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The development of Goertler vortices with pre-set wavelength of 15 mm has been visualized in the boundary-layer on a concave surface of 2.0 m radius of curvature at a free-stream velocity of 3.0 m/s. The wavelength of vortices was...
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The development of Goertler vortices with pre-set wavelength of 15 mm has been visualized in the boundary-layer on a concave surface of 2.0 m radius of curvature at a free-stream velocity of 3.0 m/s. The wavelength of vortices was pre-set by vertical wires of 0.2 mm diameter located 10 mm upstream of the concave surface leading edge. The velocity contours in the cross-sectional planes at several stream wise locations show the growth and breakdown of the vortices. Three different regions can be identified based on different growth rate of the vortices. The occurrence of a secondary instability mode is indicated by the formation of a small horseshoe eddies generated between the two neighboring vortices traveling streamwise, to form mushroom-like structures as a consequence of the non-linear growth of the Gortler vortices.
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In this paper we use the notion of pre-open sets and pre-closed sets in topological space to prove the Cantor's intersection theorem for pre-closed sets.
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The formal content of near set theory can be summarised in terms of three concepts: a perceptual system, a nearness relation and a near set. Perceptual systems and different forms of nearness relations have been already successful...
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The formal content of near set theory can be summarised in terms of three concepts: a perceptual system, a nearness relation and a near set. Perceptual systems and different forms of nearness relations have been already successfully related to important mathematical structures (e. g., approach spaces) and described in the frameworks of general topology and category theory. However, since near sets actually do not form any regular structure, there is lack of similar results about the concept of a near set. The main goal of this paper is to fill this gap and provide a mathematical basis for near sets on a similar abstract level as it has been already done for nearness relations. However, we take in the paper a down-to-earth approach; that is, instead of seeking the richest mathematical structures which express our intuitions (call it up-to-sky approach), we present in the paper the simplest category theoretic structures which, however, are rich enough to convey our ideas. Thus, although many times we actually deal with sheaves, we speak about them as pre-sheaves. The main reason is that a sheaf (in contrast to a pre-sheaf) embodies the idea of gluing (in the very similar way like manifolds, which are obtainable by gluing open subsets of Euclidean space), which is irrelevant to the study of near sets and rough sets. Furthermore, the concept a pre-sheaf is much simpler than a sheaf and should be easily "digested" by readers who are not very familiar with category theory.
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In this paper we introduce and characterize the concept of fuzzy almost semi 8 -pre generalized continuous mappings. Several interesting properties of these mappings are also given. Examples and counter examples are also given to ...
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In this paper we introduce and characterize the concept of fuzzy almost semi 8 -pre generalized continuous mappings. Several interesting properties of these mappings are also given. Examples and counter examples are also given to illustrate the concepts introduced in the paper. We also introduce the concept of fuzzy semi δ -pre- T_(1/2), space,fuzzy S _(gpδ) space, fuzzy regular S_(gpδ) space and fuzzy semi δ -pre generalized compact space. It is seen that a fuzzy almost semi 8 -pre generalized continuous mapping from a fuzzy semi δ -pre- T_(1/2), space to another fuzzy topological space becomes fuzzy almost semi δ -pre continuous mapping.
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Optical burst switching networks have been receiving much attention as a promising approach to build the next-generation optical Internet. In this paper, we firstly describe the basic architecture of the optical burst switching ne...
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Optical burst switching networks have been receiving much attention as a promising approach to build the next-generation optical Internet. In this paper, we firstly describe the basic architecture of the optical burst switching network (OBS) based on dynamic wavelength routing (DWR), under which the guarantee of the quality of service (QoS) in the DWR-OBS network is discussed. Then we focus on two aspects: the transmission latency of the data packets and the blocking probability, which leads to a quantitative description of the transmission latency and the size of the edge node buffer. We also propose a method called dynamic preferred wavelength sets (D-PWS) to reserve the wavelength resource and based on the D-PWS entire-candidate path sets (E-CPS) wavelength assignment algorithm is given. Finally, we make a simulation on the DWR-OBS network by using the D-PWS method and take a comparison with the static preferred wavelength sets (S-PWS). The simulation shows that our approach excels traditional ones in QoS guarantee.
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The purpose of this paper is to introduce the concepts of fuzzy δ-semi pre open sets and fuzzy semi δ-pre open sets and to obtain a relation between them. We also introduce a new class of functions, called-weakly fuzzy δ-semi p...
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The purpose of this paper is to introduce the concepts of fuzzy δ-semi pre open sets and fuzzy semi δ-pre open sets and to obtain a relation between them. We also introduce a new class of functions, called-weakly fuzzy δ-semi pre open (closed) functions. Some characterization theorems are also to be established. Lastly, some applications are studied with the help of the above concepts.
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In this paper, we develop an adaptive neural strategy based on optimized backstepping (OB) technology for strict-feedback systems with unknown control directions and pre-set performance. First, the OB technique is used to construc...
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In this paper, we develop an adaptive neural strategy based on optimized backstepping (OB) technology for strict-feedback systems with unknown control directions and pre-set performance. First, the OB technique is used to construct each optimized virtual controller and optimized actual controller in backstepping, so as to achieve global optimization. Second, the problem of unknown control directions is overcome by using a Nussbaum-type function. Next, a time-varying switching function and the quartic barrier Lyapunov function are introduced to solve the control problem of the pre-set time and accuracy. The proposed control strategy makes the tracking error of the system converge to the pre-set accuracy within the pre-set time. At the same time, all of the signals of the closed-loop system are bounded. Finally, two set simulations verify the effectiveness of the proposed control strategy.(c) 2023 Elsevier B.V. All rights reserved.
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Using the idea of μ-pre*-closed set in generalized topological space, the concept of μ-pre*-closure and μ-pre*-interior in generalized topological space have been studied and several of their properties are proved. In this pape...
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Using the idea of μ-pre*-closed set in generalized topological space, the concept of μ-pre*-closure and μ-pre*-interior in generalized topological space have been studied and several of their properties are proved. In this paper we are introducing some new operators in μ-pre* closed sets in generalized topological space as μ-pre*- dervied, μ-pre*-border, μ-pre*-frontier and μ-pre*-exterior. Also the aim is to deal with some basic properties.
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We introduce some new types of sets called intuitionistic semi-open set, -open set, intuitionistic pre-open set and -open set in intuitionistic topological spaces.Also, we discuss some of their properties.
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