• 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".

• 한국멀티미디어학회논문지
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• 제18권12호
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• pp.1432-1438
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• 2015

We present a methodology to detect moving shadows in video sequences, which is considered as a challenging and critical problem in the most visual surveillance systems since 1980s. While most previous moving shadow detection methods used hand-crafted features such as chromaticity, physical properties, geometry, or combination thereof, our method can automatically learn features to classify whether image segments are shadow or foreground by using a deep learning architecture. Furthermore, applying Markov Random Field enables our system to refine our shadow detection results to improve its performance. Our algorithm is applied to five different challenging datasets of moving shadow detection, and its performance is comparable to that of state-of-the-art approaches.

• 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.

• 한국경영과학회지
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• 제18권2호
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• pp.147-156
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• 1993

Recently a new concept of shadow prices, called average shadow price, has been developed. This paper provides a dual problem and the corresponding duality theorems justifying this new shadow price. The general duality framework is used. As an important secondary result, a new reduced class of price function, the pp. h.-class, has been developed for the general duality theory. This should be distinguished from other known reductions achieved in some specific areas of mathematical programming, in that it sustains the strong duality property in all the mathematical programs. The new general dual problem suggested with this pp. h.-class provides, as an optimal solution, the average shadow prices.

• 한국IT서비스학회지
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• 제21권6호
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• pp.91-116
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• 2022

This research shows how the perception of digital shadow work varies depending on the user's period of use of digital services in applications, which are key areas of digital services. The purpose of this research is to investigate how the digital shadow work type changes over time. This research adopted a qualitative research method for location-based service "help application" users and examined the change in perception from the app service acceptance stage to the app service continuous use stage with two-times interviews of ten users by a longitudinal research design. This study conducted a longitudinal analysis focusing on how digital shadow work occurs in the application subscription process, exploring phenomenologically how the type changes throughout the process over time.

• 한국정밀공학회지
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• 제21권8호
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• pp.152-156
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• 2004

A new tool of surface patterning technique for general purpose lithography was developed based on shadow mask method. This paper describes the fabrication of a new type of miniaturized shadow mask. The shadow mask is fabricated by photolithography and etching of 100-mm full wafer. The fabricated shadow mask has over 388 membranes with apertures of micrometer length scale ranging from 1${\mu}{\textrm}{m}$ to 100s ${\mu}{\textrm}{m}$ made on each 2mm${\times}$2mm large low stress silicon nitride membrane. It allows micro scale patterns to be directly deposited on substrate surface through apertures of the membrane. This shadow mask method has much wider choice of deposit materials, and can be applied to wider class of surfaces including chemical functional layer, MEMS/NEMS surfaces, and biosensors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.402-406
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• 1995

The shadow moire is one the optical techniques which able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a grating and its shadow projected on the surface of an object. But in the conventional shadow moire method the reference grating and deformed grating are mutually dependent, it is impossible to obtain uniform phase shifts on the whole field by moving the reference grating. Here we propose ane trial to apply phase shifting to conventional shadow moire. When, in the conventional arrangement, Phase-shifting that is sctually constant regardless of fringe orders is achieved by moving the grating and the light source. Finally we obtained a better result by using this procedure and applied the phase shifting shadow moire to three dimensional measurement.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.371-374
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• 2008

In very high-spatial resolution remote sensing imagery, it is difficult to extract the feature information of various objects because of occlusion and shadows. Moreover, various and feeble information within shadows can be of use in GIS-based applications and remote sensing analysis. In this paper, we developed a radiometric restoration method for shadow areas using KOMPSAT-2 satellite image. After detecting the shadow, non-shadow pixels nearby are extracted using a morphological filter. An iterative linear regression method is applied to calculate the relationship between shadow and non-shadow pixels. The shadows are restored by the parameters of the linear regression algorithm. Tests show that recovery of shadowed areas by our method leads to improved image quality.

• 한국전자통신학회논문지
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• 제4권3호
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• pp.204-210
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• 2009

영상 감시 분야 중 침입자를 자동으로 인식해 내는 기술의 전처리 과정인 배경 분리 방법과 이동하는 객체의 주변에 있는 그림자를 제거하는 방법에 대한 많은 연구가 있어 왔다. 이동하는 객체와 그림자의 분리가 정확하지 않을 경우 이동 객체의 정확한 형태 분석이 어려우며, 위치 추적 또한 어렵다. 본 논문에서는 그림자를 제거하는 방법으로 명도 값을 활용하는 방법을 제안한다. 그림자 영역이 배경 영역과 비교하여 색상의 변화는 발생하지 않고, 명도 차이만 발생한다는 점에 착안한 방법으로, 이전 프레임에서 그림자 제거에 사용했던 임계값을 다음 프레임에서 갱신하여 사용하는 방법이다.

• 복식
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• 제64권7호
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• pp.82-96
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• 2014

This study views the shadows cast by the light and a subject provides new interpretations rather than it simply being an additive product. Particularly in fashion photograph, light and shadows are often used as tools to convey meaning. Accordingly, this study aims to classify the utilization of the shadow created by light and deriving its expressive characteristics in fashion photograph. To achieve these research aims, literature and case studies were conducted. The results are as follows. First, the shadows were mainly focused on a subject. Secondly, shadows caused by lighting is casted directly into the inside of the main subject in a frame takes a role of omission or emphasis. Third, shadows caused by a second unseen object outside the frame are utilized with the main subject in the frame. Based on these results above, spatial third dimensionality, optical illusion and accentuation were derived as expressive characteristics of the shadow in fashion photograph. As such, in fashion photograph, shadow is an important element for photographers. The variability of the shadow makes it possible for creative changes as its amount, angle and direction can be altered by adjusting the light in accordance with the intention of the artist. Therefore, its utilization methods will be diversified hereafter. Accordingly, it is required to recognize that shadow may be recreated as an independent object in fashion photograph.