en-based tablet computer, and a wearable computer with flat-panel display. "Results indicated that tablet and wearable computers may significantly reduce rework, while productivity decreased slightly when tablet and wear- able computers were used," Elvin says. With paper documents, for example, 4.15 percent of total project time was spent redoing some aspect of the project, compared with 1.38 percent with the wearable computer. Elvin says commu- nications that use paper were probably less efficient because the quality of paper documents faxed to job sites is often poor; electronic tablets or wear- able computers, however, allow construction-team members to enlarge parts of documents to view greater detail. Elvin says a dip of less than 8 percent in productivity indicated in the study "is typical of the initial decline in productivity observed when a new technol- ogy is introduced to a workforce in any field." Further study is needed to deter- mine the long-term productivity impacts of tablet and wearable computers once the user had become proficient in their use." 2.4 SMART FABRICS A mobile phone with lapels? An MP3 player with a zipper? In the world of "smart fabrics," clothing and electronics can be indistinguishable. Werner Weber, senior director of corporate research at Infineon Technologies, a Munich-based semiconductor design firm, believes that many of the gadgets people currently take for granted-including phones, home entertainment devices, health monitors, and security systems-will literally be woven into the fabrics they wear, walk over, and sit on. The Munich-based chipmaker re- cently developed a carpet that can detect the presence of people-guests or intruders-and then automatically activate a security system or light the way to an exit in the event of a fire or other emergency. The carpet is woven with conductive fibers with pressure, temperature, and vibration sensor chips, as well as LEDs, embedded into the fabric. "The goal is to present security services and guiding functions in buildings, such