• Journal of radiological science and technology
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• v.36 no.1
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• pp.11-17
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• 2013

Currently, there are many studies being conducted around the world to reduce exposure dose to radiation for patients to receive medical treatments in a safe environment. We developed and fabricated of this shield that the patients are protected from the radiation and are need of safety control during breast imaging. In this study, for breast imaging, GE Senography 2000D were used and set at SID 65cm, 28kVp, and 63mAs. The measuring instrument was Fluke's Victoreen 6000-529. And we performed Face Block on with 30 patients. The chamber on the actual thyroid glands to take CC and MLO and measure the dosage before and after wearing the Face Block. For the results, after wearing the Face Block, exposure was decreased by 53.8%-100% and 65.8% in average in CC View and by 50%-100% and 60.7% in average in MLO View. The development of the Face Block that practically decreased the exposure dose of thyroid glands, crystalline eyes during breast imaging and reduced the patients' anxiety during breast imaging. The Face Block is expected to improve patients' satisfaction and contribute to reducing patients' exposure dose, but more efforts should be made to reduce exposure dose to medical radiation.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.67-77
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• 2003

The purpose of this study is to provide the criteria for implementing unprotected left turn at intersections with variation of traffic volume on a cross road approach. Using Transyt-7F model, the delays calculated from permissive and protected left turn signal system were compared by gradually increasing the left turn volume for a certain opposing through volume up to the volume limits to which permissive left turn is more effective, Average stopped delay of the intersection was used as the measure of effectiveness in this study. The major conclusions are (1) the lighter the traffic gets in a cross road, the more the allowable left turn volume increases. The allowable left turn volume when the ratio of cross traffic to the concerned approach traffic is 0.6 appears about 50% more than the volume when the ratio is 1.0. (2) Comparing to the criteria of the manual of traffic safety facility, the results when the traffic ratio is 0.6 seem to be most similar the criteria of manual and the results when the traffic ratio are 0.8 and 1.0 appears to be lower than the criteria of manual. (3) The possible amount of making a left turn that is inversely proportional to the opposing through traffic, decreases as the number of opposing through lanes increases. The products of volume need to be used as the criteria of permissive left turn with considerable cautions because of its low consistency.

• Fire Science and Engineering
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• v.25 no.2
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• pp.101-106
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• 2011

In case of an emergency such as a fire on a building and there is a need to evacuate the occupant in that building, it is important to have the guidance information effectively delivered to the evacuating occupants to guide them toward a safe direction using audio sensual media. And, it is also very important to prevent the evacuating occupants getting lost or falling astray, away from the direction toward safety. The purpose of this study, in this respect, is to examine the possible application of the precedent sound effect, with which the evacuating occupants may get a sense of the direction where the announcement comes from. With such an effect, an experiment was conducted to measure the extent to which people can hear the preceding and the following sound in terms of the acoustic pressure level changes and delay time changes, with a view to make the optimal evacuation-guidance announcement or sound. The optimal evacuation guidance sound (announcement) per each of the experimental indoors environments were as follows; 1) Regarding the optimal condition for the evacuation guidance announcement sound in the space of a lecture room, the direction of the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~50 ms in comparison with the advanced sound or when there is no difference between the acoustic pressures of the advanced and follow-up sounds or the acoustic pressure of the advanced sound is higher than that of the follow-up sound. 2) Regarding the optimal evacuation guidance announcement sound in the space of a hall, the advanced sound is positively recognized when the follow-up sound has the delaying time of 20 ms~60 ms in comparison with the advanced sound. 3) Regarding the optimal evacuation guidance announcement sound in the space of a gymnasium, the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~40 ms in comparison with the advanced sound or when the sound pressure of the advanced sound has a higher level than or the same level as that of the follow-up sound.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.403-411
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• 2016

Recently, the number of occurrences of inundation and the severity of flood damage has increased rapidly as the frequency of localized heavy rainfall and the ratio of impervious area increased in urban areas. Most local governments focus on employing structural measures (e.g., the construction of detention reservoirs/pump stations, rehabilitation of drainage and sewer pipes) to prevent urban inundation. On the other hand, the effectiveness of implementing such structural measures is being dimished because there are already many inundation prevention facilities. The limitation of structural measures can be overcoming by employing non-structure measures, such as flood alerts and the operation of drainage facilities. This study suggests the pump operation rule (i.e., suggesting pump stop level) for a new detention reservoir operating method, which triggers the operation of a pump based on the water level at the monitoring node in urban drainage system. In the new reservoir operation, a total of 48 rainfall events are generated by the Huff distribution for determining the proper pump stop level. First, the generated rainfall events are distributed as frequencies, quartiles, and durations. The averaged system resilience value was determined to range from 1.2 m to 1.5 m is based on the rainfall-runoff simulation with rainfall generated by the Huff distribution. In this range, 1.2 m was identified considering the safety factor of 1.25 by the Standard on sewer facilities in 2011.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.500-508
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• 2014

For this research, synthesis acrylic resin by ethyl acrylate monomer(EAM) and prepared samples which set by difference amount of monoammonium phosphate solution in waterborne acrylic resin. Use these resins, analyzed mechanical properties and thermal stability by films and leather surface coated. The test of DSC experiment sample WAC-APS3 was $410^{\circ}C$ Tm values which means the highest content of monoammonium phosphate had highest thermal stability in acrylic resin. According to measure data for solvent resistance, all samples showed good property. As known in the results, increase of ammonium phosphate constant did not influence to big change of resin properties. In abrasion test WAC-APS3 was good abrasion properties(68.729 mg.loss). Test of tensile strength, as increase as monoammonium phosphate resin analyzed low properties $1.505kgf/mm^2$ to $1.275kgf/mm^2$. In elongation case, same as strength test result 425 % to 384 % by increase to monoammonium phosphate amount in acrylic resin.

• Journal of the Korean Geotechnical Society
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• v.33 no.9
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• pp.5-22
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• 2017

The procedure that combines the result of infiltration analysis into stability analysis based on the limit equilibrium method is widely used to evaluate the impact of rainfall infiltration on slope stability. Accurate prediction of rainfall infiltration is essential to the prediction of landslides caused by rainfall, requires to obtain accurate unsaturated hydraulic properties of the soil. Among the unsaturated hydraulic characteristics of the soil, the importance of the soil-water characteristic curve describing the retained water characteristics of the soil is relatively well known and the measurement by test method to obtain the SWCC is gradually increasing. However, it takes a lot of time and expenses to experimentally measure the unsaturated conductivity characteristics of the soil. Therefore, it is common practice to estimate the hydraulic conductivity function from the SWCC. Although it is widely known that the SWCC has a great influence on rainfall infiltration, studies on the effect of the hydraulic conductivity function estimated from the SWCC on rainfall infiltration are very limited. In this study, we explained how the estimation model of the hydraulic conductivity function affects rainfall infiltration and slope stability analysis. To this end, one-dimensional infiltration analysis and slope stability analysis were conducted by using the data on the SWCC of weathered granite soil widely distributed in Korea. The applicability of each estimation model is discussed through review of the analysis results.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.2
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• pp.129-140
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• 2018

A residual stress generated in the steel structure is broadly categorized into initial residual stress during manufacturing steel material, welding residual stress caused by welding, and heat treatment residual stress by heat treatment. Initial residual stresses induced during the manufacturing process is combined with welding residual stress or heat treatment residual stress, and remained as a final residual stress. Because such final residual stress affects the safety and strength of the structure, it is of utmost importance to measure or predict the magnitude of residual stress, and to apply this point on the design of the structure. In this study, the initial residual stress of steel structures having thicknesses of 25 mm and 70 mm during manufacturing was measured in order to investigate initial residual stress (hereinafter, referred to as initial stress). In addition, thermal elastic plastic FEM analysis was performed with this initial condition, and the effect of initial stress on the welding residual stress was investigated. Further, the reliability of the FE analysis result, considering the initial stress and welding residual stress for the steel structures having two thicknesses, was validated by comparing it with the measured results. In the vicinity of the weld joint, the initial stress is released and finally controlled by the weld residual stress. On the other hand, the farther away from the weld joint, the greater the influence of the initial stress. The range in which the initial stress affects the weld residual stress was not changed by the initial stress. However, in the region where the initial stress occurs in the compressive stress, the magnitude of the weld residual compressive stress varies with the compression or tension of the initial stress. The effect of initial stress on the maximum compression residual stress was far larger when initial stress was considered in case of a thickness of 25 mm with a value of 180 MPa, while in case of thickness at 70 mm, it was 200 MPa. The increase in compressive residual stress is almost the same as the initial stress. However, if initial stress was tensile, there was no significant change in the maximum compression residual stress.

• Korean Journal of Optics and Photonics
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• v.31 no.1
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• pp.13-19
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• 2020

To measure underwater acoustics using a fiber-optic Sagnac interferometric sensor, the sensitivities of ring-type probes are investigated by theoretical and experimental studies. A ring-type probe was fabricated by packaging a single-mode fiber wound around an acrylate cylinder of diameter 5 cm with epoxy bond. The probes were prepared as A-type, which was packaged with 46.84 m of sensing optical fiber, and B-type, which was packaged with 112.22 m of sensing fiber. The underwater acoustic test was performed at frequencies of 50, 70, and 90 kHz, and over a range of acoustic pressure of 20-100 Pa, to study the sensitivity. A commercial acoustic generator was located 1 m from the acoustic sensor, such as the ring-type probe or a commercial acoustic sensor. From the experimental test, the acoustic sensitivity of the ring-type probe had different values due to acoustic frequencies, unlike the theoretical prediction. Therefore, the experimental sensitivities were averaged for comparison to the theoretical values. These averaged sensitivities are 25.48 × 10^-5 rad/Pa for the A-type probe and 60.79 × 10^-5 rad/Pa for the B-type probe. The correction coefficient of Young's modulus c was determined to be 0.35.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1278-1295
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• 2014

The Sixteenth Meeting of the Conferences of Parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which was held in March 2013 in Bangkok, Thailand, listed five shark species and one genus, and uplisted one sawfish species. All new species listings will be come into force of the eighteen months delay, on the fourteenth of September, 2014. The purpose of the delay is to support the preparation of the domestic measures on shark trade by the parties, as there has been no previous experience in trading the commercially exploited aquatic species in the CITES. The CITES Secretary-General has visited several potential shark trade countries to encourage and facilitate the implementation of the new CITES listings. The newly listed sharks have been caught as a target or non-target species by Korean distant water fisheries and introduced into Korea. So the establishment or change of the domestic laws, regulations, and measures for the implementation of the new CITES species must be prepared before the effective entry date. This paper is prepared to assess the effects of the trade of the CITES listed shark species, and to suggest effective government service measures for the management of Korean distant water fisheries. The Ministry of Environment (MOE) is the general Management Authority of the CITES, and the Ministry of Food and Drug Safety (MFDS) is in charge of the medical trade of CITES listed species in Korea. By law, all imported medicines and medical materials must be inspected by the MFDS during the customs examination; this kind of authority sharing is reasonable and effective way of providing government service. Similarly, the designation of new CITES Management Authority for the trade of commercially exploited aquatic CITES species is critical and the Ministry of Oceans and Fisheries (MOF), which is now in charge of the trade of fisheries products, is the most appropriate governing body for this purpose in Korea. The revision of the National Plan of Action for Conservation and Management of Sharks, initially submitted to the Food and Agriculture Organization (FAO) of the United Nations in 2011 as a practical guideline for shark conservation in all Korean fisheries, could be a effective measure to achieve unification of conservation of endangered species and sustainable use of fisheries stocks. The proper CITES measures for the trade of listed species, such as the establishment of the documenting system for Non-detriment Findings, domestic measures suitable for the "Introduction from the Sea" clause, species specific Harmonized System Codes for the customs service, and an effective shark catch data reporting system should be in place prior to the fourteenth of September 2014.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.443-449
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• 2021

In this study, the purpose is to present the foot inclination angle for realizing an image similar to that of the existing examination method and to present the clinical usefulness of the new examination method through comparison between the existing examination method and the newly designed standing foot oblique projection. A foot phantom was used, and the magnification of the image according to the angle was quantitatively evaluated by attaching a nut to the position of the cuboid of the phantom. The internal oblique image acquired using a 30° wedge was set as the standard image. And that image was compared with the images acquired by changing the angle of the foot from 20° to 65° at intervals of 5°. Image evaluation was performed by 3 radiological technologists, and qualitative evaluation using a Likert 5-point scale for evaluation items of true oblique view and quantitative evaluation of the value obtained by measuring the diameter of a nut in each image were performed as image evaluation. For data analysis, reliability analysis between the measure and comparative analysis of the average value for each angle were performed. The qualitative evaluation score for each image was 4.5 to 5 points for most questions in the case of the standard image. And 4 points or less for most questions in the images with a foot angle of 45° or less, and an evaluation score close to the standard image was obtained in the image of 50° or more. And in the quantitative evaluation, the diameter of the nut was measured to be 9.28~9.56 mm. The qualitative evaluation showed a reliability of 0.95~1.0 and the quantitative evaluation was 0.62. As a result of comparing and analyzing the average of the quantitative and qualitative average values for each angle image, the group with the average value most similar to the standard image was images obtained at 55° and 60°, and in the post-analysis, the images of both groups were the same group as the standard image(p<0.01). As a result of this study, it was found that the angle of inclination of the foot for realizing the image most similar to the existing image in the standing foot oblique projection is 55°~60°. In addition, if this test method is applied to the clinic, it is believed that it will help prevent safety accidents such as falls during the test and improve test efficiency by minimizing the movement of patients for the test.