Computable Aggregations

In this paper, we postulate computation as a key element in assuring the consistency of a family of aggregation functions so that such a family of operators can be considered an aggregation rule. In particular, we suggest that the concept of an aggregation rule should be defined from a computational point of view, focusing on the computational properties of such an aggregation, i.e., on the manner in which the aggregation values are computed. The new algorithmic definition of aggregation we propose provides an operational approach to aggregation, one that is based upon lists of variable length and that produces a solution even when portions of data are inserted or deleted. Among other advantages, this approach allows the construction of different classifications of aggregation rules according to the programming paradigms used for their computation or according to their computational complexity

New Zealand's Preferential Trading Arrangements: Implications for the New Zealand Dairy Industry

This paper discusses the economic implications of the preferential trade agreements that New Zealand is currently negotiating, using a computable general equilibrium modelling framework. The New Zealand dairy industry is a particular focus in the results, which come from the GTAP model produced by Purdue University. Results are discussed from the independent simulations of preferential trade agreements between New Zealand and Korea, New Zealand and India, New Zealand and Russia, Belarus and Kazakhstan, New Zealand and the Gulf Cooperation Council, and expansion of the Trans-Pacific Partnership to include Australia, Peru, Viet Nam, Malaysia, and the United States of America.New Zealand, dairy industry, preferential trade agreements, Agribusiness, Land Economics/Use, Production Economics,

Elements of a Theory of Simulation

Unlike computation or the numerical analysis of differential equations, simulation does not have a well established conceptual and mathematical foundation. Simulation is an arguable unique union of modeling and computation. However, simulation also qualifies as a separate species of system representation with its own motivations, characteristics, and implications. This work outlines how simulation can be rooted in mathematics and shows which properties some of the elements of such a mathematical framework has. The properties of simulation are described and analyzed in terms of properties of dynamical systems. It is shown how and why a simulation produces emergent behavior and why the analysis of the dynamics of the system being simulated always is an analysis of emergent phenomena. A notion of a universal simulator and the definition of simulatability is proposed. This allows a description of conditions under which simulations can distribute update functions over system components, thereby determining simulatability. The connection between the notion of simulatability and the notion of computability is defined and the concepts are distinguished. The basis of practical detection methods for determining effectively non-simulatable systems in practice is presented. The conceptual framework is illustrated through examples from molecular self-assembly end engineering.Comment: Also available via http://studguppy.tsasa.lanl.gov/research_team/ Keywords: simulatability, computability, dynamics, emergence, system representation, universal simulato

The impact of domestic and global trade liberalization on five Southern African countries

We compare the impact of alternative domestic and global trade liberalization scenarios on five economies in Southern Africa. The study applies a computable general equilibrium model that employs standardised 12-sector social accounting matrices for Malawi, Mozambique, Tanzania, Zambia, and Zimbabwe. The approach incorporates stylised features such as own-household consumption and marketing margins that are of particular importance when a majority of agricultural producers are not sufficiently integrated into formal markets and thus rely on own production to meet their daily diets. Hence, improved infrastructure implies lower marketing costs and better market integration, which translates to increased production opportunities. The comparison of the results across all five countries reveals that common policy measures have different impacts depending on the underlying economic structures.Trade liberalization Africa. ,Malawi. ,Mozambique. ,Tanzania. ,Zambia. ,Zimbabwe. ,Household consumption. ,Markets. ,Economic policy. ,Social accounting Mathematical models. ,TMD ,

Automata-based Adaptive Behavior for Economical Modelling Using Game Theory

In this chapter, we deal with some specific domains of applications to game theory. This is one of the major class of models in the new approaches of modelling in the economic domain. For that, we use genetic automata which allow to build adaptive strategies for the players. We explain how the automata-based formalism proposed - matrix representation of automata with multiplicities - allows to define semi-distance between the strategy behaviors. With that tools, we are able to generate an automatic processus to compute emergent systems of entities whose behaviors are represented by these genetic automata

Impact of Switching Production to Bioenergy Crops: The Switchgrass Example January 2005

This paper reports the results of a series of simulations that evaluate the general equilibrium effects of substituting crude oil by biomass, specifically switchgrass, in the production of petroleum in the USA. The simulations are inspired by debates over the implications for developing countries if agricultural policies in the USA are changed so that agricultural land is transferred from the production of cereals and other crops to biomass production. The results confirm expectations that such a policy shift would raise cereal and other agricultural prices, due to a general reduction in food production in the USA. However, the reduction in the demand for crude oil in the USA causes terms of trade effects that more than offset any potential benefits for developing countries due to the depreciation of their exchange rates, causing a general decline in economic welfare. Moreover, the declines in welfare are proportionately greater for developing countries due to their small levels of production of the commodities whose prices increase with the change in USA agricultural production

Meta-Analysis of General and Partial Equilibrium Simulations of Doha Round Outcomes

Quantification of welfare changes due to trade liberalisation play a crucial role for political decision making. However, meaningful comparisons of simulation results from different sources are difficult. Often significant differences in simulated gains from liberalisation do not serve to increase confidence in quantitative assessments based on trade models. We employ a metaanalysis of applied trade simulations under the WTO Doha Round to identify model characteristics that influence the magnitude of simulation results, and to estimate the magnitude of this influence. Findings from our simple econometric model are plausible and show that each simulation experiment represents a complex interaction of experimental settings that may not easily be understood by and communicated to non-experts. Meta-analysis proves to be a useful tool for empirically assessing this complexity.Meta-analysis, CGE, Partial Equilibrium, Trade Liberalization, C00, C23, C68, F10, International Relations/Trade,