• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1198-1205
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• 2003

Most domestic fossil power plant have exceeded 100,000 hours of operation with the severe operating condition. Among the critical components of fossil power plant, high temperature steam pipe system have had a many problems and damage from unstable displacement behavior because of frequent start up and shut down. In order to prevent the serious damage and failure of the critical pipe system in fossil power plant, 3-dimensional displacement measurement system were developed for the on-line monitoring system. 3-D Measurement system was developed with using the LVDT type sensor and rotary encoder type sensor, this system was installed and operated on the real power plant successfully. In the future time, network system of on-line diagnosis for critical pipe will be designed.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.83-89
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• 2005

Most domestic fossil power plants have exceeded 100,000 hours of operation with the severe operating condition. Among the critical components of fossil power plant, high temperature steam pipe systems have had a many problems and damage from unstable displacement behavior because of frequent start up and shut down. In order to prevent the serious damage and failure of the critical pipe system in fossil power plants, 3-dimensional displacement measurement system was developed for the on-line monitoring. Displacement measurement system was developed with a use of a LVDT type sensor and two rotary encoder type sensors. This system was installed and operated on the real power plant successfully.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.431-432
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• 2008

In order to develop and inspect the electronic controller of propulsion system, It must emulate the electronic signal similar to actual signal. The applied signals on propulsion system are engine speed, turbine speed, various kinds of temperatue signal, pressure signal, LVDT/RVDT position signal and so forth. Contents are the development of emulator that simulate the electronic signals similar to actual signals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.180-180
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.375-376
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.127-130
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• 2004

For the quality control of the industrial products, an automatic hole measuring system has been developed. The measurement device allows X-Y movement due to contact forces between a hole and its own circular cone and the device is attached to an industrial robot. Its measurement accuracy is about 0.04mm. This movement of the plate is measured by two LVDT sensor system. But this system using the LVDT sensors is restricted by high cost and precision of measurement and correspondence of environment so particularly, a vision system with CCD-Camera is discussed in this paper for the above mentioned purpose. The device consists of two of two links jointed with hinge pins basically and, they guarantee free movement of the touch prove attached on the second link in the same plane. These links are returned to home position by the spring plungers automatically after each process for the next one. On the surface of the touch prove, it has a circular white mark for camera recognition. The system detect and notify the center coordinate of capture mark image through the image processing. Its measuring accuracy has been proved to be about $\pm$0.01mm through the repeated implementation over 200 times. This technique will shows the advantage of touch-indirect image capture idea using cone-shaped touch prove in various symmetrical shaped holes particulary, like tapped holes, chamfered holes, etc As a result, we attained our object in a view of the accuracy, economical efficiency, and functionality

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.353-360
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• 2014

The model ice is created at KRISO (Korea Research Institute for Ships and Ocean Engineering) ice basin where model ship is tested to obtain the necessary data in order to design the ice breaking vessels and ocean structures operating in the northern pole sea area. Through the model ship test, ice breaking, clearing, ice-ship and ice-propeller interaction behavior can be obtained. Since mechanical properties of ice plate are required for the model test, some tests are performed to obtain the properties in this paper. First, ultrasonic devide is used to measure the thickness of the model ice plate and the results show the possibility of using ultrasonic method, yet more sophisticated device or special sensors are required to measure the ice thickness completely. And the defection of ice plate is measured using LVDT to compute the characteristic length of ice plate on the fluid, which is used to get the effective Young's modulus of model ice.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.177-184
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• 2011

In this study, the system for application of the bone stimulation was implemented using high frequency and low strain method. The whole system consists of the high frequency and low strain vibration stimulation system 177 for stimulating bone, LVDT sensor, and wireless sensor based on tri-axial accelerometer. To evaluate the usefulness of the system, the frequencies and accelerations from function generator were applied to the vibration stimulation system. The range of frequency was 17 Hz, 30 Hz, 45 Hz, 50 Hz and the range of acceleration was set 0.3 g, 0.6 g, 1g, and 2 g. The measured frequencies and acceleration using LVDT (linear variable difference transformer) sensor and 3-axial accelerometer were estimated and compared. The range of frequencies average difference was from 0.0 to 0.004 Hz. As the standard deviation of frequencies estimated by LVDT sensor and accelerometer was below 0.03 Hz and the output frequencies of function generator were similar: Also the results of t-test were satisfied with conditions of p > 0.05. And the acquired frequencies and acceleration from vibration measuring device module were estimated and analyzed. As the mean of accelerations was similar to the acceleration applied from function generator. And the standard deviation of acceleration estimated from vibration measuring device module was ranged from 0.019 g to 0.038 g. Also the results of t-test were satisfied with conditions of p > 0.05. Therefore, these results were airy similar to the acceleration applied from function generator. As a result, the usefulness of the system was confirmed. n a further study, clinical experiment will be carried out with the authorization of IRB (institutional review board) so that appropriate frequency and strain would be investigated in clinical field.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.135-144
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• 2009

The purpose of this study is to develop a simple and rational crack evaluation system using Marshall tester. Fracture energy were used as a parameter to evaluate the crack resistance of asphalt mixtures. Marshall tester basically measures the vertical deformation obtained from the linear variable differential transformer(LVDT) attached on the specimen's exterior, which can cause a measurement error due to the local deformation near the loading head. Therefore, the validity of the measurement system of Marshall tester should be tested to use it in calculation of fracture energy. Two types of indirect tensile strength tests were performed using four types of asphalt mixtures at two temperature conditions. From the tests, it was shown that local deformation near the loading head had not occurred before a specimen was fractured, so that it did not cause the measurement error of fracture energy. And also from the statistic analysis, the coefficient of variation of vertical deformation measurements obtained on specimen's exterior is less than 15%. Thus, vertical deformation measurements obtained on the specimen's exterior can be used in crack evaluation system using Marshall tester.

• Journal of the Korean Geosynthetics Society
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• v.19 no.4
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• pp.75-84
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• 2020

This paper described the analysis result on heaving of soft ground with DCM column type, based on the results of laboratory model tests on the soft ground with DCM column. The heave characteristics of the soft ground were evaluated according to the application of DCM column in soft ground. The results showed that the heaving of soft ground without DCM column occurred rapidly when the lateral deformation of soft ground increased significantly under the 4th load step condition. In addition, the heaving of soft ground in final load step caused tensile failure of the ground surface. The maximum heaving of the soft ground with the DCM column occurred in the final load step, and the heaving quantity decreased in the order of pile, wall, and grid type. Especially, the soft ground with DCM of grid type effectively resisted ground heaving, even if it was extremely failure in the bottom ground of embankment. The results of the maximum heaving according to the measurement point showed that the heaving of the soft ground with DCM of grid type was 3.1% and 1.6% compared to that of the pile and wall type at the location of LVDT-1, and the heaving of the LVDT-2 position was 1.0% and 2.1%, respectively.