scholarly journals Heterogeneous Compute Clusters and Massive Environmental Simulations Based on the EPIC Model

Modelling ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 215-224
Author(s):  
Nikolay Khabarov ◽  
Alexey Smirnov ◽  
Juraj Balkovič ◽  
Rastislav Skalský ◽  
Christian Folberth ◽  
...  
Keyword(s):  
Crop Growth ◽  
Management Options ◽  
Epic Model ◽  
Processor Core ◽  
Crop Varieties ◽  
Trade Offs ◽  
Desktop Computers ◽  
Order Of Magnitude ◽  
Original Field ◽  
Environmental Simulations

In recent years, the crop growth modeling community invested immense effort into high resolution global simulations estimating inter alia the impacts of projected climate change. The demand for computing resources in this context is high and expressed in processor core-years per one global simulation, implying several crops, management systems, and a several decades time span for a single climatic scenario. The anticipated need to model a richer set of alternative management options and crop varieties would increase the processing capacity requirements even more, raising the looming issue of computational efficiency. While several publications report on the successful application of the original field-scale crop growth model EPIC (Environmental Policy Integrated Climate) for running on modern supercomputers, the related performance improvement issues and, especially, associated trade-offs have only received, so far, limited coverage. This paper provides a comprehensive view on the principles of the EPIC setup for parallel computations and, for the first time, on those specific to heterogeneous compute clusters that are comprised of desktop computers utilizing their idle time to carry out massive computations. The suggested modification of the core EPIC model allows for a dramatic performance increase (order of magnitude) on a compute cluster that is powered by the open-source high-throughput computing software framework HTCondor.

scholarly journals N Management of European Grasslands: Can the Exchange of Gaseous N Species Be Influenced at the Operational Level?

2001 ◽  
Vol 1 ◽  
pp. 652-657 ◽  
Author(s):  
P. Calanca ◽  
A. Neftel ◽  
J. Fuhrer
Keyword(s):  
Late Summer ◽  
Fertilizer Application ◽  
Effective Control ◽  
Management Options ◽  
Total N ◽  
Model Calculations ◽  
Weather Forecasts ◽  
Grassland Ecosystems ◽  
Order Of Magnitude ◽  
N Management

Grassland ecosystems can be regarded as biochemical reactors in which large amounts of organic nitrogen (N) are converted into inorganic N, and vice versa. If managed in a sustainable manner, grasslands should operate in a quasi steady state, characterized by an almost perfect balance between total N input and output. As a consequence, the exchange of gaseous N species (NH3, NO, NO2, N2O, and N2) between grasslands and the atmosphere is very small compared to the total N turnover. In this study, the effects of two management options (mowing and fertilization) on production and emission of nitrous oxide (N2O) from a grass/clover crop were examined on the basis of observations and model results referring to an experiment carried out on the Swiss Plateau in late summer of 2000. It was found that production and emission of N2O induced by mowing were of the same order of magnitude as those brought about by fertilization, suggesting a possible transfer of N from clover to the soil after defoliation. Emissions were strongly modulated by precipitation on time scales ranging from 1 day to 1 week. This indicates that effective control of N2O emissions through management on a day-to-day basis requires reliable medium-range weather forecasts. Model calculations were not able to reproduce essential characteristics of the emissions. The model slightly overestimated the background emissions, but severely underestimated the emission peaks following fertilizer application, and largely failed to reproduce emission induced by mowing. Shortfalls in the model used for this study were found in relation to the description of soil-water fluxes, soil organic matter, and the physiology of clover.

scholarly journals Identifying integrated options for agricultural climate change mitigation

2014 ◽  
Vol 6 (2) ◽  
pp. 192-211 ◽  
Author(s):  
John Tzilivakis ◽  
Kathleen Lewis ◽  
Andrew Green ◽  
Douglas Warner
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
Effective Means ◽  
Integrated Approach ◽  
Management Options ◽  
Content Type ◽  
Mitigation Options ◽  
Trade Offs ◽  
Environmental Objectives ◽  
Change Mitigation

Purpose – In order to achieve reductions in greenhouse gas (GHG) emissions, it is essential that all industry sectors have the appropriate knowledge and tools to contribute. This includes agriculture, which is considered to contribute about a third of emissions globally. This paper reports on one such tool: IMPACCT: Integrated Management oPtions for Agricultural Climate Change miTigation. The paper aims to discuss these issues. Design/methodology/approach – IMPACCT focuses on GHGs, carbon sequestration and associated mitigation options. However, it also attempts to include information on economic and other environmental impacts in order to provide a more holistic perspective. The model identifies mitigation options, likely economic impacts and any synergies and trade-offs with other environmental objectives. The model has been applied on 22 case study farms in seven Member States. Findings – The tool presents some useful concepts for developing carbon calculators in the future. It has highlighted that calculators need to evolve from simply calculating emissions to identifying cost-effective and integrated emissions reduction options. Practical implications – IMPACCT has potential to become an effective means of provided targeted guidance, as part of a broader knowledge transfer programme based on an integrated suite of guidance, tools and advice delivered via different media. Originality/value – IMPACCT is a new model that demonstrates how to take a more integrated approach to mitigating GHGs on farms across Europe. It is a holistic carbon calculator that presents mitigation options in the context other environmental and economic objectives in the search for more sustainable methods of food production.

Systemic modelling of soil functions under the impact of agricultural management

2020 ◽  
Author(s):  
Sara König ◽  
Ulrich Weller ◽  
Birgit Lang ◽  
Mareike Ließ ◽  
Stefanie Mayer ◽  
...  
Keyword(s):  
Soil Structure ◽  
Water Distribution ◽  
Management Strategies ◽  
Simulation Models ◽  
Crop Growth ◽  
Soil Productivity ◽  
Soil Functions ◽  
Management Options ◽  
Soil Organic Matter Turnover ◽  
The Impact

<p>The increasing demand for food and bio-energy gives need to optimize soil productivity, while securing other soil functions such as nutrient cycling and buffer capacity, carbon storage, biological activity, and water filter and storage. Mechanistic simulation models are an essential tool to fully understand and predict the complex interactions between physical, biological and chemical processes of soil with those functions, as well as the feedbacks between these functions.</p><p>We developed a systemic soil model to simulate the impact of different management options and changing climate on the named soil functions by integrating them within a simplified system. The model operates on a 1d soil profile consisting of dynamic nodes, which may represent the different soil horizons, and integrates different processes including dynamic water distribution, soil organic matter turnover, crop growth, nitrogen cycling, and root growth.</p><p>We present the main features of our model by simulating crop growth under various climatic scenarios on different soil types including management strategies affecting the soil structure. We show the relevance of soil structure for the main soil functions and discuss different model outcome variables as possible measures for these functions.</p><p>Further, we discuss ongoing model extensions, especially regarding the integration of biological processes, and possible applications.</p>

Weed management options in transgenic stacked and non transgenic maize (Zea mays) hybrids-A review

2017 ◽  
Vol 38 (04) ◽  
Author(s):  
K. Sivagamy ◽  
C. Chinnusamy ◽  
P. Parasuraman
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Crop Growth ◽  
Control Programme ◽  
Growth And Yield ◽  
Growth Stages ◽  
Management Options ◽  
Maize Crop ◽  
Weed Growth ◽  
Vigorous Growth

Weeds are generally hardy species having fast growth, deep root system and capable of competing very efficiently with cultivated crops for the available resources and adversely affect the crop growth and yield. Weed management systems that rely on post emergence control assume that crops can tolerate competition for certain periods of time without suffering yield losses. Initial slow growth particularly at early crop growth stages and wider plant spacing of maize crop encourages fast and vigorous growth of weeds. It is of paramount importance that, competition from weeds must be minimized to achieve optimum yield. Among the different weed control methods, chemical method bears many advantages in suppressing weed growth and to get healthy and vigorous crop stand. Non-selective herbicide molecules with a variety of mode of action were discovered, developed and marketed for successful weed control programme.

A fisheries risk-assessment framework to evaluate trade-offs among management options in the presence of time-varying productivity

2012 ◽  
Vol 69 (2) ◽  
pp. 209-223 ◽  
Author(s):  
Jeremy S. Collie ◽  
Randall M. Peterman ◽  
Brett M. Zuehlke
Keyword(s):  
Risk Assessment ◽  
Simulation Models ◽  
Quantitative Information ◽  
The Arctic ◽  
Oncorhynchus Keta ◽  
Time Varying ◽  
Assessment Framework ◽  
Management Options ◽  
Commercial Catch ◽  
Trade Offs

Empirically based simulation models can help fisheries managers make difficult decisions involving trade-offs between harvests and maintaining spawner abundance, especially when data contain uncertainties. We developed such a general risk-assessment framework and applied it to chum salmon ( Oncorhynchus keta ) stocks in the Arctic–Yukon–Kuskokwim region of Alaska, USA. These stocks experienced low abundance in the 1990s, which led to declarations of economic disaster and calls for changes in harvest strategies. Our stochastic model provides decision makers with quantitative information about trade-offs among commercial harvest, subsistence harvest, and spawner abundance. The model included outcome uncertainty (the difference between target and realized spawner abundances) in the subsistence and commercial catch modules. We also used closed-loop simulations to investigate the utility of time-varying management policies in which target spawner abundance changed in response to changes in the Ricker productivity parameter (a), as estimated with a Kalman filter. Time-varying policies resulted in higher escapements and catches and reduced risk across a range of harvest rates. The resulting generic risk-assessment framework can be used to evaluate harvest guidelines for most salmon stocks.

scholarly journals Fisher's preferences and trade-offs between management options

2017 ◽  
Vol 18 (5) ◽  
pp. 795-807 ◽  
Author(s):  
Mike Fitzpatrick ◽  
Christos D Maravelias ◽  
Ole Ritzau Eigaard ◽  
Stephen Hynes ◽  
David Reid
Keyword(s):  
Management Options ◽  
Trade Offs

A decision framework for natural resource management: a case study using plant introductions

2006 ◽  
Vol 46 (11) ◽  
pp. 1397 ◽  
Author(s):  
K. J. Wallace
Keyword(s):  
Resource Management ◽  
Cultural Values ◽  
Natural Resource Management ◽  
Natural Resource ◽  
Management Options ◽  
Plant Introductions ◽  
Trade Offs ◽  
Ecological Risk Assessments ◽  
Benefit Cost ◽  
Analytical Tools

One means of anticipating and, thus, preventing natural resource problems, such as those that may arise from plant introductions, is to use effective decision frameworks. This paper argues that such frameworks are typified by 4 elements. These are clear goals explicitly linked to cultural values, key questions that scope problems and management options, application of appropriate analytical tools, and the connection of authority for decisions with responsibility for outcomes. These elements are explored here. Trade offs are an inevitable part of decisions concerning natural resource management, including those relating to plant introductions. Benefit-cost and multi-criteria decision analyses are useful in this regard, but must be applied using methods that ensure all the relevant cultural values and management options are explored. Some recent proposals concerning the assessment of plant introductions do not always adequately frame decision issues. Ecological risk assessments can be used to define an acceptable level of risk concerning the negative impacts of introducing new biota, and, combined with an appropriate benefit-cost or multi-criteria analysis, provide the suite of analytical tools to make effective decisions concerning plant introductions. Effective decisions are more likely when the authority to make decisions and the responsibility for unforeseen outcomes are closely linked.

scholarly journals Using Value Assessment to Drive PHM System Development in Early Design

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Hulse ◽  
Christopher Hoyle ◽  
Kai Goebel ◽  
Irem Tumer
Keyword(s):  
Health Management ◽  
Cost Model ◽  
Operational Performance ◽  
Design Decision ◽  
Value Assessment ◽  
Design Phase ◽  
Management Options ◽  
Early Design ◽  
Trade Offs ◽  
Early Design Phase

Prognostics and Health Management (PHM) systems have been shown to provide many benefits to the reliability, performance, and life of engineered systems. However, because of trade-offs between up-front design and implementation costs, operational performance, and reliability, it may not be obvious in the early design phase whether one PHM system will be more beneficial to another, or whether a PHM system will provide benefit compared to a traditional reliability approach. These trade-offs make the commitment required to pursue PHM features in the early design phase difficult to justify. In this paper, a cost model incorporating trade-offs among design cost, operational performance, and failure risk is used to provide a comprehensive value comparison of health management options to motivate design decision-making. This approach is then demonstrated in a simple case study comparing the use of a PHM system for condition-based maintenance or diagnostic-based recovery with implementing redundancy and increased inspection in the design. Then it is shown how different model inputs and assumptions result in a different system value (and different design choice from the process), illustrating the usefulness of cost modelling to capture design trade-offs. Using this approach, decisions about pursuing PHM can be made early, enabling the benefits to be fully leveraged in the design process to achieve increased operational resilience.

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