• Journal of radiological science and technology
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• v.42 no.1
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• pp.25-30
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• 2019

Whole Spine Scanography (WSS) using the Digital Radiography (DR) system is an examination that requires whole body X-ray exposure, which involves more exposure to radiation for patients than other general radiographies. This can affect the occurrence of breast cancer. This research measured radiation dose when breasts were shield and not shield using the Auto Exposure Control (AEC) mode. The radiation dose without a shield was 1.540 mGy, and that using a collimator was measured 0.506 mGy. Moreover, 0.733 mGy was measured when 1 shield (0.3 mm) was used, and $0.523{\mu}Gy$ when 5 of them (1.5 mm) were used. The results showed that the radiation dose with 5 shields and the radiation dose with a collimator were similar. Moreover, 0.233 mGy was measured when 8 shields (2.4 mm) were used. The standard deviation were 0.081 when using collimator and 0.014 when 5 shields were used. Also, when 8 shields were used, it was found to be 0.002. Most patients who go under a scoliosis test are children or young people who are highly sensitive to radiation. In the research results, the case where the organs sensitive to radiation, women's breasts, were shielded showed more distinct differences compared to without shields. It is considered that using shields can provide more constant shield than using a collimator and lower the risk of breast cancer caused by exposure to radiation.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.309-314
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• 2007

Originating from the Oort cloud, some comets disappear to impact against the Sun or to split up by strong gravitational force. Then they don't go back to the Oort cloud. They are called sungrazing comets. The comets are detected by sublimation of ices and ejection of gas and dust through solar heat close to the Sun. There exists the charge transfer from heavy ions in the solar wind to neutral atoms in the cometary atmosphere by interaction with the solar wind. Cometary atoms would be excited to high electronic levels and their do-excitation would result in X-ray emission, or it would be scattering of solar X-ray emission by very small cometary grains. We calculated the X-ray emission applying the model suggested by Mendis & Flammer (1984) and Cravens (1997). In our estimation, the sungrazing comet whose nucleus size is about 1 km in radius might be detectable within a distance of 3 solar radius from the sun on soft X-ray solar camera.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.44-50
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• 2009

High-pressured jetting is now widely used in the advanced cutting processes of polymers, metals, glass, ceramics and composite materials because of some advantages such as heatless and non-contacting cutting. Similarly to the focused laser beam machining, it is well known as a type of high-density energy processes. High-pressured jetting is going to be developed not only to minimize the cutting line width but also to achieve the short cutting time as soon as possible. However, the interaction behavior between a work piece and high-velocity abrasive particles during the high-pressured jet cutting makes the impact mechanism even more complicated. Conventional high-pressured jetting is still difficult to apply to precision cutting of micro-scaled thin work piece such as thin metal sheets, thin ceramic substrates, thin glass plates and TMM (Thin multi-layered materials). In this paper, we proposed the advanced high-pressured jetting technology by introducing a new abrasives supplying method and investigated the optimal process conditions of the cutting pressure, the cutting velocity and SOD (Standoff distance).

• Journal of the Korean Society of Safety
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• v.35 no.2
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• pp.84-93
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• 2020

In recent years, the scale of damage from disasters such as earthquakes and large-scale fires and floods that are occurring in Korea is increasing. Accordingly, interest in urban disaster prevention that combines living infrastructure such as roads and parks is boosting, and it is urgent to prepare measures to reduce the damage scale of local cities. The purpose of this study is to derive implications for disaster prevention measures in areas where disaster prevention safety of local cities is weak through examples of disaster prevention safety of local cities in case of disaster. To this end, this study analyzed the regional characteristics, current status, and disaster prevention problems of regional cities in Japan, and selected disaster-vulnerable areas, and considered the distance relationship between disaster prevention bases through road network analysis. In addition, road closure simulation using ArcGIS Network Analyst was conducted to analyze disaster prevention safety in the area. As a result, the situation of the village which has a high possibility of isolation by natural disasters was grasped in advance. Through this, the suburbs confirmed the necessity of supplementing the disaster prevention function through transportation maintenance such as forest roads, and it was found that the city needs to prepare a risk management system. Furthermore, this study suggests the need for research on areas with a high possibility of isolation, especially in areas where disaster prevention functions are weak in local cities in case of disaster, and shows countermeasures for disaster prevention measures and resident education.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.94-104
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• 2012

The purpose of this research is to quantify the compliance of on-road emission from a light duty diesel vehicle, based on a comparison to emission regulation standard. $NO_x$, CO and THC emissions were measured using a portable device on a selected real-world driving route with a length of approximately 22 km. On-road measurements were repeated by 10 times on a same route to reflect variability in traffic conditions. A test route was divided into 22 road links with length of 1 km to analyze emission results with higher spatial resolution. The average emissions of $NO_x$, CO and THC over total travel distance, which is approximately 220 km, were quantified to be in compliance with emission regulation standards. Under higher spatial resolution, $NO_x$ concentration exceeded a standard in 92 links out of 220 links. The extended time in stop period and the stop-and-go driving cycle were identified as two important reasons for increased $NO_x$ emissions in observed cases. Heavy traffics showed higher $NO_x$ emissions than free flow. These results indicate that the real-world vehicle emissions might exceed the compliance level associate with traffic conditions. Another interesting observation of this research is that the on-road emission characteristics can be independent to the average speed of road links with higher spatial resolution. Variability in on-road emission might not be fully described by solely relying on an average speed, because variability in traffic conditions and road conditions can influence on real-world vehicle emissions.

• The Journal of Korean Physical Therapy
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• v.21 no.4
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• pp.23-30
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• 2009

Purpose: This study investigated the efficacy of task-related circuit training aimed at improving balance in individuals discharged from rehabilitation facilities following a stroke. Methods: We recruited 12 stroke patients (34-66 years of age) to participate in a task-related circuit training program. Baseline assessment included a history of stroke and an assessment using the Mini-Mental State Examination Korea (MMSE-K). After a baseline assessment, follow-up assessments were administered pre- and post-training. These included Berg Balance Scale (BBS), Functional Reach Test (FRT), and the Time Up & Go Test (TUG). Physiotherapists trained study subjects under the one-to-one supervision of students from the department of physical therapy. Circuit class study participants attended 90-minute treatment sessions, one day a week for 12 weeks (from September to December 2008). The program consisted of a light warm-up period (10 min), physical exercises for improving balance (20 min), tasks focused on improving balance (50 min) and a cool-down period (10 min). Results: Scores for the BBS assessment increased significantly (from 43.2 to 49.7) after the training (p<0.05). Reach distance on the FRT increased substantially (from 27.7 cm to 47.0 cm), although the improvement was not significant (p>0.05). The average time on the TUG test decreased significantly (from 23.7 sec to 19.5 sec) after the training (p<0.05). Conclusion: The task-related circuit training program improved the balance and mobility of subjects, indicating that such a group program is useful for stroke patients who are discharged from the hospital. More such task-related programs set in a community environment should be developed.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.619-628
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• 2021

Background and objective: Native to the limestone zones of the Korean Peninsula, Zabelia tyaihyonii is a popular plant for landscaping. As it is now classified as a rare species, the conservation of its genetic resources is necessary. Methods: In this study, which aimed to understand the morphological variation of Z. tyaihyonii, 18 characteristics of Z. tyaihyonii from five habitats were examined. Results: Of these 18 characteristics, 16 characteristics showed significant differences among sites, and the coefficient of variation ranged from 5.4% (for corolla lobe number) to 31.3% (for flower number). Notable variations were observed in the size of flower and calyx lobe. When the corolla length and calyx lobe length were used as the classification key of Z. tyaihyonii, the sites were divided into those with small, intermediate, and large values. Hair was observed on the filament of all samples, a finding which conflicts with an earlier report. Rather than classifying Z. tyaihyonii into different species on the basis of corolla length (COL) and calyx lobe length (CALL) values, we recommend modifying the species description to incorporate the variation in these characteristics of interest. Principal component analysis results showed that the first main component was highly correlated with the traits related to the size of the calyx lobe (length: 0.819, width: 0.758), and the second main component was highly correlated with the traits related with the size of the inflorescence (length: 0.790, width: 0.626). Conclusion: Several notable variations were identified among the characteristics related to inflorescence and calyx lobe. There is little genetic exchange among groups, or each group is influenced by micro environmental factors, because sites that are located nearby. In addition, the difference between COL and CALL, which is used as the classification key for Z. tyaihyonii, was divided into small group, large group, and intermediate group, regardless of the sites' geographical distance.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.140-144
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• 2011

As a result of that the domestic railway technology has been progressed as times go by, the 1st and the 2nd steps for Gyeongbu HSR at the speed of more than 300km/h, were completed and Honam HSR - its operational speed is 350km/h - is under construction. Additionally, As a part of the expressization project for general lines, the Seoul-Chuncheon route at the speed of more than 180[km/h] is under construction and the Jeolla route is under design. At present, 11 countries (e.g. France, Germany, Belgium, Italy, the Netherlands, Spain, England, Japan, China and Taiwan) including Korea have high speed railways operated at the speed of more than 300[km/h]. As shown in the above, the domestic railway has high speed trains as good as those of countries outside Korea, but the schedule speed, which is calculated by dividing distance to destination by time, is lower than that of overseas trains. For overseas railway, the ratio of schedule speed to the highest speed is above 65%, while that of domestic railways is over 50%. It shows a significant difference between them. It is expected that the schedule speed improvement will increase the number of train operation and line capacities than now, so it shall achieve smooth transportation flow and improve the passengers' satisfaction. In this paper we describe the necessity for the improvement of schedule speed, by analyzing foreign cases related to the improvement of schedule speed in order to satisfy the increasing traffic demand.

• Journal of Cadastre & Land InformatiX
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• v.44 no.2
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• pp.103-112
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• 2014

The objective of this study is to suggest the possibility on land cover classification using hyperspectal imagery on area which includes lands and waters. After atmospheric correction as a preprocessing work was conducted on hyperspectral imagery acquired by airborne hyperspectral sensor CASI-1500, the effect of atmospheric correction to a few land cover class in before and after atmospheric correction was compared and analyzed. As the result of accuracy of land cover classification by highspectral imagery using reference data as airphoto and digital topographic map, maximum likelihood method represented overall accuracy as 67.0% and minimum distance method showed overall accuracy as 52.4%. Also product accuracy of land cover classification on road, dry field and green house, but that on river, forest, grassland showed low because the area of those was composed of complex object. Therefore, the study needs to select optimal band to classify specific object and to construct spectral library considering spectral characteristics of specific object.

• Journal of International Academy of Physical Therapy Research
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• v.5 no.1
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• pp.683-690
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• 2014

This study purposed to provide a scientific base for understanding the effect of therapeutic intervention using motivation on chronic stroke patients' balance and determining whether it is applicable as a new therapeutic intervention. For this study, we sampled 38 chronic stroke patients, and divided them randomly into a motivation training group(n=20) and a control group(n=18). To the control group was applied neurological physiotherapy 5 times a week, and 30 minutes each time, and to the motivation training group was applied neurological physiotherapy and then, additionally, a Nintendo Wii-Fit program 3 times a week, and 30 minutes each time. Before and after the experiment, the subjects' dynamic balance was measured with functional reach test(FRT), timed up & go test(TUG), and 10m gait test, and their static balance was measured with the Romberger Test. When dynamic balance ability was compared between before and after the experiment and between the motivation training group and the control group, significant difference was observed in the results of FRT, TUG, and 10m walking test between before and after the intervention(p<.05). As to static balance, in addition, body balance movement distance was not significantly different. Therapeutic intervention using dynamic motivation was found to be more effective than the control group in improving dynamic balance.