• The Journal of Korean Society for Radiation Therapy
• /
• v.14 no.1
• /
• pp.175-186
• /
• 2002

The purpose of this study is directly measure and evaluate about absorbed dose change according to nominal energy and electron cone or medical accelerator on isodose curve, percentage depth dose, contaminated X-ray, inhomogeneous tissue, oblique surface and irradiation on intracavitary that electron beam with high energy distributed in tissue, and it settled standard data of hish energy electron beam treatment, and offer to exactly data for new dote distribution modeling study based on experimental resuls and theory. Electron beam with hish energy of $6{\sim}20$ MeV is used that generated from medical linear accelerator (Clinac 2100C/D, Varian) for the experiment, andwater phantom and Farmer chamber md Markus chamber und for absorbe d dose measurement of electron beam, and standard absorbed dose is calculated by standard measurements of International Atomic Energy Agency(IAEA) TRS 277. Dose analyzer (700i dose distribution analyzer, Wellhofer), film (X-OmatV, Kodak), external cone, intracavitary cone, cork, animal compact bone and air were used for don distribution measurement. As the results of absorbed dose ratio increased while irradiation field was increased, it appeared maximum at some irradiation field size and decreased though irradiation field size was more increased, and it decreased greatly while energy of electron beam was increased, and scattered dose on wall of electron cone was the cause. In percentage depth dose curve of electron beam, Effective depth dose(R80) for nominal energy of 6, 9, 12, 16 and 20 MeV are 1.85, 2.93, 4.07, 5.37 and 6.53 cm respectively, which seems to be one third of electron beam energy (MeV). Contaminated X-ray was generated from interaction between electron beam with high energy and material, and it was about $0.3{\sim}2.3\%$ of maximum dose and increased with increasing energy. Change of depth dose ratio of electron beam was compared with theory by Monte Carlo simulation, and calculation and measured value by Pencil beam model reciprocally, and percentage depth dose and measured value by Pencil beam were agreed almost, however, there were a little lack on build up area and error increased in pendulum and multi treatment since there was no contaminated X-ray part. Percentage depth dose calculated by Monte Carlo simulation appeared to be less from all part except maximum dose area from the curve. The change of percentage depth dose by inhomogeneous tissue, maximum range after penetration the 1 cm bone was moved 1 cm toward to surface then polystyrene phantom. In case of 1 cm and 2 cm cork, it was moved 0.5 cm and 1 cm toward to depth, respectively. In case of air, practical range was extended toward depth without energy loss. Irradiation on intracavitary is using straight and beveled type cones of 2.5, 3.0, 3.5 $cm{\phi}$, and maximum and effective $80\%$ dose depth increases while electron beam energy and size of electron cone increase. In case of contaminated X-ray, as the energy increase, straight type cones were more highly appeared then beveled type. The output factor of intracavitary small field electron cone was $15{\sim}86\%$ of standard external electron cone($15{\times}15cm^2$) and straight type was slightly higher then beveled type.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.1
• /
• pp.54-59
• /
• 2000

This paper presents a control system that uses a fuzzy algorithm in controlling the depth of a model midwater trawl net, and experimental results carried out in the circulating water channel by using a model trawl winch system.The fuzzy controller calculates the length of the warp to be changed, based on the depth error between the desired depth and actual depth of the model trawl net and the ratio of change in the depth error. The error and the error change are calculated every sampling time. Then the control input, i.e. desirable length of the warp, is determined by inference from the linguistic control rules which an experienced captain or navigator uses in controlling the depth of the trawl winch controller and the length of the warp is changed. Two kinds of fuzzy control rules were tested, one was obtained from the actual operations used by a skilled skipper or navigator, and the other was a modified from the former by considering the hydrodynamic characteristics of the model trawl system.Two kinds of fuzzy control were tested, one was obtained fro the actual operations used by a skilled skipper or navigator, and the other was a modified from the former by considering the hydrodynamic characteristics of the model trawl system.The results of these model experiments indicate that the proposed fuzzy controllers rapidly follow the desired depth without steady-state error although the desired depth was given in one step, and show robustness properties against changes in the parameters such as the change of the towing sped. Especially, a modified rule shows smaller depth fluctuations and faster setting times than those obtained by a field oriented rule.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.232-235
• /
• 2003

In general, the parameters of climate change include aerosol chemical compounds, aerosol optical depth, greenhouse gases(carbon dioxide, CFCs, methane, nitrous oxide, tropospheric ozone), ozone distribution, precipitation acidity and chemical compounds, persistent organic pollutants and heavy metals, radioactivity, solar radiation including ultra-violet and standard meteorological parameters. Over the last ten years, the monitoring activities of Korea regarding to the climate change have been progressed within the WMO GAW and ACE-Asia IOP programs centered at the observation sites of Anmyeon and Jeju Gosan islands respectively. The Greenhouse gases were pointed out that standard air quality monitoring techniques are required to enhance data comparability and that data presentation formats need to be harmonized and easily understood. Especially, the impact of atmospheric aerosols on climate depends on their optical properties, which, in turn, are a function of aerosol size distribution and the spectral reflective indices. Aerosol optical depth and single scattering albedo in the visible are used as the two basic parameters in the atmospheric temperature variation studies. The former parameter is an indicator of the attenuation power of aerosols, while the latter represents the relative strength of scattering and absorption by aerosols. For aerosols with weak absorption, surface temperature decreases as the optical depth increases because of the domination of backscattering. For aerosols with strong absorption, however, warming could occur as the optical depth increases. The objective of the study is to characterize the means, variability, and trends of Greenhouse gases and aerosol properties on a regional basis using data from its baseline observatories in Korea peninsula. A further goal is to understand the factors that control radiative forcing of the greenhouse and aerosol.

• Journal of Periodontal and Implant Science
• /
• v.32 no.3
• /
• pp.631-642
• /
• 2002

The present study evaluated of regeneration effect of platelet rich plasma on the treatment of classII furcation involvement, with allograft in humans. The control was treated without bioabsorbable membrane, and the test was treated with bioabsorbable membrane. Pocket depth, clinical attachment level, and gingival recession were measured at baseline, postoperative 3, 6months. Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth and clinical attachment level in both groups was decreased significantly at 3, 6months.(p<0.05) 2. The change of gingival recession in both groups was increased significantly at 3, 6months than at baseline.(p (0.05) 3. The change of pocket depth and clinical attachment level in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 4. The change of gingival recession in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 5. The significant reduction of the pocket depth and clinical attachment level exhibited marked changes at 3 months in both groups. In conclusion, the results of this study suggest that there are no statistically or clinically significant differences between with and without bioabsorbable membrane on treatment of classII furcations using allograft and PRP

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.3
• /
• pp.583-597
• /
• 1998

The purpose of this study was to evaluate temperature change occurred in enamel, dentin and pulp due to the heat from cavity prepration with laser. We made three models had different cavity depth: cavity depth of model A was 3.52mm, model B was 2.32mm, model C was 1.16mm. We irradiated cavity base with thermal capacity of $30J,100J,300J/cm^2s$ during few seconds and studied the change of temperature in tooth during 10 seconds, and estimated change of thermal capacity by different irradiated site and exposure time. At $300J/cm^2$ irradiation for 2 seconds, the temperature of irradiated surface was elevated fast according to irradiated thermal energy during 1 second. In proportion to continuous exposure time, temperature elevated slowly. The surface temperature was $1370^{\circ}C$. After discontinue of thermal irradiation, the heat of irradiated surface was diffused in dentin and pulp and the greatest temperature was made. The greatest temperature was disappeared within 10 seconds The greatest temperature of the inner part of model brought about very severe change by different depth. Temperature in pulp was raised by the greater irradiated energy density and exposure time.

• Science of Emotion and Sensibility
• /
• v.16 no.1
• /
• pp.29-42
• /
• 2013

In this paper, we analyze the effect of the depth perception, volume perception and visual discomfort according to the change of the quality of the depth image and the depth of the major object. For the analysis, a 2D image was converted to eighteen 3D images using depth images generated based on the different depth position of a major object and background, which were represented in three detail levels. The subjective test was carried out using eighteen 3D images so that the degrees of the depth perception, volume perception and visual discomfort recognized by the subjects were investigated according to the change in the depth position of the major object and the quality of depth map. The absolute depth position of a major object and the relative depth difference between background and the major object were adjusted in three levels, respectively. The details of the depth map was also represented in three levels. Experimental results showed that the quality of the depth image differently affected the depth perception, volume perception and visual discomfort according to the absolute and relative depth position of the major object. In the case of the cardboard depth image, it severely damaged the volume perception regardless of the depth position of the major object. Especially, the depth perception was also more severely deteriorated by the cardboard depth image as the major object was located inside the screen than outside the screen. Furthermore, the subjects did not felt the difference of the depth perception, volume perception and visual comport from the 3D images generated by the detail depth map and by the rough depth map. As a result, it was analyzed that the excessively detail depth map was not necessary for enhancement of the stereoscopic perception in the 2D-to-3D conversion.

• Journal of the Korean Geographical Society
• /
• v.42 no.1 s.118
• /
• pp.121-132
• /
• 2007

This paper examines the spatial and temporal variability in the water depth caused by artificial structures in Geum Estuary of South Korea. Water depth data set extracted from marine maps of 1979, 1990, 1996 and 2004 were used in a GIS to derive volumetric estimates of gains and losses of sedimentary material. Artificial structures caused above 2m in water depth to be shallow between 1979 and 2002 in the estuary system, particularly through disturbance of a natural transport in suspended sediment concentrations. The mutt significant change in suspended sediment transport were observed in area affected by embankment for fresh water, inducing the water depth shallower than before in almost 80% of the area. This was probably because of an continuous abundant mud supply from coastal river oven after blocking the fresh water. The spatial analysis made it possible to identify area wide patterns of water depth change subject to many different type of artificial structures, which tanner be acquired by traditional field sampling. It is anticipated thai this research could be used as a valuable reference to confirm the outputs from past field researches for sedimental process in more visual and quantitative manner.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2004.11a
• /
• pp.39-42
• /
• 2004

The Central Electrode Correction Factor that corrects the effect due to the electrode being made of non-air material is base on the data from the depth of 5cm in water. But TG-51 protocol proposes the reference depth of 10cm in water. The purpose of this research is to check the alteration of Central Electrode Correction Factor due to the change of reference depth from 5cm to 10cm in water using Monte Carlo Computing Methods. The results showed that the change of Central Electrode Correction Factor is ignorable in the statistical errors of 2% for two different depth, 5cm and 10cm.

• Journal of Periodontal and Implant Science
• /
• v.31 no.2
• /
• pp.477-488
• /
• 2001

The present study evaluated of regeneration effect of platelet rich plasma on the treatment of grade II furcation involvement, with coralline calcium phosphate bone in humans. 30 teeth with grade II furcation defect were selected and 15 teeth(control) were treated with coralline calcium phosphate bone, the others(test) were treated with coralline calcium phosphate bone and platelet rich plasma. Pocket depth, clinical attachment level, width of keratinized gingiva width were measured at baseline, postoperative 3, 6months. from cementoenamel junction to alveolar crest and fundus were measured at baseline, 6months(re-entry). Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program(5% significance level). The results were as follows: 1. Pocket depth, clinical attachment level, keratinized gingva width, cementoenamel junction - alveolar crest, cementoenamel junction - fundus were not differ significantly in both groups at baseline 2. The change of pocket depth, clinical attachment level, keratinized gingva width, cementoenamel junction - alveolar crest, cementoenamel junction - fundus in both groups were decreased significantly at 3, 6months(p<0.05). 3. The change of pocket depth, clinical attachment level in test group decreased significantly than control at 3, 6months(p<0.05). 4. The change of keratinized gingiva width, cementoenamel junctional - alveolar crest, cementoenamel junction - fundus were not differ significantly in both groups at 3, 6months. 5. The pocket depth, clinical attachment level, keratinized gingiva width exhibited marked changes at 3 months in both groups. In conclusion, the results of this study suggest that platelet rich plasma have adjunctive clinical treatment effect to periodontal regeneration in grade II furcation defects.

• Journal of Korea Water Resources Association
• /
• v.39 no.2 s.163
• /
• pp.179-186
• /
• 2006

We analyzed the harmonic and non-harmonic constant of Geum River estuary to know tidal change of the before and after construction at Geum River estuary dike. As a result of analysis, the harmonic and non-harmonic constant after estuary dike building increased. Also, depth change analyzed at each section by using each year chart data. As a result, scour was occurred in the channel between south and north side guide bank. And accretion was occurred at channel from Kunsan outer port to estuary dike. Tidal change was judged as the effect of construction and dredge, watergate closing at Geum River estuary dike. And water depth change is a cause by effection of Geum River estuary dike construction and, south-north side guide bank, Kunjang country industrial complex furtherance business, seamangeum 4th sea bankment construction.