• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.525-531
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• 2021

The importance and utilization of underground spatial is increasing due to urban concentration. And so underground spatial information is being built. Because underground spatial information is an important NSDI (National Spatial Data Infrastructure), the accuracy and performance of underground spatial exploration devices used for construction are managed separately. In accordance with the laws and regulations related to spatial information, the government is conducting performance tests for underground facilities surveying equipment. The current performance test site mainly targets metal pipelines, and there is no absolute position surveying inspection system. In this study, test bed model for performance inspection of underground space exploration equipment was presented. The test bed presented in this study can be used as a test site to supplement the limitations of the existing domestic test bed and to verify the performance of the latest equipment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.21-28
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• 2022

The TMD has a simple structure than other vibration control devices and shows excellent control performance for the simple harmonic vibration generated in the structure. However, the vibration control range is narrower than other control devices, making it vulnerable to vibration cycles caused by unexpected external loads. The ETMD developed in this study consisted of Mass with electromagnets. Therefore when supplying a current, the magnetic field is formed to increase the friction force with the friction plate, thereby instantaneously controlling the behavior of the Mass. The experiment was conducted to compare the control performance of the control device by installing the ETMD developed for control performance evaluation in the center of the model simple beam bridge to forced excitation at 3.02 Hz where the maximum bending displacement occurs. As a result of the experiment, ETMD exhibited excellent control performance with a maximum bending displacement attenuation rate of 57.51%.

• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.33-37
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• 2004

As the high speed and high integration of semiconductor devices and the generation of heat increases resulted in the effective heat dissipation influences on the performance and lifetime of semiconductor devices. The heat resistance or heat spread function of EMC(epoxy molding compound) which protects these devices became one of very important factors in the evaluation of semiconductor chips. Recently, silica, alumina, AlN(aluminum nitride) powders are widely used as the fillers of EMC. The filler loading in encapsulants was high up to about 80 vol%. A high loading of filler was improved low water absorption, low stress, high strength, better flowability and high thermal conductivity. In this study, the thermal properties were investigated through thermal, mechanical and microstructure. Thermophysical properties were investigated by laser flash and differential scanning calorimeter(DSC). For detailed inspection of materials, the samples were examined by SEM.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.5
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• pp.411-429
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• 2022

Instrumentations are essential in NATM tunnels, however measuring instruments are installed and applied without performance verification procedures due to insufficient research on methods, procedures, regulations, etc. to verify the reliability of the measuring instruments. In this study, domestic and foreign regulations relating to the verification and calibration of instruments were investigated and necessities for accreditation standards were proposed. In order to identify the causes of the defects, an external inspection was performed on rock bolt stressmeter and rod extensometer, which are measuring instruments with relatively complex structures. For verifying the performance of these instruments, verification devices were developed that can load step-by-step and the causes of defects were identified in measuring instruments of nine domestic manufacturers. Through the performance test, a number of measuring instruments were found to be defective. It was important to test the performance of the instruments in the state of a finished product and accordingly performance inspection methods and procedures were proposed. The results of this study are expected to help preparing related regulations for verifying instrument performance and selecting instruments in the field.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.107-115
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• 2014

In this study, we examined the seismic isolation effects due to the difference between the center of mass of the building and the center of stiffness of isolation layer. Because the base isolation technique is a technique that is highly dependent on the performance of seismic isolation devices installed on the seismic isolation layer, we have to examine the horizontal stiffness of seismic isolation devices after making them. If difference between the design stiffness and the actual stiffness of the seismic isolation device occurred, a big problem may be generated in the upper members on the seismic isolation layer. The analytical results show that the more eccentricity increases, the more maximum response acceleration, story shear and the member forces of the upper part of the structure increases, and the damage is expected to be in excess. Therefore, it is recommended that if possible, isolation devices have to be designed to coincide the center of mass of the building with the center of stiffness of isolation layer. If not after making isolation devices, they need to be relocated to prevent the eccentricity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.8
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• pp.1106-1112
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• 2018

In this paper, measurement techniques are presented to test the performance of insulation without interruption if it is difficult to measure insulation resistance. Especially, non-contact voltage phase detection techniques have been developed that can be applied in environments where it is difficult to find voltage measurement locations such as component receptors. The performance verification of the non-interrupting insulation resistance measuring devices has been tested against existing products using standard calibration equipment and test jigs. The validation confirmed performance within 2 % for direct contact type and within 10 % for non-contact type. In addition, the procedure to make continuous insulation test using the equipment was proposed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.118.3-118
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• 2001

CLED (Contact Light Emitting Device) has three layers consisting of a transparent electrode, a light emitting layer and a substrate. When the substrate of the CLED comes in contact with a fingerprint under AC input voltage, it makes an electric field between the fingerprint and the device. Due to the electric field, the light is emitted along the ridgeline of the fingerprint. The intensity along the ridge on the surface of the CLED increase in proportion to the electric field. To achieve uniform performance of fingerprint verification devices, inspection system of CLED for quality control were required. In this research, we proposed the factors for quality controls such as dimensions of the CLED, uniformity ...

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.887-893
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• 2018

The purpose of this study is to compare the performance of X-ray generators installed in hospitals and universities and apply the quality control items of diagnostic X-ray generators to recognize the importance of periodic performance management. First, the reproducibility and linearity test results showed that the PAE of the reproducibility evaluation was high for the GX-650 devices that met the acceptance criteria in all the experimental conditions and lacked the periodic quality control. In the linearity evaluation, when the tube voltage was set to 100 kVp, It was measured to deviate from the error. In addition, it was found that the PAE in the low-accuracy evaluation results relative to an X-ray tube voltage and tube current of the device low occurrence frequency. The HVL experiment was included in all of the devices at the HVL by tube voltage. Therefore, it is necessary to recognize the importance of quality control of all devices rather than hospital and laboratory, and to manage the device performance by actively managing the device, and to establish a short - term quality control system like special medical devices.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.21-30
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• 2018

Building structures of apartment in korea conventionally adopt shear walls using coupling beams as seismic force-resisting systems. Energy dissipating devices employed the building structures are used instead of the coupling beams in order to increase the seismic performances by providing additional damping and stiffness. This study aims to introduce energy dissipating devices which are preferred in structural system and aims to investigate structural behaviors of shear wall structures employing such devices instead of coupling beams. In order for achieve research objectives, Finite Element Analysis and Nonlinear analysis was carry out. Finite Element Analysis results was correspond with experimental results and this is indicated that the device can provide sufficient additional damping and stiffness into shear wall structures. Throughout nonlinear static analyses, examples structures with the devices can enhance seismic performance of building structures due to their sufficient energy dissipating capacities. Especially, strength and ductility capacities were significantly improved when it is compared with the performance of building structures without the devices. Throughout nonlinear dynamic analyses, it was observed that structural damages can be mitigated due to reduced seismic demands for seismic force-resisting systems. It is especially noted due to the fact that story drifts, accelerations, shear demands are reduced by 15~18%, 20~28% and 15~20%, respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.13-20
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• 2013

In order to reduce seismic responses of a structure, additional dampers and vibration control devices are generally considered. Usually, control performance of additional devices are investigated for optimal design without variation of characteristics of a structure. In this study, multi-objective integrated optimization of structure-smart control device is conducted and possibility of reduction of structural resources of a building structure with smart top-story isolation system has been investigated. To this end, 20-story example building structure was selected and an MR damper and low damping elastomeric bearings were used to compose a smart base isolation system. Artificial earthquakes generated based on design spectrum of low-to-moderate seismicity regions are used for structural analyses. Based on numerical simulation results, it has been shown that a smart top-story isolation system can effectively reduce both structural responses and isolation story drifts of the building structure in low-to-moderate seismicity regions. The integrated optimal design method proposed in this study can provide various optimal designs that presents good control performance by appropriately reducing the amount of structural material and damping device.