• Computers and Concrete
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• v.21 no.3
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• pp.279-289
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• 2018

Hydration heat and thermal induced cracking have always been a fatal problem for massive concrete structures. In order to study a massive reinforced concrete wall of a storage tank for liquefied natural gas (LNG) during its construction, two mock-ups of $0.8m{\times}0.8m{\times}0.8m$ without and with metal corrugated pipes were designed based on the actual wall construction plan. Temperature distribution and strain development of both mock-ups were measured and compared inside and on the surface of them. Meanwhile, time-dependent thermal and mechanical properties of the concrete were tested standardly and introduced into the finite-element (FE) software with a proposed hydration degree model. According to the comparison results, the FE simulation of temperature field agreed well with the measured data. Besides, the maximum temperature rise was slightly higher and the shrinkage was generally larger in the mock-up without pipes, indicating that corrugated pipes could reduce concrete temperature and decrease shrinkage of surrounding concrete. In addition, the cooling rate decreased approximately linearly with the reduction of heat transfer coefficient h, implying that a target cooling curve can be achieved by calculating a desired coefficient h. Moreover, the maximum cooling rate did not necessarily decrease with the extension of demoulding time. It is better to remove the formwork at least after 116 hours after concrete casting, which promises lower risk of thermal cracking of early-age concrete.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.187-195
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• 2020

The purpose of study is to find ways to improve online research work in the near future environment. Study methods and results are as follows. First, the basis of research was secured through theoretical consideration. Second, three types were derived by collecting examples. There are reward, execution and visualization. Third, comprehensive matrix and directions were derived through case analysis. According to the study, the most frequently used phase of AI technology were analysis, visualization, execution, casting, design, and matching, The direction of use of AI can be largely divided into work efficiency, human thought assistance, and changes in research methods. But the plan phase is generally scarce. Overall, the lack of in function is provided, including AI technology. At a time when research plans are becoming more important as users and products diversify.

• Spatial Information Research
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• v.17 no.1
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• pp.145-157
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• 2009

Rapidly evolving field of GIS and the social demand for university education to address the gap in the training of human resources, and future-oriented, engineering accreditation system based on the introduction of measures in the field of GIS is the need. In this thesis, the domestic and international undergraduate curriculum including University of Seoul's was analysed. A GIS curriculum of the domestic and abroad department course was analyzed. The present status of the domestic engineering accreditation and problems were analyzed and a desirable casting plan was shown through the abroad GIS related accreditation case analysis to analyze the validity of the engineering accreditation introduction of the GIS field. A standardized GIS curriculum was shown through the analysis of the core curriculum and the body of knowledge of the GIS field shown at the advanced of foreign countries all together. The industry-academia cooperation forum which made the Surveying and GIS related society the center by a political alternative, the construction of the caucus and the argument to execute this effectively are needed.

• Journal of architectural history
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• v.23 no.6
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• pp.47-54
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• 2014

Hwangrong Temple was the center of the Buddhist culture of Silla dynasty. It was built in the 14th year of King Jinheung in Silla dynasty, and completely burnt out when the Mongol Army invaded the Korean peninsula during the reign of King Gojong of Koryeo dynasty. 8-year excavation of the site from 1976 as part of the Gyeongju Tourism Comprehensive Plan revealed many things about the Hwangrongsaji. Recently, a book introduced 'Geumdongnanganpyeon' among relics found in the site, but omitted in the Excavation Report published at that time. Though 'Palgak Geumdongnanganpyeon' has numerical signs 六, 七(six, seven), there was no clear explanation of the signs. Thus, this paper examines it. We can guess, through the remaining iron fragment, that the side of Geumdongnanganpyeon is octagonal, and the width of the side S13 fragment belongs to is about 400mm. The overall form of the face is similar to the Geumdong Palgaktop stored in the Museum of Dongguk University, but, in detail, it is similar to the Zhuanlunzang Pavilion of Longxing Temple and the Sakyamuni Pagoda of Fogong Temple in China. And, numerical signs can be understand to designate the numbers of story and face. The reason why the number might indicate the number of story is that fragments which are presumed to be used for the same purpose contain different measurement values, and the basis of the concept of face can be found in efficiency of manufacturing and manufacturing techniques of artifacts of the time. The two aspects mentioned above cannot be confirmed because of not sufficient relics and related researches. But, the overall form may have been multi-story tower of at least two stories. If more studies in various fields are done in the future, it is expected that the original form will be recovered more accurately.

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.49-64
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• 2007

This research collected the curriculum for Dental Technology from a total of 20 schools -3-year colleges and 4-year colleges- all in Korea. And we analyzed the average credits of subjects from students. As a result of this analysis, we get the conclusion below: 1. In a distribution which students answered about each subjects; Seminar, Dental morphology I II, Dental morphology practice I II, and Dental devices & instruments don't have many credits and mostly have a converged tendency in high points, according to the arithmetic mean of the major basis subjects. 2. In an analysis of the correlation which is based on the distinction of sex: Complete denture prosthodontics I II III, Dental orthodontics I II, Dental orthodontics practice I II, and Dental orthodontics & practice III have a meaningful difference. ($\rho$< 0.05 ) 3. In an analysis of the correlation which is based on an age The major basis subjects -Introduction to dental technology, Dental esthetic, and Dental casting procedure-, and the major application subjects -Crown and bridge prosthodontics practice, Complete denture prosthodontics, Dental orthodontics, Dental orthodontics practice, and Operative dentistry laboratory technology- have meaningful difference. ($\rho$< 0.05 ) 4. In a correlation coefficient between subjects; The correlation coefficient of the major application subjects is higher than the major basis subjects. According to the student - t, we found that the level of significance is $\rho$< 0.001, which is meaningful. We feel the lack of a limitation which we didn't survey all students who are major in Department of Dental Technology. And we also feel that we'd better to consider not only students who being in college but also graduated students.

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.340-346
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• 2004

The plan for obtaining a good combination of strength and castability appeared feasible and the following observations were made. 1. In Al-12Mg-6.6Zn-xSi alloys, more primary $Mg_2Si$ phase formed with reduced $Al_3Mg_2$ phase, as Si content is necessary for an effective solution heat treatment because the solidus temperature is very low silicon contents. 2. A high tensile strength could be obtained in the heat-treated Al-12Mg-5.5Zn-5Si alloy attributed in the heat-treated Al-12Mg-5.5Zn-5Si alloy attributes to fine $MgZn_2$ particles that precipitated uniformly in the matrix. 3. Al-12Mg-5.5Zn-Si alloys showed excellent casting capabilities such as hot cracking resistance and fluidity compared to the reference commercial alloys. 4. The wear resistance of Al-12Mg-5.5Zn-5Si alloy was superior to that of A7075 alloy, and even higher resistance is expected if the morphology and size of primary $Mg_2Si$ phase is carefully controlled.

• Journal of National Security and Military Science
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• s.8
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• pp.169-238
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• 2010

The year 2010 is the 60th anniversary commemorating the Korean War. China intervened in the Korean War with the logics such as "To Resist the U.S.'s Aggression and Aid North Korea," "Save Endangered Home & defend Nation," and "If the Lips Are Gone, the Teeth Will Be Exposed to the Cold or If One of Them Falls, the Other is in Danger." However, China had a deep and long connection with North Korea through 1st Chinese Civil War, war against Japan imperialism, and 2nd Chinese Civil War. China has consulted with Kim Il-sung on his invasion of South Korea at the initial stage of development and played a casting vote role in the execution of the invasion plan. During the Korean War, the PLA supported the North Korea's regime by its action, and made the Korea Peninsula divide into two semi-permanently. Even after the war, China continues to maintain relations with North Korea by helping North Korea build the Kim Il-sung's Kingdom. Currently, whenever any issue related to North Korea rises in the international society, China definitely gets involved in those issues and exercises its power. Conditionally 'either armed aggression or, and wartime' in North Korea, China would follow the "Clause of Military Auto Intervention." In addition, China is very likely to establish refugee camps for North Koreans in the Northeastern-Three-Province and to provide rear bases or guerrilla camps for pro-Chinese sects. Furthermore, voluntarily playing a role as spokesman of North Korean Regime in the international society, China will exercise enormous influence on the reunification of the Korean Peninsula.

• Journal of Korea Foundry Society
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• v.42 no.1
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• pp.3-11
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• 2022

In this study, the parameters on the shrinkage defect of HR3C alloy was secured through computer simulation research, and the ingot mold with greater than 85% of sound area was designed and manufactured. Moreover, the optimized coagulation was proposed at design stage through computer simulation and test was performed upon ingot manufactured. After the test, the defect pattern was analyzed through cutting and non-destructive inspection to verify the parameter and ingot mold design. Based on the verification results, shrinkage defect parameters such as Niyama, Feed Efficiency, and Hot Tear Intensity of HR3C Alloys were obtained. In addition, through the secured parameters, a plan for designing ingot mold with a Non-defect area of 85% or more was secured.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.75-81
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• 2019

Purpose: Helmet type bolus for 3D printer is being manufactured because of the disadvantages of Bolus materials when photon beam is used for the treatment of scalp malignancy. However, PLA, which is a used material, has a higher density than a tissue equivalent material and inconveniences occur when the patient wears PLA. In this study, we try to treat malignant scalp tumors by using M3 wax helmet with 3D printer. Methods and materials: For the modeling of the helmet type M3 wax, the head phantom was photographed by CT, which was acquired with a DICOM file. The part for helmet on the scalp was made with Helmet contour. The M3 Wax helmet was made by dissolving paraffin wax, mixing magnesium oxide and calcium carbonate, solidifying it in a PLA 3D helmet, and then eliminated PLA 3D Helmet of the surface. The treatment plan was based on Intensity-Modulated Radiation Therapy (IMRT) of 10 Portals, and the therapeutic dose was 200 cGy, using Analytical Anisotropic Algorithm (AAA) of Eclipse. Then, the dose was verified by using EBT3 film and Mosfet (Metal Oxide Semiconductor Field Effect Transistor: USA), and the IMRT plan was measured 3 times in 3 parts by reproducing the phantom of the head human model under the same condition with the CT simulation room. Results: The Hounsfield unit (HU) of the bolus measured by CT was $52{\pm}37.1$. The dose of TPS was 186.6 cGy, 193.2 cGy and 190.6 cGy at the M3 Wax bolus measurement points of A, B and C, and the dose measured three times at Mostet was $179.66{\pm}2.62cGy$, $184.33{\pm}1.24cGy$ and $195.33{\pm}1.69cGy$. And the error rates were -3.71 %, -4.59 %, and 2.48 %. The dose measured with EBT3 film was $182.00{\pm}1.63cGy$, $193.66{\pm}2.05cGy$ and $196{\pm}2.16cGy$. The error rates were -2.46 %, 0.23 % and 2.83 %. Conclusions: The thickness of the M3 wax bolus was 2 cm, which could help the treatment plan to be established by easily lowering the dose of the brain part. The maximum error rate of the scalp surface dose was measured within 5 % and generally within 3 %, even in the A, B, C measurements of dosimeters of EBT3 film and Mosfet in the treatment dose verification. The making period of M3 wax bolus is shorter, cheaper than that of 3D printer, can be reused and is very useful for the treatment of scalp malignancies as human tissue equivalent material. Therefore, we think that the use of casting type M3 wax bolus, which will complement the making period and cost of high capacity Bolus and Compensator in 3D printer, will increase later.

• Journal of Korea Technology Innovation Society
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• v.19 no.1
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• pp.191-229
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• 2016

As Korean national R&D projects have steadily grown in size, the needs of enhancing the efficiency and effectiveness of the national R&D budge spending has been also discussed. Therefore, many efforts have been made to establish performance assessment system to improve the efficiency and effectiveness of the national R&D project. One example of such efforts is the stipulation of connecting the results of performance evaluation ranking of the national R&D projects with the budge allocation of for the coming fiscal year. Unlike the stipulated article in the law/regulation that 'more budge shall be allocated to a project rated over excellent grade and vice versa', however, precedent studies have been casting mixed opinions over to the effectiveness of the connection between assessment results and budge allocation. In this respect, the present study attempted to empirically examine if the laws and institutions related to the results of performance evaluation ranking of the national R&D projects with the budge allocation work properly, using panel regression analysis and quantitative data. In addition, this study investigated into the deterrent factors to the connectivity between the performance results of the national R&D projects and budge allocation and sought for a way to improve the system of performance assessment and enhance the reliability of the results by minimizing the hindrance factors.