• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.844-850
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• 2016

This study pertains to the extraction of the road noise component of signals from a vehicle's interior noise via the traditional frequency domain and time domain system identification methods. For road noise extraction based on the frequency domain system identification method, the appropriate matrix inversion strategy is investigated and causal and non-causal impulse response filters are compared. Furthermore, appropriate data lengths for the frequency domain system identification method are investigated. In addition to the traditional road noise extraction methods based on frequency domain system identification, a new approach to extract road noise via the time domain system identification method based on a parametric input-output model is proposed and investigated in the present study. In this approach, instead of constructing a higher order model for the full-band road noise, input and output signals are processed in the subband domain and lower order parametric models optimal to each subband are determined. These parametric models are used to extract road noises in each subband; the full band road noise is then reconstructed from the subband road noises. This study shows that both the methods in the frequency domain and the time domain successfully extract the road noise from the vehicle's interior noise.

• Journal of the Korean Home Economics Association
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• v.37 no.1
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• pp.45-65
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• 1999

The purpose of this study is to investigate the trend of the familism and the awareness of parent-supporting, showing how personal background variables affect the familism and how the familism affect the awareness of parent-supporting, The data were collected from May 20, 1998 till June 5, 1998 for 621 college students consisted of 300 male strdents and 321 female students. SOSS-PC was used for data analysis, and the data were tested by ANOVA, t-Test, Pearson's Correlation, Multiple Regression Analysis, and Duncan Test. The major findings are as follows: 1) The college students' familism generally tends to show low scores (M=2.79), indicating the modern familism-individualism. 2) The college students' awareness of parent-supporting is reported to be high(M=4.23); the highest awareness of parent-supporting is financial supporting, the next is service supporting, then emotinal supporting. 3) For personal background variables, male students rather than female students, the students who have parents with more monthly income, and those who have experience in living with grandparents tend to have more traditional familism. 4) Older students, the students with more traditional familism, those who find more satisfaction in family relations, and male students rather than female students tend to show higher awareness of parent-supporting. 5) In causal relations among the personal background variables, the familism, the awareness of parent-supporting, the variables with a significant impact on the familism are gender, parents' monthly income, and experience in living with grandparents, in order of impact. Age, the familism, satisfaction in family relations, and gender, in order of impact, affect the awareness of parent-supporting. Especially, the familism has the highest correlations with the awareness of financial, emotional, and service supporting, and shows considerable causal impact on the awareness of parent-supporting in general. That is to say, the more the familism, the more the awareness of the parent-supporting.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.556-563
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• 2002

In this paper, a novel method for designing an M-channel, causal, stable IIR cosine-modulated filter bank (CMFB) with near PR property is proposed. The IIR prototype filter is designed with a simple constraint using lattice stucture with 1st order allpass filter components. The IIR prototype filter which is designed by the proposed method has higher stopband attenuation and sharper roll-off characteristic than the one which is designed by the previously proposed method with similar complexity. The proposed M-channel IIR CMFB which is designed from this IIR prototype filter is applied to subband acoustic echo canceller (AEC). We obtained about 15dB higher ERLE using this subband AEC than when M-channel FIR subband AEC with similar complexity.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.163-172
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• 2021

This study aims to establish a research model to analyze the structural relationship between the working environment of the elderly medical welfare facility workers, the trust of the manager, and the quality of service. As a result, first, it was found that there was a significant causal relationship among service quality in the working environment of the elderly medical welfare facility workers. Second, it was found that there was a significant causal relationship between the working environment and the trust of managers of the elderly medical welfare facility workers. Therefore, in order to achieve the goal of the elderly medical welfare facility and improve the quality of service, it is necessary to create a working environment and establish a trust relationship among members. In addition, in order to cultivate competency and provide high-quality services for the elderly medical welfare facility workers, managers need to understand the individual characteristics of members, and to assign duties according to roles, accurate division of duties and personnel management are required.

• The Journal of Industrial Distribution & Business
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• v.9 no.5
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• pp.63-72
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• 2018

Purpose - This work analyzes, in detail, the specification of vector error correction model (VECM) and thus examines the relationships and impact among seven economic variables for USA - balance on current account (BCA), index of stock (STOCK), gross domestic product (GDP), housing price indices (HOUSING), a measure of the money supply that includes total currency as well as large time deposits, institutional money market funds, short-term repurchase agreements and other larger liquid assets (M3), real rate of interest (IR_REAL) and household credits (LOAN). In particular, we search for the main explanatory variables that have an effect on stock and real estate market, respectively and investigate the causal and dynamic associations between them. Research design, data, and methodology - We perform the time series vector error correction model to infer the dynamic relationships among seven variables above. This work employs the conventional augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) unit root techniques to test for stationarity among seven variables under consideration, and Johansen cointegration test to specify the order or the number of cointegration relationship. Granger causality test is exploited to inspect for causal relationship and, at the same time, impulse response function and variance decomposition analysis are checked for both short-run and long-run association among the seven variables by EViews 9.0. The underlying model was analyzed by using 108 realizations from Q1 1990 to Q4 2016 for USA. Results - The results show that all the seven variables for USA have one unit root and they are cointegrated with at most five and three cointegrating equation for USA. The vector error correction model expresses a long-run relationship among variables. Both IR_REAL and M3 may influence real estate market, and GDP does stock market in USA. On the other hand, GDP, IR_REAL, M3, STOCK and LOAN may be considered as causal factors to affect real estate market. Conclusions - The findings indicate that both stock market and real estate market can be modelled as vector error correction specification for USA. In addition, we can detect causal relationships among variables and compare dynamic differences between countries in terms of stock market and real estate market.

• Korean Business Review
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• v.22 no.1
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• pp.139-156
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• 2009

This article investigates the relationships between motivation and revisit intention of visitors to Gangneung Danoje Festival as cultural festival with social demand. Out of 550 questionnaires distributed, a total of 514 usable questionnaires were collected. The hypothesized causal model was tested by logit model, which included satisfaction model to each program as well as overall satisfaction model to cultural festival. Model 1 is constructed with satisfaction and revisit intention to each program, and Model 2 with overall satisfaction and revisit intention to cultural festival. In this models causal variables were inputted including satisfaction to festival programs, frequency of visitation, days of stay, time required to destination. In Model 1 positive sign were shown by causal variables as satisfaction to each program, frequency of visitation, days of stay but negative signs was shown by time required to festival place. In Model 2 sign directions of causal variables were same in Model 1. In comparison, Model 2 is more significant than Model 1 on the basis of statistical theory as significance level and coefficient of determination. Consequently, cultural festival managers should test the satisfaction level of visitors to each program of cultural festival and make efforts to establish advanced program in order to attract more visitors.

• Journal of Korea Technology Innovation Society
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• v.19 no.2
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• pp.324-357
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• 2016

As the transition to the knowledge-based economy has been accelerated in the 21st century, the importance of the service industry has been highlighted. As the proportion of knowledge service industry in the economy and the related employment rate are continuously growing, it is necessary to bring innovation to the industry in order to increase competitiveness. In this study, the innovation types are diversified into product, process, organization, and marketing and the influencing factors have been analyzed with knowledge service firms. The complex causal relationship that is linked to the innovation performance has been analyzed by the structural equation with each innovation types as the intervening variables. The results of this study can be summarized as follows. The innovation capacity of firms in knowledge service industry has very strong positive effects either directly or indirectly on product innovation, process innovation, organizational innovation, marketing innovation, and the revenue and employment of the firm. On the other hand, innovation support policy through government intervention produce negative impact on product innovation and they do not create meaningful impact on the total effect on the revenue nor the employment growth. The innovation should ultimately create effects on the revenue and the employment of the firm. And the government support policies should be carefully designed in consideration of the final destination point of this complex causal structure.

• Korean System Dynamics Review
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• v.8 no.1
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• pp.211-227
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• 2007

Like the saying "You can't manage what you can't measure," performance measurement is considered as one of the most important management activities for the organizations in either private or public sector. Performance measurement, however, has thus far relied too much on financial statements. Realizing the importance of a more scientific and comprehensive performance measurement, many organizations have adopted several different systems in order to objectively estimate their balanced performance results. The Balanced Scorecard (BSC) has become a popular means to measure performance. But the BSC has also received some criticisms. In this paper four limitations in the use of the BSC are discussed : BSCs focus on unidirectional causality, are unable to distinguish delays between actions and their impacts on performance, integrate insufficiently strategy with operational measures, and lead to internal biases. We propose a system dynamics approach with causal loop diagram(CLD) to develop a Dynamic BSC in order to overcome these limitations. The results suggest that developing a BSC with system dynamics is a promising approach to supplement existing BSC frameworks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.281-285
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• 2001

The design of injection molded polymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the part, which are not available to designers through current CAD systems. An interactive computer-based design system is developed in order to realize the concept of rational design for the productivity and quality of mold making. The knowledge-based CAD system is constructed by adding the knowledge-base module for mold feature synthesis and appropriate CAE programs for mold design analysis in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis performance analysis and feature-based geometric modeling. A knowledge-based CAD system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.933-937
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• 1995

The design of injection molded prlymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the parts. This study shows CAE approach for the design of the seat frame of fiber-reinforced composite material in order to realize the concept os rationsl design for the productivity and quality of mold making. The knowledge-based CAE system is constructed by adding the knowledge-basw module for the design evaluation and appropriate CAE programs for mold design analysis in order to provied designers, at the initial design stage, with comprehensive process knowledge for the performance analysis and the design evaluation. A knowledge-based CAE system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.