• 전력전자학회논문지
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• 제25권4호
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• pp.311-318
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• 2020

A photovoltaic (PV) system uses an AC module integrated converter (MIC) to operate PV cells at a maximum power point (MPP) and for high efficiency. The MPP of a PV cell varies depending on partial shading conditions, and loss occurs differently according to the configuration method of the PV-MIC. Therefore, this study compares the losses of passive components and power semiconductors according to the partial shading conditions of the PV module. Theoretical loss analysis is performed using parameters for the datasheet and PSIM simulation results. Analysis results verify that the one-stage PV-MIC demonstrates high efficiency.

• KIEAE Journal
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• 제14권2호
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• pp.21-28
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• 2014

This paper provides the up to date review of the shading effects on PV module performance and the associated detection algorithm related to the maximum power point tracking. It includes the brief explanations of the MMP variations due to the shading occurrence on the PV modules. Review of experimental and simulation studies highlighting the significant impacts of shading on PV efficiencies were presented. The literature indicates that even the partial shading of a single cell can greatly drop the entire module voltage and power efficiency. The MMP tracking approaches were also reviewed in this study. Both conventional and advanced soft computing methods such as ANN, FLC and EA were described for the proper tracking of MMP under shaded conditions. This paper would be the basic source and the comprehensive information associated with the shading effects and relevant MPP tracking technique.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.785-788
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• 2003

In this paper , the simple MPPT(Maximum Power Point Tracking) control algorithm is proposed for the grid-connected photovoltaic power system. This method uses the difference in the slope of the solar array voltage range below the MPP and above the MPP. This simple the algorithm enables the hardware implementation achieved by only analog devices. The proposed MPPT algorithm is verified by the hardware experiment using 500[W] solar away simulator, simplified inverter model hardware set, and rectified grid-line.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.234-235
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• 2013

PV cell model은 PV simulator를 제작하거나 시뮬레이션 Software를 통하여 PV 발전시스템을 분석하기 위하여 필요하다. PV cell의 I-V 특성곡선은 PV cell의 특성을 결정짓는 중요한 요소이며, 전기적으로 다이오드정수($I_o$, $v_t$)와 광전류원($I_{ph}$) 그리고 직렬저항($R_s$) 및 션트저항($R_{sh}$)으로 모델링 가능하다. 광 전류원은 일사량에 비례하여 그 값을 추정할 수 있으나 나머지 변수인 다이오드정수($I_o$, $v_t$)와 직렬저항($R_s$) 및 션트저항($R_{sh}$)은 제조사 데이터시트에서 제공하는 3개의 대표적인 운전점인 개방회로 전압($V_{oc}$), 단락회로 전류($I_{sc}$), 그리고 최대출력에서의 전압/전류($V_{MPP}/I_{MPP}$)를 기초로 수학적으로 해를 구하여야만 한다. 본 논문에서는 저자가 제안하는 K-알고리즘의 수학적 도출 과정과 수치해석적 특성을 고찰한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (B)
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• pp.118-120
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• 2005

본 논문은 모양 특성을 이용한 효과적인 식물 잎 이미지 검색 시스템을 제시한다. 잎 이미지의 더 효과적인 표현을 위해 개선된 MPP 알고리즘을 제안하고, 매칭에 소요되는 시간을 줄이기 위해 기존의 Nearest Neighbor(NN) 검색을 수정한 동적인 매칭 알고리즘을 제시한다. 특히, 더 나은 정확율과 효율성을 위해, 잎 모양과 잎차례를 스케치하여 질의할 수 있도록 하였다. 실험에서는 제안한 알고리즘과 기존의 알고리즘인 Fourier Descriptor, Moment Invariants, MPP와 비교하였다. 1000여개의 식물 잎 이미지를 통한 실험결과는 제안한 방법이 기존의 기법보다 더 좋은 성능임을 보였다.

• Journal of Power Electronics
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• 제7권2호
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• pp.174-180
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• 2007

In this paper, a simple control method for two-stage utility grid-connected photovoltaic power conditioning systems (PCS) is proposed. This approach enables maximum power point (MPP) tracking control with post-stage inverter current information instead of calculating solar array power, which significantly simplifies the controller and the sensor. Furthermore, there is no feedback loop in the pre-stage converter to control the solar array voltage or current because the MPP tracker drives the converter switch duty cycle. This simple PCS control strategy can reduce the cost and size, and can be utilized with a low cost digital processor. For verification of the proposed control strategy, a 2.5kW two-stage photovoltaic grid-connected PCS hardware which consists of a boost converter cascaded with a single-phase inverter was built and tested.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2012년도 심포지엄 및 춘계학술발표회
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• pp.177-178
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• 2012

• 한국환경생태학회지
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• 제25권2호
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• pp.235-246
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• 2011

최근 자연공원 내 케이블카 설치에 대한 타당성 여부를 놓고 찬반 그룹 간에 논쟁이 뜨겁다. 본 연구는 인구사회학적 특성 및 방문경험과 자연과의 유대와의 관계, 자연과의 유대와 케이블카 설치로 인한 결과(사회, 경제, 생태적)에 대한 신념 및 케이블카 설치 지지도와의 관계를 조사하였다. 자료수집은 2010년도 9월 중 총 134명의 무등산도립공원 방문객을 대상으로 현지설문조사를 통해 이루어졌다. 자연과의 유대는 Mayer and Frantz(2004)의 "자연과의 유대척도"를 수정한 척도를 이용하여 측정하였다. 자연과의 유대는 요인분석 결과 2개의 요인, 즉 '상호의존적', '독립적' 요인으로 구분되었다. 응답자의 연령, 교육수준, 무등산도립공원 방문횟수 및 무등산 중봉지역 방문횟수가 높아지거나 많아질수록 자연과의 유대가 증가하였다. 자연과의 유대가 높은 응답자가 낮은 응답자에 비하여 케이블카 설치로 인한 부정적 결과에 대한 신념이 컸지만 긍정적 결과에 대한 신념과는 관계가 없었다. 자연과의 유대 수준이 높은 응답자는 낮은 응답자에 비하여 케이블카 설치에 대한 지지도가 낮게 나타났다.

• International journal of advanced smart convergence
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• 제6권4호
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• pp.9-18
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• 2017

In order to respond to the ever-changing media environments in the era of smart and mobile technology, KBS has introduced and partially applied PIE-TV and PIE-nonTV modes that monitor the average number of viewers among the national population group by means of the sample household extraction method which is a traditional way of rating investigation. This study analyzes the correlation between the number of viewers of premiere, re-air broadcasting, and MPP channel programs and the number of OTT-based VOD viewers in reference to the data extracted from PIE-TV survey results. KBS conducted a survey for 3 months between June and August 2017 to measure the PIE-TV Index, based on which the above-mentioned correlation was analyzed with programs classified to entertainment, drama, and cultural programs. For data analysis, SPSS (Ver. 18.0 for Window, SPSS Inc, Chicago, IL, USA) was utilized. It was assumed that when p<0.05 in the confidence interval of 95%, statistically significance would be secured. Among the 30 subjects in the simple correlation analysis, the parameter was determined by the Person correlation coefficient and the non-parameter by the Spearman correlation coefficient. Analysis results are as below: (1) As the number of viewers of premier entertainment, drama, and cultural programs was larger, the number of VOD viewers was larger accordingly. (2) As for entertainment and drama programs, as the number of re-air broadcasting viewers was larger, the number of VOD viewers decreased accordingly. (2) As for entertainment and drama programs, as the number of MPP viewers was larger, the number of VOD viewers decreased accordingly. It is expected that this statistical data can be utilized for strategic planning of MPP channel lineups including terrestrial TV broadcasting, cable TV, etc.

• 동의신경정신과학회지
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• 제23권1호
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• pp.129-143
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• 2012

Objectives : To evaluate the neuroprotective effects of the essential oil from Sohaphwangwon (SH), a Chinese traditional medicinal prescription in a Parkinson's disease mouse model. Methods : 1. The neuroprotective effect of SH on primary neuronal cells was examined by using 1-methyl-4-phenylpyridinium ion (MPP+). 2. The neuroprotective effect of SH was examined in a Parkinson's disease mouse model. C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days. SH inhalation was applied before MPTP treatment for 7 days and continued until 12 days after the first MPTP treatment. 3. To find out the intracellular target signal molecule(s) regarding the neuroprotective effect of SH essential oil, brain-derived neurotropic factor (BDNF) and synaptic protein SNAP25 were examined by Western blot analysis. Results : 1. MPP+ induced a concentration-dependent decrease in cell viability. However, in the presence of 3 and 5 ug/ml of SH, MPP+-induced cell death was significantly reduced. 2. SH inhalation in MPTP mice led to the restoration of behavioral impairment and rescued tyrosine hydroxylase (TH)-positive dopaminergic neurodegeneration. 3. In SH / MPTP mice, BDNF and SNAP25 increased. Conclusions : This experiment suggests that the neuroprotective effect of SH essential oil is mediated by the expression of BDNF. Furthermore, SH essential oil may serve as a potential preventive or therapeutic agent regarding Parkinson's disease.