• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.4
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• pp.171-180
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• 2000

This study aims to present a more reasonable control value than the exiting one by comparing and analyzing control values and field instrumentation values of the whole excavation depth of the four case sites using geometric averaging as a statistical method. The range of the study is confined to three things: (1) the axial force of the braced excavation walls among a variety of items prescribed in the control values by stress deformation of walls and adjacent structures; (2) by approximation of the allowable and design value; (3) and by safety factor. As a res it is desirable to revise "(Long term allowable stress + Short term allowable stress)/2 ~ Short term allowable stress," presented in the present control values by stress deformation of walls and adjacent structures, to "(Long term allowable stress + Short term allowable stress)/5 ~ (Short term allowable stress)/3." The result also shows that since there is a difference of about 3.5%, it is not necessary to revise 70, 90, and 100 percent of LEVEL I, II, and III, prescribed in the control values by the allowable and design value approximation. In addition, modifying the control value by the safety factor, now 1.07, is unnecessary, although it varies little difference from the present value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5269-5279
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• 2014

The cause of defects in the PCB SMT assembly is mostly solder paste deposits. Conventional inspection methods for solder paste deposits suffer from slow speed, low reliability and high cost. Therefore, this paper proposes a method for calculating the height and region of solder paste on PCB using the 3D profiles without measuring the 2D image. The solder paste region is detected by the phase difference in the measurement points and the average phase on the whole surface of PCB. The high reliable height of the solder paste region is computed by the average of the measurement points' phase with repeatability and reliability. The experimental results revealed improvements of 17% in inspection time and 29% repeatability in the height calculation of the solder paste region, resulting in a high speed and less expensive system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.583-589
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• 2020

Recently, the utility of UAS (Unmanned Aerial System) for a smart farm using various sensors and ICT (Information & Communications Technology) is expected. In particular, it has proven its effectiveness as an outdoor crop monitoring method through various indices and is being studied in various fields. This study analyzes damage to crops caused by natural disasters and measures the damage area of rice plants. To this end, data is acquired using BG-NIR (Blue Green_Near Infrared Red) and RGB sensors, and image analysis and NDWI (Normalized Difference Water Index) index performed to review crop damage caused by in the rainy season. Also, point cloud data based on image analysis is generated, and damage is measured by comparing data before and after the typhoon through an inspection map. As a result of the study, the growth and rainy season damage of rice was examined through NDWI index analysis, and the damage area caused by typhoon was measured by analysis of the inspection map.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.423-428
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• 2023

In the missile actuator system, the time and position of the wings of the drive device are very important factors in the initial maneuver of the missile, and therefore, the missile actuator device must be inspected while ensuring the accuracy and real-time of motion collection data of the actuator. In this study, the difference between the design and implementation method for checking the existing actuator device and the design implementation method of the actuator device through the DAQ(Data Acquisition) device is compared, and the difference in data collection amount and real-time data collection performance is compared and tested, and the data shown through actual tests are compared. is converted into a graph, the actuator waveform is compared and analyzed, and based on the analyzed data, DAQ device inspection configuration that guarantees real-time response speed and stability during inspection of existing actuators and DAQ devices is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.140-146
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• 2008

The damage evaluation method for framed structures using continuous wavelet transform (CWT) is proposed. CWT is applied to the response acceleration of a structure subjected to earthquake load to decompose the response acceleration corresponding to each scale, then the normalized energy value for each scale is calculated. The difference between the normalized energy curvature (NEC) in each node before and after damage indicates a damaged element, which makes it possible to assess the soundness of structural elements. As damage becomes more severe the difference in normalized energy curvature becomes larger. The NEC calculated from the signal corresponding to high scale in CWT analysis is found to be a good index that shows the location and severity of damage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.30-38
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• 2023

As the number of old buildings subject to safety inspection increases, the burden on designated institutions and management entities that are responsible for safety management is increasing. Accordingly, when selecting buildings subject to safety inspection, appropriate safety inspection standards and appropriate technology are essential. The current safety inspection standards for old buildings give low scores when it is difficult to confirm damage such as cracks in structural members due to finishing materials. This causes the evaluation results to be underestimated regardless of the actual safety status of the structure, resulting in an increase in the number of aging buildings subject to safety inspection. Accordingly, this study proposed a thermal imaging technique, a non-destructive and non-contact inspection, to detect cracks inside finishing materials. A concrete specimen was produced to observe cracks inside the finishing material using a thermal imaging camera, and thermal image data was measured by exciting a heat source on the concrete surface and cracked area. As a result of the measurement, it was confirmed that it was possible to observe cracks inside the finishing material with a width of 0.3mm, 0.5mm, and 0.7mm, but it was difficult to determine the cracks due to uneven temperature distribution due to surface peeling and peeling of the wallpaper. Accordingly, as a result of performing data analysis by deriving the amplitude and phase difference of the thermal image data, clear crack measurement was possible for 0.5mm and 0.7mm cracks. Based on this study, we hope to increase the efficiency of field application and analysis through the development of technology using big data-based deep learning in the diagnosis of internal crack damage in finishing materials.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.20-21
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• 2017

There have been reports in the media about some refineries that omit the refining process and deliver raw material for reasons of cost reduction, shortening of production time, etc. Also, in most RMC factories acceptance inspection is not conducted on account of issues with the proficiency of the equipment and cost issues; instead only scores are relied upon. Therefore this study sought to analyze the relation between the value of the density of FA actually delivered to RMC companies, attained with the Hydrometer method, and its fineness, to see whether the quality of FA can be evaluated statistically. Results led to the conclusion that there is a problem in terms of credibility in the fineness of FA shown on the test report. Upon analyzing the difference between the fineness of FA as measured using Blaine's air permeability method and its density of the Hydrometer method, the correlation was found to be satisfactory; therefore the possibility of a FA fineness quality evaluation could be proved as well.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.74-81
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• 2019

Cars are inspected in the transport sector for their ability to achieve the greenhouse gas reduction targets. A vehicle (automobile) inspection broadly consists of regular and total checks, and both the safety level and the amount of exhaust gas are checked simultaneously during a vehicle inspection. This study deals with the efficiency of a soot probe to measure soot emissions from diesel vehicles. When the vehicle exhaust gas measurement is performed, there may be a difference between the exhaust gas temperature and the soot suction amount because of the different shape and angle of the exhaust port for each vehicle type. This may result in some incidents where the correct inspection nonconforming vehicle is not selected. Therefore, in this study, the shape of the probe was improved to increase the soot measurement efficiency under the condition of the exhaust pipe angle change.

• Journal of the Korean Society of Radiology
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• v.4 no.3
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• pp.5-11
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• 2010

In this paper, we are suggested development of dual-mode detector for dual-energy digital radiography. Design of dual-energy radiography module for commercial BIS (Baggage Inspection System) is used in the spectrum of the X-ray generator and detector for dual-mode features and radiological characteristics were analyzed. BIS suggestl on the image detector module being used to target X-ray tube to simulate X-ray spectrum and simulated spectrum to offer through the new radiographic characteristics of the detector modules were investigated. Using X-ray experiments with an increase in the thickness of the copper filter low energy detector (LED) and high-energy detector (HED) as the difference between the output signal increases. HED, especially in the size of the output signal decreases with increasing thickness of the copper filter was found.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.63-64
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• 2014

NIR(New Inspection Regime, hereinafter NIR) relating to the PSC(Port State Contorl, hereinafter PSC) has implemented in Asia-Pacific region under Tokyo-MOU from last January 2014. The most noticable difference between NIR and existing TF(Target Factor, hereinafter TF) is to evaluate company performance and to conduct PSC with flexible inspection interval on the basis of Ship Risk Profile; High Risk Ship, Standard Risk Ship and Low Risk Ship.