• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.237-244
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• 2019

This paper suggests novel types of joint mechanisms composed of elastic strings and rigid bodies. All of the human hinge joints have the articular capsule and a pair of collateral ligaments. These fibrous tissues make the joint compliant and stable. The proposed mechanism closely imitates the human hinge joint structure by using the concept of tensegrity. The resultant mechanism has several characteristics shown commonly from both the tensegrity structure and the human joint such as compliance, stability, lightweight, and non-contact between rigid bodies. In addition, the role and feature of the human hinge joints vary according to the origins of a pair of collateral ligaments. Likewise, the locations of two strings corresponding to a pair of collateral ligaments produce different function and motion of the proposed mechanism. It would be one of the advantages obtained from the proposed mechanism. How to make a joint mechanism with different features is also suggested in this paper.

• PNF and Movement
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• v.6 no.1
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• pp.53-60
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• 2008

Purpose : To describes the important aspects of knee joint movement and function used when applying PNF technique to the lower limb. Method : The knee was a very important roles in the lower limb movement and ambulation. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The tibiofemoral joint is usually described as a modified hinge joint with flexion-extension and axial rotation by two degrees of freedom movement. These arthrokinematics are a result of the geometry of the joints and the tension produced in the ligamentous structures. The patellofemoral joint is a sellar joint between the patella and the femur. Stability of the patellofemoral joint is dependent on the passive and dynamic restraints around the knee. In a normal knee the ligaments are inelastic and maintain a constant length as the knee flexes and extends, helping to control rolling, gliding and translation of the joint motions. Conclusions : It is important to remember that small alterations in joint alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Successful treatment requires the physical therapist to understand and apply these arthrokinematic concepts. When applied to PNF low extremity patterns, understanding of these mechanical concepts can maximize patient function while minimizing the risk for further symptoms or injury.

• Structural Engineering and Mechanics
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• v.54 no.1
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• pp.121-133
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• 2015

The aluminum dome has been widely used in natatorium, oil storage tank, power plant, coal, as well as other industrial buildings and structures. However, few research has focused on the structural behavior and design method of this dome. At present, most designs of aluminum alloy domes have referred to theories and methods of steel spatial structures. However, aluminum domes and steel domes have many differences, such as elasticity moduli, roof structures, and joint rigidities, which make the design and analysis method of steel spatial structures not fully suitable for aluminum alloy dome structures. In this study, a stability analysis method, which can consider structural imperfection, member initial curvature, semi-rigid joint, and skin effect, was presented and used to study the stability behavior of aluminum dome structures. In addition, some meaningful conclusions were obtained, which could be used in future designs and analyses of aluminum domes.

• Structural Engineering and Mechanics
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• v.24 no.5
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• pp.585-599
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• 2006

This paper describes a series of laboratory tests carried out to evaluate the influence of bed joint orientation on interlocking grouted stabilised mud-flyash brick masonry under uniaxial cyclic compressive loading. Five cases of loading at $0^{\circ}$, $22.5^{\circ}$, $45^{\circ}$, $67.5^{\circ}$ and $90^{\circ}$ with the bed joints were considered. The brick units and masonry system developed by Prof. S.N. Sinha were used in present investigation. Eighteen specimens of size $500mm{\times}100mm{\times}700mm$ and twenty seven specimens of size $500mm{\times}100mm{\times}500mm$ were tested. The envelope stress-strain curve, common point curve and stability point curve were established for all five cases of loading with respect to bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. Also, the stability point curve has been used to define the permissible stress level in the brick masonry.

• Earthquakes and Structures
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• v.23 no.6
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• pp.535-547
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• 2022

Handball sport, as its name postulates, is a team sport which highly physical workout. During a handball play, several ball impacts are applied on the hands resulting vibration in the forearm, upper arm, shoulders and in general in whole body. Hand has important role in the handball's game. So, understanding about the dynamics and some issues that improve the stability of the hand is important in the sport engineering field. Ulna and radius are two parallel bones in lower arm of human hand which their ends are located in elbow and wrist joint. The type of the joint provides the capability of rotation of the lower arm. These two bones with their ends conditions in the joints constructs a 4-link frame. The ulna is slightly thinner than radius. So, understanding about hand kinematics in handball's game is an important thing in the engineering field. So, in the current work with the aid of a multi-physics simulation, dynamic stability analysis of the ulna and radius bones will be presented in detail.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.821-828
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• 2011

Purpose: The authors applied Bilhaut-Cloquet procedure to Wassel type III and IV duplicated thumb, which was limited to patients with Wassel type I, II. This procedure was applied in order to improve the growth potential, range of joint motion, joint stability and cosmetic outcome. Methods: Sixteen patients received Bilhaut-Cloquet procedures to correct duplicated thumbs from May, 2005 to December, 2010. Seven patients were Wassel type III, nine patients were type IV. This procedure was applied not only to balanced type, but also unbalanced type or convergent type. Five patients were balanced type and eleven patients were unbalanced type. Convergent type of Wassel type IV was three. Sex ratio was the same, mean age at the operation was 20.1 months old (8~52 months old). Angular deformity, joint stability and range of joint motion and cosmetic outcome were considered together and estimated in Tada score. Also, postoperative subjective satisfaction score of the parents was evaluated by a 100-points scale. Results: Mean subjective satisfaction scored 75 points at 28 months after the operation. Radiologic study showed bony union of proximal phalangeal bone and stable joint in all patients. Range of motion was mean 20 degrees in interphalangeal joint and mean 73 degrees in metacarpophalangeal joint. Tada score showed 'good' in eleven patients (68.8%), 'fair' in three patients (18.7%) and 'poor' in two patients (12.5%). In seven patients those who were able to follow up for a long term showed no significant difference in length of proximal and distal phalangeal bones compared to the opposite thumb. Conclusion: Bilhaut-Cloquet procedure can be applied not only to balanced type of Wassel type III, IV duplicated thumb, but also to unbalanced type or convergent type that focused on functional reconstruction and cosmetic improvement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.1 s.94
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• pp.3-11
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• 2005

For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplexibility in one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability and dominate the strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.

• Journal of Welding and Joining
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• v.25 no.1
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• pp.57-62
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• 2007

In the coarse grained HAZ of conventional TiN steel, most TiN particles are dissolved and austenite grain growth easily occurrs during high heat input welding. To avoid this difficulty, thermal stability of TiN particles is improved by increasing nitrogen content in EH36-TM steel. Increased thermal stability of TiN particle is helpful for preventing austenite grain growth by the pinning effect. In this study, the mechanical properties and microstructures of high heat input welded Tandem EGW joint in EH36-TM steel with high nitrogen content were investigated. The austenite grain size in simulated HAZ of the steel at $1400^{\circ}C$ was much smaller than that of conventional TiN steel. Even for high heat input welding, the microstructure of coarse grained HAZ consisted of fine ferrite and pearlite and the mechanical properties of the joint were sufficient to meet all the requirements specified in classification rule.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.595-601
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• 2003

For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplicity of one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability und dominate tile strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.1
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• pp.32-43
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• 1999

Adaptive robust control scheme is introduced for flexible joint manipulator with nonlinearities and uncertainties. The system does not satisfy the matching condition due to insufficient actuators for each node. The control only relies on the assumption that the bound of uncertainty exists. Thus, the bounded value does not need to be known a prior. The control utilizes the update law by estimating the bound of the uncertainties. The control scheme uses the backstepping method and constructs a state transformation. Also, stability analysis is done for both transformed system and original system.