This document summarizes a method for person re-identification across non-overlapping cameras without person label information in the target domain. It proposes an Adaptive Ranking Support Vector Machines (AdaRSVM) method to address this problem. AdaRSVM relaxes the discriminative constraint to only rely on the positive mean in the target domain without matched image pairs. This domain adaptation approach achieves better re-identification performance than existing methods and can be used for applications like target position estimation, investigations, and traffic management in large camera networks.