Some Examples of the Use of Simulation in U.S. and Canadian Agriculture

Mathematical simulation is a technique widely used by agricultural engineers to determine systems interactions, to evaluate technical feasibility, to determine economic feasibility, to design complex structures and to help with managing production. In the past, simulation has been used one level removed from the farmers who manage operation on a day-to-day basis. This is changing.Three completely different types of simulations are presented: (1) a static and deterministic simulation of on-farm ethanol production that models the conversion process and determines economic feasibility; (2) a dynamic and deterministic simulation of maize production, including harvest and drying that is weather dependent; (3) a static and stochastic simulation that uses Monte Carlo techniques to obtain information about strength and performance of glued-laminated beams.We believe that inexpensive computing capability will tremendously increase the use of simulation models, such as the three described, that will help farmers better manage their production systems.     

3-edge-connected embeddings have few singular edges

We show that a 3-edge-connected graph embedded in a surface of Euler characteristic χ has at most 3 – 3χ singular edges, except in the projective plane, where it has at most one singular edge, and the sphere, where it has none. This bound is best possible for all surfaces.     

Die Nichtexistenz transitiver Erweiterungen gewisser Permutationsgruppen

Ohne Zusammenfassung