Showing papers presented at "Computer Aided Systems Theory in 1995"
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22 May 1995TL;DR: This paper proposes for cryptographic applications to use maps as state transition function of a discrete dynamical system which leads to deterministic chaos by making use of generalized versions of the well-known baker transform, which are discrete and finite.
Abstract: In the past there have been several attempts to apply the field of deterministic chaos to cryptography. In this paper we propose for cryptographic applications to use maps as state transition function of a discrete dynamical system which leads to deterministic chaos. More specifically, we make use of generalized versions of the well-known baker transform, which are discrete and finite. Since they relate by group-theoretic representation to Bernoulli-shifts, we call them BernouIli permutations. The iteration of Bernoulli permutations on a set of data realizes a repeated "stretching" and "compressing" which has been compared by the "rolling" and "folding" in the work of a baker by mixing a dough. The knowledge of the importance of such operations for cryptography goes back to the fundamental paper of Claude Shannon ([8]), a fact which has been pointed out earlier in a paper by N.J.A. Sloane ([9]). The results reported in this paper are based mainly on the PhD-thesis of the second author ([6]). A Technical Report of the first author formed the starting basis for it. This paper extends the results which have been reported in earlier papers ([10],[11]).
52 citations
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22 May 1995TL;DR: The concept and method of incursion and hyperincursion firstly applied to the Fractal Machine, an hyperincursive cellular automata with sequential computations where time plays a central role and the Pearl-Verhulst chaotic map will be considered.
Abstract: This paper will analyse the concept and method of incursion and hyperincursion firstly applied to the Fractal Machine, an hyperincursive cellular automata with sequential computations where time plays a central role. This computation is incursive, for inclusive recursion, in the sense that an automaton is computed at the future time t+1 in function of its neighbour automata at the present and/or past time steps but also at the future time t+1. The hyperincursion is an incursion when several values can be generated at each time step. The incursive systems may be transformed to recursive ones. But the incursive inputs, defined at the future time step, cannot always be transformed to recursive inputs. This is possible by self-reference. A self-reference Fractal Machine gives rise to A non deterministic hyperincursive field rises in a self-reference Fractal Machine. This can be related to the Final Cause of Aristotle. Simulations will show the generation of fractal patterns from incursive equations with interference effects like holography. The incursion is also a tool to control systems. The Pearl-Verhulst chaotic map will be considered. Incursive stabilisation of the numerical instabilities of discrete linear and non-linear oscillators based on Lotka-Volterra equation systems will be simulated. Finally the incursive discrete diffusion equation is considered.
21 citations
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22 May 1995
TL;DR: It is shown that the exclusive OR can be modelled by a fractal non-linear equation and a new method to design digital equations is proposed to create McCulloch and Pitts formal neurons.
Abstract: The goal of CAST research and development is to provide modelling tools for formal systems design in the field of information and systems engineering. This paper deals with such modelling tools for formal systems related to Zuse, Deutsch and McCulloch and Pitts computing principles. The semantic logic of such systems can be exhibited in replacing the differential equations by digital cellular automata. K. Zuse proposed such a method for representing physical systems by a computing space. I show that the digital wave equation exhibits waves by digital particles with interference effects. The logical table of the wave equation shows the conservation of the parity related to exclusive OR. The Fractal Machine proposed by the author deals with a cellular automata based on incursion, an inclusive recursion, with exclusive OR. In this machine, the superimposition of states is related to the Deutsch quantum computer. Finally, it is shown that the exclusive OR can be modelled by a fractal non-linear equation and a new method to design digital equations is proposed to create McCulloch and Pitts formal neurons.
15 citations
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22 May 1995
TL;DR: One modelling technique which considers the behaviour of all the different system elements is elaborated within this paper, which shows how differential equations as used for the description of the physical elements can be modelled by this technique.
Abstract: Current systems are no longer pure physical systems or information systems but tend to consist of elements from both of these areas Thus, one modelling technique which considers the behaviour of all the different system elements is elaborated within this paper Extended Predicate/Transition nets often used for information technology serve as a basis for this modelling It is shown how differential equations as used for the description of the physical elements can be modelled by this technique Linear and nonlinear systems are regarded as well as the coupling of these systems For continuous modelling of the equations a continuous Predicate/Transition net is presented
12 citations
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22 May 1995TL;DR: The resulting design and simulation environment will allow the designer to make multiple iterations between functional and performance validation, and therefore the quality of the system design will be improved and the risk not to meet e.g. the performance requirements will be reduced dramatically.
Abstract: Up to now no tool is available on the market that allows functional design and performance analysis within the same environment. Mostly new models have to be built to do performance analysis. This approach is time consuming and erroneous. To overcome this awkward situation two tools, namely GEODE/SDL a typical design tool and SES/workbench a typical simulation tool were coupled. The resulting design and simulation environment will allow the designer to make multiple iterations between functional and performance validation, and therefore the quality of the system design will be improved. Additionally the risk not to meet e.g. some of the performance requirements will be reduced dramatically.
10 citations
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22 May 1995TL;DR: Basic properties of categorical shape theory are introduced in order to better understand system approximation and construction.
Abstract: Categorical modelling is a useful tool in the study of systems. The basic idea of categorical shape theory is that, in any approximating situation, the approximations are what encode the only information that the system can analyse. Such approximations are very important in using time-varying complex systems to model system developments. Within this context, basic properties of categorical shape theory are introduced in order to better understand system approximation and construction.
8 citations
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22 May 1995TL;DR: A symbolic computing tool is introduced, denoted by NLPID in the sequel, for the automatic design of linear and nonlinear PID controllers for nth order nonlinear control systems.
Abstract: In this paper we introduce a symbolic computing tool, denoted by NLPID in the sequel, for the automatic design of linear and nonlinear PID controllers for nth order nonlinear control systems. The nonlinear design algorithm is based upon Rugh's Extended Linearization Technique, and it was implemented using Mathematica® as symbolic computing platform. At its present stage of development NLPID uses Ziegler-Nichols tables to synthesize linear PID controllers, and therefore its ability to deal with first and second order plants could be limited.
7 citations
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22 May 1995
TL;DR: A crucial aspect in this attempt to make the logic link between the application domain specific view and the formal view explicit is the concept of evolving algebra, which provides the formal basis of a specification methodology which has been applied to a variety of specification and verification problems.
Abstract: As part of a comprehensive design concept for complex reactive systems we investigate the derivation of formal requirements and design specifications at systems level. We discuss the meaning of correctness with respect to the embedding of mathematical models into the physical world. A crucial aspect in our attempt to make the logic link between the application domain specific view and the formal view explicit is the concept of evolving algebra [13, 14]; it provides the formal basis of a specification methodology which has successfully been applied to a variety of specification and verification problems. We introduce an evolving algebra abstract machine as a conceptual framework for the development of tools for machine based analysis and execution of evolving algebra specifications.
7 citations
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22 May 1995TL;DR: ECBS (Engineering of Computer Based Systems) provides frameworks of architecture principles to model perceived environments in which CBS must be embedded and the functionality of CBS as discrete event systems and to model physical CBS as service-oriented systems.
Abstract: ECBS (Engineering of Computer Based Systems) provides frameworks of architecture principles to model perceived environments in which CBS (Computer Based Systems) must be embedded and the functionality of CBS as discrete event systems and to model physical CBS as service-oriented systems. In addition it contains frameworks for process models with precise guidelines to perform all engineering steps required to build these models and to integrate and operate CBS as well as frameworks for information models with precise guidelines what information has to be captured within an ECBS process to establish the documentation for a complete and consistent information base.
7 citations
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22 May 1995TL;DR: The main objective of this paper is to present a language which allows the description of software systems in an evolutive way, based on a model of software system which incorporatesevolutive features in its structure and functioning.
Abstract: Software systems are conceived by the developers in an iterative, recursive and evolutive way. Traditional software development methods avoid the modelling of this evolutive conception. Three years ago we began the development of a method (MEDES) which tries to model and represent this important characteristic of all the human conception activities. The main objective of this paper is to present a language which allows the description of software systems in an evolutive way, based on a model of software system which incorporates evolutive features in its structure and functioning. The language is used to make prototypes of software systems in a tool (HEDES) which implements the method.
7 citations
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22 May 1995TL;DR: The Generalized Magnitudes Scheme is extended by adding autonomous activation — the system determines the next instant in which it must be re-evaluated, which allows using the GeneralizedMagnitudes for representing and simulating Discrete Events models directly, which contributes several interesting representational properties.
Abstract: The relationship between Generalized Magnitudes (a Temporal Reasoning Scheme) and Discrete Event Systems Specifications is examined, revisiting a previous work of translation between both formalisms. As a result of this study, the Generalized Magnitudes Scheme is extended by adding autonomous activation — the system determines the next instant in which it must be re-evaluated. This new feature allows using the Generalized Magnitudes for representing and simulating Discrete Events models directly, which contributes several interesting representational properties. Finally, the computing process of the next activation instant is described.
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22 May 1995
TL;DR: An object-oriented method to represent knowledge about a set of digital systems so that concrete systems can be specified and their implementations in various models such as VHDL or Petrinets can be derived automatically from a specification by a knowledge based configuration system.
Abstract: We present an object-oriented method to represent knowledge about a set of digital systems. Based on this representation, concrete systems can easily be specified, their implementations in various models such as VHDL or Petrinets can be derived automatically from a specification by a knowledge based configuration system. In this paper, we focus on the set-theoretic foundations of our model.
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22 May 1995TL;DR: The training of Nuclear Power Plant Operators is the utmost importance for the proper running of Plants, with the strictest of security conditions.
Abstract: The training of Nuclear Power Plant Operators is the utmost importance for the proper running of Plants, with the strictest of security conditions. Given the specific characteristics of this type of energy, the training of operators can be carried out only by means of simulators.
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22 May 1995
TL;DR: The model that is defined, called Interpreted Sequential Machine, is based on the concept of Sequential machine and avoids the main limitation by separating the purely sequential part of the system from the data and the operations on the data.
Abstract: The complexity of systems requires that validation methods are set in the designing phase as well as during their use or maintenance. We propose a modelling approach of the system which allows us to bring into play some methods for the validation of temporal and functional properties. The model that we have defined, called Interpreted Sequential Machine, is based on the concept of Sequential Machine and avoids the main limitation (combinatorial explosion of the number of states when introducing any new data) by separating the purely sequential part of the system from the data and the operations on the data. The validation of the complex system thus modelled consists in:
expressing the behaviour of the system by a set of symbolic, logicotemporal formulAE,
carrying out automatic proof procedures on these formulAE.
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22 May 1995
TL;DR: This paper deals with the systematical checking of the possible equality of two functions or what is the same, of two expressions, and a procedure to determine the Canonical Expression.
Abstract: This paper deals with the systematical checking of the possible equality of two functions or what is the same, of two expressions. The nature of the problem is first considered. The concept of Universe is reexamined. The concepts of Object Attribute Power Table, Prime Universe, Prime Table and Canonical Expression, unique for each class of equivalent functions, are introduced. A procedure to determine the Canonical Expression is presented.
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22 May 1995TL;DR: It is claimed that, within the proposed framework, a class of mappings stands for refinement, and it is proved that refinement satisfies the diagonal compositionality requirement, i.e., refinements compose and distribute over system composition.
Abstract: A categorial semantic domain for general (discrete event) systems based on labeled transition systems with full concurrency is constructed, where synchronization and hiding are functorial. Moreover, we claim that, within the proposed framework, a class of mappings stands for refinement. Then we prove that refinement satisfies the diagonal compositionality requirement, i.e., refinements compose (vertical) and distribute over system composition (horizontal).
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22 May 1995TL;DR: A general, uniform and concise mathematical framework for modelling of systems, especially discrete systems, as basic structures families and relations, defined as families of families represented in parameterized form are used, which allows the representation of dual and polymorphic relations.
Abstract: The intention of this article is to present a general, uniform and concise mathematical framework for modelling of systems, especially discrete systems. As basic structures families and relations, defined as families of families represented in parameterized form, are used, which allows the representation of dual and polymorphic relations. On these structures structors are applied to obtain higher level structures, parts of these, and lower level structures from higher level structures. Considered are the π-product, selection of sub structures by properties, concatenations of relations subject to constraints. Treated are structures on index sets, topological structures, valuated structures, in particular fuzzy sets, sets of times as complete atomic boolean lattices with ordered atoms and induced orderings on the times, coarsenings of a time set, processes and their interactions, refinement and coarsenings of processes, and variables with their assignment operators. Most of our definitions are more general than those in literature. Relationships between various systems in applications are pointed out and illustrated by examples.
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22 May 1995TL;DR: With the development of new computing paradigms, such as neural networks and genetic algorithms, new tools have become available in computer-aided systems theory that can be used to tackle problems that are considered “hard” in traditional systems theory, like the modeling and identification of nonlinear dynamical systems.
Abstract: With the development of new computing paradigms, such as neural networks and genetic algorithms, new tools have become available in computer-aided systems theory. These tools can be used to tackle problems that are considered “hard” in traditional systems theory, like the modeling and identification of nonlinear dynamical systems.
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22 May 1995TL;DR: The trigger graph methodology is introduced, which uses a notation that is similar to timing diagrams, but it strictly avoids their disadvantage of being ambiguous, and gives the possibility to transform it into Petri nets.
Abstract: The formal description of hardware protocols allows system engineers to check these protocols for some important properties, such as completeness and consistency. In this paper, a methodology called trigger graph is introduced. It uses a notation that is similar to timing diagrams, but it strictly avoids their disadvantage of being ambiguous. In addition, the exact mathematical notation of the trigger graph gives the possibility to transform it into Petri nets. This gives the benefit to use methods developed for Petri nets also for the check of hardware protocols, for example to check them for security conditions. The trigger graph methodology is illustrated with three realistic examples: the control of traffic lights, the control of a railway-barrier, and the read-protocol for a DRAM.
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22 May 1995TL;DR: A task management system (TMS) should take care of all aspects of a task construction and its operation.
Abstract: A task which is supposed for our DSS (actDSS) consists of integrated models, solvers, graphical models for imput and output, various data models connected a data base and others. The organization of these subsystems is a task. A task management system (TMS) should take care of all aspects of a task construction and its operation. In this paper the concept of TMS is proposed and the structure and function are discussed.
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22 May 1995TL;DR: Concepts and techniques evolved in systems theory based modeling and simulation research are discussed to provide a methodology for large scale transport system analysis and design.
Abstract: Multimodal transport, i.e. transport which is accomplished by different transport means like truck and train, is a most important issue of the European transport policy. It offers a viable and efficient alternative to long distance road transport. However, due to its much more complex organizational needs compared to pure road transport, multimodal transport systems have to be designed with utmost care and its operation has to be well coordinated and managed. In this paper we discuss concepts and techniques evolved in systems theory based modeling and simulation research to provide a methodology for large scale transport system analysis and design. The methodology gains its power by integrating several distinct approaches, viz. multilevel, hierarchical modeling as developed by Mesarovic, multifacetted object oriented modeling as defined by Zeigler, and multiformalism, modular hierarchical systems theory based modeling formalisms.
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22 May 1995TL;DR: An elementary symbolic method for the estimation of basins of attraction in second order nonlinear dynamical systems is formulated and its implementation using Mathematica® is shown.
Abstract: In the present paper an elementary symbolic method for the estimation of basins of attraction in second order nonlinear dynamical systems is formulated and its implementation using Mathematica® is shown. The estimation algorithm is based upon the construction of positively invariant compact boxes that trap the trajectories with unbounded initial conditions. We obtain such boxes through a Lyapunov function whose orbital derivative is bounded by a bounding function that can be represented as the addition of two scalar functions. The detection of persistent oscillating behaviors deserves a prominent place between all possible applications of our tool, as it will be shown by considering Fitzhugh Equations as a case study.
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22 May 1995TL;DR: The conclusion is that the use of the same paradigm is valid, that considerable difference have to be considered in its implementation.
Abstract: This paper discusses similarities of computer support in three areas: development of software, supporting the flow of work/documents in an office and the production of goods in a flexible work cell. All three areas obey the same underlying principle, i.e. defining a process and then interpreting the process by an enactment (interpretation) mechanism. In the paper elementary questions with respect to the similarity are raised and tentative answers given. The conclusion is that the use of the same paradigm is valid, that considerable difference have to be considered in its implementation.
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22 May 1995TL;DR: It is shown that a solution to the multiple planning problem can be written in procedural (imperative) languages like Pascal and it is proven that a multiple plan can be generated by a conditional-iterative action.
Abstract: This paper deals with a multiple planning problem, which is a collection of planning problems defined for the same partial transition system and have the same set of goal states. It is shown that a solution to the multiple planning problem can be written in procedural (imperative) languages like Pascal. The formal definition of the syntax and semantics of conditional-iterative actions is provided. It is proven that a multiple plan can be generated by a conditional-iterative action. A language of formal representation of partial transition systems with a vector-state space is proposed.
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22 May 1995TL;DR: This work presents a study on a method for automatically inducing a discrete event structure (DEVS) from descriptions of behaviours of a system using inductive learning and DEVS formalisms.
Abstract: Machine Learning methods seem to help for model-building in the field of Systems Theory. In this work, we present a study on a method for automatically inducing a discrete event structure (DEVS) from descriptions of behaviours of a system. To this end, both inductive learning and DEVS formalisms have been made compatible in order to translate input data into a form usable by the inductor. Morover, the language used in classical inductive learning algorithms must be enhanced to cope with the temporal characteristics of input data.
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22 May 1995TL;DR: In this article, a universal state space representation of a general discrete event system with past-determinacy, stationarity, the discrete event input space, and discrete event-deterministic mechanism is presented.
Abstract: Many man-made systems have discrete event mechanism. This paper first shows briefly a way how to construct a universal state space representations of a general discrete event system that is an input-output system with past-determinacy, stationarity, the discrete event input space, and discrete event-determinacy. The constructed state space representation for a discrete event system is minimal in a class of dynamical system representations of the system. This realization theory provides the fact that a reduced and reachable DEVS, which is originated by Zeigler[1], is unique up to isomorphism in the class of discrete event dynamical system representations. In this sense DEVS has concise information to describe discrete event dynamics. Since the Petri net formalism, that is a bit different from the DEVS formalism, is also used for the design and analysis of discrete event systems, some relation between DEVS and Petri nets is considered.
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22 May 1995TL;DR: A new concept in systems theory, the intersensorial transformations (IT), is introduced that is transparent and general enough to include sensory-motor transformations for robotic actions.
Abstract: This paper has a theoretic nature. We introduce a new concept in systems theory, the intersensorial transformations (IT). This concept is transparent and general enough to include sensory-motor transformations for robotic actions.
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22 May 1995
TL;DR: The main motivation of this work was to find an answer to the question: Given an AGVs network, a computational power and a criteria of evaluation of the performance, which are the scheduling heuristic and the length of the list of tasks that give the best performance?
Abstract: In this paper it is tried to present the methodology of design, implementation, experimentation and validation used in the development of an autonomous guided vehicle (AGV) network simulator This work arises in the context of the design of AGVs networks The optimal solution of the problems associated to the management of an AGVs network is very heavy computationally In common practice are used heuristics that don't guarantee the optimal solution The main motivation of this work was to find an answer to the question: Given an AGVs network, a computational power and a criteria of evaluation of the performance, which are the scheduling heuristic and the length of the list of tasks that give the best performance?
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22 May 1995TL;DR: A theorem is developped which allows the Systematic generation of Complete Transform in the above case.
Abstract: 1)
We have studied in depth the Theory of Receptive Field Functinal Transformation, increasing their scope to situations of variable dimension partitions.
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We have developped a theorem which allows the Systematic generation of Complete Transform in the above case.
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22 May 1995TL;DR: The prototype of an architecture for a design process management system (DPMS) is presented, which promotes highly autonomous execution of system designs and is also applicable to other design domains.
Abstract: This paper discusses concepts and techniques supporting modelling, planning and execution of design activities in distributed design environments The task of planning, executing, and supervising the design processes has become so complex that it itself requires advanced computer support facilities We propose extended planning facilities exploiting old design projects The planning functions form a basis for a larger framework for decision and execution support In what follows, we discuss the phases of a design process, especially planning including process model generation using history based planning techniques Finally, we present our prototype of an architecture for a design process management system (DPMS) The DPMS architecture promotes highly autonomous execution of system designs The system has been used in the electronic design automation area The concepts described here, however, are also applicable to other design domains