• Journal of the Korean Society of Radiology
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• v.6 no.4
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• pp.305-311
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• 2012

This study compares the TE and UTE is to evaluate. We was programming by DWT of Matlab Tool-box for evaluation. M-program used feature value extract between TE Images and UTE Images. Two images using the extracted feature values were compared. Comparison of similar features two images phase was found to have value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3567-3573
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• 2009

This research proposed a dashpot type mount design using MR fluids, and investigated experimentally the influence of the design parameters of the dashpot MR fluid mount, which affect the damping forces of the dashpot MR fluid mount. In order to observe the influence, the dashpot MR fluid mount which have the different effective length and the core structure is manufactured. The variations of the resistance forces according to different effective lengths of the magnetic pole of MR fluid mount, along which magnetic field is defined, was investigated. It was founded that the resistance forces from the MR mount decreased with increased input frequencies, while increased with increased applied electric current intensities. Nevertheless, there is no appreciable change in the resistance forces with respect to the effective length variations of the magnetic pole of MR fluid mount.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.78-78
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• 2003

목적： 이전에는 손쉽게 구할 수 있는 표준데이터를 가지고 visual human body model을 형성하였다. 주로 팬텀이나, 외국인의 데이터를 가지고 만든 것이기 때문에 우리가 실제 실험에 쓰려면 큰 차이가 있었다. 그래서 본 연구에서는 실제 우리나라 사람 중 동일 인물의 MR와 CT 이미지를 가지고 인체 모델을 만들고자 하였다. 그러기 위해서 먼저 인체의 MR, CT영상에 대한 특징을 분석해야 했고, 이것을 바탕으로 영상 분할(Image Segmentation)을 하였다. 인체 부위에 따라 영상 분할 방법도 그 차이가 있음을 알 수 있었다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.485-488
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• 2002

본 논문은 의학 연구 및 교육, 환자 치료를 위해 보다 정확한 정보를 제공하고자 의료 영상 중에 가장 많이 사용하는 의료 영상인 뇌 MR 영상의 횡단면만을 가지고 3차원으로 가시화한다. 3차원으로 재구성하는데 있어서 원 영상의 모형을 자연스러운 표현을 위해서는 층 영상과 층 영상간의 보간 영상이 필요하므로 이를 생성하는 방법에 대해서 제안한다. 그리고 3차원 재구성에 필요한 정보를 추출하기 위해 각 영상에서 머리와 뇌 영역의 윤곽선 정보를 추출하고 가시화의 시간을 줄이기 위해 윤곽선 정보에서 특징점을 추출하여 이를 기반으로 하여 3차원으로 재구성 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2878-2885
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• 2012

In this study, the training and sporting equipment for leg rehabilitation featuring the MR fluids is proposed. The compact MR fluid brake is designed and manufactured to apply to the rehabilitation training and sporting mechanism. The resistance characteristic of the MR fluid brake is controllable by varying the magnetic field around the fluid. Under consideration of spatial limitation, design parameters which are related with the magnetic strength are determined to maximize to a torque using finite element method. The FE analysis is performed using a commercial code, ANSYS Workbench. The proposed brake device is manufactured, and its field-dependant torque is experimentally evaluated. When the electric current is supplied, the torque of the MR fluid brake is increased and the response is very fast. Depending on the strength of the current supply, torques of the MR fluid brake also increase similar to Bingham property of MR fluid.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.185-187
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• 2012

In this paper, the MR fluid damper to the application of the paramagnetic (paramagnetic) particles dispersed in the MR fluid inside the magnet current caused by the MR damper using the principles of the internal fluid delivery yield stress variation is characterized in Silky. In other words, the current strength of the MR fluid damper according to the internal friction coefficient varies phenomenon is to use. The MR fluid damper to control the MCU that you want to use Microchip's dsPIC chips, and current control in order to improve performance by using the PWM and UART communication to an external monitor to monitor the entire system was designed. In this study using MR fluid dampers and dsPIC chip dehydration process happens when a washing machine vibration and noise, vibration and noise reduction sikidorok washing machine protection systems are proposed.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.433-435
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• 2008

본 연구에서는 MR 유체를 특징으로 하는 대시포트형 마운트를 제안하고, 자극 형상의 변화가 MR유체 마운트의 감쇠력에 미치는 영향에 대하여 고찰하였다. 제안된 MR유체 마운트의 코어부에 발생하는 자기 특성에 대하여 살펴보기 위하여 자극(Magnetic pole)의 유효길이와 코어 중심부의 구조를 달리하여 대시포트를 제작하였다. 등가자기회로를 이용한 대략적인 계산방법에 의한 결과 자극의 유효길이가 증가할수록 자기저항은 감소하는 경향을 나타내지만, 그 밖의 설계인자들의 영향은 작게 나타났다. 상용해석프로그램을 이용하여 등가자기회로 결과와 비교를 하였으며, 대시포트 마운트를 제작하여 자극의 유효길이 변화에 대한 감쇠력의 변화를 실험적으로 비교하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.444-449
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• 2009

An engine is one of the most dominant noise and vibration sources in vehicle systems. Therefore, in order to resolve noise and vibration problems due to engine, various types of engine mounts have been proposed. This work presents a new type of active engine mount system featuring a magneto-rheological (MR) fluid and a piezostack actuator. As a first step, six degrees-of freedom dynamic model of an in-line four-cylinder engine which has three points mounting system is derived by considering the dynamic behaviors of MR mount and piezostack mount. In the configuration of engine mount system, two MR mounts are installed for vibration control of roll mode motion whose energy is very high in low frequency range, while one piezostack mount is installed for vibration control of bounce and pitch mode motion whose energy is relatively high in high frequency range. As a second step, linear quadratic regulator (LQR) controller is synthesized to actively control the imposed vibration. In order to demonstrate the effectiveness of the proposed active engine mount, vibration control performances are evaluated under various engine operating speeds (wide frequency range) and presented in time domain.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.6
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• pp.583-590
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• 2009

An engine is one of the most dominant noise and vibration sources in vehicle systems. Therefore, in order to resolve noise and vibration problems due to engine, various types of engine mounts have been proposed. This work presents a new type of active engine mount system featuring a magneto-rheological (MR) fluid and a piezostack actuator. As a first step, six degrees-of freedom dynamic model of an in-line four-cylinder engine which has three points mounting system is derived by considering the dynamic behaviors of MR mount and piezostack mount. In the configuration of engine mount system, two MR mounts are installed for vibration control of roll mode motion whose energy is very high in low frequency range, while one piezostack mount is installed for vibration control of bounce and pitch mode motion whose energy is relatively high in high frequency range. As a second step, linear quadratic regulator (LQR) controller is synthesized to actively control the imposed vibration. In order to demonstrate the effectiveness of the proposed active engine mount, vibration control performances are evaluated under various engine operating speeds(wide frequency range) and presented in time domain.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.43-51
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• 2014

Purpose : To review MR imaging finding of papillary lesion identified as additional suspicious lesion on MR image in women with biopsy-proven breast cancer and to evaluate upgrading rates after subsequent surgical histopathological diagnosis. Materials and Methods: Among 1729 preoperative MR image of women with biopsy proven breast cancer, US-guided CNB-proven 22 papillary lesions from 21 patients, which showed additional suspicious contrast enhancement other than index cancer on MR image, were subjected to the study. Some of these lesions underwent surgery, thus the comparisons between the histopathologic results were able to be compared to the results of US-guided CNB. Also retrospective analysis was done for MR findings of these lesions by BI-RADS MRI lexicon. Results: On MR imaging, 8 mass lesions, 7 non-mass lesions, 7 focus lesions were detected. All of the focus lesion (100%, 7/7) was diagnosed as benign lesion and showed plateau and washout pattern in dynamic MR image. After excisional biopsy, one of 9 benign papilloma (11.1%), 3 of 3 papillary neoplasm with atypia component (100%), 3 of 5 papillary neoplasm (60%) were upgraded to malignancy such as ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC). Conclusion: The MR images of papillary lesions diagnosed by US-guided CNB exhibit no significant differences between malignancy and benign lesion. Also 41.2% of the lesion (7/17) was upgraded after subsequent surgery. Thus all of the papillary lesions require excisional biopsy for definite diagnosis and the MR imaging, it's just not enough by itself.