• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.935-942
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• 2021

Involuntary movement of internal organs by respiration is a factor that greatly affects the results of radiotherapy and diagnosis. In this study, a moving phantom was fabricated to simulate the movement of an organ or a tumor according to respiration, and ¹⁸F-FDG PET/CT scan images were acquired under various respiratory simulating conditions to analyze the movement range of the tumor movement by respiration, the level of artifacts according to the size of the tumor and the maximum standardized uptake value (SUVmax). Based on Windows CE 6.0 as the operating system, using electric actuator, electric actuator positioning driver, and programmable logic controller (PLC), the position and speed control module was operated normally at a moving distance of 0-5 cm and 10, 15, and 20 reciprocations. For sphere diameters of 10, 13, 17, 22, 28, and 37 mm at a delay time of 100 minutes, 80.4%, 99.5%, 107.9%, 113.1%, 128.0%, and 124.8%, respectively were measured. When the moving distance was the same, the difference according to the respiratory rate was insignificant. When the number of breaths is 20 and the moving distance is 1 cm, 2 cm, 3 cm, and 5 cm, as the moving distance increased at the sphere diameters of 10, 13, 17, 22, 28, and 37 mm, the ability to distinguish images from smaller spheres deteriorated. When the moving distance is 5 cm compared to the still image, the maximum values of the standard intake coefficient were 18.0%, 23.7%, 29.3%, 38.4%, 49.0%, and 67.4% for sphere diameters of 10, 13, 17, 22, 28, and 37 mm, respectively.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.975-982
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• 2021

The purpose of this study is to evaluate the effect on the phantom for magnetic resonance imaging located nearby by partially shielding RF with a mesh made thinner than hair composed of copper, black metal, and polyester using metallic materials of titanium, which are commonly used for esophageal stents and implants in the body. Magnetic resonance images according to field of view (FOV) were analyzed in the Spin Echo T1 weighted images of TR 500 ms, TE 20 ms, NEX 1, and slice thickness 5mm using a Cardiac coil of 3T Achieva X-series. Aliasing artifact did not occur in FOV 304 mm × 304 mm, but it occurred in 250 mm × 250 mm and 170 mm × 170 mm. In FOV 170 mm × 170 mm, when a mesh was not used, the SNR was measured with 78.23, and when separated by standing a mesh in the middle, it was 215.05, and when completely shielded with a mesh, the SNR was 366.44. In addition, when completely shielded with a mesh, the aliasing artifact was also removed, and signal intensities on the left, middle and right of the image were also able to obtain homogeneous images compared to the previous two cases. In conclusion, if RF is partially shielded with a mesh, aliasing artifact can be removed, and magnetic resonance images with excellent image resolution and homogeneity can be obtained using a small FOV.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.899-909
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• 2021

In Musculoskeletal ultrasound examination, a linear transducer (12-5 MHz) with a contact surface length of 6 cm, which is commonly distributed in medical institutions, does not contact with bent fingers and wrist depressions only by using a conventional liquid ultrasound gel, which causes image loss. In order to solve this image loss, the use of commercially available Water gel pad is increasing. However, it is a disposable medical product. Repeated use is prohibited and expensive. In this study, in order to reduce the economic burden caused by the use of the commercialized Water gel Pad, we searched for water-soluble food thickener powder that can be easily purchased around our lives and manufactured Gel pads. Among them, kappa-Carrageenan Gel Pad, iota-Carrageenan Gel Pad, and Agar-Agar Gel Pad satisfied the evaluation criteria without artifacts in image evaluation using the N-365 Multipurpose Phantom. Also, the price to purchase the food thickener powder was about 38 times cheaper than the existing commercialized Water gel pad. As a result, if you use the food thickener powder such as kappa-Carrageenan, iota-Carrageenan and Agar-Agar to make solidified elastic Gel pad without a cover instead of the commercially available expensive disposable Water gel pad, the convenience and usefulness of use are improved. It is judged that the manufactured Gel pads can contribute well to the role of efficient ultrasound propagation medium.

• Journal of Digital Forensics
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• v.12 no.3
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• pp.109-120
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• 2018

The smartphone is the communication device that is the most personal to the user, and it keeps a lot of information related to the user and makes information communication with other devices. With these characteristics, forensics on smartphones are one of the most basic methods of investigation in criminal investigations, and have actually contributed to the settlement of the case by providing many clues. However, recently, it is designed to encrypt data stored as a social issue related to the protection of user's personal information, or to delete deleted data or to delete log data together. So, any solutions? In this paper, I try to find the answer from cloud data stored by smartphone user account. Cloud forensics should approach complementary relationships rather than smartphone forensics. There are a lot of data stored in the cloud that can be meaningfully used in the investigation. Online activity information of users, such as Internet usage, YouTube view, and contents purchase information, cloud service such as e-mail, cloud drive, and location information are the most representative data. These data can be unvaluable, but here are some important clues in various types of criminal investigations. In this paper, I propose a method to extract data from the google cloud so that the data can be used for investigation, and to utilize the extracted data for investigation. And it explains the role of the extracted artifacts in the actual investigation business through virtual cases and proves its value.

• Cross-Cultural Studies
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• v.49
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• pp.303-330
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• 2017

This paper examines the origin of the current Nigerian Yoruba artistic and cultural tradition through ancient artifacts and creation myths centered on $Il{\acute{e}}-If{\acute{e}}$ (or $If{\acute{e}}$) located in the southwestern part of Nigeria and recognition of cultural relativity. In the oral tradition, kingdoms of Ijebu, Oyo, and Benin all have their origins in the ancient city of $Il{\acute{e}}-If{\acute{e}}$, the cradle of Yoruba culture. Their founders were sons of Oduduwa, the god of Yoruba. In this way, kingdoms built around $Il{\acute{e}}-Ife$ were closely connected with culture, religion, and society. In order to understand the Yoruba culture, research on $Il{\acute{e}}-Ife$, the source of their artistic and cultural traditions, is very important. The Yoruba are deeply rooted in $Il{\acute{e}}-Ife$. They have been steadily preserving their artistry since the beginning. They have been using it in their lives to this day for centuries. Their evidences are mythology and Ifa divination system. They are cultural heritages that represent the art of Yoruba and the spiritual culture. Ifa devination system is one of Yoruba traditions associated with Yoruba gods 'Eshu' and 'Ifa'. It has been conducted among the Yoruba until now. If the culture and civilization of Africa, including these Yoruba traditional customs, are deemed illogical and superstitious, it would mislead their efforts to preserve the origin in its original form. If so, one should understand the relativity of other cultures and civilizations and the need for diversity and flexibility of value standards to judge their cultures and civilizations.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.119-134
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• 2019

In order to analyze the observational environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we used the digital elevation model (DEM) and the solar radiation model to calculate a topographical shading, sky view factor (SVF) and solar radiation by surrounding terrain. The sky line and SVF were calculated using high resolution DEM around 25 km of the solar stations. We analyzed the topographic effect by analyzing overlapped solar map with sky line. Particularly, Incheon station has low SVF whereas Cheongsong and Chupungryong station have high SVF. In order to validation the contribution of topographic effect, the solar radiation calculated using GWNU solar radiation model according to the sky line and SVF under the same meteorological conditions. As a result, direct, diffuse and global solar radiation were decreased by 12.0, 5.6, and 4.7% compared to plane surface on Cheongsong station. The 6 stations were decreased amount of mean daily solar radiation to the annual solar radiation. Among 42 stations, eight stations were analyzed as the urgent transfer stations or moving equipment quickly and more than half of stations (24) were required to review the observational environment. Since the DEM data do not include artifacts and vegetation around the station, the stations need a detail survey of observational environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.96-104
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• 2018

Military vessels are complex weapon systems consisting of various integrated onboard equipment. Since their acquisition of military equipment takes a long period of time and a prototype ship is deployed and tested, vessel development has relied on its proprietary process. However, due to the growing complexity of onboard equipment technology, application of systems engineering (SE) process has become indispensable. Nonetheless, an effective design process complementing the existing design with the SE has not yet been developed. As such, we have studied an improved basic design process for submarines based on SE. To do so, we analyzed the processes for the basic design, technical review, and requirement management. Included reviews and requirements are SRR, SFR and PDR, and SSRS, SSS, and SSDD. By combining the results in the SE framework, we built an improved basic design process that can be applied in parallel with the SE-based technical review and requirement management. To assess the process, we applied our proposed model to the submarine development undergoing the basic design phase. It is possible to effectively manage the requirements, design artifacts and improve traceability, and also utilize them as test and evaluation materials. The SE-based basic design process is expected to be useful in other kinds of vessel design.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.92-101
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• 2018

It is important to inherit and develop the unique cultural characteristics of each country and region in the trend of globalization. The traditional lighting fixtures in China are the main artifacts that can be used to extract the cultural aesthetics and practicality of the people, and are a major relic of the people's cultural sensitivities and practicalities. The purpose of this study is to understand the background of the time and the meaning of national culture through the lighting equipment of the most revived Tang Dynasty in Chinese history. The purpose of this paper is to examine the development trend of lighting equipment in the Tang Dynasty through the recognition of the social background, religious thought, cultural characteristics, and characteristics of lighting fixtures in the Tang Dynasty. In this paper, we analyzed seven factors (function, molding, fuel, usage space, usage method, religious thought, and living environment) of the Tang dynasty lighting fixtures through multiple factor analysis method. In addition, the Tang Dynasty period lighting fixtures had four trends: "popularization of lighting, universal simplification of molding, diversification of use, and spread of Buddhist influence." This tendency has a meaning to provide a new motive for modern lighting design in the context of cultural uniqueness and perspectives.

• Journal of Conservation Science
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• v.34 no.6
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• pp.493-502
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• 2018

Currently, the fabrication of a high-tin bronze spoon by traditional manufacturing techniques involves 10 steps in the bronze ware workshop. Hot forging has a major influence on manufacturing and involves two to three steps. The dendritic ${\alpha}$-phase in the microstructure of the high-tin bronze spoon is refined and finely dispersed through hot forging. In addition, twinning is observed in the ${\alpha}$-phase of the hammered part, and the ${\alpha}$-phase microstructure gradually transform from a polygon to a circular shape due to hammering. In this process, the adjacent ${\alpha}$-phases overlap with each other and remain combined after quenching. The microstructure with the overlapping is also observed in bronze artifacts, and this shows the correlation with technical system. The results of the experimental hot forging of Cu-22%Sn alloys show that the decrease in in the amount of the dendritic microstructure, which forms during casting, is in proportion to the number of processing steps and that the refined grain obtained by hammering contributes to the improvement in the strength of the material. From the hammering marks, which are observed on both the bronze artifact excavated from archaeological sites and on the high-tin bronze spoon produced in the traditional workshop, it is presumed that the knowledge regarding the unrecorded manufacturing system of bronze ware in ancient times has been passed down in a traditional way up to the system used currently.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.88-104
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• 2009

Changes in a society and visual media has a tight relationship. Photography represented the last 20th century in the visual media; while the 21st century we live in is represented by moving image(video). The change of visual media also brought changes to the archaeological recordings. As information is gathered from the field work in archaeology, it seems that use of video recording, a reliable way of collecting and recording data, will increase. The process of archaeological excavations can be considered as a contents itself. Also, video recording has many advantages when recording environmental surrounding of the sites and artifacts, for the reservation of the scenery, and as recorded heritage of the humankind. Video recording can be a tool of conversion to public archaeology to devote to its social and academic roles. Considering all of the above, studying ways to record and preserve visual materials is essential in the field of archaeology and we should be prepared for it. We strongly propose reinstatement of the visual archaeology, which should be studied in archaeological perspective. The direction of the study of visual archaeology can be summarized into two. First is the study on the video recording during field work and the archive of video recordings. Second is the study on the media as the tool of communication. More detailed and organized research should be considered in depth in the archaeological theory and methods.