Agent-Based Modelling and Sensitivity Analysis by Experimental Design and Metamodelling: An Application to Modelling Regional Structural Change

This paper presents the application of the sensitivity analysis techniques Design of Experiments (DOE) and metamodelling to the agent-based model AgriPoliS, which is a spatial and dynamic simulation model of regional structural change. DOE and metamodelling provide a more systematic analysis of results of complex simulation models. When summarising the results, it becomes clear that interest rates, technical change and managerial ability influence average economic land rent the most.simulation, design of experiments, metamodelling, structural change, Research and Development/Tech Change/Emerging Technologies, C9, C15,

An NMF solution for the Flowgraphs case at the TTC 2013

Software systems are getting more and more complex. Model-driven engineering (MDE) offers ways to handle such increased complexity by lifting development to a higher level of abstraction. A key part in MDE are transformations that transform any given model into another. These transformations are used to generate all kinds of software artifacts from models. However, there is little consensus about the transformation tools. Thus, the Transformation Tool Contest (TTC) 2013 aims to compare different transformation engines. This is achieved through three different cases that have to be tackled. One of these cases is the Flowgraphs case. A solution has to transform a Java code model into a simplified version and has to derive control and data flow. This paper presents the solution for this case using NMF Transformations as transformation engine.Comment: In Proceedings TTC 2013, arXiv:1311.753

An NMF solution for the Petri Nets to State Charts case study at the TTC 2013

Software systems are getting more and more complex. Model-driven engineering (MDE) offers ways to handle such increased complexity by lifting development to a higher level of abstraction. A key part in MDE are transformations that transform any given model into another. These transformations are used to generate all kinds of software artifacts from models. However, there is little consensus about the transformation tools. Thus, the Transformation Tool Contest (TTC) 2013 aims to compare different transformation engines. This is achieved through three different cases that have to be tackled. One of these cases is the Petri Net to State Chart case. A solution has to transform a Petri Net to a State Chart and has to derive a hierarchical structure within the State Chart. This paper presents the solution for this case using NMF Transformations as transformation engine.Comment: In Proceedings TTC 2013, arXiv:1311.7536. arXiv admin note: substantial text overlap with arXiv:1312.034

DOING POLICY IN THE LAB! OPTIONS FOR THE FUTURE USE OF MODEL-BASED POLICY ANALYSIS FOR COMPLEX DECISION-MAKING

For models to have an impact on policy-making, they need to be used. Exploring the relationships between policy models, model uptake and policy dynamics is the core of this article. What particular role can policy models play in the analysis and design of policies? Which factors facilitate (inhibit) the uptake of models by policy-makers? What are possible pathways to further develop modelling approaches to better meet the challenges facing agriculture today? In this paper, we address these issues from three different points of view, each of which should shed some light on the subject. The first point of view discusses models in the framework of complex adaptive systems and uncertainty. The second point of view looks at the dynamic interplay between policies and models using the example of modelling in agricultural economics. The third point of view addresses conditions for a successful application of models in policy analysis.modelling, complexity, participatory modelling, policy analysis, model use, Agricultural and Food Policy, Research Methods/ Statistical Methods,

Structural, efficiency and income effects of direct payments: an analysis of different payment schemes for the German region 'Hohenlohe'

The objective of this paper is to work out some fundamental dynamic effects on agricultural structure, farm incomes, and efficiency that result from decoupled income payments, the transfer of payments together with a progressive payment cut. To do so, we apply the agent-based model AgriPoliS (Agri-cultural Policy Simulator). AgriPoliS is a normative spatial and dynamic model of regional agricul-tural structures that takes account of actions and interactions between a large number of individually acting farms. The model is calibrated to the region 'Hohenlohe' in Baden-Württemberg which is char-acterised by intensive livestock farming on the plains and extensive cattle and dairy farming in more remote valleys. The policy simulations show that impacts on structural change, competitiveness, and income distribution vary greatly depending on how the policy scheme is implemented. If direct pay-ments are completely decoupled from land use (no obligation to farm land) this has significant and lasting effects on the competitiveness of agriculture, structural change, farmers’ incomes and land-use.agricultural policy analysis, agent-based models, decoupling

Containerless preparation of advanced optical glasses: Experiment 77F095

Containerless processing of optical glasses was studied in preparation for space shuttle MEA flight experiments. Ground based investigation, experiment/hardware coordination activities and development of flight experiment and sample characterization plans were investigated. In the ground based investigation over 100 candidate glass materials for space processing were screened and promising compositions were identified. The system of Nb2O5-TiO2-CaO was found to be very rich with containerless glass compositions and as extensive number of the oxides combinations were tried resulting in a glass formation ternary phase diagram. The frequent occurrence of glass formation by containerless processing among the compositions for which no glass formations were previously reported indicated the possibility and an advantage of containerless processing in a terrestrial environment

The agricultural policy simulator (AgriPoliS): an agent-based model to study structural change in agriculture (Version 1.0)

A central criticism common to agricultural economic modelling approaches for policy analysis is that they do not adequately take account of a number of characteristic factors of the agricultural sector. This concerns aspects like the immobility of land, heterogeneity of farms, interactions between farms, space, dynamic adjustment processes as well as dynamics of structural change. In brief, modelling the complexity of the system has not been at the centre of interest. In terms of modelling complex economic systems, an agent-based modelling approach is a suitable approach to quantitatively model and understand such systems in a more natural way. In the same way, this applies to the modelling of agricultural structures. In particular, agent-based models of agricultural structures allow for carrying out computer experiments to support a better understanding of the complexity of agricultural systems, structural change, and endogenous adjustment reactions in response to a policy change. This paper presents the agent-based model AgriPoliS (Agricultural Policy Simulator) which simultaneously considers a large number of individually acting farms, product markets, investment activity, as well as the land market, and a simple spatial representation. The ultimate objective of AgriPoliS is to study the interrelationship of rents, technical change, product prices, investments, production and policies, structural effects resulting from these, the analysis of the winners and losers of agricultural policy as well as the costs and efficiency of various policy measures. -- G E R M A N V E R S I O N: Ein oft genannter Kritikpunkt an vielen agrarökonomischen Politikanalysemodellen ist, dass diese nur ungenügend Bezug nehmen auf Aspekte wie die Immobilität von Boden, Heterogenität der Akteure, Interaktionen zwischen Betrieben, räumliche Bezüge, dynamische Anpassungsprozesse und Strukturwandel. Kurz, die Modellierung komplexer Wirkungszusammenhänge steht weniger oder nicht im Zentrum des Interesses. Agentenbasierte Modelle stellen einen Weg dar, das Verständnis komplexer ökonomischer Zusammenhänge zu verbessern bzw. zu quantifizieren. Insbesondere erlauben sie die Durchführung von einer Vielzahl von Computerexperimenten, mit denen Fragestellungen wie der Zusammenhang zwischen Politikmaßnahmen und Strukturwandel untersucht werden können. Basierend darauf, stellt dieser Beitrag das agentenbasierte Modell AgriPoliS (Agricultural Policy Simulator) vor. AgriPoliS ist ein räumlich-dynamisches Modell einer Agrarstruktur, in dem eine Vielzahl individuell abgebildeter landwirtschaftlicher Unternehmen in einer vereinfacht dargestellten Agrarregion agiert und beispielsweise um begrenzt verfügbare landwirtschaftliche Flächen konkurriert.Agent-based systems,Multi-agent systems,Policy analysis,Structural change,Simulation,Agentenbasierte Systeme,Politikanalyse,Multi-Agentensysteme,Strukturwandel,Simulation

Ein Fremdling erobert das Weserbergland - Das Indische oder Drüsige Springkraut (Impatiens glandulifera)

Dem aufmerksamen Naturbeobachter wird es kaum entgangen sein, dass eine im Kreis Höxter neue Pflanze, ein sogenannter Neubürger oder Neophyt, schon seit geraumer Zeit die Weser und ihre Nebenflüsse, ja auch die Muschelkalkhänge und den Solling, erobert hat und teilweise einige Arten der ehemaligen Hochstaudenflur verdrängt. Wie HÄCKER (1988) nachweisen konnte, verschwinden z. B. an der Weser mannshohe einheimische Pflanzen wie der Knollige Kälberkropf (Chaerophyllum bulbosum), die Krause Distel (Carduus crispus), die Große Klette (Arctium lappa), der Gemeine Beifuß (Artemisia vulgaris) oder das seltenere Fluss-Kreuzkraut (Senecio fluviatilis), die u. a. bisher das Bild dieser beeindruckenden Formation prägten und dem Konkurrenzdruck dieses Neulings nicht mehr gewachsen sind. Anderen Orts ist der Verdrängungswettbewerb ein anderer (HAPPE & WENDLING 2005; HAPPE 2012). Es geht um das Indische oder Drüsige Springkraut, das schon bei geringer Berührung seine reifen Kapseln öffnet und die Samenkörner hinausschleudert (daher Springkraut!). Sein wissenschaftlicher Name ist Impatiens glandulifera ROYLE, ein Balsaminengewächs (Balsaminaceae). Die einjährige Pflanze, 50-200 cm hoch, mit oben verzweigtem, bis 5 cm dickem, glasigen Stängel, ähnelt unserem einheimischen Kräutchen „Rühr-mich-nicht-an“ (Impatiens nolitangere, vgl. lat. impatiens = ungeduldig, nolitangere = rühre nicht an), hat jedoch violette, purpurrote, rosa oder weiße Blüten in aufrechten 2-14-blütigen Trauben, inkl. Sporn 25-40 mm lang. Das Springkraut heißt "drüsig", weil zwischen Blattstiel und -grund kleine, rotspitzige Drüse

Structural change and farm labour adjustments in a dualistic farm structure: a simulation study for the region Nitra in southwest Slovakia

This Discussion Paper explores interactions between structural impediments to labour adjustment, specific labour adjustment patterns and the impacts of differing economical and political frames. Based on the agent-based simulation framework AgriPoliS adjusted to the agricultural structure of the region Nitra in southwest Slovakia, we carry out a range of simulation experiments on the possible interplay between off-farm job opportunities for farm operators, growth in other sectors of the economy, and policy impacts. Results show that free movement of labour between sectors leads to strong adjustments in the agricultural labour force and benefits farms with a growth potential. EU Accession and a subsequent decoupling of payments lead farms to stay in business that would have otherwise left the sector. These farms, however, have a different mix of family and hired labour. -- G E R M A N V E R S I O N: Im vorliegenden Discussion Paper werden die Wirkungszusammenhänge auf landwirtschaftlichen Arbeitsmärkten, die auf ihnen auftretenden Hemmnisse hinsichtlich einer optimalen Allokation des Faktors Arbeit und die spezifischen Anpassungsprozesse unter sich wandelnden politischen und ökonomischen Rahmenbedingungen analysiert. Untersuchungsgegenstand ist die Region Nitra im Südwesten der Slovakei. Die dortige Agrarstruktur wurde zum Zweck der dynamischen Abbildung von Strukturveränderungsprozessen im agentenbasierten Model AgriPoliS rekonstruiert. Mit diesem wurden anschließend einerseits Simulationen zur Abschätzung des Einflusses von variierenden Opportunitätskosten des Faktors Arbeit durchgeführt, des Weiteren wurden die agrarstrukturellen Auswirkungen im Wechselspiel von volkswirtschaftlichem Wachstum und unterschiedlich gestalteten politischen Rahmenbedingungen untersucht. Die Ergebnisse zeigen, dass sich unter der Annnahme eines flexiblen, idealisierten Arbeitsmarktes starke Veränderungen in der Agrarstruktur und hinsichtlich des Einsatzes von Arbeitskräften im Landwirtschaftssektor ergeben würden. Derartige Bedingungen würden insbesondere überdurchschnittlich erfolgreichen Betrieben mit vorhandenem Wachstumspotential zum Vorteil gereichen. Sofern diese Wachstumsbetriebe aus der Gruppe der Einzelunternehmen stammen, zeigt sich, dass diese den steigenden Bedarf an Arbeitskräften durch Fremdarbeitskräfte decken würden. Der Beitritt zur EU und die damit einhergehende Implementierung eines Direktzahlungsregimes bewirkt, dass Betriebe, die ohne die neu geschaffenen Anreize aus dem Sektor ausgeschieden wären, kurz- bis mittelfristig in diesem verbleiben und den Strukturwandel hemmen beziehungsweise verlangsamen.Labour input,structural change,agent-based modelling,agricultural policy analysis,Landwirtschaftliche Beschäftigung,Strukturwandel,Agentenbasierte Modellierung,Politikanalyse