## 3 Systemic Uncertainty vs. Internet of Things  
An IoT sensor network is a specific combination of technology, management, and application domains (Figure 1), specifically designed to satisfy the desires of the observer (and the social system, represented by the observer) regarding both the phenomenon and the way it is to be measured.  
Figure 1: The main important elements of IoT sensor networks. Source: [4].  
[PERSON] in 1981 made an in-depth analysis of uncertainty regarding complex systems. Despite the huge technological gap between the systems of 40 years ago (which were not even based on Internet networks) and the current complex IoT systems, the validity and importance of the following aspects of system uncertainty should be emphasized [17]: (a) the great number of elements in the system, their high heterogeneity and variability over time, (b) the very large number of possible states, functions of the system and its individual elements, (c) the difficulty of recognizing the states and relationships of the subsystems interdependent with the analyzed system, (d) the impossibility of effective management of the complete system resulting from limited possibilities of evaluating the significance of various states of the system and possible errors in the retrieval, transmission, processing, and aggregation of information generated in the system, (e) the lack of practical possibility of full representation of the system in the form of a model, and (f) the impossibility of determining the full future state of the system resulting from, among other things, the huge number of possible combinations of information generated by the system components.  
In relation to the research of [PERSON]. [PERSON] and [PERSON] [5], in the case of IoT networks the problem is not the lack of information. The problem is the uncertainty of uniform structure, compatibility of information from different sources (sensors come from different manufacturers), and the danger of false information. In addition, in the case of large complex networks, such as the IoT, it is necessary to remember the potential uncertainty resulting from the excess of information, not its deficiency.  
In the context of IoT sensor networks, uncertainty arises in the measurement of epistemological situations, where the probability distribution of the discrepancy between the true (expected) value and the measured value is not known, or where utility is not assignable. Some aspects of such uncertainty may be attributable to the structure of the instrument, while others may be attributable to the observer and the observer system, where the sources of uncertainty may be multiple. In both cases, uncertainty may arise from [4; 18; 19]:  
* Different perceptions, understanding, and modification of uncertainty by different participants in such a system,
* Different origins and quality of sensors, measurements, and instruments,
* Flaws in IoT implementation caused by lack of device compatibility,
* Violation of the privacy of users,
* Security issues--e.g., IoT sensors are connected in event/phenomenon management systems, aiming to show the status of the system. However, it is often very difficult to interpret and distinguish which phenomena are legitimate and which are based on malicious events.