An introduction to Extend [hierarchical simulation modelling tool]

Author(s):  
D. Krahl
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.


2020 ◽  
Vol 0 (3) ◽  
pp. 93-99
Author(s):  
M.M. NIZAMUTDINOV ◽  
◽  
A.R. ATNABAEVA ◽  
M.I. AKHMETZYANOVA ◽  
◽  
...  

Author(s):  
Özkan Uğurlu ◽  
Ercan Köse ◽  
Ersan Başar ◽  
Murat Özkök ◽  
Jin Wang

2020 ◽  
Vol 10 (1) ◽  
pp. 224-231
Author(s):  
Erik Tischer ◽  
Petr Nachtigall ◽  
Jaromír Široký

AbstractSimulation modelling is one way to determine the capacity of railway lines. The specialized software tool OpenTrack was used for simulation. The aim of this paper was to find out whether the OpenTrack simulation software can be used for the calculation of headway, and to compare the results with the methodology of the Railway Infrastructure Administration (SŽDC). Using the software tool, a detailed transport network model can be created including all its important characteristics. The simulation follows the movements and behaviour of trains with predefined parameters on the modelled railway line. OpenTrack allows for monitoring a range of parameters including not only train delays, train conflicts and train traffic flow, but also for instance train energy performance and headways. During the first stage of work with OpenTrack, a simulation model was created, not reflecting any existing infrastructure but including parameters typical of railway lines in the Czech Republic, such as the configuration of gridirons, length of station tracks, size of block sections, etc. This model was subsequently used for the simulation of type train set journeys, and a headway calculator was used for the calculation of headway values. These values were compared with the methodology used by the Railway Infrastructure Administration. The paper is concluded by the comparison of the above mentioned approaches.


Author(s):  
M. Ramadass ◽  
J. Rosenberger ◽  
B. Huff ◽  
S. Gonterman ◽  
R.N. Subramanian
Keyword(s):  

2017 ◽  
Vol 35 (9) ◽  
pp. 937-949 ◽  
Author(s):  
Syed Salleh ◽  
Praveen Thokala ◽  
Alan Brennan ◽  
Ruby Hughes ◽  
Andrew Booth

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