But Mr. Wodtke has his work cut out for him. While Samsung's smartphones are dominant throughout the region, the company has been losing market share to Asian handset makers, such as Lenovo Group Ltd., and low-cost local brands largely unheard of outside the region, including Advan Digital, Smartfren, Ninetology and Cherry Mobile. Samsung's challenge in Southeast Asia is an example of a wider problem it faces in other significant markets, including China and India, where local brands are offering increasingly robust devices that rival Samsung's smartphones at a fraction of the price.