Communicating Processes with Data for Supervisory Coordination

We employ supervisory controllers to safely coordinate high-level discrete(-event) behavior of distributed components of complex systems. Supervisory controllers observe discrete-event system behavior, make a decision on allowed activities, and communicate the control signals to the involved parties. Models of the supervisory controllers can be automatically synthesized based on formal models of the system components and a formalization of the safe coordination (control) requirements. Based on the obtained models, code generation can be used to implement the supervisory controllers in software, on a PLC, or an embedded (micro)processor. In this article, we develop a process theory with data that supports a model-based systems engineering framework for supervisory coordination. We employ communication to distinguish between the different flows of information, i.e., observation and supervision, whereas we employ data to specify the coordination requirements more compactly, and to increase the expressivity of the framework. To illustrate the framework, we remodel an industrial case study involving coordination of maintenance procedures of a printing process of a high-tech Oce printer.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432

International Framework for Liquidity Risk Measurement,Standards and Monitoring:Corporate Governance and Internal Controls

This paper is structured in accordance with identified components which are considered to be essential to the successful implementation of the (two fold) topics of discussion of this paper, namely, monitoring and liquidity risk measurements. The importance of successfully communicating results obtained from monitoring and measuring such risks, and the role of corporate governance in ensuring such effective communication, constitutes a recurring theme throughout this paper. The identified components are as follows: i) Corporate governance (ii) Internal controls (iii) Disclosure (iv) Management of risk (v) Substance over form (vi) Transparency As well as highlighting the interdependence of these components, the paper also aims to accentuate the importance of individual components. Whilst no hierarchy of importance is assigned to these components, corporate governance and internal controls are two components which are analysed in greater depth (than other components). Furthermore, corporate governance could be accorded a status of greater importance than internal controls having regard to the fact that whilst internal controls relate to a very vital control aspect of an organisation, corporate governance relates to all processes – be it decision making, control, production, performance, within a company/bank. The paper will also attempt to demonstrate that it is possible to implement a system of regulation which combines increased formalised procedures and/or detailed rules - whilst giving due consideration to the substance of transaction

Modular synthesis of discrete controllers

This paper presents supervisory control theory in a process-algebraic setting, and proposes a way of synthesising modular supervisors that guarantee nonblocking. The framework used includes the possibility of hiding actions which results in nondeterminism. As modularity crucially depends on the process equivalence used, the paper studies possible equivalences and points out that, in order to be consistent with respect to the nonblocking property and to supervisor synthesis, a conflict-preserving equivalence must be used. It applies the results to synthesise nonblocking modular supervisors for a manufacturing system

Real-time and fault tolerance in distributed control software

Closed loop control systems typically contain multitude of spatially distributed sensors and actuators operated simultaneously. So those systems are parallel and distributed in their essence. But mapping this parallelism onto the given distributed hardware architecture, brings in some additional requirements: safe multithreading, optimal process allocation, real-time scheduling of bus and network resources. Nowadays, fault tolerance methods and fast even online reconfiguration are becoming increasingly important. All those often conflicting requirements, make design and implementation of real-time distributed control systems an extremely difficult task, that requires substantial knowledge in several areas of control and computer science. Although many design methods have been proposed so far, none of them had succeeded to cover all important aspects of the problem at hand. [1] Continuous increase of production in embedded market, makes a simple and natural design methodology for real-time systems needed more then ever

International framework for liquidity risk measurement, standards and monitoring: corporate governance and internal controls

This paper is structured in accordance with identified components which are considered to be essential to the successful implementation of the (two fold) topics of discussion of this paper, namely, monitoring and liquidity risk measurements. The importance of successfully communicating results obtained from monitoring and measuring such risks, and the role of corporate governance in ensuring such effective communication, constitutes a recurring theme throughout this paper. The identified components are as follows: i) Corporate governance (ii) Internal controls (iii) Disclosure (iv) Management of risk (v) Substance over form (vi) Transparency As well as highlighting the interdependence of these components, the paper also aims to accentuate the importance of individual components. Whilst no hierarchy of importance is assigned to these components, corporate governance and internal controls are two components which are analysed in greater depth (than other components). Furthermore, corporate governance could be accorded a status of greater importance than internal controls having regard to the fact that whilst internal controls relate to a very vital control aspect of an organisation, corporate governance relates to all processes – be it decision making, control, production, performance, within a company/bank. The paper will also attempt to demonstrate that it is possible to implement a system of regulation which combines increased formalised procedures and/or detailed rules - whilst giving due consideration to the substance of transactions.corporate governance; internal controls; monitoring; liquidity; regulation

Software for Embedded Control Systems

The research of our team deals with the realization of control schemes on digital computers. As such the emphasis is on embedded control software implementation. Applications are in the field of mechatronic devices, using a mechatronic design approach (the integrated and optimal design of a mechanical system and its embedded control system). The ultimate goal is to support the application developer (i.e. mechatronic design engineer) such that implementing control software according to ðo it the first time right¿ becomes business as usual

Hierarchical interface-based supervisory control using the conflict preorder

Hierarchical Interface-Based Supervisory Control decomposes a large discrete event system into subsystems linked to each other by interfaces, facilitating the design of complex systems and the re-use of components. By ensuring that each subsystem satisfies its interface consistency conditions locally, it can be ensured that the complete system is controllable and nonblocking. The interface consistency conditions proposed in this paper are based on the conflict preorder, providing increased flexibility over previous approaches. The framework requires only a small number of interface consistency conditions, and allows for the design of multi-level hierarchies that are provably controllable and nonblocking