scholarly journals Trading-Off Local versus Global Effects of Regression Nodes in Model Trees

2002 ◽  
pp. 393-402 ◽  
Author(s):  
Donato Malerba ◽  
Annalisa Appice ◽  
Michelangelo Ceci ◽  
Marianna Monopoli
Keyword(s):  
Model Trees

scholarly journals Top-down induction of model trees with regression and splitting nodes

2004 ◽  
Vol 26 (5) ◽  
pp. 612-625 ◽  
Author(s):  
D. Malerba ◽  
F. Esposito ◽  
M. Ceci ◽  
A. Appice
Keyword(s):  
Top Down ◽  
Model Trees

Responses of tsetse flies (Diptera: Glossinidae) to odour-baited trees

1991 ◽  
Vol 81 (3) ◽  
pp. 323-331 ◽  
Author(s):  
G. A. Vale
Keyword(s):  
Field Studies ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Free Standing ◽  
Model Trees ◽  
Clear Effect

AbstractField studies in Zimbabwe elucidated how trees might be enhanced as baits for controlling Glossina morsitans morsitans Westwood and G. pallidipes Austen. Catches from electrocuting devices at the bases of trees were near nil when sampling tsetse flies landing on the trunk but much greater when sampling them flying within 1 m of the trunk. Catches increased 5–8 times when 2 m2 of the trunk were blackened and given odour of acetone, 1-octen-3-ol, 3-n-propyl phenol and 4-methyl phenol, but were still only ca. 30% of the catches from an odour-baited, free-standing, 1 × 1 m screen of black cloth. The upright trunk of real and model trees hindered their attractiveness but leaves and branches 5 m above ground had no clear effect. Real and artificial stumps of trees were as effective as the screen if they were 1 m2, compact and sharply outlined. The practical and biological implications of the results are discussed, with particular reference to the use of insecticide-treated netting with modified tree stumps as baits for control.

scholarly journals Towards global empirical upscaling of FLUXNET eddy covariance observations: validation of a model tree ensemble approach using a biosphere model

2009 ◽  
Vol 6 (3) ◽  
pp. 5271-5304 ◽  
Author(s):  
M. Jung ◽  
M. Reichstein ◽  
A. Bondeau
Keyword(s):  
Eddy Covariance ◽  
Learning Algorithm ◽  
Gross Primary Production ◽  
Global Network ◽  
Data Set ◽  
Model Trees ◽  
Ensemble Approach ◽  
Model Tree ◽  
Biosphere Model ◽  
Variance Explained

Abstract. Global, spatially and temporally explicit estimates of carbon and water fluxes derived from empirical up-scaling eddy covariance measurements would constitute a new and possibly powerful data stream to study the variability of the global terrestrial carbon and water cycle. This paper introduces and validates a machine learning approach dedicated to the upscaling of observations from the current global network of eddy covariance towers (FLUXNET). We present a new model TRee Induction ALgorithm (TRIAL) that performs hierarchical stratification of the data set into units where particular multiple regressions for a target variable hold. We propose an ensemble approach (Evolving tRees with RandOm gRowth, ERROR) where the base learning algorithm is perturbed in order to gain a diverse sequence of different model trees which evolves over time. We evaluate the efficiency of the model tree ensemble approach using an artificial data set derived from the the Lund-Potsdam-Jena managed Land (LPJmL) biosphere model. We aim at reproducing global monthly gross primary production as simulated by LPJmL from 1998–2005 using only locations and months where high quality FLUXNET data exist for the training of the model trees. The model trees are trained with the LPJmL land cover and meteorological input data, climate data, and the fraction of absorbed photosynthetic active radiation simulated by LPJmL. Given that we know the "true result" in the form of global LPJmL simulations we can effectively study the performance of the model tree ensemble upscaling and associated problems of extrapolation capacity. We show that the model tree ensemble is able to explain 92% of the variability of the global LPJmL GPP simulations. The mean spatial pattern and the seasonal variability of GPP that constitute the largest sources of variance are very well reproduced (96% and 94% of variance explained respectively) while the monthly interannual anomalies which occupy much less variance are less well matched (41% of variance explained). We demonstrate the substantially improved accuracy of the model tree ensemble over individual model trees in particular for the monthly anomalies and for situations of extrapolation. We estimate that roughly one fifth of the domain is subject to extrapolation while the model tree ensemble is still able to reproduce 73% of the LPJmL GPP variability here. This paper presents for the first time a benchmark for a global FLUXNET upscaling approach that will be employed in future studies. Although the real world FLUXNET upscaling is more complicated than for a noise free and reduced complexity biosphere model as presented here, our results show that an empirical upscaling from the current FLUXNET network with a model tree ensemble is feasible and able to extract global patterns of carbon flux variability.

scholarly journals SEED PRODUCTIVITY AND DEVELOPMENT OF PLANTLETS POPULUS × JRTYSCHENSIS CH. Y. YANG

2019 ◽  
pp. 51-57
Author(s):  
B. V. Proshkin ◽  
A. V. Klimov
Keyword(s):  
Filter Paper ◽  
Fruit Set ◽  
Control Group ◽  
Natural Hybrid ◽  
Seed Productivity ◽  
Model Trees ◽  
Fruit Number ◽  
Black Poplar ◽  
Petri Dishes ◽  
Number Of Seeds

The research explores the seed productivity and plantlets growth in the free pollination of the natural hybrid taxon P. × jrtyschensis. Fruits of P. × jrtyschensis were selected from four plants that grow in the collection ofResearchCenter“EducationalBotanical Garden” ofKemerovoStateUniversity. Four P. nigra model trees, randomly selected from theTomRiverfloodplain population, were applied as a control group. The authors used 30 fruit-bearing amentumsfrom each model. The researchers measured set of fruit (capsule); number of ovules per fruit; number of seeds per fruit; set of seeds.. Laboratory germination was determined by sowing Petri dishes on wet filter paper. The authors found out sowing germination by sowing 100 seeds in a box with soil and drainage. The energy of germination was determined on the second day while germination - on the fifth day. P. × jrtyschensis is characterized by a lower level of seed productivity (15-30%) compared to P. nigra. In terms of laboratory germination of seeds, the descendants of hybrids surpassed many P. nigra models, but their soil germination was 20-30% lower than that of black poplar. The observed variability in reproductive indices of both P. × jrtyschensis and P. nigra is mainly caused by specific features of their genotypes. Plantlets being developed, the authors observed no significant differences among the descendants of P. nigra and hybrids. The researchers highlighted plantlets that can stop growing and even more abnormal plants with one, three or four seeds in P. × jrtyschensis. This may be caused by underdevelopment of hypocotyl or germ root. The authors observed breaches in development of P. nigra just once. They outline high plantlets destruction when sowing hybrids on the first day after germination The share of destructed plants within a month (from the beginning of the experiment) reaches 66,0 %, and in P. nigra it does not exceed 40,0 %.

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