A novel dual-decomposition method for non-convex mixed integer quadratically constrained quadratic problems

In this paper, we propose the novel p-branch-and-bound method for solving two-stage stochastic programming problems whose deterministic equivalents are represented by non-convex mixed-integer quadratically constrained quadratic programming (MIQCQP) models. The precision of the solution generated by the p-branch-and-bound method can be arbitrarily adjusted by altering the value of the precision factor p. The proposed method combines two key techniques. The first one, named p-Lagrangian decomposition, generates a mixed-integer relaxation of a dual problem with a separable structure for a primal non-convex MIQCQP problem. The second one is a version of the classical dual decomposition approach that is applied to solve the Lagrangian dual problem and ensures that integrality and non-anticipativity conditions are met in the optimal solution. The p-branch-and-bound method's efficiency has been tested on randomly generated instances and demonstrated superior performance over commercial solver Gurobi. This paper also presents a comparative analysis of the p-branch-and-bound method efficiency considering two alternative solution methods for the dual problems as a subroutine. These are the proximal bundle method and Frank-Wolfe progressive hedging. The latter algorithm relies on the interpolation of linearisation steps similar to those taken in the Frank-Wolfe method as an inner loop in the classic progressive hedging.Comment: 19 pages, 5 table

The twelfth player: how FIFA challenges host states’ sovereignty. The case of the 2014 Brazil World Cup

http://www.ester.ee/record=b4684508*es

Active and frequent users of Portal de Periodicos da CAPES from Universidade Federal do Maranhão

La investigación tuvo como propósito identificar el perfil de los usuarios asiduos del Portal de Periódicos de la Capes en la Universidade Federal do Maranhão (UFMA). Se trató de un análisis descriptivo con abordaje cuantitativo basado en el estudio de caso. Participaron de la investigación 44 usuarios asiduos del Portal de Periódicos de la Capes de la UFMA. Los resultados mostraron un elevado acceso de los docentes y alumnos de postgrado stricto sensu de las áreas de Salud, Biología y de Ciencias Exactas y Tecnológicas. Las mayores dificultades identificadas en el uso del portal se referian a la identificación del texto completo, los recursos ofrecidos y el acceso remoto. Se concluye que la planificación del Portal de Periódicos de la Capes debe enfocarse en atender las demandas y necesidades de investigación de los usuarios, para así asegurar el éxito de sus servicios informacionales.The research aimed to identify the frequent user’s profile of the Journal Portal Capes at the Universidade Federal do Maranhão (UFMA). It is a descriptive field research with a quantitative approach. The research counted with 44 Portal de Periódicos da Capes of UFMA frequent users. The data collection instrument was a questionnaire with open and closed ended questions. The results indicate that the major difficulties faced in using the Portal de Periódicos da Capes refer to the identification of the full text, of the resources offered by Portal de Periódicos da Capes and remote access which reinforces the improvement of the training given. Information systems such as Portal de Periódicos da Capes aim to minimize the informational search efforts, thus conclude that the planning should be based on the profile of their clientele, that means understand the needs and demands of research permitting successful of the projects in informational services

A practical assessment of risk-averse approaches in production lot-sizing problems

This paper presents an empirical assessment of four state-of-the-art risk-averse approaches to deal with the capacitated lot-sizing problem under stochastic demand. We analyse two mean-risk models based on the semideviation and on the conditional value-at-risk risk measures, and alternate first and second-order stochastic dominance approaches. The extensive computational experiments based on different instances characteristics and on a case-study suggest that CVaR exhibits a good trade-off between risk and performance, followed by the semideviation and first-order stochastic dominance approach. For all approaches, enforcing risk-aversion helps to reduce the cost-standard deviation substantially, which is usually accomplished via increasing production rates. Overall, we can say that very risk-averse decision-makers would be willing to pay an increased price to have a much less risky solution given by CVaR. In less risk-averse settings, though, semideviation and first-order stochastic dominance can be appealingalternatives to provide significantly more stable production planning costs with a marginal increase of the expected costs.Peer reviewe

A decomposition strategy for decision problems with endogenous uncertainty using mixed-integer programming

Despite methodological advances for modeling decision problems under uncertainty, faithfully representing endogenous uncertainty still proves challenging, both in terms of modeling capabilities and computational requirements. A novel framework called Decision Programming provides an approach for solving such decision problems using off-the-shelf mathematical optimization solvers. This is made possible by using influence diagrams to represent a given decision problem, which is then formulated as a mixed-integer linear programming problem. In this paper, we focus on the type of endogenous uncertainty that received less attention in the introduction of Decision Programming: conditionally observed information. Multi-stage stochastic programming (MSSP) models use conditional non-anticipativity constraints (C-NACs) to represent such uncertainties, and we show how such constraints can be incorporated into Decision Programming models. This allows us to consider the two main types of endogenous uncertainty simultaneously, namely decision-dependent information structure and decision-dependent probability distribution. Additionally, we present a decomposition approach that provides significant computational savings and also enables considering continuous decision variables in certain parts of the problem, whereas the original formulation was restricted to discrete variables only. The extended framework is illustrated with two example problems. The first considers an illustrative multiperiod game and the second is a large-scale cost-benefit problem regarding climate change mitigation. Neither of these example problems could be solved with existing frameworks.Comment: 26 pages, 10 figure

ANÁLISE DOS VALORES DOS PRODUTORES RURAIS FRENTE À COOPERATIVA AO QUAL ESTÃO ASSOCIADOS

A gestão empresarial tem avançado em sua forma de atuação, deixando de lado uma postura convencional de busca de lucro e rentabilidade para um enfoque preferencialmente voltado à sustentabilidade de seus negócios e de seus acionistas. Uma cooperativa não tem a perspectiva de distribuir riquezas para os acionistas, uma vez que trabalha com foco no desenvolvimento social do ambiente em que se insere e de seus membros, embora cada vez mais convive com a necessidade de um adequado faturamento para sua sobrevivência e de seus cooperados. Para que isso se efetive, se faz necessário conhecer quais são os valores de seus associados para que estratégias possam emergir e serem implementadas com vistas a uma maior satisfação dos associados e conseqüentemente maiores retornos em seus negócios. Utilizando-se destes elementos, o presente trabalho buscou identificar quais os valores considerados pelos cooperados, bem como a fidelidade destes para com a cooperativa ao qual são associados. Tal estudo desenvolveu na cidade de Unaí/MG. Dentro dos resultados encontrados neste estudo, ressalta-se que a maioria dos entrevistados é fiel à sua parceira, mas 18,8% disseram que se houvesse outro local que lhe pagasse melhor pela sua produção ele deixaria de entregá-la para a cooperativa; dentre os atributos valorizados pelos associados, foi destaque: a maior confiança e segurança dada pela cooperativa; local para entregar o seu produto quando necessário; e oportunidade de melhor compra de insumos. Disseram também que quem mais lhes prejudica em seu negócio rural é o governo, e quem mais lhe ajuda é a própria cooperativa. Quanto aos procedimentos metodológicos para a realização deste estudo, utilizou-se uma abordagem quantitativa, por meio de um Survey junto a 400 produtores rurais de três cooperativas do Município. ---------------------------------------------The enterprise management has advanced in its form of performance, leaving of side a conventional position of search of profit and yield for an approach preferential directed to the sustentabilidy of its businesses and its stakeholders. The cooperative does not have the perspective to distribute wealth for the stakeholders, a time that works with focus in the social development of the environment where if it inserts and of its members, even so each time more coexists the necessity of one adjusted invoicing for its survival and of cooperated its. So that this if accomplishes, if it makes necessary to know which are the values of its associates so that strategies can emerge and be implemented, with sights to a bigger satisfaction of the associates and consequently bigger returns in its businesses. Using itself of these elements, the present work searched to identify to which the values considered for the cooperated ones, as well as the allegiance of these stops with the cooperative to which is associates. Such study it developed in the city of Unaí/MG. Inside of the results found in this study, it is standed out that the majority of the interviewed ones is faithful to its partner, but 18.8% had said that another place was had that it better paid to it for its production would leave to deliver it for the cooperative; amongst the attributes valued for the associates, it was prominence: the biggest confidence and security given for the cooperative; place to deliver its when necessary product; e chance of better purchase of inputs resources. They had also said that who more harms to them in its agricultural business is the government, and who more it aid is the proper cooperative. How much to the methodological procedures for the accomplishment of this study, a quantitative boarding was used, by means of a together Survey the 400 agricultural producers of three cooperatives of the City.valores dos produtores rurais, cooperativas, estratégias de marketing, values of the producer agricultural, cooperative, marketing strategies, Farm Management,

Twist Removal Of Healed Vs. Nonhealed Implants-a Mechanical And Histological Study In Mini Pigs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The objective of this study was to evaluate the effect of removal torque (reverse torque) of titanium implants in peri-implant bone. Methods: The P1-M1 teeth were extracted bilaterally of 6 mini pigs (BR-1). Each animal received 6 titanium implants, three for each side of mandible. On the right side of mandible, 3 implants reminded 9 months (9M) under masticatory activity and on the left side, other 3 implants were placed and immediately removed (IR). All 36 implants were removed by removal torque, and the recorded values were statistically analyzed. Animals were euthanized right after the removal torque and recording. Each third (cervical, medium, and apical) of peri-implant bone was extracted and analyzed histological and immunohistochemically. Student's t test was used to determine statistical differences in the values between the 9M and IR samples. Data were presented as means with standard deviations. The level of significance was set at 5% (P < 0.05). Results: Removal torque was higher in 9M experimental situation than in IR. Histological characteristics of mature bone were presented in the 9M experimental condition, and immature bone characteristics were presented in the IR experimental condition. Removal torque caused small fractures and rounding in the bone grooving. Immunohistochemical analysis reinforced the histological results; Student's t test provided statistically significant differences to osteocalcin expression in 9M samples and no statistically significant differences expression to collagen I in both experimental conditions (P < 0.05). Conclusions: Removal torque caused microscopical fractures and smoothing in the peri-implant bone grooves, but it does not compromise the bone healing.2CAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Utility-Scale Energy Storage in an Imperfectly Competitive Power Sector

Interest in sustainability has increased the share of variable renewable energy sources (VRES) in power generation. Energy storage systems' potential to mitigate intermittencies from non-dispatchable VRES has enhanced their appeal. However, the impacts of storage vary based on the owner and market conditions. We examine the policy implications of investments in utility-scale battery storage via a bi-level optimization model. The lower level depicts power system operations, modeled as either perfect competition or Cournot oligopoly to allow for the assessment of producer market power. The upper-level investor is either a welfare-maximizer or a profit-maximizing standalone merchant to reflect either welfare enhancement or arbitrage, respectively. We implement a realistic case study for Western Europe based on all possible size-location storage investment combinations. We find that market competition affects investment sizes, locations, and their profitability more than the investor's objectives. A welfare-maximizer under perfect competition invests the most in storage capacity. Consumers typically gain most from storage investments in all cases, exceeding the gains for the investors. Specifically, our results show that storage investments may either not occur or be located differently than at social optimum, if market power is exerted. Thus, policy makers need to anticipate producer market power when setting regulation

O concepturo: do direito romano ao Código civil

- Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.- Localização na estante: 347.65'158 O48