Rafael J. Martínez-Durá

Serious Games for Health and Safety Training

EUROSTAT figures show that 5720 people die in the European Union every year as a consequence of work-related accidents. Training in Health and Safety is indeed a key aspect to reduce this figure, and serious games constitute an effective method to provide this training. However, the development of this type of computer applications is a complex issue, requiring cross discipline knowledge on different areas, including instructional design, psychology, sociology, law, and computer graphics. Beyond the challenges already present in the development of non-educational computer games, serious games for health and safety are instructional tools. Therefore, they require an instructional design to cover specific educational issues, and knowledge on the health and safety regulations which are applicable in each particular context. In addition, these games have as their ultimate goal to increase the worker’s awareness about safety regulations and reduce the number and seriousness of accidents. Thus, the evaluation of this type of applications must be rather different from the evaluation of other games with a focus on entertainment. In this chapter we provide a description of existing serious games in the health and safety area, and describe major instructional and technological aspects related to the development of this type of training tools. Although technological developments will indeed increase the advantages of serious games as a means to deliver instruction in health and safety, we believe that the most challenging issues remain at the instructional side, and further research is still needed to maximize the effectiveness of this kind of training.

Physically-Based Interactive Sand Simulation

The interactive simulation of 3D terrains has been approached from sever al perspectives. Due to the complexity of the system involved, most of the models proposed focus on a visually realis tic animation of the scene, rather than on a physically-based accurate simulation of a granular system. Those m lack generality when interacting with the environment; in most cases, no reaction forces are computed, co nsidering only soil deformation. This limitation reduces their usability in applications such as driving simulators. We pr opose the use of a theoretical discrete model that considers normal forces for 3D real-time simulation of granular systems. We also extend this model to consider horizontal forces, allowing a wider range of interaction s. Several numerical tests have been implemented and detailed results have been analyzed which show a good mo del performance.

Elevation cable modeling for interactive simulation of cranes

In this paper, the way to simulate hoisting cables in real time is addressed. We overcome instability in such simulation by considering a two-layered model: a model for the dynamics of a cable passing through a set of pulleys and an oscillation model based on the classical one-dimensional wave equation. The first layer considers the interaction between the cable and pulleys with the elevation equipment, while the second layer simulates cable oscillation. Numerical instability is avoided by suspending the oscillation layer when required. Due to the system properties, this can be carried out in such a way that does not cause significant loss in the system quality. It considers the oscillation of the cable between every pair of pulleys, collision detection and the variation of the cable length very efficiently. Rendering issues are discussed, with remarks on how to prevent aliasing artifacts in the cable. Efficiency is analyzed, including performance tests which show that the model can be run very efficiently. The paper also covers how to integrate the model in a complex multibody simulation with a high degree of interactivity.

Crane collision modelling using a neural network approach

Abstract The objective of the present work is to find a Collision Detection algorithm to be used in the Virtual Reality crane simulator (UVSim®), developed by the Robotics Institute of the University of Valencia for the Port of Valencia. The method is applicable to box-shaped objects and is based on the relationship between the colliding object positions and their impact points. The tool chosen to solve the problem is a neural network, the multilayer perceptron, which adapts to the characteristics of the problem, namely, non-linearity, a large amount of data, and no a priori knowledge. The results achieved by the neural network are very satisfactory for the case of box-shaped objects. Furthermore, the computational burden is independent from the object positions and how the surfaces are modelled; hence, it is suitable for the real-time requirements of the application and outperforms the computational burden of other classical methods. The model proposed is currently being used and validated in the UVSim Gantry Crane simulator.

A Mixed Model for Real‐Time, Interactive Simulation of a Cable Passing Through Several Pulleys

A model of a cable and pulleys is presented that can be used in Real Time Computer Graphics applications. The model is formulated by the coupling of a damped spring and a variable coefficient wave equation, and can be integrated in more complex mechanical models of lift systems, such as cranes, elevators, etc. with a high degree of interactivity.

Texture advection on discontinuous flows

Texture advection techniques, which transport textures using a velocity field, are used to visualize the dynamics of a flow on a triangle mesh. Some flow phenomena lead to velocity fields with discontinuities that cause the deformation of the texture which is not properly controlled by these techniques. We propose a method to detect and visualize discontinuities on a flow, keeping consistent texture advection at both sides of the discontinuity. The method handles the possibility that the discontinuity travels across the domain of the flow with arbitrary velocity, estimating its speed with least-squares approximation. The technique is tested with different sample scenarios and with two avalanche scenes, showing that it can run at interactive rates.

Simulador de realidad virtual para la formación de operadores de grúa Torre

La utilizacion de simuladores basados en realidad virtual proporciona una solucion a los diferentes inconvenientes del entrenamiento de operadores de maquinaria pesada. Entre las ventajas aportadas al ambito de formacion, se encuentran la reduccion de riesgos laborales y costes economicos, el incremento en la productividad, y la utilizacion como herramienta objetiva de evaluacion. Este articulo presenta un sistema instruccional basado en simulacion para el entrenamiento de operadores de grua Torre. Este simulador destaca por su enfoque formativo mediante la inclusion de material docente interactivo, el aprendizaje en la maniobrabilidad de una grua Torre a traves de un conjunto de ejercicios y circuitos de entrenamiento, y la utilizacion de tecnicas de realidad virtual del estado del arte (como shaders de iluminacion, tecnicas de sombreado y avatares cooperativos) que incrementan la experiencia de realismo obtenida. Se describe la arquitectura que compone el simulador, el diseno del entorno virtual basado en OpenSceneGraph, el sistema de autoevaluacion, y las caracteristicas de realismo del modelo dinamico de la grua, como son la influencia del viento y las colisiones de los cables con otros objetos del entorno virtual. El sistema se complementa con un puesto de instructor que facilita el control, la evaluacion, y la monitorizacion de los puestos de entrenamiento de un aula multipuesto.

Analysis of a Cable Model, Considering Mass and Wave Oscillations

Theoretical cable‐pulley dynamics models usually lead to computationally expensive numerical models. For this reason, both mass and cable oscillation are usually neglected when efficiency is an issue. Recently a new model has been presented that allows the simulation of cable oscillation and catenary with low computational cost. In this paper, we present a preliminary analysis of the dynamics of the model, based on numerical tests. More precisely, we analyze the influence of the main parameters of the model over its dynamics, taking as a reference the massless models used so far.