Researchers at SunStrength Inc. found a new solar-power technology suitable for cell phones. However, the technology is still being developed and is yet to be proved functional. Activoice Inc. has developed a very useful cell-phone technology based on voice activation. However, the technology is expensive and has yet to prove its full value. Ocean Gale Corp. has developed a technology that can be used with any cell-phone lithium-ion battery to reduce energy consumption. The system has proved to be very effective, but not all cell-phone manufacturers have adopted it yet. Sunstrength Inc.'s new solar-cell technology would be an example of a(n) ________ technology.