• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.176-184
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• 2013

Quantification of road noise is a challenging issue in the development of tire noise since its transfer paths are complicated. In this paper, a simplified model to estimate the road noise is developed. Transfer path of the model is from wheel to interior. The method uses the wheel excitation force estimated throughout inverse method. In inversion procedure, the Tikhonov regularization method is used to reduce the inversion error. To estimate the wheel excitation force, the vibration of knuckle is measured and transfer function between knuckle and wheel center is also measured. The wheel excitation force is estimated by using the measured knuckle vibration and the inversed transfer function. Finally interior noise due to wheel force is estimated by multiplying wheel excitation force in the vibro-acoustic transfer function. This vibro-acoustic transfer function is obtained throughout measurement. The proposed method is validated by using cleat excitation method. Finally, it is applied to the estimation of interior noise of the vehicle with different types of tires during driving test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.12
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• pp.935-942
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• 2014

The ride quality investigation is on-going topic in the car industry since its global standard has not evaluated and it is difficult to point out one part that hinders the ride quality. Since the traditional transfer path analysis that is widely used in car industry to investigate the ride quality requires a lot of test time to process the full data so that there are problems to conduct in industry. Based on these disadvantages, new approaches have developed such as OPAX(operational path analysis with eXogeneous inputs) and OTPA(operational transfer path analysis) for last decades. The OTPA only requires the operational data for evaluate the contribution of vibration sources and the OPAX has advantage of using parametric model to estimate the operating load and needs a minimum set of extra tests with excitation. In this paper, for evaluating the hindrance of ride quality two methods are used and the result is compared with another result of a car having higher ride quality.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.65-73
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• 2015

The ride quality has become a key component of not only design but car selling as the technology developed and the requirement of passengers grew up. Thus car industry invests lots of time and cost for the higher ride quality. The evaluation of the ride quality mainly is expressed by subjective element that drivers felt. In this paper, instead of the original transfer path analysis method, relatively new methods such as OPAX(Operational path analysis with eXogeneous inputs) and OTPA(operational transfer path analysis) are used for analyzing the main hindrance element of ride quality. With those new method, contribution rate of all paths that the vibration propagate along analyzed after driving test on the roads having different characteristic. The comprehensive hindrance elements of ride quality are deduced from the contribution rate and the improve experiment by changing one of hindrance elements for higher ride quality.

• The Journal of Information Systems
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• v.26 no.3
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• pp.187-209
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• 2017

Purpose The sharing economy is the most important keyword that is changing the paradigm of the world economy and management, and it was selected as one of 10 ideas to change the world in 2011 in Time magazine. The purpose of this study is to verify the structural relationship between perceived value and risk, network effect, usefulness, trust, and intention to use of accommodation service. In addition, the effects of utility and trust, and the experience of using accommodation service are controlled by the effect of empirical value and reciprocal value among the perceived value of sharing economic service, The purpose of this study is to propose a plan to activate the accommodation sharing service. Design/methodology/approach This study was designed to investigate the structural relationship between perceived value, perceived risk, network effect, usefulness, trust, and intention to use. Empirical analysis was done using SPSS 21.0 and AMOS 21.0 Findings Based on the results of this study, the following conclusions can be drawn. First, it was concluded that the higher the economic value of the accommodation sharing service is, the more useful and reliable the service is. Second, the higher the experiential value of the accommodation sharing service is, the higher the usefulness and reliability of the service are. Third, it was concluded that the higher the value of the mutual benefit of the accommodation sharing service is, the higher the trust level of the service is, but not the usefulness of the service. Fourth, it was concluded that the higher the perceived risk of accommodation sharing service is, the lower the service trust level is, but the service usability is not affected. Fifth, it was concluded that the larger the network effect of the accommodation sharing service is, the more useful the service is, but it does not affect the reliability of the service. Sixth, it was concluded that the higher the overall reliability of the accommodation sharing service is, the higher the usefulness of the service is. Seventh, it was concluded that the higher the overall usefulness and reliability of the accommodation sharing service are, the higher the intention to use the sharing service is. Finally, in order to test the effect of the experience on the use of trust and usefulness of the accommodation sharing service, multiple group analysis was conducted to examine the relationship between trust and usefulness, It is shown that there is a moderating effect in the path.

• Korean Journal of Social Welfare Studies
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• v.47 no.1
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• pp.151-178
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• 2016

The primary goal of the current study was to investigate the longitudinal relationship between household income, main caregiver depression, and youth aggression from the interactionist perspective. The data were derived by combining the 2006, 2009 and 2012 survey waves from the Korean Welfare Panel Study. This data set covered the full span of adolescence from elementary to high school. The study utilized 561 families as the final sample and conducted autoregressive cross-lagged analysis. As a result, the early income status, main caregiver depression and youth aggression were likely maintained over time. Second, the results provided support for a reciprocal relationship between income and main caregiver depression. On the other hand, the reciprocal relationship between main caregiver depression and youth aggression was not found in the current study. Finally, the mediating effect of main caregiver depression between income and youth aggression was not found in the present study. In conclusion, the results of this study support the interactionist model in that the association between family income and main caregiver depression involves reciprocity and mutual influence across time. These findings have major implications for policy and interventions in regards to low-income families.