• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.133-138
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• 2002

In this paper, we model a two-server queueing system with priority, to which we put a restriction of the number of servers for each customer class. A group of customers is divided into two different classes. The class 1 customers has non -preemptive priority over class 2 customers. We use the method of PGF depending on the state of server We find the PGF of the number of customers in queue, server utilization, mean queue length and mean waiting time for each class of customers.

• Asia pacific journal of information systems
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• 제21권2호
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• pp.43-58
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• 2011

Support vector machines (SVMs), a machine learning technique, has been applied to not only binary classification problems such as bankruptcy prediction but also multi-class problems such as corporate credit ratings. However, in general, the performance of SVMs can be easily worse than the best alternative model to SVMs according to the selection of predictors, even though SVMs has the distinguishing feature of successfully classifying and predicting in a lot of dichotomous or multi-class problems. For overcoming the weakness of SVMs, this study has proposed an approach for selecting features for multi-class SVMs that utilize the impurity measures of classification trees. For the selection of the input features, we employed the C4.5 and CART algorithms, including the stepwise method of discriminant analysis, which is a well-known method for selecting features. We have built a multi-class SVMs model for credit rating using the above method and presented experimental results with data regarding S&P 500 companies.

• Journal of Engineering Education Research
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• 제20권6호
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• pp.3-11
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• 2017

The purpose of this study is to investigate the variables that learners should consider for learning persistence when applying blended learning to mathematics class which is a basic curriculum of engineering college. For this purpose, this study compared the basic mathematics class with the blended learning and the class without it. In addition, this study analyzed the influence of the learning outcomes of the blended learning on the willingness to learning persistence by using the self-efficacy and self-regulated learning variables that can predict it. As a result, it was found that the blended learning applied mathematics class of K university which is the subject of analysis in this study has higher self - efficacy, self - regulated learning, and learning persistence intention than general classroom. Finally, the results of this study are meaningful to provide the points to be considered for improving the learning performance when applying the blended learning to the subject class in the future.

• Korean Security Journal
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• 제21호
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• pp.19-33
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• 2009

This study attempted to investigate the effect of class satisfaction of the students majoring in the studies of security services on the efficacy of career decision. To do this, I chose 430 security services of the students majoring by the systematic stratified cluster random sampling as the subject of study. All data were analyzed the causal relationship of the collected equation. In order to do a data analysis used descriptive statistics analysis, t-test, one-way ANOVA and multiple regression analysis of SPSS. As a result, the following conclusion was drawn: First, it was found that there was not a statistically significant(learning factor, interpersonal relation, aptitude factor) difference in their major class satisfaction and career decision efficacy(goal choice, future plan, working information) according to gender. Second, it was found that there was a statistically signifiant difference in such factors as learning, interpersonal relations and aptitude, in relation to the difference in subfactor such as major class satisfaction and career decision efficacy. Third, it was found that the learning, aptitude and career factors of major class satisfaction had a statistically significant effect on the future plan. Fourth, it was found that he learning and career factors of major class satisfaction had a statistically significant effect on the resolution of the goal. Fifth, it was found that the aptitude and career factors of major class satisfaction had a statistically significant effect on job information. Sixth, it was found that the career factors of major class satisfaction had a statistically significant effect on the problem-solution. Therefore, we must first give priority to improve the class satisfaction. By doing this, we can raise the efficacy level of career decision.

• Environmental and Resource Economics Review
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• 제19권4호
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• pp.853-874
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• 2010

This study examines the acceptability of nuclear facilities using the latent class analysis. Even though, nuclear power is useful in terms of economic and energy security aspects, it is very difficult to expand the existing nuclear power plants or build a new one. Many studies analysed the cause of unacceptability of nuclear facilities but it has not been focused how large portion of people are divided pro and con. It is very important to know the distribution of people by the attitude toward nuclear facilities in order to meet the long term National Energy Plan. Through the latent class analysis with 1,025 respondents, people are classified into three groups(favor-class, support-class, opposition-class). The favor-class is the largest group which has moderate good attitudes toward the nuclear facilities in terms of economy, cleanness. and necessity but concerns a little about safety. The second largest group is the support-class which comprises 1/4 portion of people. The people in the class show the aggressive support for the nuclear facilities. 15% of the respondents belong to the opposition-class which show the negative attitudes to expansion of neclear facilities. In order to increase the acceptability of nuclear faculties, the most urgent work for the government to do is to less people's concern about nuclear safety.

• Journal of the Korean Chemical Society
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• 제66권3호
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• pp.218-227
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• 2022

The purpose of this study is to analyze the opinions of students by using the text mining to the good points and improvements among the descriptive course evaluation written by the students who participated in the university chemistry laboratory class, and to derive the improvement for the class. We analyzed the frequency of occurrence, co-occurrence and network of key words. As a result of the study, in the network of good points in the class, the most frequent mentions were made between class and professor, along with explanation, understanding, student, passion, fun, TA, experiment, help, etc. In the network of improvements in the class, the most frequent mentions were made between class and student, along with professor, content, explanation, exam, wish, experiment, understanding, difficult, thought, problem, etc. In other words, the students suggested the opinion that the contents of the class were well understood and that they felt fun and satisfied with the experimental process due to 'easy and detailed explanation' and 'TA's assistance' as good points of the class. On the other hand, the students suggested the negative opinions that the understanding and concentration in the class was decreased due to 'difficulty of content and exam', 'excessive assignments', and 'class environment' as improvements of the class.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• 제14권2호
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• pp.69-76
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• 2018

The paper presents preliminary investigation results for the effect of the baseline correction in the acceleration excitation method on finite element seismic analysis results (such as accumulated equivalent plastic strain, equivalent plastic strain considering cyclic plasticity, von Mises effective stress, etc) of nuclear safety Class I components. For investigation, finite element elastic-plastic time-history seismic analysis is performed for a surge line including a pressurizer lower head, a pressurizer surge nozzle, a surge piping, and a hot leg surge nozzle using the Chaboche hardening model. Analysis is performed for various seismic loading methods such as acceleration excitation methods with and without the baseline correction, and a displacement excitation method. Comparing finite element analysis results, the effect of the baseline correction is investigated. As a result of the investigation, it is identified that finite element analysis results using the three methods do not show significant difference.

• The korean journal of orthodontics
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• 제48권6호
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• pp.349-356
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• 2018

Objective: This study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images. Methods: CBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > $38.0^{\circ}$), normal ($30.0^{\circ}$ < SN-MP < $37.0^{\circ}$), and low (SN-MP < $28.0^{\circ}$) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance. Results: Buccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness. Conclusions: Skeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.

• Korean Journal of Microbiology
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• 제40권2호
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• pp.178-182
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• 2004

In the vegetative hyphae of Aspergillus nidulans, a zymogenic form of the class I chitin synthase activity was successfully measured by the assay condition for Saccharomyces cerevisiae class I chitin synthase, Chsl. The class I chitin synthase activity of the A. nidulans chsC wild type strain was increased about six-fold by trypsin-pretreatment, but that of the chsC disruption strain revealed no increase. Interestingly enough, level of the class I chitin synthase activity of the chsC disruption strain was almost the same as that of the chsC wild type without trypsin-pretreatment. These results indicated that the A. nidulans ChsC activity could be measured by account-ing the class I chitin synthase activity without the trypsin-pretreatment as an internal control. Consistence to the expression pattern of the chsC revealed by northern blot analysis, the activity of ChsC was increased upon reaching the culture time for acquiring developmental competence. Our results shown here also supported the previous report suggesting the possible involvement of ChsC in vegetative hyphal growth of A. nidulans.

• Journal of Fisheries and Marine Sciences Education
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• 제25권4호
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• pp.781-800
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• 2013

The purpose of this study was to investigate perception of primary school teachers about operation of after-school computer class. Research questions were set up as follows: First, what type is preferred on the operation type for after-school computer class? Second, what is the perception about the adequacy of contents for after-school computer class? Third, what is the perception about instructors' expertise? Fourth, what is the perception about the effects of after-school computer class? Finally, what is the perception about facilities/ equipment and evaluation system of after-school computer class? To figure out these questions, this study conducted literature review and questionnaire survey. The results of this study are as follows: First, approximately 82% of respondents preferred to have after-school computer class operated by outsourced agency. Second, overall, the perceptions about the operation of after-school computer class were positive: The adequacy of contents, instructors' expertise, the effects, facilities/ equipment and evaluation system are seen as mostly positive. Third, its differences between school self-operated computer class and private sector computer class were insignificant. Fourth, its differences among various sizes of the school were significant. The implementaion of after-school computer class was considered as more positive in small schools. Finally, researchers suggested that it was necessary to develop an plan considering school sizes for more efficient implementation of after-school computer class.