• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.81-86
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• 2015

We fabricated a 3D knee joint model through the imaging processing. The 3D shape information is different depends on specific conditions when the shape of real knee joint is extracted from CT/MRI sliced images. The two types of joint models were fabricated by using 3D printer in order to analysis of joint movement by slight difference of 3D shape information. The compressive force experiments were performed by using knee joint model. As the results, the compressive forces were changed with respect to the difference of geometry. Consequently, feasibility test should be performed before developing biomimetic bioreactor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.533-539
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• 2009

In this study, the femur, the tibia, the articular cartilage and the menisci are three dimensionally reconstructed using MR images of healthy knee joint in full extension of 26-year-old male. Three dimensional finite element model of the knee joint is fabricated on the reconstructed model. Also, the FE models of ligaments and tendons are attached on the biologically suitable position of the FE model. Bones, articular cartilages and menisci are considered as homogeneous, isotropic and linear elastic materials, and ligaments and tendons are modeled as truss element and nonlinear elastic springs. The numerical results show the contact pressure and the von Mises stress distribution in the soft tissues such as articular cartilages and menisci which can be regarded as important parameters to estimate the failure of the tissues and the pain of the patients.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1397-1398
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• 2013

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.73-74
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• 2020

사용자 동작 추정이란 이미지 또는 비디오에서 사용자의 관절 위치를 추정하는 과정을 말한다. 기존의 연구들은 사용자의 몸에서 관절의 큰 부분(어깨, 무릎, 골반, 손, 발 등)만을 추정하거나 손의 세부 관절을 별도로 추정 했다. 하지만 특정 분야(수화, 댄스 등)에선 몸짓과 손을 함께 사용하기에 우리는 사용자 몸의 큰 관절과 손의 세부 관절을 같이 추정하는 방법에 대한 연구를 제안한다. 본 논문에서 제안하는 사용자 동작 추정 방법은 Cascades 방법을 이용한 합성곱 신경망 기반 회귀모델을 적용한 방식이다. 손의 관절들은 다른 큰 관절들(어깨, 무릎, 골반 등)보다 작아서 정밀한 추정을 요구하기에 Cascades 방법을 사용해 보다 정밀하게 추정할 수 있다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.1093-1098
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• 2002

본 연구실에서 개발한 MIMIC(Motion Interface & Motion Information Capture system)은 동작자의 동작을 획득하고, 동작의 의미를 이해할 수 있도록 설계된 시스템이다. 비전 센서로부터 입력된 영상을 분석하여 동작자의 머리와 두 손, 두 발의 정보를 찾는다. 그리고, 이 정보를 기반으로 팔꿈치나 무릎 등의 중간 관절을 추정한 후 20개의 관절을 가지는 3차원 인체 모델을 구성한다. 이 인체 모델은 동작자의 동작을 실시간으로 흉내낸다. 그러므로, 기존의 마커프리 모션캡쳐 시스템과 달리 완벽한 인체를 구성하기 위한 중간 관절까지 생성함으로써 동작자의 동작을 더욱 자연스럽게 구현할 수 있다.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.325-330
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• 2007

This study was to determine whether canine model which produce acute permanent joint instability in short period without postoperative exercise have a degenerative changes and also evaluated its suitability as an appropriate animal OA models. Ten skeletally mature beagle dogs underwent a unilateral surgical transection of the cranial cruciate ligament and, the medial collateral ligament as well as a medial meniscectomy. The contra-lateral joint was used as control. After 12 weeks, After 12 weeks, the amount of joint damage, inflammation and biochemical change of synovial fluid was evaluated. Histological analysis showed chondrocyte clone formation, hypertrophy of the cartilage and moderate loss of proteoglycans in the experimental joints compared to control joints. In addition, the synovial inflammation in the experimental joints was observed. Biochemical analysis of SF showed significantly increased MMP (matrix metalloproteinase) -2 and -9 in experimental joints compared to control joints. This canine OA model shows the characteristics of degenerative joint disease, and may have a advantages of reducing the time and cost because postoperative exercise is not needed in this OA model.

• Journal of the Korea Convergence Society
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• v.5 no.2
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• pp.7-11
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• 2014

The artificial joint is consisted with the upper structure of tungsten alloy steel and the lower part of polyethelene are applied with load. When this joint is applied with load in this study, the load distribution at the joint and the stress distribution of support hole to install the joint are investigated by finite element analysis. These results can be utilized at obtaining the basic material to have the experiment for the real thing. The crack is initiated as the load is concentrated at the end of corner on the upper structure. This behavior is in accord with a case of tissue damage due to the breakage of artificial joint reported at medical science.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.757-758
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• 2010

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1664-1671
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• 2004

It is necessary to have a model that describes the feature of the knee Joint with a sufficient accuracy. Koreans, however, do not have their own knee joint model to be used in the total knee replacement arthroplasty. They have to use European or American models which do not match Koreans. Three-dimensional visualization techniques are found to be useful in a wide range of medical applications. Three-dimensional imaging studies such as CT(computed tomography) and MRI(magnetic resonance image) provide the primary source of patient-specific data. Three-dimensional knee joint models were constructed by image processing of the CT data of 10 subjects. Using the constructed model, the dimensions of Korean knee joint were measured. And this study proposed a three-dimensional model and data, which can be helpful to develop Korean knee implants and to analyze knee joint movements.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.23-29
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• 2018

In knee implants, contact pressure has a significant effect on wear. In this study, finite element analysis is performed using the knee implant model developed in the previous research. The contact pressures for a total of 10 knee implant materials combinations were analyzed using the combinations actually used in research and industry. In order to calculate the contact pressure, The load was applied when the flection angle of knee was $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$. The result of contact pressure revealed the smallest contact pressure in the titanium alloy-UHMWPE combination. In the case of UHMWPE, contact pressure did not change much with any material used in the femur. Compared the combination with the largest contact pressure and the smallest contact pressure, the difference was 0.77%. On the other hand, Carbon / PEEK composites showed 5.3% difference when the contact pressure was the largest and the smallest. It can be seen that when the Carbon / PEEK composite material is used as the bearing part, the material of the femoral part affects the wear. This study will contribute to the prediction of knee implant wear and minimization of wear.