ABSTRACT
The way most people view a computer is as a device used to perform simulations, prepare presentations, edit documents, and even play video games, hence in the form of a desktop or notebook. Nevertheless, most computers go unperceived, working in the background of our daily lives, including in vehicles, house appliances, office equipment, manufacturing, and even the ubiquitous cell phone. These less perceived computers are known as embedded systems, and in lame terms, it is a computer that is designed specifically with one (or few) purpose to reduce processing time, costs, and/or size. Today, embedded systems are no longer restraint by processing power, the capability to maintain strict task deadlines, high costs, or size. Since most embedded systems are connected
to the local network and can communicate with other embedded systems, these have evolved to what is known today as cyber-physical systems or CPS [1]. These are systems that still interact with the physical world and perform specific tasks, as embedded systems do, but are much more versatile and powerful in terms of processing capabilities. Cyber-physical systems are able to communicate within an intranet, but are not necessarily connected to the Internet. On the other hand, we have the Internet of Things (IoT), in which we have embedded systems connected to the Internet periodically feeding it with data. A server or receiving device somewhere in the Internet, commonly referred to as the cloud, turns these data into information, knowledge, or optimistically wisdom, terminology used in the context of information science, more specifically, the data, information, knowledge, and wisdom (DIKW) pyramid. The IoT, in contrast to cyber-physical systems, can also interact with data, which even though is stored in a physical media is not considered interacting with the physical world. Also, the IoT attempts to climb the DIKW pyramid as much as possible to use the data acquired in the most useful way possible, while cyber-physical systems are meant to mainly control a specific aspect in the physical domain, and to achieve this, the quickest route is the optimal (hence keeping the system simple, reducing the amount of DIKW layers climbed). There may be more ways to explain these terms and their differences; if these are not clear, we encourage the reader to pursue further readings into these interesting topics. Some good sources to start from are the books [1,2] and the website [3]. When the IoT is combined with cyber-physical systems, the resulting system is an interlaced mesh of subsystems that interact not only in the virtual domain but also in the physical domain. The control decisions performed in one discipline can potentially affect (positively or negatively) the decisions of other disciplines; therefore, the affected discipline takes control over a certain action that itself might affect another discipline creating a single entity that is constantly optimizing resources while maintaining balance. We call this system the Internet of interlaced cyber-physical things (IoICPT). Figure 14.1 attempts to portray this concept. In this system, the cyber-physical subsystems interact not only through the communication links but also through the physical world. A simple example could be an unmanned system that is manufacturing a particular product and, in real-time, it is been informed that the demand of this product is increasing; hence, the system enters an overdrive mode. This decision caused the system to generate more pollution, so another cyber-physical subsystem which is attempting to filter the air informs all devices, which are generating air pollutants, to decrease their use when possible. The system may also: alert hospitals that more polysomnograms will be required and to prepare the rooms necessary for the estimated amount of patients admitted, and so forth. The possibilities are endless. Basically, this system would be the brain of a smart city and just like the Internet does not reside in any particular place nor does the brain of a smart city; rather, it is spread throughout the city. To portray the interlacing of various applications in the different disciplines, we have chosen six fields: e-health, energy, transportation, building/home, mobile networks, and environment. The interleaved system is shown in Figure 14.2.
