• Journal of Mechanical Science and Technology
• /
• v.20 no.12
• /
• pp.2147-2158
• /
• 2006

The continuous wavelet transform (CWT) has a frequency-adaptive time-frequency tiling property, which makes it popular for the analysis of dispersive elastic wave signals. However, because the time-frequency tiling of CWT is not signal-dependent, it still has some limitations in the analysis of elastic waves with spectral components that are dispersed rapidly in time. The objective of this paper is to introduce an advanced time-frequency analysis method, called the dispersion-based continuous wavelet transform (D-CWT) whose time-frequency tiling is adaptively varied according to the dispersion relation of the waves to be analyzed. In the D-CWT method, time-frequency tiling can have frequency-adaptive characteristics like CWT and adaptively rotate in the time-frequency plane depending on the local wave dispersion. Therefore, D-CWT provides higher time-frequency localization than the conventional CWT. In this work, D-CWT method is applied to the analysis of dispersive elastic waves measured in waveguide experiments and an efficient procedure to extract information on the dispersion relation hidden in a wave signal is presented. In addition, the ridge property of the present transform is investigated theoretically to show its effectiveness in analyzing highly time-varying signals. Numerical simulations and experimental results are presented to show the effectiveness of the present method.

• Journal of KIISE:Databases
• /
• v.35 no.4
• /
• pp.307-318
• /
• 2008

One of the primary issues confronting XML message brokers is the difficulty associated with processing a large set of continuous XPath queries over incoming XML seams. This paper proposes a novel system designed to present an effective solution to this problem. The proposed system transforms multiple XPath queries before their run-time into a new region-based data structure, called an XP-table, by sharing their common constraints. An XP-table is matched with a stream relation (SR) transformed from a target XML stream by a SAX parser. This arrangement is intended to minimize the runtime workload of continuous query processing. Also, system performance is estimated and verified through a variety of experiments, including comparisons with previous approaches such as YFilter and LazyDFA. The proposed system is practically linear- scalable and stable for evaluating a set of XPath queries in a continuous and timely fashion.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.8
• /
• pp.25-39
• /
• 2019

This study analyzed the relation among middle-aged women's interesting factor of golf and intention of continuous behavior and verified the mediation effect of Flow in leisure. The purpose is to clarify the process in which middle-aged women'change their life to positive direction through golf activity and to provide basic data on the basis of theoretic fundamental. The data was processed with Confirmatory Factor Analysis(CFA) & Structural Equation Model(SEM) by using Exploratory Factor Analysis(EFA) & AMOS 25.0 statistical program through SPSS 25.0 Window Version. The result is as follows. First, interesting factor of golf is found to have significant influence on Flow of leisure. Second, interesting factor of golf is found to have significant influence on intention of continuous behavior. Third, Flow of leisure is found to have significant influence on intention of continuous behavior. Finally, Flow of leisure is found to have partial mediation effect in the relation among interesting factor of golf and intention of continuous behavior. Thus, it is judged that enjoyment should be ensured precedently through the interesting factors of golf to develop golf industry and to induce middle-aged women golf participants to golf course. It is thought that diversified methods which can increase satisfaction by utilizing leisure immersion and which can ensure constant participation for this purpose.

• Communications of the Korean Mathematical Society
• /
• v.25 no.1
• /
• pp.97-104
• /
• 2010

The article is devoted to exhibit some general properties of strong chain recurrent set and strong chain transitive components for a continuous map f on a compact metric space X. We investigate the relation between the weak shadowing property and strong chain transitivity. It is shown that a continuous map f from a compact metric space X onto itself with the average shadowing property is strong chain transitive.

• Honam Mathematical Journal
• /
• v.40 no.1
• /
• pp.13-25
• /
• 2018

In this paper a general fixed point theorem for two pairs of mappings involving altering distance is proved. This theorem generalizes Theorem 9 [5], Theorems 1, 2, 3 [6], Theorems 2.3, 2.4 [7] and other results from [11]. As applications, some results for mappings satisfying contractive conditions of integral type and ${\phi}$-contractive conditions are obtained.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.4
• /
• pp.77-83
• /
• 2020

The Linear system analysis for physical system is very powerful tool for system diagnostic utilizing relationship between the input signal and output signal. This method utilized generally to investigate physical properties of system and the nondestructive test by ultrasonic signals. This method can be explained by linear system theory. In this paper the Continuous Wavelets Transform is utilized to search the relation between the linear system and continuous wavelets transform.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.2
• /
• pp.101-108
• /
• 2004

Recently, a semi-active shock absorber has been taking interest because of its low cost and simple structure than the active one. CFD analysis has been conducted to investigate the continuous and variable damping characteristics of the semi-active shock absorber. Also, the flow resistance characteristics of a spool valve has been examined to identify individual parameters(namely, exponent and discharge coefficient) of pressure-flow rate relation needed for the accurate valve modeling. The flow field in the damping valve was simulated using the commercial code, CFX-5.3. The numerical results showed reasonable agreement with the experimental outputs. The pressure distribution with the variation of spool opening length and volume flow rate were discussed in detail. And the continuous and variable damping performance was found clearly. The individual parameters of spool valve were obtained as a function of orifice area. The exponent and discharge coefficient were fitted in with the first and the third polynomial respectively.

• Environmental Analysis Health and Toxicology
• /
• v.16 no.4
• /
• pp.153-159
• /
• 2001

The main point source of pollution of the Keumho river in Taegu, Korea, stems from waste from the areas of industrial complexes . Although it is widely accepted that pollutants in waste water negatively effects general water quality, it is difficult to evaluate the effluent effect because of varying conditions in ambient water and inconclusive knowledge of causative pollutants. To analyze the water in relation to the industrial effluent in the area, pH. temperature, conductivity, and Microtox toxicity of various river samples were measured. Water samples were collected every 2 hours for 36 hours from Keumho river and Dalseo stream. Data from continuous monitoring for 36 hours showed that effluent in Keumho river originated from Dalseo stream, which is near adjacent to industrial complexes. Change in toxicity and other factors tested during the 36 hours indicated that continuous monitoring was necessary for a satisfactory effluent toxicity test Furthermore, in addition to water quality monitoring, it was concluded that sediment toxicity also needed to evaluate effluent effects.

• Journal of Mechanical Science and Technology
• /
• v.16 no.4
• /
• pp.454-467
• /
• 2002

It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. Toidentifythelocation and depth of a crack in a structure, a method is presented in this paper which uses neuro-fuzzy-evolutionary technique, that is, Adaptive-Network-based Fuzzy Inference System (ANFIS) solved via hybrid learning algorithm (the back-propagation gradient descent and the least-squares method) and Continuous Evolutionary Algorithms (CEAs) solving sir ale objective optimization problems with a continuous function and continuous search space efficiently are unified. With this ANFIS and CEAs, it is possible to formulate the inverse problem. ANFIS is used to obtain the input(the location and depth of a crack) - output(the structural Eigenfrequencies) relation of the structural system. CEAs are used to identify the crack location and depth by minimizing the difference from the measured frequencies. We have tried this new idea on beam structures and the results are promising.

• Resources Recycling
• /
• v.12 no.2
• /
• pp.11-20
• /
• 2003

Limestone mine waste was used as a aggregate far permeable concrete. Void ratio, continuous void ratio, coefficient of permeability, compressive strength and flexural strength of concrete were measured and then the relationship between porosity and strength properties was investigated. Void ratio, continuous void ratio and strength properties of permeable concrete were greatly influenced by the grain size of aggregate and void filling ratio in comparison with the containing ratio of limestone mine waste. Furthermore, void ratio showed a good relation with continuous void ratio, and porosity of permeable concrete indicated a good relation with strength properties also. The coefficient of permeability of permeable concrete using limestone waste was over 0.2 cm/sec and was excellent result in comparison with normal concrete. Therefore, it could be expected that the limestone mine waste would be utilized as aggregate for pavement concrete, green concrete and water resource specie concrete in the results of this study.