FCT: CMA - Documentos de conferências internacionais
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- Evaluation of the sugar content along the stalk height of sugarcane plants for different growth conditionsPublication . Mateus, Dina M. R.; Pinho, Henrique J. O.; Grilo, Luís M.; CMA - Centro de Matemática e AplicaçõesThe Brix degree is an indicator of sugarcane juice sugar content but it is not uniform along the plant stalk height. To evaluate the Brix on the height measurement of the stalk, three groups of sugarcane samples were compared. The groups consisted in different growth conditions under Portuguese mainland climate: (i) growth in a constructed wetland filled with clay brick fragments used to treat secondary wastewater; (ii) growth in a deactivated but irrigated constructed wetland filled with clay lightweight aggregate; (iii) growth in soil with irrigation. Some descriptive statistics were obtained for the three groups and 95% confidence intervals (also including bootstrap BCa procedure) were computed and compared. The one-way ANOVA demonstrates that different growth conditions do not affect the relative height position of the stalk average Brix representative internode. A simple linear regression was adjusted to model the relationship between the relative Brix with the relative measurement height and might be used to predict the sugarcane juice sugar content.
- Context-free word problem semigroupsPublication . Brough, Tara; Cain, Alan J.; Pfeiffer, Markus; CMA - Centro de Matemática e AplicaçõesThis paper studies the classes of semigoups and monoids with context-free and deterministic context-free word problem. First, some examples are exhibited to clarify the relationship between these classes and their connection with the notions of word-hyperbolicity and automaticity. Second, a study is made of whether these classes are closed under applying certain semigroup constructions, including direct products and free products, or under regressing from the results of such constructions to the original semigroup(s) or monoid(s).
- Randomized sample size F tests for the one-way layoutPublication . Mexia, João T.; Moreira, Elsa E.; CMA - Centro de Matemática e AplicaçõesDistributions and densities for F test statistics are obtained assuming random sample sizes, thus getting random degrees of freedom and non-centrality parameters. Classical optimum properties are extended to this new setup as well as Scheffé Theorem for simultaneous confidence intervals.