Understanding cover crop and tillage system interactions within specific environments can help maximize productivity and economic returns of cotton (Gossypium hirsutum L.) produced on sandy coastal plain soils of the southeastern USA. A strip-plot design with three replications was used to evaluate the cover crops Austrian winter pea [Pisum sativum L. ssp. arvense (L.)], balansa clover (Trifolium michelianum Savi), crimson clover (Trifolium incarnatum L.), hairy vetch (Vicia villosa Roth subsp. villosa), oil seed radish (Raphanus sativus L.), black oat (Avena strigosa Schreb.), and rye (Secale cereale L.) and tillage (strip and none) influences on cotton grown on a Bonifay fine sand (loamy, siliceous, subactive, thermic Grossarenic Plinthic Paleudults) near Waynesboro, GA from 1999 to 2003. Drought influenced production 3 of 4 yr. Cover crop biomass was greatest from rye, intermediate from black oat, oilseed radish, hairy vetch, and Austrian winter pea. Hairy vetch and Austrian winter pea contained more than 80 kg N ha 21 while other cover crops averaged ,40 kg N ha 21 . Cotton yields following black oat and rye had returns above variable costs ha 21 $461 and $406, respectively. Strip-tillage increased yields by 192 kg ha 21 and annual returns by $112 ha 21 over no-tillage, most likely due to improved available water. Combining strip-tillage with black oat was the best combination for maximizing profit. Using black oat with strip-tillage could increase cotton profit by $50 to $75 ha 21 compared to systems using rye on the 1.45 million ha of cotton where conservation systems have been adopted.

Programming-by-demonstration (PBD) can be used to create tools and methods that eliminate the need to learn difficult computer languages. Gamut is a PBD tool that nonprogrammers can use to create a broader range of interactive software, including games, simulations, and educational software, than they can with other PBD tools. To do this, Gamut provides advanced interaction techniques that make it easier for a developer to express all aspects of an application. These techniques include a simplified way to demonstrate new examples, called "nudges," and a way to highlight objects to show they are important. Also, Gamut includes new objects and metaphors like the deck-of-cards metaphor for demonstrating collections of objects and randomness, guide objects for demonstrating relationships that the system would find too difficult to guess, and temporal ghosts which simplify showing relationships with the recent past. These techniques were tested in a formal setting with nonprogrammers to evaluate their effectiveness.

By combining the strengths of multiple interaction techniques and inferencing algorithms, Gamut can infer behaviors from examples that previously required a developer to annotate or otherwise modify code by hand. Gamut is a programming-by-demonstration (PBD) tool for building whole applications. It revises code automatically when new examples are demonstrated using a recursive procedure that efficiently scans for the differences between a new example and the original behavior. Differences that cannot be resolved by generating a suitable description are handled by another AI algorithm, decision tree learning, providing a significantly greater ability to infer complex relationships. Gamut's interaction techniques facilitate demonstrating many examples quickly and allow the user to give the system hints that show relationships that would be too time consuming to discover by search alone. Altogether, the concepts combined in Gamut will allow nonprogrammers to build software they never could before.

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The Garnet User Interface Development Environment contains a comprehensive set of tools that make it significantly easier to design and implement highly-interactive, graphical, direct manipulation user interfaces. The toolkit layer of Garnet provides a prototype-instance object system, automatic constraint maintenance, an efficient retainedobject graphics output model, a novel input model, two complete widget sets, and complete debugging tools. Garnet also contains a set of interactive user interface editors that aim to make it possible to create the user interface without programming.Instead, the user draws examples of the desired graphics and demonstrates their behaviors. The associated video provides an overview of the entire Garnet system.

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Marquise is a new interactive tool that allows virtually all of the user interfaces of graphical editors to be created by demonstration without programming.A "graphicẽ ditor" allows the user to create and manipulate graphical objects with a mouse. This is a very large class of programs and includes drawing programs like MacDraw, graph layout editors like MacProject, visual language editors, and marty CAD/CAM programs, The primary innovation in Marquise is to allow the designer to demonstrate the overall behavior of the interface.To implement this, the Marquise framework contains knowledge about palettes for creating and specifying properties of objects, and about operations such as selecting, moving, and deleting objects. The interactive tool uses the framework to allow the designer to demonstrate most of the end user's actions without programming, which means that Marquise can be used by non-programmers.

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