• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.15-23
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• 2017

This paper reports a SOC(State-of-Charge) estimation method using the extended Kalman filter(EKF) algorithm, which can allow real-time implementation and reduce the error of the model and be robust against noise, to accurately estimate and evaluate the charging/discharging state of the EV(Electric Vehicle) battery. The battery was modeled as the first order Thevenin model for the EKF algorithm and the parameters were derived through experiments. This paper proposes the changed method, which can have the SOC to 0% ~ 100% regardless of the aging of the battery by replacing the rated capacity specified in the battery with the maximum chargeable capacity. In addition, This paper proposes the EKF algorithm to estimate the non-linearity interval of the battery and simulation result based on Ah-counting shows that the proposed algorithm reduces the estimation error to less than 5% in all intervals of the SOC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.142-149
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• 2011

This paper presents a new state of charge(SOC) estimation of large capacity of Li-ion battery (LIB) based on the multiple model adaptive estimation(MMAE) method. We first introduce an equivalent circuit model of LIB. The relationship between the terminal voltage and the open circuit voltage(OCV) is nonlinear and may vary depending on the changes of temperature and C-rate. In this paper, such behaviors are described as a set of multiple linear time invariant impedance models. Each model is identified at a temperature and a C-rate. These model set must be obtained a priori for a given LIB. It is shown that most of impedances can be modeled by first-order and second-order transfer functions. For the real time estimation, we transform the continuous time models into difference equations. Subsequently, we construct the model banks in the manner that each bank consists of four adjacent models. When an operating point of cell temperature and current is given, the corresponding model bank is directly determined so that it is included in the interval generated by four operating points of the model bank. The MMAE of SOC at an arbitrary operating point (T $^{\circ}C$, $I_{bat}$[A]) is performed by calculating a linear combination of voltage drops, which are obtained by four models of the selected model bank. The demonstration of the proposed method is shown through simulations using DUALFOIL.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1442-1445
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• 2007

Just noticeable differences (jnds) of autocorrelation function (ACF) parameters - Phi (0), Tau 1 and Phi 1 - of household refrigerator noise were investigated by psychoacoustical analyses. Phi (0) of five refrigerators' noise was changed with equal (${\pm}$) interval level of 0.5-1.0 dB up to five intervals by manipulating sound pressure level of the noise. Tau 1 and Phi 1 were varied with equal (${\pm}$) interval of around 0.10 ms and 0.02, respectively. Pitch shifting and strengthen methods were applied for the Tau 1 and Phi 1 variations. As results of subjective evaluations, about 2.0 dB was shown as jnd of Phi (0). The values of 0.30 ms and 0.06 were found as jnds of Tau 1 and Phi 1, respectively. The jnd results of each ACF parameter can be applied to explain substantial amount of sound quality (SQ) enhancement in the SQ prediction indices which were proposed in the authors' previous study [Sato et al. (2007) J. Acoust. Soc. Am.].

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.147-151
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• 2008

Purpose: The purposes of the authors' analysis were to assess the values that plastic surgery journals demonstrate in terms of the standardized measures created by the Korea Medical Citation Index, and to assess the relationship between these values and the turnaround time of these journals. Methods: The overall indexes of J Korean Soc Plast Reconstr Surg(JKSPRS), J Korean Soc Aesthetic Plast Surg(JKSAPS), J Korean Cleft Palate-Craniofac Assoc (JKCPRA) were compared with those of journals related with Korean plastic surgery using the following parameters: impact factor, cited half-life, total articles, and the number of journals. Korean plastic surgery journals were compared with journals from relative fields. In addition, an evaluation of all original articles published in 2007, assessing the time intervals from submission to publication was conducted for Korean plastic surgery journals and various journals which were related with plastic surgery. Results: The number of articles for Korean plastic surgery journals for 2006 ranged from 19 for JKCPRA to 149 for JKSPRS. The time interval from submission to publication of an article among Korean plastic surgery journals for 2007 ranged from 73.7 days for JKSAPS to 176.2 days for JKSPRS. The variation in impact factor of JKSPRS for the period from 2002 to 2005 increased from 0.084 in the year 2002 to 0.168 in 2005. But the impact factor in 2006 has fallen to 0.112. Conclusion: JKSPRS demonstrated comparatively high overall index values and a short turnaround time in comparison to relative journals. To improve the status of Korean plastic surgery journals, members of Korean plastic surgeons should quate Korean plastic surgery journals and adjust key word to MeSH. The title written down in Korean should use medical terminology published by Korean medical association.

• Journal of the Society of Disaster Information
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• v.8 no.3
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• pp.267-275
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• 2012

Long-term national railway building comprehensive review of the proposal had 100 in railway history, railway rail network plan. Planning routes for establishing a plan, but, considering the rail network, the plan was that could with the very important meaning in the What more economical route considering the costs and benefits of building a rail network under budget constraints, went through the process of background lines of business unit interval expenses to adopt a business unit interval. Especially in building the railway network, as well as the road plan was to reflect in order to build for the future railway facilities was secured examine the possibility of possible budget commitment. Budget of securing the transportation tax, gasoline tax, and other transportation facilities in order to secure and commit the current funding approach and Review Bodu possible budget scenarios based on it written. Was also enforce rail system built in reviewing the demand more than anything that can take advantage of the railway distance by railway and the merits of the competition means to compete in the form of the assumed situation. The rail network deployment plan, considering this was discussed, based on the results of the plan to establish the first annual or period of the plan change was based on the budget that was unknown.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.201-202
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• 2012

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charging mode, constant-current mode, and constant-voltage mode. Each mode is operated according to battery states: voltage, current and State of Charging (SOC). The proposed system is able to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 67A. The optimal discharging algorithm for Vehicle to the Grid (V2G) operation has been adopted to maintain the discharging current of 1C. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system. Experiment waveforms confirm the proposed functionality of the charging system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.679-686
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• 2006

Recently, the city railway in the Seoul Metropolitan Area (SMA) has offered a low quality of service as a passage time, because it was operated slowly. So, the people who live in modern society are not satisfied about passage time, therefore, this study tried to make that the subway in the SMA becomes a more functional and effective wide-area-transportation-network through an express train introduction's method which examined cases from abroad and current system. and then presented how express train could be applied to current system. In a case study, We used the An-San Line and Su-In Line as a examples and developed a schedule which can minimize the delaying time of subway by using Branch & Bound Algorithm. The train operational plan was loaded to consider a railroad siding, Obtained site, and the dispatch interval(three to ten minutes) for the express and local lines and finally, We presented an alternative operational plan which made by those factors.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.167-174
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• 2005

Purpose : Relapses are a major problem in children with steroid responsive nephrotic syndrome(SRNS). This study has been performed to determine the predictive factors for relapse in children with SRNS. Methods : The study group consisted of 7,3 children with SRNS who had been admitted to the Department of Pediatrics, Kyungpook National University Hospital, over 6 years from 1996 to 2001. The medical records were reviewed retrospectively and analyzed to determine significant relationships between selected variables[age at onset, sex, laboratory data, the rapidity of response(days to remission), interval to first relapse] and the frequency of relapse. Results : The age($mean{\pm}SD$) of patients was $4.53{\pm}2.53$ years old. The male to female ratio was 52:21. In 95$\%$, 39 out of the 41 children had a renal biopsy, and the final diagnosis was minimal change nephrotic syndrome. There was no significant correlation between the frequency of relapse and the following variables age at onset, sex, and presence of hematuria. However, the rapidity of response correlated well with the frequency of relapse, especially during the first year after the onset of the disease(P=0.005). Conclusion : The rapidity of response is expected to be one of the predictive (actors for relapse in children with SRNS. (J Korean Soc Pediatr Nephrol 2005;9:167-174)