• Journal of Computing Science and Engineering
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• v.3 no.4
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• pp.195-215
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• 2009

Worst-case execution time (WCET) analysis is critical for hard real-time systems to ensure that different tasks can meet their respective deadlines. While significant progress has been made for WCET analysis of instruction caches, the data cache timing analysis, especially for set-associative data caches, is rather limited. This paper proposes an approach to safely and tightly bounding data cache performance by computing the worst-case stack distance of data cache accesses. Our approach can not only be applied to direct-mapped caches, but also be used for set-associative or even fully-associative caches without increasing the complexity of analysis. Moreover, the proposed approach can statically categorize worst-case data cache misses into cold, conflict, and capacity misses, which can provide useful insights for designers to enhance the worst-case data cache performance. Our evaluation shows that the proposed data cache timing analysis technique can safely and accurately estimate the worst-case data cache performance, and the overestimation as compared to the observed worst-case data cache misses is within 1% on average.

• The Journal of Korean Association of Computer Education
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• v.3 no.1
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• pp.135-142
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• 2000

Recently the user of distance education system using Intemet-Web are increasing rapidly. This paper shows that Hierarchical WBI documents generator by using CGI is devised and applied to development of distance education system for group-level spoken english. This overcomes the problems of the ready-made programs, which took a lot of time and cost. To generate WBI documents, The key is established to each document saved in server by types of the hierarchical structure and is transmitted to client. By client transmitting this key to server when next documentary is required. Sever can know what documents the client needs. The WBI documentary generator tells the keys transmitted from the client, automatically generates a new documentary to send, and delivery it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2324-2330
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• 2010

In middle and high school to learn the principles of fluid mechanics to Experiments in space and time constraints and difficulties for the study of the principles of fluid mechanics to the problem is superficial. In this paper, Pascal's principles, Archimedes' Principle, Bernoulli's Theorem, etc. learning about the fluid mechanics and implemented in Web Browser, In connection with flash and HTML, web simulation is to implement. Web Based Instruction program that implemented a comparative analysis became an effect of 15% to industrial total high school students in satisfaction, Interest, Achievement. The fluid mechanics education through engineering design and web design through the actual web server is implemented on the Internet over broadband. Department of Education, this study the fluid mechanics and the Internet will contribute to the development of distance education.

• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.55-66
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• 1999

In mathematics education, teaching-learning activity can be divided largely into the understanding the mathematical concepts, derivation of principles and laws acquirement of the mathematical abilities. We utilize various media, teaching tools, audio-visual materials, manufacturing materials for understanding mathematical concepts. But sometimes we cannot define or explain correctly the concepts as well as the derivation of principles and laws by these materials. In order to solve the problem we can use the computer. In this paper, ′the process of the length of curve being equal to the sum of the vectors when intervals get smaller′ and ′the process of calculating volume of spinning curve by using definite integral.′ Using the computers is more visible than other educational instruments like blackboards, O.H.Ps., etc. Also it can help students with solving mathematical problems intuitively. Consequently more effective teaching-learning activity can be done. Usage of computers is the best method for improving the mathematical abilities because computers have functions of the immediate reaction, operation, reference and deduction. One of the important characters of mathematics is accuracy, so we use computers for improving mathematical abilities. This paper is about the program focused on the part of "the application of definite integral", which exists in mathematical curriculum the second and third grade of high school. When this study is used for students as assisting materials, it is expected the following educational effect. 1. Students will have precise concepts because they can understand what they learn intuitively. 2. Students will have positive thought by arousing interests of learning because this program is composed of pictures, animations with effectiveness of sound. 3. It is possible to change the teacher-centered instruction into the student-centered instruction. 4. Students will understand the relation between velocity and distance correctly because they can see the process of getting the length of curve by vector through the monitor. For the purpose of increasing the efficiencies and qualities of mathematics education, we have to seek the various learning-teaching methods. But considering that no computer can replace the teacher′s role, teachers have to use the CIA program carefully.

• The KIPS Transactions:PartD
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• v.9D no.3
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• pp.511-522
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• 2002

WBI (Web-Based Instruction), a web-based tool for teaching the students at a long distance, makes possible to Interact between learners and instructors, provides a wide variety of learning materials, has an advantage of overcoming spatial constraints. In this paper, as a model of using the web for education, a web-based education-evaluation system has been designed and implemented. Web-based education-evaluation system has to be equipped with both of the online setting question mode and the upload setting question mode, the former makes questions on web and the latter uploads the setted questions on offline with settling a defeat of the existing systems on setting questions. And the system has to be equipped with the function of analyzing the questions that gives teacher several kinds of analysis information and makes possible to feedback to questions by adjusting the difficulty and revising the questions. In this paper, a system that reflects the above requirements has been designed and implemented with PHP script language and MySQL database system.

• Education of Primary School Mathematics
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• v.17 no.1
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• pp.1-16
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• 2014

The purpose of this study is to analyze whether analogy distance and mathematical knowledge affect on transfer problems solving with different analogy distance. To conduct the study, transfer problems were classified into multiple categories: mathematical word problem based on rates, science word problem based on rates, and real-life problem based on rates with different analogy distance. Then analysed there are differences in participants' transfer ability and which mathematical knowledge contributes to the solution on over the three transfer problem. The study demonstrated a statistical significant difference(.05) in participants' three transfer problem solving and a gradual decrease of the participants' success rates of on transfer problems solving. Moreover, conceptual knowledge influenced transfer problem solving more than factual knowledge about rates. The study has an important implications in that it provided new direction for study about transfer of learning, and also show a good mathematics instruction on where teachers will put the focus in mathematical lesson to foster elementary students' transfer ability.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.629-641
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• 2016

Understanding of how teachers change instruction can help predict what kind of educational materials is supportive or appropriate. On the basis of this idea, we explored elementary teachers' PCK progression on specific topics of astronomy: planet size and distance in solar system. To identify the development of PCK over time, we utilized learning progression (LP) as a conceptual framework. The progression of teacher PCK can also be illustrated as the hypothetical pathway from novice to expert like LP. Eight 5th grade elementary teachers participated in this study. We observed participating teachers' astronomy classes with the same topic. In order to document topic-specific PCK of participating teachers, we developed an analytic protocol consisting of four categories: knowledge of curriculum, knowledge of teaching strategies, knowledge of assessment, and astronomical thinking practice. In addition, we monitored the changes in the four participating teachers' PCK for two years in order to validate the evidences of the PCK progression. Participating teachers in this study took some intervention by attending a four-week pre-meeting with the researchers to profile an adaptive instruction. Through this research, we profiled four and five different levels of PCK progressions in three knowledge components (curriculum, teaching strategies, student assessment) and one astronomical thinking practice (systems thinking), respectively. Participating teachers demonstrated various levels and pathways in each component of PCK. This study released the empirical evidences in fostering instructional scaffolding, which is appropriate to the level of PCK of science teachers on specific topic.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.59-70
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• 2009

Purpose: The purpose of this study was to investigate the degree of compliance with supportive periodontal therapy(SPT), to determine if any significant differences existed in the characteristics of compliant, erratically compliant and non-compliant patients and to identify reasons for poor compliance. Materials and methods: Four hundred five patients who initially visited between July 2003 and December 2004 and were treated until June 2005 were retrospectively evaluated for their compliance with SPT in terms of attendance for a recommended schedule of visits. Patients' compliance was classified as complete compliance(attended more than 80% of the recommended appointments), erratic compliance(attended less than 80% of the recommended appointments or discontinued) and non-compliance(did not return for SPT). Analysis was made for each group to correlate the degree of compliance with gender, age, smoking, distance between their houses and the hospital, disease severity, type of therapy, implant, plaque control instruction and systemic diseases. Tele research of erratically compliant and non-compliant patients was carried out to identify reasons for their poor compliance. Results: Only 24.7% of the patients were in complete compliance. The highest drop-out rate(32.4%) occurred in the first year. A significantly greater percentage of non-smokers and patients who finished plaque control instruction were in complete compliance. A significantly greater percentage of patients without implant and patients who had been treated by only scaling and root planing were in non-compliance. More males were found to be compliant with SPT, although this was marginally significant. There were no significant differences between compliant, erratically compliant and non-compliant patients with regard to age, distance, disease severity and systemic disease. The survey revealed that the main reasons for poor compliance with SPT were inconvenient location and insufficient time. Conclusion: Patients' compliance with SPT was poor and the highest drop-out rate(32.4%) occurred in the first year. Significant relationships were found between the degree of compliance and smoking, type of therapy, implant, plaque control instruction and gender.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.419-425
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• 2020

There are many accident risks in logging operation of forestry such as struck by felled trees and caught in, under, or between felled trees. These accidents are primarily occurred by not keeping a safe distance between workers. According to the forestry safety instruction, workers are not supposed to go into the safety zone which is a circle with a radius of more 2 times the height of felling tree. However, this rule does not keep because of poor safety consciousness, poor sight and extreme noise of logging operation machines. This problem causes many major accidents every year. To solve this problem, we made forestry safety helmets based on IoT technology. These helmets have functions to make a visual and an acoustic alarm signal when reach the distance between workers within 20 meters. We developed the algorithm to operate the helmet's functions and conducted tests to check the functions. As a result of tests, we assured the normal system operating conditions.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.209-214
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• 1998

The advent of powerful hardware and advances in high speed networks enabled synchronous learning, with teachers and students being geographically distributed but connected via computer networks. Today's synchronous learning systems are mainly based on video conferencing technology which provides audio, video, and joint editing of documents only, but does not take into account the specific requirements of teaching, for instance, controlling the course of instruction, raising hands, or reference pointing. A shared whiteboard is often the core part of these systems. Therefore, in this paper, we look into implementation issues in whiteboards of distance learning systems. Particularly, system architectures and concurrency control mechanisms are considered.