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소형 드론을 위한 주파수 영역 식별과 모델 기반 외란 관측기
정규환,안형준 한국정밀공학회 2023 한국정밀공학회지 Vol.40 No.5
Drone is an innovative industry that can combine the application of various technologies in the fourth industrial era, such as big data, artificial intelligence, and ICT. Although the synergy effects of these technologies will be great in various industrial ecosystems, drones are vulnerable to gusts such as 'building wind' or 'valley wind'. Herein, the frequency domain of a mini drone was identified and a model-based disturbance observer (DOBs) was applied to implement the drone robust resistance against gusts. The frequency response of the Parrot Mambo or mini drone was measured with multi-sine excitation and the system dynamic parameters were identified. Based on the identified model, DOBs were designed and applied to the drone’s altitude, position, and yaw control. The effectiveness of the DOBs was verified with a sinusoidal disturbance. With the model-based DOB, 84.5% of the drone altitude responses, 50.7% of x responses, 52.1% of y responses, and 79.7% of yaw responses against sinusoidal disturbances were reduced. Flight responses were measured against wind disturbances with changing speed and direction. With the model-based DOBs, the drone's altitude decreased by 87.7%, the x position by 53.0%, the y position by 60.6%, and the yaw angle by 56.2%.
정규환,정재현,안태식,이중섭,조성용,정창욱,이승배,김현회,오승준 대한비뇨의학회 2015 Investigative and Clinical Urology Vol.56 No.7
Purpose: To investigate surgical outcomes between retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL)groups for a main stone sized 15 to 30 mm and located in the lower-pole calyx. Materials and Methods: Patients who underwent PNL or RIRS for a main stone sized 15 to 30 mm and located in the lower-polecalyx were retrospectively reviewed. Each patient in the RIRS group was matched to one in the PNL group on the basis of calculatedpropensity scores by use of age, sex, body mass index, previous treatment history, stone site, maximum stone size, and stonevolume. We compared perioperative outcomes between the unmatched and matched groups. Results: Patients underwent PNL (n=87, 66.4%) or RIRS (n=44, 33.6%). After matching, 44 patients in each group were included. Mean patient age was 54.4±13.7 years. Perioperative hemoglobin drop was significantly higher and the hospital stay was longer inthe PNL group than in the RIRS group. The operative time was significantly longer in the RIRS group than in the PNL group. Stonefreerates were higher and complications rates were lower in the RIRS group than in the PNL group without statistical significance. The presence of a stone located in the lower-anterior minor calyx was a predictor of stone-free status. Conclusions: RIRS and single-session PNL for patients with a main stone of 15 to 30 mm located in the lower-pole calyx showedcomparable surgical results. However, RIRS can be performed more safely than PNL with less bleeding. Stones in the lower-anteriorminor calyx should be carefully removed during these procedures.
만성 부비동염 환자에서의 비강 내 Helicobacter Pylori집락화에 대한 연구
정규환,동헌종,정승규,김효열,정영준,소윤경 대한이비인후과학회 2006 대한이비인후과학회지 두경부외과학 Vol.49 No.2
Background and Objectives:Helicobacter pylori (HP) has been reported to be detected in lower esophagus, palatine tonsil, and adenoid. The object of this study was to investigate the prevalence of HP in the nasal cavity of chronic rhinosinusitis (CRS) patients and compare the results with those of healthy controls. Subjects and Method:43 patients aged 18 to 68 years with CRS who underwent endoscopic sinus surgery and 16 healthy controls aged 24 to 72 years without sinus diseases were enrolled in this study. Tissue samples were collected from nasal polyp or the mucosa of sphenoethmoidal recess. HP infection of nasal cavity was investigated using rapid urease (CLO) test and immunohistochemical (IHC) analysis. GER symptoms and esophagogastroscopic findings were gathered by questionnaire or medical records. Results:HP was detected in nasal cavity by CLO test in 17 of 43 patients (40%) with CRS compared with none of 16 healthy controls (0%) (p=0.003), and 19 of 43 patients (44%) by IHC analysis compared with 2 of 16 healthy controls (13%) (p=0.032). Eleven of 43 patients (26%) were positive in both CLO test and IHC analysis but none of controls (0%) was positive in both two tests (p=0.026). Four of 8 patients (50%) who complained GER specific symptoms were HP positive in both two tests (p=0.033). Conclusion:HP was detected in nasal cavity and it was more prevalent in patients with CRS than healthy controls without sinus diseases. GER may have a positive correlation with the colonization of HP. However, whether HP is a causative agent for CRS or a result of CRS is not known. (Korean J Otolaryngol 2006;49:162-7)