• Journal of the Korean Society of Radiology
• /
• v.6 no.5
• /
• pp.357-363
• /
• 2012

The purpose of this study on head computed tomography scan corporate reorganization adaptive iteration algorithm using the statistical noise, and quality assessment, reduction of dose was evaluated. Head CT examinations do not apply ASIR group [A group], ASIR 50 applies a group [B group] were divided into examinations. B group of each 46.9 %, 48.2 %, 43.2 %, and 47.9 % the measured in the phantom research result of measurement of CT noise average were reduced more than A group in the central part (A) and peripheral unit (B, C, D). CT number was measured with the quantitive analytical method in the display-image quality evaluation and about noise was analyze. There was A group and difference which the image noise notes statistically between B. And A group was high so that the image noise could note than B group (31.87 HUs, 31.78 HUs, 26.6 HUs, 30.42 HU P<0.05). The score of the observer 1 of A group evaluated 73.17 on 74.2 at the result 80 half tone dot of evaluating by the qualitative evaluation method of the image by the bean curd clinical image evaluation table. And the score of the observer 1 of B group evaluated 71.77 on 72.47. There was no difference (P>0.05) noted statistically. And the inappropriate image was shown to the diagnosis. As to the exposure dose, by examination by applying ASIR 50 % there was no decline in quality of the image, 47.6 % could reduce the radiation dose. In conclusion, if ASIR is applied to the clinical part, it is considered with the dose written much more that examination is possible. And when examination, it is considered that it becomes the positive factor when the examiner determines.

• Journal of Environmental Impact Assessment
• /
• v.4 no.3
• /
• pp.1-8
• /
• 1995

In generally speaking, the purpose of Environmental Impact Assessment(EIA) is to give the environment its due place in the decision-making process by clearly ealuating the environmental consequence of a proposed activity before action is taken. The introduction of conventional EIA is to be seen as an end product of a very long evolutionary process, starting with rudimentary but evolving pollution control measures for air, water, noise, land and chemicals, each governed by separate, and separately administered pieces of legislation. In EIA process, the measures of status, scoping, proposed mitigation and communication have not been very quantitative in their significancy. Of course, the determinations have uncertainity in the implications for significant impacts. To improve the determination of significant impacts, some more comprehensive methodologies of EIA has been proposed with the concepts of risk analysis in the proposed projects. The concepts of risk analysis has been introduced to the expression of human health impairment due to environmental pollutants since the early 1980's. The risk analysis being meant by the statistical significance of impact has a process quantitatively considering uncertainities and importances of ecological systems and human health as well. The process of risk analysis shows assessment, doseresponse in toxicity, exposure assessment and risk characterization. With the risk assessment, it could be suggested for the proper measurements against their anticipated risk in the EIA. This paper deals the priciples developing process and application of the risk-based analysis in EIA.

• Journal of Environmental Health Sciences
• /
• v.46 no.5
• /
• pp.539-547
• /
• 2020

Objectives: This study was performed to emphasize improvement of the perception of dental hygienists' environmental working conditions by analyzing various factors. Methods: Two hundred ninety-eight female dental hygienists working at 35 medical institutions in Daegu City and Gyeongsangbuk-do Province participated. A self-recording type survey was done in October 2016. Results: Factors influencing the perception of infection control was length of career. Dental hygienists with more experience have a higher level of perception. Factors influencing the perception of working posture was the number of patients per day and career level. Dental hygienists seeing 50 or fewer patients per day and senior staff showed higher levels of this perception. Factors influencing the perception of noise in the working area were length of career and lunchtime break. The perception level was high in the group with longer careers and dental hygienists who rest at lunch time. Factors influencing chemical exposure during work were the number of patients per day and the type of institute. Dental hygienists working in dental clinics or dealing with more patients had lower levels of perception. Conclusions: The sociodemographic and working characteristics of dental hygienists influence the perception of dental hygienists' environmental working conditions.

• Journal of KSNVE
• /
• v.10 no.2
• /
• pp.247-253
• /
• 2000

The evaluation of the ride quality had been performed by the subjective method before ISO2631(International Organization for Stadard 2631) and BS6841(British Standard 6841) was precented, but many research programs have been performed by the objective method after that. On this study, the ride quality was evaluated related with the objective method which considered the vibration which the human body feels on the driver's seat while driving on the road. In particular, we made the shock absorber nonlinear model and also selected the suitable shock absorber in the part of the vibration which the human body feels into the simulation. The shock absorber of suspension was dealt with 3 cases respectively with the front wheel and rear wheel. The vibration of the car driving on the road can be transferred to the wheel, the suspension, the vehicle body, the seat and the human body. The signal which was gained from the seat(hip) and the floor(foot) of the human body was changed to the vibration signal which the human body felt through using the frequency weighting function. And then the performance of the shock absorber was calculated through the statistic processing.

• Journal of Oriental Neuropsychiatry
• /
• v.12 no.2
• /
• pp.53-68
• /
• 2001

This study was performed to investigate the anti-depression effect of Guibiondamtang in rat model of depression. The rats in the experiment were stratified into 3 groups, ie, Guibiondamtang, saline, normal (non-stressed) groups. Chronic exposure to mild unpredictable stress such as white noise, flashing lights and restriction of food and water, causes the behavioral symptoms correspondent to depression. Consumption of 1% sucrose solution fell in rats exposed to CMS for 4 weeks. In the open field test , the exploratory activity ie. locomotion and centering decreased after CMS. We then evaluated the sucrose consumption and activity during 4 weeks of treatment with experimental drugs. The results were as follows: 1) There was no relation between sucrose intake and weight. 2) The Guibiondamtang(歸脾溫膽湯) group reinstated sucrose consumption within 5-6 weeks while having no influence on sucrose intake in normal group. 3) The Guibiondamtang(歸脾溫膽湯) group restored some exploratory activity in the open field test. 4) The Guibiondamtang-group had a-reduced potentiated startle response.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2013.06a
• /
• pp.274-277
• /
• 2013

CT(Computed Tomography)영상에서 선량과 화질은 중요한 요소이다. 선량은 환자에게 직접적으로 악영향을 끼치는 요소이며, 화질은 환자의 병변을 판단하는데 매우 중요하게 작용한다. 반복적 재구성 알고리즘을 이용하면 저선량 영상에서도 고화질의 영상을 얻을 수 있는지 FBP와 정량적, 정성적으로 비교하였다. 촬영 프로토콜은 관전압 80, 100, 120kVp에서 관전류를 동일하게 200mA로 촬영하여 획득하였으며, 정량적 평가를 위해 SD(Standard Deviation), SNR(Signal to Noise Ratio), MTF(Modulation Transfer Function)를 측정하여 분석하였다. 선량은 80kVp일 때 가장 낮았으며, 120kVp일 때 가장 높았다. 80kVp의 영상을 Toshiba 사(社)의 AIDR 3D(Adaptive Iterative Reduction integrated into $^{SURE}Exposure$)로 재구성하고, 120kVp의 영상에 FBP로 재구성한 다음 정량적 비교를 한 결과 AIDR 3D를 적용한 영상의 SD가 낮게 나왔으며, SNR이 높게 나타났고, MTF 곡선은 유사하게 나타났다. 그리고 FWHM(Full Width at Half Maximum) 값의 오차가 거의 없었다. 결론적으로 AIDR 3D는 저선량에서도 높은 화질을 나타냄을 확인하였다.

• Journal of the Ergonomics Society of Korea
• /
• v.15 no.2
• /
• pp.25-36
• /
• 1996

The purposes of the present study were: (1) to investigate aeromedical dissorders prevalent among ROK air force pilots and (2) to evaluate their detrimental effects on flight performance. The study examined the eight flight-induced disorders primarily responsible for permanent grounding and flying restrictions. According to the survey of 600 randomly selected pilots, 80.2% of the respondents have experienced low back pain, which was 20% higher than the lifetime prevalence in Swedish male workers. Bradyacusia ranked second (56.0%) resulting from continuous exposure to high aircraft noise. The cardiovascular disorders, the most common cause for permanent grounding of Canadian forces pilots, were found in 16.0% of the Korean pilots. Due to the high prevalence of the disorders, in 1993 the Korean pilots received medical treatments 10 times as many as factory workdes. Compared to the flight performance of Israeli and British pilots in wars, the flight performance of the Korean pilots was found to be inferior. Such poor performance can be attributable to the high incidence rates of disorders. Statistical analyses revealed that the aeromedical disorders were related to personal variables such as age, flight career- related factors, and fatigue. Cigarette smoking and drinking habit contributed to worsening back pain, barotitis media, and pulmonary disorders. More comprehensive research was recommended to identify health hazards, combined with intervention to minimize disorders that could lead to early termination of flight careers or excessive loss of flight time. This study further suggests that aeromedical institutions in Korean air force should be fostered more professionally and financially.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.9
• /
• pp.936-943
• /
• 2003

The miniaturized wireless endoscope consists of CMOS Image sensor, FPGA, LED, Battery, DC to DC Converter, Antenna and Transmitter. FSK transmitter is designed and fabricated with 10 mm(diameter)${\times}$23 mm(thickness) dimension considering the maximum permission exposure(MPE), system size, power consumption, linearity and modulation method. Experimental results is - 3.67 dBm output power level, 20 MHz frequency deviation, and - 99 dBc/Hz(@100 kHz offset) phase noise at 1.2 GHz. From the in-vivo experiment, the designed FSK transmitter has a acceptable capability for wireless endoscope.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.1
• /
• pp.92-92
• /
• 2010

A short-period comet, 17P/Holmes, is one of the most outstanding comets because of the outburs in 2007. It orbits the sun at the distance between 2.1AU and 5.2 AU with the orbital period of 6.9 year. On 2007 October 23, its brightness was suddenly increased by about a million times from 17 mag to 2.5 mag. We made observations of 17P/Holmes soon after the outburst on October 25, 27 and 28, using a 105cm telescope at the Ishigakijima Astronomical observatory, Japan. We took the images with V, R and I-band filters simultaneously. Total exposure times are 15 (October 25), 69 (October 27), and 37 (October 28) minute in each filter. The composite images provide good signal to noise ratio and help us to recognize faint structures embedded in the dust cloud. We examined a sequence of images using a digital filter that enhances the small-scale structures. As the result of the data analysis, we confirm (1) the radial expanded structure coming out from the nucleus of comet, and (2) dozens of blobs that moved radially away from the nucleus. In this presentation, we introduce the observations and the data reductions, and consider the origins of these fine structure.

• Journal of Broadcast Engineering
• /
• v.16 no.2
• /
• pp.247-257
• /
• 2011

In this paper, we propose a scene adaptive method to obtain two LDR images with proper shutter speeds which capture the irradiance of scene effectively. The proposed method adaptively selects two shutter speeds across the video frame even when the illumination varies continuously. For the performance evaluation, we compute the PNSR to the ground truth which is obtained by the state-of-the-art HDR imaging method. It shows that the proposed method is able to select approximately optimal shutter speeds while avoiding the exhaustive search of every possible pair of shutter speeds.