• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.1043-1052
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• 2009

In this work, a master-slave manipulator system which will be used for handling objects contaminated by radioactivity has been addressed. The links of manipulators are driven independently by individual motors installed on the base and the driving torque is transmitted through pre-tensioned tendons. Since the measurable variables are the positions and rates of master/slave motors, only a constrained specific bilateral control structure is available. In the consideration of the flexibility of the tendon and constrained control structure, we derived a necessity for tendon design to prevent uncontrollable vibration mode through a modal analysis. Based on a reduced rigid body model, a control design was suggested and tendons were selected. The feasibility of the proposed analysis and tendon design were verified along with some simulation results.

• The Journal of Korea Robotics Society
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• v.9 no.3
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• pp.178-184
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• 2014

Tendon driven robot mechanisms have many advantages such as allowing miniaturization and light-weight designs and/or enhancing flexibility in the design of structures. When designing or analyzing tendon driven mechanisms, it is important to determine how the tendons should be connected and whether the designed mechanism is easily controllable. Graph representation is useful to view and analyze such tendon driven mechanisms that are complicatedly interconnected between mechanical elements. In this paper, we propose a method of generalized graph representation that provides us with an intuitive analysis tool not only for tendon driven manipulators, but also various other kinds of mechanical systems which are combined with tendons. This method leads us to easily obtain structure matrix - which is the one of the most important steps in analyzing tendon driven mechanisms.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.135-143
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• 2016

In this paper, a design concept of post-tensioned precast bridge piers was proposed to improve seismic behavior of the bridge pier. Mild reinforcing bars are placed continuously along the height of the column. Prestressing tendons are also provided to obtain re-centering capability for seismic events. Arrangement of the axial steels to prevent buckling of rebars at plastic hinge region was suggested and enhanced seismic performance was verified by experiments. Moment-curvature analyses were performed to evaluate the effect of effective prestress on seismic behavior after verifying the calculation method by cyclic tests of the precast columns. A real bridge pier was designed to investigate the seismic performance according to different level of effective prestress. Level of effective prestress showed obvious effect on crushing displacement but negligible effect on lateral displacement at fracture of tendons and reinforcements.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.381-386
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• 1999

The member with external unbonded tendon has two remarkable characteristics, i.e., eccentricity variation and slip by friction force at deviators, compared with internal bonded or unbonded member. An efficient numerical procedure for the nonlinear analysis of prestressed concrete beam with external unbonded tendon considering two remarkable characteristics is formulated and corresponding computer code is developed. On the basis of statistical process of parametric study results, strain compatibility method, eccentricity variation predictor and tendon stress predictor at ultimate state are proposed and verified with test results and existing Codes, which can evaluate flexural behavior at ultimate state. Finally, the proposed procedure and predictors can be efficiently used for the realistic and accurate analysis of prestressed concrete members with external unbonded tendons.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.315-318
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• 2005

Vlasov's hypothesis provides a way to solve the torsional problem with warping torsion of double T-beam section. Not only the warping torsion of the gross section of double T-beam but the torsional resistances of PS tendons and reinforcements have to be considered together in the analysis in which the latter is the restoring roles provided by the upward and downward force components in a geometrical symmetric configuration. It means that the torsional resistances of PS tendons and reinforcements, usually ignored, store the strain energies due to up-downward geometrical changes. Space frame element with 7-degrees of freedom are used for the finite element approximation of the real behaviors. Bimoments and angles of twist obtained from the proposed method show good agreements with those of 3-D. finite element analysis and analytical analysis

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.363-366
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• 2003

This study is to develop a strengthening method for RC slab bridges and rigid-frame bridges with external prestressing. In this study, we design the slab specimen that have a strengthening of the DB-13 and set up the longitudinal tendons placed on both side of slab strengthens the whole bridge, and lateral tendons placed under the slab strengthens the middle of slab, and conveys the load at middle slab to both sides. Structural analysis for the tensile force for strengthening were analysed and we know that displacement and strain was improved from this test. This method has no upward roof work, so it is very convenient for installing. And no spaces under the slab are need, so it is good for shallow slabs which has less space inder the slab.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.81-85
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• 1997

This article describes a modified arthroscopic technique of anterior cruciate ligament (ACL) reconstruction using quadrupled hamstring tendon graft. The autogenous semitendinosus and gracilis grafts are harvested without detachment of the tibial insertion. To obtain longer graft, the accessory tibial insertions of the hamstring tendons are dissected. The EndoButton(Acupex Microsurgical, Andover, MA) is used for femoral fixation and two spiked staples are used for tibial fixation in a belt buckle fashion. Then the residual anterior laxity is restored by additional absorbable interference screw fixations. In this technique. more viable graft is obtained and firmer distal fixation is achieved by preservation of the tibial insertion of hamstring tendons.

• Journal of Korean Foot and Ankle Society
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• v.20 no.1
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• pp.46-49
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• 2016

Spontaneous rupture of the extensor tendon has been reported in association with predisposing inflammatory conditions including rheumatoid arthritis, diabetes, trauma, tophaceous gout, and steroid injection. The authors experienced a case of spontaneous rupture of the extensor digitorum longus tendons caused by an osteophyte of the tarsometatarsal joint in a patient with rheumatoid arthritis. The authors stress that aggressive treatment including surgery could be considered for prevention of spontaneous tendon rupture in a patient with predisposing conditions despite an asymptomatic spur.

• The Journal of Korean Physical Therapy
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• v.14 no.3
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• pp.145-173
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• 2002

This study was performed to investigate the effect of ultrasound irradiation on $TGF-\beta_1$ expression in the surgically injured achilles tendons of rats. The results of this study were as following: 1. The control group (3 days after injury) expressed little immunoreactivity for $TGF-\beta_1$. 2. In the experimental groups, $TGF-\beta_1$ immunoreactivity of group 11(applied US for 3 days) was increased markedly than that of group 1(applied US for 1 day). 3, The experimental group 11(applied US for 3 days) expressed higher immunoreactivity for $TGF-\beta_1$ than control group. These findings suggest that ultrasound irradiation on the injured Achilles tendon may be of benefit such as increasing $TGF-\beta$ release in the inflammatory phase of heal ins process.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1297-1302
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• 2000

A literature review has been carried out to investigate why bridges have collapsed without warning. The reasons behind the collapses have been categorized into short and long term risks. It is thought that permanent monitoring systems which assess structural adequacy are more appropriate to long term risks. From the knowledge of the Korean bridge stock, its current problems and its likely future problems, it was considered that generally the most useful application for a permanent monitoring system is to monitor where chloride-induced corrosion either of the reinforcement or prestressing tendons is possible. A number of permanent monitoring systems currently in use on existing bridges which include some aspect of corrosion detection have been reviewed. The reasons as to why they are being used, what is being measured, what techniques are being used, and if they are deemed successful has been investigated. Based on these findings, and experimental programme has been constructed to investigate the accuracy, reliability and usefulness of various suitable techniques which could be included in a permanent monitoring system.