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We integrate structured data and text using the unchanged, standard relational model. We started with the premise that a relational system could be used to implement an information retrieval (IR) system. After implementing a prototype to verify that premise, we then began to investigate the performance of a parallel relational database system for this application. We also tested the effect of query reduction on accuracy and found that queries can be reduced prior to their implementation without incurring a significant loss in precision/recall. This reduction also serves to improve run‐time performance. After comparing our results to a special purpose IR system, we conclude that the relational model offers scalable performance and includes the ability to integrate structured data and text in a portable fashion. © 1997 John Wiley & Sons, Inc.

Background: Energy input in agriculture has increased tremendously and accounts for about 17% of total energy consumed in the USA. Precision agriculture involves knowledge-based technical management systems to optimize application of fertilizer, chemicals, seeds, and irrigation resources to reduce input costs and to enhance crop yield while simultaneously reducing harmful environmental impacts associated with inefficient use of agricultural inputs. It also uses GPS-based auto-guidance systems in agricultural vehicles to reduce overlapping of equipment and tractor passes, thus saving fuel, labor, time, and soil compaction with environmental benefit.

Abstract-Data from an optical imaging sensor and a small-footprint lidar were used to examine the relation between canopy reflectance and outer surface complexity in forest stands in the southern Cascades of Washington state. Albedo was estimated from the Airborne Visible Infrared/Imaging Spectrometer; canopy surface variation (termed "rugosity") was estimated from small-footprint lidar; and stand ages were obtained through U.S. Forest Service records and global information system coverages. Results showed that albedo from Douglas-fir/western hemlock stands decreased, and variation in the outer surface of the canopy increased with age. Estimates of rugosity increased most rapidly in young stands and then more slowly after about 150 years. Albedo declined by 10% across the age sequence, suggesting that older stands of this forest type enjoy a substantial advantage in energy input. The results highlight the impacts of land-cover change on local energy balance and climate.