• Transactions on Electrical and Electronic Materials
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• 제18권6호
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• pp.350-358
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• 2017

Recently, owing to increased interest in low-carbon energy supplies, renewable energy sources such as photovoltaics and wind turbines in distribution networks have received considerable attention for generating clean and unlimited energy. The presence of energy storage systems (ESSs) in the promising field of active distribution networks (ADNs) would have direct impact on power system problems such as encountered in probabilistic distributed generation (DG) model studies. Hence, the optimal procedure is offered herein, in which the simultaneous placement of an ESS, photovoltaic-based DG, and wind turbine-based DG in an ADN is taken into account. The main goal of this paper is to maximize the net present value of the loss reduction benefit by considering the price of electricity for each load state. The proposed framework consists of a scenario tree method for covering the existing uncertainties in the distribution network's load demand as well as DG. The collected results verify the considerable effect of concurrent installation of probabilistic DG models and an ESS in defining the optimum site of DG and the ESS and they demonstrate that the optimum operation of an ESS in the ADN is consequently related to the highest value of the loss reduction benefit in long-term planning as well. The results obtained are encouraging.

• Journal of Power Electronics
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• 제18권6호
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• pp.1855-1865
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• 2018

This paper presents a control strategy for voltage-controlled multi-function distributed generation (DG) combined with an active power filter (APF) and a reactive power compensator. The control strategy is based on droop control. As a result of local nonlinear loads, the voltages of the point of common coupling (PCC) and the currents injecting into the grid by the DG are distorted. The power quality of the PCC voltage can be enhanced by using PCC harmonic compensation. In addition, with the PCC harmonic compensation, the DG offers a low-impedance path for harmonic currents. Therefore, the DG absorbs most of the harmonic currents generated by local loads, and the total harmonic distortion (THD) of the grid connected current is dramatically reduced. Furthermore, by regulating the reactive power of the DG, the magnitude of the PCC voltage can be maintained at its nominal value. The performance of the DG with the proposed control strategy is analyzed by bode diagrams. Finally, simulation and experimental results verify the proposed control strategy.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.111-118
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• 2017

The increased diversity of different types of energy sources requires moving towards smart distribution networks. This paper proposes a probabilistic DG (distributed generation) units planning model to determine technology type, capacity and location of DG units while simultaneously allocating ESS (energy storage systems) based on pre-determined capacities. This problem is studied in a wind integrated power system considering loads, prices and wind power generation uncertainties. A suitable method for DG unit planning will reduce costs and improve reliability concerns. Objective function is a cost function that minimizes DG investment and operational cost, purchased energy costs from upstream networks, the defined cost to reliability index, energy losses and the investment and degradation costs of ESS. Electrical load is a time variable and the model simulates a typical radial network successfully. The proposed model was solved using the DICOPT solver under GAMS optimization software.

• 한국전자파학회논문지
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• 제18권7호
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• pp.834-838
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• 2007

본 논문에서는 DGS 사이의 거리를 좁힌 C-DGS(Coupled-Defected Ground Structure)를 제 안하고, 이를 이용하여 차단 특성이 향상된 BSF(Bandstop Filter)를 제안하였다. 제안된 C-DGS는 각 DGS가 가지고 있는 인덕턴스 성분에 자계 결합을 발생시켜, 주기적인 구조를 가진 DGS와 비교해서 차단 특성이 향상된다. 또한, 제안된 C-DGS를 기존 보고된 양면 BSF에 적용시킨 새로운 BSF를 제작 및 측정하였다. C-DGS를 이용한 BSF는 3.8 GHz에서 15.5 GHz의 -20 dB 저지 대역을 가지며, 차단 특성은 110.8 dB/GHz로 기존 양면 대역 저지 여파기와 비교해서 차단 특성을 7.6배 향상시켰다. 제안된 C-DGS는 DGS를 이용한 고성능 여파기 설계에서 유용하게 적용될 수 있을 것이다.

• 한국전자파학회논문지
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• 제18권11호
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• pp.1291-1298
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• 2007

종래의 DGS를 이용한 초고주파 회로의 메탈 패키징(metal packaging)시 존재했던 DGS의 접지면 접촉 문제를 해결하고자, 본 논문에서는 이중 기판 결함 접지 구조 구조를 제안하고, 이를 1:4 비대칭 전력 분배기에 적용한 응용예를 제시한다. 이중 기판에 구현된 사각형 DGS는 종래와 같이 마이크로스트립 선로의 특성 임피던스를 표준형 선로보다 크게 증가시킨다. 이중 기판 DGS 구조를 형성하기 위하여 제2유전체 기판이 DGS가 구현된 기판면의 바닥 접지면에 접합된다. 따라서 제2유전체 기판이 메탈 패키지 바닥면에 장착되므로, DGS가 직접 패키지 접촉되는 것을 막을 수 있다. 초고주파 회로 응용예를 보이기 위해, 이중 기판 DGS를 이용하여 패키지 접지 문제를 해결한 1:4 비대칭 전력 분배기의 설계 및 측정 결과가 제시되는데, 시뮬레이션과 측정 결과에 있어서 잘 일치하는 특성을 보인다.

• 한국전문물리치료학회지
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• 제29권3호
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• pp.225-234
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• 2022

Background: Trunk movements are an important factor in activities of daily living; however, these movements can be impaired by stroke. It is difficult to quantify and measure the active range of motion (AROM) of the trunk in patients with stroke. Objects: To determine the reliability and validity of measurements using a digital goniometer (DG) and smart phone (SP) applications for trunk rotation and lateral flexion in stroke patients. Methods: This is an observational study, in which twenty participants were clinically diagnosed with stroke. Trunk rotation and lateral flexion AROM were assessed using the DG and SP applications (Compass and Clinometer). Intrarater reliability was determined using intraclass correlation coefficients (ICCs) with 95% confidence intervals. Pearson correlation coefficient was used to determine the validity of the DG and SP in AROM measurement. The level of agreement between the two instruments was shown by Bland-Altman plot and 95% limit of agreement (LoA) was calculated. Results: The intrarater reliability (rotation with DG: 0.96-0.98, SP: 0.98; lateral flexion with DG: 0.97-0.98, SP: 0.96) was excellent. A strong and significant correlation was found between DG and SP (rotation hemiplegic side: r = 0.95; non-hemiplegic side: r = 0.90; lateral flexion hemiplegic side: r = 0.88; non-hemiplegic side: r = 0.78). The level of agreement between the two instruments was rotation (hemiplegic side: 23.02° [LoA 17.41°, -5.61°]; non-hemiplegic side: 31.68° [LoA 23.87°, -7.81°]) and lateral flexion (hemiplegic side: 20.94° [LoA 17.48°, -3.46°]; non-hemiplegic side: 27.12° [LoA 18.44°, -8.68°]). Conclusion: Both DG and SP applications can be used as reliable methods for measuring trunk rotation and lateral flexion in patients with stroke. Although, considering the level of clinical agreement, DG and SP could not be used interchangeably for measurements.

• 한국환경보건학회지
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• 제35권6호
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• pp.478-485
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• 2009

This study was performed to assess airborne fungi concentrations during fall in eight subway stations in Seoul, Korea. The purpose of this study was to investigate appropriate culture media and evaluate factors affecting airborne fungi concentrations. Results indicated that airborne fungi concentrations showed log-normal distribution. Thus, geometric mean (GM) and geometric standard deviation (GSD) were calculated. The GM of airborne fungi concentrations cultured on malt extract agar (MEA) media was 466 $cfu/m^3$ (GSD 3.12; Range 113~4,172 $cfu/m^3$) and the GM of concentrations cultured on DG18 media was 242 $cfu/m^3$ (GSD 4.75; Range 49~6,093 $cfu/m^3$). Both of GM values exceeded 150 $cfu/m^3$, the guideline of World Health Organization (WHO). There was no significant difference between two fungi concentrations cultured on MEA and DG18 media, respectively. Two factors, such as relative humidity and depths of subway stations were significantly related to airborne fungi concentrations. It is recommended that special consideration should be given to deeper subway stations for improvement of indoor air quality.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8431-8438
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• 2016

Doxorubicin (DOX) was introduced as an effective chemotherapeutic for a wide range of cancers but with some severe side effects especially on myocardia. 2-Deoxy-D-glucose (2DG) enhances the damage caused by chemotherapeutics and ionizing radiation (IR) selectively in cancer cells. We have studied the effects of $1{\mu}M$ DOX and $500{\mu}M$ 2DG on radiation induced cell death, apoptosis and also on the expression levels of p53 and PTEN genes in T47D and SKBR3 breast cancer cells irradiated with 100, 150 and 200 cGy x-rays. DOX and 2DG treatments resulted in altered radiation-induced expression levels of p53 and PTEN genes in T47D as well as SKBR3 cells. In addition, the combination along with IR decreased the viability of both cell lines. The radiobiological parameter (D0) of T47D cells treated with 2DG/DOX and IR was 140 cGy compared to 160 cGy obtained with IR alone. The same parameters for SKBR3 cell lines were calculated as 120 and 140 cGy, respectively. The sensitivity enhancement ratios (SERs) for the combined chemo-radiotherapy on T47D and SKBR3 cell lines were 1.14 and 1.16, respectively. According to the obtained results, the combination treatment may use as an effective targeted treatment of breast cancer either by reducing the single modality treatment side effects.

• 실내환경 및 냄새 학회지
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• 제16권1호
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• pp.47-53
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• 2017

Mold is one of the important bio-aerosols affecting human health in the indoor environment. To manage mold contamination, it is necessary to use an appropriate method for its detection and enumeration. Recently, the impaction method of ISO 16000-18 has been established as one of methods to detect and enumerate molds in air. To investigate the general use of the impaction method for mold detection in domestic indoor environments, the suitability of the method was assessed using different antibiotics, media and air samplers. All of the three antibiotics tested - ampicillin, chloramphenicol and streptomycin - showed inhibitory effects on bacterial colony formation on MEA and DG-18 media, without inhibiting mold growth. Of these three antibiotics, ampicillin was the most effective. There was no statistical difference between MEA and DG-18 media in the measurement of mold concentration. The formation of discriminative colony morphology was more apparent in DG-18 media. No significant difference in the measurement of mold concentration was found between Andersen samplers and MAS-100NT samplers, which are two major samplers introduced in Korea.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.118-123
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• 2004

분산전원의 단독운전 검출에 관한 기존의 연구들은 사고위치에 따른 다양한 상황을 고려하지 않고 조건들만 만족되면 분산전원측을 무조건 분리시켰다. 하지만 분산전원이 연계되어 있지 않은 인근선로사고의 경우에는 인근선로측 보호기기의 동작으로 전원 측으로부터 정상적인 전원이 공급되기 때문에 분산전원을 분리시킬 필요가 없다. 또한 연계선로 사고의 경우일지라도 분산전원이 즉시 분리돼야 하는 경우인지, 단독운전인지, 정상운전의 경우인지 과부하차단에 의한 보호기기 동작의 경우인지를 고려해야 한다. 본 논문에서는 이러한 고려사항들을 계통의 전력상태 변화를 통해 구분하고 단독운전 시 및 분산전원을 분리해야 되는 상황을 찾아서 분산전원을 분리시키는 단독운전 상태 검출 알고리즘을 제안하였다. 고립운전 상태 검출 알고리즘을 검증하기 위하여 PSCAD/EMTDC를 이용하여 사례별로 시뮬레이션을 수행하였다.