21 research outputs found

    Resolution and simplification of Dombi-fuzzy relational equations and latticized optimization programming on Dombi FREs

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    In this paper, we introduce a type of latticized optimization problem whose objective function is the maximum component function and the feasible region is defined as a system of fuzzy relational equalities (FRE) defined by the Dombi t-norm. Dombi family of t-norms includes a parametric family of continuous strict t-norms, whose members are increasing functions of the parameter. This family of t-norms covers the whole spectrum of t-norms when the parameter is changed from zero to infinity. Since the feasible solutions set of FREs is non-convex and the finding of all minimal solutions is an NP-hard problem, designing an efficient solution procedure for solving such problems is not a trivial job. Some necessary and sufficient conditions are derived to determine the feasibility of the problem. The feasible solution set is characterized in terms of a finite number of closed convex cells. An algorithm is presented for solving this nonlinear problem. It is proved that the algorithm can find the exact optimal solution and an example is presented to illustrate the proposed algorithm.Comment: arXiv admin note: text overlap with arXiv:2206.09716, arXiv:2207.0637

    An exact algorithm for linear optimization problem subject to max-product fuzzy relational inequalities with fuzzy constraints

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    Fuzzy relational inequalities with fuzzy constraints (FRI-FC) are the generalized form of fuzzy relational inequalities (FRI) in which fuzzy inequality replaces ordinary inequality in the constraints. Fuzzy constraints enable us to attain optimal points (called super-optima) that are better solutions than those resulted from the resolution of the similar problems with ordinary inequality constraints. This paper considers the linear objective function optimization with respect to max-product FRI-FC problems. It is proved that there is a set of optimization problems equivalent to the primal problem. Based on the algebraic structure of the primal problem and its equivalent forms, some simplification operations are presented to convert the main problem into a more simplified one. Finally, by some appropriate mathematical manipulations, the main problem is transformed into an optimization model whose constraints are linear. The proposed linearization method not only provides a super-optimum (that is better solution than ordinary feasible optimal solutions) but also finds the best super-optimum for the main problem. The current approach is compared with our previous work and some well-known heuristic algorithms by applying them to random test problems in different sizes.Comment: 29 pages, 8 figures, 7 table

    Perfectionism Search Algorithm (PSA): An Efficient Meta-Heuristic Optimization Approach

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    This paper proposes a novel population-based meta-heuristic optimization algorithm, called Perfectionism Search Algorithm (PSA), which is based on the psychological aspects of perfectionism. The PSA algorithm takes inspiration from one of the most popular model of perfectionism, which was proposed by Hewitt and Flett. During each iteration of the PSA algorithm, new solutions are generated by mimicking different types and aspects of perfectionistic behavior. In order to have a complete perspective on the performance of PSA, the proposed algorithm is tested with various nonlinear optimization problems, through selection of 35 benchmark functions from the literature. The generated solutions for these problems, were also compared with 11 well-known meta-heuristics which had been applied to many complex and practical engineering optimization problems. The obtained results confirm the high performance of the proposed algorithm in comparison to the other well-known algorithms

    Interfacial bond strength of coloured SCC repair layers : an experimental and optimisation study

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    This study investigates experimentally and analytically the interfacial bond strength of coloured SCC repair layers. Ten SCC mixes with 5%, 10% and 15% of blue, green or red pigments were produced to examine their fresh properties. Subsequently, 60 coloured SCC specimens were tested to assess interfacial bond strength using pull-off and push-out tests. The results confirm that pigments reduce the mechanical properties of SCC and its bond strength to concrete substrates, with red pigment reducing (by up to 41%) interfacial bond strength. It is shown that the push-out test is effective to determine the interfacial shear bond strength between the SCC repair layers and substrates. A GNNC-Modified PSO algorithm is proposed to calculate accurately (R2ā€‰=ā€‰0.95) the interfacial bond strength of coloured SCC repair layers. This study contributes towards developing more effective test methods and more accurate models to calculate interfacial bond strength of the SCC repair layers used in this study

    Properties of fibre-reinforced self-compacting concrete subjected to prolonged mixing : an experimental and fuzzy logic investigation

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    This article investigates the effect of prolonged mixing on the rheological properties and compressive strength of fibre-reinforced self-compacting concretes (FRSCCs). Twenty FRSCC mixes with five cementitious material contents (300, 350, 400, 450 and 500 kg/m3) and three types of fibres and dosages (polypropylene at 0.1%, steel at 1.0%, or synthetic at 1.0%) were first produced. The mixes were then subjected to four mixing intervals of 20 min each (total mixing time = 80 min). The rheological properties of the fresh FRSCC mixes were examined, and the corresponding compressive strength of the hardened FRSCCs was subsequently obtained. Overall, the results from slump flow, T50, V-funnel and L-box tests on fresh mixes, as well as the 28-day compressive strength on the hardened FRSCCs, were in line with previous results reported in the literature. The results show that all mixes lost their self-compacting properties after 80 min of mixing. It was also found that mixes with high cementitious material contents (500 kg/m3) and highest polypropylene fibre dosage were most affected by prolonged mixing, with average losses of 30% and 35% in rheological properties and compressive strength, respectively. Based on the test results, this study proposes a novel fuzzy logic approach to predict the slump loss and at 28-day compressive strength loss of FRSCCs subjected to prolonged mixing. This article contributes towards a better understanding of FRSCCs after prolonged mixing, which can help make informed decisions about their use in new and repaired concrete structures

    The semiring-theoretic approach to MV-algebras: a survey

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    In this paper we review some of the main achievements of the semiring-theoretic approach to MV-algebras initiated and pursued mainly by the present authors and their collaborators. The survey focuses mainly on the connections between MV-algebras and other theories that such a semiringbased approach enabled, and on an application of such a framework to Digital Image Processing. We also give some suggestions for further developments by stating several open problems and possible research lines.Comment: Published versio

    Techniques for immobilizing enzymes to create durable and effective biocatalysts

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    This comprehensive review focuses on strategies for creating efficient and robust immobilized biocatalysts. It explores various physicochemical approaches that hold promise for enzyme stabilization and enhancement of catalytic potential. One approach involves designing enzyme stabilization on permeable scaffolds, emphasizing the importance of the support structure and the ability to fine-tune biocatalyst activity. Another pathway is establishing covalent bonds between enzymes and support surfaces, anchoring the biocatalysts for longevity and sustained activity in industrial and research applications. Polymers are also used to modify the structure and formulation of immobilized enzymes, enhancing stability and providing a versatile platform for biocatalytic reactions. These approaches are particularly valuable when enzymes are immobilized within pre-established permeable scaffolds. They enable researchers and engineers to utilize biocatalysis in diverse applications, such as biopharmaceutical production and sustainable chemical synthesis. Furthermore, these fixed-stabilized enzyme derivatives offer significant advancements in enzyme reaction optimization and reactor design. The reported enhancements in catalytic activity are remarkable, with performance gains ranging from 500 to an impressive 20,000-fold compared to diluted soluble enzymes. In summary, this review highlights the importance of innovative strategies for developing immobilized biocatalysts. It presents exciting avenues for researchers and industries seeking to harness the catalytic potential of enzymes in various applications. These advancements not only promise enhanced efficiency but also contribute to sustainable and environmentally friendly chemical processes
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