaluating Alternative Policies to Support Interactive Analysis of 3D Material Flow Simulations
Wilhelm Dangelmaier, Kiran Mahajan, Daniel Huber, and Bengt Mueck (University of Paderborn)

Abstract:
Discrete-event material flow simulation tools have long been offering real-time 3D visualization. This feature allows less experienced users to analyze the underlying system. Beyond this, visualization is not used to interact with the simulated (underlying manufacturing) system to improve or control the material flow, especially under disturbances. This paper presents a simulation based 2-tier framework, which seeks to control or improve material flow by means of real-time user immersive visualization. The first tier uses static optimization to compute the material flow by selecting from a large number of alternative policies. The second tier is a reactive algorithm which computes solutions for probabilistic disturbances. The results of the two tiers are used for interacting with the underlying system using visualization. We show that the proposed system is able to handle complex alternative policies, which supports interactive analysis of 3D material flow simulations.

Temporally Parallel Coupling of Discrete Simulation Systems with Virtual Reality Systems
Steffen Strassburger (Fraunhofer Institute for Factory Operation and Automation), Thomas Schulze (University of Magdeburg (FIN/ITI)) and Marco Lemessi and Gordon D. Rehn (Deere & Co.)

Abstract:
The coupling of commercial discrete simulation systems with virtual reality (VR) systems opens new possibilities for the temporal interplay of product and process design. Among the possibilities is establishing virtual training centers aimed at shortening product ramp-up times. Up to now, coupling has only been employed sporadically because of the need to preserve the autonomy of the tools used. This paper focuses on the problems of synchronization as one of the important basic tasks when coupling dis-crete simulation and VR systems. Existing techniques of synchronization are examined for their suitability for coupling and a method of synchronization based on self-adapting buffer sizes is described.

Introducing Virtual Engineering Technology Into Interactive Design Process with High-fidelity Models
Gengxun Huang and Kenneth Mark Bryden (Iowa State University)

Abstract:
Product design is a complex decision-making process requiring intense interaction between designers and the designed product. Consequently, the design process is significantly different from a pure mathematical optimization. This paper presents a decision support platform for interactive design that integrates mathematical optimization with human interaction based on VE-Suite. Current efforts are geared toward seamlessly linking high fidelity models, numerical optimization and human interaction to improve efficiency and quality in system performance. The designer’s interaction causes the optimization process to dynamically change by adding, deleting, and modifying objectives, constraints, and other parameters that govern the process. As an illustration, a coal pipe design case is used to demonstrate the new platform’s capabilities. The case has demonstrated that adding user interaction into the design process has the potential to improve design efficiency and quality.

Experimental Investigation of the Impacts of Virtual Reality on Discrete-Event Simulation
Justice I. Akpan and Roger J. Brooks (Lancaster University Management School)

Abstract:
This paper presents the results of experimental studies that were undertaken to test the impacts of Virtual Reality (VR) on Discrete-Event Simulation (DES). The experiments focused on spotting errors in the DES model. The models were developed in 2D and 3D/VR displays using WITNESS. The 2D display used icons and other visualization techniques that confine its scope to essentially flat 2D surface. On the other hand, the 3D display was represented by means of a three-axis spatial position (XYZ) plots, but appeared on a two-dimensionally mappings, otherwise known as 2.5D. The experiments involved paid participants who were recruited from amongst the staff and students of Lancaster University, UK. The results showed that it is easier, and faster to spot errors in 3D/VR model than in 2D. The findings also indicated that users can easily understand the modeled operation of 3D/VR display compared to 2D, irrespective of background or technical ability.

Practitioners’ Perception of the Impacts of Virtual Reality on Discrete-event Simulation
Justice I. Akpan and Roger J. Brooks (Lancaster University Management School)

Abstract:
This paper presents the results from surveying simulation practitioners from industry and academics who have used 2D or 3D software applications for Discrete-Event Simulation (DES) projects. The survey focused on the impacts of Virtual Reality (VR) on DES activities. The findings indicate the software used, the applications areas, the stages in the simulation modeling process where Visual Display is commonly used, and a comparative evaluation of the benefits and costs associated with modeling in 3D over 2D. Other results indicate possible influence of each of the two displays on simulation results, effects on users’ understanding of the modeled system and any corresponding influence on decision-making. The findings also incorporate the pitfalls to avoid when modeling in 3D, and speculations about the future of VR-based DES (VRSIM) practice.

Common Scene Definition Framework for Constructing Virtual Worlds
Lee A. Belfore II, Prabhu V. Krishnan, and Emre Baydogan (Old Dominion University)

Abstract:
Developing VR applications is a challenging and rewarding endeavor, complicated by the variety and complexity of the available VR platforms. Furthermore, efficiencies realized in a specific platform may be lost if the application is migrated to a different platform. In this paper, we introduce and investigate the Common Scene Definition Framework (CSDF), a modeling representation consisting of a superset of capabilities taken from a collection of existing VR platforms. The purpose of CSDF is to serve a quick prototype framework for synthesizing an interactive virtual environment for a particular platform while attempting to optimize the translation to leverage strengths of the target platform. In an implementation independent fashion, the CSDF is envisioned to extensibly represent all geometry, appearance, interaction, and behavior for a VR application. Finally, an example is provided demonstration these basic ideas among the VRML 1.0, VRML97 and Java3D platforms.