No abstract

Virtual Reality (VR) has been constantly evolving since its early days, and is now a fundamental technology in different application areas. User evaluation is a crucial step in the design and development of VR systems that do respond to users' needs, as well as for identifying applications that indeed gain from the use of such technology. Yet, there is not much work reported concerning usability evaluation and validation of VR systems, when compared with the traditional desktop setup. The paper presents a user study performed, as a first step, for the evaluation of a low-cost VR system using a Head-Mounted Display (HMD). That system was compared to a traditional desktop setup through an experiment that assessed user performance, when carrying out navigation tasks in a game scenario for a short period. The results show that, although users were generally satisfied with the VR system, and found the HMD interaction intuitive and natural, most performed better with the desktop setup.

Location-routing is a branch of locational analysis that takes into account distribution aspects. This paper proposes a taxonomy, with two levels, for location-routing problems. The first level focuses on the structural characteristics of the problems. The second level branches into the different algorithmic approaches and objective perspectives. An introduction to the previously defined problems is presented, categorising the papers in the literature (a total of 149 references) according to the proposed classification. Moreover, an overview of the most significant aspects of the different solution methods and main objectives, with special emphasis on multi-objective approaches, is provided. Some data providing a better insight into the publication progress are also included. Finally, several promising research directions are identified.