• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2000.01a
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• pp.35-37
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• 2000

• Korean Journal of Head & Neck Oncology
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• v.22 no.2
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• pp.142-146
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• 2006

Background and Objectives : This study reports our clinicopathological experiences of major salivary gland tumors. Materials and Methods : This study included 302 patients with major salivary gland tumors who had got the diagnosis from January 1995 through December 2004. Medical records were reviewed retrospectively. Results : We found 244 benign and 58 malignant major salivary gland tumors. Among 267 parotid tumors, the most common benign parotid tumor was pleomorphic adenoma. Mucoepidermoid carcinoma, adenoid cystic carcinoma, and acinic cell carcinoma were three most common parotid malignancies. Among 33 submandibular gland tumors, 20 cases were benign and 13 were malignant. There were one benign and one malignant sublingual gland tumors. The duration of symptom of submandibular gland tumors was longer than that of parotid tumors. Most patients presented with asymptomatic mass. Seventy-one percent of salivary gland malignancies underwent postoperative radiation therapy. Five-year disease free survival rate of parotid malignant tumors seemed to be higher than that of submandibular one, although there was no statistical significance. Conclusion : Malignancy rate of each salivary gland followed old axiom that it is inversely related with the size of gland. Submandibular gland tumor tends to be delayed to reach diagnosis. Clinicians must be alert about this finding because submandibular gland tumors are known to have poorer prognosis than parotid tumors.

• Physical Therapy Korea
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• v.26 no.2
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• pp.61-68
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• 2019

Background: Forward head posture (FHP) is a postural alignment of the cervical vertebrae that leads to increased gravitational load on cervical segmental motions. The overhead arm lift test assesses the ability to actively dissociate and control low cervical flexion and move the shoulders through overhead flexion. Objects: The purpose of this study was to explore muscle activities in the upper trapezius (UT), serratus anterior (SA), sternocleidomastoid (SCM), and lower trapezius (LT) alongside changes in head position during the overhead arm lift test in individuals with FHP. Methods: Fifteen subjects with forward head posture and fifteen subjects with normal subjcects were enrolled in this study. The patients performed the overhead arm lift test, and muscle activities of the UT, SCM, SA, and LT were measured using surface electromyography and by evaluating changes in head position. Independent t-tests were used to detect significant differences between the two groups and Cohen's d was calculated to measure the size of the mean difference between the groups. Results: The FHP group demonstrated significantly increased muscle activity of the UT ($32.46{\pm}7.64$), SCM ($12.79{\pm}4.01$), and LT ($45.65{\pm}10.52$) and significantly decreased activity in the SA ($26.65{\pm}6.15$) than the normal group. The change in head position was significantly higher in the FHP group ($6.66{\pm}2.08$) than the normal group. Effect sizes for all parameters assessed were large between the two groups. Conclusion: The subjects with excessive FHP displayed were unable to fix their heads in position during the overhead arm lift test. The overhead arm lift test can thus be used in clinical settings to confirm control of the neck in these subjects.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3292-3294
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• 1999

In this paper, electrostatic scanner mirror for optical pick-up head is designed and fabricated. The mirror size is $20{\mu}m{\times}2400{\mu}m{\times}2400{\mu}m$ and torsional beam size is $10{\mu}m{\times}20{\mu}m{\times}500{\mu}m$. Static deflection angle is calculated ${\pm}0.4$ degrees when the maximum driving voltage is 20 V. Silicon mirror was fabricated using KOH etching and deep RIE. For passivation of the patterned mirror from KOH solution, parylene thin film was used and its usefulness has been verified. Driving electrode was fabricated using UV LIGA process. Mirror and electrode were bonded.

• Clinics in Shoulder and Elbow
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• v.22 no.3
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• pp.119-120
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• 2019

• Korean Journal of Head & Neck Oncology
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• v.22 no.1
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• pp.36-39
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• 2006

The Neurofibroma is a benign neoplasm originating from neural tissue such as Schwann cell, fibroblast and peripheral fibroblast, which rarely converts to malignancy. About 25-45% of neurofibroma are located in head and neck, and the most common sites are lateral cervical region and mouth. Because of its high vascularity and invasion to the adjacent organs, surgical resection may be confronted and limited, moreover large neurofibroma can cause large defect that needs various kinds of flap. The factors related to clinically suspected malignancy are painlessness, abrupt increase in size, firm fixation, and central ulceration, although the malignancy rate of neurofibroma is low. The complete resection was failed several times at local clinic, the patient was transferred to our hospital. We have successfully removed the retroauricular neurofibroma using transposition flap & free skin graft on its large defects.

• Korean Journal of Head & Neck Oncology
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• v.33 no.2
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• pp.49-53
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• 2017

Foregut cystic developmental malformations are rare developmental anomalies. It is important to diagnose the diseases and manage them properly because these cysts may generate feeding or respiratory difficulties depending on the size and location of the lesions. A newborn was referred for a congenital cervical swelling to our clinic on the second day of his life. Neck SONO and MRI showed an about 6cm sized cystic mass at left submandibular area. Aspirations and sclerotherapies were done repeatedly due to recurred cystic mass. Under the suspicious of cystic hygroma, the mass and submandibular gland were excised. Histologically, it was a benign cyst including gastrointestinal and bronchogenic mucosa and pancreatic tissue. Foregut cyst was suggested for the final diagnosis and the patient was discharged at 9 days after the operation without a complication. He has visited our out-patient department. Although several image studies have been introduced to find out foregut cyst, it is difficult to go through differential diagnosis because of similarity of other benign tumor. Further studies for early diagnosis of cervical foregut cyst are needed for preventing possible related problems.

• The Korean Journal of Emergency Medical Services
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• v.15 no.2
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• pp.55-66
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• 2011

Purpose: The purpose of this study was to develop a scenario and evaluate the performance of paramedic students in head trauma simulation education. Method: This study selected a refined head trauma scenario that was developed by graduate students during class from september to November, 2010. Evaluation on implementation of head trauma simulation was conducted on seventeen paramedic students divided into four groups during November, 2010. Results: 1. The head trauma scenario was developed according to the patient assessment for approximately 10 minutes. It contained scene size-up, initial assessment and intervention, rapid trauma assessment and intervention, and decision of transfer. 2. The average time turned out to be 9 min and 36 sec after simulation learning. Total mean score in simulation performance was 2.20, the highest score was 2.44 in initial assessment and intervention, and the lowest score was 1.5 in decision of transfer. 3. Confidence mean was high with the score of 1.0. Conclusion: The finding of this study demonstrate that the simulation education can improve problem-solving ability and critical thinking, and increase the confidence in prehospital emergency care; therefore, simulation may be the new effective paramedic education strategy and simulation learning is needed for further development of various scenarios.

• ETRI Journal
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• v.18 no.3
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• pp.171-179
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• 1996

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of $0.15{\mu}m$ gate length with $1.35{\mu}m-wide$ head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at $V_{ds}=2V andI_{ds}=17mA$ was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.1-7
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• 1998

The near field radiated from the monopole antenna of the cellular phone was calculated by using the modified finite difference time domain algorithm derived from the integral form of Maxwell's equations. Substituting the near field value into the differential form of Maxwell's equations, SAR's distribution in the human head was obtained. The human head was simulated by a model of 800,000 block cells with dielectric constant and conductivity. The cell size was taken to be 0.5 cm. the transmitted power of the cellular phone was assumed to be 0.6 watts at the frequency of 833 MHz. The distance between the head and the cellular phone was 2.0 cm, the maximum SAR induced in the human head was about 1.5 W/kg and was below the IEEE's upper safety limit of 1.6 W/kg.