• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.183-194
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• 2004

It's essential process to study non-linear material function related to characteristics of compressibility and permeability when we predict the consolidation behavior of soft clay ground. In this study, laboratory tests were conducted to find out the material function using marine clay. Standard oedometer test and Rowe cell test were performed with conditions, which were classified into vertical drainage only, radial drainage only and vertical-radial drainage case. Modified oedometer test equipment was developed to find out the material function and special extrusion device was originated to minimize the sample disturbance effect. Reliability of the results in modified oedometer test could be confirmed by comparing with the Rowe cell's one. Effective stress - void ratio - permeability relations were analyzed using all testing results. As a result, void ratio with effective stress level could be expressed by the power function and permeability with void ratio could be expressed by exponential function. In soft clay with high initial water content and low shear strength, non-linear characteristics related to compressibility and permeability varied with wide range by the effective stress levels. It's important to note that non-linearity of the material function should be considered at prediction of the consolidation behavior.

• Journal of the Korean Society of Radiology
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• v.18 no.2
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• pp.171-177
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• 2024

In this study, two general X-ray device, CT, and MRI inspection devices were selected from general hospitals in the Daejeon area and an experiment was conducted to predict the level of infection by measuring the surface contamination of the inspection devices at different times and to use it as basic data for infection prevention. As a result, the surface contamination level by time zone for general X-ray devices and MRI examination devices was in the order of 13H > 8H > 16H, and for CT examination devices, it was 13H > 16H > 8H, which appeared to be influenced by the number of tests. In addition, the surface contamination results for each part of the test device showed that the highest ATP contamination value was found on the stand bucky handle for the general X-ray device, the headrest for the CT examination device, and the operation switch for the MRI examination device, which was closely related to the number of contacts. As a result of comparing before and after disinfection, all devices showed a significant decrease after disinfection. Based on the results of the experiment, it is believed that it can be used as basic data to identify the level of contamination in radiology laboratories and prevent infectious diseases.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.82-89
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• 2024

Black ice is very difficult to recognize and reduces the friction of the road surface, causing automobile accidents. Since black ice is difficult to detect, there is a need for a system that identifies black ice in real time and warns the driver. Various studies have been conducted to prevent black ice on road surfaces, but there is a lack of research on systems that identify black ice in real time and warn drivers. In this paper, an real-time image-based analysis system was developed to identify the condition of asphalt road surface, which is widely used in Korea. For this purpose, a dataset was built for each asphalt road surface image, and then the road surface condition was identified as dry, wet, black ice, and snow using deep learning. In addition, temperature and humidity data measured on the actual road surface were used to finalize the road surface condition. When the road surface was determined to be black ice, the salt spray equipment installed on the road was automatically activated. The surface condition recognition system for the asphalt concrete pavement and black ice automatic prevention system developed in this study are expected to ensure safe driving and reduce the incidence of traffic accidents.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.133-144
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• 2006

In order to catch out such Bond Strength, the preceding researchers had ever examined the Bond Strength of FRP Plate through their experimentations by setting up of various fluent. However, since the experiment for research on such Bond Strength takes much of expenditure for equipment structure and time-consuming, also difficult to carry out, it is conducting limitedly. This Study purposes to develop the most suitable Artificial Neural Network Model by application of various Neural Network Model and Algorithm to the adhering experiment data of the preceding researchers. Output Layer of Artificial Neural Network Model, and Input Layer of Bond Strength were performed the learning by selection as the variable of the thickness, width, adhered length, the modulus of elasticity, tensile strength, and the compressive strength of concrete, tensile strength, width, respectively. The developed Artificial Neural Network Model has applied Back-Propagation, and its error was learnt to be converged within the range of 0.001. Besides, the process for generalization has dissolved the problem of Over-Fitting in the way of more generalized method by introduction of Bayesian Technique. The verification on the developed Model was executed by comparison with the resulted value of Bond Strength made by the other preceding researchers which was never been utilized to the learning as yet.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.315-322
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• 2014

This study demonstrates holding condition of CT by medical institution classification and by season, and examination fee in Korea currently to quantitatively understand frequency of examination region by change of CT equipment, domestic growing trend and change of distribution and using rate. Recent 10 years of CT holding condition by medical institution classification (Tertiary hospital, General hospital, Hospital, Clinic, Dental hospital, Dental clinic, Hospitalized health center) and by year (2003-2012), and CT examination fee of distribution of medical institution by year is surveyed. The holding ratio of Tertiary hospital level and General hospital level is 32.7% in 2003 and 33.0% in 2012. Whereas, Hospital and Clinic level is 74.2% in 2003 and 66.8% in 2012, which takes approximately 70%. Based on data in 2012, it is 82.2% of total examination fee in Tertiary hospital and General hospital, while 17.5% in hospital and clinic. CT holding rate of Hospital level is increasing, while Clinic level is decreasing. Approximately 80% of CT examination fee is claimed by Tertiary hospital and General hospital. Therefore, there is a significant correlation between CT holding condition of medical institution classification and examination fee. Particularly, correlation between CT holding number of Tertiary hospital and examination fee is significant (p<.001). The more CT holding number, the higher the amount claimed examination fee.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.213-220
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• 2015

This research was study the accuracy of three-dimensional stereotactic breast biopsy, using a core Needle Biopsy and to assess the accuracy of Stereotactic biopsy and Sono guided biopsy. Using Stereotactic QC phantom to measure the accuracy of the 3D sterotactic machine. CT Scan and equipment obtained in the measured X, Y, Z and compares the accuracy of the length. Using Agar power phantom compare the accuracy of the 3D sterotactic machine and 2D ultrasound machine. Z axis measured by the equipment to compare the accuracy and reliability. Check the accuracy by using visual inspection and Specimen Medical application phantom. The accuracy of the 3D sterotactic machine measured by Stereotactic QC phantom was 100%. Accuracy as compared to CT, all of X, Y, Z axis is p > 0.05. The accuracy of the two devices was 100% as measured by Agar powder phantom. There was no difference between t he t wo d evices as C T and p > 0.05. 3D sterotactic machine of the ICC was 0.954, 2D ultrasound machine was 0.785. 2D ultrasound machine was different according to the inspector. Medical application phantom experiments in 3D sterotactic machine could not find the Sliced boneless ham. 2D ultrasound machine has not been able to find a small chalk powder group. The reproducibility of the three-dimensional stereotactic breast biopsy was better than effect of Sono guided biopsy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.37-43
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• 2018

A developer solves problems with isolating failures if faults are detected when inspecting missiles using the missile assembly test set (MATS) and then resumes the testing. In order to identify faults, it is necessary to analyze the data coming from the equipment, but the information received may not be sufficient, depending on the inspection environment. In this case, the developer repeats the test until the problem is reproduced or checks the performance of each piece of equipment that is related to the fault. When this task is added, schedule management becomes problematic, and development costs rise. To solve this problem, we need to design a MATS in a systematic way to increase fault coverage while satisfying the required reliability. By designing the necessary processes for each procedure, it is possible to reduce the fault identification time when a fault is detected during operations. But it is not possible to guarantee 100% fault coverage, so we provide another method by comparing costs and effects. This paper describes a development method to enhance the reliability of the missile assembly test set; it describes the expected effects when it is adapted, and describes the limitations of this method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.443-450
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• 2020

This paper reports a design improvement study to solve the stoppage phenomenon caused by the launch-support device applied to K105A1. The K105A1 is a weapon system equipped with an old 105 mm towed howitzer in a wheeled vehicle, which provides superior maneuverability compared to track equipment. The launch support device serves to withstand fire impact and load. In this way, this device is fixed firmly to the ground in preparation for the shooting mission and is responsible for the critical performance, such as fixing the position of the vehicle. On the other hand, during the field test, a temporary stoppage of the launch support occurred, which caused a problem of not being fixed to the ground. To solve this problem, the cause of failure was analyzed by a replay test and parts inspection. In addition, the operating concept, method, and design were analyzed to derive the cause and solve the problem by changing the parts design. Finally, the performance and firing missions were performed normally by applying the changed design to K105A1. The performance stability and reliability of the launch support device were confirmed, which are expected to be of great assistance in the development of military equipment in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.46-56
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• 2013

This research prepared safety standard for out-door fitness and this research's purpose is to evaluate and investigate safety condition for out-door fitness which was distributed in domestic residence by applying TUV standard which evaluate product's safety inspection. We choose twelve companies which have many sales' amount and investigated for ten out-door fitness which have high consumer preferences. As a result of that, the ratio of successful applicants for safety evaluation was 55.1%. The terms desired was evaluated highly in safety for out-door fitness's fixing condition. However, the terms desired was evaluated lowly in safety for movable condition. Fitness equipment which has high consumer preferences was compared lowly than other equipment in safety part. It was analyzed that there was no difference in safety evaluation according to manufacturing company. So, it is necessary to prepare safety standard by establishing law in order to prevent accident while they are using because we cannot think that fitness equipments which was distributed in domestic area have high safety. We think that preparing safety standard can influence on preventing accident and reinforcing out-door fitness manufacturing companies' competitive.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.183-188
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• 2017

In recent years, the automatic remote control controller of the gamma ray irradiator malfunctions, and radiation workers are continuously exposed to radiation exposure accidents. In the non-destructive testing field, much time and resources are invested in establishing a radioactive source monitoring system in order to prevent potential incidents of radiation. In this study, the gamma-ray response properties of the lead monoxide-based radiation detector were estimated through monte carlo simulation as a previous study for the development of a radioactive source location monitoring system that can be applied universally to various non-destructive testing equipment. As a result of the study, the optimized thickness of the radiation detector varies according to the gamma-ray energy emitted from the radioactive source, and the optimized thickness gradually increases with increasing energy. In conclusion, the optimized thickness of the lead monoxide-based radiation detector was $200{\mu}m$ for the Ir-192, $150{\mu}m$ for the Se-75 and $300{\mu}m$ for the Co-60. Based on these results, the appropriate thickness of lead monoxide-based radiation detector considering secondary-electron equilibrium was evaluated to be $300{\mu}m$ for general application. These results can be used as a basic data for determining the appropriate thickness required in the radiation detector when developing a radiation source location monitoring system for universal application to various non-destructive testing equipment in the future.