• Resources Recycling
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• v.31 no.4
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• pp.3-11
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• 2022

Owing to the increasing demand for electric vehicles (EVs), appropriate management of their waste batteries is required urgently for scrapped vehicles or for addressing battery aging. With respect to technological developments, data-driven diagnosis of waste EV batteries and management technologies have drawn increasing attention. Moreover, robot-based automatic dismantling technologies, which are seemingly interesting, require industrial verifications and linkages with future battery-related database systems. Among these, it is critical to develop and disseminate various advanced battery diagnosis and assessment techniques to improve the efficiency and safety/environment of the recirculation of waste batteries. Incorporation of lithium-related chemical substances in the public pollutant release and transfer register (PRTR) database as well as in-depth risk assessment of gas emissions in waste EV battery combustion and their relevant fire safety are some of the necessary steps. Further research and development thus are needed for optimizing the lifecycle management of waste batteries from various aspects related to data-based diagnosis/classification/disassembly processes as well as reuse/recycling and final disposal. The idea here is that the data should contribute to clean design and manufacturing to reduce the environmental burden and facilitate reuse/recycling in future production of EV batteries. Such optimization should also consider the future technological and market trends.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.122-129
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• 2010

Purpose : Enteroviral infection is a common viral illness in children. We undertook this study in attempt to comprehend the epidemiologic and clinical features of enteroviral infections, particularly EV71 in children. Methods : We enrolled 63 children with enteroviral infection at Severance Children's Hospital in Seoul between May and August 2009. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed from stool or cerebrospinal fluid samples, which were then tested for enteroviral infection. Viral isolation and serotype identification also were performed by RT-PCR. Results : A total of 63 patients with clinical diagnosis of enteroviral infections were enrolled; of those, 38 (60%) were positive for enterovirus. The mean age of the patients was 2 years and 7 months and the sex ratio of male to female was 0.9 :1. Their clincal manifestations included aseptic meningitis (21 cases, 55%), HFMD (16 cases, 42%), herpangina (5 cases, 13%), neonatal fever (2 cases, 5%), encephalitis (1 case, 3%), and myocarditis (1 case, 3%). Serotypes of isolated enteroviruses were EV71 (8 cases, 21%), coxsackievirus B1 (8 cases, 21%), coxsackievirus A16 (2 cases, 6%), coxsakievirus A2 (1 case, 3%), coxsakievirus A5 (1 case, 3%), and echovirus 9 (1 case, 3%). Clinical symptoms of EV71 infection included HFMD (5 cases, 63%), aseptic meningitis (3 cases, 38%), encephalitis (1 case, 13%), and myocarditis (1 case, 13%). A positive rate of C-reactive protein in EV71 was higher than those in other enterviral infections. However, there was no statistically significant difference in other laboratory findings. Conclusion : We reported on identified enteroviruses, including EV71, during a period of 3 months in the summer of 2009. In this study, EV71 infection frequently occurred in male and clinical manifestation caused by EV71 was a more severe disease than that due to other enterviral infections. There is a need for continuous surveillance of enteroviral infection and its clinical manifestations for diagnosis and treatment of enteroviral infection.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.3
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• pp.182-189
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• 2018

LLC resonant converters or phase-shift full-bridge converters have been widely used as DC - DC converters for rapid charging of electric vehicles (EVs). However, these converters present critical disadvantages, including a large circulating current, which can hinder efficiency and miniaturization in EV battery charger applications. In this paper, a new DC - DC converter topology is proposed for EV rapid chargers. The proposed converter can operate at high frequency despite a high rated power capacity of over 20kW, and the problem of circulating current can be minimized during the entire battery charging time. Owing to these advantages, the proposed converter can achieve a high conversion efficiency of over 97% for EV rapid charger applications. The performance of the proposed converter is verified with 20kW prototypes in this study.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.60-64
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• 2001

This study was carried out to investigate effects of sowing dates and method on major agronomic characteristics of Dendropanax morbifera $L_{EV}$. in southern area of Korea. The number of days from sowing to emergence was recognized liner negative correlation between sowing days. Dendropanax morbifera was sowed at seven different dates(from Dec.20 to Feb.20 at 30 days interval, from Mar, 1 to Apr. 15 at 15 days interval) in pot culture. In sowing date at Mar. 15, germination rate and early growth were good in pot. Dendropanax morbifera was sowed at five different dates(from Dec.20 to Apr.15 at 15 days interval) in field culture. In sowing date at Apr.15, germination rate and early growth were good in field culture.

• Elastomers and Composites
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• v.53 no.3
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• pp.150-157
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• 2018

Fatigue properties of rubber are one of the most important characteristics in the rubber industry. In this study, the fatigue properties of MREs (magneto-rheological elastomers) based on NR (natural rubber), EPDM (ethylene-propylene diene monomer), and AEM (ethylene/acrylic elastomer) were investigated. For comparison, MREs with a Shore hardness of 60A were prepared. According to the relative results, the fatigue properties of EPDM MRE were the worst. Thus, we investigated methods to improve the fatigue properties of EPDM MRE by varying the carbon black content and curing systems of EPDM as the matrix of the MRE. Dynamic properties were measured using a fatigue tester and an RPA (rubber process analyzer), and the XPS (X-ray photoelectron spectroscopy) was used to analyze the curing system of the EPDM matrix. According to the results, the Payne effect increased and the fatigue resistance decreased as the carbon black content increased. In case of the curing system, the CV (conventional vulcanization) system was superior to the EV (efficient vulcanization) system in terms of the fatigue resistance. This was because the number of flexible bonds in the case of the CV system was higher than that in the case of the EV system. However, the EV system showed excellent mechanical properties because it had many monosulfidic bonds with strong binding energy.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.185-192
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• 2017

This paper proposes a single-stage interleaved soft-switching electrolytic capacitor-less EV charger with reduced component count and simple circuit structure. The proposed charger achieves ZVS turn-on of all switches and ZCS turn-off of all diodes without regard to voltage and load variation. It achieves high power density even without an input filter due to CCM operation and bulky electrolytic capacitors and without a low-frequency component in the transformer. A 2 kW prototype of the proposed charger with sinusoidal charging is built and tested to verify the validity of the proposed operation.

• Asia Marketing Journal
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• v.18 no.3
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• pp.47-63
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• 2016

Rational choice theory holds that the alternative with largest expected utility in the choice set should always be chosen. However, it is often observed that an alternative with the largest expected utility is not always chosen while the choice task itself being avoided. Such a choice phenomenon cannot be explained by the traditional expected utility maximization principle. The current study posits shows that such a phenomenon can be attributed to the gap between the expected perceived gain (or loss) and the expected perceived value. This study mathematically analyses the relationship between the expectation of an alternative's gains or losses over the reference point and its expected value, when the perceived gains or losses follow continuous probability distributions. The proposed expected value (EV) function can explain the effects of loss aversion and uncertainty on the evaluation of an alternative based on the prospect theory value function. The proposed function reveals why the expected gain of an alternative should exceed some positive threshold in order for the alternative to be chosen. The model also explains why none of the two equally or similarly attractive options is chosen when they are presented together, but either of them is chosen when presented alone. The EV function and EG-EV curve can extract and visualize the core tenets of the prospect theory more clearly than the value function itself.

• The Korean Journal of Applied Statistics
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• v.23 no.3
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• pp.471-485
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• 2010

VaR is used extensively as a tool for risk management by financial institutions. For convenience, the normal distribution is usually assumed for the measurement of VaR, but recently the method using extreme value theory is attracted for more accurate VaR estimation. So far, GEV and GPD models are used for probability models of EVT for the VaR estimation. In this paper, the PP model is suggested for improved VaR estimation as compared to the traditonal EV models such as GEV and GPD models. In view of the stochastic process, the PP model is regarded as a generalized model which include GEV and GPD models. In the empirical analysis, the PP model is shown to be superior to GEV and GPD models for the performance of VaR estimation.

• Progress in Superconductivity and Cryogenics
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• v.16 no.3
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• pp.21-25
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• 2014

As wireless power transfer (WPT) technology using strongly coupled electromagnetic resonators is a recently explored technique to realize the large power delivery and storage without any cable or wire, this technique is required for diffusion of electric vehicles (EVs) since it makes possible a convenient charging system. Typically, since the normal conducting coils are used as a transmitting coil in the CPT system, there is limited to deliver the large power promptly in the contactless EV charging system. From this reason, we proposed the combination CPT technology with HTS transmitting antenna, it is called as, superconducting contactless power transfer for EV (SUWPT4EV) system. As the HTS coil has an enough current density, it can deliver a mass amount of electric energy in spite of a small scale antenna. The SUCPT4EV system has been expected as a noble option to improve the transfer efficiency of large electric power. Such a system consists of two resonator coils; HTS transmitting antenna (Tx) coil and normal conducting receiver (Rx) coil. Especially, the impedance matching for each resonator is a sensitive and plays an important role to improve transfer efficiency as well as delivery distance. In this study, we examined the improvement of transmission efficiency and properties for HTS and copper antennas, respectively, within 45 cm distance. Thus, we obtained improved transfer efficiency with HTS antenna over 15% compared with copper antenna. In addition, we achieved effective impedance matching conditions between HTS antenna and copper receiver at radio frequency (RF) power of 370 kHz.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.3
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• pp.67-77
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• 2024

Increasing energy efficiency in factories is an activity aimed at optimizing resource allocation in manufacturing processes to establish production plans. However, this strategy may not apply effectively when night shifts are unavoidable. Additionally, continuous fluctuations in production requirements pose challenges for its implementation in the factory. Recently, with the rapid proliferation of electric vehicles (EVs), technology utilizing electric vehicle batteries as energy storage systems has gained attention. Technology using these batteries can be an alternative for factory energy management. In this paper, a factory energy management method using EV batteries is proposed. The proposed method is analyzed using PSCAD/EMTDC software, considering the state of charge of EV batteries and Time-of-Use (TOU) rates. The proposed method was compared with production scheduling established considering predicted power usage and TOU rates. As a result, production scheduling saved 4,152 KRW per day, while the proposed method saved 7,286 KRW in electricity costs. Through this paper, the possibility of utilizing EV batteries for factory energy management has been demonstrated.