• 전기전자학회논문지
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• 제24권1호
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• pp.216-224
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• 2020

본 논문은 계통 연계 기준인 Low Voltage Ride Through(LVRT) 및 High Voltage Ride Through(HVRT) 기능을 평가하기 위한 시험 장비의 임피던스 설계 방법을 제안한다. LVRT/HVRT 시험 장비는 계통 연계 규정에 명시되어 있는 계통 사고 전압을 일정시간 동안 발생시킬 수 있어야 하며 설계 사양에 맞게 사고전류의 크기를 제한해야 한다. 본 논문에서는 LVRT/HVRT 동작 시 탭 변환 단권변압기 시험 장비의 등가 모델을 기반으로 계통 연계 규정을 만족하기 위한 단권변압기의 임피던스를 설계한다. 제안하는 설계 방법을 이용하여 LVRT/HVRT 시험 시 요구되는 다양한 사고전압을 출력할 수 있는 시험장비의 설계를 위한 탭 간의 임피던스 설계 과정을 설명한다. 제안하는 설계 방법의 타당성을 검증하기 위하여, 10MVA급 LVRT/HVRT 시험 장비의 설계 과정을 설명하고 시뮬레이션을 통하여 확인하였다.

• 치위생과학회지
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• 제23권2호
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• pp.176-184
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• 2023

Background: Recently, a piezoelectric ultrasonic scaler based on a feedback control mechanism was introduced for pain relief. This study aimed to investigate the effects of a new ultrasonic scaler in reducing pain and discomfort in adults. Methods: A newly introduced ultrasonic scaler (Master 700^®) was used as the test device and a conventional ultrasonic scaler device (PIEZON^®) was used as the control device. Forty-one healthy adults visited the dental clinic for dental scaling but did not undergo scaling or periodontal treatment within 6 months. Intraoral examinations were performed before scaling and 3 months later; before scaling, both devices were randomly assigned on the left or right side of each dentition (split-mouth model) and scaling was performed by a registered dental hygienist. The levels of pain and discomfort during scaling were evaluated subjectively and objectively using the visual analog scale (VAS) and physiological monitoring of the heart rate (HR), respectively. Time was measured for each device. Results: All clinical indicators, except bleeding on probing, significantly improved with both devices. The treatment times were 7 minutes, 13 minutes (control) and 6 minutes, 59 minutes (test). VAS scores for pain were 4.89±2.12 (control) and 4.58±2.77 (test) points out of 10; for noise, these were 4.68±2.33 (control) and 4.55±2.55 (test), and for vibration, the values were 4.26±2.0 (control) and 4.18±2.48 (test). HR averages were 72.34±3.39 (control) and 75.97±9.78 (test) beats/min. No statistically significant differences were observed between the devices. Conclusion:The pain, discomfort levels, and scaling time of the new piezoelectric ultrasonic scaler did not differ from those of the conventional device. Further research and development are necessary for more prominent pain-relief effects of scaling devices.

• 한국방사선학회논문지
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• 제13권3호
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• pp.391-398
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• 2019

본 논문에서는 Telos Device를 이용한 검사 시 인가한 daN 힘의 차이와 무릎의 안정성에 관여하는 근육들의 개인차에 따른 전방십자인대의 동요 정도에 대해 연구하고자 한다. Telos Device를 이용한 Lachman Test로 검사하였으며, 오른쪽과 왼쪽을 각각 0, 15, 30 daN, 운동부하 후 30 daN의 힘으로 변화하며 검사하여 전방십자인대의 변화를 측정하였다. 근육량 측정은 CT(Computed Tomography)를 이용하였으며, 힘줄(tendon)을 피해 근육을 측정하기 위해 무릎뼈(patella) 상방 8 cm의 위치를 검사하였다. 전방십자인대(Anterior Cruciate Ligament)의 변화 정도는 Piview의 Caliper 기능을 이용하여 측정하였으며, 근육량은 CT 단면 영상을 Image J 프로그램을 이용하여 지방을 제외한 뼈와 근육의 면적을 측정하였다. 측정값들은 SPSS Ver. 18을 이용하여 결과 값을 얻었다. Telos Device 로 인가하는 힘의 변화에 따라 전방십자인대의 동요 정도를 측정한 결과 오른쪽과 왼쪽 모두 15 daN과 30 daN의 힘을 인가하였을 때 통계적으로 유의한 무릎 동요의 차가 발생하였으며(p<0.05), 30 daN과 운동부하 후 30 daN에서의 동요 정도는 유의한 차이를 보이지 않았다(p>0.05). 근육면적의 차이와 전방십자인대의 동요 정도와의 상관관계에서 15 daN의 압력에서 오른쪽 r=-0.45, 왼쪽 r=0.44로 음의 상관관계를 보였다(p<0.05). Telos Device에 인가하는 힘의 정도에 따라 전방십자인대의 동요는 커지는 것으로 분석되며, 또한 개인의 근육량의 차이에 따라 전방십자인대의 동요 정도에도 차이를 보이는 것으로 분석된다. 따라서 개인의 근육량의 차이에 따라 Telos Device에 인가되는 힘도 변화되어야 하는 것으로 사료된다.

• 전기학회논문지
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• 제63권12호
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• pp.1726-1731
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• 2014

This paper shows the developed new lightning arrester LCM (Leakage Current Measuring device) which is important element of GIS (Gas Insulated Switchgear) Preventive & Diagnostic system and verify its performance though strengthened test standards. The existing lightning arrester LCM was modified to solve measuring errors which happened frequently. At first, we explained the principle of measuring leakage current. Through analyzing some problems which the existing LCM have. we got some improvable items. For the performance verification of the improved LCM, we manufactured prototype LCM which is applied some improvable items such as improving LCM circuit, adding protection circuit, optimizing inner structure of LCM and changing ground design. After then we carried out the performance test. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria. Also, we confirmed the performance of the improved LCM installed & being operated at G Substation through the immunity test against the normal noise and open/close surge etc.

• 대한의용생체공학회:의공학회지
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• 제33권2호
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• pp.89-97
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• 2012

The purpose of this study is to develop the guideline of the physicochemical and mechanical properties evaluation for silicone gel filled breast implants. First of all, the use and development status for silicone gel filled breast implants were investigated, and then, standard and criteria about performance evaluation established by the international organizations such as ASTM, FDA guidance and ISO were examined. To evaluate the mechanical properties, data research and testing for breaking strength, elongation, tensile set, joint intensity, silicone gel cohesion, weight loss from heating, static rupture resistance, impact resistance test, fatigue test, and gel bleed were performed. On the other hand, to evaluate the physicochemical properties, volatile matter, extent of cross linking, heavy metals, and extractable were analyzed. In this study, results for general function, mechanical properties and physicochemical properties were examined and reviewed for the accordance with international standard, and objective and standardized guideline was provided.

• 대한안전경영과학회지
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• 제10권3호
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• pp.73-79
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• 2008

Display's life time is defined as the time of 50% luminance drop. It was used luminance and temperature as accelerated factor to accelerated lifetime at test. When it's working jule-heat is generated and device's temperature is growing as any temperature because OLED is self-luminance display device. So we decided temperature condition is 25, $70^{\circ}C$, and luminance condition is $60{\sim}300cd/m^2$ in test. It's assumed accelerated lifetime model by result of the test.

• 대한방사선기술학회지:방사선기술과학
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• 제31권2호
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• pp.123-127
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• 2008

목 적: 임상에서 인버터식 X선장치의 사용이 보편화됨에 따라 이에 대한 보다 정확하고 간편한 성능평가 방법이 요구되고 있다. 따라서 최근 국내에 소개되어 사용되고 있는 X-Ray Multi-Function Test Device (model : Xi (unfors)-prestige)를 이용한 성능평가의 유용성을 확인하고자 한다. 방 법: 인버터식 X선장치의 성능 평가시 접속형 측정장비로 널리 활용되고 있는 Dynalyzer III를 이용한 성능평가를 기준으로 하여 비접속형 측정장비인 X-Ray Multi-Function Test Device (model: Xi (unfors)-prestige)의 성능평가를 비교 분석하여 그 유용성을 검토하였다. 결 과: 두 측정기에 대한 X선 출력선량은 큰 차이 없이 측정되었으며 촬영조건 등의 변화에 따라서 접속형인 Dynalyzer III가 약간 증가된 값으로 측정되었으며 출력의 재현성은 두 측정기 모두 성능평가 합격 기준 0.05 이하인 0.002 이하로, 직선성은 합격기준인 0.1 이하로 평가되었다. 촬영조건의 정확도에서는 관전압은 1.8과 2, 관전류는 2.01과 2.3, 촬영시간은 T > 0.01 sec에서 ${\pm}10%$ 이하로 나타났다. 모두 성능평가 기준의 허용범위에 있는 것으로 나타났다. 결 론: X-Ray Multi-Function Test Device (model: Xi (unfors)-prestige) 측정기를 이용한 인버터식 X선장치의 X선 출력의 재현성, 직선성과 촬영조건의 정확도에 대한 성능평가의 유용성을 확인하였다.

• 한국유체기계학회 논문집
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• 제15권4호
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• pp.42-49
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• 2012

This study is performance estimation of wind augmentation device for BiWP(Building-integrated Wind Power) which recently attracts attention as a local power. various structures are installed on a rooftop of residential complex buildings. Changing a profile of these, we designed a configuration that is able to capture much air and increase exit velocity. To estimate wind augmented effect of this device, we compared numerical analysis results with wind tunnel test results. Results show that exit velocity is increased from 24% to 60% by wind augmented device on a rooftop of building.

• 항공우주시스템공학회지
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• 제14권2호
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• pp.12-19
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• 2020

In Korea, the regulation is MOLIT Notice 2018-290, Guidance for Approval of Synthetic Flight Trainer as Flight Simulator and Flight Training Device. The FAA (Federal Aviation Administration) categorizes FSTD (Flight Simulation Training Device) into FFS (Full Flight Simulator) and FTD (Flight Training Device), according to its level. Additional categories for regulation are airplane and helicopter, depending on the type of aircraft. In this study, the objective tests for the handling quality of the FAA and Korean regulations were compared and analyzed. In QPS (Qualification Performance Standard), related test titles, flight conditions, and tolerance limits were analyzed for the handling quality. Based on this study, recommendations on amendments to the regulation was presented.

• 대한안전경영과학회지
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• 제10권4호
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• pp.145-152
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• 2008

According to the Korea Agency for Technology and Standards under the Commerce Ministry, OLED device's lifetime is defined 50% drop of luminance. OLED device is self-emitting operating device, that means it becomes different color between pixels under using environment. That's reason of the different luminance drop ratio & chromaticity coordinates shift ratio with time. The problem is there is not recovered after luminance drop and color shift. We can recognize the difference of color as image sticking. First we studied when human recognize the difference of color and second we apply the method of OLED device's lifetime test that's able to check different color between pixels.