Aggregation operators based on indistinguishability operators

This article gives a new approach to aggregating assuming that there is an indistinguishability operator or similarity defined on the universe of discourse. The very simple idea is that when we want to aggregate two values a and b we are looking for a value λ that is as similar to a as to b or, in a more logical language, the degrees of equivalence of λ with a and b must coincide. Interesting aggregation operators on the unit interval are obtained from natural indistinguishability operators associated to t‐norms that are ordinal sums. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 857–873, 2006.     

Integration on finite sets

Various types of integrals with respect to signed fuzzy measures on finite sets with cardinality n can be presented as corresponding rules for partitioning the integrand. The partition can be expressed as an n‐dimensional vector, whereas the signed fuzzy measure is also an n‐dimensional vector. Thus, the integration value is the inner product of these two vectors. Two pairs of extremes, the Lebesgue‐like integral versus the Choquet integral and the upper integral versus the lower integral, are discussed in detail. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1073–1092, 2006.     

Multicriteria decision-making using Archimedean aggregation operators in Pythagorean hesitant fuzzy environment

In multicriteria decision-making (MCDM), the existing aggregation operators are mostly based on algebraic t-conorm and t-norm. But, Archimedean t-conorms and t-norms are the generalized forms of t-conorms and t-norms which include algebraic, Einstein, Hamacher, Frank, and other types of t-conorms and t-norms. From that view point, in this paper the concepts of Archimedean t-conorm and t-norm are introduced to aggregate Pythagorean hesitant fuzzy information. Some new operational laws for Pythagorean hesitant fuzzy numbers based on Archimedean t-conorm and t-norm have been proposed. Using those operational laws, Archimedean t-conorm and t-norm-based Pythagorean hesitant fuzzy weighted averaging operator and weighted geometric operator are developed. Some of their desirable properties have also been investigated. Afterwards, these operators are applied to solve MCDM problems in Pythagorean hesitant fuzzy environment. The developed Archimedean aggregation operators are also applicable in Pythagorean fuzzy contexts also. To demonstrate the validity, practicality, and effectiveness of the proposed method, a practical problem is considered, solved, and compared with other existing method.     

Intelligent evolutionary design: A new approach to optimizing complex engineering systems and its application to designing heat exchangers

A new method for optimizing complex engineering designs is presented that is based on the Learnable Evolution Model (LEM), a recently developed form of non‐Darwinian evolutionary computation. Unlike conventional Darwinian‐type methods that execute an unguided evolutionary process, the proposed method, called LEMd, guides the evolutionary design process using a combination of two methods, one involving computational intelligence and the other involving encoded expert knowledge. Specifically, LEMd integrates two modes of operation, Learning Mode and Probing Mode. Learning Mode applies a machine learning program to create new designs through hypothesis generation and instantiation, whereas Probing Mode creates them by applying expert‐suggested design modification operators tailored to the specific design problem. The LEMd method has been used to implement two initial systems, ISHED1 and ISCOD1, specialized for the optimization of evaporators and condensers in cooling systems, respectively. The designs produced by these systems matched or exceeded in performance the best designs developed by human experts. These promising results and the generality of the presented method suggest that LEMd offers a powerful new tool for optimizing complex engineering systems. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1217–1248, 2006.     

Extending multicriteria decision making by mixing t‐norms and OWA operators

We consider the problem of multicriteria decision making. We indicate how the evaluation of an alternative involves a determination of the degree to which subsets of criteria are satisfied by the alternative. This calculation is based upon an anding of the satisfactions of the individual criteria in the subsets. We consider the possibility of using t‐norms other than the Min for the and operation. Using this generalization we develop an extension of the OWA operators, called the TOWA, which involves a mixing of the t‐norm with the OWA operator. We extend this generalization to other aggregation techniques, the Choquet and Sugeno integrals. We introduce the concept of the Power of a t‐norm to provide an ordering over the t‐norm operators. We look at Power of a number of families of t‐norm. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 453–474, 2005.     

Assert and negate revisited: Modal semantics for UML sequence diagrams

Live Sequence Charts (LSC) extend Message Sequence Charts (MSC), mainly by distinguishing possible from necessary behavior. They thus enable the specification of rich multi-modal scenario-based properties, such as mandatory, possible and forbidden scenarios. The sequence diagrams of UML 2.0 enrich those of previous versions of UML by two new operators, assert and negate, for specifying required and forbidden behaviors, which appear to have been inspired by LSC. The UML 2.0 semantics of sequence diagrams, however, being based on pairs of valid and invalid sets of traces, is inadequate, and prevents the new operators from being used effectively. We propose an extension of, and a different semantics for this UML language—Modal Sequence Diagrams (MSD)—based on the universal/existential modal semantics of LSC. In particular, in MSD assert and negate are really modalities, not operators. We define MSD as a UML 2.0 profile, thus paving the way to apply formal verification, synthesis, and scenario-based execution techniques from LSC to the mainstream UML standard. Preliminary version appeared in SCESM '06: Proc. of the 2006 Int. workshop on Scenarios and State Machines, Shanghai, China (May 2006) [15]. This research was supported by the Israel Science Foundation (grant No.287/02-1), and by The John von Neumann Minerva Center for the Development of Reactive Systems at the Weizmann Institute of Science.     

On contra‐symmetry and MPT conditionality in fuzzy logic

This article deals with the N‐contrapositive symmetry of fuzzy implication operators J verifying either Modus Ponens or Modus Tollens inequalities, in a similar and complementary framework to the one in which Fodor (“Contrapositive symmetry of fuzzy implications.” Fuzzy Set Syst 1995;69:141–156) did begin with the subject in fuzzy logic, that is, with the verification of J(a, b) = J(N(b), N(a)) for all a, b in [0,1] and some strong‐negation function N. This property corresponds to the classical p → q = ¬q → ¬p. The aim of this article is to study that property in relation to either Modus Ponens or Modus Tollens meta‐rules of inference when the functions J are taken among those that belong to the usual families of implications in fuzzy logic. That is, the contra‐positive of S implications, R implications, Q implications, and Mamdani–Larsen operators, verifying either Modus Ponens or Modus Tollens inequalities or both, the conditionality's aspect on which lies the complementarity with Fodor. Within this study new types of implication functions are introduced and analyzed. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 313–326, 2005.     

Neural network modeling of microwave FETs based on third‐order distortion characterization

A new method for characterization of HEMT distortion parameters, which extracts the coefficents of a Taylor series expansion of I_ds(V_gs, V_ds), including all cross‐terms, is developed from low‐frequency harmonic measurements. The extracted parameters will be used either in a Volterra series model around a fixed bias point for 3^rd‐order characterization of small‐signal I_ds nonlinearity, or in a large‐signal model of I_ds characteristic, where its partial derivatives are locally characterized up to the 3^rd order in the whole bias region, using a novel neural‐network representation. The two models are verified by one‐tone and two‐tone intermodulation distortion (IMD) tests on a PHEMT device. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

On the use of adaptive rational interpolation for the calculation of resonator characteristics from EM analysis

Interpolation models are used in computational electromagnetic (CEM) analysis techniques to provide highly accurate models for microwave devices. In this article the use of a Thiele‐type adaptive rational interpolation formulation is exploited to accurately predict the natural frequencies and Q‐factors of a microstrip ring resonator. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

A majority model in group decision making using QMA–OWA operators

Group decision‐making problems are situations where a number of experts work in a decision process to obtain a final value that is representative of the global opinion. One of the main problems in this context is to design aggregation operators that take into account the individual opinions of the decision makers. One of the most important operators used for synthesizing the individual opinions in a representative value of majority in the OWA operator, where the majority concept used aggregation processes, is modeled using fuzzy logic and linguistic quantifiers. In this work the semantic of majority used in OWA operators is analyzed, and it is shown how its application in group decision‐making problems does not produce representative results of the concept expressed by the quantifier. To solve this type of problem, two aggregation operators, QMA–OWA, are proposed that use two quantification strategies and a quantified normalization process to model the semantic of the linguistic quantifiers in the group decision‐making process. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 193–208, 2006.     

Two‐dimensional beam‐scanning using tapered slot antennas and piezoelectric transducers

A wideband phased array is demonstrated using antipodal exponentially‐tapered slot‐antenna (ATSA) arrays operated by piezoelectric transducer (PET)‐controlled phase shifters. A 4 × 4 ATSA array is designed to scan two‐dimensionally across the entire X‐band. The phase shifters for 2D scanning consist of two sets of multiline phase shifters controlled by the PET for scanning in both planes. The 2D phased array has an antenna gain greater than 8 dBi, including all losses due to the phase shifters and transitions, and shows a wide beam‐scanning capability greater than 30° in both the E‐plane and the H‐plane. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

On the thru‐reflect‐line (TRL) numerical calibration and error analysis for parameter extraction of circuit model

In this work, a resistor standard is introduced into our previously proposed numerical thru‐reflect‐line (TRL) calibration procedure in order to determine the characteristic impedance of the line standard of calibration on the basis of a deterministic method of moments (MoM) algorithm. A comprehensive analytical derivation is presented with regards to electrical properties of such a resistor standard in comparison to other standards. In addition, an error analysis is detailed, which reveals correlations of characteristic parameters in connection with equivalent circuit model development from the conversions from field‐based S‐parameters to circuit‐based Y‐ or Z‐parameters. Interesting properties and criteria are derived, allowing accurate parameter extractions. To validate the proposed numerical TRL calibration procedure with this new resistor standard concept and the developed error analysis, the characteristic impedance of a microstrip line is extracted from a commercial software. In addition, a further example with microstrip discontinuity is shown and the effectiveness of the proposed technique is verified. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Bandpass filters using periodically loaded combline resonators

A novel combline filter is proposed for cellular‐radio base stations. The Q‐factor is significantly improved. The eigenvalue equation is expressed with the single‐team approximation in the gap region of the combline resonator. A two‐pole combline filter is designed. The calculation, simulation, and experiment results are presented and are in good agreement. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Control systems on regular time scales and their differential rings

The paper describes an algebraic construction of the inversive differential ring, associated with a nonlinear control system, defined on a nonhomogeneous but regular time scale. The ring of meromorphic functions in system variables is constructed under the assumption that the system is submersive, and equipped with three operators (delta- and nabla-derivatives, and the forward shift operator) whose properties are studied. The formalism developed unifies the existing theories for continuous- and discrete-time nonlinear systems, and accommodates also the case of non-uniformly sampled systems. Compared with the homogeneous case the main difficulties are noncommutativity of delta (nabla) derivative and shift operators and the fact that the additional time variable t appears in the definition of the differential ring. The latter yields that the new variables of the inversive closure, depending on t, have to be chosen to be smooth at each dense point t of the time scale.     

Fundamental analysis of harmonic reflection in microwave frequency triplers

Harmonic reflection is a vital technique for microwave frequency multiplier design, including the design of frequency triplers. In this article, principles of frequency tripler design with reflector networks are analyzed via harmonic‐balance simulation of an idealized MESFET/HEMT transistor model. The use of an idealized model allows fundamental mechanisms of 3f0 output power and conversion‐gain improvement via reflector networks to be characterized. Several reflector configurations are analyzed including: a 3f0 input reflector; a f0 output reflector; and a combination of both reflectors. The effects of reflector offset length on tripler performance are analyzed in terms of conversion gain, output power, reflected power, and time‐domain waveforms. As a result of this work, a greater understanding of harmonic‐reflector networks and their importance to tripler design is achieved. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Maps and isometries between indistinguishability operators

 In this paper, some geometric aspects of indistinguishability operators are studied by using the concept of morphism between them. Among all possible types of morphisms, the paper is focused on the following cases: Maps that transform a T-indistinguishability operator into another of such operators with respect to the same t-norm T and maps that transform a T-indistinguishability operator into another one of such operators with respect to a different t-norm T ^′. The group of isometries of a given T-indistinguishability operator is also studied and it is determined for the case of one-dimensional operators, in particular for the natural indistinguishability operators E _T on [0, 1]. Finally, the indistinguishability operators invariant under translations on the real line are characterized.     

Probe‐fed microstrip antennas loaded with very high‐permittivity ceramics

This article reports the feasibility study of miniaturizing probe‐fed microstrip patch antennas by dielectric loading. The loading materials are barium tetratitanate ceramics of very high dielectric constant (ε_r = 38, 80). It is shown that, simply through loading, the antenna sizes are greatly reduced; however, the antenna performances are deteriorated. For instance, the antenna gain becomes lower. Then enhancement of the antenna performances follows. A substrate–superstrate structure is used to recover the gain. Both the experiments and the finite‐difference time‐domain (FDTD) simulations demonstrate that the gain and impedance bandwidth can be retrieved such that they are comparable to those of conventional microstrip antennas loaded with low permittivity materials (ε_r < 3). © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Conditional diagnosability and strong diagnosability of shuffle-cubes under the comparison model

The growing size of multiprocessor systems increases the vulnerability to component failures. It is crucial to locate and replace faulty processors to maintain the system's high reliability. Processor fault diagnosis is essential to the reliability of a multiprocessor system and the diagnosabilities of many well-known networks (such as hierarchical hypercubes and crossed cubes [S. Zhou, L. Lin and J.-M. Xu, Conditional fault diagnosis of hierarchical hypercubes, Int. J. Comput. Math. 89(16) (2012), pp. 2152–2164 and S. Zhou, The conditional diagnosability of crossed cubes under the comparison model, Int. J. Comput. Math. 87(15) (2010), pp. 3387–3396]) have been investigated in the literature. A system is t-diagnosable if all faulty nodes can be identified without replacement when the number of faults does not exceed t, where t is some positive integer. Furthermore, a system is strongly t-diagnosable if it is t-diagnosable and can achieve (t+1)-diagnosability except for the case where a node's neighbours are all faulty. In addition, conditional diagnosability has been widely accepted as a new measure of diagnosability by assuming that any fault-set cannot contain all neighbours of any node in a multiprocessor system. In this paper, we determine the conditional diagnosability and strong diagnosability of an n-dimensional shuffle-cube SQ_n, a variant of hypercube for multiprocessor systems, under the comparison model. We show that the conditional diagnosability of shuffle-cube SQ_n (n=4k+2 and k≥2) is 3n?9, and SQ_n is strongly n-diagnosable under the comparison model.     

EGO: A personalized multimedia management and retrieval tool

The problems of content‐based image retrieval (CBIR) systems can be attributed to the semantic gap between the low‐level data representation and the high‐level concepts the user associates with images, on the one hand, and the time‐varying and often vague nature of the underlying information need, on the other. These problems can be addressed by improving the interaction between the user and the system. In this article, we sketch the development of CBIR interfaces and introduce our view on how to solve some of the problems these interfaces present. To address the semantic gap and long‐term multifaceted information needs, we propose a “retrieval in context” system, EGO. EGO is a tool for the management of image collections, supporting the user through personalization and adaptation. We will describe how it learns from the user's personal organization, allowing it to recommend relevant images to the user. The recommendation algorithm is described, which is based on relevance feedback techniques. Additionally, we provide results of a performance analysis of the recommendation system and of a preliminary user study. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 725–745, 2006.     

On the interpretation of fuzzy if then rules

The basic algorithm for reasoning in the fuzzy systems modeling method is introduced. Two classes of operators for interpreting the rules in these models are described, the Mamdani-Zadeh operator and the logical operator. The basic characteristics of these operators are presented and it is shown that the two classes of operators are distinguished by their response to a zero firing level. A class of Mamdani-Zadeh operators based upon the residuation operation is presented. A comparison is made between the performance of these residuation based Mamdani-Zadeh operators and the standard Mamdani-Zadeh operators derived from the t-norm. A new class of Mamdani-Zadeh operators based upon a generalization of the bounded difference is presented.