The paper deals with calibration of the simulation models of hydraulic part of an irrigation project. Calibrated simulation model can be used in design, reconstruction, enlargement or maintenance of the pressurized irrigation systems. Computer model of the water distribution system is a valuable tool which can assist engineers and planners in analyzing the hydraulic performance of water delivery systems. Calibration of the water distribution model consists in comparison of pressures and flows predicted with observed pressures and flows for known operating conditions (i.e., pump operation, tank levels, pressure-reducing valve settings), and adjustment of the input data for the model to improve agreement between observed and predicted values. In practice, given a set or sets of measured state variables, engineers apply trial and error techniques with their judgment to vary the parameters and accomplish this task. Trial and error techniques are tedious do not guarantee reasonable results. The paper introduces the methodology of determination of calibrated parameters automatically. Described methodology of calibration is based on optimizing procedures using the harmony search approach.
By simulating the actual working conditions of a cable, the temperature variation rule of different measuring points under different load currents was analyzed. On this basis, a three-dimensional finite element model (FEM) was established, and the difference and influence factors between the simulation temperature and the experimental measured value were discussed, then the influence of thermal conductivity on the operating temperature of the conductor layer was studied. Finally, combined with the steady-state thermal conductivity model and the experimental measured data, the relation between thermal conductivity and load current was obtained.
In the existent world of continuous production systems, strong attention has been waged
to anonymous risk that probably generates significant apprehension. The forecast for net
present value is extremely important for any production plant. The objective of this paper
is to implement Monte Carlo simulation technique for perceiving the impact of risk and uncertainty
in prediction and forecasting company’s profitability. The production unit under
study is interested to make the initial investment by installing an additional spray dryer
plant. The expressive values acquied from the Monte Carlo technique established a range of
certain results. The expected net present value of the cash flow is $14,605, hence the frequency
chart outcomes confirmed that there is the highest level of certainty that the company
will achieve its target. To forecast the net present value for the next period, the results
confirmed that there are 50.73% chances of achieving the outcomes. Considering the minimum
and maximum values at 80% certainty level, it was observed that 80% chances exist
that expected outcomes will be between $5,830 and $22,587. The model’s sensitivity results
validated that cash inflows had a greater sensitivity level of 21.1% and the cash inflows for
the next year as 19.7%. Cumulative frequency distribution confirmed that the probability
to achieve a maximum value of $23,520 is 90 % and for the value of $6,244 it is about 10 %.
These validations suggested that controlling the expenditures, the company’s outflows can
also be controlled definitely.
The research into the use of less costly modifications of road links and networks, and changes in the service of road surroundings aimed at ensuring an improvement of through traffic performance in suburban areas, and on roads passing through built-up areas as small localities, with application of simulation model, is presented in this paper. From among possible designs, the authors investigated and presented the effectiveness of two, i.e. implementation of an additional multifunctional median lane in the road cross-section, and construction of service roads with different locations of intersections (end or middle of the road section).
The analysis is focused on the impact of such changes on traffic performance and road safety. The authors analysed travel speed, delay and share of platoon traffic on a uniform sections of the road for different types of road surroundings service. The study presents the results of analyses of road network before and after modification, and the assessment of:
•impact of access points density and level of their use on road traffic
performance,
•impact of driving through road sections in built-up
area on building platoon traffic,
•impact of change in the
cross-section type on traffic performance.
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