• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.3
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• pp.139-146
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• 2019

As the number of electric vehicles (EVs) in Jejudo Island increases, the secondary use of EV batteries is becoming increasingly mandatory not only in reducing greenhouse gas emissions but also in promoting resource conservation. For the secondary use of EV batteries, their capacity and performance at the end of automotive service should be evaluated properly. In this study, the battery state information from the on-board diagnostics or OBD2 port was acquired in real time while driving three distinct routes in Jejudo Island, and then the battery operating characteristics were assessed with the driving routes. The route with higher altitude led to higher current output, i.e., higher C-rate, which would reportedly deteriorate state of health (SOH) faster. In addition, the SOH obtained from the battery management system (BMS) of a 2017 Kia Soul EV with a mileage of 55,000 km was 100.2%, which was unexpectedly high. This finding was confirmed by the SOH estimation based on the ratio of the current integral to the change in state of charge. The SOH larger than 100% can be attributed to the rated capacity that was lower than the nominal capacity in EV application. Therefore, considering the driving environment and understanding the SOH estimation process will be beneficial and necessary in evaluating the capacity and performance of retired batteries for post-vehicle applications.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.598-604
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• 2004

The mobile service was focused on voice and low rate data service. But recently high data rate service is getting more important, so mobile service operators are providing 1x EV-DO services for high data rate service. Many mobile repeaters were deployed for service coverage, but most of them were deployed when voice and low rate data service were main service. It is necessary to test whether these repeaters are suitable for 1x EV-DO networks for high rate data services. In field test, 1x EV-DO data rates were measured through various repeaters. Some repeaters showed data rates degradation compared with 1x EV-DO AN. The specifications of the repeaters were analyzed. And under the various radio environments such as fading and RSSI, data rates through repeater were tested. These test results will be useful for operation guide of repeaters in high data rate service networks.

• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.797-805
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• 2002

The EV ROM, a joint reservoir operation model for flood control that accounts for the downstream flow condition, has been introduced in the preceding article (Shin et al, 2000). A joint reservoir operation model computer program for the Geum river basin, developed by FORTRAN Power Station 4.0 using the EV ROM, is hereby presented. Three case studies of flood control by joint operation of the Yongdam and Daechung Multipurpose Dams in the Geum river basin revealed that the performance of the EV ROM was superior to the existing Rigid ROM and Technical ROM. This is because the EV ROM can account for the downstream flow condition as well as the upstream inflow and the reservoir water level. In order to apply for various floods events in the future, consistent improvement of the developed EV ROM and efforts for more accurate rainfall prediction are required.

• Information and Communications Magazine
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• v.21 no.7
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• pp.37-48
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• 2004

Both the 1xEV-DV and HSDPA are advanced standards which can make high speed packet data services come true in mobile communications environment. Both specifications look similar in a point of allocating their radio access resources based on the real-time variation of wireless channels. This paper introduces BTS modems and channel cards for 1xEV-DV and HSDPA developed by LG Electronics, Inc.

• Analytical Science and Technology
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• v.16 no.2
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• pp.159-165
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• 2003

To develop an ionic equilibria model applicable to the sulfuric acid leaching solutions of zinc oxide ore, the method of the Pitzer equation and that of the Vasil'ev equation were compared. As the ionic strength of the solution increased to 9 m, the results of ionic equilibria by the Pitzer equation were more accurate than those by Vasil'ev. To simulate the sulfuric acid leaching solutions of zinc oxide ore, the mixed solutions with the various composition of $ZnSO_4-Fe_2(SO_4)_3-Na_2SO_4-H_2SO_4-NaOH-H_2O$ were prepared. The pH values calculated in this study agreed well with those measured at $25^{\circ}C$.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.157-160
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• 2014

본 논문에서는 최근 주목받고 있는 임베디드 시스템 개발을 위한 소프트웨어 교육의 필요성을 살펴보고 이를 위해 레고 마인드스톰 EV3 교구를 활용한 학습프로그램을 개발하여 제안하고자 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.65-73
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• 2008

Security layer of the Cdma2000 1x EV-DO is currently completing standard (C.S0024-A v2.0). Accordingly, a hardware security devices, that allows to implementation requirement of the security layer described in standard document, is required to apply security function about data transferred between AT and AN of then Cdma2000 1x EV-DO environment. This paper represents design of hardware device providing EV-DO security with simulation of the security layer protocol via the FPGA platform. The SHA-1 hash algorithm for certification and service of packet data, and the AES, SEED, ARIA algorithms for data encryption are equip in this device. And paper represents implementation of hardware that applies optionally certification and encryption function after executing key-switch using key-switching algorithm.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.265-266
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• 2016

본 논문에서는 EV와 NEV 겸용 모듈형 급속충전기를 위한 10kW급 3레벨 DC-DC 컨버터를 제안한다. 제안한 컨버터는 600V 정격의 MosFET로 고속스위칭을 위하여 3레벨 컨버터를 채용하였고 순환전류를 최소화하기 위하여 커플인덕터를 적용한 듀티제어방식의 풀브릿지 컨버터로서 스위치의 ZVS 턴 온과 다이오드의 ZCS 턴 오프를 성취하였다. 또한 EV(200~500V)와 NEV(50~100V)의 넓은 충전전압 범위에서 고효율을 달성하기 위해 하이브리드 스위칭기법을 적용하였다. 10kW 시작품 개발을 통해 정격부하 효율 97.32%, 최고효율 97.43%를 달성하였다.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.137-167
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• 2015

Based on the stakeholder theory, this paper analyzes a clash of standards in Korea's Electric Vehicle(EV) market, particularly between an EV charging standard and a smart grid communication standard in 2012~2013. For charging, EV is connected with the electric power grid and simultaneously exchanges data regarding the charging status. When EV is connected with the power grid, a clash between two standards may arise. It actually happened when BMW entered into the Korean EV market with the DC Combo charging system. In that course, the frequency interference occurred between the EV data communication technology adopted by BMW and the AMI(Advanced Metering Infrastructure) for the smart grid system in Korea. Standardization of Korea's EV charging systems was required to solve this problem. However, it had been delayed due to the confrontation between various stakeholders involved in the process of standardization. It lasted until the DC combo was accepted as one of the Korea EV charging standards(KSAE SAE 1772-2040, 2014.1) by KSAE(The Korea Society of Automotive Engineers) in January 2014. This is an interesting case in the age of convergence. As it deals with the standard competition not among EV standards, but a clash between the EV industry and the smart grid, i.e. electric power industry, it addresses the necessity to consider standardization processes between different industries. This study draws on the stakeholder theory to analyse the dynamics of the standard clash between EV charging systems and the smart grid system, which is a unique example of standard clash between different industries. We expect such clashes to increase in the age of convergence.