• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.993-1002
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• 2022

This paper relates to a method of modeling the thrust dynamic load caused by the thrust variation occurring on the blade due to the tower shadow below the rated wind speed. A method that uses thrust coefficient is presented by introducing "tower shadow coefficient of thrust variation". For a 2MW wind turbine, the values of "tower shadow coefficient of thrust variation" are calculated and analyzed at wind speeds below the rated. The dynamic load model of thrust under tower shadow is evaluated in Matlab/Simulink using the obtained "tower shadow coefficient of thrust variation" and thrust coefficient. It shows that the thrust variations acting on the three blades by the tower shadow can be expressed using both the thrust coefficient and the introduced "tower shadow coefficient of thrust variation".

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.348-352
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• 2008

Deformation of the shadow mask is one of the problems encountered during the deposition of organic materials for manufacturing large size organic light emitting diode (OLED). The larger the glass substrate, the larger the shadow mask becomes. As the size of the shadow mask increases, its deformation becomes more severe, thereby making it difficult to deposit organic materials in a precise pattern on a substrate. In this paper, a new method for reducing drooping of the shadow mask for large size OLED vapor depositions is proposed. The proposed shadow mask with cross stripe wires has higher stiffness than the pure shadow mask, which results in reducing drooping of the shadow mask. A commercial FEM program, ANSYS, is used for the evaluation of the proposed shadow mask. The analysis showed that the shadow mask with cross stripe wires have an effect on reducing drooping about 18.6% or more.

• 한국ITS학회 논문지
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• 제7권1호
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• pp.32-41
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• 2008

비디오를 이용한 비전기반 감시에서 움직이는 객체의 추적은 GMM (Gaussian Mixture Model)을 사용한 배경영상과 현재영상의 차이법을 이용한다. 문턱치를 통해 생성된 이진영상을 이용하여 객체 추적을 할 경우 객체 정보가 아닌 그림자에 의하여 객체가 병합되는 현상이 나타난다. 본 논문에서는 신경망(Backpropagation Neural Network)을 이용하여 그림자를 제거하는 방법을 제안하였다. 10개의 동영상에서 객체영역과 캐스트그림자(Cast-Shadow)영역의 훈련용 이미지에서 특징 값을 추출하여 신경망을 훈련시켰다. 캐스트그림자를 제거하는 방법은 이진영상의 객체로 추정되는 영역에서 그림자를 분리하는 방법을 기초로 하며 기존의 그림자 제거 알고리즘 (SNP, SP, DNM1, DNM2, CNCC)보다 그림자 제거 성능이 (16.2%, 38.2%, 28.1%, 22.3%, 44.4%)로 높게 나타났다.

• 한국IT서비스학회지
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• 제15권3호
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• pp.33-50
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• 2016

In a dynamic IT environment, employees often utilize external IT resources to work more efficiently and flexibly. However, the use of external IT resources beyond its control may cause difficulties in the company. This is known as "Shadow IT." In spite of efficiency gains or cost savings, Shadow IT presents problems for companies such as the outflow of enterprise data. To address these problems, appropriate measures are required to maintain a balance between flexibility and control. Therefore, in this study, we developed a new information security management system called AIIMS (Advanced IT service & Information security Management System) and the Shadow IT Evaluation Model. The proposed model reflects a Shadow IT's attributes such as innovativeness, effectiveness, and ripple effect. AIIMS consists of five fields: current analysis; Shadow IT management plans; management process; education and training; and internal audit. There are additional management items and sub-items within these five fields. Using AIIMS, we expect to not only mitigate the potential risks of Shadow IT but also create successful business outcomes. Now is the time to draw to the Light in the Shadow IT.

• 정보처리학회논문지B
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• 제15B권6호
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• pp.527-532
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• 2008

본 논문은 그림자의 기하학 정보와 광원의 종류 및 방위에 관계없이 그림자 밝기가 점진적으로 변하거나 변화가 없다는 가정과 그림자는 어둡다는 공리를 기반으로 임의의 복잡한 자연 영상에서 그림자를 검출하는 기법을 제안한다. 먼저, 전처리를 통하여 그림자 후보영상을 검출한다. 다음으로, 인접화소들 사이의 선형독립성을 낮추기 위하여 유사 밝기를 대표 밝기로 표현하는 균일 양자화를 수행한다. 마지막으로, 그림자 밝기의 선형적 변화 특성을 이용하여 선형독립성이 낮은 그림자를 검출한다. 임의의 단일 자연영상의 실험에서, 제안한 알고리즘은 본영과 단색 배경을 갖는 반영 및 셀프그림자의 검출에 강건함을 보였다.

• 한국정보시스템학회지:정보시스템연구
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• 제31권3호
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• pp.89-108
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• 2022

Purpose The purpose of this study is to clarify the conceptualizations of mandatory and reward that have come into focus in the definition of digital shadow work. And explore how users in a shared services environment view cost and coercion from the perspective of digital shadow work. Design/methodology/approach We conducted one-on-one interviews with 4 participants, with each interview being an average of 25 minutes. Based on literature review, stakeholder observation, and interviews on digital shadow work so far, very objective results can be derived through triangulation based on the basis of multiple sources. Findings According to the results of the preliminary study, there are some rewards for each type of digital shadow work, but time saving and service convenience are considered more than financial rewards. Unfair demands in determining whether to implement them in consideration of the difficulty and expected benefits of the demanding digital work can cause dissatisfaction with the service. Academic implications and future research directions are also discussed.

• 디지털콘텐츠학회 논문지
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• 제19권1호
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• pp.165-171
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• 2018

그림자는 자연 영상에서 관찰되는 물리적인 현상으로 지능형 비디오 감시, 교통 감시 및 항공 영상 분석 등과 같은 다양한 영상처리 시스템에 부정적인 영향을 미치는 요소이다. 따라서 그림자의 검출은 컴퓨터 비전의 전 분야에서 전처리 과정으로 고려되어야 한다. 본 논문에서는 참조 영상이 필요 없는 단일 자연 영상에서 그림자 검출을 위한 다양한 특징 요소들을 정의하고 분석하였다. 그림자 요소들은 영상의 밝기, 색도, 조도불변, 색상불변 및 정보의 불확실성을 의미하는 엔트로피 영상 등을 기술하였으며, 분석 결과 색도와 조도불변 영상이 그림자 검출 및 복원에 효과적임을 알 수 있었다. 향후 다양한 그림자 특징 요소들의 퓨전 맵을 정의하고, 다양한 조명 수준에 적응 가능한 그림자 검출 및 색도와 조도불변 영상을 이용한 그림자 제거 연구를 계속하고자 한다.

• 전기학회논문지
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• 제57권6호
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• pp.994-1002
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• 2008

In this paper a novel tracking system is described, regarding the influence of shadow between array, aimed at improving the efficiency of PV tracking system. Comparing with a building site versus capacity power, domestic solar powers have a limited siting. Therefore, each array interferes with the shadow of other arrays. The loss by influence of those shadow can be compensated for by means of control algorithm of the tracking device. The paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. By using an azimuth of current solar position and the length between arrays, the controller of tracking device is able to calculate the length between actual arrays and make a comparison of the shadow length at a specific time with the length between arrays. When the shadow length is longer than the length between arrays, the controller of tracking device can adjust a position by compensating error altitude of the length between arrays at an altitude of current solar position. In the paper, we develop the control algorithm able to minimize the loss caused by the influence of shadow on the PV tracking system, and compared this with conventional output system. The controller has been tested in the laboratory with proposed algorithm and shows excellent performance.

• The Journal of Asian Finance, Economics and Business
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• 제8권11호
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• pp.41-46
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• 2021

The purpose of this study is to investigate the relationship between unemployment and shadow economy for 7 selected ASEAN countries using panel data from 2000-2017. This study uses a sample of 7 ASEAN countries including Cambodia, Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam covering the 2000-2017 period. The stationarity of the variables is determined by Pesaran panel unit-root tests. The Westerlund panel co-integration technique is used to examine the long-run relationship among the variables. In addition, dynamic ordinary least squares (DOLS) and fully modified ordinary least squares (FMOLS) methods are also employed. The DOLS and FMOLS results indicate that unemployment acts as an important driver for the increase in the shadow economy. In addition, the study results also reveal that GDP per capita has a negative impact on the shadow economy. Moreover, government expenditure, bank credit, and inflation are positively related to the shadow economy. The empirical results indicate that the size of the shadow economy is boosted by unemployment in the selected ASEAN economies. In addition, it is also evident that an increase of GDP per capita in the sample countries results in a lower shadow economy. Besides, government expenditure, bank credit, and inflation play a crucial role in the shadow economy.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.487-490
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• 2004

In order to simulate OLED evaporation process, modeling of directional distribution of the vaporized organic materials, film thickness distribution profile and pattern-mask shadow effect are required In accordance with many literatures; all of them except shadow effect modeling are studied and developed. In this paper, modeling algorithm of evaporation shadow is presented for process simulation of full-color OLED evaporating system. In OLED evaporating process the offset position of the point cell-source against the substrate rotation axis and the usage of the patterned mask are the principal causes for evaporation shadow. For geometric simulation of shadow using z-map, the film thickness profile, which is condensed on a glass substrate, is converted to the z-map data. In practical evaporation process, the glass substrate is rotated. This physical fact is solved and modeled mathematically for z-map simulation. After simulating the evaporation process, the z-map data can present the shadow-effected film thickness profile. Z-map is an efficient method in that the cross-sectional presentations of the film thickness profile and thickness distribution evaluation are easily and rapidly achieved.