120 research outputs found

    The Post-Agreement Negotiation Process: The Problems of Ratifying International Environmental Agreements

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    National ratification of international environmental agreements is a prime example of post-agreement negotiations. It is often the first subprocess in a larger process of sustained negotiations that occur after international accords are concluded, focused on implementation of those accords. Certainly, implementation of negotiated agreements involves legal, political, verification, and enforcement activities at both domestic and international levels. Many of these activities, including ratification, are characterized by negotiations between various stakeholders to reach mutually beneficial and acceptable means to achieve national implementation of, and compliance with, treaty provisions. This paper places ratification negotiations within the larger conceptual context of post-agreement negotiations, with the goal of understanding and explaining problems of treaty compliance. An empirical analysis is conducted to assess the impact of various inherent and situational factors on problems in the ratification process. Ultimately, we are interested in identifying ways of improving the international negotiation process that initiated these later problems in implementation

    Post Negotiation Impasses in the Environmental Domain. The Influence of Some Political and Economic Factors on Environmental Treaty Acceptance

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    This paper assesses some of the implications of certain national economic and political factors on the likelihood and degree of treaty acceptance (ratification, accession, etc.) in the post-agreement negotiation period. The purpose of the study is to analyze the problem of delays in treaty acceptance with a view to suggesting how the negotiation and post-negotiation processes may be restructured so as to facilitate acceptance. The aim is to draw conclusions that have implications for policy making-to highlight what it is in the treaties themselves or in the conditions surrounding them that cause delays in acceptance and subsequent implementation. International environmental agreements entered into by European countries between 1972-1992 are examined in this context. The data set includes 61 multilateral treaties, and the independent sovereign state is the unit of analysis. A literature review identifies what has been done in this area and enables focus on a few specific questions. The following types of variables are operationalized and measured in the study. Dependent Variable: The extent of ratification problems. Measure: Average years to ratify (from adoption to entry into force). Independent Variables: (i) Issue saliency. Measure: R&D expenditure on environmental protection; (ii) Popular pressure. Measure: Public concern on environmental issues at the local, national and international level; (iii) National wealth. Measure: GDP/capita; (iv) Quality of life. Measure: Human Development Index. This paper provides data on the initial step of the post-negotiation or post-agreement cycle, namely acceptance, so as to suggest further directions for investigation and to provide the background for a next phase of research on the behavioral implementation and compliance that follow on acceptance. Some alternatives to ratification discussed in the literature are also presented

    Buyback Problem - Approximate matroid intersection with cancellation costs

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    In the buyback problem, an algorithm observes a sequence of bids and must decide whether to accept each bid at the moment it arrives, subject to some constraints on the set of accepted bids. Decisions to reject bids are irrevocable, whereas decisions to accept bids may be canceled at a cost that is a fixed fraction of the bid value. Previous to our work, deterministic and randomized algorithms were known when the constraint is a matroid constraint. We extend this and give a deterministic algorithm for the case when the constraint is an intersection of kk matroid constraints. We further prove a matching lower bound on the competitive ratio for this problem and extend our results to arbitrary downward closed set systems. This problem has applications to banner advertisement, semi-streaming, routing, load balancing and other problems where preemption or cancellation of previous allocations is allowed

    Advances on Matroid Secretary Problems: Free Order Model and Laminar Case

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    The most well-known conjecture in the context of matroid secretary problems claims the existence of a constant-factor approximation applicable to any matroid. Whereas this conjecture remains open, modified forms of it were shown to be true, when assuming that the assignment of weights to the secretaries is not adversarial but uniformly random (Soto [SODA 2011], Oveis Gharan and Vondr\'ak [ESA 2011]). However, so far, there was no variant of the matroid secretary problem with adversarial weight assignment for which a constant-factor approximation was found. We address this point by presenting a 9-approximation for the \emph{free order model}, a model suggested shortly after the introduction of the matroid secretary problem, and for which no constant-factor approximation was known so far. The free order model is a relaxed version of the original matroid secretary problem, with the only difference that one can choose the order in which secretaries are interviewed. Furthermore, we consider the classical matroid secretary problem for the special case of laminar matroids. Only recently, a constant-factor approximation has been found for this case, using a clever but rather involved method and analysis (Im and Wang, [SODA 2011]) that leads to a 16000/3-approximation. This is arguably the most involved special case of the matroid secretary problem for which a constant-factor approximation is known. We present a considerably simpler and stronger 33e14.123\sqrt{3}e\approx 14.12-approximation, based on reducing the problem to a matroid secretary problem on a partition matroid

    Packing Returning Secretaries

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    We study online secretary problems with returns in combinatorial packing domains with nn candidates that arrive sequentially over time in random order. The goal is to accept a feasible packing of candidates of maximum total value. In the first variant, each candidate arrives exactly twice. All 2n2n arrivals occur in random order. We propose a simple 0.5-competitive algorithm that can be combined with arbitrary approximation algorithms for the packing domain, even when the total value of candidates is a subadditive function. For bipartite matching, we obtain an algorithm with competitive ratio at least 0.5721o(1)0.5721 - o(1) for growing nn, and an algorithm with ratio at least 0.54590.5459 for all n1n \ge 1. We extend all algorithms and ratios to k2k \ge 2 arrivals per candidate. In the second variant, there is a pool of undecided candidates. In each round, a random candidate from the pool arrives. Upon arrival a candidate can be either decided (accept/reject) or postponed (returned into the pool). We mainly focus on minimizing the expected number of postponements when computing an optimal solution. An expected number of Θ(nlogn)\Theta(n \log n) is always sufficient. For matroids, we show that the expected number can be reduced to O(rlog(n/r))O(r \log (n/r)), where rn/2r \le n/2 is the minimum of the ranks of matroid and dual matroid. For bipartite matching, we show a bound of O(rlogn)O(r \log n), where rr is the size of the optimum matching. For general packing, we show a lower bound of Ω(nloglogn)\Omega(n \log \log n), even when the size of the optimum is r=Θ(logn)r = \Theta(\log n).Comment: 23 pages, 5 figure

    Building data warehouses in the era of big data: an approach for scalable and flexible big data warehouses

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    During the last few years, the concept of Big Data Warehousing gained significant attention from the scientific community, highlighting the need to make design changes to the traditional Data Warehouse (DW) due to its limitations, in order to achieve new characteristics relevant in Big Data contexts (e.g., scalability on commodity hardware, real-time performance, and flexible storage). The state-of-the-art in Big Data Warehousing reflects the young age of the concept, as well as ambiguity and the lack of common approaches to build Big Data Warehouses (BDWs). Consequently, an approach to design and implement these complex systems is of major relevance to business analytics researchers and practitioners. In this tutorial, the design and implementation of BDWs is targeted, in order to present a general approach that researchers and practitioners can follow in their Big Data Warehousing projects, exploring several demonstration cases focusing on system design and data modelling examples in areas like smart cities, retail, finance, manufacturing, among others

    Selênio como suplemento para bovinos intoxicados cronicamente por Pteridium sp. no Espirito Santo. 2017.

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    Pteridiumsp.(samambaia) é uma planta responsável por diversos quadros de intoxicação em animais e seres humanos. Em bovinos, um dos quadros comuns na região sul do Espírito Santo é a hematúria enzoótica bovina (HEB) que não possui tratamento. Assim, o objetivo do presente trabalho foi determinar os efeitos do selênio associado a vitamina E como suplemento em animais intoxicados cronicamente pelo Pteridium sp. Foram selecionados 21 animais intoxicados cronicamente pela planta e com HEB. Os animais foram examinados clinicamente e foi realizada a coleta da urina para a confirmação da hematúria. O delineamento experimental foi feito em quatro grupos divididos ao acaso (controle soro fisiológico; tratamento 1 0,05 mg/Kg do suplemento;tratamento20,10mg/Kgdosuplemento;tratamento30,20mg/Kgdo suplemento). Foi feita a suplementação parenteral, via intramuscular, uma vez por semana, durante 13 semanas. Quinzenalmente os animais foram avaliados clinicamente e foram coletadas amostras de sangue para dosagem do selêniosérico. A análise de selênio foi feita nos momentos inicial, antes da suplementação com selênio (M0), após quatro semanas de tratamento (M4), após oito semanas (M8) e após 12 semanas (M12), pelo método de espectrofotometria de absorção atômica. Utilizou-seaanálisedevariância(ANOVA)seguidadotestedeTukeya5%.Verificou-se que houve maior ganho de peso dos animais tratados com selênio em relação ao grupocontrolee,também,entreosgrupos.Aintensidadedahematúriareduziuapartir da sexta semana e houve diferença significativa entre os grupos tratados e o grupo controle, assim como entre os grupos. Houve diferença significativa da concentração sérica de selênio entre os tratamentos. Assim, conclui-se que o selênio associado a vitaminaEcomosuplementoparabovinosintoxicadoscronicamenteporPteridiumsp. no Espirito Santo com quadro de HEB teve efeito dose dependente sobre a melhora doquadroclínicocausandoreduçãodaintensidadedehematúriaeaumentodoganho de pes

    Solving Multi-choice Secretary Problem in Parallel: An Optimal Observation-Selection Protocol

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    The classical secretary problem investigates the question of how to hire the best secretary from nn candidates who come in a uniformly random order. In this work we investigate a parallel generalizations of this problem introduced by Feldman and Tennenholtz [14]. We call it shared QQ-queue JJ-choice KK-best secretary problem. In this problem, nn candidates are evenly distributed into QQ queues, and instead of hiring the best one, the employer wants to hire JJ candidates among the best KK persons. The JJ quotas are shared by all queues. This problem is a generalized version of JJ-choice KK-best problem which has been extensively studied and it has more practical value as it characterizes the parallel situation. Although a few of works have been done about this generalization, to the best of our knowledge, no optimal deterministic protocol was known with general QQ queues. In this paper, we provide an optimal deterministic protocol for this problem. The protocol is in the same style of the 1e1\over e-solution for the classical secretary problem, but with multiple phases and adaptive criteria. Our protocol is very simple and efficient, and we show that several generalizations, such as the fractional JJ-choice KK-best secretary problem and exclusive QQ-queue JJ-choice KK-best secretary problem, can be solved optimally by this protocol with slight modification and the latter one solves an open problem of Feldman and Tennenholtz [14]. In addition, we provide theoretical analysis for two typical cases, including the 1-queue 1-choice KK-best problem and the shared 2-queue 2-choice 2-best problem. For the former, we prove a lower bound 1O(ln2KK2)1-O(\frac{\ln^2K}{K^2}) of the competitive ratio. For the latter, we show the optimal competitive ratio is 0.372\approx0.372 while previously the best known result is 0.356 [14].Comment: This work is accepted by ISAAC 201

    Case Report Traumatic Floating Clavicle: A Case Report and Literature Review

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    Bipolar fracture dislocations of the clavicle are rare injuries, usually the result of high-energy direct trauma. Since the original description by Porral in 1831, only a handful of individual case reports and case series by Beckman and Sanders have been reported in the literature. Management of these injuries has remained controversial ranging from nonoperative to aggressive surgery. We report on the case of a young army cadet who had a fracture of the lateral end of the clavicle, with an anterior dislocation of the sternoclavicular joint. Despite being planned for surgery, at the patients request, it was decided to manage the lesion conservatively with graded physiotherapy. At one-year follow-up, he had full pain-free, functional range of movement of the shoulder. This young high demand patient had a good outcome with conservative management, despite going against the current trend towards surgical treatment. We present this case with a review of the literature, highlighting the various management options for this rare lesion
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