• Korean Journal of Remote Sensing
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• v.18 no.3
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• pp.141-146
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• 2002

Chlorophyll-a concentration maps of Yongdam reservoir in September and October, 2001 were produced using Landsat ETM imagery and the in-situ water quality measurement data. In-situ water samples were collected on 16th September and 18th October during the satellite overpass. The correlations between the DN values of the imagery and the values of chlorophyll-a concentration were analyzed. The visible bands(band 1, 2, 3) and the near infrared band(band 4) data of September image showed the correlation coefficient values higher than 0.9. The October image showed correlation coefficient values of about 0.7 due to the low variations of chlorophyll-a concentration. Regression models between the DN values of the Landsat ETM image and the chlorophyll-a concentration have been developed for each image. The developed regression models were then applied to each image, and finally the chlorophyll-a distribution maps of Yongdam reservoir were produced. The produced maps showed the spatial distribution of the chlorophyll-a in Yongdam reservoir in a synoptic way so that the tropic state could be easily monitored and analysed in the spatial domain.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.5
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• pp.426-431
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• 2007

When a high-energy ultrasound propagates through a solid body that contains a crack or a delamination, the two faces of the defect do not ordinarily vibrate in unison, and dissipative phenomena such as friction, rubbing and clapping between the faces will convert some of the vibrational energy to heat. By combining this heating effect with infrared imaging, one can detect a subsurface defect in material in real time. In this paper a realtime detection of the brazing defect of thin Inconel plates using the UIR (ultrasonic infrared imaging) technology is described. A low frequency (23 kHz) ultrasonic transducer was used to infuse the welded Inconel plates with a short pulse of sound for 280 ms. The ultrasonic source has a maximum power of 2 kW. The surface temperature of the area under inspection is imaged by an infrared camera that is coupled to a fast frame grabber in a computer. The hot spots, which are a small area around the bound between the two faces of the Inconel plates near the defective brazing point and heated up highly, are observed. And the weak thermal signal is observed at the defect position of brazed plate also. Using the image processing technology such as background subtraction average and image enhancement using histogram equalization, the position of defective brazing regions in the thin Inconel plates can be located certainly.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2529-2532
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• 2003

The quality of agricultural products is represented a degree of freshness and a special qualify that has a close relation to commercial value. To grade tomatoes, it used to nondestructive equipment of a charge-coupled device(CCD) camera and near-infrared(NIR) spectrum analysis method. The NIR spectrum analysis method is used to determine internal qualities such as a brix and an acidity. The CCD camera is used to measure external qualities like color and a size of tomatoes. This paper explaines the structure and movement of the automatic grade system and applies the algorithm for deformed tomtatoes and characteristics of tomatoes through image processing to the grade system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.140-146
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• 2012

A variety of dyes are commercially available today, there is an ongoing need for new chromophoric systems and low-band-gap materials. For example, near-infrared (NIR) emission has received increased attention for applications in bioassays and medicine while NIR absorption is demanded for laser-welding of plastics or efficient blocking of heat rays. Most of the commercially available NIR materials are not suitable for such purposes owing to their insufficient stability. We have developed a novel NIR-absorbing polyaromatic dye. By extending the system of perylenebis(dicarboximide)s along the molecular long axis, we have obtained the higher homologue pentarylenebis(dicarboximide). We have tried to introduce imide functional group to pentarylene in order to increase chemical and thermal stability.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.479-481
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• 2003

Large number of coral reefs in Thailand waters make the use of satellite imagery probably the only practical method for their monitoring. This paper reports the result of detecting small shallow-water coral reef by using maximum likelihood classification technique. Combination of blue/green and near-infrared band ratio are used as spectral signatures derived from a Landsat 7 imagery covering western portion of the Gulf of Thailand. Result assessment reveals accuracy significantly over 60 percent. The result is encouraging and would be a basis for further study to realize the full potential and limitation of this technique.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.35.2-35.2
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• 2020

Submillimeter galaxies (SMGs) have played an important role in the understanding of galaxy evolution and cosmic star formation history at high redshift because they are known as being located at z ~ 2 and harbor a vigorous star formation. Therefore studying properties of SMGs can lead us to understand evolution of massive and actively star forming galaxies and distribution of cosmic star formation density. Recently we detected 548 SMGs near North Ecliptic Pole with JCMT/SCUBA-2 from the JCMT large program covering about 2 deg2 so far. To derive their physical parameters, we compiled a multi-wavelength photometry ranging from optical (0.3 ㎛) to submillimeter (850 ㎛) by cross-identifying counterparts at different wavelengths. In order to find counterparts, we used either VLA-1.4 GHz image and/or Spitzer/IRAC 3.6 ㎛, 4.5 ㎛ image. The number of SMGs with relatively robust counterparts is 349. In this talk, we present photometric redshifts, stellar mass, star formation rates, total infrared luminosity, and AGN fraction of these 349 SMGs derived through SED fitting analysis.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.82.1-82.1
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• 2012

GRB100205A is a Gamma Ray Burst (GRB) which is suspected to be at redshift z=11-13 due to its very red H-K color($(H-K)_{vega}=2.1{\pm}0.5$). We observed a field centered at GRB100205A with Wide Field Camera (WFCAM) at United Kingdom Infrared Telescope (UKIRT) in Hawaii, in order to search a quasar that could be located around the GRB. The images were obtained in J, H, and K filters covering a square area of $0.78deg^2$. Our J-, H-, and K-band data reach the depths of 22.5, 22.1, and 21.0 mag (Vega) at $5{\sigma}$, respectively. Also using z-band image observed by CFHT, we find 8 candidates that have colors consistent with a quasar at z=11-13(non-detection in z-, J-band and $(H-K)_{vega}$ > 1.6). However, the shallow depths of J-, H-band are not enough to verify their true nature. Instead, we identify many red objects to be old or dusty galaxies at $z{\geq}3$. The number density of such objects appears about twice or more than that of the field of Cosmological Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) of UKIRT Infrared deep sky survey (UKIDSS). On scales between 0.18' and 15' the correlation function is well described by a power law with an exponent of ${\approx}-0.9$ and this implies that those objects are like galaxies. It is interesting that many red galaxies exist in the region where the GRB was detected.

• Korean Journal of Remote Sensing
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• v.20 no.5
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• pp.337-351
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• 2004

Our laboratory originally developed the compact, multi-spectral, automatic aerial photographic system PKNU3 to allow greater flexibility in geological and environmental data collection. We are currently developing the PKNU3 system, which consists of a color-infrared spectral camera capable of simultaneous photography in the visible and near-infrared bands; a thermal infrared camera; two computers, each with an 80-gigabyte memory capacity for storing images; an MPEG board that can compress and transfer data to the computers in real-time; and the capability of using a helicopter platform. Before actual aerial photographic testing of the PKNU3, we experimented with each sensor. We analyzed the lens distortion, the sensitivity of the CCD in each band, and the thermal response of the thermal infrared sensor before the aerial photographing. As of September 2004, the PKNU3 development schedule has reached the second phase of testing. As the result of two aerial photographic tests, R, G, B and IR images were taken simultaneously; and images with an overlap rate of 70% using the automatic 1-s interval data recording time could be obtained by PKNU3. Further study is warranted to enhance the system with the addition of gyroscopic and IMU units. We evaluated the PKNU 3 system as a method of environmental remote sensing by comparing each chlorophyll image derived from PKNU 3 photographs. This appraisement was backed up with existing study that resulted in a modest improvement in the linear fit between the measures of chlorophyll and the RVI, NDVI and SAVI images stem from photographs taken by Duncantech MS 3100 which has same spectral configuration with MS 4000 used in PKNU3 system.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1125-1137
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• 2011

Recently, there have been previous research about the iris recognition in mobile device to increase portability, whose accuracy is affected by the quality of iris image. Iris image is affected by illumination environment during the image acquisition. The existing system has high accuracy in indoor environment. However the accuracy is degraded in outdoor environment, because the gray levels of iris patterns in image are changed, and ghost and eyelash shading regions are produced by the sunlight of various wavelengths into iris region. To overcome these problems, we propose new mobile iris camera system which uses the near-infrared (NIR) light illuminator of 850 nm and band pass filter (BPF) of 850 nm. To measure the performance of the proposed system, we compared it to the existing one with the iris images captured in indoor and outdoor sunlight environments in terms of the equal error rates (EER) based on false acceptance rate (FAR) and false rejection rate (FRR). The experimental result showed that the proposed system had the lower EERs than those of previous system by 0.96% (with frontal light in indoors), 4.94% (with frontal light in outdoor), 9.24% (with side light in outdoor), and 7% (with back light in outdoor), respectively.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.127-133
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• 2011

Arteria radialis is a branch of the brachial artery extending down the forearm around the wrist where it closes to skin surface. In the oriental medicine, the skin above arteria radialis has an important role because oriental medicine practitioners put their finger tips on the area, and diagnose patient's health conditions by feeling the pulsation of the arterial contraction. The finger tip diagnostic method relies on subjective decision of the practitioner; and there is a need to develop an objective diagnostic modality. The pulsation of the arterial contraction appears not only a movement on the site but also as temperature fluctuation due to pulsatile feeding of warmer blood. The goal of this study is to demonstrate a feasibility of using an infrared camera quantitatively to detect the temperature fluctuation on the skin. Clinical important three different areas, called chon, gwan, chuk, near a wrist where the arteria radialis reaches close to skin surface are marked with small pieces of surgical tape. A high-speed and high-resolution infrared camera with a 3 cm of field of view measures these areas for 10 second at 200 frames per second with a 320*240 pixel size. The pulsatile temperature fluctuation is calculated after passing a band pass filter to remove any stationary temperature over 10 second. The temperature fluctuation of a healthy male volunteer is measured at a room temperature as a control, and is compared with another measurement performed after 20 minutes staying in a room at a 40 degree Celsius. This comparison is repeated for three times, and indicates that the fluctuation increases after staying 20 minutes in the warm room. This increase becomes smaller when the person stays in the warm room with an acupuncture treatment that decreases body temperature. So that an objective diagnostics on the site may become feasible.