• Communications of Mathematical Education
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• v.29 no.3
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• pp.533-551
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• 2015

Problem posing in school mathematics is generally regarded to make a new problem from contexts, information, and experiences relevant to realistic or mathematical situations. Also, it is to reconstruct a similar or more complicated new problem based on an original problem. The former is called as problem generation and the latter is as problem reformulation. The purpose of this study was to explore the co-relation between problem generation and problem reformulation, and the educational effectiveness of each problem posing. For this purpose, on the subject of 33 pre-service secondary school teachers, this study developed two types of problem posing activities. The one was executed as the procedures of [problem generation${\rightarrow}$solving a self-generated problem${\rightarrow}$reformulation of the problem], and the other was done as the procedures of [problem generation${\rightarrow}$solving the most often generated problem${\rightarrow}$reformulation of the problem]. The intent of the former activity was to lead students' maintaining the ability to deal with the problem generation and reformulation for themselves. Furthermore, through the latter one, they were led to have peers' thinking patterns and typical tendency on problem generation and reformulation according to the instructor(the researcher)'s guidance. After these activities, the subject(33 pre-service teachers) was responded in the survey. The information on the survey is consisted of mathematical difficulties and interests, cognitive and affective domains, merits and demerits, and application to the instruction and assessment situations in math class. According to the results of this study, problem generation would be geared to understand mathematical concepts and also problem reformulation would enhance problem solving ability. And it is shown that accomplishing the second activity of problem posing be more efficient than doing the first activity in math class.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1435-1441
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• 2018

Online signature verification is one of the simple and efficient methods of identity verification and has less resistance than other biometric technologies. To handle signature verification as a classification problem, it is necessary to gather forgery signatures, which is not easy in most practical applications. It is not easy to obtain a large number of genuine signatures either. In this paper, one class SVM is used to tackle the forgery signature problem and someone else's signatures are used as general handwriting data to solve the genuine signature problem. Someone else's signature does not share shape-based features with the signature to be verified, but it contains the general characteristics of a signature and useful in verification. Verification rate can be improved by using the general handwriting data, which can be confirmed through the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.78-85
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• 2012

Low-Voltage power lines should equip surge protection devices which protect electronic equipments and human lives against lightning and abnormal voltages. Data transmission capacity of the power line is determined by frequency characteristics of the surge protective devices. To analyze the effects of surge protective devices on the data transmission performance, various combinations of installation methods are tested which include ZnO varistor elements that is compatible with class I, class II and class III. The result claims that ZnO varistor for class III is found to be one of the main factors that deteriorates the transmission performance. To overcome this problem a serial connection methed between Gap type SPD and ZnO varistor is proposed. With the proposed scheme, laboratory experimental results show that the data transmission performance can be improved up to 91.9[%] with proper SPD combination.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.190-196
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• 2004

In this paper, we address a layout design problem, PTL[3], for determining an optimal 3-class-based dedicated linear storage layout in a class of unit load storage systems. Our objective is to minimize the expected single command travel time. We analyze PTL[3] to derive a fundamental property that an optimal solution to PTL[3] is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. Using the property and partial enumeration, we construct an efficient exact algorithm with O $(n\;{\lceil}\;log\;n\;{\rceil}\;)$ for solving PTL[3].

• Journal of the Korean School Mathematics Society
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• v.4 no.2
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• pp.115-123
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• 2001

In its seventh revision to start in 2001, mathematics will have a new emphasis in the middle school curriculum. Mathematics subject is now composed of practical things in the use of mathematics. Also, the future of new generation, which has been known as the information age, places much focus on problem-solving in order to collect, analyze, synthesize, and judge various kinds informations. This demand of problem-solving ability is not only related with mathematical education but, along the entire educational process, its related to actual life. With this change of social structure, the importance of school education is increasing rapidly. Therefore, in order to grow abilities and create new knowledge, adapted this new method of self-oriented learning in groups to middle school 2nd graders for one year, the results were as follows : 1. Students developed their ability of the use of mathematical terms and signs correctly. 2. Students' mathematical knowledge and problem-solving ability improved as they had increased interest in mathematics. 3. Students' peership was enhanced through their communication and cooperative activities in groups during the class. 4. Students themselves were more willing to volunteer and participate during the class.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.17 no.1
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• pp.82-89
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• 2010

Purpose: The purpose of this study was to compare nursing students before using problem-based learning and after the experience in: class satisfaction, tendency to critical thinking, learning attitude and motivation. Method: The data were collected on March 20 and June 5, 2008. The PBL study was given for 15 weeks from March through June involving 216 junior nursing students. To test effects of PBL, a one group pretest-posttest design was used. Statistical analysis was performed with SPSS 13.0. Paired t-test, $x^2$-test, and Pearson correlation coefficient were performed. Results: The results are summarized as follows: Following PBL, the students scored significantly higher on the class satisfaction (t=-3.321, p= .001), tendency to critical thinking (t=-2.218, p= .034), learning attitude (t=-2.910, p= .004) and motivation (t=-4.407, p<.001). The Pearson correlation coefficients among the three variables were significantly positive. Conclusion: This study contributes to our understanding of outcomes from the PBL approach. The students undertaking PBL showed that they developed a more positive attitude with their educational experience. Also, students' tendency to think critically improved through the use of the PBL approach.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.117-131
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• 2018

PBL is expected to be very useful in the engineering project course that leads students to active learning in problem solving process. But it is not actively utilized because of various problems. In this study, modified PBL lectures were laid out for a course that practice UX design process. Modified PBL lectures provide theoretical class and two PBL practices. The variant is that the problem design is made by the students themselves on a weekly basis, rather than by the instructor, and that the two PBL processes consist of one project. The results of this study are meaningful as a basic data in PBL-based engineering college project class. Additional discussion of how to evaluate grades needs to be specified.

• Korean Management Science Review
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• v.30 no.1
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• pp.1-14
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• 2013

We conduct the future studies suggested by Park and Seo [3]. They considered a seat inventory control problem in which flights depart sequentially during a similar time-interval and passengers purchase available seats depending on individual customer choice behavior. Customer choice behavior can lead to one among a horizontal shift, a diversion-up, and a booking loss when a desired fare class is unavailable. We investigate how seat availability calculation method, booking limit control mechanism, seat inventory capacity, number of booking class, type of seat demand influence on revenues in an airline industry through thorough computer simulation experiments.

• International Journal of Contents
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• v.1 no.1
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• pp.21-28
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• 2005

This paper is about the hardness of Leader Election problem in asynchronous distributed systems in which processes can crash but links are reliable. Recently, the hardness of a problem encountered in the systems is defined with respect to the difficulty to solve it despite failures: a problem is easy if it can be solved in presence of failures, otherwise it is hard [9]. It is shown in [9] that problems are classified as three classes: F (fault-tolerant), NF (Not fault-tolerant) and NFC (NF-completeness). Among those, the class NFC is the hardest problem to solve. It is also shown in [9] that the construction of Perfect Failure Detector (problem P) belongs to NFC. In this paper, we show that Leader Election is also one of NFC problems by using a general reduction protocol that reduces the Leader Election Problem to P. We use a formulation of the Leader Election problem as a prototype to show that it belongs to NFC.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.129-134
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• 2012

In this paper we review a bi-aspect nonparametric test for the two-sample problem under the location translation model and propose a new one to accommodate a more broad class of underlying distributions. Then we compare the performance of our proposed test with other existing ones by obtaining empirical powers through a simulation study. Then we discuss some interesting features related to the bi-aspect test with a comment on a possible expansion for the proposed test as concluding remarks.