• The korean journal of orthodontics
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• v.46 no.2
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• pp.73-80
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• 2016

Objective: The purpose of this study was to investigate the static (SFF) and kinetic frictional forces (KFF) in sliding mechanics of hybrid bracket systems that involve placing a conventional bracket (CB) or active self-ligating bracket (ASLB) on the maxillary anterior teeth (MXAT) and a passive SLB (PSLB) on the maxillary posterior teeth (MXPT). Methods: The samples consisted of two thoroughbred types (group 1, anterior-CB + posterior-CB; group 2, anterior-ASLB + posterior-ASLB) and four hybrid types (group 3, anterior-CB + posterior-PSLB-type 1; group 4, anterior-CB + posterior-PSLB-type 2; group 5, anterior-ASLB + posterior-PSLB-type 1; group 6, anterior-ASLB + posterior-PSLB-type 2) (n = 13 per group). After maxillary dentition alignment and maxillary first premolars removal in the stereolithographically-made typodont system, a $0.019{\times}0.025$-inch stainless steel wire was drawn through the right quadrant of the maxillary arch at 0.5 mm/min for 5 min. The SFF and KFF were measured with a mechanical testing machine and statistical analyses were performed. Results: Four different categories of SFF and KFF were observed among all groups (all p < 0.001). Group 1 demonstrated the highest SFF and KFF; groups 4 and 3 were second and third highest, respectively. The fourth category included groups 2, 5, and 6. Placing PSLBs on the MXPT resulted in significant SFF and KFF reductions in cases with CBs on the MXAT, but not in cases with ASLBs on the MXAT. Conclusions: These data might aid in the development of a hybrid bracket system that enables low-friction sliding of an archwire through the MXPT.

• The korean journal of orthodontics
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• v.51 no.2
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• pp.95-104
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• 2021

Objective: To evaluate the trueness and precision of full-arch scans acquired using five intraoral scanners and investigate the factors associated with the dimensional accuracy of the intraoral scan data. Methods: Nine adult participants (mean age, 34.3 ± 8.3 years) were recruited. Four zirconium spheres (Ø 6 mm) were bonded to the canines and the molars. Following acquisition of reference scans using an industrial-grade scanner, five intraoral scanners, namely i500, CS3600, Trios 3, iTero, and CEREC Omnicam, were used to scan the arches. Linear distances between the four reference spheres were automatically calculated, and linear mixed model analysis was performed to compare the trueness and precision of the intraoral scan data among the different scanners. Results: The absolute mean trueness and precision values for all intraoral scanners were 76.6 ± 79.3 and 56.6 ± 52.4 ㎛, respectively. The type of scanner and the measured linear distances had significant effects on the accuracy of the intraoral scan data. With regard to trueness, errors in the intermolar dimension and the distance from the canine to the contralateral molar were greater with Omnicam than with the other scanners. With regard to precision, the error in the linear distance from the canine to the molar in the same quadrant was greater with Omnicam and CS3600 than with the other scanners. Conclusions: The dimensional accuracy of intraoral scan data may differ significantly according to the type of scanner, with the amount of error in terms of trueness being clinically significant.

• Journal of Yeungnam Medical Science
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• v.7 no.2
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• pp.197-202
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• 1990

Mechanical obstruction of the common hepatic duct includes the following causes ; choledocholithiasis, sclerosis, cholangitis, pancreatic carcinoma, cholangiocarcinoma, postoperative stricture, primary hepatic duct carcinoma, enlarged cystic duct lymph nodes, and metastatic nodal involvement of the porta hepatis. Partial mechanical obstruction of the common hepatic duct caused by impaction of stones and inflammation surrounding the vicinity of the neck of the gallbladder had been reported on the "syndrome del conducto hepatico" in 1948 by Mirizzi. Nowadays, this disease was named by Mirizzi syndrome. Mirizzi syndrome is a rare entity of common hepatic duct obstruction that results from an inflammatory response secondary to a gallstone impacted in the cystic duct or neck of the gallbladder. It results from an almost parallel course and low insertion of the cystic duct into the common hepatic duct. In a varient of Mirizzi's syndrome, the cause of the common hepatic duct obstruction was a primary cystic duct carcinoma rather than gallstone disease. A 71-year-old man was admitted with a four-day history of right upper quadrant abdominal pain. Past medical history was unremarkable. On physical examination, the patient had a temperature of $38^{\circ}C$, icteric sclera and right upper quadrant tenderness. Pertinent laboratory findings included WBC 18,000/$cm^2$;albumin 2.6g/dl(normal 3.9-5.1) ; SGOT 183u/L(normal 0-50) ; SGPT167u/L(normal 0-65) ; bilirubin, 8.2mg/dl(normal 0-1) with the direct bilirubin, 4.4mg/dl(normal 0-0.4). Ultrasonography revealed a dilated extrahepatic biliary tree. ERCP showed that the superior margin was angular and more consistent with a calculus causing partial CHD obstruction(Mirizzi syndrome). At surgery a diseased gallbladder containing calculi was found. In addition, there was two calculi partially eroding through the proximal portion of the cystic duct and compressing the common hepatic duct. A cholecystectomy and excision of common bile duct was performed, with Roux-en-Y hepaticojejunostomy. The postoperative course was uneventful.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1240-1247
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• 2019

In this paper, we designed a four-band antenna that can be applied to WLAN and WiMAX systems by designing a microstrip feeding structure, four branch lines and a slit on the ground plane. The proposed antenna is designed with a size of 16.0 mm (W1) × 48.0 mm (L8) on a dielectric substrate of 18.0 mm (W) × 50.0 mm (L) × 1.0 mm(h). and a slit of 2.9 mm (W7) × 4.0 mm (L7) is inserted into the ground plane of 18.0 mm (W) × 18.7 mm (L6). Based on -10 dB production and measurement results, it obtained 60.8 MHz (8,730~9,338 MHz), 310 MHz (2.33~2.64 GHz) in the 2.4 GHz band, 420MHz (3.39~3.81 GHz) in the 3.4 GHz band, and 2,070 MHz (4.62~6.69 GHz) in the 5.0 GHz. In addition, the gain and radiation pattern characteristics of the quadrant band are measured from the measurement results anechoic chamber.

• Archives of Plastic Surgery
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• v.34 no.5
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• pp.628-634
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• 2007

Purpose: Subcutaneous mastectomy has been accepted as a standard for the treatment of gynecomastia. Surgical managements including ultrasound-assisted liposuction(UAL) have had limited success and several combined approaches were tried to find the most effective method. We designed a modified subcutaneous mastectomy, which we call "pan-cake method". The purpose of this study is to evaluate the results of our method for the treatment of gynecomastia. Methods: 16 patients from 16 to 31 years of age having gynecomastia were operated using the pan-cake method. 11 patients were in grade I, and 5 patients were in grade II, no patient were in grade III or IV, according to Rod's classification. The pan-cake method started with modified periareolar incision. We executed subcutaneous dissection first and suprafascial dissection next. After dividing the breast into four equal quadrants, we removed breast tissue from each quadrant as necessary. The operation time for the resection was recorded and the weight of removed parenchyme tissues was measured. Results: All the operations were successful. There were no asymmetries, contour deformities, or irregularities. Only 6 cases needed the combined therapy with ultrasound-assisted liposuction(UAL) because of the step deformities. The average operation time was 24.1 minutes and the average weight of removed breast tissue was 98.1g. All the patients were satisfied with the aesthetic results. Conclusion: We concluded that the pan-cake method is an alternative option for the surgical treatment of gynecomastia, giving good aesthetic results and relatively short operation time.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.17-35
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• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.399-406
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• 2014

This study investigates the structure and operation of the ITER VS converter and proposes a sequence control method for six series-connected VS converters to reduce reactive power. The operation and the proposed sequence control method are verified through RTDS simulation. The ITER VS converter must supply voltage/current to the superconducting magnets for plasma current vertical stabilization, and the four-quadrant operation must proceed without a zero-current discontinuous section. The operation mode of the VS converter is separated into a 12- and 6-pulse circulating current and transition modes according to the size of the load current. The output voltage of the unit VS converter is limited because of the rated voltage; however, the superconducting coil must increase the operating output voltage. Thus, the VS converter must be connected in a 6-series to provide the required operating output voltage. The output voltage of the VS converters is controlled continuously; however, reactive power is limited within a minimized value of the grid. In this study, the unit converter is compared with converters connected in a 6-series to determine a suitable sequence control method. The output voltage is the same in all cases, but the maximum reactive power is reduced from 100% to 73%. This sequence control method is verified through RTDS simulation.

• Journal of Biomedical Engineering Research
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• v.31 no.2
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• pp.114-122
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• 2010

This paper presents a method that registers a lymphoscintigraphy to the real image captured by a CMOS camera, which helps surgeons to easily and precisely detect sentinel lymph nodes for sentinel lymph node biopsy in breast cancer patients. The proposed method consists of two steps: pre-matching and image registration. In the first step, we localize fiducial markers in a lymphoscintigraphy and a real image of a four quadrant bar phantom by using image processing techniques, and then determines perspective transformation parameters by matching with the corresponding marker points. In the second step, we register a lymphoscintigraphy to a real images of patients by using the perspective transformation of pre-matching. To examine the accuracy of the proposed method, we conducted an experiment with a chest mock-up with radioactive markers. As a result, the euclidean distance between corresponding markers was less than 3mm. In conclusion, the present method can be used to accurately align lymphoscintigraphy and real images of patients without attached markers to patients, and then provide useful anatomical information on sentinel lymph node biopsy.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.717-722
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• 2007

Most of DC 1500V electric railway substations have adopted diode rectifiers to supply stable DC power. However, the diode rectifiers operate in the first quadrant of the voltage-current plane and thus need regenerative inverters which transfer the surplus regenerative power caused by regenerative braking of electric train sets into the grid. In order to select the proper capacity and installation position of regenerative inverter, it needs to investigate the consumed and regenerative energy of the electric traction substations in advance. This paper presents an analysis of regenerative energy in two substations operating in Seoul Seolleung and Kwangju Yangdong substations. DC line voltage and feeder currents are measured for a day to calculate consumed and regenerative power far four feeders. We calculated an amount of regenerative energy consumed in other feeders and estimated the cost reduction in energy consumption due to the reuse of regenerative energy

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.127-137
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• 2020

This study is aimed to point out the direction for more reasonable and effective application of future digital technology in the exhibition. It's also to improve the satisfaction of visitors' overall experience through inspecting the special exhibition using digital technology in the national central museum in 2019. The relationship of visitors' expectations, experience and satisfaction are analyzed through literature investigation. Hence, four dimensions of digital experience were summarized on this basis, the content of the questionnaire was set through this research. The satisfaction of visitors to the digital technology experience was evaluated and the key contents needing to be improved were found through Importance-Performance Analysis (IPA). According to the IPA analysis, the content located in quadrant IV is analyzed emphatically, and improvement suggestions are put forward from macro-level, micro-level and viewer's inner levels. The results can be used as a reference for improving the feasibility of the current problem. In order to ensure the forward-looking and timeliness of this field, continuous research will be conducted according to the changes and developments.