• Communications for Statistical Applications and Methods
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• v.27 no.6
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• pp.649-673
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• 2020

This paper makes a theoretical contribution by providing clear and detailed derivation of economic agents' decision problems including elastic labor supply in Gertler's overlapping generation (OLG) model. We apply the model to the Korean economy by calibration based on Korean economic data. It also analyzes the impact of current social issues such as aging and extension of retirement age, on the Korean economy in a long-run equilibrium. Subsequently, we also discuss the implications of the analysis. Aging has prolonged the period of retirement; therefore, population structure changes by the increase in the proportion of retirees, the total consumption-to-GDP ratio decreases, and capital stock increases due to reduced propensity to consume out of wealth in preparation for an individual's retirement life. The implementation of retirement age extension increases the proportion of retirees relatively less and alleviates fluctuations in labor supply and the share of financial assets for both economic agents. However, the decrements in consumption-to-GDP ratio is larger than before, and this leads to a larger rise in the capital stock compared to when there is only an aging effect.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.69-76
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• 2000

Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectiories.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.433-439
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• 2000

Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption and small size. To design a MR damper that has a large maximum dissipating torque and a low damping coefficient, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectories.

• Nutrition Research and Practice
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• v.12 no.2
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• pp.143-148
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• 2018

BACKGROUND/OBJECTIVES: Average intake of calcium among college students is below the recommended intake, and knowledge surrounding the attitudinal and behavioral factors that influence milk and dairy intake, a primary food source of calcium, is limited. The purpose of this study was to evaluate college students' attitudes and behaviors concerning milk and dairy consumption and their association with calcium intake. SUBJECTS/METHODS: Participants were 1,730 undergraduate students who completed an online survey (SurveyMonkey) as part of baseline data collection for a social marketing dairy campaign. The online survey assessed attitudes and behaviors concerning milk and dairy intake, and calcium intake. Questions about milk- and dairy-related attitudes and behaviors were grouped into 14 factors using factor analysis. Predictors of calcium intake were then evaluated. RESULTS: Median calcium intake across all participants was 928.6 mg/day, with males consuming higher calcium intakes than females (P < 0.001). Adjusted for gender, calcium intakes were most strongly (and positively) correlated with associating milk with specific eating occasions and availability (i.e., storing calcium-rich foods in one's dorm or apartment) (both P < 0.001). Other correlates of calcium intake included: positive-viewing milk as healthy (P = 0.039), having family members who drink milk) (P = 0.039), and taking calcium supplements (P = 0.056); and negative-parent rules concerning milk (P = 0.031) and viewing milk in dining halls negatively (P = 0.05). CONCLUSIONS: Calcium intakes among college students enrolled in the current study was below the recommended dietary allowance of 1,000 mg/day, reinforcing the need for dietary interventions in this target population, especially females. Practitioners and researchers should consider the factors found here to impact calcium intake, particularly associating milk with specific eating occasions (e.g., milk with breakfast) and having calcium-rich foods available in the dorm room or apartment, as intervention strategies in future efforts aimed at promoting milk and dairy foods and beverages for improved calcium intake in college students.

• Journal of Information Technology Applications and Management
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• v.30 no.1
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• pp.115-126
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• 2023

In various fields such as art, design, music, film, sports, games, and fashion, NFTs (Non-Fungible Tokens) are creating new economic value through trading platforms dedicated to NFT art and content. In this article, I analyze the current state of blockchain technology and NFT art content in the context of an expanding market for blockchain-based NFT art content in the metaverse. I also propose several tasks based on the economic and industrial logic of technological innovation. The first task proposed is to integrate cultural arts on blockchain, metaverse, and NFT platforms through digital innovation, instead of separating or distinguishing between creative production and consumption. Before the COVID-19 pandemic, there was a clear separation between creators and consumers. However, with the rise of Web 3.0 platforms, any user can now create and own their own content. Therefore, it is important to promote a collaborative and integrated approach to cultural arts production and consumption in the blockchain and metaverse ecosystem. The second task proposed is to align the legal framework with blockchain-based technological innovation. The enactment and revision of relevant laws should focus on promoting the development of the NFT trading platform ecosystem, rather than merely regulating it for user protection. As blockchain-based technology continues to evolve, it is important that legal systems adapt to support and promote innovation in the space. This shift in focus can help create a more conducive environment for the growth of blockchain-based NFT platforms. The third task proposed is to integrate education on digital arts, including metaverse and NFT art contents, into the current curriculum. This education should focus on convergence and consilience, rather than merely mixing together humanities, technology, and arts. By integrating digital arts education into the curriculum, students can gain a more comprehensive understanding of the potential of blockchain-based technologies and NFT art. This article examines the digital technological innovation such as blockchain, metaverse, and NFT from an economic and industrial point of view. As a limitation of this research, the critical mind such as philosophical thinking or social criticism on technological innovation is left as a future task.

• ETRI Journal
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• v.35 no.5
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• pp.767-774
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• 2013

In this paper, a novel parallel Viterbi decoding scheme is proposed to decrease the decoding latency and power consumption for the software-defined radio (SDR) system. It implements a divide-and-conquer approach by first dividing a block into a series of subblocks, then performing independent Viterbi decoding for each subsequence, and finally merging the surviving subpaths into the final path. Moreover, a network-on-chip-based SDR platform is used to evaluate the performance of the proposed parallel Viterbi decoding scheme. The experiment results show that our scheme can speed up the Viterbi decoding process without increasing the BER, and it performs better than the current state-of-the-art methods.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.103-110
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• 2020

In this study, the design and operating strategy of DC home grid with PV, battery, and ultracapacitor have been discussed, The proposed sizing method can find the optimum size of the battery and PV which can reduce yearly utility energy consumption, whereas the control scheme can maintain the DC-bus voltage level of the DC home grid under different operating conditions, where day or night time operation, load and PV power levels, and the maximum current and state-of-charge of batter are considered. In addition, a supervisory power management strategy has been suggested, and its validity has been verified by HILS (hardware in-the-loop simulation) results.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.674-682
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• 2017

This paper presents an optimal initial firing angle control based on the energy consumption and regenerative energy of a parallel multi-pulse thyristor dual converter for urban railway power substations. To prevent short circuiting the thyristor dual converter, a hysteresis band for maintaining a zero-current discontinuous section (ZCDS) is essential during mode changes. During conversion from the ZCDS to forward or reverse mode, the DC trolley voltage can be stabilized by selecting the optimal initial firing angle without an overshoot and slow response. However, the optimal initial firing angle is different depending on the line impedance of each converter. Therefore, the control algorithm for tracking the optimal initial firing angle is proposed to eliminate the overshoot and slow response of DC trolley voltage. Simulations and experiments show that the proposed algorithm yields the fastest DC voltage control performance in the transient state by tracking the optimal firing angle.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1341-1348
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• 2009

Electrocatalytic oxidation of two anti-inflammatory drugs (Mefenamic acid and Indomethacin) was investigated on a cobalt hydroxide modified glassy carbon (CHM-GC) electrode in alkaline solution. The process of oxidation and its kinetics were established by using cyclic voltammetry and chronoamperometry techniques as well as steady state polarization measurements. Voltammetric studies indicated that in the presence of under study drugs, the anodic peak current of low-valence cobalt species increased, followed by a decrease in the corresponding cathodic current. This result indicates that the drugs were oxidized via cobalt hydroxide species immobilized on the electrode surface via an E$\acute{C}$ mechanism. A mechanism based on the electrochemical generation of Co (IV) active sites and their subsequent consumption by the drugs in question was also investigated. The constants rate of the catalytic oxidation of the drugs and the electron-transfer coefficients reported.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.7
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• pp.1139-1152
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• 1997

Clothing consumption expenditure (UX) data of Korean consumers during the period of 1965 to 1993 were analyzed by time series analysis technique. According to the results of regression analysis, current income and UX of the year before showed most significant influences on the current UX. This means that the absolute and permanent income hypotheses can be accepted in case of clothing expenditures. However the effect of income decreased as the economy developed. The relative price of clothing had weak or no influence on clothing expenditures. It was also found out that CSX of the year before, the change of income, relative price of clothing ware the factors that affected clothing expenditures. From the estimation of Houthakker-Taylor state adjustment model, a negative stock coefficient was obtained. That is, clothing is subject to an inventor effect and Korean consumers regard clothing as one of the durable goods. To define whether clothing is a "luxury" or a "necessity", income and relative price elasticity of clothing expenditures were estimated. Income elasticity of clothing is slightly below 1.0 in case of national aggregate expenditures, and slightly above 1.0 in case of urban consumers' expenditures. Income elasticity has declined over time. Meanwhile the coefficient of price elasticity is not significant, indicating that the relative price of clothing have little connection with clothing expenditure.lothing expenditure.