• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.556-563
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• 2020

Most of a BIPVS (Building Integrated Photovoltaic System) is installed on the rooftop or wall of a building. Therefore, the main factor to consider for selecting the installation site is the shadow effects produced by the surrounding buildings. On the other hand, when the photovoltaic was installed on soundproof walls, shadow effects were produced by not only surrounding buildings but also the surrounding trees. Therefore, a different data model and algorithm with the BIPVS case are essential for proper installation sites selection of a SIPVS (Soundproof wall Integrated Photovoltaic System). This paper deals with the DSM (Digital Surface Model)-based proper installation site analysis for SIPVS. First, the solar incident and altitude angles of the installation candidate sites (solar panel) during the year were calculated. Second, the shadow effects (shadowed or unshadowed) were determined for the candidate sites at each time with the DSM. Third, the amount of solar radiation was calculated with the incident angle for the candidate sites at an unshadowed period. The proper installation site of the SIPVS could then be selected by comparing the accumulated annual solar radiation for each candidate. The proposed algorithm was implemented as a prototype (Java program). From the experiment, the order of the installation suitability was determined among the nine candidates. The proposed algorithm could be used for proper BIPVS installation site analysis aimed at the lower part of a building and calculation of the expected power production.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.75-76
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• 2014

This study deals with a isolation type MIC(Module Integrated Converter) for AC module with advantages such as DC Wireless, freely selectable installation capacity, minimized shadow effect etc. In this paper, MIC circuit with the function which can remove the ripple voltage of PV module and give the discharging path for charged energy in leakage inductance of isolation transformer. The validity of proposed circuir is verified by the simulation with PSIM.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.5
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• pp.275-281
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• 2009

The microstructure of copper films prepared by a sputtering apparatus, which was fabricated to enhance the shadowing effect, was investigated by scanning electron microscopy. Black copper films were deposited on copper wires at an Ar pressure of 10 Pa. The black films had an extremely porous structure composed of separated columns. This structure is quite similar to that of black titanium films prepared by cylindrical magnetron sputtering. These results suggest that the porous structure composed of separated columns is easily formed for metal films by enhancing the shadowing effect.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.617-624
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• 2008

This paper proposes design and implementation of wind turbine simulators which incorporate the turbine dynamic characteristics. At first, the turbine output characteristic in steady state is modelled as a function of wind speed and then dynamic characteristics are modelled such as pitch angle control, torsional vibration, tower shadow effect, wind shear effect, and inertia effect. In addition, a wind speed simulator is developed which can generate the real wind speed pattern. The wind turbine simulator is implemented with 3[kW] M-G set(cage-type induction motor coupled with doubly-fed induction generator) at laboratory.

• Journal of the Korea Computer Graphics Society
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• v.7 no.2
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• pp.11-19
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• 2001

This paper proposes a colored paper mosaic rendering technique based on image segmentation that can automatically generate torn and tagged colored paper mosaic effect. and 3D effect that come about in human-made mosaic work can be represented by generating shadow using difference of paper thickness. Previous method did not produce satisfactory results due to the ineffectiveness of having to use pieces of the same size. The proposed two methods for determination of paper shape and location that are based on segmentation can subdivide image area by considering characteristics of image. The first method is to generate Voronoi polygon after subdividing the segmented image again using quad tree. And the second method is to apply the Voronoi diagram on each segmentation layer. Through these methods, the characteristic of the image is expressed in more detail than previous colored paper mosaic rendering method and these methods enable to produce image that is closer to human-made mosaic work.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1022-1027
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• 1999

This paper proposes method that uses Time-Difference-of-Arrival(TDOA) of Forward Pilot signals from base stations(BS) arriving at a mobile station(MS) as a position location method of CDMA MS. MS searcher does acquisition of BS Pilot signals and measurement of TDOAs. In order to do it, its processing gain is very important. Proportional relationship of the gain to the signal coherent integration interval is theoretically derived and analyzed and field test is performed to show acquisition of weak Pilot signals and stable measurements of TDOA values by increasing the gain. Also, signal strength decrease exponentially by the distance it travels. Therefore, improvement of the searcher gain makes possible to acquire Pilot signals at a location far away from BS. Variation of possible position estimation area relative to the signal strength within a cell is simulated with computer. Neglecting shadow effect it indicated necessity of detecting signals below -35dB in order to cover over 90% of cell area. Thus, efforts to maximize searcher coherent integration interval in order to acquire weak Pilot signals are required for expansion of position estimation area and measurement of stable TDOA values.

• Journal of the Korean earth science society
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• v.31 no.7
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• pp.738-748
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• 2010

In order to clarify the impact of variation of albedo on the atmospheric boundary layer caused by the density of building in urban areas, both satellite data analysis and numerical experiments were carried out. Utilized satellite data were multi-spectral visible data detected by the Korea Multi- Purpose Satellite -2 (KOMSAT-2), and the numerical models for the estimation of surface heat budget are Albedo Calculation Model (ACM) and Oregon State University Planetary Boundary Layer model (OSUPBL). In satellite data analysis, the estimated albedo in densely populated building area is lower than other regions by 17% at the maximum due to the shadow effect of skyscraper buildings. The surface temperature reached $43.5^{\circ}C$ in the highly dense and tall building area and $37.4^{\circ}C$ in the coarse density area of low buildings, respectively. However, the low albedo in densely integrated building area is not directly related to the increase of surface air temperature since the mechanical turbulence induced by the roughness of buildings is more critical in its impact than the decrease of albedo.

• Knowledge Management Research
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• v.24 no.3
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• pp.173-193
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• 2023

Digital transformation and the COVID-19 pandemic have facilitated the rapid development and dissemination of non-face-to-face technologies such as self-service technologies (SSTs). This research investigates how motivation factors affect consumers' negative responses to digital shadow work (DSW) in SSTs which decreases their continuous use intention of SSTs. Also, we examine whether the grafication delay ability moderates the relationship between consumers' negative responses to DSW and their continuous use intention of SSTs. By an analysis of usable 450 user respondents via SmartPLS 4.0, perceived benefits was found to significantly influence consumers' negative responses to DSW. Also, consumers' negative responses to DSW can significantly decrease their intention to continue using SSTs. Further, the effect of negative responses to DSW on continuous use intention of SSTs is stronger in case of consumers with low gratification delay ability than in case of consumers with high gratification delay ability. The study findings contribute to providing some strategies for companies operating SSTs by examining the effects of consumer's responses to DSW and gratification delay ability on the continuous usage intention of SSTs.

• Journal of Information Display
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• v.2 no.4
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• pp.46-51
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• 2001

Using ray-optics code incorporated with three-dimensional PDP cell simulation, we have analysed the energy flow in the PDP cell from the electric power input to the visible light output. Also, the visible light output profile and viewing angle distribution were obtained. We applied our code to the analysis of the barrier rib height effect on the visible light luminance and efficiency of the sustaining discharge. Although cells with higher barrier rib generate more VUV photons, less ratio of visible photons are emitted toward front panel due to the shadow effect. Thus, there exists optimal barrier rib height giving the highest visible luminance and efficiency. This kind of code can be a powerful tool in designing cell geometry.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.16-24
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• 2007

The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.