• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.30-38
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• 2012

This paper discusses a clearance pricing on daily perishable products considering a reference price of consumers. The daily perishable products are sometimes sold at a discount price before closing time to stimulate demand when the number of unsold products is more than initially envisioned. The discount pricing results both in an increase of the revenue of the day and in a decrease of the disposal cost. The discounting, however, also declines a reference price of consumers which is a mental price and serves as an anchor price to judge if a current sales price is loss or gain for the consumers. An excess discounting decreases the demand for the products sold at a regular price in the future and diminishes long-term profit. This study conducts a mathematical analysis on the clearance pricing problem for a single period with stochastic variations both on demand and on the inventory level at clearance time. The expected profit function especially depends on the response of consumers to the clearing price against their reference prices. A procedure is proposed to derive an optimal clearance price when consumers are loss-neutral. A sufficient condition is shown to obtain an optimal price for loss-averse and loss-seeking consumers by an analogous procedure.

• Journal of Korean Society of Rural Planning
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• v.25 no.3
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• pp.67-75
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• 2019

Agricultural production facilities that have been established to support improving food production, farm income, and reduction of farming time have remarkable achievements as value-neutral devices or infrastructures, but recently they are pointed out as a factor that hinders landscape by changing the contextual values of rural area. Despite this timelessness, research on the landscape design of agricultural production facilities has not been conducted until now. Based on these research necessities, this study aims to improve the process of reviewing the landscape of agricultural production facilities by analyzing the impact of activities, policies, plans. The results of this study are as follows. First, the analysis of the literature and the related data were carried out. This presents the structural limitations of why landscape review is difficult in the process of reviewing plans and the limitations of current landscape laws, deliberations, and plans. The process of reviewing the plan has formed a functionally oriented closed network, and the government policy does not properly control the landscape design of agricultural production facilities. From the viewpoint of the study, results can be used as basic data for the study of the lack of agricultural production facilities and landscape.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.86-88
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• 2018

The three level(3L) neutral point clamped (NPC) voltage source converter (VSC) topology is widely used for grid interface in high power wind energy due to its superior performance as compared to the two level(2L) VS. However, one of the major drawbacks of this topology is the unequal dispersion of loss and therefore the junction temperature among the power devices. The 3L ANPC topology derived from the NPC topology was proposed to resolve this drawback of unequal loss profile of 3L NPC. The 3L ANPC can work under various switching strategies. In this paper a comparative study of the various switching strategies of 3L ANPC using the recently developed 10kV IGCTs which has the capability to raise the current and voltage rating of the wind turbines is carried out. The comparison is performed using ABB make 10kV IGCT 5SHY17L9000 and PLECs simulations.

• Journal of Power Electronics
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• v.19 no.1
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• pp.146-157
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• 2019

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

• Animal Bioscience
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• v.34 no.2
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• pp.306-311
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• 2021

Objective: The objectives were to develop prediction equations for digestible energy (DE) and metabolizable energy (ME) of feed ingredients and diets for pigs based on chemical composition and to evaluate the accuracy of the equations using in vivo data. Methods: A total of 734 data points from 81 experiments were employed to develop prediction equations for DE and ME in feed ingredients and diets. The CORR procedure of SAS was used to determine correlation coefficients between chemical components and energy concentrations and the REG procedure was used to generate prediction equations. Developed equations were tested for the accuracy according to the regression analysis using in vivo data. Results: The DE and ME in feed ingredients and diets were most negatively correlated with acid detergent fiber or neutral detergent fiber (NDF; r = -0.46 to r = -0.67; p<0.05). Three prediction equations for feed ingredients reflected in vivo data well as follows: DE = 728+0.76×gross energy (GE)-25.18×NDF (R2 = 0.64); ME = 965+0.66×GE-24.62×NDF (R2 = 0.60); ME = 1,133+0.65×GE-29.05×ash-23.17×NDF (R2 = 0.67). Conclusion: In conclusion, the equations suggested in the current study would predict energy concentration in feed ingredients and diets.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.459-468
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• 2020

The pole interaction of the line-commutated converter high-voltage direct current (HVDC) is analyzed, and a practical solution that uses a surge arrester is proposed. Jeju HVDC No. 2 is a double-monopole HVDC link that has a rated power capacity of 2 × 200 MW and was commissioned in 2012. During normal operation, Jeju HVDC No. 2 is operated in the bipolar mode to minimize the loss caused by the dedicated metallic return. However, when one pole of the inverter valve is bypassed, a commutation failure can occur in the other pole. This phenomenon is called pole interaction in this work. This pole interaction interrupts the HVDC power transfer for almost 2 s and may affect the stability of the power system. This research proposes the installation of a surge arrester at the inverter neutral, which can be an effective and practical solution for pole interaction. The HVDC system is analyzed, and the residual voltage of the surge arrester is determined. Detailed simulation using PSCAD/EMTDC demonstrates that the proposed method eliminates the pole interaction of the bipolar-operated HVDC.

• Corrosion Science and Technology
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• v.21 no.3
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• pp.221-229
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• 2022

To understand effects of cooling rates of coating layer on microstructures and corrosion behaviors of hot-dip alloy coated steel sheets (Zn-5%Al-2%Mg) in a neutral aqueous condition with chloride ion, a range of experimental and analytical methods were used in this study. Results showed that a faster cooling rate during solidification decreased the fraction of primary Zn, and increased the fraction of Zn-Al phase. In addition, interlamellar spacing became refined under a faster cooling rate. These modifications of the coating structure had higher open circuit potentials (OCP) with smaller anodic and cathodic current densities in the electrochemical potentiodynamic polarization. Surface analyses after a salt spray test showed that the increase in the Zn-Al phase in the coating formed under a faster cooling rate might have contributed to the formation of simonkolleite (Zn₅(OH)₈Cl₂·H₂O) and hydrotalcite (ZnAl₂(OH)₆Cl₂·H₂O) with a protective nature on the corroded outer surface, thus delaying the formation of red rust.

• Journal of the Korean institute of surface engineering
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• v.56 no.1
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• pp.12-39
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• 2023

Diseases caused by air pollution and abnormal climate are occurring worldwide due to global warming. Accordingly, the international community has established a strategy to respond to climate change, and major countries have shifted their economic policies to eco-friendly industries. In this study, we investigate the current status of the renewable energy industry and that of responses to carbon neutrality and PM2.5 (air pollution) in the three major Northeast Asian countries of Japan, Korea, and China, covering changes in the corporate perceptions of Environment, Social, Governance and RE100. In more detail, the three major Northeast Asian countries, referred to as the climate villains in the international community, explain the importance of successful entry into the electric vehicles (EV) industry for a rapid transition to an eco-friendly industry. Moreover, we study the application of lightweight materials for vehicles to improve mileage in the EV industry and technical problems to be solved in the future.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.23-26
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• 2006

For mechanical and electrical stability and environment protection. Cu and stainless steel stabilizers are laminated to a Ag layer to produce a composite neutral-axis(N-A) architecture in which the YBCO layer is centered between the oxide buffered metallic substrate and stabilizer strip lamination. This architecture allows the wire to meet operational requirements including stresses at cryogenic temperature. winding tensions as well as mechanical bending requirements including thermal and electrical stability under fault current conditions. We have experimentally studied mechanical properties of the laminated stainless steel and Cu stabilizers on YBCO coated conductors. We have laminated YBCO coated conductors by continuous dipping soldering process. We have investigated lamination interface between solder and stabilizer of the YBCO coated conductor. We evaluated bonding properties. tensile / shear bonding strength. and peeling strength laminated YBCO coated conductors.

• Asian Journal for Public Opinion Research
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• v.11 no.4
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• pp.304-326
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• 2023

News shows often deliver crosscutting information to their audiences by inviting commentators from rival political parties. If these news shows foster the formation of informed and balanced views of the audience, mass media could provide countermeasures against political polarization. To test the effect of such news shows, this study conducted an experiment with two variants of a simulated radio talk show. In the partisan scenario, the two guest commentators' affiliations suggested their ideological orientation. In the non-partisan scenario, the commentators had neutral affiliations. We divided participants into two ideology groups, liberals and conservative, and compared each group's evaluation of the commentators in the two scenarios. Two multivariate analysis of variance (MANOVA) tests were conducted to analyze the effect of the perceived ideology of the commentators on respondents' attitudes toward the commentators' arguments depending on their own ideological inclinations. The analyses results did not support the hypothesis that anticipated partisan attitudes towards the commentators' arguments. It was only the liberal respondents who showed statistically significant different attitudes toward commentators' arguments in each of the two scenarios. The findings suggest that such broadcast shows do not automatically trigger partisan message processing and may help the audience to develop informed and balanced opinions. While the current study failed to find conclusive evidence to support the hypotheses, it also found that the perceived ideology of the information source may trigger partisan attitudes for certain types of issues. Future studies with different experiment designs are needed to investigate the issue further.