Teodora Sanislav

About dependability in cyber-physical systems

This paper presents definitions characterizing the concepts regarding cyber-physical systems and dependability. Cyber-physical systems incorporate computing, communication and storage capabilities with monitoring and/or control of entities in the physical world in a dependably, securely, efficiently and real-time way. The challenges of cyber-physical system research are concerning: real-time system abstractions; robustness, safety and security; QoS composition; and nor least dependability. Dependability is first introduced as a global concept that subsumes the usual attributes of reliability, availability, safety, integrity and maintainability. The paper aims to define research challenges to achieve the dependability in cyber-physical hydropower systems. The significant challenge of the dependability in cyber-physical hydropower systems is evaluation of the system behavior in terms of interdependencies between cyber and physical components of the system.

A Cyber-Physical System for Environmental Monitoring

This paper presents the development of a cyber-physical system that monitors the environmental conditions or the ambient conditions in indoor spaces at remote locations. The communication between the systems components is performed using the existent wireless infrastructure based on the IEEE 802.11 b/g standards. The resulted solution provides the possibility of logging measurements from locations all over the world and of visualizing and analyzing the gathered data from any device connected to the Internet. This work encompasses the complete solution, a cyber-physical system, starting from the physical level, consisting of sensors and the communication protocol, and reaching data management and storage at the cyber level. The experimental results show that the proposed system represents a viable and straightforward solution for environmental and ambient monitoring applications.

An approach to model dependability of cyber-physical systems

Cyber-Physical Systems (CPSs) represent a new generation of digital systems, where cyber entities and physical devices cooperate towards a set of common goals. The research presented in this paper aims to contribute to the development of CPSs by proposing: (1) an analysis methodology to model the CPSs behavior in terms of dependability; and (2) a CPS architecture with dependability facilities applicable in environmental monitoring, based on the Wireless Sensor Network, multi-agent and cloud computing technologies. The proposed methodology combines a primary dependability analysis technique with the representation of knowledge in order to support the development of CPSs capable to model the dependability at run-time. A dependability domain ontology has been implemented on a CPS case study based on this methodology and its effectiveness has been demonstrated, showing how the proposed approach is able to enhance system dependability. Also, the paper provides a detailed description of each architectural layer of the CPS case study, focusing on the wireless sensor node and on the intelligent decision system.

A cloud-based Cyber-Physical System for environmental monitoring

Cyber-Physical Systems (CPSs) represent a new generation of digital systems, where cyber entities and physical devices cooperate towards a set of common goals. The research presented in this paper aims to contribute to the development of CPSs by proposing an open architecture applicable in environmental monitoring, consisting of three layers. The paper provides a detailed description of each one of the CPSs main components. The bottom layer, composed of wireless sensor nodes, allows the acquisition of data and their transfer to the upper layers. The top and middle layers, composed of a measurements database, a knowledge base, a multi-agent society and web services, assure the proper operation of the CPS based on decision rules and complex data analyses. The proposed architecture provides a high degree of flexibility and scalability.

Integration Techniques of the Embedded Distributed Systems Using Programming Environments and Industrial Standard Communication Protocols

The dispatching process and operative management of the hydro-power plants complex is based on distributed automation architectures hierarchically structured. The plant floor level - technological process interface for data acquisition is represented by programmable logic controllers (PLC) and intelligent measuring devices (embedded systems). The above mentioned devices communicate on industrial data buses with high-performance computers as the logging device. The data processing and storage create the possibility of decisions support for the energy production management and the optimization of the resources exploitation. The data communication between physical resources and structured hierarchical levels is implemented on standard communication protocols (Profibus and Modbus and others) logically driven by OPC mechanism for data source access

Analysis of Three IoT-Based Wireless Sensors for Environmental Monitoring

The recent changes in climate have increased the importance of environmental monitoring, making it a topical and highly active research area. This field is based on remote sensing and on wireless sensor networks for gathering data about the environment. Recent advancements, such as the vision of the Internet of Things (IoT), the cloud computing model, and cyber-physical systems, provide support for the transmission and management of huge amounts of data regarding the trends observed in environmental parameters. In this context, the current work presents three different IoT-based wireless sensors for environmental and ambient monitoring: one employing User Datagram Protocol (UDP)-based Wi-Fi communication, one communicating through Wi-Fi and Hypertext Transfer Protocol (HTTP), and a third one using Bluetooth Smart. All of the presented systems provide the possibility of recording data at remote locations and of visualizing them from every device with an Internet connection, enabling the monitoring of geographically large areas. The development details of these systems are described, along with the major differences and similarities between them. The feasibility of the three developed systems for implementing monitoring applications, taking into account their energy autonomy, ease of use, solution complexity, and Internet connectivity facility, was analyzed, and revealed that they make good candidates for IoT-based solutions.

An agent-oriented approach for cyber-physical system with dependability features

Cyber-physical systems integrate physical and cyber components for high performance, self-maintenance, self-organization, self-assembly, while the process must be dependable, safety, securely, efficiently and in real-time. The research challenges of cyber-physical system are concerning: abstractions and architecture; distributed computation and networked control; verification and validation. This paper aims to meet the development of the cyber-physical systems, especially the ones referring to dependability, by the development of a method for system behaviour evaluation with two aspects: qualitative and quantitative. The quantitative evaluation is made using a multi-agent model that supports an event-driven architecture. The most appropriate methodology - INGENIAS approach - for event-driven multi-agent model development, is selected based on more evaluation criteria. The paper presents the analysis-to-design procedure of the model consisting in the description of the following meta-models: organization, environment, agent, tasks/goals, and interaction.

A Cloud-Integrated, Multilayered, Agent-Based Cyber-Physical System Architecture

The cloud computing infrastructure has the power to increase the dependability, interoperability, and scalability of emerging cyber-physical systems (CPSs). Integrating intelligent agents and semantic ontologies can help manage the complexity of such systems and enable the development of large-scale CPSs.

A data mining experiment on a SCADA system’s historical acquired data

In the SCADA system implemented for a hydroelectric power plants cascade, monitoring, control and over-limit alarm processes provide large amounts of historical data stored in distributed databases. In their preliminary form these data donpsilat offer a performance knowledge discovery. Intelligent data mining framework applied over historical acquired data is used to extract hidden information directly from the SCADA systempsilas database records. This paper presents a data mining and visualization experiment performed on a real data and results achieved in the experiment. The decision trees algorithm is used in order to find patterns in historical data and to establish a data mining flow.

Cyber-physical system dependability enhancement through data mining

The research presented in the current paper addresses the use of data mining techniques for enhancing the dependability characteristic in the case of cyber-physical systems. A cyber-physical system for environmental monitoring was considered as a case study. In this context, the main task of data mining is to predict the missing sensor values caused by hardware and software components malfunctions. Different versions of a data mining regression algorithm were tested on the case study system, based on a well known data mining methodology. The test results show that the algorithms taken into consideration can predict sensor data with satisfactory accuracy, leading to a decreased failure rate of the system.