Yahoo Labs has hired 30 Ph.D. level researchers this year and plans to add 20 more by the end of December as CEO Marissa Mayer rebuilds the company's research operations, according to Bloomberg. For the past four years, the lab's budget has been reduced, slowing the pace of research and leading to executive departures. Last year, the group's founder, Prabhakar Raghavan, jumped ship for a position at Google. Mayer told Bloomberg she wants to "build [Yahoo Labs] back up" with more money and more people. In 2012, Yahoo's research budget stood at about $886 million, down 27 percent from 2008. Among the people Yahoo Labs is looking for are research scientists specializing in mobile, personalization and pricing and marketplaces. Yahoo Labs is now run by Chief Scientist Ron Brachman, who previously worked at DARPA, the U.S. agency that was an early Internet pioneer. He also worked on artificial intelligence for AT&T. Among the areas the unit's delving into are multimedia search, traffic shaping -- which melds user recommendations with activities that occur after other community members click -- and Amoeba, an application to uncover trends in online conversations. While Yahoo's streak of acquisitions has been getting the most attention lately, the company's been putting a lot of emphasis on reinvigorating its workforce. Although head count's been reduced in the year since she took over as CEO, during the company's second-quarter earnings call Mayer said attrition dropped 59 percent measured year over year. Also, more tech professionals are expressing interest in working there. Meanwhile, Yahoo's moving its San Francisco office from the financial district to the city's more tech-centric South of Market area. The new home will encompass 70,000 square feet of space in the San Francisco Chronicle building at 901 Mission Street. Over the last year, the company's expanded the San Francisco team to work on Flickr, Yahoo News and a new email service. Currently, it has about 35 jobs posted for the office, including a senior product manager, senior solutions engineers and mobile developers.