This synthesis of the research on direct manipulation interfaces explores the nature of directness in computer interfaces and demonstrates that the concept of directness is complex, including two gulfs--for execution and evaluation--and two kinds of mappings--semantic mappings and referential distance. Examination of the complexities of the…

The course is designed to train noise survey technicians during a 3-5 day period to make reliable measurements of 75 percent of the noise problems encountered in the community. The more complex noise problems remaining will continue to be handled by experienced specialists. These technicians will be trained to assist State and local governments in…