* Anteon International, a Fairfax high-technology government contractor, won a 16-month, $45 million contract from the Naval Sea Systems Command to provide technical and management support to the Aegis missile defense program. Anteon will provide strategic planning for technology programs; concept development and requirement analysis; system design; engineering and integration; test evaluation; and acquisition and life-cycle management.

* Essex, a Columbia defense contractor, completed its acquisition of Performance Group, a Fredericksburg company that specializes in geographic information systems, imagery processing and analysis, spatial data development, environmental consulting, visualization and information technology. Performance Group is privately owned with 39 full-time employees and $4.5 million in revenue in 2003. It is the second acquisition in 2004 for Essex, which bought Computer Science Innovations in April.

* Guilford Pharmaceuticals of Baltimore named William F. Spengler executive vice president and chief financial officer effective July 15. Spengler most recently served as president, chief operating officer and director of Osteoimplant Technology.

* SafeNet, a Baltimore information security company, named Carole Argo president and chief operating officer and Ken Mueller chief financial officer. Argo had been SafeNet's senior vice president and chief financial officer since 1999. Before joining SafeNet, she was chief financial officer of Optelecom. Mueller most recently was chief financial officer for Microsoft Business Solutions.

Compiled from reports by Washington Post staff writers, PR Newswire and Business Wire.