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Gestalt psychologists promulgated the principles of visual organisation in the early twentieth century. These principles have been discussed and re-emphasised, and their importance and relevance to user interface design is understood. However, a limited number of systems represent and make adequate use of this knowledge in the form of a design tool that supports certain aspects of the user interface...
The lack of formal semantics for the UML creates many ambiguity problems, especially when real-time systems are specified. The paper proposes an approach to a formal definition of UML statecharts. Main features of the UML statecharts are described, and next, a transformation of the UML statecharts into LOTOS is defined.
We study a mathematical problem modelling the antiplane shear deformation of a viscoelastic body in frictional contact with a rigid foundation. The contact is bilateral and is modelled with a slip-dependent friction law. We present the classical formulation for the antiplane problem and write the corresponding variational formulation. Then we establish the existence of a unique weak solution to the...
The process of modelling and developing commonality and variability for system families should be supported by suitable methods and notations. The object-oriented methods and their notations, which are used at present, focus on the development of a single system at a time. In this paper we analyse feature models as a representation of the common parts and variants contained in a system family, and...
The paper presents a short overview of the foundations of the Role-Based Access Control Modal Model and its properties. In particular, the translation of these model formulae to the first-order logic formulae in a form of Horn's clauses is analysed. The automation of processes and mechanisms related to access control on the basis of logical automated reasoning and the PROLOG language are described.
The problem of modelling the dynamics of confidence levels between two individuals is investigated. A model, based on a master equation approach, is developed and presented. An important feature of the model is that self-confidence is modelled along with its interaction with confidence towards others. Simulation results are presented.
We consider linear 2-D systems of Fornasini-Marchesini type in the continuous-time case with non-constant coefficients. Using an explicit representation of the solutions by utilizing the Riemann-kernel of the equation under consideration, we obtain controllability and observability criteria in the case of the inhomogeneous equation, where control is obtained by choosing the inhomogeneity appropriately,...
The problem of zeroing the output in an arbitrary linear continuous-time system S(A,B,C,D) with a nonvanishing transfer function is discussed and necessary conditions for output-zeroing inputs are formulated. All possible real-valued inputs and real initial conditions which produce the identically zero system response are characterized. Strictly proper and proper systems are discussed separately.
With reference to the work of Verriest and Lewis (1991) on continuous finite-dimensional systems, the linear quadratic minimum-time problem is considered for discrete distributed systems and discrete distributed time delay systems. We treat the problem in two variants, with fixed and free end points. We consider a cost functional J which includes time, energy and precision terms, and then we investigate...
The problem of a linguistic description of dependencies in data by a set of rules Rk: "If X is Tk then Y is Sk" is considered, where Tk's are linguistic terms like SMALL, BETWEEN 5 AND 7 describing some fuzzy intervals Ak. Sk's are linguistic terms like DECREASING and QUICKLY INCREASING describing the slopes pk of linear functions yk=pkx +qk approximating data on Ak. The decision of this...
We present a framework of L-fuzzy modifiers for L being a complete lattice. They are used to model linguistic hedges that act on linguistic terms represented by L-fuzzy sets. In the modelling process the context is taken into account by means of L-fuzzy relations, endowing the L-fuzzy modifiers with a clear inherent semantics. To our knowledge, these L-fuzzy modifiers are the first ones proposed that...
A novel approach to designing stable fuzzy controllers with perception-based information using fuzzy-arithmetic-based Lyapunov synthesis in the frame of computing with words (CW) is presented. It is shown that a set of conventional fuzzy control rules can be derived from the perception-based information using the standard-fuzzy-arithmetic-based Lyapunov synthesis approach. On the other hand, a singleton...
Perceptions about function changes are represented by rules like "If X is SMALL then Y is QUICKLY INCREASING." The consequent part of a rule describes a granule of directions of the function change when X is increasing on the fuzzy interval given in the antecedent part of the rule. Each rule defines a granular differential and a rule base defines a granular derivative. A reconstruction of...
Applying the generalised extension principle within the area of Computing with Words typically leads to complex maximisation problems. If distributed quantities--such as, e.g., size distributions within human populations--are considered, density functions representing these distributions become involved. Very often the optimising density functions do not resemble those found in nature; for instance,...
A modification of Dempster's and Pawlak's constructs forms a new foundation for the identification of upper and lower sets formulas. Also, in this modified Dempster-Pawlak construct we require that subsets of the power set be restricted to the well-known information granules of the power set. An aggregation of upper information granules amongst each other and lower information granules amongst each...
A new learning method tolerant of imprecision is introduced and used in neuro-fuzzy modelling. The proposed method makes it possible to dispose of an intrinsic inconsistency of neuro-fuzzy modelling, where zero-tolerance learning is used to obtain a fuzzy model tolerant of imprecision. This new method can be called e-insensitive learning, where, in order to fit the fuzzy model to real data, the e-insensitive...
Computing, in its usual sense, is centered on manipulation of numbers and symbols. In contrast, computing with words, or CW for short, is a methodology in which the objects of computation are words and propositions drawn from a natural language, e.g., small, large, far, heavy, not very likely, the price of gas is low and declining, Berkeley is near San Francisco, it is very unlikely that there will...
Our thesis is that computing with words needs to account for the uncertainties associated with the meanings of words, and that these uncertainties require using type-2 fuzzy sets. Doing this leads to a proposed architecture for making judgments by means of computing with words, i.e., to a perceptual computer - the Per-C. The Per-C includes an encoder, a type-2 rule-based fuzzy logic system, and a...
The paper describes a spectral method for combinational logic synthesis using the Walsh transform and the Reed-Muller form. A new algorithm is presented that allows us to obtain the mixed polarity Reed-Muller expansion of Boolean functions. The most popular minimisation (sub-minimisation) criterion of the Reed-Muller form is obtained by the exhaustive search of all the polarity vectors. This paper...
Many approaches such as component technologies have been invented in order to support software reuse. Based on these technologies a large variety of techniques have been introduced to connect components. However, there is little experience concerning the validation of component systems. We know how to plug components together, but we do need ways to check whether that works. In this paper we introduce...
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