• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.18-22
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• 2012

This study was performed to evaluate the sensitivity of conventional film-screen radiography (CFSR) and direct digital radiography (DDR) for detection of various amounts of free peritoneal fluid. Ten adult male healthy beagles were used in this study. Radiographic examinations were performed in the right lateral and ventrodorsal positions. Fluid was injected in increments of 2.0 ml/kg of body weight up to 20.0 ml/kg of body weight. The images of CFSR and DDR were evaluated by two veterinary radiologists for evidence of abdominal fluid without knowledge of injected fluid volume. Data were evaluated by using the receiver operation curve (ROC) analysis and the area under the curve (AUC). There was no significant difference in detection of peritoneal fluid between DDR and CFSR in the ROC analysis. The accuracy of CFSR (0.805) was relatively higher than that of DDR (0.733), based on the ROC analysis and AUC. AUC of CFSR was higher in most injection doses. These results suggest that CFSR is more accurate than DDR for the detecting peritoneal fluid. Therefore, for situation in which digital radiographs are equivocal or small amount of fluid is suspected, other imaging modalities, such as ultrasonography would be helpful for determining the presence of fluids.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.835-841
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• 2013

Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.457-463
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• 2012

The basilar membrane (BM), one of organs of cochlea, has the specific positions of the maximum amplitude at each of related frequencies. This phenomenon is due to the geometry of BM. In this study, as the part of the research for the development of fully implantable artificial cochlea which is based on polymer membrane, parametric studies are performed to suggest the desirable artificial basilar membrane model which can detect wider range of frequency separation. The vibro-acoustic characteristics of the artificial basilar membrane are predicted through finite element analysis using commercial software Abaqus. Simulation results are verified by comparing with experimental results. Various geometric shapes of the BM and residual stress effects on the BM are investigated through the parametric study to enable a wider detectable frequency separation range.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.497-503
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• 2014

Minimally invasive intramedullary nail insertion or plate osteosynthesis has shown good results for the treatment of long bone fractures. However, directly seeing the fracture site is impossible; surgeons can only confirm bone fragments through a fluoroscopic imaging system. The narrow field of view of the equipment causes malalignment of the fracture reduction, and radiation exposure to medical staff is inevitable. This paper suggests two methods to solve these problems: surgical navigation using 3D models reconstructed from computed tomography (CT) images to show the real positions of bone fragments and estimating the rotational angle of proximal bone fragments from 2D fluoroscopic images. The suggested methods were implemented using open-source code or software and evaluated using a model bone. The registration error was about 2 mm with surgical navigation, and the rotation estimation software could discern differences of $2.5^{\circ}$ within a range of $15^{\circ}$ through a comparison with the image of a normal bone.

• Journal of KSNVE
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• v.6 no.1
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• pp.107-114
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• 1996

The damping characteristics of a cylindrical structure containing oil and bearing balls is investigated for external bending forces. The experimental data obtained through the use of bearing balls with viscous oil in a column is given and analyzed. The viscous action of the oil and inertia effects of the balls on the inside of column create a drag force. The drag force dampens the vibration of the column. This study aims to search for an optimum combination of oil and balls which would produce maximum damping. Machining oils of various viscosities along with ball bearings of various sizes place inside cantilevered aluminium tubes of various diameters to create a rig on which the damping properties of the oil and balls can be studied. The contileved tubes are studied in both horizontal and vertical positions in order to gauge the effect of gravity on the system. The actions of the ball in the column and damping characteristics are investigated according to the dimensionless terms. The Buckingham theorem is used to reduce the variables and to predict the damping of an oil ball column. Though the damping ratio remains fairly constant in the horizontal position of column, the damping ratio begins to increase as the ratio of the number of balls and column length rise above 0.28 in the vertical position of oil ball column. The ratio of the ball diameter to column diameter influences the damping ratio with an optimum diameter ratio. Slenderness ratio and gravity effects on the damping ratio ane investigated.

• Journal of Life Science
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• v.25 no.1
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• pp.37-43
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• 2015

We have investigated the effects of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), indole-3-acetic acid (IAA) and methyl jasmonate (MeJA) on the development of aerenchyma in the primary root of maize (Zea mays). Because plant hormones affected the longitudinal organization of the primary root, we need an indicator to direct the positions for comparison between control and hormone-treated roots. Therefore, the zones of the maize primary root were categorized as PR25, PR50 and PR75, where each value indicates the relative position between the root tip (PR0) and the base (PR100). Aerenchyma was not observed at PR25 and PR50 and rarely found at PR75 in the cortex of control roots. The aerenchymal area at PR75 increased in the presence of the ethylene precursor ACC or a natural auxin IAA. On the other hand, MeJA differentially acted on non-submerged and submerged roots. Exogenously applied MeJA suppressed the aerenchyma formation in non-submerged roots. When the primary root was submerged, aerenchymal area expanded prominently. The submergence-induced aerenchyma formation was amplified with MeJA. Lateral root primordia have been known to inhibit aerenchymal death of surrounding cells. All the three hormones stimulating aerenchyma formation as described above did not restore the inhibition caused by lateral root primordia, suggesting that the inhibitory step regulated by lateral root primordia can be located after hormonal signaling steps.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.4
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• pp.27-60
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• 2012

Jeong-Kuk Wonjong Gongsin-Nokgwon(靖國原從功臣錄券) is a book that recorded the titles of position and the names of retainers who helped the King Jung-Jong's revolution. This study aims to analyze the existing two books of Jeong-Kuk Wonjong Gongsin-Nokgwon, in order to figure out the reasons of grant, structure and forms, the characteristics of meritorious retainers' official positions and social status. The result shows that, Jeong-Kuk Wonjong Gongsin-Nokgwon was printed with the Choju-Gapin (初鑄甲寅) letter metal movable types. This book was composed of the beginning(卷首), the body(本文), and the end(卷末). Jeong-Kuk Wonjong meritorious retainers formed the total of 3,340 persons(1st grade: 418 persons, 2nd grade: 1,016 persons, 3rd grade: 1,906 persons) with 432 official titles. Also an analysis of their social status confirmed that 2,376 persons were "Yang-ban(兩班)" which constituted the largest group(2,376 persons: 71.1%), "Jung-in(中人)" were second group(494 persons: 14.8%), "Yang-in(良人)" were 272 persons(8.2%) and "Chun-in(賤人)" were 198 persons(5.9%).

• Fire Science and Engineering
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• v.27 no.5
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• pp.75-79
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• 2013

Application of the left lateral tilt position has been recommended during cardiopulmonary resuscitation (CPR) of pregnant patients. However, the left lateral tilt could displace the left ventricle (LV) besides the gravid uterus and may compromise the cardiac pump mechanism of CPR. Thus, we investigated the effect of left lateral tilt on the spatial relationship between the anterior-posterior axis (AP axis), which represents the direction of sternal displacement during CPR, and the LV. We retrospectively reviewed the medical records and multidetector computed tomography (MDCT) scans of 90 patients who underwent virtual gastroscopy using MDCT. Virtual gastroscopy was performed with the patient both in the left lateral tilt position and in the supine position. On an axial image showing the maximal area of the LV, the angle between the AP axis and the LV axis ($Angle_{AP-LV}$), the shortest distance between the AP axis and the mid-point of LV cavity ($D_{AP-MidLV}$) and the shortest distance between the AP axis and the LV apex ($D_{AP-Apex}$) were measured. In the supine scans, the LV was situated on the left side of the AP axis in 87 patients (96.7%). On the left lateral tilt scans, the mean tilt angle was $43.4{\pm}11.0^{\circ}$. $D_{AP-MidLV}$ and $D_{AP-Apex}$ were significantly longer in the left lateral tilt position (p<0.001), but $Angle_{AP-LV}$ was comparable between the positions. This study indicates that the left lateral tilt position may compromise the cardiac pump mechanism of chest compression in pregnant cardiac arrest patients.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.4
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• pp.397-405
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• 2008

The position accuracy is primarily dependent on the satellite position and signal delay caused by several elements. To know the effect of the delay on the estimated positions, we simulated GPS raw data (RINEX) with GPS errors using Bernese ver5.0. GPS errors used in this paper are Ionospheric delay, Cycle slip, Troposphere, DOP and Random error. If the baseline is short, the position error according to TEC is not large, since the ionospheric delay effect can be removed by ion-free combination. However, if the baseline is long, 3 dimensional position error up to 10cm is occurred. The 3D position error of coordinates with cycle slip is hardly ever changed up to 60% of cycle slip. Because the simulated cycle slips are equally distributed on satellites, the positioning was not seriously affected by the cycle slip. Also, if percentage of cycle slip is 60%, three dimensional error is sharply increased over 1m. The position error is calculated by using the observation data (2 hours) which was selected by DOP less than 3. And its accuracy is more improved about $3{\sim}4cm$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.3
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• pp.305-315
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• 2010

This research aims to develop a method to determine the 3D coordinates of an object point from overlapping omni-directional images acquired by a ground mobile mapping system and assess their accuracies. In the proposed method, we first define an individual coordinate system on each sensor and the object space and determine the geometric relationships between the systems. Based on these systems and their relationships, we derive a straight line of the corresponding object point candidates for a point of an omni-directional image, and determine the 3D coordinates of the object point by intersecting a pair of straight lines derived from a pair of matched points. We have compared the object coordinates determined through the proposed method with those measured by GPS and a total station for the accuracy assessment and analysis. According to the experimental results, with the appropriate length of baseline and mutual positions between cameras and objects, we can determine the relative coordinates of the object point with the accuracy of several centimeters. The accuracy of the absolute coordinates is ranged from several centimeters to 1 m due to systematic errors. In the future, we plan to improve the accuracy of absolute coordinates by determining more precisely the relationship between the camera and GPS/INS coordinates and performing the calibration of the omni-directional camera