• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.41-48
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• 2002

Anisotropy of stiffness, from extremely small strains to post-failure strains, of isotropically consolidated air-pluviated sands in plane strain compression was studied by using the newly developed instrumentation fur small strain measurements, Seven types of sand of world-wide origins were tested, which have been extensively used for research purposes. Stress-strain relationships for a wide range of strain from about 0.0001% to the peak were obtained by measuring axial and lateral strains locally free from the effects of bedding and membrane penetration errors at the specimen boundaries. The result showed that the relationship between the principal stress ratio and the principal strain increment ratio was constant, being rarely affected by the over-consolidation ratio and the confining pressure. Although in the small strain the anisotropy hardly affected the relationship between the principal stress ratio and the principal strain increment ratio, the K value around the peak varied according to the $\delta$ value. In general, Rowe\`s stress-dilatancy equation works fairly well from the small strain to the peak.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.5
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• pp.422-426
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• 2005

Purpose : The purpose of this study was to investigate the vertical stability after BSSRO surgery in skeletal class III malocclusion patients with mild anterior open bite and to present a method to increase the stability. Materials and methods : 36 patients, 11 male and 25 female, who received BSSRO surgery with the diagnosis of skeletal class III with anterior open bite at the Department of Oral and Maxillofacial Surgery in Samsung Medical Center, from January 2002 to August 2003, were selected for this study. The patients were between 18 to 45 years of age. Preoperative and postoperative (immediate, 6 months, and 1 year after operation) lateral cephalograms were compared to evaluate the vertical stability by measuring the distance of nasion-menton, mandibular plane angle, and overbite. Results : The nasion-menton distance decreased by 1.65mm immediately after the operation in comparison to the preoperative value. This distance further decreased by 0.60 mm at 6 months and 1.06mm at 1 year after the operation. The mandibular plane angle increased after the operation and further increased at 6 months and 1 year. The amount of overbite increased by the operation was 2.34mm and an additional increase of 0.70mm at 6 months and 0.94mm at 1 year were shown. Conclusion : Clinically, none of the patients showed relapse of anterior open bite and the vertical stability is highly influenced by orthodontic treatment after the operation. In this study, BSSRO surgery is considered to be a rather reliable procedure that restores stability to skeletal class III malocclusion patients with slight anterior open bite.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.503-510
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• 1999

The purpose of this study is to investigate the negative effects of cervical pull headgear and to compare the differences between the two groups of growers-vertical grower and horizontal grower group-which are classified by the posterior-anterior facial height ratio. Initial and final lateral cephalograms were taken for 26 patients including 15 vertical growers and 11 horizontal growers ; also, 3 angular measurements and 4 linear measurements were evaluated. The following results were found. 1. The palatal plane was tipped anteroinferiorly in the vertical grower group. 2. The posterior facial height/anterior facial height ratio was increased in the horizontal grower group. 3. The Mandibular plane angle remained stable on both groups. 4. There was no significant difference between the two groups in the amount of maxillary molar extrusion.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.485-494
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• 2005

Maxillary anterior teeth were intruded and lingually root torqued with two maxillary anterior microimplants between the lateral incisors and canines. Overerupted maxillary canines were intruded with two other microimplants between the maxillary canines and first premolars. Maxillary posterior teeth and canines were distalized, then the maxillary incisors were retracted with two maxillary posterior microimplants between the first and second molars. The mandibular anterior teeth were intruded and the mandibular posterior teeth were extruded with conventional method such as anterior bite plane, intrusion arch and Class II elastics. The mandible moved slightly forward after the correction of deep bite and retroclination of the upper incisors. Consequently, microimplant anchorage (MIA) provided absolute anchorage for simultaneous correction of Class II canine and molar relationships and deep overbite.

• Journal of Korean Foot and Ankle Society
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• v.3 no.1
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• pp.19-25
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• 1999

The purpose of this study Is to assess the retained range of motion[RROM] of the foot after arthrodesis of the ankle joint, which might help designing the angle of arthrodesis. We reviewed the results including the RROM in 14 cases of ankle arthrodesis. Underlying causes included trauma group(six posttraumatic arthritis) and disease group(three osteoarthritis, three Charcot joints, one chronic synovitis and one pyogenic arthritis). We measured the RROM on the lateral roentgenograms of the ankle in full dorsiflexion and plantarflexion, The results were assessed by the AOFAS hindfoot scale[score]. The RROM in sagittal plane was $23.4{\pm}5.3$ degrees and the score was 71.5 points on average. The RROM and the score were $26.8^{\circ}{\pm}2.1$, 81.2 points respectively in trauma group and $20.8^{\circ}{\pm}5.6$, 64.3 points in disease group; $26.6^{\circ}{\pm}2.3$, 83.4 points in cases younger than 40 years of age and $21.6^{\circ}{\pm}5.7$, 64.9 points in the older. The mean score was 77.3 points in cases whose RROM were $24^{\circ}$ or more and 61 points in cases of less RROM; 69.6 and 73.4 points in cases with and without adjacent degenerative arthritis respectively. The score was 69.7, 73.3 and 71.5 points in cases whose angle of arthrodesis was in dorsiflexion, neutral, plantarflexion respectively. In conclusion, after ankle arthrodesis RROM of the foot was $23.4^{\circ}$, and the more the RROM, the higher the score. In cases with sufficient amount of RROM, the angle of fusion on sagittal plane might not influence the result significantly.

• Korean Journal of Biological Psychiatry
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• v.22 no.1
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• pp.14-19
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• 2015

Objectives The purpose of this study is to find the cephalometric variables which are significantly correlated with the apnea-hypopnea index (AHI) in suspected Korean obstructive sleep apnea (OSA) patients. Methods We examined lateral cephalogram and attended-full night laboratory polysomnography of the 40 participants who complained of OSA symptoms. The correlation analysis was conducted to find the cephalometric variables which are significantly correlated with the AHI. Results The correlation analysis showed that the higher AHI was associated with the longer distance between hyoid and mandibular plane (p = 0.023), the longer distance between C3 and hyoid (p = 0.014), the longer tongue length (p = 0.003), the larger inferior tongue area (p = 0.008), the larger anterior displacement of the hyoid bone (p = 0.024), the longer distance between posterior nasal spine and the tip of the soft palate (p = 0.021), and the larger cross-sectional area of soft palate (p = 0.001) of cephalogram in erect position. The higher AHI was correlated with the longer distance between hyoid and mandibular plane (p = 0.008), the longer tongue length (p = 0.037), the larger inferior tongue area (p = 0.013), the thicker uvula (p = 0.004), the longer distance between retrognathion and hyoid (p = 0.025), and larger cross-sectional area of soft palate (p = 0.001) of cephalogram in supine position. Conclusions The present preliminary results showed the candidate measurements of cephalogram which are significantly correlated with the AHI in suspected OSA.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.407-417
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• 2017

RC shear walls are considered one of the main lateral resisting members in buildings. In recent years, FRP has been widely utilized in order to strengthen and retrofit concrete structures. A number of experimental studies used CFRP sheets as an external bracing system for retrofitting of RC shear walls. It has been found that the common mode of failure is the debonding of the CFRP-concrete adhesive material. In this study, behavior of RC shear wall was investigated with three different micro models. The analysis included 2D model using plane stress element, 3D model using shell element and 3D model using solid element. To allow for the debonding mode of failure, the adhesive layer was modeled using cohesive surface-to-surface interaction model at 3D analysis model and node-to-node interaction method using Cartesian elastic-plastic connector element at 2D analysis model. The FE model results are validated comparing the experimental results in the literature. It is shown that the proposed FE model can predict the modes of failure due to debonding of CFRP and behavior of CFRP strengthened RC shear wall reasonably well. Additionally, using 2D plane stress model, many parameters on the behavior of the cohesive surfaces are investigated such as fracture energy, interfacial shear stress, partial bonding, proposed CFRP anchor location and using different bracing of CFRP strips. Using two anchors near end of each diagonal CFRP strips delay the end debonding and increase the ductility for RC shear walls.

• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.437-444
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• 2012

The purpose of this study was to suggest appropriate human model for ergonomic evaluation considering working postures on 3D space. Background: Traditionally extreme design rules have been widely utilized at the stage of designing products. Body size of 5th percentile and 95th percentile in stature has been generally selected for controllability and clearance evaluation, respectively. However, these rules had limitations in reflecting working posture in ergonomic evaluation. Method: In order to define working posture on 3D space, not only sagittal plane but also lateral plane was considered. Kinematic linkage body model was utilized for representation of working posture. By utilizing the anthropometric data of 2,836 South Korean male populations, the point cloud for end points of linkage models was derived. The individuals who were lacking in certain controllability were selected as human models for the evaluation. Result: In case of standing posture it was found that conventional approach is proper for all controllability evaluations. Contrary to standing posture, tall people had less controllability on control location below shoulder point in sitting posture. Conclusion: From the derived proper range on controllability, ergonomic evaluation rule was suggested according to working posture especially in standing and sitting. Application: The results of the study are expected to aid in selection of appropriate human model for ergonomic evaluation and to improve the usability of products and work space.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.38-42
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• 2017

Schwannomas are mostly solid tumors, some of which may contain cystic degenerations or hemorrhages. However, a schwannoma seen as a purely hemorrhagic cystic tumor is very rare. A 63-year-old woman was referred to the hospital due to a slow-growing mass (present for about 5 years) on her right thigh. She complained about vague pain but without neurologic symptoms such as numbness or tingling sensations. MR images showed an oval lesion with defined margins surrounded by the rectus femoris, vastus lateral, and the vastus intermedius. It was characterized as a multilocular cystic lesion composed of hemorrhagic fluid. In addition, the benign hemorrhagic cystic lesion was differentially diagnosed by radiological techniques as a hemorrhagic ganglion cyst. The lesion was surgically excised and, based on pathological features, was diagnosed as being a schwannoma. We report a purely hemorrhagic cystic schwannoma located in an intermuscular plane.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.243-251
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• 2002

Synthetic zinc wave employs Pulsed plane wave as transmit beam with linear time delay curve. The received echoes in different transmit directions at different transmit times are superposed at imaging Points with Proper time delay compensation using synthetic focusing scheme. This scheme. which uses full aperture in transmit, obtains a high SNR image, and also features high lateral resolution by using two way dynamic focusing at all imaging depths. In this Paper, we consider the Problems in realization of synthetic zinc wave. Also. we have applied the scheme to obtain phantom and in-vivo images using a linear array of 5 MHz. In phantom test. experimental images show high resolution over a more extended imaging depth than conventional fixed Point transmit and receive dynamic focusing schemes In-vivo images show that the resolution could not overcome conventional focusing systems because of motion blurring and(or) aberration of tissue. but the frame rate tan be increased by a factor of more than 5 compared to conventional focusing schemes. with competitive resolution at all imaging depths .