• International Journal of Aeronautical and Space Sciences
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• 제7권2호
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• pp.121-127
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• 2006

An analysis procedure for the combined problem of control algorithm and aeroelastic system which is based on the computational fluid dynamics(CFD) technique has been developed. The aerodynamic forces in the transonic region are calculated from the transonic small disturbance(TSD) theory. An linear quadratic regulator(LQR) controller is designed to suppress the transonic flutter. The optimal control gain is estimated by solving the discrete-time Riccati equation. The system identification technique rebuilds the CFD-based aeroelstic system in order to form an adequate system matrix which involved in the discrete-time Riccati equation. Finally the controller, that is constructed on the basis of system identification technique, is used to suppress the flutter phenomenon of the airfoil with attached store. This approach, that is, the CFD-based aeroservoelasticity design, can be utilized for the development of effective flutter controller design in the transonic region.

• 한국항행학회논문지
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• 제13권6호
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• pp.813-819
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• 2009

무인항공기의 에일러론 및 플랩, 엘리베이터 등을 제어하기위한 작동기들은 구조적으로 Time variant한 비선형적인 특성을 가지고 있을 뿐 아니라, 비행 중에 풍향 및 풍량에 따라 모델링하기 힘든 외란이 발생할 경우가 많이 발생하기 때문에 우수한 제어성능을 보이는 제어기 설계에 많은 어려움이 있었다. 본 논문에서는 기존의 PID 제어기의 장점을 그대로 살리면서 실시간으로 변화하는 시스템에 adaptive하게 대응할 수 있고 Auto gain tuning을 이용하여 개발자의 시간과 노력을 현저히 줄일 수 있는 Fuzzy Auto gain tuning PID 제어 알고리즘을 비행체 Actuator 제어에 적용한 연구내용을 기술하였다.

• Archives of Plastic Surgery
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• 제48권4호
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• pp.404-409
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• 2021

Background To date, there are no consensus guidelines for management of lymphatic leak in groin vascular reconstruction patients. The goal of this study is to review the relevant literature to determine alternatives for treatment and to design an evidence-based algorithm to minimize cost and morbidity and maximize efficacy. Methods A systematic review of the literature was conducted per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Two independent reviewers applied agreed-upon inclusion and exclusion criteria to eligible records. Studies that included patients who underwent groin dissection for oncologic diagnoses and level 5 data were excluded. Interventions were then categorized by efficacy using predetermined criteria. Results Our search yielded 333 records, of which eight studies were included. In four studies, the success of lymphatic ligation ranged from 75% to 100%, with average days to resolution ranging from 0 to 9. Conservative management in the form of elevation, compression, and bedrest may prolong time to resolution of lymphatic leak (14-24 days) and therefore cost. Conclusions The majority of patients should be offered early operative intervention in the form of lymphatic ligation with or without a primary muscle flap. If the patient is not an operative candidate, a trial of conservative management should be attempted before other nonsurgical interventions.

• Archives of Plastic Surgery
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• 제41권6호
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• pp.716-721
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• 2014

Background The aim of this study was to review the recipient vessels used in our cases of facial reanimation with free functional muscle transfer and to identify patient variables that may predict when the facial vessels are absent. From this we present a protocol for vessel selection in cases when the facial artery and/or vein are absent. Methods Patients were identified from November 2006 to October 2013. Data was collected on patient demographics, facial palsy aetiology, history of previous facial surgery/trauma and flap/recipient vessels used. A standard operative approach was adopted and performed by a single surgeon. Results Eighty-seven eligible patients were identified for inclusion amongst which 98 hemifaces were operated upon. The facial artery and vein were the most commonly used recipient vessels (90% and 83% of patients, respectively). Commonly used alternative vessels were the transverse facial vein and superficial temporal artery. Those with congenital facial palsy were significantly more likely to lack a suitable facial vein (P=0.03) and those with a history of previous facial surgery or trauma were significantly more likely to have an absent facial artery and vein (P<0.05). Conclusions Our algorithm can help to guide vessel selection cases of facial reanimation with free functional muscle transfer. Amongst patients with congenital facial palsy or in those with a previous history of facial surgery or trauma, the facial vessels are more likely to be absent and so the surgeon should then look towards the transverse facial vein and superficial temporal artery as alternative recipient structures.

• 대한두개안면성형외과학회지
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• 제18권3호
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• pp.166-171
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• 2017

Background: Localized scleroderma is characterized by a thickening of the skin from excessive collagen deposits. It is not a fatal disease, but quality of life can be adversely affected due to changes in skin appearance, joint contractures, and, rarely, serious deformities of the face and extremities. We present six cases of localized scleroderma in face from our surgical practice. Methods: We reviewed six localized scleroderma cases that were initially treated with medication and then received follow-up surgery between April 2003 and February 2015. Six patients had facial lesions. These cases presented with linear dermal sclerosis on the forehead, oval subcutaneous and dermal depression in the cheek. Results: En coup de sabre (n=4), and oval-shaped lesion of the face (n=2) were successfully treated. Surgical methods included resection with or without Z-plasty (n=3), fat graft (n=1), dermofat graft (n=1), and adipofascial free flap (n=1). Deformities of the affected parts were surgically corrected without reoccurrence. Conclusion: We retrospectively reviewed six cases of localized scleroderma that were successfully treated with surgery. And we propose an algorithm for selecting the best surgical approach for individual localized scleroderma cases. Although our cases were limited in number and long-term follow-up will be necessary, we suggest that surgical management should be considered as an option for treating scleroderma patients.