• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.69-78
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• 2014

The paper recycling becomes more important technology in terms of the reduction of the municipal waste and of saving natural resource such as wood. However the more utilization of recycled fiber would result in the higher contaminants in the papermaking processes and in the deterioration of the paper quality. The oil marks in the paper products becomes one of the major defects of paper products originated from paper recycling. The coagulation of various stickies in recycled fiber stock led to the oil marks. In this work, we applied functional polymer additives such as the dispersing agents, the fixing agents and the hydrophobic talc powder for the control of those stickies in order to remove the oil marks. The addition of the talc powder showed the great reduction in the oil marks of the packaging paper products. The hydrophobic surface of the talc particles collected the individual sticky materials and prevented their aggregation in the recycled fiber stock, which resulted in the great reduction of the oil marks on the paper products.

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1093-1130
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• 2009

The purpose of this study is to examine obstacles to progress for 20th century Korean mathematics. In 1945, shortly after Korea was liberated from Japan, there were no Korean mathematics Ph.D. holders, less than ten bachelor degree holders, and only one person with a master's degree in mathematics. We investigate the reasons for this. Korea has to overcome such an unforgiving condition and rebuild quality education programs in higher mathematics over the last several decades. These debilitating circumstances in higher mathematics were considerable obstacles in developing a higher level of mathematical research for the mainstream of 20th century world mathematics. We study policy and curriculums of Korean school mathematics in the late 19th and early 20th century, with some educational and socio-political background.

• Journal of Legislation Research
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• no.41
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• pp.125-170
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• 2011

In Korea, the evolution of welfare for people with disabilities can be divided largely four stages. The first phase is before 1981, the second is from 1981 to 1988, the third is from 1989 to 2006 and the fourth phase is from 2007 to now. In the first phase people with disabilities were considered as ones of charity. In the second period the welfare ideal for people with disabilities was appeared. In the third, the framework of welfare system for people with disabilities was formed and welfare services began to be expanded. The fourth phase has been the time to secure human right and social services for people with disabilities. In Korea, for people with disabilities, 2007 was the year of historical turning point. "The Act of Prohibition on Disability Discrimination and Remedy for Right"was built that year and became effective the next year. Also "The Special Education Act for People with disabilities" was enacted newly. "The Disabled Welfare Act" was amended for the change of welfare paradigm. The change is introduction of Independent Living. After 2007 Korean legal systems for people with disabilities have been improved largely.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.2 s.25
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• pp.139-144
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• 2006

Recently, ships' average navigation speed become faster than before because of the increasing of high-speeds vessel including container ships and passenger-ferries. So, it is considered that the speed limit in the navigation channel in Korea isn't proper for vessel management in these days. Also, there is rare paper studies about the speed limit quantitatively and numerically, especially the speed limit is discussing continuously, as abrogation of Incheon Port's speed limit and alleviation of Gwang-yang Port's speed limit according to the requests by the navigating mariners. Consequently this paper deals with the effectiveness of speed limits using the Environmental Stress Model, after replay of the navigation traffic flow in the straight waterway using marine traffic flow simulation technique.

• Journal of the Korean Solar Energy Society
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• v.28 no.4
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• pp.10-16
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• 2008

The fire resistance of thermal insulation and interior finishing materials is recently much emphasized after the fire accident at the Icheon Cold Store in January 2008. Three kinds of thermal insulation are used in buildings. They are Organic, Non-organic and cellulosic insulation. Organic insulation such as polystyrene foam board and urethane foam has high thermal resistance but it has no fire resistance. While non-organic insulation such as rockwool and glassfiber has high fire resistance, it has lower thermal resistance than organic insulation. Cellulose insulation is primarily manufactured from recycled newsprint or cardboard using shredders and fiberizers. Despite of its environmental friendliness and high thermal resistivity, its domestic use has not much increased because of the prejudice that paper can easily burn. However, the cellulose insulation as a product is about 80 wt.% cellulosic fiber and 20 wt.% chemicals, most of which are fire retardants such as boric acid and ammonium sulfate. It is required to secure its fire safety for more consumption as a building insulation in Korea. Therefore, this study investigates the fire resistance of Korean cellulose insulation according to the rate of fire retardant and finally presents the optimum rate of fire retardant in cellulose as building insulation. The fire safety test was conducted according to the ASTM C 1485-00. The test results indicate that above 18 wt% of fire retardant is necessary to secure the fire safety of cellulose insulation.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.287-293
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• 2021

Recently, public certificates issued by nationally-recognized certification bodies have been abolished, and internet companies have issued their own common certificates as certification authority. The Electronic Signature Act was amended in a way to assign responsibility to Internet companies. As the use of a joint certificate issued by Internet companies as a certification authority is allowed, it is expected that the fraud damage caused by the theft of public key certificates will increase. We propose an authentication model that can be used in a security gateway that combines PKI with a blockchain with integrity and security. and to evaluate its practicality, we evaluated the security of the authentication model using Sugeno's hierarchical fuzzy integral, an evaluation method that excludes human subjectivity and importance degree using Delphi method by expert group. The blockchain-based joint certificate is expected to be used as a base technology for services that prevent reckless issuance and misuse of public certificates, and secure security and convenience.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.339-347
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• 2021

The purpose was to analyze the trend of sport pedagogy in secondary teacher certification examination based on the secondary teacher qualification criterion in Korea Institute for Curriculum and Evaluation since abolition of multiple-choice questions from 2014 to 2020. The result showed the questions for sport pedagogy were 48 question since 2014, and found 83 sub-questions. The implications are as follows. First, the frequency of sub-questions in sport pedagogy has increased, causing an integrated question. Second, the serious unbalanced issue of questions for examination was presented. Third, dependence on specific domains was excessively high. Fourth, the confusion caused by the overlapped domains with the content knowledge of physical education subject was intensified. Therefore, evaluation factors based on 2016 KICE classification table should be clear and field application questions should be developed.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.229-239
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• 2021

For this study, we have extensively analyzed the presentation data of the government's financial-related departments and the data of each financial institution and electronic financial institution.. As a result, In Korea's electronic financial environment, real changes such as first) expansion of non-face-to-face finance, second) teleworking in the financial sector, third) abolition of accredited certification, fourth) advanced voice phishing, fifth) openness of the financial industry and diversification of forms, sixth) the'walletless society'. In addition to the above, however, global changes triggered by the Fourth Industrial Revolution spread to the financial security sector, making it difficult to respond to problems such as artificial intelligence/ deep learning/ user analysis/ deepfake technology. As the proportion of electronic finance is increasing socially, it should be studied in the fields of electronic finance and its environment, and crime and criminal investigation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.304-310
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• 2018

The aim of the research is to provide possibility of quality controlling by rheological properties for lightweight foamed concrete. The lightweight foamed concrete achieves its low density by containing air bubbles (foam) produced during the mixing process. Therefore, containing foamed volume during setting period is critical for the securing the performance as an insulating material. In this research, regarding foam collapse during the setting period, rheolgocial properties of fresh state lightweight foamed concrete were assessed to get its relationship with volume stability, or foam stability. For the experiment regarding foaming factors including mixing time, mix design of contents for materials, rheological properties of fresh state lightweight foamed concrete were tested with its density and settling depth. Based on the settling depth with various factors, relationship with rheological properties was analyzed, and especially, close relationship of plastic viscosity and settling depth was found. Therefore, from the results of this research, it is considered to contribute on suggesting a new approach of quality controlling for lightweight foamed concrete using rheological test method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.1-14
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• 2019

In order to minimize problems related to the performance and safety of automobiles, the "Age Limit for Vehicles System" which restricts the age of buses, taxis, and trucks, was implemented in 1973. This contributed to the reduction of accidents and increase of user's service satisfaction. However, the restriction system for trucks was abolished in August 1997 as it was deemed restrictive to economic growth. It is found that one of main causes of traffic accidents such as Changwon Tunnel accident occurred in recent years, is the aging of trucks. Thus, There is a growing need for the management of the age of trucks. In this study, the time when cargo vehicles need to be managed is suggested, by analyzing the safety of cargo vehicles using vehicles inspection data.