• Radiation Oncology Journal
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• v.23 no.4
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• pp.236-242
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• 2005

Purpose: To evaluate the role of surgical clips and scars in determining electron boost field for early stage breast cancer undergoing conserving surgery and postoperative radiotherapy and to provide an optimal method in drawing the boost field. Materials and Methods: Twenty patients who had $4{\sim}7$ surgical clips in the excision cavity were selected for this study. The depth informations were obtained to determine electron energy by measuring the distance from the skin to chest wall (SCD) and to the clip implanted in the most posterior area of tumor bed. Three different electron fields were outlined on a simulation film. The radiological tumor bed was determined by connecting all the clips implanted during surgery Clinical field (CF) was drawn by adding 3 cm margin around surgical scar. Surgical field (SF) was drawn by adding 2 cm margin around surgical clips and an Ideal field (IF) was outlined by adding 2 cm margin around both scar and clips. These fields were digitized into our planning system to measure the area of each separate field. The areas of the three different electron boost fields were compared. Finally, surgical clips were contoured on axial CT images and dose volume histogram was plotted to investigate 3-dimensional coverage of the clips. Results : The average depth difference between SCD and the maximal clip location was $0.7{\pm}0.55cm$. Greater difference of 5 mm or more was seen in 12 patients. The average shift between the borders of scar and clips were 1.7 1.2, 1.2, and 0.9 cm in superior, inferior, medial, and lateral directions, respectively. The area of the CF was larger than SF and IF in 6y20 patients. In 15/20 patients, the area difference between SF and if was less than 5%. One to three clips were seen outside the CF in 15/20 patients. In addition, dosimetrically inadequate coverage of clips (less than 80% of prescribed dose) were observed in 17/20 patients when CF was used as the boost field. Conclusion: The electron field determined from clinical scar underestimates the tumor bed in superior-inferior direction significantly and thereby underdosing the tissue at risk. The electron field obtained from surgical clips alone dose not cover the entire scar properly As a consequence, our technique, which combines the surgical clips and clinical scars in determining electron boost field, was proved to be effective in minimizing the geographical miss as well as normal tissue complications.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.91-98
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• 2014

Purpose : To compare the dosimetry for the left breast cancer treatment between three dimensional conformal radiation radiotherapy (3D-CRT) and Hybrid planning and to estimate usefulness of Hybrid planning Materials and Methods : Five patients with left breast cancer were included in the study. They were planned using several different radiotherapy techniques including: 1)open rectangular field, 2)tangential wedge-based field 3)field in field, 4)hybrid planning(energy, wedge combine). For each patient planning was using Light Speed RT-16 CT and PINNACLE planning system-ver.9.2. Hybrid plan was made using same system and using the same targets and optimization goals. We comparing the Homogeneity Index(HI), normal organs at the does-volume histogram(DVH) Results : In all plans, the Homogeneity Index(HI) of Hybrid planning was significantly better than other. Dose comparison of HI= 2D-RT:38.32, TW:38.32, FIF:29.22, HYBRID:30.57. 2D-RT, TW, FIF Hybrid$V_{75_-lung}$=112.33, 125.14, 121.3, 123.78. $V_{50_-lung}$=155.43, 159.62, 157.96, 159.06. $V_{25_-lung}$=199.86, 200.22, 198.65, 200.31. $V_{50_-heart}$=26.07, 27.1, 26.85, 27.17 $V_{30_-heart}$=33.71, 34.37, 34.15, 34.65 Conclusion : In summary, 3D-CRT, Hybrid planning techniques were found to have acceptableCTV coverage in our study. However the Hybrid planning increased radiation dose exposure to normal tissue. If you apply for treatment of inhomogeneity areas like lung, For best results will be achieved.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.439-452
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• 2014

This paper suggests the method to extend service area by using the transmit offset delay in T-DMB single frequency network (SFN). In general, synchronization of the transmit time of all site can be done by using the reference clock of GPS, which dose not reflect the details geographical characteristics and transmit specifications of each site. Applying the site-specific transmit offset delay, we could extend the service area of SFN T-DMB. Applying the transmit offset delay, it is found that the signal quality in the region of weak receive field strength was improved and upto 4~8 km service area expansion was achieved by satisfying the minimum field strength ($45dB{\mu}V/m$) recommended by the Korea Communications Commission (KCC). Site-specific offset delay was calculated considering the geographic service area characteristics, distribution of electric field strength between neighboring sites and site-specific service target area. Experiments were carried out in order to analyze impact of calculated offset delay on the T-DMB SFN and also to confirm that the offset delay extends T-DMB service coverage. The experiment was done in metropolitan T-DMB service areas.

• Journal of dental hygiene science
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• v.8 no.2
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• pp.65-71
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• 2008

The purpose of this study was to examine people's awareness of health insurance in a bid to help improve the management of dental health insurance coverage. The subjects in this study were 1,036 people who included experts in that field and medical consumers. The findings of the study were as follows: 1. In regard to the demographic characteristics of the expert group including gender and age, the female experts outnumbered the males, as the former accounted for 84.7 percent. And the experts in their 20s made up the largest age group, followed by the 30-39 age group and those in their 40s. As to the demographic characteristics of the medical consumers, the rates of the men and women stood at 49.8 percent and 50.2 percent respectively, which were similar. By age, the largest number of the medical consumers were in their 20s, followed by in their 30s and in their 40s. 2. Concerning opinions on the procurement of finance for health insurance, many respondents in both groups agreed that the health insurance coverage should be enlarged by securing more finance, and that items involved in the coverage should be prioritized again. Regarding a means of securing financial resources, the experts placed the most emphasis on extended budgetary support from the government, followed by establishing a social security system and budget compilation by local governments. The medical consumers attached the most importance to extended budgetary backing from the government, followed by budget compilation by local governments and determining contribution according to income level. 3. As for general view of the dental health insurance, the experts believed that the amounts of copayment and self-payment by the insured were appropriate(2.47), and they found the number of benefitted items to be proper(2.29) as well. The medical consumers thought that the benefit percentage of the dental health insurance in the overall health insurance budget was appropriate(2.26), and they also considered the number of benefitted items adequate(2.16). But this group didn't give a lot of marks to the appropriateness of those things. 4. As to perception about the dental health insurance, both groups took a similar view of it. Specifically, they felt the strong need for a dental health insurance system. In terms of satisfaction level, both groups were dissatisfied with it, and there was a strong tendency for them to be discontented with the health insurance coverage.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.61-70
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• 2000

Soil erosion in the hilly and mountainous uplands in the Daekwanryong area, Kangwon-Do, were investigated through a field plot experiment. The plot size was 15m long and 2.5m wide with the average slope of 12.5 percents. Soil erodibility factor (K), surface coverage (SC), soil aggregate percentage and wind erodibility (I) were evaluated in the mountainous soils under different management practices for corn and potato cultivations. Soil erodibility factor (K) was greater in upper part than in lower part of the plots. Surface coverage (SC) values ranged from 0.01 to 0.84 depending on the amounts of crop residues. Soils having a greater crop residue in surface were less subjected to soil erosion. SC values after corn harvest were 0.4 to 0.8, while those after potato harvest were 0.4 to 0.5, indicating potato might be better than corn for erosion control. Soil aggregate percentages of the experimental plots ranged from 49.7 to 79.8%. Those were higher in potato-cultivated plots with higher surface coverage, organic fertilizer treatment and contour tillage. Soil aggregate percentage of potato-cultivated plots was significantly correlated to crop residue coverage after harvest. The dried soil aggregate percentage, showing the ranges of 26.4 to 56.4%, were higher in the plots with the increased crop residue incorporation. Wind erodibility (I) of the soil was decreased with increasing surface coverage. When soil had 26.4% of the dried aggregate percentage, wind erodibility was estimated to be $183Mgha^{-1}$ which was equivalent to soil loss of $0.5Mg\ha^{-1}day^{-1}$.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.137-144
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• 2021

Purpose : The usability of X-Jaw split VMAT was evaluated by comparative analysis of the dose distribution between the treatment plan divided by X-Jaw and Full field VMAT treatment plan in left breast cancer treatment including supraclavicular lymph nodes. Materials and Methods : 10 patients with left breast cancer, including supraclavicular lymph nodes, were simulated using vacuum cushion, and 2 Full field Arc VMAT and 4 X-Jaw split Arc VMAT were planned The treatment plan was designed to include more than 95% of the Planning Target Volume (PTV) and to be minimally irradiated in the surrounding Organ at risk (OAR). Dose analysis of PTV and OAR was performed through dose volume histogram (DVH). Results : The Full field VMAT treatment plan and the X-Jaw split VMAT treatment plan of 10 patients were expressed as average values and compared. The difference between the two treatment plans was not large, with a Conformity index (CI) of 1.05±0.04, 1.04±0.03, and a Homogeneity index (HI) of 1.07±0.008, 1.07±0.009. For OAR, V5 in the left lung is 56.1±6.50%, 50.4±6.30%, and V20 is 20.0±4.15%, 13.52±3.61%. Compared to Full field VMAT, V5 decreased by 10.0% V20 by 32.6% in X-Jaw split VMAT. The V30 of the heart is 3.68±1.85%, 2.23±1.52%, and the Mean dose is 8.93±1.65 Gy, 7.67±1.52 Gy. In the X-Jaw split VMAT, V30 decreased by 39.3% and the Mean dose decreased by 14.1%. The left lung and heart, which are normal tissues, were found to have a statistical significance of that p-value is less than 0.05. Conclusion : In the case of left breast cancer treatment, which includes Supraclavicular lymph nodes with a large PTV volume and a length of X Jaw of 15 cm or more, the X-Jaw split VMAT shows improved dose distribution, which can reduce radiation dose of OAR such as lungs and heart, while maintaining similar PTV coverage with HI and CI equivalent to Full field VMAT. It is thought to be effective in reducing radiation complications.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.72.3-72.3
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• 2015

We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star forming (SF) galaxies based on the AKARI's NEP-Wide Survey data. We utilized a combination of the NEP-Wide point source catalogue containing a large number (114,000) of infrared (IR) sources distributed over the wide (5.4 sq. deg) field and spectroscopic redshift (z) data for 1790 selected targets obtained by optical follow-up surveys with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2{\sim}24{\mu}m$ wavelength coverage and the spectroscopic redshifts for sample galaxies enable us to derive accurate spectral energy distributions (SEDs) in the mid-infrared. We carried out SED-fit analysis and employed 1/Vmax method to derive the mid-IR (e.g., $8{\mu}m$, $12{\mu}m$, and $15{\mu}m$ rest-frame) luminosity functions. Our results for local galaxies from the NEP region generally consistent with various previous works for other fields over wide luminosity ranges. The comparison with the results of the NEP-Deep data implies the luminosity evolution from higher redshifts towards the present epoch. We attempted to fit our derived LFs to the double power-laws and present the resulting power indices. We also examined the correlation between mid-IR luminosity and total IR luminosity.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.145-146
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• 2012

We present the results from B-, R-, I-, J- and H-band observations of the NEP-Wide survey field. The NEP-Wide survey is an AKARI survey of the North Ecliptic Pole covering ~ 5 square degrees area. Our optical/NIR imaging supports the AKARI IR imaging data by providing a crucial coverage in the optical/NIR. The optical data were obtained in 2007 using the 1.5 m telescope and SNUCAM at Maidanak Observatory, Uzbekistan. The NIR data were obtained in 2008 with FLAMINGOS on the KPNO 2.1 m telescope. We used IRAF, SExtractor, SCAMP, and SWarp for reducing the raw data, I-band fringe pattern removal, astrometry, standard photometry calibration, and source detection. Our optical-NIR data reach the depths of B ~ 23.4, R ~ 23.1, I ~ 22.3, J ~ 21.05, and H ~ 20.64 AB mag at 5-sigma. Here, we present the astrometric accuracy, galaxy number counts, completeness, and reliability, as well as redshift tracks of some normal galaxies and quasars on the B - R vs. R - I color-color diagram. The photometric data are being used for identifying optical counterparts of the IR data provided by AKARI, studying their SEDs, and selecting interesting objects for spectroscopic follow-up studies.

• Journal of IKEEE
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• v.16 no.3
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• pp.251-257
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• 2012

In this paper, low power on-channel DTV repeater is implemented to improve the fringe area of terrestrial DTV broadcasting services and its effectiveness is verified by field trials. System requirements of on-channel repeater are drive from received signal model and gain transfer model. Implemented on-channel DTV repeater has coverage of about 1km with 10mW/MHz output power. Experimental results show that implemented system can effectively improve small/medium size DTV fringe areas in Korea.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.177-187
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• 2000

Measurements of temperature fields and film-cooling effectiveness have been conducted for a shower-head film cooling on the leading edge of a blunt body, which simulates a first-stage turbine stator. In this study, three injection cases are employed for an average blowing ratio based on freestream velocity, M, of 0.5, 1.0 and 1.5. Two (Case 1), four (Case 2) and six (Case 3) rows of normal holes are symmetrically drilled on the three tested circular-cylinder leading edges. The measurements show that regardless of M, the film-cooling effectiveness increases as the injection row is situated at farther downstream location. In Case 1, the film-cooling effectiveness is highest for M = 0.5 and lowest for M = 1.5. On the contrary, in Case 3, the film-cooling effectiveness is highest for M = 1.0 and lowest for M = 0.5. When M = 0.5, the film coverage by the first row of the injection holes deteriorates as the number of the injection row increases. In particular, the film-cooling effectiveness due to the injection through the first row of the holes in Case 3, has a nearly zero value.