Effects of rotation length, crop sequence, and fertilization on yields and quality of spring wheat (Triticum aesti;um L.) were examined for eight crop rotations over a 27-yr period
A combine harvester econometric simulation model was developed with the goal of matching the combine forward speed to the maximum harvested net income per acre. The model considers the machinery management costs of owning a combine and platform header for harvesting wheat. A statistical Design of Experiment (DOE) was used to evaluate the model using tri-level variables; the medium values constituted the model base case. Of the 27 input variables, the optimum speed was significantly influenced by the crop area, G/MOG ratio, grain unit price, field yield, field efficiency, grain moisture content, probability of a working day in the post-optimum period, estimated harvesting day length, and the timeliness importance factor. The developed optimum speed prediction equation estimated the full model well (R2 = 0.94). Five inputs significantly influenced both the optimum speed and the harvested net income: G/MOG, grain price, field yield, estimated harvesting day length, and the timeliness factor. It is expected that the developed econometric model will be useful for determining the real-time economic performance of a combine harvester.
This paper reports on the experience of the authors in attempting to support data base transactions on top of an existing operating system transaction manager. It will be seen that significant modifications to both the example data base system and the example operating system are required to support the concept. The conclusion to be drawn is that operating system transaction managers will have to be designed more generally than is now suggested and that application programs (such as data base systems) will have to participate in the transaction management process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.