Purdue's School of Industrial Engineering continues to offer one of the nation's preeminent PhD programs, providing research concentrations in human factors, manufacturing, operations research, and production systems. PhD students are encouraged to participate in multi-disciplinary studies and multi-cultural educational efforts in one or more of our diverse research areas, including: Aviation Human Factors, Digital Human Modeling, Distributed Control, Energy Systems, Ergonomics, E-work, E-business, E-service Systems , Financial Engineering, Global Systems, Group Work and Communications, Health Care Engineering, Human-Robot Interaction, Intelligent Systems, Information Visualization, Machining Processes, Materials Processing, Nano-Manufacturing, Nonlinear Optimization, Safety Engineering, Service Engineering and Simulation Optimization.