• 한국항공우주학회지
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• 제41권1호
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• pp.61-69
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• 2013

항공기 비행성 평가 과정에서는 수많은 평가의 반복이 필요하기 때문에 평가 시스템에 있어서 간결하고 명확한 응용 인터페이스가 중요하다. 본 비행성 평가 프로그램은 달라진 트림 조건의 사용자 환경과 함께 효율적인 비행성 평가 사용자 환경을 구현하였다. 그리고 14 항목으로 선별된 무인 고정익기의 비행성 평가 자동화 모듈을 모두 탑재한 종합평가 환경을 구성하였다. 이에 따라 비행제어시스템 개발은 물론 비행성이 고려된 항공기를 개발함에 있어서 검증 및 평가 과정에 소요되는 비용과 시간을 대폭 감소시키고 향후 확장성을 겸비한 유용한 시험 평가 검증 도구로 활용될 수 있을 것으로 사료된다.

• 반도체디스플레이기술학회지
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• 제6권4호
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• pp.69-73
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• 2007

The MIM(metal-insulator-metal) capacitors with the Al/PMMA/ITO/Glass structures were manufactured according to various PMMA concentration of 1, 2, 4, 6, 8 wt%. The lowest leakage current and the largest capacitance were found to be 2.3 pA and 1.2 nF, respectively, for the device with 2 wt% PMMA concentration. The measured capacitance of the devices was almost same values with the calculated one. The optimum film thickness was obtained at the value of 48 nm, showing that the capacitance and leakage current were 1.92 nF, 0.3 pA at 2 wt%, respectively. From this experiment, the PMMA gate insulator films can be applicable to the organic thin film transistors.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2052-2060
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• 2006

The wear of engine valve and seat insert is one of the most important factors which affect engine performance. Because of higher demands on performance and the increasing use of alternative fuel, engine valve and seat insert are challenged with greater wear problems than in the past. In order to solve the above problems, a simulator was developed to be able to generate and control high temperatures and various speeds during motion. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. This work focuses on the different degrees of wear at three different singular test speeds (10 Hz, 25 Hz & multi-Hz). For this study, the temperature of the outer surface of the seat insert was controlled at 350$^{\circ}C$, and the test load was 1960 N. The test cycle number was $6.0{\times}10^6$. The mean ($\pm$standard error) wear depth of the valve at 10 Hz and 25 Hz was 45.1 ($\pm$3.7)$\mu$m and 81.7 ($\pm$2.5)$\mu$m, respectively. The mean wear depth of the seat insert at 10 Hz and 25 Hz was 52.7 ($\pm$3.9)$\mu$m and 91.2 ($\pm$2.7)$\mu$m, respectively. In the case of multi-Hz it was 70.7 ($\pm$2.4)$\mu$m and 77.4 ($\pm$3.8)$\mu$m, respectively. It was found that higher speed (25 Hz) cause a greater degree of wear than lower speed (10 Hz) under identical test condition (temperature, valve displacement, cycle number and test load). In the wear mechanisms of valves, adhesive wear, shear strain and abrasive wear could be observed. Also, in the wear mechanisms of seat inserts, adhesive wear, surface fatigue wear and abrasive wear could be observed.

• Journal of Trauma and Injury
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• 제28권3호
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• pp.98-103
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• 2015

Purpose: To compare injury sustained and severity of child occupant according to the types of safety restraint systems in motor vehicle crashes. Methods: This was a retrospective observational study. The study subjects were child occupants under the age of 8 years who visited a local emergency center following a motor vehicle crash from 2010 to 2014. According to safety restraint: child restraint systems (CRS), belted, and unbelted, we compared injuries sustained and injury severity using the maximal Abbreviated Injury Scale (MAIS) and Injury Severity Score (ISS), and analyzed the characteristics of severe injuries (AIS2+). Results: Among 241 subjects, 9.1% were restrained in CRS, 14.5% were only belted, and 76.3% was unbelted at the time of the crashes. Fourteen had severe injuries (AIS2+), all of whom didn't be restrained by CRS. Injuries in face and neck were the highest in unbelted group, and MAIS and ISS were the lowest in CRS group. Conclusion: Among safety restraint systems for child occupant in motor vehicle crashes, the CRS have the preventive effect of face and neck injuries, and are the most effective safety restraint systems.

• 대한산업공학회지
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• 제41권4호
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• pp.352-358
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• 2015

It is important to guarantee the safety of vehicle to minimize the damage to the driver in case of the accidents. In order to inspect and later enhance the safety of vehicle, the owner of the vehicle usually have a vehicle safety inspection. The Korea Transportation Safety Authority (KOTSA) issues the Comprehensive Performance Inspection Certificate after vehicle inspection. The certificate only specify the legal inspection criteria for safety and measured values of the safety parameters, however, as ordinary driver in lack of expert knowledge about the vehicle is difficult to understand the contents of the Certificate. Thus, in this paper, the authors try to give the information about the inspection results in easier way to understand. This information not only guarantees the owner of the vehicle to better understand the inspection results, but it also gives the opportunity to the driver to deal with the specific problem listed in the results. The methods in this paper are to transform the vehicle inspection data into the non parametric distribution to easily represent the values to the index later on. Also, example indexes are presented to the actually inspected vehicle based on the reference distribution to show the better assessment of the developed method.

• 마이크로전자및패키징학회지
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• 제12권1호
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• pp.21-26
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• 2005

The field effect transistors (FETs) were fabricated ell $Y_2O_3/Si(100)$ substrates by the conventional memory processes and sol-gel process using $(Bi,La)Ti_3O_{12}(BLT)$ ferroelectric gate materials. The remnant polarization ($2Pr = Pr^+-Pr^-$) int Pt/BLT/Pt/Si capacitors increased from $22 {\mu}C/cm^2$ to $30{\mu}C/ cm^2$ at 5V as the annealing temperature increased from $700^{\circ}C$ to $750^{\circ}C$. There was no drastic degradation in the polarization values after applying the retention read pulse for $10^{5.5}$ seconds. The capacitance-voltage data of $Pt/BLT/Y_2O_3/Si$ capacitors at 5V input voltage showed that the memory window voltage decreased from 1.4V to 0.6V as the annealing temperature increased from $700^{\circ}C$ to $750^{\circ}C$. The leakage current of the $Pt/BLT/Y_2O_3/Si$ capacitors annealed at $750^{\circ}C$ was about $510^{-8}A/cm^2$ at 5V. From the drain currents versus gate voltages ($V_G$) for $Pt/BLT/Y_2O_3/Si(100)$ FET devices, the memory window voltages increased from 0.3V to 0.8V with increasing tile $V_G$ from 3V to 5V.

• 농업과학연구
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• 제46권4호
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• pp.723-735
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• 2019

The power-train is the most important component of an agricultural tractor. In this study, the strength of the driving gear transmission of an 82 kW-class tractor was analyzed using equivalent torque during plow tillage. The load measurement system consisted of an engine revolution speed sensor, torque-meters, revolution speed sensors for four axles, and pressure sensors for two hydraulic pumps. The load data were measured during plow tillage for four speed stages: F2 (2.78 km/h), F5 (5.35 km/h), F7 (7.98 km/h), and F8 (9.75 km/h). Aspects of the gear-strength such as bending stress, contact stress, and safety factors were analyzed under two torque conditions: the equivalent torque at the highest plow load for the F8 speed stage and the maximum engine torque. The simulation results using KISSsoft showed that the maximum engine torque conditions had a lower safety factor than did the highest equivalent torque condition. The bending safety factors were > 1 at all gear stages, indicating that gear breakage did not occur under actual measured operating conditions, nor under the maximum torque conditions. However, the equivalent torque condition in the contact stress safety factor was > 1, and the maximum torque condition was < 1 at the first gear pair. The method of analysis using the equivalent torque showed lower stress and higher safety factor than did the method using maximum torque. Therefore, when designing a tractor by applying actual working torque, equivalent torque method would support more reliable product development.

• 한국융합학회논문지
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• 제9권6호
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• pp.209-215
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• 2018

대학 교양수학은 이공계열에서 필수 과목으로 개설하고 있으나 성취도가 낮은 학생들은 학습에 어려움을 느끼고 있어 대안으로 자기 주도와 학습자 중심으로 효과성이 높은 교수법으로 잘 알려진 플립러닝이 제시되고 있다. 그러나 이 교수법에서도 몇 가지 문제점들이 지적되고 있어 플립러닝에 대한 대안적 방법으로 PBL을 플립러닝에 적용한 플립 PBL 수업을 교양수학 과목에 적용하여 기존 플립러닝 수업의 문제점을 보완하고 수학에 대한 흥미를 높일 수 있는지의 효과성을 알아보고자 한다. 본 연구에서는 플립 PBL 수업을 적용한 실험집단과 기존 플립러닝 수업을 적용한 통제집단의 비교연구에서의 교육적 효과성을 알아본 결과 첫째, 지필고사 결과에서는 실험집단이 통제집단보다 평균이 22점 이상 높게 나타나 학업성취도 향상에 효과가 있는 것으로 나타났고 둘째, 성찰저널 분석에서는 통제집단과 대조적으로 실험집단에서 수학의 흥미도 향상에 대한 긍정적인 내용이 많아 흥미도 변화에도 긍정적 효과가 나타나 이교수법이 기존의 플립러닝을 보완할 수 있는 교수법으로 확대 적용되기를 기대한다.

• 비파괴검사학회지
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• 제33권2호
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• pp.187-192
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• 2013

크랙 계면에서의 접촉 열저항에 의해 만들어지는 온도 강하 특성을 적외선을 이용하여 측정함으로써 피로균열을 검사하였다. 크랙과 같은 불연속면을 지나는 열 유동은 연속체에서와는 달리 접촉경계면에서 급격한 온도구배를 나타내는데 이 변화를 표면에서의 적외선 방사량으로 측정하여 피로균열의 위치를 탐지하였다. 표준 피로균열 시편의 중앙부에 노치를 생성한 후 저주기 피로균열을 노치 끝단으로부터 발생시킨 다음, 이 시편의 한쪽 끝단에 할로겐램프를 이용하여 일정한 열을 가함으로서 시편의 길이 방향으로 열 유동이 일어나도록 하면서 시편의 표면온도 분포를 적외선 실험장치로 계측하였다. 열 유동이 크랙을 지나면서 온도구배가 크게 변화하는 것을 적외선 열화상 이미지로부터 알 수 있었으며 균열 면에서의 적외선 온도 데이터로부터 크랙의 위치와 크기를 평가할 수 있음을 실험적으로 확인하였다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.221-225
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• 2003

The MFIS-FET(Field Effect Transistor) devices using $BLT/Y_2O_3$ buffer layer on p-Si(100) substrates were fabricated by the Sol-Gel method and conventional memory processes. The crystal structure, morphologies and electrical properties of prepared devices were investigated by using various measuring techniques. From the C-V(capacitance-voltage) data at 5V, the memory window voltage of the $Pt/BLT/Y_2O_3/si$ structure decreased from 1.4V to 0.6V with increasing the annealing temperature from $700^{\circ}C\;to\;750^{\circ}C$. The drain current (Ic) as a function of gate voltages $(V_G)$ for the $MFIS(Pt/BLT/Y_2O_3/Si(100))-FET$ devices at gate voltages $(V_G)$ of 3V, 4V and 5V, the memory window voltages increased from 0.3V to 0.8V as $V_G$ increased from 3V to 5V.