• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.799-802
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• 1997

This paper deals with a new method to derive the Generalized Jacobian Matrix of a space robot. In a conventional method to derive the Generalized Jacobian Matrix, generalized coordinates select Joint angles and a space robot body's position and attitude angle. But, in this paper, we select position and attitude angle of the end-effector or the handled floating object as generalized coordinates. Then, we can derive the Generalized Jacobian Matrix of the system which consists of several space robots and a handled floating object. Moreover control methods operated by only one space robot can be easily extended to the cases of cooperation task by several space robots. Computer simulations show that the Generalized Jacobian Matrix derived here is effective.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.1-8
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• 2001

This study was designed to localize the distribution of basic fibroblast growth factor(bFGF) in the developing rat condylar region and to elucidate the associated function of bFGF in the condyle development. The condyles of temporomandibular joint of Sprague-Dawley rats (27g of weight) were used. The tissues were examined with electron microscope and immunohistochemical method. The results were as follows: 1. The developing condylar region are divided in to 5 zones apparently: proliferative, maturation, hypertrophic, calcifying, and ossification zones. 2. The cells in the proliferative zone are condensed and have under-developed cell organells in the cytoplasm. This zone shows a strong immunoreactivity of bFGF. 3. The cells in the maturation zone are typical chondroblasts showing well-developed cell organells and round nucleus. The cartilaginous matrix does not show the immunoreactivity of bFGF, while the chondroblasts show the immunoreactivity. 4. The cells in the hypertrophic zone show hypertrophic change having the degenerated cell organelles and small nucleus. There are no immunoreactivity of bFGF in this zone except the nucleus and endoplasmic region showing mild immunoreactivity. 5, The cells in the calcifying zone show hypertrophic change and cell organelles are disappeared. The cells are surrounded by the calcified cartilaginous matrix. There are no immunoreactivity of bFGF in this zone except the endoplasmic region showing mild immunoreactivity. 6. In the zone of bone formation, chondroblasts are disappeared. Newly differentiated osteoblasts secreting osteoid around the calcified cartilaginous matrix. The bone marrow shows the immunoreactivity of bFGF, while the bone matrix does not show the immunoreactivity of bFGF.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.54-60
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• 2015

Background: The present study was designed to prepare and find the optimum active preparation or fraction from Korea Red Ginseng inhibiting matrix metalloproteinase-13 (MMP-13) expression, because MMP-13 is a pivotal enzyme to degrade the collagen matrix of the joint cartilage. Methods: From total red ginseng ethanol extract, n-BuOH fraction (total ginsenoside-enriched fraction), ginsenoside diol-type-enriched fraction (GDF), and ginsenoside triol-type-enriched fraction (GTF) were prepared, and ginsenoside diol type-/F4-enriched fraction (GDF/F4) was obtained from Panax ginseng leaf extract. Results: The n-BuOH fraction, GDF, and GDF/F4 clearly inhibited MMP-13 expression compared to interleukin-$1{\beta}$-treated SW1353 cells (human chondrosarcoma), whereas the total extract and ginsenoside diol-type-enriched fraction did not. In particular, GDF/F4, the most effective inhibitor, blocked the activation of p38 mitogen-activated protein kinase (p38 MAPK), c-Jun-activated protein kinase (JNK), and signal transducer and activator of transcription-1/2 (STAT-1/2) among the signal transcription pathways involved. Further, GDF/F4 also inhibited the glycosaminoglycan release from interleukin-$1{\alpha}$-treated rabbit cartilage culture (30.6% inhibition at $30{\mu}g/mL$). Conclusion: Some preparations from Korean Red Ginseng and ginseng leaves, particularly GDF/F4, may possess the protective activity against cartilage degradation in joint disorders, and may have potential as new therapeutic agents.

• Journal of the Korean Arthroscopy Society
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• v.11 no.1
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• pp.1-6
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• 2007

Purpose: The purpose of this preliminary report is to investigate the short term outcome of performing gel type fibrin matrix autologous chondrocyte implantation to patients who have damaged knee joint cartilage using secondary arthroscopy. Material and Methods: Six patients who have damaged knee joint cartilage were involved. The average size of defect was $5.13\;cm^2$. While performing primary arthroscopy, whole layer of cartilage bone was obtained either from the margin of damaged cartilage or the bilateral margin of a trochlea. The cartilaginous cells were obtained for culture for four to six weeks. While performing secondary minimal invasive arthrotomy, gel type fibrin matrix autologous chondrocyte was implanted on the chondral defect site. Results: 4 among 6 patients to be more than good in Modified Cincinnati Knee Scoring system. Lysholm function score was 59.5 preoperatively, and it improved to 76.25. ICRS grading by performing secondary arthroscopy revealed 4 out of 6 patients to be nearly normal. Conclusion: Gel type fibrin matrix autologous chondrocyte implantation is a treatment for cartilage defect, which takes less time to operate than the conventional implantation. In addition, this method minimizes the size of incision and allows arthroscopic surgery. However, long term follow up and more case study is thought to be necessary.

• Tunnel and Underground Space
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• v.9 no.1
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• pp.1-11
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• 1999

A finite element code was developed to analyze coupled thermo-hydro-mechanical phenomena. This code is based on the finite element formulation provided by Noorishad et al. (1984) and Joint behavior was simulated Goodman's joint constitutive model. The developed code was applied for T-H-M coupling analysis for two kinds of shaft models, with a joint or without a joint respectively. For a model without a joint, temperature increased from the shaft wall to outward evidently. The radial displacement showed opposite directions of outward and inward at some distance from shaft wall. For a model with a joint, closure of joint was found due to thermal expansion. The temperature distribution along a joint showed relatively lower than that of rock matrix because of low thermal conductivity and high specific heat of water. And it could be concluded that effects of thermal flow to joint were more than that of hydraulic flow in a rock mass.

• Journal of Welding and Joining
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• v.31 no.3
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• pp.4-10
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• 2013

In electronic industry, the trend of future electronics will be flexible, bendable, wearable electronics. Until now, there is few study on bonding technology and reliability of bonding joint between chip with micro solder bump and flexible substrate. In this study, we investigated joint properties of Si chip with eutectic Sn-58Bi solder bump on Cu pillar bump bonded on flexible substrate finished with ENIG by flip chip process. After flip chip bonding, we observed microstructure of bump joint by SEM and then evaluated properties of bump joint by die shear test, thermal shock test, and bending test. After thermal shock test, we observed that crack initiated between $Cu_6Sn_5IMC$ and Sn-Bi solder and then propagated within Sn-Bi solder and/or interface between IMC and solder. On the other hands, We observed that fracture propated at interface between Ni3Sn4 IMC and solder and/or in solder matrix after bending test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.756-765
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• 2001

An effective dexterous motion control method of redundant robot manipulators based on neural optimization network is proposed to satisfy multi-criteria such as singularity avoidance, minimizing energy consumption, and avoiding physical limits of actuator, while performing a given task. The method employs a neural optimization network with parallel processing capability, where only a simple geometric analysis for resolved motion of each joint is required instead of computing of the Jacobian and its pseudo inverse matrix. For dexterous motion, a joint geometric manipulability measure(JGMM) is proposed. JGMM evaluates a contribution of each joint differential motion in enlarging the length of the shortest axis among principal axes of the manipulability ellipsoid volume approximately obtained by a geometric analysis. Redundant robot manipulators is then controlled by neural optimization networks in such a way that 1) linear combination of the resolved motion by each joint differential motion should be equal to the desired velocity, 2) physical limits of joints are not violated, and 3) weighted sum of the square of each differential joint motion is minimized where weightings are adjusted by JGMM. To show the validity of the proposed method, several numerical examples are illustrated.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.123-128
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• 1996

Kinematically redundant manipulators have been studied because of its usefulness of kinematic redundancy. It is natural that the kinematic redundancy induces a kind of control redundancy. By using the weighted kinematically decoupled joint space decomposition, we unify the control redundancy and the kinematic redundancy parameterized by the joint space weighting matrix. Concentrating to the particular component of each decomposition, we can describe the local minimization behavior of the control weighted quadratic by each weighted decomposition. The result extends the conventional results on general setting, and should be of interest in understanding the motion behavior of kinematically redundant manipulators.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.573-576
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• 1996

We propose robust control scheme for flexible joint manipulator in the presence of nonlinearity and mismatched uncertainty. The control is designed based on Lyapunov approach. The robust control which is based on the computed torque scheme and state transformation via implanted control is introduced. The design procedure starts with the construction of linearized subsystems via the computed torque method and then uses state transformation. With this approach we do not impose an upper-bound constraint on the inertia matrix in case it is known. Thus, this control can be applied to arbitrary manipulators. The resulting robust control guarantees practical stability for both the transformed system and the original system. The transformation is only based on the possible bound of uncertainty.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.1-6
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• 1992

A principle of "orthogonalization" is proposed as an extended notion of hybrid (force and position) control for robot manipulators under geometric endpoint constraints. The principle realizes the hybrid control in a strict sense by letting position and velocity feedback signals be orthogonal in joint space to the contact force vector whose components are exerted at corresponding joints. This orthogonalization is executed via a projection matrix computed in real-time from a gradient of the equation of the surface in joint coordinates and hence both projected position and velocity feedback signals become perpendicular to the force vector that is normal to the surface at the contact point in joint space. To show the important role of the principle in control of robot manipulators, three basic problems are analyzed, the first is a hybrid trajectory tracking problem by means of a "modified hybrid computed torque method", the second is a model-based adaptive control problem for robot manipulators under geometric endpoint constraints, and the third is an iterative learning control problem. It is shown that the passivity of residual error dynamics of robots follows from the orthogonalization principle and it plays a crucial role in convergence properties of both positional and force error signals.force error signals.