Abstract: The Internet of Things (IoT) is a product of the integration of general-purpose computers and embedded systems at an advanced stage, based on microprocessors. The IoT has three sources: intelligence, network, and connectivity. The connectivity source of the IoT is the four channel interfaces of embedded application systems. The IoT comprises numerous interconnected systems, and IoT events are the behavioral processes within these systems. From these numerous IoT events, six behavioral elements can be summarized: storage, sensing, control, communication, management, and interaction. The relationship between the IoT and cloud computing is that of foundation and superstructure: the IoT represents a smart earth, while cloud computing represents smart services.
Keywords: Internet of Things (IoT); IoT systems; IoT events; IoT behavioral elements
The Internet of Things (IoT) and cloud computing are not just hype; they represent the advanced convergence of the internet and embedded systems. The IoT encompasses numerous disciplines and requires a scientific interpretation from multiple perspectives. Embedded systems, a crucial component of IoT technology, have over 20 years of IoT history, and an embedded systems perspective helps in a deep and comprehensive understanding of the essence of the IoT.
1. The Internet of Things from the Perspective of Embedded Systems
Figure 1. The source of the Internet of Things
The Internet of Things (IoT) is a product of the advanced development and integration of general-purpose computers and embedded systems based on microprocessors. It encompasses multiple disciplines and has countless application areas. The IoT has three sources: the source of intelligence, the source of the network, and the source of the connection. The source of intelligence is the microprocessor, the source of the network is the Internet, and the source of the connection is embedded systems. A thorough understanding of these three sources is essential for scientifically defining the connection. Figure 1 illustrates the development history of these three sources of the IoT and their interrelationships.
Both general-purpose computers and embedded systems can be traced back to semiconductor integrated circuits. The advent of the microprocessor provided a standardized intellectual core for human tools. Based on the microprocessor, general-purpose microprocessors and embedded processors formed two major branches of the modern computer knowledge revolution: the independent development eras of general-purpose computers and embedded systems. General-purpose computers have undergone an independent development path from intelligent platforms to the Internet; embedded systems have undergone an independent development path from the Internet of Things (IoT) to localized IoT. The Internet of Things (IoT) is a product of the advanced fusion of the Internet of Things in general-purpose computers and the standalone or localized IoT of embedded systems. In the IoT, the infinite diffusion of microprocessors, in the form of "intelligent cells," endows the IoT with the intellectual characteristics of a "smart earth." Therefore, the IoT must be scientifically defined and interpreted from three sources and a multidisciplinary perspective.
Like embedded systems, the disciplines related to the Internet of Things (IoT) include microelectronics, computer science, electronic technology, and countless other application disciplines. Each discipline will inevitably have a limited perspective when interpreting the IoT. A "blind men and the elephant" approach is needed to understand the IoT—combining different perspectives to approach the truth.
Currently, when searching for a definition of the Internet of Things (IoT), one is reminded of the vague and descriptive definition of embedded systems. The current definition of IoT faces the awkward situation of failing to clearly explain the essence of "connection." The fundamental reason is that after the modern computer knowledge revolution entered an era of independent development between general-purpose computers and embedded systems, embedded systems lacked an independent form. People only saw general-purpose computers, not embedded systems, and were unaware of the IoT history of embedded systems.
2. The Source of the Internet of Things
The origin of the Internet of Things (IoT) is embedded systems. Embedded systems originated from embedded processors and have a history of over 30 years. They experienced the era of microcontrollers, which developed independently in the field of electronic technology, before entering the era of embedded systems supported by multiple disciplines in the 21st century. From its inception, embedded systems have taken "Internet of Things" as their mission, specifically manifested in embedding themselves into physical objects to achieve the intelligentization of those objects. Twenty years ago, in my book "MCS51 Series Microcontroller Application System Design" [1], I proposed the concept of four channel interfaces for microcontroller application systems. This concept is applicable to all embedded application systems and forms the foundation of the Internet of Things. Figure 2 illustrates the origin of the IoT in embedded systems.
Figure 2. IoT foundation of embedded application systems
Embedded application systems, based on embedded processors or microcontrollers, are embedded into physical objects, providing these objects with a complete IoT interface. The forward channel sensor interface is connected to the physical parameters; the backward channel control interface is connected to the physical object; the human-machine interface enables human-object interaction; and the communication interface enables object-to-object interaction.
As shown in Figure 2, embedded application systems can provide various IoT methods. Taking sensor networks as an example, sensors do not have network access capabilities. Only by using embedded processors or embedded application systems to transform traditional sensors into smart sensors can they interconnect through communication interfaces or access the Internet to form local area sensor networks or wide area sensor networks.
After more than 20 years of development, most embedded application systems now possess local area network (LAN) capabilities or internet connectivity. LANs for embedded application systems include RS485 bus networks, CAN bus networks, fieldbus networks, and wireless sensor networks. The connection between embedded application systems, their LANs, and the internet is transforming the internet into the Internet of Things (IoT).
Since the advent of GPS, embedded application systems have enabled the spatiotemporal positioning of physical objects, ensuring that physical objects in the Internet of Things (IoT) have complete physical information. When implementing IoT, it can provide not only the physical parameters and physical state information of physical objects, but also their spatiotemporal positioning information.
3. Internet of Things and Internet of Things Events
The infinity of the material world determines the infinite number of application areas for the Internet of Things (IoT). However, each specific IoT application exists within a specific IoT system. Examples include traffic violation management IoT systems, smart home IoT systems, remote medical assistance IoT systems, and supermarket self-service payment IoT systems. Each independent and autonomous task process within an IoT system can be called an IoT event.
In the existing traffic violation management system, violations are posted online via video surveillance. Drivers can check their violations online and then pay fines at a bank. If the driver's physical information can be connected to the internet via a mobile phone through automotive electronic networks, and the video surveillance system is also connected to the internet, an IoT system for traffic violation management can be formed. In this IoT system, when the video surveillance system detects a violation, it immediately uploads it to the internet and notifies the driver in real time via mobile communication. After the driver confirms the violation, they can immediately complete the online fine payment. This is a specific IoT event within the traffic violation management IoT system.
Numerous IoT events across different IoT systems can be abstracted into three typical behavioral processes: event initiation, information processing, and result output, or simply initiation, processing, and output. A complete IoT event should possess these three behavioral processes.
3.1 Event Incentives for IoT Events
The event incentivization factor is the triggering factor for an IoT event. An IoT event can only be triggered when an incentivizing event occurs within the IoT system. For example, in an IoT system for managing traffic violations, a "violation event" is the incentivizing behavior for an IoT event.
The "incentives" for IoT events can be categorized into active and passive incentives. Active incentives are often predictable, while passive incentives are often unpredictable. In a smart home IoT system, the incentive for a homeowner to remotely monitor home electrical appliances is an active incentive; the incentive for a fire in a smart home is a passive incentive.
The "incentives" for IoT events typically include raw information that sets requirements for subsequent information processing and control output. For example, in a smart home IoT system, a homeowner might remotely monitor a refrigerator to check the condition of the food inside; or remotely control an air conditioner to turn it on or off.
3.2 Information Processing of IoT Events
Information processing for IoT events refers to the process by which an IoT system interprets the raw information of an event after receiving it, and collects, analyzes, processes, and transmits related information along the IoT event path. For example, in a smart home IoT system, if a remote control "incentive" for an air conditioner is received via a mobile phone, the system will interpret the information in the mobile phone event incentive, verify the owner's identity, understand the controlled object and its status requirements, and then collect indoor temperature and humidity data to formulate an operating strategy for the air conditioner.
Along the IoT event path, there are numerous microprocessors, which are distributed throughout the IoT system as general-purpose computers or embedded application systems. Each microprocessor undertakes a corresponding information processing task.
3.3 Output of IoT Events
The output of an IoT event is the IoT system's response to the event's stimulus. The "stimulus" of an IoT event includes the purposeful requirements of the output. Under normal operating conditions, the output will fully satisfy these requirements. For example, in a smart home IoT system, remote air conditioning control must meet the homeowner's control settings; remote refrigerator monitoring must provide the homeowner with accurate information about stored items.
The output of an IoT event is the IoT system's response to the event stimulus. Therefore, the output of IoT event responses has different real-time requirements. In a smart home IoT system, a fire alarm or burglary alarm must trigger an immediate alarm response; when remotely monitoring a refrigerator, the storage status must be promptly communicated; and when remotely controlling an air conditioner, a specific control action can be scheduled to occur at a specific time.
4. Behavioral Elements of IoT Events
The Internet of Things (IoT) comprises numerous IoT systems, and within these systems, numerous IoT events occur. These different IoT events involve various behavioral processes. However, all these different event processes share common behavioral elements: object storage, object sensing, object control, object communication, object management, and object interaction.
4.1 Storage in the Internet of Things (IoT)
The storage element in the Internet of Things (IoT) refers to the storage of knowledge and information related to IoT events within the IoT system. To meet the requirements of IoT system construction and the processes of IoT events, the IoT system must have sufficient storage space to realize electronic information storage, virtual storage in the real world, virtual-physical interactive storage, and digital file storage.
Electronic information storage refers to the storage of personal information and their assets under a real-name online system; virtual storage in the real world refers to the virtual storage of digital systems, such as online banking, shopping systems, traffic management systems, and authentication systems; virtual-real interactive storage refers to digital virtual storage based on a physical authentication environment, such as the digital file virtual storage of integrated circuits, IP cores, and system circuits based on the physical authentication of FPGAs; and digital file storage refers to the storage of images, audio, and video data.
All stored content in the Internet of Things (IoT) is a quantum-based storage system normalized to "0" and "1" digital symbols, independent of any specific material. Therefore, data stored in the IoT can be converted or transmitted across different media.
4.2 Sensing in the Internet of Things (IoT)
The sensing elements in the Internet of Things (IoT) refer to the perceptual behavior of IoT events towards physical objects within an IoT system. The source of this perceptual behavior is the digital acquisition by sensors in embedded application systems. Typically, the perception in IoT events includes the perception of the physical state and physical parameters of physical objects, as well as the perception of the object's temporal and spatial location information. The perception of physical state and physical parameter information usually relies on various types of sensors to convert the physical state and physical parameters into analog voltage signals, which are then converted into digital signals using analog-to-digital conversion technology and input into the forward channel of the embedded application system. The temporal and spatial location information of physical objects relies on the interactive perception between the embedded application system and the GPS system.
4.3 Control of the Internet of Things (IoT)
The control elements of the Internet of Things (IoT) refer to the control behaviors of IoT events on physical objects within an IoT system. The source of these behaviors is the servo control capability of the embedded application system's control interface over the physical objects. Typically, the embedded application system's control interface outputs normalized "0, 1" digital signals, which must be converted into analog control signals acceptable to the physical objects using appropriate digital-to-analog conversion technology.
4.4 Information in the Internet of Things (IoT)
The "physical information element" in the Internet of Things (IoT) refers to the information flow management behavior of IoT events within an IoT system. This information flow management behavior is primarily manifested in the transformation and transmission of normalized digitized "0" and "1" information. It includes the transformation of "0" and "1" digitized information in different media, the encoding and decoding between different operational stages, and various forms of signal transmission, such as wired and wireless transmission, cable and fiber optic transmission, power grid carrier transmission, and GPRS transmission in communication networks.
4.5 Internet of Things (IoT) Management (Property Management)
The property management element of the Internet of Things (IoT) refers to the management and scheduling of IoT events and behaviors within the IoT system. This management and scheduling includes data flow management, database interconnection, data collection, authentication, licensing systems for information flow, security management, and operational management.
4.6 Internet of Things Interaction (IoT)
The "interactive elements" of the Internet of Things (IoT) refer to the interactive behaviors of stakeholders in an IoT system. Embedded application systems typically have four IoT interfaces: sensing interface, control interface, human-machine interface (HMI), and communication interface. Each interface corresponds to a physical object, such as sensors in the sensing interface, physical objects in the control interface, people in the HMI, and other embedded application systems or their local area networks (LANs) and wide area networks (WANs) in the communication interface. These multiple physical objects and interfaces create diverse interactive behaviors between people, things, and networks (WAN/LAN).
Conclusion
① The Internet of Things era is a new era in which the two major branches of general-purpose microprocessors and embedded processors have moved from separation to integration, that is, a transformative era in which microprocessors have gone from being divided into two to being integrated into one.
② The Internet of Things (IoT) is an intelligent network system that is closely connected to physical objects and enables human-object interaction, human-object-human interaction, and is not limited by time and space.
③ The source of intelligence in the Internet of Things (IoT) is the semiconductor microprocessor, the source of IoT itself is embedded application systems, and the source of the network is the Internet. Each plays a specific role in the IoT.
④ The Internet of Things (IoT) is a product of multiple disciplines, and any single discipline's explanation of it will have limitations. A comprehensive and scientific explanation of the IoT, integrating perspectives from various disciplines, is of great significance to the healthy development of my country's IoT industry.
⑤ The Internet of Things (IoT) is closely related to cloud computing:
The Internet of Things (IoT) and cloud computing are related as foundation and superstructure; IoT is the smart earth, and cloud computing is smart services; IoT is the foundation of IoT, and cloud computing is software services; cloud computing is a comprehensive, unlimited global service system in the IoT era.
References
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[4] He Limin. Cross-disciplinary integration of pillar disciplines in embedded systems [J]. Microcontrollers & Embedded Systems Applications, 2008(5).
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