Towards Effective Exact Algorithms for the Maximum Balanced Biclique Problem

The Maximum Balanced Biclique Problem (MBBP) is a prominent model with numerous applications. Yet, the problem is NP-hard and thus computationally challenging. We propose novel ideas for designing effective exact algorithms for MBBP. Firstly, we introduce an Upper Bound Propagation procedure to pre-compute an upper bound involving each vertex. Then we extend an existing branch-and-bound algorithm by integrating the pre-computed upper bounds. We also present a set of new valid inequalities induced from the upper bounds to tighten an existing mathematical formulation for MBBP. Lastly, we investigate another exact algorithm scheme which enumerates a subset of balanced bicliques based on our upper bounds. Experiments show that compared to existing approaches, the proposed algorithms and formulations are more efficient in solving a set of random graphs and large real-life instances

Electronic design: a new field of investigation for large scale optimization

International audienceMobile phones, music players, personal computers, set-top boxes and countless other digital electronics items are part of our daily life. These nomad devices offer more and more functionnality. For example, recent mobile phones allow to communicate, to take pictures, to play video, to listen to the music, to watch TV, to access to the Internet... Thus, the integrated circuit (IC) achieving all these functions become more and more complex. Designers aim at developping these products taking into account two main axes: - shorten the delay to reach the market - reduce the size of these devices For a long time, designers are using a lot of optimization techniques such as Integer Linear Programming, heuristics and metaheuristics. A two year observation of those behaviors has led to the following conclusions, even if the electronic community know these techniques, there is a great need for more formal techniques, more appropriate models and efficient soving approaches especially designed for their specific problems. The talk, after a global introduction will introduce several problems where the help from the metaheuristic is needed and for which collaborations are necessary. This talk will be the starting point of the creation of a network for long term collaborations

Métaheuristiques pour l'allocation de mémoire dans les systèmes embarqués

National audienceLa gestion de la mémoire cache a un impact significatif sur les performances et sur la consommation énergétique des systèmes embarqués. Cet article traite de l'allocation de mémoire des structures de données d'une application à la mémoire cache de manière à optimiser les performances du système. Les concepteurs de circuits souhaitent trouver un compromis entre le coût de l'architecture (le nombre de bancs mémoire à embarquer) et la consommation électrique. Le problème abordé consiste à allouer un banc mémoire à toute structure de données de manière à minimiser les conflits d'accès aux données. Le modèle proposé pour ce problème est le k-weighted graph coloring problem. Une formulation par PLNE et deux métaheuristiques basées respectivement sur une recherche taboue et sur un algorithme hybride à base de population sont comparées sur un ensemble d'instances. Les résultats obtenus sont encourageants et suggèrent que l'utilisation de méthodes issues de la coloration de graphes est une piste prometteuse pour l'allocation de mémoire dans les systèmes embarqués

Grado de relación entre el clima laboral y el desempeño de los colaboradores de la empresa Adidas sede Trujillo Mall Plaza, en el trimestre del año 2018

"El objetivo de esta investigación fue determinar el grado de relación entre las variables clima laboral y desempeño de los colaboradores de la empresa ADIDAS sede Trujillo Mall Plaza. La hipótesis de trabajo que se formuló fue: El grado de relación entre el clima laboral y el desempeño de los colaboradores de la empresa ADIDAS sede Trujillo Mall Plaza, en el II Trimestre del año 2018, es positiva considerable; es decir, se esperaba hallar que el coeficiente de relación rho de Spearman se ubicaría en el rango comprendido entre los valores +0.51 y +0.75. La población del estudio estuvo constituida por 24 trabajadores, considerando que el número de sujetos de la población fue pequeño, el tamaño de la muestra fue de 23 trabajadores, excluyendo al gerente. El diseño de investigación elegido fue el descriptivo correlacional. Los datos fueron recolectados utilizando la técnica encuesta, mediante la herramienta cuestionario; la técnica entrevista mediante el instrumento guía de preguntas; y la técnica observación, a través del instrumento lista de cotejo. Mediante un análisis estadístico no-paramétrico, la investigación concluyó que sí existe una relación directa y significativa entre el clima laboral y el desempeño de los colaboradores de la empresa ADIDAS sede Trujillo Mall Plaza. El valor hallado para la rho de Spearman fue de +0.524, con un nivel de significancia de 0.01 (p-valor) < 0.05, lo que implica una relación positiva considerable y permite aceptar la hipótesis de trabajo propuesta. ""The objective of this research was to determine the grade of relation between the variables work climate and employees´ performance of ADIDAS company, Trujillo Mall Plaza. The working hypothesis that was formulated: The grade of relation between the work climate and the employees´ performance of ADIDAS company Trujillo Mall Plaza, in the II trimester of 2018, is considerable positive; that is, we expected to find that Spearman's rho ratio coefficient would be in the range between the values +0.51 and +0.75. The studied population consisted of 24 workers, considering that the number of subjects in the population was small, the sample size was 23 workers, excluding the manager. The research design chosen was the descriptive correlational. Data were collected using: the survey technique using the questionnaire instrument, the interview technique using the question guide instrument and the observation technique through the checklist instrument. Through a non-parametric statistical analysis, the research concluded that there is a direct and significant relation between the work climate and the employees´ performance of the ADIDAS company, Trujillo Mall Plaza. The value found for the Spearman rho was +0.524, with a level of significance of 0.01 (p-value) < 0.05, which implies a considerable positive relation and allows accepting the proposed work hypothesis. "Tesi

Os Contratos de Licenciamento e a Eficiência Técnica dos Setores Industriais Brasileiros: Uma Análise à Luz do Método de Fronteira Estocástica e da Análise Envoltória de Dados (DEA)

The paper addresses the relationship between licenses and technical efficiency in a set of Brazilian industrial sectors. The main hypothesis is that licenses are negatively related with technical efficiency. To test this hypothesis, a stochastic and a non-parametric frontier were estimated for ten industrial sectors in the period from 1992 to 2000. Three results were found out: First, licenses and efficiency are negatively related; Second, the law’s adjustment contributed to the efficiency to all sectors. Third, law’s adjustment also emphasized the negative effect of licenses on technical efficiency. The arguments are the following: The first result is associated with licenses acting as entries barriers to specific industries. In the second argument, the law could have provided incentives to other aspects of industrial property other than the licenses, such as innovations, for an example. The third result may be associated with the inclusion of the compulsory license mechanism in the law, which may result in an increase in the number of licenses and also reducing the competition inside each sector, due to its compulsory aspects evolving firm behavior.Fronteira Estocástica, DEA, Contratos de Licenciamento, Reforma da Lei de Propriedade Industrial, Eficiência Técnica

Optimization issues in phenotyping plateforms

International audienceThe combined effects of climate change and population growth have made agriculture appear as one of the most important challenge of the century. In order to be able to produce food for everyone in the coming decades, there is an urgent need to build more knowledge about plants, and how to grow them in a sustainable way, i.e., how to produce enough biomass without resorting to pollutant chemicals inputs. Hence, plant biologists need to understand what makes plants resistant to diseases, parasites, insects and hydric stress, among other environment effects. The functional plant body, called the phenotype, is the result of the combination of the plan genotype with the environment: two plants with the same DNA will not have the same development under different environment conditions. As the so-called \textit{plant performance} is the result of phenotype, a lot of effort has recently been devoted to study plants phenotype. More specifically, biologists run large scale experiments on hundreds or thousands of plants, for example to determine how resistant is a particular plant to a wide range of environment conditions. To this end, the plants are settled in pots, and these pots are moved by a conveyor belt from a cultivation chamber to different quantitative automated measurement stations, where RGB cameras, spectrography and other techniques are employed to monitor plants growth on a regular basis. The European project EPPN2020 aims at gathering a large number of such facilities to share experience and accelerate the research progresses in plant biology. It currently involves 31 plant phenotyping platforms and 21 partners across Europe from 12 countries (including the Slovak University of Agriculture in Nitra), under the coordination of INRA, with a budget of \euro 10 million for four years. It can be observed that the phenotyping platforms available in EPPN2020 and everywhere else in the world have a very similar structure

Custos fiscais da política monetária: os efeitos indiretos de um choque de juros sobre a dívida líquida do setor público

The paper estimates the fiscal cost of an increase in the Brazilian policy interest rate - the SELIC - by considering not only the direct effect on the yield of public bonds that are indexed to the SELIC, but also indirect effects on: (i) the yield of public bonds that are indexed to the exchange rate and inflation, and (ii) the stock of public net debt through adjustments in the value of international reserves measured in domestic currency. Projections are based on the estimation of the relationship between interest rates, exchange rates and inflation by means of a vector auto-regression. We conclude that the inclusion of such indirect effects has an ambiguous effect on the response of the implicit interest rate on public net debt to shocks in the SELIC, when adjustments in the value of international reserves are not considered. However, the inclusion of the latter amplifies the fiscal cost of a more restrictive monetary policy. These results call for a better coordination between monetary, fiscal and exchange rate policies in Brazil.The paper estimates the fiscal cost of an increase in the Brazilian policy interest rate - the SELIC - by considering not only the direct effect on the yield of public bonds that are indexed to the SELIC, but also indirect effects on: (i) the yield of pub363557579sem informaçãosem informaçãoO artigo estima o custo fiscal de um aumento da taxa básica de juros da economia considerando não apenas os efeitos diretos sobre a remuneração dos títulos indexados à SELIC, mas também os efeitos indiretos que incidem sobre: (i) a remuneração dos título