Noname manuscript No. (will be inserted by the editor) Multi-scale query processing in vehicular networks T. Delot · S. Ilarri · M. Thilliez · G. Vargas-Solar · S. Lecomte Received: date / Accepted: date Abstract In the last decade, a number of wireless and small-sized devices (e.g., PDAs, smartphones, sensors, laptops, etc.) with increasing computing capabilities have appeared in the market at very affordable costs. These devices have started to be embedded in mod- ern cars in the form of on-board computers, GPS nav- igators, or even multimedia centers. Thus, the vehicles can carry useful information, acting as data sources for other vehicles. Recently, some works have addressed the problem of processing queries in such highly dy- namic vehicular networks in order to share information between drivers. The proposed query processing tech- niques usually rely on a push model. Hence, each vehicle receives data from its neighbors and decides whether they are relevant enough to be stored in a local data cache. Then, the data may be used by a query proces- sor to retrieve relevant data for the driver. In this paper, we look at the problem from a broader perspective and discuss the interest of multi-scale query processing techniques in such context. The goal of such techniques is to exploit, at the mobile device’s level, dif- T. Delot, M. Thilliez and S. Lecomte University Lille North of France LAMIH FRE UHVC/CNRS 3304 Valenciennes, France Tel.: +33 3 27 51 19 56 Fax: +33 3 27 51 19 40 E-mail: Firstname.Lastname@univ-valenciennes.fr S. Ilarri University of Zaragoza IIS Department Zaragoza, Spain E-mail: silarri@unizar.es G. Vargas-Solar CNRS, LIG-LAFMIA Grenoble, France E-mail: Genoveva.Vargas-Solar@imag.fr ferent access modes (e.g., push, pull) and various data sources (e.g., data cached locally, data stored by vehi- cles nearby, remote Web services, etc.) to provide the users with results for their queries. We highlight the most important challenges and outline some possible approaches. We also present a prototype of a first query evaluator developed using the Microsoft LINQ API. Keywords Mobile Data Management · Vehicular Networks · Multi-Scale Query Processing · Network applications & services 1 Introduction Mobile devices and wireless networks are now wide- spread, and continuous technological advances are ob- served in this area. Today, many people use small de- vices to retrieve different types of data every day. The importance of mobile data will grow even more in the upcoming years. Thus, ABI Research estimates that “In 2014, the volume of mobile data sent and received every month by users around the world will exceed by a significant amount the total data traffic for all of 2008” 1 . All these trends are motivating a great amount of research to try to develop suitable data management strategies for mobile computing. Research in data management for mobile computing started already in the 90’s, with several papers study- ing the problems introduced by the –at that time– new environment [6,20,21,37]. Specifically, the emergence of both handheld devices and wireless networks has had a strong impact on query processing techniques [22, 1 See http://www.abiresearch.com/press/1466-In+2014+ Monthly+Mobile+Data+Traffic+Will+Exceed+2008+Total, Accessed May 9, 2011.