• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.7
• /
• pp.561-568
• /
• 2004

The nonlinear dynamic characteristic of a straight tube conveying fluid with constraints and an attached mass on the tube is examined in this study An experimental apparatus with an elastomer tube conveying water which has an attached mass and constraints is made and comparisons are made between the theoretical results from the non-linear equation of motion of piping system and the experimental results. The comparisons show that the tube is destabilized as the magnitude of the attached mass increases, and stabilized as the position of the attached mass closes to the fixed end. In case of a small end-mass, the system shows complicated and different types of solutions. For a constant end-mass. the system undergoes a series of bifurcations after the first Hopf bifurcation, as the flow velocity increases. which causes chaotic motions of the tube eventually.

• Journal of the Korean Society of Costume
• /
• v.62 no.5
• /
• pp.1-15
• /
• 2012

In a fast changing postmodern society, contemporary fashion is becoming more complicated and ambiguous along with other genres of art than ever before. This phenomenon reigning as a sociocultural paradigm can be defined as 'indeterminacy' and it means 'undecidability'. The purpose of this study is to clarify and analyze the indeterminate characteristics of contemporary fashion reviewing the theoretical background and the architectural formativeness as a comparative research. The core idea of deconstructivism dismantles a causal relationship between function and form in fashion and the conventional notion about clothes. Complexity theory, which is the study of chaotic dynamical systems, suggests the creative idea and concept of infinite possibilities on a formative method. Meanwhile, catastrophe theory of discontinuous change can be used as interpretative strategies for the process of deconstruction and reconstruction. As a result of this study, the indeterminacy of fashion can be analyzed into five semantic categories: irregularity, immateriality, randomness, complexity and changeability. The intrinsic value of the indeterminacy in contemporary fashion is the interaction with a sociocultural ideology and a technological environment as well as an expansion of formative expression. To conclude, it can be said that the indeterminacy in fashion is a new interpretation of the relationship among body and space, clothes and society.

• Journal of the Korean Mathematical Society
• /
• v.56 no.6
• /
• pp.1561-1597
• /
• 2019

In this paper we introduce the notions of topological entropy and topological pressure for non-autonomous iterated function systems (or NAIFSs for short) on countably infinite alphabets. NAIFSs differ from the usual (autonomous) iterated function systems, they are given [32] by a sequence of collections of continuous maps on a compact topological space, where maps are allowed to vary between iterations. Several basic properties of topological pressure and topological entropy of NAIFSs are provided. Especially, we generalize the classical Bowen's result to NAIFSs ensures that the topological entropy is concentrated on the set of nonwandering points. Then, we define the notion of specification property, under which, the NAIFSs have positive topological entropy and all points are entropy points. In particular, each NAIFS with the specification property is topologically chaotic. Additionally, the ${\ast}$-expansive property for NAIFSs is introduced. We will prove that the topological pressure of any continuous potential can be computed as a limit at a definite size scale whenever the NAIFS satisfies the ${\ast}$-expansive property. Finally, we study the NAIFSs induced by expanding maps. We prove that these NAIFSs having the specification and ${\ast}$-expansive properties.