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Jeong-Ik Park,Youngjin Jang,Hojong Park,Sungchoul Pyun,Hong Rae Cho,Sang Jun Park 대한외과학회 2024 Annals of Surgical Treatment and Research(ASRT) Vol.106 No.1
Purpose: This study aims to investigate regional patterns and graft survival rates in kidney transplantation (KT) within South Korea using the National Health Insurance Service database. Methods: By analyzing KT data from 2002 to 2017, including patient residency, KT location, and post-KT dialysis information, graft survival was assessed through post-KT dialysis and validated against Ulsan University Hospital and the Korean Organ Transplantation Registry’s 2017 report. Results: Among the 20,978 KTs, 60.5% occurred in the Korean capital, Seoul, whereas 39.5% occurred outside. The overall graft survival rate was 81.5% with a median survival duration of 57 months. Patient survival was 83.8%, with a median survival duration of 61 months. For KTs from 2002 to 2007, the 10-year graft and patient survival rates were 89.1% and 90.3%, respectively. The KT recipients living outside Seoul who underwent the KT within their residential regions had a graft survival rate of 88.3%, and those receiving KTs outside their original region had a graft survival rate of 88.0%. Among Seoul residents who underwent KTs in the city, the graft survival rate was 90.5%. Importantly, hospital location did not significantly affect graft survival rates (P = 0.136). Conclusion: This study revealed a regional preference for KT in South Korea, particularly in the capital city, likely because of nonresidents. Nevertheless, the graft and patient survival rates showed no significant regional disparities. These findings emphasize the necessity for equitable KT service access across regions in order to optimize patient outcomes.
Sangmin Gong,Eun Ji Lee,Jin Sung Kim,Hyangkyoung Kim,Minsu Noh,Hojong Park,Bong Won Park,Songsoo Yang,Sang Jun Park 대한혈관외과학회 2021 Vascular Specialist International Vol.37 No.2
Purpose: The aim of this study was to investigate the relationship between the anatomical location of thrombi in the lower extremities and the development of pulmonary embolism (PE). Materials and Methods: We collected and analyzed the data of patients diagnosed with deep vein thrombosis (DVT) of the lower extremities between 2006 and 2015, and included those whose computed tomography (CT) data were available for PE identification. We evaluated the relationship between the laterality and the proximal/ distal location of the thrombi in lower extremites and the location of PE. Results: CT images were available for 388/452 patients with DVT. After excluding 32 cases with bilateral involvement, 356 cases were included for analysis in this study. The ratio of DVT in the left:right leg was 232:124. PEs developed in 121 (52.2%) patients with left-sided DVT and in 78 (62.9%) with right-sided DVT (P=0.052). PEs in the main pulmonary arteries developed in 36 (15.5%) patients with left leg DVT and in 30 (24.2%) with right leg DVT (P=0.045). The most frequent site of thrombosis associated with the development of PE was the left iliac vein (59/199, 29.6%). According to the anatomical segment of the leg affected by DVT, patients with DVT in the right femoral vein (50/71, 70.4%; P=0.016) had the highest rate of occurrence of PE. Conclusion: PE develops more frequently in patients with right-sided DVT than in those with left-sided DVT. Therefore, careful observation for the possible development of PE is recommended in cases with right-sided DVT of the lower extremity.
Improvement of spatial resolution in a Timepix based CdTe photon counting detector using ToT method
Park, Kyeongjin,Lee, Daehee,Lim, Kyung Taek,Kim, Giyoon,Chang, Hojong,Yi, Yun,Cho, Gyuseong Elsevier 2018 Nuclear instruments & methods in physics research. Vol.891 No.-
<P><B>Abstract</B></P> <P>Photon counting detectors (PCDs) have been recognized as potential candidates in X-ray radiography and computed tomography due to their many advantages over conventional energy-integrating detectors. In particular, a PCD-based X-ray system shows an improved contrast-to-noise ratio, reduced radiation exposure dose, and more importantly, exhibits a capability for material decomposition with energy binning. For some applications, a very high resolution is required, which translates into smaller pixel size. Unfortunately, small pixels may suffer from energy spectral distortions (distortion in energy resolution) due to charge sharing effects (CSEs). In this work, we propose a method for correcting CSEs by measuring the point of interaction of an incident X-ray photon by the time-of-threshold (ToT) method. Moreover, we also show that it is possible to obtain an X-ray image with a reduced pixel size by using the concept of virtual pixels at a given pixel size. To verify the proposed method, modulation transfer function (MTF) and signal-to-noise ratio (SNR) measurements were carried out with the Timepix chip combined with the CdTe pixel sensor. The X-ray test condition was set at 80 kVp with 5 μ A, and a tungsten edge phantom and a lead line phantom were used for the measurements. Enhanced spatial resolution was achieved by applying the proposed method when compared to that of the conventional photon counting method. From experiment results, MTF increased from 6.3 (conventional counting method) to 8.3 lp/mm (proposed method) at 0.3 MTF. On the other hand, the SNR decreased from 33.08 to 26.85 dB due to four virtual pixels.</P>
Hojong Gil,Sihyun Ryu,Sang-Kyoon Park,Jiseon Ryu 대한인간공학회 2018 大韓人間工學會誌 Vol.37 No.6
Objective: The purpose of this study was to determine the difference of motions using the new calculation method of COP area and to investigate the correlation with the change of the foot eversion. Background: The quantitative analysis process on the data of COP revealed in the process of repetitive gait and running cycle is essentially required and through COP trajectories, the correlations between ground and feet can be effectively examined. Method: Thirty young males participated in this study. They were asked to run on an instrumented treadmill (Bertec, USA) at speeds of 3.5m/s and 4.5m/s for running. A system of motion analysis cameras (Oqus 300, Qualisys, and Sweden) and pedar-X system (Novel GmbH, Germany) were used to collect joint angles and COP trajectories, and Shoelace Formula was used to calculate the area of multiple COP lines from running. The analysis variables were the area of COP, the COP range, the COP velocity, and the ankle joint eversion angle. The Pearson"s correlation coefficient was calculated to investigate the relations between variables. Results: The running at 4.5m/s showed the smaller area of COP and the range of COP, but the greater velocity of COP (p <0.05) in comparison with the running at 3.5m/s. There was a positive correlation between the area of COP and the anteriorposterior range of COP (r =.350). Additionally, there was a negative correlation between the area of COP and the maximum eversion angle of ankle joint (r =-.418). Conclusion: The findings indicate that the method using the Shoelace Formula to calculate the area of COP was able to determine the difference between running speeds and predict the maximum eversion angle of the ankle joint. Application: Based the results, the area of COP trajectories newly presented in this study is judged to be used as a variable to predict running speed and the eversion angle of the ankle joint.
박장훈(PARK, Janghoon),구성관(KU, Sungkwan),백호종(Baik, Hojong) 대한교통학회 2013 대한교통학회 학술대회지 Vol.69 No.-
전자장비의 눈부신 발전과 더불어 인공위성의 위치추적기능을 이용한 항공기 항행장비의 발달은 항공관제시스템의 패러다임을 변화시키는 획기적인 원동력으로 작용하고 있다. 특히, International Civil Aviation Organization(ICAO, 국제민간항공기구)가 중심이 되어 추진되고 있는 Performance Based Navigation(PBN, 성능기반항행) 전환사업은 기존의 지상기반(Ground Based) 항행장비에 기 초하여 설계된 항로를 첨단화된 항공기의 성능에 적합한 보다 효율적인 신규 항로로 개편하는 사업으로, 우리나라도 정해진 로드맵 의 일부 공역에서는 이미 새로운 항로를 공포, 운영 중에 있다. 일례로, 그동안 단선으로 설계․운영되어 오던 우리나라 주요 남북항 로인 B576항로(서울-제주 간 연결)는 2012년 6월 28일부터 Y71(하행), Y72(상행) 복선항로로 개편․운영되고 있다. 본 연구에서는, 이러한 복선화 사업의 시행으로 나타난 항공기 운항효율성 향상에서 비롯되는 경제적 편익을 추정하고자 한다. 다른 교통수단과는 달리, 항공교통은 항공기의 항적에 관한 자료가 레이더 장비를 통해 수집․기록되며, 이를 이용한 다양한 형태의 연구가 가능하다는 특성이 있다. 본 연구에서는 B576항로 복선화 전후 수집된 항공기 항적자료를 이용하여, 항로 복선화에 따른 항공기의 운항효율성 을 계량적으로 비교분석하였다. 분석을 위해 항공기 운항속도, 연료소비량를 계량화 지표로 사용되었으며, 이 가운데 연료소비량은 EUROCONTROL이 제공하는 Base of Aircraft Data(BADA) 자료를 활용하여 산정하였다. 더불어, BADA 자료의 국내 적용을 위하 여 실제로 집계된 항공기 연료소비량 자료와 추정된 연료소비량 자료를 비교․평가하는 과정을 거쳤다. 분석결과 B576항로의 복선 화로 인해 항공기 운항속도는 17 knots(약 4.17%) 빨라졌으며, 이로 인한 항공기 운항시간은 1.2분(약 3.55%) 단축된 것으로 나타났 다. 연료소비량 역시 B576항로의 복선화로 항공기당 평균 228.4 kg(약 5.5%) 감소한 것으로 나타났다.