• Journal of applied mathematics & informatics
• /
• v.22 no.1_2
• /
• pp.263-271
• /
• 2006

In this paper, a quasilinear second-order system with periodic boundary conditions is studied. By the least action principle and classical theorems of variational calculus, existence results of periodic solutions are obtained.

• Journal of applied mathematics & informatics
• /
• v.38 no.5_6
• /
• pp.547-557
• /
• 2020

In this paper, we introduce the notions of (dual) residuated frames for a fuzzy logic as an extension of residuated frames for classical relational semantics. We investigate the relations between residuated connections and residuated frames on Alexandrov topologies based on [0, ∞]. Moreover, we study their properties and give their examples.

• Bulletin of the Korean Mathematical Society
• /
• v.31 no.2
• /
• pp.289-295
• /
• 1994

Let (A,G,.alpha.) be a $C^{*}$-dynamical system. In [3] the classical notions of ergodic properties of topological dynamical systems such as topological transitivity, minimality, and uniquely ergodicity are extended and analyzed in the context of non-abelian $C^{*}$-dynamical systems. We showed in [2] that if G is a compact group, then minimality, topological transitivity, uniquely ergodicity, and weakly ergodicity of the $C^{*}$-dynamical system (A,G,.alpha.) are equivalent.alent.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.2956-2958
• /
• 1999

The classical solution to the noise removal problem is the Wiener filter, which utilizes the second-order statistics of the Fourier decomposition. We discuss a Bayesian formalism which gives rise to a type of wavelet threshold estimation in non-parametric regression. A prior distribution is imposed on the wavelet coefficients of the unknown response function, designed to capture the sparseness of wavelet expansion common to most application. For the prior specified, the posterior median yields a thresholding procedure

• Journal of applied mathematics & informatics
• /
• v.42 no.4
• /
• pp.819-829
• /
• 2024

This paper delves into an examination of both non-Bayesian and Bayesian estimation techniques for determining the Topp-leone inverse Weibull distribution parameters based on progressive Type-II censoring. The first approach employs expectation maximization (EM) algorithms to derive maximum likelihood estimates for these variables. Subsequently, Bayesian estimators are obtained by utilizing symmetric and asymmetric loss functions such as Squared error and Linex loss functions. The Markov chain Monte Carlo method is invoked to obtain these Bayesian estimates, solidifying their reliability in this framework.

• Journal of the Korean Society of Costume
• /
• v.63 no.6
• /
• pp.69-83
• /
• 2013

This research is to analyze costumes of Greek Mythology Gods in films using Morris' semiotics. In film "Clash of The Titans", Zeus' costume of shining gold armored body suit and long manteaux expressed the limitless sublime. The definite form contouring body shape of his costume also demonstrated classical beauty. Hades' costume of dark colored armor, long manteaux, and transformation via smoke also described the limitless sublime. The unbalanced and irregular shaped armor showed ugliness. In "Percy Jackson & The Olympians: The Lightening Thief", the armor and long manteaux of Zeus showed the limitless sublime. The beauty of his body and his sophisticated business wear indicated classical beauty. These features were also present in Poseidon's costume as well. The limitless sublime and ugliness are implied in Hades' look by portraying him as having a monster body with horns and wings, and his costume of punk look. In "Immortals", gods of Olympus wore clothing that was reminiscent of Egyptian times, which represented a time of strong royal authority, in order to expose the limitless sublime. Classical beauty was shown in the beauty of their body. Titans' costumes and look of non-human being were composed of black and red to present ugliness. The inherent meanings of Gods' costumes are death of god, patriarchy, and the good triumphing over the evil. The Greek gods are not held in the same reverence in the contemporary society. However mythology inspires lots of visual creations. The results help to accumulate a creative design database for fashion.

• Journal of Oriental Neuropsychiatry
• /
• v.32 no.2
• /
• pp.111-127
• /
• 2021

Objectives: To review and analyze clinical and preclinical evidence of effectiveness, safety, and underlying mechanisms of yokukansan (YKS), a herbal medicine, in alleviating aggression. Methods: Classical records on YKS were searched in the Korean Traditional Medicine Knowledge Database (KTMKD). By searching five electronic databases, prospective clinical studies and preclinical studies of YKS for alleviating aggression/agitation published up to March 30, 2021 were included. Results: Only two classical records on YKS were found from the KTMKD. A total of 11 clinical studies and 15 preclinical studies were found from the five electronic databases. Among 11 clinical studies, seven enrolled patients with dementia and four enrolled patients with other neuropsychiatric disorders. Most clinical studies reported significant improvement in one or more outcomes related to aggression in the YKS group after treatment. Among 15 preclinical studies, all studies except two reported a significant decrease in aggression/agitation-related behavior of YKS or yokukansankachimpihange. Suggested underlying mechanisms of YKS or yokukansankachimpihange for aggression/agitation in these studies included regulation of serotonin receptor, amelioration of abnormal glucocorticoid level related to the hypothalamic-pituitary-adrenal axis, regulation of orexin secretion, amelioration of degeneration in brain cells including glia cells, and suppression of excessive glutamatergic or dopaminergic activity. Conclusions: There were some clinical and preclinical evidence supporting the effectiveness and safety of YKS for alleviating aggression. Given that aggression is the most frequent and destructive symptoms of behavioral and psychological symptoms of dementia, applicability of YKS as a herbal medicine should be further investigated in future high-quality research.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.10a
• /
• pp.134-143
• /
• 2006

Out of all types of motions the critical motions leading to capsize is roll. The dynamic amplification in case of roll motion may be large for ships as roll natural frequency generally falls within the frequency range of wave energy spectrum typical used for estimation of motion spectrum. Roll motion is highly non-linear in nature. Den are various representations of non-linear damping and restoring available in literature. In this paper an uncoupled non-linear roll equations with three representation of damping and cubic restoring term is solved using a perturbation technique. Damping moment representations are linear plus quadratic velocity damping, angle dependant damping and linear plus cubic velocity dependant damping. Numerical value of linear damping coefficient is almost same for all types but non-linear damping is different. Linear and non-linear damping coefficients are obtained form free roll decay tests. External rolling moment is assumed as deterministic with sinusoidal form. Maximum roll amplitude of non-linear roll equation with various representations of damping is calculated using analytical procedure and compared with experimental results, which are obtained form forced tests in regular waves by varying frequency with three wave heights. Experiments indicate influence of non-linearity at resonance frequency. Both experiment and analytical results indicates increase in maximum roll amplitude with wave slope at resonance. Analytical results are compared with experiment results which indicate maximum roll amplitude analytically obtained with angle dependent and cubic velocity damping are equal and difference from experiments with these damping are less compared to non-linear equation with quadratic velocity damping.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.1
• /
• pp.26-32
• /
• 2019

The vortex flow behind a bluff body has been a subject of interest for a very long time because of its engineering applicability such as to vortex induced vibration. In the near wake of a bluff body, vortices are periodically shed in two shear layers, which originate in the trailing edges. The far wake is made up of the classical Karman vortices, which are connected together by streamwise and spanwise vortices. These vortex formations have been studied in many experimental and numerical ways. However, most of the studies considered non-cavitating flow. In this study, we investigated cavitating flow in the wake of a two-dimensional wedge. Experiments were conducted in a cavitation tunnel of Chungnam National University. Using a particle image velocimetry (PIV), we measured the velocity fields under two different flow conditions: non-cavitating and cavitating regimes. We also investigated the vortex shedding frequencies using an absolute pressure transducer mounted on the top of the test window. Throughout the experiments, it was found that the shedding frequency of the vortex was strongly affected by cavitation, and the Strouhal number could exceed its value in the non-cavitating regime.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.4
• /
• pp.301-309
• /
• 2021

Pulse count method is the classical reaction wheel speed detection method. In this study, we represent the pulse count method as mathematical equations. Instead of rotation speed, we model the reaction wheel rotation through rotation angle during sampling periods. We verified the effectiveness of the proposed model by comparing the pulse counts variation and averaging method effects from the model and previous research results. Then, we add tacho pulse non-uniformity to this verified model, and examine the errors of pulse count method. We express the measurement error increasement due to non-uniformity as mathematical equations, and also shows the requirement of moving average numbers to offset the measurement errors.