• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.565-606
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• 1993

The purpose of this study was to evaluate the change of before and after treatment of anterior openbite malocclusions treated by Multiloop Edgewise Archwire technique. The openbite sample consisted of 4 male and 12 female adults, treated with nonextraction or third molar extraction. The normal sample consisted of 58 subjects, which have pleasing facial profile and normal occlusion and no experience of orthodontic or prosthodontic treatment. The 58 subjects of normal sample were subdivided by cephalemetric vertical relationship of face. The 40 subjects, cephalometric vertical relationship of face was in normal range, classified as Normal Sample group 1. The 18 subjects, increased cephalometric vertical relationship of face, classified as Normal Sample group 2. The computerized cephalometric analysis was accomplished with 50 reference points for 22 skeletal measurements, 46 dentoalveolar measurements, 8 soft tissue measurements. Statistical analysis of the data was carried out with paired t-test, Student's t-test, and DUNCAN test using SAS(PC version), The results were as follows : 1. There were no statistically significant differences in skeletal measurement between before and after treatment. The major changes were in dentoalveolar region. 2. After treatment, the long axis of maxillary and mandibular posterior teeth were distally tipped-back, and uprighted to bisected occlusal plane. The interincisal angle was increased. 3. There were no statistically significant increase in the upper posterior dental height and statistically significant decrease in the lower posterior dental height. The upper anterior dental height was increased, but there was no statistically significant increase in the absolute upper anterior dental hight. The lower anterior dental height was increased. 4. After treatment, the maxillary occlusal plane to palatal plane angle and the mandibular occlusal plane to mandibular plane angle were statistically significant increased. Then, there were no statistically significant difference between after treatment group and normal sample group 2. 5. After treatment, the percentage of upper lip length to upper anterior dental height was decreased. Then, There were no statistically significant difference between after treatment group and normal sample group 2.

• The korean journal of orthodontics
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• v.43 no.5
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• pp.218-224
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• 2013

Objective: To examine the effect of bite force on the displacement and stress distribution of orthodontic mini-implants (OMIs) in the molar region according to placement site, insertion angle, and loading direction. Methods: Five finite element models were created using micro-computed tomography (microCT) images of the maxilla and mandible. OMIs were placed at one maxillary and two mandibular positions: between the maxillary second premolar and first molar, between the mandibular second premolar and first molar, and between the mandibular first and second molars. The OMIs were inserted at angles of $45^{\circ}$ and $90^{\circ}$ to the buccal surface of the cortical bone. A bite force of 25 kg was applied to the 10 occlusal contact points of the second premolar, first molar, and second molar. The loading directions were $0^{\circ}$, $5^{\circ}$, and $10^{\circ}$ to the long axis of the tooth. Results: With regard to placement site, the displacement and stress were greatest for the OMI placed between the mandibular first molar and second molar, and smallest for the OMI placed between the maxillary second premolar and first molar. In the mandibular molar region, the angled OMI showed slightly less displacement than the OMI placed at $90^{\circ}$. The maximum Von Mises stress increased with the inclination of the loading direction. Conclusions: These results suggest that placement of OMIs between the second premolar and first molar at $45^{\circ}$ to the cortical bone reduces the effect of bite force on OMIs.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.433-439
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• 2007

The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.154-160
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• 2018

When making conventional removable partial denture for the remaining teeth where the remaining teeth are only on one side, rotation of the denture occurs -in function- on the axis of the connected remaining teeth. If the edentulous portion is long, it becomes harder to obtain retention and stability for the abutment as the importance of the mucous membrane support is elevated. Such movements of denture decrease denture retention and stability, put excessive stress on the abutment, and give bad influence on periodontal health. Therefore, additional implant placement can be of a good choice in gaining additional retention and stability for partial denture. Thus hereby we report this clinical case as successful results were obtained by placing implants symmetrical to the remaining teeth and putting implant-supported surveyed crowns on the implants, allowing the partial denture to be designed to accept varying components and to have suitable path of insertion.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.5
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• pp.442-449
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• 1984

Turbulent jet flow has been studied in many ways; a plane jet, a rectangular jet, an annular jet, a round jet, a wall jet, a parallel jet, a valve jet, a cross jet, a slit jet and etc. In this report, a 45.deg. cross jet flow was tried by using two same dimensioned nozzels(dia..phi.20)which were set up at the exit of the subsonic wind tunnel. Each jet flows to the direction of 22.5.deg. to the axis of downstream of the mixed flow. The centerline of each jet meets at the distance of 217.3mm and their mixing flow could be imagined to develop beyond that distance, so the measurement was effectuated at X/X$_{0}$=1.2-1.5. The section of the mixed flow a elliptic circle which is formed by the 22.5.deg. inclined flows to the X direction. This experimental study aimed at the investigation of the turbulent mixing process of two jets; the mean velocities, the turbulent shear stresses, the correlation coefficients, and the momentum were respectively measured. The mean velocity distribution profiles of the down-stream component measured in the Y direction coincide well with the empirical equation of Gortler and those measured in the Z direction agree with the equation of H. Schlichting. Other mean velocities V over bar and W over bar components were randomly distributed. The higher values with same order of the intensity of turbulence were largely distributed at the central part of the flow. The momentum was decreased up to 70% by the shock losses and the development of intense turbulences, but it kept its value constantly beyond X/d=14. Two-channel hot-wire anemometer systems (model 1050 series), X-type hot-wire made of tungsten (dia. .phi.e.mu.m, long 3mm, model 0252 T5), a computer(model HP 9845B0, and a plotter (model HP 9872C) were used for the experiments and the analyses.s.

• Biomedical Science Letters
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• v.15 no.3
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• pp.249-255
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• 2009

All living things have been developed efficient strategies to cope with external and internal environmental changes via a process termed 'homeostasis'. However, chronic prenatal maternal stress may significantly contributes to pregnancy complications by disturbing hypothalamic-pituitary-adrenal (HPA) axis and the automatic nervous system (ANS), and results in unfavorable development of the fetus. Dysregulation of these two major stress response systems lead to the increased secretion of the glucocorticoids (GCs) which are known to be essential for normal development and the maturation of the central nervous system. As Hox genes are master key regulators of the embryonic morphogenesis and cell differentiation, we aimed to determine the effects of dexamethasone, a potent synthetic glucocorticoid, on gene expression in mesenchymal stem cell C3H10T1/2. Analysis of 39 Hox genes based on reverse transcription PCR (RT-PCR) method revealed that the expression patterns of Hox genes were overall upregulated by long dexametasone treatment. These results indicate that maternal stress may have a deleterious effect on early developing embryo through the stress hormone, glucocorticoid.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.232-237
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• 2013

A newly developed fall detection algorithm using the HMM (Hidden Markov Model) extracted from the video is introduced. To distinguish between the fall from personal difference fall pattern or the normal activities of daily living (ADL), HMM machine learning algorithm is used. For getting fall feature vector of video, the motion vector from the optical flow is applied to the PCA (Principal Component Analysis). The combination of the angle, ratio of long-short axis, velocity from results of PCA make the new fall feature parameters. These parameters were applied to the HMM and the results were compared and analyzed. Among the newly proposed various kinds of fall parameters, the angle of movement showed the best results. The results show that this parameter can distinguish various types of fall from ADLs with 91.5% sensitivity and 88.01% specificity.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.55-63
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• 2005

Direct Georeferencing(DG) Is based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The methods can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. Hence, as long as securing Digital Elevation Model (DEM), it is feasible to generate digital orthophotos without performing the aerial triangulation with Ground Control Point (GCP) surveying. In this study, the DEM is automatically generated by using a image matching technique based on aerial photos and exterior orientation parameters. This is followed by producing an orthophoto from these results. Finally, accuracy analysis of the georeferencing technique for generating orthoimage indicates that RMS errors of 62cm and 76cm occurred at the X and the Y axis, respectively. This means that the results fulfill the demanding accuracy of the 1:5000 digital map. Hence, it is possible to conclude from this study that the direct georeferencing based orthoimage generation method is able to effectively digital map update.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.295-306
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• 2013

The purpose of this study was to provide high school male shot putters training methods of gliding and delivery motion through comparative analysis of kinematic characteristics. To accomplish this purpose, three dimensional motion analysis was performed for the subjects(PKC, KKH, YDL) who participated in high school male shot putter competition on 92nd (2011), 93rd (2013) National Sports Festival. The subjects were filmed by four Sony HXR-MC2000 video cameras with 60 fields/s. The three-dimensional kinematic data of the glide, conversion and delivery phase were obtained by Kwon3d 3.1 version. The data of the shoulder rotational angles and projection angles were calculated with Matlab R2009a. The following conclusions had been made. With the analysis of the gliding and stance length ratio, the gliding length was shorter at the TG than the SG with short-long technique but the gliding and stance length ratio was 46.8:53.2% respectively. The deviation of the shots trajectory from APSS(Athlete-plus-shot-system) revealed that the PKC showed similar to "n-a-b-c-I" of skilled S-shape type, KKH and YDL showed "n-a-d-f-I'" of unskilled type. Furthermore, they showed smaller radial distance from the central axis of the APSS and the shots were away from the linear trajectory. From this characteristics, The PKC who performed more TG than SG had shorter glide with S-shape of APSS(skilled type) showed the better record than others with technical skill. But KKH and YDL had bigger glide ratio with "n-a-d-f-I'" of unskilled type and improved their records with technical factor. The projection factor had an effect on the record directly. Because PKC maintained more lower glide and transition posture with momentum transfer through COG's rapid horizontal velocity respectively the subject possessed the characteristics of high horizontal and vertical velocity with large turning radius from shot putter to APSS.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.38.1-38.1
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• 2010

McDonald 2.1m Otto Struve Telescope is located in the Davis Mountains, 450 miles west of Austin, Texas. The telescope was built in 1938, but it is still in demand today. CQUEAN (Camera for QUasar in Early uNiverse) will be attached on this telescope and perform Y-band imaging observations. Dynamics study of the telescope shows that tracking errors are 0.1 arcsec/100sec in declination direction and 0.4 arcsec/100sec in R.A. direction. In order to allow a long exposure (> a few minutes) of a target field, we are making auto-guiding system for the 2.1m telescope. The auto-guiding system of CQUEAN will be connected with TCS of the telescope. The expected number of stars on the CCD field (2.97 square arcminutes) is about 1.2 stars which are brighter than magnitude 17.5 in 2.97 square arcminutes. For more effective observation, we plan to implement moving mechanism in guiding system so that guide CCD camera can see wider off-axis fields.