• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.357-360
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• 1997

For medical students and doctors, knowledge of the 3-dimensional (3D) structure of the heart is very important in diagnosis and treatment of the heart diseases. 2-dimensional (2D) tools (e.g. anatomy book) or classical 3D tools (e.g. plastic model) are not sufficient or understanding the complex structures of the heart. Moreover, it is not always guaranteed to dissect the heart of cadaver when it is necessary. To overcome this problem, virtual dissection systems of the heart have been developed. But these systems are not satisfactory since they are made of radiographs; they are not true 3D images; they can not be used to dissect freely; or they can only be operated on the workstation. It is also necessary to make the dissection systems incorporating the various races and tribes because of the organ's difference according to race and tribe. This study was intended to make the 3D image of the heart from a Korean cadaver, and to establish a virtual dissection system of the heart with a personal computer. The procedures or manufacturing this system were as follows. 1. The heart from a Korean adult cadaver was embedded with gelatin solution, and serially cross-sectioned at 1mm-thickness on a meat slicer. Pictures or 153 cross-sectioned specimens were inputted into the computer using a digital camera ($756{\times}504$ resolution, true color). 2. The alignment system was established by means of the language of IDL, and applied to align 2D images of the heart. In each of 2D images, closed curves lining clean and dirty blood pathways were drawn manually on the CorelDRAW program. 3. Using the language of IDL, the 3D image and the virtual dissection system of the heart were constructed. The virtual dissection system of the heart allowed or ree rotation, any-directional sectioning, and selected visualization of the heart's structure. This system is expected to become more advanced, and to be used widely through Internet or CD-title as an educational tool for medical students and doctors.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.58.1-58.1
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• 2005

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2005년도 제5회 학술대회 초록집
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• pp.47-50
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• 2005

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.287-288
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• 1998

The virtual surgery of Artificial Heart has focused on the simple fitting trial. But, as the processes of heart surgery being complex and detail, the requests of virtual surgery become more complex. One of the complex requests is volume editing. It may contain various editing functions: 3-dimensional cutting, registration, merging, splitting, inserting, deleting, translation and deformation. We have designed and implemented 3-dimensional volume editor that can be operated in Windows NT platform. With the results of this research, we can get convenient tools for the total virtual surgery system.

• 정보학연구
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• 제9권1호
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• pp.9-19
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• 2006

Medications or conitive-behavior methods have been mainly used as a treatment of alcoholism. lately the virtualy technology has been applied to the kink of alcoholic disorders. A virtual environment makes him having avility to over come the drink. In this study, we were implemented by making panorama images and 3D object modules using 3D MAX, VRML, JAVA. And the BAR stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a alcoholism and without a liquor bottle, heart rate was measured during experiment, and also measured a person's HR after the virtual reality training. The system measures the Physiological signals such as ECG, Temperature, analyzes those data automatically. The system has two parts, one is physiological data acquisition part which gets the body signal, and the other one is mobile nuit which includes signal processing and transmission functions, And Bluetooth allows two parts to communicate with each other. we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• The Korean Journal of Physiology and Pharmacology
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• 제23권1호
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• pp.63-70
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• 2019

We aimed to propose a novel computational approach to predict the electromechanical performance of pre- and post-mitral valve cerclage annuloplasty (MVCA). Furthermore, we tested a virtual estimation method to optimize the left ventricular basement tightening scheme using a pre-MVCA computer model. The present model combines the three-dimensional (3D) electromechanics of the ventricles with the vascular hemodynamics implemented in a lumped parameter model. 3D models of pre- and post-MVCA were reconstructed from the computed tomography (CT) images of two patients and simulated by solving the electromechanical-governing equations with the finite element method. Computed results indicate that reduction of the dilated heart chambers volume (reverse remodeling) appears to be dependent on ventricular stress distribution. Reduced ventricular stresses in the basement after MVCA treatment were observed in the patients who showed reverse remodeling of heart during follow up over 6 months. In the case who failed to show reverse remodeling after MVCA, more virtual tightening of the ventricular basement diameter than the actual model can induce stress unloading, aiding in heart recovery. The simulation result that virtual tightening of the ventricular basement resulted in a marked increase of myocardial stress unloading provides in silico evidence for a functional impact of MVCA treatment on cardiac mechanics and post-operative heart recovery. This technique contributes to establishing a pre-operative virtual rehearsal procedure before MVCA treatment by using patient-specific cardiac electromechanical modeling of pre-MVCA.

• 대한의용생체공학회:의공학회지
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• 제41권3호
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• pp.128-137
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• 2020

Cardiac electrophysiology studies often use simulation to predict how cardiac will behave under various conditions. To observe the cardiac tissue movement, it needs to use the high--resolution heart mesh with a sophisticated and large number of nodes. The higher resolution mesh is, the more computation time is needed. To improve computation speed and performance, parallel processing using multi-core processes and network computing resources is performed. In this study, we compared the computational speeds of CPU parallelization and GPU parallelization in virtual heart simulation for efficiently calculating a series of ordinary differential equations (ODE) and partial differential equations (PDE) and determined the optimal CPU and GPU parallelization architecture. We used 2D tissue model and 3D ventricular model to compared the computation performance. Then, we measured the time required to the calculation of ODEs and PDEs, respectively. In conclusion, for the most efficient computation, using GPU parallelization rather than CPU parallelization can improve performance by 4.3 times and 2.3 times in calculations of ODEs and PDE, respectively. In CPU parallelization, it is best to use the number of processors just before the communication cost between each processor is incurred.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2690-2692
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• 2004

Medications or cognitive-behavior methods have been mainly used as a treatment of alcoholism. lately the virtualy technology has been applied to the kink of alcoholic disorders. A virtual environment makes him having ability to over come the drink. In this study, we were implemented by making panorama images and 3D object modules using 3D Studio MAX. VRML, JAVA Applet. And the BAR stimulator that composed with a position sensor head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a alcoholism and and without a liquor bottle, heart rate was measured during experiment, and also measured a Person's HR after the virtual reality training. we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.587-589
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• 1997

The virtual surgical trial of TAH is very important in some points as follows. The chests of patients who is under heart-disease are various types of undefine form. It is hard to say that there exist the standard shape of TAH and the position to surgern. So, the virtual surgery system is very important in realizing TAH surgery of human. We have implemented virtual surgery system of TAH that supporting multi volume fitting trial. We have acquired CT images of patients with DICOM format. Each organ of patients was segmented in 2-dimensional CT images. 3-dimensional objects were made with marching cube algorithm and save as file in VRML format. Virtual fitting trial was performed on Cosmo-World; a VRML editor. The collision points of TAH with other organs were well observed. And the best position and angles were determined and saved or each case. We believed that this virtual surgery will be helpful in TAH surgery and TAH customizing.

• 한국산림과학회지
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• 제108권3호
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• pp.440-453
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• 2019

본 연구는 평면 숲동영상 및 VR 숲동영상 시청이 성인의 스트레스 감소에 미치는 영향을 밝히기 위해 수행되었다. 실험은 인공기후실에서 진행되었으며, 피험자는 40명이 참가하였다. 피험자의 스트레스를 유발한 후 2D 회색동영상, 2D 숲동영상, VR 숲동영상을 5분 동안 시청하게 하였다. 실험하는 동안 연속적으로 심박변동성을 측정하여 자율신경계 활동을 평가하였으며, 각 실험 후 설문지를 이용하여 심리 상태를 평가하였다. 생리적 측정 결과 2D 숲동영상은 2D 회색동영상보다 스트레스 지수 감소효과가 크고, HF 증가효과가 크며, 심장박동수 감소효과가 크다는 사실을 확인하였다. 또한 VR 숲동영상은 2D 회색동영상 시청보다 스트레스 지수 감소효과가 크고, LF/HF 증가효과가 크며, 심장박동수 감소효과가 크다는 사실을 확인하였다. 심리적 측정 결과 피험자들은 2D 회색동영상보다 2D 숲동영상과 VR 숲동영상을 더 쾌적하고, 자연적이며, 진정된다고 느꼈다는 사실을 확인하였다. 그리고 2D 숲동영상과 VR 숲동영상이 2D 회색동영상보다 긍정적인 정서를 증가시키고 부정적인 정서를 감소시킨다는 사실을 확인하였다. 이상의 결과를 바탕으로 2D 숲동영상과 VR 숲동영상의 시청은 스트레스 상황을 벗어나 2D 회색동영상을 시청하는 것보다 더 스트레스 지수를 감소시키고, 심장박동수를 감소시키는 것으로 판단된다. 또한 2D 숲동영상은 부교감 신경계의 활동을 증가시키고 VR 숲동영상은 교감 신경계의 활동을 증가시키는 차이점이 있는 것으로 판단된다. 마지막으로 VR 숲동영상의 교감 신경계의 활동 증가는 스트레스, 긴장 등의 부정적 교감신경 활성이 아닌 신기함, 호기심 등의 긍정적 교감신경 활성으로 판단된다. 이러한 연구의 결과가 산림치유의 시각적 효과에 대한 기반이 되길 기대하고, 임업분야에서 4차 산업혁명의 기술인 VR의 활용이 넓어지는 기반이 되길 기대한다.