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Three-Dimensional Printing: Basic Principles and Applications in Medicine and Radiology
Kim, Guk Bae,Lee, Sangwook,Kim, Haekang,Yang, Dong Hyun,Kim, Young-Hak,Kyung, Yoon Soo,Kim, Choung-Soo,Choi, Se Hoon,Kim, Bum Joon,Ha, Hojin,Kwon, Sun U.,Kim, Namkug The Korean Society of Radiology 2016 KOREAN JOURNAL OF RADIOLOGY Vol.17 No.2
<P>The advent of three-dimensional printing (3DP) technology has enabled the creation of a tangible and complex 3D object that goes beyond a simple 3D-shaded visualization on a flat monitor. Since the early 2000s, 3DP machines have been used only in hard tissue applications. Recently developed multi-materials for 3DP have been used extensively for a variety of medical applications, such as personalized surgical planning and guidance, customized implants, biomedical research, and preclinical education. In this review article, we discuss the 3D reconstruction process, touching on medical imaging, and various 3DP systems applicable to medicine. In addition, the 3DP medical applications using multi-materials are introduced, as well as our recent results.</P>
Kim Si-Ho,Hong Jin Yeong,Bae Seongman,Lee Hojin,Wi Yu Mi,Ko Jae-Hoon,Kim Bomi,Joo Eun-Jeong,Seok Hyeri,Shi Hye Jin,Yoo Jeong Rae,Hyun Miri,Kim Hyun ah,Jang Sukbin,Mun Seok Jun,Kim Jungok,Kim Min-Chul 대한의학회 2022 Journal of Korean medical science Vol.37 No.18
Background: Coronavirus disease 2019 (COVID-19) is often accompanied by secondary infections, such as invasive aspergillosis. In this study, risk factors for developing COVID-19- associated pulmonary aspergillosis (CAPA) and their clinical outcomes were evaluated. Methods: This multicenter retrospective cohort study included critically ill COVID-19 patients from July 2020 through March 2021. Critically ill patients were defined as patients requiring high-flow respiratory support or mechanical ventilation. CAPA was defined based on the 2020 European Confederation of Medical Mycology and the International Society for Human and Animal Mycology consensus criteria. Factors associated with CAPA were analyzed, and their clinical outcomes were adjusted by a propensity score-matched model. Results: Among 187 eligible patients, 17 (9.1%) developed CAPA, which is equal to 33.10 per 10,000 patient-days. Sixteen patients received voriconazole-based antifungal treatment. In addition, 82.4% and 53.5% of patients with CAPA and without CAPA, respectively, received early high-dose corticosteroids (P = 0.022). In multivariable analysis, initial 10-day cumulative steroid dose > 60 mg of dexamethasone or dexamethasone equivalent dose) (adjusted odds ratio [OR], 3.77; 95% confidence interval [CI], 1.03–13.79) and chronic pulmonary disease (adjusted OR, 4.20; 95% CI, 1.26–14.02) were independently associated with CAPA. Tendencies of higher 90- day overall mortality (54.3% vs. 35.2%, P = 0.346) and lower respiratory support-free rate were observed in patients with CAPA (76.3% vs. 54.9%, P = 0.089). Conclusion: Our study showed that the dose of corticosteroid use might be a risk factor for CAPA development and the possibility of CAPA contributing to adverse outcomes in critically ill COVID-19 patients.
김호진(Hojin Kim),김중관(Joong-Kwan Kim),김준환(Junhwan Kim),김현석(Hyunsuk Kim),위혁(Hyuk Wee) 한국방재안전학회 2023 한국방재안전학회 논문집 Vol.16 No.3
본 연구에서는 능동소음제어(ANC) 기술을 층간소음 분야에 적용하기 위하여 40~500 Hz 대역의 중량충격음을 제어하기 위한 ANC 시스템을 구성하였다. ANC 시스템에는 Fx-LMS 알고리즘 기반의 적응형 필터를 활용한 피드포워드 방식의 제어기술을 도입하였다. ANC 시스템 설정을 위해 가상 시뮬레이션을 통해 ANC를 구성하는 변수 연구를 실시하였고, 이를 통해 최적 필터와 시스템 배치 방법을 정립하였다. 또한 본 연구에는 개발된 ANC 시스템을 한국건설생활시험연구원(KCL)의 층간소음 시험실에 설치한 후 표준시험방법에 따라 ANC 시스템 구동 전후 4 dB의 층간소음 저감효과를 확인하였다. 시험결과를 통해 본 연구에서 개발한 ANC 시스템이 중량충격음에 대한 등급 기준을 한 단계를 상향시킬 수 있는 수준의 효과가 있음을 확인하였다. In this study, the application of ANC (Active Noise Control) technology to address inter-floor noise was explored. To achieve this, an ANC system was developed to manage the heavy impact sound within the frequency range of 40 to 500 Hz. The ANC system utilized an adaptive filter employing a feedforward approach based on the Fx-LMS algorithm. To set up the ANC system, a comprehensive analysis of various variables within the system was performed using computational simulations. This process enabled the identification of optimal filter settings and system configuration arrangements. In addition, the ANC system was implemented in the inter-floor noise test room at the Korea Conformity Laboratories (KCL). Through a certified standard testing procedure, it was confirmed that the ANC system led to a 4 dB reduction in inter-floor noise when the system was activated compared to when it was turned off. The results of this study indicate that the developed ANC system has an effect significant enough to elevate the rating criteria by one level for heavy impact sound.
Mid-Air Tactile Stimulation Using Indirect Laser Radiation
Lee, Hojin,Kim, Ji-Sun,Kim, Jae-Young,Choi, Seungmoon,Jun, Jae-Hoon,Park, Jong-Rak,Kim, A-Hee,Oh, Han-Byeol,Baek, Jun-Hyeok,Yang, Seung-Jin,Kim, Hyung-Sik,Chung, Soon-Cheol IEEE 2016 IEEE transactions on haptics Vol.9 No.4
<P>In this paper, we demonstrate that a laser irradiated on a thin light-absorbing elastic medium attached on the skin can elicit a tactile sensation of mechanical tap. First, we present simulation results that show laser irradiation to the elastic medium creates inner elastic waves on the basis of thermoelastic effects and these elastic waves trigger the bending deformation of the medium, which then stimulates the skin. Second, we analyze the physical properties of the associated stimulus by measuring its force profile. Third, we identify the perceptual characteristics of the stimulus in comparison to those of mechanical and electrical stimuli by means of a perceptual experiment employing dissimilarity rating. All the evidence indicates that indirect laser radiation provides a sensation of short mechanical tap. Furthermore, little individual difference was observed in the results of the perceptual experiment. To the best of our knowledge, this study is the first in reporting the feasibility of indirect laser radiation for mid-air tactile rendering.</P>
Post-Stenotic Recirculating Flow May Cause Hemodynamic Perforator Infarction
Bum Joon Kim,Hojin Ha,Hyung Kyu Huh,Guk Bae Kim,Jong S. Kim,Namkug Kim,Sang-Joon Lee,Dong-Wha Kang,Sun U. Kwon 대한뇌졸중학회 2016 Journal of stroke Vol.18 No.1
Background and Purpose The primary mechanism underlying paramedian pontine infarction (PPI) is atheroma obliterating the perforators. Here, we encountered a patient with PPI in the post-stenotic area of basilar artery (BA) without a plaque, shown by high-resolution magnetic resonance imaging (HR-MRI). We performed an experiment using a 3D-printed BA model and a particle image velocimetry (PIV) to explore the hemodynamic property of the post-stenotic area and the mechanism of PPI. Methods 3D-model of a BA stenosis was reconstructed with silicone compound using a 3D-printer based on the source image of HR-MRI. Working fluid seeded with fluorescence particles was used and the velocity of those particles was measured horizontally and vertically. Furthermore, microtubules were inserted into the posterior aspect of the model to measure the flow rates of perforators (pre-and post-stenotic areas). The flow rates were compared between the microtubules. Results A recirculating flow was observed from the post-stenotic area in both directions forming a spiral shape. The velocity of the flow in these regions of recirculation was about one-tenth that of the flow in other regions. The location of recirculating flow well corresponded with the area with low-signal intensity at the time-of-flight magnetic resonance angiography and the location of PPI. Finally, the flow rate through the microtubule inserted into the post-stenotic area was significantly decreased comparing to others (P<0.001). Conclusions Perforator infarction may be caused by a hemodynamic mechanism altered by stenosis that induces a recirculation flow. 3D-printed modeling and PIV are helpful understanding the hemodynamics of intracranial stenosis.
K-city 자율주행 경진대회 참가를 위한 자율주행 플랫폼 개발
김태호(Teaho Kim),김동진(Dongjin Kim),민동규(Dongkyu Min),서현지(Hyeonji Seo),윤호진(Hojin yun),정은빈(Eunbin Jung),이진강(Jingang Lee),권혁재(Hyeokjae Kwon),김진석(Jinseok Kim),김대국(Daekuk Kim),문일주(Iljoo Moon),유정흠(Jeongheum You 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
In this paper, a ROS-based autonomous driving framework designed by team ACCA from the School of Mechanical Engineering, Soongsil University, for the 2021 international college student creative car challenge held in K-city. The autonomous vehicle’s chassis used in this challenge is equipped with Velodyne 3D lidar, a Sick down-looking 2D lidar, Xsens MTi-30 AHRS, CCD camera, webcam, and PC-based controller. First, before the challenge in K-city, we evaluated the ROS-package-based SLAM such as LIO-SAM in a ring-shaped road environment on the campus of Soongsil University. After the successful SLAN and mapping process, the hdl_localization, which is a 3D lidar-based real-time 3D localization package, is used to estimate the global pose with respect to the global frame using NDT scan matching. For lane detection, traffic sign, and traffic signal recognition, the two well-known DNN models are utilized. Based on experimental results from both simulation and an actual autonomous vehicle platform, the Point Instance Network (PINet) for lane detection shows 88% of test accuracy, and the YOLO V4 for the traffic light and sign recognition offers 95% test accuracy.
Kim, Hojin,Kwak, Jungwon,Jeong, Chiyoung,Cho, Byungchul Korean Society of Medical Physics 2017 의학물리 Vol.28 No.3
Eclipse Scripting Application Programming Interface (ESAPI) was devised to enhance the efficiency in such treatment related workflows as contouring, treatment planning, plan quality measure, and data-mining by communicating with the treatment planning system (TPS). It is provided in the form of C# programming based toolbox, which could be modified to fit into the clinical applications. The Scripting program, however, does not offer all potential functionalities that the users intend to develop. The shortcomings can be overcome by combining the Scripting programming with user-executable program on Windows or Linux. The executed program has greater freedom in implementation, which could strengthen the ability and availability of the Scripting on the clinical applications. This work shows the use of the Scripting programming throughout the simple modification of the given toolbox. Besides, it presents the implementation of combining both Scripting and user-executed programming based on MATLAB, applied to automated dynamic MLC wedge and FIF treatment planning procedure for promoting the planning efficiency.