Search results for " algorithm"

Optimization of Data Harvesters Deployment in an Urban Areas for an Emergency Scenario

2013

International audience; Since its appearance in the VANETs research community, data collection where vehicles have to explore an area and collect various local data, brings various issues and challenges. Some architectures were proposed to meet data collection requirements. They can be classified into two categories: Decentralized and Centralized self-organizing where different components and techniques are used depending on the application type. In this paper, we treat time-constrained applications in the context of search and rescue missions. For this reason, we propose a centralized architecture where a central unit plans and manages a set of vehicles namely harvesters to get a clear ove…

Optimization of net power density in Reverse Electrodialysis

2019

Abstract Reverse Electrodialysis (RED) extracts electrical energy from the salinity difference between two solutions using selective ion exchange membranes. In RED, conditions yielding a large net power density (NPD) are generally desired, due to the still large cost of the membranes. NPD depends on a large number of physical and geometric parameters. Some of these, for example the inlet concentrations of concentrate and diluate, can be regarded as “scenario” variables, imposed by external constraints (e.g., availability) or chosen by different criteria than NPD maximization. Others, namely the thicknesses HCONC, HDIL and the velocities UCONC, UDIL in the concentrate and diluate channels, c…

Evolutionary algorithm for fiber laser in ultrashort pulse regime

2016

This thesis deals with the generation of ultrashort pulses within a fiber laser cavity through the automatic optimization of its parameters by an evolutionary algorithm. The interest of this subject comes from the difficulty to systematically explore dynamics in a large domain of experimental parameters. We have shown that it is possible to implement an evolutionary algorithm on fiber laser cavity with appropriate precautions. We have experimentally demonstrated for the first time the mode locking of a laser cavity only using the optimization of polarization controllers through an automatic and self-learning procedure. We also have demonstrated that selecting the mode locking from it radio-…

Contribution à l'étude de la formation des images optiques en microscopie champ proche optique: effet de la sonde en deux dimensions

2004

This work consists in the development of a theoretical tool for the purpose to undertake numerical simulations able to take into account the coupling between the probe and the object. The first part, concerns the combination of the differential method and the algorithms T and S, to overcome numerical problems which appear in the cases where the size of system (probe - object) is more realistic. The developed global model is two-dimensional and applied in polarization TE under the normal diffraction condition. We have used the developed model to study the formation of optical image by monomodes and multimodes probes. The obtained optical images at constant height, have allowed us to study th…

Vehicles, replicators, and intercellular movement of genetic information: evolutionary dissection of a bacterial cell.

2012

Prokaryotic biosphere is vastly diverse in many respects. Any given bacterial cell may harbor in different combinations viruses, plasmids, transposons, and other genetic elements along with their chromosome(s). These agents interact in complex environments in various ways causing multitude of phenotypic effects on their hosting cells. In this discussion I perform a dissection for a bacterial cell in order to simplify the diversity into components that may help approach the ocean of details in evolving microbial worlds. The cell itself is separated from all the genetic replicators that use the cell vehicle for preservation and propagation. I introduce a classification that groups different r…

2019

Abstract This paper examines the labor-market returns to a new form of postsecondary vocational education: vocational master's degrees. We use individual fixed effects models on a matched sample of students and non-students from Finland to capture any time-invariant differences across individuals. We find that attendance in vocational master's programs leads to an earnings increase of more than seven percent five years after entry. The estimated effect remains positive even if selection on unobservables is twice as strong as selection on observables. Earnings gains are similar by gender and age, but they are marginally higher for those in the health sector than for those in the business or …

The labour market consequences of self-employment spells:European evidence

2008

Hundreds of thousands of Europeans enter self-employment each year, but because self-employment spells are typically brief, many of them exit soon after entry. We examine how those who return to paid-employment fare on the labour market using the European Community Household Panel (ECHP). Like earlier evidence for the US, ours indicate that, in general, brief spells of self-employment do not increase average hourly earnings upon return to paid-employment. For highly educated men, an additional year of self-employment actually decreases their earnings by 4-5% relative to a year of continued wage employment. We also find that brief spells of self-employment are associated with increased proba…

Hedging foreign exchange rate risk: Multi-currency diversification

2016

Abstract This article proposes a multi-currency cross-hedging strategy that minimizes the exchange risk. The use of derivatives in small and medium-sized enterprises (SMEs) is not common but, despite its complexity, can be interesting for those with international activities. In particular, the reduction in the exchange risk borne through the use of natural multi-currency cross-hedging is measured, considering Conditional Value-at-Risk (CVaR) and Value-at-Risk (VaR) for measuring market risk instead of the variance. CVaR is minimized using linear programmes, while a multiobjective genetic algorithm is designed for minimizing VaR, considering two scenarios for each currency. The results obtai…

Average-case analysis in an elementary course on algorithms

1998

Average-case algorithm analysis is usually viewed as a tough subject by students in the first courses in Computer Science. Traditionally, these topics are fully developed in advanced courses with a clear mathematical orientation. The work presented here is not an alternative to this, but, it presents the analysis of algorithms (and average-case in particular) adapted to the mathematical background of students in an elementary course on Algorithms or Programming by using some specially selected examples.

Using Cellular Automata for feature construction - preliminary study

2007

When first faced with a learning task, it is often not clear what a good representation of the training data should look like. We are often forced to create some set of features that appear plausible, without any strong confidence that they will yield superior learning. Beside, we often do not have any prior knowledge of what learning method is the best to apply, and thus often try multiple methods in an attempt to find the one that performs best. This paper describes a new method and its preliminary study for constructing features based on cellular automata (CA). Our approach uses self-organisation ability of cellular automata by constructing features being most efficient for making predic…