Collision detection: review of methods and recent advances in crowd simulation

Crowd simulation is a large complex system that visualizes the behavior of crowd entities' movement and their interactions with the virtual environment. Crowd model is usually integrated into a virtual environment to make the environment alive. In the context of agent-based simulation (as in crowd simulation), it encompasses collision checking between moving agents that are present in the same environment. Hence, it is important to design an efficient and yet effective collision detection in crowd simulation. This is to ensure that it is cost effective toward computational processing usage and still produce a believable behavior. This paper presents a study of collision detection techniques in crowd models, and recent advancement to accelerate the process so that in turn, these efforts could also improve the performance and outcome of crowd model in virtual environment applications

Virtual Operator Models for Off-highway Machine Virtual Prototyping

Increasing demands on the world’s resources require the design of off-highway machines that provide greater functionality and productivity along with greater efficiency. Model-based or virtual design provides a means for achieving these design improvements with reduced time and costs. However, virtual design is often limited by the fidelity with which human operators are modeled. A greater understanding of how highly skilled operators obtain high machine performance and productivity can inform machine development and advance agricultural and construction machine automation technology. This research investigated how machine operator expertise, strategies, and decision-making can be integrated into operator models that simulate authentic human behavior in construction machine operations. The initial effort of this work was to develop a virtual operator model (VOM) through a combination of human factors and physical system modeling techniques. Operator interviews were conducted to build a framework of tasks, strategies, and cues commonly used while controlling an excavator through repeated work cycles. A closed loop simulation demonstrated that a VOM could simulate the trenching work cycle and enable closed-loop virtual equipment operation simulation. Advancing the state of the art in operator modeling requires models that can adapt. Approaches to enable a generic virtual operator model to adapt to changes in the environment based on the operator’s actions were investigated. The closed loop simulation performed successfully when using the VOM, the vehicle model, and an environment model which represented how the VOM adapted during a complete trenching operation

KNOWLEDGE MANAGEMENT FOR BUSINESS ORIENTED FOREIGN LANGUAGE TEACHING AND LEARNING

A research team from two universities and two IT companies took the challenge of developing a business foreign languages program implemented in a web environment, aiming the effectiveness of the communication in a working multicultural environment, using foreign languages. The online educational portal for applied foreign languages teaching and learning addressing the cross-cultural dimension represents the core of the Romanian academic research project (eMulticult), financed under the national Romanian research scheme (National Council for Project Management - Partnership Program). The present contribution summarizes the concepts and the methodology of the project, aiming at increasing professionals’ adaptability to a specific corporate cultural environment in order to create conditions for openness, tolerance, harmony and cooperation in the working and social environment. The studies will end up in creating a knowledge portal for the development of adequate cultural attitudes and skills specific to a foreign language professional environment. The project develops a holistic approach for the design of a conceptual framework based on a web educational model for foreign language acquisition and the internalization of its cultural values and the implementation of the model in a virtual environment using an adequate pedagogical approach and complex training tools. The foreign language educational model makes reference to the Anderson’s and Krathwohl’s taxonomy, articulating it with the dimensions of the specific corporate culture. The web based paradigm and tools of the educational model will facilitate for the beneficiaries the online learning process. The originality of this approach consists in the synergy among various views and models such as person oriented education, multicultural approach, use of the virtual environment for providing educational services. The portal integrates educational packages for individual beneficiaries, virtual classes, formal or informal educational networks, and the tools for e-content developing. The educational platform offers the premise for building the empathic attitude, through a deep understanding of the own cultural matrix and a greater permeability to the behavior and values of another cultural & organizational environment, increasing the degree of communication and integration at European level.Foreign language teaching, cross-cultural approach, educational model, training engineering

A new class of neural architectures to model episodic memory : computational studies of distal reward learning

A computational cognitive neuroscience model is proposed, which models episodic memory based on the mammalian brain. A computational neural architecture instantiates the proposed model and is tested on a particular task of distal reward learning. Categorical Neural Semantic Theory informs the architecture design. To experiment upon the computational brain model, embodiment and an environment in which the embodiment exists are simulated. This simulated environment realizes the Morris Water Maze task, a well established biological experimental test of distal reward learning. The embodied neural architecture is treated as a virtual rat and the environment it acts in as a virtual water tank. Performance levels of the neural architectures are evaluated through analysis of embodied behavior in the distal reward learning task. Comparison is made to biological rat experimental data, as well as comparison to other published models. In addition, differences in performance are compared between the normal and categorically informed versions of the architecture

Affordances In The Design Of Virtual Environments

Human-computer interaction design principles largely focus on static representations and have yet to fully incorporate theories of perception appropriate for the dynamic multimodal interactions inherent to virtual environment (VE) interaction. Theories of direct perception, in particular affordance theory, may prove particularly relevant to enhancing VE interaction design. The present research constructs a conceptual model of how affordances are realized in the natural world and how lack of sensory stimuli may lead to realization failures in virtual environments. Implications of the model were empirically investigated by examining three affordances: passability, catchability, and flyability. The experimental design involved four factors for each of the three affordances and was implemented as a 2 [subscript IV] [superscript 4-1] fractional factorial design. The results demonstrated that providing affording cues led to behavior closely in-line with real-world behavior. More specifically, when given affording cues participants tended to rotate their virtual bodies when entering narrow passageways, accurately judge balls as catchable, and fly when conditions warranted it. The results support the conceptual model and demonstrate 1) that substituting designed cues via sensory stimuli in available sensory modalities for absent or impoverished modalities may enable the perception of affordances in VEs; 2) that sensory stimuli substitutions provide potential approaches for enabling the perception of affordances in a VE which in the real world are cross-modal; and 3) that affordances relating to specific action capabilities may be enabled by designed sensory stimuli. This research lays an empirical foundation for a science of VE design based on choosing and implementing design properties so as to evoke targeted user behavio

Chip-controlled 3-D complex cutting tool insert design and virtual manufacturing simulation

Designing suitable tools for the turning operation is of vital interest to manufacturers. The tool inserts used nowadays adopt complex geometric shapes. A question facing many manufacturers is how to effectively design complex shaped tool inserts and how to prove the validity of such design. One of the important criteria for selecting inserts is the ability to control chip formation and chip breaking;The research work described in this dissertation attempted to bring innovation into the cutting tool insert design process by using feature-based modeling and by proposing a predictive chip model and integrating it into the design process. Such model integration makes the tool insert design a much more effective process and also enhances the decision-making required in insert design;A new 3-D kinematic chip model was developed to depict chip behavior in a complex groove insert. The model derived showed the analytical relationships between chip shape parameters and chip motion parameters. This dissertation explained how the kinematic model could be modified to take into account all possible 3-D complex groove shapes. A mathematical model was also developed from experimental data to serve the current need for cutting tool design;Other research work presented in this dissertation is the simulation of the machining process in a virtual environment. The virtual machining simulation can be of great benefit for researchers in manufacturing to use the platform as a testbed for product development and testing

Modeling Color Appearance in Augmented Reality

Augmented reality (AR) is a developing technology that is expected to become the next interface between humans and computers. One of the most common designs of AR devices is the optical see-through head- mounted display (HMD). In this design, the virtual content presented on the displays embedded inside the device gets optically superimposed on the real world which results in the virtual content being transparent. Color appearance in see-through designs of AR is a complicated subject, because it depends on many factors including the ambient light, the color appearance of the virtual content and color appearance of the real background. Similar to display technology, it is vital to control the color appearance of content for many applications of AR. In this research, color appearance in the see-through design of augmented reality environment is studied and modeled. Using a bench-top optical mixing apparatus as an AR simulator, objective measurements of mixed colors in AR were performed to study the light behavior in AR environment. Psychophysical color matching experiments were performed to understand color perception in AR. These experiments were performed first for simple 2D stimuli with single color both as background and foreground and later for more visually complex stimuli to better represent real content that is presented in AR. Color perception in AR environment was compared to color perception on a display which showed they are different from each other. The applicability of the CAM16 color appearance model, one of the most comprehensive current color appearance models, in AR environment was evaluated. The results showed that the CAM16 is not accurate in predicting the color appearance in AR environment. In order to model color appearance in AR environment, four approaches were developed using modifications in tristimulus and color appearance spaces, and the best performance was found to be for Approach 2 which was based on predicting the tristimulus values of the mixed content from the background and foreground color

Three essays on behavioral economics and mechanism design

My three essays on behavioral economics and mechanism design introduce two new microeconomic theoretical models. In the first chapter, we develop an n-player theoretical model applying the concept of Virtual Bargaining to study cooperative behavior in public goods games characterizing team production. Virtual Bargaining is a modeling framework that characterizes how players may construct a tacit agreement to coordinate behavior in the absence of explicit communication. Players identify their worst-possible payoff outcome from any candidate agreement, and mutually best-respond with respect to maximization of their worst-payoff function. Players face uncertainties regarding whether other players will follow through on a candidate agreement or play their Nash best response to candidate agreement. The worst payoff function is the minimum over these possibilities. We show that, relative to the Nash equilibrium predictions, the virtual bargaining model predicts more effective coordination with higher contributions to the public good when individual contributions are strategically complementary and the public good production technology exhibits decreasing return to scale. This type of public good characterizes team production processes when each player receives a share of the total team output, and effort by each player increases the marginal product of every other player. In the second chapter, based on the different theoretical predictions of the VB and standard Nash models, we propose an experimental design to test whether the VB or the standard Nash model predicts people’s behavior better. What\u27s more, we also test the VB theory in a price-setting duopoly market environment. In the third chapter, we show that hidden information regarding the quality of placements of online advertisements by publishers can lead to inefficiency in the market that is a form of moral hazard. We then characterize an incentive-compatible contract between the publisher and a traditional contract advertiser in the online display advertisements environment. This solves the inefficient impression allocation problem between the traditional contract market and the real-time bidding spot market. Unlike previous papers, which rely on including the reputation or long-term benefit consideration into the publisher’s objective function, our incentive-compatible contract characterizes a one-time profit maximization problem for the publisher

Virtual prototyping of pressure driven microfluidic systems with SystemC-AMS extensions

The design of "Lab on a Chip" microfluidic devices is, typically, preceded by a long and costly period of prototyping stages in which the system is gradually refined by an iterative process, involving the manufacturing of a physical prototype and the making of a lot of laboratory experiments. In this scenario, a virtual prototyping framework which allows the emulation of the behavior of the complete system is greatly welcome. This paper presents such a framework and details a virtual prototyping methodology able to soundly handle microfluidic behavior based on SystemC-AMS extensions. The use of these extensions will permit the communication of the developed microfluidic models with external digital or mixed signal devices. This allows the emulation of the whole Lab on a Chip system as it usually includes a digital control and a mixed-signal reading environment. Moreover, as SystemC-AMS is also being extended to cover other physical domains within the CATRENE CA701 project, interactions with these domains will be possible, for example, with electromechanical or optical parts, should they be part of the system. The presented extensions that can manage the modeling of a micro-fluidic system are detailed. Two approaches have been selected: to model the fluid analytically based on the Poiseuille flow theory and to model the fluid numerically following the SPH (Smoothed Particle Hydrodynamics) approach. Both modeling techniques are, by now, encapsulated under the TDF (Timed Data Flow) MoC (Model of Computation) of SystemC-AMS.This work has been supported by CATRENE CA701H-INCEPTION Projec