• Journal of Korean Society for Atmospheric Environment
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• v.28 no.2
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• pp.159-171
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• 2012

Aerosol direct radiative forcing (ADRF) retrieval method was developed by combining data from passive and active satellite sensors. Aerosol optical thickness (AOT) retrieved form the Moderate Resolution Imaging Spectroradiometer (MODIS) as a passive visible sensor and aerosol vertical profile from to the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) as an active laser sensor were investigated an application possibility. Especially, space-born Light Detection and Ranging (Lidar) observation provides a specific knowledge of the optical properties of atmospheric aerosols with spatial, temporal, vertical, and spectral resolutions. On the basis of extensive radiative transfer modeling, it is demonstrated that the use of the aerosol vertical profiles is sensitive to the estimation of ADRF. Throughout the investigation of relationship between aerosol height and ADRF, mean change rates of ADRF per increasing of 1 km aerosol height are smaller at surface than top-of-atmosphere (TOA). As a case study, satellite data for the Asian dust day of March 31, 2007 were used to estimate ADRF. Resulting ADRF values were compared with those retrieved independently from MODIS only data. The absolute difference values are 1.27% at surface level and 4.73% at top of atmosphere (TOA).

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.264-265
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• 2005

In this paper the conceptual design and development of a compact vertical type soft x-ray microscope is described. This x-ray microscope operates in the water window wavelength region(2.3 ${\sim}$ 4.4nm), where natural contrast between carbon(protein) and oxygen(water) allows imaging of unstained biological material their natural, hydrated environment. Until now, operational x-ray microscopes are based on synchrotron radiation sources, which limit their accessibility. Many biologists would benefit from having the x-ray microscope as a tool among other tools in their own laboratory, For this purpose we introduced the compact vertical type soft X-ray microscope with 50 nm resolution for biomedical application. The compact vertical type soft x-ray microscope is based on a laser plasma x-ray source, doubled ellipsoidal condenser reflective optics, diffractive zone plate optics and MCP coupled with CCD to record an x-ray image.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.572-579
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• 2003

By comparing the measured optical reflection spectra with calculated one by the transfer-matrix method (TMM) in epitaxial wafers for vertical-cavity surface-emitting lasers (VCSELs), we have estimated the systematic thickness errors in a simple and nondestructive way. The experimentally confirmed technique is based on the finding that the shape of the reflection spectra depends mainly on a newly defined single parameter, the effective error in the n-mirror layers, and the thickness error in the active cavity simply shifts the Fabry-Perot resonance wavelength. Also shown is that the proposed method is reliable when the relative standard deviation of the random thickness errors is less than 0.005. Because reflection spectra are routinely measured, we can easily estimate the thickness errors nondestructively with high spatial resolution.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.35-43
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• 1992

Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are "A" and "B" at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.al dispersion model.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.692-695
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• 2004

Fabrication of photosensitive carbon nanotubes paste and its post-treatment has been developed for high resolution with good electron emission uniformity. We report novel post-treatment techniques including rubber-rolling and multiple field emission cycling from which we could improve the field emission properties of printed carbon nanotubes. These techniques would be easily applicable to large area field emission display using paste of carbon nanotubes

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.427-430
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• 1995

This paper proposes a new image processing algorithm to recognize korean documents. It take out the region of syllable area from input character image, then it makes recognition of a consonant and a vowel in the character. A precision segmentation is very important to recognize the input character. The input image has 8-bit gray scaled resolution. Not only the shape but also vertical and horizontal lines dispersion graph are used for segmentation. Theresult shows a higher accuracy of character segmentation.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.602-605
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• 2006

Locating reinforcing bars, in particular to know their accurate depths and horizontal distances, is very important in radar inspection of concrete structures. By the way, it is not easy for an accurate depth and horizontal distance estimation of reinforcing bars in concrete structures by the radar test. This problem can be solved by synthetic aperture radar method. To improve the vertical and horizontal resolution of reinforcing bars in concrete, synthetic aperture radar method was examined in this study.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.7
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• pp.37-45
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• 1998

In this paper, we extracted heart region using dyamic contour model, increased the vertical resolution of heart region by proposed 2-dimensional interpolation method and visualized the 3-dimensional hearet volutme. the proposed new energy term of dynamic contour model considering the gray level and direction of controur vectors is effective to extract the closed heart boundary. And, we generatedvertical slice images from the extracted heart region images using the 2-dimensional linear interpolation by DT(distance transform). We showed that proposed algorithm is useful by 3-dimensional visualization of heart volume.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.185-186
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• 2008

In this paper, the nano-grating was measured by Scanning Probe Microscopy (SPM) system using digital Proportion, Integration and Derivative (PID) control. Through this measurement, we could confirm the improvement of the vertical resolution compared with analog Proportion and Integration (PI) control method.

• Journal of IKEEE
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• v.22 no.3
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• pp.858-861
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• 2018

In this paper, we propose the development of a small $360^{\circ}$ oral scanner lens module. The proposed small $360^{\circ}$ oral scanner lens module consists of a small $360^{\circ}$ high resolution(4MegaPixel) lens optical system, a 15mm image sensor unit, and a small $360^{\circ}$ mouth scanner lens external shape. A small $360^{\circ}$ high resolution lens optical system produces a total of nine lenses, the outer diameter of the lens not less than 15mm for use by children through the ages of adulthood. Light drawn by a small $360^{\circ}$ high resolution lens optical system is $90^{\circ}$ flexion so that image images are delivered to image sensors. The 15mm image sensor unit sends the converted value to the ISP(Image Signal Processor) of the embedded board after an image array through the column and the row address of the image sensor. The small $360^{\circ}$ mouth scanner lens outer shape was designed to fix the race to the developed lens. Results from authorized testing agencies to assess the performance of proposed small $360^{\circ}$ oral scanner lens modules, The optical resolving power of $360^{\circ}$ lens was more than 30% at 150 cycles/mm, $360^{\circ}$ lens angle was $360^{\circ}$ in vertical direction, $42^{\circ}{\sim}85^{\circ}$ in vertical direction, and lens distortion rate was 5% or less. It produced the same result as the world's highest level.