• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.125-133
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• 2008

In this paper, we propose active queue management mechanism (Active-WRED) to guarantee quality of the high priority service class in multi-class traffic service environment. In congestion situation, this mechanism increases drop probability of low priority traffic and reduces the drop probability of the high priority traffic, therefore it can improve the quality of the high priority service. In order to analyze the performance of our mechanism we introduce the stochastic analysis of a discrete-time queueing systems for the performance evaluation of the Active Queue Management (AQM) based congestion control mechanism called Weighted Random Early Detection (WRED) using a two-state Markov-Modulated Bernoulli arrival process (MMBP-2) as the traffic source. A two-dimensional discrete-time Harkov chain is introduced to model the Active-WRED mechanism for two traffic classes (Guaranteed Service and Best Effort Service) where each dimension corresponds to a traffic class with its own parameters.

• Journal of the Korean Society of Earth Science Education
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• v.6 no.1
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• pp.69-77
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• 2013

The study aims to figure out pre-service elementary teachers' knowledge understanding on 'stratum and rock' as well as teaching-learning types on the same topic. A total of 65 seniors in an advanced science education course at B University of Education joined the research to fulfill the purpose above. With PCK classification framework, the study examined pre-service teachers' knowledge understanding on 'stratum and rock' while it analyzed how the teachers would teach the given topic to students. The results of the study are presented as follows. First, it was observed that the pre-service elementary teachers have a great understanding on 'stratum and rock' that would be taught via a science textbook for elementary fourth graders. However, regarding terms in 'shale and limestone', they appeared to have a relatively short understanding. Second, PCK elements of the pre-service teachers related to 'stratum and rock' were analyzed and according to the results, the teachers would be interested in teaching model selecting in the teaching-learning strategy field while they would be well aware of how important it is for them to perform an experiment in a teaching process. The teachers also appeared to understand that the teacher question can be mutual complementary during class. However, it turned out that the teachers would have a very much low understanding on learners' prior knowledge as they particularly believe that learning could be significantly affected by the learners' perception level as well as their learning interest and motive. Third, the pre-service elementary teachers were told to design teaching plans on 'stratum and rock' so that the study could find out what learning-teaching methods the teachers would adopt to teach the topic. It was learned that the teachers would proceed with the class basically by giving the learners a descriptive explanation on the topic and also by using pictures and drawings to enhance the learners' understanding during the class.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.9-24
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• 1995

In this paper, we proposed and analysed two kinds of priority control mechanism to archive the cell loss rate requirement and the delay requirement of each class. The service classes of our concern are the high time priority class(class 1) and the high loss priority class(class 2). Two kinds of priority control mechanism is divided by the method of storing the arriving class 2 cell in buffer on case of buffer full. The first one is the method which discarding the arriving class 2 cell, the second one is the mothod which storing the arriving class 2 cell on behalf of pushing out the class 1 cell in buffer. In the proposed priority schemes, one cell of the class 1 is transmitted whenever the maximum K cells of the class 2 is transmitted on case of transmitting the class 1 cell and the class 2 cell sequentially. In this paper, we analysed the cell loss rate and the mean cell delay for each class of the proposed priority scheme by using the Markov chain. The analytical results show that the characteristic of the mean cell delay becomes better for the class 1 cell and that of the cell loss rate becomes better for the class 2 cell by selecting properly the cell transfer ratio according to the condition of input traffic.

• The Korean Journal of Health Service Management
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• v.11 no.3
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• pp.115-127
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• 2017

Objectives : To determine the relationship between of subjective recognition of social class and mental health. Method: The participants were adults with mental health experience over the age of 20 from the Korea Health Panel in 2013 (n=5,126). Methods : Data were analyzed using SPSS Statistics 22.0 The chi-square test and logistic regression analysis used to verify the relationship between subjective recognition of social class and mental health. Results : Lower subjective recognition of social class was associated with experience of depression and suicidal ideation. Other factors associated with depression experience were subjective health status, gender, age, marital status, type of medical care, disability, subjective health status, current smoking and frequency of drinking. Experience of suicidal ideation was, by contrast, associated with subjective health status, age, marital status, economic activity, private insurance, subjective health status and frequency of drinking. Conclusions : Health policies and institutions must be established to optimize health and preventive medicine approaches, especially or mental health as well as the provision of services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.739-740
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• 2013

This paper proposes a new dynamic bandwidth allocation algorithm for XGPON (10-Gigabit-capable passive optical network). The proposed algorithm uses a common service counter for each service class unlike to the existing algorithms. The unused bandwidth of a service class can be used for other service classes to increase bandwidth utilization. We illustrate examples to show the proposed algorithm is superior to existing algorithms.

• Journal of Korean Society for Quality Management
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• v.50 no.4
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• pp.843-861
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• 2022

Purpose: This study explores the impact of digital transformation (DT) strategies on gaining a competitive advantage in interactive educational services. Methods: We develop a service value proposition model by analyzing educational service elements to confirm the impact of DT in the classroom through case studies. This study focuses on educational services that DT has a positive impact on organizational competitiveness by providing opportunities for customers to engage in operational processes. This case study summarizes competitiveness using SWOT (strengths, weaknesses, opportunities, and threats) analysis. Results: The findings of the case study indicate that DT-enabled competitive factors contribute to an organization's competitive advantage. The study results present key resource as social cloud services, data combination, content sharing, and products/services. The online application that collects user data about education and shares class and evaluation information creates a new class operational process in the field of educational service for a value proposition of collection-merging-sharing with social cloud function. Conclusion: The results of this study can be used as a good guideline for educational service providers interested in applying DT for improved customer satisfaction and educational organizations' competitiveness. In addition, the study findings provide theoretical and practical implications on SWOT approaches to changing the educational service provision ways through digital transformation.

• Journal of The Korean Association For Science Education
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• v.30 no.6
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• pp.836-849
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• 2010

The purpose of this study is to analyze changes of competency observed in teaching of pre-service science teachers through the teaching evaluation and reflective journal writings on science class during the period of student-teaching at high school. To do this, we videotaped all the science classes of six pre-service teachers participating in this study, evaluated their class teachings, and collected moving video clips recorded in their classes, reflective journals, interviews, instructional materials, and teaching evaluation they have provided. From the "Standards for teaching evaluation of science instruction" developed by Korea Education Curriculum and Assessment, sixteen evaluation elements were selected and used for the analysis. According to our results, all preservice teachers show improvement of teaching performance in most of the class evaluation elements as the number of science classes increases. They presented the lowest improvement in the 'to design meaningful learning program,' which was one of the sixteen elements. However, there are substantial individual differences in the pre-service teachers' teaching competence on each evaluation element. Although they thought that 'understanding of scientific concepts' is the most important part of a science class in the beginning of student-teaching training, they showed changes in recognition that 'interaction and respect' and 'managing student behaviors' are also important in the end. They have recognized that writing a reflective journal, based on the video clips recorded in class and teaching evaluation, helps improve their teaching competency. In addition, improvement in teaching competency has influence upon career-orientation towards the school teacher in the future.

• Journal of The Korean Association For Science Education
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• v.33 no.6
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• pp.1087-1102
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• 2013

The purpose of this study is to find out the influence of reflective thinking facilitation program on reflection areas and its levels that pre-service science teachers present in the class teaching practice during the student-teaching period. Seven pre-service science teachers participated in this study and only four pre-service science teachers among them were additionally trained with the reflective program. Reflections of pre-service science teachers were mostly shown on class management, including attention and motivation, reflection and improvement for teaching activities, and interactions. However, the understanding of the science curricula and their reconstruction, and advance notice about the next class were not mentioned in their reflections. Pre-service science teachers who participated in the additional reflective program have shown more frequent reflections than those who only participated in the traditional student-teaching program. Pre-service science teachers, not trained with the reflective program, mostly showed descriptive reflection. However, those who participated in the reflective program have shown higher levels of reflections such as dialogic as well as the descriptive reflection. Therefore, pre-education program, reflective journal-writings, and science teachers' assessments on class and their feedback seem to improve the frequency and level of reflection for the pre-service science teachers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1A
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• pp.30-37
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• 2006

In this paper, we propose a QoS-aware efficient bandwidth re-provisioning scheme in a next generation wireless packet transport network. At the transport network layer, it classifies the traffic of the radio network layer into a real time class and a non-real time class. Using an auto-regressive time-series model and a given packet loss probability, our scheme predicts the needed bandwidth of the non-real time class at every re-provisioning interval. Our scheme increases the system capacity by releasing the unutilized bandwidth of the non-real time traffic class for the real-time traffic class while insuring a controllable upper bound on the packet loss probability of a non-real time traffic class. Through empirical evaluations using the real Internet traffic traces, our scheme is validated that it can increase the bandwidth efficiency while guaranteeing the quality of service requirements of the non-real time traffic class.

• Journal of Scientific & Technological Knowledge Infrastructure
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• s.4
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• pp.80-93
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• 2001

본 고에서는 멀티미디어 서비스를 위한 인터넷 QoS(Quality of Service) 기술요소를 살펴보았다. 즉 Intserv/RSVP 기반의 플로우 단위의 품질보장기술, Diffserv에 의한 CoS(class of service) 기술, SBM과 같은 대역폭관리기술 등을 살펴보고 이들 요소기술이 조합된 예를 살펴보았다. 또한 차세대 인터넷에서의 SLS(Service Level Specification)를 고찰했다.