2,614 research outputs found
Log Skeletons: A Classification Approach to Process Discovery
To test the effectiveness of process discovery algorithms, a Process
Discovery Contest (PDC) has been set up. This PDC uses a classification
approach to measure this effectiveness: The better the discovered model can
classify whether or not a new trace conforms to the event log, the better the
discovery algorithm is supposed to be. Unfortunately, even the state-of-the-art
fully-automated discovery algorithms score poorly on this classification. Even
the best of these algorithms, the Inductive Miner, scored only 147 correct
classified traces out of 200 traces on the PDC of 2017. This paper introduces
the rule-based log skeleton model, which is closely related to the Declare
constraint model, together with a way to classify traces using this model. This
classification using log skeletons is shown to score better on the PDC of 2017
than state-of-the-art discovery algorithms: 194 out of 200. As a result, one
can argue that the fully-automated algorithm to construct (or: discover) a log
skeleton from an event log outperforms existing state-of-the-art
fully-automated discovery algorithms.Comment: 16 pages with 9 figures, followed by an appendix of 14 pages with 17
figure
On the link between rotation, chromospheric activity and Li abundance in subgiant stars
The connection rotation-CaII emission flux-lithium abundance is analyzed for
a sample of bona fide subgiant stars, with evolutionary status determined from
HIPPARCOS trigonometric parallax measurements and from the Toulouse-Geneva
code.Comment: 9 pages, 8 figure
On the nature of Lithium-rich giant stars: constraints from Beryllium abundances
We have derived beryllium abundances for 7 Li-rich giant (A(Li) > 1.5) stars
and 10 other Li-normal giants, with the aim of investigating the origin of the
Lithium in the Li-rich giants. In particular, we test the predictions of the
engulfment scenario proposed by Siess & Livio (1999), where the engulfment of a
brown dwarf or one or more giant planets would lead to a simultaneous
enrichment of 7Li and 9Be. We show that regardless their nature, none of the
stars studied in this paper were found to have detectable beryllium. Using
simple dilution arguments we show that the engulfment of an external object as
the sole source of Li enrichment is ruled out by the Li and Be abundance data.
The present results favor the idea that Li has been produced in the interior of
the stars by a Cameron-Fowler process and brought up to the surface by an extra
mixing mechanism.Comment: Accepted in A&
The use of linear programming to evaluate the impact of credit for investments in small goat farms.
The use of linear programming to evaluate the impact of credit for investments in small goat farms.
Abstract: The PRONAF is a governmental program that subsidies the credit for investment to smallholder farming and improves the social development in Brazil. This research was carried out to evaluate the effect of increasing the values of credit for investment used for the PRONAF farmers in semi-arid areas, and their impact in the income and labor in smallholder farming production system. Economic data of dairy and meat goat systems of PRONAF farmers in ?Rio Grande do Norte?, Brazil was used. The limit of the model was the credit for investment, maximum number of animals in the system and the labor time. The current values of credit for investment (US$ 2,850.00) were increased by 25%, 50% and 100% and its impact analyzed in the farm income when considering milk and meat production. The maximum number of animals in the system was estimated by multiplying the carry capacity (1.5 heads/ha/year) plus the average pasture areas of PRONAF farms (35 ha). The maximum labor time, available for farm work, was 12 hours/day. This mathematical model was solved using linear programming with LINDO® software. When the credit for investment was expanded in 25 and 50%, the income of the system increased, respectively, to 22 and 41%. It happened because the values of credit allowed increasing the number of dairy goats in the system. However, this income was not enough to use and pay more than 5 hours/day in dairy goat system activities. When raising the credit for investment up to 100% it could increase the income of the system around 81%. It happened because the number of dairy goats grew up to 83% and the dairy production had better results than meat production. The system with more dairy goats produces enough income as to pay the farmer labor (7 hours/day) and during the other five hours could develop other activities. Therefore, the results of the analysis indicated that an increase in the credit for investment in small goat farms in semi-arid areas in Brazil could be addressed towards the dairy goat production, enhancing the income of families and employment opportunities.Edição de proceedings 9th International Goat Conference; 23th Conference ofthe Asociación Mexicana de Producción Caprinaat Queretaro, Mexico, in September 2008. XXIII Conference ofthe Asociación Mexicana de Producción Caprin
How can one probe Podolsky Electrodynamics?
We investigate the possibility of detecting the Podolsky generalized
electrodynamics constant . First we analyze an ion interferometry apparatus
proposed by B. Neyenhuis, et al (Phys. Rev. Lett. 99, (2007) 200401) who looked
for deviations from Coulomb's inverse-square law in the context of Proca model.
Our results show that this experiment has not enough precision for measurements
of . In order to set up bounds for we investigate the influence of
Podolsky's electrostatic potential on the ground state of the Hydrogen atom.
The value of the ground state energy of the Hydrogen atom requires Podolsky's
constant to be smaller than 5.6 fm, or in energy scales larger than 35.51 MeV.Comment: 12 pages, 2 figure
Avaliação de linhagens de arroz irrigado em Roraima com tipo de grão para a culinária japonesa.
Em Roraima, o cultivo do arroz representa uma das poucas cadeias produtivas efetivamente estabilizadas, com produção suficiente para abastecer o mercado interno e permitir exportação para outros Estados. No entanto, as agroindústrias locais que comercializam, basicamente, o arroz branco de classe longo-fino, podem ter na diversificação de tipos de grãos, como os demandados para a culinária japonesa, uma oportunidade de verticalização da produção e aumento de renda, já que o preço desse produto chega a ser,em média, duas a três vezes superior ao tipo local. Assim, o objetivo deste trabalho foi avaliar o desempenho produtivo de linhagens de arroz irrigado com tipo de grãos para a culinária japonesa, nas condições de cultivo de Roraima. Foram avaliadas,no perÃodo de dezembro de 2003 a março de 2004, 10 linhagens de arroz irrigado em delineamento experimental de blocos ao acaso com quatro repetições. Além de caracterÃsticas agronômicas, foi avaliada a qualidade dos grãos. Foram realizadas análises de variância e para a comparação das estimativas das médias dos tratamentos foi aplicado o teste de Tukey em nÃvel de 5% de probabilidade. A linhagem de arroz irrigado CNAi 9903 mostrou-se como a mais adequada para uso na culinária japonesa e apresentou boa produtividade e adaptação à s condições de cultivo em Roraima.bitstream/item/28411/1/bp142009.pd
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