• International Journal of Automotive Technology
• /
• v.7 no.5
• /
• pp.579-584
• /
• 2006

Aluminum Resistance Spot Weld(Al RSW) is an enabling technology for body assembly of low mass fraction vehicles. Due to the unreliable durability of spot-welded joints, applications of Al RSW are limited. This study presents experimental investigation on the use of a post-weld cold working process to improve the fatigue strength of Al RSW. The post-weld cold working process includes special shaped indenters that are pressed or driven into the structure to induce compressive residual stresses. The mechanical properties of the post-weld cold worked Al RSW were investigated, including the experimental results of fatigue and micro-hardness tests. Comparisons of the mechanical properties and qualitative results between the as-welded RSW specimens and the post-weld cold worked RSW specimens are discussed. The post-weld cold worked Al RSW samples had an increase in both microhardness and fatigue life.

• Journal of Korean Physical Therapy Science
• /
• v.4 no.2
• /
• pp.373-382
• /
• 1997

This study has been aimed at figuring out the fact that four kinds of body type grouped according to the tilting of scapular of upper extremity and ilium of low extremity showed the mobility increase for joint parts and the limitation. When we make a thrapy plan which should be comprehensive and general in preventative management and therapy. For the sake of patients who have spinal disabilities including low back pains, it is required for many joints distributing among upper and lower extremity to have hypermobility and hypomobility based on regulation. So, this study was conducted to establish a standard for the effective pattern of hypermobility or hypomobility. I hope that the result of this study can help support the practics of physical therapy as a part of scientic method. Especially I think it will be able to be conductive to those who major in physical therapy on the arthrogenic region.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1995.04a
• /
• pp.787-796
• /
• 1995

A man model is a useful design tool for the evaluation of man machine systems and products. An arm reach trajectory prediction for such a model will be specifically useful to present human activities and, consequently, could increase the accuracy and reality of the evaluation. In this study, a three-dimensional reach trajectory prediction model was developed using an inverse kinematics technique. The upper body was modeled as a four link open kinematic chain with seven degrees of freedom. The Resolved Motion Method used for the robot kinematics problem was used to predict the joint movements. The cost function of the perceived discomfort developed using the central composite design was also used as a performance function. This model predicts the posture by moving the joints to minimize the discomfort on the constraint of the end effector velocity directed to a target point. The results of the pairwise t-test showed that all the joint coordinates except the shoulder joint's showed statistically no differences at .alpha. = 0.01. The reach trajectory prediction model developed in this study was found to accurately simulate human arm reach trajectory and the model will help understand the human arm reach movement.

• Journal of the Korean Society for Railway
• /
• v.2 no.2
• /
• pp.13-20
• /
• 1999

The vibration signals of driving parts of electric train are distorted its signal patterns due to the impact components, which occurs when wheel passes rail joints. An elimination method of the impact components is investigated using adaptive signal processing technique in this study The result shows that adaptive interference canceling method seems to be more effective than line enhancement technique. The application of adaptive interference canceling method to the signal measured at bogie shows that the extractions of the signals of driving parts of traction motor, reduction gear, and axle bearing are successful. Therefore, only the signals of bogie, which is the place to attach an accelerometer easily, is sufficient for the fault diagnosis and the safety evaluation of electric train. Also, adaptive interference canceling method can be applicable to evaluate the performance of vibration isolation between bogie and car body and to investigate the characteristics of indoor sound.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.83-83
• /
• 2001

Head of Panax ginseng indicates its growth number of years and it has been widely used for supplying energy to weak person. However, the underlying mechanisms are not sufficiently reported. Thus, we inclined to study head of Panax ginseng in rheumatoid arthritis and inflammation. Rheumatoid arthritis (RA), an organ-specific inflammatory disease of human, is characterized by a chronic and destructive inflammatory reaction and possibly autoimmune in etiology. It is occurred when the synobial membranes of joints and many other tissues of the body is attacked which induces significant health problem in terms of numbers of sufferers (U.S. incidence 23.7/100,000), and the synobial inflammatory is dominated by activated macrophage.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1288-1293
• /
• 2003

This study predicts muscle forces acting on the lower extremity when the knee joint is in deep flexion. The whole bodies were approximated as a link model, and then the moment equilibrium equations at the lower extremity joints were derived for given reaction forces against the ground. Measurement of deep flexion was carried out by placing ten markers on the body. This study calculated the moment acting at each joint from the equations of force and moment, classified the complicated muscles around the knee joint. and then predicted the muscle forces to balance the joint moment. Two models were proposed in this study: the simpler one that consists of three groups of muscle and the more detailed one of nine groups of muscle.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.583-586
• /
• 2000

The conventional actuators with the speed reducer had weakness in supporting the weight of the body and leg itself. To overcome this, a new four bar link mechanism actuated by the ball screw was proposed. The four bar mechanism has higher strength and gear ratio than the conventional actuator to actutate the leg of the biped robot. One leg was designed to have ankle, thigh, and hip joints. The kinematics and dynamics of one leg with four bar link mechanism was analyzed using Euler-Lagrange approach. The dynamics of one leg was expressed in the ball strew frame.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.616-617
• /
• 2013

This paper introduces a new method that controls a humanoid robot detecting a human motion using a Kinect sensor. Processing the output of a depth seneor of the Kinect sensor, we build a human stick model which represents each joint of human body. We detect a specific motion by calculating the distance and angle between joints. We send the control message to the robot using Bluetooth wireless communication.

• Journal of Korean Institute of Industrial Engineers
• /
• v.11 no.2
• /
• pp.87-99
• /
• 1985

The purpose of this study is to analyze the changes in centers-of-gravity (COG), acceleration and body posture and their associated effects both on EMG and on the maximum capability of weight lifting during Clean & Jerk and Snatch motions. Displacement, velocity, acceleration of joints were obtained from film analysis. Also levels of exertions on 11 major muscle groups were obtained from EMG analysis during a lifting cycle. The EMG data were measured from Telemetry System which is useful in field experiments. Magnitude and direction of force, change in center-of-gravity were extracted from COG data which were measured from force platform. The results of this study can be to be useful both to coaches and to athletes in weight-lifting.

• Journal of Power System Engineering
• /
• v.5 no.1
• /
• pp.80-88
• /
• 2001

The spot welding method has been used in the joining of structures, automotive body, railway carriage, aircraft, household electric appliances, precision parts etc., because of brief working, easy automation, available mass production, and convenience. In this paper, the effects of welding conditions on the fatigue life and the prediction of fatigue life based on fracture mechanics theory of spot welded joint were investigated. Fatigue tests were conducted with the tensile-shear specimens welded in the various current using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. Using FEM(finite element method), we analysed the distribution of stress and the condition of deformation on the environments of nugget.