A linear programming based heuristic framework for min-max regret combinatorial optimization problems with interval costs

This work deals with a class of problems under interval data uncertainty, namely interval robust-hard problems, composed of interval data min-max regret generalizations of classical NP-hard combinatorial problems modeled as 0-1 integer linear programming problems. These problems are more challenging than other interval data min-max regret problems, as solely computing the cost of any feasible solution requires solving an instance of an NP-hard problem. The state-of-the-art exact algorithms in the literature are based on the generation of a possibly exponential number of cuts. As each cut separation involves the resolution of an NP-hard classical optimization problem, the size of the instances that can be solved efficiently is relatively small. To smooth this issue, we present a modeling technique for interval robust-hard problems in the context of a heuristic framework. The heuristic obtains feasible solutions by exploring dual information of a linearly relaxed model associated with the classical optimization problem counterpart. Computational experiments for interval data min-max regret versions of the restricted shortest path problem and the set covering problem show that our heuristic is able to find optimal or near-optimal solutions and also improves the primal bounds obtained by a state-of-the-art exact algorithm and a 2-approximation procedure for interval data min-max regret problems

Robust Determinants Of Reservation Wages In Colombia

First prong of this work analyzes effects of an early-shock, the 1999 Colombia Earthquake on the development of cognitive skills. Second prong analyzes the effects of professional skills on reservation wages

Summability characterizations of positive sequences

In this paper, we propose extensions for the classical Kummer test, which is a very far-reaching criterion that provides sufficient and necessary conditions for convergence and divergence of series of positive terms. Furthermore, we present and discuss some interesting consequences and examples such as extensions of the Olivier's theorem and Raabe, Bertrand and Gauss's test.Comment: 12 pages (Accepted for publication in Communications in Mathematics in June 17, 2020

A long way from tax justice: the Brazilian case

This paper presents the major characteristics of the Brazilian tax system, after underlining the modifications it went through since 1988, when the country adopted a new and democratic Constitution. One important feature is the marked incidence of indirect consumer and production taxes (49% of all tax revenues) in place of direct taxes on income, inheritance, and capital gains. This imbalance between indirect and direct taxes explains, in large part, the elevated regressivity of the Brazilian tax system, which both expresses and reproduces the profound inequalities that characterize Brazilian society

Implementação de Sticky Policies em um provedor OpenID Connect

TCC(graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Sistemas de Informação.Com o crescente mercado de sistemas web, deve crescer também o cuidado das organizações com os dados sensíveis dos usuários de seus serviços, em especial dados de identificação, também chamados de PII (personally identifiable information), enviados pelos usuários para as suas aplicações. Quando usuários compartilham seus dados com um serviço, devem ter controle sobre o uso destes e certeza que o destino destes dados será cumprido, além das regras quanto ao seu uso ou divulgação a terceiros. As políticas de privacidade são os documentos que destinam-se a ajudar o usuário a entender sobre o tratamento dos dados após a coleta. Através delas, o usuário é questionado ou informado sobre as informações coletadas, o uso dessas informações, o tempo de retenção ou da divulgação das mesmas. O OpenID Connect, que conta com diversas implementações Open Source e baseado no protocolo OAuth 2.0, visa garantir autenticação e autorização entre um usuário e o serviço desejado. Para tanto, fornece as informações sobre o usuário final na forma de um token, que contém as informações básicas de perfil sobre o usuário. Através deste trabalho, foi realizada a implementação de uma extensão em um provedor de identidades que utiliza o protocolo OpenID Connect, permitindo o envio de políticas de privacidade no contexto da utilização do serviço, juntamente com as informações básicas contidas no token. Para tal, é utilizado o contexto de Sticky Policies, que agrega as políticas de privacidade aos dados do usuário normalmente enviados pelo protocolo OpenID Connect, permitindo que o usuário de um serviço tenha controle sobre a aplicação e divulgação de seus dados.As the web systems market grows up, organizations concern with services classified users data must grow as well, especially identification data, also called PII - Personally Identifiable Information, which is sent from the users to companies applications. When users share their data with a service, they must have control upon it’s destination and make sure it’s purpose will be fulfilled, beyond third party usage and disclosure rules. Privacy policy are documents intended to help final users understand the handling given to their data after they’ve been collected. Through them the user is questioned or informed about collected information, it’s usage, retention time or even dissemination. The OpenID Connect, which has some Open Source implementations and is based on OAuth 2.0, aims on guarantee authentication and authorization between a user and the desired service. For such, it provides end-user information in form of a token containing basic information about the user’s profile. Through this paper an extension to a OpenID Connect identity provider was implemented, allowing the transmission of privacy policies on service utilization context, together with basic user information incorporated on token. By that, the context of Sticky Policies is used, which adds the privacy policies to the user data normally sent by the OpenID protocol, allowing a user to have control upon application and propagation of it’s data while using a service

Local roughness exponent in the nonlinear molecular-beam-epitaxy universality class in one-dimension

We report local roughness exponents, $\alpha_{\text{loc}}$, for three interface growth models in one dimension which are believed to belong the non-linear molecular-beam-epitaxy (nMBE) universality class represented by the Villain-Lais-Das Sarma (VLDS) stochastic equation. We applied an optimum detrended fluctuation analysis (ODFA) [Luis et al., Phys. Rev. E 95, 042801 (2017)] and compared the outcomes with standard detrending methods. We observe in all investigated models that ODFA outperforms the standard methods providing exponents in the narrow interval $\alpha_{\text{loc}}\in[0.96,0.98]$ consistent with renormalization group predictions for the VLDS equation. In particular, these exponent values are calculated for the Clarke-Vvdensky and Das Sarma-Tamborenea models characterized by very strong corrections to the scaling, for which large deviations of these values had been reported. Our results strongly support the absence of anomalous scaling in the nMBE universality class and the existence of corrections in the form $\alpha_{\text{loc}}=1-\epsilon$ of the one-loop renormalization group analysis of the VLDS equation