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61.
Yehuda Afek Eli Gafni Sergio Rajsbaum Michel Raynal Corentin Travers 《Distributed Computing》2010,22(3):185-195
This paper introduces and investigates the k-simultaneous consensus task: each process participates at the same time in k independent consensus instances until it decides in any one of them. It is shown that the k-simultaneous consensus task is equivalent to the k-set agreement task in the wait-free read/write shared memory model, and furthermore k-simultaneous consensus possesses properties that k-set does not. In particular we show that the multivalued version and the binary version of the k-simultaneous consensus task are wait-free equivalent. These equivalences are independent of the number of processes. Interestingly, this provides us with a new characterization of the k-set agreement task that is based on the fundamental binary consensus problem. 相似文献
62.
Véronique Souchère Laurent Millair Javier Echeverria François Bousquet Christophe Le Page Michel Etienne 《Environmental Modelling & Software》2010,25(11):1359-1370
Erosive runoff is a recurring problem and is a source of sometimes deadly muddy floods in the Pays de Caux (France). The risk results from a conjunction of natural factors and human activity. Efficient actions against runoff in agricultural watersheds are well known. However they are still difficult to implement as they require co-operation between stakeholders. Local actors thus need tools to help them understand the collective consequences of their individual decisions and help to initiate a process of negotiation between them. We decided to use a participatory approach called companion modelling (ComMod), and, in close collaboration with one of the first group of local stakeholders, to create a role-playing game (RPG) to facilitate negotiations on the future management of erosive runoff. This paper describes and discusses the development of the RPG and its use with other groups of local stakeholders within the framework of two game sessions organized by two different watershed management committees. During the joint construction step, stakeholders shared their viewpoints about the environment, agents, rules, and how to model runoff in preparation for the creation of the RPG. During the RPG sessions, two groups of eight players, including farmers, mayors and watershed advisors, were confronted with disastrous runoff in a fictive agricultural watershed. Results showed that they managed to reduce runoff by 20–50% by engaging a dialogue about grass strips, storage ponds and management of the intercrop period. However, further progress is still needed to better control runoff through the implementation of better agricultural practices because, during the RPG sessions, the watershed advisors did not encourage farmers to do so. Because of the complexity of management problems, results of jointly constructing the game and the RPG sessions showed that modelling and simulation can be a very useful way of accompanying the collective learning process. This new way of working was welcomed by the participants who expressed their interest in organizing further RPG sessions. 相似文献
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65.
Souleiman Naciri Naoufel Cheikhrouhou Michel Pouly Jean-Charles Binggeli Rémy Glardon 《Expert systems with applications》2011,38(2):1203-1212
Nowadays, all product life cycle processes are investigated deeply in order to get an advantage over competitors. To support these processes, several software applications are available. However, this wide range of heterogeneous applications leads to a large variety of hardware and operating systems, data management software, data models, schemas, and data semantics that hinder the information sharing process. To tackle this problem, Hitachi Company has developed a modeling language called Generic Product Model (GPM) in addition to several translators from native formats to GPM for storing, sharing and visualizing product data in a single data warehouse. In order to broaden the range of application data able to be stored and shared using the GPM data warehouse, this paper presents a methodology and a translator that allow management data to be included in a GPM data warehouse. Given the fact that most management data are stored in Enterprise Resource Planning (ERP) software, and that the latter allows extraction of database contents into Excel files, we propose a translator that handles Enterprise Resource Planning management data that are already extracted into Excel Format.The proposed framework enables data management contained in flat Excel Files to be translated into structured GPM data. Translation methodologies are given for the translation of mass production and customized product data through two case studies, one in the computer retail sector and the other in the extrusion machine industry. 相似文献
66.
This paper describes an efficient Web page detection approach based on restricting the similarity computations between two
versions of a given Web page to the nodes with the same HTML tag type. Before performing the similarity computations, the
HTML Web page is transformed into an XML-like structure in which a node corresponds to an open-closed HTML tag. Analytical
expressions and supporting experimental results are used to quantify the improvements that are made when comparing the proposed
approach to the traditional one, which computes the similarities across all nodes of both pages. It is shown that the improvements
are highly dependent on the diversity of tags in the page. That is, the more diverse the page is (i.e., contains mixed content
of text, images, links, etc.), the greater the improvements are, while the more uniform it is, the lesser they are. 相似文献
67.
Thomas Neumann Matthias Bender Sebastian Michel Ralf Schenkel Peter Triantafillou Gerhard Weikum 《Distributed and Parallel Databases》2009,26(1):3-27
Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a
central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper
introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the
frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping
input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and
3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network
nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms,
efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments,
with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style
network. 相似文献
68.
Interlayer cooling potential in vertically integrated packages 总被引:2,自引:1,他引:1
T. Brunschwiler B. Michel H. Rothuizen U. Kloter B. Wunderle H. Oppermann H. Reichl 《Microsystem Technologies》2009,15(1):57-74
The heat-removal capability of area-interconnect-compatible interlayer cooling in vertically integrated, high-performance chip stacks was characterized with de-ionized water as coolant. Correlation-based predictions and computational fluid dynamic modeling of cross-flow heat-removal structures show that the coolant temperature increase due to sensible heat absorption limits the cooling performance at hydraulic diameters ≤200 μm. An experimental investigation with uniform and double-side heat flux at Reynolds numbers ≤1,000 and heat transfer areas of 1 cm2 was carried out to identify the most efficient interlayer heat-removal structure. The following structures were tested: parallel plate, microchannel, pin fin, and their combinations with pins using in-line and staggered configurations with round and drop-like shapes at pitches ranging from 50 to 200 μm and fluid structure heights of 100–200 μm. A hydrodynamic flow regime transition responsible for a local junction temperature minimum was observed for pin fin in-line structures. The experimental data was extrapolated to predict maximal heat flux in chip stacks having a 4-cm2 heat transfer area. The performance of interlayer cooling strongly depends on this parameter, and drops from >200 W/cm2 at 1 cm2 and >50 μm interconnect pitch to <100 W/cm2 at 4 cm2. From experimental data, friction factor and Nusselt number correlations were derived for pin fin in-line and staggered structures. 相似文献
69.
Optimal assembly plan generation: a simplifying approach 总被引:3,自引:0,他引:3
The main difficulty in the overall process of optimal assembly plan generation is the great number of different ways to assemble
a product (typically thousands of solutions). This problem confines the application of most existing automated planning methods
to products composed of only a limited number of components. The presented method of assembly plan generation belongs to the
approach called “disassembly” and is founded on a new representation of the assembly process, with introduction of a new concept,
the equivalence of binary trees. This representation allows to generate the minimal list of all non-redundant (really different) assembly plans. Plan generation is directed by assembly operation constraints and plan-level performance
criteria. The method was tested for various assembly applications and compared to other generation approaches. Results show
a great reduction in the combinatorial explosion of the number of plans. Therefore, this simplifying approach of assembly
sequence modeling allows to handle more complex products with a large number of parts. 相似文献
70.