• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.15-29
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• 2004

The purpose of this study was to understand the relationship among knowledge, attitude, and behavior of dental personnel about the defense against dental radiation according to general features, and help them recognize the importance of defense against dental radiation. A questionnaire survey of 187 dental personnel who were working in 121 medical institutions such as university hospitals, general hospitals, hospitals, clinics, and public health centers in Seoul area was conducted from December 2002 to January 2003. Study findings are as follows: 1. The average knowledge score for the defense of radiation was 9.51(full score=14): By the demographic features, the know level for the defense of radiation was appeared to be different with the occupational category, age, academic background, workplace, year of working, and whether having the education of radiation or not. By questionnaire items, the knowledge for the defense of radiation was high in general, but for the item. 'the average amount of being bombed with radiation according occupations cannot be over 20mSv in a year for prescribed 5 years'. it was 18.7%: and for the item. 'the longer the length between focus and film. the less the amount of skin exposure', it was 40.6%. showing less knowledge for these two items. 2. The average attitude score for the defense of radiation was 64.24 (full score=75): By the demographic features, the attitude score was higher with respondents who were 31-35 years old. 11-15 years of working. and having radiation education. The attitude score by questionnaire items was generally high for all the items. 3. The average behavior score for the defense of radiation was 45.43: (a) By the demographic features, the behavior score for the defense of radiation was appeared to be higher with respondents who were dentists for occupational category, the aged for age, holding higher diploma for academic background, working in the university hospitals for workplace, and having longer occupational career for the year of working. (b) The behavior score for the defense of radiation by questionnaire items was lower than that of the attitude score for all the items. For the item, 'the amount of X-ray radiation is adjusted according to such conditions as patients' age, radiating areas, and kind of films', the score was 4.03; and for the item, 'Must receive the education of safety management of radiation periodically', the score was 1.73 and it was the lowest one. 4. As for the correlation among the knowledge, attitude, and behavior for the defense of radiation, the higher the level of knowledge and attitude, the higher the level of behavior.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.93-101
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• 2014

Underwater radiated noise is the key in acoustic stealth performance of modern naval ships. The underwater radiated noise predicted by the hull vibration with radiation efficiency cannot always give the information of radiation pattern which is essential to analyze of detection probability by enemy and to improve the operational performance of the naval ship. The radiation pattern of underwater radiated noise is able to be obtained with radiation efficiency and radiation directional coefficient. In this paper, a new method to extract the radiation efficiency and radiation directional coefficient is suggested and proved with the simulation and experiment by using cylindrical shell of 70 cm diameter in air.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.738-743
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• 2013

Underwater radiated noise is the key in acoustic stealth performance of modern naval ships. The underwater radiated noise predicted by the hull vibration with radiation efficiency cannot give the information of radiation pattern which is essential to the analysis of detection possibility by enemy and to improve the operational performance of the naval ship. The radiation pattern of underwater radiated noise is able to be obtained with radiation efficiency and radiation direction coefficient. In this paper, a new method to extraction the radiation efficiency and radiation direction coefficient is suggested and proved with the simulation and experiment by using cylindrical shell of 70cm diameter in air.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.12
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• pp.992-998
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• 2014

Acoustic radiation efficiency is one of the important factors in the prediction of underwater radiated noise of ships. A ship has much equipment to operate successful mission in a ship. Most of equipment is running simultaneously as multi-excitation and becomes the source of underwater radiated noise. In many cases of multi-excitation, phase difference between multi-excitation is not considered. Because vibration response under multi-excitation is the vector sum of each single excitation, acoustic radiation efficiency based on surface velocity field can be affected by phase of excitation. In this study, acoustic radiation efficiency of a plate on air and a stiffened cylindrical model in water under multi-excitation with phase difference is investigated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.11
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• pp.747-752
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• 2015

Underwater radiated noise is an important characteristic in the naval weapon systems. It is difficult to measure the radiation efficiency of underwater vehicle, such as UUV(unmanned underwater vehicle) and underwater weapons in real operation environment. In this study, acoustic radiation efficiency of a circular cylindrical structure is measured in the laboratory-water tank. The radiation efficiency is compared with the numerical results and it is found that they are in a good agreement. Therefore, the measurement method can be applied effectively for predicting the underwater radiation noise and effectiveness of radiation reduction means.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.191-195
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• 2012

Among the atmospheric effect of laser propagation, the variations of the radiation transmittance by water aerosol evaporation have quantitatively been investigated. When the aerosol was exposed by a 1.07 ${\mu}m$ cw fiber laser, the increased amount of the transmittance variation was a maximum of 19.1% and the volume concentration variation of aerosol was observed as an increasing of laser intensity. Also, significant irregularity of refractive index was not found in the heated area during the continuous laser heating.

• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.528-531
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• 2013

We report a case of infantile fibrosarcoma in an 8-month-old boy manifested as a right-sided lower leg mass. Repeated local recurrence and distant metastasis were noted during the following three-year period. Whole body fluoro-deoxyglucose positron emission tomography scan revealed an asymptomatic metastasis involving the fourth lumbar vertebrae. The patient received chemotherapy (VAC regimen) with Cyberknife$^{(R)}$ stereotactic hypofractionated radiotherapy (26 Gy; 4 fractions). This treatment reduced tumor size by 23% without acute radiation toxicity even after 33 months. This case suggests that combining chemotherapy and this form of radiotherapy may be safe and effective against childhood spinal metastasis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.876-882
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• 2014

This study investigates an efficient method to estimate the total acoustic radiation power of submerged circular cylindrical structures. Since the acoustic radiation power of submerged vehicles can be changed during the operation, the estimation for its monitoring onboard is required to accomplish the missions. The total acoustic radiation power is estimated using the measured velocity and the calculated radiation efficiency of the surface which consists of submerged rectangular plate elements. Experiments are carried out to validate the estimation approach. Comparisons of the estimation results with the measurements show that they are in a good agreement for the mid-high frequency range and match well for the cases of different excitation locations which correspond to the different operation modes of underwater vehicles as well. Therefore, this estimation method can be applied effectively to the development of the radiated noise monitoring-system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.763-769
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• 2014

This study is on the experiment and prediction of the pipe noise due to the internal fluid. The vibration of pipe external surface and noise in air were measured according to the internal fluid velocity and pipe type. In the experiment, the vibration and noise level of the straight pipe and rounded pipes show that the vibration and noise level are almost same. The 900 mitred pipe shows the high vibration and noise level. In the prediction of noise due to the internal flow, the method using the pipe surface vibration and radiation efficiency shows good agreement with experimental result.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.770-779
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• 2014

In this study, a numerical estimation method for 3D underwater radiated noise pattern using hull vibration and total acoustic power of the vibrating structure in the far-field is proposed. The underwater radiated noise pattern is known to be predicted using the vibration signals and radiation efficiency of each surface patch. But it is very difficult to know radiation efficiency of each surface patch which is one of important factors to calculate the 3D underwater radiated noise pattern. Instead of using radiation efficiency of each patch, the underwater radiated noise level is modified with the total acoustic power of the vibrating structure. The suggested estimation method for underwater radiated noise pattern is discussed with numerical model.