• Imaging Science in Dentistry
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• v.40 no.2
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• pp.63-68
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• 2010

Purpose : To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Materials and Methods : Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, $\rho$ ($g/cm^3$), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. Results : CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were $\rho$=0.001H+1.07 with $R^2$ value of 0.999 for Somatom Emotion, $\rho$=0.002H+1.09 with $R^2$ value of 0.991 for Alphard VEGA, $\rho$=0.001H+1.43 with $R^2$ value of 0.980 for i-CAT and $\rho$=0.001H+1.30 with $R^2$ value of 0.975 for Implagraphy. Conclusion: CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1601-1605
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• 2004

When codeword sequence has two or less successive transitions, the performance of 4th-order partial response maximum-likelihood (PRML) detector can be improved. However, the code leads to an unacceptable loss of performance due to the low code rate. For a rate 718 code that MTR constraint (i) of each codeword is limited to 2, and j is allowed to be 3 when codewords are connected, we modified the trellis of PRML detector to combine j=2 with J=3. We confirmed that the rate 718 coded 4th-order PRML detection with combined trellis achieves the SNR gain more than 2dB compared to the rate 819 coded 4u_order PRML detection at 10-s BER in high-density longitudinal or perpendicular magnetic recording systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.75-81
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• 2011

Protein molecules are combined with another ones which have similar shapes at pocket positions. The pocket positions can be good references to describe the shapes of protein molecules. Harris corner detector is commonly used to detect feature points of 2 or 3D objects. Feature points can be found on the pocket areas and the points which have high derivatives. Generally speaking, the densities of feature points are relatively high at pocket areas because the shapes of pockets are concave. The pocket areas can be decided by the subdivision of voxel cubes which include feature points. The Euclidean distances between feature points and the central coordinate of the decided pocket area are calculated and sorted. The graph of sorted distances describes the shape of a protein molecule and the distribution of feature points. Therefore, it can be used to classify protein molecules by their shapes. Even though the shapes of protein molecules have been distorted with noises, they can be recognized with the accuracy more than 95 %. The accurate shape recognition provides the information to predict the binding properties of protein molecules.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.337-343
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• 2010

1-Deoxynojirimycin(1-DNJ) was hardly detected by general UV detector. Therefore, in this study, we analyzed 1-DNJ, a effective functional material in which was contained the leaves of Cudrania tricuspidata and its tea by gas-chromatography. Synthesized a TMS derivative by attaching trimethylsilyl group to 1-DNJ, analyzed this by GC, and could detect a good peak. The leaves of Cudrania tricuspidata contains $1154.83{\pm}56.67$ ug/g.d.w of 1-DNJ and tea of Cudrania tricuspidata leaves does $8.01{\pm}0.61$ ug/g.d.w. This means the contents of 1-DNJ was nearly identical to each other. The larger size of the leaves had the more contents of 1-DNJ and the middle region of collection was the highest than any other collective regions of leaves.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1275-1280
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• 2018

We demonstrated transmission direct phase-measuring deflectometry (DPMD) with a specular phase object having discontinuous surfaces by using two displays and a two-dimensional array detector for display and by recording the distorted fringe patterns. Three-dimensional (3D) information was obtained by calculating the height map directly from the phase information. We developed a mathematical model of the phase-height relationship in transmission DPMD. Unlike normal transmission deflectometry, this method supports height measurement directly from the phase. Compared with other 3D measurement techniques such as interferometry, this method has the advantages of being inexpensive and easy to implement.

• Particle and aerosol research
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• v.13 no.1
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• pp.25-31
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• 2017

This paper offer the characteristics for the detection and classification of biological and non-biological aerosol particles in the air by using laser-induced-fluorescence (LIF) based Bio-aerosol Detection System (BDS). The BDS is mainly consist of an optical chamber, in-outlet nozzle system, 405 nm diode laser, an avalanche photo detector (APD) for scattering signal and photomultiplier tubes (PMT) for fluorescence signals in two different wavelength range ; F1, 510-600 nm and F2, 435-470 nm. The detection characteristics, especially ratio of fluorescence signal intensity were examined using well-known components : polystylene latex (PSL), fluorescence PSL, $2{\mu}m$ of SiO2 micro sphere, dried yeast, NADH, ovalbumin, fungicide powder and standard dust. The results indicated that the 405 nm diode laser-based LIF instrument can be a useful bio-aerosol detection system for unexpected biological threaten alter in real-time to apply for dual-use technology in military and civilian fields.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.48-52
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• 2008

According to extremely industrial growth, gas facilities, equipments and chemical plants are gradually increased due to incremental demands of annual amount of gases. The safety management of gases, however, is still far from their requirements. Methane, the principal ingredient of natural gas, is inflammable and explosive and is much used in factories and houses. Therefore, these gas safety management is essential. So, we, with a program of the gas safety management, hope to develop the detection system of methane gas leak using mid-infrared ray LED and PD with $3.2\;{\mu}m$. The cryogenic cooling device is indispensible at laser but needless at LED driven on the room temperature if manufacturing optical sensor with $3.2\;{\mu}m$. It, consequently, is not only possible to implement for subminiature and portable type but also able to speedily detect methane of extremely small quantities because the $CH_4$ absorption intensity at $3.2\;{\mu}m$ is stronger than that at $1.67\;{\mu}m$. Our objective of research is to prevent gas leak accidents from occurring previously and to minimize the extent of damage from them.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.4
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• pp.237-243
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• 1995

We have studied methods of detecting attenuation of solid materials such as silicon wafer and piezoelectric $LiTaO_3$ by means of optical probing techniques. We have performed measurements of surface acoustic waves(SAW) generated from 90 degree wedge type transducer and also from inter-digital transducers(IDT). SAW of 20.0 MHz was generated on a silicon wafer from the 90 degree wedge type transducer and those of 20.8 and 14.5 MHz are generated on a $LiTaO_3$ from the IDT. Then any surface-corrugation resulted from the above SAW was investigated by He-Ne laser beams. We projected laser beams, which were modulated by an optical chopper, on the SAW of the same frequency and then measured the scattered beam by the lock-in amplifier. We modulated and synchronized both SAW and the incident laser beam as well as the phase sensitive detector(PSD) to the same frequency in order to simplify our measurement system. We obtained the attenuation coefficients of SAW to be $0.62{\sim}0.75dB/mm$(from IDT1, 20.8 MHz), and $0.60{\sim}0.72dB/mm$(from IDT2, 14.5 MHz), $0.83{\sim}1.28dB/mm$(from the wedge type), respectively.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.144-152
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• 2007

We propose a 3D modeling method for surface inspection of non-linear moving object. The laser lines reflect the surface curvature. We can acquire 3D surface information by analyzing projected laser lines on object. ill this paper, we use multi-line laser to make use of robust of single stripe method and high speed of single frame. Binarization and channel edge extraction method were used for robust laser line extraction. A new labeling method was used for laser line labeling. We acquired sink information between each 3D reconstructed frame by feature point matching, and registered each frame to one whole image. We verified the superiority of proposed method by applying it to container damage inspection system.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.35-42
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• 1989

The mode of transglycosylation reaction observed during the action of low-molecular-weigh $\beta$-D-glucosidase ($\beta$-D-glucoside glucohydrolase, EC3.2.1.21) purified from Trichoderma koningii ATCC 26113 was investigated using $^{1}H$-NMR spectroscopy. The enzyme was purified by the series of procedures including ammonium sulfate precipitation, and fractionations by column chromatographies on Bio-Gel P-150, DEAE-Sephadex A-50, and SP-Sephadex C-50. The final purification was performed by the band eluation after preparative polyacrylamide gel electrophoresis. The enzyme showed its molecular size of 78,000 through the analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its isoelectric point of 5.80 through the analysis of analytical isoelectric focusing. The H-1 proton resonances were analyzed. After the reaction of the enzyme with cellobiose, the reaction products were separated by high performance liquid chromatography using refractive index detector. H-1 resonances of the products were consisted with those of gentiobiose [$\beta$-D-glucopyranosyl--(1,6)-D-glucopyranose], and cellotriose [$\beta$-D glucopyranosyl-(1,4)-$\beta$-D-glucopyranosyl]-(1,4)-D-glucopyranose] with minor resonances of sophorose [$\beta$-D-glucopyranosyl-(1,2)-D-glucopyranose], respectively.