• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.381-387
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• 1994

In this paper, we found the improved SPICE heat transfer modeling of impulsed magnetizing fixture system and investigated temperature characteristics using the proposed model. As the detailed thermal characteristics of magnetizing fixture can be obtained, the efficient design of the impulsed magnetizing fixture which produce desired magnet will be possible using our heat transfer modeling. The knowledge of the temperature of the magnetizing fixture is very important of forecast the characteristics of the magnetizing fixture which produce desired magnet will be possible using our heat transfer modeling. The knowledge of the temperature of the magnetizing fixture is very important to forecast the characteristics of the magnetizing circuits under different conditions. The capacitor voltage was not raised above 810[V] to protect the magnetizing fixture from excessive heating. The purpose of this work is to compute the temperature increasing for different magnetizing conditions. The method uses multi-lumped model with equivalent thermal resistance and thermal capacitance. The reliable results are obtained by using iron core fixture (stator magnet of air cleaner DC motor) coupled to a low-voltage magnetizer(charging voltage : 1000[V], capacitor : 3825[$\mu$F]. The modeling and experimental results are in close aggrement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.351-352
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• 2007

Polymers submitted to thermo/electrical stress suffer from ageing that can drastically affect their functional behaviour. Understanding the physico/chemical processes at play during ageing and defining transport regimes in which these mechanisms start to be critical is therefore a prime goal to prevent degradation and to develop new formulation or new materials with improved properties. It is thought that a way to define these critical regimes is to investigate under which conditions (in terms of stress parameters) light is generated in the material by electroluminescence (EL). This can happen through impact excitation/ionization involving hot carriers or upon bi-polar charge recombination (a definition that excludes light from partial discharges, which would sign an advanced stage in the degradation process). After a brief review of the EL phenomenology under DC, we introduce a numerical model of charge transport postulating a recombination controlled electroluminescence. The model output is critically evaluated with special emphasize on the comparison between simulated and experimental light emission. Finally, we comment some open questions and perspectives.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.54-63
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• 2007

This paper is proposed a novel method that computed approximately maximum power of photovoltaic system and solar tracking method. Proposed novel is linear reoriented coordinates method(LRCM), this paper is proposed new mathematical dynamic model using LRMC and DC dynamic equation. LRCM has the advantage that is decreased calculating time, decides optimal voltage and maximum power that generates continually. Furthermore solar tracking method is improved over 50[%] photovoltaic efficiency than fixed method. This paper is proposed MPPT using LRCM and solar tracking method using program method that is adequate domestic conditions, prove verify of proposed method through experiment.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.528-537
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• 2008

Primary frequency control(PFC) has the ability to regulate short period random variations of frequency during normal operation conditions and also to respond rapidly to emergencies. However, during the past decade, numerous significant sized blackouts occurred worldwide that resulted in serious economic losses. Therefore, the conclusion has been reached that the ability of the current PFC to meet an emergency is poor, and security of power systems should be improved. An alternative to enhance the PFC and thus security is to store excessive amounts of energy during off-peak load periods in efficient energy storage systems for substituting the primary control reserve. In this sense, superconducting magnetic energy storage(SMES) in combination with a static synchronous compensator(STATCOM) is capable of supplying power systems with both active and reactive powers simultaneously and very rapidly, and thus is able to enhance the security dramatically. In this paper, a new concept of PFC based on incorporating a STATCOM-SMES is presented. A complete detailed model is proposed and a new control scheme is designed, comprising an enhanced frequency control scheme, and a fully decoupled current control strategy in d-q coordinates with a novel controller to prevent dc bus capacitors voltage drift/imbalance. The performance of the proposed control schemes is validated through digital simulation carried out using MATLAB/Simulink.

• Journal of Power Electronics
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• v.16 no.3
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• pp.823-831
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• 2016

A high-efficiency method is proposed to suppress magnetic core imbalance in phase-shifted full-bridge (PSFB) converters. Compared with conventional solutions, such as controlling peak current mode (PCM) or adding DC blocking capacitance, the proposed method has several advantages, such as lower power loss and smaller size, because the additional current sensor or blocking capacitor is removed. A time domain model of the secondary side is built to analyze the relationship between transformer core imbalance and cathode voltage of secondary side rectifiers. An approximate control algorithm is designed to achieve asymmetric phase control, which reduces the effects of imbalance. A 60 V/15 A prototype is built to verify the proposed method. Experimental results show that the numerical difference of primary side peak currents between two adjacent cycles is suppressed from 2 A to approximately 0 A. Meanwhile, compared with the PCM solution, the efficiency of the PSFB converter is slightly improved from 93% to 93.2%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.452-458
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• 2008

The effect of fermented soybean culture of Bacillus subtilis MORI mixed with mulberry leaves on the lowering the levels of blood glucose and cholesterol was examined using neonatal streptozotocin-induced diabetic (n-STZ) rats. B. subtilis MORI produces 1-deoxynojirimycin (DNJ), an $\alpha$-glucosidase inhibitor. The content of DNJ of soybean fermented culture mixed with mulberry was higher (4.1$\pm$0.0 mg/g dry base) than that (1.5$\pm$0.0 mg/g) of mulberry. The concentration of 50% inhibition (IC50) against rat intestinal $\alpha$-glucosidase of soybean fermented culture mixed with mulberry was $5.6{\pm}0.1{\mu}g$/mL and that of mulberry was $17.0{\pm}0.5{\mu}g$/mL. Experimental groups of diabetic rats were randomly assigned to normal control group (NC group), diabetic control group (DC group) and three diabetic groups fed with DNJ food product. One of the three diabetic groups was M group (60 mg DNJ food product/kg) (DNJ food product containing 30% mulberry) and the other two were MM-60 group (60 mg/kg) and MM-120 group (120 mg/kg) (DNJ-fortified food product containing 30% fermented soybean culture mixed with mulberry leaves). The glucose in serum was significantly decreased in the MM-60 and MM-120 groups fed with DNJ-fortified food product for 4 weeks, compared with DC group. Total cholesterol and triglyceride in serum were also lower in MM-60 and MM-120 groups than the DC group. These results support that the fermented soybean culture of B. subtilis MORI mixed with mulberry leaves improved the metabolism of blood glucose and lipid in the n-STZ rat model.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.304-308
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• 2014

Accurate prediction of peak bloom dates (PBD) of flowering cherry trees is critical for organizing local cherry festivals and other associated cultural and economic activities. A two-step phenology model is commonly used for predicting flowering time depending on local temperatures as a result of two consecutive steps followed by chill and heat accumulations. However, an extensive computation requirement for parameter estimation has been a limitation for its practical use. We propose a sequential parameterization method by exploiting previously unused records of development stages. With an extra constraint formed by heat accumulation between two intervening stages, each parameter can then be solved sequentially in much shorter time than the brute-force method. The result was found to be almost identical to the previous solution known for cherry trees (Prunus ${\times}$ yedoensis) in the Tidal Basin, Washington D.C.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.273-282
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• 2011

This study was to investigate the effect of improve forelimb sensorimotor function and neurotrophic factor(GAP-43) expression when differing an application time of tDCS in ischemic brain injury rat model(pre, $1^{st}$, $7^{th}$, $14^{th}$). Focal ischemic brain injury was induced in 80 Sprague-Dawley rats through middle cerebral artery occlusion(MCAO) by 'Longa' method. And then experimental groups were randomly divided into four groups; GroupI: MCAO induction, GroupII: application of tDCS(10 min) after MCAO induction, GroupIII: application of tDCS(20 min) after MCAO induction, GroupIV: application of tDCS(30 min) after MCAO induction. Modified limb placing test and single pellet reaching test were performed to test forelimb sensorimotor function. And the histological examination was also observed through the immunohistochemistric response of GAP-43(growth-associated protein-43) in the cerebral cortex. In modified limb placing test, groupIII(p<0.05) showed significantly improve than the other groups on $14^{th}$). day. In single pellet reaching test, groupIII(p<0.01) and groupIV(p<0.05) significantly improved on $14^{th}$) day. And in immunohistochemistric response of GAP-43, group III showed significantly positive response than the other groups on $14^{th}$ day. These results suggest that the intensity(0.1 mA)/time(20 min) condition of tDCS application has a significant impact on the sensorimotor functional recovery in focal ischemic brain injury rat models.

• International Commerce and Information Review
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• v.18 no.4
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• pp.55-78
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• 2016

In this study, service quality attributes of uTradeHub were classified based on the Kano model, and quality attributes that should be managed in priority to improve the service quality of uTradeHub were investigated using Timko's customer satisfaction coefficient(CSC) and average satisfaction coefficient(ASC). The results of the study are summarized as follows. First, as a result of classifying service quality attributes based on Kano model, 12 one dimensional qualities, 5 must-be qualities, 2 indifferent qualities were deducted, and many quality attributes of uTradeHub service were confirmed to be one dimensional quality to which is needed to be paid attention and paid more detailed attention to enhance service quality. Second, in the analysis result using Timko's customer satisfaction coefficient, "post processing for problems and complaints", "cost reduction", "efficiency of business processing" were ranked in the top of satisfaction coefficient, and they found to be quality attributes that customer satisfaction increases when service quality was satisfied. While, "post processing for problems and complaints", "interaction", "ability to respond promptly when problems occur" were ranked in the top of unsatisfaction coefficient, and they were analysed to be quality attributes that customer complaints increase when service quality was unsatisfied. Third, in the result of analyzing the quality attributes that should be managed in priority to improve the service quality of uTradeHub based on the average satisfaction coefficient(ASC), "post processing for problems and complaints", "cost reduction", "useful information" were ranked in the top 3, and they were classified as quality attributes that the satisfaction level increases more when they are improved than now, but the satisfaction level decreases when they are worsen.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2419-2423
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• 2015

Background: There are few choices for treatment of advanced cancer patients who do not respond to or tolerate conventional anti-cancer treatments. Therefore this study aimed to deploy the benefits and clinical efficacy of continuous dendritic cell-cytokine induced killer cell infusions in such patients. Materials and Methods: A total of 381 infusions (from 67 advanced cases recruited) were included in this study. All patients underwent peripheral blood mononuclear cell apheresis for the following cellular therapy and dendritic cells-cytokine induced killer cells were expanded in vitro. Peripheral blood T lymphocyte subsets were quantified through flow cytometry to address the cellular immunity status. Clinical efficacy and physical activities were evaluated by RECIST criteria and Eastern Cooperative Oncology Group scores respectively. Logistic regression model was used to estimate the association between cellular infusions and clinical benefits. Results: An average of $5.7{\pm}2.94{\times}10^9$ induced cells were infused each time and patients were exposed to 6 infusions. Cellular immunity was improved in that cytotoxic $CD8^+CD28^+$ T lymphocytes were increased by 74% and suppressive $CD8^+CD28^-$ T lymphocytes were elevated by 16% (p<0.05). Continuous infusion of dendritic cells-cytokine induced killer cells was associated with improvement of both patient status and cellular immunity. A median of six infusions were capable of reducing risk of progression by 70% (95%CI 0.10-0.91). Every elevation of one ECOG score corresponded to a 3.90-fold higher progression risk (p<0.05) and 1% increase of $CD8^+CD28^-$ T cell proportion reflecting a 5% higher risk of progression (p<0.05). Conclusions: In advanced cancer patients, continuous dendritic cell-cytokine induced killer cell infusions are capable of recovering cellular immunity, improving patient status and quality of life in those who are unresponsive to conventional cancer treatment.