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Singing Alarms Could Save
the Blind{{/B}} If you cannot see, you may not be able to find your way out of a burning building - and that could be fatal. A company in Leeds could {{U}}(51) {{/U}} all that with directional (定向的) sound alarms capable of guiding you to the exit. Sound Alert, a company run {{U}}(52) {{/U}} the University of Leeds, is installing the alarms in a residential home for {{U}}(53) {{/U}} people in Sommerset and a resource centre for the blind in Cumbria. The alarms produce a {{U}}(54) {{/U}} range of frequencies that enable the brain to {{U}}(55) {{/U}} where the sound is coming from. Deborah Withington of Sound Alert says that the alarms use most of the frequencies that can be {{U}}(56) {{/U}} by humans. "It is a burst of white noise that people say sounds like static (静电噪音) on the radio," she says. "its life-saving potential is {{U}}(57) {{/U}}." She conducted an experiment in which people were filmed by thermal-imaging (热效应成像) cameras trying to find their {{U}}(58) {{/U}} out of a large smoke-filled room. It {{U}}(59) {{/U}} them nearly four minutes to find the door without a sound alarm, {{U}}(60) {{/U}} only 15 seconds with one. Withington studies how the brain {{U}}(61) {{/U}} sounds at the university. She says that the {{U}}(62) {{/U}} of a wide band of frequencies can be pinpointed (精确地确定) more easily than the source of a narrow band. Alarms {{U}}(63) {{/U}} on the same concept have already been installed on emergency vehicles. The alarms will also include rising or falling frequencies to {{U}}(64) {{/U}} whether people should go up or down stairs. They were {{U}}(65) {{/U}} with the aid of a large grant from British Nuclear Fuels. |