A simulation model to evaluate the impact of environmental programmes on dairy farms

2000 ◽  
Vol 7 (2) ◽  
pp. 171-183 ◽  
Author(s):  
G. Huylenbroeck ◽  
G. Jacobs ◽  
P. Vanrolleghem
Keyword(s):  
Simulation Model ◽  
Dairy Farms ◽  
The Impact

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Prevalence of mastitis in Nigerian livestock: a Review

2020 ◽  
Vol 1 (1) ◽  
pp. 20-29
Author(s):  
Hussaini Ojagefu Adamu ◽  
Rahimat Oshuwa Hussaini ◽  
Cedric Obasuyi ◽  
Linus Irefo Anagha ◽  
Gabriel Oscy Okoduwa
Keyword(s):  
Control Strategies ◽  
Dairy Farms ◽  
Livestock Production ◽  
Sub Saharan Africa ◽  
Economic Losses ◽  
Ecological Development ◽  
Management Plans ◽  
Sub Saharan ◽  
Control And Management ◽  
The Impact

AbstractMastitis is a disease of livestock that directly impede livestock production and thus hindering the socio-ecological development of sub-Saharan Africa. Studies have estimated the prevalence of this disease in 30% of Africa countries, with Ethiopia having the highest prevalence. The coverage is low, despite the wide livestock and dairy farms distribution in Africa. Furthermore, estimated economic losses due to the impact of mastitis are lacking in Nigeria. The disease is endemic in Nigeria as indicated by the available data and there are no proposed management plans or control strategies. This review is thus presented to serve as a wakeup call to all parties involved to intensify efforts towards the diagnosis, control, and management of the disease in Nigeria.

scholarly journals System Level Simulation of Microgrid Power Electronic Systems

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 644
Author(s):  
Michal Frivaldsky ◽  
Jan Morgos ◽  
Michal Prazenica ◽  
Kristian Takacs
Keyword(s):  
Smart Grid ◽  
Simulation Model ◽  
Real Time ◽  
Power Converter ◽  
System Level ◽  
Time Behavior ◽  
Operational Parameters ◽  
System Level Simulation ◽  
Time Operation ◽  
The Impact

In this paper, we describe a procedure for designing an accurate simulation model using a price-wised linear approach referred to as the power semiconductor converters of a DC microgrid concept. Initially, the selection of topologies of individual power stage blocs are identified. Due to the requirements for verifying the accuracy of the simulation model, physical samples of power converters are realized with a power ratio of 1:10. The focus was on optimization of operational parameters such as real-time behavior (variable waveforms within a time domain), efficiency, and the voltage/current ripples. The approach was compared to real-time operation and efficiency performance was evaluated showing the accuracy and suitability of the presented approach. The results show the potential for developing complex smart grid simulation models, with a high level of accuracy, and thus the possibility to investigate various operational scenarios and the impact of power converter characteristics on the performance of a smart gird. Two possible operational scenarios of the proposed smart grid concept are evaluated and demonstrate that an accurate hardware-in-the-loop (HIL) system can be designed.

scholarly journals A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works

2021 ◽  
Vol 13 (11) ◽  
pp. 5795
Author(s):  
Sławomir Biruk ◽  
Łukasz Rzepecki
Keyword(s):  
Simulation Model ◽  
Technological Process ◽  
Construction Projects ◽  
Working Time ◽  
Simulation Studies ◽  
Construction Methods ◽  
The Impact ◽  
Construction Works

Reducing the duration of construction works requires additional organizational measures, such as selecting construction methods that assure a shorter realization time, engaging additional resources, working overtime, or allowing construction works to be performed simultaneously in the same working units. The simultaneous work of crews may affect the quality of works and the efficiency of construction processes. This article presents a simulation model aimed at assessing the impact of the overlap period on the extension of the working time of the crews and the reduction of a repetitive project’s duration in random conditions. The purpose of simulation studies is to provide construction managers with guidelines when deciding on the dates of starting the sequential technological process lines realized by specialized working crews, for sustainable scheduling and organization of construction projects.

scholarly journals Optimising pasture and grazing management decisions on the Cicerone Project farmlets over variable time horizons

2013 ◽  
Vol 53 (8) ◽  
pp. 796 ◽  
Author(s):  
Karl Behrendt ◽  
Oscar Cacho ◽  
James M. Scott ◽  
Randall Jones
Keyword(s):  
Simulation Model ◽  
Strategic Decision ◽  
Stochastic Dynamic ◽  
Economic Returns ◽  
Strategic Decisions ◽  
Trade Offs ◽  
Using Data ◽  
Time Frames ◽  
The Impact ◽  
Stocking Rates

This study addresses the problem of balancing the trade-offs between the need for animal production, profit, and the goal of achieving persistence of desirable species within grazing systems. The bioeconomic framework applied in this study takes into account the impact of climate risk and the management of pastures and grazing rules on the botanical composition of the pasture resource, a factor that impacts on livestock production and economic returns over time. The framework establishes the links between inputs, the state of the pasture resource and outputs, to identify optimal pasture development strategies. The analysis is based on the application of a dynamic pasture resource development simulation model within a seasonal stochastic dynamic programming framework. This enables the derivation of optimum decisions within complex grazing enterprises, over both short-term tactical (such as grazing rest) and long-term strategic (such as pasture renovation) time frames and under climatic uncertainty. The simulation model is parameterised using data and systems from the Cicerone Project farmlet experiment. Results indicate that the strategic decision of pasture renovation should only be considered when pastures are in a severely degraded state, whereas the tactical use of grazing rest or low stocking rates should be considered as the most profitable means of maintaining adequate proportions of desirable species within a pasture sward. The optimal stocking rates identified reflected a pattern which may best be described as a seasonal saving and consumption cycle. The optimal tactical and strategic decisions at different pasture states, based on biomass and species composition, varies both between seasons and in response to the imposed soil fertility regime. Implications of these findings at the whole-farm level are discussed in the context of the Cicerone Project farmlets.

scholarly journals Experimental Study on Limestone Cohesive Particle Model and Crushing Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Huaiying Fang ◽  
Dawei Xing ◽  
Jianhong Yang ◽  
Fulin Liu ◽  
Junlong Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Simulation Model ◽  
Impact Velocity ◽  
Distribution Curve ◽  
Particle Model ◽  
Particle Sizes ◽  
Particle Crushing ◽  
Discrete Element Method Simulation ◽  
Impact Crushing ◽  
The Impact

This study investigates the effect of impact velocity and particle size on crushing characteristics. We use a discrete-element method simulation and construct cohesive limestone particles with internal microinterfaces and cracks for impact crushing experimentation. The simulation model follows the same process as the impact crushing experiment. Results show that, after crushing at impact velocities of 30 and 40 m/s, the simulated particle-size distribution curve matches experimental results as closely as 95%. For different particle sizes, results are more than 90% in agreement. These results indicate the feasibility of the cohesive-particle crushing simulation model. When the particle size is 15 mm, an approximate linear relationship exists on impact velocity and crushing ratio. For a constant impact velocity, the particle size of 18 mm results in the maximum crushing ratio.

scholarly journals Simulation of marine vehicles operation in the state of wind and wave conditions

2021 ◽  
pp. 191-199
Author(s):  
А.А. Карпенко
Keyword(s):  
Supply Chain ◽  
Simulation Model ◽  
Transport System ◽  
Wind Wave ◽  
Supply Chain System ◽  
Chain System ◽  
Marine Vehicles ◽  
Marine Transport ◽  
The Impact ◽  
The City

Эксплуатация морского транспорта подвержена влиянию множества факторов, учет которого требует высокой трудоемкости. Как правило, моделирование морских транспортных систем, выступающих в роли связующего звена различных экономических процессов, производится на стадии предпроектной разработки. На этой стадии, помимо прочего, необходимо оценить влияние на проектируемую систему не только детерминированных, но и стохастических процессов. В данной работе описан алгоритм учета влияния ветро-волновых режимов морских участков на эксплуатацию морских транспортных судов. Данный алгоритм реализован на примере модели системы поставок сжиженного природного газа (СПГ) морским транспортом потребителям г. Мурманск. Научной новизной данной работы является комплексный подход к логико-математическому описанию эксплуатации морских транспортных средств. Этот подход включает в себя моделирование эксплуатации судна на базе агентного подхода, моделирование ветро-волновых режимов на основе анализа временных рядов и стохастических экспериментов и определение скорости движения судна на основе эмпирико-статистических формул расчета скорости судна и теории гидродинамики судна. В ходе выполнения данной работы была построена имитационная модель поставок СПГ в г. Мурманск морским транспортом. Результаты прогонов этой модели были верифицированы на основе технико-экономического обоснования АО «ЦНИИМФ». Алгоритм построения имитационной модели, описанный в данной работе, может быть применен для имитационного моделирования морских транспортных систем с различными целями функционирования. Marine transport operation is affected by a lot of factors taking into account of which requires a high laboriousness. In most cases modelling of marine transport operation as a link in various economic processes is performed at the pre-design development stage. By the way, evaluation of the impact of both deterministic and stochastic processes on the designed system is necessary at this stage. Evaluation of transport system efficiency based on pre-formed system of criteria is in progress at this stage. This paper describes an algorithm for modeling the operation of marine vessels taking into account wind-wave regime of sea areas. This algorithm is implemented by the model of liquified natural gas (LNG) supply chain system by marine transport to consumers of the city of Murmansk. Scientific novelty of this paper is a complex approach to logical-mathematical description of marine vehicles exploitation. This approach consists of agent-based simulation of vessel exploitation, modelling of wind-wave regimes by means of time series analysis and stochastic modelling and the speed determination of the vessel movement based on the empirical-statistical formulas for calculating the speed of the vessel and the theory of vessel hydrodynamics. During this research simulation model LNG supply chain system by marine transport to consumers of the city of Murmansk was developed. The results of the model have been verified by the feasibility study performed by CNIIMF JSC. The algorithm for constructing simulation model described in this paper could be implemented in modelling of marine transport system for various purposes.

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