On the Objective Evaluation of Motion Cueing in Vehicle Simulations

Motion-based simulators are used for a variety of applications, such as research, education, entertainment and training. In fact, motion cues are required to achieve the highest regulatory certifications in training vehicle simulators. Nonetheless, the reproduction of self-motion cues presents technological and economic limitations that are not present in the generation of audiovisual cues. For this reason, the generated motion does not generally match the expected one. Therefore, it is necessary to define means to assess the suitability/fidelity of the generated motion cues. After more than 50 years of motion-based vehicle simulation, no mechanism has been universally accepted as the stand…

M-GRASP: A GRASP With Memory for Latency-Aware Partitioning Methods in DVE Systems

A necessary condition for providing quality of service to distributed virtual environments (DVEs) is to provide a system response below a maximum threshold to the client computers. In this sense, latency-aware partitioning methods try to provide response times below the threshold to the maximum number of client computers as possible. These partitioning methods should find an assignment of clients to servers that optimizes system throughput, system latency, and partitioning efficiency. In this paper, we present a new algorithm based on greedy randomized adaptive search procedure with memory for finding the best solutions as possible to this problem. We take into account several different alt…

A particle swarm approach for tuning washout algorithms in vehicle simulators

Abstract The MCA tuning problem involves finding the most appropriate values for the parameters (or coefficients) of Motion Cueing Algorithms (MCA), also known as washout algorithms. These algorithms are designed to control the movements of the robotic mechanisms, referred to as motion platforms, employed to generate inertial cues in vehicle simulators. This problem can be approached in several different ways. The traditional approach is to perform a manual pilot-in-the-loop subjective tuning, using the opinion of several pilots/drivers to guide the process. A more systematic approach is to use optimization techniques to explore the vast parameter space of the MCA, using objective motion fi…

Workload Characterization in Multiplayer Online Games

In recent years, distributed virtual environments (DVEs) have become a major trend in distributed applications, mainly due to the enormous popularity of multiplayer online games in the entertainment industry. Although the workload generated by avatars in a DVE system has already been characterized, the special features of multiplayer online games make these applications to require a particular workload characterization. This paper presents the workload characterization of multiplayer online games. This characterization is based on real traces, and it shows that the movement patterns of avatars used to develop optimization techniques for DVE systems can be extrapolated to First Person Shooti…

Ensuring the performance and scalability of peer-to-peer distributed virtual environments

Large scale distributed virtual environments (DVEs) have become a major trend in distributed applications. Peer-to-peer (P2P) architectures have been proposed as an efficient and truly scalable solution for these kinds of systems. However, in order to design efficient P2P DVEs these systems must be characterized, measuring the impact of different client behavior on system performance. This paper presents the experimental characterization of P2P DVEs. The results show that the saturation of a given client has an exclusive effect on the surrounding clients in the virtual world, having no noticeable effect at all on the rest of clients. Nevertheless, the interactions among clients that can tak…

Cross-Device Augmented Reality Annotations Method for Asynchronous Collaboration in Unprepared Environments

Augmented Reality (AR) annotations are a powerful way of communication when collaborators cannot be present at the same time in a given environment. However, this situation presents several challenges, for example: how to record the AR annotations for later consumption, how to align virtual and real world in unprepared environments or how to offer the annotations to users with different AR devices. In this paper we present a cross-device AR annotation method that allows users to create and display annotations asynchronously in environments without the need for prior preparation (AR markers, point cloud capture, etc.). This is achieved through an easy user-assisted calibration process and a …

A taxonomy of augmented reality annotations

Server implementations for improving the performance of CAR systems based on mobile phones

Collaborative Augmented Reality (CAR) systems allow multiple users to share a real world environment, including computer-generated images in real time. The hardware features of most current mobile phones include wireless network capabilities that offer a natural platform for CAR systems. However, the potential number of clients in CAR systems based on mobile phones is much larger than on CAR systems based on other kind of mobile devices, requiring a system design that takes into account scalability issues. This paper presents the experimental characterization of CAR systems based on mobile phones, providing quantitative results about well-known performance metrics in distributed systems. Th…

A Comparative Evaluation of a Virtual Reality Table and a HoloLens-Based Augmented Reality System for Anatomy Training

Anatomy training with real cadavers poses many practical problems for which new training and educational solutions have been developed making use of technologies based on real-time 3-D graphics. Although virtual reality (VR) and augmented reality (AR) have been previously used in the medical field, it is not easy to select the right 3-D technology or setup for each particular problem. For this reason, this article presents a comprehensive comparative study with 82 participants between two different 3-D interactive setups: an optical-based AR setup, implemented with a Microsoft HoloLens device, and a semi-immersive setup based on a VR Table. Both setups are tested using an anatomy training s…

A New Genetic Approach for the Partitioning Problem in Distributed Virtual Environment Systems

The Partitioning problem is a key issue in the design of Distributed Virtual Environment (DVE) systems based on a server-network architecture. This problem consist of efficiently assigning the clients of the simulation (avatars) to the system servers. Despite the existing literature proposes different evolutive approaches for solving this NP-hard problem, an approach based on genetic algorithms is considered as the current best partitioning mechanism.

Comparison of WSN and IoT approaches for a real-time monitoring system of meal distribution trolleys: A case study

Abstract International regulations determine that food in hospitals and elderly homes must be served at given temperature ranges. However, the real-time surveillance of the meal distribution trolleys along all the institutions facilities, guaranteeing conformity to rules from the instant when all the meals are put in the distribution trolley until they are delivered to the patients, is still a challenge. In this paper, we present a comparison of two approaches based on Wireless Sensor Networks (WSN) and Internet of Things (IoT) technologies for implementing a Real-Time Monitoring System of Meal Distribution Trolleys in a hospital. The performance evaluation results show that the IoT impleme…

A Reconfigurable Immersive Workbench and Wall-System for Designing and Training in 3D Environments

Virtual and Augmented Reality have been widely used in many scientific fields for the last two decades in order to visualize complex data and information. Although both techniques are oriented to show users complex 3D environments by means of an intuitive and easy mechanism, they use to become useless to manipulate the information in an intuitive and realistic way. In this paper, we present SOROLLA, a new concept of workbench designed for virtual and augmented reality purposes and specially oriented to the fields of teleeducation and engineering. Unlike other proposals, SOROLLA not only allows an easy utilization and configuration, but also shows a cost-effective immersive visualization sys…

Analyzing Large-Scale Crowd Simulations for Building Evacuation

Animated virtual crowds have been used last years for analyzing human factors in scenarios where masses of people gather. A typical example is building evacuation in case of fire. Scalability still remains as an open issue for these multiagent systems applications. In this paper, we use a scalable architecture to simulate a large-scale version of a virtual crowd in a building evacuation. From the social point of view, the results provided by the large-scale version of the crowd add new and crucial information about the agents behavior, emphasizing the need for a small amount of trained leaders in order to save lives. From the system point of view, the results show that the trend of avatars …

Entertainment virtual reality system for simulation of spaceflights over the surface of the planet Mars

In recent years Virtual Reality technologies have enabled astronomers to recreate and explore three dimensional structures of the Universe for scientific purposes. Mars, due to its scientific interest,has been the focal point of numerous research projects using these technologies, however, none of these virtual reality tools have been developed specifically for entertainment purposes.The focus of this paper is to present MarsVR, as an entertainment research project that educates people on the topography and orography of the planet Mars from the perspective of popular science. Some projects have been designed MarsVR for entertainment purposes and include the latest advances in 3D real time a…

Evaluating the user experience of omnidirectional VR walking simulators

Abstract Omnidirectional treadmills (ODTs) have been traditionally proposed as a promising solution for users’ navigation in large-scale virtual environments. These mechanical devices enable users to perform locomotive motion with 360-deg freedom, while keeping their position fixed in the physical world. However, most locomotion approaches based on omnidirectional treadmills have presented either high acquisition or maintenance costs, being the capabilities of the general public, or a limited reliability. In this paper, we present a comparative usability and acceptance study with real users evaluating the two most common approaches for the development of this type of Virtual Reality (VR) wa…