Cyber-physical systems: Milestones and research challenges

In the past decade, we have witnessed an unparalleled success of information and communication technologies (ICT), which is expected to be even more proliferating and ubiquitous in the future. Among many ICT applications, ICT components embedded into various devices and systems have become a critical one. In fact, embedded systems with communication capability span virtually every aspect of our daily life. An embedded system is defined as a computer system designed to perform dedicated specific functions, usually under real-time computing constraints. It is called ‘‘embedded’’ because it is embedded as a part of a complete device or system. By contrast, a general-purpose computer is designed to satisfy a wide range of user requirements. Embedded systems range from portable devices such as smart phones and MP3 players, to large installations like plant control systems. Recently, the convergence of cyber and physical spaces [1] has further transformed traditional embedded systems into cyberphysical systems (CPS), which are characterized by tight integration and coordination between computation and physical processes by means of networking. In CPS, various embedded devices with computational components are networked to monitor, sense, and actuate physical elements in the real world. Examples of CPS encompass a wide range of large-scale engineered systems such as avionics, healthcare, transportation, automation, and smart grid systems. In addition, the recent proliferation of smart phones and mobile Internet devices equipped with multiple sensors can be leveraged to enable mobile cyber-physical applications. In all of these systems, it is of critical importance to properly resolve the complex interactions between various computational and physical elements. In this guest editorial, we first provide an overview of CPS by introducing major issues in CPS as well as recent research efforts and future opportunities for CPS. Then, we summarize the papers in the special section by clearly describing their main contributions on CPS research. The remainder of the editorial is organized as follows: In Section 2, we provide an overview of CPS. We first explain the key characteristics of CPS compared to the traditional embedded systems. Then, we introduce the recent trend in CPS research with an emphasis on major research topics in CPS. We introduce recent CPS-related projects in Section 3. Summary of the papers in the special section follows in Section 4 by focusing on their contributions on CPS research. Finally, our conclusion follows in Section 5.