• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.95-101
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• 2003

The purpose of this study was to evaluate the patterns of skeletal changes of proximal and distal segments after one jaw surgery and two jaw surgery with posterior impaction using SSRO on mandible in order to determine the skeletal origin of relapse and compare the stability of surgical methods in anterior open bite. The points and lines from lateral cephalometrics were measured before, after surgery, and at least 6-month follow up period. And then, the positional change of the proximal and distal segment were evaluated respectively. The results obtained were as follows; In cases of two jaw surgery, the results were stabler because they had less relapse factors. In cases of one jaw surgery, the value of APD were increased but it didn't relapse to the original value. Both of proximal and distal segments were responsible for the relapse tendency. But in one jaw surgery, the rotation of proximal segment was more responsible, and in two jaw surgery, the rotation of distal segment was.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.659-665
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• 2016

In this paper, we propose a novel position accuracy enhancement method of a low-end GPS using digital map information. The latest digital map has various kinds of information on geographical features. The proposed method uses position information of lane marks among the geographical features. We define the position information of lane marks as the reference points. The position information of a low-end GPS acquired for a period of time is defined as the source points. In the proposed method, rotation and translation matrices between the reference and the source points are calculated by using an Iterative Closest Point(ICP) algorithm. The source points are transformed by the obtained rotation and translation matrices. Finally, the transformed source points are projected on the reference points. Through these processes, the position accuracy of a low-end GPS is ultimately enhanced. To verify the proposed method, the various real experimental results are presented.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.357-361
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• 2013

A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses' interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.

• PNF and Movement
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• v.15 no.1
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• pp.97-104
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• 2017

Purpose: This study seeks to determine the effect of a lower extremity strengthening exercise that uses proprioceptive neuromuscular facilitation (PNF) on the gait and balance ability of a stroke patient. Methods: In this case study, a lower extremity strengthening exercise that used PNF was performed by the subject for 30 minutes 4 times per week for a 4-week period alongside typical rehabilitation therapy. The lower extremity pattern used flexion-abduction-internal rotation with knee flexion, extension-abduction-internal rotation, bilateral leg extension pattern. The 10 m walk test and 6 minute walk test were used to assess gait ability. The Berg balance scale was used to assess balance ability. Results: After the intervention, the time for the 10 m walk test decreased by 5.72 sec, the distance for the 6 minute walk test decreased by 20 meters, and the score on the Berg balance scale improved by 7 points, which indicates the effectiveness of this therapy for stroke patients. Conclusion: The results of this study indicate that a lower extremity strengthening exercise using PNF can improve the gait ability and balance ability of stroke patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.254-259
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• 2019

Objectives: Crown-root fracture and cervical caries in maxillary premolars constitute a challenge in cases of subgingival placement of restoration margins. Surgical extrusion has been practiced successfully in permanent anterior teeth. The aim of the present retrospective study was to assess the clinical outcome of surgical extrusion after orthodontic extrusion in maxillary premolars. Materials and Methods: Twenty-one single, tapered root maxillary premolars with subgingival crown-root fracture or caries were included. Presurgical orthodontic extrusion was performed on all teeth to prevent root resorption. Extent of extrusion and rotation was determined based on crown/root ratio. The postoperative splinting period was 7 to 14 days. Clinical and radiographic examination was performed at an interval of 1, 2, and 3 months. Results: After the mean follow-up of $41.9{\pm}15.2months$, failure was observed as increased mobility in 3 of 21 cases. No significant difference was observed in the outcome of surgical extrusion based on tooth type, age, sex, $180^{\circ}$ rotation, or time for extraction. Furthermore, marginal bone loss was not observed. Conclusion: Surgical extrusion of maxillary premolars can be a possible therapeutic option in cases of subgingival crown-root fracture.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.196.2-196.2
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• 2016

The design and development procedures of SF6 gas circuit breakers are still largely based on trial and error through testing although the development costs go higher every year. The computation cannot cover the testing satisfactorily because all the real processes arc not taken into account. But the knowledge of the arc behavior and the prediction of thermal plasmas inside SF6 interrupters by numerical simulations are more useful than those by experiments due to the difficulties to obtain physical quantities experimentally and the reduction of computational costs in recent years. In this paper, in order to get further information into the interruption process of a SF6 self-blast interrupter, which is based on the combination of thermal expansion and arc rotation, gas flow simulations with a CFD-arc modeling are performed during the whole switching process such as high-current period, pre-current zero period, and current-zero period. Through the complete work, the temperature of residual arcs as well as the breakdown index after current zero should be a good criterion to predict the dielectric capability of interrupters.

• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.409-414
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• 2004

A signal processing system of long period grating sensor that works in the optical wavelength domain is proposed. The system is based on a wavelength-swept semiconductor light source that includes an SLD and a F-P tunable filter. The hysteresis effects of PZT in the F-P filter is compensated by using an etalon filter and an athermal Fiber Bragg Grating. The detected signals from the photodiode are transmitted to a computer using an A/D converter and the result of the process is displayed in the monitor.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.449-456
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• 2013

Purpose: The present study aimed to investigate the effects of corneal eccentricity and shape on the rotational pattern of toric soft lens by the postural change of lens wearers. Methods: The corneal eccentricity of 41 eyes (aged 20s) having -1.0 D with-the-rule corneal astigmatism (WRCA) was measured, and then toric soft lenses were fitted with the amount of total astigmatism. In lying and straight postures, the rotation of toric soft lenses was recorded by a camera attached to slitlamp and analyzed. Results: Most toric soft lens designed with accelerated stabilization rotated to the temporal direction, which was the lying position direction, regardless of corneal eccentricity, and some lenses rotated to the nasal direction for high corneal eccentricity and corneal type of asymmetric bowtie. There was no correlation between the amount of rotation and corneal eccentricity right after of contact lens wearing in straight and lying posture, however, the amount of rotation was the greater for the cornea with the higher eccentricity after the subjects laying down for some period. The speed of lens rotation started to decrease after the subjects laying down, but the speed was not different according to corneal eccentricity difference. The amount of lens rotation for symmetric and asymmetric bowtie-typed corneas increased more than it for oval-typed cornea, and it was same even with time elapsing. The speed of lens rotation in lying posture was the slowest in asymmetric bowtie-typed cornea compared with other corneal types. Conclusions: From the present study, it was revealed that the rotational pattern of toric soft lens was affected by corneal eccentricity and corneal shape when the wearer's posture changed. Thus, it should be considered for the development of the fitting guideline and the design of toric soft lens.

• Clinics in Shoulder and Elbow
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• v.16 no.1
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• pp.27-32
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• 2013

Purpose: The purpose of this study is to evaluate the clinical and radiological outcomes of treatment of humerus shaft simple fracture by minimally invasive percutaneous osteosynthesis (MIPO) technique using locking compression plate (LCP). Materials and Methods: Six patients who were operated for humerus shaft simple fracture from August 2010 to May 2011 were enrolled for this study. We checked the cause of injury and the accompanying injuries and evaluated the operation time, the clinical and radiological period of union, postoperative range of motion of the shoulder and elbow joint, pain, activities in daily living, radiologic alignment, and other complications. Results: The clinical period of bone union was 7.2 weeks on average, and the radiologic period of bone union was 8 weeks on average. Follow-up period was more than 12 months in all cases. The angulation through postoperative alignment was 2.8 degrees in AP view and 2 degrees in lateral view. The postoperative range of motion was 167 degrees in forward flexion, 50 degrees in external rotation, and thoracic vertebra 12 level in internal rotation. The average value of visual analogue scale (VAS) was 1.2 and that of KSS was 91.3. The American Shoulder and Elbow Surgeons' score (ASES) was 26.5 and the UCLA score was 31.5. Conclusion: MIPO technique for the humerus shaft simple fracture showed good functional and radiological outcomes and may be considered as one of the treatment options for humerus shaft simple fracture.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.27-35
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• 2012

Purpose: The present study was conducted to compare any difference caused by pigmentation in the centrations and movement patterns on the cornea between circle and soft contact lens with identical material and parameters during lens wearing. Methods: Soft and circle contact lenses with identical material and parameters were applied to twenty eyes with normal tear volume for 3 hrs a day during a total of 5 days and then their lens centrations, the moving distances and rotations by repeat blinking were compared. Results: The lens centration beyond the fitting criteria was shown in initial wears of both soft contact lens and circle contact lens. However, the centration of soft contact lens was changed to the pupil center for being suitable to the fitting criteria with longer wearing time. On the other hand, the decentration of circle contact lens in the horizontal direction was still presented even with longer wearing time. The moving distances of soft contact lens and circle contact lens decreased with the expand of lens wearing but were not significantly different between total wearing period and daily wearing time. The rotation of circle contact lens by repeat blinking was significantly different from that of soft contact lens even when the wearing period was extended. Conclusions: We revealed that the lens centration and movement of circle contact lens on cornea were different from those of regular soft contact lens resulting in bigger difference with the expand of wearing period in the study.