• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.375-379
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• 2016

A current subtraction technique with parallel operation system is proposed to remove excessive current in touch screen application. The proposed current subtraction remove the current which go into the input node of charge amplifier. The value of subtraction current is same with current when touch screen is not touched. As a result, charge amplifier output is only proportional to variation of mutual capacitor, which make dynamic rage is increased. Also, Transmitter (Tx) driving signal and subtraction driving signal are out of phase each other. Thus, noise generated in Tx is cancelled. The proposed IC is implemented in a mixed-mode 0.18-um CMOS process. Overall system is designed for touch screen panel (TSP) with 16 driving lines and 8 sensing lines. 5-V supply voltages are used in the proposed circuits. For multiple Tx driving signal, Walsh codes are used and signal frequency is 300 khz. By using proposed technique, dynamic rage is improved 36 dB.

• ETRI Journal
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• v.37 no.3
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• pp.637-645
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• 2015

Common-mode noise (CMN) is an unresolved problem in wireless capsule endoscopy (WCE) systems. In a WCE system, CMN originates from various electric currents found within the human body or external interference sources and causes critical demodulation performance degradation. The differential operation, a typical method for the removal of CMN rejection, can remove CMN by subtracting two signals simultaneously received by two reception sensors attached to a human body. However, when there is impedance mismatching between the two reception sensors, the differential operation method cannot completely remove CMN. Therefore, to overcome this problem, we propose an enhanced CMN rejection method. The proposed method performs not only subtraction but also addition between two received signals. Then a CMN ratio can be estimated by sufficient accumulation of division operation outcomes between the subtraction and addition outputs during the guard period. Finally, we can reject the residual CMN by combining the subtraction and addition outputs.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.2
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• pp.83-92
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• 2013

RSA-CRT is a widely used algorithm that provides high performance implementation of the RSA-signature algorithm. Many previous studies on each operation step have been published to verify the physical leakages of RSA-CRT when used in smart devices. This paper proposes SAED (subtraction algorithm analysis on equidistant data), which extracts sensitive information using the event information of the subtraction operation in a reduction algorithm. SAED is an attack method that uses algorithm-dependent power signal changes. An adversary can extract a key using differential power analysis (DPA) of the subtraction operation. This paper indicates the theoretical rationality of SAED, and shows that its results are better than those of other methods. According to our experiments, only 256 power traces are sufficient to acquire one block of data. We verify that this method is more efficient than those proposed in previously published studies.

• Communications of Mathematical Education
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• v.23 no.3
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• pp.707-734
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• 2009

The purpose of the study was to investigate how children understand addition and subtraction of fractions and how their understanding influences the solutions of fractional word problems. Twenty students from 4th to 6th grades were involved in the study. Children's understanding of operations with fractions was categorized into "joining", "combine" and "computational procedures (of fraction addition)" for additions, "taking away", "comparison" and "computational procedures (of fraction subtraction)" for subtractions. Most children understood additions as combining two distinct sets and subtractions as removing a subset from a given set. In addition, whether fractions had common denominators or not did not affect how they interpret operations with fractions. Some children understood the meanings for addition and subtraction of fractions as computational procedures of each operation without associating these operations with the particular situations (e.g. joining, taking away). More children understood addition and subtraction of fractions as a computational procedure when two fractions had different denominators. In case of addition, children's semantic structure of fractional addition did not influence how they solve the word problems. Furthermore, we could not find any common features among children with the same understanding of fractional addition while solving the fractional word problems. In case of subtraction, on the other hand, most children revealed a tendency to solve the word problems based on their semantic structure of the fractional subtraction. Children with the same understanding of fractional subtraction showed some commonalities while solving word problems in comparison to solving word problems involving addition of fractions. Particularly, some children who understood the meaning for addition and subtraction of fractions as computational procedures of each operation could not successfully solve the word problems with fractions compared to other children.

• Journal of Educational Research in Mathematics
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• v.19 no.2
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• pp.307-319
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• 2009

Current school mathematics introduces addition/subtraction between natural numbers, fractions, decimal fractions, and square roots, step-by-step in order. It seems that, however, school mathematics focuses too much on learning the calculation method of addition/subtraction between each stages of numbers, to lead most of students to understand the coherent principle, lying in addition/subtraction algorithm between real numbers in all. This paper raises questions on this problematic approach of current school mathematics, in learning addition/subtraction. This paper intends to clarify the fact that, if we recognize addition/subtraction between numbers from the viewpoint of 'measuring' and 'common measure', as Dewey did when he argued that the psychological origin of the concept of number was measuring, then we could find some common principles of addition/subtraction operation, beyond the superficial differences among algorithms of addition/subtraction between each stages of numbers. At the end, this paper suggests the necessity of improving the methods of learning addition/subtraction in current school mathematics.

• Journal of the Korean School Mathematics Society
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• v.17 no.2
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• pp.235-249
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• 2014

In this paper, teaching contents in area between Korea and Japan's first grade math textbooks are compared. Based on the results of this comparison, implications for improving our grade 1 math textbooks are obtained as follows. Firstly, when describing the configuration of two-digit numbers, it needs to be considered that, after the mathematical description of a concrete material representing two-digit numbers, then it should be processed mathematically. Secondly, with respect to the composition and decomposition of numbers, use of the expression of 'some number and some number' needs to be considered. Thirdly, when reading addition expression and subtraction expression with an equal sign, the way of reading them with terms 'sum' and 'difference' respectively needs to be reconsidered. Fourthly, use of the distinct expression for the supplementing situation and the merging situation respectively and use of the distinct expression for the removing situation and the comparing situation respectively need to be considered. Fifthly, the jump in representing the expression of subtraction of two numbers as the expression of the subtraction or mixed operation of three numbers to explain (some number)-(some number) with borrowing need to be resolved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.681-684
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• 2015

Magnetization is very important in the ferro-magnetic physics and provides useful informations in the application field of magnetic devices. Generally, the only first acquired domain pattern is not helpful to recognize domain pattern. Many images are needed to visualize domain pattern through image processing. These images were obtained a 8-bit digital camera. The operation was the subtraction of pixel values of multi domain imanges from the images with 255 of pixel value, which was obtained in the saturated state of magnetic materials. The magnetic domain images was visualized gradually with increasing the number of subtracion operation. LABVIEW was used as an image processing tool and the optic microscope with a polarizer was used in this experiment.

• The Mathematical Education
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• v.59 no.3
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• pp.255-269
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• 2020

In this study, how to instruct the computational estimation of addition and subtraction was considered from the perspective of a 'intended-written-implemented' multi-dimensional curriculum. To this end, the 2015 revised elementary school mathematics curriculum as a intended curriculum and the 2015 revised first~sixth grade textbook as a written curriculum were analyzed with respect to how to instruct the computational estimation of addition and subtraction. As an implemented curriculum, a research study was conducted in relation to the method of instructing teachers about the computational estimation of addition and subtraction. As a result, first, it is necessary to discuss how to develop the ability to estimate and set it as a teaching goal and achievement standard in a separate curriculum to instruct it with learning content. Second, it is necessary to provide an opportunity to learn about various estimation methods by presenting specific activities so that students can learn the estimation itself in a separate operation method. Third, in order to improve the computational estimating ability of addition and subtraction, contents related to the computational estimation need to be included in the achievement criteria, and discussions on the expansion of the areas, and the diversification of the instructing time will be needed.

• Speech Sciences
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• v.15 no.2
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• pp.67-77
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• 2008

In this paper, we implemented a robust speech recognizer using the TMS320VC33 DSP. For this implementation, we had built speech and noise database suitable for the recognizer using spectral subtraction method for noise removal. The recognizer has an explicit structure in aspect that a speech signal is enhanced through spectral subtraction before endpoints detection and feature extraction. This helps make the operation of the recognizer clear and build HMM models which give minimum model-mismatch. Since the recognizer was developed for the purpose of controlling car facilities and voice dialing, it has two recognition engines, speaker independent one for controlling car facilities and speaker dependent one for voice dialing. We adopted a conventional DTW algorithm for the latter and a continuous HMM for the former. Though various off-line recognition test, we made a selection of optimal conditions of several recognition parameters for a resource-limited embedded recognizer, which led to HMM models of the three mixtures per state. The car noise added speech database is enhanced using spectral subtraction before HMM parameter estimation for reducing model-mismatch caused by nonlinear distortion from spectral subtraction. The hardware module developed includes a microcontroller for host interface which processes the protocol between the DSP and a host.

• Journal of the Korean School Mathematics Society
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• v.17 no.3
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• pp.409-435
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• 2014

This study examines relations between the 5th graders' fraction operation skills and error types on constructed-response items. As results, first, the participants have lower fraction operation skills on 'multiplication of fraction' than 'addition and subtraction of fraction'. Second, the participants have different error types depend on their constructed-response items. Most of error types which group with high ability made was 'leap of solving process', both groups error type with medium ability as well as low ability is 'misunderstanding of questions'. Third, the operation skills on 'addition and subtraction of fraction' have an influence on their operation skills on 'multiplication of fraction', and error types of 'understanding of questions' and 'understanding of solving process' have the most effects on the influence.