• Management Science and Financial Engineering
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• v.12 no.2
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• pp.37-62
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• 2006

This paper considers the problem of designing logical tunnels in virtual private networks considering QoS guarantee which restricts the number of tunnel hops for each traffic routing. The previous researches focused on the design of logical tunnel itself and Steiner-tree based solution algorithms were proposed. However, we show that for some objective settings it is not sufficient and is necessary to consider both physical and logical connectivity at the same time. Thereupon, the concept of the layered network is applied to the logical tunnel design problem in virtual private networks. The layered network approach considers the design of logical tunnel as well as its physical routing and we propose a modified branch-and-price algorithm which is known to solve layered network design problems effectively. To show the performance of the proposed algorithm, computational experiments have been done and the results show that the proposed algorithm solves the given problem efficiently and effectively.

• Journal of Digital Contents Society
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• v.10 no.3
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• pp.375-380
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• 2009

Computer programming education can improve students' logical thinking and problem-solving ability. Therefore, it is essential tool to improve algorithmic thinking ability. We study how much Dolittle and Squeak influences improving elementary students' logical thinking ability. Thus, we divided 6th grade elementary students into two classes and then taught Dorittle and Squeak programming languages for 6 weeks, respectively. We compare and analyze each logical thinking ability and its sub-classifications. The results showed that Dorritle affects significant improvement, but not Squeak.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1371-1374
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• 2002

This paper compares four network con-figurations for using as the logical topology in multi- hop wavelength division multiplexing (WDM) networks. The regular network configurations studied in this paper axe ShuffleNet, de Bruijn graph, hypercube, and Man-hattan street network. Instead of using the weight mean hop distance of node placement problem for comparing optimum logical topology, we introduce a new objective function that includes h and the network cost. It can be seen that the network cost strongly depends on the logical topology selected for the implementation of the network. The objective of this paper is to find an optimum logical topology for WDM networks that gives low as well as low network cost.

• Korean Journal of Computational Design and Engineering
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• v.14 no.4
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• pp.225-233
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• 2009

The objective of this paper is to examine a construction method and verify PLC logic using the logical modeling and simulation of a virtual plant has complex manufacturing system and the domain of application is car body assembly line of automotive industrial operated by PLC Program. The proposed virtual plant model for the analysis of the construction method consists of three types of components which are virtual device, intermediary transfer and controller is modeled by logical model but it the case of the verification of PLC program, HMI and PLC logic in the field substitute for the controller. The implementation of the proposed virtual plant model is conducted PLC Studio which is an object-oriented modeling language based on logical model. As a result, proposed methods enable 3D graphics is designed in the analysis step to use for verification of PLC program without special efforts.

• Research in Mathematical Education
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• v.12 no.3
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• pp.201-213
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• 2008

The main purpose of this study is to explore the relationship between the 'logical reasoning skill' and performance in the logic unit that is part of the grade 9 syllabus in mathematics in Turkey. After the teaching of the logic unit, an achievement test, a general skills test and the test of logical reasoning were administered to the 80, 9th year high school students. Pearson Moments Correlation coefficient was used for the analysis of the data to determine the relations between the variables. In addition to that to obtain the most suitable regression explaining the students' performances in the logic unit, stepwise multiple regressions analysis was used. At the end of the study, statistically significant relations were found between the students' performance in the logic unit and their logical reasoning skills, their results of the shape recognition test from the general skills battery and their overall performance in the mathematics lesson.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.722-729
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• 2005

Ethernet passive optical networks (EPONs) are an emerging access network technology which has a point-to-multipoint topology. EPONs operate point-to-multipoint in the OLT-ONU direction, and point-to-point in the ONU-OLT direction. To support point-to-point emulation and shared LAM emulation, EPONs use multi-point control protocol (MPCP). The MPCP uses logical link identification (LLID) field for frame tagging and filtering between the OLT and ONUs. In this paper, I propose logical-group identification (LGID) for logical link-based multicasting or VLAN services in EPONs. Using LGID with new frame tagging and filtering rules, EPONs support differentiated multimedia broadcasting or multicasting services. Additionally, EPONs can support logical link-based VLAN services that divides ONUs into several subsets.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.3
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• pp.103-110
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• 2013

Logical Effort [1, 2] is a simple hand-calculated method that measures quick delay estimation. It has the advantage of reducing the design cycle time. However, it has shortcomings in designing a path for minimum area or power under a fixed-delay constraint. The method of overcoming the shortcomings is shown in [3], but it is constrained for a single logical path. This paper presents an advanced gate sizing method in multiple logical paths based on the equal delay model. According to the results of the simulation, the power dissipation for both the existing logical effort method and proposed method is almost equal. However, compared with the existing logical effort method, it is about 52 (%) more efficient in space.

• The Journal of Korean Association of Computer Education
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• v.9 no.3
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• pp.85-96
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• 2006

This study analyzes a phenomenon observed in the problem-solving process using ICT that field learners prioritize functional and logical fields. The purpose of this study is to anticipate the future direction of education utilizing ICT and to explore what effort is needed to increase balanced ability of utilizing ICT in the area of education. To analyze the patterns of ICT usage in education, students were asked to solve the problems including functional and logical requests by using the program of framing document. That results were marked in accordance with standards framed in both functional and logical fields. As a result, students utilized the ICT functional field more than logical one. Therefore, we confirm learning through ICT is more effective on functional sides than on logical sides. We also confirm the excellency of ICT's functional sides in such variables as major, grade, computer capability and qualification, etc.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.677-688
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• 2001

The purposes of this study are to investigate the school science high achievers' achievements in enrichment physics, logical thinking level, and to analyze the relationship between logical thinking level and the achievement in enrichment physics of high achievers in science. The subjects were 357th and 8th graders who achieved highly in school science. To assess their achievements in enrichment physics, we developed a new test consisting of descriptive problems which were based on middle school curriculum. Those problems require one or two steps of thinking process, not simple knowledge of science. To assess logical thinking level, we used the instrument called GALT(Group Assessment of Logical Thinking) developed by Roadranka et al. The results showed that the school science high achievers' average achievement in enrichment physics was low, 56.3 out of 150, which indicated that they had not done much of enrichment learning beyond middle school science curriculum. Just only 54% of the school science high achievers are in formal logical thinking level. From the analysis of relationship between their logical thinking level and the achievement in enrichment physics, the value of the correlation coefficient was 0.174, which means that they are not almost correlated. Therefore, it is not desirable to judge science gifted children just from achievement in school science or enrichment physics, so both(logical thinking and the achievement in enrichment physics) tests should be taken for selecting gifted student.

• Journal of Gifted/Talented Education
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• v.23 no.3
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• pp.335-354
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• 2013

The purpose of this study was to investigate cognitive development and logical thinking formation levels of elementary gifted students and to compare with those of elementary regular students. For this purpose, 79 gifted elementary school students and 114 regular elementary school students in Kyunggi Province were participated, and GALT(Group Assessment of Logical Test) was administered to them. The results obtained in this study were as follows. First, the logical thinking scores of elementary gifted students were significantly higher than general students'(p<.05). Comparing the distribution of cognitive development level, elementary gifted students showed higher ratio in formal operation and lower ratio in concrete operation compared to the general students. It was interpreted that the cognitive development of gifted students preceded general students'. Second, analyzing according to the grade of elementary gifted students, logical thinking scores were significantly different between 5th graders and 6th graders(p<.05). Compared to 5th graders, logical thinking and formal operation ratio of 6th gifted graders showed significantly higher. The scores of four logical thinking areas except for conservational logic and correlational logic of 6th gifted graders showed significantly higher than 5th gifted graders'. Both 5th and 6th graders showed the highest formation ratio in combinational logic, and the lowest ratio in correlational logic. Third, logical thinking scores of gifted students according to gender did not show a significant difference(p>.05). The gifted boys reached formal operation more than gifted girls, but stayed more in the concrete operation. There was gender difference in correlational logic. The gifted girls showed significantly higher than gifted boys in correlational logic(p<.05).