2,419 research outputs found

    Modeling Epistemological Principles for Bias Mitigation in AI Systems: An Illustration in Hiring Decisions

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    Artificial Intelligence (AI) has been used extensively in automatic decision making in a broad variety of scenarios, ranging from credit ratings for loans to recommendations of movies. Traditional design guidelines for AI models focus essentially on accuracy maximization, but recent work has shown that economically irrational and socially unacceptable scenarios of discrimination and unfairness are likely to arise unless these issues are explicitly addressed. This undesirable behavior has several possible sources, such as biased datasets used for training that may not be detected in black-box models. After pointing out connections between such bias of AI and the problem of induction, we focus on Popper's contributions after Hume's, which offer a logical theory of preferences. An AI model can be preferred over others on purely rational grounds after one or more attempts at refutation based on accuracy and fairness. Inspired by such epistemological principles, this paper proposes a structured approach to mitigate discrimination and unfairness caused by bias in AI systems. In the proposed computational framework, models are selected and enhanced after attempts at refutation. To illustrate our discussion, we focus on hiring decision scenarios where an AI system filters in which job applicants should go to the interview phase

    Meat yield of Bolinus brandaris (Gastropoda: Muricidae): comparative assessment of the influence of sex, size and reproductive status

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    The present study assessed the influence of sex, size and reproductive status on the meat yield (soft tissues proportion) of the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (southern Portugal). During one year of monthly sampling (October 2008-September 2009), average meat yield of B. brandaris was 40.5 +/- 6.1% (range: 25.8-56.1% wet weight), with no significant differences between sexes. Relationships established between specimen size and soft parts weight indicated that both shell length and total weight are excellent indicators of meat yield. Significant differences in meat yield between size classes further reinforced the trend of increasing meat yield during ontogeny. Meat yield exhibited significant monthly variation and a similar temporal trend in both sexes, which were directly related to the reproductive status. Meat yield of B. brandaris was compared with that of other muricid species and the marked influence of the reproductive status on meat yield prompted a comparative assessment of the spawning season and peak of three sympatric muricids (B. brandaris, Hexaplex trunculus and Stramonita haemastoma). Overall, these findings have implications at diverse levels, including the management, regulation and inspection of this fishing/ harvesting activity and the commercialization and consumption of this seafood product.postdoctoral grant [SFRH/BPD/26348/2006]; Fundacao para a Ciencia e Tecnologia (FCT - Portugal); Fisheries Operational Programme (PROMAR); European Fisheries Fund [EFF 2007-2013]info:eu-repo/semantics/publishedVersio

    Can a Habit Formation Model really explain the forward premium anomaly?

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    Verdelhan (2009) shows that if one is to explain the foreign exchange forwardpremium behavior using Campbell and Cochrane (1999)'s habit formation modelone must specify it in such a way to generate pro-cyclical short term risk free rates.At the calibration procedure, we show that this is only possible in Campbell andCochrane's framework under implausible parameters speci cations given that theprice-consumption ratio diverges in almost all parameters sets. We, then, adoptVerdelhan's shortcut of xing the sensivity function (st) at its steady state level toattain a nite value for the price-consumption ratio and release it in the simulationstage to ensure pro-cyclical risk free rates. Beyond the potential inconsistenciesthat such procedure may generate, as suggested by Wachter (2006), with pro-cyclical risk free rates the model generates a downward sloped real yield curve,which is at odds with the data.

    Continuous cultures of Clostridium acetobutylicum: culture stability and low-grade glycerol utilisation

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    Continuous cultures of two strains of Clostridium acetobutylicum were stable for over 70 d when grown on glucose/ glycerol mixtures. Butanol was the major fermentation end-product, accounting for 43 to 62% (w/w) of total products. Low-grade glycerol [65% (w/v) purity] could replace commercial glycerol [87% (w/v) purity], leading to a similar fermentation pattern: a butanol yield of 0.34 (mol/mol), a butanol productivity of 0.42 g l−1 h−1 and a 84% (w/w) glycerol consumptionwere attained when cultures were grown at pH 6 and D = 0.05 h−1; butanol accounted for 94% (w/w) of total solvents. These values are among the highest reported in literature for C. acetobutylicum simple chemostats

    Correlation Between the Water Drinking Test and Modified Diurnal Tension Curve in Untreated Glaucomatous Eyes

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    OBJECTIVES: To investigate the correlation and agreement between the intraocular pressure peaks detected during the water drinking test and the modified diurnal tension curve in untreated glaucomatous eyes. INTRODUCTION: It has been suggested that the intraocular pressure peaks detected during the water drinking test predict the peaks observed during a 24-hour diurnal tension curve. A more feasible and practical test for assessing intraocular pressure peaks in glaucomatous eyes during office hours would be of great clinical utility. METHODS: This was a prospective study involving open angle glaucoma patients without anti-glaucoma medication submitted to the modified diurnal tension curve and water drinking test on the same day. The intraocular pressure peaks during the water drinking test and the modified diurnal tension curve were reported and compared. Statistical analysis was performed to assess the correlation and agreement between intraocular pressure peak measurements. RESULTS: The correlation between intraocular pressure peaks during the water drinking test and modified diurnal tension curve was significant and strong (Pearson's Correlation Coefficient r=0.780, p<0.0001). Limited agreement was observed between these measurements. Eighty-two percent of intraocular pressure peaks were higher during the water drinking test than the modified diurnal tension curve. DISCUSSION: These findings suggest that the water drinking test may be used as tool to assess risk factors for glaucomatous patients. CONCLUSION: Intraocular pressure peaks detected during the water drinking test could be used in clinical practice to both estimate the peaks observed during the modified diurnal tension curve and assess the status of the eye's outflow facility

    ESTIMATING POTENTIAL OUTPUT AND THE OUTPUT GAP FOR BRAZIL

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    This paper aims to estimate output gap for Brazilian economy through di.erents methodolies. We use traditional univariate techniques and propose a new semi-estructural methodology that combines HP filtering and the production function approach. In order to compare the di.erent potential output estimates, we use a Phillips curve to predict free price inflation and a rolling forecast experiment as a test of forecast accuracy. Our results shows that the forecasts produced by the Local level and Watson models are even more inaccurate than those generated by the simplest univariate models. The main evidence is that the Beveridge-Nelson methodology outperforms all the models at all forecast horizons.
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