David Emma has been named vice president, OEM and licensing, at Color Kinetics Inc., a Boston-based designer of solid-state lighting systems and technologies. Emma most recently was vice president of the Communications Modules Division of Integrated Circuits Systems, a maker of silicon timing devices for the communications equipment, consumer and business electronics industries. Before that, he was vice president of sales and marketing at Micro Networks, a provider of radio frequency and microwave components and subsystems for the communication, networking and wireless industries, and vice president of marketing for CP Clare Corp., now a division of IXYS Corp.    . . .    Andrew Humphris was appointed CTO at Infinitesima, a Bristol, England, developer of scanning probe microscopy technology. Humphris was a founder of the company, a spinoff from the University of Bristol Physics Department, where he formerly lectured. His research in nanoscience has led to the development of Infinitesima's core technologies, including VideoAFM a video-rate atomic force microscope.    . . .    Kenneth C. Frederick was appointed CEO of Molecular Imaging Corp., a San Diego provider of positron emission tomography imaging services. Frederick has served on the company's board since June.    . . .    David K. McQuiggan was named senior vice president of Three-Five Systems Inc.'s platform display business. McQuiggan was formerly CEO and a board member at Densitron Technologies PLC, a UK maker of embedded computing products and information display systems; he was previously a director at Vbest Electronics Ltd., a Taiwanese manufacturer of color and monochrome LCD panels and modules.