Game-based Synthesis of Distributed Controllers for Sampled Switched Systems

Switched systems are a convenient formalism for modeling physical processes interacting with a digital controller. Unfortunately, the formalism does not capture the distributed nature encountered e.g. in cyber-physical systems, which are organized as networks of elements interacting with local controllers. Most current methods for control synthesis can only produce a centralized controller, which is assumed to have complete knowledge of all the component states and can interact with all of them. In this paper, we consider a centralized-controller synthesis technique based on state-space decomposition, and use a game-based approach to extend it to a distributed framework

Integrating OPC Data into GSN Infrastructures

This paper presents the design and the implementation of an interface software component between OLE for Process Control (OPC) formatted data and the Global Sensor Network (GSN) framework for management of data from sensors. This interface, named wrapper in the GSN context, communicates in Data Access mode with an OPC server and converts the received data to the internal GSN format, according to several temporal modes. This work is realized in the context of a Ph.D. Thesis about the control of distributed information fusion systems. The developed component allows the injection of OPC data, like measurements or industrial processes states information, into a distributed information fusion system deployed in a GSN framework. The component behaves as a client of the OPC server. Developed in Java and based on the Opensaca Utgard, it can be deployed on any computation node supporting a Java virtual machine. The experiments show the component conformity according to the Data Access 2.05a specification of the OPC standard and to the temporal modes

A Distributed Hierarchical Framework for Autonomous Spacecraft Control

Future human space missions for exploring beyond low Earth orbit are in the conceptual design stage. One such mission describes a habitat in cis-lunar orbit that is visited by crew periodically, others describe missions to Mars. These missions have one important thing in common: the need for autonomy on the spacecraft. This need stems from the latency and bandwidth constraints on communications between the vehicle and ground control. A variable amount of autonomy may be necessary whether the spacecraft has crew on board or not. Spacecraft are complex systems that are engineered as a collection of subsystems. These subsystems work together to control the overall state of the spacecraft. As such, solutions that increase the autonomy of the spacecraft (called autonomous functions) should respect both the independence and interconnectedness of the spacecraft subsystems. This distributed and hierarchical approach to system monitoring and control is a key idea in the Modular Autonomous Systems Technology (MAST) framework. The MAST framework enables a component-based architecture that provides interfaces and structure to developing autonomous technologies. The framework enforces a distributed, hierarchical architecture for autonomous control systems across subsystems, systems, elements, and vehicles. An example autonomous system was implemented in this framework and tested using realistic spacecraft software and hardware simulations. This paper will discuss the framework, tests conducted, results, and future work

Simulation System for the Wendelstein 7-X Safety Control System

The Wendelstein 7-X (W7-X) Safety Instrumented System (SIS) ensures personal safety and investment protection. The development and implementation of the SIS are based on the international safety standard for the process industry sector, IEC 61511. The SIS exhibits a distributed and hierarchical organized architecture consisting of a central Safety System (cSS) on the top and many local Safety Systems (lSS) at the bottom. Each technical component or diagnostic system potentially hazardous for the staff or for the device is equipped with an lSS. The cSS is part of the central control system of W7-X. Whereas the lSSs are responsible for the safety of each individual component, the cSS ensures safety of the whole W7-X device. For every operation phase of the W7-X experiment hard- and software updates for the SIS are mandatory. New components with additional lSS functionality and additional safety signals have to be integrated. Already established safety functions must be adapted and new safety functions have to be integrated into the cSS. Finally, the safety programs of the central and local safety systems have to be verified for every development stage and validated against the safety requirement specification. This contribution focuses on the application of a model based simulation system for the whole SIS of W7-X. A brief introduction into the development process of the SIS and its technical realization will be give followed by a description of the design and implementation of the SIS simulation system using the framework SIMIT (Siemens). Finally, first application experiences of this simulation system for the preparation of the SIS for the upcoming operation phase OP 1.2b of W7-X will be discussed

Specification and Analysis of Information Flow Properties for Distributed Systems

We present a framework for the speci?cation and the analysis of infor- mation ?ow properties in partially speci?ed distributed systems, i.e., sys- tems in which there are several unspeci?ed components located in di?erent places. First we consider the notion of Non Deducibility on Composition (NDC for short) originally proposed for nondeterministic systems and based on trace semantics. We study how this information ?ow property can be extended in order to deal also with distributed partially speci?ed systems. In particular, we develop two di?erent approaches: the cen- tralized NDC (CNDC) and the decentralized NDC (DNDC). According to the former, there is just one unspeci?ed global component that has complete control of the n distributed locations where interaction occurs between the system and the unspeci?ed component. According to DNDC, there is one unspeci?ed component for each distributed location, and the n unspeci?ed components are completely independent, i.e., they cannot coordinate their e?orts or cooperate. Surprisingly enough, we prove that centralized NDC is as discriminating as decentralized NDC. However, when we move to Bisimulation-based Non-Deducibility on Composition, BNDC for short, the situation is completely di?erent. We prove that centralized BNDC (CBNDC for short) is strictly ?ner than decentralizedBNDC (DBNDC for short), hence proving the quite expected fact that a system that can resist to coordinated attacks is also able to resist to simpler attacks performed by independent entities. Hence, by exploiting a variant of the modal ?-calculus that permits to manage tuples of ac- tions, we present a method to analyze when a system is CBNDC and/or DBNDC, that is based on the theory of decomposition of formulas and compositional analysis

The Proviado Access Control Model for Business Process Monitoring Components

Integrated process support is highly desirable in environments where data related to a particular business process are scattered over distributed, heterogeneous information systems. A business process monitoring component is a much-needed module in order to provide an integrated view on all these process data. Regarding process visualization and process data integration, access control (AC) issues are very important but also quite complex to be addressed. A major problem arises from the fact that the involved information systems are usually based on heterogeneous AC components. For several reasons, the only feasible way to tackle the problem of AC at the process monitoring level is to define access rights for the process monitoring component, hence getting rid of the burden to map access rights from the information system level. This paper presents the Proviado process visualization framework and discusses requirements for AC in process monitoring, which we derived from our case studies in the automotive domain. It then presents alternative approaches for AC: the view-based and the object-based approach. The latter is retained, and a core AC model is proposed for the definition of access rights that meet the derived requirements. AC mechanisms provided within the core model are key ingredients for the definition of model extensions

From the Queue to the Quality of Service Policy: A Middleware Implementation

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-02481-8_61Quality of service policies in communications is one of the current trends in distributed systems based on middleware technology. To implement the QoS policies it is necessary to define some common parameters. The aim of the QoS policies is to optimize the user defined QoS parameters. This article describes how to obtain the common QoS parameters using message queues for the communications and control components of communication. The paper introduces the Queue-based Quality of Service Cycle concept for each middleware component. The QoS parameters are obtained directly from the queue parameters, and Quality of Service Policies controls directly the message queues to obtain the user-defined parameters values.The middleware architecture described in this article is a part of the coordinated project SIDIRELI: Distributed Systems with Limited Resources. Control Kernel and Coordination. Education and Science Department, Spanish Government. CICYT: MICINN: DPI2008-06737-C02-01/02.Poza-Lujan, J.; Posadas-Yagüe, J.; Simó Ten, JE. (2009). From the Queue to the Quality of Service Policy: A Middleware Implementation. En Distributed Computing, Artificial Intelligence, Bioinformatics, Soft Computing, and Ambient Assisted Living. Springer Verlag (Germany). 432-437. doi:10.1007/978-3-642-02481-8_61S432437Aurrecoechea, C., Campbell, A.T., Hauw, L.: A Survey of QoS Architectures. Multimedia Systems Journal, Special Issue on QoS Architecture 6(3), 138–151 (1998)OMG. Data Distribution Service for Real-Time Systems, v1.1. Document formal/2005-12-04 (December 2005)Botts, M., Percivall, G., Reed, C., Davidson, J.: OGC®. Sensor Web Enablement: Overview And High Level Architecture, OpenGIS Consortium Inc (2006)Poza, J.L., Posadas, J.I., Simó, J.E.: QoS-based middleware architecture for distributed control systems. In: International Symposium on Distributed Computing and Artificial Intelligence, Salamanca (2008)Vogel, A., Kerherve, B., von Bochmann, G., Gecsei, J.: Distributed Multi-media and QoS: A Survey 2(2), 10–19 (1995)Crawley, E., Nair, R., Rajagopalan, B.: RFC 2386: A Framework for QoS-based Routing in the Internet, pp. 1–37, XP002219363 (August 1998)ITU-T Recommendation E.800 (0894). Terms and Definitions Related to Quality of Service and Network Performance Including Dependability (1994)Stuck, B.W., Arthurs, E.: A Computer & Communications Network Performance Analysis Primer. Prentice Hall, Englewood Cliffs (1984)Jain, R.: The art of Computer Systems Performance Analysis. John Wiley & Sons Inc., New york (1991)Coulouris, G., Dollimore, J., Kindberg, T.: Distributed Systems. Concepts and Design, 3rd edn. Addison Wesley, Madrid (2001)Jung, J.-l.: Quality of Service in Telecommunications Part II: Translation of QoS Pa-rameters into ATM Performance Parameters in B-ISDN. IEEE Comm. Mag., pp. 112–117 (August 1996)Wohlstadter, E., Tai, S., Mikalsen, T., Rouvellou, I., Devanbu, P.: GlueQoS: Middleware to Sweeten Quality-of-Service Policy Interactions. In: ICSE, 26th International Conference on Software Engineering (ICSE 2004) (2004

JSB Composability and Web Services Interoperability Via Extensible Modeling & Simulation Framework (XMSF), Model Driven Architecture (MDA), Component Repositories, and Web-based Visualization

Study Report prepared for the U. S. Air Force, Joint Synthetic Battlespace Analysis of Technical Approaches (ATA) Studies & Prototyping Overview: This paper summarizes research work conducted by organizations concerned with interoperable distributed information technology (IT) applications, in particular the Naval Postgraduate School (NPS) and Old Dominion University (ODU). Although the application focus is distributed modeling & simulation (M&S) the results and findings are in general easily applicable to other distributed concepts as well, in particular the support of operations by M&S applications, such as distributed mission operations. The core idea of this work is to show the necessity of applying open standards for component description, implementation, and integration accompanied by aligned management processes and procedures to enable continuous interoperability for legacy and new M&S components of the live, virtual, and constructive domain within the USAF Joint Synthetic Battlespace (JSB). JSB will be a common integration framework capable of supporting the future emerging simulation needs ranging from training and battlefield rehearsal to research, system development and acquisition in alignment with other operational requirements, such as integration of command and control, support of operations, integration of training ranges comprising real systems, etc. To this end, the study describes multiple complementary Integrated Architecture Framework approaches and shows, how the various parts must be orchestrated in order to support the vision of JSB effectively and efficiently. Topics of direct relevance include Web Services via Extensible Modeling & Simulation Framework (XMSF), the Object Management Group (OMG)’s Model Driven Architecture (MDA), XML-based resource repositories, and Web-based X3D visualization. To this end, the report shows how JSB can − Utilize Web Services throughout all components via XMSF methodologies, − Compose diverse system visualizations using Web-based X3D graphics, − Benefit from distributed modeling methods using MDA, and − Best employ resource repositories for broad and consistent composability. Furthermore, the report recommends the establishment of necessary management organizations responsible for the necessary alignment of management processes and procedures within the JSB as well as with neighbored domains. Continuous interoperability cannot be accomplished by technical standards alone. The application of technical standards targets the implementation level of the system of systems, which results in an interoperable solution valid only for the actual 2 implementation. To insure continuity, the influence of updates, upgrades and introduction of components on the system of systems must be captured in the project management procedures of the participating systems. Finally, the report proposes an exemplifying set of proof-of-capability demonstration prototypes and a five-year technical/institutional transformation plan. All key references are online available at http://www.movesinstitute.org/xmsf/xmsf.html (if not explicitly stated otherwise)