• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1759-1764
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• 2015

In this paper, we considered a design method of a circular polarization (CP) antenna for UHF (ultra high frequency) RFID (Radio Frequency IDentification) readers. The antenna is a dual-fed circular microstrip patch which produces right-handed CP. Quadrature hybrid coupler is used for dual feeding. The outputs of the coupler and circular patch are connected through copper wires, and the inductive reactance produced by the connecting wires is compensated by a ring-shaped slot inserted inside the circular patch. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in North American UHF RFID band (902-928 MHz), which includes domestic UHF RFID band. The antenna is fabricated, and the experiment results reveal a frequency band of 854-993 MHz for a voltage standing wave ratio < 2. The fabricated antenna is connected to a commercial RFID reader, and it showed a good performance of tag identification.

• Journal of Korea Water Resources Association
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• v.31 no.2
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• pp.123-132
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• 1998

Monitoring solute transport has been known to be difficult especially for the unsaturated soil. The object of this study is to investigate the TDR application to monitoring solute concentration in the vadose zone. The TDR calibration test was conducted for soil samples with various water contents and concentrations. The voltage attenuation of electromagnetic wave of TDR was used to estimate the bulk electrical conductivity of a soil. The relationship between the bulk soil electrical conductivity and the solute concentration was assumed to be linear at a constant volumetric soil water content. In this study four proposed relationships were compared using data obtained from KCI solution at three different concentrations. Relationships given by Topp, Daltaon, Yanuka showed the linearity between the bulk soil electrical conductivity and the solute concentration, which were more pronounced than Zegelin's. The three relationships were found to be useful to measure the solute concentration in the vadose zone. In addition, TDR method was proven to be a viable technique in monitoring solute transport through unsaturated soils in transient flow condition.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.10 no.2
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• pp.64-72
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• 1998

Dynamic response analysis is carried out for slender marine structures such as tensioned risers and tethers of tension leg platform, which are subjected to floating vessel motions as well as environmental forces arising from ocean waves. A mumerical analysis procedure is developed by using finite element model of the structural member. Dynamic analses are performed in the time domain for regular waves. Parameter studies are carried out to highlight the effects of surface vessel motions on the lateral dynamics of the structures. Example results of displacements, bending stresses are compared for various in water depth, environmental condition and vessel motion. Some instability conditions of the structures due to time-varying tension by vessel heave motion are discussed through the example analyses. As the results, the interaction between vessel surge and heave motions amplifies the total structural response of a riser. In the case of a tether, the effect of vessel heave motion during heavy storm is seemed to be quite significant to lateral response of the structure.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.249-255
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• 2015

In this paper, we present an azimuth error analysis for the correlative interferometer direction finding. The correlative interferometer is a direction finding method that compares the theoretical and measured phase differences. The direction of the radio transmitter can be estimated by obtaining the maximum correlation between two data sets. We used a 5-element circular array antennas arranged in a circle. To derive the correlation function between antenna elements, we assume that the incident plane wave arrives from a certain angle and the phase difference of each antenna can be derived by comparing with the reference. The suggested direction finding gives a relatively accurate result even if the radio transmitter is located in the higher altitude.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.89-95
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• 1997

X-cut y-propagation $LiNbO_{3}$ optical modulator is analyzed by finite element calculation. the purpose of this trial is the design of wide-bandwidth x-cut $LiNbO_{3}$ optical modulator with ridge wave guide, which was only applied to z-cut $LiNbO_{3}$ optical modulator. the simulation tool is examined by the comparison between our results and Becker's. And we consider the optimum position of optical waveguide to electrodes for decreasing the driving voltage. The calculated driving-voltage, characteristic impedance and microwave effective index at $1.3{\mu}{\textrm{m}}$ optical wavelength are 18 V.cm, $48.13{\Omega}$ and 2.168, respectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.23 no.1
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• pp.52-55
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• 2012

Background and Objectives : Based on histological findings, intracordal cysts are divided in two subtypes : retention cysts and epidermoid cysts. They are typically located in the superficial layer of the lamina propria and appeared as opaque ovoid buldging masses underlying the epithelium. They are characterized by unilateral diminished mucosal wave on stroboscopy. In this article, we report some cases of patients with an oval shaped-yellowish flat cyst. Materials and Method : At the clinic of the department of otorhinolaryngology in Gangnam Severance Hospital, with 3 female complained of hoarseness as subjects, using the stroboscopy we checked preoperative and postoperative vocal cord and operative findings. Surgery was performed under general anesthesia by the senior authors. All patients noted subjectively that their performing voice was improved. Results : During surgery, an oval shaped-yellowish flat cystic lesion was distinguished from normal epithelium. On palpation of this area with microforceps and cottons, the yellowish discharge was noted to move out from the opening of the cyst. In one case, the cyst was ruptured but remove the capsule completely. In other cases, sulcus was noted at the oppsite site. Conclusion : Because of the opening, the cyst was not easy to dissect and remove completely. After the debris was move out, fibrosis around the opening and invaginated epithelium extending into the deeper layers to the fold. The cyst was must removed carefully and completely for improvement of voice quality before evolving into a sulcus vocalis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.561-568
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• 2011

The purpose of this study is to measure displacements that occurs on a surface and interior of slope model and the shape when the slope is destroyed at vibration experiment of the slope model using close range photogrammetry. The circle targets and sphere targets are installed on a chamber and a slope model, while the earthquake wave are applied in regular time interval. The close range photogrammetric images are acquired in each displacements step until the slope model is destroyed. Those photos are processed by image processing method and the center points of targets are automatically extracted. Furthermore, the three-dimensional coordinates of targets are calculated by image orientation and bundle adjustment processing. As a result, amount of displacement at each level is precisely measured and provided the basic information for assessing the slope stability using three-dimensional measurement of the target movement and slope destruction.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.10
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• pp.1161-1174
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• 2011

An approach method of the semiotics theory is analyzing fashion: the look is that a sign represents one character and the image is interpreted as the destination of the changes. The fashion image interpretation by semiotics is possible because the fashion phenomenon by society has been accumulated in their abbreviation code. It is not possible to produce contradictions of the human imagination coined solution. The myth relieved to people, allowanced a meaning in the world and explained it have been unable to explain and protect us. Today's role of the world myth becomes the star's future. Public resting star's fashion image analysis promote that we understand the inherent desire. Madonna probably is one of the world's most famous women. To Create Madonna's own mythology staged image in various attire reveals symbolism. In this study, Madonna's fashion images, the myth 8 analysis of semiotics represent publicity. Madonna's album jacket 8 analysis of the myth. The fit and the relationship between the star and myths closely is obvious. The Madonna fashion image investigate that so forth implied myth into duality of feminine, upset of gender roles, upset of sexual roles, object of worship. In addition to the creation of these myths are based on sensuality heterosexual fashion images, body-conscious look, lingerie look, Androgynous Look, Dominatrix Look in the fashion style of the images, fashion items made to body suit, bra top, black panties, black boots, long gloves, pink, red, gold, satin, and leather; the addition, there are exaggerated props and accessories. These use such as the human body building wave blond hair. This study through Madonna's fashion image, semiotics analysis is acquainted with suitable means of myth.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.525-532
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• 1995

In this paper, a new try to measure nonlinear propagation characteristics of the pulse along blood vessel by using bispectral analysis is introduced, and the possibility of its application to the medical diagnosis is shown. In this method, the waveforms of pulse motion of blood vessel at two separated measuring points on the wall were detected from Doppler frequency modulation of transmitted probing ultrasonic waves. Then the auto- and crossbispectrum of detected waveforms are calculated to estimate the quadratic NTF (nonlinear transfer function) between the two measuring positions. In order to show relationships between the NTF and the nonlinear propagation characteristics, computer simulations have been performed. As the propagation distance increases, harmonic frequency components in NTF increases broadly due to the nonlinear effect in the propagation of blood pulse. In order to represent this phenomena quantitatively, we propose a new parameter, dispersion ratio of WTF. Basic experimental system was constructed by using 3.5MHz probing ultrasonic waves and the preliminary experiments were carried out on ague phantom and human body. Experimental results showed the validity of the measurement system enoughly.

• Journal of the Korean Geotechnical Society
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• v.34 no.7
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• pp.51-58
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• 2018

In this study a series of centrifuge tests were carried out in dry sand to analyze the comparison of lateral pile behavior for static loading and dynamic loading condition. In case of static loading condition, the lateral displacement was applied up to 50% of pile diameter by deflection control method. And the input sine wave of 0.1 g~0.4 g amplitude and 1 Hz frequency was applied at the base of the soil box using shaking table for dynamic loading condition. From comparison of experimental static p-y curve obtained from static loading tests with API p-y curves, API p-y curves can predict well within 20% error the ultimate subgrade reaction force of static loading condition. The ultimate subgrade reaction force of experimental dynamic p-y curve is 5 times larger than that of API p-y curves and experimental static p-y curves. Therefore, pseudo-static analysis applied to existing p-y curve for seismic design could greatly underestimate the soil resistance at non-linear domain and cause overly conservative design.