• Composites Research
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• v.35 no.3
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• pp.201-215
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• 2022

This paper presents the development of thin and lightweight ultra-high temperature radar-absorbing ceramic composites composed of an aluminosilicate ceramic matrix-based geopolymer reinforced ceramic fiber and sendust magnetic nanoparticles in X-band frequency range (8.2~12.4 GHz). The dielectric properties with regard to complex permittivity of ceramic/sendust-aluminosilicate composites were proportional to the size of sendust magnetic nanoparticle with high magnetic characteristic properties as flake shape and its concentrations in the target frequency range. The characteristic microstructures, element composition, phase identification, and thermal stability were examined by SEM, EDS, VSM and TGA, respectively. The fabricated total thicknesses of the proposed single slab ultra-high temperature radar absorber correspond to 1.585 mm, respectively, exhibiting their excellent EM absorption performance. The behavior of ultra-high temperature EM wave absorption properties was verified to the developed free-space measurement system linked with high temperature furnace for X-band from 25℃ to 1,000℃.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.701-709
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• 2022

The purpose of this study was to compare the differences according to the visual selection and rotation order during sequential rotational jump for female dancers of a Korean ballet company by classifying them into take-off and landing sections. 10 subjects (age: 26.0±2.9 yrs, height: 163.4±3.3 cm, weight: 46.8±3.6 kg, ballet career: 12.3±5.9 yrs) participated in the study. Using a 3D motion analyzer and a force platform, the height of the body center and the ground reaction force during take-off and landing were measured. According to the visual condition (using both eyes, using left eye, using right eye) and rotation order (first rotation, second rotation), it was analyzed through repeated measurement two-way analysis. Height of the CM was higher in the first jump. In take-off, Fx was lateral force of left foot and medial force of right foot were strong in second rotation, and Fy was forward force was strong in first rotation of right foot. Fz was no significant. In landing, Fy showed backward force was strong when landing the second time from the left foot, and the backward force was strong when using the left sight from the right foot. Fz was strong on the second landing on the left foot and the first landing on the right foot.

• The Journal of the Acoustical Society of Korea
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• v.26 no.2
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• pp.61-68
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• 2007

The frequency response of a microphone, which indicates the frequency range that a microphone can output within the approved level, is one of the most significant standards used to measure the characteristics of a microphone. At present, conventional methods of measuring the frequency response are complicated and involve the use of expensive equipment. To complement the disadvantages, this paper suggests a new algorithm that can measure the frequency response of a microphone in a simple manner. The algorithm suggested in this paper generates the Optimized Aoshima's Time Stretched Pulse(OATSP) signal from a computer via a standard speaker and measures the impulse response of a microphone by convolution the inverse OATSP signal and the received by the microphone to be measured. Then, the frequency response of the microphone to be measured is calculated using the signals. The performance test for the algorithm suggested in the study was conducted through a comparative analysis of the frequency response data and the measures of frequency response of the microphone measured by the algorithm. It proved that the algorithm is suitable for measuring the frequency response of a microphone, and that despite a few errors they are all within the error tolerance.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.194-194
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• 2017

Camelina (Camelina sativa L.) is a potential bio-energy crop that has short life cycle about 90 days and contains high amount of unsaturated fatty acid which is adequate to bio-diesel production. Enhancing environmental stress tolerance is a main issue to increase not only crop productivity but also big mass production. CsRCI2s (Rare Cold Inducible 2) are cold and salt stress related protein that localized at plasma membrane (PM) and assume to be membrane potential regulation factor. These proteins can be divide into C-terminal tail (CsRCI2D/E/F/G) or no-tail group (CsRCI2A/B/C/H). However, function of CsRCI2s are less understood. In this study, physiological responses and functional characterization of CsRCI2s of Camelina under salt stress were analyzed. Full-length CsRCI2s (A/B/E/F) and CsPIP2;1 sequences were confirmed from Camelina genome browser. Physiological investigations were carried out using one- or four-week-old Camelina under NaCl stress with dose and time dependent manner. Transcriptional changes of CsRCI2A/B/E/F and CsPIP2;1 were determined using qRT-PCR in one-week-old Camelina seedlings treated with NaCl. Translational changes of CsRCI2E and CsPIP2;1 were confirmed with western-blot using the antibodies. Water transport activity and membrane potential measurement were observed by cRNA injected Xenopus laevis oocyte. As results, root growth rate and physiological parameters such as stomatal conductance, chlorophyll fluorescence, and electrolyte leakage showed significant inhibition in 100 and 150 mM NaCl. Transcriptional level of CsPIP2;1 did not changed but CsRCI2s were significantly increased by NaCl concentration, however, no-tail type CsRCI2A and CsRCI2B increased earlier than tail type CsRCI2E and CsRCI2F. Translational changes of CsPIP2;1 was constitutively maintained under NaCl stress. But, accumulation of CsRCI2E significantly increased by NaCl stress. CsPIP2;1 and CsRCI2A/B/E/F co-expressed Xenopus laevis oocyte showed decreased water transport activity as 61.84, 60.30, 62.91 and 76.51 % at CsRCI2A, CsRCI2B, CsRCI2E and CsRCI2F co-expression when compare with single expression of CsPIP2;1, respectively. Moreover, oocyte membrane potential was significantly hyperpolarized by co-expression of CsRCI2s. However, higher hyperpolarized level was observed in tail-type CsRCI2E and CsRCI2F than others, especially, CsRCI2E showed highest level. It means transport of $Na^+$ ion into cell is negatively regulated by expression of CsRCI2s, and, function of C-terminal tail is might be related with $Na^+$ ion influx. In conclusion, accumulation of NaCl-induced CsRCI2 proteins are related with $Na^+$ ion exclusion and prevent water loss by CsPIP2;1 under NaCl stress.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.17-23
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• 2020

Biometric information indicating measurement items related to human characteristics has attracted great attention as security technology with high reliability since there is no fear of theft or loss. Among these biometric information, fingerprints are mainly used in fields such as identity verification and identification. If there is a problem such as a wound, wrinkle, or moisture that is difficult to authenticate to the fingerprint image when identifying the identity, the fingerprint expert can identify the problem with the fingerprint directly through the preprocessing step, and apply the image processing algorithm appropriate to the problem. Solve the problem. In this case, by implementing artificial intelligence software that distinguishes fingerprint images with cuts and wrinkles on the fingerprint, it is easy to check whether there are cuts or wrinkles, and by selecting an appropriate algorithm, the fingerprint image can be easily improved. In this study, we developed a total of 17,080 fingerprint databases by acquiring all finger prints of 1,010 students from the Royal University of Cambodia, 600 Sokoto open data sets, and 98 Korean students. In order to determine if there are any injuries or wrinkles in the built database, criteria were established, and the data were validated by experts. The training and test datasets consisted of Cambodian data and Sokoto data, and the ratio was set to 8: 2. The data of 98 Korean students were set up as a validation data set. Using the constructed data set, five CNN-based architectures such as Classic CNN, AlexNet, VGG-16, Resnet50, and Yolo v3 were implemented. A study was conducted to find the model that performed best on the readings. Among the five architectures, ResNet50 showed the best performance with 81.51%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.237-245
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• 2017

This cross-sectional descriptive study was conducted to determine the health conditions and health behaviors of merchants at traditional markets and compare them with members of the general population[ED highlight - do you mean "members of the general population"?]. The data were collected from 307 merchants at N traditional market in C City from 1-20 June 2015 at D Health Center of C City after physical measurement and blood collection and then analyzed using SPSS WIN 21.0. The male, female, and overall smoking rates of merchants at the traditional market were 34.2%, 3.5% and 11.1%, the annual drinking rates were 68.4%, 38.5%, and 45.9%, and the rates of subjects under stress and the rates of experiencing depression were 23.7%, 28.5%, and 27.4% and 5.3%, 6.1%, and 5.9%, respectively, which were all relatively lower than members of the general population[ED highlight - please ensure that my changes here are in keeping with your intended meaning.]. The male, female and overall rates of medium-level physical activities and walking were 32.9%, 19.9%, and 23.1% and 85.5%, 79.2%, and 80.8%, respectively, to have relatively good health behaviors, and the mental health is relatively fine than members of the general population[ED highlight - please clarify this, I cannot infer your intended meaning.]. However, test group[ED highlight - the test group? Please specify.] had high prevalence rates of hypertension, diabetes, hypercholesterolemia, and metabolic syndrome. Moreover, as the duration of work increased, the abdominal circumference as well as the prevalence rates of low HDL-cholesterol, hypertension, metabolic syndrome, and arthritis increased. Therefore, the specific causes of these shall be determined, and the long-term daily life improvement program shall be prepared and applied continuously for merchants at traditional markets.[ED highlight - please specify what these refer to; however, the entire sentence can probably be deleted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.859-867
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• 1997

In order to utilize the processing wastes of squid, chitosans were manufactured from the pens of domestic squid, Todarbdes pacificus and foreign squid, Ommastrephes bartrami and then, its rheological properties were studied. The amounts of nitrogen and minerals of the domestic squid pens were $11.4\%\;and\;0.1\%$ respectively, whereas those of its chitosan were $7.5\%\;and\;0.2\%$. In case of foreign squid pen and chitosan, the amounts of nitrogen and minerals were $12.1\%,\;0.8\%\;and\;7.8\%,\;0.2\%$ respectively. Intrinsic viscosity $([\eta]) $ of domestic and foreign squid pen chitosans were decreased with increasing pH from 3.4 to 5.4 which might be due to the reduced repulsion in inter- of intra- chitosan molecules. Intrinsic viscosity of the domestic and foreign squid pen chitosans were decreased with increasing NaCl concentration thus indicated that the domestic and foreign squid pen chitosans were polyelectrolyte molecules and stiffness of squid pen thitosans were 0.11 similar to that of k-carrageenan. Flow type of squid pen chitosan solutions were pseudoplastic fluids without yield stress by the viscosity measurement. But the squid pen chitosan solutions showed newtonian fluid up to $0.15\~0.24\%$ concentration for domestic and $0.21\~0.24\%$ concentration for foreign at $10\~50\%$. Concentration dependence of consistency index in infinitive dilute domain (Kc) were higher in the dilute domain than entangled domain. Activation energies (Ea) of the squid pen chitosans were 3.7, 6.3, 3.6, 4.0 and 4.1 Kcal/g moi for domestic and 3.2, 3.1, 3.4, 3.8 and 3.6 Kcal/g mol for foreign at 0.1, 0.15, 0.25, 0.35 and $0.5\%$, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.5-9
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• 2004

In this paper, we studied the OCT(Optical Coherence Tomography) system which it has been extensively studied because of having some advantages such as high resolution cross-sectional images, low cost, and small size configuration. A basic principle of OCT system is Michelson interferometer. The characteristics of light source determine the resolution and the transmission depth. As a results, the light source have a commercial SLD with a central wavelength of 1,285 nm and FWHM(Full Width at Half Maximum) of 35.3 nm. The optical delay line part is necessary to equal of the optical path length with scattered light or reflected light from sample. In order to equal the optical path length, the stage which is attached to reference mirror is moved linearly by step motor And the interferometer is configured with the Michelson interferometer using single mod fiber, the scanner can be focused of the sample by using the reference arm. Also, the 2-dimensional cross-sectional images were measured with scanning the transverse direction of the sample by using step motor. After detecting the internal signal of lateral direction at a paint of sample, scanner is moved to obtain the cross-sectional image of 2-demensional by using step motor. Photodiode has been used which has high detection sensitivity, excellent noise characteristic, and dynamic range from 800 nm to 1,700 nm. It is detected mixed small signal between noise and interference signal with high frequency After filtering and amplifying this signal, only envelope curve of interference signal is detected. And then, cross-sectional image is shown through converting this signal into digitalized signal using A／D converter. The resolution of the OCT system is about 30$\mu\textrm{m}$ which corresponds to the theoretical resolution. Also, the cross-sectional image of ping-pong ball is measured. The OCT system is configured with Michelson interferometer which has a low contrast because of reducing the power of feedback interference light. Such a problem is overcomed by using the improved inteferometer. Also, in order to obtain the cross-sectional image within a short time, it is necessary to reduce the measurement time for improving the optical delay line.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.64-68
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• 2004

Purpose : To study the feasibility of verifying real-time 2-D dose distribution measurement system with the scintillation screen for the quality assurance. Materials and Methods : The water phantom consisted of a scintillation screen (LANEX fast screen, Kodak, USA) that was axially located in the middle of an acrylic cylinder with a diameter of 25 cm. The charge-coupled device (CCD) camera was attached to the phantom In order to capture the visible light from the scintillation screen. To observe the dose distribution In real time, the intensity of the light from the scintillator was converted to a dosage. The isodose contours of the calculations from RTP and those of the measurements using the scintillation screen were compared for the arc therapy and the Intensity modulated radiation therapy (IMRT). Results : The kernel, expressed as a multiplication of two error functions, was obtained in order to correct the sensitivity of the CCD of the camera and the scintillation screen. When comparing the calculated isodose and measured isodose, a discrepancy of less than 8 mm in the high dose region was observed. Conclusion : Using the 2-D dosimetry system, the relationship between the light and the dosage could be found, and real-time verification of the dose distribution was feasible.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.275-289
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• 2002

The objective of this study was to develop an in vitro assessment of sperm fertilizing capacity of bulls and investigate the factors influencing sperm function and characteristics of frozen-thawed bovine spermatozoa. in vitro fertilization (IVF), the evaluation of motility and normal morphology, HOST (hypoosmotic swelling test), Ca-ionophore induced acrosome reaction, luminol and lucigenin-dependent chemiluminescence for the measurement of reactive oxygen species (ROS), the measurement of malondialdehyde formation for the analysis of lipid peroxidation (LPO), and the evaluation of DNA fragmentation using the method of 747-mediated nick end labelling (TUNEL) by flow cytometry were performed in frozen-thawed bovine spermatozoa. Correlations between the rates of fertilization, blastocyst formation after IVF and the values of respective assays were investigated. 1. IVF rate and blastocyst formation rate averaged 64.4% and 34.3% for spermatozoa from high -fertility bull group and averaged 18.5% and 6.2% for spermatozoa from low-fertility bull group, respectively. There were significantly different between two bull groups. Sperm motility and percentage acrosome reaction averaged 79.0% and 66.2% for spermatozoa from high-fertility bull group and averaged 40.7% and 22.9% for spermatozoa from low-fertility bull group, respectivitely. There were not different between two bull groups. 2. Luminol depenent chemiluminescence, LPO and DNA fragementation averaged 6.4, 2.0 nmol and 2.6% from spermatozoa from high-fertility bull group and averaged 6.5, 3.1 nmol and 7.4% for spermatozoa from low-fertility bull group, respectively. There were significantly different between two bull groups. There was no significant difference in lucigenin dependent chemiluminescence between two bull groups. 3. Fertilization rate was positively correlated with motility and the rate of Ca-ionophore induced acrosome reaction, but negatively correlated with the frequency of luminol-dependent chemiluminescence, the rate of LPO, and the percentage of sperm with DNA fragmentation. There was no correlation between fertilization rate and the percentage of swollen spermatozoa, normal morphology, and the frequency of lucigenin-dependent chemiluminescence. 4. Blastocyst formation rate was positively correlated with the rate of Ca-ionophore induced acrosome reaction, but negatively correlated with the frequency of luminol-dependent chemiluminescence, the rate of LPO, and the percentage of sperm with DNA fragmentation. There was no correlation between blastocyst formation rate and motility, the percentage of swollen spermatozoa, normal morphology, and the frequency of lucigenin-dependent chemiluminescence. In conclusion, these data suggest that ROS significantly impact semen quality. The assays of this study may provide a basis fur improving in vitro assessment of sperm fertilizing capacity.