• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2816-2821
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• 2008

This paper investigates the flow field and organism concentration in a UV disinfection channel in which vertical ultraviolet lamps are arranged in a staggered configuration. Turbulence is described by low Reynolds number ${\kappa}-{\varepsilon}$ turbulence model and standard ${\kappa}-{\varepsilon}$ turbulence model, respectively. P-1 method has been employed to solve the radiative transfer equation. The obtained incident radiation is used to compute the inactivation term in the species equation. The CFD results are in good agreement with the existing experimental data for the UV channel. For the flow field, the low-Reynolds number ${\kappa}-{\varepsilon}$ model is superior to the standard ${\kappa}-{\varepsilon}$ model. The approach velocity has a significant effect on the disinfection efficiency. The organism concentration at the outlet decreases fast to a low inlet velocity.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.295-300
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• 2018

Net radiation is the total amount of radiation energy used as a heat flux for the Earth's energy cycle, and net radiation from the surface is an important factor in areas such as hydrology, climate, meteorological studies and agriculture. It is very important to monitoring the net radiation through remote sensing to be able to understand the trend of heat island and urbanization phenomenon. However, net radiation estimation using only remote sensing data is generally causes difference in accuracy depending on cloud. Therefore, in this paper, we retrieved and monitored high resolution surface net radiation at 1 hour interval in Eunpyeong New Town where urbanization using Communication, Ocean and Meteorological Satellite (COMS), Landsat-8 satellite and Computational Fluid Dynamics (CFD) model data reflecting the difference in building height. We compared the observed and estimated net radiation at the flux tower. As a result, estimated net radiation was similar trend to the observed net radiation as a whole and it had the accuracy of RMSE $54.29Wm^{-2}$ and Bias $27.42Wm^{-2}$. In addition, the calculated net radiation showed well the meteorological conditions such as precipitation, and showed the characteristics of net radiation for the vegetation and artificial area in the spatial distribution.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.2
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• pp.109-129
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• 1995

Many patients with malignancies of the head and neck undergo radiation therapy, either as the only method of treatment or in combination with surgery. Radiation therapy has great effect in the case of fairly advanced malignancies which can't be operated radically. But the complication of radiation therapy arise because of damage to the peri- and operated area. It is fully known that irradiated tissue shows retarded healing process in the skin, mucosa and especially vascuslar tissue. The purpose of this study was to observe the healing process of irradiated free or island flap after operation. As Experimental Models, Femoral arterial and venous anastomosis (Group 1), Epigastric-island flap (Group 2) and free Epigastric falp(Group 3) with irradiated postoperative 24 hrs were made on 30 rats/group. As Control Model(Group 4), Free Epigastric flap was not irradiated after operation was chosen on 30 rats. The amount of irradiation was single fraction of 20 Gy using as linear megavoltage accelerator. Difference between Experimental and Control group was evaluated by the method of clinical examination, histopatholoical findings, biochemical analysis and DNA activity at postoperative 1, 3, 7, 14 and 28 days. The results were as follows, 1. Skin color and new epithelization in group 2 and 3 was similar to control group clinically. 2. Postoperarive patency of femoral artery and vien showed 5% and 22% of ischemity. 3. The externa, media and intima of irradiated femoral artery and vein were similar to control group histopathlogically. 4. Granulation and collagen tissue accumulation of irradiated groups were more active due to degenerative and fibrotic changes than control group at postoperative 7 days histopathologically. 5. The hydroxyproline content of all experimental groups were reduced till 14 days and the group 2 was most prominent at postoperative 7 and 28 days(p<0.05). 6. DNA activities of all groups were reduced till 3 days, but begun to recover at 7 days and more activities in control group than irradiated group(p<0.05). Based on the above results, the clinical healing process of free flaps with irradiated postoperative 24 hrs little difference from control group without complications.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.941-946
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• 2008

Single-minded 1 gene (SIM1) is a homolog of Drosophila SIM1 gene which plays a key role in the midline cell lineage of the central nervous system and is implicated in the regulation of feeding behavior and obesity in the human and mouse. In this study, porcine SIM1 gene was firstly mapped to chromosome 1p13 using radiation hybrid (RH) mapping and two polymorphisms were detected at position 607 (A/G) in SIM1 intron7 and position 780 (C/T) in SIM1 exon8. The last substitution was genotyped in a 364 F2 animal-population and an association analysis of these genotypes was performed with growth, carcass and meat quality traits by the statistical animal model. The results showed the significant influence of the SIM1 genotype on growth (p<0.05): live weight at birth, later period of growth and average daily gain; and effects on carcass composition (p<0.05): weight of head and buck kneed foreleg, backfat depth, loin eye area, carcass leaf fat and ham fat weights; and traits related to intramuscular fat content (p<0.05).

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.280-288
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• 2009

This study is to design and produce a detailed model for volume variety of three dimensional reconstruction images and to evaluate the changes of volume, area and the length of the model in the process of the reconstruction of RTP system. CT simulation was operated at the thickness of 1.25, 2.5, 5, 10mm and average, standard deviation of scan direction(X), thickness(Y), table movement direction(Z), area(A), and volume(V) of the three dimensional volume rendering, were measured according to the shape and thickness of the phantoms. As a result, at the thickness of 1.25, 2.5min, the phantom's shape decreased maximum 0.13cm(p<0.05) to the direction of X, Y, Z and length, area, volume decreased 0.1cm, $0.8cm^2$, $3.99cm^3$ which led to an approximate image of the phantoms. However, at the thickness of 5, 10mm, the phantom of the original form decreased maximum 0.58cm(p<0.05) and volume, area, length decreased maximum 0.45cm, $8.21cm^2$, $11.03cm^3$. Volume varieties according to the thickness and shape of the phantoms have occurred diversely, when CT simulation was operated, and it is considered that a clinically appropriate volume rendering can be obtained only when the thickness is below 3mm.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.225-231
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• 1998

Purpose : To determine whether TNF-$\alpha$ increases the antitumor effect of radiotherapy in murine syngeneic tumor system. Materials and Methods : Syngeneic murine tumors of MCa-K or MCa-4 (mammary carcinoma), OCa-I (ovarian carcinoma), or HCa-I(hepatocarcinoma were grown in hind legs of C3Hf/HeJ mice. When tumors were grown to 6 mm in mean diameter mice were treated with TNF-$\alpha$, radiation, or combination of the both. Gamma-radiation was given as a single dose of 30 Gy for HCa-I and 15 Gy for other tumors using Cobalt-60 teletherapy unit. A novel TNF-$\alpha$ mutein developed in Korea, was intraperitoneally administered daily at a dose of 10 ug per mouse for 7 days. In combination of radiation and TNF-$\alpha$, the drug was started 1 hour after radiation. Tumor growth delay assay was used to measure the tumor response to the treatment. Results : Among 4 tested tumors, TNF-$\alpha$ alone showed significant antitumor activity in MCa-K and OCa-I tumors, which showed absolute growth delay (AGD) of 5.0 days and 6.5 days, respectively. In combination with radiation, TNF-$\alpha$ showed significant delay of AGD (41.1 days) in OCA-I compared to AGDs of TNF-$\alpha$ alone and radiation, i.e., 6.5 days and 26.9 days, respectively(p<0.05). Enhancement factor was 1.29 in OCa-I, which showed supraadditive effect. TNF-$\alpha$ did not show significant delay of AGDs in the remaining 3 tumors compared to AGDs of TNF-$\alpha$ alone and radiation. Conclusions: TNF-$\alpha$ alone showed antitumor effects in MCa-K and OCa-I. In combination with radiation, TNF-$\alpha$ acted in supraadditive way in OCa-I only. The results of this study imply that the combination of TNF-$\alpha$ and radiation has different therapeutic potential depending on tumor model and further study is advocated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.23-32
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• 2008

In the VHF range, active antennas are widely used for wideband applications due to their small size. Active antenna consists of antenna elements and amplifiers, which are directly connected to each other. Gain and noise-figure characteristics are very important for good sensitivity performance, because it is located at the front end of a receiving system. In this study, we developed an active dipole antenna with 5:1 bandwidth(100${\sim}$500 MHz), which consists of a dipole antenna and a P-HEMT amplifier. To obtain required performances, the antenna and the amplifier should be designed simultaneously. In order for that, we introduced an equivalent port concept to model the 1-port dipole antenna as an equivalent 2-port system. Using the proposed equivalent port, the performance of the active dipole antenna was simulated by the ADS. In order to measure the gain and noise-figure characteristics of the antenna, we utilized the same concept of the two-port equivalent impedance model. The measurement results for typical gain, NF and VSWR in the required frequency band were 8dBi, 9dB and 1.7:1, respectively. The radiation patterns at the principal planes were same as the typical radiation pattern of a dipole antenna. By comparing the simulation results with measured ones, it is confirmed that the proposed methods works well.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.263-264
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• 1996

We have solved the radiative transfer problem using a Sobolev approximation with an escape probability method in case of the supersonic expansion of a stellar envelope to an ambient medium. The radiation from the expanding envelope turns out to produce a P-Cygni type profile. In order to investigate the morphology of the theoretical P-Cygni type profile, we have treated $V{\infty},\;V_{sto},\;{\beta}$ (parameter for the velocity field), M and $\epsilon$ (parameter for collisional effect) as model parametrs. We have found that the velocity field and the mass loss rate affect the shapes of the P-Cygni type profiles most effectively. The secondarily important factors are $V{\infty},\;V_{sto}$. The collisional effect tends to make the total flux increase but not so .much in magnitude. We have infered some physical parameters of 68 Cyg, HD24912, and $\xi$ persei such as V$\infty$, M from the model calculation, which shows a good agreement with the observational results.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.91-99
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• 1999

Propose : This study was performed to find out the prognostic factors affecting local control, survival and disease free survival rate in nasopharyngeal carcinomas treated with chemotherapy and radiation therapy. Materials and Methods : We analysed 47 patients of nasopharyngeal carcinomas, histologically confirmed and treated at Chonnam University Hospital between July 1986 and June 1996, retrospectively. Range of patients' age were from 16 to 80 years (median; 52 years). Thirty three (70$\%$) patients was male. Histological types were composed of 3 (6$\%$) keratinizing, 30 (64$\%$) nonkeratinizing squamous cell carcinoma and 13 (28$\%$) undifferentiated carcinoma. Histoiogicai type was not known in 1 patient (2$\%$). We restaged according to the staging system of 1997 American Joint Committee on Cancer Forty seven patients were recorded as follows: 71: 11 (23$\%$), T2a; 6 (13$\%$), T2b; 9 (19$\%$), 73; 7 (15$\%$), 74: 14 (30$\%$), and NO; 7 (15$\%$), Nl: 14 (30$\%$), N2; 21 (45%), N3: 5 (10%). Clinical staging was grouped as follows: Stage 1; 2 (4$\%$), IIA: 2 (4$\%$), IIB; 10 (21$\%$), III; 14 (30$\%$), IVA; 14 (30$\%$) and IVB; 5 (11$\%$). Radiation therapy was done using 6 MV and 10 MV X- ray of linear accelerator. Electron beam was used for the Iymph nodes of posterior neck after 4500 cGy. The range of total radiation dose delivered to the primary tumor was from 6120 to 7920 cGy (median; 7020 cGy). Neoadjuvant chemotherapy was performed with cisplatin +5-fluorouracil (25 patients) or cisplatin+pepleomycin (17 patients) with one to three cycles. Five patients did not received chemotherapy. Local control rate, survival and disease free suwival rate were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of survival rates between groups. multivariate analysis using Cox proportional hazard model was done for finding prognostic factors. Results: Local control rate was 81$\%$ in 5 year. Five year survival rate was 60$\%$ (median survival; 100 months). We included age, sex, cranial nerve deflicit, histologic type, stage group, chemotherapy, elapsed days between chemotherapy and radiotherapy, total radiation dose, period of radiotherapy as potential prognostic factors in multivariate analysis. As a result, cranial none deficit (P=0.004) had statistical significance in local control rate. Stage group and total radiation dose were significant prognostic factors in survival (P=0.000, P=0.012), and in disease free survival rates (P=0.003, P=0.008), respectively. Common complications were xerostomia, tooth and ear problems. Hypothyroidism was developed in 2 patients. Conclusion : In our study, cranial none deficit was a significant prognostic factor in local control rate, and stage group and total radiation dose were significant factors in both survival and disease free survival of nasopharyngeal carcinoma. We have concluded that chemotherapy and radiotherapy used in our patients were effective without any serious complication.

• Journal of Preventive Medicine and Public Health
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• v.31 no.1 s.60
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• pp.91-103
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• 1998

Under experimental conditions, UVB radiation, a type of ultra violet radiation, has shown to .elate with the occurrence of skin erythema (sun-burn) in human and skin cancer in experimental animal. Cumulative exposure to UVB is also believed to be at least partly responsible for the 'aging' process of the skin in human. It has also been observed to have an effect of altering DNA (deoxyribonucleic acid). UVB radiation is both an initiator and a promoter of non-melanoma skin cancer. Meta-analysis is a new discipline that critically reviews and statistically combines the results of previous researches. A recent review of meta-analysis in the field of public health emphasized its growing importance. Using a meta-analysis in this study, we explored more reliable dose-response relationships between UVB radiation and skin cancer incidence. We estimated skin cancer incidence using measured UVB radiation dose at a local area of Seoul (Shin chou-dong). The studies showing the dose-response relationships between UVB radiation and non-melanoma skin cancer incidence were searched and selected for a meta-analysis. The data for 7 reported epidemiological studies of three counties (USA, England, Australia) were pooled to estimated the risk. We estimated rate of incidence change of skin cancer using pooled data by meta-analysis method, and exponential and power models. Using either model, the regression coefficients for UVB did not differ significantly by gender and age. In each analysis of variance, non-melanoma skin cancer incidence after removing the gender and age and UVB effects was significant (p>0.01). The coefficients for UVB dose were estimated $2.07\times10^{-6}$ by the exponential model and 2.49 by the power model. At a local area of Seoul (Shinchon-Dong), BAF value were estimated 1.90 and 2.51 by the exponential and power model, respectively. The estimated BAP value were increased statistical power than that of primary studies that using a meta-analysis method.