속도 벡터에 따른 타원형 충돌범위를 적용한 Anytime DRRT 기반 실시간 동적 장애물 충돌회피 알고리즘

박찬휘,노기문,박지훈,송우석,권준수,이대우 한국항공우주학회 2023 韓國航空宇宙學會誌 Vol.51 No.12

Anytime DRRT(Directed Rapidly-exploring Random Tree) 알고리즘은 RRT 알고리즘에서 수렴성을 보완하고, 경로 생성 시간을 단축하며 위치 정보 갱신 주기 동안 계산을 반복하여 그중 가장 짧은 경로를 선택하여 최적성을 보완하는 충돌회피 경로 생성 알고리즘이다. 본 논문에서는 Anytime DRRT 기반 충돌회피 알고리즘에서 동적 장애물의 속도 벡터에 따른 타원형 충돌범위를 적용하여 알고리즘의 효율성을 개선하고자 하였다. 회전익, 고정익 무인기에 대한 충돌회피 시뮬레이션과 실험 환경을 구성 및 진행하고, 기존의 충돌범위를 적용하였을 때와 비교하여 개선된 충돌범위의 효과를 검증하였다. 이를 통해 장애물의 속도 벡터에 따른 타원형 충돌범위를 적용한 Anytime DRRT 충돌회피 알고리즘이 기존보다 효율적인 경로를 도출하는 것을 확인할 수 있다. Anytime DRRT(Directed Rapidly-exploring Random Tree) algorithm is a collision avoidance algorithm that improves convergence and reduces path generating time compared to the RRT algorithm, and it achieves optimality by iteratively computing paths during the update cycle of position information, and selecting the shortest path among them to enhance the optimality of the RRT algorithm. In this paper, we aimed to enhance the efficiency of the Anytime DRRT based collision avoidance algorithm by applying elliptical collision area according to the velocity vector of dynamic obstacle. We constructed and conducted collision avoidance simulations and experiments in environments involving rotary-wing and fixed-wing unmanned aerial vehicles(UAVs). We validated the effectiveness of the improved collision area by comparing them to the application of existing collision area. Through this, we confirmed that the Anytime DRRT based collision avoidance algorithm with elliptical collision area according to the velocity vector of obstacle, can generate yield more efficient paths compared to the existing method.

대장암 수술 후 항암치료 중 상악골에 발생한 침습적 모균증 1예

박찬휘,이일우,이정훈,홍성룡 대한이비인후과학회 부산,울산,경남 지부회 2013 임상이비인후과 Vol.24 No.2

The clinical manifestations of mucormycosis are similar to those of fulminant rhinosinusitis. It is also known as rhinocerebral mucormycosis because it begins from the sinonasal cavity and invades into the orbit or brain rapidly. Fungi in contact with sinonasal mucosa penetrate into tissue, and form blood clots in the vascular endothelium widely by inducing the ischemic lesion. In general, healthy people are not susceptible to them. However they progress rapidly in diabetic or immunocompromised patients. In this study, we report a case of 59-year-old woman with diabetes mellitus who developed invasive mucormycosis during postoperative chemotherapy for colorectal cancer and treated with administration of antifungal agent after partial maxillectomy.

율피 추출물 및 분획물의 항산화 활성

박찬휘,강현,이성규 한국식물생명공학회 2022 JOURNAL OF PLANT BIOTECHNOLOGY Vol.49 No.2

This study examined the antioxidant activity of ethanol extract and fraction from Castanea crenata inner shell in vitro. Antioxidant activity was evaluated through total polyphenol and flavonoid contents and DPPH radical scavenging ability using electron spin resonance (ESR). The total polyphenol contents of the 70% ethanol extract and ethyl acetate fraction were 39.76 mg GAE/g and 323.92 mg GAE/g (p < 0.05). The total polyphenol contents of the ethyl acetate fraction were higher than other fractions. Furthermore, the total flavonoid contents of ethyl acetate were higher than other fractions at 13.12 mg QE/g (p < 0.05). In DPPH radical scavenging ability measurement, the RC50 value of ethyl acetate was lower than ascorbic acid at 2.27 μg/mL (p < 0.05). In conclusion, this result showed that the ethyl acetate fraction of Castanea crenata inner shell 70% ethanol extract has high antioxidant activity.

인간성대 섬유아세포주에서 Acid와 Pepsin의 효과

박찬휘,신성찬,박희영,이병주 대한이비인후과학회 부산,울산,경남 지부회 2015 임상이비인후과 Vol.26 No.2

Background and Objectives:Laryngopharyngeal reflux, the backflow of gastric contents into the pharynx and larynx, is among the most important factors behind the development of inflammatory disorders of the upper airway. Our objective was to clarify the effects of exposure of the acid and pepsin in the laryngopharyngeal reflux disease by carrying out research on gene changes in the human vocal fold fibroblast. Material and Methods:To make a cell culture solution of acidic conditions of pH4 and 5 by using a 0.01 M hydrochloric acid. Pepsin was prepared in 0.5 mg/mL concentration dissolved in 0.9% sodium chloride. Pepsin was added to the cell culture fluid of pH4 and pH5 acid. The prepared acidic cell culture solution for each condition was treated for 5 minutes on the fibroblasts of the vocal folds. Then to remove the acidic cell culture solution, the vocal fold fibroblast culture fluid was incubated for 6 hours. After the culture, real time PCR, MTT assay and LDH assay were carried out. Results:The human vocal fold fibroblast in the pH4 acidic cell culture medium containing pepsin has the highest cell damage form. We confirmed these results by using the MTT assay and LDH assay. After incubation for 6 hours, it was confirmed that the cell was returned in the normal form of a vocal fold fibroblast in all experimental groups compared to the control groups. There are no significant differences of gene expression after acid and/or pepsin treatment in human vocal fold fibroblast. Conclusions:The most critical effect on the damage to the vocal fold cells was the interaction of pH4 acidic environment and pepsin than acting alone or pH5 environment.

속도벡터에 따른 타원형 충돌범위를 적용한 Anytime DRRT에 관한 연구

박찬휘(Chanhwi Park),이민규(Minkyu Lee),노기문(Geemoon Noh),이대우(Daewoo Lee) 한국항공우주학회 2022 한국항공우주학회 학술발표회 논문집 Vol.2022 No.4

Anytime DRRT 알고리즘의 고정익에 대한 적용과 gazebo 기반 시뮬레이션

박찬휘(Chanhwi Park),이민규(Minkyu Lee),노기문(Geemoon Noh),이대우(Daewoo Lee) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.4

유양동 수술 후 발생한 측두엽 농양 1예

고진영,박찬휘,이일우,오세준 대한이비인후과학회 2014 대한이비인후과학회지 두경부외과학 Vol.57 No.6

We report a case of complicated temporal lobe abscess following mastoidectomy. The patient complained of a headache after surgery, however, he was discharged as his symptom was considered to be a common postoperative headache. He revisited our due to a generalized tonic-clonic seizure, and the CT and MRI findings suggested the diagnosis of temporal lobe abscess. The patient was successfully treated with antibiotics instead of surgical treatment. Although the cerebral abscess following mastoidectomy is extremely rare, it is necessary to pay attention to it. Particularly when the patient complains of a headache, it is important to consider the aspects of headache carefully. Bone defect in tegmen tympani and exposure of dura will increase the risk of cerebral abscess, therefore careful caution is required in the presence of lower dura mater. Korean J Otorhinolaryngol-Head Neck Surg 2014;57(6):411-4

Simulink와 X-Plane을 이용한 모의 근접비행 시뮬레이션 환경 개발연구

이상훈,박찬휘,박영후,이대우 한국항공우주학회 2021 韓國航空宇宙學會誌 Vol.49 No.6

Prior to the actual flight test of the separation-reintegration situation of fixed-wing mother and child UAVs in the air, it is necessary to verify the flight control system of child UAV through simulations. In this paper, we build a simulation environment for the development of a child UAV flight control system in a lab environment based on the wake turbulence of X-Plane. To this end, the aerodynamics analysis of child UAV was performed, and Simulink was used to simulate aircraft, and X-Plane was utilized to implement visualization, wind, gusts, and mother UAV movements. The simulation environment built by performing simulated proximity flights was verified by applying the guidance and control algorithm to the child UAV model within Simulink. Furthermore, the flight results confirm the area in which the child UAV can safely fly from the rear of the mother UAV. 고정익 모선과 자선의 공중에서의 분리-재결합 상황에 대한 실제 비행시험 이전에 시뮬레이션을 통해 자선의 비행제어 시스템을 검증할 필요가 있다. 본 논문에서는 X-Plane의 후류 기능을 기반으로 연구실 환경에서 자선의 비행제어 시스템 개발을 위한 시뮬레이션 환경을 구축하였다. 이를 위해 자선의 공력해석을 수행하고 Simulink를 사용하여 항공기를 모사하였으며, X-Plane을 활용하여 시각화와 바람, 돌풍, 모선의 이동을 구현하였다. 유도제어 알고리즘을 Simulink 내 자선 모델에 적용하여 모의 근접비행을 수행함으로써 구축된 시뮬레이션 환경을 검증하였다. 또한 비행 결과를 통해 자선이 모선 후방에서 안전하게 비행할 수 있는 영역을 확인하였다.

A Case of Metallic Tracheostomy Tubes as Foreign Bodies Broken for a Long Time and Lodged in the Bilateral Main Bronchi

이석환,박찬휘,이일우,왕수건 대한이비인후과학회 부산,울산,경남 지부회 2013 임상이비인후과 Vol.24 No.1

The case that fragments of metallic tracheostomy tubes lodged in bilateral main bronchi as foreign bodies rarely occurs. A 52-year-old male presented with excessive cough and purulent sputum induced by fragments of metal-lic tracheostomy tube in both main bronchi and the left pleural effusion. With the assistance of anesthesiologist with abundant experience, ventilating bronchoscopy under local anesthesia was attempted, and both the frag-ments of tubes were removed by the order of the right and the left. The patient showed the rapid improvement of symptoms after ventilating brochoscopy. This case is the first report in the world literatures that successful remov-al of fragments of metallic tracheostomy tube lodged in the both main bronchi as foreign bodies was done under local anesthesia maintaining self-respiration.

PNUSAT-1 EM모델 열·진공 시험 및 결과

송우석,박찬휘,임재욱,조성현,이창현,권준수,노기문,조동현,이대우 한국항공우주학회 2023 韓國航空宇宙學會誌 Vol.51 No.5

PNUSAT-1 is the 1U-size cube satellite under development in cooperation with Flight Dynamics Laboratory and Space System Control Laboratory of Pusan National University. It is being developed for the purpose of delivering name, size and location of ship to ground stations using an Automatic Identification System(AIS), and hardware assembly and communication tests were constructed based on a pre-designed system. However, even for satellites that have conducted design and integration tests, it is essential to conduct a thermal vacuum test, one of the environmental tests simulating the space environment, in order to increase the possibility of mission success in extreme space environments. Therefore, in this paper, analyze the process and results of the thermal vacuum test conducted in advance to increase the mission success rate of PNUSAT-1. PNUSAT-1은 부산대학교 비행역학실험실과 우주시스템제어실험실이 공동으로 개발 중인 1U 크기의 큐브위성이다. 본 위성은 자동식별장치(Automatic Identification System, AIS)를 이용해 지상국에 선박의 이름, 크기, 위치 등을 전달하기 위한 목적으로 개발되고 있으며, 사전 설계된 시스템을 기반으로 하드웨어 조립 및 통신 테스트를 수행하였다. 하지만 설계 및 통합 테스트를 시행한 위성이라도 극한의 우주 환경에서 임무 성공 가능성을 높이기 위해서는 우주 환경을 모사한 환경시험 중 하나인 열·진공 시험을 수행하는 것은 필수적이다. 따라서 본 논문에서는 PNUSAT-1의 임무 성공률을 높이기 위해 사전에 실시한 열·진공 시험의 과정과 결과를 분석하여 큐브위성의 활성화에 도움을 주고자 한다.