South Korea will seek to develop a new, open-source operating system (OS) for mobile phones that will help secure local smartphone makers\' future competitiveness against their global rivals such as Apple Inc., a government official said Monday. The move comes shortly after Google Inc. announced its purchase of Motorola Mobility, a hardware company that makes phones based on Google\'s Android operating system. The purchase is expected to herald a new competitor that could compete effectively with Apple, which makes iPhones based on its own operating system. But the deal also poses challenges to South Korean companies such as Samsung Electronics Co., which makes Android-running smartphones.