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다전략 수학 문제해결 학습이 초등학생의 수학적 창의성과 수학적 태도에 미치는 영향
김서령 ( Kim¸ Seoryeong ),박만구 ( Park¸ Mangoo ) 한국수학교육학회 2021 初等 數學敎育 Vol.24 No.4
The purpose of this study is to investigate the effects of solving multi-strategic mathematics problems on mathematical creativity and attitudes of the 6th grade students. For this study, the researchers conducted a survey of forty nine (26 students in experimental group and 23 students in comparative group) 6th graders of S elementary school in Seoul with 19 lessons. The experimental group solved the multi-strategic mathematics problems after learning mathematics through mathematical strategies, whereas the group of comparative students were taught general mathematics problem solving. The researchers conducted pre- and post- isomorphic mathematical creativity and mathematical attitudes of students. They examined the t-test between the pre- and post- scores of sub-elements of fluency, flexibility and creativity and attitudes of the students by the i-STATistics. The researchers obtained the following conclusions. First, solving multi-strategic mathematics problems has a positive impact on mathematical creativity of the students. After learning solving the multi-strategic mathematics problems, the scores of mathematical creativity of the 6th grade elementary students were increased. Second, learning solving the multi-strategy mathematics problems impact the interest, value, will and efficacy factors in the mathematical attitudes of the students. However, no significant effect was found in the areas of desire for recognition and motivation. The researchers suggested that, by expanding the academic year and the number of people in the study, it is necessary to verify how mathematics learning through multi-strategic mathematics problem-solving affects mathematical creativity and mathematical attitudes, and to verify the effectiveness through long-term research, including qualitative research methods such as in-depth interviews and observations of students' solving problems.
Park, Seoryeong,Boo, Jiwhan,Hammig, Mark,Jeong, Manhee Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.4
The mask parameters of a coded aperture are critical design features when optimizing the performance of a gamma-ray camera. In this paper, experiments and Monte Carlo simulations were performed to derive the minimum detectable activity (MDA) when one seeks a real-time imaging capability. First, the impact of the thickness of the modified uniformly redundant array (MURA) mask on the image quality is quantified, and the imaging of point, line, and surface radiation sources is demonstrated using both cross-correlation (CC) and maximum likelihood expectation maximization (MLEM) methods. Second, the minimum detectable activity is also derived for real-time imaging by altering the factors used in the image quality assessment, consisting of the peak-to-noise ratio (PSNR), the normalized mean square error (NMSE), the spatial resolution (full width at half maximum; FWHM), and the structural similarity (SSIM), all evaluated as a function of energy and mask thickness. Sufficiently sharp images were reconstructed when the mask thickness was approximately 2 cm for a source energy between 30 keV and 1.5 MeV and the minimum detectable activity for real-time imaging was 23.7 MBq at 1 m distance for a 1 s collection time.
Park Seoryeong,Hammig Mark D.,Manhee Jeong 대한방사선방어학회 2022 방사선방어학회지 Vol.47 No.4
Background : The conventional cerium-doped Gd2Al2Ga3O12 (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gamma-ray source if the shielding against background radiation is not appropriately designed . In addition , portability is important in complex environments such as inside nuclear power plants , yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle . Motivated by the need to develop a system that is not sensitive to background radiation and is portable , we changed the material of the scintillator and the coded aperture . Materials and Methods : The existing GAGG(Ce) was replaced with Bi4Ge3O12 (BGO) , a scintillator with high gamma-ray detection efficiency but low energy resolution , and replaced the tungsten (W) used in the existing coded aperture with lead (Pb) . Each BGO scintillator is pixelated with 144 elements (12 × 12) , and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5 , 10 , and 20 mm) . A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses . Results and Discussion : Spectroscopic characterization , imaging performance , and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance . Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system’s overall weight can be reduced . Conclusion : Despite the spectral characteristics , imaging system performance , and image quality is slightly lower than that of GAGG(Ce) , the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment , and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.