• Journal of Ship and Ocean Technology
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• v.9 no.2
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• pp.29-36
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• 2005

A hull form of Baltic ice class IA Aframax tanker has been developed taking into consideration of powering performance in brash ice channels based on IA class rules. Speed performance of the ship hull form in normal seagoing has been validated through model tests in a towing tank. The hull form design developed in this work has demonstrated good speed performance in normal seagoing although the ship design is entitled to ice class IA.

• Journal of Korean Elementary Science Education
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• v.29 no.1
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• pp.1-12
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• 2010

The purpose of this study is to analyze elementary school students' class contents and activities between the invention class for the gifted under the local education office by the 'Gifted Education Promotion Act' and that under the invention classroom by the 'Invention Promotion Act'. For this study, the survey was conducted to 1,788 elementary school students who attended the invention class for the gifted both under the local education office and under the invention classroom. The analysis of the survey showed that the students of the invention class for the gifted under the local education office had higher motivation and participation rate in class, higher interest in invention, and stronger significantly in a future oriented will than those under the invention classroom. The parents of the invention class for the gifted under the local education office showed more enthusiastic attitude to support their students, and had significantly stronger recognition that the participation of the students in the invention education for the gifted helped enter an advanced school than those under the invention classroom. However, the class contents of the invention class for the gifted under the local education office such as 'understanding the influence of the invention history and products on society', 'scientific inquiry skills for problem solving', 'technological and engineering abilities for creating an invention', 'developing knowledge and abilities about business and management by using a new invention' were not different from those under the invention classroom. In addition, discussion and presentation were not active in the class activities of the invention class for the gifted under the local education office. Therefore, the researchers should compensate and develop a program which can apply strategically differentiated class contents and class activities to the students who participate in the invention class for the gifted under the local education office by the 'Gifted Education Promotion Act'.

• Journal of the Korean Mathematical Society
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• v.56 no.4
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• pp.869-915
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• 2019

Let H be a Krull monoid with class group G such that every class contains a prime divisor. Then every nonunit $a{\in}H$ can be written as a finite product of irreducible elements. If $a=u_1{\cdot}\;{\ldots}\;{\cdot}u_k$ with irreducibles $u_1,{\ldots},u_k{\in}H$, then k is called the length of the factorization and the set L(a) of all possible k is the set of lengths of a. It is well-known that the system ${\mathcal{L}}(H)=\{{\mathcal{L}}(a){\mid}a{\in}H\}$ depends only on the class group G. We study the inverse question asking whether the system ${\mathcal{L}}(H)$ is characteristic for the class group. Let H' be a further Krull monoid with class group G' such that every class contains a prime divisor and suppose that ${\mathcal{L}}(H)={\mathcal{L}}(H^{\prime})$. We show that, if one of the groups G and G' is finite and has rank at most two, then G and G' are isomorphic (apart from two well-known exceptions).

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.4
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• pp.12-22
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• 1999

Operation of an electromagnetic shaker system using a Class-D amplifier may cause unacceptable electromagnetic interference to another electronic system, requiring the user to take whatever steps are necessary to correct the interference. A differential amplifier in a Class-D amplifier is used to decrease the effect of a common-mode noise voltage in a shaker system. To prevent a ground loop, a transformer is inserted in another shaker system. These methods show reduction of the unwanted vibration which has occurred before. A transformer in a charge amplifier was used to prevent a ground loop in a shaker system using a Class-AB amplifier a few years ago, but it was susceptible of noise in a shaker system using a Class-D amplifier. Hence we corrected a ground loop between a charge amplifier and a vibration control/analysis system without a transformer. The usefulness of this approach is illustrated by the results of experiments.

• Journal of Korean society of Dental Hygiene
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• v.20 no.1
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• pp.63-71
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• 2020

Objectives: This study provides basic data for developing practical teaching methods enabling efficient execution of the dental hygiene care process. Methods: A total of 197 dental hygiene students experienced in dental hygiene care process in Gwangju and Jeonnam were surveyed from June 1 to August 30, 2019 to study their class flow, professors-student relationships, and class satisfaction level. Post survey, statistical analysis was performed using frequency analysis, independent t-test, Pearson's correlation analysis, and multiple regression analysis. Results: 1. Class fl ow was high in three lecturers (3.56), four hours per week (3.39), and four hours per week (3.94). Class satisfaction was high in three lecturers (3.99) and four hours per week (3.90) (p<0.05). 2. There was a positive correlation between class flow and professor-student relationship (r=0.519), class fl ow and class satisfaction (r=0.566), and professor-student relationship and class satisfaction (r=0.838) (p<0.01). 3. The factors influencing class fl ow were the number of lecturers (β=0.442), class hours per week (β=-0.397), and class satisfaction (β=0.385). Conclusions: Apart from finding ways to improve class satisfaction for class flow in the dental hygiene care process, efforts are required to increase the number of lecturers and class hours per week for efficient class management. Further research is needed to develop practical teaching methods.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.376-387
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• 2017

The creative class is the class of workers whose job is to create meaningful new forms. Recently, much attention has been focused on the role of the creative class in regional development. Many policy makers have invested to amenities to attract more creative class into their cities or regions for regional economic growth. However, there are only a few studies about the migration of the creative class in Korea. The purpose of this study is to make an analysis of the movement of the creative class by using the 17th Korean Labor & Income Panel Study. According to empirical results, the creative class are more likely to move than the non-creative class. The characteristic of creative class who moved is related to married man aged 20s and 30s without own house. Also, there is the difference between determinants of migration of the creative class and the non-creative class. It was founded that the most important determinants of migration of the creative class are housing related reasons such as home ownership and job reasons. Relationship, convenient facilities are not important factors when the creative class make a decision to move.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.6
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• pp.49-56
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• 2013

This study investigated middle school students' perceptions of an optimum class size as well as the relationships between a class size and various aspects of students' lives at school. Data were gathered from 858 students from 8 classes (grade 1 and 2) at 4 middle schools located in Busan by administering survey questionnaires. The average class sizes to which each participating students belonged were 17.88, 30.0, 31.88, 28.0 respectively. A series of comparative analyses were carried out, revealing that the majority of the participating students perceived 25-30 as an optimum size for one class. Also, students in a relatively smaller class tended to show higher levels of satisfaction with school lives and with school and classroom facilities, more positive attitudes towards classroom atmosphere, and greater needs for peer interaction than did their counterparts. Furthermore, it was found out that the actual class size had to do with the students' perceptions of the relationships between school facilities and their levels of stress and pleasure at school. These findings were discussed in order to provide educators, architects, and policy makers with practical implications for bringing about a better school environment that is conducive to learning and living for middle school students.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.215-221
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• 2023

If the C++ programming class, an object-oriented language capable of modeling similar to the real world, is developed as a curriculum that introduces the flipped learning model, students' active problem-solving skills can be cultivated. In this subject development case, it is significant that the flipped learning technique was applied to the programming class and was effective in improving students' active problem-solving skills. First, the lectures in the 4th session were divided into Pre-Class, In-Class, and Post-Class, and the class was conducted in a way that suggested class goals suitable for the subject and formed a team to discuss. At the end of the lecture, a follow-up survey was conducted to check whether the learners learned effectively.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.157-160
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• 2008

The recent successes of systems like Google, Wikipedia and InnoCentive suggest that the time is now ripe for more such systems. Thus, we want to explore these systems and exploit them from a viewpoint of social psychology prior to technological progress. First of all, we examine the difference between 'wisdom of crowds' and 'crowd psychology'. There are two classes, which are for senior management major students. Conditions of two are same, except a class time. Forty five students in one class are tested for this experiment. They form a group with five people and are divided into 9 groups. In a case of a morning class, peer-to-peer evaluations are given to individuals in a class when a group presentation for a final project is given. On the other hand, in a case of afternoon class, peer-to-peer evaluations are given to each group in a class. The result is quite fruitful. The first is that an expert's evaluation for a project agrees with students, who are beginners in this field in the degree of more than 95%. However, in the case of afternoon class, students' group evaluation turns out to agree with an expert's one less than 53%. Morning class experiment result proves the truth of collective intelligence again. It tunrs out independent and confidential opinions are more cost effective and give right answers to questions than group opinions.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.216-224
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• 2013

The within-class variance of Otsu's method is moderate but improper in expressing class statistical distributions. Otsu's method uses a variance to represent the distribution of each class. The variance utilizes a distance square from the mean to a data. This process is not proper in denoting a real class statistical distribution because of the distance square. In this paper, to express more exact class statistical distributions, the within-class standard deviation as a criterion for threshold selection is proposed and then the optimal threshold is determined by minimizing it. In order to have validity, it is shown through the experimental results that the proposed method was more superior to the counterparts.