• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.783-787
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• 2008

IEEE 802.16/WiBro, one of the representative Broadband Wireless Access (BWA) systems, defines QoS negotiation between BS and SS and five service classes to guarantee QoS for flows. The five service classes are UGS, ertPS, rtPS, nrtPS, and BE, but the standard does not define how to provide services to flows according to the service classes. Existing research works have been studied about the scheduler architecture to effectively utilize the IEEE 802.16/WiBro systems. These works use the original packet scheduling algorithm for service classes. However, it is necessary to consider bandwidth allocation mechanisms in scheduling algorithms since bandwidth allocation mechanisms are different according to service classes. Especially, bandwidth allocation mechanisms should be considered for the scheduling of rtPS class since rtPS class uses the polling mechanism that takes time to allocate bandwidth and has the minimum latency constraint. Therefore, we propose two stage dropping scheme for rtPS class that is sensitive to latency, and thus it reduces the wasted resources and provides efficient service to rtPS class.

• Communications of Mathematical Education
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• v.34 no.1
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• pp.17-39
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• 2020

The purpose of this study is to analyze the mathematical beliefs of students and teachers by Latent Class Analysis(LCA). This study surveyed 60 teachers about beliefs of 'nature of mathematics', 'mathematic teaching', 'mathematical ability' and also asked 1850 students about beliefs of 'school mathematics', 'mathematic problem solving', 'mathematic learning' and 'mathematical self-concept'. Also, this study classified each student and teacher into a class that are in a similar response, analyzed the belief systems and built a profile of the classes. As a result, teachers were classified into three types of belief classes about 'nature of mathematics' and two types of belief classes about 'teaching mathematics' and 'mathematical ability' respectively. Also, students were classfied into three types of belief classes about 'self concept' and two types of classes about 'School Mathematics', 'Mathematics Problem Solving' and 'Mathematics Learning' respectively. This study classified the mathematics belief systems in which students were categorized into 9 categories and teachers into 7 categories by LCA. The belief categories analyzed through these inductive observations were found to have statistical validity. The latent class analysis(LCA) used in this study is a new way of inductively categorizing the mathematical beliefs of teachers and students. The belief analysis method(LCA) used in this study may be the basis for statistically analyzing the relationship between teachers' and students' beliefs.

• Survey Research
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• v.12 no.2
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• pp.113-144
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• 2011

The purposes of the present study were (1) to identify the latent classes depending on youth employees' trajectories in job satisfaction and turnover intention and (2) to test the effects of person-job fit(major fit, education level fit, skill level fit) on job satisfaction and turnover intention using Youth Panel 2001. In order to estimate latent classes of job satisfaction and turnover intention changes simultaneously and study probabilities linking latent class membership in trajectory across the two variables, we applied dual trajectory model, an extension of semi-parametric group-based approach, Results showed that four latent classes were identified for job satisfaction, which were defined, based on the trajectory patterns, as increasing group, decreasing group, medium-level group, and high-level group. And, three latent classes estimated for turnover intention were defined as low-level group, maintaining group, and rapidly decreasing group. To test the effects of person-job fit variables, we added the variables as time-dependant variables to the unconditional latent class model. The effect of education level fit and skill level fit were found significant in the groups which are low in job satisfaction and have high in turnover intention. Findings from this study suggest the need to consider trajectory heterogeneity in the study of youth employees' job satisfaction and turnover intention to capture the dynamic dimension of overlap between the two constructs.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.2
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• pp.179-198
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• 2023

The purpose of this study is to verify the role of teacher librarians by examining the cases of media and information literacy(MIL) classes in the joint curriculum of high school credit system research school. The classes were two 34th classes joint curriculum established by two teacher librarians at the high school credit system research school. Individual students set their own inquiry problems integrated with their careers or subjects, and teacher librarians guide the process of solving them based on the process of using MIL. The participants were 22 high school students in Daegu who filled out the questionnaire before and after completing the course. The effect of the classes was analyzed through a questionnaire consisting of 42 questions for the 3 factors of access, evaluation, and creation, which are the components of MIL announced by UNESCO. As a result, all 3 factors and 25 of the sub-42 survey items showed a statistically significant difference before and after class, It was investigated that literacy of students improved through MIL education of teacher librarians. Through this study, it will be possible to expand the awareness of the effect of the educational role of teacher librarians in the flow of future curriculum.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.565-574
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• 2018

The purpose of this study is to investigate the features of science classes of Science Core Schools (SCSs) perceived by students. 654 students from 14 SCSs were surveyed with two open-ended questions on the features of science classes. The students' responses were analyzed with NetMiner 4.5, in terms of the centrality (of betweenness and of degree) analysis and the community analysis. The results of the research are as follows: (1) the science classes of SCSs were perceived by students to be of the environment of free questioning, active participation and communication, caring teacher, more science experiments and advanced contents, and knowledge sharing; (2) science classes in SCSs were perceived to be different from those of ordinary high schools because SCSs provide more opportunities for science-related special courses (like project work, advanced science subjects), extra-curricular activities, inquiry and research activities, school supports, hard-working classroom environment, longer studying hours, R&E and club activities. The students' perceptions of SCS science classes appear to be in line with the characteristics of 'good' science lessons from previous studies. The SCS project itself and the features of SCS science classes would help us to see how we introduce educational innovations into actual schools.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.793-804
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• 2009

In this study, high school students' perceptions of chemically ill-defined ‘heavy metals’ were examined through questionnaires. Nineteen classes of 11th graders (N = 611) were divided into two groups according to completion of 'Chemistry I', which were 10 science-classes and 9 liberal art-classes and compared each other. Three terms of students' cognition and definition, impact on the formation of their cognition, and their chemical knowledge of 'heavy metals' were analyzed by SPSS. The findings revealed that most of students recognized ‘the heavy metal’ as the metal which causes to be accumulated on any living thing and is hazardous in human body regardless of different major between liberal art and science. Mass media and school instruction were found to be the greatest impact on the formation of these cognitions. Especially, school instruction had more effects on students majoring in science than students majoring in liberal art, which bring the result that students in science-classes have more misconception about the definition of 'heavy metals' with human toxicant regardless of metal species and its content in human body and physical density due to the ill-defined terminology of the textbook than students in liberal art-classes do. It is interesting that students in science-classes understood hazard and chemical structure of 'heavy metals' better, while students in liberal art-classes answered the question better about hazardous properties of heavy metals.

• Journal of the Korean Society of Food Culture
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• v.4 no.1
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• pp.71-82
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• 1989

While ruling Chosun, with a view to making Chosun the primary supplier of food, Japan made the peasantry of Chosun go to ruin by leaving land from them through land enterprises, and the projects of increasing rice production. At the same time, Japan formed the higher classes comprising pro-Japanese capitalists, landlords and intellectuals, and protected them in order to carry out her colonial policies. Naturally there came into being a great gulf between the minority of high society and the majority of the poor in Chosun. As there was a great difference in food life between the two, I'm going to examine the literature of those days to grasp exactly the condition of their food intake. As for the staple food, out of thirteen provinces in Chosun, 13% lived on only rice and 27% on other minor cereals with no rice. As for the subsidiary food, about thirty percents did not take any animal protein. The examination of intake of nutrition by classes shows that the higher and middle classes took the necessary amount of calorie and protein and that the component ratio of calorie was comparatively properly distributed. The lower classes are defined as those whose monthly income was less than 100 won and the peasantry in general. And again the peasantry are classified into three-high, middle and low-according to their farming conditions. The tenant farmers in Kyeongguido and the peasants of Darli community took enough amount of calorie and protein, but much smaller amount of animal protein. Fire-field farmers led not less miserable food intake than the extremely poor peasants. They seldom lived on rice. Potatoes, oats and millets were their staple food. Lastly, Engel's coefficient for the Tomack-min (the residents in mud huts) who were among the three extremely poor classes, was 73.3%, which was much higher than that of the lower classes in then Japan. Rationed rice and barley were their staple food but the rationed amount was not sufficient to satisfy needs of physical labor. In conclusion, during the period of Japanese ruling of Chosun, the minority of higher and middle classes in Chosun generally took sufficient amount of nutrient, while the status of food intake with poor peasants, fire-field farmers and Tomack-min was extremely miserable.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.60-85
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• 2014

The study is for tracing the mutational process, considering the transformational process of wooden chamber tombs in Gyoungju region during 2~6 century. In addition, class features and the meaning of tombs were studied. First of all, the wooden chamber tombs were classified into 10 different styles(1A~IVC), based on the filling materials, the ways of structure, and the structure of burial chamber. There were only one or two tombs that belongs to the highest classes 'Ga'~'Da' in each period, which has the numeral features. Furthermore, the styles of the central wooden chamber tombs according to the period and the region have distinctive features and have changed so far. It shows that there are the rank among the tombs in the regions. In other words, regarding the ranks of the class 'Ga'~'Cha', there were strict rules and the limitations on the size of the tombs and the number and the quality of the burial relics. It means that the inner-outer size or the structure of the tombs and the number, quality of the burial goods depended on the buried person's birth or social classes, or achievements. Based on Shila social classes, the class 'Ga' tombs were for the highest classes when considered the size, burial relics, and the quality. The class 'Na' and 'Da' tombs were for the higher classes, 'Ma' for middle classes, 'Ba', 'Sa' for lower classes. In addition, 'Ah', 'Ja' tombs were for higher commoner, 'Cha' for lower commoner. Thus, class 'Ga'~'Sa' is the leading class of Shila.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.321-328
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• 2023

This study is tried to to identify factors affecting academic achievement depending on the quality of class, learning immersion, level of academic achievement, and class type according to video production classes and real-time video classes in the on-contact learning situation due to the COVID-19 epidemic. The subjects of the study were 122 students enrolled in the nursing department at two universities. As a result of the study, the quality of the class was high in real-time video classes (t=-2.69, P=0.02), learning immersion was high in video production classes (t=1.14, P=0.28), and academic achievement was high in video production classes (t=4.24, P=0.01). Depending on the type of class, the effect on academic achievement is learning immersion in production video classes (β=.37, p<.001) has the most influence, and in real-time video classes, class quality (β=.29, p<.001) had the most influence on academic achievement. Based on the results of this study, it is suggested that it is necessary to develop a strategy for instructional design suitable for class types to improve academic achievement in an on-contact environment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.63-94
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• 2002

On the purpose to suggest an advanced scheme in assessing the domestic wheat quality, this paper reviewed the inspection systems of wheat in major wheat producing countries as well as the quality criteria which are being used in wheat grading and classification. Most wheat producing countries are adopting both classifications of class and grade to provide an objective evaluation and an official certification to their wheat. There are two main purposes in the wheat classification. The first objectives of classification is to match the wheat with market requirements to maximize market opportunities and returns to growers. The second is to ensure that payments to glowers aye made on the basis of the quality and condition of the grain delivered. Wheat classes has been assigned based on the combination of cultivation area, seed-coat color, kernel and varietal characteristics that are distinctive. Most reputable wheat marketers also employ a similar approach, whereby varieties of a particular type are grouped together, designed by seed coat colour, grain hardness, physical dough properties, and sometimes more precise specification such as starch quality, all of which are genetically inherited characteristics. This classification in simplistic terms is the categorization of a wheat variety into a commercial type or style of wheat that is recognizable for its end use capabilities. All varieties registered in a class are required to have a similar end-use performance that the shipment be consistent in processing quality, cargo to cargo and year to year, Grain inspectors have historically determined wheat classes according to visual kernel characteristics associated with traditional wheat varieties. As well, any new wheat variety must not conflict with the visual distinguishability rule that is used to separate wheats of different classes. Some varieties may possess characteristics of two or more classes. Therefore, knowledge of distinct varietal characteristics is necessary in making class determinations. The grading system sets maximum tolerance levels for a range of characteristics that ensure functionality and freedom from deleterious factors. Tests for the grading of wheat include such factors as plumpness, soundness, cleanliness, purity of type and general condition. Plumpness is measured by test weight. Soundness is indicated by the absence or presence of musty, sour or commercially objectionable foreign odors and by the percentage of damaged kernels that ave present in the wheat. Cleanliness is measured by determining the presence of foreign material after dockage has been removed. Purity of class is measured by classification of wheats in the test sample and by limitation for admixtures of different classes of wheat. Moisture does not influence the numerical grade. However, it is determined on all shipments and reported on the official certificate. U.S. wheat is divided into eight classes based on color, kernel Hardness and varietal characteristics. The classes are Durum, Hard Red Spring, Hard Red Winter, Soft Red Winter, Hard White, soft White, Unclassed and Mixed. Among them, Hard Red Spring wheat, Durum wheat, and Soft White wheat are further divided into three subclasses, respectively. Each class or subclass is divided into five U.S. numerical grades and U.S. Sample grade. Special grades are provided to emphasize special qualities or conditions affecting the value of wheat and are added to and made a part of the grade designation. Canadian wheat is also divided into fourteen classes based on cultivation area, color, kernel hardness and varietal characteristics. The classes have 2-5 numerical grades, a feed grade and sample grades depending on class and grading tolerance. The Canadian grading system is based mainly on visual evaluation, and it works based on the kernel visual distinguishability concept. The Australian wheat is classified based on geographical and quality differentiation. The wheat grown in Australia is predominantly white grained. There are commonly up to 20 different segregations of wheat in a given season. Each variety grown is assigned a category and a growing areas. The state governments in Australia, in cooperation with the Australian Wheat Board(AWB), issue receival standards and dockage schedules annually that list grade specifications and tolerances for Australian wheat. AWB is managing "Golden Rewards" which is designed to provide pricing accuracy and market signals for Australia's grain growers. Continuous payment scales for protein content from 6 to 16% and screenings levels from 0 to 10% based on varietal classification are presented by the Golden Rewards, and the active payment scales and prices can change with market movements.movements.