• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.834-844
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• 2012

Nonlinear electronic loads draw harmonic currents from the power grids that can cause energy loss, miss-operation of power equipment, and other serious problems in the power grids. This paper proposes a harmonic compensation method using multiple distributed resources (DRs) such as small distributed generators (DGs) and battery energy storage systems (BESSs) that are integrated to the power grids through power inverters. For harmonic compensation, DRs should inject additional apparent power to the grids so that certain DRs, especially operated in proximity to their rated power, may possibly reach their maximum current limits. Therefore, intelligent coordination methods of multiple DRs are required for efficient harmonic current compensation considering the power margins of DRs, energy cost, and the battery state-of-charge. The proposed method is based on fuzzy multi-objective optimization so that DRs can cooperate with other DRs to eliminate harmonic currents with optimizing mutually conflicting multi-objectives.

• Environmental and Resource Economics Review
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• v.10 no.3
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• pp.413-431
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• 2001

Previous analyses of deposit-refund systems (hereafter DRS) mosty concerned consumer-paid DRS. While there has been a trend to put more emphasis on the producers' responsibility in recycling, especilly in Europe, and the supplier-paid DRS has been enforced in Korea during the past decade, little attempt has been made to analyse rigorously the nature of the supplier-paid DRS. This paper looks into the effects of the supplier-paid DRS on firm behaviors and profits under the oligopolistic market structure. It is shown that, in the cournot model where firms strategically interact each other, when the deposit rate is high enough, firms' profit increase as the deposit rate rises. Furthermore, where the number of firms are sufficiently large, it can happen that, as the deposit rate increases, both social welfare and firms' profit improve.

• Journal of Oriental Neuropsychiatry
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• v.12 no.2
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• pp.185-191
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• 2001

Objectives: This study aimed to evaluate the usefulness as a screening test of Clock Drawing Test(CDT) compared with the standard K-DRS in probably dementia. Methods: The subjects for this study consisted of 19 elderly persons who visited to the outpatient department of Oriental Neuropsychiatry of the Kyunghee Oriental hospital. They received the K-DRS and the Clock Drawing Test. Three observers evaluated them with circle, numbers, hands. Inter-rater reliability of scores from Clock Drawing Test was assessed and Pearson correlation coefficients were used to examined the relationships between scores from Clock Drawing Test and K-DRS. Results: Correlations between individual raters was highly significant (r= .957, .974, and .970, respectively: p<.001). There was stastically significant correlations between K-DRS and CDT scores (r= 0.849, p<.001). Conclusions: The CDT can be rated reliably by observers and correlations between CDT and K-DRS is significantly high. We confirmed the usefulness of CDT as simple, easily administered, low cost, and reliable general screening test for dementia.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.223-229
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• 2005

DRS (Disaster Recovery System) that was invested on a large-scale becomes obsolete when it is neglected for a certain Period of time. Also the DRS can not be accomplished through the duplicated computer systems. When a disaster happens, the normal operation is possible only if the processes that had been being done before the disaster recover without any loss. Therefore the DRS is not a IT project but needs an analysis of whole business Processes and business continuity plans. This paper analyze the present state of DRS of the domestic bank industry and suggests a remedy.

• The Journal of Korean Association of Computer Education
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• v.12 no.2
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• pp.77-86
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• 2009

Large-scale applications, that needs large-capacity R&D resources and realtime data transmission, have demanded more stable and high-performance network environment than current Internet environments. Recently, global R&D networks have focuses on utilizing Lambda networking technologies and resource reservation systems to be satisfied with various applications' requirements. In this paper, we modify the existing DRS (Dynamic Right-Sizing) model to reflect various advantages in terms of the stability and high-capacity of Lambda network. In addition, we suggest the design methodology of high-performance Lambda network, which can integrate NRPS (Network Resource Provisioning System) into our modified DRS model.

• Journal of Oriental Neuropsychiatry
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• v.14 no.1
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• pp.17-26
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• 2003

Objective : The clinical efficacy of Jowiseungchungtang(oriental herbal medication) over 6-month on the cognitive function in patients with mild Dementia of Alzheimer type(DAT) was investigated in this study. Method : The subjects for this study consisted of dementia patients who visited to the outpatient dementia department of Oriental Neuropsychiatry of the Kyunghee Oriental hospital. Patients were required to have at entry: a dignosis of mild DAT; Biochemical test, CBC, Urine analysis, Chest X -ray, EKG, Brain- MRI, Mini-Mental States-Korea(MMSE-K), Korean-Dementia Rating Scale(K-DRS), Samsung Dementia Questionaire(SDQ;to their caregiver). Patients(n=31) were assigned to treatment with Jowiseungchungtang (fourth/day for 6-month). The primary outcome measure was K-DRS. Result : 1. Patients' mean age was $71.4{\pm}6.6$ years(range 59 to 86 years). 2. Patients' mean education was $6.1{\pm}4.9$ years. K-DRS scores at baseline was $110.5{\pm}12.2$. K-DRS scores at 6-month was $109.0{\pm}17.0$. K-DRS scores at 6-month was not significantly different with K-DRS scores at baseline(t=.791 r=.435 p<.05). Conclusion : Treatment with Jowiseungchungtang for 6-month protected the cognitive function decline in patients with mild DAT.

• Advances in Energy Research
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• v.3 no.2
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• pp.81-95
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• 2015

Microgrid, which can be considered as an integration of various dispersed resources (DRs), is characterized by number of DRs interfaced through the power electronics converters. The microgrid comprising these DRs is often operated in an islanded mode. To minimize the cost, reduce complexity and increase reliability, it is preferred to avoid any communication channel between them. Consequently, the droop control method is traditionally adopted to distribute active and reactive power among the DRs operating in parallel. However, the accuracy of distribution of active and reactive power among the DRs controlled by the conventional droop control approach is highly dependent on the value of line impedance, R/X i.e., resistance to reactance ratio of the line, voltage setting of inverters etc. The limitations of the conventional droop control approach are demonstrated and a modified droop control approach to reduce the effect of impedance mis-match and improve the time response is proposed. The error in reactive power sharing is minimized by inserting virtual impedance in line with the inverters to remove the mis-match in impedance. The improved time response is achieved by modifying the real-power frequency droop using arctan function. Simulations results are presented to validate the effectiveness of the control approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.451-454
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• 2008

2001년 세계무역센터의 테러사건을 계기로 구축되기 시작한 국내 재해복구시스템(DRS)은 재해가 발생할 상황에서만 활용되고, 그 이외의 용도로는 사용되지 못하고 있기 때문에 시스템 활용률이 낮다. 이러한 점에 착안하여 본 연구에서는 재해복구시스템의 가용성 및 활용성을 높일 수 있는 방안을 제시하고자 한다. 재해복구시스템은 재해가 발생했을 때뿐만 아니라 시스템 장애나 테스트시스템, 웹 서버 및 재해복구 네트워크의 활용 용도로 확대 운영할 수 있음을 본 연구에서 보여준다. 또한 이미 구축된 재해복구시스템의 사용 현황을 분석하고, 재해복구시스템의 용도 개선 방안을 제시함으로써 향후 재해복구시스템의 가용성 및 활용도를 높이고자 한다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.313-317
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• 2006

To prepare oligouronic acids from high-molecular-weight alginates, sea tangle (Laminaria japonica) alginates were hydrolyzed at various pHs for 1 hr at 80$^{\circ}C$. The effects of hydrolysis pH (HpH) on the average molecular weight (AMW) and MW distribution ratios (DRs) in the hydrolyzed alginates were investigated. As HpH decreased, the DRs of the alginates with MW>500 kDa and MW=300-500 kDa decreased exponentially, while it increased exponentially for MW<50 kDa. For MW=100-300 kDa, DR increased exponentially as HpH fell from 5.0 to 3.5, and then decreased exponentially. Similarly, for MW=50-100 kDa, DR increased exponentially as HpH increased to 1.0 from 5.0, and then decreased exponentially. As HpH decreased, the MW cutoff size and AMW of alginates fraction with the highest DR were decreased. For HpH 4.5 and 5.0, the MW cutoff size with the highest DRs was MW=300-500 kDa; the DRs were 28.9 and 32.6%, respectively; and the AMW of both was about 400 kDa, for HpH 3.5 and 4.0, the cutoff size was MW=100-300 kDa; the DRs were about 28%: and the AMWs were both about 200 kDa. For HpH 3.0, the cutoff size was MW=50-100; the DR was 29.0%; and the AMW was 73 kDa. For HpH values below 2.0, the MW cutoff size with the highest DRs was MW<50 kDa, and all of the AMWs were below 28 kDa.

• Journal of Oriental Neuropsychiatry
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• v.15 no.2
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• pp.141-148
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• 2004

Objective : This study is designed to assess the effects of Gongjin-dan on cognitive decline of the patients with mild Dementia of Alzheimer Type(DAT). Method : 33 patients with mild DAT were measured by using K-DRS, and after 100 days again. During 100 days the patients with mild DAT were treated with Gongjin-dan. The scores of K-DRS between before and after treatment were analyzed by paired t-Test. Result : 1. the mean age of patients was $70.3{\pm}4.1$ years (range 65 to 84 years) 2. the mean education of patients was $5.5{\pm}5.3$ years 3. the mean K-DRS score of the patients before treatment was $93.2{\pm}12.1$, and the mean K-DRS score of the patients after treatment was $114.7{\pm}14.5$. K-DRS scores after treatment was significantly different with the K-DRS scores before treatment.(t=9.907, r=.573, p<.00l) Conclusion : Treatment with Gongjin-dan for 100 days increased the cognitive ability in patients with mild DAT