• Journal of radiological science and technology
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• v.37 no.4
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• pp.341-348
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• 2014

Wedge filter could use to increase the dose distribution at the hot dose regions. We evaluated dose discrepancy at surface and build region in the infield and outfield that Metal Wedge (MW) and Enhance Dynamic Wedge (EDW) were interact with photon. In this paper, we used Gafchromic EBT3 film that had excellent spatial resolution, composed the water equivalent materials and changed the optical density without development. The set up conditions of linear accelerator were fixed 6 MV photon, 100 cm SSD, $10{\times}10cm^2$ field size and were irradiated 400 cGy at Dmax. The dose distribution and absorbed dose were evaluated when we compared the open field with $15^{\circ}$, $30^{\circ}$, $45^{\circ}$ metal wedge and enhanced dynamic wedge. A $15^{\circ}$ metal wedge could increase the surface and build up region dose than using a $15^{\circ}$ enhanced dynamic wedge. A $30^{\circ}$ metal wedge could decrease the surface and build up region dose than using a $30^{\circ}$ enhanced dynamic wedge. A $45^{\circ}$ metal wedge could decrease by large deviation the surface and build up region dose than using a $15^{\circ}$ enhanced dynamic wedge. The dose of penumbra region at outfield were increased on the thick side but were decreased on the thin side. It could be decrease the surface dose and build up region dose, if the metal wedge filters were properly used to make a good dose distribution and not closed the distance of surface.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.353-368
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• 2016

This study surveyed the diversity and distributional characteristics of benthic macroinvertebrates and freshwater fish during the period from April to October, 2015 in Seonun Mountain Provincial Park. As a result, a total of 78 species of benthic macroinvertebrates belonging to 50 families, 16 orders, and four phyla were observed in Seonun stream; additionally, 25 species of freshwater fish belonging to six families were identified in all the investigated sites. Among benthic macroinvertebrates, Ephemeroptera(13 spp.: 22.81%) was the largest group in terms of species richness. In the FFGs, gathering-collectors(30 spp.: 36.14%) were relatively larger as represented by Ephemeroptera that usually inhabit fast flowing streams. In the HOGs, clingers(23 spp.: 29.49%) and burrowers(17 spp.: 21.79%) were the dominant groups. For both EPT ratio and ESB index, site 8 appeared to be the highest with 44.44% and 72 marks respectively, while the sites 4 and 9 showed relatively lower rates and indices. According to the results of evaluation, site 8 needs to be designated as the highest protection area while the sites 4 and 9 may be designated as target areas for preferential improvement. According to the analysis of fish community, the dominant species was Zacco teminchkii(333 inds.: 36.80%), and the dominant index was the lowest(0.24) and diversity index was the highest(1.81) at site 8, which therefore represents a stable freshwater fish community. In this survey, six Korean endemic species were identified: Ephemera separigata, Neoperla coreensis, Rhodeus uyekii, Squalidus gracilis majimae, Microphysogobio yaluensis, and Iksookimia koreensis. Also, three species belonging to the management of exportable group(Davidius lunatus, E. separigara, N. coreenis) were observed. Two habitat specific species: Thraulus grandis and Anguilla marmorata, were found for the first time in Gochang area and marked on the Korean distribution map through discussion.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.4
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• pp.10-25
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• 2015

The purpose of this research is to investigate the reality behind Jeongjo's enjoyment of the palace garden. If I were to summarize the results of this research, they are as follows: First, The 'Sanghwajoeoyeon(賞花釣魚宴)' has the differentiation which decided and regularized the rules and the regulations with the annual meetings for the Kyujanggak(奎章閣). Jeongjo had held the events five times. Second, The 'Seshimdae(洗心臺) Excursion' is based on the tragic personal history of Jeongjo. There were four events. Third, Jeongjo had enjoyed the 'viewing of the waterfall(觀瀑)' of the Okryucheon(玉流川) where a lot of the water overflows right after it rains. This is worth the special mention with regard to the point that it is a temporary landscape and not an usual landscape. Fourth, As an event for the military officers, the 'Seoljungryonghohwe(雪中龍虎會)' was held seven times. This event had been held in the middle of the winter. And each of the attendees skewered a pheasant and roasted and ate it. Also, it emphasized the sovereign and the subjects being the partners of the joys and the sorrows by giving the alcoholic drinks and the music. Fifth, Jeongjo had consoled the hard work by the civilian subjects either by holding the brazier feast(煖爐會) in the winter or by granting the alcoholic drinks and the foods according to the historical facts of the brazier feasts. Sixth, Jeongjo was good at archery and enjoyed it. During the period of his reign, Jeongjo held twice Yeonsarye(燕射禮). Seventh, Jeongjo soothed his desire to get out of the busy everyday life at the royal palace garden. While appreciating the natural landscape of the backyard, he was awakened of the meaning of the Book of Changes(周易) in which all the things had been created and changed. Eighth, At the royal palace garden, Jeongjo actively prepared the place for enjoyment by the sovereign and the subjects together. It is judged that this is because, in order to materialize his political ideals, the support by all the subjects who had been close was needed. The limitation of this research is the fact that the research had been proceeded with limited to the translations, among the many old writings related to Jeongjo. With the accumulation of the excavations of the new thoughts and of the results of the translations, the researches that are deeper will be needed.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.2
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• pp.89-102
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• 2015

This study contemplates the tendency of the examination questions for History of Korean Landscape Architecture. The study targets the questions of 'Landscape Architecture History' which has been set in the written test for National Qualification Test of a landscape engineer for recent 10 years from 2005 to 2014 and derives analyzable items based on the guidelines of question-setting presented by Human Resources Development Service of Korea. The results of the study are drawn as follows. First, among 5 areas composing Landscape History, the proportion of Korean Landscape questions is getting increased while that of Western ones is decreasing. Second, about 30 traditional trees and 11 types of traditional landscape elements including traditional facilities were shown in Korean Landscape questions. Besides, history, geographic, practical science, horticulture, anthology books and the 25 tradition landscape-related historic documents categorized as the garden painting data were found. And the kings from ancient era to Choseon Dynasty who were associated with the time of palace garden building, the builders or owners of the villas, the authors of the document and Chinese scholars also appeared. Third, there were no the questions of prehistoric times and Balhae Kingdom, whereas those of Choseon Dynasty were dominantly focused. Among the traditional sites of Choseon Dynasty, Byeolseo(villas) were set most, followed by Dosung or Gung-gweol(castle towns or palaces), houses, Nu Jeong Dea(pavilions) and Seowon(local schools) in order. Nak-an eupseong and Yong-ju sa were the only cases for a castle town and a temple each. Fourth, being associated with tradition spaces, the questions asked for understanding the detailed contents of time of sites' construction, builders, location features, building structures, ground plan types and the components s of garden. In addition, as a result of checking whether traditional landscape sites were shown in the set questions in 9 Korean Landscape textbooks, Dongchundang, Pungamjeonsa, Simgogseowon did not appeared. As a result of reviewing the tendency of the examination questions for History of Korean Landscape Architecture, the questions which ask minor facts without generality and which include difficult information and site uncomprehended in the textbook should be reconsidered.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.1
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• pp.17-25
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• 2016

Purpose : The purpose of this study is to evaluate the variability of tumor motion and respiration pattern in lung cancer patients undergoing Stereotactic Body RadioTherapy(SBRT) by using On-Board imager (OBI) system and Real-time Position Management (RPM) System. Materials and Methods : This study population consisted of 60 lung cancer patient treated with stereotactic body radiotherapy (48 Gy / 4 fractions). Of these, 30 were treated with gating (group 1) and 30 without gating(group2): typically the patients whose tumors showed three-dimensional respiratory motion > 10 mm were selected for gating. 4-dimensional Computed Tomography (4DCT). Cone Beam CT (CBCT) and Fluoroscopy images were used to measure the tumor motion. RPM system was used to evaluate the variability of respiration pattern on SBRT for group1. Results : The mean difference of tumor motion among 4DCT, CBCT and Fluoroscopy images in the cranio-caudal direction was 2.3 mm in group 1, 2. The maximum difference was 12.5 mm in the group 1 and 8.5 mm in group 2. The number of treatment fractions that patient's respiration pattern was within Upper-Lower threshold on SBRT in group 2 was 31 fractions. A patient who exhibited the most unstable pattern exceeded 108 times in a fraction Conclusion : Although many patients in group 1 and 2 kept the reproducibility of tumor motion within 5 mm during their treatment, some patients exhibited variability of tumor motion in the CBCT and Fluoroscopy images. It was possible to improve the accuracy of dose delivery in SBRT without gating for lung cancer patient by using RPM system.

• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1173-1185
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• 2019

We, for the first time, retrieved sulfur dioxide (SO₂) vertical column density (VCD) in industrial and volcanic areas from TROPOspheric Monitoring Instrument (TROPOMI) using the Principle component analysis(PCA) algorithm. Furthermore, SO₂ VCDs retrieved by the PCA algorithm from TROPOMI raw data were compared with those retrieved by the Differential Optical Absorption Spectroscopy (DOAS) algorithm (TROPOMI Level 2 SO₂ product). In East Asia, where large amounts of SO₂ are released to the surface due to anthropogenic source such as fossil fuels, the mean value of SO₂ VCD retrieved by the PCA (DOAS) algorithm was shown to be 0.05 DU (-0.02 DU). The correlation between SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm were shown to be low (slope = 0.64; correlation coefficient (R) = 0.51) for cloudy condition. However, with cloud fraction of less than 0.5, the slope and correlation coefficient between the two outputs were increased to 0.68 and 0.61, respectively. It means that the SO₂ retrieval sensitivity to surface is reduced when the cloud fraction is high in both algorithms. Furthermore, the correlation between volcanic SO₂ VCD retrieved by the PCA algorithm and those retrieved by the DOAS algorithm is shown to be high (R = 0.90) for cloudy condition. This good agreement between both data sets for volcanic SO₂ is thought to be due to the higher accuracy of the satellite-based SO₂ VCD retrieval for SO₂ which is mainly distributed in the upper troposphere or lower stratosphere in volcanic region.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.178-182
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• 2003

Purpose : Brain tumors are the second most common tumor in childhood, and medulloblastomas comprise 15-25% of brain tumors. The well known prognostic factors are age at diagnosis, stage of disease, and extent of surgical excision. In this study, we analysed the prognostic factors in patients who received chemotherapy after excision. Methods : We reviewed the medical records of 61 patients who received chemotherapy among the 94 patients who were diagnosed and treated between Jan 1985 and Sep 2001 in the Department of Pediatrics and Neurosurgery at Severance Hospital. Results : Among the total survival rate of patients who underwent chemotherapy, the 3-yr progression-free survival rate was $66.5{\pm}6.3%$ and the 15-yr progression-free survival rate was $60.3{\pm}6.7%$. The progression-free survival rate for patients with age at diagnosis over 3 yrs old and under 3 yrs old, was $64.5{\pm}7.7%$ and $48.2{\pm}12.9%$ respectively and there was no statistically significant difference. The survival rate of the high vs low risk group by staging was $72.7{\pm}10.5%$ and $54.6{\pm}8.3%$ respectively, and there was no significant difference. The survival rate of patients with total removal vs subtotal removal was $65.8{\pm}11.8%$ and $56.8{\pm}8.2%$ respectively, showing no statistical difference. Conclusion : The reason there is no difference in survival rate according to the traditional prognostic factors is that chemotherapy has improved not only the total survival rate but also the survival rate in patients with poor traditional prognostic factors. So, sufficient removal of tumor followed by proper chemotherapy and radiotherapy is an important factor which influences the survival rate of medulloblastoma patients.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.1
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• pp.24-35
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• 2016

To assess the relationship between environmental factors and seasonal phytoplankton community structure, we investigated abiotic and biotic factors in Ulsan Bay, Korea. We divided the bay into two areas based on geographical characteristics and compared the difference in each factor between inner and outer bay with t-test statistics. As a result, temperature in the outer bay was higher than that of the inner bay during winter (t = -5.833, p < 0.01) and autumn (p > 0.05). However, opposite trend was observed during spring (t = 4.247, p < 0.01) and summer (t = 2.876, p < 0.05). Salinity was significantly lower in the inner bay than in the outer bay in winter, spring, and summer (p < 0.01). However, the salinity was not significantly different between the inner and the outer bay in the autumn (p > 0.05). In particular, high nutrient concentration was observed in most stations during winter season due to vertical well mixing. The nutrient concentration was significantly higher in surface layers of inner bay after rainfall, particularly in the summer. The relative contribution (approximately 70%) of < $20{\mu}m$ (nano and pico) size phytoplankton was increased in all seasons with continuously low nutrients from the offshore water due to their adaption to low nutrient without other large competitors. Interestingly, high population of Eutreptiella gymnastica was kept in the inner bay during the spring and summer associated with high DIN (nitrate+nitrite, ammonium) after river discharge following rainfall, suggesting that DIN supply might have triggered the increase of Eutreptiella gymnastica population. In addition, high density of freshwater species Oscillatoria sp. and Microcystis sp. were found in several stations of the inner bay that were provided with large amounts of freshwater from the Tae-wha River. Diatom and cryptophyta species were found to be dominant species in the autumn and winter. Of these, centric diatom Chaetoceros genus was occupied in the outer bay in the autumn. Cryptophyta species known as opportunistic micro-algae were found to have high biomass without competitors in the inner bay. Our results demonstrated that Ulsan Bay was strongly affected by freshwater from Tae-wha River during the rainy season and by the surface warm water current from the offshore of the bay during dry season. These two external factors might play important roles in regulating the seasonal phytoplankton community structures.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.21-28
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• 2006

This paper presents both experimental and analytical studies for the development of an ECC(Engineered Cementitious Composites) using ground granulated blast furnace slag(slag). This material has been focused on achieving moderately high composite strength while maintaining high ductility, represented by strain-hardening behavior in uniaxial tension. In the material development, micromechanics was adopted to properly select optimized range of the composition based on steady-state cracking theory and experimental studies on matrix, and interfacial properties. A single fiber pullout test and a wedge splitting test were employed to measure the bond properties of the fiber in a matrix and the fracture toughness of mortar matrix. The addition of the slag resulted in slight increases in the frictional bond strength and the fracture toughness. Subsequent direct tensile tests demonstrate that the fiber reinforced mortar exhibited high ductile uniaxial tension behavior with a maximum strain capacity of 3.6%. Both ductility and tensile strength(~5.3 MPa) of the composite produced with slag were measured to be significantly higher than those of the composite without slag. The slag particles contribute to improving matrix strength and fiber dispersion, which is incorporated with enhanced workability attributed to the oxidized grain surface. This result suggests that, within the limited slag dosage employed in the present study, the contribution of slag particles to the workability overwhelms the side-effect of decreased potential of saturated multiple cracking.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.239-249
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• 1999

In orthognathic surgery to obtain proper functional and esthetic form after skeletal discrepancy treatment, precise diagnosis and treatment plan are essential. Especially in two jaw surgeries that have serious upper and lower jaw problems, maxilla and mandible are arranged in three dimensions. Based on the maxillary rearrangement, mandibular sagittal and transverse positions are determined, and thus new occlusal plane is established. The object of this study is to evaluate the stability of the indiviual ideal occlusal plane based on the architectural and structural craniofacial analysis of Delaires. The subjects of this study were 48 patients who underwent two jaw surgeries, and they were equally divided into two groups, A and B. A group was operated with ideal occlusal plane and B group was not. Two groups were compared at the preoperative, immediate postoperative (average 4.3days), and long-term postoperative (average 1.3years) lateral cephalometric radiographs. The following results were obtained: 1. ANS was lower than that of PNS for both A and B after the surgery. That is, maxilla and mandible are rotated in posterior and superior direction. 2. Significances were found between $T_2$ and $T_3$ for both A and B are HRP-Me at vortical measurements, articular angle(p<0.01), gonial angle(p<0.01), and Mn. plane angle(p<0.05) at angular measurement. Mn. plane angle is increased at HRP-Me is decreased for both A and B. 3. There is no significance in skeletal stability aster the surgery between group A and B. 4. Horizontal movements of B and Pog by surgery have statistically significant inverse correlations with horizontal relapse of B and Pog, and vertical relapse of PNS, as well as Mn. Plane angle, and gonial angle after the surgery.