Showing papers in "Fuzzy Sets and Systems in 2007"

TL;DR: The result provides a set of progressively less conservative sufficient conditions for proving positivity of fuzzy summations of Polya's theorems on positive forms on the standard simplex.

TL;DR: The fundamental concepts of cluster validity are introduced, and a review of fuzzy cluster validity indices available in the literature are presented, and extensive comparisons of the mentioned indices are conducted in conjunction with the Fuzzy C-Means clustering algorithm.

TL;DR: A method for multi-attribute decision making problems with linguistic information, in which the preference values take the form of linguistic variables, and a procedure to group multiple attribute decision making is provided under linguistic environment.

TL;DR: Two fuzzy portfolio selection models where the objective is to minimize the downside risk constrained by a given expected return are presented where the rates of returns on securities are approximated as LR-fuzzy numbers of the same shape.

TL;DR: A direct adaptive fuzzy control scheme for a class of uncertain continuous-time single-input single-output (SISO) nonaffine nonlinear dynamic systems and it is shown that the tracking error converges to a neighborhood of zero.

TL;DR: New lower and upper approximations are proposed and some important properties in generalized rough set induced by a covering are obtained and compared with ones of Pawlak's rough sets and Bonikowski's covering generalized rough sets.

TL;DR: This work establishes the dual problem of the linear programming problem with trapezoidal fuzzy variables and deduces some duality results, and proves that the auxiliary problem is indeed the dual of the FVLP problem.

TL;DR: This paper addresses robust H"~ fuzzy static output feedback control problem for T-S fuzzy systems with time-varying norm-bounded uncertainties with three drawbacks existing in the previous papers eliminated.

TL;DR: An algorithm for obtaining the best threshold of a grayscale image with a single object and two algorithms for obtaining a sequence of optimal thresholds in images with several objects are presented.

TL;DR: This paper focuses on the problem of robust control for Takagi-Sugeno (T-S) fuzzy systems with time-delay and proposes new and less conservative delay-dependent stability conditions in terms of linear matrix inequalities (LMI).

TL;DR: It is postulate that introducing this graph allows a natural explanation of the different visions underlying Atanassov's model and interval valued fuzzy sets, despite both models have been proven equivalent when such a structure in the valuation space is not assumed.

TL;DR: A novel direct adaptive fuzzy tracking control scheme is presented for a class of perturbed strict-feedback nonlinear systems with unknown virtual control coefficients based on the Mamdani-type fuzzy logic system online approximation capability.

TL;DR: It has been shown that the H"~ filtering problem can be solved as a linear matrix inequality (LMI) optimization problem and sufficient conditions for the solvability of this problem are obtained using basis-dependent Lyapunov functions.

TL;DR: A new two-step fuzzy filter that adopts a fuzzy logic approach for the enhancement of images corrupted with impulse noise is presented and it is found experimentally that the proposed method provides a significant improvement on other state-of-the-art methods.

TL;DR: Some results on fuzzy contractive mappings in [V. Gregori, A. Sapena, On fixed point theorems in fuzzy metric spaces, Fuzzy Sets and Systems 125 (2002) 245-253] are extended to Edelstein fuzzy contractively mappings by modifying the notion of convergence in fuzzy metrics spaces.

TL;DR: A new fuzzy mathematical programming model for production planning under uncertainty in an industrial environment that considers fuzzy constraints related to the total costs, the market demand and the available capacity and fuzzy coefficients for the costs due to the backlog of demand and for the required capacity.

TL;DR: A basic question in fuzzy set theory: what is a many valued topology on a set X?

TL;DR: A system for assessing the risk of natural disasters, particularly under highly uncertain conditions, i.e. where neither the statistical data nor the physical knowledge required for a purely probabilistic risk analysis are sufficient.

TL;DR: Fuzzy number approximation by trapezoidal fuzzy numbers which preserve expected interval is discussed and the previously proposed approximation operator is improved so as to always produce a well formed trapezoid fuzzy number.

TL;DR: An iterative algorithm for multiple regression with fuzzy variables is proposed using the standard least-squares criterion as a performance index and the regression problem is posed as a gradient-descent optimisation.

TL;DR: The entropy-subsethood and interval-valued fuzzy entropy theorems are stated and algebraically proved, and a relation with the cardinality of fuzzy sets (FSs) is also demonstrated.

TL;DR: This paper shows that some assumptions are needless and presents two characterizations of S-implications with mutually independent requirements and also presents characterization of (S,N)-implications obtained from continuous fuzzy negations or strict negations.

TL;DR: A direct adaptive fuzzy almost disturbance decoupling control scheme is proposed based on the backstepping technique, which guarantees internal uniform ultimate boundedness of the closed-loop adaptive systems and render a bounded approximate L"2 gain from the disturbance input to the output.

TL;DR: It is shown that the proposed classifier generalizes the conventional and fuzzy KNN algorithms and can distinguish between equal evidence and ignorance, and thus the semantics of the class confidence values becomes richer.

TL;DR: The results indicate that FR is useful to derive operating rules for a long-term planning model, where imperfect and partial information is available, and ANFIS is beneficial in medium-term implicit stochastic optimization as it is able to extract important features of the system from the generated input-output set and represent those features as general operating rules.

TL;DR: An iterative algorithm that assumes a generic ranking index for comparing the fuzzy numbers involved in the problem, in such a way that each time in which the decision-maker wants to solve a concrete problem, he can choose (or propose) the ranking index that best suits that problem.

TL;DR: This paper proposes a classifier based on fuzzy if-then rules that allows the incorporation of weighted training patterns which can be used to adjust the sensitivity of the classification with respect to certain classes.

TL;DR: A sufficient condition ensuring a discrete singular fuzzy system to be regular, causal and stable is proposed in terms of a set of linear matrix inequalities, and a robust stability condition is obtained.

TL;DR: This paper considers robust stability and stabilization of uncertain Takagi-Sugeno fuzzy time-delay systems where uncertainties come into the state and input matrices, and obtains delay-dependent sufficient conditions for the closed-loop system to be robustly stable.

TL;DR: Stability and stabilization conditions are first proposed, which are delay-dependent for state delay and delay-independent for input delay, and the guaranteed cost problem is addressed.