• Investigative Magnetic Resonance Imaging
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• v.23 no.3
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• pp.179-201
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• 2019

Portable low-cost magnetic resonance imaging (MRI) systems have the potential to enable "point-of-care" and timely MRI diagnosis, and to make this imaging modality available to routine scans and to people in underdeveloped countries and areas. With simplicity, no maintenance, no power consumption, and low cost, permanent magnets/magnet arrays/magnet assemblies are attractive to be used as a source of static magnetic field to realize the portability and to lower the cost for an MRI scanner. However, when taking the canonical Fourier imaging approach and using linear gradient fields, homogeneous fields are required in a scanner, resulting in the facts that either a bulky magnet/magnet array is needed, or the imaging volume is too small to image an organ if the magnet/magnet array is scaled down to a portable size. Recently, with the progress on image reconstruction based on non-linear gradient field, static field patterns without spatial linearity can be used as spatial encoding magnetic fields (SEMs) to encode MRI signals for imaging. As a result, the requirements for the homogeneity of the static field can be relaxed, which allows permanent magnets/magnet arrays with reduced sizes, reduced weight to image a bigger volume covering organs such as a head. It offers opportunities of constructing a truly portable low-cost MRI scanner. For this exciting potential application, permanent magnets/magnet arrays have attracted increased attention recently. A magnet/magnet array is strongly associated with the imaging volume of an MRI scanner, image reconstruction methods, and RF excitation and RF coils, etc. through field patterns and field homogeneity. This paper offers a review of permanent magnets and magnet arrays of different kinds, especially those that can be used for spatial encoding towards the development of a portable and low-cost MRI system. It is aimed to familiarize the readers with relevant knowledge, literature, and the latest updates of the development on permanent magnets and magnet arrays for MRI. Perspectives on and challenges of using a permanent magnet/magnet array to supply a patterned static magnetic field, which does not have spatial linearity nor high field homogeneity, for image reconstruction in a portable setup are discussed.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.222-239
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• 2019

This paper studied Joseon royal incense, Buyonghyang, focusing on the case of Sunjo Sunwonwanghoo Garyedogam Uigwe. Incense was introduced to Korea in the period of the Three States with Buddhist cultures. Buyonghyang is an incense that represented the royal family and was used in various rituals. Civilians also burned this incense in front of a bride's palanquin at a wedding ceremony. Buyonghyang had various uses-ceremonial uses, as a fragrance, to mothproof, and medical uses. Buyonghyang is a combined incense with ten different ingredients. This study tracked the supply and demand of the incense ingredients through Takjijunjeol, Sejong Shilok Jiriji, and The Annals of the Joseon Dynasty. This paper identified properties of the ingredients and studied recipes using ancient medical books-Jejungshinpyeon, Donguibogam, etc. Then the cooperation and treatment of incense by craftsman were examined using the records of The Annals of the Joseon Dynasty, and Seungjeongwon Ilgi. The significance of Buyonghyang during the Joseon dynasty was studied by examining its use at a royal wedding ceremony. This study considered Sunjo's wedding ceremony based on Sunjo Sunwonwanghoo Garyedogam Uigwe which is highly regarded as a well-organized system compared to other Uigwe. Buronghyang was burned during all of the ceremonies which took place in the palace. Conversely, it is considered that Buyonghyang was burned only during the Bisuchekui ceremony (investiture), which took place in the bride's place, according to the record of the mobilization of court ladies for various incense burners for the Bisuchekui ceremony. Since the incense was able to be used only after Bisuchekui, it is considered that only the royal family could use the incense, and it was a symbolic incense of the Joseon Royal Family.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.5
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• pp.475-481
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• 2019

A splint is one of assisting devices for the disabled with hemiplegia or contracture and is manually made by an experienced expert. Heated thermoplastic materials are continuously fitted to the affected part. This traditional method has a possible risk of low-temperature burn, quality variance of the splint due to the proficiency of maker. etc. While various approaches has been made using 3D printing technology in order to redeem those disadvantages, they still carry high cost issues with 3D scanners or accuracy issues with manual measurement. This research begins with symmetrical characteristics of human body and focuses on the preliminary study for the possibility of splint manufacturing with 3D printing technology based on geometric characteristics of unaffected arm. 3D right and left forearm models of healthy male adults were created by photogrammetry software and a series of digital images in order to measure the circumference and cross-sectional area of the forearm models at every 20mm from the elbow. The circumference and cross-sectional area showed tolerable levels of differences between both sides within subjects; The circumference and cross-sectional area showed very strong correlations between both sides within subjects. From these findings, the possibility of splint manufacturing with 3D printing technology could be confirmed based on the geometric characteristics of unaffected side.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.325-355
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• 2007

A national funeral was a ceremony for king symbolizing a country in Joseon. The Gukjangdogam had three practical affairs: ibang and ibang, sambag. Each practial affairs was ready for various implement and finished a national funeral very well. So various important. The Daeyeo and the Gyeonyeo which carried directly the dead from a palace to a burial in the national funeral was a chief implements to handle with careful. All people had to carry heartily him as a Daehaewang which means a previous king. But three practical affairs belonging to the Gukjangdogam made various implements directly or indirectly related in a Daehaengwang and symbolized has authority. They were related in succeeding to the throne. The departure of a funeral in Joseon was a space and a time to appear his authority. The Gukjangdogam progressed it like going in and out the palace in the life. We knew it was ready for the departure of a funeral equalizing to the life and the death. The Gukjangdogam made the best of various implements using in going in and out the palace in the departure. We saw the Confucian view about living and dying through the implements used in the departure. The Gukjangdogam assembled many technicians around the country. They had to make various implements as high-level technicians at certain hour under the supervision of officials. The Gukjangdogam payed and compensated for their labors. There is an indissoluble connection between them. The technicians belonging to three practical affairs were ready for the implements for a national funeral: newly-made and repair, existed-implements use etc. So a national funeral can be called 'the feast of techniques' as well as complexity of techniques' in the Joseon.

• Convergence Security Journal
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• v.17 no.5
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• pp.111-119
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• 2017

As of March 2017, fake news is largely focused on political issues. Outside the country, main issues of the fake news have been a hot topic in the US presidential election in 2016 and emerged as a new political and social problem in countries like Germany and France. In Korea, issues of the fake news are also linked with political issues such as presidential impeachment and prosecution, impeachment quota, early election, etc. This phenomenon has recently led to the production and spread of fake news related to safety and security issues as well as political issues in connection with various methods of generating articles and sharing information. As a result, there is a high possibility that the information will be transformed into information that can cause considerable confusion to the public. Therefore, the recognition of such problems means that it is important at this point to consider the related situation analysis and effective countermeasures. To do this, we tried to make accurate and meaningful analysis for the diagnosis, analysis, forecasting and management of issues utilizing Big Data. As a result, it is found that the fake news is continuously generated in relation to the safety and security issue as well as the political issue in the South Korea, and differs from the general form occurring outside the country.

• Convergence Security Journal
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• v.18 no.1
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• pp.19-31
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• 2018

As the ICT technologies advance, the unprecedently large amount of digital data is created, transferred, stored, and utilized in every industry. With the data scale extension and the applying technologies advancement, the new services emerging from the use of large scale data make our living more convenient and useful. But the cybercrimes such as data forgery and/or change of data generation time are also increasing. For the data security against the cybercrimes, the technology for data integrity and the time verification are necessary. Today, public key based signature technology is the most commonly used. But a lot of costly system resources and the additional infra to manage the certificates and keys for using it make it impractical to use in the large-scale data environment. In this research, a new and far less system resources consuming signature technology for large scale data, based on the Hash Function and Merkle tree, is introduced. An improved method for processing the distributed hash trees is also suggested to mitigate the disruptions by server failures. The prototype system was implemented, and its performance was evaluated. The results show that the technology can be effectively used in a variety of areas like cloud computing, IoT, big data, fin-tech, etc., which produce a large-scale data.

• The Journal of Society for e-Business Studies
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• v.24 no.1
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• pp.121-137
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• 2019

De-identification is a method by which the remaining information can not be referred to a specific individual by removing the personal information from the data set. As a result, de-identification can lower the exposure risk of personal information that may occur in the process of collecting, processing, storing and distributing information. Although there have been many studies in de-identification algorithms, protection models, and etc., most of them are limited to structured data, and there are relatively few considerations on de-identification of unstructured data. Especially, in the medical field where the unstructured text is frequently used, many people simply remove all personally identifiable information in order to lower the exposure risk of personal information, while admitting the fact that the data utility is lowered accordingly. This study proposes a new method to perform de-identification by applying the k-anonymity protection model targeting unstructured text in the medical field in which de-identification is mandatory because privacy protection issues are more critical in comparison to other fields. Also, the goal of this study is to propose a new utility metric so that people can comprehend de-identified data set utility intuitively. Therefore, if the result of this research is applied to various industrial fields where unstructured text is used, we expect that we can increase the utility of the unstructured text which contains personal information.

• Convergence Security Journal
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• v.17 no.5
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• pp.41-47
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• 2017

The Marine Environment Observation Information System supplies oceanographic information elements such as water temperature, chlorophyll, float, etc. based on satellite images to consumers. The data produced by the Korean marine environmental observatories are located in the coastal areas of Korea. But if the range is too far from a particular area of interest, due to distance or spatial constraints, the accuracy and up-to-dateness of the data can not be relied upon. Therefore, it is necessary to perform fusion and complex operation to solve the difference between the field observation and the marine satellite image. In this study, we develop a system that can process marine environmental information in the user's area of interest in the form of layered character (numeric) information considering the readability and light weight rather than the satellite image. In order to intuitively understand satellite image information, we characterize (quantify) the marine environmental information of the area of interest and we process the satellite image band values into layered characters to minimize the absolute amount of transmitted / received data. Also we study modular location-based interest information service method to be able to flexibly extend and connect interested items that diversify various observation fields as well as application technology to serve this.

• Publications of The Korean Astronomical Society
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• v.34 no.2
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• pp.17-28
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• 2019

The Korean Astronomical Society (KAS) Education & Public Outreach Committee has provided education services for children and school teachers in Cambodia over the past three years from 2016 to 2018. In the first year, 2016, one KAS member visited Pusat to teach astronomy to about 50 children, and in the following two years of 2017 and 2018, three and six KAS members, respectively, executed education workshops for ~ 20 (per each year) local school teachers in Sisophon. It turned out that it is desirable to include both teaching of astronomical knowledge and making experiments and observations in the education in order for the program to be more effective. Language barrier was the main obstacle in conveying concepts and knowledge, and having a good interpreter was very important. It happens that some languages, such as the Khmer of Cambodia, do not have astronomical terminologies, so that lecturers and even the education participants together are needed to communicate and create appropriate words. Handout hard-copies of the education materials (presentation files, lecture/experiment summaries, terminologies, etc.) are extremely helpful for the participants. Actual performing of assembling and using astronomical telescopes for night sky observations has been lifetime experience for some of the participants, which might promote zeal for knowledge and education. It is hoped that these education services for developing countries like Cambodia can be regularly continued in the future, and further extended to other countries such as Laos and Myanmar.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.359-385
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• 2005

Red ocher, red lead or cinnabar has been as red colorant for ages. Cinnabar of the red pigments has been highly regarded as a valuable ingredient because it represent a symbol of exorcising and a haute image. It was used as a pigment of painting and mural painting, bowl, clothes, rock writing, gravestone, etc. It is powder which dissolves in perilla oil or glue before using. Because it is high-priced, the use of cinnabar may be limited to the privileged class. Therefore, red ocher or red lead was used instead of cinnabar. "Gongsagyunmunrok" demonstrated that government official's gravestonea has been painted red by two colorants in the period of the Goryeo dynasty. However, cinnabar may be used to paint gravestones for the first time in the period of the Three States because it has been transmitted since the times. This study discuss the results obtained from an analysis of the pigments used on the red pigments of the Stone Monuments. The results can be briefly summarized as below; First, the microcrystalline structures seen on the surface section of analyzed pigments, samples of which were taken from various parts of red pigments show that different sizes and shapes of pigment particle. Second, a result of the analysis on the composition and structure of the pigments shows that the main components in their composition are : Red pigments - Red lead($Pb_3O_4$), Cinnabar(HgS) and Hematite($Fe_2O_3$) White pigments - Calcite($CaCO_3$) Especially, we knew that red Stone Monuments were found to be natural mineral pigments, which were used as a singular or a mixture.