Azoheteroarenes are relatively new photoswitchable compounds, where one of the phenyl rings of an azobenzene molecule is replaced by a heteroaromatic five-membered ring. Recent findings on methylated azoheteroarenes show that these photoswitches have potential in various optically addressable applications. The thermal stability of molecular switches is one of the primary factors considered in the design process. For molecular memory or energy storage devices, long thermal relaxation times are required. However, inducing a short thermal isomerization lifetime is required to release stored energy or as an alternative to photoswitching to avoid overlapping absorption spectra that reduce switching fidelity. In this study, we investigate how oriented external electric fields can be used to tune the thermal isomerization properties of three unsubstituted heteroaryl azo compounds-azoimidazole, azopyrazole, and azopyrrole. We show that favorable electric field orientations can increase the thermal half-life of studied molecules by as much as 60 times or reduce it from tens of days to seconds, compared to their half-life values in the field-free environment. A deeper understanding of the relationship between structure and kinetic properties provides insight as to how molecular switches can be designed for their electric field response in switching applications.

Engineering distributed control systems is a complex task, where the complexity and, thus, costs of the software development are growing rapidly. To keep the software complexity at an acceptable level and save time for development and subsequent maintenance, new solutions are sorely needed. In this paper, we investigate the advantages of using skills - universal control device interfaces - for generating complex logic in distributed control environments. By enriching a skill interface with the information about the dynamic behavior of a component under control, we compose the functionalities of individual control devices. The logic, required for such composition, is automatically derived from the interface description and the production plan, identifying the required skill sequence. The evaluation, executed using two industrial demonstrators, shows that the approach successfully handles different behavioral models and is capable of generating fault-tolerant orchestrators, including error handling scenarios. Overall, for developing a complex logic in a distributed skill-based automation system, the proposed approach shows significant savings in development time allowing to automate the skill composition task.

The fourth industrial revolution (Industry 4.0) anticipates unplanned changes of production processes. Production changes may trigger synthesis, and preferably optimization, of architecture-level decisions, such as service deployment and composition. Performing such architecture-level decisions manually is difficult due to the ever-rising complexity of Industry 4.0 systems. In order to (semi-)automate the architecture synthesis and optimization, we propose an approach of service deployment and composition by using existing domain models. Our contribution is threefold: (1) We suggest a workflow with domain models for architecture synthesis in the industrial automation. (2) We display the formalization on a part of the workflow and provide an initial prototype of service deployment synthesis using a satisfiability modulo theories (SMT) solver. (3) We envision a way of service composition and code generation, and prototypically implemented it as conclusion of the suggested workflow. We demonstrate the practical use of the proposed approach in the Industry 4.0 scenario, i.e., flexible production of new products.

An asset administration shell (AAS), as a key concept of Industry 4.0 (I4.0), provides a machine-accessible interface to any kind of asset. To enable interoperability and smooth integration of the devices into the I4.0 middleware, an application implementing the device's functionality should be able to interact with different AASs. In this work, we investigate the integration of the Programmable Logic Controller (PLC) runtime systems into the I4.0 middleware. For doing this, we specify the function blocks (FBs) for connecting the PLCs with AASs and other I4.0 components, such as registry and discovery server. We analyze the requirements of such FBs while focusing on REST/HTTP- and OPC UA-based AASs, and provide interface specification for IEC 61499- and IEC 61131-3-based FBs. Furthermore, we implemented an FB library that enables communication with an AAS from the respective control applications. Those FBs allow accessing properties and invoking operations of remote AASs, as well as hosting AASs submodels. Common functionalities, such as registering the runtime system at the registry component, or finding AASs, are also supported. The results obtained in this paper will ease interaction with the complex AAS structure from the low-level devices.

Industrial systems have traditionally been kept isolated from external networks. However, business benefits are pushing for a convergence between the industrial systems and new information technology environments such as cloud computing, as well as higher level of connectivity between different systems. This makes cybersecurity a growing concern for industrial systems. In strengthening security, access control is a fundamental mechanisms for providing security in these systems. However, access control is relatively immature in traditional industrial systems, as compared to modern IT systems, and organizations' adherence to an established cybersecurity standard or guideline can be a deciding factor for choices of access control techniques used. This paper presents the results of a questionnaire study on the usage of access control within industrial system that are being developed, serviced or operated by Swedish organizations, contrasted to their usage of cybersecurity standards and guidelines. To be precise, the article focuses on two fundamental requirements of cybersecurity: identification and authentication control, and presents related findings based on a survey of the Swedish industry. The goal of the study is breaching the gap between the current state and the requirements of emerging systems with regards to access control.

Heavy metals are naturally occurring elements, but they are regarded as significant environmental pollutants due to their high density and high toxicity even at low concentrations. The aim of this paper is the evaluation of the pollution level of heavy metals in the river and riverbank sediments, as well as the estimation of their origin and spatial differences along the course of the Vrbas River through Banja Luka. The concentrations of metals have been assessed using the Inductively coupled plasma ? optical emission spectrometry and Advanced mercury analyzer for mercury determination. The anthropogenic impact on heavy metal concentration in sediments was estimated by the calculating of pollution indices: geoaccumulation index (Igeo), contamination factor (Cf), pollution load index (PLI) and potential ecological risk index (Er). Obtained results indicate that there is no statistically significant spatial difference in metal concentration, indicating that heavy metals in sediments have a constant source. The anthropogenic impact expressed by the values of pollution indices showed that sites are generally uncontaminated by Co, Cr and V and moderately contaminated by Zn, Cu and Ni. On the contrary, lead, mercury and cadmium pose the highest ecological risk. The anthropogenic source of Pb, Hg and Cd is industry, municipal waste and the combustion of fossil fuels. The obtained results demonstrate the high ecological risk and the need for environ-mental monitoring, with the aim to support an efficient strategy to reduce local pollution and contamination of the investigated system.

DevOps represent the tight connection between development and operations. To address challenges that arise on the borderline between development and operations, we conducted a study in collaboration with a Swedish company responsible for ticket management and sales in public transportation. The aim of our study was to explore and describe the existing DevOps environment, as well as to identify how the feedback from operations can be improved, specifically with respect to the alerts sent from system operations. Our study complies with the basic principles of the design science paradigm, such as understanding and improving design solutions in the specific areas of practice. Our diagnosis, based on qualitative data collected through interviews and observations, shows that alert flooding is a challenge in the feedback loop, i.e. too much signals from operations create noise in the feedback loop. Therefore, we design a solution to improve the alert management by optimizing when to raise alerts and accordingly introducing a new element in the feedback loop, a smart filter. Moreover, we implemented a prototype of the proposed solution design and showed that a tighter relation between operations and development can be achieved, using a hybrid method which combines rule-based and unsupervised machine learning for operations data analysis.