Fundamentals of System Modelling

Author(s):  
Adrian Gambier
Keyword(s):  
2020 ◽  
Vol 82 ◽  
pp. 199-209
Author(s):  
Mike B. Dodd ◽  
Katherine N. Tozer ◽  
Iris Vogeler ◽  
Rose Greenfield ◽  
David R. Stevens ◽  
...  

The improvement in forage quality and quantity of summer-dry hill country pasture resulting from the introduction of clover is well recognised. However, ensuring the persistence of the commonly availablecultivars is challenging, in the face of seasonal moisture stress, intensive grazing, competition from established well-adapted pasture species, low soil fertility and low soil pH – conditions typical of the East Coast of the North Island. Here we quantify the value proposition associated with the introduction of white clover into a case study on a Gisborne sheep and beef farm, using a six-step process. A topographically explicit approach is taken, using an understanding of the underlying spatial variability, based on a combination of soil and pasture measurements, APSIM simulation modelling of pasture growth and farm system modelling of enterprise performance. We show that from a baseline of a typical low-fertility, diverse species hill country pasture, white clover introduction can increase spring and summer forage consumption by 17%, enabling inclusion of an additional 6-month bull finishing enterprise generating a 32% greater carcass weight production and leading to a 49% improvement in farm system EBIT. This represents a positive net present value of over $360,000 for the original investment in white clover establishment into existing pastures.


Author(s):  
Jerome R. Bellegarda ◽  
David C. Farden

1988 ◽  
Vol 53 (10) ◽  
pp. 2377-2384 ◽  
Author(s):  
Roman Řeřicha ◽  
Björg N. Cyvin ◽  
Jon Brunvoll ◽  
Sven J. Cyvin

Normal coordinate analyses including calculations of PED's were performed for C2H4.PtCl3 system modelling Zeise's anion, [(C2H4)PtCl3]-. The wedgewise distorsion of the C2H4 ligand known from the crystallographic data for Zeise's salt, was taken into account. Under these circumstances it was found that the kinematic couplings between the internal ligand and complex framework vibrational modes are rather small. The reliability of some existing assignments of the fundamental frequencies of Zeise's anion is discussed.


2021 ◽  
pp. 113558
Author(s):  
You Cao ◽  
Zhijie Zhou ◽  
Changhua Hu ◽  
Shuaiwen Tang ◽  
Jie Wang

Author(s):  
Ørnulf Jan Rødseth ◽  
Lars Andreas Lien Wennersberg ◽  
Håvard Nordahl

AbstractCurrent guidelines for approval of autonomous ship systems are focused on the ships’ concrete operations and their geographic area. This is a natural consequence of the link between geography and the navigational complexity, but moving the ship to a new area or changing owners may require a costly re-approval. The automotive industry has introduced the Operational Design Domain (ODD) that can be used as a basis for approval. However, the ODD does not include the human control responsibilities, while most autonomous ship systems are expected to be dependent on sharing control responsibilities between humans and automation. We propose the definition of an operational envelope for autonomous ship systems that include the sharing of responsibilities between human and automation, and that is general enough to allow approval of autonomous ship systems in all geographic areas and operations that falls within the envelope. We also show how the operational envelope can be defined using a system modelling language, such as the unified modelling language (UML).


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