Reconstruction of a large chest wall defect using bilateral pectoralis major myocutaneous flaps and V-Y rotation advancement flaps: a case report

조강연,윤진명,기세휘 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.1

Bilateral pectoralis major myocutaneous (PMMC) flaps are commonly used to reconstruct large chest wall defects. We report a case of large chest wall defect reconstruction using bilateral PMMC flaps augmented with axillary V-Y advancement rotation flaps for additional flap advancement. A 74-year-old male patient was operated on for recurrent glottic squamous cell carcinoma. Excision of the tumor resulted in a 10×10 cm defect in the anterior chest wall. Bilateral PMMC flaps were raised to cover the chest wall defect. For further flap advancement, V-Y rotation advancement flaps from both axillae were added to allow complete closure. All flaps survived completely, and postoperative shoulder abduction was not limited (100° on the right side and 92° on the left). Age-related skin redundancy in the axillae enabled the use of V-Y rotation advancement flaps without limitation of shoulder motion. Bilateral PMMC advancement flaps and the additional use of V-Y rotation advancement flaps from both axillae may be a useful reconstructive option for very large chest wall defects in older patients.

Analysis of the Chest Wall Reconstruction Methods after Malignant Tumor Resection

조강연,기세휘 대한성형외과학회 2023 Archives of Plastic Surgery Vol.50 No.1

Background The chest wall defects can be caused by various reasons. In the case of malignant tumor resection of the chest wall, it is essential to reconstruct the chest wall to cover the vital tissue and restore the pulmonary function with prevention of paradoxical motion. With our experience, we analyzed and evaluated the results and complications of the chest wall reconstructions followed by malignant tumor resection. Methods From 2013 to 2022, we reviewed a medical record of patients who received chest reconstruction due to chest wall malignant tumor resection. The following data were retrieved: patients’ demographic data, tumor type, type of operation, method of chest wall reconstruction of the soft and skeletal tissue and complications. Results There were seven males and six female patients. The causes of reconstruction were 12 primary tumors and one metastatic carcinoma. The pathological types were seven sarcomas, three invasive breast carcinoma, and three squamous cell carcinomas. The skeletal reconstruction was performed in six patients. The series of the flap were eight pedicled latissimus dorsi (LD) myocutaneous flaps, two pectoralis major myocutaneous flap, two vertical rectus abdominismyocutaneous free flap, and one LD free flap. Among all the cases, only one staged reconstruction and successful reconstruction without flail chest. Most of the complications were atelectasis. Conclusion In the case of accompanying multiple ribs and sternal defect, skeletal reconstruction would need skeletal reconstruction to prevent paradoxical chest wall motion. The flap for soft tissue defect be selected according to defect size and location of chest wall. With our experience, we recommend the reconstruction algorithm for chest wall defect due to malignant tumor resection.

태양광발전 저압연계시 인버터 출력단 전압상승에 대한 연구

조강연,어익수 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.11

As environmental issues have been taken seriously, the number of solar power generation facilities has rapidly increased in Korea. The voltage at the output stage of an inverter increases in a system that connects a small-capacity photovoltaic power generation to low-voltage power distribution. This degrades the quality of the low-voltage distribution system and adversely affects the load facility. In this study, a solution was obtained to increase the voltage at the output stage of the solar inverter according to the connection of the low-voltage distribution system. The voltage can be controlled by using reactive power factor control inverters. If the secondary tap is adjusted, the voltage can be adjusted to about 15 V, but there is a problem in that the tap is not adjusted unless the KEPCO distribution regulation voltage is out of the range of 220±13V. If the number of inverters is limited, the inverter can be started within the inverter overvoltage range. If it is connected to three phases, the voltage is distributed. The results indicated that power factor control and active voltage control inverters were easy to apply in the field. 환경문제가 세계적으로 심각하게 다뤄지면서 우리나라도 태양광발전 설비가 급속도로 증가하였다. 특히 소용량 태양광발전을 저압배전으로 연계하는 계통에서 인버터 출력단의 전압상승으로 인하여 저압배전계통 품질저하 및 부하설비에 악영향을 주고 있다. 또한 과전압에 의한 인버터 가동중지로 인하여 발전소의 경제적 손실을 줄 수 있다. 본 논문에서는 저압배전계통 연계에 따른 태양광 인버터 출력단 전압 상승 해결방안을 연구 하였다. 첫째, 역률제어 및 능동전압제어 인버터를 사용하여 무효전력을 제어하면 출력단 전압이 230.91V에서 208.99V로 단자전압 비율이 약 10%가 내려갔다. 둘째, 배전전압용 변압기 2차 Tap을 조정하면 약 15V의 전압조정이 가능하지만, 한전배전규정전압이 220±13V의 범위가 벗어나지 않는 한 Tap을 조정해 주지 않는 문제점이 있다. 셋째, 인버터의 댓 수를 제한하면 인버터 과전압 범위 안에서 인버터를 기동할 수 있다. 넷째, 단상이 아닌 삼상으로 연계하면 전압이 분배되어 전압상승을 방지 할 수 있다. 4가지 중 현장 적용이 용이한 것은 역률제어 및 능동전압제어 인버터를 사용하는 것임을 확인하였다.

TFT-LCD 구동회로에서의 EMI 개선을 위한 Power/Ground Plane 모델링 및 실험적 검증

조강연(Kang-Yean Cho),나완수(Wan-Soo Nah),이재훈(Hae-Hoon Lee),이성규(Sung-Kyu Lee) 대한전기학회 2005 대한전기학회 학술대회 논문집 Vol.2005 No.11

전자식 과전류차단기를 이용한 전원자동차단 감전보호 개선연구

조강연(Kang-Yeon Cho),어익수(Ik-Soo Eo) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.11

현재 전기설비기술기준의 판단기준 내용이 한국전기설비규정(KEC : Korea Electro-technical Code, 이하 KEC)으로 제정되어 현장에 적용되고 있다. 판단기준의 저압전기설비 감전보호는 누전차단기의 설치 및 접지저항 값 위주였으나, KEC에서는 인체 허용접촉전압이 50 V 이하가 되도록 규정하고 있다. 만약 인체 허용접촉전압이 50 V를 초과할 경우에는 보호장치를 사용해 통전시간을 제한하여 감전보호를 해야 한다. 본 논문에서는 실제 현장의 과전류차단기를 이용한 전원자동차단에 의한 감전보호 가능여부를 용량별 10, 100, 300 kW로 구분하여 시뮬레이션 하였고, 그 결과 현장에 설치된 과전류차단기로는 KEC에 규정된 최대차단시간 5초 이내를 만족시키지 못하였다. 이에 대한 개선방안으로 동작특성이 조정 가능한 전자식 과전류차단기로 검토한 결과, 단 한시 전류(Isd)와 단 한시 트립 시간(Tsd) 정정을 10 kW(정격전류의 7배, 50 ms), 100 kW(정격전류의 5배, 50 ms), 300 kW(정격전류의 2배, 50 ms)로 할 경우 고장 전류에 대하여 KEC에 규정된 최대차단시간 5초 이내에 과전류차단기가 동작하여 전원자동차단에 의한 감전보호가 가능한 것을 확인하였다. The judgment criteria of the Korea Electro-technical Regulation have been incorporated into the Korea Electro-technical Code(KEC) and are currently being applied. Electric Shock Protection for low-voltage judgment criteria center on the installation of an earth leakage breaker and ground resistance value, but the KEC stipulates that the acceptable human body contact voltage limit should be 50 V, and that if body contact voltage exceeds 50 V, a Protective Device should be installed to limit the energization time. In this paper, the possibility of Electric Shock Protection by Power Cut-off using an Over-current Circuit Breaker in the field was simulated using capacities of 10, 100, or 300 kW. We found that the Over-current Circuit Breaker installed in the field did not satisfy the maximum trip time of ≤ 5 seconds stipulated in the KEC. Furthermore, a review of an electronic Over-current Circuit Breaker with adjustable operating characteristics revealed that setting short-time current(Isd) and short-time trip time(Tsd) settings to 10 kW(7 times the rated current, 50 ms), 100 kW(5 times the rated current, 50 ms), 300 kW(twice the rated current, 50 ms) resulted in Over-current Circuit Breaker operation within 5 seconds of the maximum cut-off time stipulated in the KEC for a fault current and confirmed the feasibility of Electric Shock Protection by Power Cut-off.

초고층 건축물의 수평진동 사용성 평가기준

조강표(Kangpyo Cho),홍성일(Sungil Hong),정승환(Seung-Hwan Jeong),조수연,Wonsul Kim 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Abstract should be in This paper presents review on human comfort criteria in major codes and standards for tall buildings. In general, human comfort criteria of tall buildings have been used by magnitude of wind-induced acceleration response. Two different indexes in determination of the magnitude have been used: the peak value which occurs during a period of time and the rms value averaged over this same period. These distinctive acceleration indexes are discussed in detail and each criterium was reviewed and compared. The distinctions arisen because of the different wave forms, or acceleration signatures were addressed. It is described that which index of acceleration should be adopted in establishment of Korean human comfort criteria. In addition, some arguments from a technical standpoint that favor the use of each index are presented.

진동대 실험을 통한 수평진동 체감도 평가

조강표,정승환,정명채,조수연 한국풍공학회 2007 한국풍공학회지 Vol.11 No.1

본 논문에서는 진동대 실험을 통한 수평진동에 대한 체감도를 평가하고자 한다. 먼저 국외선행연구를 조사하여, 실험의 적절한 방향을 모색하였다. 실험은 1차원 수평 진동대를 사용하고, 무빙룸은 우리가 생활하고 있는 공간과 유사하게 설계 및 제작하였다. 실험평가방법은 피험자를 40명 모집하여, 8명씩 5개조로 나누어 주파수 0.2Hz~1.2Hz 범위에서 가속도를 증가시켜 체감도에 대해 평가하였다. 수평진동 실험으로 얻어진 체감도 누적분포를 0~20%, 21~40%, 41~60%, 61~80%, 81~100%로 나누어 추세선을 그려서 성능평가곡선을 작성하였다. 또 국외 사용성 평가기준에 반영된 설문지를 바탕으로 실험에 적합한 설문지를 제작하여, 진동에 대한 피험자들의 느낌을 조사하였다. 실험결과를 주파수에 따른 지각임계가속도로 평가하였다. 그리고, 인간의 수평진동지각에 대해 감각적요소 즉 시각적, 청각적요소가 얼만큼 영향을 주는지 정량적으로 평가하였다. In this paper, threshold of motion perception for horizontal vibration was estimated by one-dimensional shaking table. After investigating preceding studies in foreign countries, a suitable course of experiments was organized. We used one-dimensional shaking table for horizontal vibration tests, and a vibration house made similar to a living space was made. Experimental results were recorded by increasing acceleration in the range of 0.2Hz through 1.2Hz of frequency after organized into five experimental groups, each of which was composed of eight persons. We obtained performance curves by dividing the distribution of perception from horizontal vibration tests into the range of 0~20%, 21~40%, 41~60%, 61~80%, 81~100% and then fitting curves. Also we made questionnaire based on human comfort criteria of foreign countries, and examined the feeling of subjects. From the results of horizontal vibration tests, it was found that acceleration of perception was low when frequency was high, and that visual and auditory senses affects the human perception for horizontal vibration.

고층 건축물의 수평진동에 대한 사용자의 지각임계가속도

조강표,신성우,정승환,조수연,Cho, Kang-Pyo,Shin, Sung-Woo,Jeong, Seung-Hwan,Cho, Soo-Youn 한국전산구조공학회 2007 한국전산구조공학회논문집 Vol.20 No.3

본 논문에서는 진동대를 이용하여 고층 건축물의 수평진동에 대한 지각임계가속도를 측정하였다. 바람에 의한 초고층 건축물의 과도한 진동은 거주자들에게 시각차와 현기증 같은 불쾌감을 줄 수 있다. 초고층 건축물 거주자들에게 쾌적한 환경을 제공하기 위해서는 가속도를 제한할 필요가 있다. 초고층 건축물은 1차 고유주기에 지배적이다 본 연구진은 1차 고유주기를 재연하기 위해 진동대를 사용하여 사인파진동에서 실험을 수행하였다. 실험은 진동하우스를 제작하고, 건장한 40명의 피험자를 대상으로 실시하였다 40명의 피험자를 8명씩 5개조로 나누고, 특정주파수범위$(0.2Hz{\sim}1.2Hz)$에서 가속도를 증가시키면서 수평진동에 대한 인지도를 측정하였다. 수평진동실험으로 피험자들의 진동에 대한 인지도를 누적분포표로 만들고, $0{\sim}20%,\;21{\sim}40%,\;41{\sim}60%,\;61{\sim}80%,\;81{\sim}100%$의 누적분포에 대해 추세선을 그려서 성능평가곡선을 작성하였다. In this paper, acceleration threshold of perception for the horizontal vibration of tall buildings was estimated. Excessive vibration of tall buildings by wind can give displeasure, such as giddiness and visual insecurity. To provide comfortable environment to residents of tall buildings, acceleration needs to be limited. For tall buildings the first mode of vibration is dominant. To reproduce the first mode of vibration, experiments were performed by generating sine waves by a shaking table. A nitration house was made and forty persons were employed for experiments. The forty persons were organized into five experimental groups, each of which was composed of eight persons, and the threshold of perception for horizontal vibration was measured by increasing acceleration in the range of 0.2Hz through 1.2Hz of frequency, Performance curves were obtained by dividing the distribution of perception for horizontal vibration into the range of $0{\sim}20%,\;21{\sim}40%,\;41{\sim}60%,\;61{\sim}80%\;and\;81{\sim}100%$ and by fitting curves.

정신지체 학생의 언어능력 향상 지도자료

신병수,조강연 국립특수교육원 1995 현장특수교육 Vol.2 No.4

친환경 섬유 소재 개발을 위한 최적 물성 예측 알고리즘에 관한 연구

임주희,양진호,조강연,노상도,손현식,정우창,심승범 대한산업공학회 2022 대한산업공학회지 Vol.48 No.6

Due to various environmental issues such as global warming, eco-friendly technology becomes more significant attention in manufacturing industries. In textile industry, a large amount of chemicals substances and energy can cause serious environmental pollution, so that it is necessary to develop and use eco-friendly fiber material to keep our environment clean. Extraction of optimal process conditions and prediction of the product quality before production starts are the critical steps to reduce the waste and defect rate in developing biodegradable eco-friendly materials. This paper proposes an AI-based algorithm that predicts the optimal process conditions and parameters of the spinning process based on manufacturing data. The developed algorithm is consisted of various machine learning models, and the performance of the model is verified by performance indicator evaluation of actual production processes.