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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.

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.

Intelligent agents and BIST/BISR - working together in distributed systems

This paper presents an attempt of using intelligent agents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (built-in self-test) and BISR (built-in self-repair) facilities. The agents are software modules that perform monitoring, diagnosis and repair of the faults. Together they form a society whose members communicate, set goals and solve tasks. To demonstrate the idea we used the Zeus agent development environment. Two examples of distributed systems are presented in order to illustrate the cooperative model for fault diagnosis and repair.

Wi-sensors: A low power Wi-Fi solution for temperature and humidity measurement

This paper presents a complete solution for temperature and humidity monitoring using low-power wireless devices, called Wi-Sensors. The Wi-Sensors use a RN-131C Wi-Fi chip as the core microcontroller and 4 configurable digital input/output lines to which temperature sensors can be attached. The digital 1-Wire and DHT22 protocols had been implemented in the embedded application running on the device. Therefore, for temperature and humidity measurements, any of the sensors operating with one of these two protocols can be used. The existing Wi-Fi 802.11 infrastructure can be used in order to send measurement data to remote destinations. The proposed solution also incorporates a data viewer and data processing application, which provides functionalities for alarming the users by email or by SMS in case previously configured limits are exceeded.

Database Globalization in Enterprise Applications

The globalization of a Web application requires storing and accessing data needed by or received from users in different cultures. This paper analyzes three approaches to applying globalization to database models, for flexible support of various locales

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.

Unidirectional error detection, localization and correction for DRAMs: Application to on-line DRAM repair strategies

A novel family of codes for the detection, localization and correction of unidirectional errors for DRAMs in proposed. For DRAM memories, multi-bit soft and hard errors are a growing concern, as the cell sizes continue to decrease with aggressive scaling down. As a result, the classical error detection/correction codes become less efficient to deal with multiple errors in a single word [16]. Berger codes are effective in detecting 100% of the unidirectional errors, but introduce considerable delay and does not provide any error correction feature. In order to decrease the computing time of the code check bits and, at the same time, to provide the possibility to localize the segment(s) where single or multiple errors have occurred, a modification of the Berger code is proposed, called Carry Save K Berger code (CS-K Berger). Basically consists in using Carry Save representations of the partial additions of the word segments. The number of check bits increases as compared with Berger code and consequently the code redundancy overhead increases but the delay in computing the check bits and the corresponding checking is drastically reduced. In addition, some patterns of unidirectional errors become correctable. The proposed CS-K Berger codes for different values of K are analyzed for different word lengths. The hardware required for code generation and verification is discussed as well, as the possibility of using this code for word segment replacement in online applications of DRAMs.

Local EHR Management Based on openEHR and EN13606

This article describes handling medical data in a healthcare system based on electronic healthcare records. At a medical unit level, data storage requires both accurate collecting and high security. The proposed information model complies with EN 13606, which is a European health data communication standard approved by the European Committee for Standardization (CEN) and partly approved by the International Organization for Standardization (ISO).

Enhancing security in cyber-physical systems through cryptographic and steganographic techniques

Information technology is continually changing, discoveries are made every other day. Cyber-physical systems consist of both physical and computational elements and are becoming more and more popular in todays society. They are complex systems, used in complex applications. Therefore, security is a critical and challenging aspect when developing cyber-physical systems. In this paper, we present a solution for ensuring data confidentiality and security by combining some of the most common methods in the area of security - cryptography and steganography. Furthermore, we use hierarchical access to information to ensure confidentiality and also increase the overall security of the cyber-physical system.