Showing papers by "University of Marne-la-Vallée published in 2016"

IEEE Access Special Section Editorial: The Plethora of Research in Internet of Things (IoT)

Abstract: The plethora of research, standardization and developments in Internet of Things (IoT) has increased enormously in recent years. This is due to the vast scope of IoT. Internet of Things refers to the worldwide network of interconnected objects, which allow people or things to be connected anytime, anyplace, with anything and anyone, using any path, any network and any service. The objects have different characteristics: mobile or static, with or without energy constraint, different computation and storage capabilities, equipped with different communication technologies and sensors, etc.

Natural hazards, vulnerability and structural resilience: tsunamis and industrial tanks

Abstract: The paper presents an integrated framework which deals with natural hazards (tsunamis), physical vulnerability modelling, risk of failure for industrial structures (metal structures) and structural...

Fast Synchronization of Random Automata

Abstract: A synchronizing word for an automaton is a word that brings that automaton into one and the same state, regardless of the starting position. Cerny conjectured in 1964 that if a $n$-state deterministic automaton has a synchronizing word, then it has a synchronizing word of length at most (n-1)^2. Berlinkov recently made a breakthrough in the probabilistic analysis of synchronization: he proved that, for the uniform distribution on deterministic automata with n states, an automaton admits a synchronizing word with high probability. In this article, we are interested in the typical length of the smallest synchronizing word, when such a word exists: we prove that a random automaton admits a synchronizing word of length O(n log^{3}n) with high probability. As a consequence, this proves that most automata satisfy the Cerny conjecture.

Regularity of probability laws by using an interpolation method

Abstract: One of the outstanding applications of Malliavin calculus is the criterion of regularity of the law of a functional on the Wiener space (presented in Section 2.3). The functional involved in such a criterion has to be regular in Malliavin sense, i.e., it has to belong to the domain of the differential operators in this calculus. As long as solutions of stochastic equations are concerned, this amounts to regularity properties of the coefficients of the equation.

Autonomous Identification and Optimal Selection of Popular Smart Vehicles for Urban Sensing - An Information-centric Approach

Abstract: Today, vehicles are becoming powerful sensor platforms capable of collecting, storing, and sharing large amounts of sensory data by constant monitoring of urban streets. It is quite challenging to upload such data from all vehicles to the infrastructure due to limited bandwidth resources and high cost. This invokes the need to identify the appropriate vehicles, important for different urban sensing tasks based on their natural mobility. This paper address this problem of leveraging the self-decision making ability of a “smart vehicle” to measure its relative importance in the network. To do so, we present InfoRank as an information-centric algorithm for a vehicle to first autonomously rank different location-aware information. It then uses the information importance along its mobility pattern to find its importance in the network. We also present a selection algorithm to find the best ranked vehicles for urban sensing and vicinity monitoring to achieve a desired coverage within a limited budget. Our vehicle ranking system is the first step toward identifying the best information hubs to be used in the network for the efficient collection, storage, and distribution of urban sensory information. We evaluate InfoRank under a scalable simulation environment using realistic vehicular mobility traces. Results show that the proposed ranking system efficiently identified socially important vehicles in comparison to other ranking schemes.

Stages of melting of graphene model in two-dimensional space

Abstract: Spontaneous melting of a perfect crystalline graphene model in 2D space is studied via molecular dynamics simulation. Model containing 104 atoms interacted via long-range bond-order potential (LCBOP) is heated up from 50 to 8,450 K in order to see evolution of various thermodynamic quantities, structural characteristics and occurrence of various structural defects. We find that spontaneous melting of our graphene model in 2D space exhibits a first-order behaviour of the transition from solid 2D graphene sheet into a ring-like structure 2D liquid. Occurrence and clustering of Stone–Wales defects are the first step of melting process followed by breaking of C–C bonds, occurrence/growth of various types of vacancies and multimembered rings. Unlike that found for melting of a 2D crystal with an isotropic bonding, these defects do not occur homogeneously throughout the system, they have a tendency to aggregate into a region and liquid phase initiates/grows from this region via tearinglike or crack-propagation-like mechanism. Spontaneous melting point of our graphene model occurs at Tm = 7,750 K. The validity of classical nucleation theory and Berezinsky–Kosterlitz–Thouless–Nelson–Halperin–Young (BKTNHY) one for the spontaneous melting of our graphene model in strictly 2D space is discussed.

SPARQL query processing with Apache Spark

Abstract: The number of linked data sources and the size of the linked open data graph keep growing every day. As a consequence, semantic RDF services are more and more confronted to various "big data" problems. Query processing is one of them and needs to be efficiently addressed with executions over scalable, highly available and fault tolerant frameworks. Data management systems requiring these properties are rarely built from scratch but are rather designed on top of an existing cluster computing engine. In this work, we consider the processing of SPARQL queries with Apache Spark. We propose and compare five different query processing approaches based on different join execution models and Spark components. A detailed experimentation, on real-world and synthetic data sets, emphasizes that two approaches tailored for the RDF data model outperform the other ones on all major query shapes, i.e., star, snowflake, chain and hybrid.

French sports policies for young people: fragmentation and coordination modes

Abstract: French sports policies are characterized by hefty state controls inherited from the Gaullist era. Decentralization laws enacted from 1982 onwards defined the competences of the different institutions on the diverse levels of an administrative area, thus relieving the State of some of its functions. Therefore, sports policies for young people are numerous due to the amount of people involved at various levels of public action (national, regional, local) and because several regulating bodies are implicated (the Ministries of Sport, Education and Justice), but also due to the difficulty in articulating public and private initiatives. The aim of this paper is to bring to light, through concrete examples, the problems caused by this multi-management of sport for young people in France, but also to show the original coordination modes deriving from this situation with reference to specific projects that have sometimes required complete rethinking. This process, initiated some 30 years ago, revealed a number of ...

Post-Politics and Subaltern (De)Mobilization in an African City. Nouakchott (Mauritania)

Abstract: Whereas some scholars have shown that urban contexts are the best place for mobilization, some others have argued that the contemporary complex governance transforms the city into a “post-political” space. Focusing on urban residents’ reactions to slum clearance in Nouakchott, the capital city of Mauritania, this paper seeks to explore these two opposite theses about politics in the Southern urban contexts – the quiet encroachment paradigm versus the post-political thought. Both dynamics are useful and complementary according to the scale of analysis: depoliticization on the level of urban governance and politicization on the level of popular politics.

On the genericity of Whitehead minimality

Abstract: We show that a finitely generated subgroup of a free group, chosen uniformly at random, is strictly Whitehead minimal with overwhelming probability. Whitehead minimality is one of the key elements of the solution of the orbit problem in free groups. The proofs strongly rely on combinatorial tools, notably those of analytic combinatorics. The result we prove actually depends implicitly on the choice of a distribution on finitely generated subgroups, and we establish it for the two distributions which appear in the literature on random subgroups.

Mean-convex Alexandrov embedded constant mean curvature tori in the 3-sphere

Abstract: We introduce the moduli space of spectral curves of constant mean curvature (\cmc\hspace{-5pt}) cylinders of finite type in the round unit 3-sphere. The subset of spectral curves of mean-convex Alexandrov embedded cylinders is explicitly determined using a combination of integrable systems and geometric analysis techniques. We prove that these cylinders are surfaces of revolution. As a consequence all mean-convex Alexandrov embedded {\sc{cmc}} tori in the 3-sphere are surfaces of revolution.

How the Touring Club de France Influenced the Development of Winter Tourism

Abstract: The link between sport and tourism is closely related in outdoor sports and it is worth considering the development of these physical activities in conjunction with the tourist infrastructures that facilitate access to the activity areas. The purpose of this paper is to reveal the major role played by the Touring Club de France (TCF) in the launching of winter sports in France through its promotion of tourist infrastructures and support of the related activities. The TCF played an innovating and most efficient part through its action on three essential aspects: equipping sites for tourists; developing the manufacture of winter sports equipment; and promoting winter sports, thus bringing new life to mountain resorts. In taking into account the crucial role of the TCF in this study, the main sources used are related to the club itself: its archives and the monthly review from 1908 to 1914. On a larger scale, an explanation on how the TCF acted as a lever to generate dynamics beneficial to local deve...

Good predictions are worth a few comparisons

Abstract: Most modern processors are heavily parallelized and use predictors to guess the outcome of conditional branches, in order to avoid costly stalls in their pipelines. We propose predictor-friendly versions of two classical algorithms: exponentiation by squaring and binary search in a sorted array. These variants result in less mispredictions on average, at the cost of an increased number of operations. These theoretical results are supported by experimentations that show that our algorithms perform significantly better than the standard ones, for primitive data types.

Flag Statistics from the Ehrhart $h^∗$-Polynomial of Multi-Hypersimplices

Abstract: It is known that the normalized volume of standard hypersimplices (defined as some slices of the unit hypercube) are the Eulerian numbers. More generally, a recent conjecture of Stanley relates the Ehrhart series of hypersimplices with descents and excedences in permutations. This conjecture was proved by Nan Li, who also gave a generalization to colored permutations. In this article, we give another generalization to colored permutations, using the flag statistics introduced by Foata and Han. We obtain in particular a new proof of Stanley’s conjecture, and some combinatorial identities relating pairs of Eulerian statistics on colored permutations.

Harmonic maps with prescribed degrees on the boundary of an annulus and bifurcation of catenoids

Abstract: Let $$A \subset \mathbb {R} ^2 $$ be a smooth bounded doubly connected domain. We consider the Dirichlet energy $$E(u)=\int _{A} | abla u|^{2}$$ , where $$u:A \rightarrow \mathbb {C}$$ , and look for critical points of this energy with prescribed modulus $$|u|=1$$ on $$\partial A$$ and with prescribed degrees on the two connected components of $$\partial A$$ . This variational problem is a problem with lack of compactness. Hence we can not use the direct methods of calculus of variations. Our analysis relies on the so-called Hopf quadratic differential and on a strong link between this problem and the problem of finding all minimal surfaces bounded by two p-coverings of circles in parallel planes. We then construct new immersed minimal surfaces in $$\mathbb {R}^3$$ with this property. These surfaces are obtained by bifurcation from a family of p-coverings of catenoids.

Using Fractal Geometry to Recover the 3D Air Void, Scale-Independent, Microstructure Information From 2D Sections of Mortars

Abstract: Advances in digital image analysis have allowed for rapid and detailed investigations of the microstructural topography of cementitious materials, and recent theoretical and analytical work have allowed for recovery of 3D information from 2D analyses. However, measurements of parameters such as the entrained air void size distribution and number density obtained from digital images of concrete are sensitive to the resolution of the image. To address this, an analytical model for recovering 3D information from 2D sections was applied to images of air-entrained mortar at different resolutions, and the results were interpreted in terms of fractal geometry. It is shown that there exists a “cutoff” resolution for scale independence, which is crucial for viewing stereological measurements in an absolute sense rather than relative to the resolution of the instrument used to acquire them. For the analysis of entrained air void structure, this cutoff resolution is around 3200 DPI; for such analyses, it is recommended that images be acquired at this resolution. Furthermore, the same analytical model was validated against full 3D X-ray microtomographic images.