Matjaz Colnaric

• Prof. Dr.
• Chair at University of Maribor - Faculty of El Eng & Comp Sci

Fault-tolerant industrial systems need effective fault detection, which we can treat as a classification problem based on the observable system properties. Artificial neural networks (ANN) are provenly strong contenders in this field, capable of supervised learning from experience. They operate with large amounts of data, which we need to prepare a...

This chapter introduces some devised solutions for fault detection within embedded control systems. These are a follow-on to the successful IST FW5 project IFATIS at the Laboratory for Real-Time Systems of the Faculty of Electrical Engineering and Computer Science. The topic will first be elaborated on and the overall results of the original projec...

This Milestone Report addresses first the position of the areas of computers, computational intelligence and communications within IFAC. Subsequently, it addresses the role of computational intelligence in control. It focuses on four topics within the Computational Intelligence area: neural network control, fuzzy control, reinforcement learning and...

In this contribution, a short overview of our early collaboration with Prof. Halang is given. Our joint research is briefly described and some results presented. First, prerequisite considerations are given, then the asymmetrical architecture exhibiting a dedicated processor for operating system kernel functions is outlined. Its design is further e...

A safety shell for real-time applications to be developed with UML is defined based on a re-configuration management pattern. Inspired by the architectural specifications in the Specification PEARL methodology, the pattern is parameterised by defining the properties of its components as well as by defining how the software is to be mapped to the ha...

A reconfiguration pattern for UML-based projects of embedded (real-time) systems is defined. It enables to set up hardware/software configurations, and to specify conditions and methods for dynamic reconfiguration. The reconfiguration pattern was inspired by the reconfiguration management solution of the Specification PEARL methodology, which is ba...

In this chapter it is shown how the platform has been employed in the implementation of an intelligent re-configurable fault-tolerant control system within the research project [62].

Similar to the development in other domains of embedded systems, in practice control applications are often programmed by improper means. For a number of pragmatic reasons, the same methods, techniques, and programming languages as for general-purpose desktop applications are employed. One of the reasons for this is common knowledge of programming:...

Tasks (or computing processes) are the smallest entities and fundamental elements of asynchronous programming. They represent the execution of programs in a computing system during the lifetime of the processes. Such a lifetime begins with the registration instant of a process and ends with its cancellation. Thus, the computing process exists not o...

Hardware architectures and their implementations provide the lowest level of control system design. Regarding the microscopic predictability approach [105], the higher layers of real-time systems are only predictable if the lower ones are. For that reason, extreme care ought to be taken when selecting approaches, guidelines, technologies and, parti...

Very often, practical design of embedded systems lacks consistency resulting in computer control systems that do not provide the performance they should. Most notably they lack dependability, a key property now that programmed electronic devices are so pervasive, even in extremely safety-critical applications. Distributed Embedded Control Systems h...

In the chapter, fault detection in embedded control systems is elaborated. The basic idea is to monitor input and output variables, and internal states of such systems, processes or subprocesses by acquired and built in knowledge about the normal behavior to detect abnormalities. The proposed model is intended to deal with faults in the environment...

Paper presents fault detection in embedded control systems by the so-called monitoring cells. The basic idea is to monitor input/output variables and internal states of systems, processes or sub-processes by using acquired and built-in knowledge about the normal behavior in order to detect abnormalities. Paper gives the detailed architecture and th...

In the paper, fault detection in embedded control systems will be elaborated. The basic idea is to monitor input and output variables, and internal states of such systems, processes or sub-processes by acquired and built in knowledge about the normal behaviour in order to detect abnormalities. The proposed model is intended to deal with faults in t...

A reconfiguration management pattern for UML real-time projects inspired by the Specification PEARL methodology is defined. It is parameterised by defining the properties of its components as well as by defining how the software is mapped to the hardware architecture. The pattern itself is a UML representation of a Specification PEARL architectural...

This article analyses two most commonly used distributed models in Java: Web services and RMI (Remote Method Invocation). The paper focuses on regular (unsecured) as well as on secured variants, WS-Security and RMI–SSL. The most important functional differences are identified and the performance on two operating systems (Windows and Linux) is compa...

In this paper a description of a consistent design of an embedded hard real-time control system is given. To provide for the overall predictability of tasks' temporal behaviour, which is the ultimate requirement in such systems, all influencing factors are taken into account in a holistic manner: system and hardware architecture, operating system i...

An autonomous evolutionary algorithm for constructing decision trees is presented. The algorithm requires no or minimal human interaction and shows some interesting properties when used on different medical datasets. The algorithm uses a non-standard implicit fitness evaluation in the selection phase of a co-evolving environment. Together with self...

When dealing with distributed control systems, the notions of nodes, messages, timetables, etc. are usually not transparent from the control application designer view. For that reason, in the IFATIS platform, the distributed shared memory model has been introduced to decouple the control application design from the issues of the hardware implementa...

An approach to hardware/software codesign and verification is presented. Hardware and software are modeled with the specification PEARL language, which has its origins in standard multiprocessor PEARL. Its usefulness has been enhanced for hierarchical and asymmetrical multiprocessor system modeling, and by additional parameters for schedulability a...

The paper presents some guidelines supported by a case study of a design of a fault tolerant computer control system. It was devised and implemented as a laboratory platform for the 5th framework project IFATIS. Instead of the redundancy, in this project it is proposed to deal with faults by dynamic reconfiguration of the resources that are still v...

An approach to holistic system modelling is presented, based on the Specification PEARL hardware/software co-design methodology, having its origin in the standard Multiprocessor PEARL specification language. Specification PEARL specifications and models represent prototypes of systems and programs, based on the PEARL program model. The system model...

This paper gives an overview of a holistic project dealing with the consistent design of embedded control systems falling into the first level of safety integrity requirements (SIL l) (IEC, 1998). It shows how existing methods can be adapted and reasonably employed, whenever possible, without having to resort to new innovations. Firstly, the hardwa...

An autonomous evolutionary framework for construction of decision trees that requires no or minimal human interaction is presented. The framework evolves two types of agents which hold the discovered knowledge, and uses a non-standard implicit fitness evaluation in a co-evolving environment. Together with self-adaptation of evolutionary parameters...

Computer Aided and Integrated Manufacturing Systems rely heavily on the techniques of Mechatronics System. These systems consist of three main physical components — viz., mechanical, electrical and computer subsystems. The latter are often called embedded computer control systems. By definition they operate in the hard real-time domain, i.e., they...

In the paper, some discussion of the implementation of a fault-tolerant hardware platform is presented. The discussion is focused on the control applications with less severe integrity requirements (SIL1) and where the intelligent system reconfiguration is preferred (instead of the redundancy) in the case of failures.

In the paper, a communication infrastructure for fault-tolerant embedded control system is discussed. It was de-veloped as a part of experimental platform of the IFATIS project within the 5th European Union framework pro-gramme, dealing with dependable, reconfigurable inte-grated control systems. In such environments, a reliable and robust physical...

In the paper an application for demonstration and analysis of data structures and sorting algorithms is presented. Their operation can be animated and demonstrated on asserted or generated input data, with different statistical distributions. Analysis of the performance and of the complexity of various algorithms can be calculated and/or measured.

In the paper, a proposition for a systematic approach to fault detection in building a dependable and fault-tolerant control system is presented. A network of simple monitoring cells that monitor and evaluate functioning of critical sub-processes of the system is proposed. Further, different approaches for the implementation of the monitoring cells...

In embedded hard real-time systems, tasks must complete their executions within predefined time frames. A necessary pre-condition to achieve this requirement is predictability of their temporal behaviour. Here, the main focus is on handling exceptions in such systems. When handled in a classical way, they necessarily jeopardise the ultimate require...

This paper gives an overview of a holistic project dealing with the consistent design of embedded control systems with special emphasis on their integrity aspects. It shows how existing methods can be adapted and reasonably employed, whenever possible, without having to resort to new innovations. Firstly, the hardware issues are dealt with and exte...

First generation expert systems were using shallow knowledge based on heuristic information to solve a diagnostic problem. This approach has many disadvantages, which can be avoided by using deep knowledge. Diagnostic reasoning based on deep knowledge is called model-based diagnostics. Recently, the use of qualitative modeling in relation to deep k...

In the article a HW/SW co-design methodology is presented, which enables early reasoning about system integration as well as verification of the designs. Specification PEARL methodology is based on a specification language with the same name, whose origins are in the standard Multiprocessor PEARL language. It has been enhanced by additional compone...

An approach to the modeling and verification of real-time systems is presented. The Specification PEARL description language is used for hardware/software modeling. It has its origins in the standard Multiprocessor PEARL language. Its usefulness has been enhanced for asymmetrical multiprocessor system modeling, and parameters for schedulability ana...

This paper deals with the overload caused by excessive service requests from the environment for dynamic control systems. A method of providing gracefully degraded solutions is proposed, based on the previous work on the project dealing with the design of a consistent embedded real-time control system with the goal of increasing its dependability....

This paper deals with the possibility of introducing exception handling mechanisms into the specification and code of industrial process control software. Although exception handling is a very important aspect of process control applications, in most cases it is treated in an ad hoc and unstructured manner — which is mainly caused by the lack of ap...

The architecture of a programmable controller especially suited for automation applications of highest safety criticality, i.e., on Safety Integrity Level 4, is presented. Its main characteristics are input conditioning by low resolution analogue-to-digital converters and inference by look-up in cause/effect tables or rule set tables. This programm...

In the paper some experiences of joining two methodologies, which were originally independently developed in different institutions, with the goal to overcome the possible discrepancies due to the separate design of the hardware and the software part of an embedded real-time application are presented. Based on Multiprocessor PEARL, Specification PE...

Hard real-time systems are increasingly used in various areas of human activity justifying their implementation by means of specialized solutions, mostly of a suitable hardware/software combination. A frequently adopted approach to the realization of the hardware part is based on ASIC, usually a “general purpose” processor which operates according...

The present state of practical implementations of embedded control systems does not in all aspects match the guidelines set by academic real-time systems research. With an implementation of peripheral units and interfaces it is exemplified how improvements can be achieved employing standard means and off-the-shelf components.

So far, performance measures for real time systems did not receive much attention. An assessment of the few existing benchmarking methods for real time systems will reveal that they are highly inappropriate. Taking a closer look into the fundamental issues of real time systems it will become clear, that for hard real time systems qualitative charac...

There is evidence that, among all design domains of hard real time systems, architectural issues gained the lowest research interest. Universal architectures, which are generally applied as hardware bases for hard real time applications, are seldom behaving in a fully predictable way. In the paper, several commonly used techniques which prevent tem...

The concept of the kernel, i.e. the time critical part of a real-time operating system, and its dedicated co-processor, especially tailored for embedded applications, are presented. The co-processor acts as a system controller and operates in conjunction with one or more conventional processors in hard real-time environments. It is composed of thre...

To ensure temporally predictable execution behaviour of an embedded hard real-time computer control system, layer-by-layer predictability of the system must be provided. Based on a simple structured programming language, a programming environment for hard real-time applications is under construction designed to function temporally predictably, and...

this paper is to present a method for handling non-preventable and nonavoidable

The most important and necessary properties of embedded real-time systems, and the ways to achieve them, are explored. The basic and most important domains of real-time systems design are dealt with, starting with the processor and system hardware architectures, over operating systems, tasking and scheduling, high-level real-time programming langua...

Hard real-time systems are increasingly used in various areas of human activities. They are often implemented by means of specialized solutions, mostly of a suitable hardware/software combination. A frequently adopted approach to the realization of the hardware part is based on ASIC, usually a “general purpose” processor which operates according to...

The goal of this paper is to find the most efficient architecture for distributed and adaptive systems that could provide services, which have to be executed within a given time frame. A real-time client/server architecture is proposed. This paper focuses on the server part of the architecture, the real-time server object (RTSO). Within this archit...

In the paper the possibility of using a real-time programming language to formulate hardware and software specifications is elaborated. Instead of using strict formal specifications, a system is described in a simple and straight-forward manner, using terminology which is close to the application programmer and his or her way of thinking. The descr...

An approach to the design of hard real-time system software, specifically operating system kernels, is suggested. It is pragmatic in nature: using an usual non-real-time off-the-shelf software development tool, system routines are developed, debugged and pre-tested using breakpoints, code tracing, etc.

A novel design for a computer control system to be employed in safety critical applications, as found in medical environments, is presented. It features a low complexity, fault detecting hardware architecturally supporting a strictly cyclic operating mode, as known from programmable logic controllers, and a specification level, graphical programmin...

Although the domain of hard real-time systems has been thoroughly elaborated in the academic sphere, embedded computer control systems –- being an important component in mechatronic designs –- are seldom dealt with consistently. Often, off-the-shelf computer systems are used, with no guarantee that they will be able to meet the requirements specifi...

Real-time Systems and embedded systems in particular have, until recently, been built as works of art. Standard hardware components only are now being used and scalable standardized operating systems are being built. There have been many attempts to simplify the design of these systems through the use of standard mechanisms and components, but many...

Although the domain of hard real-time systems has been thoroughly elaborated in the academic sphere, embedded computer control systems — being an important component in mechatronic designs — are seldom dealt with consistently. Often, off-the-shelf computer systems are used, with no guarantee that they will be able to meet the requirements specified...

The design of the hardware, the software and the operating system for real-time applications is studied. To achieve the necessary properties and performance, it is proposed to co-design the constituents in a holistic way. An attempt is made to unify the design and development approaches. A modified spiral model of the design lifecycle is adopted wh...

So far, performance measures for real time systems did not receive much attention. An assessment of the few existing benchmarking methods for real time systems will reveal that they are highly inappropriate. Taking a closer look into the fundamental issues of real time systems it will become clear, that for hard real time systems qualitative charac...

Safety critical computer control systems are dealt with, which can be employed in medical applications. Safety licensing of such systems, especially of their software parts, is extremely difficult and for the time being almost impossible except for the trivial cases. In the presented approach, the article proposes how to design both the hardware an...

. In this paper a description of a consistent design of an embedded hard real-time control system is given. To provide for the overall predictability of tasks' temporal behaviour, which is the ultimate requirement in such systems, all influencing factors are taken into account in a holistic manner: system and hardware architecture, operating system...

To assure temporal predictability in embeded hard real-time programing, layer-by-layer predictability of the system must be provided. Experimental hardware platform and coresponding operating system are being designed and built. Parallet to this, a programing environment for hard real-time systems is under construction, based on a simple structured...

A possibility of using a real-time programming language to formulate hardware and software specifications is elaborated. Instead of using strict formal specifications, a system is described in a simple and straightforward manner using a terminology which is close to the application programmer and his or her way of thinking. The description is a mix...

The architecture of a fuzzy controller especially suited for safety-critical applications such as temperature control in nuclear reactors is developed. Its main chacteristics are fuzzification by low-resolution analogue-to-digital converters and inference by look-up in a table containing a fuzzy rule set. Although originally based on fuzzy logic, t...

Für im harten Echtzeitbetrieb arbeitende eingebettete Systeme ist es von größter Wichtigkeit, sicherstellen zu können, daß aus der einbettenden Umgebung kom­mende Anforderungen innerhalb vorgegebener Antwortzeiten bedient werden. Im Mehrprozeßbetrieb kann diese Forderung als Zuteilbarkeit ausgedrückt werde: die Existenz eines Ablaufplanes dergestal...

A graphical software development paradigm is presented deviating from classical techniques by enforcing the (re-) use of pre-engineered and a priori verified off-the-shelf application-oriented standard software function blocks. It is based on long established practice in control engineering. For certain industrial application areas specific functio...

Participants introduced themselves briefly, describing their major activities and interest regarding teaching “Real-Time Systems” courses, as well as their expectations regarding the work of this group. Remarkably, attending participants formed a mixture of faculty from Computer Engineering, Computer Science, and Electrical Engineering departments.

In Slovenia, computer science and control systems research have a non-neglectable tradition. In the last time also the domain of real-time computing is significantly gaining interest. The research is mainly done in the two universities, several scientific institutes and industrial R&D laboratories.

In contrast to most of the other studies which only consider selected topic(s) and typically deal with issues of higher levels of design, the research project outlined uses a holistic approach to real-time application design issues. It is set up in layers starting with a predictably behaving computer hardware architecture, followed by an appropriat...

The objective of this paper is to give some reflections about handling of exceptions in hard real-time environments, which is among the less elaborated topics in this domain. A classification of possible exceptions in real-time systems is done, to identify the ones which can be prevented by certain design measures or avoided by specifying and servi...

There is evidence that, among all design domains of hard real time systems, architectural issues gained the lowest research interest. Universal architectures, which are generally applied as hardware bases for hard real time applications, are seldom behaving in a fully predictable wav. In the paper, several commonly used techniques which prevent tem...

The timing predictability of hard real-time systems can only be assured if every component behaves deterministically. Various system design issues are stressed, from system and processor architecture to language and exception handling. In the field of architecture, some design recommendations are given and a timing predictability study of microproc...

Timing predictability of the hard real-time systems can only be assured if every feature of them is deterministic. In this paper, various system design issues are stressed, from the system and processor architecture, to the language and exception handling. In the field of architecture, some design recommendations are given and a timing predictabili...

A comparison of state and event observation techniques that lead to a periodic, time driven operating system are given. A brief description of the system and hardware is presented. A description of the objectives and goals of the operating system and its implementations. Some applications are enumerated, and the conclusion contains discussion on th...