• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.6
• /
• pp.401-408
• /
• 2019

The objective of this study is to develop a new type of buried sensor module that can directly assess pre-stressed concrete by measuring strain using a hetero-core optical fiber sensor. In this regard, experiments were conducted to evaluate the performance of the sensor using an exposure sensor module. Based on the experimental results, when the values of the displacement control velocity were 0.12 mm/min and 1.80 mm/min, the corresponding delays in the measurement were 52.1 s and 2.6 s respectively, which indicated that the maximum delay between the two measurements was a factor of 19. Due to the measurement delay phenomena, the sensor module used in the experiments cannot be employed to check the real-time state of the structure. Thus, additional experiments were needed to develop a new sensor module that can measure the real-time state of the structure. To investigate the cause of the measurement delay phenomena, three experiments were conducted. It was confirmed that measurement delay is mainly attributed to frictional resistance. The measurement delay phenomena were not observed in the experiments using the friction-removed device.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.3
• /
• pp.276-283
• /
• 2012

In this study, it was studies the utilization of LIT(lock-in infrared thermography) which can detect defects in welded parts of ship and offshore structures. Quantitative analysis was used through methods of filtering and texture measurement of image processing techniques to find the optimized experimental condition. We verified reliability in our methods by applying image processing techniques in order to normalize evaluations of comparative images that show phase difference. In addition, low to mid exposure showed good results whereas high exposure did not provide significant results in regards to intensity of light exposure on surface. Lock-in frequency was satisfactory around 0.1 Hz regardless of intensity of light source we had. In addition, having the integration time of thermography camera inversely proportional to intensity of exposed light source during the experiment allowed good outcome of results.

• The Journal of the Korea Contents Association
• /
• v.11 no.12
• /
• pp.357-363
• /
• 2011

The aim of this study is to compare radiation dose in diagnostic X-ray radiography and calculated by different mathematical equation. The result of ESDs direct measurement and that calculated by Mori NDD-M shows the biggest difference. On the other hand, equation by Edmonds shows the lowest difference of ESDs. Also, Rectification due to the difference between direct dose measurement and calculation method commutated three-phase, single phase and inverter type, show less difference in the drive way. In conclusion, this study can be helpful for expecting radiation dose-exposure and control exposure parameters for the diagnostic x-ray radiography.

• Journal of the Korean Society of Radiology
• /
• v.9 no.6
• /
• pp.421-424
• /
• 2015

In this study, To subject the constructed at N-kindergarten in G-city, the position is closed window and opened window was measured using a measuring instrument for radon. The measured results indicate that the measurement was carried out in concentrations of radon gas measured at N-kindergarten is low than United States in the radon concentration in air public 4pCi called radon gas baseline maximum allowable concentrations. As a result, radon exposure is not a problem, but when the accumulation radon gas in the lungs, get damaged same lung cancer. Be defensive of kindergarten windows open for ventilation and dust removal be possible to reduce the exposure.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.601-602
• /
• 2012

• Environmental Analysis Health and Toxicology
• /
• v.17 no.2
• /
• pp.147-160
• /
• 2002

Volatile organic compounds (VOCs) are an important public health issue in Korea and many important questions remain to be addressed with respect to assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in their analytic determination Valid Personal exposure assessment methods are needed to evaluate exposure frequency, duration and intensity, as well as their relationship to personal exposure characteristics. Biological monitoring is also important since it may contribute significantly in risk assessment by allowing the estimation of effective absorbed doses. This study was on ducted to establish the environmental measurement, personal dosimetry and biological monitoring methods for VOCs. These methods are needed to compare blood, urinary and exhalation breath VOC levels and to provide tools for risk assessment of VOC exposure. Passive monitors (badge type) and a active samplers (trap) for the VOCs collection were used for air sampling. Methods development included determining the minimum detectable amounts of VOCs in each media, as well as evaluating collection methods and developing analytical procedures. Method reliability was assessed by determining breakthrough volumes and comparing results between laboratories and with other methods. A total capacity of trap used in this study was 60ι. Although variable by compound, the average breakthrough was 20％. Also, there was no loss of compounds in trap even if keep for 45 day in -7$0^{\circ}C$. The recovery of active and passive methods was 69％ ~ 126％ and method detection limit was 0.24 $\mu\textrm{g}$/trap and 0.07 $\mu\textrm{g}$/badge. There was no statistical difference (P > 0.05) between active and passive methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.5 s.108
• /
• pp.451-460
• /
• 2006

We have designed local exposure systems for long-time mice experiments in PCS and cellular frequency band(PCS: 1,762.5 MHz, cellular: 848.5 MHz). The fabricated systems are local exposure systems of carousel type, and 40 mice can be exposed at a time. In order not to give extra stress to the mice ender experiment, the systems were fabricated to meet the environmental conditions such as illumination, ventilation, noise etc. SAR measurement was performed using a temperature probe. Measurements at 3 points in the head of mouse cadaver and solid phantom were made, and it has been confirmed that the measurement results are in good agreement with the simulation results in the real exposure environment. The exposure systems are currently used for long-term mice experiments.

• Journal of radiological science and technology
• /
• v.46 no.2
• /
• pp.99-106
• /
• 2023

The height of the table should be considered important during computed tomography (CT) examination, but according to previous studies, not all radiology technologists set the table at the patient's center at the examination, which affects the exposure dose and image quality received by the patient. Therefore, this study intends to study the image quality exposure dose according to the height of the table to realize the optimal image quality and dose during the brain CT scan. The head phantom images were acquired using Philips Brilliance iCT 256. When the image was acquired, the table height was adjusted to 815, 865, 915, 965, 1015, and 1030 mm, respectively, and each scan was performed 3 times for each height. For the exposure dose measurement, optically stimulated luminescence dosimeter (OSLD) was attached to the front, side, eye, and thyroid gland of the head phantom. In the signal to noise ratio (SNR) measurement result, The SNR values for each table height were all lower than 915 mm. As a result of exposure dose, the exposure dose on each area increased as the table height decreased. The height of the table has a close relationship with the patient's radiation exposure dose in the CT scan.

• Journal of the Korean Society of Tobacco Science
• /
• v.19 no.2
• /
• pp.162-169
• /
• 1997

An important and somewhat under-emphasized issue in assessing the risk potentially associated with exposure to ETS is the reliability and objectivity of the methods used to measure the actual level of exposure. Objectivity of the science is crucial in this context since this topic tends to elicit strong social, emotional and political responses among the general public and the scientific community alike. This mini-review compares the strengths and limitations of various methods used in determining ETS exposure in scientific investigations. Methods reviewed include: questionnaire, area monitoring, bio-monitoring, and personal monitoring. In particular, results of several recent studies (conducted in the United States, Europe, and the Far East) using personal monitors in combination with questionnaire and bio-monitoring, which contribute to a more reliable, objective and realistic estimates of a person's actual exposure to 575, are discussed.

• Journal of Radiation Protection and Research
• /
• v.19 no.1
• /
• pp.37-50
• /
• 1994

The experimental evaluation of exposure conversion formula using the relationship between optical photo-density, exposure dose and the quality of radiation characteristics of radiation energy to X-ray and ${\gamma}-rays$. The film badge dosimeter is analysed by exposure conversion formula which evaluate image fading characteristics for development time and directional characteristics for incident beam angle. In conclusion, exposure conversion formula evaluated of this study is satisfied with quality decision criterion of the film badge dosimeter.