• International Journal of Highway Engineering
• /
• v.13 no.4
• /
• pp.93-101
• /
• 2011

The evaluation of various color coating methods for color maintenance of color asphalt pavement is conducted using the laboratory and field tests on the bus lane. The surface of color asphalt constructed on the bus lane is deteriorated such as changing color and decoloration and abrasion due to the passing of the traffic and time. The total of 9 coating methods were evaluated in this study. The laboratory tests included Ultra violet test, adhesion test and Taber abrasion test and the field tests were british pendulum test and visual survey. The results of tests showed that the different methods showed the their own engineering characteristics and it is dependant upon the main material used. The rubber epoxy material for the main material showed the satisfactory result among the methods tested. However, the performance of the coating methods after 100days are not satisfactory, decoloration, abrasion and peeling up are investigated and need to be studied for the further application in the field.

• Journal of Biomedical Engineering Research
• /
• v.21 no.3 s.61
• /
• pp.303-309
• /
• 2000

An accurate quantitative biomechanical evaluation for the spasticity caused by the disorder of central nervous system was made in this study. A sudden leg dropper was designed to generate objective testing environment at every trial. 3-dimensional motion analysis system(Elite. B.T.S. Italy) was used to measure kinematic data which were angle. and angular velocity of a lower limb. A program was developed to analyze the kinematic data of lower limb motion. and dynamic EMG data at the same time. To evaluate spasticity quantitatively. total 26 parameters including 14 parameters newly driven were analyzed, and statistical analysis were made for bilateral correlations. Results showed possibility to make accurate quantitative and objective evaluation for spasticity with various new parameters using new devices and program.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.2
• /
• pp.105-112
• /
• 2023

In this study, structural analyses were conducted to analyze the performance of a bridge to which friction pendulum systems (FPSs) were applied using different friction models. A Coulomb friction model and a rate dependent friction model were constructed using the friction coefficient of a PVDF/MgO friction material to analyze the effect of different friction analysis models. The Coulomb friction model uses a single friction coefficient regardless of friction velocity, while the rate dependent friction model can reflect the change in the friction coefficient with friction velocity. Nonlinear time history and seismic fragility analyses were conducted to confirm responses of the bridge. The seismic responses of a deck and a column were used to evaluate the performance of the base isolated bridge, and a friction model that can effectively evaluate the performance of isolated bridges was analyzed.

• Tunnel and Underground Space
• /
• v.32 no.6
• /
• pp.451-463
• /
• 2022

Whenever a mineshaft accidentally collapses, speedy risk assessment is both required and crucial. But onsite safety diagnosis by humans is reportedly difficult considering the additional risk of collapse of the unstable mineshaft. Generally, drones equipped with high-speed lidar sensors can be used for such inspection. However, the drone technology is restrictively applicable at very shallow depth, failing in mineshafts with depths of hundreds of meters because of the limit of wireless communication and turbulence inside the mineshaft. In previous study, a three-dimensional (3D) scanning system with a single channel lidar was fabricated and operated using towed cable in a mineshaft to a depth of 200 m. The rotation and pendulum movement errors of the measuring unit were compensated for by applying the data of inertial measuring unit and comparing the similarity between the scan data of the adjacent depths (Kim et al., 2020). However, the errors grew with scan depth. In this paper, a multi-channel lidar sensor to obtain a continuous cross-sectional image of the mineshaft from a winch system pulled from bottom upward. In this new approach, within overlapped region viewed by the multi-channel lidar, rotation error was compensated for by comparing the similarity between the scan data at the same depth. The fabricated system was applied to scan 0-165 m depth of the mineshaft with 180 m depth. The reconstructed image was depicted in a 3D graph for interpretation.