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匹配条件: “Michel;” ,找到相关结果约8186条。
City Development, Natural Resources and Human Impact: The Case of Medellin, Colombia  [PDF]
Michel Hermelin
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.48058

Medellin is a 3.5 M inhabitant city located in an Andean valley in northwestern Colombia. Its initial prosperity was due to agriculture and cattle-raising carried out in the valley itself and sold to the surrounding gold mining fields. The investment of these monies in coffee plantations and industry boosted the city development, accelerated urban growth, and since the middle of twentieth century, relegated food production to surrounding regions, which are also responsible for almost the totality of natural resource supply: water, electricity, food, building and industrial raw materials. Among the problems which will have to be solved in order to reach a sustainable development are relocation of population living in areas exposed to natural risks, improvement of road communications with surrounding regions and of internal public transportation and pollution control.

Main Features of a Complete Ultrasonic Measurement Model: Formal Aspects of Modeling of Both Transducers Radiation and Ultrasonic Flaws Responses  [PDF]
Michel Darmon, Sylvain Chatillon
Open Journal of Acoustics (OJA) , 2013, DOI: 10.4236/oja.2013.33A008

This paper aims at describing the theoretical fundamentals of a reciprocity-based ultrasonic measurement model. This complete inspection simulation can be decomposed in two modeling steps, one dedicated to transducer radiation and one to flaw scattering and echo synthesis. The physical meaning of the input/output signals used in these two modeling tools is defined and the theoretical principles of both field calculation and echo computation models are then detailed. The influence on the modeling results of some changes in the simulated configuration (as the incident angle) or some input signal parameters (like the frequency) are studied: it is thus theoretically established that the simulated results can be compared between each other in terms of amplitude for numerous applications when changing some inspection parameters in the simulation but that a calibration for echo calculation is generally required.

DarcyTools: A Computer Code for Hydrogeological Analysis of Nuclear Waste Repositories in Fractured Rock  [PDF]
Urban Svensson, Michel Ferry
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.26044

A computer code for simulation of groundwater flow and transport is described. Both porous and fractured media are handled by the code. The main intended application is the analysis of a deep repository for nuclear waste and for this reason flow and transport in a sparsely fractured rock is in focus. The mathematical and numerical models are described in some detail. In short, one may say that the code is based on the traditional conservation and state laws, but also embodies a number of submodels (subgrid processes, permafrost, etc). An unstructured Cartesian grid and a finite volume approach are the key elements in the discretization of the basic equations. A multigrid solver is part of the code as well as a parallelization option based on the SPMD (Single-Program Multiple-Data) method. The main application areas are summarized and an application to a deep repository is discussed in some more detail.

Urban Trends and Economic Development in China: Geography Matters!  [PDF]
Michel Dimou, Alexandra Schaffar
Current Urban Studies (CUS) , 2014, DOI: 10.4236/cus.2014.23016
Abstract: The aim of this paper is to document the role of spatial effects in the relationship between urban trends and economic development in China, between 1984 and 2004. During this period the Chi-nese urban system experienced dramatic changes, with significant rural-urban, intra-provincial and interprovincial migration, mainly after the 1993 reforms that eased the former Hukou rule and abolished the prevailing cross-region labor mobility restrictions. This study draws upon recent econometrical tools based on spatial panel data models, developed in order to deliver evidence for a linear relationship between urbanization rates and GDP per capita and an inverted-U relationship between urban primacy and GDP per capita in the Chinese provinces.
Mec1-Dependent Phosphorylation of the Scc3 Subunit of Cohesin during Mitosis in Budding Yeast  [PDF]
Nathalie Grandin, Michel Charbonneau
Advances in Bioscience and Biotechnology (ABB) , 2015, DOI: 10.4236/abb.2015.63015
Abstract: Cohesin is an evolutionary conserved complex that controls chromosome segregation during mitosis. Here we show that, in response to DNA damage, Saccharomyces cerevisiae Scc3, one of the major regulatory subunits of the Smc1-Smc3-Scc1 cohesin ring, is phosphorylated on S/T-Q residues. This event depended on the Mec1 checkpoint kinase as well as on cell cycle arrest triggered by the DNA damage checkpoint network. This phosphorylation event also took place during mitosis of an unperturbed cell cycle. The present finding that S. cerevisiae Scc3 is phosphorylated during mitosis represents a potentially important new regulatory step in cohesin’s mitotic functions.
Handling software upgradeability problems with MILP solvers
Claude Michel,Michel Rueher
Electronic Proceedings in Theoretical Computer Science , 2010, DOI: 10.4204/eptcs.29.1
Abstract: Upgradeability problems are a critical issue in modern operating systems. The problem consists in finding the "best" solution according to some criteria, to install, remove or upgrade packages in a given installation. This is a difficult problem: the complexity of the upgradeability problem is NP complete and modern OS contain a huge number of packages (often more than 20 000 packages in a Linux distribution). Moreover, several optimisation criteria have to be considered, e.g., stability, memory efficiency, network efficiency. In this paper we investigate the capabilities of MILP solvers to handle this problem. We show that MILP solvers are very efficient when the resolution is based on a linear combination of the criteria. Experiments done on real benchmarks show that the best MILP solvers outperform CP solvers and that they are significantly better than Pseudo Boolean solvers.
A Unified Community Detection, Visualization and Analysis method
Michel Crampes,Michel Plantié
Computer Science , 2013,
Abstract: Community detection in social graphs has attracted researchers' interest for a long time. With the widespread of social networks on the Internet it has recently become an important research domain. Most contributions focus upon the definition of algorithms for optimizing the so-called modularity function. In the first place interest was limited to unipartite graph inputs and partitioned community outputs. Recently bipartite graphs, directed graphs and overlapping communities have been investigated. Few contributions embrace at the same time the three types of nodes. In this paper we present a method which unifies commmunity detection for the three types of nodes and at the same time merges partitionned and overlapping communities. Moreover results are visualized in such a way that they can be analyzed and semantically interpreted. For validation we experiment this method on well known simple benchmarks. It is then applied to real data in three cases. In two examples of photos sets with tagged people we reveal social networks. A second type of application is of particularly interest. After applying our method to Human Brain Tractography Data provided by a team of neurologists, we produce clusters of white fibers in accordance with other well known clustering methods. Moreover our approach for visualizing overlapping clusters allows better understanding of the results by the neurologist team. These last results open up the possibility of applying community detection methods in other domains such as data analysis with original enhanced performances.
Overlapping Community Detection Optimization and Nash Equilibrium
Michel Crampes,Michel Plantié
Computer Science , 2014,
Abstract: Community detection using both graphs and social networks is the focus of many algorithms. Recent methods aimed at optimizing the so-called modularity function proceed by maximizing relations within communities while minimizing inter-community relations. However, given the NP-completeness of the problem, these algorithms are heuristics that do not guarantee an optimum. In this paper, we introduce a new algorithm along with a function that takes an approximate solution and modifies it in order to reach an optimum. This reassignment function is considered a 'potential function' and becomes a necessary condition to asserting that the computed optimum is indeed a Nash Equilibrium. We also use this function to simultaneously show partitioning and overlapping communities, two detection and visualization modes of great value in revealing interesting features of a social network. Our approach is successfully illustrated through several experiments on either real unipartite, multipartite or directed graphs of medium and large-sized datasets.
Visualizing and Interacting with Concept Hierarchies
Michel Crampes,Michel Plantié
Statistics , 2013,
Abstract: Concept Hierarchies and Formal Concept Analysis are theoretically well grounded and largely experimented methods. They rely on line diagrams called Galois lattices for visualizing and analysing object-attribute sets. Galois lattices are visually seducing and conceptually rich for experts. However they present important drawbacks due to their concept oriented overall structure: analysing what they show is difficult for non experts, navigation is cumbersome, interaction is poor, and scalability is a deep bottleneck for visual interpretation even for experts. In this paper we introduce semantic probes as a means to overcome many of these problems and extend usability and application possibilities of traditional FCA visualization methods. Semantic probes are visual user centred objects which extract and organize reduced Galois sub-hierarchies. They are simpler, clearer, and they provide a better navigation support through a rich set of interaction possibilities. Since probe driven sub-hierarchies are limited to users focus, scalability is under control and interpretation is facilitated. After some successful experiments, several applications are being developed with the remaining problem of finding a compromise between simplicity and conceptual expressivity.
Pool Effects on Longitudinal Dispersion in Streams and Rivers  [PDF]
Wei Zhang, Michel C. Boufadel
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.211114
Abstract: Surface storage (pools, pockets, and stagnant areas caused by woody debris, bars etc) is very important to solute transport in streams as it attenuates the peak of a spill but releases the solute back to the stream over a long time. The latter results in long exposure time of biota. Pools as fundamental stream morphology unit are commonly found in streams with mixed bed materials in pool-riffle or pool-step sequences. Fitting the transient storage model (TSM) to stream tracer test data may be problematic when pools present. A fully hydrodynamic 2-D, depth averaged advection-dispersion solute transport numerical simulation study on hypothetical stream with pool reveals that a pool can sharply enhance longitudinal spreading, cause a lag in the plume travel-time and radically increase solute residence time in the stream. These effects fade like a “wake” as the solute plume moves downstream of the pool. Further, these effects are strongly influenced by a dimensionless number derived from the 2-D transport equation ? or , which outlines the relative transverse mixing intensity of a stream or river, where, of the stream reach concerned, W is the flow width, Q0 is the volumetric flow rate, q is the longitudinal flux density, and Dt is the transverse turbulent diffusion coefficient. The breakthrough curves (BTCs) downstream of a pool may be “heavy tailed” which cannot be modeled accurately by the TSM. The internal transport and mixing condition (including the secondary circulations) in a pool together with the pool’s dimension determine the pool’s storage effects especially when >> 1. Results also suggest that the falling limb of a BTC more accurately characterizes the pool's storage because the corresponding solute has more chance to sample the entire storage area.

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