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A statistical model for shutdowns due to air quality control for a copper production decision support system
Khalid Aboura, 2015, original scientific article

Abstract: Background: In the mid-1990s, a decision support system for copper production was developed for one of the largest mining companies in Australia. The research was conducted by scientists from the largest Australian research center and involved the use of simulation to analyze options to increase production of a copper production facility. Objectives: We describe a statistical model for shutdowns due to air quality control and some of the data analysis conducted during the simulation project. We point to the fact that the simulation was a sophisticated exercise that consisted of many modules and the statistical model for shutdowns was essential for valid simulation runs. Method: The statistical model made use of a full year of data on daily downtimes and used a combination of techniques to generate replications of the data. Results: The study was conducted with a high level of cooperation between the scientists and the mining company. This contributed to the development of accurate estimates for input into a support system with an EXCEL based interface. Conclusion: The environmental conditions affected greatly the operations of the production facility. A good statistical model was essential for the successful simulation and the high budget expansion decision that ensued.
Keywords: decision support system, simulation, statistical modelling
Published in DKUM: 28.11.2017; Views: 831; Downloads: 315
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Growth dynamics and reproductive activity of annual shoots in the walnut cultivar 'Elit'
Anita Solar, Mitja Solar, Franci Štampar, 2005, original scientific article

Abstract: An architectural analysis of a fruiting branch in the Slovenian variety 'Elit' was conducted during three successive years. The fruit bearing branch was constructed of a three-year-old parent shoot plus all corresponding two-year-old shoots and annual shoots (1Y). The construction of the bearing branch during the time caused a statistically significant increase in the number of annual shoots. The basal diameter and the length of 1Y significantly depended on a year whereas their angles did not. In spite of decreasing length of 1Y, the number of vegetative buds per shoot increased from the first to the third year of observations. The number of nodes was closely correlated with the length of the shoots. Activity points on the 1Y were most often on the apical two or three nodes, what was expressed by a marked acrotony. The number of active points varied as the tree matured. The ratio fruit bearing 1Y ž total 1Y was 0.47 in year 1; 0.18 in year 2; 0.74 in year 3. It points to the slightly alternance. As the tree grew the number of flowering buds per 1Y as well as the number of female flowers per 1Y increased. The results of the three-year-long research show some growth and development rules in the walnut cultivar 'Elit', however, they do not allow a reliable prediction of the following activities. We assume that this will be possible after another three-year-long analysis, with the help of the Hidden Mark Model.
Keywords: Juglans regia L., tree architecture, fruiting branch, vegetative growth, bearing potentials, shoots, statistical modelling, Hidden Mark Model
Published in DKUM: 13.07.2017; Views: 915; Downloads: 97
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