• Korean Journal of Cognitive Science
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• v.28 no.3
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• pp.149-171
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• 2017

In this research, based on the fact that spatial ability is important for the achievement in the STEM fields, and technological innovation, Purdue Spatial Visualization Test-Rotation has been used to investigate engineering freshmen's spatial ability and gender differences. Students who have taken advanced mathematics courses in high school(those who have taken type B math test in Korean SAT test) and students with general math courses(those who have taken type A in Korean SAT-Math test) are included in this study to find out the relationship between mathematics achievement and spatial ability. Finding out the strategies taken by students was another aim of this study. This strategic differences between high achievers and lower achievers, male and female students were analyzed from students' self report. Spatial ability test score was highest in the SAT-Math type B male students, decreased in the order of type A male students, type B female students, and lastly type A female students. There was no substantial difference between second and third groups. In each group, male students' average score was 8~10% higher than female students, which affirms 2015's results. The correlation between spatial ability and mathematics achievement was negligible in each group, but male students' math score and spatial ability score were higher than that of female students. This can be interpreted that there is some correlation between these two. Strategic choices can vary in the continuous spectrum with analytic method and holistic method at both ends. From students' self report, using Mann-Witney test, it turned out that there exists strategic differences between male and female students. Male students have a tendency to use holistic strategy more often than female students. I also found that the strategy choice did not vary greatly among all score groups. For the perfect score groups, both female and male students used holistic strategy most frequently. For low achieving groups, there is an evidence that these students overuse one method compared to average or high achieving groups, which turned out to be less effective. Based on these, I suggest that low achieving students need to have more chances to adopt efficient strategies and to practice challenging problems to improve their spatial abilities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.602-612
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• 2010

This study was conducted to investigate the state of hygiene education aimed for by bakers, and the evaluations of the importance and the performance concerning sanitary characteristics by the bakers. The questionnaires were administered to 186 bakers in Busan and the data evaluated by 5 scales method of Likert were statistically analyzed. 20.4% of bakers have not received hygiene education. Only 32.8% of bakers have experienced hygiene education regularly. The more the bakers were educated, the more they practiced the contents of hygiene education. The major reason of education unfulfilment was due to insufficient equipments and facilities. The scores of the hygienic performance of educated bakers were significantly (p<0.05) higher than those of uneducated bakers in food sanitation, especially for sanitary characteristics on inspection, pre-preparation and distribution. The mean scores of the importance and the performance evaluated by bakers were 4.05/5.00 and 3.76/5.00, respectively. The bakers assessed the highest scores on the importance and the performance of personal hygiene. The gap score was -0.30 between the importance and the performance for sanitary characteristics. The baker recognized that sanitary management was not performed as much as they recognized its importance. The importance and the performance grid of bakers revealed that the items of checking the certification for the origin of new food ingredient, inspecting deliveries as quickly as possible, separation between preparing and breading time, thawing frozen food under running tap water/in refrigerator, separating disposal gloves and utensils by the purpose, putting products in cleaned and sterilized utensils, letting consumes know the expiration date of products, preventing a rubber hose from being left on the kitchen floor, checking insect nets frequently and so on showed lower scores compared to the mean scores of the importance and the performance. The levels of the hygienic performance by bakers were positively correlated (p<0.01) with the recognitions of the importance on sanitary characteristics. These results might provide basic data for hygienic training and play a role on the improvement of the sanitary management in bakery.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.11-17
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• 2013

Purpose: The use of SUV which should be normalized by lean body mass (LBM) is recommended for PET response criteria in solid tumors. LBM which was determined by whole body CT was used for SUV normalization (SUL) in this study. The purpose of the present study was to assess interobserver and intraobserver reproducibility of SUL measurements in reference organs. Materials and Methods: F-18 FDG PET/CT was conducted on 52 subjects and LBMs were directly determine by whole body CT for normalization of SUV. The 3 cm diameter spherical VOI, $1\times2$ cm cylindrical VOI, 2 cm diameter spherical VOI were placed in the liver, descending aorta and spleen, respectively. Experienced two observers measured SULmax and SULmean in each organ. Repeated measurements were conducted two weeks apart by observer 1 blind to previous results. Similarly, measurements were conducted on the same patients by observer 2. For assessing reproducibility(or repeatability), the paired t-test, Pearson's correlation coefficients (CC), and technical error of measurement (TEM) were calculated. Results: For interobserver reproducibility in liver SULmax and SULmean, no significant differences were found between observers(paired t-test, P=0.536, 0.293, respectively). CC and TEM for liver SULmean were 0.909 (P=0.000) and 0.067 SUL unit, respectively. Corresponding figures for liver SULmax were 0.882 (P=0.000) and 0.117 SUL unit, respectively. For intraobserver reproducibility in liver SULmax and SULmean, no significant differences were observed within observer1 (paired t-test, P=0.374, 0.268, respectively). CC and TEM for liver SULmean were 0.924 (P=0.000) and 0.061 SUL, respectively. Corresponding figures for liver SULmax were 0.908 (P=0.000) and 0.104 SUL, respectively. Similarly, no significant differences were found in SULmax and SULmean of the spleen and aorta between observers. Conclusion: The current study demonstrated that both SULmean and SULmax measurements in normal reference organs are highly reproducible. Reproducibility of SULmean in reference organs were slightly better than SULmax. Interobsever technical error of measurement was less than 0.10 SUL unit for liver SULmean, and 0.12 SUL unit for liver SULmax. Intraobsever technical error of measurement was less than 0.07 SUL unit for liver SULmean, and 0.11 SUL unit for liver SULmax.

• Food Engineering Progress
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• v.23 no.1
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• pp.7-15
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• 2019

The impregnation of solid foods into the surrounding hypotonic or hypertonic solution was explored as a method to infuse NaCl in pork loin cube without altering its matrix. Mass transfer kinetics using a diffusive model as the mathematical model for moisture gain/loss and salt gain and the resulting textural properties were studied for the surrounding solutions of NaCl 2.5, 5.0, 10.0 and 15% (w/w). It was possible to access the effects of brine concentration on the direction of the resulting water flow, quantify water and salt transfer, and confirm tenderization effect by salt infusion. For brine concentrations up to 10% it was verified that meat samples gained water, while for processes with 15% concentration, pork loin cubes lost water. The effective diffusion coefficients of salt ranged from 2.43×10^-9 to 3.53×10^-9 m²/s, while for the values of water ranged from 1.22×10^-9 to 1.88×10^-9 m²/s. The diffusive model was able to represent well salt gain rates using a single parameter, i.e. an effective diffusion coefficient of salt through the meat. However, it was not possible to find a characteristic effective diffusion coefficient for water transfer. Within the range of experimental conditions studied, salt-impregnated samples by 5% (w/w) brine were shown with minimum hardness, chewiness and shear force.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.64-75
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• 2017

The role of a track subgrade is to provide bearing capacity and distribute load transferred to lower foundation soils. Track subgrade soils are usually compacted by heavy mechanical machines in the field, such that sometimes they are attributed to progressive residual settlement during the service after construction completion of the railway track. The progressive residual settlement generated in the upper part of a track subgrade is mostly non-recoverable plastic deformation, which causes unstable conditions such as track irregularity. Nonetheless, up to now no design code for allowable residual settlement of subgrade in a railway trackbed has been proposed based on mechanical testing, such as repetitive triaxial testing. At this time, to check the DOC or stiffness of the soil, field test criteria for compacted track subgrade are composed of data from RPBT and field compaction testing. However, the field test criteria do not provide critical design values obtained from mechanical test results that can offer correct information about allowable permanent deformation. In this study, a test procedure is proposed for permanent deformation of compacted subgrade soil that is used usually in railway trackbed in the laboratory using repetitive triaxial testing. To develop the test procedure, an FEA was performed to obtain the shear stress ratio (${\tau}/{\tau}_f$) and the confining stress (${\sigma}_3$) on the top of the subgrade. Comprehensive repetitive triaxial tests were performed using the proposed test procedure on several field subgrade soils obtained in construction sites of railway trackbeds. A permanent deformation model was proposed using the test results for the railway track.

• Analytical Science and Technology
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• v.24 no.6
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• pp.503-509
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• 2011

Specific surface area is becoming a very important factor when newly developed advanced nano-materials are evaluated. But there have been many differences in results when measuring specific surface areas, depending on the measuring equipments and analysis method. To verify the reliability of the specific surface area measurement device supplied within the country, Round Robin Test (RRT) has been done at 21 affiliated research institutes. As a result, it was found that several institute had problems in measuring of gas adsorption amount in measuring equipment, and this proved the need for certified reference material (CRM). Furthermore, it was also found that the results from BET analysis is easily swayed by the analyst's subjectivism, and the calculated results may differ up to 16% in case of CRM I depending on the selection range of BET analysis. So this showed that a standard guideline for BET constant C value and fitting correlation coefficient R is needed, to properly select range in BET analysis. The experience in RRT, distribution of CRM, and standardized procedure would result in improved reliability in industrial processes, and thus, would contribute to the quality management, the productivity improvement, the safety evaluation, and the new material development.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.16 no.2
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• pp.33-56
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• 2005

The purpose of this study is to understand the critical role of customers' perceived service quality. in relationship marketing. This paper examined the relationships of service quality with customer satisfaction, and investigated the effects of trust and commitment. Data were collected from 242 people at hotel located in Taegu city. LISREL provided satisfactory model-fits in measurement model and structural equation model. The empirical results indicated that first, service quality takes strong effect on customer satisfaction and trust but not on commitment. Second, trust and commitment are importantly influenced by customer satisfaction. Third, service quality was found to indirectly contribute to trust and commitment. Finally, customer satisfaction is effective mediators linking service quality to trust and commitment. The effects of these variables on trust and commitment, which are based on social exchange theory, were empirically confirmed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.3
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• pp.237-245
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• 2004

In designing a tunnel, RMR has been widely used to classify rock mass and to decide the support pattern according to the class of rock mass. However, this RMS system can't help relying on the empirical judgment of engineers who use variables which can be obtained only through consideration of the site conditions. In actuality, it is impossible to consider all the rating factors of RMS when using RMR system at the stage of designing. Therefore, in order to confirm possibility of RMR by use of only the quantitative factors for designing, this paper has done discriminant analysis. Rock strength or RQD has high coefficient of correlation with RMR value, and in consideration of the existing standards for rock mass classification, rock intensity and RQD are important factors for classification of rock mass. Through rock mass classification by the existing RMR system and rock mass classification by the discriminant analysis which has considered two variables only, the discriminant analysis using the rock intensity as an independent variable has shown 74.8% accuracy while the discriminant analysis using RQD as an independent variable has shown 74.3% accuracy. In case of the discriminant analysis which has considered both rock intensity and RQD, it has shown 82.5% accuracy. The existing cases have shown 40.3% accuracy at the stage of designing in which all the RMR factors are considered. It means that at the stage of designing, RMR system can work only with the rock intensity and RQD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.379-387
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• 2020

This exploratory study evaluated various factors influencing the level of nursing self-confidence in the performance of core nursing skills among nursing students. This study surveyed 131 senior nursing students in U city with a structured self-report questionnaire analyzed by SPSS 23.0 software. The average perception scores for importance, problem-solving process, and self-confidence in the performance of core nursing skills were 4.73, 3.57, and 3.90, respectively. The most significant factors affecting self-confidence in the performance of core nursing skills included problem-solving process (β=.33, p=.001) and nursing satisfaction (β=.27, p=.019). These variables explained 15% of the total variance in self-confidence in the performance of core nursing skills. Based on the results of this study, it is necessary to perform research in order to improve the self-confidence of performing core basic nursing skills among nursing students, and the department of nursing defines students' problems by suggesting changes in the practice environment and various nursing situations to improve interpersonal skills. Therefore, it is necessary to develop a curriculum that can be solved and a program to increase nursing satisfaction.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.171-187
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• 2017

Thisstudy presentsthe method for deriving surface visibility from satellite retrieved AOD. To do thisthe height of aerosol distribution isrequired. This distribution would be in thisstudy represented by the two heights; if there is a discrete atmospheric layer, which is physically separated from the above layer, the upper height of the layer is assumed as Aerosol Layer Height(ALH). In this case there is clear minimum in the Relative Humanity vertical distribution. Otherwise PBLH(Planetary Boundary Layer Height) is used. These heights are obtained from the forecast data of Regional Data Assimilation and Prediction System(RDAPS). The surface visibility is estimated from MODIS AOD and ALH/PBLH, using Koschmieder's Law for ALH and the empirical relations for PBLH. The estimated visibility are evaluated from the visibility measurements of 9 eve-measurement stations and 17 PWD22 stations for the spring of 2015 and 2016. Verification of the estimated visibility shows that there are considerable differencesin statistical verification value depending on stations, years, morning(Terra)/afternoon(Aqua). The better results are shown in the midwest part of korean peninsula for Terra of 2016. The results are summarized as; correlation coefficients of higher than 0.65, for low visibility RMSE of 3.62 km and ME of 2.29 km or less, POD of higher than 0.65 and FAR of 0.5 or less. Verification results were better with increase in the number of low-visibility data.