Proceedings
of the Fifth International
Workshop on Functional Modeling
of Complex Technical Systems
(ISSN 1089-7372) (ISBN
0-9652669-5-8) (Total 247 Pages)
Fifth
International Workshop
Paris-Troyes,
France
July 1 -
3, 1997
Edited by:
Mohammad
Modarres
Center for Technology Risk
Studies
University of Maryland
2100E Marie Mount Hall
College Park, Maryland 20742-7531,
USA
Modeling complex technical systems is highly desirable but very challenging. Many modeling techniques have been developed and used in scientific disciplines, such as Artificial Intelligence, Risk Assessment, Reliability Engineering and Cognitive Science. Each of these techniques are dedicated to a specific aspect of complex systems, and most utilize a structural/behavioral modeling approach to describe the system. For example, in risk assessment, fault tree and event tree models are used to model structural behavioral aspects of nuclear and complex chemical plants. The relatively new approach of Functional Modeling is becoming a leading modeling approach for complex physical plants.
The objective of this workshop series is to provide an opportunity to present and discuss various methods and experiences with the functional modeling of complex technical systems. The workshop brings together the world’s leading experts in the area of functional modeling from diverse fields (Artificial Intelligence, Risk and Reliability, Safety Critical Computing Systems, Control Engineering and Cognitive Science) to present and discuss:
IFMAA Organization, and
Center for Technology Risk
Studies
University of Maryland, College Park
Maryland 20742-7531, U.S.A.
Abstract: In this paper we start with a brief introduction to the Functional Representation framework that a number of colleagues and we have been developing for over a decade or so. Then we move on to the need for a precise language for describing objects, properties and causal relations. We argue that such a language is needed to express the meaning of terms such as “function” and “behavior.” We briefly describe a formal framework for definition of device function that we have recently developed. We have sought the smallest ontological framework that is sufficient for developing an idea of function. Functions are defined in terms of the effects of objects on their environments. The definition of function is sufficiently general to express static and dynamic functions, intended and natural functions, and functions of abstract and physical objects.
Abstract: A function-based lexicon for classifying the most common elements of engineering systems has been proposed. This classification is based on the conservation laws that govern the engineering systems. An example of developing a functional model based on this lexicon is provided. It has been shown that function descriptions based on conservation laws provide a simple and rich vocabulary for functional modeling of the complex engineering systems.
Abstract: Planning and describing changes in the operating mode of a
complex system, such as a power plant or chemical installation, is very
complicated. Often plans for such a transition are hardly flexible, and
depend on a well-defined initial mode for the plant for their successful
completion. This paper proposes an alternative method for developing and
describing intentional mode transitions, using Multilevel Flow Modeling
(MFM).
A mode transition is initiated by considering the goals that must be
achieved in the new mode. A set of rules is proposed that describe how
the new goals are added to the goals that were achieved before the change
was initiated and the conditions under which the old goals become irrelevant.
On the basis of reasoning about the causal relations between the functions
and the goals in the MFM model, the actions to complete a transition to
the new mode can be derived.
The advantage of this description of change over a fixed plan or procedure
is that it is independent of the actual state of the process before the
change is initiated. Possible applications are automation of mode changes,
improvement of alerting systems for the operator or providing knowledge
based support.
The rules for inferring the states of goals and functions, and for
determining the required actions to effectuate a change will be illustrated
at the hand of a very simple example system.
Abstract: This paper presents the FDef (Functional Diagnosis with efforts and flows) approach to model-based diagnosis. First, it motivates the research by considering the field of functional flow-based diagnostic techniques, pointing out some of their relevant limitations, which are overcome by FDef. Then, it summarizes and exemplifies the main FDef concepts and techniques. The proposed ideas can be easily adapted to other flow-based modeling formalisms, such as MFM (Multilevel Flow Modeling). The final part of the paper outlines the most recent developments of FDef.
Abstract: In this paper, the features of the Goal Tree-Success Tree (GTST), Multilevel Flow Modeling (MFM), and Hybrid MFM-GTST methods from a viewpoint of Function-Oriented System Analysis (FOSA) have been discussed. Based on the discussion, a comparison of these methods has taken place.
Abstract: The work of development of a new generation interface has been carried out at the LAMIH (Laboratoire d’Automatique et de Mécanique Humaines) of the University of Valenciennes. Thanks to the use of complementary functional analysis techniques, the LAMIH has designed the supervisory interfaces of an existing process by integrating an original alarm filtering system based on fuzzy reasoning.
Abstract: This paper describes the results of preliminary study to develop a meaning display interface system (MDIS) to support plant operators in which plant designer’s intentions are efficiently used to indicate plant conditions and alternative counter actions in an emergency situation. A plant is modeled by a behavioral-MFM model which is an extension of a functional modeling framework MFM (Multilevel Flow Modeling) to express not only designers’ intentions but also the behaviors of plant components, quantitative relations between goal and functions, and available plant operations. A technique is proposed to find possible counter actions by applying qualitative reasoning technique to a behavioral-MFM model. The inference processes of the MDIS to estimate the influence of an anomaly and to find counter actions are discussed by an anomalous condition of an example engineering system.
Abstract: A method has been developed for organizing and using heuristic, deterministic and probabilistic knowledge in a manner useful for making inferences to support decisionmaking. The method involves the hierarchical breakdown of the desired objective in order to identify significant events impacting the capability to meet the objective, sequential ordering of the significant events, identification of the conditions which impact the events, and ranking of alternative means for altering the possibility of the occurrence of the significant events. An application of this method is discussed. The application is a model of severe accident phenomena at a nuclear power plant useful in supporting the prioritization of strategies to mitigate a severe accident.
Abstract: This paper describes a representation for modeling the structure and behavior of computer controlled process plants. A simple and clear representation is necessary in the process industry for engineers to carry out hazard identification studies. A suitable model will provide engineers, from different disciplines, a basic understanding of the process plant under consideration and facilitate discussion and the hazard identification process. The proposed representation, Process Control Event Diagram (PCED), is an extension of ETD (Event Time Diagram) and complements the P&ID (Piping and Instrumentation Diagram) commonly used in the process industry. The use of PCED is illustrated using different control system configurations.
Abstract: In the framework of the International Electrotechnical Committee (IEC) 65 C, the working group 7 “process control function blocks” is currently working on the definition of a standard for function blocks. This IEC standard should allow companies to specify control applications whatever the type of Instrumentation & Control (I&C) device is compliant with the standard. The method presented in this paper is focusing on the control processing. We intend to uncouple the control functions and the control documents, because methods are different. We will not present the control document as operator interface. The I&C life cycle for the control functions should be defined in three steps:
Abstract: The on-board diagnostic facilities of an unmanned vehicle for submarine inspection of pipes and cables are described. There is a local diagnostic mechanism for each module in the control hierarchy overlooking the levels below itself. In case of ambiguities and conflicts a global diagnosis system will be interrogated. The global diagnosis mechanism applies a general GTST functional diagram for the missions to be carried out by the vehicle. The mission plan is written in a specially constructed macro language downloaded to the vehicle computer network before each new launch. Each command of this language will correspond to a well defined set of the functions available in the GTST diagram. When a diagnosis of an execution failure for one of the mission language commands must be handled, the reasoning in a diagnosis knowledge base can follow the hierarchy of the GTST diagram.
Abstract: In a multidisciplinary design environment, such as Architecture-Engineering-Construction (AEC) domain, the various designers will have their own concepts and representations of the design object making communication in such an environment a complex task. Computer-aided design (CAD) modeling is seen as the vehicle for interdisciplinary communication and integration. However, this paper stresses the need for a multiple view approach based upon an assumption that different views of an object are based on different functional contexts. The paper demonstrates that an understanding of concepts such as function, purpose and intent is critical since the representation of the functional properties of design objects is the underlying basis for the formation of different representations and the coordination of these representations. Thus the explicit representation of function and purpose are essential, in a CAD environment, for the necessary communication of intent and effects.
Abstract: The RELIASEP(R) method and its support tool have been used to carry out the functional analysis of large systems within the framework of the design of new power plants. The principles of the method are based on the breakdown of functions into tree(s). These functions are characterised by their performance and constraints. In this paper we will present the main modifications made under Electricité de France (EdF) requirement, and in particular the “viewpoints” analyses. The paper finishes with the knowledge obtained from the same studies that were carried out.
Abstract: The technical control of an industrial process depends on its functional and dysfunctional behavior. Therefore, it is important to control functions such as reliability, availability and maintainability, an approach often used for electrical and electronic systems. Mechanical systems offer a wider range of variability and are the subject of this paper. The relationship between an “elementary function” and an “elementary component” is viewed from a kinematic point of view, which is structured and hierarchic, thus allowing a global view of the system in its environment. The objective of the model discussed in the paper is the simulation and control of the system from functional and dysfunctional points of view.
Abstract: This paper presents the process of elaboration and modeling as applied to a nuclear plant. It is a systemic process named “SAGACE.” The resulting model represents a complex integrated system offering nine viewpoints and allows the separate designers of a power plant to work with the same single model.
Abstract: Task allocation between man and machine is an important factor regarding safety, reliability and efficiency of industrial processes. One should allocate tasks in order to maximize the operator’s situation understanding and ability to handle unexpected events. Functional models can be used to study function allocation in a process control environment, because they explicitly describe functions and tasks of both the plant and the operator. The Halden Reactor Project is currently engaged in such a project, aimed specifically at the work in a nuclear power plant control room. This paper describes the main features of the approach, and discusses how functional modeling can be used to address the issue of how much information is necessary for the operator, and thereby give a basis for how tasks should be allocated.
Abstract: This paper describes the application of functional modeling to the task analysis of airline pilots in glass cockpit using Structure & Functions (S&F). S&F is a process functional modeling method and an intelligent event analysis and decision support system. For Airbus Industrie, it has been applied in the analysis of pilot crew task observations and is currently used to build a computer dynamic model of the crew-aircraft interaction. This model enables to go further in the usability engineering of aircraft operating procedures and crew training and in the development of new intelligent training aids.
Abstract: Modeling of user tasks in complex applications allows a richer
interaction between the user and the system. Thanks to that, systems are
able to more precisely determine the user objectives, but at the same time,
system modeling becomes very complex and difficult to deal with. In this
paper we introduce an Advanced Task-Oriented Management System, ATOMS,
that makes use of parsing techniques for user-task recognition. These techniques
are proven to be very powerful, making the management of complex tasks,
like the ones present in current interactive applications, easier.
Abstract: In this paper the TROPOS functional model is applied to a maintenance problem in an industrial setting. This model has also been widely used in other fields like software engineering, banking and postal systems. It integrates a referenced vocabulary and a specific language relying on qualitative and quantitative tools. The first half of this paper presents information about the TROPOS method, and the second half describes an application to a maintenance system for a nuclear plant in France.
Abstract: The subject is about the formulation of a firm processes,
in order to answer the following question “Cost of goods is appropriate
with the price of these goods?” The formulation concerns the functions
of the firm’s processes. The method explained is called TROPOS. Any process
is decomposed into three components, working view, feedback view, communication
view. Each component will be described by objects named, “products” for
the working view, “procedures” for the feedback view, “actors” for the
communication view. A language is used to describe the different possible
states of processes; a state of a process is represented by the states
of its object. The calculation, according to Shannon’s formula, applied
to the script of states gives utility (i.e., price), and complexity (i.e.,
cost) of goods delivered during a cycle of process.
