• 전자공학회논문지 IE
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• v.49 no.1
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• pp.12-17
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• 2012

Fast development of ubiquitous technology prompted the broadening of the related application area. Application of ubiquitous techniques and system into the construction sites may give us many benefits. There are always a lot of hazard situations in construction sites, and the falling is known to have the high accident rate. To prevent the falling, there has been a lot of efforts including safety education and use of safety gears. In this study, we designed, fabricated and tested a system that can monitor the worker's safety and location informations in real time by using the wireless technology of TOA and RSSI. We used ATmegal28 that is popular in the industrial equipments as MCU and NanoPan 5357 module from Nanotron and CC2500 chipset from TI for radio circuits. We also used 3-axis accelerometer and pressure MEMS sensors to obtain the environmental information, and therefore to aquire the informations of the worker's movement and altitude. We used Labview software from National Instrument to monitor and control the system. We developed the system to send the warning alarms to the server operator and the workers when the workers in the danger zone did not wear the safety hook.

• Progress in Medical Physics
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• v.9 no.4
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• pp.207-215
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• 1998

There have been many radiation measurement methods so far among which film dosimetry, TLD, and ion chamber are the most frequently used methods. But this study describes a new radiation measurement method which uses polymer gel and magnetic resonance imaging(MRI). The objective of this study is to fabricate a polymer gel sensitive to radiation and to generate a dose to MRI contrast relationship, and to apply this results to the radiation measurement for the brachytherapy. To do this, 12 cm diameter cylindrical gel phantom was made, and the phantom was irradiated using the 30 mm diameter circular collimator which was used for radiosurgery. And this irradiated phantom was scanned with MRI. To find out the relationship between the radiation dose and the transversal relaxation time, an image processing software(IDL) was used. From this study it is found out that the radiation dose showed linear relationship to the transversal relaxation time of the gel up to 17 Gy($R^2$=0.993) and they had a different relationship above 17 Gy. The dose distributions were calculated using these results for the Ir-192 sources, one for the HDR afterloading system and the other for a 2 mCi seed source. And these calculated dose distributions were compared to the ones from the treatment planning computers. From this study the dose to the irradiated gel's transversal relaxation time relationship was examined, and this result was tried for the measurement of the brachytherapy.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.53-60
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• 2014

Purpose: This study was performed to investigate the incidence and configuration of the bifid mandibular canal in a Korean population by using cone-beam computed tomography (CBCT) imaging. Materials and Methods: CBCT images of 1933 patients (884 male and 1049 female) were evaluated using PSR-9000N and Alphard-Vega 3030 Dental CT units (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan). Image analysis was performed by using OnDemand3D software (CyberMed Inc., Seoul, Korea). The bifid mandibular canal was identified and classified into four types, namely, the forward canal, buccolingual canal, dental canal, and retromolar canal. Statistical analysis was performed by using the chi-squared test and one-way analysis of variance (ANOVA). Results: Bifid mandibular canals were observed in 198 (10.2%) of 1933 patients. The most frequently observed type of bifid mandibular canal was the retromolar canal (n=104, rate: 52.5%) without any significant difference among the incidence of each age and gender. The mean diameter of the accessory canal was 1.27 mm (range: 0.27-3.29 mm) without any significant difference among the mean diameter of each type of the bifid mandibular canal. The mean length of the bifid mandibular canals was 14.97mm(range: 2.17-38.8 mm) with only a significant difference between the dental canal and the other types. Conclusion: The bifid mandibular canal is not uncommon in Koreans and has a prevalence of 10.2% as indicated in the present study. It is suggested that a CBCT examination be recommended for detecting a bifid canal.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.491-500
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• 2005

To test applicability to the Hanwoo traceability system, twenty microsatellite markers were selected and analyzed. MSA, CERVUS, FSTAT, GENEPOP, API_CALC and PHYLIP software was employed serially to estimate heterozygosity, polymorphic information content, F-statistics, identity probability, exclusion probability and genetic distance. Eleven microsatellite markers(TGLA53, TGLA227, ETH185, TGLA122, BM4305, INRA23, ILSTS013, BMS1747, BM2113, BL1009, and ETH3) were selected based on their high heterozygosity values. Identity probability using these markers is one hundred times higher than when using StockMakersTM of Applied Biosystems. This indicates the selected microsatellite markers are appropriate and effective for use in the Hanwoo traceability system. Additionally, estimates of DA genetic distance and pairwise-FST can be utilized to identify genetic relationships between adjacent farms.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.11-20
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• 2016

Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: $18{\pm}0years$, body mass: $64.8{\pm}9.52kg$, height: $173.0{\pm}4.80cm$) and 5 amateur cyclists (age: $20{\pm}0years$, mass: $66.6{\pm}2.36kg$, height: $175.6{\pm}1.95cm$). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, and $360^{\circ}$) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at $360^{\circ}$ from the feet was higher in the amateur cyclists, but accelerations at $90^{\circ}$ and $180^{\circ}$ were higher in the elite cyclists. The amateur cyclists had greater joint angles at $270^{\circ}$ from the ankle and wider knee joint distance at $0^{\circ}$, $180^{\circ}$, and $360^{\circ}$ than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.428-446
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• 1997

Restorative procedures can lead to weakening tooth due to reduction and alteration of tooth structure. It is essential to prevent fractures to conserve tooth. The resistance to fracture of the restored tooth may be influenced by many factors, among these are the cavity dimension and the physical properties of the restorative material. The placement of direct composite resin restorations has generally been found to have a strengthening effect on the prepared teeth. It is the purpose of this investigation to study the relationship between the cavity isthmus and the fracture resistance of a tooth in composite resin restorations. In this study, MO cavity was prepared on maxillary first premolar. Three dimensional finite element models were made by serial photographic method and isthmus(1/4, 1/3, 1/2 of intercuspal distance) were varied. Two types of model(B and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall and R model was left unfilled. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed the displacement, 1 and 2 direction normal stress and strain with FEM software ABAQUS Version 5.2 and hardware IRIS 4D/310 VGX Work-station. The results were as follows : 1. Displacement of buccal cusp in R model occurred and increased as widening of the cavity, and displacement in B model was little and not influenced by cavity width. 2. There was a significant decrease of stress resulting in increase of fracture resistance in B model when compared with R model. 3. With the increase of the isthmus width, B model showed no change in the stress and strain. In R model, the stress and strain increased both in the area of buccal-pulpal line angle and the buccal side of marginal ridge, therefore the possibility of crack increased. 4. The stress and strain were distributed evenly on the tooth in B model, but in R model, were concentrated on the buccal side of the distal marginal ridge and buccal-pulpal line angle, therefore the possibility of fracture increased.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.335-340
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• 1997

Fluorescence in situ hybridization (FISH) techniques allow the enumeration of chromosome abnormalities and from a great potential for many clinical applications. In order to produce quantitative and reproducible results, expensive tools such as a cooled CCD camera and a computer software are required. We have developed a Chromosome Image Processing System (Chips) using FISH that allows the detection and mapping of the genetic aberrations. The aim of our study, therefore, is to evaluate the capabilities of our original system using a black-and-white video camera. As a model system, three repetitive DNA probes (D18Z1, DXZ1, and DYZ3) were hybridized to variety different clinical samples such as human metaphase spreads and interphase nuclei obtained from uncultured peripheral blood lymphocytes, uncultured amniocytes, and germ cells. The visualization of the FISH signals was performed using our system for image acquisition and pseudocoloring. FISH images were obtained by combining images from each of probes and DAPI counterstain captured separately. Using our original system, the aberrations of single or multiple chromosomes in a single hybridization experiment using chromosomes and interphase nuclei from a variety of cell types, including lymphocytes, amniocytes, sperm, and biopsied blastomeres, were enabled to evaluate. There were no differences in the image quality in accordance with FISH method, fluorochrome types, or different clinical samples. Always bright signals were detected using our system. Our system also yielded constant results. Our Chips would permit a level of performance of FISH analysis on metaphase chromosomes and interphase nuclei with unparalleled capabilities. Thus, it would be useful for clinical purposes.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.15-22
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• 2003

Seismic design codes developed taking into account the strong earthquakes may result in unnecessary economical loss in the low seismic area, and the importance of the performance based design considering the soil-structure interaction is recognized for the reasonable seismic design. In this study. elastic and inelastic seismic response analyses of a single degree of freedom system on the soft soil layer were performed considering the nonlinearity of the soil for the 1 weak earthquakes scaled to the nominal peak accelerations of 0.07g and 0.11g. The seismic response analyses were performed in one step applying the earthquake motions to the bedrock, utilizing a pseudo 3-D dynamic analysis software of the soil-structure system. The study results indicated that seismic response spectra of a system assuming the rigid base or the linear soil layer does not represent the true behavior of a structure-soil system, and it is necessary to take into account the nonlinear soil-structure interaction effects and to perform the performance based seismic design for the various soil layers, having different characteristics, rather than to follow the routine design procedures specified in the design codes for the reasonable seismic design. The nonlinearity of the soft soil excited with the weak seismic motions also affected significantly on the elastic and inelastic seismic response spectra of a system due to the nonlinear soil amplification of the earthquake motions, and it was pronounced especially for the elastic response spectra.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.111-123
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• 2023

The slope of an open cut tunnel is located above the exit of the Leijia tunnel on the Changgan high-speed railway. During the excavation of the open cut tunnel foundation pit, the slope slipped twice, a large landslide of 92500 m³ formed. The landslide body and unstable slope body not only caused the foundation pit of the open cut tunnel to be buried and the anchor piles to be damaged but also directly threatened the operational safety of the later high-speed railway. Therefore, to study the stability change in the slope of the open cut tunnel under heavy rain and excavation conditions, a 3D numerical calculation model of the slope is carried out by Midas GTS software, the deformation mechanism is analyzed, anti-sliding measures are proposed, and the effectiveness of the anti-sliding measures is analyzed according to the field monitoring results. The results show that when rainfall occurs, rainwater collects in the open cut tunnel area, resulting in a transient saturation zone on the slope on the right side of the open cut tunnel, which reduces the shear strength of the slope soil; the excavation at the slope toe reduces the anti-sliding capacity of the slope toe. Under the combined action of excavation and rainfall, when the soil above the top of the anchor pile is excavated, two potential sliding surfaces are bounded by the top of the excavation area, and the shear outlet is located at the top of the anchor pile. After the excavation of the open cut tunnel, the potential sliding surface is mainly concentrated at the lower part of the downhill area, and the shear outlet moves down to the bottom of the open cut tunnel. Based on the deformation characteristics and the failure mechanism of the landslides, comprehensive control measures, including interim emergency mitigation measures and long-term mitigation measures, are proposed. The field monitoring results further verify the accuracy of the anti-sliding mechanism analysis and the effectiveness of anti-sliding measures.

• Earthquakes and Structures
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• v.26 no.6
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• pp.417-431
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• 2024

The fundamental period of vibration is one of the most critical parameters in the analysis and design of structures, as it depends on the distribution of stiffness and mass within the structure. Therefore, building codes propose empirical equations based on the observed periods of actual buildings during seismic events and ambient vibration tests. However, despite the fact that infill walls increase the stiffness and mass of the structure, causing significant changes in the fundamental period, most of these equations do not account for the presence of infills walls in the structure. Typically, these equations are dependent on both the structural system type and building height. The different values between the empirical and analytical periods are due to the elimination of non-structural effects in the analytical methods. Therefore, the presence of non-structural elements, such as infill panels, should be carefully considered. Another critical factor influencing the fundamental period is the effect of Soil-Structure Interaction (SSI). Most seismic building design codes generally consider SSI to be beneficial to the structural system under seismic loading, as it increases the fundamental period and leads to higher damping of the system. Recent case studies and postseismic observations suggest that SSI can have detrimental effects, and neglecting its impact could lead to unsafe design, especially for structures located on soft soil. The current research focuses on investigating the effect of infill panels on the fundamental period of moment-resisting and eccentrically braced steel frames while considering the influence of soil-structure interaction. To achieve this, the effects of building height, infill wall stiffness, infill openings and soil structure interactions were studied using 3, 6, 9, 12, 15 and 18-story 3-D frames. These frames were modeled and analyzed using SeismoStruct software. The calculated values of the fundamental period were then compared with those obtained from the proposed equation in the seismic code. The results indicate that changing the number of stories and the soil type significantly affects the fundamental period of structures. Moreover, as the percentage of infill openings increases, the fundamental period of the structure increases almost linearly. Additionally, soil-structure interaction strongly affects the fundamental periods of structures, especially for more flexible soils. This effect is more pronounced when the infill wall stiffness is higher. In conclusion, new equations are proposed for predicting the fundamental periods of Moment Resisting Frame (MRF) and Eccentrically Braced Frame (EBF) buildings. These equations are functions of various parameters, including building height, modulus of elasticity, infill wall thickness, infill wall percentage, and soil types.