• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.435-440
• /
• 2000

It is shown, in nonlinear two-degree-of freedom system, that the bifurcating modes are created by the stability changes of normal modes. There are four types of stability criterion, each of which gives rise to a distinct functional form of bifurcating modes; the bifurcating mode is born in the form of eigenfunction through which the stability is changed. Then a procedure is formulated to compute the bifurcating mode by the method of harmonic balance. Application of bifurcating mode to forced vibrations is introduced.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.3_1spc
• /
• pp.525-530
• /
• 2013

The objective of the present study is to investigate the heat transfer characteristics of turbulent impinging jets with bifurcating excitations. Bifurcating excitations use the dual mode, dual frequency forcing, where an axial forcing frequency is equal to double the helical forcing frequency. Under the bifurcating excitation, the heat transfer significantly increases in one plane (bifurcating plane), while nearly no heat transfer occurs in the perpendicular plane (bisecting plane). This result is closely associated with the change in the vortical structures caused by the excitation.

• Journal of the Korean Mathematical Society
• /
• v.49 no.4
• /
• pp.715-731
• /
• 2012

This paper considers the stability of positive steady-state solutions bifurcating from the trivial solution in a delayed Lotka-Volterra two-species predator-prey diffusion system with a discrete delay and subject to the homogeneous Dirichlet boundary conditions on a general bounded open spatial domain with smooth boundary. The existence, uniqueness and asymptotic expressions of small positive steady-sate solutions bifurcating from the trivial solution are given by using the implicit function theorem. By regarding the time delay as the bifurcation parameter and analyzing in detail the eigenvalue problems of system at the positive steady-state solutions, the asymptotic stability of bifurcating steady-state solutions is studied. It is demonstrated that the bifurcating steady-state solutions are asymptotically stable when the delay is less than a certain critical value and is unstable when the delay is greater than this critical value and the system under consideration can undergo a Hopf bifurcation at the bifurcating steady-state solutions when the delay crosses through a sequence of critical values.

• Bulletin of the Korean Mathematical Society
• /
• v.60 no.1
• /
• pp.257-279
• /
• 2023

Applying the Lyapunov-Schmidt reduction, we consider spectral stability of small amplitude stationary periodic solutions bifurcating from an equilibrium of the generalized Swift-Hohenberg equation. We follow the mathematical framework developed in [15, 16, 19, 23] to construct such periodic solutions and to determine regions in the parameter space for which they are stable by investigating the movement of the spectrum near zero as parameters vary.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.5
• /
• pp.1137-1149
• /
• 2014

Since the bifurcating autoregressive (BAR) model was developed by Cowan and Staudte (1986) to analyze cell lineage data, a lot of research has been directed to BAR and its generalizations. Based mainly on the author's works, this paper is concerned with a contemporary review on the BAR in terms of an overview and perspectives. Specifically, bifurcating structure is extended to multi-cast tree and to branching tree structure. The AR(1) time series model of Cowan and Staudte (1986) is generalized to tree structured random processes. Branching correlations between individuals sharing the same parent are introduced and discussed. Various methods for estimating parameters and related asymptotics are also reviewed. Consequently, the paper aims to give a contemporary overview on the BAR model, providing some perspectives to the future works in this area.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.5
• /
• pp.1067-1072
• /
• 2012

Recently, linear motors have been widely researched and have been increasingly used in various industrial applications. Especially, permanent magnet linear synchronous motors(PMLSMs) have been getting the spotlight in the transportation system. A PMLSM is structurally simple and has a lot of merits such as high speed, high thrust force, etc. However, in case of a long stator system which arranges armature to the full length of transportation lines, a PMLSM has some disadvantages such as the material cost increase and long manufacturing time. Hence, in order to overcome these problems, the PMLSM with stationary discontinuous armature structure and concentrated windings was proposed. However, this method occurs undesirable cogging force by outlet edge effect. The cogging force causes thrust force ripples and generates noise and vibration. Therefore, in this paper, we proposed installation method of auxiliary pole PMLSM with concentrated winding applying bifurcating in order to reduce cogging force by the outlet edge when the armature is placed in a discontinuous arrangement. Also, we have examined characteristics of outlet edge cogging force using 2-D finite element analysis(FEA).

• Journal of the Korean Statistical Society
• /
• v.35 no.4
• /
• pp.409-417
• /
• 2006

This article is concerned with threshold modeling of the bifurcating autoregressive model (BAR) originally suggested by Cowan and Staudte (1986) for tree structured data of cell lineage study where each individual $(X_t)$ gives rise to two off-spring $(X_{2t},\;X_{2t+1})$ in the next generation. The triplet $(X_t,\;X_{2t},\;X_{2t+1})$ refers to mother-daughter relationship. In this paper we propose a threshold model incorporating the difference of 'fertility' of the mother for the first and second off-springs, and thereby extending BAR to threshold-BAR (TBAR, for short). We derive a sufficient condition of stationarity for the suggested TBAR model. Also various inferential methods such as least squares (LS), maximum likelihood (ML) and quasi-likelihood (QL) methods are discussed and relevant limiting distributions are obtained.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.794-797
• /
• 2002

We consider a master-slave pulse-coupled network of bifurcating integrate-and-fire circuits. The network exhibits in-phase chaotic synchronization and various periodic synchronization phenomena. In order to analyze these phenomena precisely, we derive a one-dimensional return map. Also using a simple test circuit, typical phenomena are demonstrated in the laboratory.

• Korean Institute of Interior Design Journal
• /
• v.14 no.1
• /
• pp.20-27
• /
• 2005

This study is focused on the concept and spatial organization of bifurcation. After discussing the concept of bifurcation used in Borges' literature and Deleuze's Fold philosophy, case examples in contemporary architecture are analysed to comparatively investigate the relationship between the concept and space. In Deleuze's philosophy, bifurcation as well as pleats, inflection are used to form the world of fold that goes to infinity while, in Borges' literature, the structure of bifurcation is the key method to create the labyrinth of time. There are various projects in contemporary architecture based on the Deleuzian concept of bifurcation. Rem Koolhaas's Two Libraries for Jussieu University and UN Studio's Arnhem Central are selected and researched for further comparison study. In Jussieu project, the bifurcating spatial organization is 'intentionally' used to construct the indeterminant space whereas in Arnhem Central, bifurcation can be found in both the ever-bifurcating design process as well as the final spatial organization'unintentionally'generated from the process. This study is concluded with the comparative analysis between the representation and actualization of a concept that are crucially different.

• Journal of the Korean earth science society
• /
• v.35 no.5
• /
• pp.299-304
• /
• 2014

In this study, fossil liverwort (Hepaticae) of Thallites yabei (Kryshtofovich) Harris is described based on the newly obtained material from the Lower Cretaceous Nakdong Formation of Sindong Group, Korea. The thalli of T. yabei is ribbon-like, bifurcating at least three or four times, and has a distinct midrib. Although the thalloid plants are herbaceous with little hard part, the thalli of T. yabei is relatively well preserved to show the sequentially bifurcating pattern in the specimens occurred in the same fossil locality. Such characteristics indicate that they were probably buried in situ. The abundant occurrence of thalli plants also indicate that land was covered densely by them as one of the terrestrial land plant members, and flourished under the tall arbor trees in the humid environment during the Early Cretaceous in the Gyeongsang Basin.