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This chapter proposes a context modeling process to help tutors adapt their tutorship actions based on students’ profiles and performance on Technology Enhanced Learning environments (TEL). It attempts also to involve teachers as designers in the engineering process of a TEL system development and to support their activity of auto-regulation regarding the students’ guidance and assistance. This aim leads to improve teaching strategies as well as to enhance the quality of the learning objects and the learning scenario itself. In fact, if the TEL system is already adaptive, by means of this approach, its improvement is fostered. If not, the process will support its iterative transformation from predefined to adaptive. The Model Driven Engineering (MDE) methodology is used since it gives educational designers (teachers for this proposal) and software designers the ability to define, communicate, and test a solution while creating artifacts that become part of the overall solution. The Usage Tracking Language (UTL) has been developed to provide the actors of a TEL system (designers, tutors, learners, and analysts) with a dutiful tool to describe the observed uses of the descriptive pedagogical scenario and their semantics, including the definition of the observation needs and the means required for data acquisition. The structure of tracks and their transformations from raw data allows the calculation of indicators which supports the building of users’ models that will influence users’ decision making. Finally, a case study using the Hop3X environment for learning Java programming to apply this process is presented.

2013, IX, 349 p. 79 illus., 55 in color; International audience; We discuss models that astrochemists have developed to study the chemical composition of the interstellar medium. These models aim at computing the evolution of the chemical composition of a mixture of gas and dust under astrophysical conditions. These conditions, as well as the geometry and the physical dynamics, have to be adapted to the objects being studied because different classes of objects have very different characteristics (temperatures, densities, UV radiation fields, geometry, history etc); e.g., proto-planetary disks do not have the same characteristics as proto-stellar envelopes. Chemical models are being improved continually thanks to comparisons with observations but also thanks to laboratory and theoretical work in which the individual processes are studied.

International audience; We describe an approach to extract 13C-labeled sugars (glucose, fructose, maltose, sucrose, myo-inositol as well as glucose from starch) from plant tissues and to analyze their isotopomer distribution by gas chromatography–mass spectrometry (GC-MS). Sugars are derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) into their Si(CH3)3 derivatives. Electronic and chemical ionizations are used to obtain suitable fragments for metabolic flux analysis (MFA). Unique fragments are identified by computer simulation and experimental verification with labeled standards. Linear equations for separating information from glucosyl and fructosyl moieties of sucrose are presented. Finally, mass distributions are corrected for natural isotope abundance using a home-written program. The method is illustrated by sugar isotopomer analysis of 13C-labeled rapeseed embryos.

Abstract The serotonergic system plays a key modulatory role in the brain. This system is critical in many drug developments for brain disorders via interactions with the 14 subtypes of 5-HT receptors or through reuptake blockade. Positron emission tomography (PET) is an efficient tool for in vivo studies of physiological and pathological processes. Because of its pertinent radiochemical properties, fluorine-18 is one of the most used radioisotopes in PET imaging. This chapter will propose an overview of the 18F-radioligands targeting serotonin receptors, which have been developed over the last few years. Both radiosyntheses and pharmacological properties of these radiotracers will be described, with a specific emphasis on their potential medical applications.

This chapter examines the interactive communications of geographically distant virtual classrooms, connected via virtual aids ranging from e-mails to videoconferences. The combination is crucial: through diverse filters, virtual teams mediate a final text for a new language and culture. The authors use linguistic pragmatics as a mechanism to analyze and assess the efficiency and the meaningfulness of such communications. They then use this approach to recommend best practices for educators teaching in cross-cultural virtual environments.

International audience; The relative efficiency of auctions and negotiations is still a puzzle in the literature. While auctions are the prescribed procedures and the most used ones for public procurement, in the private sector, where buyers are free to choose their purchasing method, competitive tendering is far from being their preferred option (Bajari et al. 2009). In addition, recent empirical studies (Estache et al. 2009, Bajari et al. 2009) highlight some failures of auction procedures and identify conditions under which negotiation is more efficient. In particular, they show that auctions perform poorly when projects are complex. In this paper, our aim is to contribute to this debate by providing an empirical analysis of how awarding mechanisms are chosen in public procurement in France. To this end, we examine a comprehensive database of 76,188 observations corresponding to the entire set of public procurement work contracts awarded between 2005 and 2007 in the construction sector. We find empirical regularities regarding the choice of awarding procedures by public buyers. However, most of these regularities do not coincide with what the theoretical literature considers as transaction-cost minimizing behaviours. In particular, the size of the construction projects as well as the length of contracts do not appear as key determinants of the choice of awarding procedures, which translates into costly renegotiations.

Part 6: Network Modeling; International audience; Mobile Adhoc Networks (MANET) are susceptible to jamming attacks which can inhibit data transmissions. There has been considerable work done in the detection of external jamming attacks. However, detection of insider jamming attack in MANET has not received enough attention. The presence of an insider node that has constantly monitored the network and is privy to the network secrets can acquire sufficient information to cause irreparable damage. In this paper we propose a framework for a novel reputation-based coalition game between multiple players in a MANET to prevent internal attacks caused by an erstwhile legitimate node. A grand coalition is formed which will make a strategic security defense decision by depending on the stored transmission rate and reputation for each individual node in the coalition. Our results show that the simulation of the reputation-based coalition game would help improve the network’s defense strategy while also reducing false positives that results from the incorrect classification of unfortunate legitimate nodes as insider jammers.

In many real-life applications (e.g., in aircraft maintenance), we need to estimate the probability of failure of a complex system (such as an aircraft as a whole or one of its subsystems). Complex systems are usually built with redundancy allowing them to withstand the failure of a small number of components. In this paper, we assume that we know the structure of the system, and, as a result, for each possible set of failed components, we can tell whether this set will lead to a system failure. For each component A, we know the probability P(A) of its failure with some uncertainty: e.g., we know the lower and upper bounds P(A) and P(A) for this probability. Usually, it is assumed that failures of different components are independent events. Our objective is to use all this information to estimate the probability of failure of the entire the complex system. In this paper, we describe several methods for solving this problem, including a new efficient method for such estimation based on Cauchy deviates.