• 한국환경교육학회지:환경교육
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• 제22권3호
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• pp.63-71
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• 2009

The aim of this study is to provide the basic data on misconception correction through the investigation of perception extent for 'environmental pollution' concepts in the elementary school students. For this, 18 investigation questions for concepts were created. And then a questionnaire was inputted for 446 elementary school students. The rate of average wrong answer for total questions was 34.9%. The eight questions were appeared as rate of wrong answers over average, suggesting that the misconception extent for 'environmental pollution' was still high. The extent of concepts for total questions between living environments of the study subjects did not show any significant differences. However, the urban students had significantly higher rate of wrong answers than rural students in the three questions, indicating that it is necessary to develop various teaching-learning materials on 'environmental pollution'. Therefore, the teachers have to study the various ways to induce the cognition conflicts through the application of proper teaching-learning for correction of 'environmental pollution' concepts.

• Journal of Chest Surgery
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• 제18권4호
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• pp.598-604
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• 1985

One hundred consecutive patients with the Tetralogy of Fallot underwent total correction at National Medical Center during the period 1977 to 1984, Oct. During this study period, we adopted more active policy towards reconstruction of right ventricular outflow tract across pulmonary valve. The mortality was 48% for patients less than 15 kg and 19% in patients above 15kg. Initially Bretschneider`s solution was used as cardioplegia, which was replaced by St. Thomas` solution since 1983, Jan. After then overall mortality dropped to 9% compared to 45% of initial learning period. Heart block occurred In 11 patients, 10 of whom died of combined low cardiac output syndrome. Pure low cardiac output syndrome was noted in 18 patients, most of whom responded to medical measures well except 4 patients. Recently sepsis of Serratia marcescence, which occurred explosively during several months to open heart surgery patients, attacked 3 tetralogy patients resulting in 2 hospital deaths. Our experience has shown that body weight, choice of cardioplegia and accumulation of experience as well as advance of operative and postoperative techniques are still important factors affecting survival rate at initial learning period.

• Archives of Plastic Surgery
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• 제36권6호
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• pp.743-749
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• 2009

Purpose: Many researches about various surgical method for blepharoptosis have already been introduced. But researches for complications after blepharoptosis correction is relatively insufficient. So, this study was performed to recognize common complications that arised depending on the severity of blepharoptosis, levator function and surgical method. Methods: 250 patients who have underwent surgical treatment for blepharoptosis from 1987 to 2006 were employed in this study. Patients were categorized by severity of blepharoptosis, levator function and surgical method that has been used. Complications after blepharoptosis correction were analyzed. Result: Total of 64 patients had occurred complications, the specifics are as following; undercorrection 22, asymmetry 13, overcorrection 12, lagophthalmos 4, abnormal eyelid contour 4, exposure keratitis 3, ectropion 2, inclusion cyst 2, infection 1 and conjunctival prolapse 1. Among above patients, 3 patients had two kinds of complications. 21 patients was underwent secondary surgery due to complication. Conclusion: Evaluating the outcomes of the secondary surgery, the early correction was better than the late correction. The most of the complications were recovered through conservative and surgical treatments. The most of the complications (47 patients) were undercorrection, asymmetry, overcorrection and took 73.4% of the total complications. The more severe the blepharoptosis and the more poor the levator function, the rate of complications were higher. According to the operation methods, most complications were occurred in levator operation, frontalis transfer and OOM flap.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.976-979
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• 2002

A new controller for switching audio power amplifier with digital PWM input is proposed- Bi-directional Saw-tooth Error Correction (BSEC). This control method for high quality switching amplifier is based on a pulsed edge correction approach using PWM audio signal input as a reference of power switching digital to analog converter. The proposed controller has excellent features such as wide error correction range and no limitation on the modulation index. The controller is implemented in the half-bridge class D amplifier and the performance is verified through hardware experiments. It delivers 100W into 4${\Omega}$ load with less than 0.2% of total harmonic distortion (THD) all over operating range and an maximum efficiency of 82%.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.73-80
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• 2000

The distance correction term -logA0 of the local magnitude scale was estimated for earthquakes in southern Korea using linear least-squares inversion and interpolation scheme. Total 1054 short-period velocity seismograms from 107 local events recorded at hypocentral distances ranging from 10 to 480 km were used in this study. Simulated Wood-Anderson amplitudes were obtained from velocity seismograms with use of revised Wood-Anderson instrument response with static magnification 2080, damping factor 0.7, and natural period 0.8 sec. The estimated distance correction term for southern Korea is found to be -logA0=1.137 log(r/17) + 0.001159(r-17) + 20, where r is hypocentral distance in kilometers. The attenuation rate of this distance correction term falls between those of southern California and eastern North America.

• Journal of Chest Surgery
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• 제28권11호
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• pp.1045-1048
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• 1995

Pulmonary atresia with VSD is uncommon congenital anomaly with high mortality in neonatal period.Recently we experienced surgical correction of pulmonary atresia with VSD. The case was 2 month old male patient diagnosed as pulmonary atresia with VSD and PDA. Atretic pulmonary artery segment from Rt ventricular infundibulum to pulmonary artery was lcm in length. The pulmonary trunk tapered toward Right ventricular infundibulum and resulted in blind pouch with diameter of lmm. The left pulmonary artery was stenosed at just proximal and distal part to which PDA was connected. Total correction was undertaken which consisted of PDA ligation, dacron patch closure of VSD, establishment of continuity between right ventricle and pulmonary artery with autogenous pericardium. Postoperative systolic fight ventricular pressure and left ventricular pressure ratio was 0.7. In patient with pulmonary atresia with VSD it is advisable to perform a corrective operation, whenever the size and anatomy of pulmonary artery are acceptable for it.

• 전력전자학회논문지
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• 제4권1호
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• pp.105-110
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• 1999

이 논문은 역률제어회로를 갖는 인버터 구동 에어컨에 관해 설명한다. 정류기에 역률제어회로를 적용함에 의해서 전원선으로의 고조파 삽입을 줄일 수 있고, 효율을 향상시킬 수 있으며, 기존의 인버터와 비교해서 전체 시스템 가격을 낮출 수 있다. 또한, 역률제어회로의 출력전압을 안정화함에 의해서 시스템 성능을 향상시킨다. 본 논문에서는 역률제어회로의 자세한 설계절차를 제시하고, 역률제어회로의 여러 가지 장점을 시뮬레이션과 실험을 통해서 확인하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.29-36
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• 2004

The paper describes recent experimental results on the development of Digital Magnetic Compass (DMC), which can provide smart automatic correction functions to the magnetic interferences. The design methodology of magnetic sensing circuit with ring-core fluxgate sensor is represented. The performance results of the sensing circuits are discussed with error analysis by polynomial regressions. As test results, the sensing circuit filtered only the second harmonic signal that is proportional to the direction of earth's magnetic field, and it leads to the obtainment of bearing information. In addition, the total residual errors of DMC can be analyzed by the adoption of polynomial regressions. It shown that the possibility of high precise DMC, in the future.

• ETRI Journal
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• 제29권1호
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• pp.27-35
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• 2007

Energy savings in orthogonal frequency division multiplexing (OFDM) systems is an active research area. In order to achieve a solution, we propose a new cooperative relaying scheme operated on a per subcarrier basis. This scheme improves the bit error rate (BER) performance of the conventional signal-to-noise ratio (SNR)-based selection relaying scheme by substituting SNR with symbol error probability (SEP) to evaluate the received signal quality at the relay more reliably. Since the cooperative relaying provides spatial diversity gain for each subcarrier, thus statistically enhancing the reliability of subcarriers at the destination, the total number of lost subcarriers due to deep fading is reduced. In other words, cooperative relaying can alleviate error symbols in a codeword so that the error correction capability of forward error correction codes can be fully exploited to improve the BER performance (or save transmission energy at a target BER). Monte-Carlo simulations validate the proposed approach.

• Journal of Chest Surgery
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• 제39권1호
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• pp.12-17
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• 2006

배경: 초 저체온 하 순환 정지는 총 폐정맥 환류 이상을 수술하는데 있어 중요한 보조 수단이다. 그러나 초 저체온 하 순환 정지 하에 심장 수술을 하는 것은 순환 정지 후 신경계 이상의 위험을 동반하고 있다. 이에 완전 순환 정지 없이 총 폐정맥 환류 이상을 수술하여 그 결과를 평가하고자 한다. 대상 및 방법: 2000년 4월에서 2004년 10월까지 10명의 환자의 의무 기록을 후향적으로 분석하였다. 결과: 해부학적 연결 이상의 위치는 심장 상부형이 7예,심장형이 1예, 심장 하부형이 2예였다. 평균 심폐기 가동 시간과 대동맥 차단 시간은 각각 116.8 $\pm$40.7분, 69.5$\pm$24.1분이었다. 수술로 인한 사망 예는 없었고, 합병증은 술 후 폐정맥 협착이 1예, 폐렴, 기흉, 창상 감염, 횡격막 마비가 각각 1예씩 있었다. 평균 16.6개월의 추적 관찰 기간동안 페동맥 협착이 없었던 모든 환아는 NYHA class I으로 지내고 있다. 결론: 총 폐정맥 환류 이상을 완전 순환 정지 없이 수술하여 아주 만족할 만한 결과를 얻을 수 있었다.