• The Mathematical Education
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• v.31 no.2
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• pp.109-119
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• 1992

The primary purpose of the present study is to provide the sources to improve the mathematical problem solving performance by analyzing the effects of the belief systems and the misconceptions of the middle school students in solving the problems. To attain the purpose of this study, the reserch is designed to find out the belief systems of the middle school students in solving the mathematical problems, to analyze the effects of the belief systems and the attitude on the process of the problem solving, and to identify the misconceptions which are observed in the problem solving. The sample of 295 students (boys 145, girls 150) was drawn out of 9th grade students from three middle schools selected in the Kangdong district of Seoul. Three kinds of tests were administered in the present study: the tests to investigate (1) the belief systems, (2) the mathematical problem solving performance, and (3) the attitude in solving mathematical problems. The frequencies of each of the test items on belief systems and attitude, and the scores on the problem solving performance test were collected for statistical analyses. The protocals written by all subjects on the paper sheets to investigate the misconceptions were analyzed. The statistical analysis has been tabulated on the scale of 100. On the analysis of written protocals, misconception patterns has been identified. The conclusions drawn from the results obtained in the present study are as follows; First, the belief systems in solving problems is splited almost equally, 52.95% students with the belief vs 47.05% students with lack of the belief in their efforts to tackle the problems. Almost half of them lose their belief in solving the problems as soon as they given. Therefore, it is suggested that they should be motivated with the mathematical problems derived from the daily life which drew their interests, and the individual difference should be taken into account in teaching mathematical problem solving. Second. the students who readily approach the problems are full of confidence. About 56% students of all subjects told that they enjoyed them and studied hard, while about 26% students answered that they studied bard because of the importance of the mathematics. In total, 81.5% students built their confidence by studying hard. Meanwhile, the students who are poor in mathematics are lack of belief. Among are the students accounting for 59.4% who didn't remember how to solve the problems and 21.4% lost their interest in mathematics because of lack of belief. Consequently, the internal factor accounts for 80.8%. Thus, this suggests both of the cognitive and the affective objectives should be emphasized to help them build the belief on mathematical problem solving. Third, the effects of the belief systems in problem solving ability show that the students with high belief demonstrate higher ability despite the lack of the memory of the problem solving than the students who depend upon their memory. This suggests that we develop the mathematical problems which require the diverse problem solving strategies rather than depend upon the simple memory. Fourth, the analysis of the misconceptions shows that the students tend to depend upon the formula or technical computation rather than to approach the problems with efforts to fully understand them This tendency was generally observed in the processes of the problem solving. In conclusion, the students should be taught to clearly understand the mathematical concepts and the problems requiring the diverse strategies should be developed to improve the mathematical abilities.

• Journal of Power Electronics
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• v.5 no.2
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• pp.142-150
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• 2005

This paper presents a systematic approach to study the carrier based pulse width modulation (PWM) techniques applied to diode-clamped and cascade multilevel inverters by using multi-modulating patterns. This method is based on the description of controllable redundant parameters in the modulating signals. A unified mathematical formulation is presented for carrier based PWM methods, which obtains outputs similar to the corresponding space vector PWM. A full and separate control of the fundamental voltage, vector redundancies and phase redundancies can be obtained in the carrier based PWM. In this paper, the proposed PWM method and corresponding algorithm for generating multi-modulating signals will be formulated and demonstrated by our simulations.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.6
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• pp.751-763
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• 2014

The paper is written to determine the optimal search pattern through search effects assessment on underwater targets. 5 types of search patterns are introduced such as, M-type pattern, W-type pattern, rectangular pattern, 4-type pattern and square pattern, In addition, Operational effectiveness analysis model is developed to obtain the optimum search pattern. The algorithms and mathematical models are also suggested to analyze the required search times, AUV's movement patterns, moving distances, overlapping areas and so on.

• Journal for History of Mathematics
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• v.20 no.3
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• pp.43-58
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• 2007

We review the eastern frog jump game and the western solitaire to apply the Baduk Pieces Game to mathematical education. This study introduce a didactical method of Baduk Pieces Game which is constructed with simplification, generalization, and extension. This didactical applications of the Baduk Pieces Game gives the students opportunities of patterns, generalization, and problem solving strategies.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.386-388
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• 2001

The change of the electricity charge from cost base to price base due to the introduction of the electricity market competition causes consumer to choose a variety of charge schemes and a portion of loads to be affected by this change. Besides, it is required the index that consolidate the price volatility experienced on the power exchange with gaming and strategic bidding by suppliers to increase profits. Therefore, in order to find a mathematical model of the sensitively-responding-to-price loads, the price-sensitive load model is needed. And the development of state-of-the-art technologies affects the electricity price, so the diffusion of high-efficient end-uses and these price affect load patterns. This paper shows the analysis on learning curves algorithms which is used to investigate the correlation of the end-uses' price and load patterns.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.435-437
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• 2001

The change of the electricity charge from cost base to price base due to the introduction of the electricity market competition causes consumer to choose a variety of charge schemes and a portion of loads to be affected by this change. Besides, it is required the index that consolidate the price volatility experienced on the power exchange with gaming and strategic bidding by suppliers to increase profits. Therefore, in order to find a mathematical model of the sensitively-responding-to-price loads, the price-sensitive load model is needed. And the development of state-of-the-art technologies affects the electricity price, so the diffusion of high-efficient end-uses and these price affect load patterns. This paper shows the analysis on learning curves algorithms which is used to investigate the correlation of the end-uses' price and load patterns.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.613-619
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• 2008

A method to produce a desired current pattern in a multiple-source EIT system using voltage sources is presented. Application of current patterns to a body is known to be superior to the application of voltage patterns in terms of high spatial frequency noise suppression, resulting in high accuracy in conductivity and permittivity images. Since current sources are difficult and expensive to build, the use of voltage sources to apply the current pattern is desirable. An iterative algorithm presented in this paper generates the necessary voltage pattern that will produce the desired current pattern. The convergence of the algorithm is shown under the condition that the estimation error of the linear mapping matrix from voltage to current is small. Simulation results are presented to illustrate the convergence of the output current.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.135-141
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• 2002

Recently, in the metro railways, researches on the skip-stop operation and development of the double deck train-set are active, which is to improve the service quality through reducing the passenger travel time and suppling seating service. Constructing new line or reforming the existent line needs huge amount of budget. Therefore, previous to start these large scale projects, scrutiny on benefit improvement, cost reduction and those optimal trade-off is indispensable. In this paper, a quantitative analysis to determine the optimal train service patterns and train-sets necessary is proposed, under the skip-stop operation condition in the metro railways. The analysis models are formulated in mathematical programming model, and tested validity using the LINGO 7.0.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.147-161
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• 2002

In novelty detection, one attempts to discriminate abnormal patterns from normal ones. Novelty detection is quite difficult since, unlike usual two class classification problems, only normal patterns are available for training. Auto-Associative Multi-Layer Perceptron (AAMLP) has been shown to provide a good performance based upon the property that novel patterns usually have larger auto-associative errors. In this paper, we give a mathematical analysis of 2-layer AAMLP's output characteristics and empirical results of 2-layer and 4-layer AAMLPs. Various activation functions such as linear, saturated linear and sigmoid are compared. The 2-layer AAMLPs cannot identify non-linear boundaries while the 4-layer ones can. When the data distribution is multi-modal, then an ensemble of AAMLPs, each of which is trained with pre-clustered data is required. This paper contributes to understanding of AAMLP networks and leads to practical recommendations regarding its use.

• Education of Primary School Mathematics
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• v.10 no.1 s.19
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• pp.15-28
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• 2007

From a social constructivists' perspective, knowledge is not transmitted by language but it is constructed by social interactions with others. That is, it is viewed in social constructivism that learning is a process in which knowledge is constructed by communicative interactions with more capable others. In this vein, a class might be analyzed and characterized in terms of interactional patterns of teacher-student and student-student in class. For this, a primary math class was selected and observed and it was analyzed by the Flanders category system to investigate the effects of the math teaching based on verbal interactions on the learning of math. The class was taught in a teacher-centered and direct way but in the class math knowledge was taught through univocal communications in the form of question-answer. The results of this study appeared to suggest that verbal interactional patterns should take place frequently in math teaching in the sequence of a teacher's questions$\to$students' extensive responses $\to$ positive feedback for the students' responses by the teacher $\to$ the acceptance of the students' responses $\to$ the teacher's explanation or students' questions. In other words, math might be taught more effectively through the verbal discourse patterns proposed in this study.