• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.803-808
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• 2001

Mathematical basis of interpretation of data from nondestructive evaluation (NDE) methods in bridge inspection is presented. In bridge inspection with NDE methods, NDE data are not assessments. NDE data must be interpreted as condition of element. Interpretation is then assessment. Correct assessments of conditions of bridge elements depend on the accuracy and variability in test data as well as on the uncertainty of correlations between attributes (what is measured) and conditions (what is sought in the inspection). Inaccuracy and variability in test data defines the qualify or NDE test. The qualify or test itself is important, but in view of condition assessment, the significance of uncertainty in correlations of attributes and conditions must be combined. NDE methods that are accurate in their measurements may still be found to be poor methods if attributes are uncertain indicators of condition of bridge elements. This paper reports mathematical presentation of inaccuracy and variability in test data and of uncertainty in correlation of attributes to element conditions with three examples of NDE methods.

• Bulletin of the Korean Mathematical Society
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• v.46 no.4
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• pp.803-819
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• 2009

In classical encryption schemes, data is encrypted under a single key that is associated with a user or group. In Ciphertext-Policy Attribute-Based Encryption(CP-ABE) keys are associated with attributes of users, given to them by a central trusted authority, and data is encrypted under a logical formula over these attributes. We extend this idea to the case where an arbitrary number of independent parties can be present to maintain attributes and their corresponding secret keys. We present a scheme for multi-authority CP-ABE, propose the first two constructions that fully implement the scheme, and prove their security against chosen plaintext attacks.

• Journal of Educational Research in Mathematics
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• v.25 no.3
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• pp.303-321
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• 2015

This research purposes to find out the mathematical cognitive characteristics of Korean students and compare it with that of TIMSS 2011 high-achieving countries based on the Cognitive Diagnostic Theory. Based on framework and questions of TIMSS 2011, we select cognitive attributes. Using the data of 8th grade students' mathematical achievement in TIMSS 2011, we compare and analyze the top 15-countries students' cognitive traits. As a result, cognition domain of TIMSS 2011 is reclassified as 9 cognitive attributes. we could distinguish between easy attributes and difficult attributes that students in each country relatively think. Especially, Students of Korea relatively think Recall/Recognize, Compute, Classify/Measure and Represent are easy. On the other hand, relatively they have difficulties in Retrieve, Implement, and Generalize. Based on this research result, It is necessary to establish an educational measures for each attributes which students have difficulties.

• Communications of the Korean Mathematical Society
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• v.20 no.4
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• pp.849-859
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• 2005

We present a new identity based authenticated key agreement protocol from pairings satisfying the required security attributes. The security of our protocol is based on the bilinear Diffie- Hellman assumption.

• The Mathematical Education
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• v.52 no.4
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• pp.465-481
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• 2013

In this study, 27 pre-service teachers presented virtual mathematics instruction to develop his/her own teaching practice ability. I found several attributes in their virtual mathematics instruction such as connecting contents, asking justification, encouraging students' communication, representing variously, and using ICT etc. These will be the characteristics of the future mathematics class. When peer pre-service teachers assess presenter's instruction quantitatively, there are differences in the results between expert and pre-service teachers. Pre-service teachers didn't find the elements of student self assessment or group assessment and communication activities at the virtual instruction. When they assess peers' virtual instruction qualitatively, the results are specific or new ones compared with the quantitative assessment elements. Thus I suggested some implications for the mathematics pre-service teachers' virtual instruction in the view of teacher education.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.61-76
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• 1995

The "optimal" solution for a decision making problem should be the one that best reflects the decision-maker's preference. For MADM (Multi-Attribute Decision-Making) problems, however, finding an optimal solution is difficult, especially when the number of alternatives, or that of attributes is relatively large. Most of the existing mathematical approaches arrive at a final solution on the basis of many unrealistic assumptions, without reflecting the decision-maker's preference structure exactly. To remedy this, some interactive methods have been proposed, but most of them require a large amount of information growing exponentially as the number of alternatives, or that of attributes increases. Therefore it is difficult for the decision-maker to maintain consistency throughout the decision making process. In this paper, an interactive method which finds optimal solutions for deterministic MADM problems with many attributes and alternatives is proposed. Instead of considering all the attributes simultaneously, this method partitions all the attributes into several mutually independent subgroups and considers one of them at each of preordered steps, where the alternatives are eliminated until the optimal one is obtained. The efficiency of the method lies in the fact that the amount of neccessary information is reduced significantly, and even further if a suboptimal solution is acceptable to the decision-maker.ion-maker.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.4
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• pp.635-643
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• 1997

The purpose of this paper is to propose an interactive method, using fuzzy Choquet's integral, which is designed to find out the mostly preferred solutions for deterministic MADM problems with many attributes and alternatives. The basic idea of the paper is essentially the same as that of the one we have published before[1]; subgrouping of attributes and eliminating of inefficient solutions. But the difference between these two methods lies in the fact that the present method evaluates and eliminates alternatives using fuzzy Choquet's integral on the basis of decision-maker's judgements about the relative importance of subgroups of attributes, rather than using mathematical programming on the basis of pair-wise comparisons of alternatives. If such information is obtainable from the decision-maker, the method can be proved to be much easier to understand and more efficient to compute.

• Asia pacific journal of information systems
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• v.1 no.1
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• pp.49-62
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• 1991

This paper examines the problems of database partitioning and file allocation in a fixed topology distributed computer network. The design objective is to make files as collections of attributes and to allocate these files to network nodes so that a minimum total transmission cost is achieved subject to storage capacity constraints. A mathematical model for solving the problem is formulated and, the resulting optimization problem is shown to fall in a class of NP-complete problems. A new heuristic algorithm is developed which uses the idea of allocating attributes according to the transaction requirements at each computer node and then making files using the allocated attributes. Numerical results indicate that the heuristic algorithm yields practicable low cost solutions in comparison with the existing methods which deal with the file allocation problems and database partitioning problems independently.

• Education of Primary School Mathematics
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• v.22 no.1
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• pp.1-12
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• 2019

This study examined the attention and attention shift of general students and mathematically gifted students about pattern by the types of mathematical patterns. For this purpose, we analyzed eye movements during the problem solving process of 5th general and mathematically gifted students using eye tracker. The results were as follows: first, there was no significant difference in attentional style between the two groups. Second, there was no significant difference in attention according to the generation method between the two groups. The diversion was more frequent in the incremental strain generation method in both groups. Third, general students focused more on the comparison between non-contiguous terms in both attributes. Unlike general students, mathematically gifted students showed more diversion from geometric attributes. In order to effectively guide the various types of mathematical patterns, we must consider the distinction between attention and attention shift between the two groups.

• Research in Mathematical Education
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• v.27 no.2
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• pp.157-173
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• 2024

Researchers continue to emphasize the centrality of proof in the context of school mathematics and the importance of proof to student learning of mathematics is well articulated in nationwide curricula. However, researchers reported that students' performance in proving tasks is not promising and students are not likely to see the need to prove a proposition even if they learned mathematical proof previously. Research attributes this issue to students' tendencies to accept an empirical argument as proof for a mathematical proposition, thus not being able to recognize the limitation of an empirical argument as proof for a mathematical proposition. In Korea, there is little research that investigated high school students' views about the need for proof in mathematics and their understanding of the limitation of an empirical argument as proof for a mathematical generalization. Sixty-two 11^th graders were invited to participate in an online survey and the responses were recorded in writing and on either a four- or five-point Likert scale. The students were asked to express their agreement with the need of proof in school mathematics and to evaluate a set of mathematical arguments as to whether the given arguments were proofs. Results indicate that a slight majority of students were able to identify a proof amongst the given arguments with the vast majority of students acknowledging the need for proof in mathematics.