Efficient Algorithms for Large-Scale Topology Discovery

in ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems (2005, June)

There is a growing interest in discovery of internet topology at the interface level. A new generation of highly distributed measurement systems is currently being deployed. Unfortunately, the research ... [more ▼]

There is a growing interest in discovery of internet topology at the interface level. A new generation of highly distributed measurement systems is currently being deployed. Unfortunately, the research community has not examined the problem of how to perform such measurements efficiently and in a network-friendly manner. In this paper we make two contributions toward that end. First, we show that standard topology discovery methods (e.g., skitter) are quite inefficient, repeatedly probing the same interfaces. This is a concern, because when scaled up, such methods will generate so much traffic that they will begin to resemble DDoS attacks. We measure two kinds of redundancy in probing (intra- and inter-monitor) and show that both kinds are important. We show that straightforward approaches to addressing these two kinds of redundancy must take opposite tacks, and are thus fundamentally in conflict. Our second contribution is to propose and evaluate Doubletree, an algorithm that reduces both types of redundancy simultaneously on routers and end systems. The key ideas are to exploit the tree-like structure of routes to and from a single point in order to guide when to stop probing, and to probe each path by starting near its midpoint. Our results show that Doubletree can reduce both types of measurement load on the network dramatically, while permitting discovery of nearly the same set of nodes and links. [less ▲]

Efficient and robust simulation of tissue differentiation in fracture healing

in Proceedings of the European Conference on Mathematical and Theoretical Biology (2005)

An efficient automata approach to some problems on context-free grammars

in Information Processing Letters (2000), 74(5-6), 221-227

Book and Otto (1993) solve a number of word problems for monadic string-rewriting systems using an elegant automata-based technique. In this note we observe that the technique is also very interesting ... [more ▼]

Book and Otto (1993) solve a number of word problems for monadic string-rewriting systems using an elegant automata-based technique. In this note we observe that the technique is also very interesting from a pedagogical point of view, since it provides a uniform solution to several elementary problems on context-free languages. [less ▲]

Efficient biochemical monitoring and survival assessment after an acute myocardial infarction

in Clinical Chemistry (1984), 5(abstr suppl.1), 187

An efficient biphasic synthesis of polymer-grafted reduced graphite oxide based nanocomposites

Poster (2011, March 03)

Efficient database pruning for large-scale cover song recognition

in International Conference on Acoustics, Speech, and Signal Processing (ICASSP) (2013, May)

This paper focuses on cover song recognition over a large dataset, potentially containing millions of songs. At this time, the problem of cover song recognition is still challenging and only few methods ... [more ▼]

This paper focuses on cover song recognition over a large dataset, potentially containing millions of songs. At this time, the problem of cover song recognition is still challenging and only few methods have been proposed on large scale databases. We present an efficient method for quickly extracting a small subset from a large database in which a correspondence to an audio query should be found. We make use of fast rejectors based on independent audio features. Our method mixes independent rejectors together to build composite ones. We evaluate our system with the Million Song Dataset and we present composite rejectors offering a good trade-off between the percentage of pruning and the percentage of loss. [less ▲]

An efficient DNA isolation protocol for filamentous cyanobacteria of the genus Arthrospira

in Journal of Microbiological Methods (2010), 80

Thanks to their photosynthetic and nutritive properties, cyanobacteria of the Arthrospira genus are of interest as food supplements, as efficient oxygen producing life support system organisms for manned ... [more ▼]

Thanks to their photosynthetic and nutritive properties, cyanobacteria of the Arthrospira genus are of interest as food supplements, as efficient oxygen producing life support system organisms for manned space flight, and for the production of biofuels. Despite these potential valuable applications, full genome sequences and genetic information in general on Arthrospira remain scarce. This is mainly due to the difficulty to extract sufficient high molecular weight nucleic acids from these filamentous cyanobacteria. In this article, an efficient and reproducible DNA extraction procedure for cyanobacteria of the genus Arthrospira was developed. The method is based on the combination of a soft mechanical lysis with enzymatic disruption of the cell wall. The comparison with other extraction protocols clearly indicates that this optimised method allows the recovery of a larger amount of DNA. Furthermore, the extracted DNA presents a high molecular weight, a reduced degradation and an excellent overall quality. It can be directly used for molecular biology purposes such as PCR, and clone library construction. [less ▲]

An efficient dynamic state estimator for large-scale electric power systems

in Proceedings of the IFAC Symposium on Power Systems. Modelling and Control applications (1988)

An Efficient Flamelet-based Combustion Model for Supersonic Flows

in 17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011, Vol. 2; No AIAA 2011-2267 (2011, April)

A combustion model based on a Flamelet/Progress Variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and ... [more ▼]

A combustion model based on a Flamelet/Progress Variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and tabulated species mass fractions. The combustion is thus modeled by 3 additional scalar equations and a chemistry table that is computed in a pre-processing step. This approach is very efficient and allows the use of complex chemical mechanisms. An approximation is also introduced to eliminate costly iteration steps during the temperature calculation. To better account for compressibility e ects, the source term for the progress variable is rescaled with the pressure. The model is tested in both RANS and LES computations of a hydrogen jet in a supersonic transverse flow. Comparison with experimental measurements shows good agreement, particularly in the LES case. It is also found that the disagreement between RANS results and experimental data is mostly due to the mixing model de ciencies used in RANS. [less ▲]

Efficient hydraulic numerical modeling with multiblock grids and linked models

in Houille Blanche (2011), 3

In the field of numerical hydraulic engineering, the size of the simulations is one of the current challenges to consider with sufficient precision the large areas involved by practical applications. In ... [more ▼]

In the field of numerical hydraulic engineering, the size of the simulations is one of the current challenges to consider with sufficient precision the large areas involved by practical applications. In this scope, the linking in the same computational domain of different solvers, each one used in the part of the simulation where its characteristics are most suitable, opens the door to huge modeling possibilities. Such optimized hydraulic numerical modeling is presented in this paper with a multiblock multimodel 2D solver and its linking to a 1D model. After a description of the solvers, with emphasis on the linking procedures, theoretical test cases and real applications are presented. [less ▲]