• Journal of radiological science and technology
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• v.44 no.4
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• pp.295-300
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• 2021

This study aims to present new chest AP examination exposure conditions through a study on the effect on image quality and patient dose by applying high tube voltage and scatter ray post-processing software during chest AP examination in digital radiography equipment. This study was used a human body phantom and in the chest AP position, the dosimeter was placed horizontally at the thoracic spine 6. The experiment was conducted by dividing into a low tube voltage (70 kVp, 400 mA, 3.2 mAs) group and a high tube voltage (100 kVp, 400 mA, 1.2 mAs) group. The collimation size (14″× 17″) and the source to image receptor distance(110 cm) were same applied to both groups. Radiation dose was presented to dose area product and entrance surface dose. Image quality was compared and analyzed by comparing the difference between the signal-to-noise ratio and the contrast-to-noise ratio of the image according to the application of the scatter ray post-processing software under each condition. The average value of the entrance surface dose in the low and high tube voltage conditions was 93.04±0.45 µGy and 94.25±1.51 µGy, which was slightly higher in the high tube voltage condition, but the dose area product was 0.97±0.04 µGy and 0.93±0.01 µGy. There was a statistically significant difference in the group mean value(p<0.01). In terms of image quality, the values of the signal-to-noise ratio and the contrast noise ratio were higher in the high tube voltage than in the low tube voltage, and decreased when the scattering line post-processing function was used, but the contrast resolution was improved. If there is a scatter ray post-processing function during chest AP examination, it is helpful to actively utilize it to improve the image quality. However, when this function is not available, I thought that applying a higher tube voltage state than a low tube voltage state will help to realize images with a large amount of information without changing the dose.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.311-321
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• 2019

Greenhouse farmers often use thermal screens to reduce greenhouse heating expenses during the winter, and for shade during hot, sunny days in the summer, as it is an inexpensive solution to temperature control relative to other available options. However, accurate measurements of their emitted and absorbed radiations are important for the selection of suitable screens that offer maximum performance. Material's ability to save energy is highly dependent on these properties. Limited studies have investigated the measurement of these properties under natural conditions, but they are only applicable to materials having partial porosities. In this work, we describe a new radiation balance method for determining emissive power and absorptive capacity, as well as reflectivity, transmissivity and emissivity of materials having complete and partial transparency by using pyrgeometer and net radiometer. In this study, four materials with zero porosity, were tested. The emissivity value of PE, LD-13, LD-15 and PH-20 was $0.439{\pm}0.020$, $0.460{\pm}0.010$, $0.454{\pm}0.004$, and $0.499{\pm}0.006$, respectively. All tested samples showed high emitted radiation as compared to absorbed radiation.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.21-35
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• 2020

Due to the coronavirus pandemic and diplomatic disputes, governments are actively developing a policy to revitalize·reshore manufacturing and to diversify international cooperations. In order to develop such a policy, it is very important to compare and analyze domestic·international geospatial information. Over the decade, the US·EC governments have conducted a series of national researches to build data-based tools that can monitor·analyze regional geospatial information driven by government R&D investments. In the case of the EC system, it can compare geospatial information in domestic and international(including Korea) regions. Compared to US·EC cases, Korean examples of national researches with available data analplatform need future improvements. Current study is investigating an automated analysis methodologies using "National Institute of Science and Technology Information (NTIS)" DB, which was national security data until recently. Research on data-mining regional geospatial information can contribute to support policy fields that need to discover new issues in response to unexpected social problems such as recently faced corona and trade disputes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.79-86
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• 2021

In order to increase the probability of success in big data projects, quantified techniques are required to analyze the root cause of risks from complex causes and establish optimal countermeasures. To this end, this study measures risk factors and relationships through SNA analysis and presents a way to respond to risks based on them. In other words, it derives a dependency network matrix by utilizing the results of correlation analysis between risk groups in the big data projects presented in the preliminary study and performs SNA analysis. In order to derive the dependency network matrix, partial correlation is obtained from the correlation between the risk nodes, and activity dependencies are derived by node by calculating the correlation influence and correlation dependency, thereby producing the causal relationship between the risk nodes and the degree of influence between all nodes in correlation. Recognizing the root cause of risks from networks between risk factors derived through SNA between risk factors enables more optimized and efficient risk management. This study is the first to apply SNA analysis techniques in relation to risk management response, and the results of this study are significant in that it not only optimizes the sequence of risk management for major risks in relation to risk management in IT projects but also presents a new risk analysis technique for risk control.

• The Mathematical Education
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• v.61 no.4
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• pp.521-537
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• 2022

The unprecedented COVID-19 pandemic has disrupted, interrupted, and changed the way we normally prepare our teacher candidates in teacher preparation programs. In this paper, we, two mathematics teacher educators (MTEs), reflect our own experiences in appropriating, transforming, reconstructing, and modifying our pedagogies of teacher education in making a transition from face-to-face to online environment during the COVID-19 pandemic. Using a collaborative self-study, we discussed issues, challenges, changes, opportunities, and innovations of teaching an elementary mathematics methods course in the online environment. Using a constant comparison method, we explored the following three themes: (1) using virtual manipulatives; (2) creating collaborative, interactive, and shared learning experiences for preservice teachers; and (3) making preservice teachers engaged in student thinking. These findings indicated that online teaching requires transformative knowledge for teacher educators. Transferring face-to-face to online is not a simple matter of putting the existing content to online; it should focus on pedagogical improvement in teaching mathematics rather than technology's sake or how it can be repurposed in a new online environment in a way that students' learning is optimized. The findings of this study provide implications for unpacking MTEs' technological pedagogical content knowledge (TPACK), creating collaborative learning experiences for preservice teachers, and designing a collaborative self-study between MTEs engaged in the community of professional learning.

• Journal of Navigation and Port Research
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• v.45 no.1
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• pp.26-32
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• 2021

In ocean field, the spread of the Fourth Industrial Revolution based on information and communication technology requires high precision and stable PNT&D (Position, Navigation, Timing and Data). As the IMO (International Maritime Organization) and IALA (The International Association of Marine Aids to Navigation and Lighthouse Authorities) are requiring backup systems due to mitigate vulnerabilities and the increase of dependency on GNSS (Global Navigation Satellite System), Korea is conducting a research & development of R-Mode. An DGPS (Differentiate Global Positioning System) reference station that uses MF, an existing maritime infrastructure, and AIS (Automatic Identification System) base stations that use 34 integrity station and VHF will be utilized in this study to avoid redundant investment. Because there are radio shadow areas that display low signal levels in the west sea, the establishment of new R-Mode reference and integrity station will be intended to resolve problems regrading the radio shadow area. Because the frequency has a characteristic in that radio wave transmits well along the ground (water surface) in low frequency band, simulation and measurement were conducted therefore this paper to propose candidate sites for R-Mode reference and integrity station resulted through p wave's propagation characteristics analysis. Using this paper, R-Mode reference and integrity station can be established at appropriate locations to resolve radio shadow areas in other regions.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.194-200
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• 2021

The aim of this study was proceed for 6weeks to determine the effect of middle-aged women's upper lips ms by SUKI programs. A total of 20 subjects were tested, and the SUKI arbitration programs of Pattern T1, Pattern T2, Pattern T3, Pattern T4 were adopted three times a week in six weeks. The results were as this. It showed a significant difference in the EG, although some of the intra-group comparisons of the upper lip ms. Therefore, SUKI programs have been shown to help improve the elasticity of the upper lip ms(p<.05). In this study, the SUKI program was used based on the fact that although limited, the elasticity of the upper lip ms, located in the facial part of a middle-aged woman, causes various wrinkles around her mouth, making them lose confidence in their appearance. This also suggests that normal facial ms can affect the appearance of the female middle-aged woman, and it was intended to suggest some ways to manage the appearance by proper management of facial muscle according to the life cycle of the female middle-aged woman. In conclusion, we hope that in the future, various experiments will be used as new research data on how to prevent women's facial skin beauty and wrinkles and help improve elasticity of facial muscles around the mouth.

• Korean Journal of Construction Engineering and Management
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• v.22 no.2
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• pp.106-118
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• 2021

Global governments and initiatives have attempted and integrated various organizational efforts to implement the 17 Sustainable Development Goals (SDGs), presenting a new paradigm of sustainable development to address global issues (climate change, poverty eradication, and human rights). Recently, investment in sustainable finance has expanded to finance the attainment of goals set out in the Paris Agreement and SDGs. Non-financial factors such as environment, social responsibility, and governance (ESG) have become intangible assets that determine the future competitiveness and profitability of companies. Domestic and foreign institutional investors and asset management companies have been expanding their investments based on the ESG performance of companies. In this study, we aim to derive international standards and initiatives that require disclosure of information on corporate social responsibility activities and ESG performance and analyze construction companies' ESG activities and performance levels. The results of this study can be used as the basis to develop platforms for the construction industry ESG ecosystem and the measurement and management of intangible assets. These could ultimately contribute to overcoming the crisis in the future due to the outbreak of the COVID-19 pandemic, fostering net-zero emissions, and preventing fatal workplace accidents in the construction industry.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.595-606
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• 2020

To find out the a Study on experiential consumption and development of the customized cosmetics on female university students in their 20s, this study conducted sampling using probability sampling from cosmetics major students in S City from September 1 to October 30, 2020. In this study, a study model was designed for a total of 30 people and studied as an Experience-Consume Experimentation. First, the result of the pre-purchase survey revealed that skincare cosmetics had the highest percentage for being selected by 30 people for "the preferred cosmetic type per the perception regarding customized cosmetics." Second, the result of the pre-purchase survey revealed that 11 people answered skincare cosmetics, 1 person answered shade cosmetics, and 2 people answered fragrance products (perfume, diffusers, etc.) for "the experience type for customized cosmetics." Third, the result of the post-purchase survey revealed that 29 people are willing to recommend the products, while 1 person is not. For the appropriateness of the price, 23 people answered yes; 7 people answered no. for the characteristics of the experience, 24 people (80%) answered that they selected ingredients according to their skin type; 9 people answered that the price is cheap considering they received 1:1 consultation; 18 people answered that they made a choice per their preferences (skin type) rather than per brands; 3 people answered that their self-esteem is stronger as if they received personal care. Therefore, customized cosmetics are expected to increase the attractiveness and purchase rate of female students in their twenties given that 'Human Touch,' genetic analysis, and 'hyper-customization technology,' which requires new development of customized cosmetics experience consumption for female college students in their 20s.

• Resources Recycling
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• v.30 no.3
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• pp.70-81
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• 2021

This study evaluated the recyclability of waste plastics in used coffee capsules disposed of as municipal waste. For recycling, a new material separation process was developed to remove the coffee grounds through primary crushing, washing, sieving, and secondary crushing, followed by corona discharge electrostatic separation. Furthermore, for the under 10 mm size fraction samples, the aluminum removal and the plastic recovery were 95.4% and 98.3%, respectively, under optimal conditions. In addition, for the 15 mm fraction samples, the aluminum removal and the plastic recovery were 91.3% and 97.2%, respectively. To evaluate the recyclability of the separated waste plastics, the samples were pelleted, and their material properties were analyzed. No hazardous substances were detected, and the results were similar to those for homo-PP. Therefore, it was confirmed tha t sufficient functiona lity existed a s recycled PP. However, owing to the da rk color of the pellets, limited applications to black or dark products are expected.