## 1 Introduction
In a similar research direction as that followed in this paper, [PERSON] et al. in [23] aim toward a proactive Historian by implementing a predictive control strategy of a water distribution network that is based on Historian gathered data. Although several researches are focusing on this gathered data capitalization toward industrial systems optimization, a fully functional, real-world, tested and validated proactive Historian solution has not been achieved to date. In order to implement a proactive Historian solution, a software reference architecture is primarily needed and, although [24] presents general reference architectures for IIoT and [25] suggests design patterns that should be applied in IIoT, the most suitable software architecture option for a proactive Historian is described in [26]. The architecture proposed by the authors is specifically targeted for a proactive Historian type of application, dividing the required software modules into three distinct layers. The architecture is based on an already-existing classic Historian solution, which is capable of storing chosen working parameters of a technical system and structures the required modules that need to be added in order to transform a classic solution into a proactive solution. The first layer of the proposed architecture is responsible for identifying relations and dependencies between the measured characteristics by using historical stored data and external context data. The identified relations and dependencies, alongside future context data, are used as input for the second layer of the reference architecture, which must be capable of predicting the future evolution of the technical system. The last layer of the reference architecture capitalizes on the results of the previous layer, making use of the future prediction in order to decide how to influence this predicted future evolution so that chosen objectives (such as cost reduction, efficiency improvements, substances consumption reduction, maintenance improvements) are met. Ultimately, the third layer of the reference architecture should be capable of directly influencing the monitored technical system, through actuators, transferring the optimizations to the real-world system. Implementing the entire reference architecture would result in obtaining a closed-loop Historian system, which monitors a technical system, adjusts it for optimization, monitors the system reaction to the adjustment, and so on. Besides presenting the aforementioned reference architecture, the authors also implemented and tested the first level of the architecture in [26], illustrating test cases from the water industry, with reference to a drinking water treatment plant. The current paper picks up the state of the research that was reached in [26] and takes it further down the long path to implement the entire reference architecture and obtain the first proactive Historian application capable of optimizing the monitored system without any human assistance. Achieving the final goal of this research direction demands a considerable research, implementation, and testing effort, which must be divided into several stages. The initial step was taken in [22], where the authors developed a classic Historian solution, but in a lightweight and low-cost implementation, perfectly suited for the industrial requirements. Then, important steps toward the proactive direction were made in [26], where a reference architecture was proposed, the first level of it also being implemented and tested in the water industry. The current paper falls in line with this research, representing the next significant step toward the ultimate goal.