• Structural Engineering and Mechanics
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• v.60 no.6
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• pp.1079-1092
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• 2016

In this paper, an electromechanical integrated harmonic piezodrive system is proposed. The operating principle of the drive system is introduced. The equation of the relationship between the displacements of the flexible ring and the rotating angle of the rotor is deduced. Using the equation, the displacements of the flexible ring for the drive system and their changes along with the system parameters are investigated. The results show that the displacements of the flexible ring changes periodically along with the rotation of the vibrator; there are abrupt changes in the displacements of the flexible ring at some points where there are abrupt changes in the number of the mesh teeth pair; the length of the flexible ring, the excitation voltage, and the speed ratio have obvious effects on the displacements of the flexible ring. The results are useful for the design of the drive system. ;

• Journal of International Academy of Physical Therapy Research
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• v.10 no.2
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• pp.1763-1767
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• 2019

Background: Although previous researches have developed interventions for neck problems, headache, and temporomandibular disorder in patients with forward head posture (FHP), changes in masticatory muscle tone or stiffness as FHP worsening have not been investigated. Objective: To examine changes in masticatory muscle tone and stiffness through craniovertebral angle (CVA). Design: Cross sectional study Methods: The subjects were 21 healthy males with normal head posture. Three CVA were established for posture measurement in which the bilateral anterior temporal and masseter muscles were measured during the subjects maintained a series of postures. Results: The Right masseter muscle significantly increased in stiffness with advancing FHP (p < 0.05). No significant changes were observed in the muscle tone or stiffness of any other masticatory muscles, and no significant differences were found in bilateral masticatory muscle tone or stiffness in each measurement posture. Conclusions: This study suggests that the increased stiffness of the right masseter muscle as the FHP worsened requires consideration in physical therapy assessment and intervention.

• 한국항공우주법학회:학술대회논문집
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• 2008.05a
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• pp.165-182
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• 2008

The purpose of this study is to review the changes in the aviation safety management system, how that system has evolved and what forces caused these changes to take place. Also included is an examination of the development process of the aviation safety management system in view of the new institutionalism, identifying the patterns of change. Based on the results of this study, I propose policy methods to design a desirable civil aviation safety system with a view toward raising the safety standards in the Korean civil aviation community. The major analysis variables are as follows: first, aviation accidents caused by external factors and international standards as independent variables; second, environmental changes and political processes affecting aviation safety management system as major mediating variables; and third, the aviation safety management legal system, the aviation safety management organizations and an expert participation system as dependent variables. The institutional changes and continuance of the aviation safety management system show that when specific circumstances arise, the continuance lasts depending on the path dependency, and in a certain circumstance, when immanent changing factors reach a critical point, the system suddenly changes by a punctuated equilibrium, which are all included in this study.

• Journal of Distribution Science
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• v.14 no.9
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• pp.31-45
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• 2016

Purpose - This study develops a simulation model that looks at the dynamics between social capital and business performance in strategic networks to understand their behaviors in relation to each other, and to suggest dynamic relationship strategies. Research design, data, and methodology - Based on existing literature, this study identifies the complex causal loop diagram on social capital and business performance in strategic networks, and converts them into a simulation model for observing how the changes in business environment and relationship dependency affect social capital and business performance. Results - The simulation results showed that, first, the formation in social capital and business performance of networks with low relationship dependency was less affected by the changes in business environment. Second, the formation in social capital and business performance of networks with high relationship dependency was negatively impacted by the changes in business environment. In other words, higher relationship dependency strengthened the impact of changes in business environment on business performance. Conclusions - Thus, this study confirmed that in strategic networks, the changes in business environment and the degree of relationship dependency dynamically affect business performance, and that relationship dependency mediates the degree in which changes in the business environment affect business performance. The results of the simulations were further verified through actual business cases.

• Asia-Pacific Journal of Business
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• v.13 no.2
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• pp.23-37
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• 2022

Purpose - The purpose of this paper is to analyze the dynamic factors of the daily FX implied volatility based on the fractional integration methods focusing on long memory feature and structural changes. Design/methodology/approach - This paper uses the daily FX implied volatility data of the EUR-USD and the JPY-USD exchange rates. For the fractional integration analysis, this paper first applies the basic ARFIMA-FIGARCH model and the Local Whittle method to explore the long memory feature in the implied volatility series. Then, this paper employs the Adaptive-ARFIMA-Adaptive-FIGARCH model with a flexible Fourier form to allow for the structural changes with the long memory feature in the implied volatility series. Findings - This paper finds statistical evidence of the long memory feature in the first two moments of the implied volatility series. And, this paper shows that the structural changes appear to be an important factor and that neglecting the structural changes may lead to an upward bias in the long memory feature of the implied volatility series. Research implications or Originality - The implied volatility has widely been believed to be the market's best forecast regarding the future volatility in FX markets, and modeling the evolution of the implied volatility is quite important as it has clear implications for the behavior of the exchange rates in FX markets. The Adaptive-ARFIMA-Adaptive-FIGARCH model could be an excellent description for the FX implied volatility series

• International conference on construction engineering and project management
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• 2007.03a
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• pp.540-553
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• 2007

Strategic management of changes is very significant for all types of construction projects. Project management teams must have the ability to respond to changes effectively in order to minimize their adverse impact on the project. The study focuses on the causes, their frequent effects and effective controls for changes in educational building projects. To achieve the study objectives, a questionnaire survey was carried out to collect relevant information. Through the literature review, 53 causes, 16 effects and 30 potential controls for change orders were identified. These provided the basis for the formulation of the questionnaire. Responses from 92 professionals who were involved in the educational projects in Singapore were analyzed. They included 28 developers, 33 consultants and 31 contractors. From the survey findings, the most important causes of changes were identified. The study revealed the most frequent effects and most effective controls for each cause of change order. Arising therefrom, a comprehensive tabulation of the 53 causes and their frequent effects and effective controls was also developed. A timeline for implementing the controls was developed through in-depth interviews with the professionals. The study would assist building professionals in taking proactive measures for reducing change orders for educational buildings; furthermore, the timeline would also be helpful for them to implement controlling strategies at the appropriate time. Recommendations were suggested based on the research findings.

• The Journal of Industrial Distribution & Business
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• v.14 no.6
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• pp.27-35
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• 2023

Purpose: Convergence and social ripple effects caused by the Fourth Industrial Revolution, which encompasses new technologies in various fields, will have a great impact on the beauty industry structure and market economy. This review reviewed the literature on the changes in the employment environment of the Korean beauty industry due to the 4th industrial revolution and the countermeasures of the beauty industry accordingly. Research design, data and methodology: Using the October 2022 PRISMA flowchart, it is a review of changes in the employment environment of the beauty industry, the need for human resource management of beauty workers, and the employment environment to be applied to the beauty industry in the future. Results: Changes in the employment environment in the era of the 4th Industrial Revolution, the current state of the beauty industry, and reviews on beauty industry workers were collected, and a direction for training beauty industry workers was presented. Conclusions: This study presented the direction of the beauty industry in preparation for changes in the employment environment of the 4th industrial revolution and suggested that research is needed to actively establish human resource management (HRM) to overcome the problem of fostering talent in the beauty industry.

• The Journal of Information Systems
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• v.32 no.3
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• pp.117-132
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• 2023

Purpose The purpose of this study is to analyze the impact of policy changes in Busan's local currency, Dong Baek Jeon, on the use of Dong Baek Jeon. In particular, this study tried to investigate consumption changes due to changes in local currency policy depending on the region, industry, and consumer characteristics. Design/methodology/approach This study used the transaction data of Dong Baek Jeon franchise for analysis. Specifically, the data from January 2022 to December 2022 were used to analyze the current status of the use of Dong Baek Jeon and changes in consumption before and after policy changes. Findings As a result of the analysis, the consumption of Dong Baek Jeon tended to be concentrated in specific regions, industries, and ages. In most regions and ages, the top consumption industries were similar. The use of Dong Baek Jeon showed a clear change in the pattern of use depending on policy changes. Specifically, when the benefits were revised downward, the use of Dong Baek Jeon decreased, and when it was revised upward, it increased. Depending on the policy change, the rate of increase and decrease by region and consumer characteristics was relatively similar, but it was confirmed that there was a difference in the rate of increase and decrease depending on the industry.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.11-18
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• 2011

A Shock absorber is one of the most important components in vehicle suspension systems. In general, many repeated analyses are required for the design of a shock absorber to satisfy the suspension characteristics of a specific automobile, like fluid flow analysis and mechanical analysis. The purpose of this study is to develop a fast design tool for shock absorber designers. One of the efficient solutions for this can be an empirical design method considering phenomenological effects from the shock absorber design variables. In order to extract the shock absorber's experimental characteristics, we used Taguchi method. This method showed that which design variables have major effects for the shock absorber's damping characteristics. This empirical design method also showed the direction of the design changes to satisfy the designer's intension.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.279-284
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• 2016

Finite element analysis along with DOE scheme has been performed to obtain robust design of crankshaft assembly. This study focused on obtaining optimized fillet radius of crankshaft mainly by statistical approach. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Changes of design factors and noise factor may influence the durability of crankshaft system. General two stages of robust design may enhance the durability of crankshaft model. Increasing crank arm thickness was adopted as a shrink step and change of fillet radius was used as a shift step. By combining these two steps, the stress concentration at the fillet area is reduced and adequate fillet radius is determined for the robust design of crankshaft.