A delay and cost balancing protocol for message routing in mobile delay tolerant networks

The increasing pervasiveness of mobile devices with networking capabilities has led to the emergence of Mobile Delay Tolerant Networks (MDTNs). The characteristics of MDTNs, which include frequent and long-term partitions, make message routing a major challenge in these networks. Most of the existing routing protocols either allocate an unlimited number of message copies or use a xed number of message copies to route a message towards its destination. While the first approach unnecessarily oods the network, the rigidity of the second approach makes it ine cient from the viewpoint of message replication. Hence, the question that we address in this paper is: "How to dynamically allocate message copies in order to strike a balance between the delay and cost of message delivery?". We present a novel adaptive multi-step routing protocol for MDTNs. In each routing step, our protocol reasons on the remaining time-tolive of the message in order to allocate the minimum number of copies necessary to achieve a given delivery probability. Experiment results demonstrate that our protocol has a higher delivery ratio and a lower delivery cost compared to the state-of-the-art Spray-and-Wait and Bubble protocols

ACCIO: How to Make Location Privacy Experimentation Open and Easy

The advent of mobile applications collecting and exploiting the location of users opens a number of privacy threats. To mitigate these privacy issues, several protection mechanisms have been proposed this last decade to protect users' location privacy. However, these protection mechanisms are usually implemented and evaluated in monolithic way, with heterogeneous tools and languages. Moreover, they are evaluated using different methodologies, metrics and datasets. This lack of standard makes the task of evaluating and comparing protection mechanisms particularly hard. In this paper, we present ACCIO, a unified framework to ease the design and evaluation of protection mechanisms. Thanks to its Domain Specific Language, ACCIO allows researchers and practitioners to define and deploy experiments in an intuitive way, as well as to easily collect and analyse the results. ACCIO already comes with several state-of-the-art protection mechanisms and a toolbox to manipulate mobility data. Finally, ACCIO is open and easily extensible with new evaluation metrics and protection mechanisms. This openness, combined with a description of experiments through a user-friendly DSL, makes ACCIO an appealing tool to reproduce and disseminate research results easier. In this paper, we present ACCIO's motivation and architecture, and demonstrate its capabilities through several use cases involving multiples metrics, state-of-the-art protection mechanisms, and two real-life mobility datasets collected in Beijing and in the San Francisco area

Deux règles d'ivoire trouvées à pompéi (Campanie)

National audienceDuring the last years, we have conducted a comprehensive study on pigment-pots and painters' equipments from Pompeii. The study of house I.9.9 gave us a precise idea of how a workshop of painters functioned, its style, its location, and the division of roles within it. This essay focuses on particularly interesting artifacts found in two different contexts. The irst interesting artifact was recovered from a house under restoration on the Eve of the eruption (Reg. I, ins. 16, houses 2, 3, 4). A team of painters was about to paint the lararia and some of the rooms of these dwellings. The second one was found in the House of Verus (I.VI. 3) where was the groma. In these two houses were rulers made of ivory inely engraved with a pattern of great interest. This paper describes the rulers, compares them and concludes that painters of Pompeii had a high lEvel technique knowledge because the pattern can be considered as a pattern of perspective, supposed to be codiied in the Renaissance

A Comparison of the Crystal Structures of Phospholipase A2 from Bovine Pancreas and Crotalus atrox Venom

The refined high resolution crystal structure of the bovine phospholipase A2 was compared with its counterpart from the venom of Crotalus atrox, the western diamondbacked rattlesnake. The strong similarity in their backbone conformations forms the basis of a common numbering system for the amino acid sequence. The three common major helices and much of the extended chain form a nearly identical “homologous core” structure. The variations in conformation usually arise from deletions/insertions or en bloc shifts of structural units. The exception to this is part of the highly conserved calcium-binding loop; however, this is to be expected as 1) there is no calcium ion sequestered in the venom dimer as there is in the case of the bovine enzyme and 2) two side chains in that segment form dimer-stabilizing interactions between the subunits of the C. atrox enzyme. The absolutely conserved catalytic network of hydrogen-bonded side chains formed by His 48, Tyr 52, Tyr 73, and Asp 99, as well as the hydrophobic wall that shields it, are virtually superimposable in the two structures. However, the details of the structural relationship between the amino terminus and the catalytic network differ in the two species and the ordered water molecules thought to be either functionally or structurally important in the pancreatic enzymes are not found in the crystal structure of the phospholipase A2 from C. atrox. The most striking difference from a functional stand-point is the fact that the surface depression in the region of the catalytic network that has been commonly considered the active site is shielded substantially in forming the intersubunit contact surface of the dimeric venom enzyme