Adaptive Agent Modeling as a Tool for Trade and Development Theory

This paper makes use of an adaptive agent framework to extend traditional models of comparative advantage in international trade, illustrating several cases which make theoretical room for industrial policy and the regulation of trade. Using an agent based implementation of the Hecksher-Ohlin trade model, the paper confirms Samuelson’s 2004 result demonstrating that the principle of comparative advantage does not ensure that technological progress in one country benefits its trading partners. It goes on to demonstrate that the presence of increasing returns leads to a situation with multiple equilibra, where free market trading policies can not be relied on to deliver an outcome which is efficient or equitable, with first movers in development enjoying permanent advantage over later developing nations. Finally, the paper examines the impact of relaxation of the Ricardian assumption of capital immobility on the principle of comparative advantage. It finds that the dynamics of factor trade are radically different from the dynamics of trade in goods and that factor mobility converts a regime of comparative advantage into a regime of absolute advantage, thus obviating the reassuring equity results which stem from comparative advantage.Agent-based modeling; comparative advantage; increasing returns; international trade

Adaptive Agent Modeling in a Policy Context

This dissertation examines the utility of adaptive agent modeling (also referred to as agent-based modeling or individual based modeling) as a tool in public policy research. It uses the adaptive agent technique to produce useful results in three diverse areas. It demonstrates that the adaptive agent framework can be used to extend traditional models of comparative advantage in international trade, showing that the presence of increasing returns to scale in some industries shifts the basis of comparative advantage arguments, making room for industrial policy and the regulation of trade. Next, the dissertation demonstrates that the size distribution of cities within nations, generally thought to approximate the "Zipf" distribution, can be reproduced using a simple agent-based model. This model produces insights into the evolution of the distribution as well as departures from it especially in France and Russia. This understanding of urban dynamics has implications for easing the structural transition of the Russian economy and for designing policies to reduce the size of megacities in the developing world. The dissertation goes on to examine individual level data from the Guatemalan civil war from an adaptive agent modeling perspective. It finds several novel patterns in the data which may serve as benchmarks for adaptive agent modeling efforts and suggests avenues by which existing conflict models might be brought into closer accord with the data. The dissertation concludes that adaptive agent modeling is useful in a policy context because it allows quantitative work to be done while relaxing some of the unrealistic assumptions which are often required to gain analytical traction using traditional methods. The method is found to be particularly useful in situations where path dependence, heterogeneity of actors, bounded rationality, and imperfect information are significant features of the system under examination. The individual based nature of the method is also found to be well suited to assessing distributional impacts of changes in process or policy

Hanbury Brown and Twiss interferometry at a free-electron laser

We present measurements of second- and higher-order intensity correlation functions (so-called Hanbury Brown and Twiss experiment) performed at the free-electron laser (FEL) FLASH in the non-linear regime of its operation. We demonstrate the high transverse coherence properties of the FEL beam with a degree of transverse coherence of about 80% and degeneracy parameter of the order 10^9 that makes it similar to laser sources. Intensity correlation measurements in spatial and frequency domain gave an estimate of the FEL average pulse duration of 50 fs. Our measurements of the higher-order correlation functions indicate that FEL radiation obeys Gaussian statistics, which is characteristic to chaotic sources.Comment: 19 pages, 6 figures, 1 table, 40 reference

Uniform plant stands promote pod set and boost seed yield in canola

Non-Peer Reviewe

Revealing three-dimensional structure of individual colloidal crystal grain by coherent x-ray diffractive imaging

We present results of a coherent x-ray diffractive imaging experiment performed on a single colloidal crystal grain. The full three-dimensional (3D) reciprocal space map measured by an azimuthal rotational scan contained several orders of Bragg reflections together with the coherent interference signal between them. Applying the iterative phase retrieval approach, the 3D structure of the crystal grain was reconstructed and positions of individual colloidal particles were resolved. As a result, an exact stacking sequence of hexagonal close-packed layers including planar and linear defects were identified.Comment: 8 pages, 5 figure

Update on fall dormant seeded canola research

Non-Peer Reviewe