• International Area Studies Review
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• v.15 no.3
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• pp.55-76
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• 2011

In this paper, we estimate a model that incorporates key features of business cycles, co-movement among economic variables and switching between regimes of expansion and recession, to aggregate quarterly data for the NAFTA region. Two common factors reflecting the permanent and transitory components of the business cycle in the region, along with the turning points from one regime to the other, were extracted from the data by using the Kalman filter and maximum likelihood estimation approach of Kim (1994). Estimation results confirm that a typical aspect of business cycles are also observed (i.e., recessions are steeper and shorter than recoveries) in the region, and that both co-movement and that regime switching are found to be important features of the business cycle. The two common factors produce sensible representations of the trend and cycle, and the estimated turning points are in line with independently determined chronologies. It also turns out that the degree of synchronization between the NAFTA region and Korea, has significantly increased since the entry into force of the NAFTA.

• Journal of Korean Society of Steel Construction
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• v.26 no.3
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• pp.177-189
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• 2014

When floor vibration problems occur in existing buildings, TMD (tuned mass damper) can be a viable alternative to resolving the problem. Only when TMD has been exactly tuned to the natural frequency of the floor, it can control the vibration as intended in design. However, TMD gets inefficient in the situation where the natural frequency changes as a result of the uncontrollable variation of the floor mass weight. This physical phenomenon is often called as TMD-off-tuning. This study proposes asymmetric TMD for enhancing the robustness of floor vibration control against uncertain natural frequencies. The proposed TMD features two asymmetric linear springs such that the floor vibrational energy can be dissipated through both the translational and rotational motion. An easy-to-use graphical optimization method was developed in this study. The asymmetric TMD proposed outperformed in vibration control by 28% compared to that of conventional TMD. The robustness of asymmetric TMD of this study was two times higher than that of conventional TMD.

• Korea Petroleum Association Journal
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• no.10 s.200
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• pp.98-101
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• 1997

태국을 비롯한 동남아 국가들은 90년대 후반 이후 경제성장 둔화, 경상수지 악화, 금융제도 불안 등으로 기초경제여건이 취약해진 가운데 통화의 고평가 심리가 팽배해지면서 지난 7월 통화가치가 급락하는 외환위기를 겪었음 이번의 외환위기는 금융규제완화 및 자본 자유화로 금융의 범세계화가 진전되면서 한 국가의 외환위기가 인접국으로 신속히 확산되는 동조화 현상 (Spill-over effect)이 보편화되고 있음을 보여주었음. 그러나 우리나라의 경우 기초경제여건, 시장개방도, 원화의 국제화 정도 등을 감안할 때 최근의 동남아 외환위기가 국내로 파급될 가능성은 없는 것으로 평가됨. 외환위기를 예방하기 위하여는 국제수지 등 기초경제여건의 개선과 함께 탄력적인 환율운용, 적정 외환보유액의 확보 및 중앙은행간 협력업체의 강화 등을 통해 급격한 외화유출입에 대한 대응능력을 높여 나가야 할 것임

• Proceedings of the Korean Society of Crop Science Conference
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• 1995.05a
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• pp.12-13
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• 1995

• Journal of Teachers' Pension
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• v.3
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• pp.255-278
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• 2018

본 연구는 사학연금에서 연기연금재도의 도입 필요성을 검토하고 특히 도입 시 적용할 가산율 설정 등 구체적인 도입방안을 제시하고자 하였다. 사학연금에서 연기연금제도는 수급자의 근로유인과 활동적 노년의 진작을 위해서 필요하다. 이는 또한 국민연금과 직역연금이 동조화되고 있는 현 추세와도 일치한다. 이 연구는 또한 국민연금의 연기연금제도를 참고하여 보험수리적 중립성에 입각한 공정가산율을 산출하였다. 이 방식에 따르면 사학연금 연기연금제도의 핵심제도인 공정가산율은 6.2%로 나타났다.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.151-160
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• 2021

The purpose of this study is to classify online shopping malls into total transaction amount and transaction amount by product, and compare them to find synchronism. The data used in this study were collected from KOSIS for Food Services, Home Appliances·Electronics·Communication devices, Food & Beverages, House_Goods, Clothing, Computers & Peripheral Devices. The analysis period is a total of 44 monthly data from January 2017 to August 2020. In descriptive statistics, variability is relatively very stable in the case of food service, but is large in the case of clothing. In the correlation analysis, the total transaction amount shows a certain level of correlation with each product. In the analysis of the increase rate, Food Service increased by 1,039%, Home Appliances·Electronics·Communication devices increased by 325%, Food & Beverages increased by 296% and House Goods by 250%, but Clothing decreased slightly to 92.56%. In the Scatter Charts analysis, the distribution of Total transaction amount & House Goods, Total transaction amount & Home Appliances·Electronics·Communication devices is generally upward, showing a high level of synchronization. Due to Corona 19, we will have to continue our efforts to provide speed, stability, convenience and various services in preparation for the increase in transaction volume of online shopping malls.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.117-129
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• 2015

As the Internet becomes ubiquitous, a large volume of information is posted on the Internet with exponential growth every day. Accordingly, it is not unusual that investors in stock markets gather and compile firm-specific or market-wide information through online searches. Importantly, it becomes easier for investors to acquire value-relevant information for their investment decision with the help of powerful search tools on the Internet. Our study examines whether or not the Internet helps investors assess a firm's value better by using firm-level data over long periods spanning from January 2004 to December 2013. To this end, we construct weekly-based search volume for information technology (IT) services firms on the Internet. We limit our focus to IT firms since they are often equipped with intangible assets and relatively less recognized to the public which makes them hard-to measure. To obtain the information on those firms, investors are more likely to consult the Internet and use the information to appreciate the firms more accurately and eventually improve their investment decisions. Prior studies have shown that changes in search volumes can reflect the various aspects of the complex human behaviors and forecast near-term values of economic indicators, including automobile sales, unemployment claims, and etc. Moreover, search volume of firm names or stock ticker symbols has been used as a direct proxy of individual investors' attention in financial markets since, different from indirect measures such as turnover and extreme returns, they can reveal and quantify the interest of investors in an objective way. Following this line of research, this study aims to gauge whether the information retrieved from the Internet is value relevant in assessing a firm. We also use search volume for analysis but, distinguished from prior studies, explore its impact on return comovements with market returns. Given that a firm's returns tend to comove with market returns excessively when investors are less informed about the firm, we empirically test the value of information by examining the association between Internet searches and the extent to which a firm's returns comove. Our results show that Internet searches are negatively associated with return comovements as expected. When sample is split by the size of firms, the impact of Internet searches on return comovements is shown to be greater for large firms than small ones. Interestingly, we find a greater impact of Internet searches on return comovements for years from 2009 to 2013 than earlier years possibly due to more aggressive and informative exploit of Internet searches in obtaining financial information. We also complement our analyses by examining the association between return volatility and Internet search volumes. If Internet searches capture investors' attention associated with a change in firm-specific fundamentals such as new product releases, stock splits and so on, a firm's return volatility is likely to increase while search results can provide value-relevant information to investors. Our results suggest that in general, an increase in the volume of Internet searches is not positively associated with return volatility. However, we find a positive association between Internet searches and return volatility when the sample is limited to larger firms. A stronger result from larger firms implies that investors still pay less attention to the information obtained from Internet searches for small firms while the information is value relevant in assessing stock values. However, we do find any systematic differences in the magnitude of Internet searches impact on return volatility by time periods. Taken together, our results shed new light on the value of information searched from the Internet in assessing stock values. Given the informational role of the Internet in stock markets, we believe the results would guide investors to exploit Internet search tools to be better informed, as a result improving their investment decisions.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.5
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• pp.151-168
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• 2022

Nowadays companies are required to achieve social goals beyond maximizing shareholder profits. Accordingly, it is important to pursue both the economic and social goals of a company at the same time. Thus the importance of hybrid organizations is increasing theoretically and practically. In particular, since hybrid organizations essentially have the complexity of pursuing both economic and social purposes, the institutional demands of various stakeholders surrounding hybrid organizations are also conflicting. Several previous studies have considered how hybrid organizations respond to these conflicting institutional demands, but most studies are limited to studying at a specific point in time. As a result, there was a limit to analyzing the dynamics in response to conflicting institutional demands as the hybrid organization expanded its business. This study predicted that the hybrid organization would take selective coupling with conflicting institutional demands and that the process of responding to institutional demands would change according to the organization's growth. In this study, we had a case study about Noul and Enuma, social ventures that operate relatively advanced business models with outstanding results in innovation and technology. As a result, social ventures show a selective coupling for conflicting institutional demands, and the selective coupling process changes as their business model are advanced. Specifically, in the early stages of the business, it appears to respond to economic and social demands at the same time with a single business model. When the business is advanced, two or more business models are operated, some of which respond to economic needs and some of which respond to social needs. In the early stages of business, social ventures respond to economic and social demands with a single business model to gain legitimacy and survive in the institutional demands. But when they enter the business growth period, they try to separate business models which respond to economic and social values because they pursue sustainable growth and challenge large-scale missions. Overall, this study attempted to contribute to an in-depth understanding of hybrid organizations by identifying that the method of responding to conflicting institutional demands varies depending on the growth process of social ventures.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.5
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• pp.29-36
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• 2012

3-D linear acoustic analysis has been performed to elucidate damping characteristics of large Helmholtz acoustic cavities in FASTRAC thrust chamber. Acoustic impedance concept has been introduced to quantify combustion stabilization capacity. For a given acoustic cavity, sonic velocity in the cavity to achieve an optimal tuning has been determined and satisfactory agreement with the previous results has been obtained. Feasible estimation of sonic velocity in the acoustic cavity has been devised. Results show similar trends without significant deviations, which can be used in the procedure of design and verification of acoustic cavity. From the satisfactory results, investigation of other thrust chambers with acoustic cavities which have shown combustion instabilities will be done as future works.

• The Korean Journal of Applied Statistics
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• v.21 no.2
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• pp.221-231
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• 2008

This study attempts to perform the statistical tests for the comovement of the stock prices between Korea and U.S. by using the weekly data instead of the usual daily data. The restoring pattern, from the short-run disequilibrium to the long-run equilibrium point, is also carefully estimated if the long-run relationships exist between the stock prices. The cointegrating relations between the stock prices appear to begin to hold during the period of the financial crisis. It is found to be consistently estimated that the equilibrium error is slowly eliminated till the end of the financial crisis, while quickly removed after the period.