• Journal of radiological science and technology
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• v.44 no.3
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• pp.247-252
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• 2021

As the number of single-person households increases, the consumption of bottled water is increasing. In addition, as the public's interest in radioactivity increases, interest in the field of living radioactivity is also increasing. Since drinking water is an essential element in our daily life, it must be safe from radioactivity. In this study, gamma radiation of drinking spring water was measured and internal exposure dose evaluation was performed to determine its harmfulness. K-40 and uranium-based radioactivity analysis was performed through a high-purity germanium detector, and as a result, drinking water was detected somewhat higher than that of mixing water. Since there is no regulation on the natural radioactivity concentration in Korea, it was compared with the U.S. Environmental Protection Agency Drinking Water Regulations and World Health Organization standard. As a result, there were some items that exceeded standards. Internal exposure was evaluated according to the effective dose formula of ICRP 119. As the result was derived that a maximum of 1.17 mSv per year could be received. This result means that the dose limit for the general public may be exceeded, and it was judged that it is necessary to set an appropriate standard value and present a recommendation value through continuous monitoring in the future.

• Journal of The Korean Association of Information Education
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• v.25 no.3
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• pp.511-525
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• 2021

The purpose of this study is to develop a design guideline to provide user-friendly experience and convenience for the online support system for the curriculum at primary/secondary schools. To achieve the objective, best practices of overseas on the online support system for curriculum as well as prior research were analyzed. In addition, UX/UI usability problems and needs were derived through a survey of 74 professionals and teachers who are monitoring NCIC and high school credit system sites. Based on the analysis of best practices of overseas and survey results, the draft of the design guideline was derived, and Delphi method was conducted by experts to re- vise the design guidelines and evaluate their validity. This study is meaningful in that it suggests the direction of improvement of the system currently being serviced and the direction of the design of the system to be developed in the future, by providing design guidelines that can be generally applied to online support systems that perform tasks related to the curriculum.

• The Journal of Korean Obstetrics and Gynecology
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• v.34 no.2
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• pp.16-30
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• 2021

Objectives: The aim of this study was to establish a clear diagnostic definition of Sanhupung using the Delphi method. Methods: This study used the Delphi technique. A panel consisting of 21 experts of Korean medicine, particularly in of gynecologic medicine, participated in the Delphi examination that included answering the 4th round survey. The Delphi examination was carried out through evaluating and correcting the questionnaire by e-mail. Results: Through the Delphi survey, we have reached on an agreement regarding the basic concepts, time, cause, essential symptoms, and accessory symptoms of Sanhupung. They are as follows: 1) Sanhupung is a culture bound syndrome reflecting Korea's cultural specificity. 2) Sanhupung can be diagnosed even after the miscarriage. 3) For the diagnosis of Sanhupung, the main cause of symptoms should not be classified as other disease. 4) Sanhupung can be diagnosed based on essential symptoms and accessory symptoms. 5) Essential symptoms include local symptoms such as joint pain at specific areas, partial sensory impairment and general symptoms including pain of all the joints, whole body sensory impairment, increased sweating, feeling of wind coming into the body, worsened symptoms with the cold, intolerance to cold, and pain of all the muscles. Conclusions: The basic concepts and diagnostic definition of Sanhupung were suggested based on the Delphi survey among experts in the field. Further research is necessary to improve reliability and validity of diagnostic definition of Sanhupung in clinical trials.

• The Journal of Korean Medicine
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• v.42 no.2
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• pp.50-61
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• 2021

Objectives: The object of this study was to examine whether there was a significant difference between morning and afternoon in heart rate variability(HRV) in healthy Korean adults. In addition, the correlation between the characteristics of the subjects and the test results was analyzed. Methods: From January 8, 2021 to January 29, 2021, twenty healthy subjects received short-term HRV test once in the morning(6:00~12:00) and twice in the afternoon(12:00~18:00). We used IBM SPSS Statistics 27 to test for statistical significance. Results: The mean heart rate and PSI decreased significantly and SDNN increased significantly in the morning compared to the afternoon. There was no significant difference except RMSSD in HRV conducted at 2 hours intervals in the afternoon. Age had a significant difference in SDNN and TP, and exercise in average heart rate. Age, weekly exercise frequency, and monthly drinking frequency showed significant correlations with HRV indicators. As a result of multiple regression analysis, monthly drinking frequency was a variable that had a significant influence on TP. Conclusions: The results of the tests performed with short interval were relatively consistent, and when comparing the results of the afternoon and the next morning, there were significant differences in several indicators. In the future, the number of HRV measurements should be increased and a larger-scale follow-up study including more subjects will be needed.

• Journal of IKEEE
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• v.26 no.4
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• pp.705-709
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• 2022

The effect of the annealing temperature of the poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) solid electrolyte layer on the electrical properties of the P(VDF-TrFE)-based memristor was analyzed. In morphological analyses, the P(VDF-TrFE) thin film with 200℃ annealing temperature (200P(VDF-TrFE)) was shown to have surface roughness ≈5 times larger and thickness ≈20% smaller than that with 100℃ annealing temperature (100P(VDF-TrFE)). Compared to the 100P(VDF-TrFE) memristor (M100), the set voltage of the 200P(VDF-TrFE) memristor (M200) decreased by ≈50% and the magnitude of its reset voltage increased by ≈30%. Moreover, M200 was found to have better memory retention characteristics than M100. These differences were attributed to relatively strong local electric fields inside M200 compared to M100. This study suggests the importance of the annealing temperature in polymer memristors.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.513-520
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• 2022

The purpose of this study was to investigate the effect of Cheonggukjang pills with aronia and blueberries on dextran sulfate sodium (DSS)-induced colitis in mice. There have been several reports that Cheonggukjang is effective for intestinal health, but the efficacy of Cheonggukjang containing fruits has not yet been reported. In this study, we showed the effect of cheonggukjang pills with blueberries and aronia (CPBA) on DSS-induced colitis in BALB/c mice. CPBA was obtained from Soonchang Moonokae foods and orally administered once a day for 2 weeks before DSS treatment. Colitis was induced in mice by feeding 5% (w/v) DSS drinking water for 7 days. The results showed that CPBA treatment significantly alleviated DSS-induced disease activity index associated with a decrease in colon length. CPBA improved DSS-induced histological changes and intestinal epithelial barrier integrity in mice colon. In addition, CPBA administration significantly reduced the levels of DSS-mediated interferon-γ and interleukin-6 in serum and tumor necrosis factor-α in colon tissue. Moreover, the gene expression of COX-2 and iNOS, which are factors involved in inflammatory signaling, was significantly reduced by CPBA treatment. These results suggest that CPBA have a protective effect against DSS-induced mice colitis and may be a candidate for colitis treatment.

• Design Convergence Study
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• v.15 no.4
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• pp.1-16
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• 2016

Healthcare service helps users' health management by collecting an individual user's activity and biometric data from mobile devices and by providing them to the user. As a result, it has become necessary to perform a research on how to show the collected data. According to information visualization, the same data can have various interpretations depending on how they are represented. Healthcare data must be elivered to information acceptors without errors or distortion as they are directly related to people's health. With the expansion of healthcare service by the development of technology, this study could measure various data from users and was started to provide a necessary guideline for the visualization of measured numerical data. To propose a specific visualization by applying the visualization direction, 5 types of data including present value, measured value, relative value, relation data, and prediction value were set as the values necessary for the continuous use of mobile healthcare. Visualization was proposed concretely by applying clarity, variable comparison, brevity, relation, reliability, independence, and contextuality, which are the criteria for vitalizing the healthcare service.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.1-10
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• 2023

Recently, as the demand for high-performance computers and mobile products increases, semiconductor packages are becoming high-integration and high-density. Therefore, in order to transmit a large amount of data at once, micro bumps such as flip-chip and Cu pillar that can reduce bump size and pitch and increase I/O density are used. However, when the size of the bumps is smaller than 70 ㎛, the brittleness increases and electrical properties decrease due to the rapid increase of the IMC volume fraction in the solder joint, which deteriorates the reliability of the solder joint. Therefore, in order to improve these issues, a layer that serves to prevent diffusion is inserted between the UBM (Under Bump Metallization) or pillar and the solder cap. In this review paper, various studies to improve bonding properties by suppressing excessive IMC growth of micro-bumps through additional layer insertion were compared and analyzed.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.328-333
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• 2023

This study experimentally verified the etch rate of the SiO₂ sacrificial layer etching process with a single etch hole using vapor-phase hydrogen fluoride (VHF) etching. To fabricate small-sized polysilicon etch holes, both circular and triangular pattern masks were employed. Etch holes were fabricated in the polysilicon thin film on the SiO₂ sacrificial layer, and VHF etching was performed to release the polysilicon thin film. The lateral etch rate was measured for varying etch hole sizes and sacrificial layer thicknesses. Based on the measured results, we obtained an approximate equation for the etch rate as a function of the etch hole size and sacrificial layer thickness. The etch rates obtained in this study can be utilized to minimize structural damage caused by incomplete or excessive etching in sacrificial layer processes. In addition, the results of this study provide insights for optimizing sacrificial layer etching and properly designing the size and spacing of the etch holes. In the future, further research will be conducted to explore the formation of structures using chemical vapor deposition (CVD) processes to simultaneously seal etch hole and prevent adhesion owing to polysilicon film vibration.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.35-42
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• 2024

Recently, with the miniaturization and high integration of semiconductor chips, the bump bridge phenomenon caused by fine pitches is drawing attention as a problem. Accordingly, Cu pillar bump, which can minimize the bump bridge phenomenon, is widely applied in the semiconductor package industry for fine pitch applications. When exposed to a high-temperature environment, the thickness of the intermetallic compound (IMC) formed at the joint interface increases, and at the same time, Kirkendall void is formed and grown inside some IMC/Cu and IMC interfaces. Therefore, it is important to control the excessive growth of IMC and the formation and growth of Kirkendall voids because they weaken the mechanical reliability of the joints. Therefore, in this study, isothermal aging evaluation of Cu pillar bump joints with a CS (Cu+ Sn-1.8Ag Solder) structure was performed and the corresponding results was reported.