• 대한수학회보
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• 제52권6호
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• pp.1973-2000
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• 2015

In this study, we present a multidimensional open system for valveless pumping (VP). This system consists of an elastic tube connected to two open tanks filled with a fluid under gravity. The two-dimensional elastic tube model is constructed based on the immersed boundary method, and the tank model is governed by a system of ordinary differential equations based on the work-energy principle. The flows into and out of the elastic tube are modeled in terms of the source/sink patches inside the tube. The fluid dynamics of this system is generated by the periodic compress-and-release action applied to an asymmetric region of the elastic tube. We have developed an algorithm to couple these partial differential equations and ordinary differential equations using the pressure-flow relationship and the linearity of the discretized Navier-Stokes equations. We have observed the most important feature of VP, namely, the existence of a unidirectional net flow in the system. Our computations are focused on the factors that strongly influence the occurrence of unidirectional flows, for example, the frequency, compression duration, and location of pumping. Based on these investigations, some case studies are performed to observe the details of the ow features.

• Applied Biological Chemistry
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• 제32권1호
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• pp.57-63
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• 1989

담배저장해충은 숙성된 엽연초에 가장 심각한 해를 끼치는 것으로 알려져 있다. 이 해충의 성유인 물질들 중에서 serricornin이 가장 강한 생리활성을 보여주고 다른 유인물질들은 교접시 이것에 대한 보조역할을 한다. 분광학적인 증거와 합성에 관한 연구로부터 이 화합물의 구조는 (4S,6S,7S)-4,6-dimethyl-7-hydroxynonan-3-one임이 밝혀졌다. 담배저장 해충으로부터 얻어진 성유인 물질들은 모두 polyketide 생합성의 과정에서 생성된다고 제안되었다. 두 가지 nonasymmetric 합성과 열가지 asymmetric 합성이 상세하게 고찰되었다.

• 응용통계연구
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• 제29권1호
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• pp.221-230
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• 2016

주식시장 거래에서 기록되는 고빈도 자료를 사용하여 주식 수익률에 대한 변동성을 분석하였다. 변동성을 설명할 수 있는 한 요소로 주식거래에서 불규칙한 간격으로 발생하는 가격 듀레이션을 생각할 수 있는데, 실제 자료에 ACD 모형을 사용하여 듀레이션을 추정해 보았고, ACD-GARCH 모형을 사용하여 주식 수익률과 변동성에 미치는 듀레이션의 영향을 살펴보았다. 이 과정에서 ACD 모형 추정에는 ML과 EF 방법을 적용하였고, ACD-GARCH 모형에는 이중-분계점(double-threshold)을 추가하여 평균수익률의 비대칭성 및 변동성의 비대칭성을 동시에 분석해 보았다.

• 복식문화연구
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• 제8권1호
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• pp.102-114
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• 2000

The works of the Futurism were developed along with manifestos and statement in publishing. Futurist aesthetic and ideological agenda on futurist fashion displayed in manifestos on clothes. Futurist fashion propagated in consummate Futurist style through the written manifesto. The Futurists anticipated much of modern fashion phenomenon. In Futurist Men's Clothing, men's clothing is aggressive, agile, dynamic, simple and comfortable, hygienic, gay, luminous, volatile, asymmetric and variable. In Futurist Manifesto on Woman's Clothing, woman is now a principal agent of revolt, a walking synthesis of the audacious, performance-oriented aesthetic of the futurist universe. For Futurist woman's clothing they claimed ingenuity, daring, and economy. The Futurist Manifesto of Italian Hat was continued with their provocative style and radical ambition. Their innovation will rescue a lagging Italian expert and restore the Italian male to his former Iatin Vigor. Speed, dynamic, utility, and funtionality are the main characters. In Futurist Manifesto of Italian Cravat, Futurist cravat is called Anti-cravatta, which is anti-traditional style and made of unconventional materials. In general, the Futurist argued for clothes that promoted simple and functionality. These Futurist fashion project were invention of the new style, avant-garde style, in daily wear and were realized for the renewal of taste in clothing design as a modernizing factors.

• 대한기계학회논문집A
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• 제20권12호
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• pp.3909-3916
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• 1996

Magnetic bearing is the machine element that supports the shaft without mechanical contact using the magnetic force induced by permanent magnet of electromagnet. Active magnetic bearing system is composed of sensor, controller, power amplifier, and electromagnet. If all the elements were dieal, shaft position could be controlled to sensor resolution, Because each elements inreal system have mechanical and electricla losses and nonlinearity, it is impossible to attain the desired performance using general control algorithm. So far it has been studied on improvement of the control algorithm of the electric characteristics of each elements. Another factors to affect shaft behavior are the manufacturing errors due to machine work, and assembling errors due to accumulate manufacturing errors of the radial magnetic bearing. This paper describes that the shaft behavior due to accumulate manufacturing errors and asymmetric bolting. This paper describes that the shaft behavior due to assembling errors of the radial bearings donot affect the rotaitonal accuracy of the shaft. But when the amplitude of the assembling errors increasees over the certain value, the bearing can not support the shaft properly.

• Advances in materials Research
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• 제4권2호
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• pp.113-132
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• 2015

The phenomena of high-voltage polarization and conductivity in oriented vinylidenefluoride and tetrafluoroethylene copolymer films have been investigated. It was shown that under certain electric fields, injection of carriers from the material of electrodes appears The barrier for holes injection in the copolymer was found to be lower than that for electrons. It results in more effective screening of the external field near the anode than near cathode. Electrones, ejected from cathode, creating negative charge by trapping on the surface. It is shown that the electrons injected from cathodes create a negative homocharge on the copolymer surface and then become captured on the surface shallow traps. Their nature has been studied by the x-ray photoelectron spectroscopy. It was shown that these traps may consist of chemical defects in the form of new functional groups formed by reactions of surface macromolecules with sputtered atoms of aluminum. The asymmetric shape of hysteresis curves was explained by the difference in mobility of injected holes and electrons. These factors caused appearance of "non-closed" hysteresis curves for fluorine-containing polymer ferroelectrics. Hysteresis phenomena observed at low electric fields (below coercive ones) are to associate with the behavior of the domains localized in the ordered regions formed during secondary crystallization of copolymers.

• 유통과학연구
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• 제19권1호
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• pp.27-35
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• 2021

Purpose: This study is to investigate the effect of managerial ownership level in distribution and service companies on the stock price crash. The managerial ownership level affects the firm's information disclosure policy. If managers conceal or withholds business-related unfavorable factors over a long period, the firm's stock price is likely to plummet. In a similar vein, management's equity affects information opacity, and information asymmetry affects stock price collapse. Research design, data, and methodology: A regression analysis is conducted using the data on companies listed on the Korea Composite Stock Price Index (KOSPI) between 2012-2017 to examine the effect of the managerial ownership level on stock price crash risks. Results: Logistic and regression results indicate that the stock price crash risk was reduced as managerial ownership levels are increased. The managerial ownership level has a significant negative coefficient on stock price crash risk, negative conditional return skewness of firm-specific weekly return distribution, and asymmetric volatility between positive and negative price-to-earnings ratios. Conclusions: As the ownership and management align, the likeliness of withholding business-related information is reduced. This study's results imply that the stock price crash risk reduces as the managerial ownership level increases because shareholder and manager interests coincide, thereby reducing information asymmetry.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.1-9
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• 2021

This paper investigates the impact of the domestic and global outbreak of the coronavirus (COVID-19) pandemic on the trading size of the Malaysian stock (MS) market. The theoretical model posits that stock markets are affected by their response to disasters and events that arise in the international or local environments, as well as to several financial factors such as stock volatility and spread bid-ask prices. Using daily time-series data from 27 January to 12 May 2020, this paper utilizes the traditional Augmented Dickey and Fuller (ADF) technique and Zivot and Andrews with structural break' procedures for a stationarity test analysis, while the autoregressive distributed lag (ARDL) method is applied according to the trading size of the MS market model. The analysis considered almost all 789 listed companies investing in the main stock market of Malaysia. The results confirmed our hypotheses that both the daily growth in the active domestic and global cases of coronavirus (COVID-19) has significant negative effects on the daily trading size of the stock market in Malaysia. Although the COVID-19 has a negative effect on the Malaysian stock market, the findings of this study suggest that the COVID-19 pandemic may have an asymmetric effect on the market.

• 유통과학연구
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• 제20권3호
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• pp.71-82
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• 2022

Purpose: This study aims to not only measure the elderly welfare supply index but investigate spatial patterns and determinants of local elderly welfare services in South Korea. Research design, data, and methodology: The index for local elderly welfare services is measured by employing standardized scores for critical variables related to elderly welfare. The present study utilized the GIS technique and Moran's I index to examine spatial patterns of elderly welfare services. The determinants of local elderly welfare service are analyzed by a series of regression models using R. Results: Spatial imbalance and asymmetric distribution were serious in the supply of elderly welfare service. It was also confirmed that the factors affecting the level of welfare services for the elderly vary depending on the type of service. In particular, the higher the proportion of the elderly population and the social welfare budget, the lower the level of welfare services for the elderly. Conclusions: Given the circumstance of spatial mismatch between supply and demand for elderly welfare services, it is necessary to consider and provide policy tactics about how the economic benefits and welfare budgets generated in the region can contribute to strengthening the welfare service system for the elderly.

• 아태비즈니스연구
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• 제13권2호
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• pp.197-207
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• 2022

Purpose - This study reestablished the concept of mixed emotions experienced in online and offline shopping environments, and structuralized emotional responses which manifest mixed emotions in each channel, and developed a method of measuring overall mixed emotions in consideration of the asymmetry of emotions. Design/methodology/approach - This study conducted a focus in-depth interview based on phenomenological research and exploratory preliminary survey using questionnaires. In addition, a survey was conducted as a quantitative survey. Findings - Qualitative and quantitative researches were conducted to derive major emotional responses items which manifest mixed emotions in online and offline shopping environments and determine differential emotional structure in each channel. As a result, it was confirmed that mixed emotions consisted of 5 factors in each channel and 21 emotional responses. In addition, a method of measuring overall mixed emotions considering the asymmetric of emotions was developed to prove the difference in behavioral responses. Research implications or Originality - This study is meaningful in that it helps companies efficiently manage and understand customer responses to their products by classifying and systemizing the emotional responses experienced by consumers in online and offline purchase and consumption situations according to the purchase environment.