• Title/Summary/Keyword: Quality system

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Composting of the Pig Manure Used with the Ceramic Biocarrier (복합세라믹 담체를 이용한 돈분 퇴비화 연구)

  • Hwang, Joon-Young;Lee, Jong-Eun;Chang, Ki-Woon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.11 no.2
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    • pp.110-116
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    • 2003
  • This study was executed to evaluate the utilization and efficiency of the ceramic biocarrier as the promoter of decomposing on the organic matters for the composting using with pig manure by analyzing of the physico-chemical properties during composting. The treatments of this experiment were consisted of the control(C),microorganism(M), M with natural zeolite(M+Z), M with synthesized zeolite(M+SZ), and M with ceramic biocarrier(M+CZ). The process term of composting was conducted for 30days in the rapidly fermented machine(as pilot system). The results of the physico-chemical properties of the composts were as follows. The changes of temperature during composting was not relative with the microorganism and zeolite materials used in the composts. At all of the treatments were similar to changing of temp. from the initial stage to the final stage. But the added microorganism treatments were higher than control. And the entire pH value of treatments were appeared the same that above temperature result, also the M+CZ and M+SZ treatment among the treatment were higher. At the results of T-C, T-N and C/N ratio, in case of T-C value, the M+CZ treatment was highly more decreased than others. However at the T-N value, there were not the differences from the each treatment. And the C/N ratio was changed according to the changes of T-C and T-N value. Especially, at the M+CZ aud M+SZ treatments were remarkably reduced by about 21.4-23.3 value. In the result of G.I for evaluating of the compost humidity, the M+CZ and M+SZ treatments were close up approximately 110 value compared with the control(G.I value 100). Therefore, the examined ceramic biocarrier amended with compost-promoting-bacteria could be applied to the production of many high quality fertilizers. It is also expected that the results of this researches could be applied to the recycle of the organic wastes based on the experimental results of ceramic biocarrier and compost-promoting-bacteria application.

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Changes of Physico-chemical Characteristic on Swine Manure Using Different Suction Strength in Composting System (돈분 퇴비화 시 공기 흡입 강도에 따른 이화학적 특성변화)

  • Lee, Dong-Jun;Kim, Jung Kon;Jeong, Kwang-Hwa;Kawg, Jung-Hoon;Ravindran, B.;Lee, Ji-Woong
    • Journal of the Korea Organic Resources Recycling Association
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    • v.25 no.2
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    • pp.59-67
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    • 2017
  • The aim of this experiment was to investigate the effect of air suction rate (SR) during the composting process of swine manure mixed with sawdust used as a bulking agent. In the 25 L composting reactors, the suction rate (SR) was at four different treatment levels (100%, 200%, 300%, 400%), and were fixed on the based on constant aeration rate into the composting mixtures. The temperature reached to thermophilic phase within 2 days and it was maintained up to the $5^{th}$ day of the composting process in all reactors and then gradually decreased to room temperature at the end of the composting process. The moisture content (MC, %) of the initial mixtures was 64.27%, and it was reduced to 38.4, 33.08, 14.59 and 11.93 in the different suction rate of 100%, 200%, 300%, 400%, respectively in the end process. During the composting, the level of pH was increased from 6.83 to 8.67 and it gradually decreased to 7.56 in 100% and 200%(SR). At the same time, the pH values were reduced only up to 8.19 at 300%, and 8.08 at 400%(SR), showing that suction strengths of 100% and 200% were the better option for composting than those of 300% and 400%. The total Kjeldahl nitrogen (TKN) of initial composts mixtures was 2.3% and were changed in 3.3, 3.1, 2.5, and 2.3% at the end of the composting period from the 100%-400% (SR) variations respectively. These results also indicated that 100% and 200% (SR) were more affected by the dry mass loss as $CO_2$ and water evaporation. The initial value of C/N ratio was 25.17 and were significantly reduced to 11.88, 11.97, 14.31, and 14.72 at the end of the experiment, respectively from the 100%-400% (SR) variations. These results suggest that the suction rate (SR) of 100% and 200% relative to constant air supply would be the optimal conditions to produce high-quality compost.

A Study on Comics Outreach Programs for Contents marginalized Areas (콘텐츠 소외지역의 만화 아웃리치 프로그램 모델링 연구)

  • Lee, Seung-Jin
    • Cartoon and Animation Studies
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    • s.49
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    • pp.359-382
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    • 2017
  • Content is the complex of art and technology of trend, so it is important to experience different technologies for content education. Today, many non-profit organizations plan and operate numbers of programs for disabilities, low-income, and minority families to enhance the quality of life and the realization of social integration. These programs are limited to museums and galleries, not so pro-actively in progressing. Various contend education is necessary to the expansion of cultural exchange for the culturally alienated area. Naver is running an outreach program named . It is an experience-based outreach program where current cartoon / webtoon writers come directly to the school to inform students about the basic story of comics and comic techniques. However, the fact that the is not centered on the marginalized area but is centered on the Seoul Gyeonggi area, has the limitation that they can not benefit from a wide range of programs because they have a space limit of 'school', and, has a spatial limitation that the experience of the work is excluded. 'Outreach programs in marginalized areas' must be reorganized into a fluid dimension, not a fixed, single-system program. You should be able to experience and experience your work by directly using various professional equipment of comics based on your capacity and experience, local culture, religion, and society. These program participants will gain the effect of attractive and effective learning with empathy with their comic experience. Meanings of Comics content outreach program are following: First, the rich cultural archive can be used efficiently by providing various contents to existing outreach programs with the educational limitation of museums and galleries. Second, Comics contents can be enjoyed as a part of our life by understanding diversity and technology of contents. Third, because it is the program of expertise' participation, it can remodel, and restructure the severed experience in remote areas for the continuous growth and development, and furthermore, it can enhance the understanding of society.

Quality Assurance of Volumetric Modulated Arc Therapy Using the Dynalog Files (다이나로그 파일을 이용한 부피세기조절회전치료의 정도관리)

  • Kang, Dong-Jin;Jung, Jae-Yong;Shin, Young-Joo;Min, Jung-Whan;Kim, Yon-Lae;Yang, Hyung-jin
    • Journal of radiological science and technology
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    • v.39 no.4
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    • pp.577-585
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    • 2016
  • The purpose of this study is to evaluate the accuracy of beam delivery QA software using the MLC dynalog file, about the VMAT plan with AAPM TG-119 protocol. The Clinac iX with a built-in 120 MLC was used to acquire the MLC dynalog file be imported in MobiusFx(MFX). To establish VMAT plan, Oncentra RTP system was used target and organ structures were contoured in Im'RT phantom. For evaluation of dose distribution was evaluated by using gamma index, and the point dose was evaluated by using the CC13 ion chamber in Im'RT phantom. For the evaluation of point dose, the mean of relative error between measured and calculated value was $1.41{\pm}0.92%$(Target) and $0.89{\pm}0.86%$(OAR), the confidence limit were 3.21(96.79%, Target) and 2.58(97.42%, OAR). For the evaluation of dose distribution, in case of $Delta^{4PT}$, the average percentage of passing rate were $99.78{\pm}0.2%$(3%/3 mm), $96.86{\pm}1.76%$(2%/2 mm). In case of MFX, the average percentage of passing rate were $99.90{\pm}0.14%$(3%/3 mm), $97.98{\pm}1.97%$(2%/2 mm), the confidence limits(CL) were in case of $Delta^{4PT}$ 0.62(99.38%, 3%/3 mm), 6.6(93.4%, 2%/2 mm), in case of MFX, 0.38(99.62%, 3%/3 mm), 5.88(94.12%, 2%/2 mm). In this study, we performed VMAT QA method using dynamic MLC log file compare to binary diode array chamber. All analyzed results were satisfied with acceptance criteria based on TG-119 protocol.

Radiopharmceutical Factors in the Prepartion of $^{99m}Tc-HMPAO$ Images of the Brain (뇌스캔용 $^{99m}Tc-HM-PAO$의 방사성 동위원소표지에 영향을 미치는 인자에 대한 연구)

  • Yeom, Mi-Kyoung;Kim, Sang-Eun;Lee, Dong-Soo;Chung, June-Key;Lee, Myung-Chul;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.25 no.1
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    • pp.117-121
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    • 1991
  • Technetium-99m-hexamethylpropyleneamine oxime $(^{99m}Tc-HM-PAO)$ is a neutral-lipophilic chelate which is used for scanning cerebral blood flow. The labeling efficiencies of $^{99m}Tc-HM-PAO$ is known to be sensitive to the amount of pertechnetate added and the quality of the pertechnetate. Because of these factors, the manufacture recommends that HM-PAO kits be reconstituted with a maximum of 30 mCi pertechnetate which was eluted <4 hr earlier from a generator which had been eluted < 24 hr previously. So we measured the labelling efficiencies and the decomposition rate constant according to the amount of pertechnetate added, the volume of pertechnette added, and generator in-growth time. We used the 3-system chromatographic methods (paper & ITLC-SG chromatography) which analyzed the labelling efficiencies of the $^{99m}Tc-HM-PAO$. There was no significant difference in labelling efficiencies between variable pertechnetate acitvities added. ($39.9{\pm}4.9\;mCi:\;87.8{\pm}5.1\;(%)$, $60.8{\pm}5.0\;mCi:\;90.7{\pm}2.2\;(%)$, $79.0{\pm}6.0\;mCi:\;86.8{\pm}3.9\;(%)$, $106.6{\pm}11.6\;mCi:\;87.7{\pm}1.2\;(%)$, p>0.05) No significant difference in labelling efficiencies were found between pertechnetate of 4ml and 5ml. (4ml : $89.1{\pm}3.2(%)$, 5ml: $87.3{\pm}4.0(%)$, p>0.05). There was no difference between 1-6 and 10-48 hr of generator in-growth time. (1-6 hr: $87.8{\pm}4.0(%)$, 10-48 hr: $89.6{\pm}1.6(%)$, p>0.05) The mean value of decomposition rate constant was $0.196{\pm}0.097\;(hr^{-1})$, and there were no difference according to the amount of pertecnetate added and the volume of pertecnetate added, ($39.9{\pm}4.9\;mCi:\;0.208{\pm}0.059\;(hr^{-1})$, $60.8{\pm}5.0\;mCi:\;0.191{\pm}0.100\;(hr^{-1})$ $79.0{\pm}6.0\;mCi:\;0.192{\pm}0.118\;(hr^{-1})$, $106.6{\pm}11.6\;mCi:\;0.212{\pm}0.030\;(hr^{-1})$, p>0.05, 4 ml: $0.200{\pm}0.074\;(hr^{-1})$, Sml: $0.193{\pm}0.115\;(hr^{-1})$, p>0.05). In the case of using the first eluate, the labelling efficiency of $^{99m}Tc-HM-PAO$ W3S 82.1%. These data suggest that there were no significant alteration in labelling efficiency of $^{99m}Tc-HM-PAO$ according to the considerable range of pertechnetate activities and volume added, and generator in-growth time. Also, it was shown that one vial of HM-PAO kit supplied the $^{99m}Tc-HM-PAO$ which was used for 3-4 patients.

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A Study on Qian Yi(錢乙)'s Medical Though (전을(錢乙)의 의학사상(醫學思想)에 관(關)한 연구(硏究))

  • Oh, Jun Hwan;Kim, Ki Wook;Park, Hyun Kook
    • The Journal of Korean Medical History
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    • v.14 no.2
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    • pp.109-152
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    • 2001
  • Throughout this paper, I adjusted the study of 'Qian Yi'(錢乙)'s Medical Thought, and the following is the summary. 1. 'Qian Yi' wrote 'Xiao Er Yao Zheng Zhi Jue'("小兒藥證直訣", edited by 誾季忠), and there were 'Shang Han Lun Zhi Wei'("傷寒論指微"), 'Ying Ru Lun', however those are loss of the record. 2. Qian Yi's 'Zhi Jue'("直訣") was influenced by 'Lu Xin Jing', yet if we compare the quality of 'Sheng Li, Byeng Li, Bang Jae'(生理, 病理, 方劑), 'Lu Xin Jing' cannot be the foundation of 'Zhi Jue'. He took over 'Nei Jing, Shang Han Lun, Jin Gui Yao Lue, Shen Long Ben Cao Jing, Tai Ping Sheng Hui Fang'("內經", "傷寒論", "金?要略", "神膿本草經", "太平聖惠方") and put them together to the direct clinical experiences of pediatrics. 3. There is no reference regarding the difficulties of pediatric diagnosis and diseases in 'Huang Di Nei Jing'("黃帝內經") Before 'Bei Song'(北宋), regardless of the lack of data related to pediatric diseases, 'Qian Yi' established the pediatric system in 'Xiao Er Yao Zheng Zhi Jue' for the first time. 4. In his diagnosis of the pediatric diseases, he 'Si Zhen He Can'(四診合參), also considered in the eye exam seriously. In addition, he closely combined 'Wu Zang Bian Zheng'(五臟辨證), and diagnosis the pediatric diseases. 5. 'Wu Zang Bian Zheng', what Qian established method was based on 'Zheng Ti Guan'(整體觀) in 'Huang Di Nei Jing'. It was based on clinical experiences and established the perspectives of 'Tian Ren Xiang Ying'(天人相應). First of all, he pinpointed 'Zhu Zheng'(主證) clearly. Secondly, he pinpointed the relationships to symptoms and then, he distinguished a generic character of 'Xu, Shi, Han, Re'(虛, 實, 寒, 熱). Finally, he made an induction from genealogical pediatric physiology. 6. 'Qian Yi' took a serious view of 'Ban Zhen'(斑疹), the inadequate field in those days. At that time, he criticized on the habituation of the misuse of medication. He treated separately which 'Ji Jing'(急驚) as 'Liang Xie'(凉瀉) and 'Man Jing'(慢驚) as 'Wen Bu'(溫補). He proposed 'Cong Gan Zhu Feng, Xin Zhu Jing'(從肝主風, 心主驚) theory and formulated 'Jing Feng'(驚風) theory as well. 7. As an opponent of a tendency to misusage of medicine, 'Qian Yi' made out a prescription with pliant medicine. He emphasized on the treatment to 'Gong Bu Shang Zheng, Bu Bu Zhi Xie, Xiao Bu Jian Shi'(攻不傷正, 補不滯邪, 消補兼施) because he had so lucid demonstration to 'Xu Shi Han Re'(虛實寒熱) of the five viscera in the field of 'Bang Yak'(方藥). 8. There were no pediatrics schools at that time, however, the pediatrics was being made up gradually by 'Jin Yuan Si Da Jia'(金元四大家) who was influenced by 'Qian Yi'. He raised an objection to medical treatment using pliant medicine. 'Qian Yi' applied 'Qu Xia'(驅下) treatment using 'Han Liang'(寒凉) medicine. 'Han Liang Pai'(寒凉派) is greatly influenced by Qian. 'Chen Wen Zhong'(陳文中) had a great impact on 'Han Liang Pai' who used a 'Zao Shu Wen Bu'(燥熟溫補) medicine for treatment. Since 'Song Jin'(宋金), he had a tremendous influence on pediatrics treating patients in both 'Han Wen'(寒溫) ways. 9. 'Qian Yi' had an influence on his medical thoughts on future generations, especially to 'Wan Quan'(萬全) of 'Ming Dai', 'Wu Tang'(吳塘) of 'Qing Dai'(淸代) and 'Yun Shu Jie'(?樹珏) of 'Min Guo'(民國). 'Wan Quan' is an advocate of 'You Yu, Bu Zu Zhi Shuo'(有餘, 不足之說)of 'Xiao Er Wu Zang'(小兒五臟) that he revealed Qian's 'Wu Zang Bian Zheng'(五臟辨證). 'Wu Tang' disclosed Qian's 'Xiao Er Ti Zhi Shuo'(小兒體質說) and 'Xiao Er Ke'(小兒科)'s 'Yong Yao Lun'(用藥論), therefore, he uncovered pediatric physiological characteristics through the advocate of Qian's 'Zang Fu Rou Ruo, Ji Gu Nen Qie, Yi Xu Yi Shi, Yi Han Yi Re' (臟腑柔弱, 肌骨嫩怯, 易虛易實, 易寒易熱). 'Yun Shu Jie' developed intrinsic relationships among time, symptom and 'Tian Ren Xiang Ying Guan'(天人相應觀), What 'Qian Yi' stated about them. And also, he developed Qian's 'Di Huang Wan'(地黃丸), 'Xie Qing Wan'(瀉靑丸), 'Yi Huang San'(益黃散) clinical usages as well. 10. Regarding Qian's 'Wu Zang Xu Shi'(五臟虛實), it has an influence on 'Zhang Yuan Su'(張元素)'s 'Zang Fu Bing Ji Bian Zheng'(臟腑病機辨證). 'Di Huang Wan', 'Xie Qing Wan', 'Xie Xin Tang'(瀉心湯), 'Yi Huang San', 'Xie Huang San'(瀉黃散) are the standard prescription of 'Wu Zang Bu Xie'(五臟補瀉). It is under the influence of Qian's treatment. Besides, 'Qian Yi' took a serious view of 'Xiao Er'(小兒)'s 'Pi Wei'(脾胃). 'Qian Yi' had an impact on 'Li Dong Yuan'(李東垣) one of the member of 'Bu Tu Pai'(補土派). 'Di Huang Wan', which placed great importance on 'Bu Yi Shen Yin'(補益腎陰), had a great impact on 'Da Bu Yin Wan'(大補陰丸) and 'Jin Yuan Si Da Jia' as well. 11. In a theory of Qian's 'Wu Zang Bian Zheng', though it had been stated clearly in 'Wu Zang Bian Zheng', but he neglected in 'Liu Fu Bian Zheng'(六腑辨證). In prescription field, The problem with the medicine is that it is either toxic or mineral, therefore, we are not able to use those medicine in a clinical testing at the present time.

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Present Status and Future Prospect of Satellite Image Uses in Water Resources Area (수자원분야의 위성영상 활용 현황과 전망)

  • Kim, Seongjoon;Lee, Yonggwan
    • Korean Journal of Ecology and Environment
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    • v.51 no.1
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    • pp.105-123
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    • 2018
  • Currently, satellite images act as essential and important data in water resources, environment, and ecology as well as information of geographic information system. In this paper, we will investigate basic characteristics of satellite images, especially application examples in water resources. In recent years, researches on spatial and temporal characteristics of large-scale regions utilizing the advantages of satellite imagery have been actively conducted for fundamental hydrological components such as evapotranspiration, soil moisture and natural disasters such as drought, flood, and heavy snow. Furthermore, it is possible to analyze temporal and spatial characteristics such as vegetation characteristics, plant production, net primary production, turbidity of water bodies, chlorophyll concentration, and water quality by using various image information utilizing various sensor information of satellites. Korea is planning to launch a satellite for water resources and environment in the near future, so various researches are expected to be activated on this field.

A Study on the Realities of Custom-made Clothing Production in Middle-aged Women's Clothing Firms (중년여성복업체(中年女性服業體)의 맞춤복(服) 생산실태(生産實態) 연구(硏究))

  • Park, Yu-Jeong;Sohn, Hee-Soon
    • Journal of Fashion Business
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    • v.6 no.2
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    • pp.1-16
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    • 2002
  • The need for ready-to-wear clothing increases as the problem comes to arise from the fit of custommade clothing due to the characteristics of middle-aged women's somatotype. At this point of time, a study on the realities of production of custom-made clothing in middle-aged women's clothing business firms is of very greatly significance. Therefore, this study was intended to identify the problem and improvements through the survey research of production of custom-made clothing in middle-aged women's clothing business firms and further present the plan for development of custom-made clothing business. The questionnaire was framed based on the contents extracted from the preliminary questionnaire research for the pattern section chief of each business firm. Collected data were statistically processed using the SPSS 10.0 Windows program. As a result, the following findings were obtained: 1. The target age of the middle-aged women's clothing business firms ranged from more than 45 years to less than 50 years of age. Clothing business firms much made inroads into the ready-to-wear clothing market largely in the 1980s and the 1990s. Their active entry into the custom-made clothing market occurred in the 1970s and the 1980s. 2. In terms of the clothing production method of middle-aged women's clothing firms, some private boutique and designer brand clothing firms entered the clothing market with a focus on custom-made clothing in the beginning of its organization and introduced the production method of ready-to-wear clothing in accordance with changes in production methods and consumers' needs and wants. National brand clothing firms manufactured clothing with a focus on ready-to-wear clothing from the beginning of its organization, but at last they manufactured both partial custom-made and whole custom-made as the problem arose from ready-to-wear clothing. Seeing that their clothing production showed the ratio readyto-wear to custom-made clothing of 2.58:1. And it was found that the manufacture of ready-to-wear and custom-made clothing took into consideration the great difference in the pattern, size and design plan. The research of the clothing production process showed that whole custom-made and partial custommade were distinguished according to whether or not the sample was presented. 3. The ready-to-wear pattern of middle-aged women's clothing firms were used with a focus on the 'patternmaker-developed pattern' and company-developed pattern'. Most clothing businesses produced clothing in 4 to 5 basic sizes, which is found to be insufficient to complement the physical characteristics of middle-aged women with many specific somatotypes. In the pattern of custom-made clothing, the 'pattern of ready-to-wear were applied' or the 'customized pattern was developed'. Actual measurements were most used as the size of custom-made, and accordingly it is predicted that the level of satisfaction is higher with the fit of custom-made clothing than that of ready-to-wear. The selling place and the head office showed the similar percent as the place for measuring the size of custom-made clothing. Size measurers were mostly the shop master. And it was found that most clothing business firms had a problem when the measured size was applied to the pattern. Accordingly, it is necessary to provide education on size measurement for shop masters. 4. It was found that in the middle-aged women's clothing firms, the pattern correction of the length of sleeve, jacket and slacks occupied the highest percent. Accordingly, it is necessary to provide for the size system to complement the accurate somatotype characteristics of middle-aged women. 5. In custom-made clothing customer management, most firms engaged in customer somatotype management through size management. They provided customers with commodity information by informing them of the sales and event period and practiced human management for customers by maintaining the get-together and friendly relationship. 6. Middle-aged women's clothing businesses responded that it would be necessary to improve the fit of custom-made clothing and complement their pursuit for individuality as the plan to improve its quality. In consequence, it suggests that middle-aged women's clothing businesses should provide middle-aged women with the clothing of better-suited size and refined design. Middle-aged women's clothing businesses responded that it was the most urgent task to form the custom-made clothing manufacturing team as the plan to expand the custom-made clothing market, which is identified as their emphasis on the systematized production of custom-made clothing.

Evaluation of Image Quality for Various Electronic Portal Imaging Devices in Radiation Therapy (방사선치료의 다양한 EPID 영상 질평가)

  • Son, Soon-Yong;Choi, Kwan-Woo;Kim, Jung-Min;Jeong, Hoi-Woun;Kwon, Kyung-Tae;Cho, Jeong-Hee;Lee, Jea-Hee;Jung, Jae-Yong;Kim, Ki-Won;Lee, Young-Ah;Son, Jin-Hyun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • v.38 no.4
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    • pp.451-461
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    • 2015
  • In megavoltage (MV) radiotherapy, delivering the dose to the target volume is important while protecting the surrounding normal tissue. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using an edge block in megavoltage X-ray imaging (MVI). We used an edge block, which consists of tungsten with dimensions of 19 (thickness) ${\times}$ 10 (length) ${\times}$ 1 (width) $cm^3$ and measured the pre-sampling MTF at 6 MV energy. Various radiation therapy (RT) devices such as TrueBeam$^{TM}$ (Varian), BEAMVIEW$^{PLUS}$ (Siemens), iViewGT (Elekta) and Clinac$^{(R)}$iX (Varian) were used. As for MTF results, TrueBeam$^{TM}$(Varian) flattening filter free(FFF) showed the highest values of $0.46mm^{-1}$ and $1.40mm^{-1}$ for MTF 0.5 and 0.1. In NPS, iViewGT (Elekta) showed the lowest noise distribution. In DQE, iViewGT (Elekta) showed the best efficiency at a peak DQE and $1mm^{-1}DQE$ of 0.0026 and 0.00014, respectively. This study could be used not only for traditional QA imaging but also for quantitative MTF, NPS, and DQE measurement for development of an electronic portal imaging device (EPID).

Evaluation of Dosimetric Characteristics of Small Field in Cone Versus Square Fields Based on Linear Accelerators(LINAC) for Stereotactic Radiosugery(SRS) (선형가속기를 기반으로 한 뇌정위 방사선 수술 시 전용 콘과 정방형 소조사면의 선량 특성에 관한 고찰)

  • Yoon, Joon;Lee, Gui-Won;Park, Byung-Moon
    • Journal of radiological science and technology
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    • v.33 no.1
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    • pp.61-66
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    • 2010
  • In this paper we evaluated small field dose characteristics of exclusive cone fields versus square fields for stereotactic radiosugery (SRS) which is based on linear accelerators (LINAC). For this test, we used a small beam detector (stereotactic fields detector : SFD) with a 6 MV photon beam and a water phantom system (IBA, Germany). Percentage depth dose (PDD) was measured for different field sets (cones : ${\Phi}1\;cm$, ${\Phi}2\;cm$, ${\Phi}3\;cm$ ; square fields : $1{\times}1\;cm^2$, $2{\times}2\;cm^2$, $3{\times}3\;cm^2$) at a source skin distance (SSD) of 100 cm. We measured the point depths at 1.5 cm, 5 cm, 10 cm, 20 cm, and 30 cm. The output factors were measured under the same geometrical conditions of the PDD and normalized at the maximum dose depth. To analyze the penumbra, we measured the dose profile with 95 cm of SSD, 5 cm of depth for each field sizes (${\Phi}1\;cm$, ${\Phi}3\;cm$, $1{\times}1\;cm^2$, and $3{\times}3\;cm^2$) using SFD. We obtained the values for every 1 mm interval in the physical field (90%) and 0.5 mm interval in the penumbra region (20 to 80%). The PDD variation of exclusive cones and square fields were 4.3 to 7.9% lesser than the standard field size ($10{\times}10\;cm^2$. The variation of PDD was reduced while the field size was increased. To compare the beam quality, we analyzed the $PDD_{20,10}$ and the results showed under the 1% of variations for all experiments except for ${\Phi}1\;cm$ cone and $1{\times}1\;cm^2$ fields. Output factors of exclusive cone were increased 3.1~4.6% than the square fields, and the penumbra region of exclusive cone was reduced 20% as compared to the square fields. As the previous researches report, it is very important for SRS and SFD that precise dosimetry in small beam fields. In this paper, we showed the effectiveness of exclusive cone, compared to square field. And we will study on the various detector characteristics for small beam fields.