• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.563-581
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• 2010

In this paper, we perform subjective visual quality assessments on UHD video for UHD TV services and analyze the assessment results. Demands for video services have been increased with availabilities of DTV, Internet and personal media equipments. With this trend, the demands for high definition video have also been increasing. Currently, 2K-HD ($1920{\times}1080$) video have been widely consumed over DTV, DVD, digital camcoders, security cameras and other multimedia terminals in various types, and recently digital cinema contents of 4K-UHD($3840{\times}2160$) have been popularly produced and the cameras, beam projects, display panels that support for 4K-UHD video start to come out into multimedia markets. Also it is expected that 4K-UHD service will appear soon in broadcasting and telecommunications environments. Therefore, in this paper, subjective assessments of visual quality on resolutions, color formats, frame rates and compression rates have been carried to provide basis information for standardization of signal specification of UHD video and viewing environments for future UHDTV. As the analysis on the assessments, UHD video exhibits better subjective visual quality than HD by the evaluators. Also, the 4K-UHD test sequences in YUV444 shows better subjective visual quality than the 4K-UHD test sequences in YUV422 and YUV420, but there is little perceptual difference on 4K-UHD test sequences between YUV422 and YUV420 formats. For the comparison between different frame rates, 4K-UHD test sequences of 60fps gives better subjective visual quality than those of 30fps. For bit-depth comparison, HD test sequences in 10-bit depth were little differentiated from those in 8-bit depth in subject visual quality assessment. Lastly, the larger the PSNR values of the reconstructed 4K-UHD test sequences are, the higher the subjective visual quality is. Against the viewing distances, the differences among encoded 4K-UHD test sequences were less distinguished in longer distances from the display.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1451-1456
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• 2004

Amino acid transporters play an important role in supplying nutrients to normal and cancer cells for cell proliferation. System L is a major transport system responsible for the $Na^+$ -independent, large neutral amino acids including several essential amino acids. L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed presumably to support their continuous growth and proliferation in malignant tumors. In the present study, we have examined the correlation between the expressions of amino acid transporter LAT1 mRNA and its subunit 4F2hc mRNA and the amount of L-leucine transport in various human cancer cell lines. Northern blot analysis have revealed that the 26 human cancer cell lines expressed LAT1 mRNA and 4F2hc mRNA. There were the differences for the levels of LAT1 and 4F2hc mRNA expressions in the 26 human cancer cell lines. The 26 human cancer cell lines transported the L-[$^{14}C$]leucine into the cells via amino acid transporter. In the 26 human cancer cell lines, a linear relationship was observed between the expression of amino acid transporter LAT1 mRNA and the amount of L-leucine transport. Little relationship was observed between the expression of 4F2hc mRNA and the amount of L-leucine transport, but the statistical significance of difference was not detected. These results indicate that the 26 human cancer cell lines express LAT1 mRNA and 4F2hc mRNA and there is the correlation between the expression of amino acid transporter LAT1 mRNA and the amount of L-leucine transport. In addition, specific inhibition of LAT1 in cancer cells will be a new rationale for anti-cancer therapy.

• The Korean Journal of Nuclear Medicine
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• v.30 no.3
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• pp.361-366
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• 1996

This study was to determine the effect of $Al^{3+}$ in $^{99m}Tc$ eluate from $^{99}Mo-^{99m}Tc$ generator on labeling efficiency and biodistribution of $^{99m}Tc$-MDP. The chromatographic analysis of $^{99m}Tc$-MDP preparations containing $Al^{3+}(0-62.5{\mu}g/ml)$ showed decreased labeling efficiency $^{99m}Tc$ pertechnetate and hydrolyzed reduced $^{99m}Tc$ fraction increased with increasing concentrations of aluminum. However, the chromatography system could not discern between hydrolyzed reduced $^{99m}Tc$ and $^{99m}Tc$ labeled colloid. $^{99m}Tc$-MDP preparations containing aluminum were relatively stable. Chromatographic analysis also confirmed that no significant differences were observed in the radiochemical purity of the filtered and the unfiltered $^{99m}Tc$-MDP preparations containing aluminum by $0.22{\mu}m$ syringe filter. In biodistribution data of ICR-mice, blood and heart uptake were increasing with increasing concentrations of aluminum, because of decreasing labeling efficiency of $^{99m}Tc$-MDP and increasing of $^{99m}Tc$ pertechnetate. However, liver and bone uptake were not significantly increased. In rat images no difference were observed at $5{\mu}g/ml\;Al^{3+}$ compare with at $0{\mu}g/ml\;Al^{3+}$, but at $10{\mu}g/ml\;Al^{3+}$ lumbar uptake was increased. As a practical conclusion, a concentration below $10{\mu}g/ml\;Al^{3+}$($10{\mu}g/ml\;Al^{3+}$ is the maximum allowed in pertechnetate eluate from $^{99}Mo-^{99m}Tc$ generator by USP.) in $^{99m}Tc$-MDP radiopharmaceutical result in low labeling efficiency. Radiochemical purity 90% of $^{99m}Tc$-MDP is the minimum allowed by USP. Therefore, when soft tissue uptake is observed in $^{99m}Tc$-MDP bone scan and labeling efficiency is above 90%, we can expect that $Al^{3+}$ in pertechnetated eluate is not the cause of soft tissue uptake.

• Radiation Oncology Journal
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• v.14 no.3
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• pp.229-236
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• 1996

Purpose : To evaluate the changes of differential counts and lymphocyte subsets in cancer patients' leukocyte before and after radiotherapy. Materials and Methods : From Dec. 1994 to Mar 1995, the changes of leukocyte and its subsets in 16 patients who received radiotherapy in the Dept. of Radiation Oncology of Dong-A University Hospital were investigated. Radiation was delivered from 2700 cGy to 6660 cGy with median dose of 5400 cGy. The results of pre- and Post-radiotherapy were analyzed by paired T-test. The results of patients Who received < 50 Gy and $\geq$ 50 Gy were analyzed by Wilcoxon test. Results : Before and after radiotherapy, there was not any significant differences in the counts of leukocyte, granulocyte and monocyte. A remarkable decrease was noted in lymphocyte counts after radiotherapy(p=0.015). T cells, B cells and natural killer cells were also decreased in number after radiotherapy but it was not significant statistically. 1 helper cells and T suppressor cells were also decreased in number(p>0.05). The ratio of T helper/suppressor cell was decreased from 1.52 to 1, 11 and it was significant statistically(p=0.016). The portion of T suppressor cell among all T cells was increased after radiotherapy (p=0.0195). No significant difference was observed in the analysis of leukocyte and its subsets between patients who received < 50 Gy and $\geq$ 50 Gy, Conclusion : Radiotherapy caused remarkable decrease in lymphocyte count and its subsets. Among all lymphocyte subsets, T helper cell might be the most vulnerable to radiation, considering decreased ratio of T helper/suppressor cell count after radiotherapy.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.534-541
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• 2009

Word recognition test (WRT) for the children can be useful for diagnosing the degree of communication disability, prescribing hearing instruments, planning aural rehabilitation and speech therapy, and determination of site of lesions. The Korean standard monosyllabic word lists for preschoolers (KS-MWL-P) were developed considering the criteria given by the literatures. However, the authors of KS-MWL-P suggested more children should be included to verify homogeneity of the lists using psychometric function curve since only 8 children participated in the developing process. The purpose of this study was to explore the homogeneity of KS-MWL-P for supplementing the limitations of the lists employing psychometric analysis. To 23 preschoolers who have normal-hearing, 100 monosyllabic KS-MWL-P words were examined with the pictures. Psychometric function curve with linear slopes of 20% and 80%'s correct rates through accounting recognition scores of each monosyllabic word at variable intensities from -10 to 40 dBHL was obtained and analyzed. As a result, s-shaped psychometric function curve was presented with increasing correct rate depending on intensity and showed no statistical significant differences among each word and list. The congruous graph shapes among lists also indicated good homogeneity and the list 1,2,3,4's average slopes were 4.48, 3.86, 4.65, 4.50. It was verified that the homogeneity was suitable because the analysis of variance showed no statistical significance among lists (p>0.05). However, KS-MWL-P's order of slope according to the order of the number of items, $1{\sim}10$, $1{\sim}20$, $1{\sim}25$ showed no difference with the p-value of 0.93, 0.59, 0.91, 0.70 for the lists 1,2,3, and 4, respectively. Although KS-MWL-P was assumed that the lower-numbered items were easy for testing younger ages, this study's results could not agree with the author's conclusion. Considering this matter, rearranging of the number of items should be performed according to the analysis of slope suggested by this study for testing younger children with easier items. Other than this, in conclusion, KS-MWL-P was proved to be useful for clinical and rehabilitative evaluating and training tools for preschoolers.

• Journal of Gastric Cancer
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• v.4 no.4
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• pp.230-234
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• 2004

Purpose: The use of laparoscopic surgery for gastric disease has been gaining popularity. However, there has been the controversy over the indications and the standard techniques of laparoscopic gastric surgery in the early gastric cancer (EGC). The purposes of this study were to compare the clinical outcomes among a hand-assisted laparoscopic distal gastrectomy (HALDG), a laparoscopy-assisted distal gastrectomy (LADG), and an open distal gastrectomy (ODG) and to discuss the role of these procedures in the treatment of EGC. Materials and Methods: Between August 2001 and July 2004, laparoscopic surgery was performed in our institution on 25 patients, LADG (n=7) and HALDG (n=18) with EGC. Analysis was performed on clinical data such as the operative time, the hospital stay, the start of oral intake, and the number of harvested lymph nodes. Patients were categorized into early and late groups by using the date of surgery and were also grouped by surgical procedure. To evaluate the feasibility and efficacy of laparoscopic surgery for EGC, we compared the clinical data with those for ODGs performed during the same period. Results: There was no difference in the number of harvested lymph nodes between the laparoscopic group and the open group, but the operation time in the laparoscopic group was longer than that in the open group (P<0.05). Also, no significant differences in other clinical data were found between the two groups. Comparing the early and the late periods of the series, the number of harvested lymph nodes for a HALDS increased from $22.31\pm4.29\;to\;29.40\pm3.21$ (P<0.05). Conclusion: Our early experience with laparoscopic gastric surgery shows that a wide range of possibilities exist for applying laparoscopic gastric surgery to selected gastric cancer patients. However, the surgical procedure should be standardized, and the outcomes of laparoscopic surgery, in comparison to those of open surgery, need to be confirmed based on a large randomized study. (J Korean Gastric Cancer Assoc 2004;4:230-234)

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.3
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• pp.117-124
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• 2011

Many studies of the phytoplankton community structure have been conducted using the CHEMTAX program on the basis of the photosynthetic pigment concentrations measured by a HPLC (High-Performance Liquid Chromatography) technique. The CHEMTAX program determines the contribution of each phytoplankton class to total phytoplankton biomass (chlorophyll a) based on the ratios of marker pigment to chlorophyll a of phytoplankton group. In this study, the marker pigment/chlorophyll a ratios were investigated in phytoplankton species isolated from marine waters around the Korean peninsula. These results were used as the input pigment ratios of the CHEMTAX program to investigate phytoplankton community structure in Korean coastal waters (Yeoja and Gamak Bay). There were significant differences in the ratios of marker pigment to chlorophyll a among the different species within the same algal class. There was a significant difference between the values of our ratios and the previously used ratios in other regions of the world. When phytoplankton community composition was calculated using our initial ratios in Yeoja and Gamak Bay, our results were significantly different from the results calculated on the basis of initial ratios of marker pigment in phytoplankton suggested in other marine waters. The estimates of the contributions of the major algal groups (bacillariophyceae and dinophytes) to total chlorophyll a varied within 5% depending on the initial ratios chosen. The variations of estimates for the pico- and nanoplankton (cyanophytes and prasinophytes), which have relatively low contributions to total chlorophyll a, were higher than those for major algal group. Although the HPLC-pigment measurements combined with CHEMTAX analysis are useful for identifying and qualifying phytoplankton community structure, further researches for the pigment ratios of the dominant phytoplankton species presenting in a given area are also needed.

• The Journal of Engineering Geology
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• v.16 no.1 s.47
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• pp.69-83
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• 2006

This study aims to evaluate a complex groundwater flow system around the underground oil storage caverns using the concept of hydraulic compartment. For the hydrogeological analysis, the hydraulic testing data, the evolution of groundwater levels in 28 surface monitoring boreholes and pressure variation of 95 horizontal and 63 vertical water curtain holes in the caverns were utilized. At the cavern level, the Hydraulic Conductor Domains(fracture zones) are characterized one local major fracture zone(NE-1)and two local fracture zones between the FZ-1 and FZ-2 fracture zones. The Hydraulic Rock Domain(rock mass) is divided into four compartments by the above local fracture zones. Two Hydraulic Rock Domains(A, B) around the FZ-2 zone have a relatively high initial groundwater pressures up to $15kg/cm^2$ and the differences between the upper and lower groundwater levels, measured from the monitoring holes equipped with double completion, are in the range of 10 and 40 m throughout the construction stage, indicating relatively good hydraulic connection between the near surface and bedrock groundwater systems. On the other hand, two Hydraulic Rock Domains(C, D) adjacent to the FZ-1, the groundwater levels in the upper and lower zones are shown a great difference in the maximum of 120 m and the high water levels in the upper groundwater system were not varied during the construction stage. This might be resulted from the very low hydraulic conductivity$(7.2X10^{-10}m/sec)$ in the zone, six times lower than that of Domain C, D. Groundwater recharge rates obtained from the numerical modeling are 2% of the annual mean precipitation(1,356mm/year) for 20 years.

• Journal of Korean Home Economics Education Association
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• v.33 no.1
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• pp.1-16
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• 2021

The purpose of this study was to investigate the needs of middle school students for the practical reasoning in a distance learning environment, to verify the needs differences based on the learner's personal characteristics, student-teacher interaction, and student-student interaction, and to investigate the relationships among student-teacher interaction, voluntary participation of students, and the students' perception of the extent to which practical reasoning is implemented in distance learning. For this purpose, 1,842 middle school students from seven schools in Gyeonggi, Daejeon, Chungbuk, and Sejong areas were surveyed online to investigate the importance of the practical reasoning questions and the how much practical reasoning is implemented in current distance learning. Among them, 1,095 responses were used for final analysis and descriptive statistics, independent sample t-test, one-way ANOVA, and path analysis were conducted. As a result of the study, first, middle school students acknowledged that the practical reasoning was important with the importance average 3.76. Based on the locus for focus model, the priorities of the needs in home economics class were examined, and the values and importance of the problem, and the ramification of the solution were considered to be of high priority. Second, characteristics of middle school students, student-teacher interaction and student-student interaction were found to have positive influence on needs for practical reasoning, while no difference were found by gender or voluntary participation in distance learning. Third, the voluntary participation of students and the student-teacher interaction in distance learning had a positive (+) significant effect on perceived implementation of practical reasoning, yet negative (-) significant effect on needs for practical reasoning.

• Journal of the Korean Society of Earth Science Education
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• v.17 no.2
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• pp.123-136
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• 2024

This study examines the performance expectations (PEs) and clarification statements of each PE in the 2022 revised national science and mathematics education standards from a data visualization competency perspective. First, the authors intensively reviewed data visualization literature to define key competencies and developed a framework comprising four main categories: collection and pre-processing skills, technical skills, thinking skills, and interaction skills. Based on the framework, the authors extracted a total of 191 mathematics and 230 science PEs from the 2022 revised science and mathematics education standards (Ministry of Education Ordinance No. 2022-33, Volumes 8 and 9) as the main data set. The analysis process consisted of three steps: first, the authors organized the data (421 PEs) by the four categories of the framework and four grade levels (3-4th, 5-6th, 7-9th, and 10th grade); second, the numbers of PEs in each grade level were standardized by the accomplishing period (1-3 years) of each PE depending on the grade level; lastly, the data set was represented by heatmaps to visualize the relationship between the four categories of visualization competency and four grade levels, and the differences between the competency categories and grade levels were quantitatively analyzed using the Mann-Whitney U test and independent sample Kruskal-Wallis tests. The analysis results revealed that in mathematics, there was no significant difference between the number of PEs by grade. However, on average, the number of PEs categorized in 'thinking skills' was significantly lower than those in the technical skills (p = .002) and interaction skills categories (p = .001). In science, it was observed that as grade level increased, PEs also increased (pairwise comparison: Grades 5-6 vs. 7-9, p = .001; Grades 5-6 vs. Grade 10, p = .029; Grades 3-4 vs. 7-9, p = .022). Particularly, the frequency of PEs in 'thinking skills' was significantly lower than in the other skills (pairwise comparison: technical skills p = .024; collection and pre-processing skills p = .012; interaction skills p = .010). Based on the results, two implications for revising national science and mathematics standards and teacher education were suggested.